On Mon 17-02-25 14:59:55, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
>
> In __jbd2_journal_erase(), the block_stop parameter includes the last
> block of a contiguous region; however, the calculation of byte_stop is
> incorrect, as it does not account for the bytes in that last block.
> Consequently, the page cache is not cleared properly, which occasionally
> causes the ext4/050 test to fail.
>
> Since block_stop operates on inclusion semantics, it involves repeated
> increments and decrements by 1, significantly increasing the complexity
> of the calculations. Optimize the calculation and fix the incorrect
> byte_stop by make both block_stop and byte_stop to use exclusion
> semantics.
>
> This fixes a failure in fstests ext4/050.
>
> Fixes: 01d5d96542fd ("ext4: add discard/zeroout flags to journal flush")
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
Looks good! Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/jbd2/journal.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index d8084b31b361..49a9e99cbc03 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -1965,17 +1965,15 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
> return err;
> }
>
> - if (block_start == ~0ULL) {
> - block_start = phys_block;
> - block_stop = block_start - 1;
> - }
> + if (block_start == ~0ULL)
> + block_stop = block_start = phys_block;
>
> /*
> * last block not contiguous with current block,
> * process last contiguous region and return to this block on
> * next loop
> */
> - if (phys_block != block_stop + 1) {
> + if (phys_block != block_stop) {
> block--;
> } else {
> block_stop++;
> @@ -1994,11 +1992,10 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
> */
> byte_start = block_start * journal->j_blocksize;
> byte_stop = block_stop * journal->j_blocksize;
> - byte_count = (block_stop - block_start + 1) *
> - journal->j_blocksize;
> + byte_count = (block_stop - block_start) * journal->j_blocksize;
>
> truncate_inode_pages_range(journal->j_dev->bd_mapping,
> - byte_start, byte_stop);
> + byte_start, byte_stop - 1);
>
> if (flags & JBD2_JOURNAL_FLUSH_DISCARD) {
> err = blkdev_issue_discard(journal->j_dev,
> @@ -2013,7 +2010,7 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
> }
>
> if (unlikely(err != 0)) {
> - pr_err("JBD2: (error %d) unable to wipe journal at physical blocks %llu - %llu",
> + pr_err("JBD2: (error %d) unable to wipe journal at physical blocks [%llu, %llu)",
> err, block_start, block_stop);
> return err;
> }
> --
> 2.46.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
