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, 33 insertions, 2 deletions

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 6627b26a800..6a0951e4304 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -17,6 +17,7 @@
 
 #include "super.h"
 #include "mds_client.h"
+#include "cache.h"
 
 #include <linux/ceph/ceph_features.h>
 #include <linux/ceph/decode.h>
@@ -142,6 +143,8 @@ enum {
 	Opt_nodcache,
 	Opt_ino32,
 	Opt_noino32,
+	Opt_fscache,
+	Opt_nofscache
 };
 
 static match_table_t fsopt_tokens = {
@@ -167,6 +170,8 @@ static match_table_t fsopt_tokens = {
 	{Opt_nodcache, "nodcache"},
 	{Opt_ino32, "ino32"},
 	{Opt_noino32, "noino32"},
+	{Opt_fscache, "fsc"},
+	{Opt_nofscache, "nofsc"},
 	{-1, NULL}
 };
 
@@ -260,6 +265,12 @@ static int parse_fsopt_token(char *c, void *private)
 	case Opt_noino32:
 		fsopt->flags &= ~CEPH_MOUNT_OPT_INO32;
 		break;
+	case Opt_fscache:
+		fsopt->flags |= CEPH_MOUNT_OPT_FSCACHE;
+		break;
+	case Opt_nofscache:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_FSCACHE;
+		break;
 	default:
 		BUG_ON(token);
 	}
@@ -422,6 +433,10 @@ static int ceph_show_options(struct seq_file *m, struct dentry *root)
 		seq_puts(m, ",dcache");
 	else
 		seq_puts(m, ",nodcache");
+	if (fsopt->flags & CEPH_MOUNT_OPT_FSCACHE)
+		seq_puts(m, ",fsc");
+	else
+		seq_puts(m, ",nofsc");
 
 	if (fsopt->wsize)
 		seq_printf(m, ",wsize=%d", fsopt->wsize);
@@ -530,11 +545,18 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 	if (!fsc->wb_pagevec_pool)
 		goto fail_trunc_wq;
 
+	/* setup fscache */
+	if ((fsopt->flags & CEPH_MOUNT_OPT_FSCACHE) &&
+	    (ceph_fscache_register_fs(fsc) != 0))
+		goto fail_fscache;
+
 	/* caps */
 	fsc->min_caps = fsopt->max_readdir;
 
 	return fsc;
 
+fail_fscache:
+	ceph_fscache_unregister_fs(fsc);
 fail_trunc_wq:
 	destroy_workqueue(fsc->trunc_wq);
 fail_pg_inv_wq:
@@ -554,6 +576,8 @@ static void destroy_fs_client(struct ceph_fs_client *fsc)
 {
 	dout("destroy_fs_client %p\n", fsc);
 
+	ceph_fscache_unregister_fs(fsc);
+
 	destroy_workqueue(fsc->wb_wq);
 	destroy_workqueue(fsc->pg_inv_wq);
 	destroy_workqueue(fsc->trunc_wq);
@@ -588,6 +612,8 @@ static void ceph_inode_init_once(void *foo)
 
 static int __init init_caches(void)
 {
+	int error = -ENOMEM;
+
 	ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
 				      sizeof(struct ceph_inode_info),
 				      __alignof__(struct ceph_inode_info),
@@ -611,15 +637,17 @@ static int __init init_caches(void)
 	if (ceph_file_cachep == NULL)
 		goto bad_file;
 
-	return 0;
+	if ((error = ceph_fscache_register()))
+		goto bad_file;
 
+	return 0;
 bad_file:
 	kmem_cache_destroy(ceph_dentry_cachep);
 bad_dentry:
 	kmem_cache_destroy(ceph_cap_cachep);
 bad_cap:
 	kmem_cache_destroy(ceph_inode_cachep);
-	return -ENOMEM;
+	return error;
 }
 
 static void destroy_caches(void)
@@ -629,10 +657,13 @@ static void destroy_caches(void)
 	 * destroy cache.
 	 */
 	rcu_barrier();
+
 	kmem_cache_destroy(ceph_inode_cachep);
 	kmem_cache_destroy(ceph_cap_cachep);
 	kmem_cache_destroy(ceph_dentry_cachep);
 	kmem_cache_destroy(ceph_file_cachep);
+
+	ceph_fscache_unregister();
 }