xfs: allow lazy sb counter sync during filesystem freeze sequence

[cascardo/linux.git] / fs / xfs / xfs_mount.c

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 51435db..13d1170 100644 (file)
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1074,11 +1074,23 @@ xfs_unmountfs(
        xfs_sysfs_del(&mp->m_kobj);
 }
 
-int
-xfs_fs_writable(xfs_mount_t *mp)
+/*
+ * Determine whether modifications can proceed. The caller specifies the minimum
+ * freeze level for which modifications should not be allowed. This allows
+ * certain operations to proceed while the freeze sequence is in progress, if
+ * necessary.
+ */
+bool
+xfs_fs_writable(
+       struct xfs_mount        *mp,
+       int                     level)
 {
-       return !(mp->m_super->s_writers.frozen || XFS_FORCED_SHUTDOWN(mp) ||
-               (mp->m_flags & XFS_MOUNT_RDONLY));
+       ASSERT(level > SB_UNFROZEN);
+       if ((mp->m_super->s_writers.frozen >= level) ||
+           XFS_FORCED_SHUTDOWN(mp) || (mp->m_flags & XFS_MOUNT_RDONLY))
+               return false;
+
+       return true;
 }
 
 /*
@@ -1086,9 +1098,9 @@ xfs_fs_writable(xfs_mount_t *mp)
  *
  * 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.
+ * Note this code can be called during the process of freezing, so we use the
+ * transaction allocator that does not block when the transaction subsystem is
+ * in its frozen state.
  */
 int
 xfs_log_sbcount(xfs_mount_t *mp)
@@ -1096,7 +1108,8 @@ xfs_log_sbcount(xfs_mount_t *mp)
        xfs_trans_t     *tp;
        int             error;
 
-       if (!xfs_fs_writable(mp))
+       /* allow this to proceed during the freeze sequence... */
+       if (!xfs_fs_writable(mp, SB_FREEZE_COMPLETE))
                return 0;
 
        xfs_icsb_sync_counters(mp, 0);