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xfs: refactor xfs_log_force

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Streamline the conditionals so that it is more obvious which specific case
form the top of the function comments is being handled.  Use gotos only
for early returns.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Christoph Hellwig 2018-03-13 23:15:29 -07:00 committed by Darrick J. Wong
parent 656de4ffaf
commit e6b9657056
1 changed files with 66 additions and 84 deletions
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150
fs/xfs/xfs_log.c
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@ -3318,99 +3318,81 @@ xfs_log_force(
xlog_cil_force(log);
spin_lock(&log->l_icloglock);
iclog = log->l_iclog;
if (iclog->ic_state & XLOG_STATE_IOERROR) {
spin_unlock(&log->l_icloglock);
return -EIO;
}
if (iclog->ic_state & XLOG_STATE_IOERROR)
goto out_error;
/* If the head iclog is not active nor dirty, we just attach
* ourselves to the head and go to sleep.
*/
if (iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY) {
if (iclog->ic_state == XLOG_STATE_DIRTY ||
(iclog->ic_state == XLOG_STATE_ACTIVE &&
atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
/*
* If the head is dirty or (active and empty), then
* we need to look at the previous iclog. If the previous
* iclog is active or dirty we are done. There is nothing
* to sync out. Otherwise, we attach ourselves to the
* If the head is dirty or (active and empty), then we need to
* look at the previous iclog.
*
* If the previous iclog is active or dirty we are done. There
* is nothing to sync out. Otherwise, we attach ourselves to the
* previous iclog and go to sleep.
*/
if (iclog->ic_state == XLOG_STATE_DIRTY ||
(atomic_read(&iclog->ic_refcnt) == 0
&& iclog->ic_offset == 0)) {
iclog = iclog->ic_prev;
if (iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY)
goto no_sleep;
else
goto maybe_sleep;
} else {
if (atomic_read(&iclog->ic_refcnt) == 0) {
/* We are the only one with access to this
* iclog. Flush it out now. There should
* be a roundoff of zero to show that someone
* has already taken care of the roundoff from
* the previous sync.
*/
atomic_inc(&iclog->ic_refcnt);
lsn = be64_to_cpu(iclog->ic_header.h_lsn);
xlog_state_switch_iclogs(log, iclog, 0);
spin_unlock(&log->l_icloglock);
if (xlog_state_release_iclog(log, iclog))
return -EIO;
spin_lock(&log->l_icloglock);
if (be64_to_cpu(iclog->ic_header.h_lsn) == lsn &&
iclog->ic_state != XLOG_STATE_DIRTY)
goto maybe_sleep;
else
goto no_sleep;
} else {
/* Someone else is writing to this iclog.
* Use its call to flush out the data. However,
* the other thread may not force out this LR,
* so we mark it WANT_SYNC.
*/
xlog_state_switch_iclogs(log, iclog, 0);
goto maybe_sleep;
}
}
}
/* By the time we come around again, the iclog could've been filled
* which would give it another lsn. If we have a new lsn, just
* return because the relevant data has been flushed.
*/
maybe_sleep:
if (flags & XFS_LOG_SYNC) {
/*
* We must check if we're shutting down here, before
* we wait, while we're holding the l_icloglock.
* Then we check again after waking up, in case our
* sleep was disturbed by a bad news.
*/
if (iclog->ic_state & XLOG_STATE_IOERROR) {
iclog = iclog->ic_prev;
if (iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY)
goto out_unlock;
} else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
if (atomic_read(&iclog->ic_refcnt) == 0) {
/*
* We are the only one with access to this iclog.
*
* Flush it out now. There should be a roundoff of zero
* to show that someone has already taken care of the
* roundoff from the previous sync.
*/
atomic_inc(&iclog->ic_refcnt);
lsn = be64_to_cpu(iclog->ic_header.h_lsn);
xlog_state_switch_iclogs(log, iclog, 0);
spin_unlock(&log->l_icloglock);
return -EIO;
}
XFS_STATS_INC(mp, xs_log_force_sleep);
xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
/*
* No need to grab the log lock here since we're
* only deciding whether or not to return EIO
* and the memory read should be atomic.
*/
if (iclog->ic_state & XLOG_STATE_IOERROR)
return -EIO;
} else {
no_sleep:
spin_unlock(&log->l_icloglock);
if (xlog_state_release_iclog(log, iclog))
return -EIO;
spin_lock(&log->l_icloglock);
if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn ||
iclog->ic_state == XLOG_STATE_DIRTY)
goto out_unlock;
} else {
/*
* Someone else is writing to this iclog.
*
* Use its call to flush out the data. However, the
* other thread may not force out this LR, so we mark
* it WANT_SYNC.
*/
xlog_state_switch_iclogs(log, iclog, 0);
}
} else {
/*
* If the head iclog is not active nor dirty, we just attach
* ourselves to the head and go to sleep if necessary.
*/
;
}
if (!(flags & XFS_LOG_SYNC))
goto out_unlock;
if (iclog->ic_state & XLOG_STATE_IOERROR)
goto out_error;
XFS_STATS_INC(mp, xs_log_force_sleep);
xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
if (iclog->ic_state & XLOG_STATE_IOERROR)
return -EIO;
return 0;
out_unlock:
spin_unlock(&log->l_icloglock);
return 0;
out_error:
spin_unlock(&log->l_icloglock);
return -EIO;
}
/*