[PATCH 2/6] iomap: move DIO NOWAIT setup up into filesystems

Dave Chinner
2021-01-12T01:08:54Z

From: Dave Chinner <dchinner@redhat.com>

Add a parameter to iomap_dio_rw_args to allow callers to specify
whether nonblocking (NOWAIT) submission semantics should be used by
the DIO. This allows filesystems to add their own non-blocking
contraints to DIO on top of the user specified constraints held in
the iocb.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/btrfs/file.c | 4 +++-
fs/ext4/file.c | 5 +++--
fs/gfs2/file.c | 2 ++
fs/iomap/direct-io.c | 2 +-
fs/xfs/xfs_file.c | 2 ++
fs/zonefs/super.c | 7 ++++---
include/linux/iomap.h | 3 +++
7 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a49d9fa918d1..2e7c3b7b70fe 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1913,9 +1913,10 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
.ops = &btrfs_dio_iomap_ops,
.dops = &btrfs_dio_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

- if (iocb->ki_flags & IOCB_NOWAIT)
+ if (args.nonblocking)
ilock_flags |= BTRFS_ILOCK_TRY;

/* If the write DIO is within EOF, use a shared lock */
@@ -3628,6 +3629,7 @@ static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
.ops = &btrfs_dio_iomap_ops,
.dops = &btrfs_dio_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 436508be6d88..0ce5c4cae172 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -472,6 +472,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
.ops = &ext4_iomap_ops,
.dops = &ext4_dio_write_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

/*
@@ -490,7 +491,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (offset + count > i_size_read(inode))
ilock_shared = false;

- if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (args.nonblocking) {
if (ilock_shared) {
if (!inode_trylock_shared(inode))
return -EAGAIN;
@@ -519,7 +520,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
return ret;

/* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
- if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
+ if (args.nonblocking && (unaligned_io || extend)) {
ret = -EAGAIN;
goto out;
}
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index d44a5f9c5f34..ead246202144 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -793,6 +793,7 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
.iter = to,
.ops = &gfs2_iomap_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

if (!count)
@@ -824,6 +825,7 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
.iter = from,
.ops = &gfs2_iomap_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

/*
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 05cacc27578c..c0dd2db1253b 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -478,7 +478,7 @@ __iomap_dio_rw(struct iomap_dio_rw_args *args)
dio->flags |= IOMAP_DIO_WRITE_FUA;
}

- if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (args->nonblocking) {
if (filemap_range_has_page(mapping, pos, end)) {
ret = -EAGAIN;
goto out_free_dio;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 29f4204e551f..3ced2746db4d 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -210,6 +210,7 @@ xfs_file_dio_aio_read(
.iter = to,
.ops = &xfs_read_iomap_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

trace_xfs_file_direct_read(ip, count, iocb->ki_pos);
@@ -530,6 +531,7 @@ xfs_file_dio_aio_write(
.ops = &xfs_direct_write_iomap_ops,
.dops = &xfs_dio_write_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

/* DIO must be aligned to device logical sector size */
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index edf353ad1edc..486ff4872077 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -741,6 +741,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
.ops = &zonefs_iomap_ops,
.dops = &zonefs_write_dio_ops,
.wait_for_completion = sync,
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};

/*
@@ -748,11 +749,10 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
* as this can cause write reordering (e.g. the first aio gets EAGAIN
* on the inode lock but the second goes through but is now unaligned).
*/
- if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !sync &&
- (iocb->ki_flags & IOCB_NOWAIT))
+ if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !sync && args.nonblocking)
return -EOPNOTSUPP;

- if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (args.nonblocking) {
if (!inode_trylock(inode))
return -EAGAIN;
} else {
@@ -922,6 +922,7 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
.ops = &zonefs_iomap_ops,
.dops = &zonefs_read_dio_ops,
.wait_for_completion = is_sync_kiocb(iocb),
+ .nonblocking = (iocb->ki_flags & IOCB_NOWAIT),
};
size_t count = iov_iter_count(to);

diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 16d20c01b5bb..3f85fc33a4c9 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -261,7 +261,10 @@ struct iomap_dio_rw_args {
struct iov_iter *iter;
const struct iomap_ops *ops;
const struct iomap_dio_ops *dops;
+ /* wait for completion of submitted IO if true */
bool wait_for_completion;
+ /* use non-blocking IO submission semantics if true */
+ bool nonblocking;
};

ssize_t iomap_dio_rw(struct iomap_dio_rw_args *args);
--
2.28.0