kernel.git/fs/btrfs/zstd.c, branch master

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51Z

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28Z

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

btrfs: remove the old btrfs_compress_folios() infrastructure

2026-02-03T06:59:07Z

Since it's been replaced by btrfs_compress_bio(), remove all involved functions. Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: zstd: introduce zstd_compress_bio() helper

2026-02-03T06:59:06Z

The new helper has the following enhancements against the existing zstd_compress_folios() - Much smaller parameter list No more shared IN/OUT members, no need to pre-allocate a compressed_folios[] array. Just a workspace and compressed_bio pointer, everything we need can be extracted from that @cb pointer. - Ready-to-be-submitted compressed bio Although the caller still needs to do some common works like rounding up and zeroing the tailing part of the last fs block. Overall the workflow is the same as zstd_compress_folios(), but with some minor changes: - @start/@len is now constant For the current input file offset, use @start + @tot_in instead. The original change of @start and @len makes it pretty hard to know what value we're really comparing to. - No more @cur_len It's only utilized when switching input buffer. Directly use btrfs_calc_input_length() instead. Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: zstd: use folio_iter to handle zstd_decompress_bio()

2026-02-03T06:56:18Z

Currently zstd_decompress_bio() is using compressed_bio->compressed_folios[] array to grab each compressed folio. However cb->compressed_folios[] is just a pointer to each folio of the compressed bio, meaning we can just replace the compressed_folios[] array by just grabbing the folio inside the compressed bio. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add unlikely annotations to branches leading to EIO

2025-09-23T06:49:26Z

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, where EIO is one of them. Reviewed-by: Filipe Manana Signed-off-by: David Sterba

btrfs: prepare zstd to support bs > ps cases

2025-09-23T06:49:24Z

This involves converting the following functions to use proper folio sizes/shifts: - zstd_compress_folios() - zstd_decompress_bio() The function zstd_decompress() is already using block size correctly without using page size, thus it needs no modification. And since zstd compression is calling kmap_local_folio(), the existing code cannot handle large folios with HIGHMEM, as kmap_local_folio() requires us to handle one page range each time. I do not really think it's worth to spend time on some feature that will be deprecated eventually. So here just add an extra explicit rejection for bs > ps with HIGHMEM feature enabled kernels. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: prepare compression folio alloc/free for bs > ps cases

2025-09-23T06:49:24Z

This includes the following preparation for bs > ps cases: - Always alloc/free the folio directly if bs > ps This adds a new @fs_info parameter for btrfs_alloc_compr_folio(), thus affecting all compression algorithms. For btrfs_free_compr_folio() it needs no parameter for now, as we can use the folio size to skip the caching part. For now the change is just to passing a @fs_info into the function, all the folio size assumption is still based on page size. - Properly zero the last folio in compress_file_range() Since the compressed folios can be larger than a page, we need to properly zero the whole folio. - Use correct folio size for btrfs_add_compressed_bio_folios() Instead of page size, use the correct folio size. - Use correct folio size/shift for btrfs_compress_filemap_get_folio() As we are not only using simple page sized folios anymore. - Use correct folio size for btrfs_decompress() There is an ASSERT() making sure the decompressed range is no larger than a page, which will be triggered for bs > ps cases. - Skip readahead for compressed pages Similar to subpage cases. - Make btrfs_alloc_folio_array() to accept a new @order parameter - Add a helper to calculate the minimal folio size All those changes should not affect the existing bs <= ps handling. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: reduce compression workspace buffer space to block size

2025-09-23T06:49:16Z

Currently the compression workspace buffer size is always based on PAGE_SIZE, but btrfs has support subpage sized block size for some time. This means for one-shot compression algorithm like lzo, we're wasting quite some memory if the block size is smaller than page size, as the LZO only works on one block (thus one-shot). On 64K page sized systems with 4K block size, it means we only need at most 8K buffer space for lzo, but in reality we're allocating 64K buffer. So to reduce the memory usage, change all workspace buffer to base its size based on block size other than page size. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: rename btrfs_compress_op to btrfs_compress_levels

2025-09-23T06:49:16Z

Since all workspace managers are per-fs, there is no need nor no way to store them inside btrfs_compress_op::wsm anymore. With that said, we can do the following modifications: - Remove zstd_workspace_mananger::ops Zstd always grab the global btrfs_compress_op[]. - Remove btrfs_compress_op::wsm member - Rename btrfs_compress_op to btrfs_compress_levels This should make it more clear that btrfs_compress_levels structures are only to indicate the levels of each compress algorithm. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba