From a0fecc23718aa9ef020b8c86173a0b783ed37dcf Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 20 Mar 2018 23:44:50 +0100 Subject: [PATCH] btrfs: remove wrong use of volume_mutex from btrfs_dev_replace_start The volume mutex does not protect against anything in this case, the comment about scrub is right but not related to locking and looks confusing. The comment in btrfs_find_device_missing_or_by_path is wrong and confusing too. The device_list_mutex is not held here to protect device lookup, but in this case device replace cannot run in parallel with device removal (due to exclusive op protection), so we don't need further locking here. Reviewed-by: Anand Jain Signed-off-by: David Sterba --- fs/btrfs/dev-replace.c | 7 +------ fs/btrfs/volumes.c | 4 ---- 2 files changed, 1 insertion(+), 10 deletions(-) diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 9fe7be7fdbef..d097701d494d 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -414,18 +414,13 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, struct btrfs_device *tgt_device = NULL; struct btrfs_device *src_device = NULL; - /* the disk copy procedure reuses the scrub code */ - mutex_lock(&fs_info->volume_mutex); ret = btrfs_find_device_by_devspec(fs_info, srcdevid, srcdev_name, &src_device); - if (ret) { - mutex_unlock(&fs_info->volume_mutex); + if (ret) return ret; - } ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name, src_device, &tgt_device); - mutex_unlock(&fs_info->volume_mutex); if (ret) return ret; diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 07706c0a5781..9e5d27dd00b7 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2218,10 +2218,6 @@ int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info, struct btrfs_device *tmp; devices = &fs_info->fs_devices->devices; - /* - * It is safe to read the devices since the volume_mutex - * is held by the caller. - */ list_for_each_entry(tmp, devices, dev_list) { if (test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &tmp->dev_state) && !tmp->bdev) { -- 2.11.0