1 files changed, 92 insertions, 39 deletions

diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index 2a37af880978..e1706e736c64 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -34,6 +34,58 @@ struct nfs_fscache_inode_auxdata {
 	u64	change_attr;
 };
 
+struct nfs_netfs_io_data {
+	/*
+	 * NFS may split a netfs_io_subrequest into multiple RPCs, each
+	 * with their own read completion.  In netfs, we can only call
+	 * netfs_subreq_terminated() once for each subrequest.  Use the
+	 * refcount here to double as a marker of the last RPC completion,
+	 * and only call netfs via netfs_subreq_terminated() once.
+	 */
+	refcount_t			refcount;
+	struct netfs_io_subrequest	*sreq;
+
+	/*
+	 * Final disposition of the netfs_io_subrequest, sent in
+	 * netfs_subreq_terminated()
+	 */
+	atomic64_t	transferred;
+	int		error;
+};
+
+static inline void nfs_netfs_get(struct nfs_netfs_io_data *netfs)
+{
+	refcount_inc(&netfs->refcount);
+}
+
+static inline void nfs_netfs_put(struct nfs_netfs_io_data *netfs)
+{
+	ssize_t final_len;
+
+	/* Only the last RPC completion should call netfs_subreq_terminated() */
+	if (!refcount_dec_and_test(&netfs->refcount))
+		return;
+
+	/*
+	 * The NFS pageio interface may read a complete page, even when netfs
+	 * only asked for a partial page.  Specifically, this may be seen when
+	 * one thread is truncating a file while another one is reading the last
+	 * page of the file.
+	 * Correct the final length here to be no larger than the netfs subrequest
+	 * length, and thus avoid netfs's "Subreq overread" warning message.
+	 */
+	final_len = min_t(s64, netfs->sreq->len, atomic64_read(&netfs->transferred));
+	netfs_subreq_terminated(netfs->sreq, netfs->error ?: final_len, false);
+	kfree(netfs);
+}
+static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi)
+{
+	netfs_inode_init(&nfsi->netfs, &nfs_netfs_ops);
+}
+extern void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr);
+extern void nfs_netfs_read_completion(struct nfs_pgio_header *hdr);
+extern int nfs_netfs_folio_unlock(struct folio *folio);
+
 /*
  * fscache.c
  */
@@ -44,9 +96,8 @@ extern void nfs_fscache_init_inode(struct inode *);
 extern void nfs_fscache_clear_inode(struct inode *);
 extern void nfs_fscache_open_file(struct inode *, struct file *);
 extern void nfs_fscache_release_file(struct inode *, struct file *);
-
-extern int __nfs_fscache_read_page(struct inode *, struct page *);
-extern void __nfs_fscache_write_page(struct inode *, struct page *);
+extern int nfs_netfs_readahead(struct readahead_control *ractl);
+extern int nfs_netfs_read_folio(struct file *file, struct folio *folio);
 
 static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
 {
@@ -54,34 +105,11 @@ static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
 		if (current_is_kswapd() || !(gfp & __GFP_FS))
 			return false;
 		folio_wait_fscache(folio);
-		fscache_note_page_release(nfs_i_fscache(folio->mapping->host));
-		nfs_inc_fscache_stats(folio->mapping->host,
-				      NFSIOS_FSCACHE_PAGES_UNCACHED);
 	}
+	fscache_note_page_release(netfs_i_cookie(netfs_inode(folio->mapping->host)));
 	return true;
 }
 
-/*
- * Retrieve a page from an inode data storage object.
- */
-static inline int nfs_fscache_read_page(struct inode *inode, struct page *page)
-{
-	if (nfs_i_fscache(inode))
-		return __nfs_fscache_read_page(inode, page);
-	return -ENOBUFS;
-}
-
-/*
- * Store a page newly fetched from the server in an inode data storage object
- * in the cache.
- */
-static inline void nfs_fscache_write_page(struct inode *inode,
-					   struct page *page)
-{
-	if (nfs_i_fscache(inode))
-		__nfs_fscache_write_page(inode, page);
-}
-
 static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata,
 					      struct inode *inode)
 {
@@ -101,13 +129,10 @@ static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *
 static inline void nfs_fscache_invalidate(struct inode *inode, int flags)
 {
 	struct nfs_fscache_inode_auxdata auxdata;
-	struct nfs_inode *nfsi = NFS_I(inode);
+	struct fscache_cookie *cookie =  netfs_i_cookie(&NFS_I(inode)->netfs);
 
-	if (nfsi->fscache) {
-		nfs_fscache_update_auxdata(&auxdata, inode);
-		fscache_invalidate(nfsi->fscache, &auxdata,
-				   i_size_read(inode), flags);
-	}
+	nfs_fscache_update_auxdata(&auxdata, inode);
+	fscache_invalidate(cookie, &auxdata, i_size_read(inode), flags);
 }
 
 /*
@@ -120,7 +145,28 @@ static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 	return "no ";
 }
 
+static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr,
+					     struct nfs_pageio_descriptor *desc)
+{
+	hdr->netfs = desc->pg_netfs;
+}
+static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc,
+						   struct nfs_pgio_header *hdr)
+{
+	desc->pg_netfs = hdr->netfs;
+}
+static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc)
+{
+	desc->pg_netfs = NULL;
+}
 #else /* CONFIG_NFS_FSCACHE */
+static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) {}
+static inline void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr) {}
+static inline void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) {}
+static inline int nfs_netfs_folio_unlock(struct folio *folio)
+{
+	return 1;
+}
 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 
 static inline void nfs_fscache_init_inode(struct inode *inode) {}
@@ -128,22 +174,29 @@ static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 static inline void nfs_fscache_open_file(struct inode *inode,
 					 struct file *filp) {}
 static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {}
-
-static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
+static inline int nfs_netfs_readahead(struct readahead_control *ractl)
 {
-	return true; /* may release folio */
+	return -ENOBUFS;
 }
-static inline int nfs_fscache_read_page(struct inode *inode, struct page *page)
+static inline int nfs_netfs_read_folio(struct file *file, struct folio *folio)
 {
 	return -ENOBUFS;
 }
-static inline void nfs_fscache_write_page(struct inode *inode, struct page *page) {}
+
+static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
+{
+	return true; /* may release folio */
+}
 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {}
 
 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 {
 	return "no ";
 }
-
+static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr,
+					     struct nfs_pageio_descriptor *desc) {}
+static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc,
+						   struct nfs_pgio_header *hdr) {}
+static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) {}
 #endif /* CONFIG_NFS_FSCACHE */
 #endif /* _NFS_FSCACHE_H */