Initial import

1 files changed, 402 insertions, 0 deletions

diff --git a/fs/afs/cache.c b/fs/afs/cache.c
new file mode 100644
index 000000000..577763c3d
--- /dev/null
+++ b/fs/afs/cache.c
@@ -0,0 +1,402 @@
+/* AFS caching stuff
+ *
+ * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/sched.h>
+#include "internal.h"
+
+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);
+
+static uint16_t afs_vnode_cache_get_key(const void *cookie_netfs_data,
+					void *buffer, uint16_t buflen);
+static void afs_vnode_cache_get_attr(const void *cookie_netfs_data,
+				     uint64_t *size);
+static uint16_t afs_vnode_cache_get_aux(const void *cookie_netfs_data,
+					void *buffer, uint16_t buflen);
+static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
+						       const void *buffer,
+						       uint16_t buflen);
+static void afs_vnode_cache_now_uncached(void *cookie_netfs_data);
+
+struct fscache_netfs afs_cache_netfs = {
+	.name			= "afs",
+	.version		= 0,
+};
+
+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 = {
+	.name		= "AFS.volume",
+	.type		= FSCACHE_COOKIE_TYPE_INDEX,
+	.get_key	= afs_volume_cache_get_key,
+};
+
+struct fscache_cookie_def afs_vnode_cache_index_def = {
+	.name			= "AFS.vnode",
+	.type			= FSCACHE_COOKIE_TYPE_DATAFILE,
+	.get_key		= afs_vnode_cache_get_key,
+	.get_attr		= afs_vnode_cache_get_attr,
+	.get_aux		= afs_vnode_cache_get_aux,
+	.check_aux		= afs_vnode_cache_check_aux,
+	.now_uncached		= afs_vnode_cache_now_uncached,
+};
+
+/*
+ * set the key for the index entry
+ */
+static uint16_t afs_cell_cache_get_key(const void *cookie_netfs_data,
+				       void *buffer, uint16_t bufmax)
+{
+	const struct afs_cell *cell = cookie_netfs_data;
+	uint16_t klen;
+
+	_enter("%p,%p,%u", cell, buffer, bufmax);
+
+	klen = strlen(cell->name);
+	if (klen > bufmax)
+		return 0;
+
+	memcpy(buffer, cell->name, klen);
+	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)
+{
+	const struct afs_volume *volume = cookie_netfs_data;
+	uint16_t klen;
+
+	_enter("{%u},%p,%u", volume->type, buffer, bufmax);
+
+	klen = sizeof(volume->type);
+	if (klen > bufmax)
+		return 0;
+
+	memcpy(buffer, &volume->type, sizeof(volume->type));
+
+	_leave(" = %u", klen);
+	return klen;
+
+}
+
+/*****************************************************************************/
+/*
+ * set the key for the index entry
+ */
+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;
+
+	_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;
+
+	memcpy(buffer, &vnode->fid.vnode, sizeof(vnode->fid.vnode));
+
+	_leave(" = %u", klen);
+	return klen;
+}
+
+/*
+ * provide updated file attributes
+ */
+static void afs_vnode_cache_get_attr(const void *cookie_netfs_data,
+				     uint64_t *size)
+{
+	const struct afs_vnode *vnode = cookie_netfs_data;
+
+	_enter("{%x,%x,%llx},",
+	       vnode->fid.vnode, vnode->fid.unique,
+	       vnode->status.data_version);
+
+	*size = vnode->status.size;
+}
+
+/*
+ * provide new auxiliary cache data
+ */
+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;
+
+	_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;
+
+	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));
+
+	_leave(" = %u", dlen);
+	return dlen;
+}
+
+/*
+ * check that the auxiliary data indicates that the entry is still valid
+ */
+static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
+						       const void *buffer,
+						       uint16_t buflen)
+{
+	struct afs_vnode *vnode = cookie_netfs_data;
+	uint16_t dlen;
+
+	_enter("{%x,%x,%llx},%p,%u",
+	       vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
+	       buffer, buflen);
+
+	/* 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);
+		return FSCACHE_CHECKAUX_OBSOLETE;
+	}
+
+	if (memcmp(buffer,
+		   &vnode->fid.unique,
+		   sizeof(vnode->fid.unique)
+		   ) != 0) {
+		unsigned unique;
+
+		memcpy(&unique, buffer, sizeof(unique));
+
+		_leave(" = OBSOLETE [uniq %x != %x]",
+		       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));
+
+		_leave(" = OBSOLETE [vers %llx != %llx]",
+		       version, vnode->status.data_version);
+		return FSCACHE_CHECKAUX_OBSOLETE;
+	}
+
+	_leave(" = SUCCESS");
+	return FSCACHE_CHECKAUX_OKAY;
+}
+
+/*
+ * indication the cookie is no longer uncached
+ * - this function is called when the backing store currently caching a cookie
+ *   is removed
+ * - the netfs should use this to clean up any markers indicating cached pages
+ * - this is mandatory for any object that may have data
+ */
+static void afs_vnode_cache_now_uncached(void *cookie_netfs_data)
+{
+	struct afs_vnode *vnode = cookie_netfs_data;
+	struct pagevec pvec;
+	pgoff_t first;
+	int loop, nr_pages;
+
+	_enter("{%x,%x,%Lx}",
+	       vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version);
+
+	pagevec_init(&pvec, 0);
+	first = 0;
+
+	for (;;) {
+		/* grab a bunch of pages to clean */
+		nr_pages = pagevec_lookup(&pvec, vnode->vfs_inode.i_mapping,
+					  first,
+					  PAGEVEC_SIZE - pagevec_count(&pvec));
+		if (!nr_pages)
+			break;
+
+		for (loop = 0; loop < nr_pages; loop++)
+			ClearPageFsCache(pvec.pages[loop]);
+
+		first = pvec.pages[nr_pages - 1]->index + 1;
+
+		pvec.nr = nr_pages;
+		pagevec_release(&pvec);
+		cond_resched();
+	}
+
+	_leave("");
+}