xfs: defer agfl block frees from deferred ops processing context

Source kernel commit: 2bc5eba8b6957824631205aeffc75db8dbb5426a

Now that AGFL block frees are deferred when dfops is set in the
transaction, start deferring AGFL block frees from contexts that are
known to push the limits of existing log reservations.

The first such context is deferred operation processing itself. This
primarily targets deferred extent frees (such as file extents and
inode chunks), but in doing so covers all allocation operations that
occur in deferred operation processing context.

Update xfs_defer_finish() to set and reset ->t_agfl_dfops across the
processing sequence. This means that any AGFL block frees due to
allocation events result in the addition of new EFIs to the dfops
rather than being processed immediately. xfs_defer_finish() rolls
the transaction at least once more to process the frees of the AGFL
blocks back to the allocation btrees and returns once the AGFL is
rectified.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_defer.c b/libxfs/xfs_defer.c
index 2b07a2e7e78064f2141ab308012203ba3c1c2eb0..717e836899b7ebc12540057729b8926a2da216c1 100644 (file)
--- a/libxfs/xfs_defer.c
+++ b/libxfs/xfs_defer.c
@@ -352,11 +352,22 @@ xfs_defer_finish(
        void                            *state;
        int                             error = 0;
        void                            (*cleanup_fn)(struct xfs_trans *, void *, int);
+       struct xfs_defer_ops            *orig_dop;
 
        ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
 
        trace_xfs_defer_finish((*tp)->t_mountp, dop);
 
+       /*
+        * Attach dfops to the transaction during deferred ops processing. This
+        * explicitly causes calls into the allocator to defer AGFL block frees.
+        * Note that this code can go away once all dfops users attach to the
+        * associated tp.
+        */
+       ASSERT(!(*tp)->t_agfl_dfops || ((*tp)->t_agfl_dfops == dop));
+       orig_dop = (*tp)->t_agfl_dfops;
+       (*tp)->t_agfl_dfops = dop;
+
        /* Until we run out of pending work to finish... */
        while (xfs_defer_has_unfinished_work(dop)) {
                /* Log intents for work items sitting in the intake. */
@@ -428,6 +439,7 @@ xfs_defer_finish(
        }
 
 out:
+       (*tp)->t_agfl_dfops = orig_dop;
        if (error)
                trace_xfs_defer_finish_error((*tp)->t_mountp, dop, error);
        else