Merge tag 'char-misc-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregk...

[karo-tx-linux.git] / fs / xfs / libxfs / xfs_bmap.c

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 0a9880777c9c2ff51846e09efde4933e5a6ace3d..c09c16b1ad3b8b1f883e2ee93b9fcc275c7ed63c 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5435,6 +5435,7 @@ __xfs_bunmapi(
        xfs_fsblock_t           sum;
        xfs_filblks_t           len = *rlen;    /* length to unmap in file */
        xfs_fileoff_t           max_len;
+       xfs_agnumber_t          prev_agno = NULLAGNUMBER, agno;
 
        trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_);
 
@@ -5534,6 +5535,17 @@ __xfs_bunmapi(
                 */
                del = got;
                wasdel = isnullstartblock(del.br_startblock);
+
+               /*
+                * Make sure we don't touch multiple AGF headers out of order
+                * in a single transaction, as that could cause AB-BA deadlocks.
+                */
+               if (!wasdel) {
+                       agno = XFS_FSB_TO_AGNO(mp, del.br_startblock);
+                       if (prev_agno != NULLAGNUMBER && prev_agno > agno)
+                               break;
+                       prev_agno = agno;
+               }
                if (got.br_startoff < start) {
                        del.br_startoff = start;
                        del.br_blockcount -= start - got.br_startoff;
@@ -6499,6 +6511,15 @@ xfs_bmap_finish_one(
        xfs_fsblock_t                   firstfsb;
        int                             error = 0;
 
+       /*
+        * firstfsb is tied to the transaction lifetime and is used to
+        * ensure correct AG locking order and schedule work item
+        * continuations.  XFS_BUI_MAX_FAST_EXTENTS (== 1) restricts us
+        * to only making one bmap call per transaction, so it should
+        * be safe to have it as a local variable here.
+        */
+       firstfsb = NULLFSBLOCK;
+
        trace_xfs_bmap_deferred(tp->t_mountp,
                        XFS_FSB_TO_AGNO(tp->t_mountp, startblock), type,
                        XFS_FSB_TO_AGBNO(tp->t_mountp, startblock),