1 files changed, 286 insertions, 0 deletions

diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c
new file mode 100644
index 000000000000..3797e0077b35
--- /dev/null
+++ b/fs/cachefiles/bind.c
@@ -0,0 +1,286 @@
+/* Bind and unbind a cache from the filesystem backing it
+ *
+ * Copyright (C) 2007 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 Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/statfs.h>
+#include <linux/ctype.h>
+#include "internal.h"
+
+static int cachefiles_daemon_add_cache(struct cachefiles_cache *caches);
+
+/*
+ * bind a directory as a cache
+ */
+int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
+{
+        _enter("{%u,%u,%u,%u,%u,%u},%s",
+               cache->frun_percent,
+               cache->fcull_percent,
+               cache->fstop_percent,
+               cache->brun_percent,
+               cache->bcull_percent,
+               cache->bstop_percent,
+               args);
+
+        /* start by checking things over */
+        ASSERT(cache->fstop_percent >= 0 &&
+               cache->fstop_percent < cache->fcull_percent &&
+               cache->fcull_percent < cache->frun_percent &&
+               cache->frun_percent  < 100);
+
+        ASSERT(cache->bstop_percent >= 0 &&
+               cache->bstop_percent < cache->bcull_percent &&
+               cache->bcull_percent < cache->brun_percent &&
+               cache->brun_percent  < 100);
+
+        if (*args) {
+                kerror("'bind' command doesn't take an argument");
+                return -EINVAL;
+        }
+
+        if (!cache->rootdirname) {
+                kerror("No cache directory specified");
+                return -EINVAL;
+        }
+
+        /* don't permit already bound caches to be re-bound */
+        if (test_bit(CACHEFILES_READY, &cache->flags)) {
+                kerror("Cache already bound");
+                return -EBUSY;
+        }
+
+        /* make sure we have copies of the tag and dirname strings */
+        if (!cache->tag) {
+                /* the tag string is released by the fops->release()
+                 * function, so we don't release it on error here */
+                cache->tag = kstrdup("CacheFiles", GFP_KERNEL);
+                if (!cache->tag)
+                        return -ENOMEM;
+        }
+
+        /* add the cache */
+        return cachefiles_daemon_add_cache(cache);
+}
+
+/*
+ * add a cache
+ */
+static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache)
+{
+        struct cachefiles_object *fsdef;
+        struct nameidata nd;
+        struct kstatfs stats;
+        struct dentry *graveyard, *cachedir, *root;
+        const struct cred *saved_cred;
+        int ret;
+
+        _enter("");
+
+        /* we want to work under the module's security ID */
+        ret = cachefiles_get_security_ID(cache);
+        if (ret < 0)
+                return ret;
+
+        cachefiles_begin_secure(cache, &saved_cred);
+
+        /* allocate the root index object */
+        ret = -ENOMEM;
+
+        fsdef = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
+        if (!fsdef)
+                goto error_root_object;
+
+        ASSERTCMP(fsdef->backer, ==, NULL);
+
+        atomic_set(&fsdef->usage, 1);
+        fsdef->type = FSCACHE_COOKIE_TYPE_INDEX;
+
+        _debug("- fsdef %p", fsdef);
+
+        /* look up the directory at the root of the cache */
+        memset(&nd, 0, sizeof(nd));
+
+        ret = path_lookup(cache->rootdirname, LOOKUP_DIRECTORY, &nd);
+        if (ret < 0)
+                goto error_open_root;
+
+        cache->mnt = mntget(nd.path.mnt);
+        root = dget(nd.path.dentry);
+        path_put(&nd.path);
+
+        /* check parameters */
+        ret = -EOPNOTSUPP;
+        if (!root->d_inode ||
+            !root->d_inode->i_op ||
+            !root->d_inode->i_op->lookup ||
+            !root->d_inode->i_op->mkdir ||
+            !root->d_inode->i_op->setxattr ||
+            !root->d_inode->i_op->getxattr ||
+            !root->d_sb ||
+            !root->d_sb->s_op ||
+            !root->d_sb->s_op->statfs ||
+            !root->d_sb->s_op->sync_fs)
+                goto error_unsupported;
+
+        ret = -EROFS;
+        if (root->d_sb->s_flags & MS_RDONLY)
+                goto error_unsupported;
+
+        /* determine the security of the on-disk cache as this governs
+         * security ID of files we create */
+        ret = cachefiles_determine_cache_security(cache, root, &saved_cred);
+        if (ret < 0)
+                goto error_unsupported;
+
+        /* get the cache size and blocksize */
+        ret = vfs_statfs(root, &stats);
+        if (ret < 0)
+                goto error_unsupported;
+
+        ret = -ERANGE;
+        if (stats.f_bsize <= 0)
+                goto error_unsupported;
+
+        ret = -EOPNOTSUPP;
+        if (stats.f_bsize > PAGE_SIZE)
+                goto error_unsupported;
+
+        cache->bsize = stats.f_bsize;
+        cache->bshift = 0;
+        if (stats.f_bsize < PAGE_SIZE)
+                cache->bshift = PAGE_SHIFT - ilog2(stats.f_bsize);
+
+        _debug("blksize %u (shift %u)",
+               cache->bsize, cache->bshift);
+
+        _debug("size %llu, avail %llu",
+               (unsigned long long) stats.f_blocks,
+               (unsigned long long) stats.f_bavail);
+
+        /* set up caching limits */
+        do_div(stats.f_files, 100);
+        cache->fstop = stats.f_files * cache->fstop_percent;
+        cache->fcull = stats.f_files * cache->fcull_percent;
+        cache->frun  = stats.f_files * cache->frun_percent;
+
+        _debug("limits {%llu,%llu,%llu} files",
+               (unsigned long long) cache->frun,
+               (unsigned long long) cache->fcull,
+               (unsigned long long) cache->fstop);
+
+        stats.f_blocks >>= cache->bshift;
+        do_div(stats.f_blocks, 100);
+        cache->bstop = stats.f_blocks * cache->bstop_percent;
+        cache->bcull = stats.f_blocks * cache->bcull_percent;
+        cache->brun  = stats.f_blocks * cache->brun_percent;
+
+        _debug("limits {%llu,%llu,%llu} blocks",
+               (unsigned long long) cache->brun,
+               (unsigned long long) cache->bcull,
+               (unsigned long long) cache->bstop);
+
+        /* get the cache directory and check its type */
+        cachedir = cachefiles_get_directory(cache, root, "cache");
+        if (IS_ERR(cachedir)) {
+                ret = PTR_ERR(cachedir);
+                goto error_unsupported;
+        }
+
+        fsdef->dentry = cachedir;
+        fsdef->fscache.cookie = NULL;
+
+        ret = cachefiles_check_object_type(fsdef);
+        if (ret < 0)
+                goto error_unsupported;
+
+        /* get the graveyard directory */
+        graveyard = cachefiles_get_directory(cache, root, "graveyard");
+        if (IS_ERR(graveyard)) {
+                ret = PTR_ERR(graveyard);
+                goto error_unsupported;
+        }
+
+        cache->graveyard = graveyard;
+
+        /* publish the cache */
+        fscache_init_cache(&cache->cache,
+                           &cachefiles_cache_ops,
+                           "%s",
+                           fsdef->dentry->d_sb->s_id);
+
+        fscache_object_init(&fsdef->fscache, NULL, &cache->cache);
+
+        ret = fscache_add_cache(&cache->cache, &fsdef->fscache, cache->tag);
+        if (ret < 0)
+                goto error_add_cache;
+
+        /* done */
+        set_bit(CACHEFILES_READY, &cache->flags);
+        dput(root);
+
+        printk(KERN_INFO "CacheFiles:"
+               " File cache on %s registered\n",
+               cache->cache.identifier);
+
+        /* check how much space the cache has */
+        cachefiles_has_space(cache, 0, 0);
+        cachefiles_end_secure(cache, saved_cred);
+        return 0;
+
+error_add_cache:
+        dput(cache->graveyard);
+        cache->graveyard = NULL;
+error_unsupported:
+        mntput(cache->mnt);
+        cache->mnt = NULL;
+        dput(fsdef->dentry);
+        fsdef->dentry = NULL;
+        dput(root);
+error_open_root:
+        kmem_cache_free(cachefiles_object_jar, fsdef);
+error_root_object:
+        cachefiles_end_secure(cache, saved_cred);
+        kerror("Failed to register: %d", ret);
+        return ret;
+}
+
+/*
+ * unbind a cache on fd release
+ */
+void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
+{
+        _enter("");
+
+        if (test_bit(CACHEFILES_READY, &cache->flags)) {
+                printk(KERN_INFO "CacheFiles:"
+                       " File cache on %s unregistering\n",
+                       cache->cache.identifier);
+
+                fscache_withdraw_cache(&cache->cache);
+        }
+
+        dput(cache->graveyard);
+        mntput(cache->mnt);
+
+        kfree(cache->rootdirname);
+        kfree(cache->secctx);
+        kfree(cache->tag);
+
+        _leave("");
+}