[Ocfs2-devel] [PATCH] ocfs2: avoid direct write if we fall back to buffered
Sunil Mushran
sunil.mushran at oracle.com
Thu Apr 8 11:41:26 PDT 2010
I cannot read the bugzilla. Now it maybe that that bz
cannot be made public. That's ok. But if that's the case,
can you explain the problem encountered. I am not qs
the fix... rather trying to understand why this has not
been reported before.
Li Dongyang wrote:
> when we fall back to buffered write from direct write, we call
> __generic_file_aio_write but that will end up doing direct write
> even we are only prepared to do buffered write because the file
> has O_DIRECT flag set. This is a fix for
> https://bugzilla.novell.com/show_bug.cgi?id=591039
>
>
> Signed-off-by: Li Dongyang <lidongyang at novell.com>
> ---
> fs/ocfs2/file.c | 27 +++++++++++++++++----------
> 1 files changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index de059f4..707f2a2 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -1973,18 +1973,24 @@ relock:
> /* communicate with ocfs2_dio_end_io */
> ocfs2_iocb_set_rw_locked(iocb, rw_level);
>
> - if (direct_io) {
> - ret = generic_segment_checks(iov, &nr_segs, &ocount,
> - VERIFY_READ);
> - if (ret)
> - goto out_dio;
> + ret = generic_segment_checks(iov, &nr_segs, &ocount,
> + VERIFY_READ);
> + if (ret)
> + goto out_dio;
>
> - count = ocount;
> - ret = generic_write_checks(file, ppos, &count,
> + count = ocount;
> + ret = generic_write_checks(file, ppos, &count,
> S_ISBLK(inode->i_mode));
> - if (ret)
> - goto out_dio;
> + if (ret)
> + goto out_dio;
> +
> + ret = file_remove_suid(file);
> + if (ret)
> + goto out_dio;
>
> + file_update_time(file);
> +
> + if (direct_io) {
> written = generic_file_direct_write(iocb, iov, &nr_segs, *ppos,
> ppos, count, ocount);
> if (written < 0) {
> @@ -1999,7 +2005,8 @@ relock:
> goto out_dio;
> }
> } else {
> - written = __generic_file_aio_write(iocb, iov, nr_segs, ppos);
> + written = generic_file_buffered_write(iocb, iov, nr_segs,
> + *ppos, ppos, count, 0);
> }
>
> out_dio:
>
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