diff mbox series

[v2,2/2] ceph: do not release the global snaprealm until unmounting

Message ID 20220223010456.267425-3-xiubli@redhat.com
State New
Headers show
Series ceph: create the global dummy snaprealm once | expand

Commit Message

Xiubo Li Feb. 23, 2022, 1:04 a.m. UTC 
From: Xiubo Li <xiubli@redhat.com>

The global snaprealm would be created and then destroyed immediately
every time when updating it.

URL: https://tracker.ceph.com/issues/54362
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/mds_client.c         |  2 +-
 fs/ceph/snap.c               | 13 +++++++++++--
 fs/ceph/super.h              |  2 +-
 include/linux/ceph/ceph_fs.h |  3 ++-
 4 files changed, 15 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 65bd43d4cafc..b3b8f6299176 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4866,7 +4866,7 @@  void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
 	mutex_unlock(&mdsc->mutex);
 
 	ceph_cleanup_snapid_map(mdsc);
-	ceph_cleanup_empty_realms(mdsc);
+	ceph_cleanup_global_and_empty_realms(mdsc);
 
 	cancel_work_sync(&mdsc->cap_reclaim_work);
 	cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 66a1a92cf579..cc9097c27052 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -121,7 +121,11 @@  static struct ceph_snap_realm *ceph_create_snap_realm(
 	if (!realm)
 		return ERR_PTR(-ENOMEM);
 
-	atomic_set(&realm->nref, 1);    /* for caller */
+	/* Do not release the global dummy snaprealm until unmouting */
+	if (ino == CEPH_INO_GLOBAL_SNAPREALM)
+		atomic_set(&realm->nref, 2);
+	else
+		atomic_set(&realm->nref, 1);
 	realm->ino = ino;
 	INIT_LIST_HEAD(&realm->children);
 	INIT_LIST_HEAD(&realm->child_item);
@@ -261,9 +265,14 @@  static void __cleanup_empty_realms(struct ceph_mds_client *mdsc)
 	spin_unlock(&mdsc->snap_empty_lock);
 }
 
-void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc)
+void ceph_cleanup_global_and_empty_realms(struct ceph_mds_client *mdsc)
 {
+	struct ceph_snap_realm *global_realm;
+
 	down_write(&mdsc->snap_rwsem);
+	global_realm = __lookup_snap_realm(mdsc, CEPH_INO_GLOBAL_SNAPREALM);
+	if (global_realm)
+		ceph_put_snap_realm(mdsc, global_realm);
 	__cleanup_empty_realms(mdsc);
 	up_write(&mdsc->snap_rwsem);
 }
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index baac800a6d11..250aefecd628 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -942,7 +942,7 @@  extern void ceph_handle_snap(struct ceph_mds_client *mdsc,
 			     struct ceph_msg *msg);
 extern int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
 				  struct ceph_cap_snap *capsnap);
-extern void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc);
+extern void ceph_cleanup_global_and_empty_realms(struct ceph_mds_client *mdsc);
 
 extern struct ceph_snapid_map *ceph_get_snapid_map(struct ceph_mds_client *mdsc,
 						   u64 snap);
diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
index f14f9bc290e6..86bf82dbd8b8 100644
--- a/include/linux/ceph/ceph_fs.h
+++ b/include/linux/ceph/ceph_fs.h
@@ -28,7 +28,8 @@ 
 
 
 #define CEPH_INO_ROOT   1
-#define CEPH_INO_CEPH   2       /* hidden .ceph dir */
+#define CEPH_INO_CEPH   2            /* hidden .ceph dir */
+#define CEPH_INO_GLOBAL_SNAPREALM  3 /* global dummy snaprealm */
 
 /* arbitrary limit on max # of monitors (cluster of 3 is typical) */
 #define CEPH_MAX_MON   31