ceph: use fscache as a local presisent cache

Adding support for fscache to the Ceph filesystem. This would bring it to on
par with some of the other network filesystems in Linux (like NFS, AFS, etc...)

In order to mount the filesystem with fscache the 'fsc' mount option must be
passed.

Signed-off-by: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Sage Weil <sage@inktank.com>

1 files changed, 138 insertions, 0 deletions

diff --git a/fs/ceph/cache.h b/fs/ceph/cache.h
new file mode 100644
index 00000000000..0ea95cb7f38
--- /dev/null
+++ b/fs/ceph/cache.h
@@ -0,0 +1,138 @@
+/*
+ * Ceph cache definitions.
+ *
+ *  Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
+ *  Written by Milosz Tanski (milosz@adfin.com)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#ifndef _CEPH_CACHE_H
+#define _CEPH_CACHE_H
+
+#ifdef CONFIG_CEPH_FSCACHE
+
+int ceph_fscache_register(void);
+void ceph_fscache_unregister(void);
+
+int ceph_fscache_register_fs(struct ceph_fs_client* fsc);
+void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc);
+
+void ceph_fscache_inode_init(struct ceph_inode_info *ci);
+void ceph_fscache_register_inode_cookie(struct ceph_fs_client* fsc,
+					struct ceph_inode_info* ci);
+void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci);
+
+int ceph_readpage_from_fscache(struct inode *inode, struct page *page);
+int ceph_readpages_from_fscache(struct inode *inode,
+				struct address_space *mapping,
+				struct list_head *pages,
+				unsigned *nr_pages);
+void ceph_readpage_to_fscache(struct inode *inode, struct page *page);
+void ceph_invalidate_fscache_page(struct inode* inode, struct page *page);
+void ceph_queue_revalidate(struct inode *inode);
+
+static inline void ceph_fscache_invalidate(struct inode *inode)
+{
+	fscache_invalidate(ceph_inode(inode)->fscache);
+}
+
+static inline int ceph_release_fscache_page(struct page *page, gfp_t gfp)
+{
+	struct inode* inode = page->mapping->host;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	return fscache_maybe_release_page(ci->fscache, page, gfp);
+}
+
+#else
+
+static inline int ceph_fscache_register(void)
+{
+	return 0;
+}
+
+static inline void ceph_fscache_unregister(void)
+{
+}
+
+static inline int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
+{
+	return 0;
+}
+
+static inline void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
+{
+}
+
+static inline void ceph_fscache_inode_init(struct ceph_inode_info *ci)
+{
+}
+
+static inline void ceph_fscache_register_inode_cookie(struct ceph_fs_client* parent_fsc,
+						      struct ceph_inode_info* ci)
+{
+}
+
+static inline void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
+{
+}
+
+static inline int ceph_readpage_from_fscache(struct inode* inode,
+					     struct page *page)
+{
+	return -ENOBUFS;
+}
+
+static inline int ceph_readpages_from_fscache(struct inode *inode,
+					      struct address_space *mapping,
+					      struct list_head *pages,
+					      unsigned *nr_pages)
+{
+	return -ENOBUFS;
+}
+
+static inline void ceph_readpage_to_fscache(struct inode *inode,
+					    struct page *page)
+{
+}
+
+static inline void ceph_fscache_invalidate(struct inode *inode)
+{
+}
+
+static inline void ceph_invalidate_fscache_page(struct inode *inode,
+						struct page *page)
+{
+}
+
+static inline int ceph_release_fscache_page(struct page *page, gfp_t gfp)
+{
+	return 1;
+}
+
+static inline void ceph_fscache_readpages_cancel(struct inode *inode,
+						 struct list_head *pages)
+{
+}
+
+static inline void ceph_queue_revalidate(struct inode *inode)
+{
+}
+
+#endif
+
+#endif