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authorMiao Xie <miaox@cn.fujitsu.com>2014-09-03 17:35:42 +0400
committerChris Mason <clm@fb.com>2014-09-18 00:38:43 +0400
commitadbbb8631beda8e4e5d2c964b8b47e04cfa0a2ae (patch)
tree4ee13e368464d455415919b0d52ca75defa4ff3e /fs/btrfs
parent2196d6e8a71fc901e31c1d81581fc6cc6c64913e (diff)
downloadlinux-adbbb8631beda8e4e5d2c964b8b47e04cfa0a2ae.tar.xz
Btrfs: fix unprotected device list access when cloning fs devices
We can build a new filesystem based a seed filesystem, and we need clone the fs devices when we open the new filesystem. But someone might clear the seed flag of the seed filesystem, then mount that filesystem and remove some device. If we mount the new filesystem, we might access a device list which was being changed when we clone the fs devices. Fix it. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/volumes.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 105c5fe004db..d28e1761fdeb 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -583,6 +583,7 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
if (IS_ERR(fs_devices))
return fs_devices;
+ mutex_lock(&orig->device_list_mutex);
fs_devices->total_devices = orig->total_devices;
/* We have held the volume lock, it is safe to get the devices. */
@@ -611,8 +612,10 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
device->fs_devices = fs_devices;
fs_devices->num_devices++;
}
+ mutex_unlock(&orig->device_list_mutex);
return fs_devices;
error:
+ mutex_unlock(&orig->device_list_mutex);
free_fs_devices(fs_devices);
return ERR_PTR(-ENOMEM);
}