3 files changed, 524 insertions, 0 deletions

diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
new file mode 100644
index 000000000000..9c3e4cc7b1a6
--- /dev/null
+++ b/fs/fuse/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for the FUSE filesystem.
+#
+
+obj-$(CONFIG_FUSE_FS) += fuse.o
+
+fuse-objs := inode.o
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
new file mode 100644
index 000000000000..eed6e89ce01f
--- /dev/null
+++ b/fs/fuse/fuse_i.h
@@ -0,0 +1,89 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2001-2005  Miklos Szeredi <miklos@szeredi.hu>
+
+  This program can be distributed under the terms of the GNU GPL.
+  See the file COPYING.
+*/
+
+#include <linux/fuse.h>
+#include <linux/fs.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/backing-dev.h>
+#include <asm/semaphore.h>
+
+/** FUSE inode */
+struct fuse_inode {
+        /** Inode data */
+        struct inode inode;
+
+        /** Unique ID, which identifies the inode between userspace
+         * and kernel */
+        u64 nodeid;
+
+        /** Time in jiffies until the file attributes are valid */
+        unsigned long i_time;
+};
+
+/**
+ * A Fuse connection.
+ *
+ * This structure is created, when the filesystem is mounted, and is
+ * destroyed, when the client device is closed and the filesystem is
+ * unmounted.
+ */
+struct fuse_conn {
+        /** The superblock of the mounted filesystem */
+        struct super_block *sb;
+
+        /** The user id for this mount */
+        uid_t user_id;
+
+        /** Backing dev info */
+        struct backing_dev_info bdi;
+};
+
+static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
+{
+        return (struct fuse_conn **) &sb->s_fs_info;
+}
+
+static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
+{
+        return *get_fuse_conn_super_p(sb);
+}
+
+static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
+{
+        return get_fuse_conn_super(inode->i_sb);
+}
+
+static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
+{
+        return container_of(inode, struct fuse_inode, inode);
+}
+
+static inline u64 get_node_id(struct inode *inode)
+{
+        return get_fuse_inode(inode)->nodeid;
+}
+
+/**
+ * This is the single global spinlock which protects FUSE's structures
+ *
+ * The following data is protected by this lock:
+ *
+ *  - the s_fs_info field of the super block
+ *  - the sb (super_block) field in fuse_conn
+ */
+extern spinlock_t fuse_lock;
+
+/**
+ * Check if the connection can be released, and if yes, then free the
+ * connection structure
+ */
+void fuse_release_conn(struct fuse_conn *fc);
+
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
new file mode 100644
index 000000000000..ea6339c2b6a1
--- /dev/null
+++ b/fs/fuse/inode.c
@@ -0,0 +1,428 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2001-2005  Miklos Szeredi <miklos@szeredi.hu>
+
+  This program can be distributed under the terms of the GNU GPL.
+  See the file COPYING.
+*/
+
+#include "fuse_i.h"
+
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/parser.h>
+#include <linux/statfs.h>
+
+MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
+MODULE_DESCRIPTION("Filesystem in Userspace");
+MODULE_LICENSE("GPL");
+
+spinlock_t fuse_lock;
+static kmem_cache_t *fuse_inode_cachep;
+static int mount_count;
+
+static int mount_max = 1000;
+module_param(mount_max, int, 0644);
+MODULE_PARM_DESC(mount_max, "Maximum number of FUSE mounts allowed, if -1 then unlimited (default: 1000)");
+
+#define FUSE_SUPER_MAGIC 0x65735546
+
+struct fuse_mount_data {
+        int fd;
+        unsigned rootmode;
+        unsigned user_id;
+};
+
+static struct inode *fuse_alloc_inode(struct super_block *sb)
+{
+        struct inode *inode;
+        struct fuse_inode *fi;
+
+        inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
+        if (!inode)
+                return NULL;
+
+        fi = get_fuse_inode(inode);
+        fi->i_time = jiffies - 1;
+        fi->nodeid = 0;
+
+        return inode;
+}
+
+static void fuse_destroy_inode(struct inode *inode)
+{
+        kmem_cache_free(fuse_inode_cachep, inode);
+}
+
+static void fuse_read_inode(struct inode *inode)
+{
+        /* No op */
+}
+
+static void fuse_clear_inode(struct inode *inode)
+{
+}
+
+void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
+{
+        if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
+                invalidate_inode_pages(inode->i_mapping);
+
+        inode->i_ino     = attr->ino;
+        inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
+        inode->i_nlink   = attr->nlink;
+        inode->i_uid     = attr->uid;
+        inode->i_gid     = attr->gid;
+        i_size_write(inode, attr->size);
+        inode->i_blksize = PAGE_CACHE_SIZE;
+        inode->i_blocks  = attr->blocks;
+        inode->i_atime.tv_sec   = attr->atime;
+        inode->i_atime.tv_nsec  = attr->atimensec;
+        inode->i_mtime.tv_sec   = attr->mtime;
+        inode->i_mtime.tv_nsec  = attr->mtimensec;
+        inode->i_ctime.tv_sec   = attr->ctime;
+        inode->i_ctime.tv_nsec  = attr->ctimensec;
+}
+
+static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
+{
+        inode->i_mode = attr->mode & S_IFMT;
+        i_size_write(inode, attr->size);
+}
+
+static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
+{
+        unsigned long nodeid = *(unsigned long *) _nodeidp;
+        if (get_node_id(inode) == nodeid)
+                return 1;
+        else
+                return 0;
+}
+
+static int fuse_inode_set(struct inode *inode, void *_nodeidp)
+{
+        unsigned long nodeid = *(unsigned long *) _nodeidp;
+        get_fuse_inode(inode)->nodeid = nodeid;
+        return 0;
+}
+
+struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
+                        int generation, struct fuse_attr *attr, int version)
+{
+        struct inode *inode;
+        struct fuse_conn *fc = get_fuse_conn_super(sb);
+        int retried = 0;
+
+ retry:
+        inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
+        if (!inode)
+                return NULL;
+
+        if ((inode->i_state & I_NEW)) {
+                inode->i_generation = generation;
+                inode->i_data.backing_dev_info = &fc->bdi;
+                fuse_init_inode(inode, attr);
+                unlock_new_inode(inode);
+        } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
+                BUG_ON(retried);
+                /* Inode has changed type, any I/O on the old should fail */
+                make_bad_inode(inode);
+                iput(inode);
+                retried = 1;
+                goto retry;
+        }
+
+        fuse_change_attributes(inode, attr);
+        inode->i_version = version;
+        return inode;
+}
+
+static void fuse_put_super(struct super_block *sb)
+{
+        struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+        spin_lock(&fuse_lock);
+        mount_count --;
+        fc->sb = NULL;
+        fc->user_id = 0;
+        fuse_release_conn(fc);
+        *get_fuse_conn_super_p(sb) = NULL;
+        spin_unlock(&fuse_lock);
+}
+
+enum {
+        OPT_FD,
+        OPT_ROOTMODE,
+        OPT_USER_ID,
+        OPT_DEFAULT_PERMISSIONS,
+        OPT_ALLOW_OTHER,
+        OPT_ALLOW_ROOT,
+        OPT_KERNEL_CACHE,
+        OPT_ERR
+};
+
+static match_table_t tokens = {
+        {OPT_FD,                        "fd=%u"},
+        {OPT_ROOTMODE,                  "rootmode=%o"},
+        {OPT_USER_ID,                   "user_id=%u"},
+        {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
+        {OPT_ALLOW_OTHER,               "allow_other"},
+        {OPT_ALLOW_ROOT,                "allow_root"},
+        {OPT_KERNEL_CACHE,              "kernel_cache"},
+        {OPT_ERR,                       NULL}
+};
+
+static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
+{
+        char *p;
+        memset(d, 0, sizeof(struct fuse_mount_data));
+        d->fd = -1;
+
+        while ((p = strsep(&opt, ",")) != NULL) {
+                int token;
+                int value;
+                substring_t args[MAX_OPT_ARGS];
+                if (!*p)
+                        continue;
+
+                token = match_token(p, tokens, args);
+                switch (token) {
+                case OPT_FD:
+                        if (match_int(&args[0], &value))
+                                return 0;
+                        d->fd = value;
+                        break;
+
+                case OPT_ROOTMODE:
+                        if (match_octal(&args[0], &value))
+                                return 0;
+                        d->rootmode = value;
+                        break;
+
+                case OPT_USER_ID:
+                        if (match_int(&args[0], &value))
+                                return 0;
+                        d->user_id = value;
+                        break;
+
+                default:
+                        return 0;
+                }
+        }
+        if (d->fd == -1)
+                return 0;
+
+        return 1;
+}
+
+static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+        struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
+
+        seq_printf(m, ",user_id=%u", fc->user_id);
+        return 0;
+}
+
+void fuse_release_conn(struct fuse_conn *fc)
+{
+        kfree(fc);
+}
+
+static struct fuse_conn *new_conn(void)
+{
+        struct fuse_conn *fc;
+
+        fc = kmalloc(sizeof(*fc), GFP_KERNEL);
+        if (fc != NULL) {
+                memset(fc, 0, sizeof(*fc));
+                fc->sb = NULL;
+                fc->user_id = 0;
+                fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
+                fc->bdi.unplug_io_fn = default_unplug_io_fn;
+        }
+        return fc;
+}
+
+static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
+{
+        struct fuse_conn *fc;
+
+        fc = new_conn();
+        if (fc == NULL)
+                return NULL;
+        spin_lock(&fuse_lock);
+        fc->sb = sb;
+        spin_unlock(&fuse_lock);
+        return fc;
+}
+
+static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
+{
+        struct fuse_attr attr;
+        memset(&attr, 0, sizeof(attr));
+
+        attr.mode = mode;
+        attr.ino = FUSE_ROOT_ID;
+        return fuse_iget(sb, 1, 0, &attr, 0);
+}
+
+static struct super_operations fuse_super_operations = {
+        .alloc_inode    = fuse_alloc_inode,
+        .destroy_inode  = fuse_destroy_inode,
+        .read_inode     = fuse_read_inode,
+        .clear_inode    = fuse_clear_inode,
+        .put_super      = fuse_put_super,
+        .show_options   = fuse_show_options,
+};
+
+static int inc_mount_count(void)
+{
+        int success = 0;
+        spin_lock(&fuse_lock);
+        mount_count ++;
+        if (mount_max == -1 || mount_count <= mount_max)
+                success = 1;
+        spin_unlock(&fuse_lock);
+        return success;
+}
+
+static int fuse_fill_super(struct super_block *sb, void *data, int silent)
+{
+        struct fuse_conn *fc;
+        struct inode *root;
+        struct fuse_mount_data d;
+        struct file *file;
+        int err;
+
+        if (!parse_fuse_opt((char *) data, &d))
+                return -EINVAL;
+
+        sb->s_blocksize = PAGE_CACHE_SIZE;
+        sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+        sb->s_magic = FUSE_SUPER_MAGIC;
+        sb->s_op = &fuse_super_operations;
+        sb->s_maxbytes = MAX_LFS_FILESIZE;
+
+        file = fget(d.fd);
+        if (!file)
+                return -EINVAL;
+
+        fc = get_conn(file, sb);
+        fput(file);
+        if (fc == NULL)
+                return -EINVAL;
+
+        fc->user_id = d.user_id;
+
+        *get_fuse_conn_super_p(sb) = fc;
+
+        err = -ENFILE;
+        if (!inc_mount_count() && current->uid != 0)
+                goto err;
+
+        err = -ENOMEM;
+        root = get_root_inode(sb, d.rootmode);
+        if (root == NULL)
+                goto err;
+
+        sb->s_root = d_alloc_root(root);
+        if (!sb->s_root) {
+                iput(root);
+                goto err;
+        }
+        return 0;
+
+ err:
+        spin_lock(&fuse_lock);
+        mount_count --;
+        fc->sb = NULL;
+        fuse_release_conn(fc);
+        spin_unlock(&fuse_lock);
+        *get_fuse_conn_super_p(sb) = NULL;
+        return err;
+}
+
+static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
+                                       int flags, const char *dev_name,
+                                       void *raw_data)
+{
+        return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
+}
+
+static struct file_system_type fuse_fs_type = {
+        .owner          = THIS_MODULE,
+        .name           = "fuse",
+        .get_sb         = fuse_get_sb,
+        .kill_sb        = kill_anon_super,
+};
+
+static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
+                                 unsigned long flags)
+{
+        struct inode * inode = foo;
+
+        if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+            SLAB_CTOR_CONSTRUCTOR)
+                inode_init_once(inode);
+}
+
+static int __init fuse_fs_init(void)
+{
+        int err;
+
+        err = register_filesystem(&fuse_fs_type);
+        if (err)
+                printk("fuse: failed to register filesystem\n");
+        else {
+                fuse_inode_cachep = kmem_cache_create("fuse_inode",
+                                                      sizeof(struct fuse_inode),
+                                                      0, SLAB_HWCACHE_ALIGN,
+                                                      fuse_inode_init_once, NULL);
+                if (!fuse_inode_cachep) {
+                        unregister_filesystem(&fuse_fs_type);
+                        err = -ENOMEM;
+                }
+        }
+
+        return err;
+}
+
+static void fuse_fs_cleanup(void)
+{
+        unregister_filesystem(&fuse_fs_type);
+        kmem_cache_destroy(fuse_inode_cachep);
+}
+
+static int __init fuse_init(void)
+{
+        int res;
+
+        printk("fuse init (API version %i.%i)\n",
+               FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
+
+        spin_lock_init(&fuse_lock);
+        res = fuse_fs_init();
+        if (res)
+                goto err;
+
+        return 0;
+
+ err:
+        return res;
+}
+
+static void __exit fuse_exit(void)
+{
+        printk(KERN_DEBUG "fuse exit\n");
+
+        fuse_fs_cleanup();
+}
+
+module_init(fuse_init);
+module_exit(fuse_exit);