kernel/linux.git/fs/btrfs/extent_map.h, branch linux-7.1.y

btrfs: headers cleanup to remove unnecessary local includes

2025-11-24T21:34:52+00:00

[BUG] When I tried to remove btrfs_bio::fs_info and use btrfs_bio::inode to grab the fs_info, the header "btrfs_inode.h" is needed to access the full btrfs_inode structure. Then btrfs will fail to compile. [CAUSE] There is a recursive including chain: "bio.h" -> "btrfs_inode.h" -> "extent_map.h" -> "compression.h" -> "bio.h" That recursive including is causing problems for btrfs. [ENHANCEMENT] To reduce the risk of recursive including: - Remove unnecessary local includes from btrfs headers Either the included header is pulled in by other headers, or is completely unnecessary. - Remove btrfs local includes if the header only requires a pointer In that case let the implementing C file to pull the required header. This is especially important for headers like "btrfs_inode.h" which pulls in a lot of other btrfs headers, thus it's a mine field of recursive including. - Remove unnecessary temporary structure definition Either if we have included the header defining the structure, or completely unused. Now including "btrfs_inode.h" inside "bio.h" is completely fine, although "btrfs_inode.h" still includes "extent_map.h", but that header only includes "fs.h", no more chain back to "bio.h". Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: rename remaining exported extent map functions

2025-05-15T12:30:45+00:00

Rename all the exported functions from extent_map.h that don't have a 'btrfs_' prefix in their names, so that they are consistent with all the other functions, to make it clear they are btrfs specific functions and to avoid potential name collisions in the future with functions defined elsewhere in the kernel. Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: rename functions to allocate and free extent maps

2025-05-15T12:30:45+00:00

These functions are exported and don't have a 'btrfs_' prefix in their names, which goes against coding style conventions. Rename them to have such prefix, making it clear they are from btrfs and avoiding potential collisions in the future with functions defined elsewhere outside btrfs. Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: rename extent map functions to get block start, end and check if in tree

2025-05-15T12:30:45+00:00

btrfs: rename exported extent map compression functions

2025-05-15T12:30:45+00:00

btrfs: make the extent map shrinker run asynchronously as a work queue job

2024-11-11T13:34:17+00:00

Currently the extent map shrinker is run synchronously for kswapd tasks that end up calling the fs shrinker (fs/super.c:super_cache_scan()). This has some disadvantages and for some heavy workloads with memory pressure it can cause some delays and stalls that make a machine unresponsive for some periods. This happens because: 1) We can have several kswapd tasks on machines with multiple NUMA zones, and running the extent map shrinker concurrently can cause high contention on some spin locks, namely the spin locks that protect the radix tree that tracks roots, the per root xarray that tracks open inodes and the list of delayed iputs. This not only delays the shrinker but also causes high CPU consumption and makes the task running the shrinker monopolize a core, resulting in the symptoms of an unresponsive system. This was noted in previous commits such as commit ae1e766f623f ("btrfs: only run the extent map shrinker from kswapd tasks"); 2) The extent map shrinker's iteration over inodes can often be slow, even after changing the data structure that tracks open inodes for a root from a red black tree (up to kernel 6.10) to an xarray (kernel 6.10+). The transition to the xarray while it made things a bit faster, it's still somewhat slow - for example in a test scenario with 10000 inodes that have no extent maps loaded, the extent map shrinker took between 5ms to 8ms, using a release, non-debug kernel. Iterating over the extent maps of an inode can also be slow if have an inode with many thousands of extent maps, since we use a red black tree to track and search extent maps. So having the extent map shrinker run synchronously adds extra delay for other things a kswapd task does. So make the extent map shrinker run asynchronously as a job for the system unbounded workqueue, just like what we do for data and metadata space reclaim jobs. Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Signed-off-by: David Sterba

btrfs: do not directly include rwlock_types.h

2024-07-11T13:33:22+00:00

There is already an error inside that header: #if !defined(__LINUX_SPINLOCK_TYPES_H) # error "Do not include directly, include spinlock_types.h" #endif Thankfully it never get triggered as some other headers have already included spinlock_types.h. However clangd would still do a proper warning on that if only extent_map.h is opened. Fix it by using spinlock_types.h instead. Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: cleanup recursive include of the same header

2024-07-11T13:33:22+00:00

We have several headers that are including themselves, triggering clangd warnings. Such includes are caused by commit 602035d7fecf ("btrfs: add forward declarations and headers, part 2"). Just remove such unnecessary include. Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: remove extent_map::block_start member

2024-07-11T13:33:21+00:00

The member extent_map::block_start can be calculated from extent_map::disk_bytenr + extent_map::offset for regular extents. And otherwise just extent_map::disk_bytenr. And this is already validated by the validate_extent_map(). Now we can remove the member. However there is a special case in btrfs_create_dio_extent() where we for NOCOW/PREALLOC ordered extents cannot directly use the resulting btrfs_file_extent, as btrfs_split_ordered_extent() cannot handle them yet. So for that call site, we pass file_extent->disk_bytenr + file_extent->num_bytes as disk_bytenr for the ordered extent, and 0 for offset. Reviewed-by: Johannes Thumshirn Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: remove extent_map::block_len member

2024-07-11T13:33:20+00:00

The extent_map::block_len is either extent_map::len (non-compressed extent) or extent_map::disk_num_bytes (compressed extent). Since we already have sanity checks to do the cross-checks between the new and old members, we can drop the old extent_map::block_len now. For most call sites, they can manually select extent_map::len or extent_map::disk_num_bytes, since most if not all of them have checked if the extent is compressed. Reviewed-by: Johannes Thumshirn Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba