cifs: enable fscache usage even for files opened as rw

So far, the fscache implementation we had supports only
a small set of use cases. Particularly for files opened
with O_RDONLY.

This commit enables it even for rw based file opens. It
also enables the reuse of cached data in case of mount
option (cache=singleclient) where it is guaranteed that
this is the only client (and server) which operates on
the files. There's also a single line change in fscache.c
to get around a bug seen in fscache.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 33 insertions, 8 deletions

diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c
index dd625033cd6b..fab47fa7df74 100644
--- a/fs/cifs/fscache.c
+++ b/fs/cifs/fscache.c
@@ -176,29 +176,34 @@ void cifs_fscache_release_inode_cookie(struct inode *inode)
 		auxdata.last_change_time_nsec = cifsi->vfs_inode.i_ctime.tv_nsec;
 
 		cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cifsi->fscache);
+		/* fscache_relinquish_cookie does not seem to update auxdata */
+		fscache_update_cookie(cifsi->fscache, &auxdata);
 		fscache_relinquish_cookie(cifsi->fscache, &auxdata, false);
 		cifsi->fscache = NULL;
 	}
 }
 
-static void cifs_fscache_disable_inode_cookie(struct inode *inode)
+void cifs_fscache_update_inode_cookie(struct inode *inode)
 {
+	struct cifs_fscache_inode_auxdata auxdata;
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 
 	if (cifsi->fscache) {
+		memset(&auxdata, 0, sizeof(auxdata));
+		auxdata.eof = cifsi->server_eof;
+		auxdata.last_write_time_sec = cifsi->vfs_inode.i_mtime.tv_sec;
+		auxdata.last_change_time_sec = cifsi->vfs_inode.i_ctime.tv_sec;
+		auxdata.last_write_time_nsec = cifsi->vfs_inode.i_mtime.tv_nsec;
+		auxdata.last_change_time_nsec = cifsi->vfs_inode.i_ctime.tv_nsec;
+
 		cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cifsi->fscache);
-		fscache_uncache_all_inode_pages(cifsi->fscache, inode);
-		fscache_relinquish_cookie(cifsi->fscache, NULL, true);
-		cifsi->fscache = NULL;
+		fscache_update_cookie(cifsi->fscache, &auxdata);
 	}
 }
 
 void cifs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
 {
-	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
-		cifs_fscache_disable_inode_cookie(inode);
-	else
-		cifs_fscache_enable_inode_cookie(inode);
+	cifs_fscache_enable_inode_cookie(inode);
 }
 
 void cifs_fscache_reset_inode_cookie(struct inode *inode)
@@ -310,6 +315,8 @@ void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 	int ret;
 
+	WARN_ON(!cifsi->fscache);
+
 	cifs_dbg(FYI, "%s: (fsc: %p, p: %p, i: %p)\n",
 		 __func__, cifsi->fscache, page, inode);
 	ret = fscache_write_page(cifsi->fscache, page,
@@ -334,3 +341,21 @@ void __cifs_fscache_invalidate_page(struct page *page, struct inode *inode)
 	fscache_wait_on_page_write(cookie, page);
 	fscache_uncache_page(cookie, page);
 }
+
+void __cifs_fscache_wait_on_page_write(struct inode *inode, struct page *page)
+{
+	struct cifsInodeInfo *cifsi = CIFS_I(inode);
+	struct fscache_cookie *cookie = cifsi->fscache;
+
+	cifs_dbg(FYI, "%s: (0x%p/0x%p)\n", __func__, page, cookie);
+	fscache_wait_on_page_write(cookie, page);
+}
+
+void __cifs_fscache_uncache_page(struct inode *inode, struct page *page)
+{
+	struct cifsInodeInfo *cifsi = CIFS_I(inode);
+	struct fscache_cookie *cookie = cifsi->fscache;
+
+	cifs_dbg(FYI, "%s: (0x%p/0x%p)\n", __func__, page, cookie);
+	fscache_uncache_page(cookie, page);
+}