From e1e0eb43ce1fd7bbdd9590715623cb3799896434 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Tue, 14 May 2019 13:54:41 +0300 Subject: [PATCH] btrfs: Ensure btrfs_init_dev_replace_tgtdev sees up to date values btrfs_init_dev_replace_tgtdev reads certain values from the source device (such as commit_total_bytes) which are updated during transaction commit. Currently this function is called before committing any pending transaction, leading to possibly reading outdated values. Fix this by moving the function below the transaction commit, at this point the EXCL_OP bit it set hence once transaction is complete the total size of the device cannot be changed (it's usually changed by resize/remove ops which are blocked). Fixes: 9e271ae27e44 ("Btrfs: kernel operation should come after user input has been verified") Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/dev-replace.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index eb8b5cb2c40d..149e6139182b 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -414,11 +414,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, return -ETXTBSY; } - ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name, - src_device, &tgt_device); - if (ret) - return ret; - /* * Here we commit the transaction to make sure commit_total_bytes * of all the devices are updated. @@ -432,6 +427,11 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, return PTR_ERR(trans); } + ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name, + src_device, &tgt_device); + if (ret) + return ret; + need_unlock = true; down_write(&dev_replace->rwsem); switch (dev_replace->replace_state) {