diff options
| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2011-04-20 10:07:30 +0000 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2011-05-23 13:24:42 -0400 |
| commit | c9513edb0079f97749c2ac00c887a22c4ba44792 (patch) | |
| tree | 6b34bd7cdf5dcd882e61bf4912ae10b4de3b87dd | |
| parent | 4f6c9328c6c0d8558907f16579a9d47815abef80 (diff) | |
Btrfs: fix the race between reading and updating devices
On btrfs_congested_fn and __unplug_io_fn paths, we should hold
device_list_mutex to avoid remove/add device path to
update fs_devices->devices
On __btrfs_close_devices and btrfs_prepare_sprout paths, the devices in
fs_devices->devices or fs_devices->devices is updated, so we should hold
the mutex to avoid the reader side to reach them
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
| -rw-r--r-- | fs/btrfs/disk-io.c | 2 | ||||
| -rw-r--r-- | fs/btrfs/volumes.c | 7 |
2 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 64b289690f9..4e53a4fc467 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1410,6 +1410,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits) struct btrfs_device *device; struct backing_dev_info *bdi; + mutex_lock(&info->fs_devices->device_list_mutex); list_for_each_entry(device, &info->fs_devices->devices, dev_list) { if (!device->bdev) continue; @@ -1419,6 +1420,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits) break; } } + mutex_unlock(&info->fs_devices->device_list_mutex); return ret; } diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 290100fc47b..43c4f09e441 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -481,6 +481,7 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices) if (--fs_devices->opened > 0) return 0; + mutex_lock(&fs_devices->device_list_mutex); list_for_each_entry(device, &fs_devices->devices, dev_list) { if (device->bdev) { blkdev_put(device->bdev, device->mode); @@ -495,6 +496,8 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices) device->writeable = 0; device->in_fs_metadata = 0; } + mutex_unlock(&fs_devices->device_list_mutex); + WARN_ON(fs_devices->open_devices); WARN_ON(fs_devices->rw_devices); fs_devices->opened = 0; @@ -1415,7 +1418,11 @@ static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans, INIT_LIST_HEAD(&seed_devices->devices); INIT_LIST_HEAD(&seed_devices->alloc_list); mutex_init(&seed_devices->device_list_mutex); + + mutex_lock(&root->fs_info->fs_devices->device_list_mutex); list_splice_init(&fs_devices->devices, &seed_devices->devices); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list); list_for_each_entry(device, &seed_devices->devices, dev_list) { device->fs_devices = seed_devices; |