[PATCH 3.14 095/110] Btrfs: fix NULL pointer crash of deleting a seed device

Greg Kroah-Hartman
2014-06-28T17:50:54Z

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

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/volumes.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6057,10 +6057,14 @@ void btrfs_init_devices_late(struct btrf
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)