NFS: Read pages from FS-Cache into an NFS inode

Read pages from an FS-Cache data storage object representing an inode into an
NFS inode.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index e29613a8cbd2..099349c171ca 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -86,6 +86,12 @@ extern void nfs_fscache_reset_inode_cookie(struct inode *);
 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
 extern int nfs_fscache_release_page(struct page *, gfp_t);
 
+extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
+                                       struct inode *, struct page *);
+extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
+                                        struct inode *, struct address_space *,
+                                        struct list_head *, unsigned *);
+
 /*
  * wait for a page to complete writing to the cache
  */
@@ -107,6 +113,32 @@ static inline void nfs_fscache_invalidate_page(struct page *page,
                 __nfs_fscache_invalidate_page(page, inode);
 }
 
+/*
+ * Retrieve a page from an inode data storage object.
+ */
+static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
+                                            struct inode *inode,
+                                            struct page *page)
+{
+        if (NFS_I(inode)->fscache)
+                return __nfs_readpage_from_fscache(ctx, inode, page);
+        return -ENOBUFS;
+}
+
+/*
+ * Retrieve a set of pages from an inode data storage object.
+ */
+static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
+                                             struct inode *inode,
+                                             struct address_space *mapping,
+                                             struct list_head *pages,
+                                             unsigned *nr_pages)
+{
+        if (NFS_I(inode)->fscache)
+                return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
+                                                    nr_pages);
+        return -ENOBUFS;
+}
 
 #else /* CONFIG_NFS_FSCACHE */
 static inline int nfs_fscache_register(void) { return 0; }
@@ -138,5 +170,20 @@ static inline void nfs_fscache_invalidate_page(struct page *page,
 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
                                                   struct page *page) {}
 
+static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
+                                            struct inode *inode,
+                                            struct page *page)
+{
+        return -ENOBUFS;
+}
+static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
+                                             struct inode *inode,
+                                             struct address_space *mapping,
+                                             struct list_head *pages,
+                                             unsigned *nr_pages)
+{
+        return -ENOBUFS;
+}
+
 #endif /* CONFIG_NFS_FSCACHE */
 #endif /* _NFS_FSCACHE_H */