0001-Fix-snapshot-automount-race-cause-EREMOTE.patch

From f3ac39e16ff20b635e7d8773a4a32a357893aa7f Mon Sep 17 00:00:00 2001
From: Chunwei Chen <david.chen@osnexus.com>
Date: Fri, 11 Dec 2015 15:24:34 -0800
Subject: [PATCH] Fix snapshot automount race cause EREMOTE

When a concorrent mount finishes just before calling to
zfsctl_snapshot_ismounted, if we return EISDIR, the VFS will return with
EREMOTE. We should instead just return 0, so VFS may retry and would likely
notice the dentry is alreadly mounted. This will be inline with when usermode
helper return EBUSY.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
---
 module/zfs/zfs_ctldir.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/module/zfs/zfs_ctldir.c b/module/zfs/zfs_ctldir.c
index b03c4e5..84466b8 100644
--- a/module/zfs/zfs_ctldir.c
+++ b/module/zfs/zfs_ctldir.c
@@ -1086,7 +1086,7 @@ zfsctl_snapshot_mount(struct path *path, int flags)
 	 * The snapshot may be manually mounted as many times as desired.
 	 */
 	if (zfsctl_snapshot_ismounted(full_name)) {
-		error = SET_ERROR(EISDIR);
+		error = 0;
 		goto error;
 	}
 
-- 
1.9.1