| Message ID | cover.1691054362.git.wqu@suse.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | btrfs: fix an ASSERT() triggered inside prepare_to_merge() | expand |
On Thu, Aug 03, 2023 at 05:20:40PM +0800, Qu Wenruo wrote: > [CHANGELOG] > v4: > - Remove the remaining commas inside the root key prompt of the 2nd > patch Patches added to misc-next, with the WARN_ONs for now but I'd really like to get them removed once we discuss it.
[CHANGELOG] v4: - Remove the remaining commas inside the root key prompt of the 2nd patch v3: - Update the comments and commit messages - Replace the deleted ASSERT(0)s with WARN_ON()s - Remove a debug dump_stack() in the last patch v2: - Add two new patches One to properly fix the root cause (race between quota tree creation and relocation). One to reject obviously corrupted reloc trees. - Remove two ASSERT()s from merge_reloc_roots() [BUG] Syzbot reported an ASSERT() triggered inside prepare_to_merge(), which turns out to be a regression caused by commit 85724171b302 ("btrfs: fix the btrfs_get_global_root return value"). [CAUSE] The race can happen between quota tree creation and relocation, the root cause is btrfs_get_fs_root() can try to read quota tree as one fs tree, thus setting ROOT_SHAREABLE flag. This leads to relocation code to create a new reloc tree for quota tree, which should not happen. Furthermore at later relocation stages, we will grab quota root from fs_info->quota_root, which is not the same as the one read by btrfs_get_fs_root(), thus quota_root->reloc_root is NULL. This triggers the ASSERT() and crash the system. [FIX] - Make sure non-subvolume trees are always grabbed from fs_info This changes btrfs_get_root_ref() to a more explicit checks, and would return PTR_ERR(-ENOENT) if a non-subvolume (data reloc tree still counts as a subvolume tree) objectid is provided. This is the root fix. - Replace the ASSERT() with a more graceful exit Still does the extra kernel warning through btrfs_abort_transaction(), but with more useful error messages. - Reject obviously incorrect reloc trees through tree-checker Just another layer of sanity checks for on-disk data. Qu Wenruo (3): btrfs: avoid race with qgroup tree creation and relocation btrfs: exit gracefully if reloc roots don't match btrfs: reject invalid reloc tree root keys with stack dump fs/btrfs/disk-io.c | 13 +++++++++++- fs/btrfs/relocation.c | 44 +++++++++++++++++++++++++++++++++-------- fs/btrfs/tree-checker.c | 14 +++++++++++++ 3 files changed, 62 insertions(+), 9 deletions(-)