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![Al Viro](/assets/img/avatar_default.png)
pass inode + parent's inode or NULL instead of dentry + bool saying whether we want the parent or not. NOTE: that needs ceph fix folded in. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
220 lines
6.5 KiB
C
220 lines
6.5 KiB
C
/*
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* Cleancache frontend
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*
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* This code provides the generic "frontend" layer to call a matching
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* "backend" driver implementation of cleancache. See
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* Documentation/vm/cleancache.txt for more information.
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*
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* Copyright (C) 2009-2010 Oracle Corp. All rights reserved.
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* Author: Dan Magenheimer
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*
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* This work is licensed under the terms of the GNU GPL, version 2.
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/exportfs.h>
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#include <linux/mm.h>
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#include <linux/debugfs.h>
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#include <linux/cleancache.h>
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/*
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* This global enablement flag may be read thousands of times per second
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* by cleancache_get/put/invalidate even on systems where cleancache_ops
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* is not claimed (e.g. cleancache is config'ed on but remains
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* disabled), so is preferred to the slower alternative: a function
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* call that checks a non-global.
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*/
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int cleancache_enabled __read_mostly;
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EXPORT_SYMBOL(cleancache_enabled);
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/*
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* cleancache_ops is set by cleancache_ops_register to contain the pointers
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* to the cleancache "backend" implementation functions.
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*/
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static struct cleancache_ops cleancache_ops __read_mostly;
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/*
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* Counters available via /sys/kernel/debug/frontswap (if debugfs is
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* properly configured. These are for information only so are not protected
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* against increment races.
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*/
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static u64 cleancache_succ_gets;
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static u64 cleancache_failed_gets;
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static u64 cleancache_puts;
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static u64 cleancache_invalidates;
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/*
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* register operations for cleancache, returning previous thus allowing
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* detection of multiple backends and possible nesting
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*/
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struct cleancache_ops cleancache_register_ops(struct cleancache_ops *ops)
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{
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struct cleancache_ops old = cleancache_ops;
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cleancache_ops = *ops;
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cleancache_enabled = 1;
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return old;
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}
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EXPORT_SYMBOL(cleancache_register_ops);
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/* Called by a cleancache-enabled filesystem at time of mount */
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void __cleancache_init_fs(struct super_block *sb)
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{
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sb->cleancache_poolid = (*cleancache_ops.init_fs)(PAGE_SIZE);
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}
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EXPORT_SYMBOL(__cleancache_init_fs);
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/* Called by a cleancache-enabled clustered filesystem at time of mount */
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void __cleancache_init_shared_fs(char *uuid, struct super_block *sb)
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{
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sb->cleancache_poolid =
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(*cleancache_ops.init_shared_fs)(uuid, PAGE_SIZE);
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}
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EXPORT_SYMBOL(__cleancache_init_shared_fs);
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/*
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* If the filesystem uses exportable filehandles, use the filehandle as
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* the key, else use the inode number.
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*/
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static int cleancache_get_key(struct inode *inode,
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struct cleancache_filekey *key)
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{
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int (*fhfn)(struct inode *, __u32 *fh, int *, struct inode *);
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int len = 0, maxlen = CLEANCACHE_KEY_MAX;
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struct super_block *sb = inode->i_sb;
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key->u.ino = inode->i_ino;
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if (sb->s_export_op != NULL) {
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fhfn = sb->s_export_op->encode_fh;
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if (fhfn) {
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len = (*fhfn)(inode, &key->u.fh[0], &maxlen, NULL);
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if (len <= 0 || len == 255)
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return -1;
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if (maxlen > CLEANCACHE_KEY_MAX)
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return -1;
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}
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}
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return 0;
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}
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/*
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* "Get" data from cleancache associated with the poolid/inode/index
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* that were specified when the data was put to cleanache and, if
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* successful, use it to fill the specified page with data and return 0.
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* The pageframe is unchanged and returns -1 if the get fails.
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* Page must be locked by caller.
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*/
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int __cleancache_get_page(struct page *page)
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{
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int ret = -1;
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int pool_id;
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struct cleancache_filekey key = { .u.key = { 0 } };
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VM_BUG_ON(!PageLocked(page));
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pool_id = page->mapping->host->i_sb->cleancache_poolid;
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if (pool_id < 0)
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goto out;
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if (cleancache_get_key(page->mapping->host, &key) < 0)
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goto out;
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ret = (*cleancache_ops.get_page)(pool_id, key, page->index, page);
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if (ret == 0)
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cleancache_succ_gets++;
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else
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cleancache_failed_gets++;
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out:
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return ret;
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}
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EXPORT_SYMBOL(__cleancache_get_page);
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/*
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* "Put" data from a page to cleancache and associate it with the
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* (previously-obtained per-filesystem) poolid and the page's,
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* inode and page index. Page must be locked. Note that a put_page
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* always "succeeds", though a subsequent get_page may succeed or fail.
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*/
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void __cleancache_put_page(struct page *page)
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{
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int pool_id;
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struct cleancache_filekey key = { .u.key = { 0 } };
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VM_BUG_ON(!PageLocked(page));
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pool_id = page->mapping->host->i_sb->cleancache_poolid;
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if (pool_id >= 0 &&
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cleancache_get_key(page->mapping->host, &key) >= 0) {
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(*cleancache_ops.put_page)(pool_id, key, page->index, page);
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cleancache_puts++;
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}
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}
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EXPORT_SYMBOL(__cleancache_put_page);
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/*
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* Invalidate any data from cleancache associated with the poolid and the
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* page's inode and page index so that a subsequent "get" will fail.
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*/
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void __cleancache_invalidate_page(struct address_space *mapping,
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struct page *page)
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{
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/* careful... page->mapping is NULL sometimes when this is called */
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int pool_id = mapping->host->i_sb->cleancache_poolid;
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struct cleancache_filekey key = { .u.key = { 0 } };
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if (pool_id >= 0) {
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VM_BUG_ON(!PageLocked(page));
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if (cleancache_get_key(mapping->host, &key) >= 0) {
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(*cleancache_ops.invalidate_page)(pool_id,
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key, page->index);
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cleancache_invalidates++;
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}
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}
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}
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EXPORT_SYMBOL(__cleancache_invalidate_page);
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/*
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* Invalidate all data from cleancache associated with the poolid and the
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* mappings's inode so that all subsequent gets to this poolid/inode
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* will fail.
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*/
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void __cleancache_invalidate_inode(struct address_space *mapping)
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{
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int pool_id = mapping->host->i_sb->cleancache_poolid;
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struct cleancache_filekey key = { .u.key = { 0 } };
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if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0)
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(*cleancache_ops.invalidate_inode)(pool_id, key);
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}
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EXPORT_SYMBOL(__cleancache_invalidate_inode);
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/*
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* Called by any cleancache-enabled filesystem at time of unmount;
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* note that pool_id is surrendered and may be reutrned by a subsequent
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* cleancache_init_fs or cleancache_init_shared_fs
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*/
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void __cleancache_invalidate_fs(struct super_block *sb)
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{
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if (sb->cleancache_poolid >= 0) {
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int old_poolid = sb->cleancache_poolid;
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sb->cleancache_poolid = -1;
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(*cleancache_ops.invalidate_fs)(old_poolid);
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}
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}
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EXPORT_SYMBOL(__cleancache_invalidate_fs);
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static int __init init_cleancache(void)
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{
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#ifdef CONFIG_DEBUG_FS
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struct dentry *root = debugfs_create_dir("cleancache", NULL);
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if (root == NULL)
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return -ENXIO;
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debugfs_create_u64("succ_gets", S_IRUGO, root, &cleancache_succ_gets);
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debugfs_create_u64("failed_gets", S_IRUGO,
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root, &cleancache_failed_gets);
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debugfs_create_u64("puts", S_IRUGO, root, &cleancache_puts);
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debugfs_create_u64("invalidates", S_IRUGO,
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root, &cleancache_invalidates);
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#endif
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return 0;
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}
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module_init(init_cleancache)
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