From 3eb423442483d454937cdc8853e58c399ffe5514 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Mon, 21 Nov 2022 10:23:24 +0000 Subject: [PATCH] btrfs: remove outdated logic from overwrite_item() and add assertion As of commit 193df6245704 ("btrfs: search for last logged dir index if it's not cached in the inode"), the overwrite_item() function is always called for a root that is from a fs/subvolume tree. In other words, now it's only used during log replay to modify a fs/subvolume tree. Therefore we can remove the logic that checks if we are dealing with a log tree at overwrite_item(). So remove that logic, replacing it with an assertion and document that if we ever need to support a log root there, we will need to clone the leaf from the fs/subvolume tree and then release it before modifying the log tree, which is needed to avoid a potential deadlock, similar to the one recently fixed by a patch with the subject: "btrfs: do not modify log tree while holding a leaf from fs tree locked" Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/tree-log.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index bcc8717f51fd..a3c43f0b1c95 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -391,11 +391,16 @@ static int overwrite_item(struct btrfs_trans_handle *trans, int save_old_i_size = 0; unsigned long src_ptr; unsigned long dst_ptr; - int overwrite_root = 0; bool inode_item = key->type == BTRFS_INODE_ITEM_KEY; - if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) - overwrite_root = 1; + /* + * This is only used during log replay, so the root is always from a + * fs/subvolume tree. In case we ever need to support a log root, then + * we'll have to clone the leaf in the path, release the path and use + * the leaf before writing into the log tree. See the comments at + * copy_items() for more details. + */ + ASSERT(root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID); item_size = btrfs_item_size(eb, slot); src_ptr = btrfs_item_ptr_offset(eb, slot); @@ -548,8 +553,7 @@ insert: goto no_copy; } - if (overwrite_root && - S_ISDIR(btrfs_inode_mode(eb, src_item)) && + if (S_ISDIR(btrfs_inode_mode(eb, src_item)) && S_ISDIR(btrfs_inode_mode(path->nodes[0], dst_item))) { save_old_i_size = 1; saved_i_size = btrfs_inode_size(path->nodes[0], -- 2.11.0