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-rw-r--r--fs/xfs/xfs_dquot.c1454
1 files changed, 1454 insertions, 0 deletions
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
new file mode 100644
index 000000000000..db62959bed13
--- /dev/null
+++ b/fs/xfs/xfs_dquot.c
@@ -0,0 +1,1454 @@
+/*
+ * Copyright (c) 2000-2003 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_bit.h"
+#include "xfs_log.h"
+#include "xfs_inum.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_alloc.h"
+#include "xfs_quota.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_inode.h"
+#include "xfs_bmap.h"
+#include "xfs_rtalloc.h"
+#include "xfs_error.h"
+#include "xfs_itable.h"
+#include "xfs_attr.h"
+#include "xfs_buf_item.h"
+#include "xfs_trans_space.h"
+#include "xfs_trans_priv.h"
+#include "xfs_qm.h"
+#include "xfs_trace.h"
+
+
+/*
+ LOCK ORDER
+
+ inode lock (ilock)
+ dquot hash-chain lock (hashlock)
+ xqm dquot freelist lock (freelistlock
+ mount's dquot list lock (mplistlock)
+ user dquot lock - lock ordering among dquots is based on the uid or gid
+ group dquot lock - similar to udquots. Between the two dquots, the udquot
+ has to be locked first.
+ pin lock - the dquot lock must be held to take this lock.
+ flush lock - ditto.
+*/
+
+#ifdef DEBUG
+xfs_buftarg_t *xfs_dqerror_target;
+int xfs_do_dqerror;
+int xfs_dqreq_num;
+int xfs_dqerror_mod = 33;
+#endif
+
+static struct lock_class_key xfs_dquot_other_class;
+
+/*
+ * Allocate and initialize a dquot. We don't always allocate fresh memory;
+ * we try to reclaim a free dquot if the number of incore dquots are above
+ * a threshold.
+ * The only field inside the core that gets initialized at this point
+ * is the d_id field. The idea is to fill in the entire q_core
+ * when we read in the on disk dquot.
+ */
+STATIC xfs_dquot_t *
+xfs_qm_dqinit(
+ xfs_mount_t *mp,
+ xfs_dqid_t id,
+ uint type)
+{
+ xfs_dquot_t *dqp;
+ boolean_t brandnewdquot;
+
+ brandnewdquot = xfs_qm_dqalloc_incore(&dqp);
+ dqp->dq_flags = type;
+ dqp->q_core.d_id = cpu_to_be32(id);
+ dqp->q_mount = mp;
+
+ /*
+ * No need to re-initialize these if this is a reclaimed dquot.
+ */
+ if (brandnewdquot) {
+ INIT_LIST_HEAD(&dqp->q_freelist);
+ mutex_init(&dqp->q_qlock);
+ init_waitqueue_head(&dqp->q_pinwait);
+
+ /*
+ * Because we want to use a counting completion, complete
+ * the flush completion once to allow a single access to
+ * the flush completion without blocking.
+ */
+ init_completion(&dqp->q_flush);
+ complete(&dqp->q_flush);
+
+ trace_xfs_dqinit(dqp);
+ } else {
+ /*
+ * Only the q_core portion was zeroed in dqreclaim_one().
+ * So, we need to reset others.
+ */
+ dqp->q_nrefs = 0;
+ dqp->q_blkno = 0;
+ INIT_LIST_HEAD(&dqp->q_mplist);
+ INIT_LIST_HEAD(&dqp->q_hashlist);
+ dqp->q_bufoffset = 0;
+ dqp->q_fileoffset = 0;
+ dqp->q_transp = NULL;
+ dqp->q_gdquot = NULL;
+ dqp->q_res_bcount = 0;
+ dqp->q_res_icount = 0;
+ dqp->q_res_rtbcount = 0;
+ atomic_set(&dqp->q_pincount, 0);
+ dqp->q_hash = NULL;
+ ASSERT(list_empty(&dqp->q_freelist));
+
+ trace_xfs_dqreuse(dqp);
+ }
+
+ /*
+ * In either case we need to make sure group quotas have a different
+ * lock class than user quotas, to make sure lockdep knows we can
+ * locks of one of each at the same time.
+ */
+ if (!(type & XFS_DQ_USER))
+ lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
+
+ /*
+ * log item gets initialized later
+ */
+ return (dqp);
+}
+
+/*
+ * This is called to free all the memory associated with a dquot
+ */
+void
+xfs_qm_dqdestroy(
+ xfs_dquot_t *dqp)
+{
+ ASSERT(list_empty(&dqp->q_freelist));
+
+ mutex_destroy(&dqp->q_qlock);
+ kmem_zone_free(xfs_Gqm->qm_dqzone, dqp);
+
+ atomic_dec(&xfs_Gqm->qm_totaldquots);
+}
+
+/*
+ * This is what a 'fresh' dquot inside a dquot chunk looks like on disk.
+ */
+STATIC void
+xfs_qm_dqinit_core(
+ xfs_dqid_t id,
+ uint type,
+ xfs_dqblk_t *d)
+{
+ /*
+ * Caller has zero'd the entire dquot 'chunk' already.
+ */
+ d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
+ d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
+ d->dd_diskdq.d_id = cpu_to_be32(id);
+ d->dd_diskdq.d_flags = type;
+}
+
+/*
+ * If default limits are in force, push them into the dquot now.
+ * We overwrite the dquot limits only if they are zero and this
+ * is not the root dquot.
+ */
+void
+xfs_qm_adjust_dqlimits(
+ xfs_mount_t *mp,
+ xfs_disk_dquot_t *d)
+{
+ xfs_quotainfo_t *q = mp->m_quotainfo;
+
+ ASSERT(d->d_id);
+
+ if (q->qi_bsoftlimit && !d->d_blk_softlimit)
+ d->d_blk_softlimit = cpu_to_be64(q->qi_bsoftlimit);
+ if (q->qi_bhardlimit && !d->d_blk_hardlimit)
+ d->d_blk_hardlimit = cpu_to_be64(q->qi_bhardlimit);
+ if (q->qi_isoftlimit && !d->d_ino_softlimit)
+ d->d_ino_softlimit = cpu_to_be64(q->qi_isoftlimit);
+ if (q->qi_ihardlimit && !d->d_ino_hardlimit)
+ d->d_ino_hardlimit = cpu_to_be64(q->qi_ihardlimit);
+ if (q->qi_rtbsoftlimit && !d->d_rtb_softlimit)
+ d->d_rtb_softlimit = cpu_to_be64(q->qi_rtbsoftlimit);
+ if (q->qi_rtbhardlimit && !d->d_rtb_hardlimit)
+ d->d_rtb_hardlimit = cpu_to_be64(q->qi_rtbhardlimit);
+}
+
+/*
+ * Check the limits and timers of a dquot and start or reset timers
+ * if necessary.
+ * This gets called even when quota enforcement is OFF, which makes our
+ * life a little less complicated. (We just don't reject any quota
+ * reservations in that case, when enforcement is off).
+ * We also return 0 as the values of the timers in Q_GETQUOTA calls, when
+ * enforcement's off.
+ * In contrast, warnings are a little different in that they don't
+ * 'automatically' get started when limits get exceeded. They do
+ * get reset to zero, however, when we find the count to be under
+ * the soft limit (they are only ever set non-zero via userspace).
+ */
+void
+xfs_qm_adjust_dqtimers(
+ xfs_mount_t *mp,
+ xfs_disk_dquot_t *d)
+{
+ ASSERT(d->d_id);
+
+#ifdef DEBUG
+ if (d->d_blk_hardlimit)
+ ASSERT(be64_to_cpu(d->d_blk_softlimit) <=
+ be64_to_cpu(d->d_blk_hardlimit));
+ if (d->d_ino_hardlimit)
+ ASSERT(be64_to_cpu(d->d_ino_softlimit) <=
+ be64_to_cpu(d->d_ino_hardlimit));
+ if (d->d_rtb_hardlimit)
+ ASSERT(be64_to_cpu(d->d_rtb_softlimit) <=
+ be64_to_cpu(d->d_rtb_hardlimit));
+#endif
+
+ if (!d->d_btimer) {
+ if ((d->d_blk_softlimit &&
+ (be64_to_cpu(d->d_bcount) >=
+ be64_to_cpu(d->d_blk_softlimit))) ||
+ (d->d_blk_hardlimit &&
+ (be64_to_cpu(d->d_bcount) >=
+ be64_to_cpu(d->d_blk_hardlimit)))) {
+ d->d_btimer = cpu_to_be32(get_seconds() +
+ mp->m_quotainfo->qi_btimelimit);
+ } else {
+ d->d_bwarns = 0;
+ }
+ } else {
+ if ((!d->d_blk_softlimit ||
+ (be64_to_cpu(d->d_bcount) <
+ be64_to_cpu(d->d_blk_softlimit))) &&
+ (!d->d_blk_hardlimit ||
+ (be64_to_cpu(d->d_bcount) <
+ be64_to_cpu(d->d_blk_hardlimit)))) {
+ d->d_btimer = 0;
+ }
+ }
+
+ if (!d->d_itimer) {
+ if ((d->d_ino_softlimit &&
+ (be64_to_cpu(d->d_icount) >=
+ be64_to_cpu(d->d_ino_softlimit))) ||
+ (d->d_ino_hardlimit &&
+ (be64_to_cpu(d->d_icount) >=
+ be64_to_cpu(d->d_ino_hardlimit)))) {
+ d->d_itimer = cpu_to_be32(get_seconds() +
+ mp->m_quotainfo->qi_itimelimit);
+ } else {
+ d->d_iwarns = 0;
+ }
+ } else {
+ if ((!d->d_ino_softlimit ||
+ (be64_to_cpu(d->d_icount) <
+ be64_to_cpu(d->d_ino_softlimit))) &&
+ (!d->d_ino_hardlimit ||
+ (be64_to_cpu(d->d_icount) <
+ be64_to_cpu(d->d_ino_hardlimit)))) {
+ d->d_itimer = 0;
+ }
+ }
+
+ if (!d->d_rtbtimer) {
+ if ((d->d_rtb_softlimit &&
+ (be64_to_cpu(d->d_rtbcount) >=
+ be64_to_cpu(d->d_rtb_softlimit))) ||
+ (d->d_rtb_hardlimit &&
+ (be64_to_cpu(d->d_rtbcount) >=
+ be64_to_cpu(d->d_rtb_hardlimit)))) {
+ d->d_rtbtimer = cpu_to_be32(get_seconds() +
+ mp->m_quotainfo->qi_rtbtimelimit);
+ } else {
+ d->d_rtbwarns = 0;
+ }
+ } else {
+ if ((!d->d_rtb_softlimit ||
+ (be64_to_cpu(d->d_rtbcount) <
+ be64_to_cpu(d->d_rtb_softlimit))) &&
+ (!d->d_rtb_hardlimit ||
+ (be64_to_cpu(d->d_rtbcount) <
+ be64_to_cpu(d->d_rtb_hardlimit)))) {
+ d->d_rtbtimer = 0;
+ }
+ }
+}
+
+/*
+ * initialize a buffer full of dquots and log the whole thing
+ */
+STATIC void
+xfs_qm_init_dquot_blk(
+ xfs_trans_t *tp,
+ xfs_mount_t *mp,
+ xfs_dqid_t id,
+ uint type,
+ xfs_buf_t *bp)
+{
+ struct xfs_quotainfo *q = mp->m_quotainfo;
+ xfs_dqblk_t *d;
+ int curid, i;
+
+ ASSERT(tp);
+ ASSERT(xfs_buf_islocked(bp));
+
+ d = bp->b_addr;
+
+ /*
+ * ID of the first dquot in the block - id's are zero based.
+ */
+ curid = id - (id % q->qi_dqperchunk);
+ ASSERT(curid >= 0);
+ memset(d, 0, BBTOB(q->qi_dqchunklen));
+ for (i = 0; i < q->qi_dqperchunk; i++, d++, curid++)
+ xfs_qm_dqinit_core(curid, type, d);
+ xfs_trans_dquot_buf(tp, bp,
+ (type & XFS_DQ_USER ? XFS_BLF_UDQUOT_BUF :
+ ((type & XFS_DQ_PROJ) ? XFS_BLF_PDQUOT_BUF :
+ XFS_BLF_GDQUOT_BUF)));
+ xfs_trans_log_buf(tp, bp, 0, BBTOB(q->qi_dqchunklen) - 1);
+}
+
+
+
+/*
+ * Allocate a block and fill it with dquots.
+ * This is called when the bmapi finds a hole.
+ */
+STATIC int
+xfs_qm_dqalloc(
+ xfs_trans_t **tpp,
+ xfs_mount_t *mp,
+ xfs_dquot_t *dqp,
+ xfs_inode_t *quotip,
+ xfs_fileoff_t offset_fsb,
+ xfs_buf_t **O_bpp)
+{
+ xfs_fsblock_t firstblock;
+ xfs_bmap_free_t flist;
+ xfs_bmbt_irec_t map;
+ int nmaps, error, committed;
+ xfs_buf_t *bp;
+ xfs_trans_t *tp = *tpp;
+
+ ASSERT(tp != NULL);
+
+ trace_xfs_dqalloc(dqp);
+
+ /*
+ * Initialize the bmap freelist prior to calling bmapi code.
+ */
+ xfs_bmap_init(&flist, &firstblock);
+ xfs_ilock(quotip, XFS_ILOCK_EXCL);
+ /*
+ * Return if this type of quotas is turned off while we didn't
+ * have an inode lock
+ */
+ if (XFS_IS_THIS_QUOTA_OFF(dqp)) {
+ xfs_iunlock(quotip, XFS_ILOCK_EXCL);
+ return (ESRCH);
+ }
+
+ xfs_trans_ijoin_ref(tp, quotip, XFS_ILOCK_EXCL);
+ nmaps = 1;
+ if ((error = xfs_bmapi(tp, quotip,
+ offset_fsb, XFS_DQUOT_CLUSTER_SIZE_FSB,
+ XFS_BMAPI_METADATA | XFS_BMAPI_WRITE,
+ &firstblock,
+ XFS_QM_DQALLOC_SPACE_RES(mp),
+ &map, &nmaps, &flist))) {
+ goto error0;
+ }
+ ASSERT(map.br_blockcount == XFS_DQUOT_CLUSTER_SIZE_FSB);
+ ASSERT(nmaps == 1);
+ ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
+ (map.br_startblock != HOLESTARTBLOCK));
+
+ /*
+ * Keep track of the blkno to save a lookup later
+ */
+ dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
+
+ /* now we can just get the buffer (there's nothing to read yet) */
+ bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
+ dqp->q_blkno,
+ mp->m_quotainfo->qi_dqchunklen,
+ 0);
+ if (!bp || (error = xfs_buf_geterror(bp)))
+ goto error1;
+ /*
+ * Make a chunk of dquots out of this buffer and log
+ * the entire thing.
+ */
+ xfs_qm_init_dquot_blk(tp, mp, be32_to_cpu(dqp->q_core.d_id),
+ dqp->dq_flags & XFS_DQ_ALLTYPES, bp);
+
+ /*
+ * xfs_bmap_finish() may commit the current transaction and
+ * start a second transaction if the freelist is not empty.
+ *
+ * Since we still want to modify this buffer, we need to
+ * ensure that the buffer is not released on commit of
+ * the first transaction and ensure the buffer is added to the
+ * second transaction.
+ *
+ * If there is only one transaction then don't stop the buffer
+ * from being released when it commits later on.
+ */
+
+ xfs_trans_bhold(tp, bp);
+
+ if ((error = xfs_bmap_finish(tpp, &flist, &committed))) {
+ goto error1;
+ }
+
+ if (committed) {
+ tp = *tpp;
+ xfs_trans_bjoin(tp, bp);
+ } else {
+ xfs_trans_bhold_release(tp, bp);
+ }
+
+ *O_bpp = bp;
+ return 0;
+
+ error1:
+ xfs_bmap_cancel(&flist);
+ error0:
+ xfs_iunlock(quotip, XFS_ILOCK_EXCL);
+
+ return (error);
+}
+
+/*
+ * Maps a dquot to the buffer containing its on-disk version.
+ * This returns a ptr to the buffer containing the on-disk dquot
+ * in the bpp param, and a ptr to the on-disk dquot within that buffer
+ */
+STATIC int
+xfs_qm_dqtobp(
+ xfs_trans_t **tpp,
+ xfs_dquot_t *dqp,
+ xfs_disk_dquot_t **O_ddpp,
+ xfs_buf_t **O_bpp,
+ uint flags)
+{
+ xfs_bmbt_irec_t map;
+ int nmaps = 1, error;
+ xfs_buf_t *bp;
+ xfs_inode_t *quotip = XFS_DQ_TO_QIP(dqp);
+ xfs_mount_t *mp = dqp->q_mount;
+ xfs_disk_dquot_t *ddq;
+ xfs_dqid_t id = be32_to_cpu(dqp->q_core.d_id);
+ xfs_trans_t *tp = (tpp ? *tpp : NULL);
+
+ dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
+
+ xfs_ilock(quotip, XFS_ILOCK_SHARED);
+ if (XFS_IS_THIS_QUOTA_OFF(dqp)) {
+ /*
+ * Return if this type of quotas is turned off while we
+ * didn't have the quota inode lock.
+ */
+ xfs_iunlock(quotip, XFS_ILOCK_SHARED);
+ return ESRCH;
+ }
+
+ /*
+ * Find the block map; no allocations yet
+ */
+ error = xfs_bmapi(NULL, quotip, dqp->q_fileoffset,
+ XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA,
+ NULL, 0, &map, &nmaps, NULL);
+
+ xfs_iunlock(quotip, XFS_ILOCK_SHARED);
+ if (error)
+ return error;
+
+ ASSERT(nmaps == 1);
+ ASSERT(map.br_blockcount == 1);
+
+ /*
+ * Offset of dquot in the (fixed sized) dquot chunk.
+ */
+ dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *
+ sizeof(xfs_dqblk_t);
+
+ ASSERT(map.br_startblock != DELAYSTARTBLOCK);
+ if (map.br_startblock == HOLESTARTBLOCK) {
+ /*
+ * We don't allocate unless we're asked to
+ */
+ if (!(flags & XFS_QMOPT_DQALLOC))
+ return ENOENT;
+
+ ASSERT(tp);
+ error = xfs_qm_dqalloc(tpp, mp, dqp, quotip,
+ dqp->q_fileoffset, &bp);
+ if (error)
+ return error;
+ tp = *tpp;
+ } else {
+ trace_xfs_dqtobp_read(dqp);
+
+ /*
+ * store the blkno etc so that we don't have to do the
+ * mapping all the time
+ */
+ dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
+
+ error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
+ dqp->q_blkno,
+ mp->m_quotainfo->qi_dqchunklen,
+ 0, &bp);
+ if (error || !bp)
+ return XFS_ERROR(error);
+ }
+
+ ASSERT(xfs_buf_islocked(bp));
+
+ /*
+ * calculate the location of the dquot inside the buffer.
+ */
+ ddq = bp->b_addr + dqp->q_bufoffset;
+
+ /*
+ * A simple sanity check in case we got a corrupted dquot...
+ */
+ error = xfs_qm_dqcheck(mp, ddq, id, dqp->dq_flags & XFS_DQ_ALLTYPES,
+ flags & (XFS_QMOPT_DQREPAIR|XFS_QMOPT_DOWARN),
+ "dqtobp");
+ if (error) {
+ if (!(flags & XFS_QMOPT_DQREPAIR)) {
+ xfs_trans_brelse(tp, bp);
+ return XFS_ERROR(EIO);
+ }
+ }
+
+ *O_bpp = bp;
+ *O_ddpp = ddq;
+
+ return (0);
+}
+
+
+/*
+ * Read in the ondisk dquot using dqtobp() then copy it to an incore version,
+ * and release the buffer immediately.
+ *
+ */
+/* ARGSUSED */
+STATIC int
+xfs_qm_dqread(
+ xfs_trans_t **tpp,
+ xfs_dqid_t id,
+ xfs_dquot_t *dqp, /* dquot to get filled in */
+ uint flags)
+{
+ xfs_disk_dquot_t *ddqp;
+ xfs_buf_t *bp;
+ int error;
+ xfs_trans_t *tp;
+
+ ASSERT(tpp);
+
+ trace_xfs_dqread(dqp);
+
+ /*
+ * get a pointer to the on-disk dquot and the buffer containing it
+ * dqp already knows its own type (GROUP/USER).
+ */
+ if ((error = xfs_qm_dqtobp(tpp, dqp, &ddqp, &bp, flags))) {
+ return (error);
+ }
+ tp = *tpp;
+
+ /* copy everything from disk dquot to the incore dquot */
+ memcpy(&dqp->q_core, ddqp, sizeof(xfs_disk_dquot_t));
+ ASSERT(be32_to_cpu(dqp->q_core.d_id) == id);
+ xfs_qm_dquot_logitem_init(dqp);
+
+ /*
+ * Reservation counters are defined as reservation plus current usage
+ * to avoid having to add every time.
+ */
+ dqp->q_res_bcount = be64_to_cpu(ddqp->d_bcount);
+ dqp->q_res_icount = be64_to_cpu(ddqp->d_icount);
+ dqp->q_res_rtbcount = be64_to_cpu(ddqp->d_rtbcount);
+
+ /* Mark the buf so that this will stay incore a little longer */
+ XFS_BUF_SET_VTYPE_REF(bp, B_FS_DQUOT, XFS_DQUOT_REF);
+
+ /*
+ * We got the buffer with a xfs_trans_read_buf() (in dqtobp())
+ * So we need to release with xfs_trans_brelse().
+ * The strategy here is identical to that of inodes; we lock
+ * the dquot in xfs_qm_dqget() before making it accessible to
+ * others. This is because dquots, like inodes, need a good level of
+ * concurrency, and we don't want to take locks on the entire buffers
+ * for dquot accesses.
+ * Note also that the dquot buffer may even be dirty at this point, if
+ * this particular dquot was repaired. We still aren't afraid to
+ * brelse it because we have the changes incore.
+ */
+ ASSERT(xfs_buf_islocked(bp));
+ xfs_trans_brelse(tp, bp);
+
+ return (error);
+}
+
+
+/*
+ * allocate an incore dquot from the kernel heap,
+ * and fill its core with quota information kept on disk.
+ * If XFS_QMOPT_DQALLOC is set, it'll allocate a dquot on disk
+ * if it wasn't already allocated.
+ */
+STATIC int
+xfs_qm_idtodq(
+ xfs_mount_t *mp,
+ xfs_dqid_t id, /* gid or uid, depending on type */
+ uint type, /* UDQUOT or GDQUOT */
+ uint flags, /* DQALLOC, DQREPAIR */
+ xfs_dquot_t **O_dqpp)/* OUT : incore dquot, not locked */
+{
+ xfs_dquot_t *dqp;
+ int error;
+ xfs_trans_t *tp;
+ int cancelflags=0;
+
+ dqp = xfs_qm_dqinit(mp, id, type);
+ tp = NULL;
+ if (flags & XFS_QMOPT_DQALLOC) {
+ tp = xfs_trans_alloc(mp, XFS_TRANS_QM_DQALLOC);
+ error = xfs_trans_reserve(tp, XFS_QM_DQALLOC_SPACE_RES(mp),
+ XFS_WRITE_LOG_RES(mp) +
+ BBTOB(mp->m_quotainfo->qi_dqchunklen) - 1 +
+ 128,
+ 0,
+ XFS_TRANS_PERM_LOG_RES,
+ XFS_WRITE_LOG_COUNT);
+ if (error) {
+ cancelflags = 0;
+ goto error0;
+ }
+ cancelflags = XFS_TRANS_RELEASE_LOG_RES;
+ }
+
+ /*
+ * Read it from disk; xfs_dqread() takes care of
+ * all the necessary initialization of dquot's fields (locks, etc)
+ */
+ if ((error = xfs_qm_dqread(&tp, id, dqp, flags))) {
+ /*
+ * This can happen if quotas got turned off (ESRCH),
+ * or if the dquot didn't exist on disk and we ask to
+ * allocate (ENOENT).
+ */
+ trace_xfs_dqread_fail(dqp);
+ cancelflags |= XFS_TRANS_ABORT;
+ goto error0;
+ }
+ if (tp) {
+ if ((error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES)))
+ goto error1;
+ }
+
+ *O_dqpp = dqp;
+ return (0);
+
+ error0:
+ ASSERT(error);
+ if (tp)
+ xfs_trans_cancel(tp, cancelflags);
+ error1:
+ xfs_qm_dqdestroy(dqp);
+ *O_dqpp = NULL;
+ return (error);
+}
+
+/*
+ * Lookup a dquot in the incore dquot hashtable. We keep two separate
+ * hashtables for user and group dquots; and, these are global tables
+ * inside the XQM, not per-filesystem tables.
+ * The hash chain must be locked by caller, and it is left locked
+ * on return. Returning dquot is locked.
+ */
+STATIC int
+xfs_qm_dqlookup(
+ xfs_mount_t *mp,
+ xfs_dqid_t id,
+ xfs_dqhash_t *qh,
+ xfs_dquot_t **O_dqpp)
+{
+ xfs_dquot_t *dqp;
+ uint flist_locked;
+
+ ASSERT(mutex_is_locked(&qh->qh_lock));
+
+ flist_locked = B_FALSE;
+
+ /*
+ * Traverse the hashchain looking for a match
+ */
+ list_for_each_entry(dqp, &qh->qh_list, q_hashlist) {
+ /*
+ * We already have the hashlock. We don't need the
+ * dqlock to look at the id field of the dquot, since the
+ * id can't be modified without the hashlock anyway.
+ */
+ if (be32_to_cpu(dqp->q_core.d_id) == id && dqp->q_mount == mp) {
+ trace_xfs_dqlookup_found(dqp);
+
+ /*
+ * All in core dquots must be on the dqlist of mp
+ */
+ ASSERT(!list_empty(&dqp->q_mplist));
+
+ xfs_dqlock(dqp);
+ if (dqp->q_nrefs == 0) {
+ ASSERT(!list_empty(&dqp->q_freelist));
+ if (!mutex_trylock(&xfs_Gqm->qm_dqfrlist_lock)) {
+ trace_xfs_dqlookup_want(dqp);
+
+ /*
+ * We may have raced with dqreclaim_one()
+ * (and lost). So, flag that we don't
+ * want the dquot to be reclaimed.
+ */
+ dqp->dq_flags |= XFS_DQ_WANT;
+ xfs_dqunlock(dqp);
+ mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
+ xfs_dqlock(dqp);
+ dqp->dq_flags &= ~(XFS_DQ_WANT);
+ }
+ flist_locked = B_TRUE;
+ }
+
+ /*
+ * id couldn't have changed; we had the hashlock all
+ * along
+ */
+ ASSERT(be32_to_cpu(dqp->q_core.d_id) == id);
+
+ if (flist_locked) {
+ if (dqp->q_nrefs != 0) {
+ mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+ flist_locked = B_FALSE;
+ } else {
+ /* take it off the freelist */
+ trace_xfs_dqlookup_freelist(dqp);
+ list_del_init(&dqp->q_freelist);
+ xfs_Gqm->qm_dqfrlist_cnt--;
+ }
+ }
+
+ XFS_DQHOLD(dqp);
+
+ if (flist_locked)
+ mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+ /*
+ * move the dquot to the front of the hashchain
+ */
+ ASSERT(mutex_is_locked(&qh->qh_lock));
+ list_move(&dqp->q_hashlist, &qh->qh_list);
+ trace_xfs_dqlookup_done(dqp);
+ *O_dqpp = dqp;
+ return 0;
+ }
+ }
+
+ *O_dqpp = NULL;
+ ASSERT(mutex_is_locked(&qh->qh_lock));
+ return (1);
+}
+
+/*
+ * Given the file system, inode OR id, and type (UDQUOT/GDQUOT), return a
+ * a locked dquot, doing an allocation (if requested) as needed.
+ * When both an inode and an id are given, the inode's id takes precedence.
+ * That is, if the id changes while we don't hold the ilock inside this
+ * function, the new dquot is returned, not necessarily the one requested
+ * in the id argument.
+ */
+int
+xfs_qm_dqget(
+ xfs_mount_t *mp,
+ xfs_inode_t *ip, /* locked inode (optional) */
+ xfs_dqid_t id, /* uid/projid/gid depending on type */
+ uint type, /* XFS_DQ_USER/XFS_DQ_PROJ/XFS_DQ_GROUP */
+ uint flags, /* DQALLOC, DQSUSER, DQREPAIR, DOWARN */
+ xfs_dquot_t **O_dqpp) /* OUT : locked incore dquot */
+{
+ xfs_dquot_t *dqp;
+ xfs_dqhash_t *h;
+ uint version;
+ int error;
+
+ ASSERT(XFS_IS_QUOTA_RUNNING(mp));
+ if ((! XFS_IS_UQUOTA_ON(mp) && type == XFS_DQ_USER) ||
+ (! XFS_IS_PQUOTA_ON(mp) && type == XFS_DQ_PROJ) ||
+ (! XFS_IS_GQUOTA_ON(mp) && type == XFS_DQ_GROUP)) {
+ return (ESRCH);
+ }
+ h = XFS_DQ_HASH(mp, id, type);
+
+#ifdef DEBUG
+ if (xfs_do_dqerror) {
+ if ((xfs_dqerror_target == mp->m_ddev_targp) &&
+ (xfs_dqreq_num++ % xfs_dqerror_mod) == 0) {
+ xfs_debug(mp, "Returning error in dqget");
+ return (EIO);
+ }
+ }
+#endif
+
+ again:
+
+#ifdef DEBUG
+ ASSERT(type == XFS_DQ_USER ||
+ type == XFS_DQ_PROJ ||
+ type == XFS_DQ_GROUP);
+ if (ip) {
+ ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+ if (type == XFS_DQ_USER)
+ ASSERT(ip->i_udquot == NULL);
+ else
+ ASSERT(ip->i_gdquot == NULL);
+ }
+#endif
+ mutex_lock(&h->qh_lock);
+
+ /*
+ * Look in the cache (hashtable).
+ * The chain is kept locked during lookup.
+ */
+ if (xfs_qm_dqlookup(mp, id, h, O_dqpp) == 0) {
+ XQM_STATS_INC(xqmstats.xs_qm_dqcachehits);
+ /*
+ * The dquot was found, moved to the front of the chain,
+ * taken off the freelist if it was on it, and locked
+ * at this point. Just unlock the hashchain and return.
+ */
+ ASSERT(*O_dqpp);
+ ASSERT(XFS_DQ_IS_LOCKED(*O_dqpp));
+ mutex_unlock(&h->qh_lock);
+ trace_xfs_dqget_hit(*O_dqpp);
+ return (0); /* success */
+ }
+ XQM_STATS_INC(xqmstats.xs_qm_dqcachemisses);
+
+ /*
+ * Dquot cache miss. We don't want to keep the inode lock across
+ * a (potential) disk read. Also we don't want to deal with the lock
+ * ordering between quotainode and this inode. OTOH, dropping the inode
+ * lock here means dealing with a chown that can happen before
+ * we re-acquire the lock.
+ */
+ if (ip)
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ /*
+ * Save the hashchain version stamp, and unlock the chain, so that
+ * we don't keep the lock across a disk read
+ */
+ version = h->qh_version;
+ mutex_unlock(&h->qh_lock);
+
+ /*
+ * Allocate the dquot on the kernel heap, and read the ondisk
+ * portion off the disk. Also, do all the necessary initialization
+ * This can return ENOENT if dquot didn't exist on disk and we didn't
+ * ask it to allocate; ESRCH if quotas got turned off suddenly.
+ */
+ if ((error = xfs_qm_idtodq(mp, id, type,
+ flags & (XFS_QMOPT_DQALLOC|XFS_QMOPT_DQREPAIR|
+ XFS_QMOPT_DOWARN),
+ &dqp))) {
+ if (ip)
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ return (error);
+ }
+
+ /*
+ * See if this is mount code calling to look at the overall quota limits
+ * which are stored in the id == 0 user or group's dquot.
+ * Since we may not have done a quotacheck by this point, just return
+ * the dquot without attaching it to any hashtables, lists, etc, or even
+ * taking a reference.
+ * The caller must dqdestroy this once done.
+ */
+ if (flags & XFS_QMOPT_DQSUSER) {
+ ASSERT(id == 0);
+ ASSERT(! ip);
+ goto dqret;
+ }
+
+ /*
+ * Dquot lock comes after hashlock in the lock ordering
+ */
+ if (ip) {
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+ /*
+ * A dquot could be attached to this inode by now, since
+ * we had dropped the ilock.
+ */
+ if (type == XFS_DQ_USER) {
+ if (!XFS_IS_UQUOTA_ON(mp)) {
+ /* inode stays locked on return */
+ xfs_qm_dqdestroy(dqp);
+ return XFS_ERROR(ESRCH);
+ }
+ if (ip->i_udquot) {
+ xfs_qm_dqdestroy(dqp);
+ dqp = ip->i_udquot;
+ xfs_dqlock(dqp);
+ goto dqret;
+ }
+ } else {
+ if (!XFS_IS_OQUOTA_ON(mp)) {
+ /* inode stays locked on return */
+ xfs_qm_dqdestroy(dqp);
+ return XFS_ERROR(ESRCH);
+ }
+ if (ip->i_gdquot) {
+ xfs_qm_dqdestroy(dqp);
+ dqp = ip->i_gdquot;
+ xfs_dqlock(dqp);
+ goto dqret;
+ }
+ }
+ }
+
+ /*
+ * Hashlock comes after ilock in lock order
+ */
+ mutex_lock(&h->qh_lock);
+ if (version != h->qh_version) {
+ xfs_dquot_t *tmpdqp;
+ /*
+ * Now, see if somebody else put the dquot in the
+ * hashtable before us. This can happen because we didn't
+ * keep the hashchain lock. We don't have to worry about
+ * lock order between the two dquots here since dqp isn't
+ * on any findable lists yet.
+ */
+ if (xfs_qm_dqlookup(mp, id, h, &tmpdqp) == 0) {
+ /*
+ * Duplicate found. Just throw away the new dquot
+ * and start over.
+ */
+ xfs_qm_dqput(tmpdqp);
+ mutex_unlock(&h->qh_lock);
+ xfs_qm_dqdestroy(dqp);
+ XQM_STATS_INC(xqmstats.xs_qm_dquot_dups);
+ goto again;
+ }
+ }
+
+ /*
+ * Put the dquot at the beginning of the hash-chain and mp's list
+ * LOCK ORDER: hashlock, freelistlock, mplistlock, udqlock, gdqlock ..
+ */
+ ASSERT(mutex_is_locked(&h->qh_lock));
+ dqp->q_hash = h;
+ list_add(&dqp->q_hashlist, &h->qh_list);
+ h->qh_version++;
+
+ /*
+ * Attach this dquot to this filesystem's list of all dquots,
+ * kept inside the mount structure in m_quotainfo field
+ */
+ mutex_lock(&mp->m_quotainfo->qi_dqlist_lock);
+
+ /*
+ * We return a locked dquot to the caller, with a reference taken
+ */
+ xfs_dqlock(dqp);
+ dqp->q_nrefs = 1;
+
+ list_add(&dqp->q_mplist, &mp->m_quotainfo->qi_dqlist);
+ mp->m_quotainfo->qi_dquots++;
+ mutex_unlock(&mp->m_quotainfo->qi_dqlist_lock);
+ mutex_unlock(&h->qh_lock);
+ dqret:
+ ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
+ trace_xfs_dqget_miss(dqp);
+ *O_dqpp = dqp;
+ return (0);
+}
+
+
+/*
+ * Release a reference to the dquot (decrement ref-count)
+ * and unlock it. If there is a group quota attached to this
+ * dquot, carefully release that too without tripping over
+ * deadlocks'n'stuff.
+ */
+void
+xfs_qm_dqput(
+ xfs_dquot_t *dqp)
+{
+ xfs_dquot_t *gdqp;
+
+ ASSERT(dqp->q_nrefs > 0);
+ ASSERT(XFS_DQ_IS_LOCKED(dqp));
+
+ trace_xfs_dqput(dqp);
+
+ if (dqp->q_nrefs != 1) {
+ dqp->q_nrefs--;
+ xfs_dqunlock(dqp);
+ return;
+ }
+
+ /*
+ * drop the dqlock and acquire the freelist and dqlock
+ * in the right order; but try to get it out-of-order first
+ */
+ if (!mutex_trylock(&xfs_Gqm->qm_dqfrlist_lock)) {
+ trace_xfs_dqput_wait(dqp);
+ xfs_dqunlock(dqp);
+ mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
+ xfs_dqlock(dqp);
+ }
+
+ while (1) {
+ gdqp = NULL;
+
+ /* We can't depend on nrefs being == 1 here */
+ if (--dqp->q_nrefs == 0) {
+ trace_xfs_dqput_free(dqp);
+
+ list_add_tail(&dqp->q_freelist, &xfs_Gqm->qm_dqfrlist);
+ xfs_Gqm->qm_dqfrlist_cnt++;
+
+ /*
+ * If we just added a udquot to the freelist, then
+ * we want to release the gdquot reference that
+ * it (probably) has. Otherwise it'll keep the
+ * gdquot from getting reclaimed.
+ */
+ if ((gdqp = dqp->q_gdquot)) {
+ /*
+ * Avoid a recursive dqput call
+ */
+ xfs_dqlock(gdqp);
+ dqp->q_gdquot = NULL;
+ }
+ }
+ xfs_dqunlock(dqp);
+
+ /*
+ * If we had a group quota inside the user quota as a hint,
+ * release it now.
+ */
+ if (! gdqp)
+ break;
+ dqp = gdqp;
+ }
+ mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+}
+
+/*
+ * Release a dquot. Flush it if dirty, then dqput() it.
+ * dquot must not be locked.
+ */
+void
+xfs_qm_dqrele(
+ xfs_dquot_t *dqp)
+{
+ if (!dqp)
+ return;
+
+ trace_xfs_dqrele(dqp);
+
+ xfs_dqlock(dqp);
+ /*
+ * We don't care to flush it if the dquot is dirty here.
+ * That will create stutters that we want to avoid.
+ * Instead we do a delayed write when we try to reclaim
+ * a dirty dquot. Also xfs_sync will take part of the burden...
+ */
+ xfs_qm_dqput(dqp);
+}
+
+/*
+ * This is the dquot flushing I/O completion routine. It is called
+ * from interrupt level when the buffer containing the dquot is
+ * flushed to disk. It is responsible for removing the dquot logitem
+ * from the AIL if it has not been re-logged, and unlocking the dquot's
+ * flush lock. This behavior is very similar to that of inodes..
+ */
+STATIC void
+xfs_qm_dqflush_done(
+ struct xfs_buf *bp,
+ struct xfs_log_item *lip)
+{
+ xfs_dq_logitem_t *qip = (struct xfs_dq_logitem *)lip;
+ xfs_dquot_t *dqp = qip->qli_dquot;
+ struct xfs_ail *ailp = lip->li_ailp;
+
+ /*
+ * We only want to pull the item from the AIL if its
+ * location in the log has not changed since we started the flush.
+ * Thus, we only bother if the dquot's lsn has
+ * not changed. First we check the lsn outside the lock
+ * since it's cheaper, and then we recheck while
+ * holding the lock before removing the dquot from the AIL.
+ */
+ if ((lip->li_flags & XFS_LI_IN_AIL) &&
+ lip->li_lsn == qip->qli_flush_lsn) {
+
+ /* xfs_trans_ail_delete() drops the AIL lock. */
+ spin_lock(&ailp->xa_lock);
+ if (lip->li_lsn == qip->qli_flush_lsn)
+ xfs_trans_ail_delete(ailp, lip);
+ else
+ spin_unlock(&ailp->xa_lock);
+ }
+
+ /*
+ * Release the dq's flush lock since we're done with it.
+ */
+ xfs_dqfunlock(dqp);
+}
+
+/*
+ * Write a modified dquot to disk.
+ * The dquot must be locked and the flush lock too taken by caller.
+ * The flush lock will not be unlocked until the dquot reaches the disk,
+ * but the dquot is free to be unlocked and modified by the caller
+ * in the interim. Dquot is still locked on return. This behavior is
+ * identical to that of inodes.
+ */
+int
+xfs_qm_dqflush(
+ xfs_dquot_t *dqp,
+ uint flags)
+{
+ struct xfs_mount *mp = dqp->q_mount;
+ struct xfs_buf *bp;
+ struct xfs_disk_dquot *ddqp;
+ int error;
+
+ ASSERT(XFS_DQ_IS_LOCKED(dqp));
+ ASSERT(!completion_done(&dqp->q_flush));
+
+ trace_xfs_dqflush(dqp);
+
+ /*
+ * If not dirty, or it's pinned and we are not supposed to block, nada.
+ */
+ if (!XFS_DQ_IS_DIRTY(dqp) ||
+ (!(flags & SYNC_WAIT) && atomic_read(&dqp->q_pincount) > 0)) {
+ xfs_dqfunlock(dqp);
+ return 0;
+ }
+ xfs_qm_dqunpin_wait(dqp);
+
+ /*
+ * This may have been unpinned because the filesystem is shutting
+ * down forcibly. If that's the case we must not write this dquot
+ * to disk, because the log record didn't make it to disk!
+ */
+ if (XFS_FORCED_SHUTDOWN(mp)) {
+ dqp->dq_flags &= ~XFS_DQ_DIRTY;
+ xfs_dqfunlock(dqp);
+ return XFS_ERROR(EIO);
+ }
+
+ /*
+ * Get the buffer containing the on-disk dquot
+ */
+ error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,
+ mp->m_quotainfo->qi_dqchunklen, 0, &bp);
+ if (error) {
+ ASSERT(error != ENOENT);
+ xfs_dqfunlock(dqp);
+ return error;
+ }
+
+ /*
+ * Calculate the location of the dquot inside the buffer.
+ */
+ ddqp = bp->b_addr + dqp->q_bufoffset;
+
+ /*
+ * A simple sanity check in case we got a corrupted dquot..
+ */
+ error = xfs_qm_dqcheck(mp, &dqp->q_core, be32_to_cpu(ddqp->d_id), 0,
+ XFS_QMOPT_DOWARN, "dqflush (incore copy)");
+ if (error) {
+ xfs_buf_relse(bp);
+ xfs_dqfunlock(dqp);
+ xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+ return XFS_ERROR(EIO);
+ }
+
+ /* This is the only portion of data that needs to persist */
+ memcpy(ddqp, &dqp->q_core, sizeof(xfs_disk_dquot_t));
+
+ /*
+ * Clear the dirty field and remember the flush lsn for later use.
+ */
+ dqp->dq_flags &= ~XFS_DQ_DIRTY;
+
+ xfs_trans_ail_copy_lsn(mp->m_ail, &dqp->q_logitem.qli_flush_lsn,
+ &dqp->q_logitem.qli_item.li_lsn);
+
+ /*
+ * Attach an iodone routine so that we can remove this dquot from the
+ * AIL and release the flush lock once the dquot is synced to disk.
+ */
+ xfs_buf_attach_iodone(bp, xfs_qm_dqflush_done,
+ &dqp->q_logitem.qli_item);
+
+ /*
+ * If the buffer is pinned then push on the log so we won't
+ * get stuck waiting in the write for too long.
+ */
+ if (xfs_buf_ispinned(bp)) {
+ trace_xfs_dqflush_force(dqp);
+ xfs_log_force(mp, 0);
+ }
+
+ if (flags & SYNC_WAIT)
+ error = xfs_bwrite(mp, bp);
+ else
+ xfs_bdwrite(mp, bp);
+
+ trace_xfs_dqflush_done(dqp);
+
+ /*
+ * dqp is still locked, but caller is free to unlock it now.
+ */
+ return error;
+
+}
+
+int
+xfs_qm_dqlock_nowait(
+ xfs_dquot_t *dqp)
+{
+ return mutex_trylock(&dqp->q_qlock);
+}
+
+void
+xfs_dqlock(
+ xfs_dquot_t *dqp)
+{
+ mutex_lock(&dqp->q_qlock);
+}
+
+void
+xfs_dqunlock(
+ xfs_dquot_t *dqp)
+{
+ mutex_unlock(&(dqp->q_qlock));
+ if (dqp->q_logitem.qli_dquot == dqp) {
+ /* Once was dqp->q_mount, but might just have been cleared */
+ xfs_trans_unlocked_item(dqp->q_logitem.qli_item.li_ailp,
+ (xfs_log_item_t*)&(dqp->q_logitem));
+ }
+}
+
+
+void
+xfs_dqunlock_nonotify(
+ xfs_dquot_t *dqp)
+{
+ mutex_unlock(&(dqp->q_qlock));
+}
+
+/*
+ * Lock two xfs_dquot structures.
+ *
+ * To avoid deadlocks we always lock the quota structure with
+ * the lowerd id first.
+ */
+void
+xfs_dqlock2(
+ xfs_dquot_t *d1,
+ xfs_dquot_t *d2)
+{
+ if (d1 && d2) {
+ ASSERT(d1 != d2);
+ if (be32_to_cpu(d1->q_core.d_id) >
+ be32_to_cpu(d2->q_core.d_id)) {
+ mutex_lock(&d2->q_qlock);
+ mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED);
+ } else {
+ mutex_lock(&d1->q_qlock);
+ mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED);
+ }
+ } else if (d1) {
+ mutex_lock(&d1->q_qlock);
+ } else if (d2) {
+ mutex_lock(&d2->q_qlock);
+ }
+}
+
+
+/*
+ * Take a dquot out of the mount's dqlist as well as the hashlist.
+ * This is called via unmount as well as quotaoff, and the purge
+ * will always succeed unless there are soft (temp) references
+ * outstanding.
+ *
+ * This returns 0 if it was purged, 1 if it wasn't. It's not an error code
+ * that we're returning! XXXsup - not cool.
+ */
+/* ARGSUSED */
+int
+xfs_qm_dqpurge(
+ xfs_dquot_t *dqp)
+{
+ xfs_dqhash_t *qh = dqp->q_hash;
+ xfs_mount_t *mp = dqp->q_mount;
+
+ ASSERT(mutex_is_locked(&mp->m_quotainfo->qi_dqlist_lock));
+ ASSERT(mutex_is_locked(&dqp->q_hash->qh_lock));
+
+ xfs_dqlock(dqp);
+ /*
+ * We really can't afford to purge a dquot that is
+ * referenced, because these are hard refs.
+ * It shouldn't happen in general because we went thru _all_ inodes in
+ * dqrele_all_inodes before calling this and didn't let the mountlock go.
+ * However it is possible that we have dquots with temporary
+ * references that are not attached to an inode. e.g. see xfs_setattr().
+ */
+ if (dqp->q_nrefs != 0) {
+ xfs_dqunlock(dqp);
+ mutex_unlock(&dqp->q_hash->qh_lock);
+ return (1);
+ }
+
+ ASSERT(!list_empty(&dqp->q_freelist));
+
+ /*
+ * If we're turning off quotas, we have to make sure that, for
+ * example, we don't delete quota disk blocks while dquots are
+ * in the process of getting written to those disk blocks.
+ * This dquot might well be on AIL, and we can't leave it there
+ * if we're turning off quotas. Basically, we need this flush
+ * lock, and are willing to block on it.
+ */
+ if (!xfs_dqflock_nowait(dqp)) {
+ /*
+ * Block on the flush lock after nudging dquot buffer,
+ * if it is incore.
+ */
+ xfs_qm_dqflock_pushbuf_wait(dqp);
+ }
+
+ /*
+ * XXXIf we're turning this type of quotas off, we don't care
+ * about the dirty metadata sitting in this dquot. OTOH, if
+ * we're unmounting, we do care, so we flush it and wait.
+ */
+ if (XFS_DQ_IS_DIRTY(dqp)) {
+ int error;
+
+ /* dqflush unlocks dqflock */
+ /*
+ * Given that dqpurge is a very rare occurrence, it is OK
+ * that we're holding the hashlist and mplist locks
+ * across the disk write. But, ... XXXsup
+ *
+ * We don't care about getting disk errors here. We need
+ * to purge this dquot anyway, so we go ahead regardless.
+ */
+ error = xfs_qm_dqflush(dqp, SYNC_WAIT);
+ if (error)
+ xfs_warn(mp, "%s: dquot %p flush failed",
+ __func__, dqp);
+ xfs_dqflock(dqp);
+ }
+ ASSERT(atomic_read(&dqp->q_pincount) == 0);
+ ASSERT(XFS_FORCED_SHUTDOWN(mp) ||
+ !(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL));
+
+ list_del_init(&dqp->q_hashlist);
+ qh->qh_version++;
+ list_del_init(&dqp->q_mplist);
+ mp->m_quotainfo->qi_dqreclaims++;
+ mp->m_quotainfo->qi_dquots--;
+ /*
+ * XXX Move this to the front of the freelist, if we can get the
+ * freelist lock.
+ */
+ ASSERT(!list_empty(&dqp->q_freelist));
+
+ dqp->q_mount = NULL;
+ dqp->q_hash = NULL;
+ dqp->dq_flags = XFS_DQ_INACTIVE;
+ memset(&dqp->q_core, 0, sizeof(dqp->q_core));
+ xfs_dqfunlock(dqp);
+ xfs_dqunlock(dqp);
+ mutex_unlock(&qh->qh_lock);
+ return (0);
+}
+
+
+/*
+ * Give the buffer a little push if it is incore and
+ * wait on the flush lock.
+ */
+void
+xfs_qm_dqflock_pushbuf_wait(
+ xfs_dquot_t *dqp)
+{
+ xfs_mount_t *mp = dqp->q_mount;
+ xfs_buf_t *bp;
+
+ /*
+ * Check to see if the dquot has been flushed delayed
+ * write. If so, grab its buffer and send it
+ * out immediately. We'll be able to acquire
+ * the flush lock when the I/O completes.
+ */
+ bp = xfs_incore(mp->m_ddev_targp, dqp->q_blkno,
+ mp->m_quotainfo->qi_dqchunklen, XBF_TRYLOCK);
+ if (!bp)
+ goto out_lock;
+
+ if (XFS_BUF_ISDELAYWRITE(bp)) {
+ if (xfs_buf_ispinned(bp))
+ xfs_log_force(mp, 0);
+ xfs_buf_delwri_promote(bp);
+ wake_up_process(bp->b_target->bt_task);
+ }
+ xfs_buf_relse(bp);
+out_lock:
+ xfs_dqflock(dqp);
+}