kernel/linux.git/fs/btrfs/root-tree.c, branch v6.18.22

btrfs: add unlikely annotations to branches leading to transaction abort

2025-09-23T06:49:26+00:00

The unlikely() annotation is a static prediction hint that compiler may use to reorder code out of hot path. We use it elsewhere (namely tree-checker.c) for error branches that almost never happen. Transaction abort is one such error, the btrfs_abort_transaction() inlines code to check the state and print a warning, this ought to be out of the hot path. The most common pattern is when transaction abort is called after checking a return value and the control flow leads to a quick return. In other cases it may not be necessary to add unlikely() e.g. when the function returns anyway or the control flow is not changed noticeably. Reviewed-by: Filipe Manana Signed-off-by: David Sterba

btrfs: add unlikely annotations to branches leading to EUCLEAN

2025-09-23T06:49:26+00:00

btrfs: more trivial BTRFS_PATH_AUTO_FREE conversions

2025-09-23T06:49:26+00:00

Trivial pattern for the auto freeing with goto -> return conversions if possible. The following cases are considered trivial in this patch: 1. Cases where there are no operations between btrfs_free_path() and the function returns. 2. Cases where only simple cleanup operations (such as kfree(), kvfree(), clear_bit(), and fs_path_free()) are present between btrfs_free_path() and the function return. Signed-off-by: Sun YangKai Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: root-tree: remove unnecessary calls to btrfs_mark_buffer_dirty()

2025-01-13T13:53:20+00:00

We have several places explicitly calling btrfs_mark_buffer_dirty() but that is not necessarily since the target leaf came from a path that was obtained for a btree search function that modifies the btree, something like btrfs_insert_empty_item() or anything else that ends up calling btrfs_search_slot() with a value of 1 for its 'cow' argument. These just make the code more verbose, confusing and add a little extra overhead and well as increase the module's text size, so remove them. Reviewed-by: Johannes Thumshirn Signed-off-by: Filipe Manana Signed-off-by: David Sterba

btrfs: change root->root_key.objectid to btrfs_root_id()

2024-05-07T19:31:06+00:00

A comment from Filipe on one of my previous cleanups brought my attention to a new helper we have for getting the root id of a root, which makes it easier to read in the code. The changes where made with the following Coccinelle semantic patch: // @@ expression E,E1; @@ ( E->root_key.objectid = E1 | - E->root_key.objectid + btrfs_root_id(E) ) // Reviewed-by: Filipe Manana Signed-off-by: Josef Bacik Reviewed-by: David Sterba [ minor style fixups ] Signed-off-by: David Sterba

btrfs: qgroup: fix qgroup prealloc rsv leak in subvolume operations

2024-04-02T17:18:23+00:00

Create subvolume, create snapshot and delete subvolume all use btrfs_subvolume_reserve_metadata() to reserve metadata for the changes done to the parent subvolume's fs tree, which cannot be mediated in the normal way via start_transaction. When quota groups (squota or qgroups) are enabled, this reserves qgroup metadata of type PREALLOC. Once the operation is associated to a transaction, we convert PREALLOC to PERTRANS, which gets cleared in bulk at the end of the transaction. However, the error paths of these three operations were not implementing this lifecycle correctly. They unconditionally converted the PREALLOC to PERTRANS in a generic cleanup step regardless of errors or whether the operation was fully associated to a transaction or not. This resulted in error paths occasionally converting this rsv to PERTRANS without calling record_root_in_trans successfully, which meant that unless that root got recorded in the transaction by some other thread, the end of the transaction would not free that root's PERTRANS, leaking it. Ultimately, this resulted in hitting a WARN in CONFIG_BTRFS_DEBUG builds at unmount for the leaked reservation. The fix is to ensure that every qgroup PREALLOC reservation observes the following properties: 1. any failure before record_root_in_trans is called successfully results in freeing the PREALLOC reservation. 2. after record_root_in_trans, we convert to PERTRANS, and now the transaction owns freeing the reservation. This patch enforces those properties on the three operations. Without it, generic/269 with squotas enabled at mkfs time would fail in ~5-10 runs on my system. With this patch, it ran successfully 1000 times in a row. Fixes: e85fde5162bf ("btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations") CC: stable@vger.kernel.org # 6.1+ Reviewed-by: Qu Wenruo Signed-off-by: Boris Burkov Signed-off-by: David Sterba

btrfs: handle invalid root reference found in btrfs_find_root()

2024-03-04T15:24:47+00:00

The btrfs_find_root() looks up a root by a key, allowing to do an inexact search when key->offset is -1. It's never expected to find such item, as it would break allowed the range of a root id. Reviewed-by: Josef Bacik Reviewed-by: Anand Jain Signed-off-by: David Sterba

btrfs: handle root deletion lookup error in btrfs_del_root()

2024-03-04T15:24:47+00:00

We're deleting a root and looking it up by key does not succeed, this is an inconsistent state and we can't do anything. All callers handle errors and abort a transaction. Reviewed-by: Josef Bacik Reviewed-by: Anand Jain Signed-off-by: David Sterba

btrfs: remove unused included headers

2024-03-04T15:24:46+00:00

With help of neovim, LSP and clangd we can identify header files that are not actually needed to be included in the .c files. This is focused only on removal (with minor fixups), further cleanups are possible but will require doing the header files properly with forward declarations, minimized includes and include-what-you-use care. Reviewed-by: Josef Bacik Signed-off-by: David Sterba

btrfs: qgroup: add new quota mode for simple quotas

2023-10-12T14:44:10+00:00

Add a new quota mode called "simple quotas". It can be enabled by the existing quota enable ioctl via a new command, and sets an incompat bit, as the implementation of simple quotas will make backwards incompatible changes to the disk format of the extent tree. Signed-off-by: Boris Burkov Signed-off-by: David Sterba