[PATCH 09/10] fs: add RWF_DSYNC aand RWF_SYNC

[PATCH 09/10] fs: add RWF_DSYNC aand RWF_SYNC

[Christoph Hellwig]

This is the per-I/O equivalent of O_DSYNC and O_SYNC, and very useful for
all kinds of file servers and storage targets.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/read_write.c         | 6 +++++-
 include/uapi/linux/fs.h | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index cf377cf..3729d8d 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -698,12 +698,16 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
 	struct kiocb kiocb;
 	ssize_t ret;
 
-	if (flags & ~RWF_HIPRI)
+	if (flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC))
 		return -EOPNOTSUPP;
 
 	init_sync_kiocb(&kiocb, filp);
 	if (flags & RWF_HIPRI)
 		kiocb.ki_flags |= IOCB_HIPRI;
+	if (flags & RWF_DSYNC)
+		kiocb.ki_flags |= IOCB_DSYNC;
+	if (flags & RWF_SYNC)
+		kiocb.ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
 	kiocb.ki_pos = *ppos;
 
 	ret = fn(&kiocb, iter);
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index a079d50..7f067fe 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -324,5 +324,7 @@ struct fscrypt_policy {
 
 /* flags for preadv2/pwritev2: */
 #define RWF_HIPRI			0x00000001 /* high priority request, poll if possible */
+#define RWF_DSYNC			0x00000002 /* per-IO O_DSYNC */
+#define RWF_SYNC			0x00000002 /* per-IO O_SYNC */
 
 #endif /* _UAPI_LINUX_FS_H */
-- 
2.1.4

add RWF_(D)SYNC flag to preadv2/pwritev2 V2

[Christoph Hellwig]

Add per-I/O sync flags, which are very useful for all kinds of file servers
or storage targets.  To properly do this refactor lots of direct I/O code
to not pass pointless argument, which makes the whole series a net negative
in terms of lines of code.

Changes since V1:
 - fix RWF_SYNC defintion
 - fix a comment

[PATCH 01/10] filemap: remove pos variables in generic_file_read_iter

[Christoph Hellwig]

Just use ki_pos directly to make everyones life easier.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/filemap.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index f2479af..5885925 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1838,8 +1838,6 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	ssize_t retval = 0;
-	loff_t *ppos = &iocb->ki_pos;
-	loff_t pos = *ppos;
 	size_t count = iov_iter_count(iter);
 
 	if (!count)
@@ -1851,15 +1849,16 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 		loff_t size;
 
 		size = i_size_read(inode);
-		retval = filemap_write_and_wait_range(mapping, pos,
-					pos + count - 1);
+		retval = filemap_write_and_wait_range(mapping, iocb->ki_pos,
+					iocb->ki_pos + count - 1);
 		if (!retval) {
 			struct iov_iter data = *iter;
-			retval = mapping->a_ops->direct_IO(iocb, &data, pos);
+			retval = mapping->a_ops->direct_IO(iocb, &data,
+					iocb->ki_pos);
 		}
 
 		if (retval > 0) {
-			*ppos = pos + retval;
+			iocb->ki_pos += retval;
 			iov_iter_advance(iter, retval);
 		}
 
@@ -1872,14 +1871,14 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 		 * the rest of the read.  Buffered reads will not work for
 		 * DAX files, so don't bother trying.
 		 */
-		if (retval < 0 || !iov_iter_count(iter) || *ppos >= size ||
+		if (retval < 0 || !iov_iter_count(iter) || iocb->ki_pos >= size ||
 		    IS_DAX(inode)) {
 			file_accessed(file);
 			goto out;
 		}
 	}
 
-	retval = do_generic_file_read(file, ppos, iter, retval);
+	retval = do_generic_file_read(file, &iocb->ki_pos, iter, retval);
 out:
 	return retval;
 }
-- 
2.1.4

[PATCH 02/10] filemap: remove the pos argument to generic_file_direct_write

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/btrfs/file.c    | 9 ++++-----
 fs/fuse/file.c     | 2 +-
 include/linux/fs.h | 2 +-
 mm/filemap.c       | 5 +++--
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index cf31a60..d28ec60 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1703,18 +1703,17 @@ again:
 	return num_written ? num_written : ret;
 }
 
-static ssize_t __btrfs_direct_write(struct kiocb *iocb,
-				    struct iov_iter *from,
-				    loff_t pos)
+static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
+	loff_t pos = iocb->ki_pos;
 	ssize_t written;
 	ssize_t written_buffered;
 	loff_t endbyte;
 	int err;
 
-	written = generic_file_direct_write(iocb, from, pos);
+	written = generic_file_direct_write(iocb, from);
 
 	if (written < 0 || !iov_iter_count(from))
 		return written;
@@ -1832,7 +1831,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 		atomic_inc(&BTRFS_I(inode)->sync_writers);
 
 	if (iocb->ki_flags & IOCB_DIRECT) {
-		num_written = __btrfs_direct_write(iocb, from, pos);
+		num_written = __btrfs_direct_write(iocb, from);
 	} else {
 		num_written = __btrfs_buffered_write(file, from, pos);
 		if (num_written > 0)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 719924d..7e8c460 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1186,7 +1186,7 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 	if (iocb->ki_flags & IOCB_DIRECT) {
 		loff_t pos = iocb->ki_pos;
-		written = generic_file_direct_write(iocb, from, pos);
+		written = generic_file_direct_write(iocb, from);
 		if (written < 0 || !iov_iter_count(from))
 			goto out;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 304991a..a06c7c8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2693,7 +2693,7 @@ extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
-extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *, loff_t);
+extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
 
 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos);
diff --git a/mm/filemap.c b/mm/filemap.c
index 5885925..e7108c3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2499,11 +2499,12 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
 EXPORT_SYMBOL(pagecache_write_end);
 
 ssize_t
-generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
+generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file	*file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode	*inode = mapping->host;
+	loff_t		pos = iocb->ki_pos;
 	ssize_t		written;
 	size_t		write_len;
 	pgoff_t		end;
@@ -2717,7 +2718,7 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (iocb->ki_flags & IOCB_DIRECT) {
 		loff_t pos, endbyte;
 
-		written = generic_file_direct_write(iocb, from, iocb->ki_pos);
+		written = generic_file_direct_write(iocb, from);
 		/*
 		 * If the write stopped short of completing, fall back to
 		 * buffered writes.  Some filesystems do this for writes to
-- 
2.1.4

[PATCH 03/10] xfs: eliminate the pos variable in xfs_file_dio_aio_write

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_file.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 569938a..92f72fb 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -718,18 +718,19 @@ xfs_file_dio_aio_write(
 	int			unaligned_io = 0;
 	int			iolock;
 	size_t			count = iov_iter_count(from);
-	loff_t			pos = iocb->ki_pos;
 	loff_t			end;
 	struct iov_iter		data;
 	struct xfs_buftarg	*target = XFS_IS_REALTIME_INODE(ip) ?
 					mp->m_rtdev_targp : mp->m_ddev_targp;
 
 	/* DIO must be aligned to device logical sector size */
-	if (!IS_DAX(inode) && ((pos | count) & target->bt_logical_sectormask))
+	if (!IS_DAX(inode) &&
+	    ((iocb->ki_pos | count) & target->bt_logical_sectormask))
 		return -EINVAL;
 
 	/* "unaligned" here means not aligned to a filesystem block */
-	if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
+	if ((iocb->ki_pos & mp->m_blockmask) ||
+	    ((iocb->ki_pos + count) & mp->m_blockmask))
 		unaligned_io = 1;
 
 	/*
@@ -760,8 +761,7 @@ xfs_file_dio_aio_write(
 	if (ret)
 		goto out;
 	count = iov_iter_count(from);
-	pos = iocb->ki_pos;
-	end = pos + count - 1;
+	end = iocb->ki_pos + count - 1;
 
 	/*
 	 * See xfs_file_read_iter() for why we do a full-file flush here.
@@ -794,19 +794,18 @@ xfs_file_dio_aio_write(
 	trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
 
 	data = *from;
-	ret = mapping->a_ops->direct_IO(iocb, &data, pos);
+	ret = mapping->a_ops->direct_IO(iocb, &data, iocb->ki_pos);
 
 	/* see generic_file_direct_write() for why this is necessary */
 	if (mapping->nrpages) {
 		invalidate_inode_pages2_range(mapping,
-					      pos >> PAGE_SHIFT,
+					      iocb->ki_pos >> PAGE_SHIFT,
 					      end >> PAGE_SHIFT);
 	}
 
 	if (ret > 0) {
-		pos += ret;
+		iocb->ki_pos += ret;
 		iov_iter_advance(from, ret);
-		iocb->ki_pos = pos;
 	}
 out:
 	xfs_rw_iunlock(ip, iolock);
-- 
2.1.4

[PATCH 04/10] direct-io: eliminate the offset argument to ->direct_IO

[Christoph Hellwig]

Including blkdev_direct_IO and dax_do_io.  It has to be ki_pos to actually
work, so eliminate the superflous argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 Documentation/filesystems/Locking          |  2 +-
 Documentation/filesystems/vfs.txt          |  2 +-
 drivers/staging/lustre/lustre/llite/rw26.c |  4 ++--
 fs/9p/vfs_addr.c                           |  3 ++-
 fs/affs/file.c                             |  5 +++--
 fs/block_dev.c                             |  6 +++---
 fs/btrfs/inode.c                           |  6 +++---
 fs/ceph/addr.c                             |  3 +--
 fs/cifs/file.c                             |  2 +-
 fs/dax.c                                   |  4 ++--
 fs/direct-io.c                             |  7 ++++---
 fs/exofs/inode.c                           |  3 +--
 fs/ext2/inode.c                            |  8 ++++----
 fs/ext4/ext4.h                             |  3 +--
 fs/ext4/indirect.c                         | 12 ++++++------
 fs/ext4/inode.c                            | 18 +++++++++---------
 fs/f2fs/data.c                             |  6 +++---
 fs/fat/inode.c                             |  6 +++---
 fs/fuse/file.c                             |  3 ++-
 fs/gfs2/aops.c                             |  6 +++---
 fs/hfs/inode.c                             |  7 +++----
 fs/hfsplus/inode.c                         |  7 +++----
 fs/jfs/inode.c                             |  7 +++----
 fs/nfs/direct.c                            | 17 +++++++----------
 fs/nfs/file.c                              |  2 +-
 fs/nilfs2/inode.c                          |  4 ++--
 fs/ocfs2/aops.c                            |  9 ++++-----
 fs/reiserfs/inode.c                        |  7 +++----
 fs/udf/file.c                              |  3 +--
 fs/udf/inode.c                             |  7 +++----
 fs/xfs/xfs_aops.c                          |  7 +++----
 fs/xfs/xfs_file.c                          |  2 +-
 include/linux/dax.h                        |  2 +-
 include/linux/fs.h                         |  9 ++++-----
 include/linux/nfs_fs.h                     |  5 ++---
 mm/filemap.c                               |  5 ++---
 mm/page_io.c                               |  2 +-
 37 files changed, 99 insertions(+), 112 deletions(-)

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 619af9b..75eea7c 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -194,7 +194,7 @@ prototypes:
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, int);
 	void (*freepage)(struct page *);
-	int (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset);
+	int (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 	int (*migratepage)(struct address_space *, struct page *, struct page *);
 	int (*launder_page)(struct page *);
 	int (*is_partially_uptodate)(struct page *, unsigned long, unsigned long);
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 4164bd6..c61a223 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -591,7 +591,7 @@ struct address_space_operations {
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, int);
 	void (*freepage)(struct page *);
-	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset);
+	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 	/* migrate the contents of a page to the specified target */
 	int (*migratepage) (struct page *, struct page *);
 	int (*launder_page) (struct page *);
diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c
index 69aa15e..0c3459c 100644
--- a/drivers/staging/lustre/lustre/llite/rw26.c
+++ b/drivers/staging/lustre/lustre/llite/rw26.c
@@ -358,14 +358,14 @@ static ssize_t ll_direct_IO_26_seg(const struct lu_env *env, struct cl_io *io,
  */
 #define MAX_DIO_SIZE ((KMALLOC_MAX_SIZE / sizeof(struct brw_page) *	  \
 		       PAGE_SIZE) & ~(DT_MAX_BRW_SIZE - 1))
-static ssize_t ll_direct_IO_26(struct kiocb *iocb, struct iov_iter *iter,
-			       loff_t file_offset)
+static ssize_t ll_direct_IO_26(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct lu_env *env;
 	struct cl_io *io;
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	struct ccc_object *obj = cl_inode2ccc(inode);
+	loff_t file_offset = iocb->ki_pos;
 	ssize_t count = iov_iter_count(iter);
 	ssize_t tot_bytes = 0, result = 0;
 	struct ll_inode_info *lli = ll_i2info(inode);
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index ac9225e..c37fb9c 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -245,9 +245,10 @@ static int v9fs_launder_page(struct page *page)
  *
  */
 static ssize_t
-v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
+v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
+	loff_t pos = iocb->ki_pos;
 	ssize_t n;
 	int err = 0;
 	if (iov_iter_rw(iter) == WRITE) {
diff --git a/fs/affs/file.c b/fs/affs/file.c
index 0cde550..0deec9c 100644
--- a/fs/affs/file.c
+++ b/fs/affs/file.c
@@ -389,12 +389,13 @@ static void affs_write_failed(struct address_space *mapping, loff_t to)
 }
 
 static ssize_t
-affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
+affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	ssize_t ret;
 
 	if (iov_iter_rw(iter) == WRITE) {
@@ -404,7 +405,7 @@ affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 			return 0;
 	}
 
-	ret = blockdev_direct_IO(iocb, inode, iter, offset, affs_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 		affs_write_failed(mapping, offset + count);
 	return ret;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 20a2c02..9e1f3fe 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -162,15 +162,15 @@ static struct inode *bdev_file_inode(struct file *file)
 }
 
 static ssize_t
-blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
+blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = bdev_file_inode(file);
 
 	if (IS_DAX(inode))
-		return dax_do_io(iocb, inode, iter, offset, blkdev_get_block,
+		return dax_do_io(iocb, inode, iter, blkdev_get_block,
 				NULL, DIO_SKIP_DIO_COUNT);
-	return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset,
+	return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter,
 				    blkdev_get_block, NULL, NULL,
 				    DIO_SKIP_DIO_COUNT);
 }
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2aaba58..352d4e1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8541,13 +8541,13 @@ out:
 	return retval;
 }
 
-static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			       loff_t offset)
+static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_dio_data dio_data = { 0 };
+	loff_t offset = iocb->ki_pos;
 	size_t count = 0;
 	int flags = 0;
 	bool wakeup = true;
@@ -8607,7 +8607,7 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 
 	ret = __blockdev_direct_IO(iocb, inode,
 				   BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
-				   iter, offset, btrfs_get_blocks_direct, NULL,
+				   iter, btrfs_get_blocks_direct, NULL,
 				   btrfs_submit_direct, flags);
 	if (iov_iter_rw(iter) == WRITE) {
 		current->journal_info = NULL;
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 4801571..43098cd 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1292,8 +1292,7 @@ static int ceph_write_end(struct file *file, struct address_space *mapping,
  * intercept O_DIRECT reads and writes early, this function should
  * never get called.
  */
-static ssize_t ceph_direct_io(struct kiocb *iocb, struct iov_iter *iter,
-			      loff_t pos)
+static ssize_t ceph_direct_io(struct kiocb *iocb, struct iov_iter *iter)
 {
 	WARN_ON(1);
 	return -EINVAL;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c03d074..cb070aa 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3854,7 +3854,7 @@ void cifs_oplock_break(struct work_struct *work)
  * Direct IO is not yet supported in the cached mode. 
  */
 static ssize_t
-cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
+cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter)
 {
         /*
          * FIXME
diff --git a/fs/dax.c b/fs/dax.c
index 75ba46d..0dbe4e0 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -244,7 +244,6 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
  * @iocb: The control block for this I/O
  * @inode: The file which the I/O is directed at
  * @iter: The addresses to do I/O from or to
- * @pos: The file offset where the I/O starts
  * @get_block: The filesystem method used to translate file offsets to blocks
  * @end_io: A filesystem callback for I/O completion
  * @flags: See below
@@ -257,11 +256,12 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
  * is in progress.
  */
 ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
-		  struct iov_iter *iter, loff_t pos, get_block_t get_block,
+		  struct iov_iter *iter, get_block_t get_block,
 		  dio_iodone_t end_io, int flags)
 {
 	struct buffer_head bh;
 	ssize_t retval = -EINVAL;
+	loff_t pos = iocb->ki_pos;
 	loff_t end = pos + iov_iter_count(iter);
 
 	memset(&bh, 0, sizeof(bh));
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 4720377..8949d3e 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1113,7 +1113,7 @@ static inline int drop_refcount(struct dio *dio)
 static inline ssize_t
 do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 		      struct block_device *bdev, struct iov_iter *iter,
-		      loff_t offset, get_block_t get_block, dio_iodone_t end_io,
+		      get_block_t get_block, dio_iodone_t end_io,
 		      dio_submit_t submit_io, int flags)
 {
 	unsigned i_blkbits = ACCESS_ONCE(inode->i_blkbits);
@@ -1121,6 +1121,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 	unsigned blocksize_mask = (1 << blkbits) - 1;
 	ssize_t retval = -EINVAL;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	loff_t end = offset + count;
 	struct dio *dio;
 	struct dio_submit sdio = { 0, };
@@ -1328,7 +1329,7 @@ out:
 
 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 			     struct block_device *bdev, struct iov_iter *iter,
-			     loff_t offset, get_block_t get_block,
+			     get_block_t get_block,
 			     dio_iodone_t end_io, dio_submit_t submit_io,
 			     int flags)
 {
@@ -1344,7 +1345,7 @@ ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 	prefetch(bdev->bd_queue);
 	prefetch((char *)bdev->bd_queue + SMP_CACHE_BYTES);
 
-	return do_blockdev_direct_IO(iocb, inode, bdev, iter, offset, get_block,
+	return do_blockdev_direct_IO(iocb, inode, bdev, iter, get_block,
 				     end_io, submit_io, flags);
 }
 
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 49e1bd0..9dc4c6d 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -960,8 +960,7 @@ static void exofs_invalidatepage(struct page *page, unsigned int offset,
 
 
  /* TODO: Should be easy enough to do proprly */
-static ssize_t exofs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			       loff_t offset)
+static ssize_t exofs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	return 0;
 }
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 6bd58e6..b675610 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -854,20 +854,20 @@ static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
 }
 
 static ssize_t
-ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
+ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	ssize_t ret;
 
 	if (IS_DAX(inode))
-		ret = dax_do_io(iocb, inode, iter, offset, ext2_get_block, NULL,
+		ret = dax_do_io(iocb, inode, iter, ext2_get_block, NULL,
 				DIO_LOCKING);
 	else
-		ret = blockdev_direct_IO(iocb, inode, iter, offset,
-					 ext2_get_block);
+		ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block);
 	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 		ext2_write_failed(mapping, offset + count);
 	return ret;
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 7ccba1a..73b1cb2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2556,8 +2556,7 @@ extern int ext4_get_next_extent(struct inode *inode, ext4_lblk_t lblk,
 /* indirect.c */
 extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
 				struct ext4_map_blocks *map, int flags);
-extern ssize_t ext4_ind_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-				  loff_t offset);
+extern ssize_t ext4_ind_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
 extern int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock);
 extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks);
 extern void ext4_ind_truncate(handle_t *, struct inode *inode);
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 3027fa6..627b7e8 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -659,12 +659,12 @@ out:
  * crashes then stale disk data _may_ be exposed inside the file. But current
  * VFS code falls back into buffered path in that case so we are safe.
  */
-ssize_t ext4_ind_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			   loff_t offset)
+ssize_t ext4_ind_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	struct ext4_inode_info *ei = EXT4_I(inode);
+	loff_t offset = iocb->ki_pos;
 	handle_t *handle;
 	ssize_t ret;
 	int orphan = 0;
@@ -707,21 +707,21 @@ retry:
 			goto locked;
 		}
 		if (IS_DAX(inode))
-			ret = dax_do_io(iocb, inode, iter, offset,
+			ret = dax_do_io(iocb, inode, iter,
 					ext4_dio_get_block, NULL, 0);
 		else
 			ret = __blockdev_direct_IO(iocb, inode,
 						   inode->i_sb->s_bdev, iter,
-						   offset, ext4_dio_get_block,
+						   ext4_dio_get_block,
 						   NULL, NULL, 0);
 		inode_dio_end(inode);
 	} else {
 locked:
 		if (IS_DAX(inode))
-			ret = dax_do_io(iocb, inode, iter, offset,
+			ret = dax_do_io(iocb, inode, iter,
 					ext4_dio_get_block, NULL, DIO_LOCKING);
 		else
-			ret = blockdev_direct_IO(iocb, inode, iter, offset,
+			ret = blockdev_direct_IO(iocb, inode, iter,
 						 ext4_dio_get_block);
 
 		if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4f7043b..796c321 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3336,12 +3336,12 @@ static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
  * if the machine crashes during the write.
  *
  */
-static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-				  loff_t offset)
+static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	ssize_t ret;
+	loff_t offset = iocb->ki_pos;
 	size_t count = iov_iter_count(iter);
 	int overwrite = 0;
 	get_block_t *get_block_func = NULL;
@@ -3350,7 +3350,7 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 
 	/* Use the old path for reads and writes beyond i_size. */
 	if (iov_iter_rw(iter) != WRITE || final_size > inode->i_size)
-		return ext4_ind_direct_IO(iocb, iter, offset);
+		return ext4_ind_direct_IO(iocb, iter);
 
 	BUG_ON(iocb->private == NULL);
 
@@ -3402,11 +3402,11 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode));
 #endif
 	if (IS_DAX(inode))
-		ret = dax_do_io(iocb, inode, iter, offset, get_block_func,
+		ret = dax_do_io(iocb, inode, iter, get_block_func,
 				ext4_end_io_dio, dio_flags);
 	else
 		ret = __blockdev_direct_IO(iocb, inode,
-					   inode->i_sb->s_bdev, iter, offset,
+					   inode->i_sb->s_bdev, iter,
 					   get_block_func,
 					   ext4_end_io_dio, NULL, dio_flags);
 
@@ -3433,12 +3433,12 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	return ret;
 }
 
-static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			      loff_t offset)
+static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	ssize_t ret;
 
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
@@ -3458,9 +3458,9 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 
 	trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-		ret = ext4_ext_direct_IO(iocb, iter, offset);
+		ret = ext4_ext_direct_IO(iocb, iter);
 	else
-		ret = ext4_ind_direct_IO(iocb, iter, offset);
+		ret = ext4_ind_direct_IO(iocb, iter);
 	trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
 	return ret;
 }
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 53fec08..a4c5da5 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1655,12 +1655,12 @@ static int check_direct_IO(struct inode *inode, struct iov_iter *iter,
 	return 0;
 }
 
-static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			      loff_t offset)
+static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct address_space *mapping = iocb->ki_filp->f_mapping;
 	struct inode *inode = mapping->host;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	int err;
 
 	err = check_direct_IO(inode, iter, offset);
@@ -1672,7 +1672,7 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 
 	trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 
-	err = blockdev_direct_IO(iocb, inode, iter, offset, get_data_block_dio);
+	err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio);
 	if (err < 0 && iov_iter_rw(iter) == WRITE)
 		f2fs_write_failed(mapping, offset + count);
 
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 2262810..3bcf579 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -244,13 +244,13 @@ static int fat_write_end(struct file *file, struct address_space *mapping,
 	return err;
 }
 
-static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			     loff_t offset)
+static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	ssize_t ret;
 
 	if (iov_iter_rw(iter) == WRITE) {
@@ -272,7 +272,7 @@ static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	 * FAT need to use the DIO_LOCKING for avoiding the race
 	 * condition of fat_get_block() and ->truncate().
 	 */
-	ret = blockdev_direct_IO(iocb, inode, iter, offset, fat_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
 	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 		fat_write_failed(mapping, offset + count);
 
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 7e8c460..0227907 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2837,7 +2837,7 @@ static inline loff_t fuse_round_up(loff_t off)
 }
 
 static ssize_t
-fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
+fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	DECLARE_COMPLETION_ONSTACK(wait);
 	ssize_t ret = 0;
@@ -2848,6 +2848,7 @@ fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 	struct inode *inode;
 	loff_t i_size;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	struct fuse_io_priv *io;
 	bool is_sync = is_sync_kiocb(iocb);
 
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 1bbbee9..8524c0e 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -1042,13 +1042,13 @@ static int gfs2_ok_for_dio(struct gfs2_inode *ip, loff_t offset)
 
 
 
-static ssize_t gfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			      loff_t offset)
+static ssize_t gfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	struct address_space *mapping = inode->i_mapping;
 	struct gfs2_inode *ip = GFS2_I(inode);
+	loff_t offset = iocb->ki_pos;
 	struct gfs2_holder gh;
 	int rv;
 
@@ -1099,7 +1099,7 @@ static ssize_t gfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	}
 
 	rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
-				  offset, gfs2_get_block_direct, NULL, NULL, 0);
+				  gfs2_get_block_direct, NULL, NULL, 0);
 out:
 	gfs2_glock_dq(&gh);
 	gfs2_holder_uninit(&gh);
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index cb1e5fa..c82331a 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -124,8 +124,7 @@ static int hfs_releasepage(struct page *page, gfp_t mask)
 	return res ? try_to_free_buffers(page) : 0;
 }
 
-static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			     loff_t offset)
+static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -133,7 +132,7 @@ static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(iocb, inode, iter, offset, hfs_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, hfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
@@ -141,7 +140,7 @@ static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	 */
 	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + count;
+		loff_t end = iocb->ki_pos + count;
 
 		if (end > isize)
 			hfs_write_failed(mapping, end);
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index b28f398..2ad34a5 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -122,8 +122,7 @@ static int hfsplus_releasepage(struct page *page, gfp_t mask)
 	return res ? try_to_free_buffers(page) : 0;
 }
 
-static ssize_t hfsplus_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-				 loff_t offset)
+static ssize_t hfsplus_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -131,7 +130,7 @@ static ssize_t hfsplus_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(iocb, inode, iter, offset, hfsplus_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, hfsplus_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
@@ -139,7 +138,7 @@ static ssize_t hfsplus_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	 */
 	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + count;
+		loff_t end = iocb->ki_pos + count;
 
 		if (end > isize)
 			hfsplus_write_failed(mapping, end);
diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index 9d9bae6..f6a2a78 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -332,8 +332,7 @@ static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
 	return generic_block_bmap(mapping, block, jfs_get_block);
 }
 
-static ssize_t jfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			     loff_t offset)
+static ssize_t jfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -341,7 +340,7 @@ static ssize_t jfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(iocb, inode, iter, offset, jfs_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, jfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
@@ -349,7 +348,7 @@ static ssize_t jfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	 */
 	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + count;
+		loff_t end = iocb->ki_pos + count;
 
 		if (end > isize)
 			jfs_write_failed(mapping, end);
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index c93826e..346b5d8 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -250,7 +250,7 @@ static int nfs_direct_cmp_commit_data_verf(struct nfs_direct_req *dreq,
  * shunt off direct read and write requests before the VFS gets them,
  * so this method is only ever called for swap.
  */
-ssize_t nfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
+ssize_t nfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct inode *inode = iocb->ki_filp->f_mapping->host;
 
@@ -261,7 +261,7 @@ ssize_t nfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
 	VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE);
 
 	if (iov_iter_rw(iter) == READ)
-		return nfs_file_direct_read(iocb, iter, pos);
+		return nfs_file_direct_read(iocb, iter);
 	return nfs_file_direct_write(iocb, iter);
 }
 
@@ -545,7 +545,6 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
  * nfs_file_direct_read - file direct read operation for NFS files
  * @iocb: target I/O control block
  * @iter: vector of user buffers into which to read data
- * @pos: byte offset in file where reading starts
  *
  * We use this function for direct reads instead of calling
  * generic_file_aio_read() in order to avoid gfar's check to see if
@@ -561,8 +560,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
  * client must read the updated atime from the server back into its
  * cache.
  */
-ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
-				loff_t pos)
+ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -574,7 +572,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
 	nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
 
 	dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",
-		file, count, (long long) pos);
+		file, count, (long long) iocb->ki_pos);
 
 	result = 0;
 	if (!count)
@@ -594,7 +592,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
 
 	dreq->inode = inode;
 	dreq->bytes_left = count;
-	dreq->io_start = pos;
+	dreq->io_start = iocb->ki_pos;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
 	l_ctx = nfs_get_lock_context(dreq->ctx);
 	if (IS_ERR(l_ctx)) {
@@ -606,14 +604,14 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
 		dreq->iocb = iocb;
 
 	NFS_I(inode)->read_io += count;
-	result = nfs_direct_read_schedule_iovec(dreq, iter, pos);
+	result = nfs_direct_read_schedule_iovec(dreq, iter, iocb->ki_pos);
 
 	inode_unlock(inode);
 
 	if (!result) {
 		result = nfs_direct_wait(dreq);
 		if (result > 0)
-			iocb->ki_pos = pos + result;
+			iocb->ki_pos += result;
 	}
 
 	nfs_direct_req_release(dreq);
@@ -969,7 +967,6 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
  * nfs_file_direct_write - file direct write operation for NFS files
  * @iocb: target I/O control block
  * @iter: vector of user buffers from which to write data
- * @pos: byte offset in file where writing starts
  *
  * We use this function for direct writes instead of calling
  * generic_file_aio_write() in order to avoid taking the inode
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index be01095..717a8d6 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -164,7 +164,7 @@ nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
 	ssize_t result;
 
 	if (iocb->ki_flags & IOCB_DIRECT)
-		return nfs_file_direct_read(iocb, to, iocb->ki_pos);
+		return nfs_file_direct_read(iocb, to);
 
 	dprintk("NFS: read(%pD2, %zu@%lu)\n",
 		iocb->ki_filp,
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 5346313..cfebcd2 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -305,7 +305,7 @@ static int nilfs_write_end(struct file *file, struct address_space *mapping,
 }
 
 static ssize_t
-nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
+nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct inode *inode = file_inode(iocb->ki_filp);
 
@@ -313,7 +313,7 @@ nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 		return 0;
 
 	/* Needs synchronization with the cleaner */
-	return blockdev_direct_IO(iocb, inode, iter, offset, nilfs_get_block);
+	return blockdev_direct_IO(iocb, inode, iter, nilfs_get_block);
 }
 
 const struct address_space_operations nilfs_aops = {
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index ad15773..6c66c62 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2423,13 +2423,11 @@ static int ocfs2_dio_end_io(struct kiocb *iocb,
 	return 0;
 }
 
-static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			       loff_t offset)
+static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file)->i_mapping->host;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-	loff_t end = offset + iter->count;
 	get_block_t *get_block;
 
 	/*
@@ -2440,7 +2438,8 @@ static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 		return 0;
 
 	/* Fallback to buffered I/O if we do not support append dio. */
-	if (end > i_size_read(inode) && !ocfs2_supports_append_dio(osb))
+	if (iocb->ki_pos + iter->count > i_size_read(inode) &&
+	    !ocfs2_supports_append_dio(osb))
 		return 0;
 
 	if (iov_iter_rw(iter) == READ)
@@ -2449,7 +2448,7 @@ static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 		get_block = ocfs2_dio_get_block;
 
 	return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
-				    iter, offset, get_block,
+				    iter, get_block,
 				    ocfs2_dio_end_io, NULL, 0);
 }
 
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index d5c2e9c..825455d 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -3279,15 +3279,14 @@ static int reiserfs_releasepage(struct page *page, gfp_t unused_gfp_flags)
  * We thank Mingming Cao for helping us understand in great detail what
  * to do in this section of the code.
  */
-static ssize_t reiserfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-				  loff_t offset)
+static ssize_t reiserfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(iocb, inode, iter, offset,
+	ret = blockdev_direct_IO(iocb, inode, iter,
 				 reiserfs_get_blocks_direct_io);
 
 	/*
@@ -3296,7 +3295,7 @@ static ssize_t reiserfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	 */
 	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + count;
+		loff_t end = iocb->ki_pos + count;
 
 		if ((end > isize) && inode_newsize_ok(inode, isize) == 0) {
 			truncate_setsize(inode, isize);
diff --git a/fs/udf/file.c b/fs/udf/file.c
index 877ba1c..7ab8d81 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -99,8 +99,7 @@ static int udf_adinicb_write_begin(struct file *file,
 	return 0;
 }
 
-static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-				     loff_t offset)
+static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	/* Fallback to buffered I/O. */
 	return 0;
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 2dc461e..f323aff 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -214,8 +214,7 @@ static int udf_write_begin(struct file *file, struct address_space *mapping,
 	return ret;
 }
 
-static ssize_t udf_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			     loff_t offset)
+static ssize_t udf_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -223,9 +222,9 @@ static ssize_t udf_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(iocb, inode, iter, offset, udf_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, udf_get_block);
 	if (unlikely(ret < 0 && iov_iter_rw(iter) == WRITE))
-		udf_write_failed(mapping, offset + count);
+		udf_write_failed(mapping, iocb->ki_pos + count);
 	return ret;
 }
 
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index e49b240..c535887 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1406,8 +1406,7 @@ xfs_end_io_direct_write(
 STATIC ssize_t
 xfs_vm_direct_IO(
 	struct kiocb		*iocb,
-	struct iov_iter		*iter,
-	loff_t			offset)
+	struct iov_iter		*iter)
 {
 	struct inode		*inode = iocb->ki_filp->f_mapping->host;
 	dio_iodone_t		*endio = NULL;
@@ -1420,12 +1419,12 @@ xfs_vm_direct_IO(
 	}
 
 	if (IS_DAX(inode)) {
-		return dax_do_io(iocb, inode, iter, offset,
+		return dax_do_io(iocb, inode, iter,
 				 xfs_get_blocks_direct, endio, 0);
 	}
 
 	bdev = xfs_find_bdev_for_inode(inode);
-	return  __blockdev_direct_IO(iocb, inode, bdev, iter, offset,
+	return  __blockdev_direct_IO(iocb, inode, bdev, iter,
 			xfs_get_blocks_direct, endio, NULL, flags);
 }
 
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 92f72fb..5de047a 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -794,7 +794,7 @@ xfs_file_dio_aio_write(
 	trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
 
 	data = *from;
-	ret = mapping->a_ops->direct_IO(iocb, &data, iocb->ki_pos);
+	ret = mapping->a_ops->direct_IO(iocb, &data);
 
 	/* see generic_file_direct_write() for why this is necessary */
 	if (mapping->nrpages) {
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 636dd59..982a6c4 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -5,7 +5,7 @@
 #include <linux/mm.h>
 #include <asm/pgtable.h>
 
-ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
+ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *,
 		  get_block_t, dio_iodone_t, int flags);
 int dax_clear_sectors(struct block_device *bdev, sector_t _sector, long _size);
 int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a06c7c8..dc29d12 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -394,7 +394,7 @@ struct address_space_operations {
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, gfp_t);
 	void (*freepage)(struct page *);
-	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset);
+	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 	/*
 	 * migrate the contents of a page to the specified target. If
 	 * migrate_mode is MIGRATE_ASYNC, it must not block.
@@ -2756,18 +2756,17 @@ void dio_end_io(struct bio *bio, int error);
 
 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 			     struct block_device *bdev, struct iov_iter *iter,
-			     loff_t offset, get_block_t get_block,
+			     get_block_t get_block,
 			     dio_iodone_t end_io, dio_submit_t submit_io,
 			     int flags);
 
 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
 					 struct inode *inode,
-					 struct iov_iter *iter, loff_t offset,
+					 struct iov_iter *iter,
 					 get_block_t get_block)
 {
 	return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
-				    offset, get_block, NULL, NULL,
-				    DIO_LOCKING | DIO_SKIP_HOLES);
+			get_block, NULL, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
 }
 #endif
 
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 67300f8..cede8f6 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -445,10 +445,9 @@ static inline struct rpc_cred *nfs_file_cred(struct file *file)
 /*
  * linux/fs/nfs/direct.c
  */
-extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *, loff_t);
+extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *);
 extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
-			struct iov_iter *iter,
-			loff_t pos);
+			struct iov_iter *iter);
 extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
 			struct iov_iter *iter);
 
diff --git a/mm/filemap.c b/mm/filemap.c
index e7108c3..cb36db9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1853,8 +1853,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 					iocb->ki_pos + count - 1);
 		if (!retval) {
 			struct iov_iter data = *iter;
-			retval = mapping->a_ops->direct_IO(iocb, &data,
-					iocb->ki_pos);
+			retval = mapping->a_ops->direct_IO(iocb, &data);
 		}
 
 		if (retval > 0) {
@@ -2538,7 +2537,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 	}
 
 	data = *from;
-	written = mapping->a_ops->direct_IO(iocb, &data, pos);
+	written = mapping->a_ops->direct_IO(iocb, &data);
 
 	/*
 	 * Finally, try again to invalidate clean pages which might have been
diff --git a/mm/page_io.c b/mm/page_io.c
index cd92e3d..8927560 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -279,7 +279,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
 
 		set_page_writeback(page);
 		unlock_page(page);
-		ret = mapping->a_ops->direct_IO(&kiocb, &from, kiocb.ki_pos);
+		ret = mapping->a_ops->direct_IO(&kiocb, &from);
 		if (ret == PAGE_SIZE) {
 			count_vm_event(PSWPOUT);
 			ret = 0;
-- 
2.1.4

[PATCH 05/10] direct-io: remove the offset argument to dio_complete

[Christoph Hellwig]

It has to be identical to ki_pos of the iocb, so use that instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/direct-io.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 8949d3e..c61314b 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -224,9 +224,9 @@ static inline struct page *dio_get_page(struct dio *dio,
  * filesystems can use it to hold additional state between get_block calls and
  * dio_complete.
  */
-static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret,
-		bool is_async)
+static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
 {
+	loff_t offset = dio->iocb->ki_pos;
 	ssize_t transferred = 0;
 
 	/*
@@ -285,7 +285,7 @@ static void dio_aio_complete_work(struct work_struct *work)
 {
 	struct dio *dio = container_of(work, struct dio, complete_work);
 
-	dio_complete(dio, dio->iocb->ki_pos, 0, true);
+	dio_complete(dio, 0, true);
 }
 
 static int dio_bio_complete(struct dio *dio, struct bio *bio);
@@ -314,7 +314,7 @@ static void dio_bio_end_aio(struct bio *bio)
 			queue_work(dio->inode->i_sb->s_dio_done_wq,
 				   &dio->complete_work);
 		} else {
-			dio_complete(dio, dio->iocb->ki_pos, 0, true);
+			dio_complete(dio, 0, true);
 		}
 	}
 }
@@ -1319,7 +1319,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 		dio_await_completion(dio);
 
 	if (drop_refcount(dio) == 0) {
-		retval = dio_complete(dio, offset, retval, false);
+		retval = dio_complete(dio, retval, false);
 	} else
 		BUG_ON(retval != -EIOCBQUEUED);
 
-- 
2.1.4

[PATCH 06/10] fs: add IOCB_SYNC and IOCB_DSYNC

[Christoph Hellwig]

This will allow us to do per-I/O sync file writes, as required by a lot
of fileservers or storage targets.

XXX: Will need a few additional audits for O_DSYNC
---
 fs/block_dev.c     |  2 +-
 fs/btrfs/file.c    |  2 +-
 fs/cifs/file.c     |  2 +-
 fs/direct-io.c     |  2 +-
 fs/ext4/file.c     |  2 +-
 fs/f2fs/file.c     |  2 +-
 fs/gfs2/file.c     |  5 ++++-
 fs/nfs/direct.c    |  2 +-
 fs/ntfs/file.c     |  2 +-
 fs/udf/file.c      |  2 +-
 fs/xfs/xfs_file.c  |  2 +-
 include/linux/fs.h | 14 ++++++++++----
 mm/filemap.c       |  2 +-
 13 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9e1f3fe..d8dc351 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1662,7 +1662,7 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	ret = __generic_file_write_iter(iocb, from);
 	if (ret > 0) {
 		ssize_t err;
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
 		if (err < 0)
 			ret = err;
 	}
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index d28ec60..9d8e22c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1852,7 +1852,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	BTRFS_I(inode)->last_sub_trans = root->log_transid;
 	spin_unlock(&BTRFS_I(inode)->lock);
 	if (num_written > 0) {
-		err = generic_write_sync(file, pos, num_written);
+		err = generic_write_sync(iocb, pos, num_written);
 		if (err < 0)
 			num_written = err;
 	}
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index cb070aa..b22b68c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2688,7 +2688,7 @@ out:
 	inode_unlock(inode);
 
 	if (rc > 0) {
-		ssize_t err = generic_write_sync(file, iocb->ki_pos - rc, rc);
+		ssize_t err = generic_write_sync(iocb, iocb->ki_pos - rc, rc);
 		if (err < 0)
 			rc = err;
 	}
diff --git a/fs/direct-io.c b/fs/direct-io.c
index c61314b..f7bcc01 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -268,7 +268,7 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
 		if (dio->rw & WRITE) {
 			int err;
 
-			err = generic_write_sync(dio->iocb->ki_filp, offset,
+			err = generic_write_sync(dio->iocb, offset,
 						 transferred);
 			if (err < 0 && ret > 0)
 				ret = err;
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 0caece3..5915928 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -172,7 +172,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (ret > 0) {
 		ssize_t err;
 
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
 		if (err < 0)
 			ret = err;
 	}
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 443e077..51ed838 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1885,7 +1885,7 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (ret > 0) {
 		ssize_t err;
 
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
 		if (err < 0)
 			ret = err;
 	}
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 208efc7..5a7d696 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -895,7 +895,10 @@ static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t
 		mark_inode_dirty(inode);
 	}
 
-	return generic_write_sync(file, pos, count);
+	if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
+		return vfs_fsync_range(file, pos, pos + count - 1,
+			       (file->f_flags & __O_SYNC) ? 0 : 1);
+	return 0;
 
 out_trans_fail:
 	gfs2_inplace_release(ip);
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 346b5d8..be86de9 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -1054,7 +1054,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 			if (i_size_read(inode) < iocb->ki_pos)
 				i_size_write(inode, iocb->ki_pos);
 			spin_unlock(&inode->i_lock);
-			generic_write_sync(file, pos, result);
+			generic_write_sync(iocb, pos, result);
 		}
 	}
 	nfs_direct_req_release(dreq);
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 91117ad..10dc38c 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -1953,7 +1953,7 @@ static ssize_t ntfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	current->backing_dev_info = NULL;
 	inode_unlock(vi);
 	if (likely(written > 0)) {
-		err = generic_write_sync(file, iocb->ki_pos, written);
+		err = generic_write_sync(iocb, iocb->ki_pos, written);
 		if (err < 0)
 			written = 0;
 	}
diff --git a/fs/udf/file.c b/fs/udf/file.c
index 7ab8d81..8e3d1ae 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -152,7 +152,7 @@ out:
 
 	if (retval > 0) {
 		mark_inode_dirty(inode);
-		err = generic_write_sync(file, iocb->ki_pos - retval, retval);
+		err = generic_write_sync(iocb, iocb->ki_pos - retval, retval);
 		if (err < 0)
 			retval = err;
 	}
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5de047a..b5d70e7 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -908,7 +908,7 @@ xfs_file_write_iter(
 		XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
 
 		/* Handle various SYNC-type writes */
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
 		if (err < 0)
 			ret = err;
 	}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index dc29d12..1e61161 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -323,6 +323,8 @@ struct writeback_control;
 #define IOCB_APPEND		(1 << 1)
 #define IOCB_DIRECT		(1 << 2)
 #define IOCB_HIPRI		(1 << 3)
+#define IOCB_DSYNC		(1 << 4)
+#define IOCB_SYNC		(1 << 5)
 
 struct kiocb {
 	struct file		*ki_filp;
@@ -2475,12 +2477,12 @@ extern int filemap_fdatawrite_range(struct address_space *mapping,
 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
 			   int datasync);
 extern int vfs_fsync(struct file *file, int datasync);
-static inline int generic_write_sync(struct file *file, loff_t pos, loff_t count)
+static inline int generic_write_sync(struct kiocb *iocb, loff_t pos, loff_t count)
 {
-	if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
+	if (!(iocb->ki_flags & IOCB_DSYNC))
 		return 0;
-	return vfs_fsync_range(file, pos, pos + count - 1,
-			       (file->f_flags & __O_SYNC) ? 0 : 1);
+	return vfs_fsync_range(iocb->ki_filp, pos, pos + count - 1,
+			       (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
 }
 extern void emergency_sync(void);
 extern void emergency_remount(void);
@@ -2932,6 +2934,10 @@ static inline int iocb_flags(struct file *file)
 		res |= IOCB_APPEND;
 	if (io_is_direct(file))
 		res |= IOCB_DIRECT;
+	if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
+		res |= IOCB_DSYNC;
+	if (file->f_flags & __O_SYNC)
+		res |= IOCB_SYNC;
 	return res;
 }
 
diff --git a/mm/filemap.c b/mm/filemap.c
index cb36db9..8345d6d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2794,7 +2794,7 @@ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (ret > 0) {
 		ssize_t err;
 
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
 		if (err < 0)
 			ret = err;
 	}
-- 
2.1.4

[PATCH 07/10] fs: simplify the generic_write_sync prototype

[Christoph Hellwig]

The kiocb already has the new position, so use that.  The only interesting
case is AIO, where we currently don't bother updating ki_pos.  We're about
to free the kiocb after we're done, so we might as well update it to make
everyone's life simpler.

While we're at it also return the bytes written argument passed in if
we were successful so that the boilerplate error switch code in the
callers can go away.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/block_dev.c     |  8 ++------
 fs/btrfs/file.c    |  7 ++-----
 fs/cifs/file.c     |  7 ++-----
 fs/direct-io.c     | 17 +++++++++--------
 fs/ext4/file.c     |  9 ++-------
 fs/f2fs/file.c     |  9 ++-------
 fs/nfs/direct.c    |  4 +++-
 fs/ntfs/file.c     |  7 ++-----
 fs/udf/file.c      |  4 +---
 fs/xfs/xfs_file.c  |  6 +-----
 include/linux/fs.h | 24 ++++++++++++++++++------
 mm/filemap.c       |  9 ++-------
 12 files changed, 46 insertions(+), 65 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index d8dc351..a063d4d 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1660,12 +1660,8 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 	blk_start_plug(&plug);
 	ret = __generic_file_write_iter(iocb, from);
-	if (ret > 0) {
-		ssize_t err;
-		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
 	blk_finish_plug(&plug);
 	return ret;
 }
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9d8e22c..a927c12 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1851,11 +1851,8 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	spin_lock(&BTRFS_I(inode)->lock);
 	BTRFS_I(inode)->last_sub_trans = root->log_transid;
 	spin_unlock(&BTRFS_I(inode)->lock);
-	if (num_written > 0) {
-		err = generic_write_sync(iocb, pos, num_written);
-		if (err < 0)
-			num_written = err;
-	}
+	if (num_written > 0)
+		num_written = generic_write_sync(iocb, num_written);
 
 	if (sync)
 		atomic_dec(&BTRFS_I(inode)->sync_writers);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index b22b68c..9b51d49 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2687,11 +2687,8 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 out:
 	inode_unlock(inode);
 
-	if (rc > 0) {
-		ssize_t err = generic_write_sync(iocb, iocb->ki_pos - rc, rc);
-		if (err < 0)
-			rc = err;
-	}
+	if (rc > 0)
+		rc = generic_write_sync(iocb, rc);
 	up_read(&cinode->lock_sem);
 	return rc;
 }
diff --git a/fs/direct-io.c b/fs/direct-io.c
index f7bcc01..3bf3f20 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -256,6 +256,7 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
 	if (dio->end_io) {
 		int err;
 
+		// XXX: ki_pos??
 		err = dio->end_io(dio->iocb, offset, ret, dio->private);
 		if (err)
 			ret = err;
@@ -265,15 +266,15 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
 		inode_dio_end(dio->inode);
 
 	if (is_async) {
-		if (dio->rw & WRITE) {
-			int err;
-
-			err = generic_write_sync(dio->iocb, offset,
-						 transferred);
-			if (err < 0 && ret > 0)
-				ret = err;
-		}
+		/*
+		 * generic_write_sync expects ki_pos to have been updated
+		 * already, but the submission path only does this for
+		 * synchronous I/O.
+		 */
+		dio->iocb->ki_pos += transferred;
 
+		if (dio->rw & WRITE)
+			ret = generic_write_sync(dio->iocb,  transferred);
 		dio->iocb->ki_complete(dio->iocb, ret, 0);
 	}
 
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 5915928..59f3ccc 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -169,13 +169,8 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	ret = __generic_file_write_iter(iocb, from);
 	inode_unlock(inode);
 
-	if (ret > 0) {
-		ssize_t err;
-
-		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
 	if (o_direct)
 		blk_finish_plug(&plug);
 
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 51ed838..28f75a1 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1882,13 +1882,8 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	}
 	inode_unlock(inode);
 
-	if (ret > 0) {
-		ssize_t err;
-
-		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
 	return ret;
 }
 
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index be86de9..0b9fca0 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -1054,7 +1054,9 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 			if (i_size_read(inode) < iocb->ki_pos)
 				i_size_write(inode, iocb->ki_pos);
 			spin_unlock(&inode->i_lock);
-			generic_write_sync(iocb, pos, result);
+
+			/* XXX: should check the generic_write_sync retval */
+			generic_write_sync(iocb, result);
 		}
 	}
 	nfs_direct_req_release(dreq);
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 10dc38c..5622ed5 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -1952,12 +1952,9 @@ static ssize_t ntfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		written = ntfs_perform_write(file, from, iocb->ki_pos);
 	current->backing_dev_info = NULL;
 	inode_unlock(vi);
-	if (likely(written > 0)) {
-		err = generic_write_sync(iocb, iocb->ki_pos, written);
-		if (err < 0)
-			written = 0;
-	}
 	iocb->ki_pos += written;
+	if (likely(written > 0))
+		written = generic_write_sync(iocb, written);
 	return written ? written : err;
 }
 
diff --git a/fs/udf/file.c b/fs/udf/file.c
index 8e3d1ae..6325706 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -152,9 +152,7 @@ out:
 
 	if (retval > 0) {
 		mark_inode_dirty(inode);
-		err = generic_write_sync(iocb, iocb->ki_pos - retval, retval);
-		if (err < 0)
-			retval = err;
+		retval = generic_write_sync(iocb, retval);
 	}
 
 	return retval;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index b5d70e7..cd35409 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -903,14 +903,10 @@ xfs_file_write_iter(
 		ret = xfs_file_buffered_aio_write(iocb, from);
 
 	if (ret > 0) {
-		ssize_t err;
-
 		XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
 
 		/* Handle various SYNC-type writes */
-		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
+		ret = generic_write_sync(iocb, ret);
 	}
 	return ret;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1e61161..250e426 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2477,13 +2477,25 @@ extern int filemap_fdatawrite_range(struct address_space *mapping,
 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
 			   int datasync);
 extern int vfs_fsync(struct file *file, int datasync);
-static inline int generic_write_sync(struct kiocb *iocb, loff_t pos, loff_t count)
-{
-	if (!(iocb->ki_flags & IOCB_DSYNC))
-		return 0;
-	return vfs_fsync_range(iocb->ki_filp, pos, pos + count - 1,
-			       (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
+
+/*
+ * Sync the bytes written if this was a synchronous write.  Expect ki_pos
+ * to already be updated for the write, and will return either the amount
+ * of bytes passed in, or an error if syncing the file failed.
+ */
+static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
+{
+	if (iocb->ki_flags & IOCB_DSYNC) {
+		int ret = vfs_fsync_range(iocb->ki_filp,
+				iocb->ki_pos - count, iocb->ki_pos - 1,
+				(iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
+		if (ret)
+			return ret;
+	}
+
+	return count;
 }
+
 extern void emergency_sync(void);
 extern void emergency_remount(void);
 #ifdef CONFIG_BLOCK
diff --git a/mm/filemap.c b/mm/filemap.c
index 8345d6d..182b218 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2791,13 +2791,8 @@ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		ret = __generic_file_write_iter(iocb, from);
 	inode_unlock(inode);
 
-	if (ret > 0) {
-		ssize_t err;
-
-		err = generic_write_sync(iocb, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
 	return ret;
 }
 EXPORT_SYMBOL(generic_file_write_iter);
-- 
2.1.4

[PATCH 08/10] ceph: use generic_write_sync

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/ceph/file.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index a79f926..4f1dc71 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1382,12 +1382,11 @@ retry_snap:
 	     ceph_cap_string(got));
 	ceph_put_cap_refs(ci, got);
 
-	if (written >= 0 &&
-	    ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||
-	     ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
-		err = vfs_fsync_range(file, pos, pos + written - 1, 1);
-		if (err < 0)
-			written = err;
+	if (written >= 0) {
+		if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))
+			iocb->ki_flags |= IOCB_DSYNC;
+
+		written = generic_write_sync(iocb, written);
 	}
 
 	goto out_unlocked;
-- 
2.1.4

[PATCH 09/10] fs: add RWF_DSYNC aand RWF_SYNC

[Christoph Hellwig]

This is the per-I/O equivalent of O_DSYNC and O_SYNC, and very useful for
all kinds of file servers and storage targets.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/read_write.c         | 6 +++++-
 include/uapi/linux/fs.h | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index cf377cf..3729d8d 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -698,12 +698,16 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
 	struct kiocb kiocb;
 	ssize_t ret;
 
-	if (flags & ~RWF_HIPRI)
+	if (flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC))
 		return -EOPNOTSUPP;
 
 	init_sync_kiocb(&kiocb, filp);
 	if (flags & RWF_HIPRI)
 		kiocb.ki_flags |= IOCB_HIPRI;
+	if (flags & RWF_DSYNC)
+		kiocb.ki_flags |= IOCB_DSYNC;
+	if (flags & RWF_SYNC)
+		kiocb.ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
 	kiocb.ki_pos = *ppos;
 
 	ret = fn(&kiocb, iter);
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index a079d50..e21fe04 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -324,5 +324,7 @@ struct fscrypt_policy {
 
 /* flags for preadv2/pwritev2: */
 #define RWF_HIPRI			0x00000001 /* high priority request, poll if possible */
+#define RWF_DSYNC			0x00000002 /* per-IO O_DSYNC */
+#define RWF_SYNC			0x00000004 /* per-IO O_SYNC */
 
 #endif /* _UAPI_LINUX_FS_H */
-- 
2.1.4

[PATCH 10/10] nfsd: use RWF_SYNC

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/nfsd/vfs.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index d40010e..6fbd81e 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -935,8 +935,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	int			stable = *stablep;
 	int			use_wgather;
 	loff_t			pos = offset;
-	loff_t			end = LLONG_MAX;
 	unsigned int		pflags = current->flags;
+	int			flags = 0;
 
 	if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
 		/*
@@ -955,9 +955,12 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	if (!EX_ISSYNC(exp))
 		stable = 0;
 
+	if (stable && !use_wgather)
+		flags |= RWF_SYNC;
+
 	/* Write the data. */
 	oldfs = get_fs(); set_fs(KERNEL_DS);
-	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos, 0);
+	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos, flags);
 	set_fs(oldfs);
 	if (host_err < 0)
 		goto out_nfserr;
@@ -965,15 +968,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	nfsdstats.io_write += host_err;
 	fsnotify_modify(file);
 
-	if (stable) {
-		if (use_wgather) {
-			host_err = wait_for_concurrent_writes(file);
-		} else {
-			if (*cnt)
-				end = offset + *cnt - 1;
-			host_err = vfs_fsync_range(file, offset, end, 0);
-		}
-	}
+	if (stable && use_wgather)
+		host_err = wait_for_concurrent_writes(file);
 
 out_nfserr:
 	dprintk("nfsd: write complete host_err=%d\n", host_err);
-- 
2.1.4

Re: [PATCH 03/10] xfs: eliminate the pos variable in xfs_file_dio_aio_write

[Dave Chinner]

On Thu, Apr 07, 2016 at 08:51:57AM -0700, Christoph Hellwig wrote:
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_file.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
....

Looks fine. Do you want me to pull this directly into the XFS tree?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

Re: [PATCH 03/10] xfs: eliminate the pos variable in xfs_file_dio_aio_write

[Christoph Hellwig]

On Fri, Apr 08, 2016 at 08:31:11AM +1000, Dave Chinner wrote:
> On Thu, Apr 07, 2016 at 08:51:57AM -0700, Christoph Hellwig wrote:
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > ---
> >  fs/xfs/xfs_file.c | 17 ++++++++---------
> >  1 file changed, 8 insertions(+), 9 deletions(-)
> ....
> 
> Looks fine. Do you want me to pull this directly into the XFS tree?

The following patches depend on it, so everything should really go
through Al's tree.

Re: [PATCH 03/10] xfs: eliminate the pos variable in xfs_file_dio_aio_write

[Dave Chinner]

On Fri, Apr 08, 2016 at 12:43:12AM +0200, Christoph Hellwig wrote:
> On Fri, Apr 08, 2016 at 08:31:11AM +1000, Dave Chinner wrote:
> > On Thu, Apr 07, 2016 at 08:51:57AM -0700, Christoph Hellwig wrote:
> > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > > ---
> > >  fs/xfs/xfs_file.c | 17 ++++++++---------
> > >  1 file changed, 8 insertions(+), 9 deletions(-)
> > ....
> > 
> > Looks fine. Do you want me to pull this directly into the XFS tree?
> 
> The following patches depend on it, so everything should really go
> through Al's tree.

No worries, just wanted to make sure.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

Re: add RWF_(D)SYNC flag to preadv2/pwritev2 V2

[Christoph Hellwig]

All, can you pick this up for for-next so that it gets some time
in linux-next?  Thanks!

Re: [PATCH 09/10] fs: add RWF_DSYNC aand RWF_SYNC

[Michael Kerrisk (man-pages)]

Hello Christoph,

On 8 April 2016 at 01:52, Christoph Hellwig <hch@lst.de> wrote:
> This is the per-I/O equivalent of O_DSYNC and O_SYNC, and very useful for
> all kinds of file servers and storage targets.

I've added some documentation for these flags to the man page, but in
the process I realized that have a question. Do these flags provide
equivalents of O_DSYNC and O_SYNC for the I/O operation, or for the
file? What I mean is this: with, say, RWF_DSYNC, is it just the data
written by this pwritev2() call that is synced to the underlying file,
or is all dirty data for the file synced at that point?

Thanks,

Michael


> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/read_write.c         | 6 +++++-
>  include/uapi/linux/fs.h | 2 ++
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/fs/read_write.c b/fs/read_write.c
> index cf377cf..3729d8d 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -698,12 +698,16 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
>         struct kiocb kiocb;
>         ssize_t ret;
>
> -       if (flags & ~RWF_HIPRI)
> +       if (flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC))
>                 return -EOPNOTSUPP;
>
>         init_sync_kiocb(&kiocb, filp);
>         if (flags & RWF_HIPRI)
>                 kiocb.ki_flags |= IOCB_HIPRI;
> +       if (flags & RWF_DSYNC)
> +               kiocb.ki_flags |= IOCB_DSYNC;
> +       if (flags & RWF_SYNC)
> +               kiocb.ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
>         kiocb.ki_pos = *ppos;
>
>         ret = fn(&kiocb, iter);
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index a079d50..e21fe04 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -324,5 +324,7 @@ struct fscrypt_policy {
>
>  /* flags for preadv2/pwritev2: */
>  #define RWF_HIPRI                      0x00000001 /* high priority request, poll if possible */
> +#define RWF_DSYNC                      0x00000002 /* per-IO O_DSYNC */
> +#define RWF_SYNC                       0x00000004 /* per-IO O_SYNC */
>
>  #endif /* _UAPI_LINUX_FS_H */
> --
> 2.1.4
>
> --
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-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/

Re: [PATCH 09/10] fs: add RWF_DSYNC aand RWF_SYNC

[Christoph Hellwig]

Hi Michael,

On Sun, Aug 07, 2016 at 07:45:03AM +1000, Michael Kerrisk (man-pages) wrote:
> I've added some documentation for these flags to the man page, but in
> the process I realized that have a question. Do these flags provide
> equivalents of O_DSYNC and O_SYNC for the I/O operation, or for the
> file? What I mean is this: with, say, RWF_DSYNC, is it just the data
> written by this pwritev2() call that is synced to the underlying file,
> or is all dirty data for the file synced at that point?

You beat me to it - I'm overdue sending you updates for these flags.

The flags only affect the actual pwritev2 operation they are applied
to.  That is only the range just written is guaranteed to be on
stable storage.

Btw, I was going to just send you a patch, but it seems your update
isn't out in the git tree yet, is it?

Re: [PATCH 09/10] fs: add RWF_DSYNC aand RWF_SYNC

[Michael Kerrisk (man-pages)]

Hi Christoph,

Sorry -- somehow I missed that you replied to my message...

On 08/09/2016 08:15 PM, Christoph Hellwig wrote:
> Hi Michael,
> 
> On Sun, Aug 07, 2016 at 07:45:03AM +1000, Michael Kerrisk (man-pages) wrote:
>> I've added some documentation for these flags to the man page, but in
>> the process I realized that have a question. Do these flags provide
>> equivalents of O_DSYNC and O_SYNC for the I/O operation, or for the
>> file? What I mean is this: with, say, RWF_DSYNC, is it just the data
>> written by this pwritev2() call that is synced to the underlying file,
>> or is all dirty data for the file synced at that point?
> 
> You beat me to it - I'm overdue sending you updates for these flags.
> 
> The flags only affect the actual pwritev2 operation they are applied
> to.  That is only the range just written is guaranteed to be on
> stable storage.

Thanks. I added some words to make that clear:

       RWF_DSYNC (since Linux 4.7)
              Provide a per-write equivalent of the O_DSYNC open(2) flag.
#             This flag is meaningful only for pwritev2(), and its effect
#             applies only to the data range written by the system call.

       RWF_SYNC (since Linux 4.7)
              Provide a per-write equivalent of the O_SYNC open(2)  flag.
#             This flag is meaningful only for pwritev2(), and its effect
#             applies only to the data range written by the system call.


> Btw, I was going to just send you a patch, but it seems your update
> isn't out in the git tree yet, is it?

They were sitting in a private branch while I waited for (and missed)
your reply. The changes are now pushed in master. Thanks for your help.

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/