Initial commit: OpenHarmony-v4.0-ReleaseOpenHarmony-v4.0-Release

1 files changed, 315 insertions, 0 deletions

diff --git a/mm/cleancache.c b/mm/cleancache.c
new file mode 100644
index 000000000..db7eee9c0
--- /dev/null
+++ b/mm/cleancache.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Cleancache frontend
+ *
+ * This code provides the generic "frontend" layer to call a matching
+ * "backend" driver implementation of cleancache.  See
+ * Documentation/vm/cleancache.rst for more information.
+ *
+ * Copyright (C) 2009-2010 Oracle Corp. All rights reserved.
+ * Author: Dan Magenheimer
+ */
+
+#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_register_ops to contain the pointers
+ * to the cleancache "backend" implementation functions.
+ */
+static const struct cleancache_ops *cleancache_ops __read_mostly;
+
+/*
+ * Counters available via /sys/kernel/debug/cleancache (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;
+
+static void cleancache_register_ops_sb(struct super_block *sb, void *unused)
+{
+        switch (sb->cleancache_poolid) {
+        case CLEANCACHE_NO_BACKEND:
+                __cleancache_init_fs(sb);
+                break;
+        case CLEANCACHE_NO_BACKEND_SHARED:
+                __cleancache_init_shared_fs(sb);
+                break;
+        }
+}
+
+/*
+ * Register operations for cleancache. Returns 0 on success.
+ */
+int cleancache_register_ops(const struct cleancache_ops *ops)
+{
+        if (cmpxchg(&cleancache_ops, NULL, ops))
+                return -EBUSY;
+
+        /*
+         * A cleancache backend can be built as a module and hence loaded after
+         * a cleancache enabled filesystem has called cleancache_init_fs. To
+         * handle such a scenario, here we call ->init_fs or ->init_shared_fs
+         * for each active super block. To differentiate between local and
+         * shared filesystems, we temporarily initialize sb->cleancache_poolid
+         * to CLEANCACHE_NO_BACKEND or CLEANCACHE_NO_BACKEND_SHARED
+         * respectively in case there is no backend registered at the time
+         * cleancache_init_fs or cleancache_init_shared_fs is called.
+         *
+         * Since filesystems can be mounted concurrently with cleancache
+         * backend registration, we have to be careful to guarantee that all
+         * cleancache enabled filesystems that has been mounted by the time
+         * cleancache_register_ops is called has got and all mounted later will
+         * get cleancache_poolid. This is assured by the following statements
+         * tied together:
+         *
+         * a) iterate_supers skips only those super blocks that has started
+         *    ->kill_sb
+         *
+         * b) if iterate_supers encounters a super block that has not finished
+         *    ->mount yet, it waits until it is finished
+         *
+         * c) cleancache_init_fs is called from ->mount and
+         *    cleancache_invalidate_fs is called from ->kill_sb
+         *
+         * d) we call iterate_supers after cleancache_ops has been set
+         *
+         * From a) it follows that if iterate_supers skips a super block, then
+         * either the super block is already dead, in which case we do not need
+         * to bother initializing cleancache for it, or it was mounted after we
+         * initiated iterate_supers. In the latter case, it must have seen
+         * cleancache_ops set according to d) and initialized cleancache from
+         * ->mount by itself according to c). This proves that we call
+         * ->init_fs at least once for each active super block.
+         *
+         * From b) and c) it follows that if iterate_supers encounters a super
+         * block that has already started ->init_fs, it will wait until ->mount
+         * and hence ->init_fs has finished, then check cleancache_poolid, see
+         * that it has already been set and therefore do nothing. This proves
+         * that we call ->init_fs no more than once for each super block.
+         *
+         * Combined together, the last two paragraphs prove the function
+         * correctness.
+         *
+         * Note that various cleancache callbacks may proceed before this
+         * function is called or even concurrently with it, but since
+         * CLEANCACHE_NO_BACKEND is negative, they will all result in a noop
+         * until the corresponding ->init_fs has been actually called and
+         * cleancache_ops has been set.
+         */
+        iterate_supers(cleancache_register_ops_sb, NULL);
+        return 0;
+}
+EXPORT_SYMBOL(cleancache_register_ops);
+
+/* Called by a cleancache-enabled filesystem at time of mount */
+void __cleancache_init_fs(struct super_block *sb)
+{
+        int pool_id = CLEANCACHE_NO_BACKEND;
+
+        if (cleancache_ops) {
+                pool_id = cleancache_ops->init_fs(PAGE_SIZE);
+                if (pool_id < 0)
+                        pool_id = CLEANCACHE_NO_POOL;
+        }
+        sb->cleancache_poolid = pool_id;
+}
+EXPORT_SYMBOL(__cleancache_init_fs);
+
+/* Called by a cleancache-enabled clustered filesystem at time of mount */
+void __cleancache_init_shared_fs(struct super_block *sb)
+{
+        int pool_id = CLEANCACHE_NO_BACKEND_SHARED;
+
+        if (cleancache_ops) {
+                pool_id = cleancache_ops->init_shared_fs(&sb->s_uuid, PAGE_SIZE);
+                if (pool_id < 0)
+                        pool_id = CLEANCACHE_NO_POOL;
+        }
+        sb->cleancache_poolid = pool_id;
+}
+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;
+}
+
+/*
+ * "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;
+        struct cleancache_filekey key = { .u.key = { 0 } };
+
+        if (!cleancache_ops) {
+                cleancache_failed_gets++;
+                goto out;
+        }
+
+        VM_BUG_ON_PAGE(!PageLocked(page), 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.
+ *
+ * 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;
+        struct cleancache_filekey key = { .u.key = { 0 } };
+
+        if (!cleancache_ops) {
+                cleancache_puts++;
+                return;
+        }
+
+        VM_BUG_ON_PAGE(!PageLocked(page), 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);
+
+/*
+ * 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 = mapping->host->i_sb->cleancache_poolid;
+        struct cleancache_filekey key = { .u.key = { 0 } };
+
+        if (!cleancache_ops)
+                return;
+
+        if (pool_id >= 0) {
+                VM_BUG_ON_PAGE(!PageLocked(page), 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 = mapping->host->i_sb->cleancache_poolid;
+        struct cleancache_filekey key = { .u.key = { 0 } };
+
+        if (!cleancache_ops)
+                return;
+
+        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 pool_id;
+
+        pool_id = sb->cleancache_poolid;
+        sb->cleancache_poolid = CLEANCACHE_NO_POOL;
+
+        if (cleancache_ops && pool_id >= 0)
+                cleancache_ops->invalidate_fs(pool_id);
+}
+EXPORT_SYMBOL(__cleancache_invalidate_fs);
+
+static int __init init_cleancache(void)
+{
+#ifdef CONFIG_DEBUG_FS
+        struct dentry *root = debugfs_create_dir("cleancache", NULL);
+
+        debugfs_create_u64("succ_gets", 0444, root, &cleancache_succ_gets);
+        debugfs_create_u64("failed_gets", 0444, root, &cleancache_failed_gets);
+        debugfs_create_u64("puts", 0444, root, &cleancache_puts);
+        debugfs_create_u64("invalidates", 0444, root, &cleancache_invalidates);
+#endif
+        return 0;
+}
+module_init(init_cleancache)