diff options
| author | Dave Chinner <dchinner@redhat.com> | 2011-05-06 06:54:07 +0400 |
|---|---|---|
| committer | Alex Elder <aelder@sgi.com> | 2011-05-09 21:17:04 +0400 |
| commit | fd5670f22fce247754243cf2ed41941e5762d990 (patch) | |
| tree | 4574bf415df6d3c8a5c501ee3b02727dd573ba03 /fs/xfs | |
| parent | cb64026b6e8af50db598ec7c3f59d504259b00bb (diff) | |
| download | linux-fd5670f22fce247754243cf2ed41941e5762d990.tar.xz | |
xfs: make AIL target updates and compares 32bit safe.
The recent conversion of the xfsaild functionality to a work queue
introduced a hard-to-hit log space grant hang. One of the problems
noticed was that updates of the push target are not 32 bit safe as
the target is a 64 bit value.
We cannot copy a 64 bit LSN without the possibility of corrupting
the result when racing with another updating thread. We have
function to do this update safely without needing to care about
32/64 bit issues - xfs_trans_ail_copy_lsn() - so use that when
updating the AIL push target.
Also move the reading of the target in the push work inside the AIL
lock, and use XFS_LSN_CMP() for the unlocked comparison during work
termination to close read holes as well.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Diffstat (limited to 'fs/xfs')
| -rw-r--r-- | fs/xfs/xfs_trans_ail.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 9f427c2597bb..d7eebbf71362 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -354,7 +354,7 @@ xfs_ail_worker( struct xfs_ail_cursor *cur = &ailp->xa_cursors; xfs_log_item_t *lip; xfs_lsn_t lsn; - xfs_lsn_t target = ailp->xa_target; + xfs_lsn_t target; long tout = 10; int flush_log = 0; int stuck = 0; @@ -362,6 +362,7 @@ xfs_ail_worker( int push_xfsbufd = 0; spin_lock(&ailp->xa_lock); + target = ailp->xa_target; xfs_trans_ail_cursor_init(ailp, cur); lip = xfs_trans_ail_cursor_first(ailp, cur, ailp->xa_last_pushed_lsn); if (!lip || XFS_FORCED_SHUTDOWN(mp)) { @@ -491,7 +492,7 @@ out_done: * work to do. Wait a bit longer before starting that work. */ smp_rmb(); - if (ailp->xa_target == target) { + if (XFS_LSN_CMP(ailp->xa_target, target) == 0) { clear_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags); return; } @@ -553,7 +554,7 @@ xfs_ail_push( * the XFS_AIL_PUSHING_BIT. */ smp_wmb(); - ailp->xa_target = threshold_lsn; + xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn); if (!test_and_set_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags)) queue_delayed_work(xfs_syncd_wq, &ailp->xa_work, 0); } |