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1// SPDX-License-Identifier: GPL-2.02/*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_quota.h"18#include "xfs_trans.h"19#include "xfs_buf_item.h"20#include "xfs_trans_space.h"21#include "xfs_trans_priv.h"22#include "xfs_qm.h"23#include "xfs_trace.h"24#include "xfs_log.h"25#include "xfs_bmap_btree.h"26#include "xfs_error.h"27#include "xfs_health.h"28 29/*30 * Lock order:31 *32 * ip->i_lock33 *   qi->qi_tree_lock34 *     dquot->q_qlock (xfs_dqlock() and friends)35 *       dquot->q_flush (xfs_dqflock() and friends)36 *       qi->qi_lru_lock37 *38 * If two dquots need to be locked the order is user before group/project,39 * otherwise by the lowest id first, see xfs_dqlock2.40 */41 42struct kmem_cache		*xfs_dqtrx_cache;43static struct kmem_cache	*xfs_dquot_cache;44 45static struct lock_class_key xfs_dquot_group_class;46static struct lock_class_key xfs_dquot_project_class;47 48/* Record observations of quota corruption with the health tracking system. */49static void50xfs_dquot_mark_sick(51	struct xfs_dquot	*dqp)52{53	struct xfs_mount	*mp = dqp->q_mount;54 55	switch (dqp->q_type) {56	case XFS_DQTYPE_USER:57		xfs_fs_mark_sick(mp, XFS_SICK_FS_UQUOTA);58		break;59	case XFS_DQTYPE_GROUP:60		xfs_fs_mark_sick(mp, XFS_SICK_FS_GQUOTA);61		break;62	case XFS_DQTYPE_PROJ:63		xfs_fs_mark_sick(mp, XFS_SICK_FS_PQUOTA);64		break;65	default:66		ASSERT(0);67		break;68	}69}70 71/*72 * This is called to free all the memory associated with a dquot73 */74void75xfs_qm_dqdestroy(76	struct xfs_dquot	*dqp)77{78	ASSERT(list_empty(&dqp->q_lru));79 80	kvfree(dqp->q_logitem.qli_item.li_lv_shadow);81	mutex_destroy(&dqp->q_qlock);82 83	XFS_STATS_DEC(dqp->q_mount, xs_qm_dquot);84	kmem_cache_free(xfs_dquot_cache, dqp);85}86 87/*88 * If default limits are in force, push them into the dquot now.89 * We overwrite the dquot limits only if they are zero and this90 * is not the root dquot.91 */92void93xfs_qm_adjust_dqlimits(94	struct xfs_dquot	*dq)95{96	struct xfs_mount	*mp = dq->q_mount;97	struct xfs_quotainfo	*q = mp->m_quotainfo;98	struct xfs_def_quota	*defq;99	int			prealloc = 0;100 101	ASSERT(dq->q_id);102	defq = xfs_get_defquota(q, xfs_dquot_type(dq));103 104	if (!dq->q_blk.softlimit) {105		dq->q_blk.softlimit = defq->blk.soft;106		prealloc = 1;107	}108	if (!dq->q_blk.hardlimit) {109		dq->q_blk.hardlimit = defq->blk.hard;110		prealloc = 1;111	}112	if (!dq->q_ino.softlimit)113		dq->q_ino.softlimit = defq->ino.soft;114	if (!dq->q_ino.hardlimit)115		dq->q_ino.hardlimit = defq->ino.hard;116	if (!dq->q_rtb.softlimit)117		dq->q_rtb.softlimit = defq->rtb.soft;118	if (!dq->q_rtb.hardlimit)119		dq->q_rtb.hardlimit = defq->rtb.hard;120 121	if (prealloc)122		xfs_dquot_set_prealloc_limits(dq);123}124 125/* Set the expiration time of a quota's grace period. */126time64_t127xfs_dquot_set_timeout(128	struct xfs_mount	*mp,129	time64_t		timeout)130{131	struct xfs_quotainfo	*qi = mp->m_quotainfo;132 133	return clamp_t(time64_t, timeout, qi->qi_expiry_min,134					  qi->qi_expiry_max);135}136 137/* Set the length of the default grace period. */138time64_t139xfs_dquot_set_grace_period(140	time64_t		grace)141{142	return clamp_t(time64_t, grace, XFS_DQ_GRACE_MIN, XFS_DQ_GRACE_MAX);143}144 145/*146 * Determine if this quota counter is over either limit and set the quota147 * timers as appropriate.148 */149static inline void150xfs_qm_adjust_res_timer(151	struct xfs_mount	*mp,152	struct xfs_dquot_res	*res,153	struct xfs_quota_limits	*qlim)154{155	ASSERT(res->hardlimit == 0 || res->softlimit <= res->hardlimit);156 157	if ((res->softlimit && res->count > res->softlimit) ||158	    (res->hardlimit && res->count > res->hardlimit)) {159		if (res->timer == 0)160			res->timer = xfs_dquot_set_timeout(mp,161					ktime_get_real_seconds() + qlim->time);162	} else {163		res->timer = 0;164	}165}166 167/*168 * Check the limits and timers of a dquot and start or reset timers169 * if necessary.170 * This gets called even when quota enforcement is OFF, which makes our171 * life a little less complicated. (We just don't reject any quota172 * reservations in that case, when enforcement is off).173 * We also return 0 as the values of the timers in Q_GETQUOTA calls, when174 * enforcement's off.175 * In contrast, warnings are a little different in that they don't176 * 'automatically' get started when limits get exceeded.  They do177 * get reset to zero, however, when we find the count to be under178 * the soft limit (they are only ever set non-zero via userspace).179 */180void181xfs_qm_adjust_dqtimers(182	struct xfs_dquot	*dq)183{184	struct xfs_mount	*mp = dq->q_mount;185	struct xfs_quotainfo	*qi = mp->m_quotainfo;186	struct xfs_def_quota	*defq;187 188	ASSERT(dq->q_id);189	defq = xfs_get_defquota(qi, xfs_dquot_type(dq));190 191	xfs_qm_adjust_res_timer(dq->q_mount, &dq->q_blk, &defq->blk);192	xfs_qm_adjust_res_timer(dq->q_mount, &dq->q_ino, &defq->ino);193	xfs_qm_adjust_res_timer(dq->q_mount, &dq->q_rtb, &defq->rtb);194}195 196/*197 * initialize a buffer full of dquots and log the whole thing198 */199void200xfs_qm_init_dquot_blk(201	struct xfs_trans	*tp,202	xfs_dqid_t		id,203	xfs_dqtype_t		type,204	struct xfs_buf		*bp)205{206	struct xfs_mount	*mp = tp->t_mountp;207	struct xfs_quotainfo	*q = mp->m_quotainfo;208	struct xfs_dqblk	*d;209	xfs_dqid_t		curid;210	unsigned int		qflag;211	unsigned int		blftype;212	int			i;213 214	ASSERT(tp);215	ASSERT(xfs_buf_islocked(bp));216 217	switch (type) {218	case XFS_DQTYPE_USER:219		qflag = XFS_UQUOTA_CHKD;220		blftype = XFS_BLF_UDQUOT_BUF;221		break;222	case XFS_DQTYPE_PROJ:223		qflag = XFS_PQUOTA_CHKD;224		blftype = XFS_BLF_PDQUOT_BUF;225		break;226	case XFS_DQTYPE_GROUP:227		qflag = XFS_GQUOTA_CHKD;228		blftype = XFS_BLF_GDQUOT_BUF;229		break;230	default:231		ASSERT(0);232		return;233	}234 235	d = bp->b_addr;236 237	/*238	 * ID of the first dquot in the block - id's are zero based.239	 */240	curid = id - (id % q->qi_dqperchunk);241	memset(d, 0, BBTOB(q->qi_dqchunklen));242	for (i = 0; i < q->qi_dqperchunk; i++, d++, curid++) {243		d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);244		d->dd_diskdq.d_version = XFS_DQUOT_VERSION;245		d->dd_diskdq.d_id = cpu_to_be32(curid);246		d->dd_diskdq.d_type = type;247		if (curid > 0 && xfs_has_bigtime(mp))248			d->dd_diskdq.d_type |= XFS_DQTYPE_BIGTIME;249		if (xfs_has_crc(mp)) {250			uuid_copy(&d->dd_uuid, &mp->m_sb.sb_meta_uuid);251			xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),252					 XFS_DQUOT_CRC_OFF);253		}254	}255 256	xfs_trans_dquot_buf(tp, bp, blftype);257 258	/*259	 * quotacheck uses delayed writes to update all the dquots on disk in an260	 * efficient manner instead of logging the individual dquot changes as261	 * they are made. However if we log the buffer allocated here and crash262	 * after quotacheck while the logged initialisation is still in the263	 * active region of the log, log recovery can replay the dquot buffer264	 * initialisation over the top of the checked dquots and corrupt quota265	 * accounting.266	 *267	 * To avoid this problem, quotacheck cannot log the initialised buffer.268	 * We must still dirty the buffer and write it back before the269	 * allocation transaction clears the log. Therefore, mark the buffer as270	 * ordered instead of logging it directly. This is safe for quotacheck271	 * because it detects and repairs allocated but initialized dquot blocks272	 * in the quota inodes.273	 */274	if (!(mp->m_qflags & qflag))275		xfs_trans_ordered_buf(tp, bp);276	else277		xfs_trans_log_buf(tp, bp, 0, BBTOB(q->qi_dqchunklen) - 1);278}279 280/*281 * Initialize the dynamic speculative preallocation thresholds. The lo/hi282 * watermarks correspond to the soft and hard limits by default. If a soft limit283 * is not specified, we use 95% of the hard limit.284 */285void286xfs_dquot_set_prealloc_limits(struct xfs_dquot *dqp)287{288	uint64_t space;289 290	dqp->q_prealloc_hi_wmark = dqp->q_blk.hardlimit;291	dqp->q_prealloc_lo_wmark = dqp->q_blk.softlimit;292	if (!dqp->q_prealloc_lo_wmark) {293		dqp->q_prealloc_lo_wmark = dqp->q_prealloc_hi_wmark;294		do_div(dqp->q_prealloc_lo_wmark, 100);295		dqp->q_prealloc_lo_wmark *= 95;296	}297 298	space = dqp->q_prealloc_hi_wmark;299 300	do_div(space, 100);301	dqp->q_low_space[XFS_QLOWSP_1_PCNT] = space;302	dqp->q_low_space[XFS_QLOWSP_3_PCNT] = space * 3;303	dqp->q_low_space[XFS_QLOWSP_5_PCNT] = space * 5;304}305 306/*307 * Ensure that the given in-core dquot has a buffer on disk backing it, and308 * return the buffer locked and held. This is called when the bmapi finds a309 * hole.310 */311STATIC int312xfs_dquot_disk_alloc(313	struct xfs_dquot	*dqp,314	struct xfs_buf		**bpp)315{316	struct xfs_bmbt_irec	map;317	struct xfs_trans	*tp;318	struct xfs_mount	*mp = dqp->q_mount;319	struct xfs_buf		*bp;320	xfs_dqtype_t		qtype = xfs_dquot_type(dqp);321	struct xfs_inode	*quotip = xfs_quota_inode(mp, qtype);322	int			nmaps = 1;323	int			error;324 325	trace_xfs_dqalloc(dqp);326 327	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_dqalloc,328			XFS_QM_DQALLOC_SPACE_RES(mp), 0, 0, &tp);329	if (error)330		return error;331 332	xfs_ilock(quotip, XFS_ILOCK_EXCL);333	xfs_trans_ijoin(tp, quotip, 0);334 335	if (!xfs_this_quota_on(dqp->q_mount, qtype)) {336		/*337		 * Return if this type of quotas is turned off while we didn't338		 * have an inode lock339		 */340		error = -ESRCH;341		goto err_cancel;342	}343 344	error = xfs_iext_count_extend(tp, quotip, XFS_DATA_FORK,345			XFS_IEXT_ADD_NOSPLIT_CNT);346	if (error)347		goto err_cancel;348 349	/* Create the block mapping. */350	error = xfs_bmapi_write(tp, quotip, dqp->q_fileoffset,351			XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA, 0, &map,352			&nmaps);353	if (error)354		goto err_cancel;355 356	ASSERT(map.br_blockcount == XFS_DQUOT_CLUSTER_SIZE_FSB);357	ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&358	       (map.br_startblock != HOLESTARTBLOCK));359 360	/*361	 * Keep track of the blkno to save a lookup later362	 */363	dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);364 365	/* now we can just get the buffer (there's nothing to read yet) */366	error = xfs_trans_get_buf(tp, mp->m_ddev_targp, dqp->q_blkno,367			mp->m_quotainfo->qi_dqchunklen, 0, &bp);368	if (error)369		goto err_cancel;370	bp->b_ops = &xfs_dquot_buf_ops;371 372	/*373	 * Make a chunk of dquots out of this buffer and log374	 * the entire thing.375	 */376	xfs_qm_init_dquot_blk(tp, dqp->q_id, qtype, bp);377	xfs_buf_set_ref(bp, XFS_DQUOT_REF);378 379	/*380	 * Hold the buffer and join it to the dfops so that we'll still own381	 * the buffer when we return to the caller.  The buffer disposal on382	 * error must be paid attention to very carefully, as it has been383	 * broken since commit efa092f3d4c6 "[XFS] Fixes a bug in the quota384	 * code when allocating a new dquot record" in 2005, and the later385	 * conversion to xfs_defer_ops in commit 310a75a3c6c747 failed to keep386	 * the buffer locked across the _defer_finish call.  We can now do387	 * this correctly with xfs_defer_bjoin.388	 *389	 * Above, we allocated a disk block for the dquot information and used390	 * get_buf to initialize the dquot. If the _defer_finish fails, the old391	 * transaction is gone but the new buffer is not joined or held to any392	 * transaction, so we must _buf_relse it.393	 *394	 * If everything succeeds, the caller of this function is returned a395	 * buffer that is locked and held to the transaction.  The caller396	 * is responsible for unlocking any buffer passed back, either397	 * manually or by committing the transaction.  On error, the buffer is398	 * released and not passed back.399	 *400	 * Keep the quota inode ILOCKed until after the transaction commit to401	 * maintain the atomicity of bmap/rmap updates.402	 */403	xfs_trans_bhold(tp, bp);404	error = xfs_trans_commit(tp);405	xfs_iunlock(quotip, XFS_ILOCK_EXCL);406	if (error) {407		xfs_buf_relse(bp);408		return error;409	}410 411	*bpp = bp;412	return 0;413 414err_cancel:415	xfs_trans_cancel(tp);416	xfs_iunlock(quotip, XFS_ILOCK_EXCL);417	return error;418}419 420/*421 * Read in the in-core dquot's on-disk metadata and return the buffer.422 * Returns ENOENT to signal a hole.423 */424STATIC int425xfs_dquot_disk_read(426	struct xfs_mount	*mp,427	struct xfs_dquot	*dqp,428	struct xfs_buf		**bpp)429{430	struct xfs_bmbt_irec	map;431	struct xfs_buf		*bp;432	xfs_dqtype_t		qtype = xfs_dquot_type(dqp);433	struct xfs_inode	*quotip = xfs_quota_inode(mp, qtype);434	uint			lock_mode;435	int			nmaps = 1;436	int			error;437 438	lock_mode = xfs_ilock_data_map_shared(quotip);439	if (!xfs_this_quota_on(mp, qtype)) {440		/*441		 * Return if this type of quotas is turned off while we442		 * didn't have the quota inode lock.443		 */444		xfs_iunlock(quotip, lock_mode);445		return -ESRCH;446	}447 448	/*449	 * Find the block map; no allocations yet450	 */451	error = xfs_bmapi_read(quotip, dqp->q_fileoffset,452			XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);453	xfs_iunlock(quotip, lock_mode);454	if (error)455		return error;456 457	ASSERT(nmaps == 1);458	ASSERT(map.br_blockcount >= 1);459	ASSERT(map.br_startblock != DELAYSTARTBLOCK);460	if (map.br_startblock == HOLESTARTBLOCK)461		return -ENOENT;462 463	trace_xfs_dqtobp_read(dqp);464 465	/*466	 * store the blkno etc so that we don't have to do the467	 * mapping all the time468	 */469	dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);470 471	error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,472			mp->m_quotainfo->qi_dqchunklen, 0, &bp,473			&xfs_dquot_buf_ops);474	if (xfs_metadata_is_sick(error))475		xfs_dquot_mark_sick(dqp);476	if (error) {477		ASSERT(bp == NULL);478		return error;479	}480 481	ASSERT(xfs_buf_islocked(bp));482	xfs_buf_set_ref(bp, XFS_DQUOT_REF);483	*bpp = bp;484 485	return 0;486}487 488/* Allocate and initialize everything we need for an incore dquot. */489STATIC struct xfs_dquot *490xfs_dquot_alloc(491	struct xfs_mount	*mp,492	xfs_dqid_t		id,493	xfs_dqtype_t		type)494{495	struct xfs_dquot	*dqp;496 497	dqp = kmem_cache_zalloc(xfs_dquot_cache, GFP_KERNEL | __GFP_NOFAIL);498 499	dqp->q_type = type;500	dqp->q_id = id;501	dqp->q_mount = mp;502	INIT_LIST_HEAD(&dqp->q_lru);503	mutex_init(&dqp->q_qlock);504	init_waitqueue_head(&dqp->q_pinwait);505	dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;506	/*507	 * Offset of dquot in the (fixed sized) dquot chunk.508	 */509	dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *510			sizeof(struct xfs_dqblk);511 512	/*513	 * Because we want to use a counting completion, complete514	 * the flush completion once to allow a single access to515	 * the flush completion without blocking.516	 */517	init_completion(&dqp->q_flush);518	complete(&dqp->q_flush);519 520	/*521	 * Make sure group quotas have a different lock class than user522	 * quotas.523	 */524	switch (type) {525	case XFS_DQTYPE_USER:526		/* uses the default lock class */527		break;528	case XFS_DQTYPE_GROUP:529		lockdep_set_class(&dqp->q_qlock, &xfs_dquot_group_class);530		break;531	case XFS_DQTYPE_PROJ:532		lockdep_set_class(&dqp->q_qlock, &xfs_dquot_project_class);533		break;534	default:535		ASSERT(0);536		break;537	}538 539	xfs_qm_dquot_logitem_init(dqp);540 541	XFS_STATS_INC(mp, xs_qm_dquot);542	return dqp;543}544 545/* Check the ondisk dquot's id and type match what the incore dquot expects. */546static bool547xfs_dquot_check_type(548	struct xfs_dquot	*dqp,549	struct xfs_disk_dquot	*ddqp)550{551	uint8_t			ddqp_type;552	uint8_t			dqp_type;553 554	ddqp_type = ddqp->d_type & XFS_DQTYPE_REC_MASK;555	dqp_type = xfs_dquot_type(dqp);556 557	if (be32_to_cpu(ddqp->d_id) != dqp->q_id)558		return false;559 560	/*561	 * V5 filesystems always expect an exact type match.  V4 filesystems562	 * expect an exact match for user dquots and for non-root group and563	 * project dquots.564	 */565	if (xfs_has_crc(dqp->q_mount) ||566	    dqp_type == XFS_DQTYPE_USER || dqp->q_id != 0)567		return ddqp_type == dqp_type;568 569	/*570	 * V4 filesystems support either group or project quotas, but not both571	 * at the same time.  The non-user quota file can be switched between572	 * group and project quota uses depending on the mount options, which573	 * means that we can encounter the other type when we try to load quota574	 * defaults.  Quotacheck will soon reset the entire quota file575	 * (including the root dquot) anyway, but don't log scary corruption576	 * reports to dmesg.577	 */578	return ddqp_type == XFS_DQTYPE_GROUP || ddqp_type == XFS_DQTYPE_PROJ;579}580 581/* Copy the in-core quota fields in from the on-disk buffer. */582STATIC int583xfs_dquot_from_disk(584	struct xfs_dquot	*dqp,585	struct xfs_buf		*bp)586{587	struct xfs_dqblk	*dqb = xfs_buf_offset(bp, dqp->q_bufoffset);588	struct xfs_disk_dquot	*ddqp = &dqb->dd_diskdq;589 590	/*591	 * Ensure that we got the type and ID we were looking for.592	 * Everything else was checked by the dquot buffer verifier.593	 */594	if (!xfs_dquot_check_type(dqp, ddqp)) {595		xfs_alert_tag(bp->b_mount, XFS_PTAG_VERIFIER_ERROR,596			  "Metadata corruption detected at %pS, quota %u",597			  __this_address, dqp->q_id);598		xfs_alert(bp->b_mount, "Unmount and run xfs_repair");599		xfs_dquot_mark_sick(dqp);600		return -EFSCORRUPTED;601	}602 603	/* copy everything from disk dquot to the incore dquot */604	dqp->q_type = ddqp->d_type;605	dqp->q_blk.hardlimit = be64_to_cpu(ddqp->d_blk_hardlimit);606	dqp->q_blk.softlimit = be64_to_cpu(ddqp->d_blk_softlimit);607	dqp->q_ino.hardlimit = be64_to_cpu(ddqp->d_ino_hardlimit);608	dqp->q_ino.softlimit = be64_to_cpu(ddqp->d_ino_softlimit);609	dqp->q_rtb.hardlimit = be64_to_cpu(ddqp->d_rtb_hardlimit);610	dqp->q_rtb.softlimit = be64_to_cpu(ddqp->d_rtb_softlimit);611 612	dqp->q_blk.count = be64_to_cpu(ddqp->d_bcount);613	dqp->q_ino.count = be64_to_cpu(ddqp->d_icount);614	dqp->q_rtb.count = be64_to_cpu(ddqp->d_rtbcount);615 616	dqp->q_blk.timer = xfs_dquot_from_disk_ts(ddqp, ddqp->d_btimer);617	dqp->q_ino.timer = xfs_dquot_from_disk_ts(ddqp, ddqp->d_itimer);618	dqp->q_rtb.timer = xfs_dquot_from_disk_ts(ddqp, ddqp->d_rtbtimer);619 620	/*621	 * Reservation counters are defined as reservation plus current usage622	 * to avoid having to add every time.623	 */624	dqp->q_blk.reserved = dqp->q_blk.count;625	dqp->q_ino.reserved = dqp->q_ino.count;626	dqp->q_rtb.reserved = dqp->q_rtb.count;627 628	/* initialize the dquot speculative prealloc thresholds */629	xfs_dquot_set_prealloc_limits(dqp);630	return 0;631}632 633/* Copy the in-core quota fields into the on-disk buffer. */634void635xfs_dquot_to_disk(636	struct xfs_disk_dquot	*ddqp,637	struct xfs_dquot	*dqp)638{639	ddqp->d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);640	ddqp->d_version = XFS_DQUOT_VERSION;641	ddqp->d_type = dqp->q_type;642	ddqp->d_id = cpu_to_be32(dqp->q_id);643	ddqp->d_pad0 = 0;644	ddqp->d_pad = 0;645 646	ddqp->d_blk_hardlimit = cpu_to_be64(dqp->q_blk.hardlimit);647	ddqp->d_blk_softlimit = cpu_to_be64(dqp->q_blk.softlimit);648	ddqp->d_ino_hardlimit = cpu_to_be64(dqp->q_ino.hardlimit);649	ddqp->d_ino_softlimit = cpu_to_be64(dqp->q_ino.softlimit);650	ddqp->d_rtb_hardlimit = cpu_to_be64(dqp->q_rtb.hardlimit);651	ddqp->d_rtb_softlimit = cpu_to_be64(dqp->q_rtb.softlimit);652 653	ddqp->d_bcount = cpu_to_be64(dqp->q_blk.count);654	ddqp->d_icount = cpu_to_be64(dqp->q_ino.count);655	ddqp->d_rtbcount = cpu_to_be64(dqp->q_rtb.count);656 657	ddqp->d_bwarns = 0;658	ddqp->d_iwarns = 0;659	ddqp->d_rtbwarns = 0;660 661	ddqp->d_btimer = xfs_dquot_to_disk_ts(dqp, dqp->q_blk.timer);662	ddqp->d_itimer = xfs_dquot_to_disk_ts(dqp, dqp->q_ino.timer);663	ddqp->d_rtbtimer = xfs_dquot_to_disk_ts(dqp, dqp->q_rtb.timer);664}665 666/*667 * Read in the ondisk dquot using dqtobp() then copy it to an incore version,668 * and release the buffer immediately.  If @can_alloc is true, fill any669 * holes in the on-disk metadata.670 */671static int672xfs_qm_dqread(673	struct xfs_mount	*mp,674	xfs_dqid_t		id,675	xfs_dqtype_t		type,676	bool			can_alloc,677	struct xfs_dquot	**dqpp)678{679	struct xfs_dquot	*dqp;680	struct xfs_buf		*bp;681	int			error;682 683	dqp = xfs_dquot_alloc(mp, id, type);684	trace_xfs_dqread(dqp);685 686	/* Try to read the buffer, allocating if necessary. */687	error = xfs_dquot_disk_read(mp, dqp, &bp);688	if (error == -ENOENT && can_alloc)689		error = xfs_dquot_disk_alloc(dqp, &bp);690	if (error)691		goto err;692 693	/*694	 * At this point we should have a clean locked buffer.  Copy the data695	 * to the incore dquot and release the buffer since the incore dquot696	 * has its own locking protocol so we needn't tie up the buffer any697	 * further.698	 */699	ASSERT(xfs_buf_islocked(bp));700	error = xfs_dquot_from_disk(dqp, bp);701	xfs_buf_relse(bp);702	if (error)703		goto err;704 705	*dqpp = dqp;706	return error;707 708err:709	trace_xfs_dqread_fail(dqp);710	xfs_qm_dqdestroy(dqp);711	*dqpp = NULL;712	return error;713}714 715/*716 * Advance to the next id in the current chunk, or if at the717 * end of the chunk, skip ahead to first id in next allocated chunk718 * using the SEEK_DATA interface.719 */720static int721xfs_dq_get_next_id(722	struct xfs_mount	*mp,723	xfs_dqtype_t		type,724	xfs_dqid_t		*id)725{726	struct xfs_inode	*quotip = xfs_quota_inode(mp, type);727	xfs_dqid_t		next_id = *id + 1; /* simple advance */728	uint			lock_flags;729	struct xfs_bmbt_irec	got;730	struct xfs_iext_cursor	cur;731	xfs_fsblock_t		start;732	int			error = 0;733 734	/* If we'd wrap past the max ID, stop */735	if (next_id < *id)736		return -ENOENT;737 738	/* If new ID is within the current chunk, advancing it sufficed */739	if (next_id % mp->m_quotainfo->qi_dqperchunk) {740		*id = next_id;741		return 0;742	}743 744	/* Nope, next_id is now past the current chunk, so find the next one */745	start = (xfs_fsblock_t)next_id / mp->m_quotainfo->qi_dqperchunk;746 747	lock_flags = xfs_ilock_data_map_shared(quotip);748	error = xfs_iread_extents(NULL, quotip, XFS_DATA_FORK);749	if (error)750		return error;751 752	if (xfs_iext_lookup_extent(quotip, &quotip->i_df, start, &cur, &got)) {753		/* contiguous chunk, bump startoff for the id calculation */754		if (got.br_startoff < start)755			got.br_startoff = start;756		*id = got.br_startoff * mp->m_quotainfo->qi_dqperchunk;757	} else {758		error = -ENOENT;759	}760 761	xfs_iunlock(quotip, lock_flags);762 763	return error;764}765 766/*767 * Look up the dquot in the in-core cache.  If found, the dquot is returned768 * locked and ready to go.769 */770static struct xfs_dquot *771xfs_qm_dqget_cache_lookup(772	struct xfs_mount	*mp,773	struct xfs_quotainfo	*qi,774	struct radix_tree_root	*tree,775	xfs_dqid_t		id)776{777	struct xfs_dquot	*dqp;778 779restart:780	mutex_lock(&qi->qi_tree_lock);781	dqp = radix_tree_lookup(tree, id);782	if (!dqp) {783		mutex_unlock(&qi->qi_tree_lock);784		XFS_STATS_INC(mp, xs_qm_dqcachemisses);785		return NULL;786	}787 788	xfs_dqlock(dqp);789	if (dqp->q_flags & XFS_DQFLAG_FREEING) {790		xfs_dqunlock(dqp);791		mutex_unlock(&qi->qi_tree_lock);792		trace_xfs_dqget_freeing(dqp);793		delay(1);794		goto restart;795	}796 797	dqp->q_nrefs++;798	mutex_unlock(&qi->qi_tree_lock);799 800	trace_xfs_dqget_hit(dqp);801	XFS_STATS_INC(mp, xs_qm_dqcachehits);802	return dqp;803}804 805/*806 * Try to insert a new dquot into the in-core cache.  If an error occurs the807 * caller should throw away the dquot and start over.  Otherwise, the dquot808 * is returned locked (and held by the cache) as if there had been a cache809 * hit.810 *811 * The insert needs to be done under memalloc_nofs context because the radix812 * tree can do memory allocation during insert. The qi->qi_tree_lock is taken in813 * memory reclaim when freeing unused dquots, so we cannot have the radix tree814 * node allocation recursing into filesystem reclaim whilst we hold the815 * qi_tree_lock.816 */817static int818xfs_qm_dqget_cache_insert(819	struct xfs_mount	*mp,820	struct xfs_quotainfo	*qi,821	struct radix_tree_root	*tree,822	xfs_dqid_t		id,823	struct xfs_dquot	*dqp)824{825	unsigned int		nofs_flags;826	int			error;827 828	nofs_flags = memalloc_nofs_save();829	mutex_lock(&qi->qi_tree_lock);830	error = radix_tree_insert(tree, id, dqp);831	if (unlikely(error)) {832		/* Duplicate found!  Caller must try again. */833		trace_xfs_dqget_dup(dqp);834		goto out_unlock;835	}836 837	/* Return a locked dquot to the caller, with a reference taken. */838	xfs_dqlock(dqp);839	dqp->q_nrefs = 1;840	qi->qi_dquots++;841 842out_unlock:843	mutex_unlock(&qi->qi_tree_lock);844	memalloc_nofs_restore(nofs_flags);845	return error;846}847 848/* Check our input parameters. */849static int850xfs_qm_dqget_checks(851	struct xfs_mount	*mp,852	xfs_dqtype_t		type)853{854	switch (type) {855	case XFS_DQTYPE_USER:856		if (!XFS_IS_UQUOTA_ON(mp))857			return -ESRCH;858		return 0;859	case XFS_DQTYPE_GROUP:860		if (!XFS_IS_GQUOTA_ON(mp))861			return -ESRCH;862		return 0;863	case XFS_DQTYPE_PROJ:864		if (!XFS_IS_PQUOTA_ON(mp))865			return -ESRCH;866		return 0;867	default:868		WARN_ON_ONCE(0);869		return -EINVAL;870	}871}872 873/*874 * Given the file system, id, and type (UDQUOT/GDQUOT/PDQUOT), return a875 * locked dquot, doing an allocation (if requested) as needed.876 */877int878xfs_qm_dqget(879	struct xfs_mount	*mp,880	xfs_dqid_t		id,881	xfs_dqtype_t		type,882	bool			can_alloc,883	struct xfs_dquot	**O_dqpp)884{885	struct xfs_quotainfo	*qi = mp->m_quotainfo;886	struct radix_tree_root	*tree = xfs_dquot_tree(qi, type);887	struct xfs_dquot	*dqp;888	int			error;889 890	error = xfs_qm_dqget_checks(mp, type);891	if (error)892		return error;893 894restart:895	dqp = xfs_qm_dqget_cache_lookup(mp, qi, tree, id);896	if (dqp) {897		*O_dqpp = dqp;898		return 0;899	}900 901	error = xfs_qm_dqread(mp, id, type, can_alloc, &dqp);902	if (error)903		return error;904 905	error = xfs_qm_dqget_cache_insert(mp, qi, tree, id, dqp);906	if (error) {907		/*908		 * Duplicate found. Just throw away the new dquot and start909		 * over.910		 */911		xfs_qm_dqdestroy(dqp);912		XFS_STATS_INC(mp, xs_qm_dquot_dups);913		goto restart;914	}915 916	trace_xfs_dqget_miss(dqp);917	*O_dqpp = dqp;918	return 0;919}920 921/*922 * Given a dquot id and type, read and initialize a dquot from the on-disk923 * metadata.  This function is only for use during quota initialization so924 * it ignores the dquot cache assuming that the dquot shrinker isn't set up.925 * The caller is responsible for _qm_dqdestroy'ing the returned dquot.926 */927int928xfs_qm_dqget_uncached(929	struct xfs_mount	*mp,930	xfs_dqid_t		id,931	xfs_dqtype_t		type,932	struct xfs_dquot	**dqpp)933{934	int			error;935 936	error = xfs_qm_dqget_checks(mp, type);937	if (error)938		return error;939 940	return xfs_qm_dqread(mp, id, type, 0, dqpp);941}942 943/* Return the quota id for a given inode and type. */944xfs_dqid_t945xfs_qm_id_for_quotatype(946	struct xfs_inode	*ip,947	xfs_dqtype_t		type)948{949	switch (type) {950	case XFS_DQTYPE_USER:951		return i_uid_read(VFS_I(ip));952	case XFS_DQTYPE_GROUP:953		return i_gid_read(VFS_I(ip));954	case XFS_DQTYPE_PROJ:955		return ip->i_projid;956	}957	ASSERT(0);958	return 0;959}960 961/*962 * Return the dquot for a given inode and type.  If @can_alloc is true, then963 * allocate blocks if needed.  The inode's ILOCK must be held and it must not964 * have already had an inode attached.965 */966int967xfs_qm_dqget_inode(968	struct xfs_inode	*ip,969	xfs_dqtype_t		type,970	bool			can_alloc,971	struct xfs_dquot	**O_dqpp)972{973	struct xfs_mount	*mp = ip->i_mount;974	struct xfs_quotainfo	*qi = mp->m_quotainfo;975	struct radix_tree_root	*tree = xfs_dquot_tree(qi, type);976	struct xfs_dquot	*dqp;977	xfs_dqid_t		id;978	int			error;979 980	error = xfs_qm_dqget_checks(mp, type);981	if (error)982		return error;983 984	xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);985	ASSERT(xfs_inode_dquot(ip, type) == NULL);986 987	id = xfs_qm_id_for_quotatype(ip, type);988 989restart:990	dqp = xfs_qm_dqget_cache_lookup(mp, qi, tree, id);991	if (dqp) {992		*O_dqpp = dqp;993		return 0;994	}995 996	/*997	 * Dquot cache miss. We don't want to keep the inode lock across998	 * a (potential) disk read. Also we don't want to deal with the lock999	 * ordering between quotainode and this inode. OTOH, dropping the inode1000	 * lock here means dealing with a chown that can happen before1001	 * we re-acquire the lock.1002	 */1003	xfs_iunlock(ip, XFS_ILOCK_EXCL);1004	error = xfs_qm_dqread(mp, id, type, can_alloc, &dqp);1005	xfs_ilock(ip, XFS_ILOCK_EXCL);1006	if (error)1007		return error;1008 1009	/*1010	 * A dquot could be attached to this inode by now, since we had1011	 * dropped the ilock.1012	 */1013	if (xfs_this_quota_on(mp, type)) {1014		struct xfs_dquot	*dqp1;1015 1016		dqp1 = xfs_inode_dquot(ip, type);1017		if (dqp1) {1018			xfs_qm_dqdestroy(dqp);1019			dqp = dqp1;1020			xfs_dqlock(dqp);1021			goto dqret;1022		}1023	} else {1024		/* inode stays locked on return */1025		xfs_qm_dqdestroy(dqp);1026		return -ESRCH;1027	}1028 1029	error = xfs_qm_dqget_cache_insert(mp, qi, tree, id, dqp);1030	if (error) {1031		/*1032		 * Duplicate found. Just throw away the new dquot and start1033		 * over.1034		 */1035		xfs_qm_dqdestroy(dqp);1036		XFS_STATS_INC(mp, xs_qm_dquot_dups);1037		goto restart;1038	}1039 1040dqret:1041	xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);1042	trace_xfs_dqget_miss(dqp);1043	*O_dqpp = dqp;1044	return 0;1045}1046 1047/*1048 * Starting at @id and progressing upwards, look for an initialized incore1049 * dquot, lock it, and return it.1050 */1051int1052xfs_qm_dqget_next(1053	struct xfs_mount	*mp,1054	xfs_dqid_t		id,1055	xfs_dqtype_t		type,1056	struct xfs_dquot	**dqpp)1057{1058	struct xfs_dquot	*dqp;1059	int			error = 0;1060 1061	*dqpp = NULL;1062	for (; !error; error = xfs_dq_get_next_id(mp, type, &id)) {1063		error = xfs_qm_dqget(mp, id, type, false, &dqp);1064		if (error == -ENOENT)1065			continue;1066		else if (error != 0)1067			break;1068 1069		if (!XFS_IS_DQUOT_UNINITIALIZED(dqp)) {1070			*dqpp = dqp;1071			return 0;1072		}1073 1074		xfs_qm_dqput(dqp);1075	}1076 1077	return error;1078}1079 1080/*1081 * Release a reference to the dquot (decrement ref-count) and unlock it.1082 *1083 * If there is a group quota attached to this dquot, carefully release that1084 * too without tripping over deadlocks'n'stuff.1085 */1086void1087xfs_qm_dqput(1088	struct xfs_dquot	*dqp)1089{1090	ASSERT(dqp->q_nrefs > 0);1091	ASSERT(XFS_DQ_IS_LOCKED(dqp));1092 1093	trace_xfs_dqput(dqp);1094 1095	if (--dqp->q_nrefs == 0) {1096		struct xfs_quotainfo	*qi = dqp->q_mount->m_quotainfo;1097		trace_xfs_dqput_free(dqp);1098 1099		if (list_lru_add_obj(&qi->qi_lru, &dqp->q_lru))1100			XFS_STATS_INC(dqp->q_mount, xs_qm_dquot_unused);1101	}1102	xfs_dqunlock(dqp);1103}1104 1105/*1106 * Release a dquot. Flush it if dirty, then dqput() it.1107 * dquot must not be locked.1108 */1109void1110xfs_qm_dqrele(1111	struct xfs_dquot	*dqp)1112{1113	if (!dqp)1114		return;1115 1116	trace_xfs_dqrele(dqp);1117 1118	xfs_dqlock(dqp);1119	/*1120	 * We don't care to flush it if the dquot is dirty here.1121	 * That will create stutters that we want to avoid.1122	 * Instead we do a delayed write when we try to reclaim1123	 * a dirty dquot. Also xfs_sync will take part of the burden...1124	 */1125	xfs_qm_dqput(dqp);1126}1127 1128/*1129 * This is the dquot flushing I/O completion routine.  It is called1130 * from interrupt level when the buffer containing the dquot is1131 * flushed to disk.  It is responsible for removing the dquot logitem1132 * from the AIL if it has not been re-logged, and unlocking the dquot's1133 * flush lock. This behavior is very similar to that of inodes..1134 */1135static void1136xfs_qm_dqflush_done(1137	struct xfs_log_item	*lip)1138{1139	struct xfs_dq_logitem	*qip = (struct xfs_dq_logitem *)lip;1140	struct xfs_dquot	*dqp = qip->qli_dquot;1141	struct xfs_ail		*ailp = lip->li_ailp;1142	xfs_lsn_t		tail_lsn;1143 1144	/*1145	 * We only want to pull the item from the AIL if its1146	 * location in the log has not changed since we started the flush.1147	 * Thus, we only bother if the dquot's lsn has1148	 * not changed. First we check the lsn outside the lock1149	 * since it's cheaper, and then we recheck while1150	 * holding the lock before removing the dquot from the AIL.1151	 */1152	if (test_bit(XFS_LI_IN_AIL, &lip->li_flags) &&1153	    ((lip->li_lsn == qip->qli_flush_lsn) ||1154	     test_bit(XFS_LI_FAILED, &lip->li_flags))) {1155 1156		spin_lock(&ailp->ail_lock);1157		xfs_clear_li_failed(lip);1158		if (lip->li_lsn == qip->qli_flush_lsn) {1159			/* xfs_ail_update_finish() drops the AIL lock */1160			tail_lsn = xfs_ail_delete_one(ailp, lip);1161			xfs_ail_update_finish(ailp, tail_lsn);1162		} else {1163			spin_unlock(&ailp->ail_lock);1164		}1165	}1166 1167	/*1168	 * Release the dq's flush lock since we're done with it.1169	 */1170	xfs_dqfunlock(dqp);1171}1172 1173void1174xfs_buf_dquot_iodone(1175	struct xfs_buf		*bp)1176{1177	struct xfs_log_item	*lip, *n;1178 1179	list_for_each_entry_safe(lip, n, &bp->b_li_list, li_bio_list) {1180		list_del_init(&lip->li_bio_list);1181		xfs_qm_dqflush_done(lip);1182	}1183}1184 1185void1186xfs_buf_dquot_io_fail(1187	struct xfs_buf		*bp)1188{1189	struct xfs_log_item	*lip;1190 1191	spin_lock(&bp->b_mount->m_ail->ail_lock);1192	list_for_each_entry(lip, &bp->b_li_list, li_bio_list)1193		xfs_set_li_failed(lip, bp);1194	spin_unlock(&bp->b_mount->m_ail->ail_lock);1195}1196 1197/* Check incore dquot for errors before we flush. */1198static xfs_failaddr_t1199xfs_qm_dqflush_check(1200	struct xfs_dquot	*dqp)1201{1202	xfs_dqtype_t		type = xfs_dquot_type(dqp);1203 1204	if (type != XFS_DQTYPE_USER &&1205	    type != XFS_DQTYPE_GROUP &&1206	    type != XFS_DQTYPE_PROJ)1207		return __this_address;1208 1209	if (dqp->q_id == 0)1210		return NULL;1211 1212	if (dqp->q_blk.softlimit && dqp->q_blk.count > dqp->q_blk.softlimit &&1213	    !dqp->q_blk.timer)1214		return __this_address;1215 1216	if (dqp->q_ino.softlimit && dqp->q_ino.count > dqp->q_ino.softlimit &&1217	    !dqp->q_ino.timer)1218		return __this_address;1219 1220	if (dqp->q_rtb.softlimit && dqp->q_rtb.count > dqp->q_rtb.softlimit &&1221	    !dqp->q_rtb.timer)1222		return __this_address;1223 1224	/* bigtime flag should never be set on root dquots */1225	if (dqp->q_type & XFS_DQTYPE_BIGTIME) {1226		if (!xfs_has_bigtime(dqp->q_mount))1227			return __this_address;1228		if (dqp->q_id == 0)1229			return __this_address;1230	}1231 1232	return NULL;1233}1234 1235/*1236 * Write a modified dquot to disk.1237 * The dquot must be locked and the flush lock too taken by caller.1238 * The flush lock will not be unlocked until the dquot reaches the disk,1239 * but the dquot is free to be unlocked and modified by the caller1240 * in the interim. Dquot is still locked on return. This behavior is1241 * identical to that of inodes.1242 */1243int1244xfs_qm_dqflush(1245	struct xfs_dquot	*dqp,1246	struct xfs_buf		**bpp)1247{1248	struct xfs_mount	*mp = dqp->q_mount;1249	struct xfs_log_item	*lip = &dqp->q_logitem.qli_item;1250	struct xfs_buf		*bp;1251	struct xfs_dqblk	*dqblk;1252	xfs_failaddr_t		fa;1253	int			error;1254 1255	ASSERT(XFS_DQ_IS_LOCKED(dqp));1256	ASSERT(!completion_done(&dqp->q_flush));1257 1258	trace_xfs_dqflush(dqp);1259 1260	*bpp = NULL;1261 1262	xfs_qm_dqunpin_wait(dqp);1263 1264	/*1265	 * Get the buffer containing the on-disk dquot1266	 */1267	error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,1268				   mp->m_quotainfo->qi_dqchunklen, XBF_TRYLOCK,1269				   &bp, &xfs_dquot_buf_ops);1270	if (error == -EAGAIN)1271		goto out_unlock;1272	if (xfs_metadata_is_sick(error))1273		xfs_dquot_mark_sick(dqp);1274	if (error)1275		goto out_abort;1276 1277	fa = xfs_qm_dqflush_check(dqp);1278	if (fa) {1279		xfs_alert(mp, "corrupt dquot ID 0x%x in memory at %pS",1280				dqp->q_id, fa);1281		xfs_buf_relse(bp);1282		xfs_dquot_mark_sick(dqp);1283		error = -EFSCORRUPTED;1284		goto out_abort;1285	}1286 1287	/* Flush the incore dquot to the ondisk buffer. */1288	dqblk = xfs_buf_offset(bp, dqp->q_bufoffset);1289	xfs_dquot_to_disk(&dqblk->dd_diskdq, dqp);1290 1291	/*1292	 * Clear the dirty field and remember the flush lsn for later use.1293	 */1294	dqp->q_flags &= ~XFS_DQFLAG_DIRTY;1295 1296	xfs_trans_ail_copy_lsn(mp->m_ail, &dqp->q_logitem.qli_flush_lsn,1297					&dqp->q_logitem.qli_item.li_lsn);1298 1299	/*1300	 * copy the lsn into the on-disk dquot now while we have the in memory1301	 * dquot here. This can't be done later in the write verifier as we1302	 * can't get access to the log item at that point in time.1303	 *1304	 * We also calculate the CRC here so that the on-disk dquot in the1305	 * buffer always has a valid CRC. This ensures there is no possibility1306	 * of a dquot without an up-to-date CRC getting to disk.1307	 */1308	if (xfs_has_crc(mp)) {1309		dqblk->dd_lsn = cpu_to_be64(dqp->q_logitem.qli_item.li_lsn);1310		xfs_update_cksum((char *)dqblk, sizeof(struct xfs_dqblk),1311				 XFS_DQUOT_CRC_OFF);1312	}1313 1314	/*1315	 * Attach the dquot to the buffer so that we can remove this dquot from1316	 * the AIL and release the flush lock once the dquot is synced to disk.1317	 */1318	bp->b_flags |= _XBF_DQUOTS;1319	list_add_tail(&dqp->q_logitem.qli_item.li_bio_list, &bp->b_li_list);1320 1321	/*1322	 * If the buffer is pinned then push on the log so we won't1323	 * get stuck waiting in the write for too long.1324	 */1325	if (xfs_buf_ispinned(bp)) {1326		trace_xfs_dqflush_force(dqp);1327		xfs_log_force(mp, 0);1328	}1329 1330	trace_xfs_dqflush_done(dqp);1331	*bpp = bp;1332	return 0;1333 1334out_abort:1335	dqp->q_flags &= ~XFS_DQFLAG_DIRTY;1336	xfs_trans_ail_delete(lip, 0);1337	xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);1338out_unlock:1339	xfs_dqfunlock(dqp);1340	return error;1341}1342 1343/*1344 * Lock two xfs_dquot structures.1345 *1346 * To avoid deadlocks we always lock the quota structure with1347 * the lowerd id first.1348 */1349void1350xfs_dqlock2(1351	struct xfs_dquot	*d1,1352	struct xfs_dquot	*d2)1353{1354	if (d1 && d2) {1355		ASSERT(d1 != d2);1356		if (d1->q_id > d2->q_id) {1357			mutex_lock(&d2->q_qlock);1358			mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED);1359		} else {1360			mutex_lock(&d1->q_qlock);1361			mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED);1362		}1363	} else if (d1) {1364		mutex_lock(&d1->q_qlock);1365	} else if (d2) {1366		mutex_lock(&d2->q_qlock);1367	}1368}1369 1370static int1371xfs_dqtrx_cmp(1372	const void		*a,1373	const void		*b)1374{1375	const struct xfs_dqtrx	*qa = a;1376	const struct xfs_dqtrx	*qb = b;1377 1378	if (qa->qt_dquot->q_id > qb->qt_dquot->q_id)1379		return 1;1380	if (qa->qt_dquot->q_id < qb->qt_dquot->q_id)1381		return -1;1382	return 0;1383}1384 1385void1386xfs_dqlockn(1387	struct xfs_dqtrx	*q)1388{1389	unsigned int		i;1390 1391	BUILD_BUG_ON(XFS_QM_TRANS_MAXDQS > MAX_LOCKDEP_SUBCLASSES);1392 1393	/* Sort in order of dquot id, do not allow duplicates */1394	for (i = 0; i < XFS_QM_TRANS_MAXDQS && q[i].qt_dquot != NULL; i++) {1395		unsigned int	j;1396 1397		for (j = 0; j < i; j++)1398			ASSERT(q[i].qt_dquot != q[j].qt_dquot);1399	}1400	if (i == 0)1401		return;1402 1403	sort(q, i, sizeof(struct xfs_dqtrx), xfs_dqtrx_cmp, NULL);1404 1405	mutex_lock(&q[0].qt_dquot->q_qlock);1406	for (i = 1; i < XFS_QM_TRANS_MAXDQS && q[i].qt_dquot != NULL; i++)1407		mutex_lock_nested(&q[i].qt_dquot->q_qlock,1408				XFS_QLOCK_NESTED + i - 1);1409}1410 1411int __init1412xfs_qm_init(void)1413{1414	xfs_dquot_cache = kmem_cache_create("xfs_dquot",1415					  sizeof(struct xfs_dquot),1416					  0, 0, NULL);1417	if (!xfs_dquot_cache)1418		goto out;1419 1420	xfs_dqtrx_cache = kmem_cache_create("xfs_dqtrx",1421					     sizeof(struct xfs_dquot_acct),1422					     0, 0, NULL);1423	if (!xfs_dqtrx_cache)1424		goto out_free_dquot_cache;1425 1426	return 0;1427 1428out_free_dquot_cache:1429	kmem_cache_destroy(xfs_dquot_cache);1430out:1431	return -ENOMEM;1432}1433 1434void1435xfs_qm_exit(void)1436{1437	kmem_cache_destroy(xfs_dqtrx_cache);1438	kmem_cache_destroy(xfs_dquot_cache);1439}1440