kernel/linux.git/fs/btrfs/compression.c, branch v7.0.10

Merge tag 'for-7.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2026-03-21T15:42:17+00:00

Pull btrfs fixes from David Sterba: "Another batch of fixes for problems that have been identified by tools analyzing code or by fuzzing. Most of them are short, two patches fix the same thing in many places so the diffs are bigger. - handle potential NULL pointer errors after attempting to read extent and checksum trees - prevent ENOSPC when creating many qgroups by ioctls in the same transaction - encoded write ioctl fixes (with 64K page and 4K block size): - fix unexpected bio length - do not let compressed bios and pages interfere with page cache - compression fixes on setups with 64K page and 4K block size: fix folio length assertions (zstd and lzo) - remap tree fixes: - make sure to hold block group reference while moving it - handle early exit when moving block group to unused list - handle deleted subvolumes with inconsistent state of deletion progress" * tag 'for-7.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: reject root items with drop_progress and zero drop_level btrfs: check block group before marking it unused in balance_remap_chunks() btrfs: hold block group reference during entire move_existing_remap() btrfs: fix an incorrect ASSERT() condition inside lzo_decompress_bio() btrfs: fix an incorrect ASSERT() condition inside zstd_decompress_bio() btrfs: do not touch page cache for encoded writes btrfs: fix a bug that makes encoded write bio larger than expected btrfs: reserve enough transaction items for qgroup ioctls btrfs: check for NULL root after calls to btrfs_csum_root() btrfs: check for NULL root after calls to btrfs_extent_root()

btrfs: do not touch page cache for encoded writes

2026-03-17T10:43:07+00:00

[BUG] When running btrfs/284, the following ASSERT() will be triggered with 64K page size and 4K fs block size: assertion failed: folio_test_writeback(folio) :: 0, in subpage.c:476 ------------[ cut here ]------------ kernel BUG at subpage.c:476! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP CPU: 4 UID: 0 PID: 2313 Comm: kworker/u37:2 Tainted: G OE 6.19.0-rc8-custom+ #185 PREEMPT(voluntary) Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022 Workqueue: btrfs-endio simple_end_io_work [btrfs] pc : btrfs_subpage_clear_writeback+0x148/0x160 [btrfs] lr : btrfs_subpage_clear_writeback+0x148/0x160 [btrfs] Call trace: btrfs_subpage_clear_writeback+0x148/0x160 [btrfs] (P) btrfs_folio_clamp_clear_writeback+0xb4/0xd0 [btrfs] end_compressed_writeback+0xe0/0x1e0 [btrfs] end_bbio_compressed_write+0x1e8/0x218 [btrfs] btrfs_bio_end_io+0x108/0x258 [btrfs] simple_end_io_work+0x68/0xa8 [btrfs] process_one_work+0x168/0x3f0 worker_thread+0x25c/0x398 kthread+0x154/0x250 ret_from_fork+0x10/0x20 ---[ end trace 0000000000000000 ]--- [CAUSE] The offending bio is from an encoded write, where the compressed data is directly written as a data extent, without touching the page cache. However the encoded write still utilizes the regular buffered write path for compressed data, by setting the compressed_bio::writeback flag. When that flag is set, at end_bbio_compressed_write() btrfs will go clearing the writeback flag of the folios in the page cache. However for bs < ps cases, the subpage helper has one extra check to make sure the folio has a writeback flag set in the first place. But since it's an encoded write, we never go through page cache, thus the folio has no writeback flag and triggers the ASSERT(). [FIX] Do not set compressed_bio::writeback flag for encoded writes, and change the ASSERT() in btrfs_submit_compressed_write() to make sure that flag is not set. Fixes: e1bc83f8b157 ("btrfs: get rid of compressed_folios[] usage for encoded writes") Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba

btrfs: fix a bug that makes encoded write bio larger than expected

2026-03-17T10:43:07+00:00

[BUG] When running btrfs/284 with 64K page size and 4K fs block size, the following ASSERT() can be triggered: assertion failed: cb->bbio.bio.bi_iter.bi_size == disk_num_bytes :: 0, in inode.c:9991 ------------[ cut here ]------------ kernel BUG at inode.c:9991! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP CPU: 5 UID: 0 PID: 6787 Comm: btrfs Tainted: G OE 6.19.0-rc8-custom+ #1 PREEMPT(voluntary) Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022 pc : btrfs_do_encoded_write+0x9b0/0x9c0 [btrfs] lr : btrfs_do_encoded_write+0x9b0/0x9c0 [btrfs] Call trace: btrfs_do_encoded_write+0x9b0/0x9c0 [btrfs] (P) btrfs_do_write_iter+0x1d8/0x208 [btrfs] btrfs_ioctl_encoded_write+0x3c8/0x6d0 [btrfs] btrfs_ioctl+0xeb0/0x2b60 [btrfs] __arm64_sys_ioctl+0xac/0x110 invoke_syscall.constprop.0+0x64/0xe8 el0_svc_common.constprop.0+0x40/0xe8 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x1b8 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1a4/0x1a8 Code: 91180021 90001080 9111a000 94039d54 (d4210000) ---[ end trace 0000000000000000 ]--- [CAUSE] After commit e1bc83f8b157 ("btrfs: get rid of compressed_folios[] usage for encoded writes"), the encoded write is changed to copy the content from the iov into a folio, and queue the folio into the compressed bio. However we always queue the full folio into the compressed bio, which can make the compressed bio larger than the on-disk extent, if the folio size is larger than the fs block size. Although we have an ASSERT() to catch such problem, for kernels without CONFIG_BTRFS_ASSERT, such larger than expected bio will just be submitted, possibly overwrite the next data extent, causing data corruption. [FIX] Instead of blindly queuing the full folio into the compressed bio, only queue the rounded up range, which is the old behavior before that offending commit. This also means we no longer need to zero the tailing range until the folio end (but still to the block boundary), as such range will not be submitted anyway. And since we're here, add a final ASSERT() into btrfs_submit_compressed_write() as the last safety net for kernels with btrfs assertions enabled Fixes: e1bc83f8b157 ("btrfs: get rid of compressed_folios[] usage for encoded writes") Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba

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

2026-02-22T01:09:51+00:00

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

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

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: get rid of compressed_bio::compressed_folios[]

2026-02-03T06:59:07+00:00

Now there is no one utilizing that member, we can safely remove it along with compressed_bio::nr_folios member. The size is reduced from 352 to 336 bytes on x86_64. Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: get rid of compressed_folios[] usage for encoded writes

2026-02-03T06:59:07+00:00

Currently only encoded writes utilized btrfs_submit_compressed_write(), which utilized compressed_bio::compressed_folios[] array. Change the only call site to call the new helper, btrfs_alloc_compressed_write(), to allocate a compressed bio, then queue needed folios into that bio, and finally call btrfs_submit_compressed_write() to submit the compressed bio. This change has one hidden benefit, previously we used btrfs_alloc_folio_array() for the folios of btrfs_submit_compressed_read(), which doesn't utilize the compression page pool for bs == ps cases. Now we call btrfs_alloc_compr_folio() which will benefit from the page pool. The other obvious benefit is that we no longer need to allocate an array to hold all those folios, thus one less error path. Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: get rid of compressed_folios[] usage for compressed read

2026-02-03T06:59:07+00:00

Currently btrfs_submit_compressed_read() still uses compressed_bio::compressed_folios[] array. Change it to allocate each folio and queue them into the compressed bio so that we do not need to allocate that array. Considering how small each compressed read bio is (less than 128KiB), we do not benefit that much from btrfs_alloc_folio_array() anyway, while we may benefit more from btrfs_alloc_compr_folio() by using the global folio pool. So changing from btrfs_alloc_folio_array() to btrfs_alloc_compr_folio() in a loop should still be fine. This removes one error path, and paves the way to completely remove compressed_folios[] array. Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: remove the old btrfs_compress_folios() infrastructure

2026-02-03T06:59:07+00:00

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: switch to btrfs_compress_bio() interface for compressed writes

2026-02-03T06:59:07+00:00

This switch has the following benefits: - A single structure to handle all compression No more extra members like compressed_folios[] nor compress_type, all those members. This means the structure of async_extent is much smaller. - Simpler error handling A single cleanup_compressed_bio() will handle everything, no extra compressed_folios[] array to bother. Some extra notes: - Compressed folios releasing Now we go bio_for_each_folio_all() loop to release the folios of the bio. This will work for both the old compressed_folios[] array and the new pure bio method. For old compressed_folios[], all folios of that array is queued into the bio, thus releasing the folios from the bio is the same as releasing each folio of that array. We just need to be sure no double releasing from the array and bio. For the new pure bio method, that array is NULL, just usual folio releasing of the bio. The only extra note is for end_bbio_compressed_read(), as the folios are allocated using btrfs_alloc_folio_array(), thus the folios should only be released by regular folio_put(), not btrfs_free_compr_folio(). - Rounding up the bio to block size We cannot simply increase bi_size, as that will not increase the length of the last bvec. Thus we have to properly add the last part into the bio. This will be done by the helper, round_up_last_block(). The reason we do not round those bios up at compression time is to get the unaligned compressed size, so that they can be utilized for inline extents. If we round the bios up at *_compress_bio(), then every compressed bio will be larger than or equal to one fs block, resulting no inline compressed extent. Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba