[11/17] iomap: assign current->backing_dev_info in iomap_file_buffered_write
Commit Message
Move the assignment to current->backing_dev_info from the callers into
iomap_file_buffered_write. Note that zonefs was missing this assignment
before.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/gfs2/file.c | 3 ---
fs/iomap/buffered-io.c | 4 ++++
fs/xfs/xfs_file.c | 5 -----
3 files changed, 4 insertions(+), 8 deletions(-)
Comments
On Mon, Apr 24, 2023 at 07:49:20AM +0200, Christoph Hellwig wrote:
> Move the assignment to current->backing_dev_info from the callers into
> iomap_file_buffered_write. Note that zonefs was missing this assignment
> before.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/gfs2/file.c | 3 ---
> fs/iomap/buffered-io.c | 4 ++++
> fs/xfs/xfs_file.c | 5 -----
> 3 files changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> index 8c4fad359ff538..4d88c6080b3e30 100644
> --- a/fs/gfs2/file.c
> +++ b/fs/gfs2/file.c
> @@ -25,7 +25,6 @@
> #include <linux/dlm.h>
> #include <linux/dlm_plock.h>
> #include <linux/delay.h>
> -#include <linux/backing-dev.h>
> #include <linux/fileattr.h>
>
> #include "gfs2.h"
> @@ -1041,11 +1040,9 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
> goto out_unlock;
> }
>
> - current->backing_dev_info = inode_to_bdi(inode);
> pagefault_disable();
> ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
> pagefault_enable();
> - current->backing_dev_info = NULL;
> if (ret > 0) {
> iocb->ki_pos += ret;
> written += ret;
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 2986be63d2bea6..3d5042efda202a 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -3,6 +3,7 @@
> * Copyright (C) 2010 Red Hat, Inc.
> * Copyright (C) 2016-2019 Christoph Hellwig.
> */
> +#include <linux/backing-dev.h>
> #include <linux/module.h>
> #include <linux/compiler.h>
> #include <linux/fs.h>
> @@ -876,8 +877,11 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
> if (iocb->ki_flags & IOCB_NOWAIT)
> iter.flags |= IOMAP_NOWAIT;
>
> + current->backing_dev_info = inode_to_bdi(iter.inode);
Dumb question from me late on a Sunday night, but does the iomap_unshare
code need to set this too? Since it works by dirtying pagecache folios
without actually changing the contents?
--D
> while ((ret = iomap_iter(&iter, ops)) > 0)
> iter.processed = iomap_write_iter(&iter, i);
> + current->backing_dev_info = NULL;
> +
> if (iter.pos == iocb->ki_pos)
> return ret;
> return iter.pos - iocb->ki_pos;
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 705250f9f90a1b..f5442e689baf15 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -27,7 +27,6 @@
>
> #include <linux/dax.h>
> #include <linux/falloc.h>
> -#include <linux/backing-dev.h>
> #include <linux/mman.h>
> #include <linux/fadvise.h>
> #include <linux/mount.h>
> @@ -717,9 +716,6 @@ xfs_file_buffered_write(
> if (ret)
> goto out;
>
> - /* We can write back this queue in page reclaim */
> - current->backing_dev_info = inode_to_bdi(inode);
> -
> trace_xfs_file_buffered_write(iocb, from);
> ret = iomap_file_buffered_write(iocb, from,
> &xfs_buffered_write_iomap_ops);
> @@ -753,7 +749,6 @@ xfs_file_buffered_write(
> goto write_retry;
> }
>
> - current->backing_dev_info = NULL;
> out:
> if (iolock)
> xfs_iunlock(ip, iolock);
> --
> 2.39.2
>
On Sun, Apr 23, 2023 at 11:18:25PM -0700, Darrick J. Wong wrote:
> > @@ -876,8 +877,11 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
> > if (iocb->ki_flags & IOCB_NOWAIT)
> > iter.flags |= IOMAP_NOWAIT;
> >
> > + current->backing_dev_info = inode_to_bdi(iter.inode);
>
> Dumb question from me late on a Sunday night, but does the iomap_unshare
> code need to set this too? Since it works by dirtying pagecache folios
> without actually changing the contents?
A very good question that I have no answer for. The
current->backing_dev_info mechanism confuses the heck out of me and
appears basically undocumented.
@@ -25,7 +25,6 @@
#include <linux/dlm.h>
#include <linux/dlm_plock.h>
#include <linux/delay.h>
-#include <linux/backing-dev.h>
#include <linux/fileattr.h>
#include "gfs2.h"
@@ -1041,11 +1040,9 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
goto out_unlock;
}
- current->backing_dev_info = inode_to_bdi(inode);
pagefault_disable();
ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
pagefault_enable();
- current->backing_dev_info = NULL;
if (ret > 0) {
iocb->ki_pos += ret;
written += ret;
@@ -3,6 +3,7 @@
* Copyright (C) 2010 Red Hat, Inc.
* Copyright (C) 2016-2019 Christoph Hellwig.
*/
+#include <linux/backing-dev.h>
#include <linux/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
@@ -876,8 +877,11 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
if (iocb->ki_flags & IOCB_NOWAIT)
iter.flags |= IOMAP_NOWAIT;
+ current->backing_dev_info = inode_to_bdi(iter.inode);
while ((ret = iomap_iter(&iter, ops)) > 0)
iter.processed = iomap_write_iter(&iter, i);
+ current->backing_dev_info = NULL;
+
if (iter.pos == iocb->ki_pos)
return ret;
return iter.pos - iocb->ki_pos;
@@ -27,7 +27,6 @@
#include <linux/dax.h>
#include <linux/falloc.h>
-#include <linux/backing-dev.h>
#include <linux/mman.h>
#include <linux/fadvise.h>
#include <linux/mount.h>
@@ -717,9 +716,6 @@ xfs_file_buffered_write(
if (ret)
goto out;
- /* We can write back this queue in page reclaim */
- current->backing_dev_info = inode_to_bdi(inode);
-
trace_xfs_file_buffered_write(iocb, from);
ret = iomap_file_buffered_write(iocb, from,
&xfs_buffered_write_iomap_ops);
@@ -753,7 +749,6 @@ xfs_file_buffered_write(
goto write_retry;
}
- current->backing_dev_info = NULL;
out:
if (iolock)
xfs_iunlock(ip, iolock);