[RFC PATCH 07/11] afs: Update the cache index structure

[David Howells <dhowells@redhat.com>]

Update the cache index structure in the following ways:

 (1) Don't use the volume name followed by the volume type as levels in the
     cache index.  Volumes can be renamed.  Use the volume ID instead.

 (2) Don't store the VLDB data for a volume in the tree.  If the volume
     database should be cached locally, then it should be done in a separate
     tree.

 (3) Expand the volume ID stored in the cache to 64 bits.

 (4) Expand the file/vnode ID stored in the cache to 96 bits.

 (5) Increment the cache structure version number to 1.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/afs/cache.c     |  239 +++++++++-------------------------------------------
 fs/afs/internal.h  |   21 -----
 fs/afs/vlocation.c |   39 +-------
 fs/afs/volume.c    |    2 
 4 files changed, 50 insertions(+), 251 deletions(-)

diff --git a/fs/afs/cache.c b/fs/afs/cache.c
index 577763c3d88b..e19a643e0c29 100644
--- a/fs/afs/cache.c
+++ b/fs/afs/cache.c
@@ -14,19 +14,6 @@
 
 static uint16_t afs_cell_cache_get_key(const void *cookie_netfs_data,
 				       void *buffer, uint16_t buflen);
-static uint16_t afs_cell_cache_get_aux(const void *cookie_netfs_data,
-				       void *buffer, uint16_t buflen);
-static enum fscache_checkaux afs_cell_cache_check_aux(void *cookie_netfs_data,
-						      const void *buffer,
-						      uint16_t buflen);
-
-static uint16_t afs_vlocation_cache_get_key(const void *cookie_netfs_data,
-					    void *buffer, uint16_t buflen);
-static uint16_t afs_vlocation_cache_get_aux(const void *cookie_netfs_data,
-					    void *buffer, uint16_t buflen);
-static enum fscache_checkaux afs_vlocation_cache_check_aux(
-	void *cookie_netfs_data, const void *buffer, uint16_t buflen);
-
 static uint16_t afs_volume_cache_get_key(const void *cookie_netfs_data,
 					 void *buffer, uint16_t buflen);
 
@@ -43,23 +30,13 @@ static void afs_vnode_cache_now_uncached(void *cookie_netfs_data);
 
 struct fscache_netfs afs_cache_netfs = {
 	.name			= "afs",
-	.version		= 0,
+	.version		= 1,
 };
 
 struct fscache_cookie_def afs_cell_cache_index_def = {
 	.name		= "AFS.cell",
 	.type		= FSCACHE_COOKIE_TYPE_INDEX,
 	.get_key	= afs_cell_cache_get_key,
-	.get_aux	= afs_cell_cache_get_aux,
-	.check_aux	= afs_cell_cache_check_aux,
-};
-
-struct fscache_cookie_def afs_vlocation_cache_index_def = {
-	.name			= "AFS.vldb",
-	.type			= FSCACHE_COOKIE_TYPE_INDEX,
-	.get_key		= afs_vlocation_cache_get_key,
-	.get_aux		= afs_vlocation_cache_get_aux,
-	.check_aux		= afs_vlocation_cache_check_aux,
 };
 
 struct fscache_cookie_def afs_volume_cache_index_def = {
@@ -97,150 +74,26 @@ static uint16_t afs_cell_cache_get_key(const void *cookie_netfs_data,
 	return klen;
 }
 
-/*
- * provide new auxiliary cache data
- */
-static uint16_t afs_cell_cache_get_aux(const void *cookie_netfs_data,
-				       void *buffer, uint16_t bufmax)
-{
-	const struct afs_cell *cell = cookie_netfs_data;
-	uint16_t dlen;
-
-	_enter("%p,%p,%u", cell, buffer, bufmax);
-
-	dlen = cell->vl_naddrs * sizeof(cell->vl_addrs[0]);
-	dlen = min(dlen, bufmax);
-	dlen &= ~(sizeof(cell->vl_addrs[0]) - 1);
-
-	memcpy(buffer, cell->vl_addrs, dlen);
-	return dlen;
-}
-
-/*
- * check that the auxiliary data indicates that the entry is still valid
- */
-static enum fscache_checkaux afs_cell_cache_check_aux(void *cookie_netfs_data,
-						      const void *buffer,
-						      uint16_t buflen)
-{
-	_leave(" = OKAY");
-	return FSCACHE_CHECKAUX_OKAY;
-}
-
-/*****************************************************************************/
-/*
- * set the key for the index entry
- */
-static uint16_t afs_vlocation_cache_get_key(const void *cookie_netfs_data,
-					    void *buffer, uint16_t bufmax)
-{
-	const struct afs_vlocation *vlocation = cookie_netfs_data;
-	uint16_t klen;
-
-	_enter("{%s},%p,%u", vlocation->vldb.name, buffer, bufmax);
-
-	klen = strnlen(vlocation->vldb.name, sizeof(vlocation->vldb.name));
-	if (klen > bufmax)
-		return 0;
-
-	memcpy(buffer, vlocation->vldb.name, klen);
-
-	_leave(" = %u", klen);
-	return klen;
-}
-
-/*
- * provide new auxiliary cache data
- */
-static uint16_t afs_vlocation_cache_get_aux(const void *cookie_netfs_data,
-					    void *buffer, uint16_t bufmax)
-{
-	const struct afs_vlocation *vlocation = cookie_netfs_data;
-	uint16_t dlen;
-
-	_enter("{%s},%p,%u", vlocation->vldb.name, buffer, bufmax);
-
-	dlen = sizeof(struct afs_cache_vlocation);
-	dlen -= offsetof(struct afs_cache_vlocation, nservers);
-	if (dlen > bufmax)
-		return 0;
-
-	memcpy(buffer, (uint8_t *)&vlocation->vldb.nservers, dlen);
-
-	_leave(" = %u", dlen);
-	return dlen;
-}
-
-/*
- * check that the auxiliary data indicates that the entry is still valid
- */
-static
-enum fscache_checkaux afs_vlocation_cache_check_aux(void *cookie_netfs_data,
-						    const void *buffer,
-						    uint16_t buflen)
-{
-	const struct afs_cache_vlocation *cvldb;
-	struct afs_vlocation *vlocation = cookie_netfs_data;
-	uint16_t dlen;
-
-	_enter("{%s},%p,%u", vlocation->vldb.name, buffer, buflen);
-
-	/* check the size of the data is what we're expecting */
-	dlen = sizeof(struct afs_cache_vlocation);
-	dlen -= offsetof(struct afs_cache_vlocation, nservers);
-	if (dlen != buflen)
-		return FSCACHE_CHECKAUX_OBSOLETE;
-
-	cvldb = container_of(buffer, struct afs_cache_vlocation, nservers);
-
-	/* if what's on disk is more valid than what's in memory, then use the
-	 * VL record from the cache */
-	if (!vlocation->valid || vlocation->vldb.rtime == cvldb->rtime) {
-		memcpy((uint8_t *)&vlocation->vldb.nservers, buffer, dlen);
-		vlocation->valid = 1;
-		_leave(" = SUCCESS [c->m]");
-		return FSCACHE_CHECKAUX_OKAY;
-	}
-
-	/* need to update the cache if the cached info differs */
-	if (memcmp(&vlocation->vldb, buffer, dlen) != 0) {
-		/* delete if the volume IDs for this name differ */
-		if (memcmp(&vlocation->vldb.vid, &cvldb->vid,
-			   sizeof(cvldb->vid)) != 0
-		    ) {
-			_leave(" = OBSOLETE");
-			return FSCACHE_CHECKAUX_OBSOLETE;
-		}
-
-		_leave(" = UPDATE");
-		return FSCACHE_CHECKAUX_NEEDS_UPDATE;
-	}
-
-	_leave(" = OKAY");
-	return FSCACHE_CHECKAUX_OKAY;
-}
-
 /*****************************************************************************/
 /*
  * set the key for the volume index entry
  */
 static uint16_t afs_volume_cache_get_key(const void *cookie_netfs_data,
-					void *buffer, uint16_t bufmax)
+					 void *buffer, uint16_t bufmax)
 {
 	const struct afs_volume *volume = cookie_netfs_data;
-	uint16_t klen;
+	struct {
+		u64 volid;
+	} __packed key;
 
 	_enter("{%u},%p,%u", volume->type, buffer, bufmax);
 
-	klen = sizeof(volume->type);
-	if (klen > bufmax)
+	if (bufmax < sizeof(key))
 		return 0;
 
-	memcpy(buffer, &volume->type, sizeof(volume->type));
-
-	_leave(" = %u", klen);
-	return klen;
-
+	key.volid = volume->vid;
+	memcpy(buffer, &key, sizeof(key));
+	return sizeof(key);
 }
 
 /*****************************************************************************/
@@ -251,20 +104,25 @@ static uint16_t afs_vnode_cache_get_key(const void *cookie_netfs_data,
 					void *buffer, uint16_t bufmax)
 {
 	const struct afs_vnode *vnode = cookie_netfs_data;
-	uint16_t klen;
+	struct {
+		u32 vnode_id[3];
+	} __packed key;
 
 	_enter("{%x,%x,%llx},%p,%u",
 	       vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
 	       buffer, bufmax);
 
-	klen = sizeof(vnode->fid.vnode);
-	if (klen > bufmax)
-		return 0;
+	/* Allow for a 96-bit key */
+	memset(&key, 0, sizeof(key));
+	key.vnode_id[0] = vnode->fid.vnode;
+	key.vnode_id[1] = 0;
+	key.vnode_id[2] = 0;
 
-	memcpy(buffer, &vnode->fid.vnode, sizeof(vnode->fid.vnode));
+	if (sizeof(key) > bufmax)
+		return 0;
 
-	_leave(" = %u", klen);
-	return klen;
+	memcpy(buffer, &key, sizeof(key));
+	return sizeof(key);
 }
 
 /*
@@ -282,6 +140,11 @@ static void afs_vnode_cache_get_attr(const void *cookie_netfs_data,
 	*size = vnode->status.size;
 }
 
+struct afs_vnode_cache_aux {
+	u64 data_version;
+	u32 fid_unique;
+} __packed;
+
 /*
  * provide new auxiliary cache data
  */
@@ -289,23 +152,21 @@ static uint16_t afs_vnode_cache_get_aux(const void *cookie_netfs_data,
 					void *buffer, uint16_t bufmax)
 {
 	const struct afs_vnode *vnode = cookie_netfs_data;
-	uint16_t dlen;
+	struct afs_vnode_cache_aux aux;
 
 	_enter("{%x,%x,%Lx},%p,%u",
 	       vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
 	       buffer, bufmax);
 
-	dlen = sizeof(vnode->fid.unique) + sizeof(vnode->status.data_version);
-	if (dlen > bufmax)
-		return 0;
+	memset(&aux, 0, sizeof(aux));
+	aux.data_version = vnode->status.data_version;
+	aux.fid_unique = vnode->fid.unique;
 
-	memcpy(buffer, &vnode->fid.unique, sizeof(vnode->fid.unique));
-	buffer += sizeof(vnode->fid.unique);
-	memcpy(buffer, &vnode->status.data_version,
-	       sizeof(vnode->status.data_version));
+	if (bufmax < sizeof(aux))
+		return 0;
 
-	_leave(" = %u", dlen);
-	return dlen;
+	memcpy(buffer, &aux, sizeof(aux));
+	return sizeof(aux);
 }
 
 /*
@@ -316,43 +177,29 @@ static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
 						       uint16_t buflen)
 {
 	struct afs_vnode *vnode = cookie_netfs_data;
-	uint16_t dlen;
+	struct afs_vnode_cache_aux aux;
 
 	_enter("{%x,%x,%llx},%p,%u",
 	       vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
 	       buffer, buflen);
 
+	memcpy(&aux, buffer, sizeof(aux));
+
 	/* check the size of the data is what we're expecting */
-	dlen = sizeof(vnode->fid.unique) + sizeof(vnode->status.data_version);
-	if (dlen != buflen) {
-		_leave(" = OBSOLETE [len %hx != %hx]", dlen, buflen);
+	if (buflen != sizeof(aux)) {
+		_leave(" = OBSOLETE [len %hx != %zx]", buflen, sizeof(aux));
 		return FSCACHE_CHECKAUX_OBSOLETE;
 	}
 
-	if (memcmp(buffer,
-		   &vnode->fid.unique,
-		   sizeof(vnode->fid.unique)
-		   ) != 0) {
-		unsigned unique;
-
-		memcpy(&unique, buffer, sizeof(unique));
-
+	if (vnode->fid.unique != aux.fid_unique) {
 		_leave(" = OBSOLETE [uniq %x != %x]",
-		       unique, vnode->fid.unique);
+		       aux.fid_unique, vnode->fid.unique);
 		return FSCACHE_CHECKAUX_OBSOLETE;
 	}
 
-	if (memcmp(buffer + sizeof(vnode->fid.unique),
-		   &vnode->status.data_version,
-		   sizeof(vnode->status.data_version)
-		   ) != 0) {
-		afs_dataversion_t version;
-
-		memcpy(&version, buffer + sizeof(vnode->fid.unique),
-		       sizeof(version));
-
+	if (vnode->status.data_version != aux.data_version) {
 		_leave(" = OBSOLETE [vers %llx != %llx]",
-		       version, vnode->status.data_version);
+		       aux.data_version, vnode->status.data_version);
 		return FSCACHE_CHECKAUX_OBSOLETE;
 	}
 
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index e0484a38c9ce..0ffdb02a58cb 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -189,14 +189,6 @@ static inline struct afs_super_info *AFS_FS_S(struct super_block *sb)
 extern struct file_system_type afs_fs_type;
 
 /*
- * entry in the cached cell catalogue
- */
-struct afs_cache_cell {
-	char		name[AFS_MAXCELLNAME];	/* cell name (padded with NULs) */
-	struct in_addr	vl_servers[15];		/* cached cell VL servers */
-};
-
-/*
  * AFS network namespace record.
  */
 struct afs_net {
@@ -293,14 +285,6 @@ struct afs_cache_vlocation {
 };
 
 /*
- * volume -> vnode hash table entry
- */
-struct afs_cache_vhash {
-	afs_voltype_t		vtype;		/* which volume variation */
-	uint8_t			hash_bucket;	/* which hash bucket this represents */
-} __attribute__((packed));
-
-/*
  * AFS volume location record
  */
 struct afs_vlocation {
@@ -310,9 +294,6 @@ struct afs_vlocation {
 	struct list_head	grave;		/* link in master graveyard list */
 	struct list_head	update;		/* link in master update list */
 	struct afs_cell		*cell;		/* cell to which volume belongs */
-#ifdef CONFIG_AFS_FSCACHE
-	struct fscache_cookie	*cache;		/* caching cookie */
-#endif
 	struct afs_cache_vlocation vldb;	/* volume information DB record */
 	struct afs_volume	*vols[3];	/* volume access record pointer (index by type) */
 	wait_queue_head_t	waitq;		/* status change waitqueue */
@@ -472,12 +453,10 @@ struct afs_interface {
 #ifdef CONFIG_AFS_FSCACHE
 extern struct fscache_netfs afs_cache_netfs;
 extern struct fscache_cookie_def afs_cell_cache_index_def;
-extern struct fscache_cookie_def afs_vlocation_cache_index_def;
 extern struct fscache_cookie_def afs_volume_cache_index_def;
 extern struct fscache_cookie_def afs_vnode_cache_index_def;
 #else
 #define afs_cell_cache_index_def	(*(struct fscache_cookie_def *) NULL)
-#define afs_vlocation_cache_index_def	(*(struct fscache_cookie_def *) NULL)
 #define afs_volume_cache_index_def	(*(struct fscache_cookie_def *) NULL)
 #define afs_vnode_cache_index_def	(*(struct fscache_cookie_def *) NULL)
 #endif
diff --git a/fs/afs/vlocation.c b/fs/afs/vlocation.c
index ccb7aacfbeca..d9a5d7acdb86 100644
--- a/fs/afs/vlocation.c
+++ b/fs/afs/vlocation.c
@@ -273,10 +273,6 @@ static void afs_vlocation_apply_update(struct afs_vlocation *vl,
 		       vl->vldb.name, vldb->name);
 
 	vl->vldb = *vldb;
-
-#ifdef CONFIG_AFS_FSCACHE
-	fscache_update_cookie(vl->cache);
-#endif
 }
 
 /*
@@ -295,27 +291,12 @@ static int afs_vlocation_fill_in_record(struct afs_vlocation *vl,
 
 	memset(&vldb, 0, sizeof(vldb));
 
-	/* see if we have an in-cache copy (will set vl->valid if there is) */
-#ifdef CONFIG_AFS_FSCACHE
-	vl->cache = fscache_acquire_cookie(vl->cell->cache,
-					   &afs_vlocation_cache_index_def, vl,
-					   true);
-#endif
-
-	if (vl->valid) {
-		/* try to update a known volume in the cell VL databases by
-		 * ID as the name may have changed */
-		_debug("found in cache");
-		ret = afs_vlocation_update_record(vl, key, &vldb);
-	} else {
-		/* try to look up an unknown volume in the cell VL databases by
-		 * name */
-		ret = afs_vlocation_access_vl_by_name(vl, key, &vldb);
-		if (ret < 0) {
-			printk("kAFS: failed to locate '%s' in cell '%s'\n",
-			       vl->vldb.name, vl->cell->name);
-			return ret;
-		}
+	/* Try to look up an unknown volume in the cell VL databases by name */
+	ret = afs_vlocation_access_vl_by_name(vl, key, &vldb);
+	if (ret < 0) {
+		printk("kAFS: failed to locate '%s' in cell '%s'\n",
+		       vl->vldb.name, vl->cell->name);
+		return ret;
 	}
 
 	afs_vlocation_apply_update(vl, &vldb);
@@ -414,11 +395,6 @@ struct afs_vlocation *afs_vlocation_lookup(struct afs_net *net,
 	spin_unlock(&vl->lock);
 	wake_up(&vl->waitq);
 
-	/* update volume entry in local cache */
-#ifdef CONFIG_AFS_FSCACHE
-	fscache_update_cookie(vl->cache);
-#endif
-
 	/* schedule for regular updates */
 	afs_vlocation_queue_for_updates(net, vl);
 	goto success;
@@ -522,9 +498,6 @@ static void afs_vlocation_destroy(struct afs_vlocation *vl)
 {
 	_enter("%p", vl);
 
-#ifdef CONFIG_AFS_FSCACHE
-	fscache_relinquish_cookie(vl->cache, 0);
-#endif
 	afs_put_cell(vl->cell);
 	kfree(vl);
 }
diff --git a/fs/afs/volume.c b/fs/afs/volume.c
index 3d5363e0b7e1..bc52203695b7 100644
--- a/fs/afs/volume.c
+++ b/fs/afs/volume.c
@@ -125,7 +125,7 @@ struct afs_volume *afs_volume_lookup(struct afs_mount_params *params)
 
 	/* attach the cache and volume location */
 #ifdef CONFIG_AFS_FSCACHE
-	volume->cache = fscache_acquire_cookie(vlocation->cache,
+	volume->cache = fscache_acquire_cookie(volume->cell->cache,
 					       &afs_volume_cache_index_def,
 					       volume, true);
 #endif