Currently we clear BH_New bit in case of error and also in the standard
ext4_write_end() handler (in block_commit_write()). However
ext4_journalled_write_end() misses this clearing and thus we are leaving
stale BH_New bits behind. Generally ext4_block_write_begin() clears
these bits before any harm can be done but in case blocksize < pagesize
and we hit some error when processing a page with these stale bits,
we'll try to zero buffers with these stale BH_New bits and jbd2 will
complain (as buffers were not prepared for writing in this transaction).
Fix the problem by clearing BH_New bits in ext4_journalled_write_end()
and WARN if ext4_block_write_begin() sees stale BH_New bits.
Reported-and-tested-by: Baolin Liu <liubaolin@xxxxxxxxxx>
Reported-and-tested-by: Zhi Long <longzhi@xxxxxxxxxxxxxx>
Fixes: 3910b513fcdf ("ext4: persist the new uptodate buffers in ext4_journalled_zero_new_buffers")
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/ext4/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
- changes since v1: Updated tags
- changes since v2: Fixup email address in tags
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 54bdd4884fe6..aa56af4a92ad 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1049,7 +1049,7 @@ int ext4_block_write_begin(handle_t *handle, struct folio *folio,
}
continue;
}
- if (buffer_new(bh))
+ if (WARN_ON_ONCE(buffer_new(bh)))
clear_buffer_new(bh);
if (!buffer_mapped(bh)) {
WARN_ON(bh->b_size != blocksize);
@@ -1265,6 +1265,7 @@ static int write_end_fn(handle_t *handle, struct inode *inode,
ret = ext4_dirty_journalled_data(handle, bh);
clear_buffer_meta(bh);
clear_buffer_prio(bh);
+ clear_buffer_new(bh);
return ret;
}
--
2.35.3
