[Cluster-devel] [GFS2 PATCH 2/3] gfs2: Retry on dlm -EBUSY (stop gap)

[Bob Peterson]

Sometimes when gfs2 cancels a glock request, dlm needs time to take the
request off its Conversion queue. During that time, we get -EBUSY from
dlm, which confuses the glock state machine. Ideally we want dlm to
not return -EBUSY but wait until the operation has completed. This is
a stop-gap measure until dlm has a solution in place.

Signed-off-by: Bob Peterson <rpete...@redhat.com>
---
 fs/gfs2/lock_dlm.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
index 50578f881e6d..bf03c77b6757 100644
--- a/fs/gfs2/lock_dlm.c
+++ b/fs/gfs2/lock_dlm.c
@@ -258,7 +258,7 @@ static int gdlm_lock(struct gfs2_glock *gl, unsigned int 
req_state,
                     unsigned int flags)
 {
        struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
-       int req;
+       int req, ret;
        u32 lkf;
        char strname[GDLM_STRNAME_BYTES] = "";
 
@@ -278,9 +278,12 @@ static int gdlm_lock(struct gfs2_glock *gl, unsigned int 
req_state,
        /*
         * Submit the actual lock request.
         */
-
-       return dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, strname,
-                       GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
+       do {
+               ret = dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, strname,
+                              GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl,
+                              gdlm_bast);
+       } while (ret == -EBUSY);
+       return ret;
 }
 
 static void gdlm_put_lock(struct gfs2_glock *gl)
@@ -312,8 +315,11 @@ static void gdlm_put_lock(struct gfs2_glock *gl)
                return;
        }
 
-       error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
-                          NULL, gl);
+       do {
+               error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid,
+                                  DLM_LKF_VALBLK, NULL, gl);
+       } while (error == -EBUSY);
+
        if (error) {
                fs_err(sdp, "gdlm_unlock %x,%llx err=%d\n",
                       gl->gl_name.ln_type,
@@ -506,7 +512,9 @@ static int sync_unlock(struct gfs2_sbd *sdp, struct 
dlm_lksb *lksb, char *name)
        struct lm_lockstruct *ls = &sdp->sd_lockstruct;
        int error;
 
-       error = dlm_unlock(ls->ls_dlm, lksb->sb_lkid, 0, lksb, ls);
+       do {
+               error = dlm_unlock(ls->ls_dlm, lksb->sb_lkid, 0, lksb, ls);
+       } while (error == -EBUSY);
        if (error) {
                fs_err(sdp, "%s lkid %x error %d\n",
                       name, lksb->sb_lkid, error);
-- 
2.34.1