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xfs_dquot.c
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/*
* 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:
*
* ip->i_lock
* qh->qh_lock
* qi->qi_dqlist_lock
* dquot->q_qlock (xfs_dqlock() and friends)
* dquot->q_flush (xfs_dqflock() and friends)
* xfs_Gqm->qm_dqfrlist_lock
*
* If two dquots need to be locked the order is user before group/project,
* otherwise by the lowest id first, see xfs_dqlock2.
*/
#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;
/*
* 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);
}
/*
* 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++) {
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(curid);
d->dd_diskdq.d_flags = type;
}
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(tp, quotip, XFS_ILOCK_EXCL);
nmaps = 1;
error = xfs_bmapi_write(tp, quotip, offset_fsb,
XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA,
&firstblock, XFS_QM_DQALLOC_SPACE_RES(mp),
&map, &nmaps, &flist);
if (error)
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);
error = xfs_buf_geterror(bp);
if (error)
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_read(quotip, dqp->q_fileoffset,
XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
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.
*
* If XFS_QMOPT_DQALLOC is set, allocate a dquot on disk if it needed.
*/
int
xfs_qm_dqread(
struct xfs_mount *mp,
xfs_dqid_t id,
uint type,
uint flags,
struct xfs_dquot **O_dqpp)
{
struct xfs_dquot *dqp;
struct xfs_disk_dquot *ddqp;
struct xfs_buf *bp;
struct xfs_trans *tp = NULL;
int error;
int cancelflags = 0;
dqp = kmem_zone_zalloc(xfs_Gqm->qm_dqzone, KM_SLEEP);
dqp->dq_flags = type;
dqp->q_core.d_id = cpu_to_be32(id);
dqp->q_mount = mp;
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);
/*
* Make sure group quotas have a different lock class than user
* quotas.
*/
if (!(type & XFS_DQ_USER))
lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
atomic_inc(&xfs_Gqm->qm_totaldquots);
trace_xfs_dqread(dqp);
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) +
/*
* Round the chunklen up to the next multiple
* of 128 (buf log item chunk size)).
*/
BBTOB(mp->m_quotainfo->qi_dqchunklen) - 1 + 128,
0,
XFS_TRANS_PERM_LOG_RES,
XFS_WRITE_LOG_COUNT);
if (error)
goto error1;
cancelflags = XFS_TRANS_RELEASE_LOG_RES;
}
/*
* get a pointer to the on-disk dquot and the buffer containing it
* dqp already knows its own type (GROUP/USER).
*/
error = xfs_qm_dqtobp(&tp, dqp, &ddqp, &bp, flags);
if (error) {
/*
* 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 error1;
}
/* copy everything from disk dquot to the incore dquot */
memcpy(&dqp->q_core, ddqp, sizeof(xfs_disk_dquot_t));
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_ref(bp, 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);
if (tp) {
error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
if (error)
goto error0;
}
*O_dqpp = dqp;
return error;
error1:
if (tp)
xfs_trans_cancel(tp, cancelflags);
error0:
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;
ASSERT(mutex_is_locked(&qh->qh_lock));
/*
* 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)
continue;
trace_xfs_dqlookup_found(dqp);
xfs_dqlock(dqp);
if (dqp->dq_flags & XFS_DQ_FREEING) {
*O_dqpp = NULL;
xfs_dqunlock(dqp);
return -1;
}
dqp->q_nrefs++;
/*
* move the dquot to the front of the hashchain
*/
list_move(&dqp->q_hashlist, &qh->qh_list);
trace_xfs_dqlookup_done(dqp);
*O_dqpp = dqp;
return 0;
}
*O_dqpp = NULL;
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);
}
}
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
restart:
mutex_lock(&h->qh_lock);
/*
* Look in the cache (hashtable).
* The chain is kept locked during lookup.
*/
switch (xfs_qm_dqlookup(mp, id, h, O_dqpp)) {
case -1:
XQM_STATS_INC(xqmstats.xs_qm_dquot_dups);
mutex_unlock(&h->qh_lock);
delay(1);
goto restart;
case 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 */
default:
XQM_STATS_INC(xqmstats.xs_qm_dqcachemisses);
break;
}
/*
* 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);
error = xfs_qm_dqread(mp, id, type, flags, &dqp);
if (ip)
xfs_ilock(ip, XFS_ILOCK_EXCL);
if (error)
return error;
/*
* Dquot lock comes after hashlock in the lock ordering
*/
if (ip) {
/*
* 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.
*/
switch (xfs_qm_dqlookup(mp, id, h, &tmpdqp)) {
case 0:
case -1:
/*
* Duplicate found, either in cache or on its way out.
* Just throw away the new dquot and start over.
*/
if (tmpdqp)
xfs_qm_dqput(tmpdqp);
mutex_unlock(&h->qh_lock);
xfs_qm_dqdestroy(dqp);
XQM_STATS_INC(xqmstats.xs_qm_dquot_dups);
goto restart;
default:
break;
}
}
/*
* 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(
struct xfs_dquot *dqp)
{
struct xfs_dquot *gdqp;
ASSERT(dqp->q_nrefs > 0);
ASSERT(XFS_DQ_IS_LOCKED(dqp));
trace_xfs_dqput(dqp);
recurse:
if (--dqp->q_nrefs > 0) {
xfs_dqunlock(dqp);
return;
}
trace_xfs_dqput_free(dqp);
mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
if (list_empty(&dqp->q_freelist)) {
list_add_tail(&dqp->q_freelist, &xfs_Gqm->qm_dqfrlist);
xfs_Gqm->qm_dqfrlist_cnt++;
}
mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
/*
* 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.
*/
gdqp = dqp->q_gdquot;
if (gdqp) {
xfs_dqlock(gdqp);
dqp->q_gdquot = NULL;
}
xfs_dqunlock(dqp);
/*
* If we had a group quota hint, release it now.
*/
if (gdqp) {
dqp = gdqp;
goto recurse;
}
}
/*
* 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);