Merge remote-tracking branch 'lsk/v3.10/topic/gator' into linux-linaro-lsk

[firefly-linux-kernel-4.4.55.git] / fs / gfs2 / ops_fstype.c

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 60ede2a0f43fbc498201cc3262da939110eac0bb..f7dd3b4f8ab0dc6d903ad6f78c72bbc19f850260 100644 (file)
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1317,8 +1317,18 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
        if (IS_ERR(s))
                goto error_bdev;
 
-       if (s->s_root)
+       if (s->s_root) {
+               /*
+                * s_umount nests inside bd_mutex during
+                * __invalidate_device().  blkdev_put() acquires
+                * bd_mutex and can't be called under s_umount.  Drop
+                * s_umount temporarily.  This is safe as we're
+                * holding an active reference.
+                */
+               up_write(&s->s_umount);
                blkdev_put(bdev, mode);
+               down_write(&s->s_umount);
+       }
 
        memset(&args, 0, sizeof(args));
        args.ar_quota = GFS2_QUOTA_DEFAULT;