GFS2: Add some useful messages

The following patch adds a message to indicate when barriers have been
disabled due to a block device which doesn't support them. You could
already tell this via the mount options in /proc/mounts, but all the
other filesystems also log a message at the same time.

Also, the same mechanisms are used to indicate when the lock
demote interface has been used (only ever used for debugging)
which is a request from our support team.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
index 2ac845d9c46c..7afb62ec97cf 100644
--- a/fs/gfs2/sys.c
+++ b/fs/gfs2/sys.c
@@ -233,6 +233,8 @@ static ssize_t demote_rq_store(struct gfs2_sbd *sdp, const char *buf, size_t len
         glops = gfs2_glops_list[gltype];
         if (glops == NULL)
                 return -EINVAL;
+        if (test_and_set_bit(SDF_DEMOTE, &sdp->sd_flags))
+                fs_info(sdp, "demote interface used\n");
         rv = gfs2_glock_get(sdp, glnum, glops, 0, &gl);
         if (rv)
                 return rv;