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>

1 files changed, 104 insertions, 18 deletions

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);
 }
-