[PATCH 05/19] netfs: Refactor arguments for netfs_alloc_read_request

[David Howells]

From: Jeff Layton <jlayton@xxxxxxxxxx>

Pass start and len to the rreq allocator. This should ensure that the
fields are set so that init_rreq can use them.

Also add a parameter to indicates the origin of the request.  Ceph can use
this to tell whether to get caps.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: linux-cachefs@xxxxxxxxxx
---

 fs/netfs/read_helper.c |   25 ++++++++++++++++---------
 include/linux/netfs.h  |    7 +++++++
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index a90b3fbcb93f..37125ed95d1a 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -36,8 +36,11 @@ static void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
 		__netfs_put_subrequest(subreq, was_async);
 }
 
-static struct netfs_io_request *netfs_alloc_read_request(struct address_space *mapping,
-							   struct file *file)
+static struct netfs_io_request *netfs_alloc_read_request(
+	struct address_space *mapping,
+	struct file *file,
+	loff_t start, size_t len,
+	enum netfs_read_origin origin)
 {
 	static atomic_t debug_ids;
 	struct inode *inode = file ? file_inode(file) : mapping->host;
@@ -46,8 +49,11 @@ static struct netfs_io_request *netfs_alloc_read_request(struct address_space *m
 
 	rreq = kzalloc(sizeof(struct netfs_io_request), GFP_KERNEL);
 	if (rreq) {
+		rreq->start	= start;
+		rreq->len	= len;
 		rreq->mapping	= mapping;
 		rreq->inode	= inode;
+		rreq->origin	= origin;
 		rreq->netfs_ops	= ctx->ops;
 		rreq->i_size	= i_size_read(inode);
 		rreq->debug_id	= atomic_inc_return(&debug_ids);
@@ -874,11 +880,12 @@ void netfs_readahead(struct readahead_control *ractl)
 	if (readahead_count(ractl) == 0)
 		return;
 
-	rreq = netfs_alloc_read_request(ractl->mapping, ractl->file);
+	rreq = netfs_alloc_read_request(ractl->mapping, ractl->file,
+					readahead_pos(ractl),
+					readahead_length(ractl),
+					NETFS_READAHEAD);
 	if (!rreq)
 		return;
-	rreq->start	= readahead_pos(ractl);
-	rreq->len	= readahead_length(ractl);
 
 	if (ctx->ops->begin_cache_operation) {
 		ret = ctx->ops->begin_cache_operation(rreq);
@@ -941,11 +948,10 @@ int netfs_readpage(struct file *file, struct page *subpage)
 
 	_enter("%lx", folio_index(folio));
 
-	rreq = netfs_alloc_read_request(mapping, file);
+	rreq = netfs_alloc_read_request(mapping, file, folio_file_pos(folio),
+					folio_size(folio), NETFS_READPAGE);
 	if (!rreq)
 		goto nomem;
-	rreq->start	= folio_file_pos(folio);
-	rreq->len	= folio_size(folio);
 
 	if (ctx->ops->begin_cache_operation) {
 		ret = ctx->ops->begin_cache_operation(rreq);
@@ -1118,7 +1124,8 @@ int netfs_write_begin(struct file *file, struct address_space *mapping,
 	}
 
 	ret = -ENOMEM;
-	rreq = netfs_alloc_read_request(mapping, file);
+	rreq = netfs_alloc_read_request(mapping, file, folio_file_pos(folio),
+					folio_size(folio), NETFS_READ_FOR_WRITE);
 	if (!rreq)
 		goto error;
 	rreq->start		= folio_file_pos(folio);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 630b0400e9fa..a5434bc80e1c 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -158,6 +158,12 @@ struct netfs_io_subrequest {
 #define NETFS_SREQ_NO_PROGRESS		4	/* Set if we didn't manage to read any data */
 };
 
+enum netfs_read_origin {
+	NETFS_READAHEAD,		/* This read was triggered by readahead */
+	NETFS_READPAGE,			/* This read is a synchronous read */
+	NETFS_READ_FOR_WRITE,		/* This read is to prepare a write */
+} __mode(byte);
+
 /*
  * Descriptor for a read helper request.  This is used to make multiple I/O
  * requests on a variety of sources and then stitch the result together.
@@ -175,6 +181,7 @@ struct netfs_io_request {
 	size_t			submitted;	/* Amount submitted for I/O so far */
 	size_t			len;		/* Length of the request */
 	short			error;		/* 0 or error that occurred */
+	enum netfs_read_origin	origin;		/* Origin of the read */
 	loff_t			i_size;		/* Size of the file */
 	loff_t			start;		/* Start position */
 	pgoff_t			no_unlock_folio; /* Don't unlock this folio after read */