1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * vfsv0 quota IO operations on file
4 */
5
6 #include <linux/errno.h>
7 #include <linux/fs.h>
8 #include <linux/mount.h>
9 #include <linux/dqblk_v2.h>
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/quotaops.h>
15
16 #include <asm/byteorder.h>
17
18 #include "quota_tree.h"
19
20 MODULE_AUTHOR("Jan Kara");
21 MODULE_DESCRIPTION("Quota trie support");
22 MODULE_LICENSE("GPL");
23
24 /*
25 * Maximum quota tree depth we support. Only to limit recursion when working
26 * with the tree.
27 */
28 #define MAX_QTREE_DEPTH 6
29
30 #define __QUOTA_QT_PARANOIA
31
32 static int __get_index(struct qtree_mem_dqinfo *info, qid_t id, int depth)
33 {
34 unsigned int epb = info->dqi_usable_bs >> 2;
35
36 depth = info->dqi_qtree_depth - depth - 1;
37 while (depth--)
38 id /= epb;
39 return id % epb;
40 }
41
42 static int get_index(struct qtree_mem_dqinfo *info, struct kqid qid, int depth)
43 {
44 qid_t id = from_kqid(&init_user_ns, qid);
45
46 return __get_index(info, id, depth);
47 }
48
49 /* Number of entries in one blocks */
50 static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info)
51 {
52 return (info->dqi_usable_bs - sizeof(struct qt_disk_dqdbheader))
53 / info->dqi_entry_size;
54 }
55
56 static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
57 {
58 struct super_block *sb = info->dqi_sb;
59
60 memset(buf, 0, info->dqi_usable_bs);
61 return sb->s_op->quota_read(sb, info->dqi_type, buf,
62 info->dqi_usable_bs, (loff_t)blk << info->dqi_blocksize_bits);
63 }
64
65 static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
66 {
67 struct super_block *sb = info->dqi_sb;
68 ssize_t ret;
69
70 ret = sb->s_op->quota_write(sb, info->dqi_type, buf,
71 info->dqi_usable_bs, (loff_t)blk << info->dqi_blocksize_bits);
72 if (ret != info->dqi_usable_bs) {
73 quota_error(sb, "dquota write failed");
74 if (ret >= 0)
75 ret = -EIO;
76 }
77 return ret;
78 }
79
80 static inline int do_check_range(struct super_block *sb, const char *val_name,
81 uint val, uint min_val, uint max_val)
82 {
83 if (val < min_val || val > max_val) {
84 quota_error(sb, "Getting %s %u out of range %u-%u",
85 val_name, val, min_val, max_val);
86 return -EUCLEAN;
87 }
88
89 return 0;
90 }
91
92 static int check_dquot_block_header(struct qtree_mem_dqinfo *info,
93 struct qt_disk_dqdbheader *dh)
94 {
95 int err = 0;
96
97 err = do_check_range(info->dqi_sb, "dqdh_next_free",
98 le32_to_cpu(dh->dqdh_next_free), 0,
99 info->dqi_blocks - 1);
100 if (err)
101 return err;
102 err = do_check_range(info->dqi_sb, "dqdh_prev_free",
103 le32_to_cpu(dh->dqdh_prev_free), 0,
104 info->dqi_blocks - 1);
105 if (err)
106 return err;
107 err = do_check_range(info->dqi_sb, "dqdh_entries",
108 le16_to_cpu(dh->dqdh_entries), 0,
109 qtree_dqstr_in_blk(info));
110
111 return err;
112 }
113
114 /* Remove empty block from list and return it */
115 static int get_free_dqblk(struct qtree_mem_dqinfo *info)
116 {
117 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
118 struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
119 int ret, blk;
120
121 if (!buf)
122 return -ENOMEM;
123 if (info->dqi_free_blk) {
124 blk = info->dqi_free_blk;
125 ret = read_blk(info, blk, buf);
126 if (ret < 0)
127 goto out_buf;
128 ret = check_dquot_block_header(info, dh);
129 if (ret)
130 goto out_buf;
131 info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
132 }
133 else {
134 memset(buf, 0, info->dqi_usable_bs);
135 /* Assure block allocation... */
136 ret = write_blk(info, info->dqi_blocks, buf);
137 if (ret < 0)
138 goto out_buf;
139 blk = info->dqi_blocks++;
140 }
141 mark_info_dirty(info->dqi_sb, info->dqi_type);
142 ret = blk;
143 out_buf:
144 kfree(buf);
145 return ret;
146 }
147
148 /* Insert empty block to the list */
149 static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk)
150 {
151 struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
152 int err;
153
154 dh->dqdh_next_free = cpu_to_le32(info->dqi_free_blk);
155 dh->dqdh_prev_free = cpu_to_le32(0);
156 dh->dqdh_entries = cpu_to_le16(0);
157 err = write_blk(info, blk, buf);
158 if (err < 0)
159 return err;
160 info->dqi_free_blk = blk;
161 mark_info_dirty(info->dqi_sb, info->dqi_type);
162 return 0;
163 }
164
165 /* Remove given block from the list of blocks with free entries */
166 static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
167 uint blk)
168 {
169 char *tmpbuf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
170 struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
171 uint nextblk = le32_to_cpu(dh->dqdh_next_free);
172 uint prevblk = le32_to_cpu(dh->dqdh_prev_free);
173 int err;
174
175 if (!tmpbuf)
176 return -ENOMEM;
177 if (nextblk) {
178 err = read_blk(info, nextblk, tmpbuf);
179 if (err < 0)
180 goto out_buf;
181 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
182 dh->dqdh_prev_free;
183 err = write_blk(info, nextblk, tmpbuf);
184 if (err < 0)
185 goto out_buf;
186 }
187 if (prevblk) {
188 err = read_blk(info, prevblk, tmpbuf);
189 if (err < 0)
190 goto out_buf;
191 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free =
192 dh->dqdh_next_free;
193 err = write_blk(info, prevblk, tmpbuf);
194 if (err < 0)
195 goto out_buf;
196 } else {
197 info->dqi_free_entry = nextblk;
198 mark_info_dirty(info->dqi_sb, info->dqi_type);
199 }
200 kfree(tmpbuf);
201 dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
202 /* No matter whether write succeeds block is out of list */
203 if (write_blk(info, blk, buf) < 0)
204 quota_error(info->dqi_sb, "Can't write block (%u) "
205 "with free entries", blk);
206 return 0;
207 out_buf:
208 kfree(tmpbuf);
209 return err;
210 }
211
212 /* Insert given block to the beginning of list with free entries */
213 static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
214 uint blk)
215 {
216 char *tmpbuf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
217 struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
218 int err;
219
220 if (!tmpbuf)
221 return -ENOMEM;
222 dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry);
223 dh->dqdh_prev_free = cpu_to_le32(0);
224 err = write_blk(info, blk, buf);
225 if (err < 0)
226 goto out_buf;
227 if (info->dqi_free_entry) {
228 err = read_blk(info, info->dqi_free_entry, tmpbuf);
229 if (err < 0)
230 goto out_buf;
231 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
232 cpu_to_le32(blk);
233 err = write_blk(info, info->dqi_free_entry, tmpbuf);
234 if (err < 0)
235 goto out_buf;
236 }
237 kfree(tmpbuf);
238 info->dqi_free_entry = blk;
239 mark_info_dirty(info->dqi_sb, info->dqi_type);
240 return 0;
241 out_buf:
242 kfree(tmpbuf);
243 return err;
244 }
245
246 /* Is the entry in the block free? */
247 int qtree_entry_unused(struct qtree_mem_dqinfo *info, char *disk)
248 {
249 int i;
250
251 for (i = 0; i < info->dqi_entry_size; i++)
252 if (disk[i])
253 return 0;
254 return 1;
255 }
256 EXPORT_SYMBOL(qtree_entry_unused);
257
258 /* Find space for dquot */
259 static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
260 struct dquot *dquot, int *err)
261 {
262 uint blk, i;
263 struct qt_disk_dqdbheader *dh;
264 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
265 char *ddquot;
266
267 *err = 0;
268 if (!buf) {
269 *err = -ENOMEM;
270 return 0;
271 }
272 dh = (struct qt_disk_dqdbheader *)buf;
273 if (info->dqi_free_entry) {
274 blk = info->dqi_free_entry;
275 *err = read_blk(info, blk, buf);
276 if (*err < 0)
277 goto out_buf;
278 *err = check_dquot_block_header(info, dh);
279 if (*err)
280 goto out_buf;
281 } else {
282 blk = get_free_dqblk(info);
283 if ((int)blk < 0) {
284 *err = blk;
285 kfree(buf);
286 return 0;
287 }
288 memset(buf, 0, info->dqi_usable_bs);
289 /* This is enough as the block is already zeroed and the entry
290 * list is empty... */
291 info->dqi_free_entry = blk;
292 mark_info_dirty(dquot->dq_sb, dquot->dq_id.type);
293 }
294 /* Block will be full? */
295 if (le16_to_cpu(dh->dqdh_entries) + 1 >= qtree_dqstr_in_blk(info)) {
296 *err = remove_free_dqentry(info, buf, blk);
297 if (*err < 0) {
298 quota_error(dquot->dq_sb, "Can't remove block (%u) "
299 "from entry free list", blk);
300 goto out_buf;
301 }
302 }
303 le16_add_cpu(&dh->dqdh_entries, 1);
304 /* Find free structure in block */
305 ddquot = buf + sizeof(struct qt_disk_dqdbheader);
306 for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
307 if (qtree_entry_unused(info, ddquot))
308 break;
309 ddquot += info->dqi_entry_size;
310 }
311 #ifdef __QUOTA_QT_PARANOIA
312 if (i == qtree_dqstr_in_blk(info)) {
313 quota_error(dquot->dq_sb, "Data block full but it shouldn't");
314 *err = -EIO;
315 goto out_buf;
316 }
317 #endif
318 *err = write_blk(info, blk, buf);
319 if (*err < 0) {
320 quota_error(dquot->dq_sb, "Can't write quota data block %u",
321 blk);
322 goto out_buf;
323 }
324 dquot->dq_off = ((loff_t)blk << info->dqi_blocksize_bits) +
325 sizeof(struct qt_disk_dqdbheader) +
326 i * info->dqi_entry_size;
327 kfree(buf);
328 return blk;
329 out_buf:
330 kfree(buf);
331 return 0;
332 }
333
334 /* Insert reference to structure into the trie */
335 static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
336 uint *blks, int depth)
337 {
338 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
339 int ret = 0, newson = 0, newact = 0;
340 __le32 *ref;
341 uint newblk;
342 int i;
343
344 if (!buf)
345 return -ENOMEM;
346 if (!blks[depth]) {
347 ret = get_free_dqblk(info);
348 if (ret < 0)
349 goto out_buf;
350 for (i = 0; i < depth; i++)
351 if (ret == blks[i]) {
352 quota_error(dquot->dq_sb,
353 "Free block already used in tree: block %u",
354 ret);
355 ret = -EIO;
356 goto out_buf;
357 }
358 blks[depth] = ret;
359 memset(buf, 0, info->dqi_usable_bs);
360 newact = 1;
361 } else {
362 ret = read_blk(info, blks[depth], buf);
363 if (ret < 0) {
364 quota_error(dquot->dq_sb, "Can't read tree quota "
365 "block %u", blks[depth]);
366 goto out_buf;
367 }
368 }
369 ref = (__le32 *)buf;
370 newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
371 ret = do_check_range(dquot->dq_sb, "block", newblk, 0,
372 info->dqi_blocks - 1);
373 if (ret)
374 goto out_buf;
375 if (!newblk) {
376 newson = 1;
377 } else {
378 for (i = 0; i <= depth; i++)
379 if (newblk == blks[i]) {
380 quota_error(dquot->dq_sb,
381 "Cycle in quota tree detected: block %u index %u",
382 blks[depth],
383 get_index(info, dquot->dq_id, depth));
384 ret = -EIO;
385 goto out_buf;
386 }
387 }
388 blks[depth + 1] = newblk;
389 if (depth == info->dqi_qtree_depth - 1) {
390 #ifdef __QUOTA_QT_PARANOIA
391 if (newblk) {
392 quota_error(dquot->dq_sb, "Inserting already present "
393 "quota entry (block %u)",
394 le32_to_cpu(ref[get_index(info,
395 dquot->dq_id, depth)]));
396 ret = -EIO;
397 goto out_buf;
398 }
399 #endif
400 blks[depth + 1] = find_free_dqentry(info, dquot, &ret);
401 } else {
402 ret = do_insert_tree(info, dquot, blks, depth + 1);
403 }
404 if (newson && ret >= 0) {
405 ref[get_index(info, dquot->dq_id, depth)] =
406 cpu_to_le32(blks[depth + 1]);
407 ret = write_blk(info, blks[depth], buf);
408 } else if (newact && ret < 0) {
409 put_free_dqblk(info, buf, blks[depth]);
410 }
411 out_buf:
412 kfree(buf);
413 return ret;
414 }
415
416 /* Wrapper for inserting quota structure into tree */
417 static inline int dq_insert_tree(struct qtree_mem_dqinfo *info,
418 struct dquot *dquot)
419 {
420 uint blks[MAX_QTREE_DEPTH] = { QT_TREEOFF };
421
422 #ifdef __QUOTA_QT_PARANOIA
423 if (info->dqi_blocks <= QT_TREEOFF) {
424 quota_error(dquot->dq_sb, "Quota tree root isn't allocated!");
425 return -EIO;
426 }
427 #endif
428 if (info->dqi_qtree_depth >= MAX_QTREE_DEPTH) {
429 quota_error(dquot->dq_sb, "Quota tree depth too big!");
430 return -EIO;
431 }
432 return do_insert_tree(info, dquot, blks, 0);
433 }
434
435 /*
436 * We don't have to be afraid of deadlocks as we never have quotas on quota
437 * files...
438 */
439 int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
440 {
441 int type = dquot->dq_id.type;
442 struct super_block *sb = dquot->dq_sb;
443 ssize_t ret;
444 char *ddquot = kmalloc(info->dqi_entry_size, GFP_KERNEL);
445
446 if (!ddquot)
447 return -ENOMEM;
448
449 /* dq_off is guarded by dqio_sem */
450 if (!dquot->dq_off) {
451 ret = dq_insert_tree(info, dquot);
452 if (ret < 0) {
453 quota_error(sb, "Error %zd occurred while creating "
454 "quota", ret);
455 kfree(ddquot);
456 return ret;
457 }
458 }
459 spin_lock(&dquot->dq_dqb_lock);
460 info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
461 spin_unlock(&dquot->dq_dqb_lock);
462 ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
463 dquot->dq_off);
464 if (ret != info->dqi_entry_size) {
465 quota_error(sb, "dquota write failed");
466 if (ret >= 0)
467 ret = -ENOSPC;
468 } else {
469 ret = 0;
470 }
471 dqstats_inc(DQST_WRITES);
472 kfree(ddquot);
473
474 return ret;
475 }
476 EXPORT_SYMBOL(qtree_write_dquot);
477
478 /* Free dquot entry in data block */
479 static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
480 uint blk)
481 {
482 struct qt_disk_dqdbheader *dh;
483 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
484 int ret = 0;
485
486 if (!buf)
487 return -ENOMEM;
488 if (dquot->dq_off >> info->dqi_blocksize_bits != blk) {
489 quota_error(dquot->dq_sb, "Quota structure has offset to "
490 "other block (%u) than it should (%u)", blk,
491 (uint)(dquot->dq_off >> info->dqi_blocksize_bits));
492 ret = -EIO;
493 goto out_buf;
494 }
495 ret = read_blk(info, blk, buf);
496 if (ret < 0) {
497 quota_error(dquot->dq_sb, "Can't read quota data block %u",
498 blk);
499 goto out_buf;
500 }
501 dh = (struct qt_disk_dqdbheader *)buf;
502 ret = check_dquot_block_header(info, dh);
503 if (ret)
504 goto out_buf;
505 le16_add_cpu(&dh->dqdh_entries, -1);
506 if (!le16_to_cpu(dh->dqdh_entries)) { /* Block got free? */
507 ret = remove_free_dqentry(info, buf, blk);
508 if (ret >= 0)
509 ret = put_free_dqblk(info, buf, blk);
510 if (ret < 0) {
511 quota_error(dquot->dq_sb, "Can't move quota data block "
512 "(%u) to free list", blk);
513 goto out_buf;
514 }
515 } else {
516 memset(buf +
517 (dquot->dq_off & ((1 << info->dqi_blocksize_bits) - 1)),
518 0, info->dqi_entry_size);
519 if (le16_to_cpu(dh->dqdh_entries) ==
520 qtree_dqstr_in_blk(info) - 1) {
521 /* Insert will write block itself */
522 ret = insert_free_dqentry(info, buf, blk);
523 if (ret < 0) {
524 quota_error(dquot->dq_sb, "Can't insert quota "
525 "data block (%u) to free entry list", blk);
526 goto out_buf;
527 }
528 } else {
529 ret = write_blk(info, blk, buf);
530 if (ret < 0) {
531 quota_error(dquot->dq_sb, "Can't write quota "
532 "data block %u", blk);
533 goto out_buf;
534 }
535 }
536 }
537 dquot->dq_off = 0; /* Quota is now unattached */
538 out_buf:
539 kfree(buf);
540 return ret;
541 }
542
543 /* Remove reference to dquot from tree */
544 static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
545 uint *blks, int depth)
546 {
547 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
548 int ret = 0;
549 uint newblk;
550 __le32 *ref = (__le32 *)buf;
551 int i;
552
553 if (!buf)
554 return -ENOMEM;
555 ret = read_blk(info, blks[depth], buf);
556 if (ret < 0) {
557 quota_error(dquot->dq_sb, "Can't read quota data block %u",
558 blks[depth]);
559 goto out_buf;
560 }
561 newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
562 ret = do_check_range(dquot->dq_sb, "block", newblk, QT_TREEOFF,
563 info->dqi_blocks - 1);
564 if (ret)
565 goto out_buf;
566
567 for (i = 0; i <= depth; i++)
568 if (newblk == blks[i]) {
569 quota_error(dquot->dq_sb,
570 "Cycle in quota tree detected: block %u index %u",
571 blks[depth],
572 get_index(info, dquot->dq_id, depth));
573 ret = -EIO;
574 goto out_buf;
575 }
576 if (depth == info->dqi_qtree_depth - 1) {
577 ret = free_dqentry(info, dquot, newblk);
578 blks[depth + 1] = 0;
579 } else {
580 blks[depth + 1] = newblk;
581 ret = remove_tree(info, dquot, blks, depth + 1);
582 }
583 if (ret >= 0 && !blks[depth + 1]) {
584 ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(0);
585 /* Block got empty? */
586 for (i = 0; i < (info->dqi_usable_bs >> 2) && !ref[i]; i++)
587 ;
588 /* Don't put the root block into the free block list */
589 if (i == (info->dqi_usable_bs >> 2)
590 && blks[depth] != QT_TREEOFF) {
591 put_free_dqblk(info, buf, blks[depth]);
592 blks[depth] = 0;
593 } else {
594 ret = write_blk(info, blks[depth], buf);
595 if (ret < 0)
596 quota_error(dquot->dq_sb,
597 "Can't write quota tree block %u",
598 blks[depth]);
599 }
600 }
601 out_buf:
602 kfree(buf);
603 return ret;
604 }
605
606 /* Delete dquot from tree */
607 int qtree_delete_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
608 {
609 uint blks[MAX_QTREE_DEPTH] = { QT_TREEOFF };
610
611 if (!dquot->dq_off) /* Even not allocated? */
612 return 0;
613 if (info->dqi_qtree_depth >= MAX_QTREE_DEPTH) {
614 quota_error(dquot->dq_sb, "Quota tree depth too big!");
615 return -EIO;
616 }
617 return remove_tree(info, dquot, blks, 0);
618 }
619 EXPORT_SYMBOL(qtree_delete_dquot);
620
621 /* Find entry in block */
622 static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
623 struct dquot *dquot, uint blk)
624 {
625 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
626 loff_t ret = 0;
627 int i;
628 char *ddquot;
629
630 if (!buf)
631 return -ENOMEM;
632 ret = read_blk(info, blk, buf);
633 if (ret < 0) {
634 quota_error(dquot->dq_sb, "Can't read quota tree "
635 "block %u", blk);
636 goto out_buf;
637 }
638 ddquot = buf + sizeof(struct qt_disk_dqdbheader);
639 for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
640 if (info->dqi_ops->is_id(ddquot, dquot))
641 break;
642 ddquot += info->dqi_entry_size;
643 }
644 if (i == qtree_dqstr_in_blk(info)) {
645 quota_error(dquot->dq_sb,
646 "Quota for id %u referenced but not present",
647 from_kqid(&init_user_ns, dquot->dq_id));
648 ret = -EIO;
649 goto out_buf;
650 } else {
651 ret = ((loff_t)blk << info->dqi_blocksize_bits) + sizeof(struct
652 qt_disk_dqdbheader) + i * info->dqi_entry_size;
653 }
654 out_buf:
655 kfree(buf);
656 return ret;
657 }
658
659 /* Find entry for given id in the tree */
660 static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
661 struct dquot *dquot, uint *blks, int depth)
662 {
663 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
664 loff_t ret = 0;
665 __le32 *ref = (__le32 *)buf;
666 uint blk;
667 int i;
668
669 if (!buf)
670 return -ENOMEM;
671 ret = read_blk(info, blks[depth], buf);
672 if (ret < 0) {
673 quota_error(dquot->dq_sb, "Can't read quota tree block %u",
674 blks[depth]);
675 goto out_buf;
676 }
677 ret = 0;
678 blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
679 if (!blk) /* No reference? */
680 goto out_buf;
681 ret = do_check_range(dquot->dq_sb, "block", blk, QT_TREEOFF,
682 info->dqi_blocks - 1);
683 if (ret)
684 goto out_buf;
685
686 /* Check for cycles in the tree */
687 for (i = 0; i <= depth; i++)
688 if (blk == blks[i]) {
689 quota_error(dquot->dq_sb,
690 "Cycle in quota tree detected: block %u index %u",
691 blks[depth],
692 get_index(info, dquot->dq_id, depth));
693 ret = -EIO;
694 goto out_buf;
695 }
696 blks[depth + 1] = blk;
697 if (depth < info->dqi_qtree_depth - 1)
698 ret = find_tree_dqentry(info, dquot, blks, depth + 1);
699 else
700 ret = find_block_dqentry(info, dquot, blk);
701 out_buf:
702 kfree(buf);
703 return ret;
704 }
705
706 /* Find entry for given id in the tree - wrapper function */
707 static inline loff_t find_dqentry(struct qtree_mem_dqinfo *info,
708 struct dquot *dquot)
709 {
710 uint blks[MAX_QTREE_DEPTH] = { QT_TREEOFF };
711
712 if (info->dqi_qtree_depth >= MAX_QTREE_DEPTH) {
713 quota_error(dquot->dq_sb, "Quota tree depth too big!");
714 return -EIO;
715 }
716 return find_tree_dqentry(info, dquot, blks, 0);
717 }
718
719 int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
720 {
721 int type = dquot->dq_id.type;
722 struct super_block *sb = dquot->dq_sb;
723 loff_t offset;
724 char *ddquot;
725 int ret = 0;
726
727 #ifdef __QUOTA_QT_PARANOIA
728 /* Invalidated quota? */
729 if (!sb_dqopt(dquot->dq_sb)->files[type]) {
730 quota_error(sb, "Quota invalidated while reading!");
731 return -EIO;
732 }
733 #endif
734 /* Do we know offset of the dquot entry in the quota file? */
735 if (!dquot->dq_off) {
736 offset = find_dqentry(info, dquot);
737 if (offset <= 0) { /* Entry not present? */
738 if (offset < 0)
739 quota_error(sb,"Can't read quota structure "
740 "for id %u",
741 from_kqid(&init_user_ns,
742 dquot->dq_id));
743 dquot->dq_off = 0;
744 set_bit(DQ_FAKE_B, &dquot->dq_flags);
745 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
746 ret = offset;
747 goto out;
748 }
749 dquot->dq_off = offset;
750 }
751 ddquot = kmalloc(info->dqi_entry_size, GFP_KERNEL);
752 if (!ddquot)
753 return -ENOMEM;
754 ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size,
755 dquot->dq_off);
756 if (ret != info->dqi_entry_size) {
757 if (ret >= 0)
758 ret = -EIO;
759 quota_error(sb, "Error while reading quota structure for id %u",
760 from_kqid(&init_user_ns, dquot->dq_id));
761 set_bit(DQ_FAKE_B, &dquot->dq_flags);
762 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
763 kfree(ddquot);
764 goto out;
765 }
766 spin_lock(&dquot->dq_dqb_lock);
767 info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
768 if (!dquot->dq_dqb.dqb_bhardlimit &&
769 !dquot->dq_dqb.dqb_bsoftlimit &&
770 !dquot->dq_dqb.dqb_ihardlimit &&
771 !dquot->dq_dqb.dqb_isoftlimit)
772 set_bit(DQ_FAKE_B, &dquot->dq_flags);
773 spin_unlock(&dquot->dq_dqb_lock);
774 kfree(ddquot);
775 out:
776 dqstats_inc(DQST_READS);
777 return ret;
778 }
779 EXPORT_SYMBOL(qtree_read_dquot);
780
781 /* Check whether dquot should not be deleted. We know we are
782 * the only one operating on dquot (thanks to dq_lock) */
783 int qtree_release_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
784 {
785 if (test_bit(DQ_FAKE_B, &dquot->dq_flags) &&
786 !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
787 return qtree_delete_dquot(info, dquot);
788 return 0;
789 }
790 EXPORT_SYMBOL(qtree_release_dquot);
791
792 static int find_next_id(struct qtree_mem_dqinfo *info, qid_t *id,
793 unsigned int blk, int depth)
794 {
795 char *buf = kmalloc(info->dqi_usable_bs, GFP_KERNEL);
796 __le32 *ref = (__le32 *)buf;
797 ssize_t ret;
798 unsigned int epb = info->dqi_usable_bs >> 2;
799 unsigned int level_inc = 1;
800 int i;
801
802 if (!buf)
803 return -ENOMEM;
804
805 for (i = depth; i < info->dqi_qtree_depth - 1; i++)
806 level_inc *= epb;
807
808 ret = read_blk(info, blk, buf);
809 if (ret < 0) {
810 quota_error(info->dqi_sb,
811 "Can't read quota tree block %u", blk);
812 goto out_buf;
813 }
814 for (i = __get_index(info, *id, depth); i < epb; i++) {
815 uint blk_no = le32_to_cpu(ref[i]);
816
817 if (blk_no == 0) {
818 *id += level_inc;
819 continue;
820 }
821 ret = do_check_range(info->dqi_sb, "block", blk_no, 0,
822 info->dqi_blocks - 1);
823 if (ret)
824 goto out_buf;
825 if (depth == info->dqi_qtree_depth - 1) {
826 ret = 0;
827 goto out_buf;
828 }
829 ret = find_next_id(info, id, blk_no, depth + 1);
830 if (ret != -ENOENT)
831 break;
832 }
833 if (i == epb) {
834 ret = -ENOENT;
835 goto out_buf;
836 }
837 out_buf:
838 kfree(buf);
839 return ret;
840 }
841
842 int qtree_get_next_id(struct qtree_mem_dqinfo *info, struct kqid *qid)
843 {
844 qid_t id = from_kqid(&init_user_ns, *qid);
845 int ret;
846
847 ret = find_next_id(info, &id, QT_TREEOFF, 0);
848 if (ret < 0)
849 return ret;
850 *qid = make_kqid(&init_user_ns, qid->type, id);
851 return 0;
852 }
853 EXPORT_SYMBOL(qtree_get_next_id);
854
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