/*
* This is called when IOP_TRYLOCK returns XFS_ITEM_PUSHBUF to indicate that
* the dquot is locked by us, but the flush lock isn't. So, here we are
* going to see if the relevant dquot buffer is incore, waiting on DELWRI.
* If so, we want to push it out to help us take this item off the AIL as soon
* as possible.
*
* We must not be holding the AIL lock at this point. Calling incore() to
* search the buffer cache can be a time consuming thing, and AIL lock is a
* spinlock.
*/
STATIC void
xfs_qm_dquot_logitem_pushbuf(
xfs_dq_logitem_t *qip)
{
xfs_dquot_t *dqp;
xfs_mount_t *mp;
xfs_buf_t *bp;
uint dopush;
dqp = qip->qli_dquot;
ASSERT(XFS_DQ_IS_LOCKED(dqp));
/*
* The qli_pushbuf_flag keeps others from
* trying to duplicate our effort.
*/
ASSERT(qip->qli_pushbuf_flag != 0);
ASSERT(qip->qli_push_owner == current_pid());
/*
* If flushlock isn't locked anymore, chances are that the
* inode flush completed and the inode was taken off the AIL.
* So, just get out.
*/
if (!issemalocked(&(dqp->q_flock)) ||
((qip->qli_item.li_flags & XFS_LI_IN_AIL) == 0)) {
qip->qli_pushbuf_flag = 0;
xfs_dqunlock(dqp);
return;
}
mp = dqp->q_mount;
bp = xfs_incore(mp->m_ddev_targp, qip->qli_format.qlf_blkno,
XFS_QI_DQCHUNKLEN(mp),
XFS_INCORE_TRYLOCK);
if (bp != NULL) {
if (XFS_BUF_ISDELAYWRITE(bp)) {
dopush = ((qip->qli_item.li_flags & XFS_LI_IN_AIL) &&
issemalocked(&(dqp->q_flock)));
qip->qli_pushbuf_flag = 0;
xfs_dqunlock(dqp);
if (XFS_BUF_ISPINNED(bp)) {
xfs_log_force(mp, (xfs_lsn_t)0,
XFS_LOG_FORCE);
}
if (dopush) {
int error;
#ifdef XFSRACEDEBUG
delay_for_intr();
delay(300);
#endif
error = xfs_bawrite(mp, bp);
if (error)
xfs_fs_cmn_err(CE_WARN, mp,
"xfs_qm_dquot_logitem_pushbuf: pushbuf error %d on qip %p, bp %p",
error, qip, bp);
} else {
xfs_buf_relse(bp);
}
} else {
qip->qli_pushbuf_flag = 0;
xfs_dqunlock(dqp);
xfs_buf_relse(bp);
}
return;
}
qip->qli_pushbuf_flag = 0;
xfs_dqunlock(dqp);
}
/*
* xfs_trans_push_ail
*
* This routine is called to move the tail of the AIL
* forward. It does this by trying to flush items in the AIL
* whose lsns are below the given threshold_lsn.
*
* The routine returns the lsn of the tail of the log.
*/
xfs_lsn_t
xfs_trans_push_ail(
xfs_mount_t *mp,
xfs_lsn_t threshold_lsn)
{
xfs_lsn_t lsn;
xfs_log_item_t *lip;
int gen;
int restarts;
int lock_result;
int flush_log;
SPLDECL(s);
#define XFS_TRANS_PUSH_AIL_RESTARTS 10
AIL_LOCK(mp,s);
lip = xfs_trans_first_ail(mp, &gen);
if (lip == NULL || XFS_FORCED_SHUTDOWN(mp)) {
/*
* Just return if the AIL is empty.
*/
AIL_UNLOCK(mp, s);
return (xfs_lsn_t)0;
}
XFS_STATS_INC(xs_push_ail);
/*
* While the item we are looking at is below the given threshold
* try to flush it out. Make sure to limit the number of times
* we allow xfs_trans_next_ail() to restart scanning from the
* beginning of the list. We'd like not to stop until we've at least
* tried to push on everything in the AIL with an LSN less than
* the given threshold. However, we may give up before that if
* we realize that we've been holding the AIL_LOCK for 'too long',
* blocking interrupts. Currently, too long is < 500us roughly.
*/
flush_log = 0;
restarts = 0;
while (((restarts < XFS_TRANS_PUSH_AIL_RESTARTS) &&
(XFS_LSN_CMP(lip->li_lsn, threshold_lsn) < 0))) {
/*
* If we can lock the item without sleeping, unlock
* the AIL lock and flush the item. Then re-grab the
* AIL lock so we can look for the next item on the
* AIL. Since we unlock the AIL while we flush the
* item, the next routine may start over again at the
* the beginning of the list if anything has changed.
* That is what the generation count is for.
*
* If we can't lock the item, either its holder will flush
* it or it is already being flushed or it is being relogged.
* In any of these case it is being taken care of and we
* can just skip to the next item in the list.
*/
lock_result = IOP_TRYLOCK(lip);
switch (lock_result) {
case XFS_ITEM_SUCCESS:
AIL_UNLOCK(mp, s);
XFS_STATS_INC(xs_push_ail_success);
IOP_PUSH(lip);
AIL_LOCK(mp,s);
break;
case XFS_ITEM_PUSHBUF:
AIL_UNLOCK(mp, s);
XFS_STATS_INC(xs_push_ail_pushbuf);
#ifdef XFSRACEDEBUG
delay_for_intr();
delay(300);
#endif
ASSERT(lip->li_ops->iop_pushbuf);
ASSERT(lip);
IOP_PUSHBUF(lip);
AIL_LOCK(mp,s);
break;
case XFS_ITEM_PINNED:
XFS_STATS_INC(xs_push_ail_pinned);
flush_log = 1;
break;
case XFS_ITEM_LOCKED:
XFS_STATS_INC(xs_push_ail_locked);
break;
case XFS_ITEM_FLUSHING:
XFS_STATS_INC(xs_push_ail_flushing);
break;
default:
ASSERT(0);
break;
}
lip = xfs_trans_next_ail(mp, lip, &gen, &restarts);
if (lip == NULL) {
break;
}
if (XFS_FORCED_SHUTDOWN(mp)) {
/*
* Just return if we shut down during the last try.
*/
AIL_UNLOCK(mp, s);
return (xfs_lsn_t)0;
}
}
if (flush_log) {
/*
* If something we need to push out was pinned, then
* push out the log so it will become unpinned and
* move forward in the AIL.
*/
AIL_UNLOCK(mp, s);
XFS_STATS_INC(xs_push_ail_flush);
xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
AIL_LOCK(mp, s);
}
lip = xfs_ail_min(&(mp->m_ail));
if (lip == NULL) {
lsn = (xfs_lsn_t)0;
} else {
lsn = lip->li_lsn;
}
AIL_UNLOCK(mp, s);
return lsn;
} /* xfs_trans_push_ail */
