[RFC PATCH 02/12] netfs: Add an iov_iter to the read subreq for the network fs/cache to use
From: David Howells <dhowells@redhat.com>
Date: 2021-07-21 13:45:56
Also in:
ceph-devel, linux-cifs, linux-fsdevel, linux-nfs, lkml
Subsystem:
afs filesystem, filesystems (vfs and infrastructure), filesystems [netfs library], the rest · Maintainers:
David Howells, Marc Dionne, Alexander Viro, Christian Brauner, Paulo Alcantara, Linus Torvalds
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, 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 */