diff options
Diffstat (limited to 'fs/fuse')
| -rw-r--r-- | fs/fuse/Makefile | 7 | ||||
| -rw-r--r-- | fs/fuse/fuse_i.h | 89 | ||||
| -rw-r--r-- | fs/fuse/inode.c | 428 |
3 files changed, 524 insertions, 0 deletions
diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile new file mode 100644 index 0000000..9c3e4cc --- /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 0000000..eed6e89 --- /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 0000000..ea6339c --- /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); |
