linux/fs/btrfs
Filipe Manana 505a948d05 btrfs: do not delete unused block group if it may be used soon
commit f4a9f21941 upstream.

Before deleting a block group that is in the list of unused block groups
(fs_info->unused_bgs), we check if the block group became used before
deleting it, as extents from it may have been allocated after it was added
to the list.

However even if the block group was not yet used, there may be tasks that
have only reserved space and have not yet allocated extents, and they
might be relying on the availability of the unused block group in order
to allocate extents. The reservation works first by increasing the
"bytes_may_use" field of the corresponding space_info object (which may
first require flushing delayed items, allocating a new block group, etc),
and only later a task does the actual allocation of extents.

For metadata we usually don't end up using all reserved space, as we are
pessimistic and typically account for the worst cases (need to COW every
single node in a path of a tree at maximum possible height, etc). For
data we usually reserve the exact amount of space we're going to allocate
later, except when using compression where we always reserve space based
on the uncompressed size, as compression is only triggered when writeback
starts so we don't know in advance how much space we'll actually need, or
if the data is compressible.

So don't delete an unused block group if the total size of its space_info
object minus the block group's size is less then the sum of used space and
space that may be used (space_info->bytes_may_use), as that means we have
tasks that reserved space and may need to allocate extents from the block
group. In this case, besides skipping the deletion, re-add the block group
to the list of unused block groups so that it may be reconsidered later,
in case the tasks that reserved space end up not needing to allocate
extents from it.

Allowing the deletion of the block group while we have reserved space, can
result in tasks failing to allocate metadata extents (-ENOSPC) while under
a transaction handle, resulting in a transaction abort, or failure during
writeback for the case of data extents.

CC: stable@vger.kernel.org # 6.0+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:24:47 +01:00
..
tests btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
accessors.c btrfs: add eb to btrfs_node_key_ptr_offset 2022-12-05 18:00:58 +01:00
accessors.h btrfs: use helper sizeof_field in struct accessors 2023-08-21 14:52:13 +02:00
acl.c fs: port acl to mnt_idmap 2023-01-19 09:24:28 +01:00
acl.h fs: port ->set_acl() to pass mnt_idmap 2023-01-19 09:24:27 +01:00
async-thread.c btrfs: use alloc_ordered_workqueue() to create ordered workqueues 2023-06-19 13:59:30 +02:00
async-thread.h btrfs: use alloc_ordered_workqueue() to create ordered workqueues 2023-06-19 13:59:30 +02:00
backref.c btrfs: fix unwritten extent buffer after snapshotting a new subvolume 2023-10-23 17:17:30 +02:00
backref.h btrfs: fix unwritten extent buffer after snapshotting a new subvolume 2023-10-23 17:17:30 +02:00
bio.c btrfs: add an ordered_extent pointer to struct btrfs_bio 2023-06-19 13:59:36 +02:00
bio.h btrfs: add an ordered_extent pointer to struct btrfs_bio 2023-06-19 13:59:36 +02:00
block-group.c btrfs: do not delete unused block group if it may be used soon 2024-02-23 09:24:47 +01:00
block-group.h btrfs: add and use helper to check if block group is used 2024-02-23 09:24:47 +01:00
block-rsv.c btrfs: account block group tree when calculating global reserve size 2023-07-20 19:22:54 +02:00
block-rsv.h btrfs: move btrfs_check_trunc_cache_free_space into block-rsv.c 2023-06-19 13:59:24 +02:00
btrfs_inode.h btrfs: reduce the number of arguments to btrfs_run_delalloc_range 2023-08-21 14:52:14 +02:00
check-integrity.c btrfs: rename __btrfs_map_block to btrfs_map_block 2023-06-19 13:59:34 +02:00
check-integrity.h
compression.c btrfs: make btrfs_compressed_bioset static 2023-06-19 17:01:44 +02:00
compression.h btrfs: pass an ordered_extent to btrfs_submit_compressed_write 2023-06-19 13:59:36 +02:00
ctree.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
ctree.h btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
defrag.c btrfs: drop gfp from parameter extent state helpers 2023-06-19 13:59:30 +02:00
defrag.h btrfs: move defrag related prototypes to their own header 2022-12-05 18:00:46 +01:00
delalloc-space.c btrfs: fix qgroup_free_reserved_data int overflow 2023-12-20 17:02:03 +01:00
delalloc-space.h btrfs: move delalloc space related prototypes to delalloc-space.h 2022-12-05 18:00:44 +01:00
delayed-inode.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
delayed-inode.h btrfs: add __counted_by for struct btrfs_delayed_item and use struct_size() 2023-10-11 11:37:19 +02:00
delayed-ref.c btrfs: prevent transaction block reserve underflow when starting transaction 2023-09-20 20:42:18 +02:00
delayed-ref.h btrfs: prevent transaction block reserve underflow when starting transaction 2023-09-20 20:42:18 +02:00
dev-replace.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
dev-replace.h btrfs: move dev-replace prototypes into dev-replace.h 2022-12-05 18:00:47 +01:00
dir-item.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
dir-item.h btrfs: move dir-item prototypes into dir-item.h 2022-12-05 18:00:46 +01:00
discard.c btrfs: unexport btrfs_run_discard_work and make it static 2023-06-19 13:59:25 +02:00
discard.h btrfs: unexport btrfs_run_discard_work and make it static 2023-06-19 13:59:25 +02:00
disk-io.c btrfs: free qgroup pertrans reserve on transaction abort 2024-01-01 12:42:24 +00:00
disk-io.h btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
export.c btrfs: move super_block specific helpers into super.h 2022-12-05 18:00:47 +01:00
export.h btrfs: simplify generation check in btrfs_get_dentry 2022-12-05 18:00:41 +01:00
extent_io.c btrfs: don't clear qgroup reserved bit in release_folio 2023-12-20 17:02:03 +01:00
extent_io.h btrfs: zoned: introduce block group context to btrfs_eb_write_context 2023-08-21 14:52:19 +02:00
extent_map.c btrfs: fix incorrect splitting in btrfs_drop_extent_map_range 2023-08-18 14:38:10 +02:00
extent_map.h btrfs: pass the new logical address to split_extent_map 2023-06-19 13:59:33 +02:00
extent-io-tree.c btrfs: make find_first_extent_bit() return a boolean 2023-08-21 14:52:12 +02:00
extent-io-tree.h btrfs: make find_first_extent_bit() return a boolean 2023-08-21 14:52:12 +02:00
extent-tree.c btrfs: zoned: optimize hint byte for zoned allocator 2024-01-31 16:19:10 -08:00
extent-tree.h btrfs: wait on uncached block groups on every allocation loop 2023-08-21 14:54:47 +02:00
file-item.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
file-item.h btrfs: scrub: avoid unnecessary csum tree search preparing stripes 2023-08-21 14:54:48 +02:00
file.c btrfs: fix qgroup_free_reserved_data int overflow 2023-12-20 17:02:03 +01:00
file.h btrfs: use cached state when looking for delalloc ranges with fiemap 2022-12-05 18:00:56 +01:00
free-space-cache.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
free-space-cache.h btrfs: move btrfs_check_trunc_cache_free_space into block-rsv.c 2023-06-19 13:59:24 +02:00
free-space-tree.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
free-space-tree.h btrfs: make clear_cache mount option to rebuild FST without disabling it 2023-05-10 14:51:27 +02:00
fs.c btrfs: sysfs: update fs features directory asynchronously 2023-02-13 17:50:35 +01:00
fs.h btrfs: zoned: activate metadata block group on write time 2023-08-21 14:52:19 +02:00
inode-item.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
inode-item.h btrfs: move split_flags/combine_flags helpers to inode-item.h 2023-06-19 13:59:25 +02:00
inode.c btrfs: avoid copying BTRFS_ROOT_SUBVOL_DEAD flag to snapshot of subvolume being deleted 2024-01-31 16:19:05 -08:00
ioctl.c btrfs: don't abort filesystem when attempting to snapshot deleted subvolume 2024-01-31 16:19:06 -08:00
ioctl.h fs: port ->fileattr_set() to pass mnt_idmap 2023-01-19 09:24:27 +01:00
Kconfig MAINTAINERS: remove links to obsolete btrfs.wiki.kernel.org 2023-09-08 14:21:27 +02:00
locking.c btrfs: add block-group tree to lockdep classes 2023-06-19 13:59:35 +02:00
locking.h btrfs: do not block starts waiting on previous transaction commit 2023-09-08 14:10:49 +02:00
lru_cache.c btrfs: send: cache utimes operations for directories if possible 2023-02-15 19:38:50 +01:00
lru_cache.h btrfs: remove btrfs_lru_cache_is_full() inline function 2023-04-17 18:01:18 +02:00
lzo.c btrfs: disable allocation warnings for compression workspaces 2023-06-19 13:59:34 +02:00
Makefile btrfs: send: genericize the backref cache to allow it to be reused 2023-02-13 17:50:35 +01:00
messages.c btrfs: remove v0 extent handling 2023-08-21 14:54:48 +02:00
messages.h btrfs: remove v0 extent handling 2023-08-21 14:54:48 +02:00
misc.h minmax: add in_range() macro 2023-08-24 16:20:18 -07:00
ordered-data.c btrfs: fix qgroup_free_reserved_data int overflow 2023-12-20 17:02:03 +01:00
ordered-data.h btrfs: add a btrfs_finish_ordered_extent helper 2023-06-19 13:59:37 +02:00
orphan.c btrfs: move orphan prototypes into orphan.h 2022-12-05 18:00:47 +01:00
orphan.h btrfs: move orphan prototypes into orphan.h 2022-12-05 18:00:47 +01:00
print-tree.c btrfs: remove v0 extent handling 2023-08-21 14:54:48 +02:00
print-tree.h btrfs: print-tree: pass const extent buffer pointer 2023-06-19 13:59:22 +02:00
props.c btrfs: move super_block specific helpers into super.h 2022-12-05 18:00:47 +01:00
props.h btrfs: make module init/exit match their sequence 2022-12-05 18:00:40 +01:00
qgroup.c btrfs: free qgroup pertrans reserve on transaction abort 2024-01-01 12:42:24 +00:00
qgroup.h btrfs: qgroup: iterate qgroups without memory allocation for qgroup_reserve() 2024-01-01 12:42:24 +00:00
raid56.c btrfs: scrub: avoid unnecessary csum tree search preparing stripes 2023-08-21 14:54:48 +02:00
raid56.h btrfs: raid56: remove unused BTRFS_RBIO_REBUILD_MISSING 2023-08-21 14:52:12 +02:00
rcu-string.h btrfs: replace strncpy() with strscpy() 2022-12-05 18:00:59 +01:00
ref-verify.c btrfs: ref-verify: free ref cache before clearing mount opt 2024-01-31 16:19:06 -08:00
ref-verify.h
reflink.c btrfs: convert to ctime accessor functions 2023-07-13 10:28:04 +02:00
reflink.h
relocation.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
relocation.h btrfs: pass an ordered_extent to btrfs_reloc_clone_csums 2023-06-19 13:59:36 +02:00
root-tree.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
root-tree.h btrfs: move root tree prototypes to their own header 2022-12-05 18:00:44 +01:00
scrub.c btrfs: scrub: avoid use-after-free when chunk length is not 64K aligned 2024-01-31 16:19:05 -08:00
scrub.h btrfs: scrub: remove scrub_bio structure 2023-04-17 18:01:24 +02:00
send.c btrfs: send: ensure send_fd is writable 2023-12-08 08:52:20 +01:00
send.h btrfs: send add define for v2 buffer size 2022-12-05 18:00:41 +01:00
space-info.c btrfs: zoned: re-enable metadata over-commit for zoned mode 2023-08-21 14:52:19 +02:00
space-info.h btrfs: update documentation for BTRFS_RESERVE_FLUSH_EVICT flush method 2023-04-17 18:01:18 +02:00
subpage.c btrfs: stop setting PageError in the data I/O path 2023-06-19 13:59:35 +02:00
subpage.h btrfs: stop setting PageError in the data I/O path 2023-06-19 13:59:35 +02:00
super.c btrfs: add dmesg output for first mount and last unmount of a filesystem 2023-12-08 08:52:20 +01:00
super.h btrfs: move super_block specific helpers into super.h 2022-12-05 18:00:47 +01:00
sysfs.c btrfs: sysfs: validate scrub_speed_max value 2024-01-31 16:18:49 -08:00
sysfs.h btrfs: sysfs: update fs features directory asynchronously 2023-02-13 17:50:35 +01:00
transaction.c btrfs: free qgroup pertrans reserve on transaction abort 2024-01-01 12:42:24 +00:00
transaction.h btrfs: free qgroup pertrans reserve on transaction abort 2024-01-01 12:42:24 +00:00
tree-checker.c btrfs: tree-checker: fix inline ref size in error messages 2024-01-31 16:19:06 -08:00
tree-checker.h btrfs: move btrfs_verify_level_key into tree-checker.c 2023-06-19 13:59:25 +02:00
tree-log.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
tree-log.h btrfs: change for_rename argument of btrfs_record_unlink_dir() to bool 2023-06-19 13:59:26 +02:00
tree-mod-log.c btrfs: avoid tree mod log ENOMEM failures when we don't need to log 2023-06-19 13:59:38 +02:00
tree-mod-log.h btrfs: fix SPDX comment in tree-mod-log.h 2022-12-05 18:00:48 +01:00
ulist.c btrfs: constify ulist parameter of ulist_next() 2022-12-05 18:00:50 +01:00
ulist.h btrfs: constify ulist parameter of ulist_next() 2022-12-05 18:00:50 +01:00
uuid-tree.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
uuid-tree.h btrfs: move uuid tree prototypes to uuid-tree.h 2022-12-05 18:00:46 +01:00
verity.c btrfs: convert btrfs_read_merkle_tree_page() to use a folio 2023-09-13 18:40:54 +02:00
verity.h btrfs: move verity prototypes into verity.h 2022-12-05 18:00:47 +01:00
volumes.c btrfs: make error messages more clear when getting a chunk map 2023-12-08 08:52:20 +01:00
volumes.h btrfs: add a helper to read the superblock metadata_uuid 2023-08-21 14:54:48 +02:00
xattr.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-11-28 17:19:35 +00:00
xattr.h
zlib.c btrfs: disable allocation warnings for compression workspaces 2023-06-19 13:59:34 +02:00
zoned.c btrfs: zoned: fix lock ordering in btrfs_zone_activate() 2024-01-31 16:19:05 -08:00
zoned.h btrfs: zoned: reserve zones for an active metadata/system block group 2023-08-21 14:52:19 +02:00
zstd.c btrfs: disable allocation warnings for compression workspaces 2023-06-19 13:59:34 +02:00