[PATCH v17 10/17] netfs: Pass the write length to request creation where appropriate

[David Howells <dhowells@redhat.com>]

For unbuffered/DIO writes and writes to single-type objects, pass the
length down into the request creation function so that wreq->len gets set
correctly.  For buffered writeback and pgpriv2 copying, this remains 0 as
we don't know in advance how big the request will be.

A subsequent patch will use this to set as the i_size on single-type
objects (e.g. afs directories) as we don't care what the old i_size was and
we don't want to see inode->i_size in the netfs file changing due to
third-party invalidation before we update fscache to say how big the object
is going to be.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@infradead.org>
cc: linux-block@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
---
 fs/netfs/direct_write.c | 4 ++--
 fs/netfs/internal.h     | 2 +-
 fs/netfs/read_pgpriv2.c | 2 +-
 fs/netfs/write_issue.c  | 9 +++++----
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c
index cc46b7d9321f..ff1795e1f0cb 100644
--- a/fs/netfs/direct_write.c
+++ b/fs/netfs/direct_write.c
@@ -222,7 +222,7 @@ static void netfs_unbuffered_write_async(struct work_struct *work)
  * encrypted file.  This can also be used for direct I/O writes.
  */
 ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter,
-						  struct netfs_group *netfs_group)
+					   struct netfs_group *netfs_group)
 {
 	struct netfs_io_request *wreq;
 	ssize_t ret, n;
@@ -241,7 +241,7 @@ ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *
 
 	_debug("uw %llx-%llx", start, end);
 
-	wreq = netfs_create_write_req(iocb->ki_filp->f_mapping, iocb->ki_filp, start,
+	wreq = netfs_create_write_req(iocb->ki_filp->f_mapping, iocb->ki_filp, start, len,
 				      iocb->ki_flags & IOCB_DIRECT ?
 				      NETFS_DIO_WRITE : NETFS_UNBUFFERED_WRITE);
 	if (IS_ERR(wreq))
diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h
index d554468bf694..6e30112c9112 100644
--- a/fs/netfs/internal.h
+++ b/fs/netfs/internal.h
@@ -238,7 +238,7 @@ void netfs_write_collection_worker(struct work_struct *work);
  */
 struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
 						struct file *file,
-						uoff_t start,
+						uoff_t start, size_t len,
 						enum netfs_io_origin origin);
 void netfs_prepare_write(struct netfs_io_request *wreq,
 			 struct netfs_io_stream *stream,
diff --git a/fs/netfs/read_pgpriv2.c b/fs/netfs/read_pgpriv2.c
index 5280b606fda4..85084aad9e31 100644
--- a/fs/netfs/read_pgpriv2.c
+++ b/fs/netfs/read_pgpriv2.c
@@ -103,7 +103,7 @@ static struct netfs_io_request *netfs_pgpriv2_begin_copy_to_cache(
 	if (!fscache_resources_valid(&rreq->cache_resources))
 		goto cancel;
 
-	creq = netfs_create_write_req(rreq->mapping, NULL, folio_pos(folio),
+	creq = netfs_create_write_req(rreq->mapping, NULL, folio_pos(folio), 0,
 				      NETFS_PGPRIV2_COPY_TO_CACHE);
 	if (IS_ERR(creq))
 		goto cancel;
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index f084a6796667..4c1e597a6d03 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -89,7 +89,7 @@ static void netfs_kill_dirty_pages(struct address_space *mapping,
  */
 struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
 						struct file *file,
-						uoff_t start,
+						uoff_t start, size_t len,
 						enum netfs_io_origin origin)
 {
 	struct netfs_io_request *wreq;
@@ -98,7 +98,7 @@ struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
 			     origin == NETFS_WRITEBACK_SINGLE ||
 			     origin == NETFS_PGPRIV2_COPY_TO_CACHE);
 
-	wreq = netfs_alloc_request(mapping, file, start, 0, origin);
+	wreq = netfs_alloc_request(mapping, file, start, len, origin);
 	if (IS_ERR(wreq))
 		return wreq;
 
@@ -573,7 +573,8 @@ int netfs_writepages(struct address_space *mapping,
 	if (!folio)
 		goto out;
 
-	wreq = netfs_create_write_req(mapping, NULL, folio_pos(folio), NETFS_WRITEBACK);
+	wreq = netfs_create_write_req(mapping, NULL, folio_pos(folio), 0,
+				      NETFS_WRITEBACK);
 	if (IS_ERR(wreq)) {
 		error = PTR_ERR(wreq);
 		goto couldnt_start;
@@ -659,7 +660,7 @@ int netfs_writeback_single(struct address_space *mapping,
 		return 1;
 	}
 
-	wreq = netfs_create_write_req(mapping, NULL, 0, NETFS_WRITEBACK_SINGLE);
+	wreq = netfs_create_write_req(mapping, NULL, 0, len, NETFS_WRITEBACK_SINGLE);
 	if (IS_ERR(wreq)) {
 		ret = PTR_ERR(wreq);
 		goto couldnt_start;