fscache: Attach the index key and aux data to the cookie

Attach copies of the index key and auxiliary data to the fscache cookie so
that:

 (1) The callbacks to the netfs for this stuff can be eliminated.  This
     can simplify things in the cache as the information is still
     available, even after the cache has relinquished the cookie.

 (2) Simplifies the locking requirements of accessing the information as we
     don't have to worry about the netfs object going away on us.

 (3) The cache can do lazy updating of the coherency information on disk.
     As long as the cache is flushed before reboot/poweroff, there's no
     need to update the coherency info on disk every time it changes.

 (4) Cookies can be hashed or put in a tree as the index key is easily
     available.  This allows:

     (a) Checks for duplicate cookies can be made at the top fscache layer
     	 rather than down in the bowels of the cache backend.

     (b) Caching can be added to a netfs object that has a cookie if the
     	 cache is brought online after the netfs object is allocated.

A certain amount of space is made in the cookie for inline copies of the
data, but if it won't fit there, extra memory will be allocated for it.

The downside of this is that live cache operation requires more memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Anna Schumaker <anna.schumaker@netapp.com>
Tested-by: Steve Dickson <steved@redhat.com>

3 files changed, 94 insertions, 145 deletions

diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c
index 0ee4b93d36ea..6fd3679b7137 100644
--- a/fs/nfs/fscache-index.c
+++ b/fs/nfs/fscache-index.c
@@ -50,59 +50,6 @@ void nfs_fscache_unregister(void)
 }
 
 /*
- * Layout of the key for an NFS server cache object.
- */
-struct nfs_server_key {
-	uint16_t	nfsversion;		/* NFS protocol version */
-	uint16_t	family;			/* address family */
-	uint16_t	port;			/* IP port */
-	union {
-		struct in_addr	ipv4_addr;	/* IPv4 address */
-		struct in6_addr ipv6_addr;	/* IPv6 address */
-	} addr[0];
-};
-
-/*
- * Generate a key to describe a server in the main NFS index
- * - We return the length of the key, or 0 if we can't generate one
- */
-static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
-				   void *buffer, uint16_t bufmax)
-{
-	const struct nfs_client *clp = cookie_netfs_data;
-	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
-	const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
-	struct nfs_server_key *key = buffer;
-	uint16_t len = sizeof(struct nfs_server_key);
-
-	memset(key, 0, len);
-	key->nfsversion = clp->rpc_ops->version;
-	key->family = clp->cl_addr.ss_family;
-
-	switch (clp->cl_addr.ss_family) {
-	case AF_INET:
-		key->port = sin->sin_port;
-		key->addr[0].ipv4_addr = sin->sin_addr;
-		len += sizeof(key->addr[0].ipv4_addr);
-		break;
-
-	case AF_INET6:
-		key->port = sin6->sin6_port;
-		key->addr[0].ipv6_addr = sin6->sin6_addr;
-		len += sizeof(key->addr[0].ipv6_addr);
-		break;
-
-	default:
-		printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
-		       clp->cl_addr.ss_family);
-		len = 0;
-		break;
-	}
-
-	return len;
-}
-
-/*
  * Define the server object for FS-Cache.  This is used to describe a server
  * object to fscache_acquire_cookie().  It is keyed by the NFS protocol and
  * server address parameters.
@@ -110,33 +57,9 @@ static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
 const struct fscache_cookie_def nfs_fscache_server_index_def = {
 	.name		= "NFS.server",
 	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
-	.get_key	= nfs_server_get_key,
 };
 
 /*
- * Generate a key to describe a superblock key in the main NFS index
- */
-static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
-				  void *buffer, uint16_t bufmax)
-{
-	const struct nfs_fscache_key *key;
-	const struct nfs_server *nfss = cookie_netfs_data;
-	uint16_t len;
-
-	key = nfss->fscache_key;
-	len = sizeof(key->key) + key->key.uniq_len;
-	if (len > bufmax) {
-		len = 0;
-	} else {
-		memcpy(buffer, &key->key, sizeof(key->key));
-		memcpy(buffer + sizeof(key->key),
-		       key->key.uniquifier, key->key.uniq_len);
-	}
-
-	return len;
-}
-
-/*
  * Define the superblock object for FS-Cache.  This is used to describe a
  * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
  * parameters that might cause a separate superblock.
@@ -144,41 +67,9 @@ static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
 const struct fscache_cookie_def nfs_fscache_super_index_def = {
 	.name		= "NFS.super",
 	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
-	.get_key	= nfs_super_get_key,
 };
 
 /*
- * Definition of the auxiliary data attached to NFS inode storage objects
- * within the cache.
- *
- * The contents of this struct are recorded in the on-disk local cache in the
- * auxiliary data attached to the data storage object backing an inode.  This
- * permits coherency to be managed when a new inode binds to an already extant
- * cache object.
- */
-struct nfs_fscache_inode_auxdata {
-	struct timespec	mtime;
-	struct timespec	ctime;
-	loff_t		size;
-	u64		change_attr;
-};
-
-/*
- * Generate a key to describe an NFS inode in an NFS server's index
- */
-static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data,
-					  void *buffer, uint16_t bufmax)
-{
-	const struct nfs_inode *nfsi = cookie_netfs_data;
-	uint16_t nsize;
-
-	/* use the inode's NFS filehandle as the key */
-	nsize = nfsi->fh.size;
-	memcpy(buffer, nfsi->fh.data, nsize);
-	return nsize;
-}
-
-/*
  * Get certain file attributes from the netfs data
  * - This function can be absent for an index
  * - Not permitted to return an error
@@ -193,35 +84,6 @@ static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data,
 }
 
 /*
- * Get the auxiliary data from netfs data
- * - This function can be absent if the index carries no state data
- * - Should store the auxiliary data in the buffer
- * - Should return the amount of amount stored
- * - Not permitted to return an error
- * - The netfs data from the cookie being used as the source is presented
- */
-static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data,
-					  void *buffer, uint16_t bufmax)
-{
-	struct nfs_fscache_inode_auxdata auxdata;
-	const struct nfs_inode *nfsi = cookie_netfs_data;
-
-	memset(&auxdata, 0, sizeof(auxdata));
-	auxdata.size = nfsi->vfs_inode.i_size;
-	auxdata.mtime = nfsi->vfs_inode.i_mtime;
-	auxdata.ctime = nfsi->vfs_inode.i_ctime;
-
-	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
-		auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
-
-	if (bufmax > sizeof(auxdata))
-		bufmax = sizeof(auxdata);
-
-	memcpy(buffer, &auxdata, bufmax);
-	return bufmax;
-}
-
-/*
  * Consult the netfs about the state of an object
  * - This function can be absent if the index carries no state data
  * - The netfs data from the cookie being used as the target is
@@ -288,9 +150,7 @@ static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
 const struct fscache_cookie_def nfs_fscache_inode_object_def = {
 	.name		= "NFS.fh",
 	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
-	.get_key	= nfs_fscache_inode_get_key,
 	.get_attr	= nfs_fscache_inode_get_attr,
-	.get_aux	= nfs_fscache_inode_get_aux,
 	.check_aux	= nfs_fscache_inode_check_aux,
 	.get_context	= nfs_fh_get_context,
 	.put_context	= nfs_fh_put_context,
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index d63bea8bbfbb..c45ba2691cee 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -18,6 +18,7 @@
 #include <linux/in6.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
+#include <linux/iversion.h>
 
 #include "internal.h"
 #include "iostat.h"
@@ -29,6 +30,21 @@ static struct rb_root nfs_fscache_keys = RB_ROOT;
 static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
 
 /*
+ * Layout of the key for an NFS server cache object.
+ */
+struct nfs_server_key {
+	struct {
+		uint16_t	nfsversion;		/* NFS protocol version */
+		uint16_t	family;			/* address family */
+		__be16		port;			/* IP port */
+	} hdr;
+	union {
+		struct in_addr	ipv4_addr;	/* IPv4 address */
+		struct in6_addr ipv6_addr;	/* IPv6 address */
+	};
+} __packed;
+
+/*
  * Get the per-client index cookie for an NFS client if the appropriate mount
  * flag was set
  * - We always try and get an index cookie for the client, but get filehandle
@@ -36,9 +52,40 @@ static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
  */
 void nfs_fscache_get_client_cookie(struct nfs_client *clp)
 {
+	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
+	const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
+	struct nfs_server_key key;
+	uint16_t len = sizeof(key.hdr);
+
+	memset(&key, 0, sizeof(key));
+	key.hdr.nfsversion = clp->rpc_ops->version;
+	key.hdr.family = clp->cl_addr.ss_family;
+
+	switch (clp->cl_addr.ss_family) {
+	case AF_INET:
+		key.hdr.port = sin->sin_port;
+		key.ipv4_addr = sin->sin_addr;
+		len += sizeof(key.ipv4_addr);
+		break;
+
+	case AF_INET6:
+		key.hdr.port = sin6->sin6_port;
+		key.ipv6_addr = sin6->sin6_addr;
+		len += sizeof(key.ipv6_addr);
+		break;
+
+	default:
+		printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
+		       clp->cl_addr.ss_family);
+		clp->fscache = NULL;
+		return;
+	}
+
 	/* create a cache index for looking up filehandles */
 	clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
 					      &nfs_fscache_server_index_def,
+					      &key, len,
+					      NULL, 0,
 					      clp, true);
 	dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
 		 clp, clp->fscache);
@@ -52,7 +99,7 @@ void nfs_fscache_release_client_cookie(struct nfs_client *clp)
 	dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
 		 clp, clp->fscache);
 
-	fscache_relinquish_cookie(clp->fscache, 0);
+	fscache_relinquish_cookie(clp->fscache, NULL, false);
 	clp->fscache = NULL;
 }
 
@@ -139,6 +186,8 @@ void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int
 	/* create a cache index for looking up filehandles */
 	nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
 					       &nfs_fscache_super_index_def,
+					       key, sizeof(*key) + ulen,
+					       NULL, 0,
 					       nfss, true);
 	dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
 		 nfss, nfss->fscache);
@@ -163,7 +212,7 @@ void nfs_fscache_release_super_cookie(struct super_block *sb)
 	dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
 		 nfss, nfss->fscache);
 
-	fscache_relinquish_cookie(nfss->fscache, 0);
+	fscache_relinquish_cookie(nfss->fscache, NULL, false);
 	nfss->fscache = NULL;
 
 	if (nfss->fscache_key) {
@@ -180,13 +229,25 @@ void nfs_fscache_release_super_cookie(struct super_block *sb)
  */
 void nfs_fscache_init_inode(struct inode *inode)
 {
+	struct nfs_fscache_inode_auxdata auxdata;
 	struct nfs_inode *nfsi = NFS_I(inode);
 
 	nfsi->fscache = NULL;
 	if (!S_ISREG(inode->i_mode))
 		return;
+
+	memset(&auxdata, 0, sizeof(auxdata));
+	auxdata.size = nfsi->vfs_inode.i_size;
+	auxdata.mtime = nfsi->vfs_inode.i_mtime;
+	auxdata.ctime = nfsi->vfs_inode.i_ctime;
+
+	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
+		auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
+
 	nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
 					       &nfs_fscache_inode_object_def,
+					       nfsi->fh.data, nfsi->fh.size,
+					       &auxdata, sizeof(auxdata),
 					       nfsi, false);
 }
 
@@ -195,12 +256,17 @@ void nfs_fscache_init_inode(struct inode *inode)
  */
 void nfs_fscache_clear_inode(struct inode *inode)
 {
+	struct nfs_fscache_inode_auxdata auxdata;
 	struct nfs_inode *nfsi = NFS_I(inode);
 	struct fscache_cookie *cookie = nfs_i_fscache(inode);
 
 	dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
 
-	fscache_relinquish_cookie(cookie, false);
+	memset(&auxdata, 0, sizeof(auxdata));
+	auxdata.size = nfsi->vfs_inode.i_size;
+	auxdata.mtime = nfsi->vfs_inode.i_mtime;
+	auxdata.ctime = nfsi->vfs_inode.i_ctime;
+	fscache_relinquish_cookie(cookie, &auxdata, false);
 	nfsi->fscache = NULL;
 }
 
@@ -232,20 +298,27 @@ static bool nfs_fscache_can_enable(void *data)
  */
 void nfs_fscache_open_file(struct inode *inode, struct file *filp)
 {
+	struct nfs_fscache_inode_auxdata auxdata;
 	struct nfs_inode *nfsi = NFS_I(inode);
 	struct fscache_cookie *cookie = nfs_i_fscache(inode);
 
 	if (!fscache_cookie_valid(cookie))
 		return;
 
+	memset(&auxdata, 0, sizeof(auxdata));
+	auxdata.size = nfsi->vfs_inode.i_size;
+	auxdata.mtime = nfsi->vfs_inode.i_mtime;
+	auxdata.ctime = nfsi->vfs_inode.i_ctime;
+
 	if (inode_is_open_for_write(inode)) {
 		dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
 		clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
-		fscache_disable_cookie(cookie, true);
+		fscache_disable_cookie(cookie, &auxdata, true);
 		fscache_uncache_all_inode_pages(cookie, inode);
 	} else {
 		dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
-		fscache_enable_cookie(cookie, nfs_fscache_can_enable, inode);
+		fscache_enable_cookie(cookie, &auxdata,
+				      nfs_fscache_can_enable, inode);
 		if (fscache_cookie_enabled(cookie))
 			set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
 	}
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index d7fe3e799f2f..96e989f579d1 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -57,6 +57,22 @@ struct nfs_fscache_key {
 };
 
 /*
+ * Definition of the auxiliary data attached to NFS inode storage objects
+ * within the cache.
+ *
+ * The contents of this struct are recorded in the on-disk local cache in the
+ * auxiliary data attached to the data storage object backing an inode.  This
+ * permits coherency to be managed when a new inode binds to an already extant
+ * cache object.
+ */
+struct nfs_fscache_inode_auxdata {
+	struct timespec	mtime;
+	struct timespec	ctime;
+	loff_t		size;
+	u64		change_attr;
+};
+
+/*
  * fscache-index.c
  */
 extern struct fscache_netfs nfs_fscache_netfs;