afs: Update the cache index structure

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>

1 files changed, 43 insertions, 196 deletions

diff --git a/fs/afs/cache.c b/fs/afs/cache.c
index 1fe8551..f62ff71 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);
 
@@ -42,23 +29,13 @@ static enum fscache_checkaux afs_vnode_cache_check_aux(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 = {
@@ -95,150 +72,26 @@ 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);
 }
 
 /*****************************************************************************/
@@ -249,20 +102,25 @@ 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);
 }
 
 /*
@@ -280,6 +138,11 @@ 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
  */
@@ -287,23 +150,21 @@ 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);
 }
 
 /*
@@ -314,43 +175,29 @@ 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;
 	}