From: Liu Bo <bo.li.liu@oracle.com>
Date: Wed, 14 Nov 2012 14:35:30 +0000 (+0000)
Subject: Btrfs: protect devices list with its mutex
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d25628bdd66aedd6e07729d8dc6c8ee846d66d72;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

Btrfs: protect devices list with its mutex

Since we've kill the bigger one volume_mutex, we need to add devices
list mutex back.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
---

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index db79fb7e7e91..92e586bc8004 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1681,16 +1681,17 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 	filemap_write_and_wait(bdev->bd_inode->i_mapping);
 
 	devices = &root->fs_info->fs_devices->devices;
-	/*
-	 * we have the volume lock, so we don't need the extra
-	 * device list mutex while reading the list here.
-	 */
+
+	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
 	list_for_each_entry(device, devices, dev_list) {
 		if (device->bdev == bdev) {
 			ret = -EEXIST;
+			mutex_unlock(
+				&root->fs_info->fs_devices->device_list_mutex);
 			goto error;
 		}
 	}
+	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
 	device = kzalloc(sizeof(*device), GFP_NOFS);
 	if (!device) {