diff options
| author | Julian Sun <sunjunchao@bytedance.com> | 2025-12-08 20:37:13 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2026-01-18 11:23:10 -0500 |
| commit | 0ef7ef422730b8585214a2825735838d664ce1be (patch) | |
| tree | e0b2dbe479d52bc8b7e6bc43e6c28d9b841de14e /fs | |
| parent | cd16edba1c6a24af138e1a5ded2711231fffa99f (diff) | |
ext4: add missing down_write_data_sem in mext_move_extent().
Commit 962e8a01eab9 ("ext4: introduce mext_move_extent()") attempts to
call ext4_swap_extents() on the failure path to recover the swapped
extents, but fails to acquire locks for the two inode->i_data_sem,
triggering the BUG_ON statement in ext4_swap_extents().
This issue can be fixed by calling ext4_double_down_write_data_sem()
before ext4_swap_extents().
Signed-off-by: Julian Sun <sunjunchao@bytedance.com>
Reported-by: syzbot+4ea6bd8737669b423aae@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/69368649.a70a0220.38f243.0093.GAE@google.com/
Fixes: 962e8a01eab9 ("ext4: introduce mext_move_extent()")
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://patch.msgid.link/20251208123713.1971068-1-sunjunchao@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/move_extent.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 0550fd30fd10..635fb8a52e0c 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -393,9 +393,11 @@ out: repair_branches: ret2 = 0; + ext4_double_down_write_data_sem(orig_inode, donor_inode); r_len = ext4_swap_extents(handle, donor_inode, orig_inode, mext->donor_lblk, orig_map->m_lblk, *m_len, 0, &ret2); + ext4_double_up_write_data_sem(orig_inode, donor_inode); if (ret2 || r_len != *m_len) { ext4_error_inode_block(orig_inode, (sector_t)(orig_map->m_lblk), EIO, "Unable to copy data block, data will be lost!"); |