mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
245 lines
6.9 KiB
C
245 lines
6.9 KiB
C
![]() |
/*
|
||
|
* Cleancache frontend
|
||
|
*
|
||
|
* This code provides the generic "frontend" layer to call a matching
|
||
|
* "backend" driver implementation of cleancache. See
|
||
|
* Documentation/vm/cleancache.txt for more information.
|
||
|
*
|
||
|
* Copyright (C) 2009-2010 Oracle Corp. All rights reserved.
|
||
|
* Author: Dan Magenheimer
|
||
|
*
|
||
|
* This work is licensed under the terms of the GNU GPL, version 2.
|
||
|
*/
|
||
|
|
||
|
#include <linux/module.h>
|
||
|
#include <linux/fs.h>
|
||
|
#include <linux/exportfs.h>
|
||
|
#include <linux/mm.h>
|
||
|
#include <linux/cleancache.h>
|
||
|
|
||
|
/*
|
||
|
* This global enablement flag may be read thousands of times per second
|
||
|
* by cleancache_get/put/flush even on systems where cleancache_ops
|
||
|
* is not claimed (e.g. cleancache is config'ed on but remains
|
||
|
* disabled), so is preferred to the slower alternative: a function
|
||
|
* call that checks a non-global.
|
||
|
*/
|
||
|
int cleancache_enabled;
|
||
|
EXPORT_SYMBOL(cleancache_enabled);
|
||
|
|
||
|
/*
|
||
|
* cleancache_ops is set by cleancache_ops_register to contain the pointers
|
||
|
* to the cleancache "backend" implementation functions.
|
||
|
*/
|
||
|
static struct cleancache_ops cleancache_ops;
|
||
|
|
||
|
/* useful stats available in /sys/kernel/mm/cleancache */
|
||
|
static unsigned long cleancache_succ_gets;
|
||
|
static unsigned long cleancache_failed_gets;
|
||
|
static unsigned long cleancache_puts;
|
||
|
static unsigned long cleancache_flushes;
|
||
|
|
||
|
/*
|
||
|
* register operations for cleancache, returning previous thus allowing
|
||
|
* detection of multiple backends and possible nesting
|
||
|
*/
|
||
|
struct cleancache_ops cleancache_register_ops(struct cleancache_ops *ops)
|
||
|
{
|
||
|
struct cleancache_ops old = cleancache_ops;
|
||
|
|
||
|
cleancache_ops = *ops;
|
||
|
cleancache_enabled = 1;
|
||
|
return old;
|
||
|
}
|
||
|
EXPORT_SYMBOL(cleancache_register_ops);
|
||
|
|
||
|
/* Called by a cleancache-enabled filesystem at time of mount */
|
||
|
void __cleancache_init_fs(struct super_block *sb)
|
||
|
{
|
||
|
sb->cleancache_poolid = (*cleancache_ops.init_fs)(PAGE_SIZE);
|
||
|
}
|
||
|
EXPORT_SYMBOL(__cleancache_init_fs);
|
||
|
|
||
|
/* Called by a cleancache-enabled clustered filesystem at time of mount */
|
||
|
void __cleancache_init_shared_fs(char *uuid, struct super_block *sb)
|
||
|
{
|
||
|
sb->cleancache_poolid =
|
||
|
(*cleancache_ops.init_shared_fs)(uuid, PAGE_SIZE);
|
||
|
}
|
||
|
EXPORT_SYMBOL(__cleancache_init_shared_fs);
|
||
|
|
||
|
/*
|
||
|
* If the filesystem uses exportable filehandles, use the filehandle as
|
||
|
* the key, else use the inode number.
|
||
|
*/
|
||
|
static int cleancache_get_key(struct inode *inode,
|
||
|
struct cleancache_filekey *key)
|
||
|
{
|
||
|
int (*fhfn)(struct dentry *, __u32 *fh, int *, int);
|
||
|
int len = 0, maxlen = CLEANCACHE_KEY_MAX;
|
||
|
struct super_block *sb = inode->i_sb;
|
||
|
|
||
|
key->u.ino = inode->i_ino;
|
||
|
if (sb->s_export_op != NULL) {
|
||
|
fhfn = sb->s_export_op->encode_fh;
|
||
|
if (fhfn) {
|
||
|
struct dentry d;
|
||
|
d.d_inode = inode;
|
||
|
len = (*fhfn)(&d, &key->u.fh[0], &maxlen, 0);
|
||
|
if (len <= 0 || len == 255)
|
||
|
return -1;
|
||
|
if (maxlen > CLEANCACHE_KEY_MAX)
|
||
|
return -1;
|
||
|
}
|
||
|
}
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* "Get" data from cleancache associated with the poolid/inode/index
|
||
|
* that were specified when the data was put to cleanache and, if
|
||
|
* successful, use it to fill the specified page with data and return 0.
|
||
|
* The pageframe is unchanged and returns -1 if the get fails.
|
||
|
* Page must be locked by caller.
|
||
|
*/
|
||
|
int __cleancache_get_page(struct page *page)
|
||
|
{
|
||
|
int ret = -1;
|
||
|
int pool_id;
|
||
|
struct cleancache_filekey key = { .u.key = { 0 } };
|
||
|
|
||
|
VM_BUG_ON(!PageLocked(page));
|
||
|
pool_id = page->mapping->host->i_sb->cleancache_poolid;
|
||
|
if (pool_id < 0)
|
||
|
goto out;
|
||
|
|
||
|
if (cleancache_get_key(page->mapping->host, &key) < 0)
|
||
|
goto out;
|
||
|
|
||
|
ret = (*cleancache_ops.get_page)(pool_id, key, page->index, page);
|
||
|
if (ret == 0)
|
||
|
cleancache_succ_gets++;
|
||
|
else
|
||
|
cleancache_failed_gets++;
|
||
|
out:
|
||
|
return ret;
|
||
|
}
|
||
|
EXPORT_SYMBOL(__cleancache_get_page);
|
||
|
|
||
|
/*
|
||
|
* "Put" data from a page to cleancache and associate it with the
|
||
|
* (previously-obtained per-filesystem) poolid and the page's,
|
||
|
* inode and page index. Page must be locked. Note that a put_page
|
||
|
* always "succeeds", though a subsequent get_page may succeed or fail.
|
||
|
*/
|
||
|
void __cleancache_put_page(struct page *page)
|
||
|
{
|
||
|
int pool_id;
|
||
|
struct cleancache_filekey key = { .u.key = { 0 } };
|
||
|
|
||
|
VM_BUG_ON(!PageLocked(page));
|
||
|
pool_id = page->mapping->host->i_sb->cleancache_poolid;
|
||
|
if (pool_id >= 0 &&
|
||
|
cleancache_get_key(page->mapping->host, &key) >= 0) {
|
||
|
(*cleancache_ops.put_page)(pool_id, key, page->index, page);
|
||
|
cleancache_puts++;
|
||
|
}
|
||
|
}
|
||
|
EXPORT_SYMBOL(__cleancache_put_page);
|
||
|
|
||
|
/*
|
||
|
* Flush any data from cleancache associated with the poolid and the
|
||
|
* page's inode and page index so that a subsequent "get" will fail.
|
||
|
*/
|
||
|
void __cleancache_flush_page(struct address_space *mapping, struct page *page)
|
||
|
{
|
||
|
/* careful... page->mapping is NULL sometimes when this is called */
|
||
|
int pool_id = mapping->host->i_sb->cleancache_poolid;
|
||
|
struct cleancache_filekey key = { .u.key = { 0 } };
|
||
|
|
||
|
if (pool_id >= 0) {
|
||
|
VM_BUG_ON(!PageLocked(page));
|
||
|
if (cleancache_get_key(mapping->host, &key) >= 0) {
|
||
|
(*cleancache_ops.flush_page)(pool_id, key, page->index);
|
||
|
cleancache_flushes++;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
EXPORT_SYMBOL(__cleancache_flush_page);
|
||
|
|
||
|
/*
|
||
|
* Flush all data from cleancache associated with the poolid and the
|
||
|
* mappings's inode so that all subsequent gets to this poolid/inode
|
||
|
* will fail.
|
||
|
*/
|
||
|
void __cleancache_flush_inode(struct address_space *mapping)
|
||
|
{
|
||
|
int pool_id = mapping->host->i_sb->cleancache_poolid;
|
||
|
struct cleancache_filekey key = { .u.key = { 0 } };
|
||
|
|
||
|
if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0)
|
||
|
(*cleancache_ops.flush_inode)(pool_id, key);
|
||
|
}
|
||
|
EXPORT_SYMBOL(__cleancache_flush_inode);
|
||
|
|
||
|
/*
|
||
|
* Called by any cleancache-enabled filesystem at time of unmount;
|
||
|
* note that pool_id is surrendered and may be reutrned by a subsequent
|
||
|
* cleancache_init_fs or cleancache_init_shared_fs
|
||
|
*/
|
||
|
void __cleancache_flush_fs(struct super_block *sb)
|
||
|
{
|
||
|
if (sb->cleancache_poolid >= 0) {
|
||
|
int old_poolid = sb->cleancache_poolid;
|
||
|
sb->cleancache_poolid = -1;
|
||
|
(*cleancache_ops.flush_fs)(old_poolid);
|
||
|
}
|
||
|
}
|
||
|
EXPORT_SYMBOL(__cleancache_flush_fs);
|
||
|
|
||
|
#ifdef CONFIG_SYSFS
|
||
|
|
||
|
/* see Documentation/ABI/xxx/sysfs-kernel-mm-cleancache */
|
||
|
|
||
|
#define CLEANCACHE_SYSFS_RO(_name) \
|
||
|
static ssize_t cleancache_##_name##_show(struct kobject *kobj, \
|
||
|
struct kobj_attribute *attr, char *buf) \
|
||
|
{ \
|
||
|
return sprintf(buf, "%lu\n", cleancache_##_name); \
|
||
|
} \
|
||
|
static struct kobj_attribute cleancache_##_name##_attr = { \
|
||
|
.attr = { .name = __stringify(_name), .mode = 0444 }, \
|
||
|
.show = cleancache_##_name##_show, \
|
||
|
}
|
||
|
|
||
|
CLEANCACHE_SYSFS_RO(succ_gets);
|
||
|
CLEANCACHE_SYSFS_RO(failed_gets);
|
||
|
CLEANCACHE_SYSFS_RO(puts);
|
||
|
CLEANCACHE_SYSFS_RO(flushes);
|
||
|
|
||
|
static struct attribute *cleancache_attrs[] = {
|
||
|
&cleancache_succ_gets_attr.attr,
|
||
|
&cleancache_failed_gets_attr.attr,
|
||
|
&cleancache_puts_attr.attr,
|
||
|
&cleancache_flushes_attr.attr,
|
||
|
NULL,
|
||
|
};
|
||
|
|
||
|
static struct attribute_group cleancache_attr_group = {
|
||
|
.attrs = cleancache_attrs,
|
||
|
.name = "cleancache",
|
||
|
};
|
||
|
|
||
|
#endif /* CONFIG_SYSFS */
|
||
|
|
||
|
static int __init init_cleancache(void)
|
||
|
{
|
||
|
#ifdef CONFIG_SYSFS
|
||
|
int err;
|
||
|
|
||
|
err = sysfs_create_group(mm_kobj, &cleancache_attr_group);
|
||
|
#endif /* CONFIG_SYSFS */
|
||
|
return 0;
|
||
|
}
|
||
|
module_init(init_cleancache)
|