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, 17 insertions, 10 deletions

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 2837220ea5cf..c83f63b33aae 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -566,24 +566,31 @@ xfs_trans_init(
 
 /*
  * This routine is called to allocate a transaction structure.
- *
  * The type parameter indicates the type of the transaction.  These
  * are enumerated in xfs_trans.h.
+ *
+ * Dynamically allocate the transaction structure from the transaction
+ * zone, initialize it, and return it to the caller.
  */
-struct xfs_trans *
+xfs_trans_t *
+xfs_trans_alloc(
+	xfs_mount_t	*mp,
+	uint		type)
+{
+	xfs_wait_for_freeze(mp, SB_FREEZE_TRANS);
+	return _xfs_trans_alloc(mp, type, KM_SLEEP);
+}
+
+xfs_trans_t *
 _xfs_trans_alloc(
-	struct xfs_mount	*mp,
-	uint			type,
-	uint			memflags,
-	bool			wait_for_freeze)
+	xfs_mount_t	*mp,
+	uint		type,
+	uint		memflags)
 {
-	struct xfs_trans	*tp;
+	xfs_trans_t	*tp;
 
 	atomic_inc(&mp->m_active_trans);
 
-	if (wait_for_freeze)
-		xfs_wait_for_freeze(mp, SB_FREEZE_TRANS);
-
 	tp = kmem_zone_zalloc(xfs_trans_zone, memflags);
 	tp->t_magic = XFS_TRANS_MAGIC;
 	tp->t_type = type;