kernel/linux.git/fs/btrfs/relocation.c, branch v7.1.8

btrfs: free mapping node on duplicate reloc root insert

2026-08-03T09:25:27+00:00

[ Upstream commit 6a8269b6459ed870a8156c106a0f597383907872 ] __add_reloc_root() allocates a mapping_node before inserting it into rc->reloc_root_tree. If rb_simple_insert() finds an existing entry, it returns the existing rb_node and leaves the newly allocated node unlinked. The error path then returns -EEXIST without freeing the new node. Since the node was never inserted into reloc_root_tree, the later cleanup in put_reloc_control() cannot find it either. Free the newly allocated node before returning -EEXIST. The callers currently assert that -EEXIST should not happen, so this is a defensive cleanup for an unexpected duplicate insert path. If the path is ever reached, the local allocation should still be released. Fixes: 57a304cfd43b ("btrfs: do not panic in __add_reloc_root") Reviewed-by: Qu Wenruo Signed-off-by: Guanghui Yang <3497809730@qq.com> Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: fix root leak if its reloc root is unexpected in merge_reloc_roots()

2026-08-03T09:25:16+00:00

[ Upstream commit ce6050bafb4e33377dc17fcc357736bfc351180c ] If we have an unexpected reloc_root for our root, we jump to the out label but never drop the reference we obtained for root, resulting in a leak. Add a missing btrfs_put_root() call. Fixes: 24213fa46c70 ("btrfs: do proper error handling in merge_reloc_roots") Reviewed-by: Qu Wenruo Reviewed-by: Johannes Thumshirn Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: don't clobber errors in add_remap_tree_entries()

2026-04-21T02:01:43+00:00

In add_remap_tree_entries(), we only process a certain number of entries at a time, meaning we may need to loop. But because we weren't checking the return value of btrfs_insert_empty_items() within the loop, this meant that if the last iteration of the loop succeeded but a previous iteration failed, we were erroneously returning 0. Fix this by breaking the loop early if btrfs_insert_empty_items() fails. Fixes: b56f35560b82 ("btrfs: handle setting up relocation of block group with remap-tree") Signed-off-by: Mark Harmstone Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: apply first key check for readahead when possible

2026-04-21T02:01:24+00:00

Currently for tree block readahead we never pass a btrfs_tree_parent_check with @has_first_key set. Without @has_first_key set, btrfs will skip the following extra checks: - Header generation check This is a minor one. - Empty leaf/node checks This is more serious, for certain trees like the csum tree, they are allowed to be empty, thus an empty leaf can pass the tree checker. But if there is a parent node for such an empty leaf, it indicates corruption. Without @has_first_key set, we can no longer detect such a problem. In fact there is already a fuzzed image report that a corrupted csum leaf which has zero nritems but still has a parent node can trigger a BUG_ON() during csum deletion. However there are only two call sites of btrfs_readahead_tree_block(): - Inside relocate_tree_blocks() At this call site we are trying to grab the first key of the tree block, thus we are not able to pass a @first_key parameter. - Inside btrfs_readahead_node_child() This is the more common call site, where we have the parent node and want to readahead the child tree blocks. In this case we can easily grab the node key and pass it for checks. Add a new parameter @first_key to btrfs_readahead_tree_block() and pass the node key to it inside btrfs_readahead_node_child(). This should plug the gap in empty leaf detection during readahead. Link: https://lore.kernel.org/linux-btrfs/20260409071255.3358044-1-gality369@gmail.com/ Reviewed-by: David Sterba Signed-off-by: Qu Wenruo Signed-off-by: David Sterba

btrfs: abort transaction in do_remap_reloc_trans() on failure

2026-04-21T02:00:52+00:00

If one of the calls made by do_remap_reloc_trans() fails, we can leave the remap tree in an inconsistent state. Abort the transaction if this happens, to prevent the corrupt state from reaching the disk. Reviewed-by: Johannes Thumshirn Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: fix bytes_may_use leak in do_remap_reloc_trans()

2026-04-21T02:00:39+00:00

If the call to btrfs_reserve_extent() in do_remap_reloc_trans() returns a smaller extent than we asked for, currently we're not undoing the bytes_may_use change that we made. Fix this by calling btrfs_space_info_update_bytes_may_use() again for the difference. Fixes: fd6594b1446c ("btrfs: replace identity remaps with actual remaps when doing relocations") Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: fix bytes_may_use leak in move_existing_remap()

2026-04-21T02:00:32+00:00

If the call to btrfs_reserve_extent() in move_existing_remap() returns a smaller extent than we asked for, currently we're not undoing the bytes_may_use change that we made. Fix this by calling btrfs_space_info_update_bytes_may_use() again for the difference. Fixes: bbea42dfb91f ("btrfs: move existing remaps before relocating block group") Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: avoid starting new transaction and commit in relocate_block_group()

2026-04-07T16:55:55+00:00

We join a transaction with the goal of catching the current transaction and then commit it to get rid of pinned extents and reclaim free space, but a join can create a new transaction if there isn't any running, and if right before we did the join the current transaction happened to be committed by someone else (like the transaction kthread for example), we end up starting and committing a new transaction, causing rotation of the super block backup roots besides extra and useless IO. So instead of doing a transaction join followed by a commit, use the helper btrfs_commit_current_transaction() which ensures no transaction is created if there isn't any running. Reviewed-by: Boris Burkov Signed-off-by: Filipe Manana Signed-off-by: David Sterba

btrfs: remove redundant extent_buffer_uptodate() checks after read_tree_block()

2026-04-07T16:55:55+00:00

We have several places that call extent_buffer_uptodate() after reading a tree block with read_tree_block(), but that is redundant since we already call extent_buffer_uptodate() in the call chain of read_tree_block(): read_tree_block() btrfs_read_extent_buffer() read_extent_buffer_pages() returns -EIO if extent_buffer_uptodate() returns false So remove those redundant checks. Reviewed-by: Boris Burkov Signed-off-by: Filipe Manana Signed-off-by: David Sterba

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()