Revert "xfs: grab dquots without taking the ilock"
[muen/linux.git] / fs / xfs / xfs_dquot.c
1 /*
2  * Copyright (c) 2000-2003 Silicon Graphics, Inc.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write the Free Software Foundation,
16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_format.h"
21 #include "xfs_log_format.h"
22 #include "xfs_shared.h"
23 #include "xfs_trans_resv.h"
24 #include "xfs_bit.h"
25 #include "xfs_mount.h"
26 #include "xfs_defer.h"
27 #include "xfs_inode.h"
28 #include "xfs_bmap.h"
29 #include "xfs_bmap_util.h"
30 #include "xfs_alloc.h"
31 #include "xfs_quota.h"
32 #include "xfs_error.h"
33 #include "xfs_trans.h"
34 #include "xfs_buf_item.h"
35 #include "xfs_trans_space.h"
36 #include "xfs_trans_priv.h"
37 #include "xfs_qm.h"
38 #include "xfs_cksum.h"
39 #include "xfs_trace.h"
40 #include "xfs_log.h"
41 #include "xfs_bmap_btree.h"
42
43 /*
44  * Lock order:
45  *
46  * ip->i_lock
47  *   qi->qi_tree_lock
48  *     dquot->q_qlock (xfs_dqlock() and friends)
49  *       dquot->q_flush (xfs_dqflock() and friends)
50  *       qi->qi_lru_lock
51  *
52  * If two dquots need to be locked the order is user before group/project,
53  * otherwise by the lowest id first, see xfs_dqlock2.
54  */
55
56 #ifdef DEBUG
57 xfs_buftarg_t *xfs_dqerror_target;
58 int xfs_do_dqerror;
59 int xfs_dqreq_num;
60 int xfs_dqerror_mod = 33;
61 #endif
62
63 struct kmem_zone                *xfs_qm_dqtrxzone;
64 static struct kmem_zone         *xfs_qm_dqzone;
65
66 static struct lock_class_key xfs_dquot_group_class;
67 static struct lock_class_key xfs_dquot_project_class;
68
69 /*
70  * This is called to free all the memory associated with a dquot
71  */
72 void
73 xfs_qm_dqdestroy(
74         xfs_dquot_t     *dqp)
75 {
76         ASSERT(list_empty(&dqp->q_lru));
77
78         kmem_free(dqp->q_logitem.qli_item.li_lv_shadow);
79         mutex_destroy(&dqp->q_qlock);
80
81         XFS_STATS_DEC(dqp->q_mount, xs_qm_dquot);
82         kmem_zone_free(xfs_qm_dqzone, dqp);
83 }
84
85 /*
86  * If default limits are in force, push them into the dquot now.
87  * We overwrite the dquot limits only if they are zero and this
88  * is not the root dquot.
89  */
90 void
91 xfs_qm_adjust_dqlimits(
92         struct xfs_mount        *mp,
93         struct xfs_dquot        *dq)
94 {
95         struct xfs_quotainfo    *q = mp->m_quotainfo;
96         struct xfs_disk_dquot   *d = &dq->q_core;
97         struct xfs_def_quota    *defq;
98         int                     prealloc = 0;
99
100         ASSERT(d->d_id);
101         defq = xfs_get_defquota(dq, q);
102
103         if (defq->bsoftlimit && !d->d_blk_softlimit) {
104                 d->d_blk_softlimit = cpu_to_be64(defq->bsoftlimit);
105                 prealloc = 1;
106         }
107         if (defq->bhardlimit && !d->d_blk_hardlimit) {
108                 d->d_blk_hardlimit = cpu_to_be64(defq->bhardlimit);
109                 prealloc = 1;
110         }
111         if (defq->isoftlimit && !d->d_ino_softlimit)
112                 d->d_ino_softlimit = cpu_to_be64(defq->isoftlimit);
113         if (defq->ihardlimit && !d->d_ino_hardlimit)
114                 d->d_ino_hardlimit = cpu_to_be64(defq->ihardlimit);
115         if (defq->rtbsoftlimit && !d->d_rtb_softlimit)
116                 d->d_rtb_softlimit = cpu_to_be64(defq->rtbsoftlimit);
117         if (defq->rtbhardlimit && !d->d_rtb_hardlimit)
118                 d->d_rtb_hardlimit = cpu_to_be64(defq->rtbhardlimit);
119
120         if (prealloc)
121                 xfs_dquot_set_prealloc_limits(dq);
122 }
123
124 /*
125  * Check the limits and timers of a dquot and start or reset timers
126  * if necessary.
127  * This gets called even when quota enforcement is OFF, which makes our
128  * life a little less complicated. (We just don't reject any quota
129  * reservations in that case, when enforcement is off).
130  * We also return 0 as the values of the timers in Q_GETQUOTA calls, when
131  * enforcement's off.
132  * In contrast, warnings are a little different in that they don't
133  * 'automatically' get started when limits get exceeded.  They do
134  * get reset to zero, however, when we find the count to be under
135  * the soft limit (they are only ever set non-zero via userspace).
136  */
137 void
138 xfs_qm_adjust_dqtimers(
139         xfs_mount_t             *mp,
140         xfs_disk_dquot_t        *d)
141 {
142         ASSERT(d->d_id);
143
144 #ifdef DEBUG
145         if (d->d_blk_hardlimit)
146                 ASSERT(be64_to_cpu(d->d_blk_softlimit) <=
147                        be64_to_cpu(d->d_blk_hardlimit));
148         if (d->d_ino_hardlimit)
149                 ASSERT(be64_to_cpu(d->d_ino_softlimit) <=
150                        be64_to_cpu(d->d_ino_hardlimit));
151         if (d->d_rtb_hardlimit)
152                 ASSERT(be64_to_cpu(d->d_rtb_softlimit) <=
153                        be64_to_cpu(d->d_rtb_hardlimit));
154 #endif
155
156         if (!d->d_btimer) {
157                 if ((d->d_blk_softlimit &&
158                      (be64_to_cpu(d->d_bcount) >
159                       be64_to_cpu(d->d_blk_softlimit))) ||
160                     (d->d_blk_hardlimit &&
161                      (be64_to_cpu(d->d_bcount) >
162                       be64_to_cpu(d->d_blk_hardlimit)))) {
163                         d->d_btimer = cpu_to_be32(get_seconds() +
164                                         mp->m_quotainfo->qi_btimelimit);
165                 } else {
166                         d->d_bwarns = 0;
167                 }
168         } else {
169                 if ((!d->d_blk_softlimit ||
170                      (be64_to_cpu(d->d_bcount) <=
171                       be64_to_cpu(d->d_blk_softlimit))) &&
172                     (!d->d_blk_hardlimit ||
173                     (be64_to_cpu(d->d_bcount) <=
174                      be64_to_cpu(d->d_blk_hardlimit)))) {
175                         d->d_btimer = 0;
176                 }
177         }
178
179         if (!d->d_itimer) {
180                 if ((d->d_ino_softlimit &&
181                      (be64_to_cpu(d->d_icount) >
182                       be64_to_cpu(d->d_ino_softlimit))) ||
183                     (d->d_ino_hardlimit &&
184                      (be64_to_cpu(d->d_icount) >
185                       be64_to_cpu(d->d_ino_hardlimit)))) {
186                         d->d_itimer = cpu_to_be32(get_seconds() +
187                                         mp->m_quotainfo->qi_itimelimit);
188                 } else {
189                         d->d_iwarns = 0;
190                 }
191         } else {
192                 if ((!d->d_ino_softlimit ||
193                      (be64_to_cpu(d->d_icount) <=
194                       be64_to_cpu(d->d_ino_softlimit)))  &&
195                     (!d->d_ino_hardlimit ||
196                      (be64_to_cpu(d->d_icount) <=
197                       be64_to_cpu(d->d_ino_hardlimit)))) {
198                         d->d_itimer = 0;
199                 }
200         }
201
202         if (!d->d_rtbtimer) {
203                 if ((d->d_rtb_softlimit &&
204                      (be64_to_cpu(d->d_rtbcount) >
205                       be64_to_cpu(d->d_rtb_softlimit))) ||
206                     (d->d_rtb_hardlimit &&
207                      (be64_to_cpu(d->d_rtbcount) >
208                       be64_to_cpu(d->d_rtb_hardlimit)))) {
209                         d->d_rtbtimer = cpu_to_be32(get_seconds() +
210                                         mp->m_quotainfo->qi_rtbtimelimit);
211                 } else {
212                         d->d_rtbwarns = 0;
213                 }
214         } else {
215                 if ((!d->d_rtb_softlimit ||
216                      (be64_to_cpu(d->d_rtbcount) <=
217                       be64_to_cpu(d->d_rtb_softlimit))) &&
218                     (!d->d_rtb_hardlimit ||
219                      (be64_to_cpu(d->d_rtbcount) <=
220                       be64_to_cpu(d->d_rtb_hardlimit)))) {
221                         d->d_rtbtimer = 0;
222                 }
223         }
224 }
225
226 /*
227  * initialize a buffer full of dquots and log the whole thing
228  */
229 STATIC void
230 xfs_qm_init_dquot_blk(
231         xfs_trans_t     *tp,
232         xfs_mount_t     *mp,
233         xfs_dqid_t      id,
234         uint            type,
235         xfs_buf_t       *bp)
236 {
237         struct xfs_quotainfo    *q = mp->m_quotainfo;
238         xfs_dqblk_t     *d;
239         xfs_dqid_t      curid;
240         int             i;
241
242         ASSERT(tp);
243         ASSERT(xfs_buf_islocked(bp));
244
245         d = bp->b_addr;
246
247         /*
248          * ID of the first dquot in the block - id's are zero based.
249          */
250         curid = id - (id % q->qi_dqperchunk);
251         memset(d, 0, BBTOB(q->qi_dqchunklen));
252         for (i = 0; i < q->qi_dqperchunk; i++, d++, curid++) {
253                 d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
254                 d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
255                 d->dd_diskdq.d_id = cpu_to_be32(curid);
256                 d->dd_diskdq.d_flags = type;
257                 if (xfs_sb_version_hascrc(&mp->m_sb)) {
258                         uuid_copy(&d->dd_uuid, &mp->m_sb.sb_meta_uuid);
259                         xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),
260                                          XFS_DQUOT_CRC_OFF);
261                 }
262         }
263
264         xfs_trans_dquot_buf(tp, bp,
265                             (type & XFS_DQ_USER ? XFS_BLF_UDQUOT_BUF :
266                             ((type & XFS_DQ_PROJ) ? XFS_BLF_PDQUOT_BUF :
267                              XFS_BLF_GDQUOT_BUF)));
268         xfs_trans_log_buf(tp, bp, 0, BBTOB(q->qi_dqchunklen) - 1);
269 }
270
271 /*
272  * Initialize the dynamic speculative preallocation thresholds. The lo/hi
273  * watermarks correspond to the soft and hard limits by default. If a soft limit
274  * is not specified, we use 95% of the hard limit.
275  */
276 void
277 xfs_dquot_set_prealloc_limits(struct xfs_dquot *dqp)
278 {
279         uint64_t space;
280
281         dqp->q_prealloc_hi_wmark = be64_to_cpu(dqp->q_core.d_blk_hardlimit);
282         dqp->q_prealloc_lo_wmark = be64_to_cpu(dqp->q_core.d_blk_softlimit);
283         if (!dqp->q_prealloc_lo_wmark) {
284                 dqp->q_prealloc_lo_wmark = dqp->q_prealloc_hi_wmark;
285                 do_div(dqp->q_prealloc_lo_wmark, 100);
286                 dqp->q_prealloc_lo_wmark *= 95;
287         }
288
289         space = dqp->q_prealloc_hi_wmark;
290
291         do_div(space, 100);
292         dqp->q_low_space[XFS_QLOWSP_1_PCNT] = space;
293         dqp->q_low_space[XFS_QLOWSP_3_PCNT] = space * 3;
294         dqp->q_low_space[XFS_QLOWSP_5_PCNT] = space * 5;
295 }
296
297 /*
298  * Allocate a block and fill it with dquots.
299  * This is called when the bmapi finds a hole.
300  */
301 STATIC int
302 xfs_qm_dqalloc(
303         xfs_trans_t     **tpp,
304         xfs_mount_t     *mp,
305         xfs_dquot_t     *dqp,
306         xfs_inode_t     *quotip,
307         xfs_fileoff_t   offset_fsb,
308         xfs_buf_t       **O_bpp)
309 {
310         xfs_fsblock_t   firstblock;
311         struct xfs_defer_ops dfops;
312         xfs_bmbt_irec_t map;
313         int             nmaps, error;
314         xfs_buf_t       *bp;
315         xfs_trans_t     *tp = *tpp;
316
317         ASSERT(tp != NULL);
318
319         trace_xfs_dqalloc(dqp);
320
321         /*
322          * Initialize the bmap freelist prior to calling bmapi code.
323          */
324         xfs_defer_init(&dfops, &firstblock);
325         xfs_ilock(quotip, XFS_ILOCK_EXCL);
326         /*
327          * Return if this type of quotas is turned off while we didn't
328          * have an inode lock
329          */
330         if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
331                 xfs_iunlock(quotip, XFS_ILOCK_EXCL);
332                 return -ESRCH;
333         }
334
335         xfs_trans_ijoin(tp, quotip, XFS_ILOCK_EXCL);
336         nmaps = 1;
337         error = xfs_bmapi_write(tp, quotip, offset_fsb,
338                                 XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA,
339                                 &firstblock, XFS_QM_DQALLOC_SPACE_RES(mp),
340                                 &map, &nmaps, &dfops);
341         if (error)
342                 goto error0;
343         ASSERT(map.br_blockcount == XFS_DQUOT_CLUSTER_SIZE_FSB);
344         ASSERT(nmaps == 1);
345         ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
346                (map.br_startblock != HOLESTARTBLOCK));
347
348         /*
349          * Keep track of the blkno to save a lookup later
350          */
351         dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
352
353         /* now we can just get the buffer (there's nothing to read yet) */
354         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
355                                dqp->q_blkno,
356                                mp->m_quotainfo->qi_dqchunklen,
357                                0);
358         if (!bp) {
359                 error = -ENOMEM;
360                 goto error1;
361         }
362         bp->b_ops = &xfs_dquot_buf_ops;
363
364         /*
365          * Make a chunk of dquots out of this buffer and log
366          * the entire thing.
367          */
368         xfs_qm_init_dquot_blk(tp, mp, be32_to_cpu(dqp->q_core.d_id),
369                               dqp->dq_flags & XFS_DQ_ALLTYPES, bp);
370
371         /*
372          * xfs_defer_finish() may commit the current transaction and
373          * start a second transaction if the freelist is not empty.
374          *
375          * Since we still want to modify this buffer, we need to
376          * ensure that the buffer is not released on commit of
377          * the first transaction and ensure the buffer is added to the
378          * second transaction.
379          *
380          * If there is only one transaction then don't stop the buffer
381          * from being released when it commits later on.
382          */
383
384         xfs_trans_bhold(tp, bp);
385
386         error = xfs_defer_finish(tpp, &dfops, NULL);
387         if (error)
388                 goto error1;
389
390         /* Transaction was committed? */
391         if (*tpp != tp) {
392                 tp = *tpp;
393                 xfs_trans_bjoin(tp, bp);
394         } else {
395                 xfs_trans_bhold_release(tp, bp);
396         }
397
398         *O_bpp = bp;
399         return 0;
400
401 error1:
402         xfs_defer_cancel(&dfops);
403 error0:
404         xfs_iunlock(quotip, XFS_ILOCK_EXCL);
405
406         return error;
407 }
408
409 STATIC int
410 xfs_qm_dqrepair(
411         struct xfs_mount        *mp,
412         struct xfs_trans        *tp,
413         struct xfs_dquot        *dqp,
414         xfs_dqid_t              firstid,
415         struct xfs_buf          **bpp)
416 {
417         int                     error;
418         struct xfs_disk_dquot   *ddq;
419         struct xfs_dqblk        *d;
420         int                     i;
421
422         /*
423          * Read the buffer without verification so we get the corrupted
424          * buffer returned to us. make sure we verify it on write, though.
425          */
426         error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, dqp->q_blkno,
427                                    mp->m_quotainfo->qi_dqchunklen,
428                                    0, bpp, NULL);
429
430         if (error) {
431                 ASSERT(*bpp == NULL);
432                 return error;
433         }
434         (*bpp)->b_ops = &xfs_dquot_buf_ops;
435
436         ASSERT(xfs_buf_islocked(*bpp));
437         d = (struct xfs_dqblk *)(*bpp)->b_addr;
438
439         /* Do the actual repair of dquots in this buffer */
440         for (i = 0; i < mp->m_quotainfo->qi_dqperchunk; i++) {
441                 ddq = &d[i].dd_diskdq;
442                 error = xfs_dqcheck(mp, ddq, firstid + i,
443                                        dqp->dq_flags & XFS_DQ_ALLTYPES,
444                                        XFS_QMOPT_DQREPAIR, "xfs_qm_dqrepair");
445                 if (error) {
446                         /* repair failed, we're screwed */
447                         xfs_trans_brelse(tp, *bpp);
448                         return -EIO;
449                 }
450         }
451
452         return 0;
453 }
454
455 /*
456  * Maps a dquot to the buffer containing its on-disk version.
457  * This returns a ptr to the buffer containing the on-disk dquot
458  * in the bpp param, and a ptr to the on-disk dquot within that buffer
459  */
460 STATIC int
461 xfs_qm_dqtobp(
462         xfs_trans_t             **tpp,
463         xfs_dquot_t             *dqp,
464         xfs_disk_dquot_t        **O_ddpp,
465         xfs_buf_t               **O_bpp,
466         uint                    flags)
467 {
468         struct xfs_bmbt_irec    map;
469         int                     nmaps = 1, error;
470         struct xfs_buf          *bp;
471         struct xfs_inode        *quotip;
472         struct xfs_mount        *mp = dqp->q_mount;
473         xfs_dqid_t              id = be32_to_cpu(dqp->q_core.d_id);
474         struct xfs_trans        *tp = (tpp ? *tpp : NULL);
475         uint                    lock_mode;
476
477         quotip = xfs_quota_inode(dqp->q_mount, dqp->dq_flags);
478         dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
479
480         lock_mode = xfs_ilock_data_map_shared(quotip);
481         if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
482                 /*
483                  * Return if this type of quotas is turned off while we
484                  * didn't have the quota inode lock.
485                  */
486                 xfs_iunlock(quotip, lock_mode);
487                 return -ESRCH;
488         }
489
490         /*
491          * Find the block map; no allocations yet
492          */
493         error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
494                                XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
495
496         xfs_iunlock(quotip, lock_mode);
497         if (error)
498                 return error;
499
500         ASSERT(nmaps == 1);
501         ASSERT(map.br_blockcount == 1);
502
503         /*
504          * Offset of dquot in the (fixed sized) dquot chunk.
505          */
506         dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *
507                 sizeof(xfs_dqblk_t);
508
509         ASSERT(map.br_startblock != DELAYSTARTBLOCK);
510         if (map.br_startblock == HOLESTARTBLOCK) {
511                 /*
512                  * We don't allocate unless we're asked to
513                  */
514                 if (!(flags & XFS_QMOPT_DQALLOC))
515                         return -ENOENT;
516
517                 ASSERT(tp);
518                 error = xfs_qm_dqalloc(tpp, mp, dqp, quotip,
519                                         dqp->q_fileoffset, &bp);
520                 if (error)
521                         return error;
522                 tp = *tpp;
523         } else {
524                 trace_xfs_dqtobp_read(dqp);
525
526                 /*
527                  * store the blkno etc so that we don't have to do the
528                  * mapping all the time
529                  */
530                 dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
531
532                 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
533                                            dqp->q_blkno,
534                                            mp->m_quotainfo->qi_dqchunklen,
535                                            0, &bp, &xfs_dquot_buf_ops);
536
537                 if (error == -EFSCORRUPTED && (flags & XFS_QMOPT_DQREPAIR)) {
538                         xfs_dqid_t firstid = (xfs_dqid_t)map.br_startoff *
539                                                 mp->m_quotainfo->qi_dqperchunk;
540                         ASSERT(bp == NULL);
541                         error = xfs_qm_dqrepair(mp, tp, dqp, firstid, &bp);
542                 }
543
544                 if (error) {
545                         ASSERT(bp == NULL);
546                         return error;
547                 }
548         }
549
550         ASSERT(xfs_buf_islocked(bp));
551         *O_bpp = bp;
552         *O_ddpp = bp->b_addr + dqp->q_bufoffset;
553
554         return 0;
555 }
556
557
558 /*
559  * Read in the ondisk dquot using dqtobp() then copy it to an incore version,
560  * and release the buffer immediately.
561  *
562  * If XFS_QMOPT_DQALLOC is set, allocate a dquot on disk if it needed.
563  */
564 int
565 xfs_qm_dqread(
566         struct xfs_mount        *mp,
567         xfs_dqid_t              id,
568         uint                    type,
569         uint                    flags,
570         struct xfs_dquot        **O_dqpp)
571 {
572         struct xfs_dquot        *dqp;
573         struct xfs_disk_dquot   *ddqp;
574         struct xfs_buf          *bp;
575         struct xfs_trans        *tp = NULL;
576         int                     error;
577
578         dqp = kmem_zone_zalloc(xfs_qm_dqzone, KM_SLEEP);
579
580         dqp->dq_flags = type;
581         dqp->q_core.d_id = cpu_to_be32(id);
582         dqp->q_mount = mp;
583         INIT_LIST_HEAD(&dqp->q_lru);
584         mutex_init(&dqp->q_qlock);
585         init_waitqueue_head(&dqp->q_pinwait);
586
587         /*
588          * Because we want to use a counting completion, complete
589          * the flush completion once to allow a single access to
590          * the flush completion without blocking.
591          */
592         init_completion(&dqp->q_flush);
593         complete(&dqp->q_flush);
594
595         /*
596          * Make sure group quotas have a different lock class than user
597          * quotas.
598          */
599         switch (type) {
600         case XFS_DQ_USER:
601                 /* uses the default lock class */
602                 break;
603         case XFS_DQ_GROUP:
604                 lockdep_set_class(&dqp->q_qlock, &xfs_dquot_group_class);
605                 break;
606         case XFS_DQ_PROJ:
607                 lockdep_set_class(&dqp->q_qlock, &xfs_dquot_project_class);
608                 break;
609         default:
610                 ASSERT(0);
611                 break;
612         }
613
614         XFS_STATS_INC(mp, xs_qm_dquot);
615
616         trace_xfs_dqread(dqp);
617
618         if (flags & XFS_QMOPT_DQALLOC) {
619                 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_dqalloc,
620                                 XFS_QM_DQALLOC_SPACE_RES(mp), 0, 0, &tp);
621                 if (error)
622                         goto error0;
623         }
624
625         /*
626          * get a pointer to the on-disk dquot and the buffer containing it
627          * dqp already knows its own type (GROUP/USER).
628          */
629         error = xfs_qm_dqtobp(&tp, dqp, &ddqp, &bp, flags);
630         if (error) {
631                 /*
632                  * This can happen if quotas got turned off (ESRCH),
633                  * or if the dquot didn't exist on disk and we ask to
634                  * allocate (ENOENT).
635                  */
636                 trace_xfs_dqread_fail(dqp);
637                 goto error1;
638         }
639
640         /* copy everything from disk dquot to the incore dquot */
641         memcpy(&dqp->q_core, ddqp, sizeof(xfs_disk_dquot_t));
642         xfs_qm_dquot_logitem_init(dqp);
643
644         /*
645          * Reservation counters are defined as reservation plus current usage
646          * to avoid having to add every time.
647          */
648         dqp->q_res_bcount = be64_to_cpu(ddqp->d_bcount);
649         dqp->q_res_icount = be64_to_cpu(ddqp->d_icount);
650         dqp->q_res_rtbcount = be64_to_cpu(ddqp->d_rtbcount);
651
652         /* initialize the dquot speculative prealloc thresholds */
653         xfs_dquot_set_prealloc_limits(dqp);
654
655         /* Mark the buf so that this will stay incore a little longer */
656         xfs_buf_set_ref(bp, XFS_DQUOT_REF);
657
658         /*
659          * We got the buffer with a xfs_trans_read_buf() (in dqtobp())
660          * So we need to release with xfs_trans_brelse().
661          * The strategy here is identical to that of inodes; we lock
662          * the dquot in xfs_qm_dqget() before making it accessible to
663          * others. This is because dquots, like inodes, need a good level of
664          * concurrency, and we don't want to take locks on the entire buffers
665          * for dquot accesses.
666          * Note also that the dquot buffer may even be dirty at this point, if
667          * this particular dquot was repaired. We still aren't afraid to
668          * brelse it because we have the changes incore.
669          */
670         ASSERT(xfs_buf_islocked(bp));
671         xfs_trans_brelse(tp, bp);
672
673         if (tp) {
674                 error = xfs_trans_commit(tp);
675                 if (error)
676                         goto error0;
677         }
678
679         *O_dqpp = dqp;
680         return error;
681
682 error1:
683         if (tp)
684                 xfs_trans_cancel(tp);
685 error0:
686         xfs_qm_dqdestroy(dqp);
687         *O_dqpp = NULL;
688         return error;
689 }
690
691 /*
692  * Advance to the next id in the current chunk, or if at the
693  * end of the chunk, skip ahead to first id in next allocated chunk
694  * using the SEEK_DATA interface.
695  */
696 static int
697 xfs_dq_get_next_id(
698         struct xfs_mount        *mp,
699         uint                    type,
700         xfs_dqid_t              *id)
701 {
702         struct xfs_inode        *quotip = xfs_quota_inode(mp, type);
703         xfs_dqid_t              next_id = *id + 1; /* simple advance */
704         uint                    lock_flags;
705         struct xfs_bmbt_irec    got;
706         xfs_extnum_t            idx;
707         xfs_fsblock_t           start;
708         int                     error = 0;
709
710         /* If we'd wrap past the max ID, stop */
711         if (next_id < *id)
712                 return -ENOENT;
713
714         /* If new ID is within the current chunk, advancing it sufficed */
715         if (next_id % mp->m_quotainfo->qi_dqperchunk) {
716                 *id = next_id;
717                 return 0;
718         }
719
720         /* Nope, next_id is now past the current chunk, so find the next one */
721         start = (xfs_fsblock_t)next_id / mp->m_quotainfo->qi_dqperchunk;
722
723         lock_flags = xfs_ilock_data_map_shared(quotip);
724         if (!(quotip->i_df.if_flags & XFS_IFEXTENTS)) {
725                 error = xfs_iread_extents(NULL, quotip, XFS_DATA_FORK);
726                 if (error)
727                         return error;
728         }
729
730         if (xfs_iext_lookup_extent(quotip, &quotip->i_df, start, &idx, &got)) {
731                 /* contiguous chunk, bump startoff for the id calculation */
732                 if (got.br_startoff < start)
733                         got.br_startoff = start;
734                 *id = got.br_startoff * mp->m_quotainfo->qi_dqperchunk;
735         } else {
736                 error = -ENOENT;
737         }
738
739         xfs_iunlock(quotip, lock_flags);
740
741         return error;
742 }
743
744 /*
745  * Given the file system, inode OR id, and type (UDQUOT/GDQUOT), return a
746  * a locked dquot, doing an allocation (if requested) as needed.
747  * When both an inode and an id are given, the inode's id takes precedence.
748  * That is, if the id changes while we don't hold the ilock inside this
749  * function, the new dquot is returned, not necessarily the one requested
750  * in the id argument.
751  */
752 int
753 xfs_qm_dqget(
754         xfs_mount_t     *mp,
755         xfs_inode_t     *ip,      /* locked inode (optional) */
756         xfs_dqid_t      id,       /* uid/projid/gid depending on type */
757         uint            type,     /* XFS_DQ_USER/XFS_DQ_PROJ/XFS_DQ_GROUP */
758         uint            flags,    /* DQALLOC, DQSUSER, DQREPAIR, DOWARN */
759         xfs_dquot_t     **O_dqpp) /* OUT : locked incore dquot */
760 {
761         struct xfs_quotainfo    *qi = mp->m_quotainfo;
762         struct radix_tree_root *tree = xfs_dquot_tree(qi, type);
763         struct xfs_dquot        *dqp;
764         int                     error;
765
766         ASSERT(XFS_IS_QUOTA_RUNNING(mp));
767         if ((! XFS_IS_UQUOTA_ON(mp) && type == XFS_DQ_USER) ||
768             (! XFS_IS_PQUOTA_ON(mp) && type == XFS_DQ_PROJ) ||
769             (! XFS_IS_GQUOTA_ON(mp) && type == XFS_DQ_GROUP)) {
770                 return -ESRCH;
771         }
772
773 #ifdef DEBUG
774         if (xfs_do_dqerror) {
775                 if ((xfs_dqerror_target == mp->m_ddev_targp) &&
776                     (xfs_dqreq_num++ % xfs_dqerror_mod) == 0) {
777                         xfs_debug(mp, "Returning error in dqget");
778                         return -EIO;
779                 }
780         }
781
782         ASSERT(type == XFS_DQ_USER ||
783                type == XFS_DQ_PROJ ||
784                type == XFS_DQ_GROUP);
785         if (ip) {
786                 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
787                 ASSERT(xfs_inode_dquot(ip, type) == NULL);
788         }
789 #endif
790
791 restart:
792         mutex_lock(&qi->qi_tree_lock);
793         dqp = radix_tree_lookup(tree, id);
794         if (dqp) {
795                 xfs_dqlock(dqp);
796                 if (dqp->dq_flags & XFS_DQ_FREEING) {
797                         xfs_dqunlock(dqp);
798                         mutex_unlock(&qi->qi_tree_lock);
799                         trace_xfs_dqget_freeing(dqp);
800                         delay(1);
801                         goto restart;
802                 }
803
804                 /* uninit / unused quota found in radix tree, keep looking  */
805                 if (flags & XFS_QMOPT_DQNEXT) {
806                         if (XFS_IS_DQUOT_UNINITIALIZED(dqp)) {
807                                 xfs_dqunlock(dqp);
808                                 mutex_unlock(&qi->qi_tree_lock);
809                                 error = xfs_dq_get_next_id(mp, type, &id);
810                                 if (error)
811                                         return error;
812                                 goto restart;
813                         }
814                 }
815
816                 dqp->q_nrefs++;
817                 mutex_unlock(&qi->qi_tree_lock);
818
819                 trace_xfs_dqget_hit(dqp);
820                 XFS_STATS_INC(mp, xs_qm_dqcachehits);
821                 *O_dqpp = dqp;
822                 return 0;
823         }
824         mutex_unlock(&qi->qi_tree_lock);
825         XFS_STATS_INC(mp, xs_qm_dqcachemisses);
826
827         /*
828          * Dquot cache miss. We don't want to keep the inode lock across
829          * a (potential) disk read. Also we don't want to deal with the lock
830          * ordering between quotainode and this inode. OTOH, dropping the inode
831          * lock here means dealing with a chown that can happen before
832          * we re-acquire the lock.
833          */
834         if (ip)
835                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
836
837         error = xfs_qm_dqread(mp, id, type, flags, &dqp);
838
839         if (ip)
840                 xfs_ilock(ip, XFS_ILOCK_EXCL);
841
842         /* If we are asked to find next active id, keep looking */
843         if (error == -ENOENT && (flags & XFS_QMOPT_DQNEXT)) {
844                 error = xfs_dq_get_next_id(mp, type, &id);
845                 if (!error)
846                         goto restart;
847         }
848
849         if (error)
850                 return error;
851
852         if (ip) {
853                 /*
854                  * A dquot could be attached to this inode by now, since
855                  * we had dropped the ilock.
856                  */
857                 if (xfs_this_quota_on(mp, type)) {
858                         struct xfs_dquot        *dqp1;
859
860                         dqp1 = xfs_inode_dquot(ip, type);
861                         if (dqp1) {
862                                 xfs_qm_dqdestroy(dqp);
863                                 dqp = dqp1;
864                                 xfs_dqlock(dqp);
865                                 goto dqret;
866                         }
867                 } else {
868                         /* inode stays locked on return */
869                         xfs_qm_dqdestroy(dqp);
870                         return -ESRCH;
871                 }
872         }
873
874         mutex_lock(&qi->qi_tree_lock);
875         error = radix_tree_insert(tree, id, dqp);
876         if (unlikely(error)) {
877                 WARN_ON(error != -EEXIST);
878
879                 /*
880                  * Duplicate found. Just throw away the new dquot and start
881                  * over.
882                  */
883                 mutex_unlock(&qi->qi_tree_lock);
884                 trace_xfs_dqget_dup(dqp);
885                 xfs_qm_dqdestroy(dqp);
886                 XFS_STATS_INC(mp, xs_qm_dquot_dups);
887                 goto restart;
888         }
889
890         /*
891          * We return a locked dquot to the caller, with a reference taken
892          */
893         xfs_dqlock(dqp);
894         dqp->q_nrefs = 1;
895
896         qi->qi_dquots++;
897         mutex_unlock(&qi->qi_tree_lock);
898
899         /* If we are asked to find next active id, keep looking */
900         if (flags & XFS_QMOPT_DQNEXT) {
901                 if (XFS_IS_DQUOT_UNINITIALIZED(dqp)) {
902                         xfs_qm_dqput(dqp);
903                         error = xfs_dq_get_next_id(mp, type, &id);
904                         if (error)
905                                 return error;
906                         goto restart;
907                 }
908         }
909
910  dqret:
911         ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
912         trace_xfs_dqget_miss(dqp);
913         *O_dqpp = dqp;
914         return 0;
915 }
916
917 /*
918  * Release a reference to the dquot (decrement ref-count) and unlock it.
919  *
920  * If there is a group quota attached to this dquot, carefully release that
921  * too without tripping over deadlocks'n'stuff.
922  */
923 void
924 xfs_qm_dqput(
925         struct xfs_dquot        *dqp)
926 {
927         ASSERT(dqp->q_nrefs > 0);
928         ASSERT(XFS_DQ_IS_LOCKED(dqp));
929
930         trace_xfs_dqput(dqp);
931
932         if (--dqp->q_nrefs == 0) {
933                 struct xfs_quotainfo    *qi = dqp->q_mount->m_quotainfo;
934                 trace_xfs_dqput_free(dqp);
935
936                 if (list_lru_add(&qi->qi_lru, &dqp->q_lru))
937                         XFS_STATS_INC(dqp->q_mount, xs_qm_dquot_unused);
938         }
939         xfs_dqunlock(dqp);
940 }
941
942 /*
943  * Release a dquot. Flush it if dirty, then dqput() it.
944  * dquot must not be locked.
945  */
946 void
947 xfs_qm_dqrele(
948         xfs_dquot_t     *dqp)
949 {
950         if (!dqp)
951                 return;
952
953         trace_xfs_dqrele(dqp);
954
955         xfs_dqlock(dqp);
956         /*
957          * We don't care to flush it if the dquot is dirty here.
958          * That will create stutters that we want to avoid.
959          * Instead we do a delayed write when we try to reclaim
960          * a dirty dquot. Also xfs_sync will take part of the burden...
961          */
962         xfs_qm_dqput(dqp);
963 }
964
965 /*
966  * This is the dquot flushing I/O completion routine.  It is called
967  * from interrupt level when the buffer containing the dquot is
968  * flushed to disk.  It is responsible for removing the dquot logitem
969  * from the AIL if it has not been re-logged, and unlocking the dquot's
970  * flush lock. This behavior is very similar to that of inodes..
971  */
972 STATIC void
973 xfs_qm_dqflush_done(
974         struct xfs_buf          *bp,
975         struct xfs_log_item     *lip)
976 {
977         xfs_dq_logitem_t        *qip = (struct xfs_dq_logitem *)lip;
978         xfs_dquot_t             *dqp = qip->qli_dquot;
979         struct xfs_ail          *ailp = lip->li_ailp;
980
981         /*
982          * We only want to pull the item from the AIL if its
983          * location in the log has not changed since we started the flush.
984          * Thus, we only bother if the dquot's lsn has
985          * not changed. First we check the lsn outside the lock
986          * since it's cheaper, and then we recheck while
987          * holding the lock before removing the dquot from the AIL.
988          */
989         if ((lip->li_flags & XFS_LI_IN_AIL) &&
990             lip->li_lsn == qip->qli_flush_lsn) {
991
992                 /* xfs_trans_ail_delete() drops the AIL lock. */
993                 spin_lock(&ailp->xa_lock);
994                 if (lip->li_lsn == qip->qli_flush_lsn)
995                         xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
996                 else
997                         spin_unlock(&ailp->xa_lock);
998         }
999
1000         /*
1001          * Release the dq's flush lock since we're done with it.
1002          */
1003         xfs_dqfunlock(dqp);
1004 }
1005
1006 /*
1007  * Write a modified dquot to disk.
1008  * The dquot must be locked and the flush lock too taken by caller.
1009  * The flush lock will not be unlocked until the dquot reaches the disk,
1010  * but the dquot is free to be unlocked and modified by the caller
1011  * in the interim. Dquot is still locked on return. This behavior is
1012  * identical to that of inodes.
1013  */
1014 int
1015 xfs_qm_dqflush(
1016         struct xfs_dquot        *dqp,
1017         struct xfs_buf          **bpp)
1018 {
1019         struct xfs_mount        *mp = dqp->q_mount;
1020         struct xfs_buf          *bp;
1021         struct xfs_disk_dquot   *ddqp;
1022         int                     error;
1023
1024         ASSERT(XFS_DQ_IS_LOCKED(dqp));
1025         ASSERT(!completion_done(&dqp->q_flush));
1026
1027         trace_xfs_dqflush(dqp);
1028
1029         *bpp = NULL;
1030
1031         xfs_qm_dqunpin_wait(dqp);
1032
1033         /*
1034          * This may have been unpinned because the filesystem is shutting
1035          * down forcibly. If that's the case we must not write this dquot
1036          * to disk, because the log record didn't make it to disk.
1037          *
1038          * We also have to remove the log item from the AIL in this case,
1039          * as we wait for an emptry AIL as part of the unmount process.
1040          */
1041         if (XFS_FORCED_SHUTDOWN(mp)) {
1042                 struct xfs_log_item     *lip = &dqp->q_logitem.qli_item;
1043                 dqp->dq_flags &= ~XFS_DQ_DIRTY;
1044
1045                 xfs_trans_ail_remove(lip, SHUTDOWN_CORRUPT_INCORE);
1046
1047                 error = -EIO;
1048                 goto out_unlock;
1049         }
1050
1051         /*
1052          * Get the buffer containing the on-disk dquot
1053          */
1054         error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,
1055                                    mp->m_quotainfo->qi_dqchunklen, 0, &bp,
1056                                    &xfs_dquot_buf_ops);
1057         if (error)
1058                 goto out_unlock;
1059
1060         /*
1061          * Calculate the location of the dquot inside the buffer.
1062          */
1063         ddqp = bp->b_addr + dqp->q_bufoffset;
1064
1065         /*
1066          * A simple sanity check in case we got a corrupted dquot..
1067          */
1068         error = xfs_dqcheck(mp, &dqp->q_core, be32_to_cpu(ddqp->d_id), 0,
1069                            XFS_QMOPT_DOWARN, "dqflush (incore copy)");
1070         if (error) {
1071                 xfs_buf_relse(bp);
1072                 xfs_dqfunlock(dqp);
1073                 xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
1074                 return -EIO;
1075         }
1076
1077         /* This is the only portion of data that needs to persist */
1078         memcpy(ddqp, &dqp->q_core, sizeof(xfs_disk_dquot_t));
1079
1080         /*
1081          * Clear the dirty field and remember the flush lsn for later use.
1082          */
1083         dqp->dq_flags &= ~XFS_DQ_DIRTY;
1084
1085         xfs_trans_ail_copy_lsn(mp->m_ail, &dqp->q_logitem.qli_flush_lsn,
1086                                         &dqp->q_logitem.qli_item.li_lsn);
1087
1088         /*
1089          * copy the lsn into the on-disk dquot now while we have the in memory
1090          * dquot here. This can't be done later in the write verifier as we
1091          * can't get access to the log item at that point in time.
1092          *
1093          * We also calculate the CRC here so that the on-disk dquot in the
1094          * buffer always has a valid CRC. This ensures there is no possibility
1095          * of a dquot without an up-to-date CRC getting to disk.
1096          */
1097         if (xfs_sb_version_hascrc(&mp->m_sb)) {
1098                 struct xfs_dqblk *dqb = (struct xfs_dqblk *)ddqp;
1099
1100                 dqb->dd_lsn = cpu_to_be64(dqp->q_logitem.qli_item.li_lsn);
1101                 xfs_update_cksum((char *)dqb, sizeof(struct xfs_dqblk),
1102                                  XFS_DQUOT_CRC_OFF);
1103         }
1104
1105         /*
1106          * Attach an iodone routine so that we can remove this dquot from the
1107          * AIL and release the flush lock once the dquot is synced to disk.
1108          */
1109         xfs_buf_attach_iodone(bp, xfs_qm_dqflush_done,
1110                                   &dqp->q_logitem.qli_item);
1111
1112         /*
1113          * If the buffer is pinned then push on the log so we won't
1114          * get stuck waiting in the write for too long.
1115          */
1116         if (xfs_buf_ispinned(bp)) {
1117                 trace_xfs_dqflush_force(dqp);
1118                 xfs_log_force(mp, 0);
1119         }
1120
1121         trace_xfs_dqflush_done(dqp);
1122         *bpp = bp;
1123         return 0;
1124
1125 out_unlock:
1126         xfs_dqfunlock(dqp);
1127         return -EIO;
1128 }
1129
1130 /*
1131  * Lock two xfs_dquot structures.
1132  *
1133  * To avoid deadlocks we always lock the quota structure with
1134  * the lowerd id first.
1135  */
1136 void
1137 xfs_dqlock2(
1138         xfs_dquot_t     *d1,
1139         xfs_dquot_t     *d2)
1140 {
1141         if (d1 && d2) {
1142                 ASSERT(d1 != d2);
1143                 if (be32_to_cpu(d1->q_core.d_id) >
1144                     be32_to_cpu(d2->q_core.d_id)) {
1145                         mutex_lock(&d2->q_qlock);
1146                         mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED);
1147                 } else {
1148                         mutex_lock(&d1->q_qlock);
1149                         mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED);
1150                 }
1151         } else if (d1) {
1152                 mutex_lock(&d1->q_qlock);
1153         } else if (d2) {
1154                 mutex_lock(&d2->q_qlock);
1155         }
1156 }
1157
1158 int __init
1159 xfs_qm_init(void)
1160 {
1161         xfs_qm_dqzone =
1162                 kmem_zone_init(sizeof(struct xfs_dquot), "xfs_dquot");
1163         if (!xfs_qm_dqzone)
1164                 goto out;
1165
1166         xfs_qm_dqtrxzone =
1167                 kmem_zone_init(sizeof(struct xfs_dquot_acct), "xfs_dqtrx");
1168         if (!xfs_qm_dqtrxzone)
1169                 goto out_free_dqzone;
1170
1171         return 0;
1172
1173 out_free_dqzone:
1174         kmem_zone_destroy(xfs_qm_dqzone);
1175 out:
1176         return -ENOMEM;
1177 }
1178
1179 void
1180 xfs_qm_exit(void)
1181 {
1182         kmem_zone_destroy(xfs_qm_dqtrxzone);
1183         kmem_zone_destroy(xfs_qm_dqzone);
1184 }