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 <[email protected]> --- fs/btrfs/disk-io.c | 4 ++++ fs/btrfs/volumes.c | 7 +++++++ 2 files changed, 11 insertions(+), 0 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index ef6865c..5a70096 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1412,6 +1412,7 @@ 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; @@ -1421,6 +1422,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits) break; } } + mutex_unlock(&info->fs_devices->device_list_mutex); return ret; } @@ -1434,6 +1436,7 @@ static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page) struct btrfs_fs_info *info; info = (struct btrfs_fs_info *)bdi->unplug_io_data; + mutex_lock(&info->fs_devices->device_list_mutex); list_for_each_entry(device, &info->fs_devices->devices, dev_list) { if (!device->bdev) continue; @@ -1442,6 +1445,7 @@ static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page) if (bdi->unplug_io_fn) bdi->unplug_io_fn(bdi, page); } + mutex_unlock(&info->fs_devices->device_list_mutex); } static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 69fc902..a672249 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -515,6 +515,7 @@ 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); @@ -529,6 +530,8 @@ 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; @@ -1449,7 +1452,11 @@ 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; -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
