Re: [Ocfs2-devel] [PATCH v2 08/14] ocfs2: replace ll_rw_block()

Joseph Qi
2022-09-06T01:06:32Z

On 9/1/22 9:34 PM, Zhang Yi via Ocfs2-devel wrote:
> ll_rw_block() is not safe for the sync read path because it cannot
> guarantee that submitting read IO if the buffer has been locked. We
> could get false positive EIO after wait_on_buffer() if the buffer has
> been locked by others. So stop using ll_rw_block() in ocfs2.
>
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Looks good to me.
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>

> ---
> fs/ocfs2/aops.c | 2 +-
> fs/ocfs2/super.c | 4 +---
> 2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index af4157f61927..1d65f6ef00ca 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -636,7 +636,7 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
> !buffer_new(bh) &&
> ocfs2_should_read_blk(inode, page, block_start) &&
> (block_start < from || block_end > to)) {
> - ll_rw_block(REQ_OP_READ, 1, &bh);
> + bh_read_nowait(bh, 0);
> *wait_bh++=bh;
> }
>
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> index e2cc9eec287c..26b4c2bfee49 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -1764,9 +1764,7 @@ static int ocfs2_get_sector(struct super_block *sb,
> if (!buffer_dirty(*bh))
> clear_buffer_uptodate(*bh);
> unlock_buffer(*bh);
> - ll_rw_block(REQ_OP_READ, 1, bh);
> - wait_on_buffer(*bh);
> - if (!buffer_uptodate(*bh)) {
> + if (bh_read(*bh, 0) < 0) {
> mlog_errno(-EIO);
> brelse(*bh);
> *bh = NULL;