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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_UNALIGNED flag
Date: Mon, 18 Jan 2021 20:35:15 +0100
Message-ID: <20210118193516.2915706-11-hch@lst.de> (raw)
In-Reply-To: <20210118193516.2915706-1-hch@lst.de>

Add a flag to signal an I/O that is not file system block aligned.

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 32dbbf7dd4aadb..d93019ee4c9e3e 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_UNALIGNED) {
+		ret = -EAGAIN;
+		if (pos >= dio->i_size)
+			goto out_free_dio;
+		iomap_flags |= IOMAP_UNALIGNED;
+	}
+
 	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 b322598dc10ec0..2fa94ec9583d0a 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_UNALIGNED		(1 << 6) /* do not allocate blocks */
 
 struct iomap_ops {
 	/*
@@ -262,6 +263,13 @@ struct iomap_dio_ops {
  */
 #define IOMAP_DIO_FORCE_WAIT	(1 << 0)
 
+/*
+ * Direct I/O that is not aligned to the file system block.  Do not allocate
+ * blocks and do not zero partial blocks, fall back to the caller by returning
+ * -EAGAIN instead.
+ */
+#define IOMAP_DIO_UNALIGNED	(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 flags);
-- 
2.29.2


  parent reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-18 19:35 reduce sub-block DIO serialisation v2 Christoph Hellwig
2021-01-18 19:35 ` [PATCH 01/11] xfs: factor out a xfs_ilock_iocb helper Christoph Hellwig
2021-01-20 18:41   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 02/11] xfs: make xfs_file_aio_write_checks IOCB_NOWAIT-aware Christoph Hellwig
     [not found]   ` <CACz=WeeaqMrGM53pJF0C_Wt2JuavTOnOV26-osPviYLUpqUmFw@mail.gmail.com>
2021-01-20 16:28     ` Christoph Hellwig
2021-01-20 18:42   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 03/11] xfs: cleanup the read/write helper naming Christoph Hellwig
2021-01-19 15:23   ` Brian Foster
2021-01-20 18:43   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 04/11] xfs: remove the buffered I/O fallback assert Christoph Hellwig
2021-01-19 15:23   ` Brian Foster
2021-01-20 18:43   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 05/11] xfs: simplify the read/write tracepoints Christoph Hellwig
2021-01-19 15:23   ` Brian Foster
2021-01-20 18:45   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 06/11] xfs: improve the reflink_bounce_dio_write tracepoint Christoph Hellwig
2021-01-19 15:23   ` Brian Foster
2021-01-20 18:45   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 07/11] xfs: split unaligned DIO write code out Christoph Hellwig
2021-01-19 15:23   ` Brian Foster
2021-01-20 18:46   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 08/11] iomap: rename the flags variable in __iomap_dio_rw Christoph Hellwig
2021-01-18 20:34   ` Dave Chinner
2021-01-19 15:23   ` Brian Foster
2021-01-20 18:46   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 09/11] iomap: pass a flags argument to iomap_dio_rw Christoph Hellwig
2021-01-19 15:23   ` Brian Foster
2021-01-20 18:17   ` Darrick J. Wong
2021-01-20 18:35     ` Christoph Hellwig
2021-01-18 19:35 ` Christoph Hellwig [this message]
2021-01-18 20:45   ` [PATCH 10/11] iomap: add a IOMAP_DIO_UNALIGNED flag Dave Chinner
2021-01-18 21:41   ` Matthew Wilcox
2021-01-20 16:40     ` Christoph Hellwig
2021-01-20 18:47   ` Darrick J. Wong
2021-01-18 19:35 ` [PATCH 11/11] xfs: reduce exclusive locking on unaligned dio Christoph Hellwig
2021-01-18 20:55   ` Dave Chinner
2021-01-20 16:36     ` Christoph Hellwig
2021-01-20 18:40   ` Darrick J. Wong
2021-01-20 18:44     ` Christoph Hellwig
2021-01-20 19:58       ` Darrick J. Wong

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