diff mbox series

[RFC,02/12] netfs: Add an iov_iter to the read subreq for the network fs/cache to use

Message ID 162687509306.276387.7579641363406546284.stgit@warthog.procyon.org.uk (mailing list archive)
State New
Headers show
Series [RFC,01/12] afs: Sort out symlink reading | expand

Commit Message

David Howells July 21, 2021, 1:44 p.m. UTC
Add an iov_iter to the read subrequest and set it up to define the
destination buffer to write into.  This will allow future patches to point
to a bounce buffer instead for purposes of handling oversize writes,
decryption (where we want to save the encrypted data to the cache) and
decompression.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/afs/file.c          |    6 +-----
 fs/netfs/read_helper.c |    5 ++++-
 include/linux/netfs.h  |    2 ++
 3 files changed, 7 insertions(+), 6 deletions(-)

Comments

Jeff Layton July 21, 2021, 5:16 p.m. UTC | #1
On Wed, 2021-07-21 at 14:44 +0100, David Howells wrote:
> Add an iov_iter to the read subrequest and set it up to define the
> destination buffer to write into.  This will allow future patches to point
> to a bounce buffer instead for purposes of handling oversize writes,
> decryption (where we want to save the encrypted data to the cache) and
> decompression.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
> 
>  fs/afs/file.c          |    6 +-----
>  fs/netfs/read_helper.c |    5 ++++-
>  include/linux/netfs.h  |    2 ++
>  3 files changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/afs/file.c b/fs/afs/file.c
> index c9c21ad0e7c9..ca529f23515a 100644
> --- a/fs/afs/file.c
> +++ b/fs/afs/file.c
> @@ -319,11 +319,7 @@ static void afs_req_issue_op(struct netfs_read_subrequest *subreq)
>  	fsreq->len	= subreq->len   - subreq->transferred;
>  	fsreq->key	= subreq->rreq->netfs_priv;
>  	fsreq->vnode	= vnode;
> -	fsreq->iter	= &fsreq->def_iter;
> -
> -	iov_iter_xarray(&fsreq->def_iter, READ,
> -			&fsreq->vnode->vfs_inode.i_mapping->i_pages,
> -			fsreq->pos, fsreq->len);
> +	fsreq->iter	= &subreq->iter;
>  
>  	afs_fetch_data(fsreq->vnode, fsreq);
>  }
> diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
> index 0b6cd3b8734c..715f3e9c380d 100644
> --- a/fs/netfs/read_helper.c
> +++ b/fs/netfs/read_helper.c
> @@ -150,7 +150,7 @@ static void netfs_clear_unread(struct netfs_read_subrequest *subreq)
>  {
>  	struct iov_iter iter;
>  
> -	iov_iter_xarray(&iter, WRITE, &subreq->rreq->mapping->i_pages,
> +	iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,

What's up with the WRITE -> READ change here? Was that a preexisting
bug?

>  			subreq->start + subreq->transferred,
>  			subreq->len   - subreq->transferred);
>  	iov_iter_zero(iov_iter_count(&iter), &iter);
> @@ -745,6 +745,9 @@ netfs_rreq_prepare_read(struct netfs_read_request *rreq,
>  	if (WARN_ON(subreq->len == 0))
>  		source = NETFS_INVALID_READ;
>  
> +	iov_iter_xarray(&subreq->iter, READ, &rreq->mapping->i_pages,
> +			subreq->start, subreq->len);
> +
>  out:
>  	subreq->source = source;
>  	trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
> diff --git a/include/linux/netfs.h b/include/linux/netfs.h
> index fe9887768292..5e4fafcc9480 100644
> --- a/include/linux/netfs.h
> +++ b/include/linux/netfs.h
> @@ -17,6 +17,7 @@
>  #include <linux/workqueue.h>
>  #include <linux/fs.h>
>  #include <linux/pagemap.h>
> +#include <linux/uio.h>
>  
>  /*
>   * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
> @@ -112,6 +113,7 @@ struct netfs_cache_resources {
>  struct netfs_read_subrequest {
>  	struct netfs_read_request *rreq;	/* Supervising read request */
>  	struct list_head	rreq_link;	/* Link in rreq->subrequests */
> +	struct iov_iter		iter;		/* Iterator for this subrequest */
>  	loff_t			start;		/* Where to start the I/O */
>  	size_t			len;		/* Size of the I/O */
>  	size_t			transferred;	/* Amount of data transferred */
> 
>
David Howells July 21, 2021, 5:20 p.m. UTC | #2
Jeff Layton <jlayton@redhat.com> wrote:

> > -	iov_iter_xarray(&iter, WRITE, &subreq->rreq->mapping->i_pages,
> > +	iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,
> 
> What's up with the WRITE -> READ change here? Was that a preexisting
> bug?

Actually, yes - I need to split that out and send it to Linus.

David
diff mbox series

Patch

diff --git a/fs/afs/file.c b/fs/afs/file.c
index c9c21ad0e7c9..ca529f23515a 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -319,11 +319,7 @@  static void afs_req_issue_op(struct netfs_read_subrequest *subreq)
 	fsreq->len	= subreq->len   - subreq->transferred;
 	fsreq->key	= subreq->rreq->netfs_priv;
 	fsreq->vnode	= vnode;
-	fsreq->iter	= &fsreq->def_iter;
-
-	iov_iter_xarray(&fsreq->def_iter, READ,
-			&fsreq->vnode->vfs_inode.i_mapping->i_pages,
-			fsreq->pos, fsreq->len);
+	fsreq->iter	= &subreq->iter;
 
 	afs_fetch_data(fsreq->vnode, fsreq);
 }
diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index 0b6cd3b8734c..715f3e9c380d 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -150,7 +150,7 @@  static void netfs_clear_unread(struct netfs_read_subrequest *subreq)
 {
 	struct iov_iter iter;
 
-	iov_iter_xarray(&iter, WRITE, &subreq->rreq->mapping->i_pages,
+	iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,
 			subreq->start + subreq->transferred,
 			subreq->len   - subreq->transferred);
 	iov_iter_zero(iov_iter_count(&iter), &iter);
@@ -745,6 +745,9 @@  netfs_rreq_prepare_read(struct netfs_read_request *rreq,
 	if (WARN_ON(subreq->len == 0))
 		source = NETFS_INVALID_READ;
 
+	iov_iter_xarray(&subreq->iter, READ, &rreq->mapping->i_pages,
+			subreq->start, subreq->len);
+
 out:
 	subreq->source = source;
 	trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index fe9887768292..5e4fafcc9480 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -17,6 +17,7 @@ 
 #include <linux/workqueue.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>
+#include <linux/uio.h>
 
 /*
  * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
@@ -112,6 +113,7 @@  struct netfs_cache_resources {
 struct netfs_read_subrequest {
 	struct netfs_read_request *rreq;	/* Supervising read request */
 	struct list_head	rreq_link;	/* Link in rreq->subrequests */
+	struct iov_iter		iter;		/* Iterator for this subrequest */
 	loff_t			start;		/* Where to start the I/O */
 	size_t			len;		/* Size of the I/O */
 	size_t			transferred;	/* Amount of data transferred */