btrfs: revert fs_devices state on error of btrfs_init_new_device
When btrfs hits error after modifying fs_devices in
btrfs_init_new_device() (such as btrfs_add_dev_item() returns error), it
leaves everything as is, but frees allocated btrfs_device. As a result,
fs_devices->devices and fs_devices->alloc_list contain already freed
btrfs_device, leading to later use-after-free bug.
Error path also messes the things like ->num_devices. While they go back
to the original value by unscanning btrfs devices, it is safe to revert
them here.
Fixes: 79787eaab461 ("btrfs: replace many BUG_ONs with proper error handling")
Signed-off-by: Naohiro Aota <naota@elisp.net>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 7218a79..da86706 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2321,7 +2321,8 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
struct super_block *sb = fs_info->sb;
struct rcu_string *name;
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
- u64 tmp;
+ u64 orig_super_total_bytes;
+ u64 orig_super_num_devices;
int seeding_dev = 0;
int ret = 0;
bool unlocked = false;
@@ -2417,12 +2418,14 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
if (!blk_queue_nonrot(q))
fs_devices->rotating = 1;
- tmp = btrfs_super_total_bytes(fs_info->super_copy);
+ orig_super_total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
btrfs_set_super_total_bytes(fs_info->super_copy,
- round_down(tmp + device->total_bytes, fs_info->sectorsize));
+ round_down(orig_super_total_bytes + device->total_bytes,
+ fs_info->sectorsize));
- tmp = btrfs_super_num_devices(fs_info->super_copy);
- btrfs_set_super_num_devices(fs_info->super_copy, tmp + 1);
+ orig_super_num_devices = btrfs_super_num_devices(fs_info->super_copy);
+ btrfs_set_super_num_devices(fs_info->super_copy,
+ orig_super_num_devices + 1);
/* add sysfs device entry */
btrfs_sysfs_add_device_link(fs_devices, device);
@@ -2502,6 +2505,22 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
error_sysfs:
btrfs_sysfs_rm_device_link(fs_devices, device);
+ mutex_lock(&fs_info->fs_devices->device_list_mutex);
+ mutex_lock(&fs_info->chunk_mutex);
+ list_del_rcu(&device->dev_list);
+ list_del(&device->dev_alloc_list);
+ fs_info->fs_devices->num_devices--;
+ fs_info->fs_devices->open_devices--;
+ fs_info->fs_devices->rw_devices--;
+ fs_info->fs_devices->total_devices--;
+ fs_info->fs_devices->total_rw_bytes -= device->total_bytes;
+ atomic64_sub(device->total_bytes, &fs_info->free_chunk_space);
+ btrfs_set_super_total_bytes(fs_info->super_copy,
+ orig_super_total_bytes);
+ btrfs_set_super_num_devices(fs_info->super_copy,
+ orig_super_num_devices);
+ mutex_unlock(&fs_info->chunk_mutex);
+ mutex_unlock(&fs_info->fs_devices->device_list_mutex);
error_trans:
if (seeding_dev)
sb->s_flags |= SB_RDONLY;