/*
* This is called to attempt to lock the dquot associated with this
* dquot log item. Don't sleep on the dquot lock or the flush lock.
* If the flush lock is already held, indicating that the dquot has
* been or is in the process of being flushed, then see if we can
* find the dquot's buffer in the buffer cache without sleeping. If
* we can and it is marked delayed write, then we want to send it out.
* We delay doing so until the push routine, though, to avoid sleeping
* in any device strategy routines.
*/
STATIC uint
xfs_qm_dquot_logitem_trylock(
struct xfs_log_item *lip)
{
struct xfs_dquot *dqp = DQUOT_ITEM(lip)->qli_dquot;
if (atomic_read(&dqp->q_pincount) > 0)
return XFS_ITEM_PINNED;
if (!xfs_qm_dqlock_nowait(dqp))
return XFS_ITEM_LOCKED;
if (!xfs_dqflock_nowait(dqp)) {
/*
* dquot has already been flushed to the backing buffer,
* leave it locked, pushbuf routine will unlock it.
*/
return XFS_ITEM_PUSHBUF;
}
ASSERT(lip->li_flags & XFS_LI_IN_AIL);
return XFS_ITEM_SUCCESS;
}
STATIC void
xfs_qm_dqreclaim_one(
struct xfs_dquot *dqp,
struct list_head *buffer_list,
struct list_head *dispose_list)
{
struct xfs_mount *mp = dqp->q_mount;
struct xfs_quotainfo *qi = mp->m_quotainfo;
int error;
if (!xfs_dqlock_nowait(dqp))
goto out_move_tail;
/*
* This dquot has acquired a reference in the meantime remove it from
* the freelist and try again.
*/
if (dqp->q_nrefs) {
xfs_dqunlock(dqp);
trace_xfs_dqreclaim_want(dqp);
XFS_STATS_INC(xs_qm_dqwants);
list_del_init(&dqp->q_lru);
qi->qi_lru_count--;
XFS_STATS_DEC(xs_qm_dquot_unused);
return;
}
/*
* Try to grab the flush lock. If this dquot is in the process of
* getting flushed to disk, we don't want to reclaim it.
*/
if (!xfs_dqflock_nowait(dqp))
goto out_unlock_move_tail;
if (XFS_DQ_IS_DIRTY(dqp)) {
struct xfs_buf *bp = NULL;
trace_xfs_dqreclaim_dirty(dqp);
error = xfs_qm_dqflush(dqp, &bp);
if (error) {
xfs_warn(mp, "%s: dquot %p flush failed",
__func__, dqp);
goto out_unlock_move_tail;
}
xfs_buf_delwri_queue(bp, buffer_list);
xfs_buf_relse(bp);
/*
* Give the dquot another try on the freelist, as the
* flushing will take some time.
*/
goto out_unlock_move_tail;
}
xfs_dqfunlock(dqp);
/*
* Prevent lookups now that we are past the point of no return.
*/
dqp->dq_flags |= XFS_DQ_FREEING;
xfs_dqunlock(dqp);
ASSERT(dqp->q_nrefs == 0);
list_move_tail(&dqp->q_lru, dispose_list);
qi->qi_lru_count--;
XFS_STATS_DEC(xs_qm_dquot_unused);
trace_xfs_dqreclaim_done(dqp);
XFS_STATS_INC(xs_qm_dqreclaims);
return;
/*
* Move the dquot to the tail of the list so that we don't spin on it.
*/
out_unlock_move_tail:
xfs_dqunlock(dqp);
out_move_tail:
list_move_tail(&dqp->q_lru, &qi->qi_lru_list);
trace_xfs_dqreclaim_busy(dqp);
XFS_STATS_INC(xs_qm_dqreclaim_misses);
}
/* ARGSUSED */
int
xfs_qm_dqpurge(
xfs_dquot_t *dqp)
{
xfs_dqhash_t *thishash;
xfs_mount_t *mp = dqp->q_mount;
ASSERT(XFS_QM_IS_MPLIST_LOCKED(mp));
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(XFS_DQ_IS_ON_FREELIST(dqp));
/*
* 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;
xfs_dqtrace_entry(dqp, "DQPURGE ->DQFLUSH: DQDIRTY");
/* 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, XFS_QMOPT_SYNC);
if (error)
xfs_fs_cmn_err(CE_WARN, mp,
"xfs_qm_dqpurge: dquot %p flush failed", 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));
thishash = dqp->q_hash;
XQM_HASHLIST_REMOVE(thishash, dqp);
XQM_MPLIST_REMOVE(&(XFS_QI_MPL_LIST(mp)), dqp);
/*
* XXX Move this to the front of the freelist, if we can get the
* freelist lock.
*/
ASSERT(XFS_DQ_IS_ON_FREELIST(dqp));
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(&thishash->qh_lock);
return (0);
}
