kernel/git/stable/linux.git/fs/btrfs, branch linux-5.19.y

btrfs: call __btrfs_remove_free_space_cache_locked on cache load failure

2022-10-24T07:58:22+00:00

[ Upstream commit 8a1ae2781dee9fc21ca82db682d37bea4bd074ad ] Now that lockdep is staying enabled through our entire CI runs I started seeing the following stack in generic/475 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2171864 at fs/btrfs/discard.c:604 btrfs_discard_update_discardable+0x98/0xb0 CPU: 1 PID: 2171864 Comm: kworker/u4:0 Not tainted 5.19.0-rc8+ #789 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Workqueue: btrfs-cache btrfs_work_helper RIP: 0010:btrfs_discard_update_discardable+0x98/0xb0 RSP: 0018:ffffb857c2f7bad0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8c85c605c200 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff86807c5b RDI: ffffffff868a831e RBP: ffff8c85c4c54000 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8c85c66932f0 R11: 0000000000000001 R12: ffff8c85c3899010 R13: ffff8c85d5be4f40 R14: ffff8c85c4c54000 R15: ffff8c86114bfa80 FS: 0000000000000000(0000) GS:ffff8c863bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2e7f168160 CR3: 000000010289a004 CR4: 0000000000370ee0 Call Trace: __btrfs_remove_free_space_cache+0x27/0x30 load_free_space_cache+0xad2/0xaf0 caching_thread+0x40b/0x650 ? lock_release+0x137/0x2d0 btrfs_work_helper+0xf2/0x3e0 ? lock_is_held_type+0xe2/0x140 process_one_work+0x271/0x590 ? process_one_work+0x590/0x590 worker_thread+0x52/0x3b0 ? process_one_work+0x590/0x590 kthread+0xf0/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 This is the code ctl = block_group->free_space_ctl; discard_ctl = &block_group->fs_info->discard_ctl; lockdep_assert_held(&ctl->tree_lock); We have a temporary free space ctl for loading the free space cache in order to avoid having allocations happening while we're loading the cache. When we hit an error we free it all up, however this also calls btrfs_discard_update_discardable, which requires block_group->free_space_ctl->tree_lock to be held. However this is our temporary ctl so this lock isn't held. Fix this by calling __btrfs_remove_free_space_cache_locked instead so that we only clean up the entries and do not mess with the discardable stats. Signed-off-by: Josef Bacik Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: don't print information about space cache or tree every remount

2022-10-24T07:58:22+00:00

[ Upstream commit dbecac26630014d336a8e5ea67096ff18210fb9c ] btrfs currently prints information about space cache or free space tree being in use on every remount, regardless whether such remount actually enabled or disabled one of these features. This is actually unnecessary since providing remount options changing the state of these features will explicitly print the appropriate notice. Let's instead print such unconditional information just on an initial mount to avoid filling the kernel log when, for example, laptop-mode-tools remount the fs on some events. Signed-off-by: Maciej S. Szmigiero Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: scrub: try to fix super block errors

2022-10-24T07:58:22+00:00

[ Upstream commit f9eab5f0bba76742af654f33d517bf62a0db8f12 ] [BUG] The following script shows that, although scrub can detect super block errors, it never tries to fix it: mkfs.btrfs -f -d raid1 -m raid1 $dev1 $dev2 xfs_io -c "pwrite 67108864 4k" $dev2 mount $dev1 $mnt btrfs scrub start -B $dev2 btrfs scrub start -Br $dev2 umount $mnt The first scrub reports the super error correctly: scrub done for f3289218-abd3-41ac-a630-202f766c0859 Scrub started: Tue Aug 2 14:44:11 2022 Status: finished Duration: 0:00:00 Total to scrub: 1.26GiB Rate: 0.00B/s Error summary: super=1 Corrected: 0 Uncorrectable: 0 Unverified: 0 But the second read-only scrub still reports the same super error: Scrub started: Tue Aug 2 14:44:11 2022 Status: finished Duration: 0:00:00 Total to scrub: 1.26GiB Rate: 0.00B/s Error summary: super=1 Corrected: 0 Uncorrectable: 0 Unverified: 0 [CAUSE] The comments already shows that super block can be easily fixed by committing a transaction: /* * If we find an error in a super block, we just report it. * They will get written with the next transaction commit * anyway */ But the truth is, such assumption is not always true, and since scrub should try to repair every error it found (except for read-only scrub), we should really actively commit a transaction to fix this. [FIX] Just commit a transaction if we found any super block errors, after everything else is done. We cannot do this just after scrub_supers(), as btrfs_commit_transaction() will try to pause and wait for the running scrub, thus we can not call it with scrub_lock hold. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: scrub: properly report super block errors in system log

2022-10-24T07:58:22+00:00

[ Upstream commit e69bf81c9a339f1b2c041b112a6fbb9f60fc9340 ] [PROBLEM] Unlike data/metadata corruption, if scrub detected some error in the super block, the only error message is from the updated device status: BTRFS info (device dm-1): scrub: started on devid 2 BTRFS error (device dm-1): bdev /dev/mapper/test-scratch2 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0 BTRFS info (device dm-1): scrub: finished on devid 2 with status: 0 This is not helpful at all. [CAUSE] Unlike data/metadata error reporting, there is no visible report in kernel dmesg to report supper block errors. In fact, return value of scrub_checksum_super() is intentionally skipped, thus scrub_handle_errored_block() will never be called for super blocks. [FIX] Make super block errors to output an error message, now the full dmesg would looks like this: BTRFS info (device dm-1): scrub: started on devid 2 BTRFS warning (device dm-1): super block error on device /dev/mapper/test-scratch2, physical 67108864 BTRFS error (device dm-1): bdev /dev/mapper/test-scratch2 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0 BTRFS info (device dm-1): scrub: finished on devid 2 with status: 0 BTRFS info (device dm-1): scrub: started on devid 2 This fix involves: - Move the super_errors reporting to scrub_handle_errored_block() This allows the device status message to show after the super block error message. But now we no longer distinguish super block corruption and generation mismatch, now all counted as corruption. - Properly check the return value from scrub_checksum_super() - Add extra super block error reporting for scrub_print_warning(). Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: dump extra info if one free space cache has more bitmaps than it should

2022-10-24T07:58:22+00:00

[ Upstream commit 62cd9d4474282a1eb84f945955c56cbfc42e1ffe ] There is an internal report on hitting the following ASSERT() in recalculate_thresholds(): ASSERT(ctl->total_bitmaps <= max_bitmaps); Above @max_bitmaps is calculated using the following variables: - bytes_per_bg 8 * 4096 * 4096 (128M) for x86_64/x86. - block_group->length The length of the block group. @max_bitmaps is the rounded up value of block_group->length / 128M. Normally one free space cache should not have more bitmaps than above value, but when it happens the ASSERT() can be triggered if CONFIG_BTRFS_ASSERT is also enabled. But the ASSERT() itself won't provide enough info to know which is going wrong. Is the bg too small thus it only allows one bitmap? Or is there something else wrong? So although I haven't found extra reports or crash dump to do further investigation, add the extra info to make it more helpful to debug. Reviewed-by: Anand Jain Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: set generation before calling btrfs_clean_tree_block in btrfs_init_new_buffer

2022-10-24T07:56:53+00:00

commit cbddcc4fa3443fe8cfb2ff8e210deb1f6a0eea38 upstream. syzbot is reporting uninit-value in btrfs_clean_tree_block() [1], for commit bc877d285ca3dba2 ("btrfs: Deduplicate extent_buffer init code") missed that btrfs_set_header_generation() in btrfs_init_new_buffer() must not be moved to after clean_tree_block() because clean_tree_block() is calling btrfs_header_generation() since commit 55c69072d6bd5be1 ("Btrfs: Fix extent_buffer usage when nodesize != leafsize"). Since memzero_extent_buffer() will reset "struct btrfs_header" part, we can't move btrfs_set_header_generation() to before memzero_extent_buffer(). Just re-add btrfs_set_header_generation() before btrfs_clean_tree_block(). Link: https://syzkaller.appspot.com/bug?extid=fba8e2116a12609b6c59 [1] Reported-by: syzbot Fixes: bc877d285ca3dba2 ("btrfs: Deduplicate extent_buffer init code") CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Tetsuo Handa Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: fix missed extent on fsync after dropping extent maps

2022-10-24T07:56:52+00:00

commit cef7820d6abf8d61f8e1db411eae3c712f6d72a2 upstream. When dropping extent maps for a range, through btrfs_drop_extent_cache(), if we find an extent map that starts before our target range and/or ends before the target range, and we are not able to allocate extent maps for splitting that extent map, then we don't fail and simply remove the entire extent map from the inode's extent map tree. This is generally fine, because in case anyone needs to access the extent map, it can just load it again later from the respective file extent item(s) in the subvolume btree. However, if that extent map is new and is in the list of modified extents, then a fast fsync will miss the parts of the extent that were outside our range (that needed to be split), therefore not logging them. Fix that by marking the inode for a full fsync. This issue was introduced after removing BUG_ON()s triggered when the split extent map allocations failed, done by commit 7014cdb49305ed ("Btrfs: btrfs_drop_extent_cache should never fail"), back in 2012, and the fast fsync path already existed but was very recent. Also, in the case where we could allocate extent maps for the split operations but then fail to add a split extent map to the tree, mark the inode for a full fsync as well. This is not supposed to ever fail, and we assert that, but in case assertions are disabled (CONFIG_BTRFS_ASSERT is not set), it's the correct thing to do to make sure a fast fsync will not miss a new extent. CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Anand Jain Signed-off-by: Filipe Manana Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: fix race between quota enable and quota rescan ioctl

2022-10-24T07:56:52+00:00

commit 331cd9461412e103d07595a10289de90004ac890 upstream. When enabling quotas, at btrfs_quota_enable(), after committing the transaction, we change fs_info->quota_root to point to the quota root we created and set BTRFS_FS_QUOTA_ENABLED at fs_info->flags. Then we try to start the qgroup rescan worker, first by initializing it with a call to qgroup_rescan_init() - however if that fails we end up freeing the quota root but we leave fs_info->quota_root still pointing to it, this can later result in a use-after-free somewhere else. We have previously set the flags BTRFS_FS_QUOTA_ENABLED and BTRFS_QGROUP_STATUS_FLAG_ON, so we can only fail with -EINPROGRESS at btrfs_quota_enable(), which is possible if someone already called the quota rescan ioctl, and therefore started the rescan worker. So fix this by ignoring an -EINPROGRESS and asserting we can't get any other error. Reported-by: Ye Bin Link: https://lore.kernel.org/linux-btrfs/20220823015931.421355-1-yebin10@huawei.com/ CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Qu Wenruo Signed-off-by: Filipe Manana Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: enhance unsupported compat RO flags handling

2022-10-24T07:56:52+00:00

commit 81d5d61454c365718655cfc87d8200c84e25d596 upstream. Currently there are two corner cases not handling compat RO flags correctly: - Remount We can still mount the fs RO with compat RO flags, then remount it RW. We should not allow any write into a fs with unsupported RO flags. - Still try to search block group items In fact, behavior/on-disk format change to extent tree should not need a full incompat flag. And since we can ensure fs with unsupported RO flags never got any writes (with above case fixed), then we can even skip block group items search at mount time. This patch will enhance the unsupported RO compat flags by: - Reject read-write remount if there are unsupported RO compat flags - Go dummy block group items directly for unsupported RO compat flags In fact, only changes to chunk/subvolume/root/csum trees should go incompat flags. The latter part should allow future change to extent tree to be compat RO flags. Thus this patch also needs to be backported to all stable trees. CC: stable@vger.kernel.org # 4.9+ Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: fix alignment of VMA for memory mapped files on THP

2022-10-24T07:56:52+00:00

commit b0c582233a8563f3c4228df838cdc67a8807ec78 upstream. With CONFIG_READ_ONLY_THP_FOR_FS, the Linux kernel supports using THPs for read-only mmapped files, such as shared libraries. However, the kernel makes no attempt to actually align those mappings on 2MB boundaries, which makes it impossible to use those THPs most of the time. This issue applies to general file mapping THP as well as existing setups using CONFIG_READ_ONLY_THP_FOR_FS. This is easily fixed by using thp_get_unmapped_area for the unmapped_area function in btrfs, which is what ext2, ext4, fuse, and xfs all use. Initially btrfs had been left out in commit 8c07fc452ac0 ("btrfs: fix alignment of VMA for memory mapped files on THP") as btrfs does not support DAX. However, commit 1854bc6e2420 ("mm/readahead: Align file mappings for non-DAX") removed the DAX requirement. We should now be able to call thp_get_unmapped_area() for btrfs. The problem can be seen in /proc/PID/smaps where THPeligible is set to 0 on mappings to eligible shared object files as shown below. Before this patch: 7fc6a7e18000-7fc6a80cc000 r-xp 00000000 00:1e 199856 /usr/lib64/libcrypto.so.1.1.1k Size: 2768 kB THPeligible: 0 VmFlags: rd ex mr mw me With this patch the library is mapped at a 2MB aligned address: fbdfe200000-7fbdfe4b4000 r-xp 00000000 00:1e 199856 /usr/lib64/libcrypto.so.1.1.1k Size: 2768 kB THPeligible: 1 VmFlags: rd ex mr mw me This fixes the alignment of VMAs for any mmap of a file that has the rd and ex permissions and size >= 2MB. The VMA alignment and THPeligible field for anonymous memory is handled separately and is thus not effected by this change. CC: stable@vger.kernel.org # 5.18+ Signed-off-by: Alexander Zhu Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman