1 files changed, 0 insertions, 409 deletions
diff --git a/mm/cleancache.c b/mm/cleancache.c
deleted file mode 100644
index 5875f48ce279..000000000000
--- a/mm/cleancache.c
+++ /dev/null
@@ -1,409 +0,0 @@
-/*
- * 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/debugfs.h>
-#include <linux/cleancache.h>
-
-/*
- * cleancache_ops is set by cleancache_ops_register to contain the pointers
- * to the cleancache "backend" implementation functions.
- */
-static struct cleancache_ops *cleancache_ops __read_mostly;
-
-/*
- * Counters available via /sys/kernel/debug/frontswap (if debugfs is
- * properly configured.  These are for information only so are not protected
- * against increment races.
- */
-static u64 cleancache_succ_gets;
-static u64 cleancache_failed_gets;
-static u64 cleancache_puts;
-static u64 cleancache_invalidates;
-
-/*
- * When no backend is registered all calls to init_fs and init_shared_fs
- * are registered and fake poolids (FAKE_FS_POOLID_OFFSET or
- * FAKE_SHARED_FS_POOLID_OFFSET, plus offset in the respective array
- * [shared_|]fs_poolid_map) are given to the respective super block
- * (sb->cleancache_poolid) and no tmem_pools are created. When a backend
- * registers with cleancache the previous calls to init_fs and init_shared_fs
- * are executed to create tmem_pools and set the respective poolids. While no
- * backend is registered all "puts", "gets" and "flushes" are ignored or failed.
- */
-#define MAX_INITIALIZABLE_FS 32
-#define FAKE_FS_POOLID_OFFSET 1000
-#define FAKE_SHARED_FS_POOLID_OFFSET 2000
-
-#define FS_NO_BACKEND (-1)
-#define FS_UNKNOWN (-2)
-static int fs_poolid_map[MAX_INITIALIZABLE_FS];
-static int shared_fs_poolid_map[MAX_INITIALIZABLE_FS];
-static char *uuids[MAX_INITIALIZABLE_FS];
-/*
- * Mutex for the [shared_|]fs_poolid_map to guard against multiple threads
- * invoking umount (and ending in __cleancache_invalidate_fs) and also multiple
- * threads calling mount (and ending up in __cleancache_init_[shared|]fs).
- */
-static DEFINE_MUTEX(poolid_mutex);
-/*
- * When set to false (default) all calls to the cleancache functions, except
- * the __cleancache_invalidate_fs and __cleancache_init_[shared|]fs are guarded
- * by the if (!cleancache_ops) return. This means multiple threads (from
- * different filesystems) will be checking cleancache_ops. The usage of a
- * bool instead of a atomic_t or a bool guarded by a spinlock is OK - we are
- * OK if the time between the backend's have been initialized (and
- * cleancache_ops has been set to not NULL) and when the filesystems start
- * actually calling the backends. The inverse (when unloading) is obviously
- * not good - but this shim does not do that (yet).
- */
-
-/*
- * The backends and filesystems work all asynchronously. This is b/c the
- * backends can be built as modules.
- * The usual sequence of events is:
- *	a) mount /	-> __cleancache_init_fs is called. We set the
- *		[shared_|]fs_poolid_map and uuids for.
- *
- *	b). user does I/Os -> we call the rest of __cleancache_* functions
- *		which return immediately as cleancache_ops is false.
- *
- *	c). modprobe zcache -> cleancache_register_ops. We init the backend
- *		and set cleancache_ops to true, and for any fs_poolid_map
- *		(which is set by __cleancache_init_fs) we initialize the poolid.
- *
- *	d). user does I/Os -> now that cleancache_ops is true all the
- *		__cleancache_* functions can call the backend. They all check
- *		that fs_poolid_map is valid and if so invoke the backend.
- *
- *	e). umount /	-> __cleancache_invalidate_fs, the fs_poolid_map is
- *		reset (which is the second check in the __cleancache_* ops
- *		to call the backend).
- *
- * The sequence of event could also be c), followed by a), and d). and e). The
- * c) would not happen anymore. There is also the chance of c), and one thread
- * doing a) + d), and another doing e). For that case we depend on the
- * filesystem calling __cleancache_invalidate_fs in the proper sequence (so
- * that it handles all I/Os before it invalidates the fs (which is last part
- * of unmounting process).
- *
- * Note: The acute reader will notice that there is no "rmmod zcache" case.
- * This is b/c the functionality for that is not yet implemented and when
- * done, will require some extra locking not yet devised.
- */
-
-/*
- * 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;
-	int i;
-
-	mutex_lock(&poolid_mutex);
-	for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
-		if (fs_poolid_map[i] == FS_NO_BACKEND)
-			fs_poolid_map[i] = ops->init_fs(PAGE_SIZE);
-		if (shared_fs_poolid_map[i] == FS_NO_BACKEND)
-			shared_fs_poolid_map[i] = ops->init_shared_fs
-					(uuids[i], PAGE_SIZE);
-	}
-	/*
-	 * We MUST set cleancache_ops _after_ we have called the backends
-	 * init_fs or init_shared_fs functions. Otherwise the compiler might
-	 * re-order where cleancache_ops is set in this function.
-	 */
-	barrier();
-	cleancache_ops = ops;
-	mutex_unlock(&poolid_mutex);
-	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)
-{
-	int i;
-
-	mutex_lock(&poolid_mutex);
-	for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
-		if (fs_poolid_map[i] == FS_UNKNOWN) {
-			sb->cleancache_poolid = i + FAKE_FS_POOLID_OFFSET;
-			if (cleancache_ops)
-				fs_poolid_map[i] = cleancache_ops->init_fs(PAGE_SIZE);
-			else
-				fs_poolid_map[i] = FS_NO_BACKEND;
-			break;
-		}
-	}
-	mutex_unlock(&poolid_mutex);
-}
-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)
-{
-	int i;
-
-	mutex_lock(&poolid_mutex);
-	for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
-		if (shared_fs_poolid_map[i] == FS_UNKNOWN) {
-			sb->cleancache_poolid = i + FAKE_SHARED_FS_POOLID_OFFSET;
-			uuids[i] = uuid;
-			if (cleancache_ops)
-				shared_fs_poolid_map[i] = cleancache_ops->init_shared_fs
-						(uuid, PAGE_SIZE);
-			else
-				shared_fs_poolid_map[i] = FS_NO_BACKEND;
-			break;
-		}
-	}
-	mutex_unlock(&poolid_mutex);
-}
-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 inode *, __u32 *fh, int *, struct inode *);
-	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) {
-			len = (*fhfn)(inode, &key->u.fh[0], &maxlen, NULL);
-			if (len <= FILEID_ROOT || len == FILEID_INVALID)
-				return -1;
-			if (maxlen > CLEANCACHE_KEY_MAX)
-				return -1;
-		}
-	}
-	return 0;
-}
-
-/*
- * Returns a pool_id that is associated with a given fake poolid.
- */
-static int get_poolid_from_fake(int fake_pool_id)
-{
-	if (fake_pool_id >= FAKE_SHARED_FS_POOLID_OFFSET)
-		return shared_fs_poolid_map[fake_pool_id -
-			FAKE_SHARED_FS_POOLID_OFFSET];
-	else if (fake_pool_id >= FAKE_FS_POOLID_OFFSET)
-		return fs_poolid_map[fake_pool_id - FAKE_FS_POOLID_OFFSET];
-	return FS_NO_BACKEND;
-}
-
-/*
- * "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.
- *
- * The function has two checks before any action is taken - whether
- * a backend is registered and whether the sb->cleancache_poolid
- * is correct.
- */
-int __cleancache_get_page(struct page *page)
-{
-	int ret = -1;
-	int pool_id;
-	int fake_pool_id;
-	struct cleancache_filekey key = { .u.key = { 0 } };
-
-	if (!cleancache_ops) {
-		cleancache_failed_gets++;
-		goto out;
-	}
-
-	VM_BUG_ON(!PageLocked(page));
-	fake_pool_id = page->mapping->host->i_sb->cleancache_poolid;
-	if (fake_pool_id < 0)
-		goto out;
-	pool_id = get_poolid_from_fake(fake_pool_id);
-
-	if (cleancache_get_key(page->mapping->host, &key) < 0)
-		goto out;
-
-	if (pool_id >= 0)
-		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.
- *
- * The function has two checks before any action is taken - whether
- * a backend is registered and whether the sb->cleancache_poolid
- * is correct.
- */
-void __cleancache_put_page(struct page *page)
-{
-	int pool_id;
-	int fake_pool_id;
-	struct cleancache_filekey key = { .u.key = { 0 } };
-
-	if (!cleancache_ops) {
-		cleancache_puts++;
-		return;
-	}
-
-	VM_BUG_ON(!PageLocked(page));
-	fake_pool_id = page->mapping->host->i_sb->cleancache_poolid;
-	if (fake_pool_id < 0)
-		return;
-
-	pool_id = get_poolid_from_fake(fake_pool_id);
-
-	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);
-
-/*
- * Invalidate any data from cleancache associated with the poolid and the
- * page's inode and page index so that a subsequent "get" will fail.
- *
- * The function has two checks before any action is taken - whether
- * a backend is registered and whether the sb->cleancache_poolid
- * is correct.
- */
-void __cleancache_invalidate_page(struct address_space *mapping,
-					struct page *page)
-{
-	/* careful... page->mapping is NULL sometimes when this is called */
-	int pool_id;
-	int fake_pool_id = mapping->host->i_sb->cleancache_poolid;
-	struct cleancache_filekey key = { .u.key = { 0 } };
-
-	if (!cleancache_ops)
-		return;
-
-	if (fake_pool_id >= 0) {
-		pool_id = get_poolid_from_fake(fake_pool_id);
-		if (pool_id < 0)
-			return;
-
-		VM_BUG_ON(!PageLocked(page));
-		if (cleancache_get_key(mapping->host, &key) >= 0) {
-			cleancache_ops->invalidate_page(pool_id,
-					key, page->index);
-			cleancache_invalidates++;
-		}
-	}
-}
-EXPORT_SYMBOL(__cleancache_invalidate_page);
-
-/*
- * Invalidate all data from cleancache associated with the poolid and the
- * mappings's inode so that all subsequent gets to this poolid/inode
- * will fail.
- *
- * The function has two checks before any action is taken - whether
- * a backend is registered and whether the sb->cleancache_poolid
- * is correct.
- */
-void __cleancache_invalidate_inode(struct address_space *mapping)
-{
-	int pool_id;
-	int fake_pool_id = mapping->host->i_sb->cleancache_poolid;
-	struct cleancache_filekey key = { .u.key = { 0 } };
-
-	if (!cleancache_ops)
-		return;
-
-	if (fake_pool_id < 0)
-		return;
-
-	pool_id = get_poolid_from_fake(fake_pool_id);
-
-	if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0)
-		cleancache_ops->invalidate_inode(pool_id, key);
-}
-EXPORT_SYMBOL(__cleancache_invalidate_inode);
-
-/*
- * Called by any cleancache-enabled filesystem at time of unmount;
- * note that pool_id is surrendered and may be returned by a subsequent
- * cleancache_init_fs or cleancache_init_shared_fs.
- */
-void __cleancache_invalidate_fs(struct super_block *sb)
-{
-	int index;
-	int fake_pool_id = sb->cleancache_poolid;
-	int old_poolid = fake_pool_id;
-
-	mutex_lock(&poolid_mutex);
-	if (fake_pool_id >= FAKE_SHARED_FS_POOLID_OFFSET) {
-		index = fake_pool_id - FAKE_SHARED_FS_POOLID_OFFSET;
-		old_poolid = shared_fs_poolid_map[index];
-		shared_fs_poolid_map[index] = FS_UNKNOWN;
-		uuids[index] = NULL;
-	} else if (fake_pool_id >= FAKE_FS_POOLID_OFFSET) {
-		index = fake_pool_id - FAKE_FS_POOLID_OFFSET;
-		old_poolid = fs_poolid_map[index];
-		fs_poolid_map[index] = FS_UNKNOWN;
-	}
-	sb->cleancache_poolid = -1;
-	if (cleancache_ops)
-		cleancache_ops->invalidate_fs(old_poolid);
-	mutex_unlock(&poolid_mutex);
-}
-EXPORT_SYMBOL(__cleancache_invalidate_fs);
-
-static int __init init_cleancache(void)
-{
-	int i;
-
-#ifdef CONFIG_DEBUG_FS
-	struct dentry *root = debugfs_create_dir("cleancache", NULL);
-	if (root == NULL)
-		return -ENXIO;
-	debugfs_create_u64("succ_gets", S_IRUGO, root, &cleancache_succ_gets);
-	debugfs_create_u64("failed_gets", S_IRUGO,
-				root, &cleancache_failed_gets);
-	debugfs_create_u64("puts", S_IRUGO, root, &cleancache_puts);
-	debugfs_create_u64("invalidates", S_IRUGO,
-				root, &cleancache_invalidates);
-#endif
-	for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
-		fs_poolid_map[i] = FS_UNKNOWN;
-		shared_fs_poolid_map[i] = FS_UNKNOWN;
-	}
-	return 0;
-}
-module_init(init_cleancache)