netfs: Further cleanups after struct netfs_inode wrapper introduced

Change the signature of netfs helper functions to take a struct netfs_inode
pointer rather than a struct inode pointer where appropriate, thereby
relieving the need for the network filesystem to convert its internal inode
format down to the VFS inode only for netfslib to bounce it back up.  For
type safety, it's better not to do that (and it's less typing too).

Give netfs_write_begin() an extra argument to pass in a pointer to the
netfs_inode struct rather than deriving it internally from the file
pointer.  Note that the ->write_begin() and ->write_end() ops are intended
to be replaced in the future by netfslib code that manages this without the
need to call in twice for each page.

netfs_readpage() and similar are intended to be pointed at directly by the
address_space_operations table, so must stick to the signature dictated by
the function pointers there.

Changes
=======
- Updated the kerneldoc comments and documentation [DH].

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=wgkwKyNmNdKpQkqZ6DnmUL-x9hp0YBnUGjaPFEAdxDTbw@mail.gmail.com/

12 files changed, 16 insertions, 13 deletions

diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 1b219c21d15e..6acabc2e7dc9 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -124,7 +124,7 @@ static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
 static inline struct fscache_cookie *v9fs_inode_cookie(struct v9fs_inode *v9inode)
 {
 #ifdef CONFIG_9P_FSCACHE
-	return netfs_i_cookie(&v9inode->netfs.inode);
+	return netfs_i_cookie(&v9inode->netfs);
 #else
 	return NULL;
 #endif
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 90c6c1ba03ab..c004b9a73a92 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -274,7 +274,7 @@ static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
 	 * file.  We need to do this before we get a lock on the page in case
 	 * there's more than one writer competing for the same cache block.
 	 */
-	retval = netfs_write_begin(filp, mapping, pos, len, &folio, fsdata);
+	retval = netfs_write_begin(&v9inode->netfs, filp, mapping, pos, len, &folio, fsdata);
 	if (retval < 0)
 		return retval;
 
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index e660c6348b9d..419d2f3cf2c2 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -252,7 +252,8 @@ void v9fs_free_inode(struct inode *inode)
  */
 static void v9fs_set_netfs_context(struct inode *inode)
 {
-	netfs_inode_init(inode, &v9fs_req_ops);
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	netfs_inode_init(&v9inode->netfs, &v9fs_req_ops);
 }
 
 int v9fs_init_inode(struct v9fs_session_info *v9ses,
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index 3a5bbffdf053..d7d9402ff718 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -76,7 +76,7 @@ struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
 	/* there shouldn't be an existing inode */
 	BUG_ON(!(inode->i_state & I_NEW));
 
-	netfs_inode_init(inode, NULL);
+	netfs_inode_init(&vnode->netfs, NULL);
 	inode->i_size		= 0;
 	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
 	if (root) {
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 22811e9eacf5..89630acbc2cc 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -58,7 +58,7 @@ static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *paren
  */
 static void afs_set_netfs_context(struct afs_vnode *vnode)
 {
-	netfs_inode_init(&vnode->netfs.inode, &afs_req_ops);
+	netfs_inode_init(&vnode->netfs, &afs_req_ops);
 }
 
 /*
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 984b113a9107..a6f25d9e75b5 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -670,7 +670,7 @@ struct afs_vnode {
 static inline struct fscache_cookie *afs_vnode_cache(struct afs_vnode *vnode)
 {
 #ifdef CONFIG_AFS_FSCACHE
-	return netfs_i_cookie(&vnode->netfs.inode);
+	return netfs_i_cookie(&vnode->netfs);
 #else
 	return NULL;
 #endif
diff --git a/fs/afs/write.c b/fs/afs/write.c
index f80a6096d91c..2c885b22de34 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -60,7 +60,7 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	 * file.  We need to do this before we get a lock on the page in case
 	 * there's more than one writer competing for the same cache block.
 	 */
-	ret = netfs_write_begin(file, mapping, pos, len, &folio, fsdata);
+	ret = netfs_write_begin(&vnode->netfs, file, mapping, pos, len, &folio, fsdata);
 	if (ret < 0)
 		return ret;
 
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index f5f116ed1b9e..9763e7ea8148 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1322,10 +1322,11 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
 			    struct page **pagep, void **fsdata)
 {
 	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct folio *folio = NULL;
 	int r;
 
-	r = netfs_write_begin(file, inode->i_mapping, pos, len, &folio, NULL);
+	r = netfs_write_begin(&ci->netfs, file, inode->i_mapping, pos, len, &folio, NULL);
 	if (r == 0)
 		folio_wait_fscache(folio);
 	if (r < 0) {
diff --git a/fs/ceph/cache.h b/fs/ceph/cache.h
index 26c6ae06e2f4..dc502daac49a 100644
--- a/fs/ceph/cache.h
+++ b/fs/ceph/cache.h
@@ -28,7 +28,7 @@ void ceph_fscache_invalidate(struct inode *inode, bool dio_write);
 
 static inline struct fscache_cookie *ceph_fscache_cookie(struct ceph_inode_info *ci)
 {
-	return netfs_i_cookie(&ci->netfs.inode);
+	return netfs_i_cookie(&ci->netfs);
 }
 
 static inline void ceph_fscache_resize(struct inode *inode, loff_t to)
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 650746b3ba99..56c53ab3618e 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -460,7 +460,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
 	dout("alloc_inode %p\n", &ci->netfs.inode);
 
 	/* Set parameters for the netfs library */
-	netfs_inode_init(&ci->netfs.inode, &ceph_netfs_ops);
+	netfs_inode_init(&ci->netfs, &ceph_netfs_ops);
 
 	spin_lock_init(&ci->i_ceph_lock);
 
diff --git a/fs/cifs/fscache.h b/fs/cifs/fscache.h
index ab9a51d0125c..aa3b941a5555 100644
--- a/fs/cifs/fscache.h
+++ b/fs/cifs/fscache.h
@@ -61,7 +61,7 @@ void cifs_fscache_fill_coherency(struct inode *inode,
 
 static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode)
 {
-	return netfs_i_cookie(inode);
+	return netfs_i_cookie(&CIFS_I(inode)->netfs);
 }
 
 static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags)
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index d37e012386f3..42f892c5712e 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -297,6 +297,7 @@ zero_out:
 
 /**
  * netfs_write_begin - Helper to prepare for writing
+ * @ctx: The netfs context
  * @file: The file to read from
  * @mapping: The mapping to read from
  * @pos: File position at which the write will begin
@@ -326,12 +327,12 @@ zero_out:
  *
  * This is usable whether or not caching is enabled.
  */
-int netfs_write_begin(struct file *file, struct address_space *mapping,
+int netfs_write_begin(struct netfs_inode *ctx,
+		      struct file *file, struct address_space *mapping,
 		      loff_t pos, unsigned int len, struct folio **_folio,
 		      void **_fsdata)
 {
 	struct netfs_io_request *rreq;
-	struct netfs_inode *ctx = netfs_inode(file_inode(file ));
 	struct folio *folio;
 	unsigned int fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;
 	pgoff_t index = pos >> PAGE_SHIFT;