[Ocfs2-devel] [PATCH 1/3] ocfs2: avoid inode removed while nfsd access it

[Junxiao Bi <junxiao.bi@oracle.com>]

When nfsd is getting file dentry using handle or parent dentry of some
dentry, one cluster lock is used to avoid inode removed from other node,
but it still could be removed from local node, so use a rw lock to avoid
this.

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
---
 fs/ocfs2/dlmglue.c | 17 ++++++++++++++---
 fs/ocfs2/ocfs2.h   |  1 +
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 152a0fc4e905..c5e84314e203 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -678,15 +678,17 @@ static void ocfs2_rename_lock_res_init(struct ocfs2_lock_res *res,
 				   &ocfs2_rename_lops, osb);
 }
 
-static void ocfs2_nfs_sync_lock_res_init(struct ocfs2_lock_res *res,
-					 struct ocfs2_super *osb)
+static void ocfs2_nfs_sync_lock_res_init(struct ocfs2_super *osb)
 {
+	struct ocfs2_lock_res *res = &osb->osb_nfs_sync_lockres;
+
 	/* nfs_sync lockres doesn't come from a slab so we call init
 	 * once on it manually.  */
 	ocfs2_lock_res_init_once(res);
 	ocfs2_build_lock_name(OCFS2_LOCK_TYPE_NFS_SYNC, 0, 0, res->l_name);
 	ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_NFS_SYNC,
 				   &ocfs2_nfs_sync_lops, osb);
+	init_rwsem(&osb->nfs_sync_rwlock);
 }
 
 void ocfs2_trim_fs_lock_res_init(struct ocfs2_super *osb)
@@ -2855,6 +2857,11 @@ int ocfs2_nfs_sync_lock(struct ocfs2_super *osb, int ex)
 	if (ocfs2_is_hard_readonly(osb))
 		return -EROFS;
 
+	if (ex)
+		down_write(&osb->nfs_sync_rwlock);
+	else
+		down_read(&osb->nfs_sync_rwlock);
+
 	if (ocfs2_mount_local(osb))
 		return 0;
 
@@ -2873,6 +2880,10 @@ void ocfs2_nfs_sync_unlock(struct ocfs2_super *osb, int ex)
 	if (!ocfs2_mount_local(osb))
 		ocfs2_cluster_unlock(osb, lockres,
 				     ex ? LKM_EXMODE : LKM_PRMODE);
+	if (ex)
+		up_write(&osb->nfs_sync_rwlock);
+	else
+		up_read(&osb->nfs_sync_rwlock);
 }
 
 int ocfs2_trim_fs_lock(struct ocfs2_super *osb,
@@ -3340,7 +3351,7 @@ int ocfs2_dlm_init(struct ocfs2_super *osb)
 local:
 	ocfs2_super_lock_res_init(&osb->osb_super_lockres, osb);
 	ocfs2_rename_lock_res_init(&osb->osb_rename_lockres, osb);
-	ocfs2_nfs_sync_lock_res_init(&osb->osb_nfs_sync_lockres, osb);
+	ocfs2_nfs_sync_lock_res_init(osb);
 	ocfs2_orphan_scan_lock_res_init(&osb->osb_orphan_scan.os_lockres, osb);
 
 	osb->cconn = conn;
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index ee5d98516212..2dd71d626196 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -395,6 +395,7 @@ struct ocfs2_super
 	struct ocfs2_lock_res osb_super_lockres;
 	struct ocfs2_lock_res osb_rename_lockres;
 	struct ocfs2_lock_res osb_nfs_sync_lockres;
+	struct rw_semaphore nfs_sync_rwlock;
 	struct ocfs2_lock_res osb_trim_fs_lockres;
 	struct mutex obs_trim_fs_mutex;
 	struct ocfs2_dlm_debug *osb_dlm_debug;
-- 
2.20.1 (Apple Git-117)