[3/5] iomap: modify ->end_io() calling convention
diff mbox series

Message ID f4abda9c0c835d9a50b644fdbec8d43269f6b0f7.1565609891.git.mbobrowski@mbobrowski.org
State New
Headers show
Series
  • ext4: direct IO via iomap infrastructure
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Commit Message

Matthew Bobrowski Aug. 12, 2019, 12:53 p.m. UTC
This patch modifies the calling convention for the iomap ->end_io()
callback. Rather than passing either dio->error or dio->size as the 'size'
argument, we instead pass both dio->error and dio->size values separately.

In the instance that an error occurred during a write, we currently cannot
determine whether any blocks have been allocated beyond the current EOF and
data has subsequently been written to these blocks within the ->end_io()
callback. As a result, we cannot judge whether we should take the truncate
failed write path. Having both dio->error and dio->size will allow us to
perform such checks within this callback.

Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
---
 fs/iomap/direct-io.c  |  9 +++------
 fs/xfs/xfs_file.c     | 17 +++++++++--------
 include/linux/iomap.h |  4 ++--
 3 files changed, 14 insertions(+), 16 deletions(-)

Comments

Christoph Hellwig Aug. 12, 2019, 5:18 p.m. UTC | #1
please add linux-xfs to the cc list for the whole series.  Besides
touching xfs itself it is also mentioned in MAINTAINERS for the iomap
code.

On Mon, Aug 12, 2019 at 10:53:11PM +1000, Matthew Bobrowski wrote:
> -	if (size <= 0)
> -		return size;
> +	if (error || !size)
> +		return error ? error : size;

This should be:

	if (error)
		return error;
	if (!size)
		return 0;

>  	if (flags & IOMAP_DIO_COW) {
> -		error = xfs_reflink_end_cow(ip, offset, size);
> -		if (error)
> +		ret = xfs_reflink_end_cow(ip, offset, size);
> +		if (ret)

I think we can just keep reusing error here.

> +typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t size,
> +				 ssize_t error, unsigned int flags);

error should be an int and not a ssize_t.
Matthew Bobrowski Aug. 13, 2019, 10:43 a.m. UTC | #2
On Mon, Aug 12, 2019 at 10:18:32AM -0700, Christoph Hellwig wrote:
> please add linux-xfs to the cc list for the whole series.  Besides
> touching xfs itself it is also mentioned in MAINTAINERS for the iomap
> code.

Firstly, thank you for the review, highly appreciated! Secondly, not a
problem, will do.

> On Mon, Aug 12, 2019 at 10:53:11PM +1000, Matthew Bobrowski wrote:
> > -	if (size <= 0)
> > -		return size;
> > +	if (error || !size)
> > +		return error ? error : size;
> 
> This should be:
> 
> 	if (error)
> 		return error;
> 	if (!size)
> 		return 0;

OK.

> >  	if (flags & IOMAP_DIO_COW) {
> > -		error = xfs_reflink_end_cow(ip, offset, size);
> > -		if (error)
> > +		ret = xfs_reflink_end_cow(ip, offset, size);
> > +		if (ret)
> 
> I think we can just keep reusing error here.

Ah yes, that will work.

> > +typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t size,
> > +				 ssize_t error, unsigned int flags);
> 
> error should be an int and not a ssize_t.

Updated.

--M

Patch
diff mbox series

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 10517cea9682..2ccf1c6460d4 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -77,13 +77,10 @@  static ssize_t iomap_dio_complete(struct iomap_dio *dio)
 	loff_t offset = iocb->ki_pos;
 	ssize_t ret;
 
-	if (dio->end_io) {
-		ret = dio->end_io(iocb,
-				dio->error ? dio->error : dio->size,
-				dio->flags);
-	} else {
+	if (dio->end_io)
+		ret = dio->end_io(iocb, dio->size, dio->error, dio->flags);
+	else
 		ret = dio->error;
-	}
 
 	if (likely(!ret)) {
 		ret = dio->size;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 28101bbc0b78..f2bc3ac4a60e 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -369,21 +369,22 @@  static int
 xfs_dio_write_end_io(
 	struct kiocb		*iocb,
 	ssize_t			size,
+	ssize_t                 error,
 	unsigned		flags)
 {
 	struct inode		*inode = file_inode(iocb->ki_filp);
 	struct xfs_inode	*ip = XFS_I(inode);
 	loff_t			offset = iocb->ki_pos;
 	unsigned int		nofs_flag;
-	int			error = 0;
+	int			ret = 0;
 
 	trace_xfs_end_io_direct_write(ip, offset, size);
 
 	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 		return -EIO;
 
-	if (size <= 0)
-		return size;
+	if (error || !size)
+		return error ? error : size;
 
 	/*
 	 * Capture amount written on completion as we can't reliably account
@@ -399,8 +400,8 @@  xfs_dio_write_end_io(
 	nofs_flag = memalloc_nofs_save();
 
 	if (flags & IOMAP_DIO_COW) {
-		error = xfs_reflink_end_cow(ip, offset, size);
-		if (error)
+		ret = xfs_reflink_end_cow(ip, offset, size);
+		if (ret)
 			goto out;
 	}
 
@@ -411,7 +412,7 @@  xfs_dio_write_end_io(
 	 * they are converted.
 	 */
 	if (flags & IOMAP_DIO_UNWRITTEN) {
-		error = xfs_iomap_write_unwritten(ip, offset, size, true);
+		ret = xfs_iomap_write_unwritten(ip, offset, size, true);
 		goto out;
 	}
 
@@ -430,14 +431,14 @@  xfs_dio_write_end_io(
 	if (offset + size > i_size_read(inode)) {
 		i_size_write(inode, offset + size);
 		spin_unlock(&ip->i_flags_lock);
-		error = xfs_setfilesize(ip, offset, size);
+		ret = xfs_setfilesize(ip, offset, size);
 	} else {
 		spin_unlock(&ip->i_flags_lock);
 	}
 
 out:
 	memalloc_nofs_restore(nofs_flag);
-	return error;
+	return ret;
 }
 
 /*
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index bc499ceae392..900284e5c06c 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -188,8 +188,8 @@  sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
  */
 #define IOMAP_DIO_UNWRITTEN	(1 << 0)	/* covers unwritten extent(s) */
 #define IOMAP_DIO_COW		(1 << 1)	/* covers COW extent(s) */
-typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
-		unsigned flags);
+typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t size,
+				 ssize_t error, unsigned int flags);
 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 		const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);