xfs_wait_buftarg() does not wait for the completion of the write of the uncached
superblock. This write can race with the shutdown of the log and cause a panic if the
write does not win the race. Per Dave's suggestion, turn the final write of the
superblock into a syncronous write.
Signed-off-by: Mark Tinguely <tinguely@xxxxxxx>
---
fs/xfs/xfs_mount.c | 43 +++++++++++++++++++------------------------
fs/xfs/xfs_mount.h | 4 +++-
fs/xfs/xfs_sync.c | 8 +-------
3 files changed, 23 insertions(+), 32 deletions(-)
Index: b/fs/xfs/xfs_mount.c
===================================================================
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1517,11 +1517,6 @@ xfs_unmountfs(
xfs_warn(mp, "Unable to free reserved block pool. "
"Freespace may not be correct on next mount.");
- error = xfs_log_sbcount(mp);
- if (error)
- xfs_warn(mp, "Unable to update superblock counters. "
- "Freespace may not be correct on next mount.");
-
/*
* At this point we might have modified the superblock again and thus
* added an item to the AIL, thus flush it again.
@@ -1529,6 +1524,11 @@ xfs_unmountfs(
xfs_ail_push_all_sync(mp->m_ail);
xfs_wait_buftarg(mp->m_ddev_targp);
+ error = xfs_write_sbcount(mp);
+ if (error)
+ xfs_warn(mp, "Unable to update superblock counters. "
+ "Freespace may not be correct on next mount.");
+
xfs_log_unmount_write(mp);
xfs_log_unmount(mp);
xfs_uuid_unmount(mp);
@@ -1547,19 +1547,17 @@ xfs_fs_writable(xfs_mount_t *mp)
}
/*
- * xfs_log_sbcount
+ * xfs_write_sbcount
*
* Sync the superblock counters to disk.
*
- * Note this code can be called during the process of freezing, so
- * we may need to use the transaction allocator which does not
- * block when the transaction subsystem is in its frozen state.
*/
int
-xfs_log_sbcount(xfs_mount_t *mp)
+xfs_write_sbcount(
+ struct xfs_mount *mp)
{
- xfs_trans_t *tp;
- int error;
+ struct xfs_buf *bp;
+ int error;
if (!xfs_fs_writable(mp))
return 0;
@@ -1571,19 +1569,16 @@ xfs_log_sbcount(xfs_mount_t *mp)
* counters on every modification.
*/
if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
- return 0;
+ return 0;
- 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) {
- xfs_trans_cancel(tp, 0);
- return error;
- }
-
- xfs_mod_sb(tp, XFS_SB_IFREE | XFS_SB_ICOUNT | XFS_SB_FDBLOCKS);
- xfs_trans_set_sync(tp);
- error = xfs_trans_commit(tp, 0);
+ bp = xfs_getsb(mp, 0);
+ xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb,
+ XFS_SB_IFREE | XFS_SB_ICOUNT | XFS_SB_FDBLOCKS);
+
+ if (xfs_buf_ispinned(bp))
+ xfs_log_force(mp, 0);
+ error = xfs_bwrite(bp);
+ xfs_buf_relse(bp);
return error;
}
Index: b/fs/xfs/xfs_mount.h
===================================================================
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -371,7 +371,9 @@ typedef struct xfs_mod_sb {
int64_t msb_delta; /* Change to make to specified field */
} xfs_mod_sb_t;
-extern int xfs_log_sbcount(xfs_mount_t *);
+extern int
+xfs_write_sbcount(
+ struct xfs_mount *mp);
extern __uint64_t xfs_default_resblks(xfs_mount_t *mp);
extern int xfs_mountfs(xfs_mount_t *mp);
Index: b/fs/xfs/xfs_sync.c
===================================================================
--- a/fs/xfs/xfs_sync.c
+++ b/fs/xfs/xfs_sync.c
@@ -348,17 +348,11 @@ xfs_quiesce_attr(
WARN_ON(atomic_read(&mp->m_active_trans) != 0);
/* Push the superblock and write an unmount record */
- error = xfs_log_sbcount(mp);
+ error = xfs_write_sbcount(mp);
if (error)
xfs_warn(mp, "xfs_attr_quiesce: failed to log sb changes. "
"Frozen image may not be consistent.");
xfs_log_unmount_write(mp);
-
- /*
- * At this point we might have modified the superblock again and thus
- * added an item to the AIL, thus flush it again.
- */
- xfs_ail_push_all_sync(mp->m_ail);
}
static void
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