xfs: close xc_cil list_empty() races with cil commit sequence

[firefly-linux-kernel-4.4.55.git] / fs / xfs / xfs_log_cil.c

diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index abc2ccbff73918663b374d795ad15bf803fa4c5b..4e7649351f5a25ab062396818861c9d7c2ee0d61 100644 (file)
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -307,7 +307,13 @@ xlog_cil_insert_items(
                if (!(lidp->lid_flags & XFS_LID_DIRTY))
                        continue;
 
-               list_move_tail(&lip->li_cil, &cil->xc_cil);
+               /*
+                * Only move the item if it isn't already at the tail. This is
+                * to prevent a transient list_empty() state when reinserting
+                * an item that is already the only item in the CIL.
+                */
+               if (!list_is_last(&lip->li_cil, &cil->xc_cil))
+                       list_move_tail(&lip->li_cil, &cil->xc_cil);
        }
 
        /* account for space used by new iovec headers  */