1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6 #ifndef __XFS_ATTR_H__
7 #define __XFS_ATTR_H__
8
9 struct xfs_inode;
10 struct xfs_da_args;
11 struct xfs_attr_list_context;
12
13 /*
14 * Large attribute lists are structured around Btrees where all the data
15 * elements are in the leaf nodes. Attribute names are hashed into an int,
16 * then that int is used as the index into the Btree. Since the hashval
17 * of an attribute name may not be unique, we may have duplicate keys.
18 * The internal links in the Btree are logical block offsets into the file.
19 *
20 * Small attribute lists use a different format and are packed as tightly
21 * as possible so as to fit into the literal area of the inode.
22 */
23
24 /*
25 * The maximum size (into the kernel or returned from the kernel) of an
26 * attribute value or the buffer used for an attr_list() call. Larger
27 * sizes will result in an ERANGE return code.
28 */
29 #define ATTR_MAX_VALUELEN (64*1024) /* max length of a value */
30
31 /*
32 * Kernel-internal version of the attrlist cursor.
33 */
34 struct xfs_attrlist_cursor_kern {
35 __u32 hashval; /* hash value of next entry to add */
36 __u32 blkno; /* block containing entry (suggestion) */
37 __u32 offset; /* offset in list of equal-hashvals */
38 __u16 pad1; /* padding to match user-level */
39 __u8 pad2; /* padding to match user-level */
40 __u8 initted; /* T/F: cursor has been initialized */
41 };
42
43
44 /*========================================================================
45 * Structure used to pass context around among the routines.
46 *========================================================================*/
47
48
49 /* void; state communicated via *context */
50 typedef void (*put_listent_func_t)(struct xfs_attr_list_context *context,
51 int flags, unsigned char *name, int namelen, void *value,
52 int valuelen);
53
54 struct xfs_attr_list_context {
55 struct xfs_trans *tp;
56 struct xfs_inode *dp; /* inode */
57 struct xfs_attrlist_cursor_kern cursor; /* position in list */
58 void *buffer; /* output buffer */
59
60 /*
61 * Abort attribute list iteration if non-zero. Can be used to pass
62 * error values to the xfs_attr_list caller.
63 */
64 int seen_enough;
65 bool allow_incomplete;
66
67 ssize_t count; /* num used entries */
68 int dupcnt; /* count dup hashvals seen */
69 int bufsize; /* total buffer size */
70 int firstu; /* first used byte in buffer */
71 unsigned int attr_filter; /* XFS_ATTR_{ROOT,SECURE} */
72 int resynch; /* T/F: resynch with cursor */
73 put_listent_func_t put_listent; /* list output fmt function */
74 int index; /* index into output buffer */
75 };
76
77
78 /*
79 * ========================================================================
80 * Structure used to pass context around among the delayed routines.
81 * ========================================================================
82 */
83
84 /*
85 * Below is a state machine diagram for attr remove operations. The XFS_DAS_*
86 * states indicate places where the function would return -EAGAIN, and then
87 * immediately resume from after being called by the calling function. States
88 * marked as a "subroutine state" indicate that they belong to a subroutine, and
89 * so the calling function needs to pass them back to that subroutine to allow
90 * it to finish where it left off. But they otherwise do not have a role in the
91 * calling function other than just passing through.
92 *
93 * xfs_attr_remove_iter()
94 * │
95 * v
96 * have attr to remove? ──n──> done
97 * │
98 * y
99 * │
100 * v
101 * are we short form? ──y──> xfs_attr_shortform_remove ──> done
102 * │
103 * n
104 * │
105 * V
106 * are we leaf form? ──y──> xfs_attr_leaf_removename ──> done
107 * │
108 * n
109 * │
110 * V
111 * ┌── need to setup state?
112 * │ │
113 * n y
114 * │ │
115 * │ v
116 * │ find attr and get state
117 * │ attr has remote blks? ──n─┐
118 * │ │ v
119 * │ │ find and invalidate
120 * │ y the remote blocks.
121 * │ │ mark attr incomplete
122 * │ ├────────────────┘
123 * └──────────┤
124 * │
125 * v
126 * Have remote blks to remove? ───y─────┐
127 * │ ^ remove the blks
128 * │ │ │
129 * │ │ v
130 * │ XFS_DAS_RMTBLK <─n── done?
131 * │ re-enter with │
132 * │ one less blk to y
133 * │ remove │
134 * │ V
135 * │ refill the state
136 * n │
137 * │ v
138 * │ XFS_DAS_RM_NAME
139 * │ │
140 * ├─────────────────────────┘
141 * │
142 * v
143 * remove leaf and
144 * update hash with
145 * xfs_attr_node_remove_cleanup
146 * │
147 * v
148 * need to
149 * shrink tree? ─n─┐
150 * │ │
151 * y │
152 * │ │
153 * v │
154 * join leaf │
155 * │ │
156 * v │
157 * XFS_DAS_RM_SHRINK │
158 * │ │
159 * v │
160 * do the shrink │
161 * │ │
162 * v │
163 * free state <──┘
164 * │
165 * v
166 * done
167 *
168 *
169 * Below is a state machine diagram for attr set operations.
170 *
171 * It seems the challenge with understanding this system comes from trying to
172 * absorb the state machine all at once, when really one should only be looking
173 * at it with in the context of a single function. Once a state sensitive
174 * function is called, the idea is that it "takes ownership" of the
175 * state machine. It isn't concerned with the states that may have belonged to
176 * it's calling parent. Only the states relevant to itself or any other
177 * subroutines there in. Once a calling function hands off the state machine to
178 * a subroutine, it needs to respect the simple rule that it doesn't "own" the
179 * state machine anymore, and it's the responsibility of that calling function
180 * to propagate the -EAGAIN back up the call stack. Upon reentry, it is
181 * committed to re-calling that subroutine until it returns something other than
182 * -EAGAIN. Once that subroutine signals completion (by returning anything other
183 * than -EAGAIN), the calling function can resume using the state machine.
184 *
185 * xfs_attr_set_iter()
186 * │
187 * v
188 * ┌─y─ has an attr fork?
189 * │ |
190 * │ n
191 * │ |
192 * │ V
193 * │ add a fork
194 * │ │
195 * └──────────┤
196 * │
197 * V
198 * ┌─── is shortform?
199 * │ │
200 * │ y
201 * │ │
202 * │ V
203 * │ xfs_attr_set_fmt
204 * │ |
205 * │ V
206 * │ xfs_attr_try_sf_addname
207 * │ │
208 * │ V
209 * │ had enough ──y──> done
210 * │ space?
211 * n │
212 * │ n
213 * │ │
214 * │ V
215 * │ transform to leaf
216 * │ │
217 * │ V
218 * │ hold the leaf buffer
219 * │ │
220 * │ V
221 * │ return -EAGAIN
222 * │ Re-enter in
223 * │ leaf form
224 * │
225 * └─> release leaf buffer
226 * if needed
227 * │
228 * V
229 * ┌───n── fork has
230 * │ only 1 blk?
231 * │ │
232 * │ y
233 * │ │
234 * │ v
235 * │ xfs_attr_leaf_try_add()
236 * │ │
237 * │ v
238 * │ had enough ──────────────y─────────────┐
239 * │ space? │
240 * │ │ │
241 * │ n │
242 * │ │ │
243 * │ v │
244 * │ return -EAGAIN │
245 * │ re-enter in │
246 * │ node form │
247 * │ │ │
248 * └──────────┤ │
249 * │ │
250 * V │
251 * xfs_attr_node_addname_find_attr │
252 * determines if this │
253 * is create or rename │
254 * find space to store attr │
255 * │ │
256 * v │
257 * xfs_attr_node_addname │
258 * │ │
259 * v │
260 * fits in a node leaf? ────n─────┐ │
261 * │ ^ v │
262 * │ │ single leaf node? │
263 * │ │ │ │ │
264 * y │ y n │
265 * │ │ │ │ │
266 * v │ v v │
267 * update │ grow the leaf split if │
268 * hashvals └── return -EAGAIN needed │
269 * │ retry leaf add │ │
270 * │ on reentry │ │
271 * ├────────────────────────────┘ │
272 * │ │
273 * v │
274 * need to alloc │
275 * ┌─y── or flip flag? │
276 * │ │ │
277 * │ n │
278 * │ │ │
279 * │ v │
280 * │ done │
281 * │ │
282 * │ │
283 * │ XFS_DAS_FOUND_LBLK <────────────────┘
284 * │ │
285 * │ V
286 * │ xfs_attr_leaf_addname()
287 * │ │
288 * │ v
289 * │ ┌──first time through?
290 * │ │ │
291 * │ │ y
292 * │ │ │
293 * │ n v
294 * │ │ if we have rmt blks
295 * │ │ find space for them
296 * │ │ │
297 * │ └──────────┤
298 * │ │
299 * │ v
300 * │ still have
301 * │ ┌─n─ blks to alloc? <──┐
302 * │ │ │ │
303 * │ │ y │
304 * │ │ │ │
305 * │ │ v │
306 * │ │ alloc one blk │
307 * │ │ return -EAGAIN ──┘
308 * │ │ re-enter with one
309 * │ │ less blk to alloc
310 * │ │
311 * │ │
312 * │ └───> set the rmt
313 * │ value
314 * │ │
315 * │ v
316 * │ was this
317 * │ a rename? ──n─┐
318 * │ │ │
319 * │ y │
320 * │ │ │
321 * │ v │
322 * │ flip incomplete │
323 * │ flag │
324 * │ │ │
325 * │ v │
326 * │ XFS_DAS_FLIP_LFLAG │
327 * │ │ │
328 * │ v │
329 * │ need to remove │
330 * │ old bks? ──n──┤
331 * │ │ │
332 * │ y │
333 * │ │ │
334 * │ V │
335 * │ remove │
336 * │ ┌───> old blks │
337 * │ │ │ │
338 * │ XFS_DAS_RM_LBLK │ │
339 * │ ^ │ │
340 * │ │ v │
341 * │ └──y── more to │
342 * │ remove? │
343 * │ │ │
344 * │ n │
345 * │ │ │
346 * │ v │
347 * │ XFS_DAS_RD_LEAF │
348 * │ │ │
349 * │ v │
350 * │ remove leaf │
351 * │ │ │
352 * │ v │
353 * │ shrink to sf │
354 * │ if needed │
355 * │ │ │
356 * │ v │
357 * │ done <──────┘
358 * │
359 * └──────> XFS_DAS_FOUND_NBLK
360 * │
361 * v
362 * ┌─────n── need to
363 * │ alloc blks?
364 * │ │
365 * │ y
366 * │ │
367 * │ v
368 * │ find space
369 * │ │
370 * │ v
371 * │ ┌─>XFS_DAS_ALLOC_NODE
372 * │ │ │
373 * │ │ v
374 * │ │ alloc blk
375 * │ │ │
376 * │ │ v
377 * │ └──y── need to alloc
378 * │ more blocks?
379 * │ │
380 * │ n
381 * │ │
382 * │ v
383 * │ set the rmt value
384 * │ │
385 * │ v
386 * │ was this
387 * └────────> a rename? ──n─┐
388 * │ │
389 * y │
390 * │ │
391 * v │
392 * flip incomplete │
393 * flag │
394 * │ │
395 * v │
396 * XFS_DAS_FLIP_NFLAG │
397 * │ │
398 * v │
399 * need to │
400 * remove blks? ─n──┤
401 * │ │
402 * y │
403 * │ │
404 * v │
405 * remove │
406 * ┌────────> old blks │
407 * │ │ │
408 * XFS_DAS_RM_NBLK │ │
409 * ^ │ │
410 * │ v │
411 * └──────y── more to │
412 * remove │
413 * │ │
414 * n │
415 * │ │
416 * v │
417 * XFS_DAS_CLR_FLAG │
418 * │ │
419 * v │
420 * clear flags │
421 * │ │
422 * ├──────────┘
423 * │
424 * v
425 * done
426 */
427
428 /*
429 * Enum values for xfs_attr_intent.xattri_da_state
430 *
431 * These values are used by delayed attribute operations to keep track of where
432 * they were before they returned -EAGAIN. A return code of -EAGAIN signals the
433 * calling function to roll the transaction, and then call the subroutine to
434 * finish the operation. The enum is then used by the subroutine to jump back
435 * to where it was and resume executing where it left off.
436 */
437 enum xfs_delattr_state {
438 XFS_DAS_UNINIT = 0, /* No state has been set yet */
439
440 /*
441 * Initial sequence states. The replace setup code relies on the
442 * ADD and REMOVE states for a specific format to be sequential so
443 * that we can transform the initial operation to be performed
444 * according to the xfs_has_larp() state easily.
445 */
446 XFS_DAS_SF_ADD, /* Initial sf add state */
447 XFS_DAS_SF_REMOVE, /* Initial sf replace/remove state */
448
449 XFS_DAS_LEAF_ADD, /* Initial leaf add state */
450 XFS_DAS_LEAF_REMOVE, /* Initial leaf replace/remove state */
451
452 XFS_DAS_NODE_ADD, /* Initial node add state */
453 XFS_DAS_NODE_REMOVE, /* Initial node replace/remove state */
454
455 /* Leaf state set/replace/remove sequence */
456 XFS_DAS_LEAF_SET_RMT, /* set a remote xattr from a leaf */
457 XFS_DAS_LEAF_ALLOC_RMT, /* We are allocating remote blocks */
458 XFS_DAS_LEAF_REPLACE, /* Perform replace ops on a leaf */
459 XFS_DAS_LEAF_REMOVE_OLD, /* Start removing old attr from leaf */
460 XFS_DAS_LEAF_REMOVE_RMT, /* A rename is removing remote blocks */
461 XFS_DAS_LEAF_REMOVE_ATTR, /* Remove the old attr from a leaf */
462
463 /* Node state sequence, must match leaf state above */
464 XFS_DAS_NODE_SET_RMT, /* set a remote xattr from a node */
465 XFS_DAS_NODE_ALLOC_RMT, /* We are allocating remote blocks */
466 XFS_DAS_NODE_REPLACE, /* Perform replace ops on a node */
467 XFS_DAS_NODE_REMOVE_OLD, /* Start removing old attr from node */
468 XFS_DAS_NODE_REMOVE_RMT, /* A rename is removing remote blocks */
469 XFS_DAS_NODE_REMOVE_ATTR, /* Remove the old attr from a node */
470
471 XFS_DAS_DONE, /* finished operation */
472 };
473
474 #define XFS_DAS_STRINGS \
475 { XFS_DAS_UNINIT, "XFS_DAS_UNINIT" }, \
476 { XFS_DAS_SF_ADD, "XFS_DAS_SF_ADD" }, \
477 { XFS_DAS_SF_REMOVE, "XFS_DAS_SF_REMOVE" }, \
478 { XFS_DAS_LEAF_ADD, "XFS_DAS_LEAF_ADD" }, \
479 { XFS_DAS_LEAF_REMOVE, "XFS_DAS_LEAF_REMOVE" }, \
480 { XFS_DAS_NODE_ADD, "XFS_DAS_NODE_ADD" }, \
481 { XFS_DAS_NODE_REMOVE, "XFS_DAS_NODE_REMOVE" }, \
482 { XFS_DAS_LEAF_SET_RMT, "XFS_DAS_LEAF_SET_RMT" }, \
483 { XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \
484 { XFS_DAS_LEAF_REPLACE, "XFS_DAS_LEAF_REPLACE" }, \
485 { XFS_DAS_LEAF_REMOVE_OLD, "XFS_DAS_LEAF_REMOVE_OLD" }, \
486 { XFS_DAS_LEAF_REMOVE_RMT, "XFS_DAS_LEAF_REMOVE_RMT" }, \
487 { XFS_DAS_LEAF_REMOVE_ATTR, "XFS_DAS_LEAF_REMOVE_ATTR" }, \
488 { XFS_DAS_NODE_SET_RMT, "XFS_DAS_NODE_SET_RMT" }, \
489 { XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" }, \
490 { XFS_DAS_NODE_REPLACE, "XFS_DAS_NODE_REPLACE" }, \
491 { XFS_DAS_NODE_REMOVE_OLD, "XFS_DAS_NODE_REMOVE_OLD" }, \
492 { XFS_DAS_NODE_REMOVE_RMT, "XFS_DAS_NODE_REMOVE_RMT" }, \
493 { XFS_DAS_NODE_REMOVE_ATTR, "XFS_DAS_NODE_REMOVE_ATTR" }, \
494 { XFS_DAS_DONE, "XFS_DAS_DONE" }
495
496 struct xfs_attri_log_nameval;
497
498 /*
499 * Context used for keeping track of delayed attribute operations
500 */
501 struct xfs_attr_intent {
502 /*
503 * used to log this item to an intent containing a list of attrs to
504 * commit later
505 */
506 struct list_head xattri_list;
507
508 /* Used in xfs_attr_node_removename to roll through removing blocks */
509 struct xfs_da_state *xattri_da_state;
510
511 struct xfs_da_args *xattri_da_args;
512
513 /*
514 * Shared buffer containing the attr name, new name, and value so that
515 * the logging code can share large memory buffers between log items.
516 */
517 struct xfs_attri_log_nameval *xattri_nameval;
518
519 /* Used to keep track of current state of delayed operation */
520 enum xfs_delattr_state xattri_dela_state;
521
522 /*
523 * Attr operation being performed - XFS_ATTRI_OP_FLAGS_*
524 */
525 unsigned int xattri_op_flags;
526
527 /* Used in xfs_attr_rmtval_set_blk to roll through allocating blocks */
528 xfs_dablk_t xattri_lblkno;
529 int xattri_blkcnt;
530 struct xfs_bmbt_irec xattri_map;
531 };
532
533 static inline unsigned int
534 xfs_attr_intent_op(const struct xfs_attr_intent *attr)
535 {
536 return attr->xattri_op_flags & XFS_ATTRI_OP_FLAGS_TYPE_MASK;
537 }
538
539 /*========================================================================
540 * Function prototypes for the kernel.
541 *========================================================================*/
542
543 /*
544 * Overall external interface routines.
545 */
546 int xfs_attr_inactive(struct xfs_inode *dp);
547 int xfs_attr_list_ilocked(struct xfs_attr_list_context *);
548 int xfs_attr_list(struct xfs_attr_list_context *);
549 int xfs_inode_hasattr(struct xfs_inode *ip);
550 bool xfs_attr_is_leaf(struct xfs_inode *ip);
551 int xfs_attr_get_ilocked(struct xfs_da_args *args);
552 int xfs_attr_get(struct xfs_da_args *args);
553
554 enum xfs_attr_update {
555 XFS_ATTRUPDATE_REMOVE, /* remove attr */
556 XFS_ATTRUPDATE_UPSERT, /* set value, replace any existing attr */
557 XFS_ATTRUPDATE_CREATE, /* set value, fail if attr already exists */
558 XFS_ATTRUPDATE_REPLACE, /* set value, fail if attr does not exist */
559 };
560
561 int xfs_attr_set(struct xfs_da_args *args, enum xfs_attr_update op, bool rsvd);
562 int xfs_attr_set_iter(struct xfs_attr_intent *attr);
563 int xfs_attr_remove_iter(struct xfs_attr_intent *attr);
564 bool xfs_attr_check_namespace(unsigned int attr_flags);
565 bool xfs_attr_namecheck(unsigned int attr_flags, const void *name,
566 size_t length);
567 int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
568 struct xfs_trans_res xfs_attr_set_resv(const struct xfs_da_args *args);
569
570 /*
571 * Check to see if the attr should be upgraded from non-existent or shortform to
572 * single-leaf-block attribute list.
573 */
574 static inline bool
575 xfs_attr_is_shortform(
576 struct xfs_inode *ip)
577 {
578 return ip->i_af.if_format == XFS_DINODE_FMT_LOCAL ||
579 (ip->i_af.if_format == XFS_DINODE_FMT_EXTENTS &&
580 ip->i_af.if_nextents == 0);
581 }
582
583 static inline enum xfs_delattr_state
584 xfs_attr_init_add_state(struct xfs_da_args *args)
585 {
586 /*
587 * When called from the completion of a attr remove to determine the
588 * next state, the attribute fork may be null. This can occur only occur
589 * on a pure remove, but we grab the next state before we check if a
590 * replace operation is being performed. If we are called from any other
591 * context, i_af is guaranteed to exist. Hence if the attr fork is
592 * null, we were called from a pure remove operation and so we are done.
593 */
594 if (!xfs_inode_has_attr_fork(args->dp))
595 return XFS_DAS_DONE;
596
597 args->op_flags |= XFS_DA_OP_ADDNAME;
598 if (xfs_attr_is_shortform(args->dp))
599 return XFS_DAS_SF_ADD;
600 if (xfs_attr_is_leaf(args->dp))
601 return XFS_DAS_LEAF_ADD;
602 return XFS_DAS_NODE_ADD;
603 }
604
605 static inline enum xfs_delattr_state
606 xfs_attr_init_remove_state(struct xfs_da_args *args)
607 {
608 if (xfs_attr_is_shortform(args->dp))
609 return XFS_DAS_SF_REMOVE;
610 if (xfs_attr_is_leaf(args->dp))
611 return XFS_DAS_LEAF_REMOVE;
612 return XFS_DAS_NODE_REMOVE;
613 }
614
615 /*
616 * If we are logging the attributes, then we have to start with removal of the
617 * old attribute so that there is always consistent state that we can recover
618 * from if the system goes down part way through. We always log the new attr
619 * value, so even when we remove the attr first we still have the information in
620 * the log to finish the replace operation atomically.
621 */
622 static inline enum xfs_delattr_state
623 xfs_attr_init_replace_state(struct xfs_da_args *args)
624 {
625 args->op_flags |= XFS_DA_OP_ADDNAME | XFS_DA_OP_REPLACE;
626 if (args->op_flags & XFS_DA_OP_LOGGED)
627 return xfs_attr_init_remove_state(args);
628 return xfs_attr_init_add_state(args);
629 }
630
631 xfs_dahash_t xfs_attr_hashname(const uint8_t *name, int namelen);
632
633 xfs_dahash_t xfs_attr_hashval(struct xfs_mount *mp, unsigned int attr_flags,
634 const uint8_t *name, int namelen, const void *value,
635 int valuelen);
636
637 /* Set the hash value for any extended attribute from any namespace. */
638 static inline void xfs_attr_sethash(struct xfs_da_args *args)
639 {
640 args->hashval = xfs_attr_hashval(args->dp->i_mount, args->attr_filter,
641 args->name, args->namelen,
642 args->value, args->valuelen);
643 }
644
645 extern struct kmem_cache *xfs_attr_intent_cache;
646 int __init xfs_attr_intent_init_cache(void);
647 void xfs_attr_intent_destroy_cache(void);
648
649 int xfs_attr_sf_totsize(struct xfs_inode *dp);
650 int xfs_attr_add_fork(struct xfs_inode *ip, int size, int rsvd);
651
652 #endif /* __XFS_ATTR_H__ */
653
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