From f232ab04f65bb757f2d992a074a46df85c8f1797 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Tue, 14 May 2019 13:54:43 +0300 Subject: [PATCH] btrfs: Explicitly reserve space for devreplace item Part of device replace involves writing an item to the device root containing information about pending replace operations. Currently space for this item is not being explicitly reserved so this works thanks to presence of global reserve. While not fatal it's not a good practice. Let's be explicit about space requirement of device replace and reserve space when starting the transaction. Reviewed-by: Johannes Thumshirn Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/dev-replace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 94f000b0ca79..45c5ba7d80ed 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -477,8 +477,8 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); - /* force writing the updated state information to disk */ - trans = btrfs_start_transaction(root, 0); + /* Commit dev_replace state and reserve 1 item for it. */ + trans = btrfs_start_transaction(root, 1); if (IS_ERR(trans)) { ret = PTR_ERR(trans); down_write(&dev_replace->rwsem);