[XFS] Use KM_NOFS for debug trace buffers

Use KM_NOFS to prevent recursion back into the filesystem which can cause
deadlocks.

In the case of xfs_iread() we hold the lock on the inode cluster buffer
while allocating memory for the trace buffers. If we recurse back into XFS
to flush data that may require a transaction to allocate extents which
needs log space. This can deadlock with the xfsaild thread which can't
push the tail of the log because it is trying to get the inode cluster
buffer lock.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31838a

Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 9c23864d4fd0..1f6f780dbd39 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -160,7 +160,7 @@ void
 xlog_trace_iclog(xlog_in_core_t *iclog, uint state)
 {
         if (!iclog->ic_trace)
-                iclog->ic_trace = ktrace_alloc(256, KM_SLEEP);
+                iclog->ic_trace = ktrace_alloc(256, KM_NOFS);
         ktrace_enter(iclog->ic_trace,
                      (void *)((unsigned long)state),
                      (void *)((unsigned long)current_pid()),