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2026-05-16btrfs: swallow btrfs_record_squota_delta() ENOENTBoris Burkov1-2/+3
I thought that it was likely I could harden squota deletion to the point that it was impossible to end up with an extent accounted to a qgroup outliving its qgroup. Several recent bugs have made me re-consider that position. Ultimately, this is a tradeoff between short term stability and long term strictness, but I think given that there could be another layer of bugs behind the 2-3 I just fixed, I would feel much more confident in people using squotas if the risk was "your values can get a bit out of whack which you can fix by deleting stuff or disabling/re-enabling/repairing" vs "it will abort your filesystem". As the final nail in the coffin, the Meta production kernel was lacking earlier fixes from me and Qu regarding subvol qgroup lifetime, so this is what we have been testing at scale, so I think at least for now upstream should have the same extra layer of protection. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16btrfs: clamp to avoid squota underflowBoris Burkov1-2/+13
Simple quota accounting can undercount metadata tree block allocations in certain scenarios. When an undercounted subvolume is deleted and its tree blocks freed, the free deltas decrement rfer/excl past zero, wrapping the u64 to a value near U64_MAX. Once wrapped, can_delete_squota_qgroup() sees non-zero rfer and refuses to delete the qgroup. The qgroup becomes permanently orphaned in the quota tree, since there is no subvolume left to generate frees that would bring the counter back to zero. While we ultimately want to fix any mis-accounting at the source, it is also helpful and worthwhile to mitigate the damage by clamping rfer and excl to zero on underflow rather than allowing the u64 to wrap. This at least allows us to clean up the messed up qgroups on subvol deletion. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16btrfs: fix squota accounting during enable generationBoris Burkov1-4/+27
The first transaction that enables squotas is special and a bit tricky. We have to set BTRFS_FS_QUOTA_ENABLED after the transaction to avoid a deadlock, so any delayed refs that run before we set the bit are not squota accounted. For data this is fine, we don't get an owner_ref, so there is no real harm, it's as if the extent predated squotas. However for metadata, the tree block will have gen == enable_gen so when we free it later, we will decrement the squota accounting, which can result in an underflow. Before it is freed, btrfs check shows errors, as we have mismatched usage between the node generations/owners and the squota values. There are two angles to this fix: 1. For extents that come in delayed_refs that run during the enable_gen transaction, we must actually set enable_gen to the *next* transaction. That is the first transaction that we can really properly account in any way. 2. For extents that come in between the end of our transaction handle and the time we set the BTRFS_FS_QUOTA_ENABLED bit, we need an additional bit, BTRFS_FS_SQUOTA_ENABLING which only affects recording squota deltas, so we do pick up those extents. Otherwise, we would miss them, even for enable_gen + 1. Fixes: bd7c1ea3a302 ("btrfs: qgroup: check generation when recording simple quota delta") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16btrfs: check for subvolume before deleting squota qgroupBoris Burkov1-25/+25
The invariant that we want to maintain with subvolume qgroups is that the qgroup can only be deleted if there is no root. With squotas, we thought that it was sufficient to just check the usage, because we assumed that deleting a subvolume will drive it's qgroups usage to 0, and thus 0 usage implies no subvolume. However, this is false, for two reasons: - A subvol whose extents are all from before squotas was enabled. - A subvol that was created in this transaction and for which we have not yet run any delayed refs. In both cases, deleting the qgroup breaks the desired invariant and we are left with a subvolume with no qgroup but squotas are enabled. Fix this by unifying the deletion check logic between full qgroups and squotas. Squotas do all the same checks *and* the additional usage == 0 check, which is the one extra rule peculiar to squotas. Link: https://lore.kernel.org/linux-btrfs/adnBhWfJQ1n3hZC8@merlins.org/ Fixes: a8df35619948 ("btrfs: forbid deleting live subvol qgroup") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07btrfs: avoid GFP_ATOMIC allocations in qgroup free pathsLeo Martins1-2/+3
When qgroups are enabled, __btrfs_qgroup_release_data() and qgroup_free_reserved_data() pass an extent_changeset to btrfs_clear_record_extent_bits() to track how many bytes had their EXTENT_QGROUP_RESERVED bits cleared. Inside the extent IO tree spinlock, add_extent_changeset() calls ulist_add() with GFP_ATOMIC to record each changed range. If this allocation fails, it hits a BUG_ON and panics the kernel. However, both of these callers only read changeset.bytes_changed afterwards — the range_changed ulist is populated and immediately freed without ever being iterated. The GFP_ATOMIC allocation is entirely unnecessary for these paths. Introduce extent_changeset_init_bytes_only() which uses a sentinel value (EXTENT_CHANGESET_BYTES_ONLY) on the ulist's prealloc field to signal that only bytes_changed should be tracked. add_extent_changeset() checks for this sentinel and returns early after updating bytes_changed, skipping the ulist_add() call entirely. This eliminates the GFP_ATOMIC allocation and makes the BUG_ON unreachable for these paths. Callers that need range tracking (qgroup_reserve_data, qgroup_unreserve_range, btrfs_qgroup_check_reserved_leak) continue to use extent_changeset_init() and are unaffected. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Leo Martins <loemra.dev@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07btrfs: unexport btrfs_qgroup_reserve_meta()Filipe Manana1-2/+2
There's only one caller outside qgroup.c of btrfs_qgroup_reserve_meta() and we have btrfs_qgroup_reserve_meta_prealloc() is a wrapper around that function. Make that caller use btrfs_qgroup_reserve_meta_prealloc() and unexport btrfs_qgroup_reserve_meta(), simplifying the external API. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07btrfs: collapse __btrfs_qgroup_reserve_meta() into ↵Filipe Manana1-5/+6
btrfs_qgroup_reserve_meta_prealloc() Since __btrfs_qgroup_reserve_meta() is only called by btrfs_qgroup_reserve_meta_prealloc(), which is a simple inline wrapper, get rid of the later and rename __btrfs_qgroup_reserve_meta() to the later. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07btrfs: collapse __btrfs_qgroup_free_meta() into ↵Filipe Manana1-5/+7
btrfs_qgroup_free_meta_prealloc() Since __btrfs_qgroup_free_meta() is only called by btrfs_qgroup_free_meta_prealloc(), which is a simple inline wrapper, get rid of the later and rename __btrfs_qgroup_free_meta() to the later. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07btrfs: pass literal booleans to functions that take boolean argumentsFilipe Manana1-4/+2
We have several functions with parameters defined as booleans but then we have callers passing integers, 0 or 1, instead of false and true. While this isn't a bug since 0 and 1 are converted to false and true, it is odd and less readable. Change the callers to pass true and false literals instead. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07btrfs: remove redundant extent_buffer_uptodate() checks after read_tree_block()Filipe Manana1-4/+0
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 <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-03-21Merge tag 'for-7.0-rc4-tag' of ↵Linus Torvalds1-0/+8
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux 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()
2026-03-17btrfs: check for NULL root after calls to btrfs_extent_root()Filipe Manana1-0/+8
btrfs_extent_root() can return a NULL pointer in case the root we are looking for is not in the rb tree that tracks roots. So add checks to every caller that is missing such check to log a message and return an error. The same applies to callers of btrfs_block_group_root(), since it calls btrfs_extent_root(). Reported-by: Chris Mason <clm@meta.com> Link: https://lore.kernel.org/linux-btrfs/20260208161657.3972997-1-clm@meta.com/ Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-03-03Merge tag 'for-7.0-rc2-tag' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: "One-liner or short fixes for minor/moderate problems reported recently: - fixes or level adjustments of error messages - fix leaked transaction handles after aborted transactions, when using the remap tree feature - fix a few leaked chunk maps after errors - fix leaked page array in io_uring encoded read if an error occurs and the 'finished' is not called - fix double release of reserved extents when doing a range COW - don't commit super block when the filesystem is in shutdown state - fix squota accounting condition when checking members vs parent usage - other error handling fixes" * tag 'for-7.0-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: check block group lookup in remove_range_from_remap_tree() btrfs: fix transaction handle leaks in btrfs_last_identity_remap_gone() btrfs: fix chunk map leak in btrfs_map_block() after btrfs_translate_remap() btrfs: fix chunk map leak in btrfs_map_block() after btrfs_chunk_map_num_copies() btrfs: fix compat mask in error messages in btrfs_check_features() btrfs: print correct subvol num if active swapfile prevents deletion btrfs: fix warning in scrub_verify_one_metadata() btrfs: fix objectid value in error message in check_extent_data_ref() btrfs: fix incorrect key offset in error message in check_dev_extent_item() btrfs: fix error message order of parameters in btrfs_delete_delayed_dir_index() btrfs: don't commit the super block when unmounting a shutdown filesystem btrfs: free pages on error in btrfs_uring_read_extent() btrfs: fix referenced/exclusive check in squota_check_parent_usage() btrfs: remove pointless WARN_ON() in cache_save_setup() btrfs: convert log messages to error level in btrfs_replay_log() btrfs: remove btrfs_handle_fs_error() after failure to recover log trees btrfs: remove redundant warning message in btrfs_check_uuid_tree() btrfs: change warning messages to error level in open_ctree() btrfs: fix a double release on reserved extents in cow_one_range() btrfs: handle discard errors in in btrfs_finish_extent_commit()
2026-02-26btrfs: fix referenced/exclusive check in squota_check_parent_usage()Boris Burkov1-1/+1
We compared rfer_cmpr against excl_cmpr_sum instead of rfer_cmpr_sum which is confusing. I expect that rfer_cmpr == excl_cmpr in squota, but it is much better to be consistent in case of any surprises or bugs. Reported-by: Chris Mason <clm@meta.com> Link: https://lore.kernel.org/linux-btrfs/cover.1764796022.git.boris@bur.io/T/#mccb231643ffd290b44a010d4419474d280be5537 Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-21Convert 'alloc_obj' family to use the new default GFP_KERNEL argumentLinus Torvalds1-2/+2
This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21treewide: Replace kmalloc with kmalloc_obj for non-scalar typesKees Cook1-13/+12
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 <kees@kernel.org>
2026-02-18btrfs: fix invalid leaf access in btrfs_quota_enable() if ref key not foundFilipe Manana1-4/+7
If btrfs_search_slot_for_read() returns 1, it means we did not find any key greater than or equals to the key we asked for, meaning we have reached the end of the tree and therefore the path is not valid. If this happens we need to break out of the loop and stop, instead of continuing and accessing an invalid path. Fixes: 5223cc60b40a ("btrfs: drop the path before adding qgroup items when enabling qgroups") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: remove pointless out labels from qgroup.cFilipe Manana1-16/+10
Some functions (__del_qgroup_relation() and qgroup_trace_new_subtree_blocks()) have an 'out' label that does nothing but return, making it pointless. Simplify this by removing the label and returning instead of gotos plus setting the 'ret' variable. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: qgroup: return correct error when deleting qgroup relation itemFilipe Manana1-1/+3
If we fail to delete the second qgroup relation item, we end up returning success or -ENOENT in case the first item does not exist, instead of returning the error from the second item deletion. Fixes: 73798c465b66 ("btrfs: qgroup: Try our best to delete qgroup relations") Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: merge setting ret and return retDavid Sterba1-10/+4
In many places we have pattern: ret = ...; return ret; This can be simplified to a direct return, removing 'ret' if not otherwise needed. The places in self tests are not converted so we can add more test cases without changing surrounding code (extent-map-tests.c:test_case_4()). Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: relax squota parent qgroup deletion ruleBoris Burkov1-15/+35
Currently, with squotas, we do not allow removing a parent qgroup with no members if it still has usage accounted to it. This makes it really difficult to recover from accounting bugs, as we have no good way of getting back to 0 usage. Instead, allow deletion (it's safe at 0 members..) while still warning about the inconsistency by adding a squota parent check. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: check squota parent usage on membership changeBoris Burkov1-0/+39
We could have detected the quick inherit bug more directly if we had an extra warning about squota hierarchy consistency while modifying the hierarchy. In squotas, the parent usage always simply adds up to the sum of its children, so we can just check for that when changing membership and detect more accounting bugs. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2025-12-16btrfs: qgroup: update all parent qgroups when doing quick inheritQu Wenruo1-2/+16
[BUG] There is a bug that if a subvolume has multi-level parent qgroups, and is able to do a quick inherit, only the direct parent qgroup got updated: mkfs.btrfs -f -O quota $dev mount $dev $mnt btrfs subv create $mnt/subv1 btrfs qgroup create 1/100 $mnt btrfs qgroup create 2/100 $mnt btrfs qgroup assign 1/100 2/100 $mnt btrfs qgroup assign 0/256 1/100 $mnt btrfs qgroup show -p --sync $mnt Qgroupid Referenced Exclusive Parent Path -------- ---------- --------- ------ ---- 0/5 16.00KiB 16.00KiB - <toplevel> 0/256 16.00KiB 16.00KiB 1/100 subv1 1/100 16.00KiB 16.00KiB 2/100 2/100<1 member qgroup> 2/100 16.00KiB 16.00KiB - <0 member qgroups> btrfs subv snap -i 1/100 $mnt/subv1 $mnt/snap1 btrfs qgroup show -p --sync $mnt Qgroupid Referenced Exclusive Parent Path -------- ---------- --------- ------ ---- 0/5 16.00KiB 16.00KiB - <toplevel> 0/256 16.00KiB 16.00KiB 1/100 subv1 0/257 16.00KiB 16.00KiB 1/100 snap1 1/100 32.00KiB 32.00KiB 2/100 2/100<1 member qgroup> 2/100 16.00KiB 16.00KiB - <0 member qgroups> # Note that 2/100 is not updated, and qgroup numbers are inconsistent umount $mnt [CAUSE] If the snapshot source subvolume belongs to a parent qgroup, and the new snapshot target is also added to the new same parent qgroup, we allow a quick update without marking qgroup inconsistent. But that quick update only update the parent qgroup, without checking if there is any more parent qgroups. [FIX] Iterate through all parent qgroups during the quick inherit. Reported-by: Boris Burkov <boris@bur.io> Fixes: b20fe56cd285 ("btrfs: qgroup: allow quick inherit if snapshot is created and added to the same parent") Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-12-16btrfs: fix qgroup_snapshot_quick_inherit() squota bugBoris Burkov1-0/+3
qgroup_snapshot_quick_inherit() detects conditions where the snapshot destination would land in the same parent qgroup as the snapshot source subvolume. In this case we can avoid costly qgroup calculations and just add the nodesize of the new snapshot to the parent. However, in the case of squotas this is actually a double count, and also an undercount for deeper qgroup nestings. The following annotated script shows the issue: btrfs quota enable --simple "$mnt" # Create 2-level qgroup hierarchy btrfs qgroup create 2/100 "$mnt" # Q2 (level 2) btrfs qgroup create 1/100 "$mnt" # Q1 (level 1) btrfs qgroup assign 1/100 2/100 "$mnt" # Create base subvolume btrfs subvolume create "$mnt/base" >/dev/null base_id=$(btrfs subvolume show "$mnt/base" | grep 'Subvolume ID:' | awk '{print $3}') # Create intermediate snapshot and add to Q1 btrfs subvolume snapshot "$mnt/base" "$mnt/intermediate" >/dev/null inter_id=$(btrfs subvolume show "$mnt/intermediate" | grep 'Subvolume ID:' | awk '{print $3}') btrfs qgroup assign "0/$inter_id" 1/100 "$mnt" # Create working snapshot with --inherit (auto-adds to Q1) # src=intermediate (in only Q1) # dst=snap (inheriting only into Q1) # This double counts the 16k nodesize of the snapshot in Q1, and # undercounts it in Q2. btrfs subvolume snapshot -i 1/100 "$mnt/intermediate" "$mnt/snap" >/dev/null snap_id=$(btrfs subvolume show "$mnt/snap" | grep 'Subvolume ID:' | awk '{print $3}') # Fully complete snapshot creation sync # Delete working snapshot # Q1 and Q2 will lose the full snap usage btrfs subvolume delete "$mnt/snap" >/dev/null # Delete intermediate and remove from Q1 # Q1 and Q2 will lose the full intermediate usage btrfs qgroup remove "0/$inter_id" 1/100 "$mnt" btrfs subvolume delete "$mnt/intermediate" >/dev/null # Q1 should be at 0, but still has 16k. Q2 is "correct" at 0 (for now...) # Trigger cleaner, wait for deletions mount -o remount,sync=1 "$mnt" btrfs subvolume sync "$mnt" "$snap_id" btrfs subvolume sync "$mnt" "$inter_id" # Remove Q1 from Q2 # Frees 16k more from Q2, underflowing it to 16EiB btrfs qgroup remove 1/100 2/100 "$mnt" # And show the bad state: btrfs qgroup show -pc "$mnt" Qgroupid Referenced Exclusive Parent Child Path -------- ---------- --------- ------ ----- ---- 0/5 16.00KiB 16.00KiB - - <toplevel> 0/256 16.00KiB 16.00KiB - - base 1/100 16.00KiB 16.00KiB - - <0 member qgroups> 2/100 16.00EiB 16.00EiB - - <0 member qgroups> Fix this by simply not doing this quick inheritance with squotas. I suspect that it is also wrong in normal qgroups to not recurse up the qgroup tree in the quick inherit case, though other consistency checks will likely fix it anyway. Fixes: b20fe56cd285 ("btrfs: qgroup: allow quick inherit if snapshot is created and added to the same parent") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2025-12-09Revert "btrfs: add ASSERTs on prealloc in qgroup functions"Qu Wenruo1-23/+4
This reverts commit 252877a8701530fde861a4f27710c1e718e97caa. Commit 252877a87015 ("btrfs: add ASSERTs on prealloc in qgroup functions") tries to remove the kfree() on preallocated qgroup during several call sites, but this cannot work as intended: - btrfs_quota_enable() - btrfs_create_qgroup() If add_qgroup_item() failed, we go out_free_path() and at that time prealloc is not yet utilized and will trigger the new ASSERT(). - btrfs_qgroup_inherit() If qgroup_auto_inherit() failed, prealloc is not yet utilized and will trigger the new ASSERT() Reported-by: syzbot+b44d4a4885bc82af2a06@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/69369331.a70a0220.38f243.009e.GAE@google.com/ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-25btrfs: remaining BTRFS_PATH_AUTO_FREE conversionsDavid Sterba1-89/+53
Do the remaining btrfs_path conversion to the auto cleaning, this seems to be the last one. Most of the conversions are trivial, only adding the declaration and removing the freeing, or changing the goto patterns to return. There are some functions with many changes, like __btrfs_free_extent(), btrfs_remove_from_free_space_tree() or btrfs_add_to_free_space_tree() but it still follows the same pattern. Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24btrfs: use bool type for btrfs_path members used as booleansFilipe Manana1-2/+2
Many fields of struct btrfs_path are used as booleans but their type is an unsigned int (of one 1 bit width to save space). Change the type to bool keeping the :1 suffix so that they combine with the previous u8 fields in order to save space. This makes the code more clear by using explicit true/false and more in line with the preferred style, preserving the size of the structure. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24btrfs: add ASSERTs on prealloc in qgroup functionsMiquel Sabaté Solà1-4/+23
The prealloc variable in these functions is always initialized to NULL. Whenever we allocate memory for it, if it fails then NULL is preserved, otherwise we delegate the ownership of the pointer to add_qgroup_rb() and set it right after to NULL. Since in any case the pointer ends up being NULL at the end of its usage, we can safely remove calls to kfree() for it, while adding an ASSERT as an extra check. Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24btrfs: apply the AUTO_K(V)FREE macros throughout the codeMiquel Sabaté Solà1-2/+1
Apply the AUTO_KFREE and AUTO_KVFREE macros wherever it makes sense. Since this macro is expected to improve code readability, it has been avoided in places where the lifetime of objects wasn't easy to follow and a cleanup attribute would've made things worse; or when the cleanup section of a function involved many other things and thus there was no readability impact anyways. This change has also not been applied in extremely short functions where readability was clearly not an issue. Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24btrfs: use the key format macros when printing keysFilipe Manana1-4/+2
Change all locations that print a key to use the new macros to print them in order to ensure a consistent style and avoid repetitive code. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-10-30btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relationShardul Bankar1-1/+3
When btrfs_add_qgroup_relation() is called with invalid qgroup levels (src >= dst), the function returns -EINVAL directly without freeing the preallocated qgroup_list structure passed by the caller. This causes a memory leak because the caller unconditionally sets the pointer to NULL after the call, preventing any cleanup. The issue occurs because the level validation check happens before the mutex is acquired and before any error handling path that would free the prealloc pointer. On this early return, the cleanup code at the 'out' label (which includes kfree(prealloc)) is never reached. In btrfs_ioctl_qgroup_assign(), the code pattern is: prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL); ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc); prealloc = NULL; // Always set to NULL regardless of return value ... kfree(prealloc); // This becomes kfree(NULL), does nothing When the level check fails, 'prealloc' is never freed by either the callee or the caller, resulting in a 64-byte memory leak per failed operation. This can be triggered repeatedly by an unprivileged user with access to a writable btrfs mount, potentially exhausting kernel memory. Fix this by freeing prealloc before the early return, ensuring prealloc is always freed on all error paths. Fixes: 4addc1ffd67a ("btrfs: qgroup: preallocate memory before adding a relation") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Shardul Bankar <shardulsb08@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23btrfs: add unlikely annotations to branches leading to transaction abortDavid Sterba1-12/+12
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 <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23btrfs: add unlikely annotations to branches leading to EIODavid Sterba1-2/+2
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 <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23btrfs: add unlikely annotations to branches leading to EUCLEANDavid Sterba1-7/+7
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 EUCLEAN (a corruption) is one of them. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-22btrfs: convert several int parameters to boolDavid Sterba1-1/+1
We're almost done cleaning misused int/bool parameters. Convert a bunch of them, found by manual grepping. Note that btrfs_sync_fs() needs an int as it's mandated by the struct super_operations prototype. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-02btrfs: fix squota compressed stats leakBoris Burkov1-2/+4
The following workload on a squota enabled fs: btrfs subvol create mnt/subvol # ensure subvol extents get accounted sync btrfs qgroup create 1/1 mnt btrfs qgroup assign mnt/subvol 1/1 mnt btrfs qgroup delete mnt/subvol # make the cleaner thread run btrfs filesystem sync mnt sleep 1 btrfs filesystem sync mnt btrfs qgroup destroy 1/1 mnt will fail with EBUSY. The reason is that 1/1 does the quick accounting when we assign subvol to it, gaining its exclusive usage as excl and excl_cmpr. But then when we delete subvol, the decrement happens via record_squota_delta() which does not update excl_cmpr, as squotas does not make any distinction between compressed and normal extents. Thus, we increment excl_cmpr but never decrement it, and are unable to delete 1/1. The two possible fixes are to make squota always mirror excl and excl_cmpr or to make the fast accounting separately track the plain and cmpr numbers. The latter felt cleaner to me so that is what I opted for. Fixes: 1e0e9d5771c3 ("btrfs: add helper for recording simple quota deltas") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2025-08-07btrfs: fix iteration bug in __qgroup_excl_accounting()Boris Burkov1-2/+1
__qgroup_excl_accounting() uses the qgroup iterator machinery to update the account of one qgroups usage for all its parent hierarchy, when we either add or remove a relation and have only exclusive usage. However, there is a small bug there: we loop with an extra iteration temporary qgroup called `cur` but never actually refer to that in the body of the loop. As a result, we redundantly account the same usage to the first qgroup in the list. This can be reproduced in the following way: mkfs.btrfs -f -O squota <dev> mount <dev> <mnt> btrfs subvol create <mnt>/sv dd if=/dev/zero of=<mnt>/sv/f bs=1M count=1 sync btrfs qgroup create 1/100 <mnt> btrfs qgroup create 2/200 <mnt> btrfs qgroup assign 1/100 2/200 <mnt> btrfs qgroup assign 0/256 1/100 <mnt> btrfs qgroup show <mnt> and the broken result is (note the 2MiB on 1/100 and 0Mib on 2/100): Qgroupid Referenced Exclusive Path -------- ---------- --------- ---- 0/5 16.00KiB 16.00KiB <toplevel> 0/256 1.02MiB 1.02MiB sv Qgroupid Referenced Exclusive Path -------- ---------- --------- ---- 0/5 16.00KiB 16.00KiB <toplevel> 0/256 1.02MiB 1.02MiB sv 1/100 2.03MiB 2.03MiB 2/100<1 member qgroup> 2/100 0.00B 0.00B <0 member qgroups> With this fix, which simply re-uses `qgroup` as the iteration variable, we see the expected result: Qgroupid Referenced Exclusive Path -------- ---------- --------- ---- 0/5 16.00KiB 16.00KiB <toplevel> 0/256 1.02MiB 1.02MiB sv Qgroupid Referenced Exclusive Path -------- ---------- --------- ---- 0/5 16.00KiB 16.00KiB <toplevel> 0/256 1.02MiB 1.02MiB sv 1/100 1.02MiB 1.02MiB 2/100<1 member qgroup> 2/100 1.02MiB 1.02MiB <0 member qgroups> The existing fstests did not exercise two layer inheritance so this bug was missed. I intend to add that testing there, as well. Fixes: a0bdc04b0732 ("btrfs: qgroup: use qgroup_iterator in __qgroup_excl_accounting()") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-22btrfs: remove btrfs_clear_extent_bits()Filipe Manana1-2/+2
It's just a simple wrapper around btrfs_clear_extent_bit() that passes a NULL for its last argument (a cached extent state record), plus there is not counter part - we have a btrfs_set_extent_bit() but we do not have a btrfs_set_extent_bits() (plural version). So just remove it and make all callers use btrfs_clear_extent_bit() directly. Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-22btrfs: qgroup: fix qgroup create ioctl returning success after quotas disabledFilipe Manana1-3/+0
When quotas are disabled qgroup ioctls are supposed to return -ENOTCONN, but the qgroup create ioctl stopped doing that when it races with a quota disable operation, returning 0 instead. This change of behaviour happened in commit 6ed05643ddb1 ("btrfs: create qgroup earlier in snapshot creation"). The issue happens as follows: 1) Task A enters btrfs_ioctl_qgroup_create(), qgroups are enabled and so qgroup_enabled() returns true since fs_info->quota_root is not NULL; 2) Task B enters btrfs_ioctl_quota_ctl() -> btrfs_quota_disable() and disables qgroups, so now fs_info->quota_root is NULL; 3) Task A enters btrfs_create_qgroup() and calls btrfs_qgroup_mode(), which returns BTRFS_QGROUP_MODE_DISABLED since quotas are disabled, and then btrfs_create_qgroup() returns 0 to the caller, which makes the ioctl return 0 instead of -ENOTCONN. The check for fs_info->quota_root and returning -ENOTCONN if it's NULL is made only after the call btrfs_qgroup_mode(). Fix this by moving the check for disabled quotas with btrfs_qgroup_mode() into transaction.c:create_pending_snapshot(), so that we don't abort the transaction if btrfs_create_qgroup() returns -ENOTCONN and quotas are disabled. Fixes: 6ed05643ddb1 ("btrfs: create qgroup earlier in snapshot creation") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-22btrfs: qgroup: set quota enabled bit if quota disable fails flushing ↵Filipe Manana1-2/+5
reservations Before waiting for the rescan worker to finish and flushing reservations, we clear the BTRFS_FS_QUOTA_ENABLED flag from fs_info. If we fail flushing reservations we leave with the flag not set which is not correct since quotas are still enabled - we must set back the flag on error paths, such as when we fail to start a transaction, except for error paths that abort a transaction. The reservation flushing happens very early before we do any operation that actually disables quotas and before we start a transaction, so set back BTRFS_FS_QUOTA_ENABLED if it fails. Fixes: af0e2aab3b70 ("btrfs: qgroup: flush reservations during quota disable") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-22btrfs: qgroup: remove no longer used fs_info->qgroup_ulistFilipe Manana1-30/+1
It's not used anymore after commit 091344508249 ("btrfs: qgroup: use qgroup_iterator in qgroup_convert_meta()"), so remove it. Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-22btrfs: qgroup: fix race between quota disable and quota rescan ioctlFilipe Manana1-7/+24
There's a race between a task disabling quotas and another running the rescan ioctl that can result in a use-after-free of qgroup records from the fs_info->qgroup_tree rbtree. This happens as follows: 1) Task A enters btrfs_ioctl_quota_rescan() -> btrfs_qgroup_rescan(); 2) Task B enters btrfs_quota_disable() and calls btrfs_qgroup_wait_for_completion(), which does nothing because at that point fs_info->qgroup_rescan_running is false (it wasn't set yet by task A); 3) Task B calls btrfs_free_qgroup_config() which starts freeing qgroups from fs_info->qgroup_tree without taking the lock fs_info->qgroup_lock; 4) Task A enters qgroup_rescan_zero_tracking() which starts iterating the fs_info->qgroup_tree tree while holding fs_info->qgroup_lock, but task B is freeing qgroup records from that tree without holding the lock, resulting in a use-after-free. Fix this by taking fs_info->qgroup_lock at btrfs_free_qgroup_config(). Also at btrfs_qgroup_rescan() don't start the rescan worker if quotas were already disabled. Reported-by: cen zhang <zzzccc427@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CAFRLqsV+cMDETFuzqdKSHk_FDm6tneea45krsHqPD6B3FetLpQ@mail.gmail.com/ CC: stable@vger.kernel.org # 6.1+ Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: qgroup: avoid memory allocation if qgroups are not enabledFilipe Manana1-2/+3
At btrfs_qgroup_inherit() we allocate a qgroup record even if qgroups are not enabled, which is unnecessary overhead and can result in subvolume creation to fail with -ENOMEM, as create_subvol() calls this function. Improve on this by making btrfs_qgroup_inherit() check if qgroups are enabled earlier and return if they are not, avoiding the unnecessary memory allocation and taking some locks. Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: qgroup: remove pointless error check for add_qgroup_rb() callFilipe Manana1-5/+0
The add_qgroup_rb() function never returns an error pointer anymore since commit 8d54518b5e52 ("btrfs: qgroup: pre-allocate btrfs_qgroup to reduce GFP_ATOMIC usage"), so checking for an error pointer result at btrfs_quota_enable() is pointless. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: add btrfs prefix to is_fstree() and make it return boolFilipe Manana1-12/+13
This is an exported function and therefore it should have a 'btrfs_' prefix, to make it clear it's btrfs specific, avoid future name collisions with code outside btrfs, and make its naming consistent with most other btrfs exported functions. So add a 'btrfs_' prefix to it and make it return bool instead of int, since all we need is to return true or false. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-o