From: Brian Foster <bfoster@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
avi@scylladb.com
Subject: Re: [PATCH 10/11] iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag
Date: Thu, 21 Jan 2021 08:32:54 -0500 [thread overview]
Message-ID: <20210121133254.GA1793795@bfoster> (raw)
In-Reply-To: <20210121085906.322712-11-hch@lst.de>
On Thu, Jan 21, 2021 at 09:59:05AM +0100, Christoph Hellwig wrote:
> Add a flag to signal an only pure overwrites are allowed.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
Agreed that the explicit flag name is much more clear:
Reviewed-by: Brian Foster <bfoster@redhat.com>
> fs/iomap/direct-io.c | 7 +++++++
> include/linux/iomap.h | 8 ++++++++
> 2 files changed, 15 insertions(+)
>
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 947343730e2c93..65d32364345d22 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -485,6 +485,13 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> iomap_flags |= IOMAP_NOWAIT;
> }
>
> + if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {
> + ret = -EAGAIN;
> + if (pos >= dio->i_size || pos + count > dio->i_size)
> + goto out_free_dio;
> + iomap_flags |= IOMAP_OVERWRITE_ONLY;
> + }
> +
> ret = filemap_write_and_wait_range(mapping, pos, end);
> if (ret)
> goto out_free_dio;
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index be4e1e1e01e801..cfa20afd7d5b87 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -122,6 +122,7 @@ struct iomap_page_ops {
> #define IOMAP_FAULT (1 << 3) /* mapping for page fault */
> #define IOMAP_DIRECT (1 << 4) /* direct I/O */
> #define IOMAP_NOWAIT (1 << 5) /* do not block */
> +#define IOMAP_OVERWRITE_ONLY (1 << 6) /* purely overwrites allowed */
>
> struct iomap_ops {
> /*
> @@ -262,6 +263,13 @@ struct iomap_dio_ops {
> */
> #define IOMAP_DIO_FORCE_WAIT (1 << 0)
>
> +/*
> + * Do not allocate blocks or zero partial blocks, but instead fall back to
> + * the caller by returning -EAGAIN. Used to optimize direct I/O writes that
> + * are not aligned to the file system block size.
> + */
> +#define IOMAP_DIO_OVERWRITE_ONLY (1 << 1)
> +
> ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
> unsigned int dio_flags);
> --
> 2.29.2
>
next prev parent reply other threads:[~2021-01-21 14:54 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 8:58 reduce sub-block DIO serialisation v3 Christoph Hellwig
2021-01-21 8:58 ` [PATCH 01/11] xfs: factor out a xfs_ilock_iocb helper Christoph Hellwig
2021-01-21 8:58 ` [PATCH 02/11] xfs: make xfs_file_aio_write_checks IOCB_NOWAIT-aware Christoph Hellwig
2021-01-21 8:58 ` [PATCH 03/11] xfs: cleanup the read/write helper naming Christoph Hellwig
2021-01-21 8:58 ` [PATCH 04/11] xfs: remove the buffered I/O fallback assert Christoph Hellwig
2021-01-21 8:59 ` [PATCH 05/11] xfs: simplify the read/write tracepoints Christoph Hellwig
2021-01-21 8:59 ` [PATCH 06/11] xfs: improve the reflink_bounce_dio_write tracepoint Christoph Hellwig
2021-01-21 8:59 ` [PATCH 07/11] xfs: split unaligned DIO write code out Christoph Hellwig
2021-01-21 8:59 ` [PATCH 08/11] iomap: rename the flags variable in __iomap_dio_rw Christoph Hellwig
2021-01-21 8:59 ` [PATCH 09/11] iomap: pass a flags argument to iomap_dio_rw Christoph Hellwig
2021-01-21 9:30 ` Dave Chinner
2021-01-21 18:53 ` Darrick J. Wong
2021-01-21 8:59 ` [PATCH 10/11] iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag Christoph Hellwig
2021-01-21 9:32 ` Dave Chinner
2021-01-21 13:32 ` Brian Foster [this message]
2021-01-21 18:55 ` Darrick J. Wong
2021-01-21 8:59 ` [PATCH 11/11] xfs: reduce exclusive locking on unaligned dio Christoph Hellwig
2021-01-21 9:35 ` Dave Chinner
2021-01-22 10:20 ` Christoph Hellwig
2021-01-21 13:33 ` Brian Foster
2021-01-21 19:01 ` Darrick J. Wong
2021-01-22 16:20 reduce sub-block DIO serialisation v4 Christoph Hellwig
2021-01-22 16:20 ` [PATCH 10/11] iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag Christoph Hellwig
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