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xfs: remove periodic superblock writeback

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All modifications to the superblock are done transactional through
xfs_trans_log_buf, so there is no reason to initiate periodic
asynchronous writeback.  This only removes the superblock from the
delwri list and will lead to sub-optimal I/O scheduling.

Cut down xfs_sync_fsdata now that it's only used for synchronous
superblock writes and move the log coverage checks into the two
callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
This commit is contained in:
Christoph Hellwig 2010-03-12 10:59:16 +00:00 committed by Alex Elder
parent f983710758
commit df308bcfec
1 changed files with 27 additions and 63 deletions
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90
fs/xfs/linux-2.6/xfs_sync.c
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@ -356,68 +356,24 @@ xfs_commit_dummy_trans(
STATIC int
xfs_sync_fsdata(
struct xfs_mount *mp,
int flags)
struct xfs_mount *mp)
{
struct xfs_buf *bp;
struct xfs_buf_log_item *bip;
int error = 0;
/*
* If this is xfssyncd() then only sync the superblock if we can
* lock it without sleeping and it is not pinned.
* If the buffer is pinned then push on the log so we won't get stuck
* waiting in the write for someone, maybe ourselves, to flush the log.
*
* Even though we just pushed the log above, we did not have the
* superblock buffer locked at that point so it can become pinned in
* between there and here.
*/
if (flags & SYNC_TRYLOCK) {
ASSERT(!(flags & SYNC_WAIT));
bp = xfs_getsb(mp, 0);
if (XFS_BUF_ISPINNED(bp))
xfs_log_force(mp, 0);
bp = xfs_getsb(mp, XBF_TRYLOCK);
if (!bp)
goto out;
bip = XFS_BUF_FSPRIVATE(bp, struct xfs_buf_log_item *);
if (!bip || !xfs_buf_item_dirty(bip) || XFS_BUF_ISPINNED(bp))
goto out_brelse;
} else {
bp = xfs_getsb(mp, 0);
/*
* If the buffer is pinned then push on the log so we won't
* get stuck waiting in the write for someone, maybe
* ourselves, to flush the log.
*
* Even though we just pushed the log above, we did not have
* the superblock buffer locked at that point so it can
* become pinned in between there and here.
*/
if (XFS_BUF_ISPINNED(bp))
xfs_log_force(mp, 0);
}
if (flags & SYNC_WAIT)
XFS_BUF_UNASYNC(bp);
else
XFS_BUF_ASYNC(bp);
error = xfs_bwrite(mp, bp);
if (error)
return error;
/*
* If this is a data integrity sync make sure all pending buffers
* are flushed out for the log coverage check below.
*/
if (flags & SYNC_WAIT)
xfs_flush_buftarg(mp->m_ddev_targp, 1);
if (xfs_log_need_covered(mp))
error = xfs_commit_dummy_trans(mp, flags);
return error;
out_brelse:
xfs_buf_relse(bp);
out:
return error;
XFS_BUF_UNASYNC(bp);
return xfs_bwrite(mp, bp);
}
/*
@ -441,7 +397,7 @@ int
xfs_quiesce_data(
struct xfs_mount *mp)
{
int error;
int error, error2 = 0;
/* push non-blocking */
xfs_sync_data(mp, 0);
@ -452,13 +408,20 @@ xfs_quiesce_data(
xfs_qm_sync(mp, SYNC_WAIT);
/* write superblock and hoover up shutdown errors */
error = xfs_sync_fsdata(mp, SYNC_WAIT);
error = xfs_sync_fsdata(mp);
/* make sure all delwri buffers are written out */
xfs_flush_buftarg(mp->m_ddev_targp, 1);
/* mark the log as covered if needed */
if (xfs_log_need_covered(mp))
error2 = xfs_commit_dummy_trans(mp, SYNC_WAIT);
/* flush data-only devices */
if (mp->m_rtdev_targp)
XFS_bflush(mp->m_rtdev_targp);
return error;
return error ? error : error2;
}
STATIC void
@ -581,9 +544,9 @@ xfs_flush_inodes(
}
/*
* Every sync period we need to unpin all items, reclaim inodes, sync
* quota and write out the superblock. We might need to cover the log
* to indicate it is idle.
* Every sync period we need to unpin all items, reclaim inodes and sync
* disk quotas. We might need to cover the log to indicate that the
* filesystem is idle.
*/
STATIC void
xfs_sync_worker(
@ -597,7 +560,8 @@ xfs_sync_worker(
xfs_reclaim_inodes(mp, 0);
/* dgc: errors ignored here */
error = xfs_qm_sync(mp, SYNC_TRYLOCK);
error = xfs_sync_fsdata(mp, SYNC_TRYLOCK);
if (xfs_log_need_covered(mp))
error = xfs_commit_dummy_trans(mp, 0);
}
mp->m_sync_seq++;
wake_up(&mp->m_wait_single_sync_task);