[PATCH 3.12 167/181] Btrfs: fix NULL pointer crash of deleting a seed device

Jiri Slaby
2014-06-30T12:51:29Z

From: Liu Bo <bo.li.liu@oracle.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 29cc83f69c8338ff8fd1383c9be263d4bdf52d73 upstream.

Same as normal devices, seed devices should be initialized with
fs_info->dev_root as well, otherwise we'll get a NULL pointer crash.

Cc: Chris Murphy <lists@colorremedies.com>
Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
fs/btrfs/volumes.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 258cd6ec3bd2..f0f50531c6c3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6051,10 +6051,14 @@ void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
struct btrfs_device *device;

- mutex_lock(&fs_devices->device_list_mutex);
- list_for_each_entry(device, &fs_devices->devices, dev_list)
- device->dev_root = fs_info->dev_root;
- mutex_unlock(&fs_devices->device_list_mutex);
+ while (fs_devices) {
+ mutex_lock(&fs_devices->device_list_mutex);
+ list_for_each_entry(device, &fs_devices->devices, dev_list)
+ device->dev_root = fs_info->dev_root;
+ mutex_unlock(&fs_devices->device_list_mutex);
+
+ fs_devices = fs_devices->seed;
+ }
}

static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
--
2.0.0