linux/fs/btrfs
Nikolay Borisov 5750c37523 btrfs: Correctly handle empty trees in find_first_clear_extent_bit
Raviu reported that running his regular fs_trim segfaulted with the
following backtrace:

[  237.525947] assertion failed: prev, in ../fs/btrfs/extent_io.c:1595
[  237.525984] ------------[ cut here ]------------
[  237.525985] kernel BUG at ../fs/btrfs/ctree.h:3117!
[  237.525992] invalid opcode: 0000 [#1] SMP PTI
[  237.525998] CPU: 4 PID: 4423 Comm: fstrim Tainted: G     U     OE     5.4.14-8-vanilla #1
[  237.526001] Hardware name: ASUSTeK COMPUTER INC.
[  237.526044] RIP: 0010:assfail.constprop.58+0x18/0x1a [btrfs]
[  237.526079] Call Trace:
[  237.526120]  find_first_clear_extent_bit+0x13d/0x150 [btrfs]
[  237.526148]  btrfs_trim_fs+0x211/0x3f0 [btrfs]
[  237.526184]  btrfs_ioctl_fitrim+0x103/0x170 [btrfs]
[  237.526219]  btrfs_ioctl+0x129a/0x2ed0 [btrfs]
[  237.526227]  ? filemap_map_pages+0x190/0x3d0
[  237.526232]  ? do_filp_open+0xaf/0x110
[  237.526238]  ? _copy_to_user+0x22/0x30
[  237.526242]  ? cp_new_stat+0x150/0x180
[  237.526247]  ? do_vfs_ioctl+0xa4/0x640
[  237.526278]  ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[  237.526283]  do_vfs_ioctl+0xa4/0x640
[  237.526288]  ? __do_sys_newfstat+0x3c/0x60
[  237.526292]  ksys_ioctl+0x70/0x80
[  237.526297]  __x64_sys_ioctl+0x16/0x20
[  237.526303]  do_syscall_64+0x5a/0x1c0
[  237.526310]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

That was due to btrfs_fs_device::aloc_tree being empty. Initially I
thought this wasn't possible and as a percaution have put the assert in
find_first_clear_extent_bit. Turns out this is indeed possible and could
happen when a file system with SINGLE data/metadata profile has a 2nd
device added. Until balance is run or a new chunk is allocated on this
device it will be completely empty.

In this case find_first_clear_extent_bit should return the full range
[0, -1ULL] and let the caller handle this i.e for trim the end will be
capped at the size of actual device.

Link: https://lore.kernel.org/linux-btrfs/izW2WNyvy1dEDweBICizKnd2KDwDiDyY2EYQr4YCwk7pkuIpthx-JRn65MPBde00ND6V0_Lh8mW0kZwzDiLDv25pUYWxkskWNJnVP0kgdMA=@protonmail.com/
Fixes: 45bfcfc168 ("btrfs: Implement find_first_clear_extent_bit")
CC: stable@vger.kernel.org # 5.2+
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-31 14:01:29 +01:00
..
tests btrfs: Correctly handle empty trees in find_first_clear_extent_bit 2020-01-31 14:01:29 +01:00
acl.c btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
async-thread.c btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
async-thread.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
backref.c Btrfs: fix deadlock between fiemap and transaction commits 2019-07-30 18:25:12 +02:00
backref.h btrfs: fiemap: preallocate ulists for btrfs_check_shared 2019-07-01 13:34:53 +02:00
block-group.c btrfs: Refactor btrfs_rmap_block to improve readability 2020-01-23 17:24:35 +01:00
block-group.h btrfs: Move and unexport btrfs_rmap_block 2020-01-23 17:24:34 +01:00
block-rsv.c btrfs: use btrfs_try_granting_tickets in update_global_rsv 2019-09-09 14:59:19 +02:00
block-rsv.h btrfs: migrate the global_block_rsv helpers to block-rsv.c 2019-07-02 12:30:55 +02:00
btrfs_inode.h Btrfs: remove unnecessary delalloc mutex for inodes 2019-11-18 17:51:46 +01:00
check-integrity.c btrfs: remove superfluous BUG_ON() in integrity checks 2020-01-20 16:40:52 +01:00
check-integrity.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
compression.c btrfs: get rid of at_offset parameter to btrfs_lookup_bio_sums() 2020-01-20 16:40:54 +01:00
compression.h btrfs: compression: remove ops pointer from workspace_manager 2019-11-18 12:46:59 +01:00
ctree.c Btrfs: fix race between adding and putting tree mod seq elements and nodes 2020-01-31 14:01:20 +01:00
ctree.h Btrfs: fix race between adding and putting tree mod seq elements and nodes 2020-01-31 14:01:20 +01:00
delalloc-space.c Btrfs: remove unnecessary delalloc mutex for inodes 2019-11-18 17:51:46 +01:00
delalloc-space.h btrfs: migrate the delalloc space stuff to it's own home 2019-07-04 17:26:17 +02:00
delayed-inode.c btrfs: use refcount_inc_not_zero in kill_all_nodes 2019-11-18 12:46:51 +01:00
delayed-inode.h Btrfs: delayed-inode: use rb_first_cached for ins_root and del_root 2018-10-15 17:23:33 +02:00
delayed-ref.c Btrfs: fix race between adding and putting tree mod seq elements and nodes 2020-01-31 14:01:20 +01:00
delayed-ref.h btrfs: migrate the delayed refs rsv code 2019-07-04 17:26:17 +02:00
dev-replace.c btrfs: sysfs, add devid/dev_state kobject and device attributes 2020-01-23 17:24:36 +01:00
dev-replace.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
dir-item.c btrfs: remove unused parameter fs_info from btrfs_extend_item 2019-04-29 19:02:50 +02:00
discard.c btrfs: add correction to handle -1 edge case in async discard 2020-01-20 16:41:01 +01:00
discard.h btrfs: have multiple discard lists 2020-01-20 16:41:00 +01:00
disk-io.c Btrfs: fix race between adding and putting tree mod seq elements and nodes 2020-01-31 14:01:20 +01:00
disk-io.h btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
export.c btrfs: drop unused parameter is_new from btrfs_iget 2019-11-18 12:46:52 +01:00
export.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
extent_io.c btrfs: Correctly handle empty trees in find_first_clear_extent_bit 2020-01-31 14:01:29 +01:00
extent_io.h btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
extent_map.c btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
extent_map.h btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
extent-io-tree.h btrfs: move the failrec tree stuff into extent-io-tree.h 2019-11-18 12:46:47 +01:00
extent-tree.c btrfs: calculate discard delay based on number of extents 2020-01-20 16:40:59 +01:00
file-item.c btrfs: safely advance counter when looking up bio csums 2020-01-20 16:41:01 +01:00
file.c btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
free-space-cache.c btrfs: ensure removal of discardable_* in free_bitmap() 2020-01-20 16:41:01 +01:00
free-space-cache.h btrfs: have multiple discard lists 2020-01-20 16:41:00 +01:00
free-space-tree.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
free-space-tree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
inode-item.c btrfs: Make btrfs_find_name_in_ext_backref return struct btrfs_inode_extref 2019-09-09 14:59:16 +02:00
inode-map.c btrfs: keep track of which extents have been discarded 2020-01-20 16:40:57 +01:00
inode-map.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
inode.c btrfs: rename DISCARD mount option to to DISCARD_SYNC 2020-01-20 16:40:57 +01:00
ioctl.c btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
Kconfig btrfs: add Kconfig dependency for BLAKE2B 2019-12-09 17:56:06 +01:00
locking.c btrfs: document extent buffer locking 2019-11-18 17:51:50 +01:00
locking.h btrfs: move btrfs_unlock_up_safe to other locking functions 2019-11-18 12:46:49 +01:00
lzo.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
Makefile btrfs: add the beginning of async discard, discard workqueue 2020-01-20 16:40:57 +01:00
misc.h btrfs: add 64bit safe helper for power of two checks 2019-11-18 12:46:50 +01:00
ordered-data.c btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_item 2020-01-20 16:40:54 +01:00
ordered-data.h btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_item 2020-01-20 16:40:54 +01:00
orphan.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
print-tree.c btrfs: Remove unneeded semicolon 2020-01-20 16:40:55 +01:00
print-tree.h btrfs: print-tree: debugging output enhancement 2018-04-20 19:18:16 +02:00
props.c btrfs: props: remove unnecessary hash_init() 2019-11-18 12:46:55 +01:00
props.h btrfs: delete unused function btrfs_set_prop_trans 2019-04-29 19:02:54 +02:00
qgroup.c btrfs: qgroup: return ENOTCONN instead of EINVAL when quotas are not enabled 2020-01-20 16:40:50 +01:00
qgroup.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
raid56.c btrfs: remove pointless local variable in lock_stripe_add() 2019-11-18 12:47:00 +01:00
raid56.h btrfs: constify map parameter for nr_parity_stripes and nr_data_stripes 2019-07-01 13:34:58 +02:00
rcu-string.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
reada.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
ref-verify.c btrfs: fix uninitialized ret in ref-verify 2019-10-03 15:00:56 +02:00
ref-verify.h btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod() 2019-04-29 19:02:49 +02:00
relocation.c btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_item 2020-01-20 16:40:54 +01:00
root-tree.c btrfs: do not delete mismatched root refs 2020-01-08 14:44:24 +01:00
scrub.c btrfs: handle empty block_group removal for async discard 2020-01-20 16:40:57 +01:00
send.c btrfs: send: remove WARN_ON for readonly mount 2019-12-13 14:10:46 +01:00
send.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
space-info.c btrfs: don't pass system_chunk into can_overcommit 2020-01-20 16:40:52 +01:00
space-info.h Btrfs: remove wait queue from space_info structure 2019-11-18 17:51:46 +01:00
struct-funcs.c btrfs: tie extent buffer and it's token together 2019-09-09 14:59:16 +02:00
super.c btrfs: add the beginning of async discard, discard workqueue 2020-01-20 16:40:57 +01:00
sysfs.c btrfs: sysfs, add devid/dev_state kobject and device attributes 2020-01-23 17:24:36 +01:00
sysfs.h btrfs: sysfs, add devid/dev_state kobject and device attributes 2020-01-23 17:24:36 +01:00
transaction.c btrfs: set trans->drity in btrfs_commit_transaction 2020-01-23 17:24:37 +01:00
transaction.h btrfs: Rename btrfs_join_transaction_nolock 2019-11-18 12:46:54 +01:00
tree-checker.c btrfs: tree-checker: Verify location key for DIR_ITEM/DIR_INDEX 2020-01-20 16:40:56 +01:00
tree-checker.h btrfs: get fs_info from eb in btrfs_check_chunk_valid 2019-04-29 19:02:39 +02:00
tree-defrag.c btrfs: open code now trivial btrfs_set_lock_blocking 2019-02-25 14:13:27 +01:00
tree-log.c Btrfs: fix infinite loop during fsync after rename operations 2020-01-23 17:24:37 +01:00
tree-log.h btrfs: get fs_info from trans in btrfs_set_log_full_commit 2019-04-29 19:02:41 +02:00
ulist.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
ulist.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
uuid-tree.c btrfs: handle ENOENT in btrfs_uuid_tree_iterate 2019-12-13 14:10:45 +01:00
volumes.c btrfs: Fix split-brain handling when changing FSID to metadata uuid 2020-01-23 17:24:39 +01:00
volumes.h btrfs: sysfs, add devid/dev_state kobject and device attributes 2020-01-23 17:24:36 +01:00
xattr.c Btrfs: fix failure to persist compression property xattr deletion on fsync 2019-06-17 16:37:17 +02:00
xattr.h btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
zlib.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
zstd.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00