[Cluster-devel] [PATCH RFC gfs2/for-next] fs: gfs2: release dlm gfs2 ls on withdraw

[Alexander Aring]

This patch will introduce a new gfs2 lock ops callback for release a
possible lock infrastructure e.g. dlm. There is currently an issue with
gfs2 and dlm by hitting ctrl-c during mount operation (sometimes it
works, most times not). The issue is here that when the gfs2 filesystem
is not withdrawn we don't release the dlm lockspace again and next mount
dlm_new_lockspace() will return -EEXIST. This patch will ensure that we
call dlm_release_lockspace() in the error path of gfs2_fill_super() even if
the filesystem isn't withdrawn yet. Moreover it will do that in all
cases even if the filesystem is not withdrawn yet.

Signed-off-by: Alexander Aring <aahringo at redhat.com>
---
Hi,

no idea if the gfs2_withdrawn(sdp) should be always evaluated to
"false", but then there are cases when it returns "true" and the
gfs2 dlm lockspace will not be released... next mount there will be
a -EEXIST, as described in the commit message.

If gfs2_withdrawn(sdp) should return "false" always maybe there is some
missing wait and we should printout a warning if it's returning true...
in this case and an error path we have a problem which can be observed
at the next mount.

- Alex

 fs/gfs2/glock.h      |  1 +
 fs/gfs2/lock_dlm.c   | 24 ++++++++++++++++++------
 fs/gfs2/ops_fstype.c |  6 +++++-
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index 31a8f2f649b5..c8fd1352b0e1 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -130,6 +130,7 @@ struct lm_lockops {
 	void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
 				    unsigned int result);
 	void (*lm_unmount) (struct gfs2_sbd *sdp);
+	void (*lm_release) (struct gfs2_sbd *sdp);
 	void (*lm_withdraw) (struct gfs2_sbd *sdp);
 	void (*lm_put_lock) (struct gfs2_glock *gl);
 	int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
index 50578f881e6d..776667ca4da1 100644
--- a/fs/gfs2/lock_dlm.c
+++ b/fs/gfs2/lock_dlm.c
@@ -1248,6 +1248,14 @@ static const struct dlm_lockspace_ops gdlm_lockspace_ops = {
 	.recover_done = gdlm_recover_done,
 };
 
+static void gdlm_ls_release(struct lm_lockstruct *ls)
+{
+	if (ls->ls_dlm) {
+		dlm_release_lockspace(ls->ls_dlm, 2);
+		ls->ls_dlm = NULL;
+	}
+}
+
 static int gdlm_mount(struct gfs2_sbd *sdp, const char *table)
 {
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
@@ -1338,7 +1346,7 @@ static int gdlm_mount(struct gfs2_sbd *sdp, const char *table)
 	return 0;
 
 fail_release:
-	dlm_release_lockspace(ls->ls_dlm, 2);
+	gdlm_ls_release(ls);
 fail_free:
 	free_recover_size(ls);
 fail:
@@ -1374,14 +1382,17 @@ static void gdlm_unmount(struct gfs2_sbd *sdp)
 
 	/* mounted_lock and control_lock will be purged in dlm recovery */
 release:
-	if (ls->ls_dlm) {
-		dlm_release_lockspace(ls->ls_dlm, 2);
-		ls->ls_dlm = NULL;
-	}
-
+	gdlm_ls_release(ls);
 	free_recover_size(ls);
 }
 
+static void gdlm_release(struct gfs2_sbd *sdp)
+{
+	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
+
+	gdlm_ls_release(ls);
+}
+
 static const match_table_t dlm_tokens = {
 	{ Opt_jid, "jid=%d"},
 	{ Opt_id, "id=%d"},
@@ -1396,6 +1407,7 @@ const struct lm_lockops gfs2_dlm_ops = {
 	.lm_first_done = gdlm_first_done,
 	.lm_recovery_result = gdlm_recovery_result,
 	.lm_unmount = gdlm_unmount,
+	.lm_release = gdlm_release,
 	.lm_put_lock = gdlm_put_lock,
 	.lm_lock = gdlm_lock,
 	.lm_cancel = gdlm_cancel,
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 7f8410d8fdc1..ef25ed884db2 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1075,8 +1075,12 @@ static int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent)
 void gfs2_lm_unmount(struct gfs2_sbd *sdp)
 {
 	const struct lm_lockops *lm = sdp->sd_lockstruct.ls_ops;
-	if (likely(!gfs2_withdrawn(sdp)) && lm->lm_unmount)
+	if (likely(!gfs2_withdrawn(sdp)) && lm->lm_unmount) {
 		lm->lm_unmount(sdp);
+	} else {
+		if (lm->lm_release)
+			lm->lm_release(sdp);
+	}
 }
 
 static int wait_on_journal(struct gfs2_sbd *sdp)
-- 
2.27.0