From: Christoph Hellwig <hch@lst.de>
To: linux-xfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, avi@scylladb.com
Subject: [PATCH 10/11] iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag
Date: Thu, 21 Jan 2021 09:59:05 +0100 [thread overview]
Message-ID: <20210121085906.322712-11-hch@lst.de> (raw)
In-Reply-To: <20210121085906.322712-1-hch@lst.de>
Add a flag to signal an only pure overwrites are allowed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
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 9:12 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 ` Christoph Hellwig [this message]
2021-01-21 9:32 ` [PATCH 10/11] iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag Dave Chinner
2021-01-21 13:32 ` Brian Foster
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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