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TOMOYO Linux Cross Reference
Linux/fs/ceph/caps.c

Version: ~ [ linux-6.11-rc3 ] ~ [ linux-6.10.4 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.45 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.104 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.164 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.223 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.281 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.319 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 #include <linux/ceph/ceph_debug.h>
  3 
  4 #include <linux/fs.h>
  5 #include <linux/kernel.h>
  6 #include <linux/sched/signal.h>
  7 #include <linux/slab.h>
  8 #include <linux/vmalloc.h>
  9 #include <linux/wait.h>
 10 #include <linux/writeback.h>
 11 #include <linux/iversion.h>
 12 #include <linux/filelock.h>
 13 
 14 #include "super.h"
 15 #include "mds_client.h"
 16 #include "cache.h"
 17 #include "crypto.h"
 18 #include <linux/ceph/decode.h>
 19 #include <linux/ceph/messenger.h>
 20 
 21 /*
 22  * Capability management
 23  *
 24  * The Ceph metadata servers control client access to inode metadata
 25  * and file data by issuing capabilities, granting clients permission
 26  * to read and/or write both inode field and file data to OSDs
 27  * (storage nodes).  Each capability consists of a set of bits
 28  * indicating which operations are allowed.
 29  *
 30  * If the client holds a *_SHARED cap, the client has a coherent value
 31  * that can be safely read from the cached inode.
 32  *
 33  * In the case of a *_EXCL (exclusive) or FILE_WR capabilities, the
 34  * client is allowed to change inode attributes (e.g., file size,
 35  * mtime), note its dirty state in the ceph_cap, and asynchronously
 36  * flush that metadata change to the MDS.
 37  *
 38  * In the event of a conflicting operation (perhaps by another
 39  * client), the MDS will revoke the conflicting client capabilities.
 40  *
 41  * In order for a client to cache an inode, it must hold a capability
 42  * with at least one MDS server.  When inodes are released, release
 43  * notifications are batched and periodically sent en masse to the MDS
 44  * cluster to release server state.
 45  */
 46 
 47 static u64 __get_oldest_flush_tid(struct ceph_mds_client *mdsc);
 48 static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
 49                                  struct ceph_mds_session *session,
 50                                  struct ceph_inode_info *ci,
 51                                  u64 oldest_flush_tid);
 52 
 53 /*
 54  * Generate readable cap strings for debugging output.
 55  */
 56 #define MAX_CAP_STR 20
 57 static char cap_str[MAX_CAP_STR][40];
 58 static DEFINE_SPINLOCK(cap_str_lock);
 59 static int last_cap_str;
 60 
 61 static char *gcap_string(char *s, int c)
 62 {
 63         if (c & CEPH_CAP_GSHARED)
 64                 *s++ = 's';
 65         if (c & CEPH_CAP_GEXCL)
 66                 *s++ = 'x';
 67         if (c & CEPH_CAP_GCACHE)
 68                 *s++ = 'c';
 69         if (c & CEPH_CAP_GRD)
 70                 *s++ = 'r';
 71         if (c & CEPH_CAP_GWR)
 72                 *s++ = 'w';
 73         if (c & CEPH_CAP_GBUFFER)
 74                 *s++ = 'b';
 75         if (c & CEPH_CAP_GWREXTEND)
 76                 *s++ = 'a';
 77         if (c & CEPH_CAP_GLAZYIO)
 78                 *s++ = 'l';
 79         return s;
 80 }
 81 
 82 const char *ceph_cap_string(int caps)
 83 {
 84         int i;
 85         char *s;
 86         int c;
 87 
 88         spin_lock(&cap_str_lock);
 89         i = last_cap_str++;
 90         if (last_cap_str == MAX_CAP_STR)
 91                 last_cap_str = 0;
 92         spin_unlock(&cap_str_lock);
 93 
 94         s = cap_str[i];
 95 
 96         if (caps & CEPH_CAP_PIN)
 97                 *s++ = 'p';
 98 
 99         c = (caps >> CEPH_CAP_SAUTH) & 3;
100         if (c) {
101                 *s++ = 'A';
102                 s = gcap_string(s, c);
103         }
104 
105         c = (caps >> CEPH_CAP_SLINK) & 3;
106         if (c) {
107                 *s++ = 'L';
108                 s = gcap_string(s, c);
109         }
110 
111         c = (caps >> CEPH_CAP_SXATTR) & 3;
112         if (c) {
113                 *s++ = 'X';
114                 s = gcap_string(s, c);
115         }
116 
117         c = caps >> CEPH_CAP_SFILE;
118         if (c) {
119                 *s++ = 'F';
120                 s = gcap_string(s, c);
121         }
122 
123         if (s == cap_str[i])
124                 *s++ = '-';
125         *s = 0;
126         return cap_str[i];
127 }
128 
129 void ceph_caps_init(struct ceph_mds_client *mdsc)
130 {
131         INIT_LIST_HEAD(&mdsc->caps_list);
132         spin_lock_init(&mdsc->caps_list_lock);
133 }
134 
135 void ceph_caps_finalize(struct ceph_mds_client *mdsc)
136 {
137         struct ceph_cap *cap;
138 
139         spin_lock(&mdsc->caps_list_lock);
140         while (!list_empty(&mdsc->caps_list)) {
141                 cap = list_first_entry(&mdsc->caps_list,
142                                        struct ceph_cap, caps_item);
143                 list_del(&cap->caps_item);
144                 kmem_cache_free(ceph_cap_cachep, cap);
145         }
146         mdsc->caps_total_count = 0;
147         mdsc->caps_avail_count = 0;
148         mdsc->caps_use_count = 0;
149         mdsc->caps_reserve_count = 0;
150         mdsc->caps_min_count = 0;
151         spin_unlock(&mdsc->caps_list_lock);
152 }
153 
154 void ceph_adjust_caps_max_min(struct ceph_mds_client *mdsc,
155                               struct ceph_mount_options *fsopt)
156 {
157         spin_lock(&mdsc->caps_list_lock);
158         mdsc->caps_min_count = fsopt->max_readdir;
159         if (mdsc->caps_min_count < 1024)
160                 mdsc->caps_min_count = 1024;
161         mdsc->caps_use_max = fsopt->caps_max;
162         if (mdsc->caps_use_max > 0 &&
163             mdsc->caps_use_max < mdsc->caps_min_count)
164                 mdsc->caps_use_max = mdsc->caps_min_count;
165         spin_unlock(&mdsc->caps_list_lock);
166 }
167 
168 static void __ceph_unreserve_caps(struct ceph_mds_client *mdsc, int nr_caps)
169 {
170         struct ceph_cap *cap;
171         int i;
172 
173         if (nr_caps) {
174                 BUG_ON(mdsc->caps_reserve_count < nr_caps);
175                 mdsc->caps_reserve_count -= nr_caps;
176                 if (mdsc->caps_avail_count >=
177                     mdsc->caps_reserve_count + mdsc->caps_min_count) {
178                         mdsc->caps_total_count -= nr_caps;
179                         for (i = 0; i < nr_caps; i++) {
180                                 cap = list_first_entry(&mdsc->caps_list,
181                                         struct ceph_cap, caps_item);
182                                 list_del(&cap->caps_item);
183                                 kmem_cache_free(ceph_cap_cachep, cap);
184                         }
185                 } else {
186                         mdsc->caps_avail_count += nr_caps;
187                 }
188 
189                 doutc(mdsc->fsc->client,
190                       "caps %d = %d used + %d resv + %d avail\n",
191                       mdsc->caps_total_count, mdsc->caps_use_count,
192                       mdsc->caps_reserve_count, mdsc->caps_avail_count);
193                 BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
194                                                  mdsc->caps_reserve_count +
195                                                  mdsc->caps_avail_count);
196         }
197 }
198 
199 /*
200  * Called under mdsc->mutex.
201  */
202 int ceph_reserve_caps(struct ceph_mds_client *mdsc,
203                       struct ceph_cap_reservation *ctx, int need)
204 {
205         struct ceph_client *cl = mdsc->fsc->client;
206         int i, j;
207         struct ceph_cap *cap;
208         int have;
209         int alloc = 0;
210         int max_caps;
211         int err = 0;
212         bool trimmed = false;
213         struct ceph_mds_session *s;
214         LIST_HEAD(newcaps);
215 
216         doutc(cl, "ctx=%p need=%d\n", ctx, need);
217 
218         /* first reserve any caps that are already allocated */
219         spin_lock(&mdsc->caps_list_lock);
220         if (mdsc->caps_avail_count >= need)
221                 have = need;
222         else
223                 have = mdsc->caps_avail_count;
224         mdsc->caps_avail_count -= have;
225         mdsc->caps_reserve_count += have;
226         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
227                                          mdsc->caps_reserve_count +
228                                          mdsc->caps_avail_count);
229         spin_unlock(&mdsc->caps_list_lock);
230 
231         for (i = have; i < need; ) {
232                 cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
233                 if (cap) {
234                         list_add(&cap->caps_item, &newcaps);
235                         alloc++;
236                         i++;
237                         continue;
238                 }
239 
240                 if (!trimmed) {
241                         for (j = 0; j < mdsc->max_sessions; j++) {
242                                 s = __ceph_lookup_mds_session(mdsc, j);
243                                 if (!s)
244                                         continue;
245                                 mutex_unlock(&mdsc->mutex);
246 
247                                 mutex_lock(&s->s_mutex);
248                                 max_caps = s->s_nr_caps - (need - i);
249                                 ceph_trim_caps(mdsc, s, max_caps);
250                                 mutex_unlock(&s->s_mutex);
251 
252                                 ceph_put_mds_session(s);
253                                 mutex_lock(&mdsc->mutex);
254                         }
255                         trimmed = true;
256 
257                         spin_lock(&mdsc->caps_list_lock);
258                         if (mdsc->caps_avail_count) {
259                                 int more_have;
260                                 if (mdsc->caps_avail_count >= need - i)
261                                         more_have = need - i;
262                                 else
263                                         more_have = mdsc->caps_avail_count;
264 
265                                 i += more_have;
266                                 have += more_have;
267                                 mdsc->caps_avail_count -= more_have;
268                                 mdsc->caps_reserve_count += more_have;
269 
270                         }
271                         spin_unlock(&mdsc->caps_list_lock);
272 
273                         continue;
274                 }
275 
276                 pr_warn_client(cl, "ctx=%p ENOMEM need=%d got=%d\n", ctx, need,
277                                have + alloc);
278                 err = -ENOMEM;
279                 break;
280         }
281 
282         if (!err) {
283                 BUG_ON(have + alloc != need);
284                 ctx->count = need;
285                 ctx->used = 0;
286         }
287 
288         spin_lock(&mdsc->caps_list_lock);
289         mdsc->caps_total_count += alloc;
290         mdsc->caps_reserve_count += alloc;
291         list_splice(&newcaps, &mdsc->caps_list);
292 
293         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
294                                          mdsc->caps_reserve_count +
295                                          mdsc->caps_avail_count);
296 
297         if (err)
298                 __ceph_unreserve_caps(mdsc, have + alloc);
299 
300         spin_unlock(&mdsc->caps_list_lock);
301 
302         doutc(cl, "ctx=%p %d = %d used + %d resv + %d avail\n", ctx,
303               mdsc->caps_total_count, mdsc->caps_use_count,
304               mdsc->caps_reserve_count, mdsc->caps_avail_count);
305         return err;
306 }
307 
308 void ceph_unreserve_caps(struct ceph_mds_client *mdsc,
309                          struct ceph_cap_reservation *ctx)
310 {
311         struct ceph_client *cl = mdsc->fsc->client;
312         bool reclaim = false;
313         if (!ctx->count)
314                 return;
315 
316         doutc(cl, "ctx=%p count=%d\n", ctx, ctx->count);
317         spin_lock(&mdsc->caps_list_lock);
318         __ceph_unreserve_caps(mdsc, ctx->count);
319         ctx->count = 0;
320 
321         if (mdsc->caps_use_max > 0 &&
322             mdsc->caps_use_count > mdsc->caps_use_max)
323                 reclaim = true;
324         spin_unlock(&mdsc->caps_list_lock);
325 
326         if (reclaim)
327                 ceph_reclaim_caps_nr(mdsc, ctx->used);
328 }
329 
330 struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
331                               struct ceph_cap_reservation *ctx)
332 {
333         struct ceph_client *cl = mdsc->fsc->client;
334         struct ceph_cap *cap = NULL;
335 
336         /* temporary, until we do something about cap import/export */
337         if (!ctx) {
338                 cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
339                 if (cap) {
340                         spin_lock(&mdsc->caps_list_lock);
341                         mdsc->caps_use_count++;
342                         mdsc->caps_total_count++;
343                         spin_unlock(&mdsc->caps_list_lock);
344                 } else {
345                         spin_lock(&mdsc->caps_list_lock);
346                         if (mdsc->caps_avail_count) {
347                                 BUG_ON(list_empty(&mdsc->caps_list));
348 
349                                 mdsc->caps_avail_count--;
350                                 mdsc->caps_use_count++;
351                                 cap = list_first_entry(&mdsc->caps_list,
352                                                 struct ceph_cap, caps_item);
353                                 list_del(&cap->caps_item);
354 
355                                 BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
356                                        mdsc->caps_reserve_count + mdsc->caps_avail_count);
357                         }
358                         spin_unlock(&mdsc->caps_list_lock);
359                 }
360 
361                 return cap;
362         }
363 
364         spin_lock(&mdsc->caps_list_lock);
365         doutc(cl, "ctx=%p (%d) %d = %d used + %d resv + %d avail\n", ctx,
366               ctx->count, mdsc->caps_total_count, mdsc->caps_use_count,
367               mdsc->caps_reserve_count, mdsc->caps_avail_count);
368         BUG_ON(!ctx->count);
369         BUG_ON(ctx->count > mdsc->caps_reserve_count);
370         BUG_ON(list_empty(&mdsc->caps_list));
371 
372         ctx->count--;
373         ctx->used++;
374         mdsc->caps_reserve_count--;
375         mdsc->caps_use_count++;
376 
377         cap = list_first_entry(&mdsc->caps_list, struct ceph_cap, caps_item);
378         list_del(&cap->caps_item);
379 
380         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
381                mdsc->caps_reserve_count + mdsc->caps_avail_count);
382         spin_unlock(&mdsc->caps_list_lock);
383         return cap;
384 }
385 
386 void ceph_put_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap)
387 {
388         struct ceph_client *cl = mdsc->fsc->client;
389 
390         spin_lock(&mdsc->caps_list_lock);
391         doutc(cl, "%p %d = %d used + %d resv + %d avail\n", cap,
392               mdsc->caps_total_count, mdsc->caps_use_count,
393               mdsc->caps_reserve_count, mdsc->caps_avail_count);
394         mdsc->caps_use_count--;
395         /*
396          * Keep some preallocated caps around (ceph_min_count), to
397          * avoid lots of free/alloc churn.
398          */
399         if (mdsc->caps_avail_count >= mdsc->caps_reserve_count +
400                                       mdsc->caps_min_count) {
401                 mdsc->caps_total_count--;
402                 kmem_cache_free(ceph_cap_cachep, cap);
403         } else {
404                 mdsc->caps_avail_count++;
405                 list_add(&cap->caps_item, &mdsc->caps_list);
406         }
407 
408         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
409                mdsc->caps_reserve_count + mdsc->caps_avail_count);
410         spin_unlock(&mdsc->caps_list_lock);
411 }
412 
413 void ceph_reservation_status(struct ceph_fs_client *fsc,
414                              int *total, int *avail, int *used, int *reserved,
415                              int *min)
416 {
417         struct ceph_mds_client *mdsc = fsc->mdsc;
418 
419         spin_lock(&mdsc->caps_list_lock);
420 
421         if (total)
422                 *total = mdsc->caps_total_count;
423         if (avail)
424                 *avail = mdsc->caps_avail_count;
425         if (used)
426                 *used = mdsc->caps_use_count;
427         if (reserved)
428                 *reserved = mdsc->caps_reserve_count;
429         if (min)
430                 *min = mdsc->caps_min_count;
431 
432         spin_unlock(&mdsc->caps_list_lock);
433 }
434 
435 /*
436  * Find ceph_cap for given mds, if any.
437  *
438  * Called with i_ceph_lock held.
439  */
440 struct ceph_cap *__get_cap_for_mds(struct ceph_inode_info *ci, int mds)
441 {
442         struct ceph_cap *cap;
443         struct rb_node *n = ci->i_caps.rb_node;
444 
445         while (n) {
446                 cap = rb_entry(n, struct ceph_cap, ci_node);
447                 if (mds < cap->mds)
448                         n = n->rb_left;
449                 else if (mds > cap->mds)
450                         n = n->rb_right;
451                 else
452                         return cap;
453         }
454         return NULL;
455 }
456 
457 struct ceph_cap *ceph_get_cap_for_mds(struct ceph_inode_info *ci, int mds)
458 {
459         struct ceph_cap *cap;
460 
461         spin_lock(&ci->i_ceph_lock);
462         cap = __get_cap_for_mds(ci, mds);
463         spin_unlock(&ci->i_ceph_lock);
464         return cap;
465 }
466 
467 /*
468  * Called under i_ceph_lock.
469  */
470 static void __insert_cap_node(struct ceph_inode_info *ci,
471                               struct ceph_cap *new)
472 {
473         struct rb_node **p = &ci->i_caps.rb_node;
474         struct rb_node *parent = NULL;
475         struct ceph_cap *cap = NULL;
476 
477         while (*p) {
478                 parent = *p;
479                 cap = rb_entry(parent, struct ceph_cap, ci_node);
480                 if (new->mds < cap->mds)
481                         p = &(*p)->rb_left;
482                 else if (new->mds > cap->mds)
483                         p = &(*p)->rb_right;
484                 else
485                         BUG();
486         }
487 
488         rb_link_node(&new->ci_node, parent, p);
489         rb_insert_color(&new->ci_node, &ci->i_caps);
490 }
491 
492 /*
493  * (re)set cap hold timeouts, which control the delayed release
494  * of unused caps back to the MDS.  Should be called on cap use.
495  */
496 static void __cap_set_timeouts(struct ceph_mds_client *mdsc,
497                                struct ceph_inode_info *ci)
498 {
499         struct inode *inode = &ci->netfs.inode;
500         struct ceph_mount_options *opt = mdsc->fsc->mount_options;
501 
502         ci->i_hold_caps_max = round_jiffies(jiffies +
503                                             opt->caps_wanted_delay_max * HZ);
504         doutc(mdsc->fsc->client, "%p %llx.%llx %lu\n", inode,
505               ceph_vinop(inode), ci->i_hold_caps_max - jiffies);
506 }
507 
508 /*
509  * (Re)queue cap at the end of the delayed cap release list.
510  *
511  * If I_FLUSH is set, leave the inode at the front of the list.
512  *
513  * Caller holds i_ceph_lock
514  *    -> we take mdsc->cap_delay_lock
515  */
516 static void __cap_delay_requeue(struct ceph_mds_client *mdsc,
517                                 struct ceph_inode_info *ci)
518 {
519         struct inode *inode = &ci->netfs.inode;
520 
521         doutc(mdsc->fsc->client, "%p %llx.%llx flags 0x%lx at %lu\n",
522               inode, ceph_vinop(inode), ci->i_ceph_flags,
523               ci->i_hold_caps_max);
524         if (!mdsc->stopping) {
525                 spin_lock(&mdsc->cap_delay_lock);
526                 if (!list_empty(&ci->i_cap_delay_list)) {
527                         if (ci->i_ceph_flags & CEPH_I_FLUSH)
528                                 goto no_change;
529                         list_del_init(&ci->i_cap_delay_list);
530                 }
531                 __cap_set_timeouts(mdsc, ci);
532                 list_add_tail(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
533 no_change:
534                 spin_unlock(&mdsc->cap_delay_lock);
535         }
536 }
537 
538 /*
539  * Queue an inode for immediate writeback.  Mark inode with I_FLUSH,
540  * indicating we should send a cap message to flush dirty metadata
541  * asap, and move to the front of the delayed cap list.
542  */
543 static void __cap_delay_requeue_front(struct ceph_mds_client *mdsc,
544                                       struct ceph_inode_info *ci)
545 {
546         struct inode *inode = &ci->netfs.inode;
547 
548         doutc(mdsc->fsc->client, "%p %llx.%llx\n", inode, ceph_vinop(inode));
549         spin_lock(&mdsc->cap_delay_lock);
550         ci->i_ceph_flags |= CEPH_I_FLUSH;
551         if (!list_empty(&ci->i_cap_delay_list))
552                 list_del_init(&ci->i_cap_delay_list);
553         list_add(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
554         spin_unlock(&mdsc->cap_delay_lock);
555 }
556 
557 /*
558  * Cancel delayed work on cap.
559  *
560  * Caller must hold i_ceph_lock.
561  */
562 static void __cap_delay_cancel(struct ceph_mds_client *mdsc,
563                                struct ceph_inode_info *ci)
564 {
565         struct inode *inode = &ci->netfs.inode;
566 
567         doutc(mdsc->fsc->client, "%p %llx.%llx\n", inode, ceph_vinop(inode));
568         if (list_empty(&ci->i_cap_delay_list))
569                 return;
570         spin_lock(&mdsc->cap_delay_lock);
571         list_del_init(&ci->i_cap_delay_list);
572         spin_unlock(&mdsc->cap_delay_lock);
573 }
574 
575 /* Common issue checks for add_cap, handle_cap_grant. */
576 static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
577                               unsigned issued)
578 {
579         struct inode *inode = &ci->netfs.inode;
580         struct ceph_client *cl = ceph_inode_to_client(inode);
581 
582         unsigned had = __ceph_caps_issued(ci, NULL);
583 
584         lockdep_assert_held(&ci->i_ceph_lock);
585 
586         /*
587          * Each time we receive FILE_CACHE anew, we increment
588          * i_rdcache_gen.
589          */
590         if (S_ISREG(ci->netfs.inode.i_mode) &&
591             (issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
592             (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) {
593                 ci->i_rdcache_gen++;
594         }
595 
596         /*
597          * If FILE_SHARED is newly issued, mark dir not complete. We don't
598          * know what happened to this directory while we didn't have the cap.
599          * If FILE_SHARED is being revoked, also mark dir not complete. It
600          * stops on-going cached readdir.
601          */
602         if ((issued & CEPH_CAP_FILE_SHARED) != (had & CEPH_CAP_FILE_SHARED)) {
603                 if (issued & CEPH_CAP_FILE_SHARED)
604                         atomic_inc(&ci->i_shared_gen);
605                 if (S_ISDIR(ci->netfs.inode.i_mode)) {
606                         doutc(cl, " marking %p NOT complete\n", inode);
607                         __ceph_dir_clear_complete(ci);
608                 }
609         }
610 
611         /* Wipe saved layout if we're losing DIR_CREATE caps */
612         if (S_ISDIR(ci->netfs.inode.i_mode) && (had & CEPH_CAP_DIR_CREATE) &&
613                 !(issued & CEPH_CAP_DIR_CREATE)) {
614              ceph_put_string(rcu_dereference_raw(ci->i_cached_layout.pool_ns));
615              memset(&ci->i_cached_layout, 0, sizeof(ci->i_cached_layout));
616         }
617 }
618 
619 /**
620  * change_auth_cap_ses - move inode to appropriate lists when auth caps change
621  * @ci: inode to be moved
622  * @session: new auth caps session
623  */
624 void change_auth_cap_ses(struct ceph_inode_info *ci,
625                          struct ceph_mds_session *session)
626 {
627         lockdep_assert_held(&ci->i_ceph_lock);
628 
629         if (list_empty(&ci->i_dirty_item) && list_empty(&ci->i_flushing_item))
630                 return;
631 
632         spin_lock(&session->s_mdsc->cap_dirty_lock);
633         if (!list_empty(&ci->i_dirty_item))
634                 list_move(&ci->i_dirty_item, &session->s_cap_dirty);
635         if (!list_empty(&ci->i_flushing_item))
636                 list_move_tail(&ci->i_flushing_item, &session->s_cap_flushing);
637         spin_unlock(&session->s_mdsc->cap_dirty_lock);
638 }
639 
640 /*
641  * Add a capability under the given MDS session.
642  *
643  * Caller should hold session snap_rwsem (read) and ci->i_ceph_lock
644  *
645  * @fmode is the open file mode, if we are opening a file, otherwise
646  * it is < 0.  (This is so we can atomically add the cap and add an
647  * open file reference to it.)
648  */
649 void ceph_add_cap(struct inode *inode,
650                   struct ceph_mds_session *session, u64 cap_id,
651                   unsigned issued, unsigned wanted,
652                   unsigned seq, unsigned mseq, u64 realmino, int flags,
653                   struct ceph_cap **new_cap)
654 {
655         struct ceph_mds_client *mdsc = ceph_inode_to_fs_client(inode)->mdsc;
656         struct ceph_client *cl = ceph_inode_to_client(inode);
657         struct ceph_inode_info *ci = ceph_inode(inode);
658         struct ceph_cap *cap;
659         int mds = session->s_mds;
660         int actual_wanted;
661         u32 gen;
662 
663         lockdep_assert_held(&ci->i_ceph_lock);
664 
665         doutc(cl, "%p %llx.%llx mds%d cap %llx %s seq %d\n", inode,
666               ceph_vinop(inode), session->s_mds, cap_id,
667               ceph_cap_string(issued), seq);
668 
669         gen = atomic_read(&session->s_cap_gen);
670 
671         cap = __get_cap_for_mds(ci, mds);
672         if (!cap) {
673                 cap = *new_cap;
674                 *new_cap = NULL;
675 
676                 cap->issued = 0;
677                 cap->implemented = 0;
678                 cap->mds = mds;
679                 cap->mds_wanted = 0;
680                 cap->mseq = 0;
681 
682                 cap->ci = ci;
683                 __insert_cap_node(ci, cap);
684 
685                 /* add to session cap list */
686                 cap->session = session;
687                 spin_lock(&session->s_cap_lock);
688                 list_add_tail(&cap->session_caps, &session->s_caps);
689                 session->s_nr_caps++;
690                 atomic64_inc(&mdsc->metric.total_caps);
691                 spin_unlock(&session->s_cap_lock);
692         } else {
693                 spin_lock(&session->s_cap_lock);
694                 list_move_tail(&cap->session_caps, &session->s_caps);
695                 spin_unlock(&session->s_cap_lock);
696 
697                 if (cap->cap_gen < gen)
698                         cap->issued = cap->implemented = CEPH_CAP_PIN;
699 
700                 /*
701                  * auth mds of the inode changed. we received the cap export
702                  * message, but still haven't received the cap import message.
703                  * handle_cap_export() updated the new auth MDS' cap.
704                  *
705                  * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing
706                  * a message that was send before the cap import message. So
707                  * don't remove caps.
708                  */
709                 if (ceph_seq_cmp(seq, cap->seq) <= 0) {
710                         WARN_ON(cap != ci->i_auth_cap);
711                         WARN_ON(cap->cap_id != cap_id);
712                         seq = cap->seq;
713                         mseq = cap->mseq;
714                         issued |= cap->issued;
715                         flags |= CEPH_CAP_FLAG_AUTH;
716                 }
717         }
718 
719         if (!ci->i_snap_realm ||
720             ((flags & CEPH_CAP_FLAG_AUTH) &&
721              realmino != (u64)-1 && ci->i_snap_realm->ino != realmino)) {
722                 /*
723                  * add this inode to the appropriate snap realm
724                  */
725                 struct ceph_snap_realm *realm = ceph_lookup_snap_realm(mdsc,
726                                                                realmino);
727                 if (realm)
728                         ceph_change_snap_realm(inode, realm);
729                 else
730                         WARN(1, "%s: couldn't find snap realm 0x%llx (ino 0x%llx oldrealm 0x%llx)\n",
731                              __func__, realmino, ci->i_vino.ino,
732                              ci->i_snap_realm ? ci->i_snap_realm->ino : 0);
733         }
734 
735         __check_cap_issue(ci, cap, issued);
736 
737         /*
738          * If we are issued caps we don't want, or the mds' wanted
739          * value appears to be off, queue a check so we'll release
740          * later and/or update the mds wanted value.
741          */
742         actual_wanted = __ceph_caps_wanted(ci);
743         if ((wanted & ~actual_wanted) ||
744             (issued & ~actual_wanted & CEPH_CAP_ANY_WR)) {
745                 doutc(cl, "issued %s, mds wanted %s, actual %s, queueing\n",
746                       ceph_cap_string(issued), ceph_cap_string(wanted),
747                       ceph_cap_string(actual_wanted));
748                 __cap_delay_requeue(mdsc, ci);
749         }
750 
751         if (flags & CEPH_CAP_FLAG_AUTH) {
752                 if (!ci->i_auth_cap ||
753                     ceph_seq_cmp(ci->i_auth_cap->mseq, mseq) < 0) {
754                         if (ci->i_auth_cap &&
755                             ci->i_auth_cap->session != cap->session)
756                                 change_auth_cap_ses(ci, cap->session);
757                         ci->i_auth_cap = cap;
758                         cap->mds_wanted = wanted;
759                 }
760         } else {
761                 WARN_ON(ci->i_auth_cap == cap);
762         }
763 
764         doutc(cl, "inode %p %llx.%llx cap %p %s now %s seq %d mds%d\n",
765               inode, ceph_vinop(inode), cap, ceph_cap_string(issued),
766               ceph_cap_string(issued|cap->issued), seq, mds);
767         cap->cap_id = cap_id;
768         cap->issued = issued;
769         cap->implemented |= issued;
770         if (ceph_seq_cmp(mseq, cap->mseq) > 0)
771                 cap->mds_wanted = wanted;
772         else
773                 cap->mds_wanted |= wanted;
774         cap->seq = seq;
775         cap->issue_seq = seq;
776         cap->mseq = mseq;
777         cap->cap_gen = gen;
778         wake_up_all(&ci->i_cap_wq);
779 }
780 
781 /*
782  * Return true if cap has not timed out and belongs to the current
783  * generation of the MDS session (i.e. has not gone 'stale' due to
784  * us losing touch with the mds).
785  */
786 static int __cap_is_valid(struct ceph_cap *cap)
787 {
788         struct inode *inode = &cap->ci->netfs.inode;
789         struct ceph_client *cl = cap->session->s_mdsc->fsc->client;
790         unsigned long ttl;
791         u32 gen;
792 
793         gen = atomic_read(&cap->session->s_cap_gen);
794         ttl = cap->session->s_cap_ttl;
795 
796         if (cap->cap_gen < gen || time_after_eq(jiffies, ttl)) {
797                 doutc(cl, "%p %llx.%llx cap %p issued %s but STALE (gen %u vs %u)\n",
798                       inode, ceph_vinop(inode), cap,
799                       ceph_cap_string(cap->issued), cap->cap_gen, gen);
800                 return 0;
801         }
802 
803         return 1;
804 }
805 
806 /*
807  * Return set of valid cap bits issued to us.  Note that caps time
808  * out, and may be invalidated in bulk if the client session times out
809  * and session->s_cap_gen is bumped.
810  */
811 int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented)
812 {
813         struct inode *inode = &ci->netfs.inode;
814         struct ceph_client *cl = ceph_inode_to_client(inode);
815         int have = ci->i_snap_caps;
816         struct ceph_cap *cap;
817         struct rb_node *p;
818 
819         if (implemented)
820                 *implemented = 0;
821         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
822                 cap = rb_entry(p, struct ceph_cap, ci_node);
823                 if (!__cap_is_valid(cap))
824                         continue;
825                 doutc(cl, "%p %llx.%llx cap %p issued %s\n", inode,
826                       ceph_vinop(inode), cap, ceph_cap_string(cap->issued));
827                 have |= cap->issued;
828                 if (implemented)
829                         *implemented |= cap->implemented;
830         }
831         /*
832          * exclude caps issued by non-auth MDS, but are been revoking
833          * by the auth MDS. The non-auth MDS should be revoking/exporting
834          * these caps, but the message is delayed.
835          */
836         if (ci->i_auth_cap) {
837                 cap = ci->i_auth_cap;
838                 have &= ~cap->implemented | cap->issued;
839         }
840         return have;
841 }
842 
843 /*
844  * Get cap bits issued by caps other than @ocap
845  */
846 int __ceph_caps_issued_other(struct ceph_inode_info *ci, struct ceph_cap *ocap)
847 {
848         int have = ci->i_snap_caps;
849         struct ceph_cap *cap;
850         struct rb_node *p;
851 
852         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
853                 cap = rb_entry(p, struct ceph_cap, ci_node);
854                 if (cap == ocap)
855                         continue;
856                 if (!__cap_is_valid(cap))
857                         continue;
858                 have |= cap->issued;
859         }
860         return have;
861 }
862 
863 /*
864  * Move a cap to the end of the LRU (oldest caps at list head, newest
865  * at list tail).
866  */
867 static void __touch_cap(struct ceph_cap *cap)
868 {
869         struct inode *inode = &cap->ci->netfs.inode;
870         struct ceph_mds_session *s = cap->session;
871         struct ceph_client *cl = s->s_mdsc->fsc->client;
872 
873         spin_lock(&s->s_cap_lock);
874         if (!s->s_cap_iterator) {
875                 doutc(cl, "%p %llx.%llx cap %p mds%d\n", inode,
876                       ceph_vinop(inode), cap, s->s_mds);
877                 list_move_tail(&cap->session_caps, &s->s_caps);
878         } else {
879                 doutc(cl, "%p %llx.%llx cap %p mds%d NOP, iterating over caps\n",
880                       inode, ceph_vinop(inode), cap, s->s_mds);
881         }
882         spin_unlock(&s->s_cap_lock);
883 }
884 
885 /*
886  * Check if we hold the given mask.  If so, move the cap(s) to the
887  * front of their respective LRUs.  (This is the preferred way for
888  * callers to check for caps they want.)
889  */
890 int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
891 {
892         struct inode *inode = &ci->netfs.inode;
893         struct ceph_client *cl = ceph_inode_to_client(inode);
894         struct ceph_cap *cap;
895         struct rb_node *p;
896         int have = ci->i_snap_caps;
897 
898         if ((have & mask) == mask) {
899                 doutc(cl, "mask %p %llx.%llx snap issued %s (mask %s)\n",
900                       inode, ceph_vinop(inode), ceph_cap_string(have),
901                       ceph_cap_string(mask));
902                 return 1;
903         }
904 
905         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
906                 cap = rb_entry(p, struct ceph_cap, ci_node);
907                 if (!__cap_is_valid(cap))
908                         continue;
909                 if ((cap->issued & mask) == mask) {
910                         doutc(cl, "mask %p %llx.%llx cap %p issued %s (mask %s)\n",
911                               inode, ceph_vinop(inode), cap,
912                               ceph_cap_string(cap->issued),
913                               ceph_cap_string(mask));
914                         if (touch)
915                                 __touch_cap(cap);
916                         return 1;
917                 }
918 
919                 /* does a combination of caps satisfy mask? */
920                 have |= cap->issued;
921                 if ((have & mask) == mask) {
922                         doutc(cl, "mask %p %llx.%llx combo issued %s (mask %s)\n",
923                               inode, ceph_vinop(inode),
924                               ceph_cap_string(cap->issued),
925                               ceph_cap_string(mask));
926                         if (touch) {
927                                 struct rb_node *q;
928 
929                                 /* touch this + preceding caps */
930                                 __touch_cap(cap);
931                                 for (q = rb_first(&ci->i_caps); q != p;
932                                      q = rb_next(q)) {
933                                         cap = rb_entry(q, struct ceph_cap,
934                                                        ci_node);
935                                         if (!__cap_is_valid(cap))
936                                                 continue;
937                                         if (cap->issued & mask)
938                                                 __touch_cap(cap);
939                                 }
940                         }
941                         return 1;
942                 }
943         }
944 
945         return 0;
946 }
947 
948 int __ceph_caps_issued_mask_metric(struct ceph_inode_info *ci, int mask,
949                                    int touch)
950 {
951         struct ceph_fs_client *fsc = ceph_sb_to_fs_client(ci->netfs.inode.i_sb);
952         int r;
953 
954         r = __ceph_caps_issued_mask(ci, mask, touch);
955         if (r)
956                 ceph_update_cap_hit(&fsc->mdsc->metric);
957         else
958                 ceph_update_cap_mis(&fsc->mdsc->metric);
959         return r;
960 }
961 
962 /*
963  * Return true if mask caps are currently being revoked by an MDS.
964  */
965 int __ceph_caps_revoking_other(struct ceph_inode_info *ci,
966                                struct ceph_cap *ocap, int mask)
967 {
968         struct ceph_cap *cap;
969         struct rb_node *p;
970 
971         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
972                 cap = rb_entry(p, struct ceph_cap, ci_node);
973                 if (cap != ocap &&
974                     (cap->implemented & ~cap->issued & mask))
975                         return 1;
976         }
977         return 0;
978 }
979 
980 int ceph_caps_revoking(struct ceph_inode_info *ci, int mask)
981 {
982         struct inode *inode = &ci->netfs.inode;
983         struct ceph_client *cl = ceph_inode_to_client(inode);
984         int ret;
985 
986         spin_lock(&ci->i_ceph_lock);
987         ret = __ceph_caps_revoking_other(ci, NULL, mask);
988         spin_unlock(&ci->i_ceph_lock);
989         doutc(cl, "%p %llx.%llx %s = %d\n", inode, ceph_vinop(inode),
990               ceph_cap_string(mask), ret);
991         return ret;
992 }
993 
994 int __ceph_caps_used(struct ceph_inode_info *ci)
995 {
996         int used = 0;
997         if (ci->i_pin_ref)
998                 used |= CEPH_CAP_PIN;
999         if (ci->i_rd_ref)
1000                 used |= CEPH_CAP_FILE_RD;
1001         if (ci->i_rdcache_ref ||
1002             (S_ISREG(ci->netfs.inode.i_mode) &&
1003              ci->netfs.inode.i_data.nrpages))
1004                 used |= CEPH_CAP_FILE_CACHE;
1005         if (ci->i_wr_ref)
1006                 used |= CEPH_CAP_FILE_WR;
1007         if (ci->i_wb_ref || ci->i_wrbuffer_ref)
1008                 used |= CEPH_CAP_FILE_BUFFER;
1009         if (ci->i_fx_ref)
1010                 used |= CEPH_CAP_FILE_EXCL;
1011         return used;
1012 }
1013 
1014 #define FMODE_WAIT_BIAS 1000
1015 
1016 /*
1017  * wanted, by virtue of open file modes
1018  */
1019 int __ceph_caps_file_wanted(struct ceph_inode_info *ci)
1020 {
1021         const int PIN_SHIFT = ffs(CEPH_FILE_MODE_PIN);
1022         const int RD_SHIFT = ffs(CEPH_FILE_MODE_RD);
1023         const int WR_SHIFT = ffs(CEPH_FILE_MODE_WR);
1024         const int LAZY_SHIFT = ffs(CEPH_FILE_MODE_LAZY);
1025         struct ceph_mount_options *opt =
1026                 ceph_inode_to_fs_client(&ci->netfs.inode)->mount_options;
1027         unsigned long used_cutoff = jiffies - opt->caps_wanted_delay_max * HZ;
1028         unsigned long idle_cutoff = jiffies - opt->caps_wanted_delay_min * HZ;
1029 
1030         if (S_ISDIR(ci->netfs.inode.i_mode)) {
1031                 int want = 0;
1032 
1033                 /* use used_cutoff here, to keep dir's wanted caps longer */
1034                 if (ci->i_nr_by_mode[RD_SHIFT] > 0 ||
1035                     time_after(ci->i_last_rd, used_cutoff))
1036                         want |= CEPH_CAP_ANY_SHARED;
1037 
1038                 if (ci->i_nr_by_mode[WR_SHIFT] > 0 ||
1039                     time_after(ci->i_last_wr, used_cutoff)) {
1040                         want |= CEPH_CAP_ANY_SHARED | CEPH_CAP_FILE_EXCL;
1041                         if (opt->flags & CEPH_MOUNT_OPT_ASYNC_DIROPS)
1042                                 want |= CEPH_CAP_ANY_DIR_OPS;
1043                 }
1044 
1045                 if (want || ci->i_nr_by_mode[PIN_SHIFT] > 0)
1046                         want |= CEPH_CAP_PIN;
1047 
1048                 return want;
1049         } else {
1050                 int bits = 0;
1051 
1052                 if (ci->i_nr_by_mode[RD_SHIFT] > 0) {
1053                         if (ci->i_nr_by_mode[RD_SHIFT] >= FMODE_WAIT_BIAS ||
1054                             time_after(ci->i_last_rd, used_cutoff))
1055                                 bits |= 1 << RD_SHIFT;
1056                 } else if (time_after(ci->i_last_rd, idle_cutoff)) {
1057                         bits |= 1 << RD_SHIFT;
1058                 }
1059 
1060                 if (ci->i_nr_by_mode[WR_SHIFT] > 0) {
1061                         if (ci->i_nr_by_mode[WR_SHIFT] >= FMODE_WAIT_BIAS ||
1062                             time_after(ci->i_last_wr, used_cutoff))
1063                                 bits |= 1 << WR_SHIFT;
1064                 } else if (time_after(ci->i_last_wr, idle_cutoff)) {
1065                         bits |= 1 << WR_SHIFT;
1066                 }
1067 
1068                 /* check lazyio only when read/write is wanted */
1069                 if ((bits & (CEPH_FILE_MODE_RDWR << 1)) &&
1070                     ci->i_nr_by_mode[LAZY_SHIFT] > 0)
1071                         bits |= 1 << LAZY_SHIFT;
1072 
1073                 return bits ? ceph_caps_for_mode(bits >> 1) : 0;
1074         }
1075 }
1076 
1077 /*
1078  * wanted, by virtue of open file modes AND cap refs (buffered/cached data)
1079  */
1080 int __ceph_caps_wanted(struct ceph_inode_info *ci)
1081 {
1082         int w = __ceph_caps_file_wanted(ci) | __ceph_caps_used(ci);
1083         if (S_ISDIR(ci->netfs.inode.i_mode)) {
1084                 /* we want EXCL if holding caps of dir ops */
1085                 if (w & CEPH_CAP_ANY_DIR_OPS)
1086                         w |= CEPH_CAP_FILE_EXCL;
1087         } else {
1088                 /* we want EXCL if dirty data */
1089                 if (w & CEPH_CAP_FILE_BUFFER)
1090                         w |= CEPH_CAP_FILE_EXCL;
1091         }
1092         return w;
1093 }
1094 
1095 /*
1096  * Return caps we have registered with the MDS(s) as 'wanted'.
1097  */
1098 int __ceph_caps_mds_wanted(struct ceph_inode_info *ci, bool check)
1099 {
1100         struct ceph_cap *cap;
1101         struct rb_node *p;
1102         int mds_wanted = 0;
1103 
1104         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
1105                 cap = rb_entry(p, struct ceph_cap, ci_node);
1106                 if (check && !__cap_is_valid(cap))
1107                         continue;
1108                 if (cap == ci->i_auth_cap)
1109                         mds_wanted |= cap->mds_wanted;
1110                 else
1111                         mds_wanted |= (cap->mds_wanted & ~CEPH_CAP_ANY_FILE_WR);
1112         }
1113         return mds_wanted;
1114 }
1115 
1116 int ceph_is_any_caps(struct inode *inode)
1117 {
1118         struct ceph_inode_info *ci = ceph_inode(inode);
1119         int ret;
1120 
1121         spin_lock(&ci->i_ceph_lock);
1122         ret = __ceph_is_any_real_caps(ci);
1123         spin_unlock(&ci->i_ceph_lock);
1124 
1125         return ret;
1126 }
1127 
1128 /*
1129  * Remove a cap.  Take steps to deal with a racing iterate_session_caps.
1130  *
1131  * caller should hold i_ceph_lock.
1132  * caller will not hold session s_mutex if called from destroy_inode.
1133  */
1134 void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release)
1135 {
1136         struct ceph_mds_session *session = cap->session;
1137         struct ceph_client *cl = session->s_mdsc->fsc->client;
1138         struct ceph_inode_info *ci = cap->ci;
1139         struct inode *inode = &ci->netfs.inode;
1140         struct ceph_mds_client *mdsc;
1141         int removed = 0;
1142 
1143         /* 'ci' being NULL means the remove have already occurred */
1144         if (!ci) {
1145                 doutc(cl, "inode is NULL\n");
1146                 return;
1147         }
1148 
1149         lockdep_assert_held(&ci->i_ceph_lock);
1150 
1151         doutc(cl, "%p from %p %llx.%llx\n", cap, inode, ceph_vinop(inode));
1152 
1153         mdsc = ceph_inode_to_fs_client(&ci->netfs.inode)->mdsc;
1154 
1155         /* remove from inode's cap rbtree, and clear auth cap */
1156         rb_erase(&cap->ci_node, &ci->i_caps);
1157         if (ci->i_auth_cap == cap)
1158                 ci->i_auth_cap = NULL;
1159 
1160         /* remove from session list */
1161         spin_lock(&session->s_cap_lock);
1162         if (session->s_cap_iterator == cap) {
1163                 /* not yet, we are iterating over this very cap */
1164                 doutc(cl, "delaying %p removal from session %p\n", cap,
1165                       cap->session);
1166         } else {
1167                 list_del_init(&cap->session_caps);
1168                 session->s_nr_caps--;
1169                 atomic64_dec(&mdsc->metric.total_caps);
1170                 cap->session = NULL;
1171                 removed = 1;
1172         }
1173         /* protect backpointer with s_cap_lock: see iterate_session_caps */
1174         cap->ci = NULL;
1175 
1176         /*
1177          * s_cap_reconnect is protected by s_cap_lock. no one changes
1178          * s_cap_gen while session is in the reconnect state.
1179          */
1180         if (queue_release &&
1181             (!session->s_cap_reconnect ||
1182              cap->cap_gen == atomic_read(&session->s_cap_gen))) {
1183                 cap->queue_release = 1;
1184                 if (removed) {
1185                         __ceph_queue_cap_release(session, cap);
1186                         removed = 0;
1187                 }
1188         } else {
1189                 cap->queue_release = 0;
1190         }
1191         cap->cap_ino = ci->i_vino.ino;
1192 
1193         spin_unlock(&session->s_cap_lock);
1194 
1195         if (removed)
1196                 ceph_put_cap(mdsc, cap);
1197 
1198         if (!__ceph_is_any_real_caps(ci)) {
1199                 /* when reconnect denied, we remove session caps forcibly,
1200                  * i_wr_ref can be non-zero. If there are ongoing write,
1201                  * keep i_snap_realm.
1202                  */
1203                 if (ci->i_wr_ref == 0 && ci->i_snap_realm)
1204                         ceph_change_snap_realm(&ci->netfs.inode, NULL);
1205 
1206                 __cap_delay_cancel(mdsc, ci);
1207         }
1208 }
1209 
1210 void ceph_remove_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
1211                      bool queue_release)
1212 {
1213         struct ceph_inode_info *ci = cap->ci;
1214         struct ceph_fs_client *fsc;
1215 
1216         /* 'ci' being NULL means the remove have already occurred */
1217         if (!ci) {
1218                 doutc(mdsc->fsc->client, "inode is NULL\n");
1219                 return;
1220         }
1221 
1222         lockdep_assert_held(&ci->i_ceph_lock);
1223 
1224         fsc = ceph_inode_to_fs_client(&ci->netfs.inode);
1225         WARN_ON_ONCE(ci->i_auth_cap == cap &&
1226                      !list_empty(&ci->i_dirty_item) &&
1227                      !fsc->blocklisted &&
1228                      !ceph_inode_is_shutdown(&ci->netfs.inode));
1229 
1230         __ceph_remove_cap(cap, queue_release);
1231 }
1232 
1233 struct cap_msg_args {
1234         struct ceph_mds_session *session;
1235         u64                     ino, cid, follows;
1236         u64                     flush_tid, oldest_flush_tid, size, max_size;
1237         u64                     xattr_version;
1238         u64                     change_attr;
1239         struct ceph_buffer      *xattr_buf;
1240         struct ceph_buffer      *old_xattr_buf;
1241         struct timespec64       atime, mtime, ctime, btime;
1242         int                     op, caps, wanted, dirty;
1243         u32                     seq, issue_seq, mseq, time_warp_seq;
1244         u32                     flags;
1245         kuid_t                  uid;
1246         kgid_t                  gid;
1247         umode_t                 mode;
1248         bool                    inline_data;
1249         bool                    wake;
1250         bool                    encrypted;
1251         u32                     fscrypt_auth_len;
1252         u8                      fscrypt_auth[sizeof(struct ceph_fscrypt_auth)]; // for context
1253 };
1254 
1255 /* Marshal up the cap msg to the MDS */
1256 static void encode_cap_msg(struct ceph_msg *msg, struct cap_msg_args *arg)
1257 {
1258         struct ceph_mds_caps *fc;
1259         void *p;
1260         struct ceph_mds_client *mdsc = arg->session->s_mdsc;
1261         struct ceph_osd_client *osdc = &mdsc->fsc->client->osdc;
1262 
1263         doutc(mdsc->fsc->client,
1264               "%s %llx %llx caps %s wanted %s dirty %s seq %u/%u"
1265               " tid %llu/%llu mseq %u follows %lld size %llu/%llu"
1266               " xattr_ver %llu xattr_len %d\n",
1267               ceph_cap_op_name(arg->op), arg->cid, arg->ino,
1268               ceph_cap_string(arg->caps), ceph_cap_string(arg->wanted),
1269               ceph_cap_string(arg->dirty), arg->seq, arg->issue_seq,
1270               arg->flush_tid, arg->oldest_flush_tid, arg->mseq, arg->follows,
1271               arg->size, arg->max_size, arg->xattr_version,
1272               arg->xattr_buf ? (int)arg->xattr_buf->vec.iov_len : 0);
1273 
1274         msg->hdr.version = cpu_to_le16(12);
1275         msg->hdr.tid = cpu_to_le64(arg->flush_tid);
1276 
1277         fc = msg->front.iov_base;
1278         memset(fc, 0, sizeof(*fc));
1279 
1280         fc->cap_id = cpu_to_le64(arg->cid);
1281         fc->op = cpu_to_le32(arg->op);
1282         fc->seq = cpu_to_le32(arg->seq);
1283         fc->issue_seq = cpu_to_le32(arg->issue_seq);
1284         fc->migrate_seq = cpu_to_le32(arg->mseq);
1285         fc->caps = cpu_to_le32(arg->caps);
1286         fc->wanted = cpu_to_le32(arg->wanted);
1287         fc->dirty = cpu_to_le32(arg->dirty);
1288         fc->ino = cpu_to_le64(arg->ino);
1289         fc->snap_follows = cpu_to_le64(arg->follows);
1290 
1291 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
1292         if (arg->encrypted)
1293                 fc->size = cpu_to_le64(round_up(arg->size,
1294                                                 CEPH_FSCRYPT_BLOCK_SIZE));
1295         else
1296 #endif
1297                 fc->size = cpu_to_le64(arg->size);
1298         fc->max_size = cpu_to_le64(arg->max_size);
1299         ceph_encode_timespec64(&fc->mtime, &arg->mtime);
1300         ceph_encode_timespec64(&fc->atime, &arg->atime);
1301         ceph_encode_timespec64(&fc->ctime, &arg->ctime);
1302         fc->time_warp_seq = cpu_to_le32(arg->time_warp_seq);
1303 
1304         fc->uid = cpu_to_le32(from_kuid(&init_user_ns, arg->uid));
1305         fc->gid = cpu_to_le32(from_kgid(&init_user_ns, arg->gid));
1306         fc->mode = cpu_to_le32(arg->mode);
1307 
1308         fc->xattr_version = cpu_to_le64(arg->xattr_version);
1309         if (arg->xattr_buf) {
1310                 msg->middle = ceph_buffer_get(arg->xattr_buf);
1311                 fc->xattr_len = cpu_to_le32(arg->xattr_buf->vec.iov_len);
1312                 msg->hdr.middle_len = cpu_to_le32(arg->xattr_buf->vec.iov_len);
1313         }
1314 
1315         p = fc + 1;
1316         /* flock buffer size (version 2) */
1317         ceph_encode_32(&p, 0);
1318         /* inline version (version 4) */
1319         ceph_encode_64(&p, arg->inline_data ? 0 : CEPH_INLINE_NONE);
1320         /* inline data size */
1321         ceph_encode_32(&p, 0);
1322         /*
1323          * osd_epoch_barrier (version 5)
1324          * The epoch_barrier is protected osdc->lock, so READ_ONCE here in
1325          * case it was recently changed
1326          */
1327         ceph_encode_32(&p, READ_ONCE(osdc->epoch_barrier));
1328         /* oldest_flush_tid (version 6) */
1329         ceph_encode_64(&p, arg->oldest_flush_tid);
1330 
1331         /*
1332          * caller_uid/caller_gid (version 7)
1333          *
1334          * Currently, we don't properly track which caller dirtied the caps
1335          * last, and force a flush of them when there is a conflict. For now,
1336          * just set this to 0:0, to emulate how the MDS has worked up to now.
1337          */
1338         ceph_encode_32(&p, 0);
1339         ceph_encode_32(&p, 0);
1340 
1341         /* pool namespace (version 8) (mds always ignores this) */
1342         ceph_encode_32(&p, 0);
1343 
1344         /* btime and change_attr (version 9) */
1345         ceph_encode_timespec64(p, &arg->btime);
1346         p += sizeof(struct ceph_timespec);
1347         ceph_encode_64(&p, arg->change_attr);
1348 
1349         /* Advisory flags (version 10) */
1350         ceph_encode_32(&p, arg->flags);
1351 
1352         /* dirstats (version 11) - these are r/o on the client */
1353         ceph_encode_64(&p, 0);
1354         ceph_encode_64(&p, 0);
1355 
1356 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
1357         /*
1358          * fscrypt_auth and fscrypt_file (version 12)
1359          *
1360          * fscrypt_auth holds the crypto context (if any). fscrypt_file
1361          * tracks the real i_size as an __le64 field (and we use a rounded-up
1362          * i_size in the traditional size field).
1363          */
1364         ceph_encode_32(&p, arg->fscrypt_auth_len);
1365         ceph_encode_copy(&p, arg->fscrypt_auth, arg->fscrypt_auth_len);
1366         ceph_encode_32(&p, sizeof(__le64));
1367         ceph_encode_64(&p, arg->size);
1368 #else /* CONFIG_FS_ENCRYPTION */
1369         ceph_encode_32(&p, 0);
1370         ceph_encode_32(&p, 0);
1371 #endif /* CONFIG_FS_ENCRYPTION */
1372 }
1373 
1374 /*
1375  * Queue cap releases when an inode is dropped from our cache.
1376  */
1377 void __ceph_remove_caps(struct ceph_inode_info *ci)
1378 {
1379         struct inode *inode = &ci->netfs.inode;
1380         struct ceph_mds_client *mdsc = ceph_inode_to_fs_client(inode)->mdsc;
1381         struct rb_node *p;
1382 
1383         /* lock i_ceph_lock, because ceph_d_revalidate(..., LOOKUP_RCU)
1384          * may call __ceph_caps_issued_mask() on a freeing inode. */
1385         spin_lock(&ci->i_ceph_lock);
1386         p = rb_first(&ci->i_caps);
1387         while (p) {
1388                 struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
1389                 p = rb_next(p);
1390                 ceph_remove_cap(mdsc, cap, true);
1391         }
1392         spin_unlock(&ci->i_ceph_lock);
1393 }
1394 
1395 /*
1396  * Prepare to send a cap message to an MDS. Update the cap state, and populate
1397  * the arg struct with the parameters that will need to be sent. This should
1398  * be done under the i_ceph_lock to guard against changes to cap state.
1399  *
1400  * Make note of max_size reported/requested from mds, revoked caps
1401  * that have now been implemented.
1402  */
1403 static void __prep_cap(struct cap_msg_args *arg, struct ceph_cap *cap,
1404                        int op, int flags, int used, int want, int retain,
1405                        int flushing, u64 flush_tid, u64 oldest_flush_tid)
1406 {
1407         struct ceph_inode_info *ci = cap->ci;
1408         struct inode *inode = &ci->netfs.inode;
1409         struct ceph_client *cl = ceph_inode_to_client(inode);
1410         int held, revoking;
1411 
1412         lockdep_assert_held(&ci->i_ceph_lock);
1413 
1414         held = cap->issued | cap->implemented;
1415         revoking = cap->implemented & ~cap->issued;
1416         retain &= ~revoking;
1417 
1418         doutc(cl, "%p %llx.%llx cap %p session %p %s -> %s (revoking %s)\n",
1419               inode, ceph_vinop(inode), cap, cap->session,
1420               ceph_cap_string(held), ceph_cap_string(held & retain),
1421               ceph_cap_string(revoking));
1422         BUG_ON((retain & CEPH_CAP_PIN) == 0);
1423 
1424         ci->i_ceph_flags &= ~CEPH_I_FLUSH;
1425 
1426         cap->issued &= retain;  /* drop bits we don't want */
1427         /*
1428          * Wake up any waiters on wanted -> needed transition. This is due to
1429          * the weird transition from buffered to sync IO... we need to flush
1430          * dirty pages _before_ allowing sync writes to avoid reordering.
1431          */
1432         arg->wake = cap->implemented & ~cap->issued;
1433         cap->implemented &= cap->issued | used;
1434         cap->mds_wanted = want;
1435 
1436         arg->session = cap->session;
1437         arg->ino = ceph_vino(inode).ino;
1438         arg->cid = cap->cap_id;
1439         arg->follows = flushing ? ci->i_head_snapc->seq : 0;
1440         arg->flush_tid = flush_tid;
1441         arg->oldest_flush_tid = oldest_flush_tid;
1442         arg->size = i_size_read(inode);
1443         ci->i_reported_size = arg->size;
1444         arg->max_size = ci->i_wanted_max_size;
1445         if (cap == ci->i_auth_cap) {
1446                 if (want & CEPH_CAP_ANY_FILE_WR)
1447                         ci->i_requested_max_size = arg->max_size;
1448                 else
1449                         ci->i_requested_max_size = 0;
1450         }
1451 
1452         if (flushing & CEPH_CAP_XATTR_EXCL) {
1453                 arg->old_xattr_buf = __ceph_build_xattrs_blob(ci);
1454                 arg->xattr_version = ci->i_xattrs.version;
1455                 arg->xattr_buf = ceph_buffer_get(ci->i_xattrs.blob);
1456         } else {
1457                 arg->xattr_buf = NULL;
1458                 arg->old_xattr_buf = NULL;
1459         }
1460 
1461         arg->mtime = inode_get_mtime(inode);
1462         arg->atime = inode_get_atime(inode);
1463         arg->ctime = inode_get_ctime(inode);
1464         arg->btime = ci->i_btime;
1465         arg->change_attr = inode_peek_iversion_raw(inode);
1466 
1467         arg->op = op;
1468         arg->caps = cap->implemented;
1469         arg->wanted = want;
1470         arg->dirty = flushing;
1471 
1472         arg->seq = cap->seq;
1473         arg->issue_seq = cap->issue_seq;
1474         arg->mseq = cap->mseq;
1475         arg->time_warp_seq = ci->i_time_warp_seq;
1476 
1477         arg->uid = inode->i_uid;
1478         arg->gid = inode->i_gid;
1479         arg->mode = inode->i_mode;
1480 
1481         arg->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
1482         if (!(flags & CEPH_CLIENT_CAPS_PENDING_CAPSNAP) &&
1483             !list_empty(&ci->i_cap_snaps)) {
1484                 struct ceph_cap_snap *capsnap;
1485                 list_for_each_entry_reverse(capsnap, &ci->i_cap_snaps, ci_item) {
1486                         if (capsnap->cap_flush.tid)
1487                                 break;
1488                         if (capsnap->need_flush) {
1489                                 flags |= CEPH_CLIENT_CAPS_PENDING_CAPSNAP;
1490                                 break;
1491                         }
1492                 }
1493         }
1494         arg->flags = flags;
1495         arg->encrypted = IS_ENCRYPTED(inode);
1496 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
1497         if (ci->fscrypt_auth_len &&
1498             WARN_ON_ONCE(ci->fscrypt_auth_len > sizeof(struct ceph_fscrypt_auth))) {
1499                 /* Don't set this if it's too big */
1500                 arg->fscrypt_auth_len = 0;
1501         } else {
1502                 arg->fscrypt_auth_len = ci->fscrypt_auth_len;
1503                 memcpy(arg->fscrypt_auth, ci->fscrypt_auth,
1504                        min_t(size_t, ci->fscrypt_auth_len,
1505                              sizeof(arg->fscrypt_auth)));
1506         }
1507 #endif /* CONFIG_FS_ENCRYPTION */
1508 }
1509 
1510 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
1511 #define CAP_MSG_FIXED_FIELDS (sizeof(struct ceph_mds_caps) + \
1512                       4 + 8 + 4 + 4 + 8 + 4 + 4 + 4 + 8 + 8 + 4 + 8 + 8 + 4 + 4 + 8)
1513 
1514 static inline int cap_msg_size(struct cap_msg_args *arg)
1515 {
1516         return CAP_MSG_FIXED_FIELDS + arg->fscrypt_auth_len;
1517 }
1518 #else
1519 #define CAP_MSG_FIXED_FIELDS (sizeof(struct ceph_mds_caps) + \
1520                       4 + 8 + 4 + 4 + 8 + 4 + 4 + 4 + 8 + 8 + 4 + 8 + 8 + 4 + 4)
1521 
1522 static inline int cap_msg_size(struct cap_msg_args *arg)
1523 {
1524         return CAP_MSG_FIXED_FIELDS;
1525 }
1526 #endif /* CONFIG_FS_ENCRYPTION */
1527 
1528 /*
1529  * Send a cap msg on the given inode.
1530  *
1531  * Caller should hold snap_rwsem (read), s_mutex.
1532  */
1533 static void __send_cap(struct cap_msg_args *arg, struct ceph_inode_info *ci)
1534 {
1535         struct ceph_msg *msg;
1536         struct inode *inode = &ci->netfs.inode;
1537         struct ceph_client *cl = ceph_inode_to_client(inode);
1538 
1539         msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, cap_msg_size(arg), GFP_NOFS,
1540                            false);
1541         if (!msg) {
1542                 pr_err_client(cl,
1543                               "error allocating cap msg: ino (%llx.%llx)"
1544                               " flushing %s tid %llu, requeuing cap.\n",
1545                               ceph_vinop(inode), ceph_cap_string(arg->dirty),
1546                               arg->flush_tid);
1547                 spin_lock(&ci->i_ceph_lock);
1548                 __cap_delay_requeue(arg->session->s_mdsc, ci);
1549                 spin_unlock(&ci->i_ceph_lock);
1550                 return;
1551         }
1552 
1553         encode_cap_msg(msg, arg);
1554         ceph_con_send(&arg->session->s_con, msg);
1555         ceph_buffer_put(arg->old_xattr_buf);
1556         ceph_buffer_put(arg->xattr_buf);
1557         if (arg->wake)
1558                 wake_up_all(&ci->i_cap_wq);
1559 }
1560 
1561 static inline int __send_flush_snap(struct inode *inode,
1562                                     struct ceph_mds_session *session,
1563                                     struct ceph_cap_snap *capsnap,
1564                                     u32 mseq, u64 oldest_flush_tid)
1565 {
1566         struct cap_msg_args     arg;
1567         struct ceph_msg         *msg;
1568 
1569         arg.session = session;
1570         arg.ino = ceph_vino(inode).ino;
1571         arg.cid = 0;
1572         arg.follows = capsnap->follows;
1573         arg.flush_tid = capsnap->cap_flush.tid;
1574         arg.oldest_flush_tid = oldest_flush_tid;
1575 
1576         arg.size = capsnap->size;
1577         arg.max_size = 0;
1578         arg.xattr_version = capsnap->xattr_version;
1579         arg.xattr_buf = capsnap->xattr_blob;
1580         arg.old_xattr_buf = NULL;
1581 
1582         arg.atime = capsnap->atime;
1583         arg.mtime = capsnap->mtime;
1584         arg.ctime = capsnap->ctime;
1585         arg.btime = capsnap->btime;
1586         arg.change_attr = capsnap->change_attr;
1587 
1588         arg.op = CEPH_CAP_OP_FLUSHSNAP;
1589         arg.caps = capsnap->issued;
1590         arg.wanted = 0;
1591         arg.dirty = capsnap->dirty;
1592 
1593         arg.seq = 0;
1594         arg.issue_seq = 0;
1595         arg.mseq = mseq;
1596         arg.time_warp_seq = capsnap->time_warp_seq;
1597 
1598         arg.uid = capsnap->uid;
1599         arg.gid = capsnap->gid;
1600         arg.mode = capsnap->mode;
1601 
1602         arg.inline_data = capsnap->inline_data;
1603         arg.flags = 0;
1604         arg.wake = false;
1605         arg.encrypted = IS_ENCRYPTED(inode);
1606 
1607         /* No fscrypt_auth changes from a capsnap.*/
1608         arg.fscrypt_auth_len = 0;
1609 
1610         msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, cap_msg_size(&arg),
1611                            GFP_NOFS, false);
1612         if (!msg)
1613                 return -ENOMEM;
1614 
1615         encode_cap_msg(msg, &arg);
1616         ceph_con_send(&arg.session->s_con, msg);
1617         return 0;
1618 }
1619 
1620 /*
1621  * When a snapshot is taken, clients accumulate dirty metadata on
1622  * inodes with capabilities in ceph_cap_snaps to describe the file
1623  * state at the time the snapshot was taken.  This must be flushed
1624  * asynchronously back to the MDS once sync writes complete and dirty
1625  * data is written out.
1626  *
1627  * Called under i_ceph_lock.
1628  */
1629 static void __ceph_flush_snaps(struct ceph_inode_info *ci,
1630                                struct ceph_mds_session *session)
1631                 __releases(ci->i_ceph_lock)
1632                 __acquires(ci->i_ceph_lock)
1633 {
1634         struct inode *inode = &ci->netfs.inode;
1635         struct ceph_mds_client *mdsc = session->s_mdsc;
1636         struct ceph_client *cl = mdsc->fsc->client;
1637         struct ceph_cap_snap *capsnap;
1638         u64 oldest_flush_tid = 0;
1639         u64 first_tid = 1, last_tid = 0;
1640 
1641         doutc(cl, "%p %llx.%llx session %p\n", inode, ceph_vinop(inode),
1642               session);
1643 
1644         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
1645                 /*
1646                  * we need to wait for sync writes to complete and for dirty
1647                  * pages to be written out.
1648                  */
1649                 if (capsnap->dirty_pages || capsnap->writing)
1650                         break;
1651 
1652                 /* should be removed by ceph_try_drop_cap_snap() */
1653                 BUG_ON(!capsnap->need_flush);
1654 
1655                 /* only flush each capsnap once */
1656                 if (capsnap->cap_flush.tid > 0) {
1657                         doutc(cl, "already flushed %p, skipping\n", capsnap);
1658                         continue;
1659                 }
1660 
1661                 spin_lock(&mdsc->cap_dirty_lock);
1662                 capsnap->cap_flush.tid = ++mdsc->last_cap_flush_tid;
1663                 list_add_tail(&capsnap->cap_flush.g_list,
1664                               &mdsc->cap_flush_list);
1665                 if (oldest_flush_tid == 0)
1666                         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
1667                 if (list_empty(&ci->i_flushing_item)) {
1668                         list_add_tail(&ci->i_flushing_item,
1669                                       &session->s_cap_flushing);
1670                 }
1671                 spin_unlock(&mdsc->cap_dirty_lock);
1672 
1673                 list_add_tail(&capsnap->cap_flush.i_list,
1674                               &ci->i_cap_flush_list);
1675 
1676                 if (first_tid == 1)
1677                         first_tid = capsnap->cap_flush.tid;
1678                 last_tid = capsnap->cap_flush.tid;
1679         }
1680 
1681         ci->i_ceph_flags &= ~CEPH_I_FLUSH_SNAPS;
1682 
1683         while (first_tid <= last_tid) {
1684                 struct ceph_cap *cap = ci->i_auth_cap;
1685                 struct ceph_cap_flush *cf = NULL, *iter;
1686                 int ret;
1687 
1688                 if (!(cap && cap->session == session)) {
1689                         doutc(cl, "%p %llx.%llx auth cap %p not mds%d, stop\n",
1690                               inode, ceph_vinop(inode), cap, session->s_mds);
1691                         break;
1692                 }
1693 
1694                 ret = -ENOENT;
1695                 list_for_each_entry(iter, &ci->i_cap_flush_list, i_list) {
1696                         if (iter->tid >= first_tid) {
1697                                 cf = iter;
1698                                 ret = 0;
1699                                 break;
1700                         }
1701                 }
1702                 if (ret < 0)
1703                         break;
1704 
1705                 first_tid = cf->tid + 1;
1706 
1707                 capsnap = container_of(cf, struct ceph_cap_snap, cap_flush);
1708                 refcount_inc(&capsnap->nref);
1709                 spin_unlock(&ci->i_ceph_lock);
1710 
1711                 doutc(cl, "%p %llx.%llx capsnap %p tid %llu %s\n", inode,
1712                       ceph_vinop(inode), capsnap, cf->tid,
1713                       ceph_cap_string(capsnap->dirty));
1714 
1715                 ret = __send_flush_snap(inode, session, capsnap, cap->mseq,
1716                                         oldest_flush_tid);
1717                 if (ret < 0) {
1718                         pr_err_client(cl, "error sending cap flushsnap, "
1719                                       "ino (%llx.%llx) tid %llu follows %llu\n",
1720                                       ceph_vinop(inode), cf->tid,
1721                                       capsnap->follows);
1722                 }
1723 
1724                 ceph_put_cap_snap(capsnap);
1725                 spin_lock(&ci->i_ceph_lock);
1726         }
1727 }
1728 
1729 void ceph_flush_snaps(struct ceph_inode_info *ci,
1730                       struct ceph_mds_session **psession)
1731 {
1732         struct inode *inode = &ci->netfs.inode;
1733         struct ceph_mds_client *mdsc = ceph_inode_to_fs_client(inode)->mdsc;
1734         struct ceph_client *cl = ceph_inode_to_client(inode);
1735         struct ceph_mds_session *session = NULL;
1736         bool need_put = false;
1737         int mds;
1738 
1739         doutc(cl, "%p %llx.%llx\n", inode, ceph_vinop(inode));
1740         if (psession)
1741                 session = *psession;
1742 retry:
1743         spin_lock(&ci->i_ceph_lock);
1744         if (!(ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS)) {
1745                 doutc(cl, " no capsnap needs flush, doing nothing\n");
1746                 goto out;
1747         }
1748         if (!ci->i_auth_cap) {
1749                 doutc(cl, " no auth cap (migrating?), doing nothing\n");
1750                 goto out;
1751         }
1752 
1753         mds = ci->i_auth_cap->session->s_mds;
1754         if (session && session->s_mds != mds) {
1755                 doutc(cl, " oops, wrong session %p mutex\n", session);
1756                 ceph_put_mds_session(session);
1757                 session = NULL;
1758         }
1759         if (!session) {
1760                 spin_unlock(&ci->i_ceph_lock);
1761                 mutex_lock(&mdsc->mutex);
1762                 session = __ceph_lookup_mds_session(mdsc, mds);
1763                 mutex_unlock(&mdsc->mutex);
1764                 goto retry;
1765         }
1766 
1767         // make sure flushsnap messages are sent in proper order.
1768         if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH)
1769                 __kick_flushing_caps(mdsc, session, ci, 0);
1770 
1771         __ceph_flush_snaps(ci, session);
1772 out:
1773         spin_unlock(&ci->i_ceph_lock);
1774 
1775         if (psession)
1776                 *psession = session;
1777         else
1778                 ceph_put_mds_session(session);
1779         /* we flushed them all; remove this inode from the queue */
1780         spin_lock(&mdsc->snap_flush_lock);
1781         if (!list_empty(&ci->i_snap_flush_item))
1782                 need_put = true;
1783         list_del_init(&ci->i_snap_flush_item);
1784         spin_unlock(&mdsc->snap_flush_lock);
1785 
1786         if (need_put)
1787                 iput(inode);
1788 }
1789 
1790 /*
1791  * Mark caps dirty.  If inode is newly dirty, return the dirty flags.
1792  * Caller is then responsible for calling __mark_inode_dirty with the
1793  * returned flags value.
1794  */
1795 int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask,
1796                            struct ceph_cap_flush **pcf)
1797 {
1798         struct ceph_mds_client *mdsc =
1799                 ceph_sb_to_fs_client(ci->netfs.inode.i_sb)->mdsc;
1800         struct inode *inode = &ci->netfs.inode;
1801         struct ceph_client *cl = ceph_inode_to_client(inode);
1802         int was = ci->i_dirty_caps;
1803         int dirty = 0;
1804 
1805         lockdep_assert_held(&ci->i_ceph_lock);
1806 
1807         if (!ci->i_auth_cap) {
1808                 pr_warn_client(cl, "%p %llx.%llx mask %s, "
1809                                "but no auth cap (session was closed?)\n",
1810                                 inode, ceph_vinop(inode),
1811                                 ceph_cap_string(mask));
1812                 return 0;
1813         }
1814 
1815         doutc(cl, "%p %llx.%llx %s dirty %s -> %s\n", inode,
1816               ceph_vinop(inode), ceph_cap_string(mask),
1817               ceph_cap_string(was), ceph_cap_string(was | mask));
1818         ci->i_dirty_caps |= mask;
1819         if (was == 0) {
1820                 struct ceph_mds_session *session = ci->i_auth_cap->session;
1821 
1822                 WARN_ON_ONCE(ci->i_prealloc_cap_flush);
1823                 swap(ci->i_prealloc_cap_flush, *pcf);
1824 
1825                 if (!ci->i_head_snapc) {
1826                         WARN_ON_ONCE(!rwsem_is_locked(&mdsc->snap_rwsem));
1827                         ci->i_head_snapc = ceph_get_snap_context(
1828                                 ci->i_snap_realm->cached_context);
1829                 }
1830                 doutc(cl, "%p %llx.%llx now dirty snapc %p auth cap %p\n",
1831                       inode, ceph_vinop(inode), ci->i_head_snapc,
1832                       ci->i_auth_cap);
1833                 BUG_ON(!list_empty(&ci->i_dirty_item));
1834                 spin_lock(&mdsc->cap_dirty_lock);
1835                 list_add(&ci->i_dirty_item, &session->s_cap_dirty);
1836                 spin_unlock(&mdsc->cap_dirty_lock);
1837                 if (ci->i_flushing_caps == 0) {
1838                         ihold(inode);
1839                         dirty |= I_DIRTY_SYNC;
1840                 }
1841         } else {
1842                 WARN_ON_ONCE(!ci->i_prealloc_cap_flush);
1843         }
1844         BUG_ON(list_empty(&ci->i_dirty_item));
1845         if (((was | ci->i_flushing_caps) & CEPH_CAP_FILE_BUFFER) &&
1846             (mask & CEPH_CAP_FILE_BUFFER))
1847                 dirty |= I_DIRTY_DATASYNC;
1848         __cap_delay_requeue(mdsc, ci);
1849         return dirty;
1850 }
1851 
1852 struct ceph_cap_flush *ceph_alloc_cap_flush(void)
1853 {
1854         struct ceph_cap_flush *cf;
1855 
1856         cf = kmem_cache_alloc(ceph_cap_flush_cachep, GFP_KERNEL);
1857         if (!cf)
1858                 return NULL;
1859 
1860         cf->is_capsnap = false;
1861         return cf;
1862 }
1863 
1864 void ceph_free_cap_flush(struct ceph_cap_flush *cf)
1865 {
1866         if (cf)
1867                 kmem_cache_free(ceph_cap_flush_cachep, cf);
1868 }
1869 
1870 static u64 __get_oldest_flush_tid(struct ceph_mds_client *mdsc)
1871 {
1872         if (!list_empty(&mdsc->cap_flush_list)) {
1873                 struct ceph_cap_flush *cf =
1874                         list_first_entry(&mdsc->cap_flush_list,
1875                                          struct ceph_cap_flush, g_list);
1876                 return cf->tid;
1877         }
1878         return 0;
1879 }
1880 
1881 /*
1882  * Remove cap_flush from the mdsc's or inode's flushing cap list.
1883  * Return true if caller needs to wake up flush waiters.
1884  */
1885 static bool __detach_cap_flush_from_mdsc(struct ceph_mds_client *mdsc,
1886                                          struct ceph_cap_flush *cf)
1887 {
1888         struct ceph_cap_flush *prev;
1889         bool wake = cf->wake;
1890 
1891         if (wake && cf->g_list.prev != &mdsc->cap_flush_list) {
1892                 prev = list_prev_entry(cf, g_list);
1893                 prev->wake = true;
1894                 wake = false;
1895         }
1896         list_del_init(&cf->g_list);
1897         return wake;
1898 }
1899 
1900 static bool __detach_cap_flush_from_ci(struct ceph_inode_info *ci,
1901                                        struct ceph_cap_flush *cf)
1902 {
1903         struct ceph_cap_flush *prev;
1904         bool wake = cf->wake;
1905 
1906         if (wake && cf->i_list.prev != &ci->i_cap_flush_list) {
1907                 prev = list_prev_entry(cf, i_list);
1908                 prev->wake = true;
1909                 wake = false;
1910         }
1911         list_del_init(&cf->i_list);
1912         return wake;
1913 }
1914 
1915 /*
1916  * Add dirty inode to the flushing list.  Assigned a seq number so we
1917  * can wait for caps to flush without starving.
1918  *
1919  * Called under i_ceph_lock. Returns the flush tid.
1920  */
1921 static u64 __mark_caps_flushing(struct inode *inode,
1922                                 struct ceph_mds_session *session, bool wake,
1923                                 u64 *oldest_flush_tid)
1924 {
1925         struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(inode->i_sb)->mdsc;
1926         struct ceph_client *cl = ceph_inode_to_client(inode);
1927         struct ceph_inode_info *ci = ceph_inode(inode);
1928         struct ceph_cap_flush *cf = NULL;
1929         int flushing;
1930 
1931         lockdep_assert_held(&ci->i_ceph_lock);
1932         BUG_ON(ci->i_dirty_caps == 0);
1933         BUG_ON(list_empty(&ci->i_dirty_item));
1934         BUG_ON(!ci->i_prealloc_cap_flush);
1935 
1936         flushing = ci->i_dirty_caps;
1937         doutc(cl, "flushing %s, flushing_caps %s -> %s\n",
1938               ceph_cap_string(flushing),
1939               ceph_cap_string(ci->i_flushing_caps),
1940               ceph_cap_string(ci->i_flushing_caps | flushing));
1941         ci->i_flushing_caps |= flushing;
1942         ci->i_dirty_caps = 0;
1943         doutc(cl, "%p %llx.%llx now !dirty\n", inode, ceph_vinop(inode));
1944 
1945         swap(cf, ci->i_prealloc_cap_flush);
1946         cf->caps = flushing;
1947         cf->wake = wake;
1948 
1949         spin_lock(&mdsc->cap_dirty_lock);
1950         list_del_init(&ci->i_dirty_item);
1951 
1952         cf->tid = ++mdsc->last_cap_flush_tid;
1953         list_add_tail(&cf->g_list, &mdsc->cap_flush_list);
1954         *oldest_flush_tid = __get_oldest_flush_tid(mdsc);
1955 
1956         if (list_empty(&ci->i_flushing_item)) {
1957                 list_add_tail(&ci->i_flushing_item, &session->s_cap_flushing);
1958                 mdsc->num_cap_flushing++;
1959         }
1960         spin_unlock(&mdsc->cap_dirty_lock);
1961 
1962         list_add_tail(&cf->i_list, &ci->i_cap_flush_list);
1963 
1964         return cf->tid;
1965 }
1966 
1967 /*
1968  * try to invalidate mapping pages without blocking.
1969  */
1970 static int try_nonblocking_invalidate(struct inode *inode)
1971         __releases(ci->i_ceph_lock)
1972         __acquires(ci->i_ceph_lock)
1973 {
1974         struct ceph_client *cl = ceph_inode_to_client(inode);
1975         struct ceph_inode_info *ci = ceph_inode(inode);
1976         u32 invalidating_gen = ci->i_rdcache_gen;
1977 
1978         spin_unlock(&ci->i_ceph_lock);
1979         ceph_fscache_invalidate(inode, false);
1980         invalidate_mapping_pages(&inode->i_data, 0, -1);
1981         spin_lock(&ci->i_ceph_lock);
1982 
1983         if (inode->i_data.nrpages == 0 &&
1984             invalidating_gen == ci->i_rdcache_gen) {
1985                 /* success. */
1986                 doutc(cl, "%p %llx.%llx success\n", inode,
1987                       ceph_vinop(inode));
1988                 /* save any racing async invalidate some trouble */
1989                 ci->i_rdcache_revoking = ci->i_rdcache_gen - 1;
1990                 return 0;
1991         }
1992         doutc(cl, "%p %llx.%llx failed\n", inode, ceph_vinop(inode));
1993         return -1;
1994 }
1995 
1996 bool __ceph_should_report_size(struct ceph_inode_info *ci)
1997 {
1998         loff_t size = i_size_read(&ci->netfs.inode);
1999         /* mds will adjust max size according to the reported size */
2000         if (ci->i_flushing_caps & CEPH_CAP_FILE_WR)
2001                 return false;
2002         if (size >= ci->i_max_size)
2003                 return true;
2004         /* half of previous max_size increment has been used */
2005         if (ci->i_max_size > ci->i_reported_size &&
2006             (size << 1) >= ci->i_max_size + ci->i_reported_size)
2007                 return true;
2008         return false;
2009 }
2010 
2011 /*
2012  * Swiss army knife function to examine currently used and wanted
2013  * versus held caps.  Release, flush, ack revoked caps to mds as
2014  * appropriate.
2015  *
2016  *  CHECK_CAPS_AUTHONLY - we should only check the auth cap
2017  *  CHECK_CAPS_FLUSH - we should flush any dirty caps immediately, without
2018  *    further delay.
2019  *  CHECK_CAPS_FLUSH_FORCE - we should flush any caps immediately, without
2020  *    further delay.
2021  */
2022 void ceph_check_caps(struct ceph_inode_info *ci, int flags)
2023 {
2024         struct inode *inode = &ci->netfs.inode;
2025         struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
2026         struct ceph_client *cl = ceph_inode_to_client(inode);
2027         struct ceph_cap *cap;
2028         u64 flush_tid, oldest_flush_tid;
2029         int file_wanted, used, cap_used;
2030         int issued, implemented, want, retain, revoking, flushing = 0;
2031         int mds = -1;   /* keep track of how far we've gone through i_caps list
2032                            to avoid an infinite loop on retry */
2033         struct rb_node *p;
2034         bool queue_invalidate = false;
2035         bool tried_invalidate = false;
2036         bool queue_writeback = false;
2037         struct ceph_mds_session *session = NULL;
2038 
2039         spin_lock(&ci->i_ceph_lock);
2040         if (ci->i_ceph_flags & CEPH_I_ASYNC_CREATE) {
2041                 ci->i_ceph_flags |= CEPH_I_ASYNC_CHECK_CAPS;
2042 
2043                 /* Don't send messages until we get async create reply */
2044                 spin_unlock(&ci->i_ceph_lock);
2045                 return;
2046         }
2047 
2048         if (ci->i_ceph_flags & CEPH_I_FLUSH)
2049                 flags |= CHECK_CAPS_FLUSH;
2050 retry:
2051         /* Caps wanted by virtue of active open files. */
2052         file_wanted = __ceph_caps_file_wanted(ci);
2053 
2054         /* Caps which have active references against them */
2055         used = __ceph_caps_used(ci);
2056 
2057         /*
2058          * "issued" represents the current caps that the MDS wants us to have.
2059          * "implemented" is the set that we have been granted, and includes the
2060          * ones that have not yet been returned to the MDS (the "revoking" set,
2061          * usually because they have outstanding references).
2062          */
2063         issued = __ceph_caps_issued(ci, &implemented);
2064         revoking = implemented & ~issued;
2065 
2066         want = file_wanted;
2067 
2068         /* The ones we currently want to retain (may be adjusted below) */
2069         retain = file_wanted | used | CEPH_CAP_PIN;
2070         if (!mdsc->stopping && inode->i_nlink > 0) {
2071                 if (file_wanted) {
2072                         retain |= CEPH_CAP_ANY;       /* be greedy */
2073                 } else if (S_ISDIR(inode->i_mode) &&
2074                            (issued & CEPH_CAP_FILE_SHARED) &&
2075                            __ceph_dir_is_complete(ci)) {
2076                         /*
2077                          * If a directory is complete, we want to keep
2078                          * the exclusive cap. So that MDS does not end up
2079                          * revoking the shared cap on every create/unlink
2080                          * operation.
2081                          */
2082                         if (IS_RDONLY(inode)) {
2083                                 want = CEPH_CAP_ANY_SHARED;
2084                         } else {
2085                                 want |= CEPH_CAP_ANY_SHARED | CEPH_CAP_FILE_EXCL;
2086                         }
2087                         retain |= want;
2088                 } else {
2089 
2090                         retain |= CEPH_CAP_ANY_SHARED;
2091                         /*
2092                          * keep RD only if we didn't have the file open RW,
2093                          * because then the mds would revoke it anyway to
2094                          * journal max_size=0.
2095                          */
2096                         if (ci->i_max_size == 0)
2097                                 retain |= CEPH_CAP_ANY_RD;
2098                 }
2099         }
2100 
2101         doutc(cl, "%p %llx.%llx file_want %s used %s dirty %s "
2102               "flushing %s issued %s revoking %s retain %s %s%s%s%s\n",
2103              inode, ceph_vinop(inode), ceph_cap_string(file_wanted),
2104              ceph_cap_string(used), ceph_cap_string(ci->i_dirty_caps),
2105              ceph_cap_string(ci->i_flushing_caps),
2106              ceph_cap_string(issued), ceph_cap_string(revoking),
2107              ceph_cap_string(retain),
2108              (flags & CHECK_CAPS_AUTHONLY) ? " AUTHONLY" : "",
2109              (flags & CHECK_CAPS_FLUSH) ? " FLUSH" : "",
2110              (flags & CHECK_CAPS_NOINVAL) ? " NOINVAL" : "",
2111              (flags & CHECK_CAPS_FLUSH_FORCE) ? " FLUSH_FORCE" : "");
2112 
2113         /*
2114          * If we no longer need to hold onto old our caps, and we may
2115          * have cached pages, but don't want them, then try to invalidate.
2116          * If we fail, it's because pages are locked.... try again later.
2117          */
2118         if ((!(flags & CHECK_CAPS_NOINVAL) || mdsc->stopping) &&
2119             S_ISREG(inode->i_mode) &&
2120             !(ci->i_wb_ref || ci->i_wrbuffer_ref) &&   /* no dirty pages... */
2121             inode->i_data.nrpages &&            /* have cached pages */
2122             (revoking & (CEPH_CAP_FILE_CACHE|
2123                          CEPH_CAP_FILE_LAZYIO)) && /*  or revoking cache */
2124             !tried_invalidate) {
2125                 doutc(cl, "trying to invalidate on %p %llx.%llx\n",
2126                       inode, ceph_vinop(inode));
2127                 if (try_nonblocking_invalidate(inode) < 0) {
2128                         doutc(cl, "queuing invalidate\n");
2129                         queue_invalidate = true;
2130                         ci->i_rdcache_revoking = ci->i_rdcache_gen;
2131                 }
2132                 tried_invalidate = true;
2133                 goto retry;
2134         }
2135 
2136         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
2137                 int mflags = 0;
2138                 struct cap_msg_args arg;
2139 
2140                 cap = rb_entry(p, struct ceph_cap, ci_node);
2141 
2142                 /* avoid looping forever */
2143                 if (mds >= cap->mds ||
2144                     ((flags & CHECK_CAPS_AUTHONLY) && cap != ci->i_auth_cap))
2145                         continue;
2146 
2147                 /*
2148                  * If we have an auth cap, we don't need to consider any
2149                  * overlapping caps as used.
2150                  */
2151                 cap_used = used;
2152                 if (ci->i_auth_cap && cap != ci->i_auth_cap)
2153                         cap_used &= ~ci->i_auth_cap->issued;
2154 
2155                 revoking = cap->implemented & ~cap->issued;
2156                 doutc(cl, " mds%d cap %p used %s issued %s implemented %s revoking %s\n",
2157                       cap->mds, cap, ceph_cap_string(cap_used),
2158                       ceph_cap_string(cap->issued),
2159                       ceph_cap_string(cap->implemented),
2160                       ceph_cap_string(revoking));
2161 
2162                 /* completed revocation? going down and there are no caps? */
2163                 if (revoking) {
2164                         if ((revoking & cap_used) == 0) {
2165                                 doutc(cl, "completed revocation of %s\n",
2166                                       ceph_cap_string(cap->implemented & ~cap->issued));
2167                                 goto ack;
2168                         }
2169 
2170                         /*
2171                          * If the "i_wrbuffer_ref" was increased by mmap or generic
2172                          * cache write just before the ceph_check_caps() is called,
2173                          * the Fb capability revoking will fail this time. Then we
2174                          * must wait for the BDI's delayed work to flush the dirty
2175                          * pages and to release the "i_wrbuffer_ref", which will cost
2176                          * at most 5 seconds. That means the MDS needs to wait at
2177                          * most 5 seconds to finished the Fb capability's revocation.
2178                          *
2179                          * Let's queue a writeback for it.
2180                          */
2181                         if (S_ISREG(inode->i_mode) && ci->i_wrbuffer_ref &&
2182                             (revoking & CEPH_CAP_FILE_BUFFER))
2183                                 queue_writeback = true;
2184                 }
2185 
2186                 if (flags & CHECK_CAPS_FLUSH_FORCE) {
2187                         doutc(cl, "force to flush caps\n");
2188                         goto ack;
2189                 }
2190 
2191                 if (cap == ci->i_auth_cap &&
2192                     (cap->issued & CEPH_CAP_FILE_WR)) {
2193                         /* request larger max_size from MDS? */
2194                         if (ci->i_wanted_max_size > ci->i_max_size &&
2195                             ci->i_wanted_max_size > ci->i_requested_max_size) {
2196                                 doutc(cl, "requesting new max_size\n");
2197                                 goto ack;
2198                         }
2199 
2200                         /* approaching file_max? */
2201                         if (__ceph_should_report_size(ci)) {
2202                                 doutc(cl, "i_size approaching max_size\n");
2203                                 goto ack;
2204                         }
2205                 }
2206                 /* flush anything dirty? */
2207                 if (cap == ci->i_auth_cap) {
2208                         if ((flags & CHECK_CAPS_FLUSH) && ci->i_dirty_caps) {
2209                                 doutc(cl, "flushing dirty caps\n");
2210                                 goto ack;
2211                         }
2212                         if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS) {
2213                                 doutc(cl, "flushing snap caps\n");
2214                                 goto ack;
2215                         }
2216                 }
2217 
2218                 /* want more caps from mds? */
2219                 if (want & ~cap->mds_wanted) {
2220                         if (want & ~(cap->mds_wanted | cap->issued))
2221                                 goto ack;
2222                         if (!__cap_is_valid(cap))
2223                                 goto ack;
2224                 }
2225 
2226                 /* things we might delay */
2227                 if ((cap->issued & ~retain) == 0)
2228                         continue;     /* nope, all good */
2229 
2230 ack:
2231                 ceph_put_mds_session(session);
2232                 session = ceph_get_mds_session(cap->session);
2233 
2234                 /* kick flushing and flush snaps before sending normal
2235                  * cap message */
2236                 if (cap == ci->i_auth_cap &&
2237                     (ci->i_ceph_flags &
2238                      (CEPH_I_KICK_FLUSH | CEPH_I_FLUSH_SNAPS))) {
2239                         if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH)
2240                                 __kick_flushing_caps(mdsc, session, ci, 0);
2241                         if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS)
2242                                 __ceph_flush_snaps(ci, session);
2243 
2244                         goto retry;
2245                 }
2246 
2247                 if (cap == ci->i_auth_cap && ci->i_dirty_caps) {
2248                         flushing = ci->i_dirty_caps;
2249                         flush_tid = __mark_caps_flushing(inode, session, false,
2250                                                          &oldest_flush_tid);
2251                         if (flags & CHECK_CAPS_FLUSH &&
2252                             list_empty(&session->s_cap_dirty))
2253                                 mflags |= CEPH_CLIENT_CAPS_SYNC;
2254                 } else {
2255                         flushing = 0;
2256                         flush_tid = 0;
2257                         spin_lock(&mdsc->cap_dirty_lock);
2258                         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2259                         spin_unlock(&mdsc->cap_dirty_lock);
2260                 }
2261 
2262                 mds = cap->mds;  /* remember mds, so we don't repeat */
2263 
2264                 __prep_cap(&arg, cap, CEPH_CAP_OP_UPDATE, mflags, cap_used,
2265                            want, retain, flushing, flush_tid, oldest_flush_tid);
2266 
2267                 spin_unlock(&ci->i_ceph_lock);
2268                 __send_cap(&arg, ci);
2269                 spin_lock(&ci->i_ceph_lock);
2270 
2271                 goto retry; /* retake i_ceph_lock and restart our cap scan. */
2272         }
2273 
2274         /* periodically re-calculate caps wanted by open files */
2275         if (__ceph_is_any_real_caps(ci) &&
2276             list_empty(&ci->i_cap_delay_list) &&
2277             (file_wanted & ~CEPH_CAP_PIN) &&
2278             !(used & (CEPH_CAP_FILE_RD | CEPH_CAP_ANY_FILE_WR))) {
2279                 __cap_delay_requeue(mdsc, ci);
2280         }
2281 
2282         spin_unlock(&ci->i_ceph_lock);
2283 
2284         ceph_put_mds_session(session);
2285         if (queue_writeback)
2286                 ceph_queue_writeback(inode);
2287         if (queue_invalidate)
2288                 ceph_queue_invalidate(inode);
2289 }
2290 
2291 /*
2292  * Try to flush dirty caps back to the auth mds.
2293  */
2294 static int try_flush_caps(struct inode *inode, u64 *ptid)
2295 {
2296         struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(inode->i_sb)->mdsc;
2297         struct ceph_inode_info *ci = ceph_inode(inode);
2298         int flushing = 0;
2299         u64 flush_tid = 0, oldest_flush_tid = 0;
2300 
2301         spin_lock(&ci->i_ceph_lock);
2302 retry_locked:
2303         if (ci->i_dirty_caps && ci->i_auth_cap) {
2304                 struct ceph_cap *cap = ci->i_auth_cap;
2305                 struct cap_msg_args arg;
2306                 struct ceph_mds_session *session = cap->session;
2307 
2308                 if (session->s_state < CEPH_MDS_SESSION_OPEN) {
2309                         spin_unlock(&ci->i_ceph_lock);
2310                         goto out;
2311                 }
2312 
2313                 if (ci->i_ceph_flags &
2314                     (CEPH_I_KICK_FLUSH | CEPH_I_FLUSH_SNAPS)) {
2315                         if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH)
2316                                 __kick_flushing_caps(mdsc, session, ci, 0);
2317                         if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS)
2318                                 __ceph_flush_snaps(ci, session);
2319                         goto retry_locked;
2320                 }
2321 
2322                 flushing = ci->i_dirty_caps;
2323                 flush_tid = __mark_caps_flushing(inode, session, true,
2324                                                  &oldest_flush_tid);
2325 
2326                 __prep_cap(&arg, cap, CEPH_CAP_OP_FLUSH, CEPH_CLIENT_CAPS_SYNC,
2327                            __ceph_caps_used(ci), __ceph_caps_wanted(ci),
2328                            (cap->issued | cap->implemented),
2329                            flushing, flush_tid, oldest_flush_tid);
2330                 spin_unlock(&ci->i_ceph_lock);
2331 
2332                 __send_cap(&arg, ci);
2333         } else {
2334                 if (!list_empty(&ci->i_cap_flush_list)) {
2335                         struct ceph_cap_flush *cf =
2336                                 list_last_entry(&ci->i_cap_flush_list,
2337                                                 struct ceph_cap_flush, i_list);
2338                         cf->wake = true;
2339                         flush_tid = cf->tid;
2340                 }
2341                 flushing = ci->i_flushing_caps;
2342                 spin_unlock(&ci->i_ceph_lock);
2343         }
2344 out:
2345         *ptid = flush_tid;
2346         return flushing;
2347 }
2348 
2349 /*
2350  * Return true if we've flushed caps through the given flush_tid.
2351  */
2352 static int caps_are_flushed(struct inode *inode, u64 flush_tid)
2353 {
2354         struct ceph_inode_info *ci = ceph_inode(inode);
2355         int ret = 1;
2356 
2357         spin_lock(&ci->i_ceph_lock);
2358         if (!list_empty(&ci->i_cap_flush_list)) {
2359                 struct ceph_cap_flush * cf =
2360                         list_first_entry(&ci->i_cap_flush_list,
2361                                          struct ceph_cap_flush, i_list);
2362                 if (cf->tid <= flush_tid)
2363                         ret = 0;
2364         }
2365         spin_unlock(&ci->i_ceph_lock);
2366         return ret;
2367 }
2368 
2369 /*
2370  * flush the mdlog and wait for any unsafe requests to complete.
2371  */
2372 static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode)
2373 {
2374         struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(inode->i_sb)->mdsc;
2375         struct ceph_client *cl = ceph_inode_to_client(inode);
2376         struct ceph_inode_info *ci = ceph_inode(inode);
2377         struct ceph_mds_request *req1 = NULL, *req2 = NULL;
2378         int ret, err = 0;
2379 
2380         spin_lock(&ci->i_unsafe_lock);
2381         if (S_ISDIR(inode->i_mode) && !list_empty(&ci->i_unsafe_dirops)) {
2382                 req1 = list_last_entry(&ci->i_unsafe_dirops,
2383                                         struct ceph_mds_request,
2384                                         r_unsafe_dir_item);
2385                 ceph_mdsc_get_request(req1);
2386         }
2387         if (!list_empty(&ci->i_unsafe_iops)) {
2388                 req2 = list_last_entry(&ci->i_unsafe_iops,
2389                                         struct ceph_mds_request,
2390                                         r_unsafe_target_item);
2391                 ceph_mdsc_get_request(req2);
2392         }
2393         spin_unlock(&ci->i_unsafe_lock);
2394 
2395         /*
2396          * Trigger to flush the journal logs in all the relevant MDSes
2397          * manually, or in the worst case we must wait at most 5 seconds
2398          * to wait the journal logs to be flushed by the MDSes periodically.
2399          */
2400         if (req1 || req2) {
2401                 struct ceph_mds_request *req;
2402                 struct ceph_mds_session **sessions;
2403                 struct ceph_mds_session *s;
2404                 unsigned int max_sessions;
2405                 int i;
2406 
2407                 mutex_lock(&mdsc->mutex);
2408                 max_sessions = mdsc->max_sessions;
2409 
2410                 sessions = kcalloc(max_sessions, sizeof(s), GFP_KERNEL);
2411                 if (!sessions) {
2412                         mutex_unlock(&mdsc->mutex);
2413                         err = -ENOMEM;
2414                         goto out;
2415                 }
2416 
2417                 spin_lock(&ci->i_unsafe_lock);
2418                 if (req1) {
2419                         list_for_each_entry(req, &ci->i_unsafe_dirops,
2420                                             r_unsafe_dir_item) {
2421                                 s = req->r_session;
2422                                 if (!s)
2423                                         continue;
2424                                 if (!sessions[s->s_mds]) {
2425                                         s = ceph_get_mds_session(s);
2426                                         sessions[s->s_mds] = s;
2427                                 }
2428                         }
2429                 }
2430                 if (req2) {
2431                         list_for_each_entry(req, &ci->i_unsafe_iops,
2432                                             r_unsafe_target_item) {
2433                                 s = req->r_session;
2434                                 if (!s)
2435                                         continue;
2436                                 if (!sessions[s->s_mds]) {
2437                                         s = ceph_get_mds_session(s);
2438                                         sessions[s->s_mds] = s;
2439                                 }
2440                         }
2441                 }
2442                 spin_unlock(&ci->i_unsafe_lock);
2443 
2444                 /* the auth MDS */
2445                 spin_lock(&ci->i_ceph_lock);
2446                 if (ci->i_auth_cap) {
2447                         s = ci->i_auth_cap->session;
2448                         if (!sessions[s->s_mds])
2449                                 sessions[s->s_mds] = ceph_get_mds_session(s);
2450                 }
2451                 spin_unlock(&ci->i_ceph_lock);
2452                 mutex_unlock(&mdsc->mutex);
2453 
2454                 /* send flush mdlog request to MDSes */
2455                 for (i = 0; i < max_sessions; i++) {
2456                         s = sessions[i];
2457                         if (s) {
2458                                 send_flush_mdlog(s);
2459                                 ceph_put_mds_session(s);
2460                         }
2461                 }
2462                 kfree(sessions);
2463         }
2464 
2465         doutc(cl, "%p %llx.%llx wait on tid %llu %llu\n", inode,
2466               ceph_vinop(inode), req1 ? req1->r_tid : 0ULL,
2467               req2 ? req2->r_tid : 0ULL);
2468         if (req1) {
2469                 ret = !wait_for_completion_timeout(&req1->r_safe_completion,
2470                                         ceph_timeout_jiffies(req1->r_timeout));
2471                 if (ret)
2472                         err = -EIO;
2473         }
2474         if (req2) {
2475                 ret = !wait_for_completion_timeout(&req2->r_safe_completion,
2476                                         ceph_timeout_jiffies(req2->r_timeout));
2477                 if (ret)
2478                         err = -EIO;
2479         }
2480 
2481 out:
2482         if (req1)
2483                 ceph_mdsc_put_request(req1);
2484         if (req2)
2485                 ceph_mdsc_put_request(req2);
2486         return err;
2487 }
2488 
2489 int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync)
2490 {
2491         struct inode *inode = file->f_mapping->host;
2492         struct ceph_inode_info *ci = ceph_inode(inode);
2493         struct ceph_client *cl = ceph_inode_to_client(inode);
2494         u64 flush_tid;
2495         int ret, err;
2496         int dirty;
2497 
2498         doutc(cl, "%p %llx.%llx%s\n", inode, ceph_vinop(inode),
2499               datasync ? " datasync" : "");
2500 
2501         ret = file_write_and_wait_range(file, start, end);
2502         if (datasync)
2503                 goto out;
2504 
2505         ret = ceph_wait_on_async_create(inode);
2506         if (ret)
2507                 goto out;
2508 
2509         dirty = try_flush_caps(inode, &flush_tid);
2510         doutc(cl, "dirty caps are %s\n", ceph_cap_string(dirty));
2511 
2512         err = flush_mdlog_and_wait_inode_unsafe_requests(inode);
2513 
2514         /*
2515          * only wait on non-file metadata writeback (the mds
2516          * can recover size and mtime, so we don't need to
2517          * wait for that)
2518          */
2519         if (!err && (dirty & ~CEPH_CAP_ANY_FILE_WR)) {
2520                 err = wait_event_interruptible(ci->i_cap_wq,
2521                                         caps_are_flushed(inode, flush_tid));
2522         }
2523 
2524         if (err < 0)
2525                 ret = err;
2526 
2527         err = file_check_and_advance_wb_err(file);
2528         if (err < 0)
2529                 ret = err;
2530 out:
2531         doutc(cl, "%p %llx.%llx%s result=%d\n", inode, ceph_vinop(inode),
2532               datasync ? " datasync" : "", ret);
2533         return ret;
2534 }
2535 
2536 /*
2537  * Flush any dirty caps back to the mds.  If we aren't asked to wait,
2538  * queue inode for flush but don't do so immediately, because we can
2539  * get by with fewer MDS messages if we wait for data writeback to
2540  * complete first.
2541  */
2542 int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)
2543 {
2544         struct ceph_inode_info *ci = ceph_inode(inode);
2545         struct ceph_client *cl = ceph_inode_to_client(inode);
2546         u64 flush_tid;
2547         int err = 0;
2548         int dirty;
2549         int wait = (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync);
2550 
2551         doutc(cl, "%p %llx.%llx wait=%d\n", inode, ceph_vinop(inode), wait);
2552         ceph_fscache_unpin_writeback(inode, wbc);
2553         if (wait) {
2554                 err = ceph_wait_on_async_create(inode);
2555                 if (err)
2556                         return err;
2557                 dirty = try_flush_caps(inode, &flush_tid);
2558                 if (dirty)
2559                         err = wait_event_interruptible(ci->i_cap_wq,
2560                                        caps_are_flushed(inode, flush_tid));
2561         } else {
2562                 struct ceph_mds_client *mdsc =
2563                         ceph_sb_to_fs_client(inode->i_sb)->mdsc;
2564 
2565                 spin_lock(&ci->i_ceph_lock);
2566                 if (__ceph_caps_dirty(ci))
2567                         __cap_delay_requeue_front(mdsc, ci);
2568                 spin_unlock(&ci->i_ceph_lock);
2569         }
2570         return err;
2571 }
2572 
2573 static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
2574                                  struct ceph_mds_session *session,
2575                                  struct ceph_inode_info *ci,
2576                                  u64 oldest_flush_tid)
2577         __releases(ci->i_ceph_lock)
2578         __acquires(ci->i_ceph_lock)
2579 {
2580         struct inode *inode = &ci->netfs.inode;
2581         struct ceph_client *cl = mdsc->fsc->client;
2582         struct ceph_cap *cap;
2583         struct ceph_cap_flush *cf;
2584         int ret;
2585         u64 first_tid = 0;
2586         u64 last_snap_flush = 0;
2587 
2588         /* Don't do anything until create reply comes in */
2589         if (ci->i_ceph_flags & CEPH_I_ASYNC_CREATE)
2590                 return;
2591 
2592         ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
2593 
2594         list_for_each_entry_reverse(cf, &ci->i_cap_flush_list, i_list) {
2595                 if (cf->is_capsnap) {
2596                         last_snap_flush = cf->tid;
2597                         break;
2598                 }
2599         }
2600 
2601         list_for_each_entry(cf, &ci->i_cap_flush_list, i_list) {
2602                 if (cf->tid < first_tid)
2603                         continue;
2604 
2605                 cap = ci->i_auth_cap;
2606                 if (!(cap && cap->session == session)) {
2607                         pr_err_client(cl, "%p auth cap %p not mds%d ???\n",
2608                                       inode, cap, session->s_mds);
2609                         break;
2610                 }
2611 
2612                 first_tid = cf->tid + 1;
2613 
2614                 if (!cf->is_capsnap) {
2615                         struct cap_msg_args arg;
2616 
2617                         doutc(cl, "%p %llx.%llx cap %p tid %llu %s\n",
2618                               inode, ceph_vinop(inode), cap, cf->tid,
2619                               ceph_cap_string(cf->caps));
2620                         __prep_cap(&arg, cap, CEPH_CAP_OP_FLUSH,
2621                                          (cf->tid < last_snap_flush ?
2622                                           CEPH_CLIENT_CAPS_PENDING_CAPSNAP : 0),
2623                                           __ceph_caps_used(ci),
2624                                           __ceph_caps_wanted(ci),
2625                                           (cap->issued | cap->implemented),
2626                                           cf->caps, cf->tid, oldest_flush_tid);
2627                         spin_unlock(&ci->i_ceph_lock);
2628                         __send_cap(&arg, ci);
2629                 } else {
2630                         struct ceph_cap_snap *capsnap =
2631                                         container_of(cf, struct ceph_cap_snap,
2632                                                     cap_flush);
2633                         doutc(cl, "%p %llx.%llx capsnap %p tid %llu %s\n",
2634                               inode, ceph_vinop(inode), capsnap, cf->tid,
2635                               ceph_cap_string(capsnap->dirty));
2636 
2637                         refcount_inc(&capsnap->nref);
2638                         spin_unlock(&ci->i_ceph_lock);
2639 
2640                         ret = __send_flush_snap(inode, session, capsnap, cap->mseq,
2641                                                 oldest_flush_tid);
2642                         if (ret < 0) {
2643                                 pr_err_client(cl, "error sending cap flushsnap,"
2644                                               " %p %llx.%llx tid %llu follows %llu\n",
2645                                               inode, ceph_vinop(inode), cf->tid,
2646                                               capsnap->follows);
2647                         }
2648 
2649                         ceph_put_cap_snap(capsnap);
2650                 }
2651 
2652                 spin_lock(&ci->i_ceph_lock);
2653         }
2654 }
2655 
2656 void ceph_early_kick_flushing_caps(struct ceph_mds_client *mdsc,
2657                                    struct ceph_mds_session *session)
2658 {
2659         struct ceph_client *cl = mdsc->fsc->client;
2660         struct ceph_inode_info *ci;
2661         struct ceph_cap *cap;
2662         u64 oldest_flush_tid;
2663 
2664         doutc(cl, "mds%d\n", session->s_mds);
2665 
2666         spin_lock(&mdsc->cap_dirty_lock);
2667         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2668         spin_unlock(&mdsc->cap_dirty_lock);
2669 
2670         list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
2671                 struct inode *inode = &ci->netfs.inode;
2672 
2673                 spin_lock(&ci->i_ceph_lock);
2674                 cap = ci->i_auth_cap;
2675                 if (!(cap && cap->session == session)) {
2676                         pr_err_client(cl, "%p %llx.%llx auth cap %p not mds%d ???\n",
2677                                       inode, ceph_vinop(inode), cap,
2678                                       session->s_mds);
2679                         spin_unlock(&ci->i_ceph_lock);
2680                         continue;
2681                 }
2682 
2683 
2684                 /*
2685                  * if flushing caps were revoked, we re-send the cap flush
2686                  * in client reconnect stage. This guarantees MDS * processes
2687                  * the cap flush message before issuing the flushing caps to
2688                  * other client.
2689                  */
2690                 if ((cap->issued & ci->i_flushing_caps) !=
2691                     ci->i_flushing_caps) {
2692                         /* encode_caps_cb() also will reset these sequence
2693                          * numbers. make sure sequence numbers in cap flush
2694                          * message match later reconnect message */
2695                         cap->seq = 0;
2696                         cap->issue_seq = 0;
2697                         cap->mseq = 0;
2698                         __kick_flushing_caps(mdsc, session, ci,
2699                                              oldest_flush_tid);
2700                 } else {
2701                         ci->i_ceph_flags |= CEPH_I_KICK_FLUSH;
2702                 }
2703 
2704                 spin_unlock(&ci->i_ceph_lock);
2705         }
2706 }
2707 
2708 void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
2709                              struct ceph_mds_session *session)
2710 {
2711         struct ceph_client *cl = mdsc->fsc->client;
2712         struct ceph_inode_info *ci;
2713         struct ceph_cap *cap;
2714         u64 oldest_flush_tid;
2715 
2716         lockdep_assert_held(&session->s_mutex);
2717 
2718         doutc(cl, "mds%d\n", session->s_mds);
2719 
2720         spin_lock(&mdsc->cap_dirty_lock);
2721         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2722         spin_unlock(&mdsc->cap_dirty_lock);
2723 
2724         list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
2725                 struct inode *inode = &ci->netfs.inode;
2726 
2727                 spin_lock(&ci->i_ceph_lock);
2728                 cap = ci->i_auth_cap;
2729                 if (!(cap && cap->session == session)) {
2730                         pr_err_client(cl, "%p %llx.%llx auth cap %p not mds%d ???\n",
2731                                       inode, ceph_vinop(inode), cap,
2732                                       session->s_mds);
2733                         spin_unlock(&ci->i_ceph_lock);
2734                         continue;
2735                 }
2736                 if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH) {
2737                         __kick_flushing_caps(mdsc, session, ci,
2738                                              oldest_flush_tid);
2739                 }
2740                 spin_unlock(&ci->i_ceph_lock);
2741         }
2742 }
2743 
2744 void ceph_kick_flushing_inode_caps(struct ceph_mds_session *session,
2745                                    struct ceph_inode_info *ci)
2746 {
2747         struct ceph_mds_client *mdsc = session->s_mdsc;
2748         struct ceph_cap *cap = ci->i_auth_cap;
2749         struct inode *inode = &ci->netfs.inode;
2750 
2751         lockdep_assert_held(&ci->i_ceph_lock);
2752 
2753         doutc(mdsc->fsc->client, "%p %llx.%llx flushing %s\n",
2754               inode, ceph_vinop(inode),
2755               ceph_cap_string(ci->i_flushing_caps));
2756 
2757         if (!list_empty(&ci->i_cap_flush_list)) {
2758                 u64 oldest_flush_tid;
2759                 spin_lock(&mdsc->cap_dirty_lock);
2760                 list_move_tail(&ci->i_flushing_item,
2761                                &cap->session->s_cap_flushing);
2762                 oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2763                 spin_unlock(&mdsc->cap_dirty_lock);
2764 
2765                 __kick_flushing_caps(mdsc, session, ci, oldest_flush_tid);
2766         }
2767 }
2768 
2769 
2770 /*
2771  * Take references to capabilities we hold, so that we don't release
2772  * them to the MDS prematurely.
2773  */
2774 void ceph_take_cap_refs(struct ceph_inode_info *ci, int got,
2775                             bool snap_rwsem_locked)
2776 {
2777         struct inode *inode = &ci->netfs.inode;
2778         struct ceph_client *cl = ceph_inode_to_client(inode);
2779 
2780         lockdep_assert_held(&ci->i_ceph_lock);
2781 
2782         if (got & CEPH_CAP_PIN)
2783                 ci->i_pin_ref++;
2784         if (got & CEPH_CAP_FILE_RD)
2785                 ci->i_rd_ref++;
2786         if (got & CEPH_CAP_FILE_CACHE)
2787                 ci->i_rdcache_ref++;
2788         if (got & CEPH_CAP_FILE_EXCL)
2789                 ci->i_fx_ref++;
2790         if (got & CEPH_CAP_FILE_WR) {
2791                 if (ci->i_wr_ref == 0 && !ci->i_head_snapc) {
2792                         BUG_ON(!snap_rwsem_locked);
2793                         ci->i_head_snapc = ceph_get_snap_context(
2794                                         ci->i_snap_realm->cached_context);
2795                 }
2796                 ci->i_wr_ref++;
2797         }
2798         if (got & CEPH_CAP_FILE_BUFFER) {
2799                 if (ci->i_wb_ref == 0)
2800                         ihold(inode);
2801                 ci->i_wb_ref++;
2802                 doutc(cl, "%p %llx.%llx wb %d -> %d (?)\n", inode,
2803                       ceph_vinop(inode), ci->i_wb_ref-1, ci->i_wb_ref);
2804         }
2805 }
2806 
2807 /*
2808  * Try to grab cap references.  Specify those refs we @want, and the
2809  * minimal set we @need.  Also include the larger offset we are writing
2810  * to (when applicable), and check against max_size here as well.
2811  * Note that caller is responsible for ensuring max_size increases are
2812  * requested from the MDS.
2813  *
2814  * Returns 0 if caps were not able to be acquired (yet), 1 if succeed,
2815  * or a negative error code. There are 3 speical error codes:
2816  *  -EAGAIN:  need to sleep but non-blocking is specified
2817  *  -EFBIG:   ask caller to call check_max_size() and try again.
2818  *  -EUCLEAN: ask caller to call ceph_renew_caps() and try again.
2819  */
2820 enum {
2821         /* first 8 bits are reserved for CEPH_FILE_MODE_FOO */
2822         NON_BLOCKING    = (1 << 8),
2823         CHECK_FILELOCK  = (1 << 9),
2824 };
2825 
2826 static int try_get_cap_refs(struct inode *inode, int need, int want,
2827                             loff_t endoff, int flags, int *got)
2828 {
2829         struct ceph_inode_info *ci = ceph_inode(inode);
2830         struct ceph_mds_client *mdsc = ceph_inode_to_fs_client(inode)->mdsc;
2831         struct ceph_client *cl = ceph_inode_to_client(inode);
2832         int ret = 0;
2833         int have, implemented;
2834         bool snap_rwsem_locked = false;
2835 
2836         doutc(cl, "%p %llx.%llx need %s want %s\n", inode,
2837               ceph_vinop(inode), ceph_cap_string(need),
2838               ceph_cap_string(want));
2839 
2840 again:
2841         spin_lock(&ci->i_ceph_lock);
2842 
2843         if ((flags & CHECK_FILELOCK) &&
2844             (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK)) {
2845                 doutc(cl, "%p %llx.%llx error filelock\n", inode,
2846                       ceph_vinop(inode));
2847                 ret = -EIO;
2848                 goto out_unlock;
2849         }
2850 
2851         /* finish pending truncate */
2852         while (ci->i_truncate_pending) {
2853                 spin_unlock(&ci->i_ceph_lock);
2854                 if (snap_rwsem_locked) {
2855                         up_read(&mdsc->snap_rwsem);
2856                         snap_rwsem_locked = false;
2857                 }
2858                 __ceph_do_pending_vmtruncate(inode);
2859                 spin_lock(&ci->i_ceph_lock);
2860         }
2861 
2862         have = __ceph_caps_issued(ci, &implemented);
2863 
2864         if (have & need & CEPH_CAP_FILE_WR) {
2865                 if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
2866                         doutc(cl, "%p %llx.%llx endoff %llu > maxsize %llu\n",
2867                               inode, ceph_vinop(inode), endoff, ci->i_max_size);
2868                         if (endoff > ci->i_requested_max_size)
2869                                 ret = ci->i_auth_cap ? -EFBIG : -EUCLEAN;
2870                         goto out_unlock;
2871                 }
2872                 /*
2873                  * If a sync write is in progress, we must wait, so that we
2874                  * can get a final snapshot value for size+mtime.
2875                  */
2876                 if (__ceph_have_pending_cap_snap(ci)) {
2877                         doutc(cl, "%p %llx.%llx cap_snap_pending\n", inode,
2878                               ceph_vinop(inode));
2879                         goto out_unlock;
2880                 }
2881         }
2882 
2883         if ((have & need) == need) {
2884                 /*
2885                  * Look at (implemented & ~have & not) so that we keep waiting
2886                  * on transition from wanted -> needed caps.  This is needed
2887                  * for WRBUFFER|WR -> WR to avoid a new WR sync write from
2888                  * going before a prior buffered writeback happens.
2889                  *
2890                  * For RDCACHE|RD -> RD, there is not need to wait and we can
2891                  * just exclude the revoking caps and force to sync read.
2892                  */
2893                 int not = want & ~(have & need);
2894                 int revoking = implemented & ~have;
2895                 int exclude = revoking & not;
2896                 doutc(cl, "%p %llx.%llx have %s but not %s (revoking %s)\n",
2897                       inode, ceph_vinop(inode), ceph_cap_string(have),
2898                       ceph_cap_string(not), ceph_cap_string(revoking));
2899                 if (!exclude || !(exclude & CEPH_CAP_FILE_BUFFER)) {
2900                         if (!snap_rwsem_locked &&
2901                             !ci->i_head_snapc &&
2902                             (need & CEPH_CAP_FILE_WR)) {
2903                                 if (!down_read_trylock(&mdsc->snap_rwsem)) {
2904                                         /*
2905                                          * we can not call down_read() when
2906                                          * task isn't in TASK_RUNNING state
2907                                          */
2908                                         if (flags & NON_BLOCKING) {
2909                                                 ret = -EAGAIN;
2910                                                 goto out_unlock;
2911                                         }
2912 
2913                                         spin_unlock(&ci->i_ceph_lock);
2914                                         down_read(&mdsc->snap_rwsem);
2915                                         snap_rwsem_locked = true;
2916                                         goto again;
2917                                 }
2918                                 snap_rwsem_locked = true;
2919                         }
2920                         if ((have & want) == want)
2921                                 *got = need | (want & ~exclude);
2922                         else
2923                                 *got = need;
2924                         ceph_take_cap_refs(ci, *got, true);
2925                         ret = 1;
2926                 }
2927         } else {
2928                 int session_readonly = false;
2929                 int mds_wanted;
2930                 if (ci->i_auth_cap &&
2931                     (need & (CEPH_CAP_FILE_WR | CEPH_CAP_FILE_EXCL))) {
2932                         struct ceph_mds_session *s = ci->i_auth_cap->session;
2933                         spin_lock(&s->s_cap_lock);
2934                         session_readonly = s->s_readonly;
2935                         spin_unlock(&s->s_cap_lock);
2936                 }
2937                 if (session_readonly) {
2938                         doutc(cl, "%p %llx.%llx need %s but mds%d readonly\n",
2939                               inode, ceph_vinop(inode), ceph_cap_string(need),
2940                               ci->i_auth_cap->mds);
2941                         ret = -EROFS;
2942                         goto out_unlock;
2943                 }
2944 
2945                 if (ceph_inode_is_shutdown(inode)) {
2946                         doutc(cl, "%p %llx.%llx inode is shutdown\n",
2947                               inode, ceph_vinop(inode));
2948                         ret = -ESTALE;
2949                         goto out_unlock;
2950                 }
2951                 mds_wanted = __ceph_caps_mds_wanted(ci, false);
2952                 if (need & ~mds_wanted) {
2953                         doutc(cl, "%p %llx.%llx need %s > mds_wanted %s\n",
2954                               inode, ceph_vinop(inode), ceph_cap_string(need),
2955                               ceph_cap_string(mds_wanted));
2956                         ret = -EUCLEAN;
2957                         goto out_unlock;
2958                 }
2959 
2960                 doutc(cl, "%p %llx.%llx have %s need %s\n", inode,
2961                       ceph_vinop(inode), ceph_cap_string(have),
2962                       ceph_cap_string(need));
2963         }
2964 out_unlock:
2965 
2966         __ceph_touch_fmode(ci, mdsc, flags);
2967 
2968         spin_unlock(&ci->i_ceph_lock);
2969         if (snap_rwsem_locked)
2970                 up_read(&mdsc->snap_rwsem);
2971 
2972         if (!ret)
2973                 ceph_update_cap_mis(&mdsc->metric);
2974         else if (ret == 1)
2975                 ceph_update_cap_hit(&mdsc->metric);
2976 
2977         doutc(cl, "%p %llx.%llx ret %d got %s\n", inode,
2978               ceph_vinop(inode), ret, ceph_cap_string(*got));
2979         return ret;
2980 }
2981 
2982 /*
2983  * Check the offset we are writing up to against our current
2984  * max_size.  If necessary, tell the MDS we want to write to
2985  * a larger offset.
2986  */
2987 static void check_max_size(struct inode *inode, loff_t endoff)
2988 {
2989         struct ceph_inode_info *ci = ceph_inode(inode);
2990         struct ceph_client *cl = ceph_inode_to_client(inode);
2991         int check = 0;
2992 
2993         /* do we need to explicitly request a larger max_size? */
2994         spin_lock(&ci->i_ceph_lock);
2995         if (endoff >= ci->i_max_size && endoff > ci->i_wanted_max_size) {
2996                 doutc(cl, "write %p %llx.%llx at large endoff %llu, req max_size\n",
2997                       inode, ceph_vinop(inode), endoff);
2998                 ci->i_wanted_max_size = endoff;
2999         }
3000         /* duplicate ceph_check_caps()'s logic */
3001         if (ci->i_auth_cap &&
3002             (ci->i_auth_cap->issued & CEPH_CAP_FILE_WR) &&
3003             ci->i_wanted_max_size > ci->i_max_size &&
3004             ci->i_wanted_max_size > ci->i_requested_max_size)
3005                 check = 1;
3006         spin_unlock(&ci->i_ceph_lock);
3007         if (check)
3008                 ceph_check_caps(ci, CHECK_CAPS_AUTHONLY);
3009 }
3010 
3011 static inline int get_used_fmode(int caps)
3012 {
3013         int fmode = 0;
3014         if (caps & CEPH_CAP_FILE_RD)
3015                 fmode |= CEPH_FILE_MODE_RD;
3016         if (caps & CEPH_CAP_FILE_WR)
3017                 fmode |= CEPH_FILE_MODE_WR;
3018         return fmode;
3019 }
3020 
3021 int ceph_try_get_caps(struct inode *inode, int need, int want,
3022                       bool nonblock, int *got)
3023 {
3024         int ret, flags;
3025 
3026         BUG_ON(need & ~CEPH_CAP_FILE_RD);
3027         BUG_ON(want & ~(CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO |
3028                         CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_EXCL |
3029                         CEPH_CAP_ANY_DIR_OPS));
3030         if (need) {
3031                 ret = ceph_pool_perm_check(inode, need);
3032                 if (ret < 0)
3033                         return ret;
3034         }
3035 
3036         flags = get_used_fmode(need | want);
3037         if (nonblock)
3038                 flags |= NON_BLOCKING;
3039 
3040         ret = try_get_cap_refs(inode, need, want, 0, flags, got);
3041         /* three special error codes */
3042         if (ret == -EAGAIN || ret == -EFBIG || ret == -EUCLEAN)
3043                 ret = 0;
3044         return ret;
3045 }
3046 
3047 /*
3048  * Wait for caps, and take cap references.  If we can't get a WR cap
3049  * due to a small max_size, make sure we check_max_size (and possibly
3050  * ask the mds) so we don't get hung up indefinitely.
3051  */
3052 int __ceph_get_caps(struct inode *inode, struct ceph_file_info *fi, int need,
3053                     int want, loff_t endoff, int *got)
3054 {
3055         struct ceph_inode_info *ci = ceph_inode(inode);
3056         struct ceph_fs_client *fsc = ceph_inode_to_fs_client(inode);
3057         int ret, _got, flags;
3058 
3059         ret = ceph_pool_perm_check(inode, need);
3060         if (ret < 0)
3061                 return ret;
3062 
3063         if (fi && (fi->fmode & CEPH_FILE_MODE_WR) &&
3064             fi->filp_gen != READ_ONCE(fsc->filp_gen))
3065                 return -EBADF;
3066 
3067         flags = get_used_fmode(need | want);
3068 
3069         while (true) {
3070                 flags &= CEPH_FILE_MODE_MASK;
3071                 if (vfs_inode_has_locks(inode))
3072                         flags |= CHECK_FILELOCK;
3073                 _got = 0;
3074                 ret = try_get_cap_refs(inode, need, want, endoff,
3075                                        flags, &_got);
3076                 WARN_ON_ONCE(ret == -EAGAIN);
3077                 if (!ret) {
3078 #ifdef CONFIG_DEBUG_FS
3079                         struct ceph_mds_client *mdsc = fsc->mdsc;
3080                         struct cap_wait cw;
3081 #endif
3082                         DEFINE_WAIT_FUNC(wait, woken_wake_function);
3083 
3084 #ifdef CONFIG_DEBUG_FS
3085                         cw.ino = ceph_ino(inode);
3086                         cw.tgid = current->tgid;
3087                         cw.need = need;
3088                         cw.want = want;
3089 
3090                         spin_lock(&mdsc->caps_list_lock);
3091                         list_add(&cw.list, &mdsc->cap_wait_list);
3092                         spin_unlock(&mdsc->caps_list_lock);
3093 #endif
3094 
3095                         /* make sure used fmode not timeout */
3096                         ceph_get_fmode(ci, flags, FMODE_WAIT_BIAS);
3097                         add_wait_queue(&ci->i_cap_wq, &wait);
3098 
3099                         flags |= NON_BLOCKING;
3100                         while (!(ret = try_get_cap_refs(inode, need, want,
3101                                                         endoff, flags, &_got))) {
3102                                 if (signal_pending(current)) {
3103                                         ret = -ERESTARTSYS;
3104                                         break;
3105                                 }
3106                                 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
3107                         }
3108 
3109                         remove_wait_queue(&ci->i_cap_wq, &wait);
3110                         ceph_put_fmode(ci, flags, FMODE_WAIT_BIAS);
3111 
3112 #ifdef CONFIG_DEBUG_FS
3113                         spin_lock(&mdsc->caps_list_lock);
3114                         list_del(&cw.list);
3115                         spin_unlock(&mdsc->caps_list_lock);
3116 #endif
3117 
3118                         if (ret == -EAGAIN)
3119                                 continue;
3120                 }
3121 
3122                 if (fi && (fi->fmode & CEPH_FILE_MODE_WR) &&
3123                     fi->filp_gen != READ_ONCE(fsc->filp_gen)) {
3124                         if (ret >= 0 && _got)
3125                                 ceph_put_cap_refs(ci, _got);
3126                         return -EBADF;
3127                 }
3128 
3129                 if (ret < 0) {
3130                         if (ret == -EFBIG || ret == -EUCLEAN) {
3131                                 int ret2 = ceph_wait_on_async_create(inode);
3132                                 if (ret2 < 0)
3133                                         return ret2;
3134                         }
3135                         if (ret == -EFBIG) {
3136                                 check_max_size(inode, endoff);
3137                                 continue;
3138                         }
3139                         if (ret == -EUCLEAN) {
3140                                 /* session was killed, try renew caps */
3141                                 ret = ceph_renew_caps(inode, flags);
3142                                 if (ret == 0)
3143                                         continue;
3144                         }
3145                         return ret;
3146                 }
3147 
3148                 if (S_ISREG(ci->netfs.inode.i_mode) &&
3149                     ceph_has_inline_data(ci) &&
3150                     (_got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
3151                     i_size_read(inode) > 0) {
3152                         struct page *page =
3153                                 find_get_page(inode->i_mapping, 0);
3154                         if (page) {
3155                                 bool uptodate = PageUptodate(page);
3156 
3157                                 put_page(page);
3158                                 if (uptodate)
3159                                         break;
3160                         }
3161                         /*
3162                          * drop cap refs first because getattr while
3163                          * holding * caps refs can cause deadlock.
3164                          */
3165                         ceph_put_cap_refs(ci, _got);
3166                         _got = 0;
3167 
3168                         /*
3169                          * getattr request will bring inline data into
3170                          * page cache
3171                          */
3172                         ret = __ceph_do_getattr(inode, NULL,
3173                                                 CEPH_STAT_CAP_INLINE_DATA,
3174                                                 true);
3175                         if (ret < 0)
3176                                 return ret;
3177                         continue;
3178                 }
3179                 break;
3180         }
3181         *got = _got;
3182         return 0;
3183 }
3184 
3185 int ceph_get_caps(struct file *filp, int need, int want, loff_t endoff,
3186                   int *got)
3187 {
3188         struct ceph_file_info *fi = filp->private_data;
3189         struct inode *inode = file_inode(filp);
3190 
3191         return __ceph_get_caps(inode, fi, need, want, endoff, got);
3192 }
3193 
3194 /*
3195  * Take cap refs.  Caller must already know we hold at least one ref
3196  * on the caps in question or we don't know this is safe.
3197  */
3198 void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps)
3199 {
3200         spin_lock(&ci->i_ceph_lock);
3201         ceph_take_cap_refs(ci, caps, false);
3202         spin_unlock(&ci->i_ceph_lock);
3203 }
3204 
3205 
3206 /*
3207  * drop cap_snap that is not associated with any snapshot.
3208  * we don't need to send FLUSHSNAP message for it.
3209  */
3210 static int ceph_try_drop_cap_snap(struct ceph_inode_info *ci,
3211                                   struct ceph_cap_snap *capsnap)
3212 {
3213         struct inode *inode = &ci->netfs.inode;
3214         struct ceph_client *cl = ceph_inode_to_client(inode);
3215 
3216         if (!capsnap->need_flush &&
3217             !capsnap->writing && !capsnap->dirty_pages) {
3218                 doutc(cl, "%p follows %llu\n", capsnap, capsnap->follows);
3219                 BUG_ON(capsnap->cap_flush.tid > 0);
3220                 ceph_put_snap_context(capsnap->context);
3221                 if (!list_is_last(&capsnap->ci_item, &ci->i_cap_snaps))
3222                         ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
3223 
3224                 list_del(&capsnap->ci_item);
3225                 ceph_put_cap_snap(capsnap);
3226                 return 1;
3227         }
3228         return 0;
3229 }
3230 
3231 enum put_cap_refs_mode {
3232         PUT_CAP_REFS_SYNC = 0,
3233         PUT_CAP_REFS_ASYNC,
3234 };
3235 
3236 /*
3237  * Release cap refs.
3238  *
3239  * If we released the last ref on any given cap, call ceph_check_caps
3240  * to release (or schedule a release).
3241  *
3242  * If we are releasing a WR cap (from a sync write), finalize any affected
3243  * cap_snap, and wake up any waiters.
3244  */
3245 static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had,
3246                                 enum put_cap_refs_mode mode)
3247 {
3248         struct inode *inode = &ci->netfs.inode;
3249         struct ceph_client *cl = ceph_inode_to_client(inode);
3250         int last = 0, put = 0, flushsnaps = 0, wake = 0;
3251         bool check_flushsnaps = false;
3252 
3253         spin_lock(&ci->i_ceph_lock);
3254         if (had & CEPH_CAP_PIN)
3255                 --ci->i_pin_ref;
3256         if (had & CEPH_CAP_FILE_RD)
3257                 if (--ci->i_rd_ref == 0)
3258                         last++;
3259         if (had & CEPH_CAP_FILE_CACHE)
3260                 if (--ci->i_rdcache_ref == 0)
3261                         last++;
3262         if (had & CEPH_CAP_FILE_EXCL)
3263                 if (--ci->i_fx_ref == 0)
3264                         last++;
3265         if (had & CEPH_CAP_FILE_BUFFER) {
3266                 if (--ci->i_wb_ref == 0) {
3267                         last++;
3268                         /* put the ref held by ceph_take_cap_refs() */
3269                         put++;
3270                         check_flushsnaps = true;
3271                 }
3272                 doutc(cl, "%p %llx.%llx wb %d -> %d (?)\n", inode,
3273                       ceph_vinop(inode), ci->i_wb_ref+1, ci->i_wb_ref);
3274         }
3275         if (had & CEPH_CAP_FILE_WR) {
3276                 if (--ci->i_wr_ref == 0) {
3277                         /*
3278                          * The Fb caps will always be took and released
3279                          * together with the Fw caps.
3280                          */
3281                         WARN_ON_ONCE(ci->i_wb_ref);
3282 
3283                         last++;
3284                         check_flushsnaps = true;
3285                         if (ci->i_wrbuffer_ref_head == 0 &&
3286                             ci->i_dirty_caps == 0 &&
3287                             ci->i_flushing_caps == 0) {
3288                                 BUG_ON(!ci->i_head_snapc);
3289                                 ceph_put_snap_context(ci->i_head_snapc);
3290                                 ci->i_head_snapc = NULL;
3291                         }
3292                         /* see comment in __ceph_remove_cap() */
3293                         if (!__ceph_is_any_real_caps(ci) && ci->i_snap_realm)
3294                                 ceph_change_snap_realm(inode, NULL);
3295                 }
3296         }
3297         if (check_flushsnaps && __ceph_have_pending_cap_snap(ci)) {
3298                 struct ceph_cap_snap *capsnap =
3299                         list_last_entry(&ci->i_cap_snaps,
3300                                         struct ceph_cap_snap,
3301                                         ci_item);
3302 
3303                 capsnap->writing = 0;
3304                 if (ceph_try_drop_cap_snap(ci, capsnap))
3305                         /* put the ref held by ceph_queue_cap_snap() */
3306                         put++;
3307                 else if (__ceph_finish_cap_snap(ci, capsnap))
3308                         flushsnaps = 1;
3309                 wake = 1;
3310         }
3311         spin_unlock(&ci->i_ceph_lock);
3312 
3313         doutc(cl, "%p %llx.%llx had %s%s%s\n", inode, ceph_vinop(inode),
3314               ceph_cap_string(had), last ? " last" : "", put ? " put" : "");
3315 
3316         switch (mode) {
3317         case PUT_CAP_REFS_SYNC:
3318                 if (last)
3319                         ceph_check_caps(ci, 0);
3320                 else if (flushsnaps)
3321                         ceph_flush_snaps(ci, NULL);
3322                 break;
3323         case PUT_CAP_REFS_ASYNC:
3324                 if (last)
3325                         ceph_queue_check_caps(inode);
3326                 else if (flushsnaps)
3327                         ceph_queue_flush_snaps(inode);
3328                 break;
3329         default:
3330                 break;
3331         }
3332         if (wake)
3333                 wake_up_all(&ci->i_cap_wq);
3334         while (put-- > 0)
3335                 iput(inode);
3336 }
3337 
3338 void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
3339 {
3340         __ceph_put_cap_refs(ci, had, PUT_CAP_REFS_SYNC);
3341 }
3342 
3343 void ceph_put_cap_refs_async(struct ceph_inode_info *ci, int had)
3344 {
3345         __ceph_put_cap_refs(ci, had, PUT_CAP_REFS_ASYNC);
3346 }
3347 
3348 /*
3349  * Release @nr WRBUFFER refs on dirty pages for the given @snapc snap
3350  * context.  Adjust per-snap dirty page accounting as appropriate.
3351  * Once all dirty data for a cap_snap is flushed, flush snapped file
3352  * metadata back to the MDS.  If we dropped the last ref, call
3353  * ceph_check_caps.
3354  */
3355 void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
3356                                 struct ceph_snap_context *snapc)
3357 {
3358         struct inode *inode = &ci->netfs.inode;
3359         struct ceph_client *cl = ceph_inode_to_client(inode);
3360         struct ceph_cap_snap *capsnap = NULL, *iter;
3361         int put = 0;
3362         bool last = false;
3363         bool flush_snaps = false;
3364         bool complete_capsnap = false;
3365 
3366         spin_lock(&ci->i_ceph_lock);
3367         ci->i_wrbuffer_ref -= nr;
3368         if (ci->i_wrbuffer_ref == 0) {
3369                 last = true;
3370                 put++;
3371         }
3372 
3373         if (ci->i_head_snapc == snapc) {
3374                 ci->i_wrbuffer_ref_head -= nr;
3375                 if (ci->i_wrbuffer_ref_head == 0 &&
3376                     ci->i_wr_ref == 0 &&
3377                     ci->i_dirty_caps == 0 &&
3378                     ci->i_flushing_caps == 0) {
3379                         BUG_ON(!ci->i_head_snapc);
3380                         ceph_put_snap_context(ci->i_head_snapc);
3381                         ci->i_head_snapc = NULL;
3382                 }
3383                 doutc(cl, "on %p %llx.%llx head %d/%d -> %d/%d %s\n",
3384                       inode, ceph_vinop(inode), ci->i_wrbuffer_ref+nr,
3385                       ci->i_wrbuffer_ref_head+nr, ci->i_wrbuffer_ref,
3386                       ci->i_wrbuffer_ref_head, last ? " LAST" : "");
3387         } else {
3388                 list_for_each_entry(iter, &ci->i_cap_snaps, ci_item) {
3389                         if (iter->context == snapc) {
3390                                 capsnap = iter;
3391                                 break;
3392                         }
3393                 }
3394 
3395                 if (!capsnap) {
3396                         /*
3397                          * The capsnap should already be removed when removing
3398                          * auth cap in the case of a forced unmount.
3399                          */
3400                         WARN_ON_ONCE(ci->i_auth_cap);
3401                         goto unlock;
3402                 }
3403 
3404                 capsnap->dirty_pages -= nr;
3405                 if (capsnap->dirty_pages == 0) {
3406                         complete_capsnap = true;
3407                         if (!capsnap->writing) {
3408                                 if (ceph_try_drop_cap_snap(ci, capsnap)) {
3409                                         put++;
3410                                 } else {
3411                                         ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
3412                                         flush_snaps = true;
3413                                 }
3414                         }
3415                 }
3416                 doutc(cl, "%p %llx.%llx cap_snap %p snap %lld %d/%d -> %d/%d %s%s\n",
3417                       inode, ceph_vinop(inode), capsnap, capsnap->context->seq,
3418                       ci->i_wrbuffer_ref+nr, capsnap->dirty_pages + nr,
3419                       ci->i_wrbuffer_ref, capsnap->dirty_pages,
3420                       last ? " (wrbuffer last)" : "",
3421                       complete_capsnap ? " (complete capsnap)" : "");
3422         }
3423 
3424 unlock:
3425         spin_unlock(&ci->i_ceph_lock);
3426 
3427         if (last) {
3428                 ceph_check_caps(ci, 0);
3429         } else if (flush_snaps) {
3430                 ceph_flush_snaps(ci, NULL);
3431         }
3432         if (complete_capsnap)
3433                 wake_up_all(&ci->i_cap_wq);
3434         while (put-- > 0) {
3435                 iput(inode);
3436         }
3437 }
3438 
3439 /*
3440  * Invalidate unlinked inode's aliases, so we can drop the inode ASAP.
3441  */
3442 static void invalidate_aliases(struct inode *inode)
3443 {
3444         struct ceph_client *cl = ceph_inode_to_client(inode);
3445         struct dentry *dn, *prev = NULL;
3446 
3447         doutc(cl, "%p %llx.%llx\n", inode, ceph_vinop(inode));
3448         d_prune_aliases(inode);
3449         /*
3450          * For non-directory inode, d_find_alias() only returns
3451          * hashed dentry. After calling d_invalidate(), the
3452          * dentry becomes unhashed.
3453          *
3454          * For directory inode, d_find_alias() can return
3455          * unhashed dentry. But directory inode should have
3456          * one alias at most.
3457          */
3458         while ((dn = d_find_alias(inode))) {
3459                 if (dn == prev) {
3460                         dput(dn);
3461                         break;
3462                 }
3463                 d_invalidate(dn);
3464                 if (prev)
3465                         dput(prev);
3466                 prev = dn;
3467         }
3468         if (prev)
3469                 dput(prev);
3470 }
3471 
3472 struct cap_extra_info {
3473         struct ceph_string *pool_ns;
3474         /* inline data */
3475         u64 inline_version;
3476         void *inline_data;
3477         u32 inline_len;
3478         /* dirstat */
3479         bool dirstat_valid;
3480         u64 nfiles;
3481         u64 nsubdirs;
3482         u64 change_attr;
3483         /* currently issued */
3484         int issued;
3485         struct timespec64 btime;
3486         u8 *fscrypt_auth;
3487         u32 fscrypt_auth_len;
3488         u64 fscrypt_file_size;
3489 };
3490 
3491 /*
3492  * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
3493  * actually be a revocation if it specifies a smaller cap set.)
3494  *
3495  * caller holds s_mutex and i_ceph_lock, we drop both.
3496  */
3497 static void handle_cap_grant(struct inode *inode,
3498                              struct ceph_mds_session *session,
3499                              struct ceph_cap *cap,
3500                              struct ceph_mds_caps *grant,
3501                              struct ceph_buffer *xattr_buf,
3502                              struct cap_extra_info *extra_info)
3503         __releases(ci->i_ceph_lock)
3504         __releases(session->s_mdsc->snap_rwsem)
3505 {
3506         struct ceph_client *cl = ceph_inode_to_client(inode);
3507         struct ceph_inode_info *ci = ceph_inode(inode);
3508         int seq = le32_to_cpu(grant->seq);
3509         int newcaps = le32_to_cpu(grant->caps);
3510         int used, wanted, dirty;
3511         u64 size = le64_to_cpu(grant->size);
3512         u64 max_size = le64_to_cpu(grant->max_size);
3513         unsigned char check_caps = 0;
3514         bool was_stale = cap->cap_gen < atomic_read(&session->s_cap_gen);
3515         bool wake = false;
3516         bool writeback = false;
3517         bool queue_trunc = false;
3518         bool queue_invalidate = false;
3519         bool deleted_inode = false;
3520         bool fill_inline = false;
3521         bool revoke_wait = false;
3522         int flags = 0;
3523 
3524         /*
3525          * If there is at least one crypto block then we'll trust
3526          * fscrypt_file_size. If the real length of the file is 0, then
3527          * ignore it (it has probably been truncated down to 0 by the MDS).
3528          */
3529         if (IS_ENCRYPTED(inode) && size)
3530                 size = extra_info->fscrypt_file_size;
3531 
3532         doutc(cl, "%p %llx.%llx cap %p mds%d seq %d %s\n", inode,
3533               ceph_vinop(inode), cap, session->s_mds, seq,
3534               ceph_cap_string(newcaps));
3535         doutc(cl, " size %llu max_size %llu, i_size %llu\n", size,
3536               max_size, i_size_read(inode));
3537 
3538 
3539         /*
3540          * If CACHE is being revoked, and we have no dirty buffers,
3541          * try to invalidate (once).  (If there are dirty buffers, we
3542          * will invalidate _after_ writeback.)
3543          */
3544         if (S_ISREG(inode->i_mode) && /* don't invalidate readdir cache */
3545             ((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
3546             (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
3547             !(ci->i_wrbuffer_ref || ci->i_wb_ref)) {
3548                 if (try_nonblocking_invalidate(inode)) {
3549                         /* there were locked pages.. invalidate later
3550                            in a separate thread. */
3551                         if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
3552                                 queue_invalidate = true;
3553                                 ci->i_rdcache_revoking = ci->i_rdcache_gen;
3554                         }
3555                 }
3556         }
3557 
3558         if (was_stale)
3559                 cap->issued = cap->implemented = CEPH_CAP_PIN;
3560 
3561         /*
3562          * auth mds of the inode changed. we received the cap export message,
3563          * but still haven't received the cap import message. handle_cap_export
3564          * updated the new auth MDS' cap.
3565          *
3566          * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing a message
3567          * that was sent before the cap import message. So don't remove caps.
3568          */
3569         if (ceph_seq_cmp(seq, cap->seq) <= 0) {
3570                 WARN_ON(cap != ci->i_auth_cap);
3571                 WARN_ON(cap->cap_id != le64_to_cpu(grant->cap_id));
3572                 seq = cap->seq;
3573                 newcaps |= cap->issued;
3574         }
3575 
3576         /* side effects now are allowed */
3577         cap->cap_gen = atomic_read(&session->s_cap_gen);
3578         cap->seq = seq;
3579 
3580         __check_cap_issue(ci, cap, newcaps);
3581 
3582         inode_set_max_iversion_raw(inode, extra_info->change_attr);
3583 
3584         if ((newcaps & CEPH_CAP_AUTH_SHARED) &&
3585             (extra_info->issued & CEPH_CAP_AUTH_EXCL) == 0) {
3586                 umode_t mode = le32_to_cpu(grant->mode);
3587 
3588                 if (inode_wrong_type(inode, mode))
3589                         pr_warn_once("inode type changed! (ino %llx.%llx is 0%o, mds says 0%o)\n",
3590                                      ceph_vinop(inode), inode->i_mode, mode);
3591                 else
3592                         inode->i_mode = mode;
3593                 inode->i_uid = make_kuid(&init_user_ns, le32_to_cpu(grant->uid));
3594                 inode->i_gid = make_kgid(&init_user_ns, le32_to_cpu(grant->gid));
3595                 ci->i_btime = extra_info->btime;
3596                 doutc(cl, "%p %llx.%llx mode 0%o uid.gid %d.%d\n", inode,
3597                       ceph_vinop(inode), inode->i_mode,
3598                       from_kuid(&init_user_ns, inode->i_uid),
3599                       from_kgid(&init_user_ns, inode->i_gid));
3600 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
3601                 if (ci->fscrypt_auth_len != extra_info->fscrypt_auth_len ||
3602                     memcmp(ci->fscrypt_auth, extra_info->fscrypt_auth,
3603                            ci->fscrypt_auth_len))
3604                         pr_warn_ratelimited_client(cl,
3605                                 "cap grant attempt to change fscrypt_auth on non-I_NEW inode (old len %d new len %d)\n",
3606                                 ci->fscrypt_auth_len,
3607                                 extra_info->fscrypt_auth_len);
3608 #endif
3609         }
3610 
3611         if ((newcaps & CEPH_CAP_LINK_SHARED) &&
3612             (extra_info->issued & CEPH_CAP_LINK_EXCL) == 0) {
3613                 set_nlink(inode, le32_to_cpu(grant->nlink));
3614                 if (inode->i_nlink == 0)
3615                         deleted_inode = true;
3616         }
3617 
3618         if ((extra_info->issued & CEPH_CAP_XATTR_EXCL) == 0 &&
3619             grant->xattr_len) {
3620                 int len = le32_to_cpu(grant->xattr_len);
3621                 u64 version = le64_to_cpu(grant->xattr_version);
3622 
3623                 if (version > ci->i_xattrs.version) {
3624                         doutc(cl, " got new xattrs v%llu on %p %llx.%llx len %d\n",
3625                               version, inode, ceph_vinop(inode), len);
3626                         if (ci->i_xattrs.blob)
3627                                 ceph_buffer_put(ci->i_xattrs.blob);
3628                         ci->i_xattrs.blob = ceph_buffer_get(xattr_buf);
3629                         ci->i_xattrs.version = version;
3630                         ceph_forget_all_cached_acls(inode);
3631                         ceph_security_invalidate_secctx(inode);
3632                 }
3633         }
3634 
3635         if (newcaps & CEPH_CAP_ANY_RD) {
3636                 struct timespec64 mtime, atime, ctime;
3637                 /* ctime/mtime/atime? */
3638                 ceph_decode_timespec64(&mtime, &grant->mtime);
3639                 ceph_decode_timespec64(&atime, &grant->atime);
3640                 ceph_decode_timespec64(&ctime, &grant->ctime);
3641                 ceph_fill_file_time(inode, extra_info->issued,
3642                                     le32_to_cpu(grant->time_warp_seq),
3643                                     &ctime, &mtime, &atime);
3644         }
3645 
3646         if ((newcaps & CEPH_CAP_FILE_SHARED) && extra_info->dirstat_valid) {
3647                 ci->i_files = extra_info->nfiles;
3648                 ci->i_subdirs = extra_info->nsubdirs;
3649         }
3650 
3651         if (newcaps & (CEPH_CAP_ANY_FILE_RD | CEPH_CAP_ANY_FILE_WR)) {
3652                 /* file layout may have changed */
3653                 s64 old_pool = ci->i_layout.pool_id;
3654                 struct ceph_string *old_ns;
3655 
3656                 ceph_file_layout_from_legacy(&ci->i_layout, &grant->layout);
3657                 old_ns = rcu_dereference_protected(ci->i_layout.pool_ns,
3658                                         lockdep_is_held(&ci->i_ceph_lock));
3659                 rcu_assign_pointer(ci->i_layout.pool_ns, extra_info->pool_ns);
3660 
3661                 if (ci->i_layout.pool_id != old_pool ||
3662                     extra_info->pool_ns != old_ns)
3663                         ci->i_ceph_flags &= ~CEPH_I_POOL_PERM;
3664 
3665                 extra_info->pool_ns = old_ns;
3666 
3667                 /* size/truncate_seq? */
3668                 queue_trunc = ceph_fill_file_size(inode, extra_info->issued,
3669                                         le32_to_cpu(grant->truncate_seq),
3670                                         le64_to_cpu(grant->truncate_size),
3671                                         size);
3672         }
3673 
3674         if (ci->i_auth_cap == cap && (newcaps & CEPH_CAP_ANY_FILE_WR)) {
3675                 if (max_size != ci->i_max_size) {
3676                         doutc(cl, "max_size %lld -> %llu\n", ci->i_max_size,
3677                               max_size);
3678                         ci->i_max_size = max_size;
3679                         if (max_size >= ci->i_wanted_max_size) {
3680                                 ci->i_wanted_max_size = 0;  /* reset */
3681                                 ci->i_requested_max_size = 0;
3682                         }
3683                         wake = true;
3684                 }
3685         }
3686 
3687         /* check cap bits */
3688         wanted = __ceph_caps_wanted(ci);
3689         used = __ceph_caps_used(ci);
3690         dirty = __ceph_caps_dirty(ci);
3691         doutc(cl, " my wanted = %s, used = %s, dirty %s\n",
3692               ceph_cap_string(wanted), ceph_cap_string(used),
3693               ceph_cap_string(dirty));
3694 
3695         if ((was_stale || le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) &&
3696             (wanted & ~(cap->mds_wanted | newcaps))) {
3697                 /*
3698                  * If mds is importing cap, prior cap messages that update
3699                  * 'wanted' may get dropped by mds (migrate seq mismatch).
3700                  *
3701                  * We don't send cap message to update 'wanted' if what we
3702                  * want are already issued. If mds revokes caps, cap message
3703                  * that releases caps also tells mds what we want. But if
3704                  * caps got revoked by mds forcedly (session stale). We may
3705                  * haven't told mds what we want.
3706                  */
3707                 check_caps = 1;
3708         }
3709 
3710         /* revocation, grant, or no-op? */
3711         if (cap->issued & ~newcaps) {
3712                 int revoking = cap->issued & ~newcaps;
3713 
3714                 doutc(cl, "revocation: %s -> %s (revoking %s)\n",
3715                       ceph_cap_string(cap->issued), ceph_cap_string(newcaps),
3716                       ceph_cap_string(revoking));
3717                 if (S_ISREG(inode->i_mode) &&
3718                     (revoking & used & CEPH_CAP_FILE_BUFFER)) {
3719                         writeback = true;  /* initiate writeback; will delay ack */
3720                         revoke_wait = true;
3721                 } else if (queue_invalidate &&
3722                          revoking == CEPH_CAP_FILE_CACHE &&
3723                          (newcaps & CEPH_CAP_FILE_LAZYIO) == 0) {
3724                         revoke_wait = true; /* do nothing yet, invalidation will be queued */
3725                 } else if (cap == ci->i_auth_cap) {
3726                         check_caps = 1; /* check auth cap only */
3727                 } else {
3728                         check_caps = 2; /* check all caps */
3729                 }
3730                 /* If there is new caps, try to wake up the waiters */
3731                 if (~cap->issued & newcaps)
3732                         wake = true;
3733                 cap->issued = newcaps;
3734                 cap->implemented |= newcaps;
3735         } else if (cap->issued == newcaps) {
3736                 doutc(cl, "caps unchanged: %s -> %s\n",
3737                       ceph_cap_string(cap->issued),
3738                       ceph_cap_string(newcaps));
3739         } else {
3740                 doutc(cl, "grant: %s -> %s\n", ceph_cap_string(cap->issued),
3741                       ceph_cap_string(newcaps));
3742                 /* non-auth MDS is revoking the newly grant caps ? */
3743                 if (cap == ci->i_auth_cap &&
3744                     __ceph_caps_revoking_other(ci, cap, newcaps))
3745                     check_caps = 2;
3746 
3747                 cap->issued = newcaps;
3748                 cap->implemented |= newcaps; /* add bits only, to
3749                                               * avoid stepping on a
3750                                               * pending revocation */
3751                 wake = true;
3752         }
3753         BUG_ON(cap->issued & ~cap->implemented);
3754 
3755         /* don't let check_caps skip sending a response to MDS for revoke msgs */
3756         if (!revoke_wait && le32_to_cpu(grant->op) == CEPH_CAP_OP_REVOKE) {
3757                 cap->mds_wanted = 0;
3758                 flags |= CHECK_CAPS_FLUSH_FORCE;
3759                 if (cap == ci->i_auth_cap)
3760                         check_caps = 1; /* check auth cap only */
3761                 else
3762                         check_caps = 2; /* check all caps */
3763         }
3764 
3765         if (extra_info->inline_version > 0 &&
3766             extra_info->inline_version >= ci->i_inline_version) {
3767                 ci->i_inline_version = extra_info->inline_version;
3768                 if (ci->i_inline_version != CEPH_INLINE_NONE &&
3769                     (newcaps & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)))
3770                         fill_inline = true;
3771         }
3772 
3773         if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
3774                 if (ci->i_auth_cap == cap) {
3775                         if (newcaps & ~extra_info->issued)
3776                                 wake = true;
3777 
3778                         if (ci->i_requested_max_size > max_size ||
3779                             !(le32_to_cpu(grant->wanted) & CEPH_CAP_ANY_FILE_WR)) {
3780                                 /* re-request max_size if necessary */
3781                                 ci->i_requested_max_size = 0;
3782                                 wake = true;
3783                         }
3784 
3785                         ceph_kick_flushing_inode_caps(session, ci);
3786                 }
3787                 up_read(&session->s_mdsc->snap_rwsem);
3788         }
3789         spin_unlock(&ci->i_ceph_lock);
3790 
3791         if (fill_inline)
3792                 ceph_fill_inline_data(inode, NULL, extra_info->inline_data,
3793                                       extra_info->inline_len);
3794 
3795         if (queue_trunc)
3796                 ceph_queue_vmtruncate(inode);
3797 
3798         if (writeback)
3799                 /*
3800                  * queue inode for writeback: we can't actually call
3801                  * filemap_write_and_wait, etc. from message handler
3802                  * context.
3803                  */
3804                 ceph_queue_writeback(inode);
3805         if (queue_invalidate)
3806                 ceph_queue_invalidate(inode);
3807         if (deleted_inode)
3808                 invalidate_aliases(inode);
3809         if (wake)
3810                 wake_up_all(&ci->i_cap_wq);
3811 
3812         mutex_unlock(&session->s_mutex);
3813         if (check_caps == 1)
3814                 ceph_check_caps(ci, flags | CHECK_CAPS_AUTHONLY | CHECK_CAPS_NOINVAL);
3815         else if (check_caps == 2)
3816                 ceph_check_caps(ci, flags | CHECK_CAPS_NOINVAL);
3817 }
3818 
3819 /*
3820  * Handle FLUSH_ACK from MDS, indicating that metadata we sent to the
3821  * MDS has been safely committed.
3822  */
3823 static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
3824                                  struct ceph_mds_caps *m,
3825                                  struct ceph_mds_session *session,
3826                                  struct ceph_cap *cap)
3827         __releases(ci->i_ceph_lock)
3828 {
3829         struct ceph_inode_info *ci = ceph_inode(inode);
3830         struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(inode->i_sb)->mdsc;
3831         struct ceph_client *cl = mdsc->fsc->client;
3832         struct ceph_cap_flush *cf, *tmp_cf;
3833         LIST_HEAD(to_remove);
3834         unsigned seq = le32_to_cpu(m->seq);
3835         int dirty = le32_to_cpu(m->dirty);
3836         int cleaned = 0;
3837         bool drop = false;
3838         bool wake_ci = false;
3839         bool wake_mdsc = false;
3840 
3841         list_for_each_entry_safe(cf, tmp_cf, &ci->i_cap_flush_list, i_list) {
3842                 /* Is this the one that was flushed? */
3843                 if (cf->tid == flush_tid)
3844                         cleaned = cf->caps;
3845 
3846                 /* Is this a capsnap? */
3847                 if (cf->is_capsnap)
3848                         continue;
3849 
3850                 if (cf->tid <= flush_tid) {
3851                         /*
3852                          * An earlier or current tid. The FLUSH_ACK should
3853                          * represent a superset of this flush's caps.
3854                          */
3855                         wake_ci |= __detach_cap_flush_from_ci(ci, cf);
3856                         list_add_tail(&cf->i_list, &to_remove);
3857                 } else {
3858                         /*
3859                          * This is a later one. Any caps in it are still dirty
3860                          * so don't count them as cleaned.
3861                          */
3862                         cleaned &= ~cf->caps;
3863                         if (!cleaned)
3864                                 break;
3865                 }
3866         }
3867 
3868         doutc(cl, "%p %llx.%llx mds%d seq %d on %s cleaned %s, flushing %s -> %s\n",
3869               inode, ceph_vinop(inode), session->s_mds, seq,
3870               ceph_cap_string(dirty), ceph_cap_string(cleaned),
3871               ceph_cap_string(ci->i_flushing_caps),
3872               ceph_cap_string(ci->i_flushing_caps & ~cleaned));
3873 
3874         if (list_empty(&to_remove) && !cleaned)
3875                 goto out;
3876 
3877         ci->i_flushing_caps &= ~cleaned;
3878 
3879         spin_lock(&mdsc->cap_dirty_lock);
3880 
3881         list_for_each_entry(cf, &to_remove, i_list)
3882                 wake_mdsc |= __detach_cap_flush_from_mdsc(mdsc, cf);
3883 
3884         if (ci->i_flushing_caps == 0) {
3885                 if (list_empty(&ci->i_cap_flush_list)) {
3886                         list_del_init(&ci->i_flushing_item);
3887                         if (!list_empty(&session->s_cap_flushing)) {
3888                                 struct inode *inode =
3889                                             &list_first_entry(&session->s_cap_flushing,
3890                                                               struct ceph_inode_info,
3891                                                               i_flushing_item)->netfs.inode;
3892                                 doutc(cl, " mds%d still flushing cap on %p %llx.%llx\n",
3893                                       session->s_mds, inode, ceph_vinop(inode));
3894                         }
3895                 }
3896                 mdsc->num_cap_flushing--;
3897                 doutc(cl, " %p %llx.%llx now !flushing\n", inode,
3898                       ceph_vinop(inode));
3899 
3900                 if (ci->i_dirty_caps == 0) {
3901                         doutc(cl, " %p %llx.%llx now clean\n", inode,
3902                               ceph_vinop(inode));
3903                         BUG_ON(!list_empty(&ci->i_dirty_item));
3904                         drop = true;
3905                         if (ci->i_wr_ref == 0 &&
3906                             ci->i_wrbuffer_ref_head == 0) {
3907                                 BUG_ON(!ci->i_head_snapc);
3908                                 ceph_put_snap_context(ci->i_head_snapc);
3909                                 ci->i_head_snapc = NULL;
3910                         }
3911                 } else {
3912                         BUG_ON(list_empty(&ci->i_dirty_item));
3913                 }
3914         }
3915         spin_unlock(&mdsc->cap_dirty_lock);
3916 
3917 out:
3918         spin_unlock(&ci->i_ceph_lock);
3919 
3920         while (!list_empty(&to_remove)) {
3921                 cf = list_first_entry(&to_remove,
3922                                       struct ceph_cap_flush, i_list);
3923                 list_del_init(&cf->i_list);
3924                 if (!cf->is_capsnap)
3925                         ceph_free_cap_flush(cf);
3926         }
3927 
3928         if (wake_ci)
3929                 wake_up_all(&ci->i_cap_wq);
3930         if (wake_mdsc)
3931                 wake_up_all(&mdsc->cap_flushing_wq);
3932         if (drop)
3933                 iput(inode);
3934 }
3935 
3936 void __ceph_remove_capsnap(struct inode *inode, struct ceph_cap_snap *capsnap,
3937                            bool *wake_ci, bool *wake_mdsc)
3938 {
3939         struct ceph_inode_info *ci = ceph_inode(inode);
3940         struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(inode->i_sb)->mdsc;
3941         struct ceph_client *cl = mdsc->fsc->client;
3942         bool ret;
3943 
3944         lockdep_assert_held(&ci->i_ceph_lock);
3945 
3946         doutc(cl, "removing capsnap %p, %p %llx.%llx ci %p\n", capsnap,
3947               inode, ceph_vinop(inode), ci);
3948 
3949         list_del_init(&capsnap->ci_item);
3950         ret = __detach_cap_flush_from_ci(ci, &capsnap->cap_flush);
3951         if (wake_ci)
3952                 *wake_ci = ret;
3953 
3954         spin_lock(&mdsc->cap_dirty_lock);
3955         if (list_empty(&ci->i_cap_flush_list))
3956                 list_del_init(&ci->i_flushing_item);
3957 
3958         ret = __detach_cap_flush_from_mdsc(mdsc, &capsnap->cap_flush);
3959         if (wake_mdsc)
3960                 *wake_mdsc = ret;
3961         spin_unlock(&mdsc->cap_dirty_lock);
3962 }
3963 
3964 void ceph_remove_capsnap(struct inode *inode, struct ceph_cap_snap *capsnap,
3965                          bool *wake_ci, bool *wake_mdsc)
3966 {
3967         struct ceph_inode_info *ci = ceph_inode(inode);
3968 
3969         lockdep_assert_held(&ci->i_ceph_lock);
3970 
3971         WARN_ON_ONCE(capsnap->dirty_pages || capsnap->writing);
3972         __ceph_remove_capsnap(inode, capsnap, wake_ci, wake_mdsc);
3973 }
3974 
3975 /*
3976  * Handle FLUSHSNAP_ACK.  MDS has flushed snap data to disk and we can
3977  * throw away our cap_snap.
3978  *
3979  * Caller hold s_mutex.
3980  */
3981 static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
3982                                      struct ceph_mds_caps *m,
3983                                      struct ceph_mds_session *session)
3984 {
3985         struct ceph_inode_info *ci = ceph_inode(inode);
3986         struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(inode->i_sb)->mdsc;
3987         struct ceph_client *cl = mdsc->fsc->client;
3988         u64 follows = le64_to_cpu(m->snap_follows);
3989         struct ceph_cap_snap *capsnap = NULL, *iter;
3990         bool wake_ci = false;
3991         bool wake_mdsc = false;
3992 
3993         doutc(cl, "%p %llx.%llx ci %p mds%d follows %lld\n", inode,
3994               ceph_vinop(inode), ci, session->s_mds, follows);
3995 
3996         spin_lock(&ci->i_ceph_lock);
3997         list_for_each_entry(iter, &ci->i_cap_snaps, ci_item) {
3998                 if (iter->follows == follows) {
3999                         if (iter->cap_flush.tid != flush_tid) {
4000                                 doutc(cl, " cap_snap %p follows %lld "
4001                                       "tid %lld != %lld\n", iter,
4002                                       follows, flush_tid,
4003                                       iter->cap_flush.tid);
4004                                 break;
4005                         }
4006                         capsnap = iter;
4007                         break;
4008                 } else {
4009                         doutc(cl, " skipping cap_snap %p follows %lld\n",
4010                               iter, iter->follows);
4011                 }
4012         }
4013         if (capsnap)
4014                 ceph_remove_capsnap(inode, capsnap, &wake_ci, &wake_mdsc);
4015         spin_unlock(&ci->i_ceph_lock);
4016 
4017         if (capsnap) {
4018                 ceph_put_snap_context(capsnap->context);
4019                 ceph_put_cap_snap(capsnap);
4020                 if (wake_ci)
4021                         wake_up_all(&ci->i_cap_wq);
4022                 if (wake_mdsc)
4023                         wake_up_all(&mdsc->cap_flushing_wq);
4024                 iput(inode);
4025         }
4026 }
4027 
4028 /*
4029  * Handle TRUNC from MDS, indicating file truncation.
4030  *
4031  * caller hold s_mutex.
4032  */
4033 static bool handle_cap_trunc(struct inode *inode,
4034                              struct ceph_mds_caps *trunc,
4035                              struct ceph_mds_session *session,
4036                              struct cap_extra_info *extra_info)
4037 {
4038         struct ceph_inode_info *ci = ceph_inode(inode);
4039         struct ceph_client *cl = ceph_inode_to_client(inode);
4040         int mds = session->s_mds;
4041         int seq = le32_to_cpu(trunc->seq);
4042         u32 truncate_seq = le32_to_cpu(trunc->truncate_seq);
4043         u64 truncate_size = le64_to_cpu(trunc->truncate_size);
4044         u64 size = le64_to_cpu(trunc->size);
4045         int implemented = 0;
4046         int dirty = __ceph_caps_dirty(ci);
4047         int issued = __ceph_caps_issued(ceph_inode(inode), &implemented);
4048         bool queue_trunc = false;
4049 
4050         lockdep_assert_held(&ci->i_ceph_lock);
4051 
4052         issued |= implemented | dirty;
4053 
4054         /*
4055          * If there is at least one crypto block then we'll trust
4056          * fscrypt_file_size. If the real length of the file is 0, then
4057          * ignore it (it has probably been truncated down to 0 by the MDS).
4058          */
4059         if (IS_ENCRYPTED(inode) && size)
4060                 size = extra_info->fscrypt_file_size;
4061 
4062         doutc(cl, "%p %llx.%llx mds%d seq %d to %lld truncate seq %d\n",
4063               inode, ceph_vinop(inode), mds, seq, truncate_size, truncate_seq);
4064         queue_trunc = ceph_fill_file_size(inode, issued,
4065                                           truncate_seq, truncate_size, size);
4066         return queue_trunc;
4067 }
4068 
4069 /*
4070  * Handle EXPORT from MDS.  Cap is being migrated _from_ this mds to a
4071  * different one.  If we are the most recent migration we've seen (as
4072  * indicated by mseq), make note of the migrating cap bits for the
4073  * duration (until we see the corresponding IMPORT).
4074  *
4075  * caller holds s_mutex
4076  */
4077 static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
4078                               struct ceph_mds_cap_peer *ph,
4079                               struct ceph_mds_session *session)
4080 {
4081         struct ceph_mds_client *mdsc = ceph_inode_to_fs_client(inode)->mdsc;
4082         struct ceph_client *cl = mdsc->fsc->client;
4083         struct ceph_mds_session *tsession = NULL;
4084         struct ceph_cap *cap, *tcap, *new_cap = NULL;
4085         struct ceph_inode_info *ci = ceph_inode(inode);
4086         u64 t_cap_id;
4087         unsigned mseq = le32_to_cpu(ex->migrate_seq);
4088         unsigned t_seq, t_mseq;
4089         int target, issued;
4090         int mds = session->s_mds;
4091 
4092         if (ph) {
4093                 t_cap_id = le64_to_cpu(ph->cap_id);
4094                 t_seq = le32_to_cpu(ph->seq);
4095                 t_mseq = le32_to_cpu(ph->mseq);
4096                 target = le32_to_cpu(ph->mds);
4097         } else {
4098                 t_cap_id = t_seq = t_mseq = 0;
4099                 target = -1;
4100         }
4101 
4102         doutc(cl, "%p %llx.%llx ci %p mds%d mseq %d target %d\n",
4103               inode, ceph_vinop(inode), ci, mds, mseq, target);
4104 retry:
4105         down_read(&mdsc->snap_rwsem);
4106         spin_lock(&ci->i_ceph_lock);
4107         cap = __get_cap_for_mds(ci, mds);
4108         if (!cap || cap->cap_id != le64_to_cpu(ex->cap_id))
4109                 goto out_unlock;
4110 
4111         if (target < 0) {
4112                 ceph_remove_cap(mdsc, cap, false);
4113                 goto out_unlock;
4114         }
4115 
4116         /*
4117          * now we know we haven't received the cap import message yet
4118          * because the exported cap still exist.
4119          */
4120 
4121         issued = cap->issued;
4122         if (issued != cap->implemented)
4123                 pr_err_ratelimited_client(cl, "issued != implemented: "
4124                                           "%p %llx.%llx mds%d seq %d mseq %d"
4125                                           " issued %s implemented %s\n",
4126                                           inode, ceph_vinop(inode), mds,
4127                                           cap->seq, cap->mseq,
4128                                           ceph_cap_string(issued),
4129                                           ceph_cap_string(cap->implemented));
4130 
4131 
4132         tcap = __get_cap_for_mds(ci, target);
4133         if (tcap) {
4134                 /* already have caps from the target */
4135                 if (tcap->cap_id == t_cap_id &&
4136                     ceph_seq_cmp(tcap->seq, t_seq) < 0) {
4137                         doutc(cl, " updating import cap %p mds%d\n", tcap,
4138                               target);
4139                         tcap->cap_id = t_cap_id;
4140                         tcap->seq = t_seq - 1;
4141                         tcap->issue_seq = t_seq - 1;
4142                         tcap->issued |= issued;
4143                         tcap->implemented |= issued;
4144                         if (cap == ci->i_auth_cap) {
4145                                 ci->i_auth_cap = tcap;
4146                                 change_auth_cap_ses(ci, tcap->session);
4147                         }
4148                 }
4149                 ceph_remove_cap(mdsc, cap, false);
4150                 goto out_unlock;
4151         } else if (tsession) {
4152                 /* add placeholder for the export tagert */
4153                 int flag = (cap == ci->i_auth_cap) ? CEPH_CAP_FLAG_AUTH : 0;
4154                 tcap = new_cap;
4155                 ceph_add_cap(inode, tsession, t_cap_id, issued, 0,
4156                              t_seq - 1, t_mseq, (u64)-1, flag, &new_cap);
4157 
4158                 if (!list_empty(&ci->i_cap_flush_list) &&
4159                     ci->i_auth_cap == tcap) {
4160                         spin_lock(&mdsc->cap_dirty_lock);
4161                         list_move_tail(&ci->i_flushing_item,
4162                                        &tcap->session->s_cap_flushing);
4163                         spin_unlock(&mdsc->cap_dirty_lock);
4164                 }
4165 
4166                 ceph_remove_cap(mdsc, cap, false);
4167                 goto out_unlock;
4168         }
4169 
4170         spin_unlock(&ci->i_ceph_lock);
4171         up_read(&mdsc->snap_rwsem);
4172         mutex_unlock(&session->s_mutex);
4173 
4174         /* open target session */
4175         tsession = ceph_mdsc_open_export_target_session(mdsc, target);
4176         if (!IS_ERR(tsession)) {
4177                 if (mds > target) {
4178                         mutex_lock(&session->s_mutex);
4179                         mutex_lock_nested(&tsession->s_mutex,
4180                                           SINGLE_DEPTH_NESTING);
4181                 } else {
4182                         mutex_lock(&tsession->s_mutex);
4183                         mutex_lock_nested(&session->s_mutex,
4184                                           SINGLE_DEPTH_NESTING);
4185                 }
4186                 new_cap = ceph_get_cap(mdsc, NULL);
4187         } else {
4188                 WARN_ON(1);
4189                 tsession = NULL;
4190                 target = -1;
4191                 mutex_lock(&session->s_mutex);
4192         }
4193         goto retry;
4194 
4195 out_unlock:
4196         spin_unlock(&ci->i_ceph_lock);
4197         up_read(&mdsc->snap_rwsem);
4198         mutex_unlock(&session->s_mutex);
4199         if (tsession) {
4200                 mutex_unlock(&tsession->s_mutex);
4201                 ceph_put_mds_session(tsession);
4202         }
4203         if (new_cap)
4204                 ceph_put_cap(mdsc, new_cap);
4205 }
4206 
4207 /*
4208  * Handle cap IMPORT.
4209  *
4210  * caller holds s_mutex. acquires i_ceph_lock
4211  */
4212 static void handle_cap_import(struct ceph_mds_client *mdsc,
4213                               struct inode *inode, struct ceph_mds_caps *im,
4214                               struct ceph_mds_cap_peer *ph,
4215                               struct ceph_mds_session *session,
4216                               struct ceph_cap **target_cap, int *old_issued)
4217 {
4218         struct ceph_inode_info *ci = ceph_inode(inode);
4219         struct ceph_client *cl = mdsc->fsc->client;
4220         struct ceph_cap *cap, *ocap, *new_cap = NULL;
4221         int mds = session->s_mds;
4222         int issued;
4223         unsigned caps = le32_to_cpu(im->caps);
4224         unsigned wanted = le32_to_cpu(im->wanted);
4225         unsigned seq = le32_to_cpu(im->seq);
4226         unsigned mseq = le32_to_cpu(im->migrate_seq);
4227         u64 realmino = le64_to_cpu(im->realm);
4228         u64 cap_id = le64_to_cpu(im->cap_id);
4229         u64 p_cap_id;
4230         int peer;
4231 
4232         if (ph) {
4233                 p_cap_id = le64_to_cpu(ph->cap_id);
4234                 peer = le32_to_cpu(ph->mds);
4235         } else {
4236                 p_cap_id = 0;
4237                 peer = -1;
4238         }
4239 
4240         doutc(cl, "%p %llx.%llx ci %p mds%d mseq %d peer %d\n",
4241               inode, ceph_vinop(inode), ci, mds, mseq, peer);
4242 retry:
4243         cap = __get_cap_for_mds(ci, mds);
4244         if (!cap) {
4245                 if (!new_cap) {
4246                         spin_unlock(&ci->i_ceph_lock);
4247                         new_cap = ceph_get_cap(mdsc, NULL);
4248                         spin_lock(&ci->i_ceph_lock);
4249                         goto retry;
4250                 }
4251                 cap = new_cap;
4252         } else {
4253                 if (new_cap) {
4254                         ceph_put_cap(mdsc, new_cap);
4255                         new_cap = NULL;
4256                 }
4257         }
4258 
4259         __ceph_caps_issued(ci, &issued);
4260         issued |= __ceph_caps_dirty(ci);
4261 
4262         ceph_add_cap(inode, session, cap_id, caps, wanted, seq, mseq,
4263                      realmino, CEPH_CAP_FLAG_AUTH, &new_cap);
4264 
4265         ocap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL;
4266         if (ocap && ocap->cap_id == p_cap_id) {
4267                 doutc(cl, " remove export cap %p mds%d flags %d\n",
4268                       ocap, peer, ph->flags);
4269                 if ((ph->flags & CEPH_CAP_FLAG_AUTH) &&
4270                     (ocap->seq != le32_to_cpu(ph->seq) ||
4271                      ocap->mseq != le32_to_cpu(ph->mseq))) {
4272                         pr_err_ratelimited_client(cl, "mismatched seq/mseq: "
4273                                         "%p %llx.%llx mds%d seq %d mseq %d"
4274                                         " importer mds%d has peer seq %d mseq %d\n",
4275                                         inode, ceph_vinop(inode), peer,
4276                                         ocap->seq, ocap->mseq, mds,
4277                                         le32_to_cpu(ph->seq),
4278                                         le32_to_cpu(ph->mseq));
4279                 }
4280                 ceph_remove_cap(mdsc, ocap, (ph->flags & CEPH_CAP_FLAG_RELEASE));
4281         }
4282 
4283         *old_issued = issued;
4284         *target_cap = cap;
4285 }
4286 
4287 #ifdef CONFIG_FS_ENCRYPTION
4288 static int parse_fscrypt_fields(void **p, void *end,
4289                                 struct cap_extra_info *extra)
4290 {
4291         u32 len;
4292 
4293         ceph_decode_32_safe(p, end, extra->fscrypt_auth_len, bad);
4294         if (extra->fscrypt_auth_len) {
4295                 ceph_decode_need(p, end, extra->fscrypt_auth_len, bad);
4296                 extra->fscrypt_auth = kmalloc(extra->fscrypt_auth_len,
4297                                               GFP_KERNEL);
4298                 if (!extra->fscrypt_auth)
4299                         return -ENOMEM;
4300                 ceph_decode_copy_safe(p, end, extra->fscrypt_auth,
4301                                         extra->fscrypt_auth_len, bad);
4302         }
4303 
4304         ceph_decode_32_safe(p, end, len, bad);
4305         if (len >= sizeof(u64)) {
4306                 ceph_decode_64_safe(p, end, extra->fscrypt_file_size, bad);
4307                 len -= sizeof(u64);
4308         }
4309         ceph_decode_skip_n(p, end, len, bad);
4310         return 0;
4311 bad:
4312         return -EIO;
4313 }
4314 #else
4315 static int parse_fscrypt_fields(void **p, void *end,
4316                                 struct cap_extra_info *extra)
4317 {
4318         u32 len;
4319 
4320         /* Don't care about these fields unless we're encryption-capable */
4321         ceph_decode_32_safe(p, end, len, bad);
4322         if (len)
4323                 ceph_decode_skip_n(p, end, len, bad);
4324         ceph_decode_32_safe(p, end, len, bad);
4325         if (len)
4326                 ceph_decode_skip_n(p, end, len, bad);
4327         return 0;
4328 bad:
4329         return -EIO;
4330 }
4331 #endif
4332 
4333 /*
4334  * Handle a caps message from the MDS.
4335  *
4336  * Identify the appropriate session, inode, and call the right handler
4337  * based on the cap op.
4338  */
4339 void ceph_handle_caps(struct ceph_mds_session *session,
4340                       struct ceph_msg *msg)
4341 {
4342         struct ceph_mds_client *mdsc = session->s_mdsc;
4343         struct ceph_client *cl = mdsc->fsc->client;
4344         struct inode *inode;
4345         struct ceph_inode_info *ci;
4346         struct ceph_cap *cap;
4347         struct ceph_mds_caps *h;
4348         struct ceph_mds_cap_peer *peer = NULL;
4349         struct ceph_snap_realm *realm = NULL;
4350         int op;
4351         int msg_version = le16_to_cpu(msg->hdr.version);
4352         u32 seq, mseq;
4353         struct ceph_vino vino;
4354         void *snaptrace;
4355         size_t snaptrace_len;
4356         void *p, *end;
4357         struct cap_extra_info extra_info = {};
4358         bool queue_trunc;
4359         bool close_sessions = false;
4360         bool do_cap_release = false;
4361 
4362         doutc(cl, "from mds%d\n", session->s_mds);
4363 
4364         if (!ceph_inc_mds_stopping_blocker(mdsc, session))
4365                 return;
4366 
4367         /* decode */
4368         end = msg->front.iov_base + msg->front.iov_len;
4369         if (msg->front.iov_len < sizeof(*h))
4370                 goto bad;
4371         h = msg->front.iov_base;
4372         op = le32_to_cpu(h->op);
4373         vino.ino = le64_to_cpu(h->ino);
4374         vino.snap = CEPH_NOSNAP;
4375         seq = le32_to_cpu(h->seq);
4376         mseq = le32_to_cpu(h->migrate_seq);
4377 
4378         snaptrace = h + 1;
4379         snaptrace_len = le32_to_cpu(h->snap_trace_len);
4380         p = snaptrace + snaptrace_len;
4381 
4382         if (msg_version >= 2) {
4383                 u32 flock_len;
4384                 ceph_decode_32_safe(&p, end, flock_len, bad);
4385                 if (p + flock_len > end)
4386                         goto bad;
4387                 p += flock_len;
4388         }
4389 
4390         if (msg_version >= 3) {
4391                 if (op == CEPH_CAP_OP_IMPORT) {
4392                         if (p + sizeof(*peer) > end)
4393                                 goto bad;
4394                         peer = p;
4395                         p += sizeof(*peer);
4396                 } else if (op == CEPH_CAP_OP_EXPORT) {
4397                         /* recorded in unused fields */
4398                         peer = (void *)&h->size;
4399                 }
4400         }
4401 
4402         if (msg_version >= 4) {
4403                 ceph_decode_64_safe(&p, end, extra_info.inline_version, bad);
4404                 ceph_decode_32_safe(&p, end, extra_info.inline_len, bad);
4405                 if (p + extra_info.inline_len > end)
4406                         goto bad;
4407                 extra_info.inline_data = p;
4408                 p += extra_info.inline_len;
4409         }
4410 
4411         if (msg_version >= 5) {
4412                 struct ceph_osd_client  *osdc = &mdsc->fsc->client->osdc;
4413                 u32                     epoch_barrier;
4414 
4415                 ceph_decode_32_safe(&p, end, epoch_barrier, bad);
4416                 ceph_osdc_update_epoch_barrier(osdc, epoch_barrier);
4417         }
4418 
4419         if (msg_version >= 8) {
4420                 u32 pool_ns_len;
4421 
4422                 /* version >= 6 */
4423                 ceph_decode_skip_64(&p, end, bad);      // flush_tid
4424                 /* version >= 7 */
4425                 ceph_decode_skip_32(&p, end, bad);      // caller_uid
4426                 ceph_decode_skip_32(&p, end, bad);      // caller_gid
4427                 /* version >= 8 */
4428                 ceph_decode_32_safe(&p, end, pool_ns_len, bad);
4429                 if (pool_ns_len > 0) {
4430                         ceph_decode_need(&p, end, pool_ns_len, bad);
4431                         extra_info.pool_ns =
4432                                 ceph_find_or_create_string(p, pool_ns_len);
4433                         p += pool_ns_len;
4434                 }
4435         }
4436 
4437         if (msg_version >= 9) {
4438                 struct ceph_timespec *btime;
4439 
4440                 if (p + sizeof(*btime) > end)
4441                         goto bad;
4442                 btime = p;
4443                 ceph_decode_timespec64(&extra_info.btime, btime);
4444                 p += sizeof(*btime);
4445                 ceph_decode_64_safe(&p, end, extra_info.change_attr, bad);
4446         }
4447 
4448         if (msg_version >= 11) {
4449                 /* version >= 10 */
4450                 ceph_decode_skip_32(&p, end, bad); // flags
4451                 /* version >= 11 */
4452                 extra_info.dirstat_valid = true;
4453                 ceph_decode_64_safe(&p, end, extra_info.nfiles, bad);
4454                 ceph_decode_64_safe(&p, end, extra_info.nsubdirs, bad);
4455         }
4456 
4457         if (msg_version >= 12) {
4458                 if (parse_fscrypt_fields(&p, end, &extra_info))
4459                         goto bad;
4460         }
4461 
4462         /* lookup ino */
4463         inode = ceph_find_inode(mdsc->fsc->sb, vino);
4464         doutc(cl, " op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op),
4465               vino.ino, vino.snap, inode);
4466 
4467         mutex_lock(&session->s_mutex);
4468         doutc(cl, " mds%d seq %lld cap seq %u\n", session->s_mds,
4469               session->s_seq, (unsigned)seq);
4470 
4471         if (!inode) {
4472                 doutc(cl, " i don't have ino %llx\n", vino.ino);
4473 
4474                 switch (op) {
4475                 case CEPH_CAP_OP_IMPORT:
4476                 case CEPH_CAP_OP_REVOKE:
4477                 case CEPH_CAP_OP_GRANT:
4478                         do_cap_release = true;
4479                         break;
4480                 default:
4481                         break;
4482                 }
4483                 goto flush_cap_releases;
4484         }
4485         ci = ceph_inode(inode);
4486 
4487         /* these will work even if we don't have a cap yet */
4488         switch (op) {
4489         case CEPH_CAP_OP_FLUSHSNAP_ACK:
4490                 handle_cap_flushsnap_ack(inode, le64_to_cpu(msg->hdr.tid),
4491                                          h, session);
4492                 goto done;
4493 
4494         case CEPH_CAP_OP_EXPORT:
4495                 handle_cap_export(inode, h, peer, session);
4496                 goto done_unlocked;
4497 
4498         case CEPH_CAP_OP_IMPORT:
4499                 realm = NULL;
4500                 if (snaptrace_len) {
4501                         down_write(&mdsc->snap_rwsem);
4502                         if (ceph_update_snap_trace(mdsc, snaptrace,
4503                                                    snaptrace + snaptrace_len,
4504                                                    false, &realm)) {
4505                                 up_write(&mdsc->snap_rwsem);
4506                                 close_sessions = true;
4507                                 goto done;
4508                         }
4509                         downgrade_write(&mdsc->snap_rwsem);
4510                 } else {
4511                         down_read(&mdsc->snap_rwsem);
4512                 }
4513                 spin_lock(&ci->i_ceph_lock);
4514                 handle_cap_import(mdsc, inode, h, peer, session,
4515                                   &cap, &extra_info.issued);
4516                 handle_cap_grant(inode, session, cap,
4517                                  h, msg->middle, &extra_info);
4518                 if (realm)
4519                         ceph_put_snap_realm(mdsc, realm);
4520                 goto done_unlocked;
4521         }
4522 
4523         /* the rest require a cap */
4524         spin_lock(&ci->i_ceph_lock);
4525         cap = __get_cap_for_mds(ceph_inode(inode), session->s_mds);
4526         if (!cap) {
4527                 doutc(cl, " no cap on %p ino %llx.%llx from mds%d\n",
4528                       inode, ceph_ino(inode), ceph_snap(inode),
4529                       session->s_mds);
4530                 spin_unlock(&ci->i_ceph_lock);
4531                 switch (op) {
4532                 case CEPH_CAP_OP_REVOKE:
4533                 case CEPH_CAP_OP_GRANT:
4534                         do_cap_release = true;
4535                         break;
4536                 default:
4537                         break;
4538                 }
4539                 goto flush_cap_releases;
4540         }
4541 
4542         /* note that each of these drops i_ceph_lock for us */
4543         switch (op) {
4544         case CEPH_CAP_OP_REVOKE:
4545         case CEPH_CAP_OP_GRANT:
4546                 __ceph_caps_issued(ci, &extra_info.issued);
4547                 extra_info.issued |= __ceph_caps_dirty(ci);
4548                 handle_cap_grant(inode, session, cap,
4549                                  h, msg->middle, &extra_info);
4550                 goto done_unlocked;
4551 
4552         case CEPH_CAP_OP_FLUSH_ACK:
4553                 handle_cap_flush_ack(inode, le64_to_cpu(msg->hdr.tid),
4554                                      h, session, cap);
4555                 break;
4556 
4557         case CEPH_CAP_OP_TRUNC:
4558                 queue_trunc = handle_cap_trunc(inode, h, session,
4559                                                 &extra_info);
4560                 spin_unlock(&ci->i_ceph_lock);
4561                 if (queue_trunc)
4562                         ceph_queue_vmtruncate(inode);
4563                 break;
4564 
4565         default:
4566                 spin_unlock(&ci->i_ceph_lock);
4567                 pr_err_client(cl, "unknown cap op %d %s\n", op,
4568                               ceph_cap_op_name(op));
4569         }
4570 
4571 done:
4572         mutex_unlock(&session->s_mutex);
4573 done_unlocked:
4574         iput(inode);
4575 out:
4576         ceph_dec_mds_stopping_blocker(mdsc);
4577 
4578         ceph_put_string(extra_info.pool_ns);
4579 
4580         /* Defer closing the sessions after s_mutex lock being released */
4581         if (close_sessions)
4582                 ceph_mdsc_close_sessions(mdsc);
4583 
4584         kfree(extra_info.fscrypt_auth);
4585         return;
4586 
4587 flush_cap_releases:
4588         /*
4589          * send any cap release message to try to move things
4590          * along for the mds (who clearly thinks we still have this
4591          * cap).
4592          */
4593         if (do_cap_release) {
4594                 cap = ceph_get_cap(mdsc, NULL);
4595                 cap->cap_ino = vino.ino;
4596                 cap->queue_release = 1;
4597                 cap->cap_id = le64_to_cpu(h->cap_id);
4598                 cap->mseq = mseq;
4599                 cap->seq = seq;
4600                 cap->issue_seq = seq;
4601                 spin_lock(&session->s_cap_lock);
4602                 __ceph_queue_cap_release(session, cap);
4603                 spin_unlock(&session->s_cap_lock);
4604         }
4605         ceph_flush_cap_releases(mdsc, session);
4606         goto done;
4607 
4608 bad:
4609         pr_err_client(cl, "corrupt message\n");
4610         ceph_msg_dump(msg);
4611         goto out;
4612 }
4613 
4614 /*
4615  * Delayed work handler to process end of delayed cap release LRU list.
4616  *
4617  * If new caps are added to the list while processing it, these won't get
4618  * processed in this run.  In this case, the ci->i_hold_caps_max will be
4619  * returned so that the work can be scheduled accordingly.
4620  */
4621 unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc)
4622 {
4623         struct ceph_client *cl = mdsc->fsc->client;
4624         struct inode *inode;
4625         struct ceph_inode_info *ci;
4626         struct ceph_mount_options *opt = mdsc->fsc->mount_options;
4627         unsigned long delay_max = opt->caps_wanted_delay_max * HZ;
4628         unsigned long loop_start = jiffies;
4629         unsigned long delay = 0;
4630 
4631         doutc(cl, "begin\n");
4632         spin_lock(&mdsc->cap_delay_lock);
4633         while (!list_empty(&mdsc->cap_delay_list)) {
4634                 ci = list_first_entry(&mdsc->cap_delay_list,
4635                                       struct ceph_inode_info,
4636                                       i_cap_delay_list);
4637                 if (time_before(loop_start, ci->i_hold_caps_max - delay_max)) {
4638                         doutc(cl, "caps added recently.  Exiting loop");
4639                         delay = ci->i_hold_caps_max;
4640                         break;
4641                 }
4642                 if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 &&
4643                     time_before(jiffies, ci->i_hold_caps_max))
4644                         break;
4645                 list_del_init(&ci->i_cap_delay_list);
4646 
4647                 inode = igrab(&ci->netfs.inode);
4648                 if (inode) {
4649                         spin_unlock(&mdsc->cap_delay_lock);
4650                         doutc(cl, "on %p %llx.%llx\n", inode,
4651                               ceph_vinop(inode));
4652                         ceph_check_caps(ci, 0);
4653                         iput(inode);
4654                         spin_lock(&mdsc->cap_delay_lock);
4655                 }
4656 
4657                 /*
4658                  * Make sure too many dirty caps or general
4659                  * slowness doesn't block mdsc delayed work,
4660                  * preventing send_renew_caps() from running.
4661                  */
4662                 if (jiffies - loop_start >= 5 * HZ)
4663                         break;
4664         }
4665         spin_unlock(&mdsc->cap_delay_lock);
4666         doutc(cl, "done\n");
4667 
4668         return delay;
4669 }
4670 
4671 /*
4672  * Flush all dirty caps to the mds
4673  */
4674 static void flush_dirty_session_caps(struct ceph_mds_session *s)
4675 {
4676         struct ceph_mds_client *mdsc = s->s_mdsc;
4677         struct ceph_client *cl = mdsc->fsc->client;
4678         struct ceph_inode_info *ci;
4679         struct inode *inode;
4680 
4681         doutc(cl, "begin\n");
4682         spin_lock(&mdsc->cap_dirty_lock);
4683         while (!list_empty(&s->s_cap_dirty)) {
4684                 ci = list_first_entry(&s->s_cap_dirty, struct ceph_inode_info,
4685                                       i_dirty_item);
4686                 inode = &ci->netfs.inode;
4687                 ihold(inode);
4688                 doutc(cl, "%p %llx.%llx\n", inode, ceph_vinop(inode));
4689                 spin_unlock(&mdsc->cap_dirty_lock);
4690                 ceph_wait_on_async_create(inode);
4691                 ceph_check_caps(ci, CHECK_CAPS_FLUSH);
4692                 iput(inode);
4693                 spin_lock(&mdsc->cap_dirty_lock);
4694         }
4695         spin_unlock(&mdsc->cap_dirty_lock);
4696         doutc(cl, "done\n");
4697 }
4698 
4699 void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
4700 {
4701         ceph_mdsc_iterate_sessions(mdsc, flush_dirty_session_caps, true);
4702 }
4703 
4704 void __ceph_touch_fmode(struct ceph_inode_info *ci,
4705                         struct ceph_mds_client *mdsc, int fmode)
4706 {
4707         unsigned long now = jiffies;
4708         if (fmode & CEPH_FILE_MODE_RD)
4709                 ci->i_last_rd = now;
4710         if (fmode & CEPH_FILE_MODE_WR)
4711                 ci->i_last_wr = now;
4712         /* queue periodic check */
4713         if (fmode &&
4714             __ceph_is_any_real_caps(ci) &&
4715             list_empty(&ci->i_cap_delay_list))
4716                 __cap_delay_requeue(mdsc, ci);
4717 }
4718 
4719 void ceph_get_fmode(struct ceph_inode_info *ci, int fmode, int count)
4720 {
4721         struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(ci->netfs.inode.i_sb);
4722         int bits = (fmode << 1) | 1;
4723         bool already_opened = false;
4724         int i;
4725 
4726         if (count == 1)
4727                 atomic64_inc(&mdsc->metric.opened_files);
4728 
4729         spin_lock(&ci->i_ceph_lock);
4730         for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
4731                 /*
4732                  * If any of the mode ref is larger than 0,
4733                  * that means it has been already opened by
4734                  * others. Just skip checking the PIN ref.
4735                  */
4736                 if (i && ci->i_nr_by_mode[i])
4737                         already_opened = true;
4738 
4739                 if (bits & (1 << i))
4740                         ci->i_nr_by_mode[i] += count;
4741         }
4742 
4743         if (!already_opened)
4744                 percpu_counter_inc(&mdsc->metric.opened_inodes);
4745         spin_unlock(&ci->i_ceph_lock);
4746 }
4747 
4748 /*
4749  * Drop open file reference.  If we were the last open file,
4750  * we may need to release capabilities to the MDS (or schedule
4751  * their delayed release).
4752  */
4753 void ceph_put_fmode(struct ceph_inode_info *ci, int fmode, int count)
4754 {
4755         struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(ci->netfs.inode.i_sb);
4756         int bits = (fmode << 1) | 1;
4757         bool is_closed = true;
4758         int i;
4759 
4760         if (count == 1)
4761                 atomic64_dec(&mdsc->metric.opened_files);
4762 
4763         spin_lock(&ci->i_ceph_lock);
4764         for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
4765                 if (bits & (1 << i)) {
4766                         BUG_ON(ci->i_nr_by_mode[i] < count);
4767                         ci->i_nr_by_mode[i] -= count;
4768                 }
4769 
4770                 /*
4771                  * If any of the mode ref is not 0 after
4772                  * decreased, that means it is still opened
4773                  * by others. Just skip checking the PIN ref.
4774                  */
4775                 if (i && ci->i_nr_by_mode[i])
4776                         is_closed = false;
4777         }
4778 
4779         if (is_closed)
4780                 percpu_counter_dec(&mdsc->metric.opened_inodes);
4781         spin_unlock(&ci->i_ceph_lock);
4782 }
4783 
4784 /*
4785  * For a soon-to-be unlinked file, drop the LINK caps. If it
4786  * looks like the link count will hit 0, drop any other caps (other
4787  * than PIN) we don't specifically want (due to the file still being
4788  * open).
4789  */
4790 int ceph_drop_caps_for_unlink(struct inode *inode)
4791 {
4792         struct ceph_inode_info *ci = ceph_inode(inode);
4793         int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
4794 
4795         spin_lock(&ci->i_ceph_lock);
4796         if (inode->i_nlink == 1) {
4797                 drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
4798 
4799                 if (__ceph_caps_dirty(ci)) {
4800                         struct ceph_mds_client *mdsc =
4801                                 ceph_inode_to_fs_client(inode)->mdsc;
4802 
4803                         doutc(mdsc->fsc->client, "%p %llx.%llx\n", inode,
4804                               ceph_vinop(inode));
4805                         spin_lock(&mdsc->cap_delay_lock);
4806                         ci->i_ceph_flags |= CEPH_I_FLUSH;
4807                         if (!list_empty(&ci->i_cap_delay_list))
4808                                 list_del_init(&ci->i_cap_delay_list);
4809                         list_add_tail(&ci->i_cap_delay_list,
4810                                       &mdsc->cap_unlink_delay_list);
4811                         spin_unlock(&mdsc->cap_delay_lock);
4812 
4813                         /*
4814                          * Fire the work immediately, because the MDS maybe
4815                          * waiting for caps release.
4816                          */
4817                         ceph_queue_cap_unlink_work(mdsc);
4818                 }
4819         }
4820         spin_unlock(&ci->i_ceph_lock);
4821         return drop;
4822 }
4823 
4824 /*
4825  * Helpers for embedding cap and dentry lease releases into mds
4826  * requests.
4827  *
4828  * @force is used by dentry_release (below) to force inclusion of a
4829  * record for the directory inode, even when there aren't any caps to
4830  * drop.
4831  */
4832 int ceph_encode_inode_release(void **p, struct inode *inode,
4833                               int mds, int drop, int unless, int force)
4834 {
4835         struct ceph_inode_info *ci = ceph_inode(inode);
4836         struct ceph_client *cl = ceph_inode_to_client(inode);
4837         struct ceph_cap *cap;
4838         struct ceph_mds_request_release *rel = *p;
4839         int used, dirty;
4840         int ret = 0;
4841 
4842         spin_lock(&ci->i_ceph_lock);
4843         used = __ceph_caps_used(ci);
4844         dirty = __ceph_caps_dirty(ci);
4845 
4846         doutc(cl, "%p %llx.%llx mds%d used|dirty %s drop %s unless %s\n",
4847               inode, ceph_vinop(inode), mds, ceph_cap_string(used|dirty),
4848               ceph_cap_string(drop), ceph_cap_string(unless));
4849 
4850         /* only drop unused, clean caps */
4851         drop &= ~(used | dirty);
4852 
4853         cap = __get_cap_for_mds(ci, mds);
4854         if (cap && __cap_is_valid(cap)) {
4855                 unless &= cap->issued;
4856                 if (unless) {
4857                         if (unless & CEPH_CAP_AUTH_EXCL)
4858                                 drop &= ~CEPH_CAP_AUTH_SHARED;
4859                         if (unless & CEPH_CAP_LINK_EXCL)
4860                                 drop &= ~CEPH_CAP_LINK_SHARED;
4861                         if (unless & CEPH_CAP_XATTR_EXCL)
4862                                 drop &= ~CEPH_CAP_XATTR_SHARED;
4863                         if (unless & CEPH_CAP_FILE_EXCL)
4864                                 drop &= ~CEPH_CAP_FILE_SHARED;
4865                 }
4866 
4867                 if (force || (cap->issued & drop)) {
4868                         if (cap->issued & drop) {
4869                                 int wanted = __ceph_caps_wanted(ci);
4870                                 doutc(cl, "%p %llx.%llx cap %p %s -> %s, "
4871                                       "wanted %s -> %s\n", inode,
4872                                       ceph_vinop(inode), cap,
4873                                       ceph_cap_string(cap->issued),
4874                                       ceph_cap_string(cap->issued & ~drop),
4875                                       ceph_cap_string(cap->mds_wanted),
4876                                       ceph_cap_string(wanted));
4877 
4878                                 cap->issued &= ~drop;
4879                                 cap->implemented &= ~drop;
4880                                 cap->mds_wanted = wanted;
4881                                 if (cap == ci->i_auth_cap &&
4882                                     !(wanted & CEPH_CAP_ANY_FILE_WR))
4883                                         ci->i_requested_max_size = 0;
4884                         } else {
4885                                 doutc(cl, "%p %llx.%llx cap %p %s (force)\n",
4886                                       inode, ceph_vinop(inode), cap,
4887                                       ceph_cap_string(cap->issued));
4888                         }
4889 
4890                         rel->ino = cpu_to_le64(ceph_ino(inode));
4891                         rel->cap_id = cpu_to_le64(cap->cap_id);
4892                         rel->seq = cpu_to_le32(cap->seq);
4893                         rel->issue_seq = cpu_to_le32(cap->issue_seq);
4894                         rel->mseq = cpu_to_le32(cap->mseq);
4895                         rel->caps = cpu_to_le32(cap->implemented);
4896                         rel->wanted = cpu_to_le32(cap->mds_wanted);
4897                         rel->dname_len = 0;
4898                         rel->dname_seq = 0;
4899                         *p += sizeof(*rel);
4900                         ret = 1;
4901                 } else {
4902                         doutc(cl, "%p %llx.%llx cap %p %s (noop)\n",
4903                               inode, ceph_vinop(inode), cap,
4904                               ceph_cap_string(cap->issued));
4905                 }
4906         }
4907         spin_unlock(&ci->i_ceph_lock);
4908         return ret;
4909 }
4910 
4911 /**
4912  * ceph_encode_dentry_release - encode a dentry release into an outgoing request
4913  * @p: outgoing request buffer
4914  * @dentry: dentry to release
4915  * @dir: dir to release it from
4916  * @mds: mds that we're speaking to
4917  * @drop: caps being dropped
4918  * @unless: unless we have these caps
4919  *
4920  * Encode a dentry release into an outgoing request buffer. Returns 1 if the
4921  * thing was released, or a negative error code otherwise.
4922  */
4923 int ceph_encode_dentry_release(void **p, struct dentry *dentry,
4924                                struct inode *dir,
4925                                int mds, int drop, int unless)
4926 {
4927         struct ceph_mds_request_release *rel = *p;
4928         struct ceph_dentry_info *di = ceph_dentry(dentry);
4929         struct ceph_client *cl;
4930         int force = 0;
4931         int ret;
4932 
4933         /* This shouldn't happen */
4934         BUG_ON(!dir);
4935 
4936         /*
4937          * force an record for the directory caps if we have a dentry lease.
4938          * this is racy (can't take i_ceph_lock and d_lock together), but it
4939          * doesn't have to be perfect; the mds will revoke anything we don't
4940          * release.
4941          */
4942         spin_lock(&dentry->d_lock);
4943         if (di->lease_session && di->lease_session->s_mds == mds)
4944                 force = 1;
4945         spin_unlock(&dentry->d_lock);
4946 
4947         ret = ceph_encode_inode_release(p, dir, mds, drop, unless, force);
4948 
4949         cl = ceph_inode_to_client(dir);
4950         spin_lock(&dentry->d_lock);
4951         if (ret && di->lease_session && di->lease_session->s_mds == mds) {
4952                 doutc(cl, "%p mds%d seq %d\n",  dentry, mds,
4953                       (int)di->lease_seq);
4954                 rel->dname_seq = cpu_to_le32(di->lease_seq);
4955                 __ceph_mdsc_drop_dentry_lease(dentry);
4956                 spin_unlock(&dentry->d_lock);
4957                 if (IS_ENCRYPTED(dir) && fscrypt_has_encryption_key(dir)) {
4958                         int ret2 = ceph_encode_encrypted_fname(dir, dentry, *p);
4959 
4960                         if (ret2 < 0)
4961                                 return ret2;
4962 
4963                         rel->dname_len = cpu_to_le32(ret2);
4964                         *p += ret2;
4965                 } else {
4966                         rel->dname_len = cpu_to_le32(dentry->d_name.len);
4967                         memcpy(*p, dentry->d_name.name, dentry->d_name.len);
4968                         *p += dentry->d_name.len;
4969                 }
4970         } else {
4971                 spin_unlock(&dentry->d_lock);
4972         }
4973         return ret;
4974 }
4975 
4976 static int remove_capsnaps(struct ceph_mds_client *mdsc, struct inode *inode)
4977 {
4978         struct ceph_inode_info *ci = ceph_inode(inode);
4979         struct ceph_client *cl = mdsc->fsc->client;
4980         struct ceph_cap_snap *capsnap;
4981         int capsnap_release = 0;
4982 
4983         lockdep_assert_held(&ci->i_ceph_lock);
4984 
4985         doutc(cl, "removing capsnaps, ci is %p, %p %llx.%llx\n",
4986               ci, inode, ceph_vinop(inode));
4987 
4988         while (!list_empty(&ci->i_cap_snaps)) {
4989                 capsnap = list_first_entry(&ci->i_cap_snaps,
4990                                            struct ceph_cap_snap, ci_item);
4991                 __ceph_remove_capsnap(inode, capsnap, NULL, NULL);
4992                 ceph_put_snap_context(capsnap->context);
4993                 ceph_put_cap_snap(capsnap);
4994                 capsnap_release++;
4995         }
4996         wake_up_all(&ci->i_cap_wq);
4997         wake_up_all(&mdsc->cap_flushing_wq);
4998         return capsnap_release;
4999 }
5000 
5001 int ceph_purge_inode_cap(struct inode *inode, struct ceph_cap *cap, bool *invalidate)
5002 {
5003         struct ceph_fs_client *fsc = ceph_inode_to_fs_client(inode);
5004         struct ceph_mds_client *mdsc = fsc->mdsc;
5005         struct ceph_client *cl = fsc->client;
5006         struct ceph_inode_info *ci = ceph_inode(inode);
5007         bool is_auth;
5008         bool dirty_dropped = false;
5009         int iputs = 0;
5010 
5011         lockdep_assert_held(&ci->i_ceph_lock);
5012 
5013         doutc(cl, "removing cap %p, ci is %p, %p %llx.%llx\n",
5014               cap, ci, inode, ceph_vinop(inode));
5015 
5016         is_auth = (cap == ci->i_auth_cap);
5017         __ceph_remove_cap(cap, false);
5018         if (is_auth) {
5019                 struct ceph_cap_flush *cf;
5020 
5021                 if (ceph_inode_is_shutdown(inode)) {
5022                         if (inode->i_data.nrpages > 0)
5023                                 *invalidate = true;
5024                         if (ci->i_wrbuffer_ref > 0)
5025                                 mapping_set_error(&inode->i_data, -EIO);
5026                 }
5027 
5028                 spin_lock(&mdsc->cap_dirty_lock);
5029 
5030                 /* trash all of the cap flushes for this inode */
5031                 while (!list_empty(&ci->i_cap_flush_list)) {
5032                         cf = list_first_entry(&ci->i_cap_flush_list,
5033                                               struct ceph_cap_flush, i_list);
5034                         list_del_init(&cf->g_list);
5035                         list_del_init(&cf->i_list);
5036                         if (!cf->is_capsnap)
5037                                 ceph_free_cap_flush(cf);
5038                 }
5039 
5040                 if (!list_empty(&ci->i_dirty_item)) {
5041                         pr_warn_ratelimited_client(cl,
5042                                 " dropping dirty %s state for %p %llx.%llx\n",
5043                                 ceph_cap_string(ci->i_dirty_caps),
5044                                 inode, ceph_vinop(inode));
5045                         ci->i_dirty_caps = 0;
5046                         list_del_init(&ci->i_dirty_item);
5047                         dirty_dropped = true;
5048                 }
5049                 if (!list_empty(&ci->i_flushing_item)) {
5050                         pr_warn_ratelimited_client(cl,
5051                                 " dropping dirty+flushing %s state for %p %llx.%llx\n",
5052                                 ceph_cap_string(ci->i_flushing_caps),
5053                                 inode, ceph_vinop(inode));
5054                         ci->i_flushing_caps = 0;
5055                         list_del_init(&ci->i_flushing_item);
5056                         mdsc->num_cap_flushing--;
5057                         dirty_dropped = true;
5058                 }
5059                 spin_unlock(&mdsc->cap_dirty_lock);
5060 
5061                 if (dirty_dropped) {
5062                         mapping_set_error(inode->i_mapping, -EIO);
5063 
5064                         if (ci->i_wrbuffer_ref_head == 0 &&
5065                             ci->i_wr_ref == 0 &&
5066                             ci->i_dirty_caps == 0 &&
5067                             ci->i_flushing_caps == 0) {
5068                                 ceph_put_snap_context(ci->i_head_snapc);
5069                                 ci->i_head_snapc = NULL;
5070                         }
5071                 }
5072 
5073                 if (atomic_read(&ci->i_filelock_ref) > 0) {
5074                         /* make further file lock syscall return -EIO */
5075                         ci->i_ceph_flags |= CEPH_I_ERROR_FILELOCK;
5076                         pr_warn_ratelimited_client(cl,
5077                                 " dropping file locks for %p %llx.%llx\n",
5078                                 inode, ceph_vinop(inode));
5079                 }
5080 
5081                 if (!ci->i_dirty_caps && ci->i_prealloc_cap_flush) {
5082                         cf = ci->i_prealloc_cap_flush;
5083                         ci->i_prealloc_cap_flush = NULL;
5084                         if (!cf->is_capsnap)
5085                                 ceph_free_cap_flush(cf);
5086                 }
5087 
5088                 if (!list_empty(&ci->i_cap_snaps))
5089                         iputs = remove_capsnaps(mdsc, inode);
5090         }
5091         if (dirty_dropped)
5092                 ++iputs;
5093         return iputs;
5094 }
5095 

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