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, 118 insertions, 170 deletions

diff --git a/fs/cifs/cache.c b/fs/cifs/cache.c
index 2c14020e5e1d..b4fa270ef532 100644
--- a/fs/cifs/cache.c
+++ b/fs/cifs/cache.c
@@ -46,67 +46,11 @@ void cifs_fscache_unregister(void)
 }
 
 /*
- * Key layout of CIFS server cache index object
- */
-struct cifs_server_key {
-	uint16_t	family;		/* address family */
-	__be16		port;		/* IP port */
-	union {
-		struct in_addr	ipv4_addr;
-		struct in6_addr	ipv6_addr;
-	} addr[0];
-};
-
-/*
- * Server object keyed by {IPaddress,port,family} tuple
- */
-static uint16_t cifs_server_get_key(const void *cookie_netfs_data,
-				   void *buffer, uint16_t maxbuf)
-{
-	const struct TCP_Server_Info *server = cookie_netfs_data;
-	const struct sockaddr *sa = (struct sockaddr *) &server->dstaddr;
-	const struct sockaddr_in *addr = (struct sockaddr_in *) sa;
-	const struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *) sa;
-	struct cifs_server_key *key = buffer;
-	uint16_t key_len = sizeof(struct cifs_server_key);
-
-	memset(key, 0, key_len);
-
-	/*
-	 * Should not be a problem as sin_family/sin6_family overlays
-	 * sa_family field
-	 */
-	switch (sa->sa_family) {
-	case AF_INET:
-		key->family = sa->sa_family;
-		key->port = addr->sin_port;
-		key->addr[0].ipv4_addr = addr->sin_addr;
-		key_len += sizeof(key->addr[0].ipv4_addr);
-		break;
-
-	case AF_INET6:
-		key->family = sa->sa_family;
-		key->port = addr6->sin6_port;
-		key->addr[0].ipv6_addr = addr6->sin6_addr;
-		key_len += sizeof(key->addr[0].ipv6_addr);
-		break;
-
-	default:
-		cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
-		key_len = 0;
-		break;
-	}
-
-	return key_len;
-}
-
-/*
  * Server object for FS-Cache
  */
 const struct fscache_cookie_def cifs_fscache_server_index_def = {
 	.name = "CIFS.server",
 	.type = FSCACHE_COOKIE_TYPE_INDEX,
-	.get_key = cifs_server_get_key,
 };
 
 /*
@@ -116,7 +60,7 @@ struct cifs_fscache_super_auxdata {
 	u64	resource_id;		/* unique server resource id */
 };
 
-static char *extract_sharename(const char *treename)
+char *extract_sharename(const char *treename)
 {
 	const char *src;
 	char *delim, *dst;
@@ -140,52 +84,6 @@ static char *extract_sharename(const char *treename)
 	return dst;
 }
 
-/*
- * Superblock object currently keyed by share name
- */
-static uint16_t cifs_super_get_key(const void *cookie_netfs_data, void *buffer,
-				   uint16_t maxbuf)
-{
-	const struct cifs_tcon *tcon = cookie_netfs_data;
-	char *sharename;
-	uint16_t len;
-
-	sharename = extract_sharename(tcon->treeName);
-	if (IS_ERR(sharename)) {
-		cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
-		sharename = NULL;
-		return 0;
-	}
-
-	len = strlen(sharename);
-	if (len > maxbuf)
-		return 0;
-
-	memcpy(buffer, sharename, len);
-
-	kfree(sharename);
-
-	return len;
-}
-
-static uint16_t
-cifs_fscache_super_get_aux(const void *cookie_netfs_data, void *buffer,
-			   uint16_t maxbuf)
-{
-	struct cifs_fscache_super_auxdata auxdata;
-	const struct cifs_tcon *tcon = cookie_netfs_data;
-
-	memset(&auxdata, 0, sizeof(auxdata));
-	auxdata.resource_id = tcon->resource_id;
-
-	if (maxbuf > sizeof(auxdata))
-		maxbuf = sizeof(auxdata);
-
-	memcpy(buffer, &auxdata, maxbuf);
-
-	return maxbuf;
-}
-
 static enum
 fscache_checkaux cifs_fscache_super_check_aux(void *cookie_netfs_data,
 					      const void *data,
@@ -212,36 +110,9 @@ fscache_checkaux cifs_fscache_super_check_aux(void *cookie_netfs_data,
 const struct fscache_cookie_def cifs_fscache_super_index_def = {
 	.name = "CIFS.super",
 	.type = FSCACHE_COOKIE_TYPE_INDEX,
-	.get_key = cifs_super_get_key,
-	.get_aux = cifs_fscache_super_get_aux,
 	.check_aux = cifs_fscache_super_check_aux,
 };
 
-/*
- * Auxiliary data attached to CIFS inode within the cache
- */
-struct cifs_fscache_inode_auxdata {
-	struct timespec	last_write_time;
-	struct timespec	last_change_time;
-	u64		eof;
-};
-
-static uint16_t cifs_fscache_inode_get_key(const void *cookie_netfs_data,
-					   void *buffer, uint16_t maxbuf)
-{
-	const struct cifsInodeInfo *cifsi = cookie_netfs_data;
-	uint16_t keylen;
-
-	/* use the UniqueId as the key */
-	keylen = sizeof(cifsi->uniqueid);
-	if (keylen > maxbuf)
-		keylen = 0;
-	else
-		memcpy(buffer, &cifsi->uniqueid, keylen);
-
-	return keylen;
-}
-
 static void
 cifs_fscache_inode_get_attr(const void *cookie_netfs_data, uint64_t *size)
 {
@@ -250,26 +121,6 @@ cifs_fscache_inode_get_attr(const void *cookie_netfs_data, uint64_t *size)
 	*size = cifsi->vfs_inode.i_size;
 }
 
-static uint16_t
-cifs_fscache_inode_get_aux(const void *cookie_netfs_data, void *buffer,
-			   uint16_t maxbuf)
-{
-	struct cifs_fscache_inode_auxdata auxdata;
-	const struct cifsInodeInfo *cifsi = cookie_netfs_data;
-
-	memset(&auxdata, 0, sizeof(auxdata));
-	auxdata.eof = cifsi->server_eof;
-	auxdata.last_write_time = cifsi->vfs_inode.i_mtime;
-	auxdata.last_change_time = cifsi->vfs_inode.i_ctime;
-
-	if (maxbuf > sizeof(auxdata))
-		maxbuf = sizeof(auxdata);
-
-	memcpy(buffer, &auxdata, maxbuf);
-
-	return maxbuf;
-}
-
 static enum
 fscache_checkaux cifs_fscache_inode_check_aux(void *cookie_netfs_data,
 					      const void *data,
@@ -295,8 +146,6 @@ fscache_checkaux cifs_fscache_inode_check_aux(void *cookie_netfs_data,
 const struct fscache_cookie_def cifs_fscache_inode_object_def = {
 	.name		= "CIFS.uniqueid",
 	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
-	.get_key	= cifs_fscache_inode_get_key,
 	.get_attr	= cifs_fscache_inode_get_attr,
-	.get_aux	= cifs_fscache_inode_get_aux,
 	.check_aux	= cifs_fscache_inode_check_aux,
 };
diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c
index 8d4b7bc8ae91..b89b59b01759 100644
--- a/fs/cifs/fscache.c
+++ b/fs/cifs/fscache.c
@@ -23,11 +23,63 @@
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
 
+/*
+ * Key layout of CIFS server cache index object
+ */
+struct cifs_server_key {
+	struct {
+		uint16_t	family;		/* address family */
+		__be16		port;		/* IP port */
+	} hdr;
+	union {
+		struct in_addr	ipv4_addr;
+		struct in6_addr	ipv6_addr;
+	};
+} __packed;
+
+/*
+ * Get a cookie for a server object keyed by {IPaddress,port,family} tuple
+ */
 void cifs_fscache_get_client_cookie(struct TCP_Server_Info *server)
 {
+	const struct sockaddr *sa = (struct sockaddr *) &server->dstaddr;
+	const struct sockaddr_in *addr = (struct sockaddr_in *) sa;
+	const struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *) sa;
+	struct cifs_server_key key;
+	uint16_t key_len = sizeof(key.hdr);
+
+	memset(&key, 0, sizeof(key));
+
+	/*
+	 * Should not be a problem as sin_family/sin6_family overlays
+	 * sa_family field
+	 */
+	key.hdr.family = sa->sa_family;
+	switch (sa->sa_family) {
+	case AF_INET:
+		key.hdr.port = addr->sin_port;
+		key.ipv4_addr = addr->sin_addr;
+		key_len += sizeof(key.ipv4_addr);
+		break;
+
+	case AF_INET6:
+		key.hdr.port = addr6->sin6_port;
+		key.ipv6_addr = addr6->sin6_addr;
+		key_len += sizeof(key.ipv6_addr);
+		break;
+
+	default:
+		cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
+		server->fscache = NULL;
+		return;
+	}
+
 	server->fscache =
 		fscache_acquire_cookie(cifs_fscache_netfs.primary_index,
-				&cifs_fscache_server_index_def, server, true);
+				       &cifs_fscache_server_index_def,
+				       &key, key_len,
+				       NULL, 0,
+				       server, true);
 	cifs_dbg(FYI, "%s: (0x%p/0x%p)\n",
 		 __func__, server, server->fscache);
 }
@@ -36,17 +88,29 @@ void cifs_fscache_release_client_cookie(struct TCP_Server_Info *server)
 {
 	cifs_dbg(FYI, "%s: (0x%p/0x%p)\n",
 		 __func__, server, server->fscache);
-	fscache_relinquish_cookie(server->fscache, 0);
+	fscache_relinquish_cookie(server->fscache, NULL, false);
 	server->fscache = NULL;
 }
 
 void cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
 {
 	struct TCP_Server_Info *server = tcon->ses->server;
+	char *sharename;
+
+	sharename = extract_sharename(tcon->treeName);
+	if (IS_ERR(sharename)) {
+		cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
+		tcon->fscache = NULL;
+		return;
+	}
 
 	tcon->fscache =
 		fscache_acquire_cookie(server->fscache,
-				&cifs_fscache_super_index_def, tcon, true);
+				       &cifs_fscache_super_index_def,
+				       sharename, strlen(sharename),
+				       &tcon->resource_id, sizeof(tcon->resource_id),
+				       tcon, true);
+	kfree(sharename);
 	cifs_dbg(FYI, "%s: (0x%p/0x%p)\n",
 		 __func__, server->fscache, tcon->fscache);
 }
@@ -54,10 +118,28 @@ void cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
 void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
 {
 	cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);
-	fscache_relinquish_cookie(tcon->fscache, 0);
+	fscache_relinquish_cookie(tcon->fscache, &tcon->resource_id, false);
 	tcon->fscache = NULL;
 }
 
+static void cifs_fscache_acquire_inode_cookie(struct cifsInodeInfo *cifsi,
+					      struct cifs_tcon *tcon)
+{
+	struct cifs_fscache_inode_auxdata auxdata;
+
+	memset(&auxdata, 0, sizeof(auxdata));
+	auxdata.eof = cifsi->server_eof;
+	auxdata.last_write_time = cifsi->vfs_inode.i_mtime;
+	auxdata.last_change_time = cifsi->vfs_inode.i_ctime;
+
+	cifsi->fscache =
+		fscache_acquire_cookie(tcon->fscache,
+				       &cifs_fscache_inode_object_def,
+				       &cifsi->uniqueid, sizeof(cifsi->uniqueid),
+				       &auxdata, sizeof(auxdata),
+				       cifsi, true);
+}
+
 static void cifs_fscache_enable_inode_cookie(struct inode *inode)
 {
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
@@ -67,21 +149,28 @@ static void cifs_fscache_enable_inode_cookie(struct inode *inode)
 	if (cifsi->fscache)
 		return;
 
-	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE) {
-		cifsi->fscache = fscache_acquire_cookie(tcon->fscache,
-				&cifs_fscache_inode_object_def, cifsi, true);
-		cifs_dbg(FYI, "%s: got FH cookie (0x%p/0x%p)\n",
-			 __func__, tcon->fscache, cifsi->fscache);
-	}
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE))
+		return;
+
+	cifs_fscache_acquire_inode_cookie(cifsi, tcon);
+
+	cifs_dbg(FYI, "%s: got FH cookie (0x%p/0x%p)\n",
+		 __func__, tcon->fscache, cifsi->fscache);
 }
 
 void cifs_fscache_release_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 = cifsi->vfs_inode.i_mtime;
+		auxdata.last_change_time = cifsi->vfs_inode.i_ctime;
+
 		cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cifsi->fscache);
-		fscache_relinquish_cookie(cifsi->fscache, 0);
+		fscache_relinquish_cookie(cifsi->fscache, &auxdata, false);
 		cifsi->fscache = NULL;
 	}
 }
@@ -93,7 +182,7 @@ static void cifs_fscache_disable_inode_cookie(struct inode *inode)
 	if (cifsi->fscache) {
 		cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cifsi->fscache);
 		fscache_uncache_all_inode_pages(cifsi->fscache, inode);
-		fscache_relinquish_cookie(cifsi->fscache, 1);
+		fscache_relinquish_cookie(cifsi->fscache, NULL, true);
 		cifsi->fscache = NULL;
 	}
 }
@@ -110,16 +199,14 @@ void cifs_fscache_reset_inode_cookie(struct inode *inode)
 {
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
 	struct fscache_cookie *old = cifsi->fscache;
 
 	if (cifsi->fscache) {
 		/* retire the current fscache cache and get a new one */
-		fscache_relinquish_cookie(cifsi->fscache, 1);
+		fscache_relinquish_cookie(cifsi->fscache, NULL, true);
 
-		cifsi->fscache = fscache_acquire_cookie(
-					cifs_sb_master_tcon(cifs_sb)->fscache,
-					&cifs_fscache_inode_object_def,
-					cifsi, true);
+		cifs_fscache_acquire_inode_cookie(cifsi, tcon);
 		cifs_dbg(FYI, "%s: new cookie 0x%p oldcookie 0x%p\n",
 			 __func__, cifsi->fscache, old);
 	}
@@ -239,4 +326,3 @@ void __cifs_fscache_invalidate_page(struct page *page, struct inode *inode)
 	fscache_wait_on_page_write(cookie, page);
 	fscache_uncache_page(cookie, page);
 }
-
diff --git a/fs/cifs/fscache.h b/fs/cifs/fscache.h
index 24794b6cd8ec..c7e3ac251e16 100644
--- a/fs/cifs/fscache.h
+++ b/fs/cifs/fscache.h
@@ -27,6 +27,18 @@
 
 #ifdef CONFIG_CIFS_FSCACHE
 
+/*
+ * Auxiliary data attached to CIFS inode within the cache
+ */
+struct cifs_fscache_inode_auxdata {
+	struct timespec	last_write_time;
+	struct timespec	last_change_time;
+	u64		eof;
+};
+
+/*
+ * cache.c
+ */
 extern struct fscache_netfs cifs_fscache_netfs;
 extern const struct fscache_cookie_def cifs_fscache_server_index_def;
 extern const struct fscache_cookie_def cifs_fscache_super_index_def;
@@ -34,6 +46,7 @@ extern const struct fscache_cookie_def cifs_fscache_inode_object_def;
 
 extern int cifs_fscache_register(void);
 extern void cifs_fscache_unregister(void);
+extern char *extract_sharename(const char *);
 
 /*
  * fscache.c