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authorAlex Elder <aelder@sgi.com>2011-07-11 09:51:44 -0500
committerAlex Elder <aelder@sgi.com>2011-07-11 10:21:03 -0500
commitb2ce39740066604288876c752d8170b3b17a21aa (patch)
treefd51670cea52d4c4421ce98a65e8b4979535fb97 /fs/xfs/xfs_mount.c
parent81463b1ca8dbd2f4f180feac3f49c7640e2b5f79 (diff)
downloadlinux-b2ce39740066604288876c752d8170b3b17a21aa.tar.bz2
Revert "xfs: fix filesystsem freeze race in xfs_trans_alloc"
This reverts commit 7a249cf83da1813cfa71cfe1e265b40045eceb47. That commit created a situation that could lead to a filesystem hang. As Dave Chinner pointed out, xfs_trans_alloc() could hold a reference to m_active_trans (i.e., keep it non-zero) and then wait for SB_FREEZE_TRANS to complete. Meanwhile a filesystem freeze request could set SB_FREEZE_TRANS and then wait for m_active_trans to drop to zero. Nobody benefits from this sequence of events... Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_mount.c')
-rw-r--r--fs/xfs/xfs_mount.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 2be5e5cf897a..a19e92381f90 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1559,9 +1559,15 @@ xfs_fs_writable(xfs_mount_t *mp)
}
/*
+ * xfs_log_sbcount
+ *
* Called either periodically to keep the on disk superblock values
* roughly up to date or from unmount to make sure the values are
* correct on a clean unmount.
+ *
+ * Note this code can be called during the process of freezing, so
+ * we may need to use the transaction allocator which does not not
+ * block when the transaction subsystem is in its frozen state.
*/
int
xfs_log_sbcount(
@@ -1583,13 +1589,7 @@ xfs_log_sbcount(
if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
return 0;
- /*
- * We can be called during the process of freezing, so make sure
- * we go ahead even if the frozen for new transactions. We will
- * always use a sync transaction in the freeze path to make sure
- * the transaction has completed by the time we return.
- */
- tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_COUNT, KM_SLEEP, false);
+ tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_COUNT, KM_SLEEP);
error = xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
XFS_DEFAULT_LOG_COUNT);
if (error) {