/*
* 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(
xfs_dq_logitem_t *qip)
{
xfs_dquot_t *dqp;
uint retval;
dqp = qip->qli_dquot;
if (dqp->q_pincount > 0)
return (XFS_ITEM_PINNED);
if (! xfs_qm_dqlock_nowait(dqp))
return (XFS_ITEM_LOCKED);
retval = XFS_ITEM_SUCCESS;
if (! xfs_qm_dqflock_nowait(dqp)) {
/*
* The dquot is already being flushed. It may have been
* flushed delayed write, however, and we don't want to
* get stuck waiting for that to complete. So, we want to check
* to see if we can lock the dquot's buffer without sleeping.
* If we can and it is marked for delayed write, then we
* hold it and send it out from the push routine. We don't
* want to do that now since we might sleep in the device
* strategy routine. We also don't want to grab the buffer lock
* here because we'd like not to call into the buffer cache
* while holding the AIL lock.
* Make sure to only return PUSHBUF if we set pushbuf_flag
* ourselves. If someone else is doing it then we don't
* want to go to the push routine and duplicate their efforts.
*/
if (qip->qli_pushbuf_flag == 0) {
qip->qli_pushbuf_flag = 1;
ASSERT(qip->qli_format.qlf_blkno == dqp->q_blkno);
#ifdef DEBUG
qip->qli_push_owner = current_pid();
#endif
/*
* The dquot is left locked.
*/
retval = XFS_ITEM_PUSHBUF;
} else {
retval = XFS_ITEM_FLUSHING;
xfs_dqunlock_nonotify(dqp);
}
}
ASSERT(qip->qli_item.li_flags & XFS_LI_IN_AIL);
return (retval);
}
/* ARGSUSED */
int
xfs_qm_dqpurge(
xfs_dquot_t *dqp,
uint flags)
{
xfs_dqhash_t *thishash;
xfs_mount_t *mp;
mp = dqp->q_mount;
ASSERT(XFS_QM_IS_MPLIST_LOCKED(mp));
ASSERT(XFS_DQ_IS_HASH_LOCKED(dqp->q_hash));
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);
XFS_DQ_HASH_UNLOCK(dqp->q_hash);
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_qm_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)) {
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.
*/
(void) xfs_qm_dqflush(dqp, XFS_QMOPT_SYNC);
xfs_dqflock(dqp);
}
ASSERT(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);
XFS_DQ_HASH_UNLOCK(thishash);
return (0);
}