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| author |   Miao Xie <miaox@cn.fujitsu.com> | 2014-09-03 21:35:43 +0800 |
|---|---|---|
| committer |   Chris Mason <clm@fb.com> | 2014-09-17 13:38:44 -0700 |
| commit | 67a2c45ee7f4f250458279a2e1244679c5d9735c (patch) | |
| tree | 0f1806d2aead6af9629bb701101b75b28863b986 /fs/btrfs/dev-replace.c | |
| parent | Btrfs: fix unprotected device list access when cloning fs devices (diff) | |
| download | linux-dev-67a2c45ee7f4f250458279a2e1244679c5d9735c.tar.xz linux-dev-67a2c45ee7f4f250458279a2e1244679c5d9735c.zip | |
Btrfs: fix use-after-free problem of the device during device replace
The problem is:
Task0(device scan task) Task1(device replace task)
scan_one_device()
mutex_lock(&uuid_mutex)
device = find_device()
mutex_lock(&device_list_mutex)
lock_chunk()
rm_and_free_source_device
unlock_chunk()
mutex_unlock(&device_list_mutex)
check device
Destroying the target device if device replace fails also has the same problem.
We fix this problem by locking uuid_mutex during destroying source device or
target device, just like the device remove operation.
It is a temporary solution, we can fix this problem and make the code more
clear by atomic counter in the future.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/dev-replace.c')
| -rw-r--r-- | fs/btrfs/dev-replace.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index aa4c82863c73..e9cbbdb72978 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -509,6 +509,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, ret = btrfs_commit_transaction(trans, root); WARN_ON(ret); + mutex_lock(&uuid_mutex); /* keep away write_all_supers() during the finishing procedure */ mutex_lock(&root->fs_info->fs_devices->device_list_mutex); mutex_lock(&root->fs_info->chunk_mutex); @@ -536,6 +537,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, btrfs_dev_replace_unlock(dev_replace); mutex_unlock(&root->fs_info->chunk_mutex); mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + mutex_unlock(&uuid_mutex); if (tgt_device) btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device); mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); @@ -591,6 +593,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, */ mutex_unlock(&root->fs_info->chunk_mutex); mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + mutex_unlock(&uuid_mutex); /* write back the superblocks */ trans = btrfs_start_transaction(root, 0); |