xfs: add tracepoints to AGF/AGI read operations

To help track down AGI/AGF lock ordering issues, I added these
tracepoints to tell us when an AGI or AGF is read and locked.  With
these we can now determine if the lock ordering goes wrong from
tracing captures.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index bcf16528bac5..9eab2dfdcbb5 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -2294,6 +2294,8 @@ xfs_read_agf(
 {
         int             error;
 
+        trace_xfs_read_agf(mp, agno);
+
         ASSERT(agno != NULLAGNUMBER);
         error = xfs_trans_read_buf(
                         mp, tp, mp->m_ddev_targp,
@@ -2324,8 +2326,9 @@ xfs_alloc_read_agf(
         struct xfs_perag        *pag;           /* per allocation group data */
         int                     error;
 
-        ASSERT(agno != NULLAGNUMBER);
+        trace_xfs_alloc_read_agf(mp, agno);
 
+        ASSERT(agno != NULLAGNUMBER);
         error = xfs_read_agf(mp, tp, agno,
                         (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
                         bpp);