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>

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) {