From: Deepanshu Kartikey Date: Thu, 9 Oct 2025 15:49:03 +0000 (+0530) Subject: ocfs2: clear extent cache after moving/defragmenting extents X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=78a63493f8e352296dbc7cb7b3f4973105e8679e;p=users%2Fhch%2Fmisc.git ocfs2: clear extent cache after moving/defragmenting extents The extent map cache can become stale when extents are moved or defragmented, causing subsequent operations to see outdated extent flags. This triggers a BUG_ON in ocfs2_refcount_cal_cow_clusters(). The problem occurs when: 1. copy_file_range() creates a reflinked extent with OCFS2_EXT_REFCOUNTED 2. ioctl(FITRIM) triggers ocfs2_move_extents() 3. __ocfs2_move_extents_range() reads and caches the extent (flags=0x2) 4. ocfs2_move_extent()/ocfs2_defrag_extent() calls __ocfs2_move_extent() which clears OCFS2_EXT_REFCOUNTED flag on disk (flags=0x0) 5. The extent map cache is not invalidated after the move 6. Later write() operations read stale cached flags (0x2) but disk has updated flags (0x0), causing a mismatch 7. BUG_ON(!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) triggers Fix by clearing the extent map cache after each extent move/defrag operation in __ocfs2_move_extents_range(). This ensures subsequent operations read fresh extent data from disk. Link: https://lore.kernel.org/all/20251009142917.517229-1-kartikey406@gmail.com/T/ Link: https://lkml.kernel.org/r/20251009154903.522339-1-kartikey406@gmail.com Fixes: 53069d4e7695 ("Ocfs2/move_extents: move/defrag extents within a certain range.") Signed-off-by: Deepanshu Kartikey Reported-by: syzbot+6fdd8fa3380730a4b22c@syzkaller.appspotmail.com Tested-by: syzbot+6fdd8fa3380730a4b22c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?id=2959889e1f6e216585ce522f7e8bc002b46ad9e7 Reviewed-by: Mark Fasheh Reviewed-by: Joseph Qi Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Signed-off-by: Andrew Morton --- diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c index 86f2631e6360..10923bf7c8b8 100644 --- a/fs/ocfs2/move_extents.c +++ b/fs/ocfs2/move_extents.c @@ -867,6 +867,11 @@ static int __ocfs2_move_extents_range(struct buffer_head *di_bh, mlog_errno(ret); goto out; } + /* + * Invalidate extent cache after moving/defragging to prevent + * stale cached data with outdated extent flags. + */ + ocfs2_extent_map_trunc(inode, cpos); context->clusters_moved += alloc_size; next: