xref: /linux/fs/xfs/xfs_dquot.c (revision 5ff328836dfde0cef9f28c8b8791a90a36d7a183)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2003 Silicon Graphics, Inc.
4  * All Rights Reserved.
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_format.h"
9 #include "xfs_log_format.h"
10 #include "xfs_shared.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_bit.h"
13 #include "xfs_mount.h"
14 #include "xfs_defer.h"
15 #include "xfs_inode.h"
16 #include "xfs_bmap.h"
17 #include "xfs_bmap_util.h"
18 #include "xfs_alloc.h"
19 #include "xfs_quota.h"
20 #include "xfs_error.h"
21 #include "xfs_trans.h"
22 #include "xfs_buf_item.h"
23 #include "xfs_trans_space.h"
24 #include "xfs_trans_priv.h"
25 #include "xfs_qm.h"
26 #include "xfs_cksum.h"
27 #include "xfs_trace.h"
28 #include "xfs_log.h"
29 #include "xfs_bmap_btree.h"
30 
31 /*
32  * Lock order:
33  *
34  * ip->i_lock
35  *   qi->qi_tree_lock
36  *     dquot->q_qlock (xfs_dqlock() and friends)
37  *       dquot->q_flush (xfs_dqflock() and friends)
38  *       qi->qi_lru_lock
39  *
40  * If two dquots need to be locked the order is user before group/project,
41  * otherwise by the lowest id first, see xfs_dqlock2.
42  */
43 
44 struct kmem_zone		*xfs_qm_dqtrxzone;
45 static struct kmem_zone		*xfs_qm_dqzone;
46 
47 static struct lock_class_key xfs_dquot_group_class;
48 static struct lock_class_key xfs_dquot_project_class;
49 
50 /*
51  * This is called to free all the memory associated with a dquot
52  */
53 void
54 xfs_qm_dqdestroy(
55 	xfs_dquot_t	*dqp)
56 {
57 	ASSERT(list_empty(&dqp->q_lru));
58 
59 	kmem_free(dqp->q_logitem.qli_item.li_lv_shadow);
60 	mutex_destroy(&dqp->q_qlock);
61 
62 	XFS_STATS_DEC(dqp->q_mount, xs_qm_dquot);
63 	kmem_zone_free(xfs_qm_dqzone, dqp);
64 }
65 
66 /*
67  * If default limits are in force, push them into the dquot now.
68  * We overwrite the dquot limits only if they are zero and this
69  * is not the root dquot.
70  */
71 void
72 xfs_qm_adjust_dqlimits(
73 	struct xfs_mount	*mp,
74 	struct xfs_dquot	*dq)
75 {
76 	struct xfs_quotainfo	*q = mp->m_quotainfo;
77 	struct xfs_disk_dquot	*d = &dq->q_core;
78 	struct xfs_def_quota	*defq;
79 	int			prealloc = 0;
80 
81 	ASSERT(d->d_id);
82 	defq = xfs_get_defquota(dq, q);
83 
84 	if (defq->bsoftlimit && !d->d_blk_softlimit) {
85 		d->d_blk_softlimit = cpu_to_be64(defq->bsoftlimit);
86 		prealloc = 1;
87 	}
88 	if (defq->bhardlimit && !d->d_blk_hardlimit) {
89 		d->d_blk_hardlimit = cpu_to_be64(defq->bhardlimit);
90 		prealloc = 1;
91 	}
92 	if (defq->isoftlimit && !d->d_ino_softlimit)
93 		d->d_ino_softlimit = cpu_to_be64(defq->isoftlimit);
94 	if (defq->ihardlimit && !d->d_ino_hardlimit)
95 		d->d_ino_hardlimit = cpu_to_be64(defq->ihardlimit);
96 	if (defq->rtbsoftlimit && !d->d_rtb_softlimit)
97 		d->d_rtb_softlimit = cpu_to_be64(defq->rtbsoftlimit);
98 	if (defq->rtbhardlimit && !d->d_rtb_hardlimit)
99 		d->d_rtb_hardlimit = cpu_to_be64(defq->rtbhardlimit);
100 
101 	if (prealloc)
102 		xfs_dquot_set_prealloc_limits(dq);
103 }
104 
105 /*
106  * Check the limits and timers of a dquot and start or reset timers
107  * if necessary.
108  * This gets called even when quota enforcement is OFF, which makes our
109  * life a little less complicated. (We just don't reject any quota
110  * reservations in that case, when enforcement is off).
111  * We also return 0 as the values of the timers in Q_GETQUOTA calls, when
112  * enforcement's off.
113  * In contrast, warnings are a little different in that they don't
114  * 'automatically' get started when limits get exceeded.  They do
115  * get reset to zero, however, when we find the count to be under
116  * the soft limit (they are only ever set non-zero via userspace).
117  */
118 void
119 xfs_qm_adjust_dqtimers(
120 	xfs_mount_t		*mp,
121 	xfs_disk_dquot_t	*d)
122 {
123 	ASSERT(d->d_id);
124 
125 #ifdef DEBUG
126 	if (d->d_blk_hardlimit)
127 		ASSERT(be64_to_cpu(d->d_blk_softlimit) <=
128 		       be64_to_cpu(d->d_blk_hardlimit));
129 	if (d->d_ino_hardlimit)
130 		ASSERT(be64_to_cpu(d->d_ino_softlimit) <=
131 		       be64_to_cpu(d->d_ino_hardlimit));
132 	if (d->d_rtb_hardlimit)
133 		ASSERT(be64_to_cpu(d->d_rtb_softlimit) <=
134 		       be64_to_cpu(d->d_rtb_hardlimit));
135 #endif
136 
137 	if (!d->d_btimer) {
138 		if ((d->d_blk_softlimit &&
139 		     (be64_to_cpu(d->d_bcount) >
140 		      be64_to_cpu(d->d_blk_softlimit))) ||
141 		    (d->d_blk_hardlimit &&
142 		     (be64_to_cpu(d->d_bcount) >
143 		      be64_to_cpu(d->d_blk_hardlimit)))) {
144 			d->d_btimer = cpu_to_be32(get_seconds() +
145 					mp->m_quotainfo->qi_btimelimit);
146 		} else {
147 			d->d_bwarns = 0;
148 		}
149 	} else {
150 		if ((!d->d_blk_softlimit ||
151 		     (be64_to_cpu(d->d_bcount) <=
152 		      be64_to_cpu(d->d_blk_softlimit))) &&
153 		    (!d->d_blk_hardlimit ||
154 		    (be64_to_cpu(d->d_bcount) <=
155 		     be64_to_cpu(d->d_blk_hardlimit)))) {
156 			d->d_btimer = 0;
157 		}
158 	}
159 
160 	if (!d->d_itimer) {
161 		if ((d->d_ino_softlimit &&
162 		     (be64_to_cpu(d->d_icount) >
163 		      be64_to_cpu(d->d_ino_softlimit))) ||
164 		    (d->d_ino_hardlimit &&
165 		     (be64_to_cpu(d->d_icount) >
166 		      be64_to_cpu(d->d_ino_hardlimit)))) {
167 			d->d_itimer = cpu_to_be32(get_seconds() +
168 					mp->m_quotainfo->qi_itimelimit);
169 		} else {
170 			d->d_iwarns = 0;
171 		}
172 	} else {
173 		if ((!d->d_ino_softlimit ||
174 		     (be64_to_cpu(d->d_icount) <=
175 		      be64_to_cpu(d->d_ino_softlimit)))  &&
176 		    (!d->d_ino_hardlimit ||
177 		     (be64_to_cpu(d->d_icount) <=
178 		      be64_to_cpu(d->d_ino_hardlimit)))) {
179 			d->d_itimer = 0;
180 		}
181 	}
182 
183 	if (!d->d_rtbtimer) {
184 		if ((d->d_rtb_softlimit &&
185 		     (be64_to_cpu(d->d_rtbcount) >
186 		      be64_to_cpu(d->d_rtb_softlimit))) ||
187 		    (d->d_rtb_hardlimit &&
188 		     (be64_to_cpu(d->d_rtbcount) >
189 		      be64_to_cpu(d->d_rtb_hardlimit)))) {
190 			d->d_rtbtimer = cpu_to_be32(get_seconds() +
191 					mp->m_quotainfo->qi_rtbtimelimit);
192 		} else {
193 			d->d_rtbwarns = 0;
194 		}
195 	} else {
196 		if ((!d->d_rtb_softlimit ||
197 		     (be64_to_cpu(d->d_rtbcount) <=
198 		      be64_to_cpu(d->d_rtb_softlimit))) &&
199 		    (!d->d_rtb_hardlimit ||
200 		     (be64_to_cpu(d->d_rtbcount) <=
201 		      be64_to_cpu(d->d_rtb_hardlimit)))) {
202 			d->d_rtbtimer = 0;
203 		}
204 	}
205 }
206 
207 /*
208  * initialize a buffer full of dquots and log the whole thing
209  */
210 STATIC void
211 xfs_qm_init_dquot_blk(
212 	xfs_trans_t	*tp,
213 	xfs_mount_t	*mp,
214 	xfs_dqid_t	id,
215 	uint		type,
216 	xfs_buf_t	*bp)
217 {
218 	struct xfs_quotainfo	*q = mp->m_quotainfo;
219 	xfs_dqblk_t	*d;
220 	xfs_dqid_t	curid;
221 	int		i;
222 
223 	ASSERT(tp);
224 	ASSERT(xfs_buf_islocked(bp));
225 
226 	d = bp->b_addr;
227 
228 	/*
229 	 * ID of the first dquot in the block - id's are zero based.
230 	 */
231 	curid = id - (id % q->qi_dqperchunk);
232 	memset(d, 0, BBTOB(q->qi_dqchunklen));
233 	for (i = 0; i < q->qi_dqperchunk; i++, d++, curid++) {
234 		d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
235 		d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
236 		d->dd_diskdq.d_id = cpu_to_be32(curid);
237 		d->dd_diskdq.d_flags = type;
238 		if (xfs_sb_version_hascrc(&mp->m_sb)) {
239 			uuid_copy(&d->dd_uuid, &mp->m_sb.sb_meta_uuid);
240 			xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),
241 					 XFS_DQUOT_CRC_OFF);
242 		}
243 	}
244 
245 	xfs_trans_dquot_buf(tp, bp,
246 			    (type & XFS_DQ_USER ? XFS_BLF_UDQUOT_BUF :
247 			    ((type & XFS_DQ_PROJ) ? XFS_BLF_PDQUOT_BUF :
248 			     XFS_BLF_GDQUOT_BUF)));
249 	xfs_trans_log_buf(tp, bp, 0, BBTOB(q->qi_dqchunklen) - 1);
250 }
251 
252 /*
253  * Initialize the dynamic speculative preallocation thresholds. The lo/hi
254  * watermarks correspond to the soft and hard limits by default. If a soft limit
255  * is not specified, we use 95% of the hard limit.
256  */
257 void
258 xfs_dquot_set_prealloc_limits(struct xfs_dquot *dqp)
259 {
260 	uint64_t space;
261 
262 	dqp->q_prealloc_hi_wmark = be64_to_cpu(dqp->q_core.d_blk_hardlimit);
263 	dqp->q_prealloc_lo_wmark = be64_to_cpu(dqp->q_core.d_blk_softlimit);
264 	if (!dqp->q_prealloc_lo_wmark) {
265 		dqp->q_prealloc_lo_wmark = dqp->q_prealloc_hi_wmark;
266 		do_div(dqp->q_prealloc_lo_wmark, 100);
267 		dqp->q_prealloc_lo_wmark *= 95;
268 	}
269 
270 	space = dqp->q_prealloc_hi_wmark;
271 
272 	do_div(space, 100);
273 	dqp->q_low_space[XFS_QLOWSP_1_PCNT] = space;
274 	dqp->q_low_space[XFS_QLOWSP_3_PCNT] = space * 3;
275 	dqp->q_low_space[XFS_QLOWSP_5_PCNT] = space * 5;
276 }
277 
278 /*
279  * Ensure that the given in-core dquot has a buffer on disk backing it, and
280  * return the buffer. This is called when the bmapi finds a hole.
281  */
282 STATIC int
283 xfs_dquot_disk_alloc(
284 	struct xfs_trans	**tpp,
285 	struct xfs_dquot	*dqp,
286 	struct xfs_buf		**bpp)
287 {
288 	struct xfs_bmbt_irec	map;
289 	struct xfs_trans	*tp = *tpp;
290 	struct xfs_mount	*mp = tp->t_mountp;
291 	struct xfs_buf		*bp;
292 	struct xfs_inode	*quotip = xfs_quota_inode(mp, dqp->dq_flags);
293 	int			nmaps = 1;
294 	int			error;
295 
296 	trace_xfs_dqalloc(dqp);
297 
298 	xfs_ilock(quotip, XFS_ILOCK_EXCL);
299 	if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
300 		/*
301 		 * Return if this type of quotas is turned off while we didn't
302 		 * have an inode lock
303 		 */
304 		xfs_iunlock(quotip, XFS_ILOCK_EXCL);
305 		return -ESRCH;
306 	}
307 
308 	/* Create the block mapping. */
309 	xfs_trans_ijoin(tp, quotip, XFS_ILOCK_EXCL);
310 	error = xfs_bmapi_write(tp, quotip, dqp->q_fileoffset,
311 			XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA,
312 			XFS_QM_DQALLOC_SPACE_RES(mp), &map, &nmaps);
313 	if (error)
314 		return error;
315 	ASSERT(map.br_blockcount == XFS_DQUOT_CLUSTER_SIZE_FSB);
316 	ASSERT(nmaps == 1);
317 	ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
318 	       (map.br_startblock != HOLESTARTBLOCK));
319 
320 	/*
321 	 * Keep track of the blkno to save a lookup later
322 	 */
323 	dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
324 
325 	/* now we can just get the buffer (there's nothing to read yet) */
326 	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, dqp->q_blkno,
327 			mp->m_quotainfo->qi_dqchunklen, 0);
328 	if (!bp)
329 		return -ENOMEM;
330 	bp->b_ops = &xfs_dquot_buf_ops;
331 
332 	/*
333 	 * Make a chunk of dquots out of this buffer and log
334 	 * the entire thing.
335 	 */
336 	xfs_qm_init_dquot_blk(tp, mp, be32_to_cpu(dqp->q_core.d_id),
337 			      dqp->dq_flags & XFS_DQ_ALLTYPES, bp);
338 	xfs_buf_set_ref(bp, XFS_DQUOT_REF);
339 
340 	/*
341 	 * Hold the buffer and join it to the dfops so that we'll still own
342 	 * the buffer when we return to the caller.  The buffer disposal on
343 	 * error must be paid attention to very carefully, as it has been
344 	 * broken since commit efa092f3d4c6 "[XFS] Fixes a bug in the quota
345 	 * code when allocating a new dquot record" in 2005, and the later
346 	 * conversion to xfs_defer_ops in commit 310a75a3c6c747 failed to keep
347 	 * the buffer locked across the _defer_finish call.  We can now do
348 	 * this correctly with xfs_defer_bjoin.
349 	 *
350 	 * Above, we allocated a disk block for the dquot information and used
351 	 * get_buf to initialize the dquot. If the _defer_finish fails, the old
352 	 * transaction is gone but the new buffer is not joined or held to any
353 	 * transaction, so we must _buf_relse it.
354 	 *
355 	 * If everything succeeds, the caller of this function is returned a
356 	 * buffer that is locked and held to the transaction.  The caller
357 	 * is responsible for unlocking any buffer passed back, either
358 	 * manually or by committing the transaction.
359 	 */
360 	xfs_trans_bhold(tp, bp);
361 	error = xfs_defer_finish(tpp);
362 	tp = *tpp;
363 	if (error) {
364 		xfs_buf_relse(bp);
365 		return error;
366 	}
367 	*bpp = bp;
368 	return 0;
369 }
370 
371 /*
372  * Read in the in-core dquot's on-disk metadata and return the buffer.
373  * Returns ENOENT to signal a hole.
374  */
375 STATIC int
376 xfs_dquot_disk_read(
377 	struct xfs_mount	*mp,
378 	struct xfs_dquot	*dqp,
379 	struct xfs_buf		**bpp)
380 {
381 	struct xfs_bmbt_irec	map;
382 	struct xfs_buf		*bp;
383 	struct xfs_inode	*quotip = xfs_quota_inode(mp, dqp->dq_flags);
384 	uint			lock_mode;
385 	int			nmaps = 1;
386 	int			error;
387 
388 	lock_mode = xfs_ilock_data_map_shared(quotip);
389 	if (!xfs_this_quota_on(mp, dqp->dq_flags)) {
390 		/*
391 		 * Return if this type of quotas is turned off while we
392 		 * didn't have the quota inode lock.
393 		 */
394 		xfs_iunlock(quotip, lock_mode);
395 		return -ESRCH;
396 	}
397 
398 	/*
399 	 * Find the block map; no allocations yet
400 	 */
401 	error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
402 			XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
403 	xfs_iunlock(quotip, lock_mode);
404 	if (error)
405 		return error;
406 
407 	ASSERT(nmaps == 1);
408 	ASSERT(map.br_blockcount >= 1);
409 	ASSERT(map.br_startblock != DELAYSTARTBLOCK);
410 	if (map.br_startblock == HOLESTARTBLOCK)
411 		return -ENOENT;
412 
413 	trace_xfs_dqtobp_read(dqp);
414 
415 	/*
416 	 * store the blkno etc so that we don't have to do the
417 	 * mapping all the time
418 	 */
419 	dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
420 
421 	error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,
422 			mp->m_quotainfo->qi_dqchunklen, 0, &bp,
423 			&xfs_dquot_buf_ops);
424 	if (error) {
425 		ASSERT(bp == NULL);
426 		return error;
427 	}
428 
429 	ASSERT(xfs_buf_islocked(bp));
430 	xfs_buf_set_ref(bp, XFS_DQUOT_REF);
431 	*bpp = bp;
432 
433 	return 0;
434 }
435 
436 /* Allocate and initialize everything we need for an incore dquot. */
437 STATIC struct xfs_dquot *
438 xfs_dquot_alloc(
439 	struct xfs_mount	*mp,
440 	xfs_dqid_t		id,
441 	uint			type)
442 {
443 	struct xfs_dquot	*dqp;
444 
445 	dqp = kmem_zone_zalloc(xfs_qm_dqzone, KM_SLEEP);
446 
447 	dqp->dq_flags = type;
448 	dqp->q_core.d_id = cpu_to_be32(id);
449 	dqp->q_mount = mp;
450 	INIT_LIST_HEAD(&dqp->q_lru);
451 	mutex_init(&dqp->q_qlock);
452 	init_waitqueue_head(&dqp->q_pinwait);
453 	dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
454 	/*
455 	 * Offset of dquot in the (fixed sized) dquot chunk.
456 	 */
457 	dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *
458 			sizeof(xfs_dqblk_t);
459 
460 	/*
461 	 * Because we want to use a counting completion, complete
462 	 * the flush completion once to allow a single access to
463 	 * the flush completion without blocking.
464 	 */
465 	init_completion(&dqp->q_flush);
466 	complete(&dqp->q_flush);
467 
468 	/*
469 	 * Make sure group quotas have a different lock class than user
470 	 * quotas.
471 	 */
472 	switch (type) {
473 	case XFS_DQ_USER:
474 		/* uses the default lock class */
475 		break;
476 	case XFS_DQ_GROUP:
477 		lockdep_set_class(&dqp->q_qlock, &xfs_dquot_group_class);
478 		break;
479 	case XFS_DQ_PROJ:
480 		lockdep_set_class(&dqp->q_qlock, &xfs_dquot_project_class);
481 		break;
482 	default:
483 		ASSERT(0);
484 		break;
485 	}
486 
487 	xfs_qm_dquot_logitem_init(dqp);
488 
489 	XFS_STATS_INC(mp, xs_qm_dquot);
490 	return dqp;
491 }
492 
493 /* Copy the in-core quota fields in from the on-disk buffer. */
494 STATIC void
495 xfs_dquot_from_disk(
496 	struct xfs_dquot	*dqp,
497 	struct xfs_buf		*bp)
498 {
499 	struct xfs_disk_dquot	*ddqp = bp->b_addr + dqp->q_bufoffset;
500 
501 	/* copy everything from disk dquot to the incore dquot */
502 	memcpy(&dqp->q_core, ddqp, sizeof(xfs_disk_dquot_t));
503 
504 	/*
505 	 * Reservation counters are defined as reservation plus current usage
506 	 * to avoid having to add every time.
507 	 */
508 	dqp->q_res_bcount = be64_to_cpu(ddqp->d_bcount);
509 	dqp->q_res_icount = be64_to_cpu(ddqp->d_icount);
510 	dqp->q_res_rtbcount = be64_to_cpu(ddqp->d_rtbcount);
511 
512 	/* initialize the dquot speculative prealloc thresholds */
513 	xfs_dquot_set_prealloc_limits(dqp);
514 }
515 
516 /* Allocate and initialize the dquot buffer for this in-core dquot. */
517 static int
518 xfs_qm_dqread_alloc(
519 	struct xfs_mount	*mp,
520 	struct xfs_dquot	*dqp,
521 	struct xfs_buf		**bpp)
522 {
523 	struct xfs_trans	*tp;
524 	struct xfs_buf		*bp;
525 	int			error;
526 
527 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_dqalloc,
528 			XFS_QM_DQALLOC_SPACE_RES(mp), 0, 0, &tp);
529 	if (error)
530 		goto err;
531 
532 	error = xfs_dquot_disk_alloc(&tp, dqp, &bp);
533 	if (error)
534 		goto err_cancel;
535 
536 	error = xfs_trans_commit(tp);
537 	if (error) {
538 		/*
539 		 * Buffer was held to the transaction, so we have to unlock it
540 		 * manually here because we're not passing it back.
541 		 */
542 		xfs_buf_relse(bp);
543 		goto err;
544 	}
545 	*bpp = bp;
546 	return 0;
547 
548 err_cancel:
549 	xfs_trans_cancel(tp);
550 err:
551 	return error;
552 }
553 
554 /*
555  * Read in the ondisk dquot using dqtobp() then copy it to an incore version,
556  * and release the buffer immediately.  If @can_alloc is true, fill any
557  * holes in the on-disk metadata.
558  */
559 static int
560 xfs_qm_dqread(
561 	struct xfs_mount	*mp,
562 	xfs_dqid_t		id,
563 	uint			type,
564 	bool			can_alloc,
565 	struct xfs_dquot	**dqpp)
566 {
567 	struct xfs_dquot	*dqp;
568 	struct xfs_buf		*bp;
569 	int			error;
570 
571 	dqp = xfs_dquot_alloc(mp, id, type);
572 	trace_xfs_dqread(dqp);
573 
574 	/* Try to read the buffer, allocating if necessary. */
575 	error = xfs_dquot_disk_read(mp, dqp, &bp);
576 	if (error == -ENOENT && can_alloc)
577 		error = xfs_qm_dqread_alloc(mp, dqp, &bp);
578 	if (error)
579 		goto err;
580 
581 	/*
582 	 * At this point we should have a clean locked buffer.  Copy the data
583 	 * to the incore dquot and release the buffer since the incore dquot
584 	 * has its own locking protocol so we needn't tie up the buffer any
585 	 * further.
586 	 */
587 	ASSERT(xfs_buf_islocked(bp));
588 	xfs_dquot_from_disk(dqp, bp);
589 
590 	xfs_buf_relse(bp);
591 	*dqpp = dqp;
592 	return error;
593 
594 err:
595 	trace_xfs_dqread_fail(dqp);
596 	xfs_qm_dqdestroy(dqp);
597 	*dqpp = NULL;
598 	return error;
599 }
600 
601 /*
602  * Advance to the next id in the current chunk, or if at the
603  * end of the chunk, skip ahead to first id in next allocated chunk
604  * using the SEEK_DATA interface.
605  */
606 static int
607 xfs_dq_get_next_id(
608 	struct xfs_mount	*mp,
609 	uint			type,
610 	xfs_dqid_t		*id)
611 {
612 	struct xfs_inode	*quotip = xfs_quota_inode(mp, type);
613 	xfs_dqid_t		next_id = *id + 1; /* simple advance */
614 	uint			lock_flags;
615 	struct xfs_bmbt_irec	got;
616 	struct xfs_iext_cursor	cur;
617 	xfs_fsblock_t		start;
618 	int			error = 0;
619 
620 	/* If we'd wrap past the max ID, stop */
621 	if (next_id < *id)
622 		return -ENOENT;
623 
624 	/* If new ID is within the current chunk, advancing it sufficed */
625 	if (next_id % mp->m_quotainfo->qi_dqperchunk) {
626 		*id = next_id;
627 		return 0;
628 	}
629 
630 	/* Nope, next_id is now past the current chunk, so find the next one */
631 	start = (xfs_fsblock_t)next_id / mp->m_quotainfo->qi_dqperchunk;
632 
633 	lock_flags = xfs_ilock_data_map_shared(quotip);
634 	if (!(quotip->i_df.if_flags & XFS_IFEXTENTS)) {
635 		error = xfs_iread_extents(NULL, quotip, XFS_DATA_FORK);
636 		if (error)
637 			return error;
638 	}
639 
640 	if (xfs_iext_lookup_extent(quotip, &quotip->i_df, start, &cur, &got)) {
641 		/* contiguous chunk, bump startoff for the id calculation */
642 		if (got.br_startoff < start)
643 			got.br_startoff = start;
644 		*id = got.br_startoff * mp->m_quotainfo->qi_dqperchunk;
645 	} else {
646 		error = -ENOENT;
647 	}
648 
649 	xfs_iunlock(quotip, lock_flags);
650 
651 	return error;
652 }
653 
654 /*
655  * Look up the dquot in the in-core cache.  If found, the dquot is returned
656  * locked and ready to go.
657  */
658 static struct xfs_dquot *
659 xfs_qm_dqget_cache_lookup(
660 	struct xfs_mount	*mp,
661 	struct xfs_quotainfo	*qi,
662 	struct radix_tree_root	*tree,
663 	xfs_dqid_t		id)
664 {
665 	struct xfs_dquot	*dqp;
666 
667 restart:
668 	mutex_lock(&qi->qi_tree_lock);
669 	dqp = radix_tree_lookup(tree, id);
670 	if (!dqp) {
671 		mutex_unlock(&qi->qi_tree_lock);
672 		XFS_STATS_INC(mp, xs_qm_dqcachemisses);
673 		return NULL;
674 	}
675 
676 	xfs_dqlock(dqp);
677 	if (dqp->dq_flags & XFS_DQ_FREEING) {
678 		xfs_dqunlock(dqp);
679 		mutex_unlock(&qi->qi_tree_lock);
680 		trace_xfs_dqget_freeing(dqp);
681 		delay(1);
682 		goto restart;
683 	}
684 
685 	dqp->q_nrefs++;
686 	mutex_unlock(&qi->qi_tree_lock);
687 
688 	trace_xfs_dqget_hit(dqp);
689 	XFS_STATS_INC(mp, xs_qm_dqcachehits);
690 	return dqp;
691 }
692 
693 /*
694  * Try to insert a new dquot into the in-core cache.  If an error occurs the
695  * caller should throw away the dquot and start over.  Otherwise, the dquot
696  * is returned locked (and held by the cache) as if there had been a cache
697  * hit.
698  */
699 static int
700 xfs_qm_dqget_cache_insert(
701 	struct xfs_mount	*mp,
702 	struct xfs_quotainfo	*qi,
703 	struct radix_tree_root	*tree,
704 	xfs_dqid_t		id,
705 	struct xfs_dquot	*dqp)
706 {
707 	int			error;
708 
709 	mutex_lock(&qi->qi_tree_lock);
710 	error = radix_tree_insert(tree, id, dqp);
711 	if (unlikely(error)) {
712 		/* Duplicate found!  Caller must try again. */
713 		WARN_ON(error != -EEXIST);
714 		mutex_unlock(&qi->qi_tree_lock);
715 		trace_xfs_dqget_dup(dqp);
716 		return error;
717 	}
718 
719 	/* Return a locked dquot to the caller, with a reference taken. */
720 	xfs_dqlock(dqp);
721 	dqp->q_nrefs = 1;
722 
723 	qi->qi_dquots++;
724 	mutex_unlock(&qi->qi_tree_lock);
725 
726 	return 0;
727 }
728 
729 /* Check our input parameters. */
730 static int
731 xfs_qm_dqget_checks(
732 	struct xfs_mount	*mp,
733 	uint			type)
734 {
735 	if (WARN_ON_ONCE(!XFS_IS_QUOTA_RUNNING(mp)))
736 		return -ESRCH;
737 
738 	switch (type) {
739 	case XFS_DQ_USER:
740 		if (!XFS_IS_UQUOTA_ON(mp))
741 			return -ESRCH;
742 		return 0;
743 	case XFS_DQ_GROUP:
744 		if (!XFS_IS_GQUOTA_ON(mp))
745 			return -ESRCH;
746 		return 0;
747 	case XFS_DQ_PROJ:
748 		if (!XFS_IS_PQUOTA_ON(mp))
749 			return -ESRCH;
750 		return 0;
751 	default:
752 		WARN_ON_ONCE(0);
753 		return -EINVAL;
754 	}
755 }
756 
757 /*
758  * Given the file system, id, and type (UDQUOT/GDQUOT), return a a locked
759  * dquot, doing an allocation (if requested) as needed.
760  */
761 int
762 xfs_qm_dqget(
763 	struct xfs_mount	*mp,
764 	xfs_dqid_t		id,
765 	uint			type,
766 	bool			can_alloc,
767 	struct xfs_dquot	**O_dqpp)
768 {
769 	struct xfs_quotainfo	*qi = mp->m_quotainfo;
770 	struct radix_tree_root	*tree = xfs_dquot_tree(qi, type);
771 	struct xfs_dquot	*dqp;
772 	int			error;
773 
774 	error = xfs_qm_dqget_checks(mp, type);
775 	if (error)
776 		return error;
777 
778 restart:
779 	dqp = xfs_qm_dqget_cache_lookup(mp, qi, tree, id);
780 	if (dqp) {
781 		*O_dqpp = dqp;
782 		return 0;
783 	}
784 
785 	error = xfs_qm_dqread(mp, id, type, can_alloc, &dqp);
786 	if (error)
787 		return error;
788 
789 	error = xfs_qm_dqget_cache_insert(mp, qi, tree, id, dqp);
790 	if (error) {
791 		/*
792 		 * Duplicate found. Just throw away the new dquot and start
793 		 * over.
794 		 */
795 		xfs_qm_dqdestroy(dqp);
796 		XFS_STATS_INC(mp, xs_qm_dquot_dups);
797 		goto restart;
798 	}
799 
800 	trace_xfs_dqget_miss(dqp);
801 	*O_dqpp = dqp;
802 	return 0;
803 }
804 
805 /*
806  * Given a dquot id and type, read and initialize a dquot from the on-disk
807  * metadata.  This function is only for use during quota initialization so
808  * it ignores the dquot cache assuming that the dquot shrinker isn't set up.
809  * The caller is responsible for _qm_dqdestroy'ing the returned dquot.
810  */
811 int
812 xfs_qm_dqget_uncached(
813 	struct xfs_mount	*mp,
814 	xfs_dqid_t		id,
815 	uint			type,
816 	struct xfs_dquot	**dqpp)
817 {
818 	int			error;
819 
820 	error = xfs_qm_dqget_checks(mp, type);
821 	if (error)
822 		return error;
823 
824 	return xfs_qm_dqread(mp, id, type, 0, dqpp);
825 }
826 
827 /* Return the quota id for a given inode and type. */
828 xfs_dqid_t
829 xfs_qm_id_for_quotatype(
830 	struct xfs_inode	*ip,
831 	uint			type)
832 {
833 	switch (type) {
834 	case XFS_DQ_USER:
835 		return ip->i_d.di_uid;
836 	case XFS_DQ_GROUP:
837 		return ip->i_d.di_gid;
838 	case XFS_DQ_PROJ:
839 		return xfs_get_projid(ip);
840 	}
841 	ASSERT(0);
842 	return 0;
843 }
844 
845 /*
846  * Return the dquot for a given inode and type.  If @can_alloc is true, then
847  * allocate blocks if needed.  The inode's ILOCK must be held and it must not
848  * have already had an inode attached.
849  */
850 int
851 xfs_qm_dqget_inode(
852 	struct xfs_inode	*ip,
853 	uint			type,
854 	bool			can_alloc,
855 	struct xfs_dquot	**O_dqpp)
856 {
857 	struct xfs_mount	*mp = ip->i_mount;
858 	struct xfs_quotainfo	*qi = mp->m_quotainfo;
859 	struct radix_tree_root	*tree = xfs_dquot_tree(qi, type);
860 	struct xfs_dquot	*dqp;
861 	xfs_dqid_t		id;
862 	int			error;
863 
864 	error = xfs_qm_dqget_checks(mp, type);
865 	if (error)
866 		return error;
867 
868 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
869 	ASSERT(xfs_inode_dquot(ip, type) == NULL);
870 
871 	id = xfs_qm_id_for_quotatype(ip, type);
872 
873 restart:
874 	dqp = xfs_qm_dqget_cache_lookup(mp, qi, tree, id);
875 	if (dqp) {
876 		*O_dqpp = dqp;
877 		return 0;
878 	}
879 
880 	/*
881 	 * Dquot cache miss. We don't want to keep the inode lock across
882 	 * a (potential) disk read. Also we don't want to deal with the lock
883 	 * ordering between quotainode and this inode. OTOH, dropping the inode
884 	 * lock here means dealing with a chown that can happen before
885 	 * we re-acquire the lock.
886 	 */
887 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
888 	error = xfs_qm_dqread(mp, id, type, can_alloc, &dqp);
889 	xfs_ilock(ip, XFS_ILOCK_EXCL);
890 	if (error)
891 		return error;
892 
893 	/*
894 	 * A dquot could be attached to this inode by now, since we had
895 	 * dropped the ilock.
896 	 */
897 	if (xfs_this_quota_on(mp, type)) {
898 		struct xfs_dquot	*dqp1;
899 
900 		dqp1 = xfs_inode_dquot(ip, type);
901 		if (dqp1) {
902 			xfs_qm_dqdestroy(dqp);
903 			dqp = dqp1;
904 			xfs_dqlock(dqp);
905 			goto dqret;
906 		}
907 	} else {
908 		/* inode stays locked on return */
909 		xfs_qm_dqdestroy(dqp);
910 		return -ESRCH;
911 	}
912 
913 	error = xfs_qm_dqget_cache_insert(mp, qi, tree, id, dqp);
914 	if (error) {
915 		/*
916 		 * Duplicate found. Just throw away the new dquot and start
917 		 * over.
918 		 */
919 		xfs_qm_dqdestroy(dqp);
920 		XFS_STATS_INC(mp, xs_qm_dquot_dups);
921 		goto restart;
922 	}
923 
924 dqret:
925 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
926 	trace_xfs_dqget_miss(dqp);
927 	*O_dqpp = dqp;
928 	return 0;
929 }
930 
931 /*
932  * Starting at @id and progressing upwards, look for an initialized incore
933  * dquot, lock it, and return it.
934  */
935 int
936 xfs_qm_dqget_next(
937 	struct xfs_mount	*mp,
938 	xfs_dqid_t		id,
939 	uint			type,
940 	struct xfs_dquot	**dqpp)
941 {
942 	struct xfs_dquot	*dqp;
943 	int			error = 0;
944 
945 	*dqpp = NULL;
946 	for (; !error; error = xfs_dq_get_next_id(mp, type, &id)) {
947 		error = xfs_qm_dqget(mp, id, type, false, &dqp);
948 		if (error == -ENOENT)
949 			continue;
950 		else if (error != 0)
951 			break;
952 
953 		if (!XFS_IS_DQUOT_UNINITIALIZED(dqp)) {
954 			*dqpp = dqp;
955 			return 0;
956 		}
957 
958 		xfs_qm_dqput(dqp);
959 	}
960 
961 	return error;
962 }
963 
964 /*
965  * Release a reference to the dquot (decrement ref-count) and unlock it.
966  *
967  * If there is a group quota attached to this dquot, carefully release that
968  * too without tripping over deadlocks'n'stuff.
969  */
970 void
971 xfs_qm_dqput(
972 	struct xfs_dquot	*dqp)
973 {
974 	ASSERT(dqp->q_nrefs > 0);
975 	ASSERT(XFS_DQ_IS_LOCKED(dqp));
976 
977 	trace_xfs_dqput(dqp);
978 
979 	if (--dqp->q_nrefs == 0) {
980 		struct xfs_quotainfo	*qi = dqp->q_mount->m_quotainfo;
981 		trace_xfs_dqput_free(dqp);
982 
983 		if (list_lru_add(&qi->qi_lru, &dqp->q_lru))
984 			XFS_STATS_INC(dqp->q_mount, xs_qm_dquot_unused);
985 	}
986 	xfs_dqunlock(dqp);
987 }
988 
989 /*
990  * Release a dquot. Flush it if dirty, then dqput() it.
991  * dquot must not be locked.
992  */
993 void
994 xfs_qm_dqrele(
995 	xfs_dquot_t	*dqp)
996 {
997 	if (!dqp)
998 		return;
999 
1000 	trace_xfs_dqrele(dqp);
1001 
1002 	xfs_dqlock(dqp);
1003 	/*
1004 	 * We don't care to flush it if the dquot is dirty here.
1005 	 * That will create stutters that we want to avoid.
1006 	 * Instead we do a delayed write when we try to reclaim
1007 	 * a dirty dquot. Also xfs_sync will take part of the burden...
1008 	 */
1009 	xfs_qm_dqput(dqp);
1010 }
1011 
1012 /*
1013  * This is the dquot flushing I/O completion routine.  It is called
1014  * from interrupt level when the buffer containing the dquot is
1015  * flushed to disk.  It is responsible for removing the dquot logitem
1016  * from the AIL if it has not been re-logged, and unlocking the dquot's
1017  * flush lock. This behavior is very similar to that of inodes..
1018  */
1019 STATIC void
1020 xfs_qm_dqflush_done(
1021 	struct xfs_buf		*bp,
1022 	struct xfs_log_item	*lip)
1023 {
1024 	xfs_dq_logitem_t	*qip = (struct xfs_dq_logitem *)lip;
1025 	xfs_dquot_t		*dqp = qip->qli_dquot;
1026 	struct xfs_ail		*ailp = lip->li_ailp;
1027 
1028 	/*
1029 	 * We only want to pull the item from the AIL if its
1030 	 * location in the log has not changed since we started the flush.
1031 	 * Thus, we only bother if the dquot's lsn has
1032 	 * not changed. First we check the lsn outside the lock
1033 	 * since it's cheaper, and then we recheck while
1034 	 * holding the lock before removing the dquot from the AIL.
1035 	 */
1036 	if (test_bit(XFS_LI_IN_AIL, &lip->li_flags) &&
1037 	    ((lip->li_lsn == qip->qli_flush_lsn) ||
1038 	     test_bit(XFS_LI_FAILED, &lip->li_flags))) {
1039 
1040 		/* xfs_trans_ail_delete() drops the AIL lock. */
1041 		spin_lock(&ailp->ail_lock);
1042 		if (lip->li_lsn == qip->qli_flush_lsn) {
1043 			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
1044 		} else {
1045 			/*
1046 			 * Clear the failed state since we are about to drop the
1047 			 * flush lock
1048 			 */
1049 			xfs_clear_li_failed(lip);
1050 			spin_unlock(&ailp->ail_lock);
1051 		}
1052 	}
1053 
1054 	/*
1055 	 * Release the dq's flush lock since we're done with it.
1056 	 */
1057 	xfs_dqfunlock(dqp);
1058 }
1059 
1060 /*
1061  * Write a modified dquot to disk.
1062  * The dquot must be locked and the flush lock too taken by caller.
1063  * The flush lock will not be unlocked until the dquot reaches the disk,
1064  * but the dquot is free to be unlocked and modified by the caller
1065  * in the interim. Dquot is still locked on return. This behavior is
1066  * identical to that of inodes.
1067  */
1068 int
1069 xfs_qm_dqflush(
1070 	struct xfs_dquot	*dqp,
1071 	struct xfs_buf		**bpp)
1072 {
1073 	struct xfs_mount	*mp = dqp->q_mount;
1074 	struct xfs_buf		*bp;
1075 	struct xfs_dqblk	*dqb;
1076 	struct xfs_disk_dquot	*ddqp;
1077 	xfs_failaddr_t		fa;
1078 	int			error;
1079 
1080 	ASSERT(XFS_DQ_IS_LOCKED(dqp));
1081 	ASSERT(!completion_done(&dqp->q_flush));
1082 
1083 	trace_xfs_dqflush(dqp);
1084 
1085 	*bpp = NULL;
1086 
1087 	xfs_qm_dqunpin_wait(dqp);
1088 
1089 	/*
1090 	 * This may have been unpinned because the filesystem is shutting
1091 	 * down forcibly. If that's the case we must not write this dquot
1092 	 * to disk, because the log record didn't make it to disk.
1093 	 *
1094 	 * We also have to remove the log item from the AIL in this case,
1095 	 * as we wait for an emptry AIL as part of the unmount process.
1096 	 */
1097 	if (XFS_FORCED_SHUTDOWN(mp)) {
1098 		struct xfs_log_item	*lip = &dqp->q_logitem.qli_item;
1099 		dqp->dq_flags &= ~XFS_DQ_DIRTY;
1100 
1101 		xfs_trans_ail_remove(lip, SHUTDOWN_CORRUPT_INCORE);
1102 
1103 		error = -EIO;
1104 		goto out_unlock;
1105 	}
1106 
1107 	/*
1108 	 * Get the buffer containing the on-disk dquot
1109 	 */
1110 	error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,
1111 				   mp->m_quotainfo->qi_dqchunklen, 0, &bp,
1112 				   &xfs_dquot_buf_ops);
1113 	if (error)
1114 		goto out_unlock;
1115 
1116 	/*
1117 	 * Calculate the location of the dquot inside the buffer.
1118 	 */
1119 	dqb = bp->b_addr + dqp->q_bufoffset;
1120 	ddqp = &dqb->dd_diskdq;
1121 
1122 	/*
1123 	 * A simple sanity check in case we got a corrupted dquot.
1124 	 */
1125 	fa = xfs_dqblk_verify(mp, dqb, be32_to_cpu(ddqp->d_id), 0);
1126 	if (fa) {
1127 		xfs_alert(mp, "corrupt dquot ID 0x%x in memory at %pS",
1128 				be32_to_cpu(ddqp->d_id), fa);
1129 		xfs_buf_relse(bp);
1130 		xfs_dqfunlock(dqp);
1131 		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
1132 		return -EIO;
1133 	}
1134 
1135 	/* This is the only portion of data that needs to persist */
1136 	memcpy(ddqp, &dqp->q_core, sizeof(xfs_disk_dquot_t));
1137 
1138 	/*
1139 	 * Clear the dirty field and remember the flush lsn for later use.
1140 	 */
1141 	dqp->dq_flags &= ~XFS_DQ_DIRTY;
1142 
1143 	xfs_trans_ail_copy_lsn(mp->m_ail, &dqp->q_logitem.qli_flush_lsn,
1144 					&dqp->q_logitem.qli_item.li_lsn);
1145 
1146 	/*
1147 	 * copy the lsn into the on-disk dquot now while we have the in memory
1148 	 * dquot here. This can't be done later in the write verifier as we
1149 	 * can't get access to the log item at that point in time.
1150 	 *
1151 	 * We also calculate the CRC here so that the on-disk dquot in the
1152 	 * buffer always has a valid CRC. This ensures there is no possibility
1153 	 * of a dquot without an up-to-date CRC getting to disk.
1154 	 */
1155 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
1156 		dqb->dd_lsn = cpu_to_be64(dqp->q_logitem.qli_item.li_lsn);
1157 		xfs_update_cksum((char *)dqb, sizeof(struct xfs_dqblk),
1158 				 XFS_DQUOT_CRC_OFF);
1159 	}
1160 
1161 	/*
1162 	 * Attach an iodone routine so that we can remove this dquot from the
1163 	 * AIL and release the flush lock once the dquot is synced to disk.
1164 	 */
1165 	xfs_buf_attach_iodone(bp, xfs_qm_dqflush_done,
1166 				  &dqp->q_logitem.qli_item);
1167 
1168 	/*
1169 	 * If the buffer is pinned then push on the log so we won't
1170 	 * get stuck waiting in the write for too long.
1171 	 */
1172 	if (xfs_buf_ispinned(bp)) {
1173 		trace_xfs_dqflush_force(dqp);
1174 		xfs_log_force(mp, 0);
1175 	}
1176 
1177 	trace_xfs_dqflush_done(dqp);
1178 	*bpp = bp;
1179 	return 0;
1180 
1181 out_unlock:
1182 	xfs_dqfunlock(dqp);
1183 	return -EIO;
1184 }
1185 
1186 /*
1187  * Lock two xfs_dquot structures.
1188  *
1189  * To avoid deadlocks we always lock the quota structure with
1190  * the lowerd id first.
1191  */
1192 void
1193 xfs_dqlock2(
1194 	xfs_dquot_t	*d1,
1195 	xfs_dquot_t	*d2)
1196 {
1197 	if (d1 && d2) {
1198 		ASSERT(d1 != d2);
1199 		if (be32_to_cpu(d1->q_core.d_id) >
1200 		    be32_to_cpu(d2->q_core.d_id)) {
1201 			mutex_lock(&d2->q_qlock);
1202 			mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED);
1203 		} else {
1204 			mutex_lock(&d1->q_qlock);
1205 			mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED);
1206 		}
1207 	} else if (d1) {
1208 		mutex_lock(&d1->q_qlock);
1209 	} else if (d2) {
1210 		mutex_lock(&d2->q_qlock);
1211 	}
1212 }
1213 
1214 int __init
1215 xfs_qm_init(void)
1216 {
1217 	xfs_qm_dqzone =
1218 		kmem_zone_init(sizeof(struct xfs_dquot), "xfs_dquot");
1219 	if (!xfs_qm_dqzone)
1220 		goto out;
1221 
1222 	xfs_qm_dqtrxzone =
1223 		kmem_zone_init(sizeof(struct xfs_dquot_acct), "xfs_dqtrx");
1224 	if (!xfs_qm_dqtrxzone)
1225 		goto out_free_dqzone;
1226 
1227 	return 0;
1228 
1229 out_free_dqzone:
1230 	kmem_zone_destroy(xfs_qm_dqzone);
1231 out:
1232 	return -ENOMEM;
1233 }
1234 
1235 void
1236 xfs_qm_exit(void)
1237 {
1238 	kmem_zone_destroy(xfs_qm_dqtrxzone);
1239 	kmem_zone_destroy(xfs_qm_dqzone);
1240 }
1241 
1242 /*
1243  * Iterate every dquot of a particular type.  The caller must ensure that the
1244  * particular quota type is active.  iter_fn can return negative error codes,
1245  * or XFS_BTREE_QUERY_RANGE_ABORT to indicate that it wants to stop iterating.
1246  */
1247 int
1248 xfs_qm_dqiterate(
1249 	struct xfs_mount	*mp,
1250 	uint			dqtype,
1251 	xfs_qm_dqiterate_fn	iter_fn,
1252 	void			*priv)
1253 {
1254 	struct xfs_dquot	*dq;
1255 	xfs_dqid_t		id = 0;
1256 	int			error;
1257 
1258 	do {
1259 		error = xfs_qm_dqget_next(mp, id, dqtype, &dq);
1260 		if (error == -ENOENT)
1261 			return 0;
1262 		if (error)
1263 			return error;
1264 
1265 		error = iter_fn(dq, dqtype, priv);
1266 		id = be32_to_cpu(dq->q_core.d_id);
1267 		xfs_qm_dqput(dq);
1268 		id++;
1269 	} while (error == 0 && id != 0);
1270 
1271 	return error;
1272 }
1273