1 files changed, 17 insertions, 1 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 102d79575895..f11b7dc16e9d 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -945,9 +945,20 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
         if (!file)
                 goto out;
 
+        /*
+         * If we don't hold exclusive handle for the device, upgrade to it
+         * here to avoid changing device under exclusive owner.
+         */
+        if (!(mode & FMODE_EXCL)) {
+                bdgrab(bdev);
+                error = blkdev_get(bdev, mode | FMODE_EXCL, loop_set_fd);
+                if (error)
+                        goto out_putf;
+        }
+
         error = mutex_lock_killable(&loop_ctl_mutex);
         if (error)
-                goto out_putf;
+                goto out_bdev;
 
         error = -EBUSY;
         if (lo->lo_state != Lo_unbound)
@@ -1012,10 +1023,15 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
         mutex_unlock(&loop_ctl_mutex);
         if (partscan)
                 loop_reread_partitions(lo, bdev);
+        if (!(mode & FMODE_EXCL))
+                blkdev_put(bdev, mode | FMODE_EXCL);
         return 0;
 
 out_unlock:
         mutex_unlock(&loop_ctl_mutex);
+out_bdev:
+        if (!(mode & FMODE_EXCL))
+                blkdev_put(bdev, mode | FMODE_EXCL);
 out_putf:
         fput(file);
 out: