/*  FUSE: Filesystem in Userspace  Copyright (C) 2001-2006  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/parser.h>#include <linux/statfs.h> MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");MODULE_DESCRIPTION("Filesystem in Userspace");MODULE_LICENSE("GPL"); static kmem_cache_t *fuse_inode_cachep;static struct subsystem connections_subsys; struct fuse_conn_attr {	struct attribute attr;	ssize_t (*show)(struct fuse_conn *, char *);	ssize_t (*store)(struct fuse_conn *, const char *, size_t);}; #define FUSE_SUPER_MAGIC 0x65735546 struct fuse_mount_data {	int fd;	unsigned rootmode;	unsigned user_id;	unsigned group_id;	unsigned fd_present : 1;	unsigned rootmode_present : 1;	unsigned user_id_present : 1;	unsigned group_id_present : 1;	unsigned flags;	unsigned max_read;}; 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;	fi->nlookup = 0;	fi->forget_req = fuse_request_alloc();	if (!fi->forget_req) {		kmem_cache_free(fuse_inode_cachep, inode);		return NULL;	} 	return inode;} static void fuse_destroy_inode(struct inode *inode){	struct fuse_inode *fi = get_fuse_inode(inode);	if (fi->forget_req)		fuse_request_free(fi->forget_req);	kmem_cache_free(fuse_inode_cachep, inode);} static void fuse_read_inode(struct inode *inode){	/* No op */} void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,		      unsigned long nodeid, u64 nlookup){	struct fuse_forget_in *inarg = &req->misc.forget_in;	inarg->nlookup = nlookup;	req->in.h.opcode = FUSE_FORGET;	req->in.h.nodeid = nodeid;	req->in.numargs = 1;	req->in.args[0].size = sizeof(struct fuse_forget_in);	req->in.args[0].value = inarg;	request_send_noreply(fc, req);} static void fuse_clear_inode(struct inode *inode){	if (inode->i_sb->s_flags & MS_ACTIVE) {		struct fuse_conn *fc = get_fuse_conn(inode);		struct fuse_inode *fi = get_fuse_inode(inode);		fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);		fi->forget_req = NULL;	}} 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);	if (S_ISREG(inode->i_mode)) {		fuse_init_common(inode);		fuse_init_file_inode(inode);	} else if (S_ISDIR(inode->i_mode))		fuse_init_dir(inode);	else if (S_ISLNK(inode->i_mode))		fuse_init_symlink(inode);	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {		fuse_init_common(inode);		init_special_inode(inode, inode->i_mode,				   new_decode_dev(attr->rdev));	} else		BUG();} 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){	struct inode *inode;	struct fuse_inode *fi;	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_flags |= S_NOATIME|S_NOCMTIME;		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;	} 	fi = get_fuse_inode(inode);	fi->nlookup ++;	fuse_change_attributes(inode, attr);	return inode;} static void fuse_umount_begin(struct super_block *sb){	fuse_abort_conn(get_fuse_conn_super(sb));} static void fuse_put_super(struct super_block *sb){	struct fuse_conn *fc = get_fuse_conn_super(sb); 	down_write(&fc->sbput_sem);	while (!list_empty(&fc->background))		fuse_release_background(fc,					list_entry(fc->background.next,						   struct fuse_req, bg_entry)); 	spin_lock(&fc->lock);	fc->mounted = 0;	fc->connected = 0;	spin_unlock(&fc->lock);	up_write(&fc->sbput_sem);	/* Flush all readers on this fs */	kill_fasync(&fc->fasync, SIGIO, POLL_IN);	wake_up_all(&fc->waitq);	kobject_del(&fc->kobj);	kobject_put(&fc->kobj);} static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr){	stbuf->f_type    = FUSE_SUPER_MAGIC;	stbuf->f_bsize   = attr->bsize;	stbuf->f_frsize  = attr->frsize;	stbuf->f_blocks  = attr->blocks;	stbuf->f_bfree   = attr->bfree;	stbuf->f_bavail  = attr->bavail;	stbuf->f_files   = attr->files;	stbuf->f_ffree   = attr->ffree;	stbuf->f_namelen = attr->namelen;	/* fsid is left zero */} static int fuse_statfs(struct super_block *sb, struct kstatfs *buf){	struct fuse_conn *fc = get_fuse_conn_super(sb);	struct fuse_req *req;	struct fuse_statfs_out outarg;	int err; 	req = fuse_get_req(fc);	if (IS_ERR(req))		return PTR_ERR(req); 	memset(&outarg, 0, sizeof(outarg));	req->in.numargs = 0;	req->in.h.opcode = FUSE_STATFS;	req->out.numargs = 1;	req->out.args[0].size =		fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);	req->out.args[0].value = &outarg;	request_send(fc, req);	err = req->out.h.error;	if (!err)		convert_fuse_statfs(buf, &outarg.st);	fuse_put_request(fc, req);	return err;} enum {	OPT_FD,	OPT_ROOTMODE,	OPT_USER_ID,	OPT_GROUP_ID,	OPT_DEFAULT_PERMISSIONS,	OPT_ALLOW_OTHER,	OPT_MAX_READ,	OPT_ERR}; static match_table_t tokens = {	{OPT_FD,			"fd=%u"},	{OPT_ROOTMODE,			"rootmode=%o"},	{OPT_USER_ID,			"user_id=%u"},	{OPT_GROUP_ID,			"group_id=%u"},	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},	{OPT_ALLOW_OTHER,		"allow_other"},	{OPT_MAX_READ,			"max_read=%u"},	{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->max_read = ~0; 	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;			d->fd_present = 1;			break; 		case OPT_ROOTMODE:			if (match_octal(&args[0], &value))				return 0;			d->rootmode = value;			d->rootmode_present = 1;			break; 		case OPT_USER_ID:			if (match_int(&args[0], &value))				return 0;			d->user_id = value;			d->user_id_present = 1;			break; 		case OPT_GROUP_ID:			if (match_int(&args[0], &value))				return 0;			d->group_id = value;			d->group_id_present = 1;			break; 		case OPT_DEFAULT_PERMISSIONS:			d->flags |= FUSE_DEFAULT_PERMISSIONS;			break; 		case OPT_ALLOW_OTHER:			d->flags |= FUSE_ALLOW_OTHER;			break; 		case OPT_MAX_READ:			if (match_int(&args[0], &value))				return 0;			d->max_read = value;			break; 		default:			return 0;		}	} 	if (!d->fd_present || !d->rootmode_present ||	    !d->user_id_present || !d->group_id_present)		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);	seq_printf(m, ",group_id=%u", fc->group_id);	if (fc->flags & FUSE_DEFAULT_PERMISSIONS)		seq_puts(m, ",default_permissions");	if (fc->flags & FUSE_ALLOW_OTHER)		seq_puts(m, ",allow_other");	if (fc->max_read != ~0)		seq_printf(m, ",max_read=%u", fc->max_read);	return 0;} static void fuse_conn_release(struct kobject *kobj){	kfree(get_fuse_conn_kobj(kobj));} static struct fuse_conn *new_conn(void){	struct fuse_conn *fc; 	fc = kzalloc(sizeof(*fc), GFP_KERNEL);	if (fc) {		spin_lock_init(&fc->lock);		init_waitqueue_head(&fc->waitq);		init_waitqueue_head(&fc->blocked_waitq);		INIT_LIST_HEAD(&fc->pending);		INIT_LIST_HEAD(&fc->processing);		INIT_LIST_HEAD(&fc->io);		INIT_LIST_HEAD(&fc->background);		init_rwsem(&fc->sbput_sem);		kobj_set_kset_s(fc, connections_subsys);		kobject_init(&fc->kobj);		atomic_set(&fc->num_waiting, 0);		fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;		fc->bdi.unplug_io_fn = default_unplug_io_fn;		fc->reqctr = 0;		fc->blocked = 1;	}	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);} 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,	.umount_begin	= fuse_umount_begin,	.statfs		= fuse_statfs,	.show_options	= fuse_show_options,}; static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req){	struct fuse_init_out *arg = &req->misc.init_out; 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)		fc->conn_error = 1;	else {		unsigned long ra_pages; 		if (arg->minor >= 6) {			ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;			if (arg->flags & FUSE_ASYNC_READ)				fc->async_read = 1;		} else			ra_pages = fc->max_read / PAGE_CACHE_SIZE; 		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);		fc->minor = arg->minor;		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;	}	fuse_put_request(fc, req);	fc->blocked = 0;	wake_up_all(&fc->blocked_waitq);} static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req){	struct fuse_init_in *arg = &req->misc.init_in; 	arg->major = FUSE_KERNEL_VERSION;	arg->minor = FUSE_KERNEL_MINOR_VERSION;	arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;	arg->flags |= FUSE_ASYNC_READ;	req->in.h.opcode = FUSE_INIT;	req->in.numargs = 1;	req->in.args[0].size = sizeof(*arg);	req->in.args[0].value = arg;	req->out.numargs = 1;	/* Variable length arguement used for backward compatibility	   with interface version < 7.5.  Rest of init_out is zeroed	   by do_get_request(), so a short reply is not a problem */	req->out.argvar = 1;	req->out.args[0].size = sizeof(struct fuse_init_out);	req->out.args[0].value = &req->misc.init_out;	req->end = process_init_reply;	request_send_background(fc, req);} static unsigned long long conn_id(void){	/* BKL is held for ->get_sb() */	static unsigned long long ctr = 1;	return ctr++;} 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;	struct dentry *root_dentry;	struct fuse_req *init_req;	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; 	if (file->f_op != &fuse_dev_operations)

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