xref: /openbmc/linux/fs/quota/quota_tree.c (revision b34e08d5)
1 /*
2  *	vfsv0 quota IO operations on file
3  */
4 
5 #include <linux/errno.h>
6 #include <linux/fs.h>
7 #include <linux/mount.h>
8 #include <linux/dqblk_v2.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/quotaops.h>
14 
15 #include <asm/byteorder.h>
16 
17 #include "quota_tree.h"
18 
19 MODULE_AUTHOR("Jan Kara");
20 MODULE_DESCRIPTION("Quota trie support");
21 MODULE_LICENSE("GPL");
22 
23 #define __QUOTA_QT_PARANOIA
24 
25 static int get_index(struct qtree_mem_dqinfo *info, struct kqid qid, int depth)
26 {
27 	unsigned int epb = info->dqi_usable_bs >> 2;
28 	qid_t id = from_kqid(&init_user_ns, qid);
29 
30 	depth = info->dqi_qtree_depth - depth - 1;
31 	while (depth--)
32 		id /= epb;
33 	return id % epb;
34 }
35 
36 /* Number of entries in one blocks */
37 static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info)
38 {
39 	return (info->dqi_usable_bs - sizeof(struct qt_disk_dqdbheader))
40 	       / info->dqi_entry_size;
41 }
42 
43 static char *getdqbuf(size_t size)
44 {
45 	char *buf = kmalloc(size, GFP_NOFS);
46 	if (!buf)
47 		printk(KERN_WARNING
48 		       "VFS: Not enough memory for quota buffers.\n");
49 	return buf;
50 }
51 
52 static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
53 {
54 	struct super_block *sb = info->dqi_sb;
55 
56 	memset(buf, 0, info->dqi_usable_bs);
57 	return sb->s_op->quota_read(sb, info->dqi_type, buf,
58 	       info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
59 }
60 
61 static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
62 {
63 	struct super_block *sb = info->dqi_sb;
64 	ssize_t ret;
65 
66 	ret = sb->s_op->quota_write(sb, info->dqi_type, buf,
67 	       info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
68 	if (ret != info->dqi_usable_bs) {
69 		quota_error(sb, "dquota write failed");
70 		if (ret >= 0)
71 			ret = -EIO;
72 	}
73 	return ret;
74 }
75 
76 /* Remove empty block from list and return it */
77 static int get_free_dqblk(struct qtree_mem_dqinfo *info)
78 {
79 	char *buf = getdqbuf(info->dqi_usable_bs);
80 	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
81 	int ret, blk;
82 
83 	if (!buf)
84 		return -ENOMEM;
85 	if (info->dqi_free_blk) {
86 		blk = info->dqi_free_blk;
87 		ret = read_blk(info, blk, buf);
88 		if (ret < 0)
89 			goto out_buf;
90 		info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
91 	}
92 	else {
93 		memset(buf, 0, info->dqi_usable_bs);
94 		/* Assure block allocation... */
95 		ret = write_blk(info, info->dqi_blocks, buf);
96 		if (ret < 0)
97 			goto out_buf;
98 		blk = info->dqi_blocks++;
99 	}
100 	mark_info_dirty(info->dqi_sb, info->dqi_type);
101 	ret = blk;
102 out_buf:
103 	kfree(buf);
104 	return ret;
105 }
106 
107 /* Insert empty block to the list */
108 static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk)
109 {
110 	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
111 	int err;
112 
113 	dh->dqdh_next_free = cpu_to_le32(info->dqi_free_blk);
114 	dh->dqdh_prev_free = cpu_to_le32(0);
115 	dh->dqdh_entries = cpu_to_le16(0);
116 	err = write_blk(info, blk, buf);
117 	if (err < 0)
118 		return err;
119 	info->dqi_free_blk = blk;
120 	mark_info_dirty(info->dqi_sb, info->dqi_type);
121 	return 0;
122 }
123 
124 /* Remove given block from the list of blocks with free entries */
125 static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
126 			       uint blk)
127 {
128 	char *tmpbuf = getdqbuf(info->dqi_usable_bs);
129 	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
130 	uint nextblk = le32_to_cpu(dh->dqdh_next_free);
131 	uint prevblk = le32_to_cpu(dh->dqdh_prev_free);
132 	int err;
133 
134 	if (!tmpbuf)
135 		return -ENOMEM;
136 	if (nextblk) {
137 		err = read_blk(info, nextblk, tmpbuf);
138 		if (err < 0)
139 			goto out_buf;
140 		((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
141 							dh->dqdh_prev_free;
142 		err = write_blk(info, nextblk, tmpbuf);
143 		if (err < 0)
144 			goto out_buf;
145 	}
146 	if (prevblk) {
147 		err = read_blk(info, prevblk, tmpbuf);
148 		if (err < 0)
149 			goto out_buf;
150 		((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free =
151 							dh->dqdh_next_free;
152 		err = write_blk(info, prevblk, tmpbuf);
153 		if (err < 0)
154 			goto out_buf;
155 	} else {
156 		info->dqi_free_entry = nextblk;
157 		mark_info_dirty(info->dqi_sb, info->dqi_type);
158 	}
159 	kfree(tmpbuf);
160 	dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
161 	/* No matter whether write succeeds block is out of list */
162 	if (write_blk(info, blk, buf) < 0)
163 		quota_error(info->dqi_sb, "Can't write block (%u) "
164 			    "with free entries", blk);
165 	return 0;
166 out_buf:
167 	kfree(tmpbuf);
168 	return err;
169 }
170 
171 /* Insert given block to the beginning of list with free entries */
172 static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
173 			       uint blk)
174 {
175 	char *tmpbuf = getdqbuf(info->dqi_usable_bs);
176 	struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
177 	int err;
178 
179 	if (!tmpbuf)
180 		return -ENOMEM;
181 	dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry);
182 	dh->dqdh_prev_free = cpu_to_le32(0);
183 	err = write_blk(info, blk, buf);
184 	if (err < 0)
185 		goto out_buf;
186 	if (info->dqi_free_entry) {
187 		err = read_blk(info, info->dqi_free_entry, tmpbuf);
188 		if (err < 0)
189 			goto out_buf;
190 		((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
191 							cpu_to_le32(blk);
192 		err = write_blk(info, info->dqi_free_entry, tmpbuf);
193 		if (err < 0)
194 			goto out_buf;
195 	}
196 	kfree(tmpbuf);
197 	info->dqi_free_entry = blk;
198 	mark_info_dirty(info->dqi_sb, info->dqi_type);
199 	return 0;
200 out_buf:
201 	kfree(tmpbuf);
202 	return err;
203 }
204 
205 /* Is the entry in the block free? */
206 int qtree_entry_unused(struct qtree_mem_dqinfo *info, char *disk)
207 {
208 	int i;
209 
210 	for (i = 0; i < info->dqi_entry_size; i++)
211 		if (disk[i])
212 			return 0;
213 	return 1;
214 }
215 EXPORT_SYMBOL(qtree_entry_unused);
216 
217 /* Find space for dquot */
218 static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
219 			      struct dquot *dquot, int *err)
220 {
221 	uint blk, i;
222 	struct qt_disk_dqdbheader *dh;
223 	char *buf = getdqbuf(info->dqi_usable_bs);
224 	char *ddquot;
225 
226 	*err = 0;
227 	if (!buf) {
228 		*err = -ENOMEM;
229 		return 0;
230 	}
231 	dh = (struct qt_disk_dqdbheader *)buf;
232 	if (info->dqi_free_entry) {
233 		blk = info->dqi_free_entry;
234 		*err = read_blk(info, blk, buf);
235 		if (*err < 0)
236 			goto out_buf;
237 	} else {
238 		blk = get_free_dqblk(info);
239 		if ((int)blk < 0) {
240 			*err = blk;
241 			kfree(buf);
242 			return 0;
243 		}
244 		memset(buf, 0, info->dqi_usable_bs);
245 		/* This is enough as the block is already zeroed and the entry
246 		 * list is empty... */
247 		info->dqi_free_entry = blk;
248 		mark_info_dirty(dquot->dq_sb, dquot->dq_id.type);
249 	}
250 	/* Block will be full? */
251 	if (le16_to_cpu(dh->dqdh_entries) + 1 >= qtree_dqstr_in_blk(info)) {
252 		*err = remove_free_dqentry(info, buf, blk);
253 		if (*err < 0) {
254 			quota_error(dquot->dq_sb, "Can't remove block (%u) "
255 				    "from entry free list", blk);
256 			goto out_buf;
257 		}
258 	}
259 	le16_add_cpu(&dh->dqdh_entries, 1);
260 	/* Find free structure in block */
261 	ddquot = buf + sizeof(struct qt_disk_dqdbheader);
262 	for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
263 		if (qtree_entry_unused(info, ddquot))
264 			break;
265 		ddquot += info->dqi_entry_size;
266 	}
267 #ifdef __QUOTA_QT_PARANOIA
268 	if (i == qtree_dqstr_in_blk(info)) {
269 		quota_error(dquot->dq_sb, "Data block full but it shouldn't");
270 		*err = -EIO;
271 		goto out_buf;
272 	}
273 #endif
274 	*err = write_blk(info, blk, buf);
275 	if (*err < 0) {
276 		quota_error(dquot->dq_sb, "Can't write quota data block %u",
277 			    blk);
278 		goto out_buf;
279 	}
280 	dquot->dq_off = (blk << info->dqi_blocksize_bits) +
281 			sizeof(struct qt_disk_dqdbheader) +
282 			i * info->dqi_entry_size;
283 	kfree(buf);
284 	return blk;
285 out_buf:
286 	kfree(buf);
287 	return 0;
288 }
289 
290 /* Insert reference to structure into the trie */
291 static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
292 			  uint *treeblk, int depth)
293 {
294 	char *buf = getdqbuf(info->dqi_usable_bs);
295 	int ret = 0, newson = 0, newact = 0;
296 	__le32 *ref;
297 	uint newblk;
298 
299 	if (!buf)
300 		return -ENOMEM;
301 	if (!*treeblk) {
302 		ret = get_free_dqblk(info);
303 		if (ret < 0)
304 			goto out_buf;
305 		*treeblk = ret;
306 		memset(buf, 0, info->dqi_usable_bs);
307 		newact = 1;
308 	} else {
309 		ret = read_blk(info, *treeblk, buf);
310 		if (ret < 0) {
311 			quota_error(dquot->dq_sb, "Can't read tree quota "
312 				    "block %u", *treeblk);
313 			goto out_buf;
314 		}
315 	}
316 	ref = (__le32 *)buf;
317 	newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
318 	if (!newblk)
319 		newson = 1;
320 	if (depth == info->dqi_qtree_depth - 1) {
321 #ifdef __QUOTA_QT_PARANOIA
322 		if (newblk) {
323 			quota_error(dquot->dq_sb, "Inserting already present "
324 				    "quota entry (block %u)",
325 				    le32_to_cpu(ref[get_index(info,
326 						dquot->dq_id, depth)]));
327 			ret = -EIO;
328 			goto out_buf;
329 		}
330 #endif
331 		newblk = find_free_dqentry(info, dquot, &ret);
332 	} else {
333 		ret = do_insert_tree(info, dquot, &newblk, depth+1);
334 	}
335 	if (newson && ret >= 0) {
336 		ref[get_index(info, dquot->dq_id, depth)] =
337 							cpu_to_le32(newblk);
338 		ret = write_blk(info, *treeblk, buf);
339 	} else if (newact && ret < 0) {
340 		put_free_dqblk(info, buf, *treeblk);
341 	}
342 out_buf:
343 	kfree(buf);
344 	return ret;
345 }
346 
347 /* Wrapper for inserting quota structure into tree */
348 static inline int dq_insert_tree(struct qtree_mem_dqinfo *info,
349 				 struct dquot *dquot)
350 {
351 	int tmp = QT_TREEOFF;
352 	return do_insert_tree(info, dquot, &tmp, 0);
353 }
354 
355 /*
356  * We don't have to be afraid of deadlocks as we never have quotas on quota
357  * files...
358  */
359 int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
360 {
361 	int type = dquot->dq_id.type;
362 	struct super_block *sb = dquot->dq_sb;
363 	ssize_t ret;
364 	char *ddquot = getdqbuf(info->dqi_entry_size);
365 
366 	if (!ddquot)
367 		return -ENOMEM;
368 
369 	/* dq_off is guarded by dqio_mutex */
370 	if (!dquot->dq_off) {
371 		ret = dq_insert_tree(info, dquot);
372 		if (ret < 0) {
373 			quota_error(sb, "Error %zd occurred while creating "
374 				    "quota", ret);
375 			kfree(ddquot);
376 			return ret;
377 		}
378 	}
379 	spin_lock(&dq_data_lock);
380 	info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
381 	spin_unlock(&dq_data_lock);
382 	ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
383 				    dquot->dq_off);
384 	if (ret != info->dqi_entry_size) {
385 		quota_error(sb, "dquota write failed");
386 		if (ret >= 0)
387 			ret = -ENOSPC;
388 	} else {
389 		ret = 0;
390 	}
391 	dqstats_inc(DQST_WRITES);
392 	kfree(ddquot);
393 
394 	return ret;
395 }
396 EXPORT_SYMBOL(qtree_write_dquot);
397 
398 /* Free dquot entry in data block */
399 static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
400 			uint blk)
401 {
402 	struct qt_disk_dqdbheader *dh;
403 	char *buf = getdqbuf(info->dqi_usable_bs);
404 	int ret = 0;
405 
406 	if (!buf)
407 		return -ENOMEM;
408 	if (dquot->dq_off >> info->dqi_blocksize_bits != blk) {
409 		quota_error(dquot->dq_sb, "Quota structure has offset to "
410 			"other block (%u) than it should (%u)", blk,
411 			(uint)(dquot->dq_off >> info->dqi_blocksize_bits));
412 		goto out_buf;
413 	}
414 	ret = read_blk(info, blk, buf);
415 	if (ret < 0) {
416 		quota_error(dquot->dq_sb, "Can't read quota data block %u",
417 			    blk);
418 		goto out_buf;
419 	}
420 	dh = (struct qt_disk_dqdbheader *)buf;
421 	le16_add_cpu(&dh->dqdh_entries, -1);
422 	if (!le16_to_cpu(dh->dqdh_entries)) {	/* Block got free? */
423 		ret = remove_free_dqentry(info, buf, blk);
424 		if (ret >= 0)
425 			ret = put_free_dqblk(info, buf, blk);
426 		if (ret < 0) {
427 			quota_error(dquot->dq_sb, "Can't move quota data block "
428 				    "(%u) to free list", blk);
429 			goto out_buf;
430 		}
431 	} else {
432 		memset(buf +
433 		       (dquot->dq_off & ((1 << info->dqi_blocksize_bits) - 1)),
434 		       0, info->dqi_entry_size);
435 		if (le16_to_cpu(dh->dqdh_entries) ==
436 		    qtree_dqstr_in_blk(info) - 1) {
437 			/* Insert will write block itself */
438 			ret = insert_free_dqentry(info, buf, blk);
439 			if (ret < 0) {
440 				quota_error(dquot->dq_sb, "Can't insert quota "
441 				    "data block (%u) to free entry list", blk);
442 				goto out_buf;
443 			}
444 		} else {
445 			ret = write_blk(info, blk, buf);
446 			if (ret < 0) {
447 				quota_error(dquot->dq_sb, "Can't write quota "
448 					    "data block %u", blk);
449 				goto out_buf;
450 			}
451 		}
452 	}
453 	dquot->dq_off = 0;	/* Quota is now unattached */
454 out_buf:
455 	kfree(buf);
456 	return ret;
457 }
458 
459 /* Remove reference to dquot from tree */
460 static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
461 		       uint *blk, int depth)
462 {
463 	char *buf = getdqbuf(info->dqi_usable_bs);
464 	int ret = 0;
465 	uint newblk;
466 	__le32 *ref = (__le32 *)buf;
467 
468 	if (!buf)
469 		return -ENOMEM;
470 	ret = read_blk(info, *blk, buf);
471 	if (ret < 0) {
472 		quota_error(dquot->dq_sb, "Can't read quota data block %u",
473 			    *blk);
474 		goto out_buf;
475 	}
476 	newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
477 	if (depth == info->dqi_qtree_depth - 1) {
478 		ret = free_dqentry(info, dquot, newblk);
479 		newblk = 0;
480 	} else {
481 		ret = remove_tree(info, dquot, &newblk, depth+1);
482 	}
483 	if (ret >= 0 && !newblk) {
484 		int i;
485 		ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(0);
486 		/* Block got empty? */
487 		for (i = 0; i < (info->dqi_usable_bs >> 2) && !ref[i]; i++)
488 			;
489 		/* Don't put the root block into the free block list */
490 		if (i == (info->dqi_usable_bs >> 2)
491 		    && *blk != QT_TREEOFF) {
492 			put_free_dqblk(info, buf, *blk);
493 			*blk = 0;
494 		} else {
495 			ret = write_blk(info, *blk, buf);
496 			if (ret < 0)
497 				quota_error(dquot->dq_sb,
498 					    "Can't write quota tree block %u",
499 					    *blk);
500 		}
501 	}
502 out_buf:
503 	kfree(buf);
504 	return ret;
505 }
506 
507 /* Delete dquot from tree */
508 int qtree_delete_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
509 {
510 	uint tmp = QT_TREEOFF;
511 
512 	if (!dquot->dq_off)	/* Even not allocated? */
513 		return 0;
514 	return remove_tree(info, dquot, &tmp, 0);
515 }
516 EXPORT_SYMBOL(qtree_delete_dquot);
517 
518 /* Find entry in block */
519 static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
520 				 struct dquot *dquot, uint blk)
521 {
522 	char *buf = getdqbuf(info->dqi_usable_bs);
523 	loff_t ret = 0;
524 	int i;
525 	char *ddquot;
526 
527 	if (!buf)
528 		return -ENOMEM;
529 	ret = read_blk(info, blk, buf);
530 	if (ret < 0) {
531 		quota_error(dquot->dq_sb, "Can't read quota tree "
532 			    "block %u", blk);
533 		goto out_buf;
534 	}
535 	ddquot = buf + sizeof(struct qt_disk_dqdbheader);
536 	for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
537 		if (info->dqi_ops->is_id(ddquot, dquot))
538 			break;
539 		ddquot += info->dqi_entry_size;
540 	}
541 	if (i == qtree_dqstr_in_blk(info)) {
542 		quota_error(dquot->dq_sb,
543 			    "Quota for id %u referenced but not present",
544 			    from_kqid(&init_user_ns, dquot->dq_id));
545 		ret = -EIO;
546 		goto out_buf;
547 	} else {
548 		ret = (blk << info->dqi_blocksize_bits) + sizeof(struct
549 		  qt_disk_dqdbheader) + i * info->dqi_entry_size;
550 	}
551 out_buf:
552 	kfree(buf);
553 	return ret;
554 }
555 
556 /* Find entry for given id in the tree */
557 static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
558 				struct dquot *dquot, uint blk, int depth)
559 {
560 	char *buf = getdqbuf(info->dqi_usable_bs);
561 	loff_t ret = 0;
562 	__le32 *ref = (__le32 *)buf;
563 
564 	if (!buf)
565 		return -ENOMEM;
566 	ret = read_blk(info, blk, buf);
567 	if (ret < 0) {
568 		quota_error(dquot->dq_sb, "Can't read quota tree block %u",
569 			    blk);
570 		goto out_buf;
571 	}
572 	ret = 0;
573 	blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
574 	if (!blk)	/* No reference? */
575 		goto out_buf;
576 	if (depth < info->dqi_qtree_depth - 1)
577 		ret = find_tree_dqentry(info, dquot, blk, depth+1);
578 	else
579 		ret = find_block_dqentry(info, dquot, blk);
580 out_buf:
581 	kfree(buf);
582 	return ret;
583 }
584 
585 /* Find entry for given id in the tree - wrapper function */
586 static inline loff_t find_dqentry(struct qtree_mem_dqinfo *info,
587 				  struct dquot *dquot)
588 {
589 	return find_tree_dqentry(info, dquot, QT_TREEOFF, 0);
590 }
591 
592 int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
593 {
594 	int type = dquot->dq_id.type;
595 	struct super_block *sb = dquot->dq_sb;
596 	loff_t offset;
597 	char *ddquot;
598 	int ret = 0;
599 
600 #ifdef __QUOTA_QT_PARANOIA
601 	/* Invalidated quota? */
602 	if (!sb_dqopt(dquot->dq_sb)->files[type]) {
603 		quota_error(sb, "Quota invalidated while reading!");
604 		return -EIO;
605 	}
606 #endif
607 	/* Do we know offset of the dquot entry in the quota file? */
608 	if (!dquot->dq_off) {
609 		offset = find_dqentry(info, dquot);
610 		if (offset <= 0) {	/* Entry not present? */
611 			if (offset < 0)
612 				quota_error(sb,"Can't read quota structure "
613 					    "for id %u",
614 					    from_kqid(&init_user_ns,
615 						      dquot->dq_id));
616 			dquot->dq_off = 0;
617 			set_bit(DQ_FAKE_B, &dquot->dq_flags);
618 			memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
619 			ret = offset;
620 			goto out;
621 		}
622 		dquot->dq_off = offset;
623 	}
624 	ddquot = getdqbuf(info->dqi_entry_size);
625 	if (!ddquot)
626 		return -ENOMEM;
627 	ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size,
628 				   dquot->dq_off);
629 	if (ret != info->dqi_entry_size) {
630 		if (ret >= 0)
631 			ret = -EIO;
632 		quota_error(sb, "Error while reading quota structure for id %u",
633 			    from_kqid(&init_user_ns, dquot->dq_id));
634 		set_bit(DQ_FAKE_B, &dquot->dq_flags);
635 		memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
636 		kfree(ddquot);
637 		goto out;
638 	}
639 	spin_lock(&dq_data_lock);
640 	info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
641 	if (!dquot->dq_dqb.dqb_bhardlimit &&
642 	    !dquot->dq_dqb.dqb_bsoftlimit &&
643 	    !dquot->dq_dqb.dqb_ihardlimit &&
644 	    !dquot->dq_dqb.dqb_isoftlimit)
645 		set_bit(DQ_FAKE_B, &dquot->dq_flags);
646 	spin_unlock(&dq_data_lock);
647 	kfree(ddquot);
648 out:
649 	dqstats_inc(DQST_READS);
650 	return ret;
651 }
652 EXPORT_SYMBOL(qtree_read_dquot);
653 
654 /* Check whether dquot should not be deleted. We know we are
655  * the only one operating on dquot (thanks to dq_lock) */
656 int qtree_release_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
657 {
658 	if (test_bit(DQ_FAKE_B, &dquot->dq_flags) &&
659 	    !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
660 		return qtree_delete_dquot(info, dquot);
661 	return 0;
662 }
663 EXPORT_SYMBOL(qtree_release_dquot);
664