struct fuse_forget_link *fuse_alloc_forget(void)
{
	return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
}


static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
			       int error)
{
	struct fuse_conn *fc = fm->fc;
	struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
	struct fuse_init_out *arg = &ia->out;
	bool ok = true;

	if (error || arg->major != FUSE_KERNEL_VERSION)
		ok = false;
	else {
		unsigned long ra_pages;

		process_init_limits(fc, arg);

		if (arg->minor >= 6) {
			ra_pages = arg->max_readahead / PAGE_SIZE;
			if (arg->flags & FUSE_ASYNC_READ)
				fc->async_read = 1;
			if (!(arg->flags & FUSE_POSIX_LOCKS))
				fc->no_lock = 1;
			if (arg->minor >= 17) {
				if (!(arg->flags & FUSE_FLOCK_LOCKS))
					fc->no_flock = 1;
			} else {
				if (!(arg->flags & FUSE_POSIX_LOCKS))
					fc->no_flock = 1;
			}
			if (arg->flags & FUSE_ATOMIC_O_TRUNC)
				fc->atomic_o_trunc = 1;
			if (arg->minor >= 9) {
				/* LOOKUP has dependency on proto version */
				if (arg->flags & FUSE_EXPORT_SUPPORT)
					fc->export_support = 1;
			}
			if (arg->flags & FUSE_BIG_WRITES)
				fc->big_writes = 1;
			if (arg->flags & FUSE_DONT_MASK)
				fc->dont_mask = 1;
			if (arg->flags & FUSE_AUTO_INVAL_DATA)
				fc->auto_inval_data = 1;
			else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
				fc->explicit_inval_data = 1;
			if (arg->flags & FUSE_DO_READDIRPLUS) {
				fc->do_readdirplus = 1;
				if (arg->flags & FUSE_READDIRPLUS_AUTO)
					fc->readdirplus_auto = 1;
			}
			if (arg->flags & FUSE_ASYNC_DIO)
				fc->async_dio = 1;
			if (arg->flags & FUSE_WRITEBACK_CACHE)
				fc->writeback_cache = 1;
			if (arg->flags & FUSE_PARALLEL_DIROPS)
				fc->parallel_dirops = 1;
			if (arg->flags & FUSE_HANDLE_KILLPRIV)
				fc->handle_killpriv = 1;
			if (arg->time_gran && arg->time_gran <= 1000000000)
				fm->sb->s_time_gran = arg->time_gran;
			if ((arg->flags & FUSE_POSIX_ACL)) {
				fc->default_permissions = 1;
				fc->posix_acl = 1;
				fm->sb->s_xattr = fuse_acl_xattr_handlers;
			}
			if (arg->flags & FUSE_CACHE_SYMLINKS)
				fc->cache_symlinks = 1;
			if (arg->flags & FUSE_ABORT_ERROR)
				fc->abort_err = 1;
			if (arg->flags & FUSE_MAX_PAGES) {
				fc->max_pages =
					min_t(unsigned int, FUSE_MAX_MAX_PAGES,
					max_t(unsigned int, arg->max_pages, 1));
			}
			if (IS_ENABLED(CONFIG_FUSE_DAX) &&
			    arg->flags & FUSE_MAP_ALIGNMENT &&
			    !fuse_dax_check_alignment(fc, arg->map_alignment)) {
				ok = false;
			}
			if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) {
				fc->handle_killpriv_v2 = 1;
				fm->sb->s_flags |= SB_NOSEC;
			}
		} else {
			ra_pages = fc->max_read / PAGE_SIZE;
			fc->no_lock = 1;
			fc->no_flock = 1;
		}

		fm->sb->s_bdi->ra_pages =
				min(fm->sb->s_bdi->ra_pages, ra_pages);
		fc->minor = arg->minor;
		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
		fc->max_write = max_t(unsigned, 4096, fc->max_write);
		fc->conn_init = 1;
	}
	kfree(ia);

	if (!ok) {
		fc->conn_init = 0;
		fc->conn_error = 1;
	}

	fuse_set_initialized(fc);
	wake_up_all(&fc->blocked_waitq);
}

fuse: fix bad inode

Jan Kara's analysis of the syzbot report (edited):

  The reproducer opens a directory on FUSE filesystem, it then attaches
  dnotify mark to the open directory.  After that a fuse_do_getattr() call
  finds that attributes returned by the server are inconsistent, and calls
  make_bad_inode() which, among other things does:

          inode->i_mode = S_IFREG;

  This then confuses dnotify which doesn't tear down its structures
  properly and eventually crashes.

Avoid calling make_bad_inode() on a live inode: switch to a private flag on
the fuse inode.  Also add the test to ops which the bad_inode_ops would
have caught.

This bug goes back to the initial merge of fuse in 2.6.14...

Reported-by: syzbot+f427adf9324b92652ccc@syzkaller.appspotmail.com
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org>

static struct kmem_cache *fuse_inode_cachep;

struct list_head fuse_conn_list;

static int set_global_limit(const char *val, const struct kernel_param *kp);

unsigned max_user_bgreq;

unsigned max_user_congthresh;

static struct file_system_type fuseblk_fs_type;

static const struct fs_parameter_spec fuse_fs_parameters[] = {
	fsparam_string	("source",		OPT_SOURCE),
	fsparam_u32	("fd",			OPT_FD),
	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
	fsparam_u32	("user_id",		OPT_USER_ID),
	fsparam_u32	("group_id",		OPT_GROUP_ID),
	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
	fsparam_u32	("max_read",		OPT_MAX_READ),
	fsparam_u32	("blksize",		OPT_BLKSIZE),
	fsparam_string	("subtype",		OPT_SUBTYPE),
	{}
};

struct fuse_inode_handle {
	u64 nodeid;
	u32 generation;
}

static const struct export_operations fuse_export_operations = {
	.fh_to_dentry	= fuse_fh_to_dentry,
	.fh_to_parent	= fuse_fh_to_parent,
	.encode_fh	= fuse_encode_fh,
	.get_parent	= fuse_get_parent,
};

static const struct super_operations fuse_super_operations = {
	.alloc_inode    = fuse_alloc_inode,
	.free_inode     = fuse_free_inode,
	.evict_inode	= fuse_evict_inode,
	.write_inode	= fuse_write_inode,
	.drop_inode	= generic_delete_inode,
	.put_super	= fuse_put_super,
	.umount_begin	= fuse_umount_begin,
	.statfs		= fuse_statfs,
	.show_options	= fuse_show_options,
};

struct fuse_init_args {
	struct fuse_args args;
	struct fuse_init_in in;
	struct fuse_init_out out;
}

static const struct fs_context_operations fuse_context_ops = {
	.free		= fuse_free_fc,
	.parse_param	= fuse_parse_param,
	.reconfigure	= fuse_reconfigure,
	.get_tree	= fuse_get_tree,
};

static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_anon,
};

static struct file_system_type fuseblk_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuseblk",
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_blk,
	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};

static struct kobject *fuse_kobj;


static int no_xattr_set(const struct xattr_handler *handler,
			struct dentry *dentry, struct inode *nodee,
			const char *name, const void *value,
			size_t size, int flags)
{
	return -EOPNOTSUPP;
}

static const struct xattr_handler fuse_xattr_handler = {
	.prefix = "",
	.get    = fuse_xattr_get,
	.set    = fuse_xattr_set,
};

const struct xattr_handler *fuse_xattr_handlers[] = {
	&fuse_xattr_handler,
	NULL
};

const struct xattr_handler *fuse_acl_xattr_handlers[] = {
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_handler,
	&fuse_xattr_handler,
	NULL
};

static const struct xattr_handler fuse_no_acl_access_xattr_handler = {
	.name  = XATTR_NAME_POSIX_ACL_ACCESS,
	.flags = ACL_TYPE_ACCESS,
	.list  = no_xattr_list,
	.get   = no_xattr_get,
	.set   = no_xattr_set,
};

static const struct xattr_handler fuse_no_acl_default_xattr_handler = {
	.name  = XATTR_NAME_POSIX_ACL_DEFAULT,
	.flags = ACL_TYPE_ACCESS,
	.list  = no_xattr_list,
	.get   = no_xattr_get,
	.set   = no_xattr_set,
};

const struct xattr_handler *fuse_no_acl_xattr_handlers[] = {
	&fuse_no_acl_access_xattr_handler,
	&fuse_no_acl_default_xattr_handler,
	&fuse_xattr_handler,
	NULL
};


static int fuse_xattr_get(const struct xattr_handler *handler,
			 struct dentry *dentry, struct inode *inode,
			 const char *name, void *value, size_t size)
{
	if (fuse_is_bad(inode))
		return -EIO;

	return fuse_getxattr(inode, name, value, size);
}


static int fuse_create_open(struct inode *dir, struct dentry *entry,
			    struct file *file, unsigned flags,
			    umode_t mode)
{
	int err;
	struct inode *inode;
	struct fuse_mount *fm = get_fuse_mount(dir);
	FUSE_ARGS(args);
	struct fuse_forget_link *forget;
	struct fuse_create_in inarg;
	struct fuse_open_out outopen;
	struct fuse_entry_out outentry;
	struct fuse_inode *fi;
	struct fuse_file *ff;

	/* Userspace expects S_IFREG in create mode */
	BUG_ON((mode & S_IFMT) != S_IFREG);

	forget = fuse_alloc_forget();
	err = -ENOMEM;
	if (!forget)
		goto out_err;

	err = -ENOMEM;
	ff = fuse_file_alloc(fm);
	if (!ff)
		goto out_put_forget_req;

	if (!fm->fc->dont_mask)
		mode &= ~current_umask();

	flags &= ~O_NOCTTY;
	memset(&inarg, 0, sizeof(inarg));
	memset(&outentry, 0, sizeof(outentry));
	inarg.flags = flags;
	inarg.mode = mode;
	inarg.umask = current_umask();

	if (fm->fc->handle_killpriv_v2 && (flags & O_TRUNC) &&
	    !(flags & O_EXCL) && !capable(CAP_FSETID)) {
		inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
	}

	args.opcode = FUSE_CREATE;
	args.nodeid = get_node_id(dir);
	args.in_numargs = 2;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	args.in_args[1].size = entry->d_name.len + 1;
	args.in_args[1].value = entry->d_name.name;
	args.out_numargs = 2;
	args.out_args[0].size = sizeof(outentry);
	args.out_args[0].value = &outentry;
	args.out_args[1].size = sizeof(outopen);
	args.out_args[1].value = &outopen;
	err = fuse_simple_request(fm, &args);
	if (err)
		goto out_free_ff;

	err = -EIO;
	if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid) ||
	    fuse_invalid_attr(&outentry.attr))
		goto out_free_ff;

	ff->fh = outopen.fh;
	ff->nodeid = outentry.nodeid;
	ff->open_flags = outopen.open_flags;
	inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
			  &outentry.attr, entry_attr_timeout(&outentry), 0);
	if (!inode) {
		flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
		fuse_sync_release(NULL, ff, flags);
		fuse_queue_forget(fm->fc, forget, outentry.nodeid, 1);
		err = -ENOMEM;
		goto out_err;
	}
	kfree(forget);
	d_instantiate(entry, inode);
	fuse_change_entry_timeout(entry, &outentry);
	fuse_dir_changed(dir);
	err = finish_open(file, entry, generic_file_open);
	if (err) {
		fi = get_fuse_inode(inode);
		fuse_sync_release(fi, ff, flags);
	} else {
		file->private_data = ff;
		fuse_finish_open(inode, file);
	}
	return err;

out_free_ff:
	fuse_file_free(ff);
out_put_forget_req:
	kfree(forget);
out_err:
	return err;
}

union fuse_dentry {
	u64 time;
	struct rcu_head rcu;
}

const struct dentry_operations fuse_dentry_operations = {
	.d_revalidate	= fuse_dentry_revalidate,
	.d_delete	= fuse_dentry_delete,
#if BITS_PER_LONG < 64
	.d_init		= fuse_dentry_init,
	.d_release	= fuse_dentry_release,
#endif
	.d_automount	= fuse_dentry_automount,
};

const struct dentry_operations fuse_root_dentry_operations = {
#if BITS_PER_LONG < 64
	.d_init		= fuse_dentry_init,
	.d_release	= fuse_dentry_release,
#endif
};

static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t);

static const struct inode_operations fuse_dir_inode_operations = {
	.lookup		= fuse_lookup,
	.mkdir		= fuse_mkdir,
	.symlink	= fuse_symlink,
	.unlink		= fuse_unlink,
	.rmdir		= fuse_rmdir,
	.rename		= fuse_rename2,
	.link		= fuse_link,
	.setattr	= fuse_setattr,
	.create		= fuse_create,
	.atomic_open	= fuse_atomic_open,
	.mknod		= fuse_mknod,
	.permission	= fuse_permission,
	.getattr	= fuse_getattr,
	.listxattr	= fuse_listxattr,
	.get_acl	= fuse_get_acl,
	.set_acl	= fuse_set_acl,
};

static const struct file_operations fuse_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.iterate_shared	= fuse_readdir,
	.open		= fuse_dir_open,
	.release	= fuse_dir_release,
	.fsync		= fuse_dir_fsync,
	.unlocked_ioctl	= fuse_dir_ioctl,
	.compat_ioctl	= fuse_dir_compat_ioctl,
};

static const struct inode_operations fuse_common_inode_operations = {
	.setattr	= fuse_setattr,
	.permission	= fuse_permission,
	.getattr	= fuse_getattr,
	.listxattr	= fuse_listxattr,
	.get_acl	= fuse_get_acl,
	.set_acl	= fuse_set_acl,
};

static const struct inode_operations fuse_symlink_inode_operations = {
	.setattr	= fuse_setattr,
	.get_link	= fuse_get_link,
	.getattr	= fuse_getattr,
	.listxattr	= fuse_listxattr,
};

static const struct address_space_operations fuse_symlink_aops = {
	.readpage	= fuse_symlink_readpage,
};


static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
					     struct fuse_inode *fi)
{
	struct fuse_file *ff = __fuse_write_file_get(fc, fi);
	WARN_ON(!ff);
	return ff;
}


static int __init fuse_fs_init(void)
{
	int err;

	fuse_inode_cachep = kmem_cache_create("fuse_inode",
			sizeof(struct fuse_inode), 0,
			SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
			fuse_inode_init_once);
	err = -ENOMEM;
	if (!fuse_inode_cachep)
		goto out;

	err = register_fuseblk();
	if (err)
		goto out2;

	err = register_filesystem(&fuse_fs_type);
	if (err)
		goto out3;

	return 0;

 out3:
	unregister_fuseblk();
 out2:
	kmem_cache_destroy(fuse_inode_cachep);
 out:
	return err;
}

static struct kmem_cache *fuse_inode_cachep;

struct list_head fuse_conn_list;

static int set_global_limit(const char *val, const struct kernel_param *kp);

static struct file_system_type fuseblk_fs_type;

static const struct fs_parameter_spec fuse_fs_parameters[] = {
	fsparam_string	("source",		OPT_SOURCE),
	fsparam_u32	("fd",			OPT_FD),
	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
	fsparam_u32	("user_id",		OPT_USER_ID),
	fsparam_u32	("group_id",		OPT_GROUP_ID),
	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
	fsparam_u32	("max_read",		OPT_MAX_READ),
	fsparam_u32	("blksize",		OPT_BLKSIZE),
	fsparam_string	("subtype",		OPT_SUBTYPE),
	{}
};

struct fuse_inode_handle {
	u64 nodeid;
	u32 generation;
}

static const struct export_operations fuse_export_operations = {
	.fh_to_dentry	= fuse_fh_to_dentry,
	.fh_to_parent	= fuse_fh_to_parent,
	.encode_fh	= fuse_encode_fh,
	.get_parent	= fuse_get_parent,
};

static const struct super_operations fuse_super_operations = {
	.alloc_inode    = fuse_alloc_inode,
	.free_inode     = fuse_free_inode,
	.evict_inode	= fuse_evict_inode,
	.write_inode	= fuse_write_inode,
	.drop_inode	= generic_delete_inode,
	.put_super	= fuse_put_super,
	.umount_begin	= fuse_umount_begin,
	.statfs		= fuse_statfs,
	.show_options	= fuse_show_options,
};

struct fuse_init_args {
	struct fuse_args args;
	struct fuse_init_in in;
	struct fuse_init_out out;
}

static const struct fs_context_operations fuse_context_ops = {
	.free		= fuse_free_fc,
	.parse_param	= fuse_parse_param,
	.reconfigure	= fuse_reconfigure,
	.get_tree	= fuse_get_tree,
};

static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_anon,
};

static struct file_system_type fuseblk_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuseblk",
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_blk,
	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};

static struct kobject *fuse_kobj;


void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
{
	fud->fc = fuse_conn_get(fc);
	spin_lock(&fc->lock);
	list_add_tail(&fud->entry, &fc->devices);
	spin_unlock(&fc->lock);
}


static inline int invalid_nodeid(u64 nodeid)
{
	return !nodeid || nodeid == FUSE_ROOT_ID;
}

struct fuse_inode {
	/** Inode data */
	struct inode inode;

	/** Unique ID, which identifies the inode between userspace
	 * and kernel */
	u64 nodeid;

	/** Number of lookups on this inode */
	u64 nlookup;

	/** The request used for sending the FORGET message */
	struct fuse_forget_link *forget;

	/** Time in jiffies until the file attributes are valid */
	u64 i_time;

	/* Which attributes are invalid */
	u32 inval_mask;

	/** The sticky bit in inode->i_mode may have been removed, so
	    preserve the original mode */
	umode_t orig_i_mode;

	/** 64 bit inode number */
	u64 orig_ino;

	/** Version of last attribute change */
	u64 attr_version;

	union {
		/* Write related fields (regular file only) */
		struct {
			/* Files usable in writepage.  Protected by fi->lock */
			struct list_head write_files;

			/* Writepages pending on truncate or fsync */
			struct list_head queued_writes;

			/* Number of sent writes, a negative bias
			 * (FUSE_NOWRITE) means more writes are blocked */
			int writectr;

			/* Waitq for writepage completion */
			wait_queue_head_t page_waitq;

			/* List of writepage requestst (pending or sent) */
			struct rb_root writepages;
		};

		/* readdir cache (directory only) */
		struct {
			/* true if fully cached */
			bool cached;

			/* size of cache */
			loff_t size;

			/* position at end of cache (position of next entry) */
			loff_t pos;

			/* version of the cache */
			u64 version;

			/* modification time of directory when cache was
			 * started */
			struct timespec64 mtime;

			/* iversion of directory when cache was started */
			u64 iversion;

			/* protects above fields */
			spinlock_t lock;
		} rdc;
	};

	/** Miscellaneous bits describing inode state */
	unsigned long state;

	/** Lock for serializing lookup and readdir for back compatibility*/
	struct mutex mutex;

	/** Lock to protect write related fields */
	spinlock_t lock;

	/**
	 * Can't take inode lock in fault path (leads to circular dependency).
	 * Introduce another semaphore which can be taken in fault path and
	 * then other filesystem paths can take this to block faults.
	 */
	struct rw_semaphore i_mmap_sem;

#ifdef CONFIG_FUSE_DAX
	/*
	 * Dax specific inode data
	 */
	struct fuse_inode_dax *dax;
#endif
}


void fuse_update_ctime(struct inode *inode)
{
	if (!IS_NOCMTIME(inode)) {
		inode->i_ctime = current_time(inode);
		mark_inode_dirty_sync(inode);
	}
}


int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
{
	struct fuse_mount *fm = get_fuse_mount(inode);
	FUSE_ARGS(args);
	struct fuse_setattr_in inarg;
	struct fuse_attr_out outarg;

	memset(&inarg, 0, sizeof(inarg));
	memset(&outarg, 0, sizeof(outarg));

	inarg.valid = FATTR_MTIME;
	inarg.mtime = inode->i_mtime.tv_sec;
	inarg.mtimensec = inode->i_mtime.tv_nsec;
	if (fm->fc->minor >= 23) {
		inarg.valid |= FATTR_CTIME;
		inarg.ctime = inode->i_ctime.tv_sec;
		inarg.ctimensec = inode->i_ctime.tv_nsec;
	}
	if (ff) {
		inarg.valid |= FATTR_FH;
		inarg.fh = ff->fh;
	}
	fuse_setattr_fill(fm->fc, &args, inode, &inarg, &outarg);

	return fuse_simple_request(fm, &args);
}


static int fuse_getattr(const struct path *path, struct kstat *stat,
			u32 request_mask, unsigned int flags)
{
	struct inode *inode = d_inode(path->dentry);
	struct fuse_conn *fc = get_fuse_conn(inode);

	if (fuse_is_bad(inode))
		return -EIO;

	if (!fuse_allow_current_process(fc)) {
		if (!request_mask) {
			/*
			 * If user explicitly requested *nothing* then don't
			 * error out, but return st_dev only.
			 */
			stat->result_mask = 0;
			stat->dev = inode->i_sb->s_dev;
			return 0;
		}
		return -EACCES;
	}

	return fuse_update_get_attr(inode, NULL, stat, request_mask, flags);
}


static inline int register_fuseblk(void)
{
	return 0;
}

static struct kmem_cache *fuse_inode_cachep;

static int set_global_limit(const char *val, const struct kernel_param *kp);

static struct file_system_type fuseblk_fs_type;

static const struct fs_parameter_spec fuse_fs_parameters[] = {
	fsparam_string	("source",		OPT_SOURCE),
	fsparam_u32	("fd",			OPT_FD),
	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
	fsparam_u32	("user_id",		OPT_USER_ID),
	fsparam_u32	("group_id",		OPT_GROUP_ID),
	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
	fsparam_u32	("max_read",		OPT_MAX_READ),
	fsparam_u32	("blksize",		OPT_BLKSIZE),
	fsparam_string	("subtype",		OPT_SUBTYPE),
	{}
};

static const struct export_operations fuse_export_operations = {
	.fh_to_dentry	= fuse_fh_to_dentry,
	.fh_to_parent	= fuse_fh_to_parent,
	.encode_fh	= fuse_encode_fh,
	.get_parent	= fuse_get_parent,
};

static const struct super_operations fuse_super_operations = {
	.alloc_inode    = fuse_alloc_inode,
	.free_inode     = fuse_free_inode,
	.evict_inode	= fuse_evict_inode,
	.write_inode	= fuse_write_inode,
	.drop_inode	= generic_delete_inode,
	.put_super	= fuse_put_super,
	.umount_begin	= fuse_umount_begin,
	.statfs		= fuse_statfs,
	.show_options	= fuse_show_options,
};

static const struct fs_context_operations fuse_context_ops = {
	.free		= fuse_free_fc,
	.parse_param	= fuse_parse_param,
	.reconfigure	= fuse_reconfigure,
	.get_tree	= fuse_get_tree,
};

static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_anon,
};

static struct file_system_type fuseblk_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuseblk",
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_blk,
	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};

static struct kobject *fuse_kobj;


static int fuse_readdir_cached(struct file *file, struct dir_context *ctx)
{
	struct fuse_file *ff = file->private_data;
	struct inode *inode = file_inode(file);
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	enum fuse_parse_result res;
	pgoff_t index;
	unsigned int size;
	struct page *page;
	void *addr;

	/* Seeked?  If so, reset the cache stream */
	if (ff->readdir.pos != ctx->pos) {
		ff->readdir.pos = 0;
		ff->readdir.cache_off = 0;
	}

	/*
	 * We're just about to start reading into the cache or reading the
	 * cache; both cases require an up-to-date mtime value.
	 */
	if (!ctx->pos && fc->auto_inval_data) {
		int err = fuse_update_attributes(inode, file);

		if (err)
			return err;
	}

retry:
	spin_lock(&fi->rdc.lock);
retry_locked:
	if (!fi->rdc.cached) {
		/* Starting cache? Set cache mtime. */
		if (!ctx->pos && !fi->rdc.size) {
			fi->rdc.mtime = inode->i_mtime;
			fi->rdc.iversion = inode_query_iversion(inode);
		}
		spin_unlock(&fi->rdc.lock);
		return UNCACHED;
	}
	/*
	 * When at the beginning of the directory (i.e. just after opendir(3) or
	 * rewinddir(3)), then need to check whether directory contents have
	 * changed, and reset the cache if so.
	 */
	if (!ctx->pos) {
		if (inode_peek_iversion(inode) != fi->rdc.iversion ||
		    !timespec64_equal(&fi->rdc.mtime, &inode->i_mtime)) {
			fuse_rdc_reset(inode);
			goto retry_locked;
		}
	}

	/*
	 * If cache version changed since the last getdents() call, then reset
	 * the cache stream.
	 */
	if (ff->readdir.version != fi->rdc.version) {
		ff->readdir.pos = 0;
		ff->readdir.cache_off = 0;
	}
	/*
	 * If at the beginning of the cache, than reset version to
	 * current.
	 */
	if (ff->readdir.pos == 0)
		ff->readdir.version = fi->rdc.version;

	WARN_ON(fi->rdc.size < ff->readdir.cache_off);

	index = ff->readdir.cache_off >> PAGE_SHIFT;

	if (index == (fi->rdc.size >> PAGE_SHIFT))
		size = fi->rdc.size & ~PAGE_MASK;
	else
		size = PAGE_SIZE;
	spin_unlock(&fi->rdc.lock);

	/* EOF? */
	if ((ff->readdir.cache_off & ~PAGE_MASK) == size)
		return 0;

	page = find_get_page_flags(file->f_mapping, index,
				   FGP_ACCESSED | FGP_LOCK);
	spin_lock(&fi->rdc.lock);
	if (!page) {
		/*
		 * Uh-oh: page gone missing, cache is useless
		 */
		if (fi->rdc.version == ff->readdir.version)
			fuse_rdc_reset(inode);
		goto retry_locked;
	}

	/* Make sure it's still the same version after getting the page. */
	if (ff->readdir.version != fi->rdc.version) {
		spin_unlock(&fi->rdc.lock);
		unlock_page(page);
		put_page(page);
		goto retry;
	}
	spin_unlock(&fi->rdc.lock);

	/*
	 * Contents of the page are now protected against changing by holding
	 * the page lock.
	 */
	addr = kmap(page);
	res = fuse_parse_cache(ff, addr, size, ctx);
	kunmap(page);
	unlock_page(page);
	put_page(page);

	if (res == FOUND_ERR)
		return -EIO;

	if (res == FOUND_ALL)
		return 0;

	if (size == PAGE_SIZE) {
		/* We hit end of page: skip to next page. */
		ff->readdir.cache_off = ALIGN(ff->readdir.cache_off, PAGE_SIZE);
		goto retry;
	}

	/*
	 * End of cache reached.  If found position, then we are done, otherwise
	 * need to fall back to uncached, since the position we were looking for
	 * wasn't in the cache.
	 */
	return res == FOUND_SOME ? 0 : UNCACHED;
}

enum fuse_parse_result {
	FOUND_ERR = -1,
	FOUND_NONE = 0,
	FOUND_SOME,
	FOUND_ALL,
}

#define UNCACHED 1


void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o)
{
	fuse_dentry_settime(entry,
		time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
}


static void __fuse_release_nowrite(struct inode *inode)
{
	struct fuse_inode *fi = get_fuse_inode(inode);

	BUG_ON(fi->writectr != FUSE_NOWRITE);
	fi->writectr = 0;
	fuse_flush_writepages(inode);
}


static inline u64 fuse_dentry_time(const struct dentry *entry)
{
	return ((union fuse_dentry *) entry->d_fsdata)->time;
}


static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
			     struct dir_context *ctx, u64 attr_version)
{
	struct fuse_direntplus *direntplus;
	struct fuse_dirent *dirent;
	size_t reclen;
	int over = 0;
	int ret;

	while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
		direntplus = (struct fuse_direntplus *) buf;
		dirent = &direntplus->dirent;
		reclen = FUSE_DIRENTPLUS_SIZE(direntplus);

		if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
			return -EIO;
		if (reclen > nbytes)
			break;
		if (memchr(dirent->name, '/', dirent->namelen) != NULL)
			return -EIO;

		if (!over) {
			/* We fill entries into dstbuf only as much as
			   it can hold. But we still continue iterating
			   over remaining entries to link them. If not,
			   we need to send a FORGET for each of those
			   which we did not link.
			*/
			over = !fuse_emit(file, ctx, dirent);
			if (!over)
				ctx->pos = dirent->off;
		}

		buf += reclen;
		nbytes -= reclen;

		ret = fuse_direntplus_link(file, direntplus, attr_version);
		if (ret)
			fuse_force_forget(file, direntplus->entry_out.nodeid);
	}

	return 0;
}

#define UNCACHED 1

enum fuse_parse_result {
	FOUND_ERR = -1,
	FOUND_NONE = 0,
	FOUND_SOME,
	FOUND_ALL,
}


static int fuse_show_options(struct seq_file *m, struct dentry *root)
{
	struct super_block *sb = root->d_sb;
	struct fuse_conn *fc = get_fuse_conn_super(sb);

	if (fc->legacy_opts_show) {
		seq_printf(m, ",user_id=%u",
			   from_kuid_munged(fc->user_ns, fc->user_id));
		seq_printf(m, ",group_id=%u",
			   from_kgid_munged(fc->user_ns, fc->group_id));
		if (fc->default_permissions)
			seq_puts(m, ",default_permissions");
		if (fc->allow_other)
			seq_puts(m, ",allow_other");
		if (fc->max_read != ~0)
			seq_printf(m, ",max_read=%u", fc->max_read);
		if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
			seq_printf(m, ",blksize=%lu", sb->s_blocksize);
	}
#ifdef CONFIG_FUSE_DAX
	if (fc->dax)
		seq_puts(m, ",dax");
#endif

	return 0;
}

static struct kmem_cache *fuse_inode_cachep;

struct list_head fuse_conn_list;

static int set_global_limit(const char *val, const struct kernel_param *kp);

#define FUSE_DEFAULT_BLKSIZE 512

static struct file_system_type fuseblk_fs_type;

static const struct fs_parameter_spec fuse_fs_parameters[] = {
	fsparam_string	("source",		OPT_SOURCE),
	fsparam_u32	("fd",			OPT_FD),
	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
	fsparam_u32	("user_id",		OPT_USER_ID),
	fsparam_u32	("group_id",		OPT_GROUP_ID),
	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
	fsparam_u32	("max_read",		OPT_MAX_READ),
	fsparam_u32	("blksize",		OPT_BLKSIZE),
	fsparam_string	("subtype",		OPT_SUBTYPE),
	{}
};

struct fuse_inode_handle {
	u64 nodeid;
	u32 generation;
}

static const struct export_operations fuse_export_operations = {
	.fh_to_dentry	= fuse_fh_to_dentry,
	.fh_to_parent	= fuse_fh_to_parent,
	.encode_fh	= fuse_encode_fh,
	.get_parent	= fuse_get_parent,
};

static const struct super_operations fuse_super_operations = {
	.alloc_inode    = fuse_alloc_inode,
	.free_inode     = fuse_free_inode,
	.evict_inode	= fuse_evict_inode,
	.write_inode	= fuse_write_inode,
	.drop_inode	= generic_delete_inode,
	.put_super	= fuse_put_super,
	.umount_begin	= fuse_umount_begin,
	.statfs		= fuse_statfs,
	.show_options	= fuse_show_options,
};

struct fuse_init_args {
	struct fuse_args args;
	struct fuse_init_in in;
	struct fuse_init_out out;
}

static const struct fs_context_operations fuse_context_ops = {
	.free		= fuse_free_fc,
	.parse_param	= fuse_parse_param,
	.reconfigure	= fuse_reconfigure,
	.get_tree	= fuse_get_tree,
};

static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_anon,
};

static struct file_system_type fuseblk_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuseblk",
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_blk,
	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};

static struct kobject *fuse_kobj;


int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
{
	struct fuse_dev *fud = NULL;
	struct fuse_mount *fm = get_fuse_mount_super(sb);
	struct fuse_conn *fc = fm->fc;
	struct inode *root;
	struct dentry *root_dentry;
	int err;

	err = -EINVAL;
	if (sb->s_flags & SB_MANDLOCK)
		goto err;

	fuse_sb_defaults(sb);

	if (ctx->is_bdev) {
#ifdef CONFIG_BLOCK
		err = -EINVAL;
		if (!sb_set_blocksize(sb, ctx->blksize))
			goto err;
#endif
	} else {
		sb->s_blocksize = PAGE_SIZE;
		sb->s_blocksize_bits = PAGE_SHIFT;
	}

	sb->s_subtype = ctx->subtype;
	ctx->subtype = NULL;
	if (IS_ENABLED(CONFIG_FUSE_DAX)) {
		err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
		if (err)
			goto err;
	}

	if (ctx->fudptr) {
		err = -ENOMEM;
		fud = fuse_dev_alloc_install(fc);
		if (!fud)
			goto err_free_dax;
	}

	fc->dev = sb->s_dev;
	fm->sb = sb;
	err = fuse_bdi_init(fc, sb);
	if (err)
		goto err_dev_free;

	/* Handle umasking inside the fuse code */
	if (sb->s_flags & SB_POSIXACL)
		fc->dont_mask = 1;
	sb->s_flags |= SB_POSIXACL;

	fc->default_permissions = ctx->default_permissions;
	fc->allow_other = ctx->allow_other;
	fc->user_id = ctx->user_id;
	fc->group_id = ctx->group_id;
	fc->legacy_opts_show = ctx->legacy_opts_show;
	fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
	fc->destroy = ctx->destroy;
	fc->no_control = ctx->no_control;
	fc->no_force_umount = ctx->no_force_umount;

	err = -ENOMEM;
	root = fuse_get_root_inode(sb, ctx->rootmode);
	sb->s_d_op = &fuse_root_dentry_operations;
	root_dentry = d_make_root(root);
	if (!root_dentry)
		goto err_dev_free;
	/* Root dentry doesn't have .d_revalidate */
	sb->s_d_op = &fuse_dentry_operations;

	mutex_lock(&fuse_mutex);
	err = -EINVAL;
	if (ctx->fudptr && *ctx->fudptr)
		goto err_unlock;

	err = fuse_ctl_add_conn(fc);
	if (err)
		goto err_unlock;

	list_add_tail(&fc->entry, &fuse_conn_list);
	sb->s_root = root_dentry;
	if (ctx->fudptr)
		*ctx->fudptr = fud;
	mutex_unlock(&fuse_mutex);
	return 0;

 err_unlock:
	mutex_unlock(&fuse_mutex);
	dput(root_dentry);
 err_dev_free:
	if (fud)
		fuse_dev_free(fud);
 err_free_dax:
	if (IS_ENABLED(CONFIG_FUSE_DAX))
		fuse_dax_conn_free(fc);
 err:
	return err;
}


static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
{
	int cap_sys_admin = capable(CAP_SYS_ADMIN);

	if (arg->minor < 13)
		return;

	sanitize_global_limit(&max_user_bgreq);
	sanitize_global_limit(&max_user_congthresh);

	spin_lock(&fc->bg_lock);
	if (arg->max_background) {
		fc->max_background = arg->max_background;

		if (!cap_sys_admin && fc->max_background > max_user_bgreq)
			fc->max_background = max_user_bgreq;
	}
	if (arg->congestion_threshold) {
		fc->congestion_threshold = arg->congestion_threshold;

		if (!cap_sys_admin &&
		    fc->congestion_threshold > max_user_congthresh)
			fc->congestion_threshold = max_user_congthresh;
	}
	spin_unlock(&fc->bg_lock);
}


int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
		      int datasync, int opcode)
{
	struct inode *inode = file->f_mapping->host;
	struct fuse_mount *fm = get_fuse_mount(inode);
	struct fuse_file *ff = file->private_data;
	FUSE_ARGS(args);
	struct fuse_fsync_in inarg;

	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
	inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
	args.opcode = opcode;
	args.nodeid = get_node_id(inode);
	args.in_numargs = 1;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	return fuse_simple_request(fm, &args);
}

struct fuse_release_args {
	struct fuse_args args;
	struct fuse_release_in inarg;
	struct inode *inode;
}

struct fuse_writepage_args {
	struct fuse_io_args ia;
	struct rb_node writepages_entry;
	struct list_head queue_entry;
	struct fuse_writepage_args *next;
	struct inode *inode;
}

static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);

struct fuse_fill_wb_data {
	struct fuse_writepage_args *wpa;
	struct fuse_file *ff;
	struct inode *inode;
	struct page **orig_pages;
	unsigned int max_pages;
}

static const struct vm_operations_struct fuse_file_vm_ops = {
	.close		= fuse_vma_close,
	.fault		= filemap_fault,
	.map_pages	= filemap_map_pages,
	.page_mkwrite	= fuse_page_mkwrite,
};

static const struct file_operations fuse_file_operations = {
	.llseek		= fuse_file_llseek,
	.read_iter	= fuse_file_read_iter,
	.write_iter	= fuse_file_write_iter,
	.mmap		= fuse_file_mmap,
	.open		= fuse_open,
	.flush		= fuse_flush,
	.release	= fuse_release,
	.fsync		= fuse_fsync,
	.lock		= fuse_file_lock,
	.get_unmapped_area = thp_get_unmapped_area,
	.flock		= fuse_file_flock,
	.splice_read	= generic_file_splice_read,
	.splice_write	= iter_file_splice_write,
	.unlocked_ioctl	= fuse_file_ioctl,
	.compat_ioctl	= fuse_file_compat_ioctl,
	.poll		= fuse_file_poll,
	.fallocate	= fuse_file_fallocate,
	.copy_file_range = fuse_copy_file_range,
};

static const struct address_space_operations fuse_file_aops  = {
	.readpage	= fuse_readpage,
	.readahead	= fuse_readahead,
	.writepage	= fuse_writepage,
	.writepages	= fuse_writepages,
	.launder_page	= fuse_launder_page,
	.set_page_dirty	= __set_page_dirty_nobuffers,
	.bmap		= fuse_bmap,
	.direct_IO	= fuse_direct_IO,
	.write_begin	= fuse_write_begin,
	.write_end	= fuse_write_end,
};


static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
{
	return round_up(off, fc->max_pages << PAGE_SHIFT);
}


static int fuse_flush(struct file *file, fl_owner_t id)
{
	struct inode *inode = file_inode(file);
	struct fuse_mount *fm = get_fuse_mount(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_flush_in inarg;
	FUSE_ARGS(args);
	int err;

	if (fuse_is_bad(inode))
		return -EIO;

	err = write_inode_now(inode, 1);
	if (err)
		return err;

	inode_lock(inode);
	fuse_sync_writes(inode);
	inode_unlock(inode);

	err = filemap_check_errors(file->f_mapping);
	if (err)
		return err;

	err = 0;
	if (fm->fc->no_flush)
		goto inval_attr_out;

	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
	inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);
	args.opcode = FUSE_FLUSH;
	args.nodeid = get_node_id(inode);
	args.in_numargs = 1;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	args.force = true;

	err = fuse_simple_request(fm, &args);
	if (err == -ENOSYS) {
		fm->fc->no_flush = 1;
		err = 0;
	}

inval_attr_out:
	/*
	 * In memory i_blocks is not maintained by fuse, if writeback cache is
	 * enabled, i_blocks from cached attr may not be accurate.
	 */
	if (!err && fm->fc->writeback_cache)
		fuse_invalidate_attr(inode);
	return err;
}


int fuse_update_attributes(struct inode *inode, struct file *file)
{
	/* Do *not* need to get atime for internal purposes */
	return fuse_update_get_attr(inode, file, NULL,
				    STATX_BASIC_STATS & ~STATX_ATIME, 0);
}


static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
				loff_t length)
{
	struct fuse_file *ff = file->private_data;
	struct inode *inode = file_inode(file);
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct fuse_mount *fm = ff->fm;
	FUSE_ARGS(args);
	struct fuse_fallocate_in inarg = {
		.fh = ff->fh,
		.offset = offset,
		.length = length,
		.mode = mode
	};
	int err;
	bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
			   (mode & FALLOC_FL_PUNCH_HOLE);

	bool block_faults = FUSE_IS_DAX(inode) && lock_inode;

	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
		return -EOPNOTSUPP;

	if (fm->fc->no_fallocate)
		return -EOPNOTSUPP;

	if (lock_inode) {
		inode_lock(inode);
		if (block_faults) {
			down_write(&fi->i_mmap_sem);
			err = fuse_dax_break_layouts(inode, 0, 0);
			if (err)
				goto out;
		}

		if (mode & FALLOC_FL_PUNCH_HOLE) {
			loff_t endbyte = offset + length - 1;

			err = fuse_writeback_range(inode, offset, endbyte);
			if (err)
				goto out;
		}
	}

	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
	    offset + length > i_size_read(inode)) {
		err = inode_newsize_ok(inode, offset + length);
		if (err)
			goto out;
	}

	if (!(mode & FALLOC_FL_KEEP_SIZE))
		set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);

	args.opcode = FUSE_FALLOCATE;
	args.nodeid = ff->nodeid;
	args.in_numargs = 1;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	err = fuse_simple_request(fm, &args);
	if (err == -ENOSYS) {
		fm->fc->no_fallocate = 1;
		err = -EOPNOTSUPP;
	}
	if (err)
		goto out;

	/* we could have extended the file */
	if (!(mode & FALLOC_FL_KEEP_SIZE)) {
		bool changed = fuse_write_update_size(inode, offset + length);

		if (changed && fm->fc->writeback_cache)
			file_update_time(file);
	}

	if (mode & FALLOC_FL_PUNCH_HOLE)
		truncate_pagecache_range(inode, offset, offset + length - 1);

	fuse_invalidate_attr(inode);

out:
	if (!(mode & FALLOC_FL_KEEP_SIZE))
		clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);

	if (block_faults)
		up_write(&fi->i_mmap_sem);

	if (lock_inode)
		inode_unlock(inode);

	return err;
}


static void fuse_evict_inode(struct inode *inode)
{
	struct fuse_inode *fi = get_fuse_inode(inode);

	truncate_inode_pages_final(&inode->i_data);
	clear_inode(inode);
	if (inode->i_sb->s_flags & SB_ACTIVE) {
		struct fuse_conn *fc = get_fuse_conn(inode);

		if (FUSE_IS_DAX(inode))
			fuse_dax_inode_cleanup(inode);
		if (fi->nlookup) {
			fuse_queue_forget(fc, fi->forget, fi->nodeid,
					  fi->nlookup);
			fi->forget = NULL;
		}
	}
	if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
		WARN_ON(!list_empty(&fi->write_files));
		WARN_ON(!list_empty(&fi->queued_writes));
	}
}


static int fuse_writepage(struct page *page, struct writeback_control *wbc)
{
	int err;

	if (fuse_page_is_writeback(page->mapping->host, page->index)) {
		/*
		 * ->writepages() should be called for sync() and friends.  We
		 * should only get here on direct reclaim and then we are
		 * allowed to skip a page which is already in flight
		 */
		WARN_ON(wbc->sync_mode == WB_SYNC_ALL);

		redirty_page_for_writepage(wbc, page);
		unlock_page(page);
		return 0;
	}

	err = fuse_writepage_locked(page);
	unlock_page(page);

	return err;
}


int fuse_setxattr(struct inode *inode, const char *name, const void *value,
		  size_t size, int flags)
{
	struct fuse_mount *fm = get_fuse_mount(inode);
	FUSE_ARGS(args);
	struct fuse_setxattr_in inarg;
	int err;

	if (fm->fc->no_setxattr)
		return -EOPNOTSUPP;

	memset(&inarg, 0, sizeof(inarg));
	inarg.size = size;
	inarg.flags = flags;
	args.opcode = FUSE_SETXATTR;
	args.nodeid = get_node_id(inode);
	args.in_numargs = 3;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	args.in_args[1].size = strlen(name) + 1;
	args.in_args[1].value = name;
	args.in_args[2].size = size;
	args.in_args[2].value = value;
	err = fuse_simple_request(fm, &args);
	if (err == -ENOSYS) {
		fm->fc->no_setxattr = 1;
		err = -EOPNOTSUPP;
	}
	if (!err) {
		fuse_invalidate_attr(inode);
		fuse_update_ctime(inode);
	}
	return err;
}


static void fuse_kill_sb_anon(struct super_block *sb)
{
	fuse_sb_destroy(sb);
	kill_anon_super(sb);
}


static void fuse_sb_defaults(struct super_block *sb)
{
	sb->s_magic = FUSE_SUPER_MAGIC;
	sb->s_op = &fuse_super_operations;
	sb->s_xattr = fuse_xattr_handlers;
	sb->s_maxbytes = MAX_LFS_FILESIZE;
	sb->s_time_gran = 1;
	sb->s_export_op = &fuse_export_operations;
	sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
	if (sb->s_user_ns != &init_user_ns)
		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
	sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);

	/*
	 * If we are not in the initial user namespace posix
	 * acls must be translated.
	 */
	if (sb->s_user_ns != &init_user_ns)
		sb->s_xattr = fuse_no_acl_xattr_handlers;
}

static struct kmem_cache *fuse_inode_cachep;

struct list_head fuse_conn_list;

static int set_global_limit(const char *val, const struct kernel_param *kp);

#define FUSE_SUPER_MAGIC 0x65735546

static struct file_system_type fuseblk_fs_type;

static const struct fs_parameter_spec fuse_fs_parameters[] = {
	fsparam_string	("source",		OPT_SOURCE),
	fsparam_u32	("fd",			OPT_FD),
	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
	fsparam_u32	("user_id",		OPT_USER_ID),
	fsparam_u32	("group_id",		OPT_GROUP_ID),
	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
	fsparam_u32	("max_read",		OPT_MAX_READ),
	fsparam_u32	("blksize",		OPT_BLKSIZE),
	fsparam_string	("subtype",		OPT_SUBTYPE),
	{}
};

struct fuse_inode_handle {
	u64 nodeid;
	u32 generation;
}

static const struct export_operations fuse_export_operations = {
	.fh_to_dentry	= fuse_fh_to_dentry,
	.fh_to_parent	= fuse_fh_to_parent,
	.encode_fh	= fuse_encode_fh,
	.get_parent	= fuse_get_parent,
};

static const struct super_operations fuse_super_operations = {
	.alloc_inode    = fuse_alloc_inode,
	.free_inode     = fuse_free_inode,
	.evict_inode	= fuse_evict_inode,
	.write_inode	= fuse_write_inode,
	.drop_inode	= generic_delete_inode,
	.put_super	= fuse_put_super,
	.umount_begin	= fuse_umount_begin,
	.statfs		= fuse_statfs,
	.show_options	= fuse_show_options,
};

struct fuse_init_args {
	struct fuse_args args;
	struct fuse_init_in in;
	struct fuse_init_out out;
}

static const struct fs_context_operations fuse_context_ops = {
	.free		= fuse_free_fc,
	.parse_param	= fuse_parse_param,
	.reconfigure	= fuse_reconfigure,
	.get_tree	= fuse_get_tree,
};

static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_anon,
};

static struct file_system_type fuseblk_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuseblk",
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_blk,
	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};

static struct kobject *fuse_kobj;


static ssize_t fuse_perform_write(struct kiocb *iocb,
				  struct address_space *mapping,
				  struct iov_iter *ii, loff_t pos)
{
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	int err = 0;
	ssize_t res = 0;

	if (inode->i_size < pos + iov_iter_count(ii))
		set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);

	do {
		ssize_t count;
		struct fuse_io_args ia = {};
		struct fuse_args_pages *ap = &ia.ap;
		unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
						      fc->max_pages);

		ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
		if (!ap->pages) {
			err = -ENOMEM;
			break;
		}

		count = fuse_fill_write_pages(ap, mapping, ii, pos, nr_pages);
		if (count <= 0) {
			err = count;
		} else {
			err = fuse_send_write_pages(&ia, iocb, inode,
						    pos, count);
			if (!err) {
				size_t num_written = ia.write.out.size;

				res += num_written;
				pos += num_written;

				/* break out of the loop on short write */
				if (num_written != count)
					err = -EIO;
			}
		}
		kfree(ap->pages);
	} while (!err && iov_iter_count(ii));

	if (res > 0)
		fuse_write_update_size(inode, pos);

	clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
	fuse_invalidate_attr(inode);

	return res > 0 ? res : err;
}


static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
					      struct rb_node **parent_out)
{
	struct rb_node **link = &fc->polled_files.rb_node;
	struct rb_node *last = NULL;

	while (*link) {
		struct fuse_file *ff;

		last = *link;
		ff = rb_entry(last, struct fuse_file, polled_node);

		if (kh < ff->kh)
			link = &last->rb_left;
		else if (kh > ff->kh)
			link = &last->rb_right;
		else
			return link;
	}

	if (parent_out)
		*parent_out = last;
	return link;
}


static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
	ssize_t res;

	if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
		res = fuse_direct_IO(iocb, to);
	} else {
		struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);

		res = __fuse_direct_read(&io, to, &iocb->ki_pos);
	}

	return res;
}


static void fuse_dentry_settime(struct dentry *dentry, u64 time)
{
	struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
	bool delete = !time && fc->delete_stale;
	/*
	 * Mess with DCACHE_OP_DELETE because dput() will be faster without it.
	 * Don't care about races, either way it's just an optimization
	 */
	if ((!delete && (dentry->d_flags & DCACHE_OP_DELETE)) ||
	    (delete && !(dentry->d_flags & DCACHE_OP_DELETE))) {
		spin_lock(&dentry->d_lock);
		if (!delete)
			dentry->d_flags &= ~DCACHE_OP_DELETE;
		else
			dentry->d_flags |= DCACHE_OP_DELETE;
		spin_unlock(&dentry->d_lock);
	}

	__fuse_dentry_settime(dentry, time);
}


static int fuse_writepage_locked(struct page *page)
{
	struct address_space *mapping = page->mapping;
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct fuse_writepage_args *wpa;
	struct fuse_args_pages *ap;
	struct page *tmp_page;
	int error = -ENOMEM;

	set_page_writeback(page);

	wpa = fuse_writepage_args_alloc();
	if (!wpa)
		goto err;
	ap = &wpa->ia.ap;

	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (!tmp_page)
		goto err_free;

	error = -EIO;
	wpa->ia.ff = fuse_write_file_get(fc, fi);
	if (!wpa->ia.ff)
		goto err_nofile;

	fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);

	copy_highpage(tmp_page, page);
	wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
	wpa->next = NULL;
	ap->args.in_pages = true;
	ap->num_pages = 1;
	ap->pages[0] = tmp_page;
	ap->descs[0].offset = 0;
	ap->descs[0].length = PAGE_SIZE;
	ap->args.end = fuse_writepage_end;
	wpa->inode = inode;

	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
	inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);

	spin_lock(&fi->lock);
	tree_insert(&fi->writepages, wpa);
	list_add_tail(&wpa->queue_entry, &fi->queued_writes);
	fuse_flush_writepages(inode);
	spin_unlock(&fi->lock);

	end_page_writeback(page);

	return 0;

err_nofile:
	__free_page(tmp_page);
err_free:
	kfree(wpa);
err:
	mapping_set_error(page->mapping, error);
	end_page_writeback(page);
	return error;
}


static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
{
	struct inode *inode = file->f_mapping->host;
	struct fuse_mount *fm = get_fuse_mount(inode);
	struct fuse_file *ff = file->private_data;
	FUSE_ARGS(args);
	struct fuse_lseek_in inarg = {
		.fh = ff->fh,
		.offset = offset,
		.whence = whence
	};
	struct fuse_lseek_out outarg;
	int err;

	if (fm->fc->no_lseek)
		goto fallback;

	args.opcode = FUSE_LSEEK;
	args.nodeid = ff->nodeid;
	args.in_numargs = 1;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	args.out_numargs = 1;
	args.out_args[0].size = sizeof(outarg);
	args.out_args[0].value = &outarg;
	err = fuse_simple_request(fm, &args);
	if (err) {
		if (err == -ENOSYS) {
			fm->fc->no_lseek = 1;
			goto fallback;
		}
		return err;
	}

	return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);

fallback:
	err = fuse_update_attributes(inode, file);
	if (!err)
		return generic_file_llseek(file, offset, whence);
	else
		return err;
}


static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
{
	u64 nodeid = *(u64 *) _nodeidp;
	if (get_node_id(inode) == nodeid)
		return 1;
	else
		return 0;
}


static void fuse_send_destroy(struct fuse_mount *fm)
{
	if (fm->fc->conn_init) {
		FUSE_ARGS(args);

		args.opcode = FUSE_DESTROY;
		args.force = true;
		args.nocreds = true;
		fuse_simple_request(fm, &args);
	}
}


static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
{
	struct fuse_inode *fi = get_fuse_inode(inode);

	wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
}


static u64 time_to_jiffies(u64 sec, u32 nsec)
{
	if (sec || nsec) {
		struct timespec64 ts = {
			sec,
			min_t(u32, nsec, NSEC_PER_SEC - 1)
		};

		return get_jiffies_64() + timespec64_to_jiffies(&ts);
	} else
		return 0;
}


void fuse_conn_put(struct fuse_conn *fc)
{
	if (refcount_dec_and_test(&fc->count)) {
		struct fuse_iqueue *fiq = &fc->iq;

		if (IS_ENABLED(CONFIG_FUSE_DAX))
			fuse_dax_conn_free(fc);
		if (fiq->ops->release)
			fiq->ops->release(fiq);
		put_pid_ns(fc->pid_ns);
		put_user_ns(fc->user_ns);
		fc->release(fc);
	}
}


static inline u64 get_node_id(struct inode *inode)
{
	return get_fuse_inode(inode)->nodeid;
}

extern struct list_head fuse_conn_list;

extern struct mutex fuse_mutex;

struct fuse_forget_link {
	struct fuse_forget_one forget_one;
	struct fuse_forget_link *next;
}

struct fuse_inode {
	/** Inode data */
	struct inode inode;

	/** Unique ID, which identifies the inode between userspace
	 * and kernel */
	u64 nodeid;

	/** Number of lookups on this inode */
	u64 nlookup;

	/** The request used for sending the FORGET message */
	struct fuse_forget_link *forget;

	/** Time in jiffies until the file attributes are valid */
	u64 i_time;

	/* Which attributes are invalid */
	u32 inval_mask;

	/** The sticky bit in inode->i_mode may have been removed, so
	    preserve the original mode */
	umode_t orig_i_mode;

	/** 64 bit inode number */
	u64 orig_ino;

	/** Version of last attribute change */
	u64 attr_version;

	union {
		/* Write related fields (regular file only) */
		struct {
			/* Files usable in writepage.  Protected by fi->lock */
			struct list_head write_files;

			/* Writepages pending on truncate or fsync */
			struct list_head queued_writes;

			/* Number of sent writes, a negative bias
			 * (FUSE_NOWRITE) means more writes are blocked */
			int writectr;

			/* Waitq for writepage completion */
			wait_queue_head_t page_waitq;

			/* List of writepage requestst (pending or sent) */
			struct rb_root writepages;
		};

		/* readdir cache (directory only) */
		struct {
			/* true if fully cached */
			bool cached;

			/* size of cache */
			loff_t size;

			/* position at end of cache (position of next entry) */
			loff_t pos;

			/* version of the cache */
			u64 version;

			/* modification time of directory when cache was
			 * started */
			struct timespec64 mtime;

			/* iversion of directory when cache was started */
			u64 iversion;

			/* protects above fields */
			spinlock_t lock;
		} rdc;
	};

	/** Miscellaneous bits describing inode state */
	unsigned long state;

	/** Lock for serializing lookup and readdir for back compatibility*/
	struct mutex mutex;

	/** Lock to protect write related fields */
	spinlock_t lock;

	/**
	 * Can't take inode lock in fault path (leads to circular dependency).
	 * Introduce another semaphore which can be taken in fault path and
	 * then other filesystem paths can take this to block faults.
	 */
	struct rw_semaphore i_mmap_sem;

#ifdef CONFIG_FUSE_DAX
	/*
	 * Dax specific inode data
	 */
	struct fuse_inode_dax *dax;
#endif
}

enum {
	/** Advise readdirplus  */
	FUSE_I_ADVISE_RDPLUS,
	/** Initialized with readdirplus */
	FUSE_I_INIT_RDPLUS,
	/** An operation changing file size is in progress  */
	FUSE_I_SIZE_UNSTABLE,
	/* Bad inode */
	FUSE_I_BAD,
}

struct fuse_conn

struct fuse_mount

struct fuse_release_args


static int fuse_setattr(struct dentry *entry, struct iattr *attr)
{
	struct inode *inode = d_inode(entry);
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL;
	int ret;

	if (fuse_is_bad(inode))
		return -EIO;

	if (!fuse_allow_current_process(get_fuse_conn(inode)))
		return -EACCES;

	if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) {
		attr->ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID |
				    ATTR_MODE);

		/*
		 * The only sane way to reliably kill suid/sgid is to do it in
		 * the userspace filesystem
		 *
		 * This should be done on write(), truncate() and chown().
		 */
		if (!fc->handle_killpriv && !fc->handle_killpriv_v2) {
			/*
			 * ia_mode calculation may have used stale i_mode.
			 * Refresh and recalculate.
			 */
			ret = fuse_do_getattr(inode, NULL, file);
			if (ret)
				return ret;

			attr->ia_mode = inode->i_mode;
			if (inode->i_mode & S_ISUID) {
				attr->ia_valid |= ATTR_MODE;
				attr->ia_mode &= ~S_ISUID;
			}
			if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
				attr->ia_valid |= ATTR_MODE;
				attr->ia_mode &= ~S_ISGID;
			}
		}
	}
	if (!attr->ia_valid)
		return 0;

	ret = fuse_do_setattr(entry, attr, file);
	if (!ret) {
		/*
		 * If filesystem supports acls it may have updated acl xattrs in
		 * the filesystem, so forget cached acls for the inode.
		 */
		if (fc->posix_acl)
			forget_all_cached_acls(inode);

		/* Directory mode changed, may need to revalidate access */
		if (d_is_dir(entry) && (attr->ia_valid & ATTR_MODE))
			fuse_invalidate_entry_cache(entry);
	}
	return ret;
}


static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
			  struct kstat *stat)
{
	unsigned int blkbits;
	struct fuse_conn *fc = get_fuse_conn(inode);

	/* see the comment in fuse_change_attributes() */
	if (fc->writeback_cache && S_ISREG(inode->i_mode)) {
		attr->size = i_size_read(inode);
		attr->mtime = inode->i_mtime.tv_sec;
		attr->mtimensec = inode->i_mtime.tv_nsec;
		attr->ctime = inode->i_ctime.tv_sec;
		attr->ctimensec = inode->i_ctime.tv_nsec;
	}

	stat->dev = inode->i_sb->s_dev;
	stat->ino = attr->ino;
	stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
	stat->nlink = attr->nlink;
	stat->uid = make_kuid(fc->user_ns, attr->uid);
	stat->gid = make_kgid(fc->user_ns, attr->gid);
	stat->rdev = inode->i_rdev;
	stat->atime.tv_sec = attr->atime;
	stat->atime.tv_nsec = attr->atimensec;
	stat->mtime.tv_sec = attr->mtime;
	stat->mtime.tv_nsec = attr->mtimensec;
	stat->ctime.tv_sec = attr->ctime;
	stat->ctime.tv_nsec = attr->ctimensec;
	stat->size = attr->size;
	stat->blocks = attr->blocks;

	if (attr->blksize != 0)
		blkbits = ilog2(attr->blksize);
	else
		blkbits = inode->i_sb->s_blocksize_bits;

	stat->blksize = 1 << blkbits;
}


bool fuse_write_update_size(struct inode *inode, loff_t pos)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	bool ret = false;

	spin_lock(&fi->lock);
	fi->attr_version = atomic64_inc_return(&fc->attr_version);
	if (pos > inode->i_size) {
		i_size_write(inode, pos);
		ret = true;
	}
	spin_unlock(&fi->lock);

	return ret;
}


static struct inode *fuse_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;
	attr.nlink = 1;
	return fuse_iget(sb, 1, 0, &attr, 0, 0);
}


static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
{
	loff_t retval;
	struct inode *inode = file_inode(file);

	switch (whence) {
	case SEEK_SET:
	case SEEK_CUR:
		 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
		retval = generic_file_llseek(file, offset, whence);
		break;
	case SEEK_END:
		inode_lock(inode);
		retval = fuse_update_attributes(inode, file);
		if (!retval)
			retval = generic_file_llseek(file, offset, whence);
		inode_unlock(inode);
		break;
	case SEEK_HOLE:
	case SEEK_DATA:
		inode_lock(inode);
		retval = fuse_lseek(file, offset, whence);
		inode_unlock(inode);
		break;
	default:
		retval = -EINVAL;
	}

	return retval;
}


int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	const char *name;
	int ret;

	if (fuse_is_bad(inode))
		return -EIO;

	if (!fc->posix_acl || fc->no_setxattr)
		return -EOPNOTSUPP;

	if (type == ACL_TYPE_ACCESS)
		name = XATTR_NAME_POSIX_ACL_ACCESS;
	else if (type == ACL_TYPE_DEFAULT)
		name = XATTR_NAME_POSIX_ACL_DEFAULT;
	else
		return -EINVAL;

	if (acl) {
		/*
		 * Fuse userspace is responsible for updating access
		 * permissions in the inode, if needed. fuse_setxattr
		 * invalidates the inode attributes, which will force
		 * them to be refreshed the next time they are used,
		 * and it also updates i_ctime.
		 */
		size_t size = posix_acl_xattr_size(acl->a_count);
		void *value;

		if (size > PAGE_SIZE)
			return -E2BIG;

		value = kmalloc(size, GFP_KERNEL);
		if (!value)
			return -ENOMEM;

		ret = posix_acl_to_xattr(fc->user_ns, acl, value, size);
		if (ret < 0) {
			kfree(value);
			return ret;
		}

		ret = fuse_setxattr(inode, name, value, size, 0);
		kfree(value);
	} else {
		ret = fuse_removexattr(inode, name);
	}
	forget_all_cached_acls(inode);
	fuse_invalidate_attr(inode);

	return ret;
}

/* No explicit global definitions found. */


static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
	struct inode *inode = file_inode(iocb->ki_filp);
	struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
	ssize_t res;

	/* Don't allow parallel writes to the same file */
	inode_lock(inode);
	res = generic_write_checks(iocb, from);
	if (res > 0) {
		if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
			res = fuse_direct_IO(iocb, from);
		} else {
			res = fuse_direct_io(&io, from, &iocb->ki_pos,
					     FUSE_DIO_WRITE);
		}
	}
	fuse_invalidate_attr(inode);
	if (res > 0)
		fuse_write_update_size(inode, iocb->ki_pos);
	inode_unlock(inode);

	return res;
}


static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
{
	int left;

	spin_lock(&io->lock);
	if (err)
		io->err = io->err ? : err;
	else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
		io->bytes = pos;

	left = --io->reqs;
	if (!left && io->blocking)
		complete(io->done);
	spin_unlock(&io->lock);

	if (!left && !io->blocking) {
		ssize_t res = fuse_get_res_by_io(io);

		if (res >= 0) {
			struct inode *inode = file_inode(io->iocb->ki_filp);
			struct fuse_conn *fc = get_fuse_conn(inode);
			struct fuse_inode *fi = get_fuse_inode(inode);

			spin_lock(&fi->lock);
			fi->attr_version = atomic64_inc_return(&fc->attr_version);
			spin_unlock(&fi->lock);
		}

		io->iocb->ki_complete(io->iocb, res, 0);
	}

	kref_put(&io->refcnt, fuse_io_release);
}


static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov,
				 size_t count)
{
	size_t n;
	u32 max = fc->max_pages << PAGE_SHIFT;

	for (n = 0; n < count; n++, iov++) {
		if (iov->iov_len > (size_t) max)
			return -ENOMEM;
		max -= iov->iov_len;
	}
	return 0;
}


static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	struct super_block *sb = dentry->d_sb;
	struct fuse_mount *fm = get_fuse_mount_super(sb);
	FUSE_ARGS(args);
	struct fuse_statfs_out outarg;
	int err;

	if (!fuse_allow_current_process(fm->fc)) {
		buf->f_type = FUSE_SUPER_MAGIC;
		return 0;
	}

	memset(&outarg, 0, sizeof(outarg));
	args.in_numargs = 0;
	args.opcode = FUSE_STATFS;
	args.nodeid = get_node_id(d_inode(dentry));
	args.out_numargs = 1;
	args.out_args[0].size = sizeof(outarg);
	args.out_args[0].value = &outarg;
	err = fuse_simple_request(fm, &args);
	if (!err)
		convert_fuse_statfs(buf, &outarg.st);
	return err;
}


int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
		     struct fuse_entry_out *outarg, struct inode **inode)
{
	struct fuse_mount *fm = get_fuse_mount_super(sb);
	FUSE_ARGS(args);
	struct fuse_forget_link *forget;
	u64 attr_version;
	int err;

	*inode = NULL;
	err = -ENAMETOOLONG;
	if (name->len > FUSE_NAME_MAX)
		goto out;

	forget = fuse_alloc_forget();
	err = -ENOMEM;
	if (!forget)
		goto out;

	attr_version = fuse_get_attr_version(fm->fc);

	fuse_lookup_init(fm->fc, &args, nodeid, name, outarg);
	err = fuse_simple_request(fm, &args);
	/* Zero nodeid is same as -ENOENT, but with valid timeout */
	if (err || !outarg->nodeid)
		goto out_put_forget;

	err = -EIO;
	if (!outarg->nodeid)
		goto out_put_forget;
	if (fuse_invalid_attr(&outarg->attr))
		goto out_put_forget;

	*inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
			   &outarg->attr, entry_attr_timeout(outarg),
			   attr_version);
	err = -ENOMEM;
	if (!*inode) {
		fuse_queue_forget(fm->fc, forget, outarg->nodeid, 1);
		goto out;
	}
	err = 0;

 out_put_forget:
	kfree(forget);
 out:
	return err;
}


static unsigned int fuse_write_flags(struct kiocb *iocb)
{
	unsigned int flags = iocb->ki_filp->f_flags;

	if (iocb->ki_flags & IOCB_DSYNC)
		flags |= O_DSYNC;
	if (iocb->ki_flags & IOCB_SYNC)
		flags |= O_SYNC;

	return flags;
}


static void fuse_dir_changed(struct inode *dir)
{
	fuse_invalidate_attr(dir);
	inode_maybe_inc_iversion(dir, false);
}


void fuse_release_common(struct file *file, bool isdir)
{
	struct fuse_inode *fi = get_fuse_inode(file_inode(file));
	struct fuse_file *ff = file->private_data;
	struct fuse_release_args *ra = ff->release_args;
	int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;

	fuse_prepare_release(fi, ff, file->f_flags, opcode);

	if (ff->flock) {
		ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
		ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc,
							  (fl_owner_t) file);
	}
	/* Hold inode until release is finished */
	ra->inode = igrab(file_inode(file));

	/*
	 * Normally this will send the RELEASE request, however if
	 * some asynchronous READ or WRITE requests are outstanding,
	 * the sending will be delayed.
	 *
	 * Make the release synchronous if this is a fuseblk mount,
	 * synchronous RELEASE is allowed (and desirable) in this case
	 * because the server can be trusted not to screw up.
	 */
	fuse_file_put(ff, ff->fm->fc->destroy, isdir);
}


static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
{
	struct fuse_file *ff = file->private_data;
	struct fuse_mount *fm = ff->fm;
	struct fuse_args_pages *ap = &ia->ap;
	loff_t pos = page_offset(ap->pages[0]);
	size_t count = ap->num_pages << PAGE_SHIFT;
	ssize_t res;
	int err;

	ap->args.out_pages = true;
	ap->args.page_zeroing = true;
	ap->args.page_replace = true;

	/* Don't overflow end offset */
	if (pos + (count - 1) == LLONG_MAX) {
		count--;
		ap->descs[ap->num_pages - 1].length--;
	}
	WARN_ON((loff_t) (pos + count) < 0);

	fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
	ia->read.attr_ver = fuse_get_attr_version(fm->fc);
	if (fm->fc->async_read) {
		ia->ff = fuse_file_get(ff);
		ap->args.end = fuse_readpages_end;
		err = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
		if (!err)
			return;
	} else {
		res = fuse_simple_request(fm, &ap->args);
		err = res < 0 ? res : 0;
	}
	fuse_readpages_end(fm, &ap->args, err);
}


static int fuse_write_begin(struct file *file, struct address_space *mapping,
		loff_t pos, unsigned len, unsigned flags,
		struct page **pagep, void **fsdata)
{
	pgoff_t index = pos >> PAGE_SHIFT;
	struct fuse_conn *fc = get_fuse_conn(file_inode(file));
	struct page *page;
	loff_t fsize;
	int err = -ENOMEM;

	WARN_ON(!fc->writeback_cache);

	page = grab_cache_page_write_begin(mapping, index, flags);
	if (!page)
		goto error;

	fuse_wait_on_page_writeback(mapping->host, page->index);

	if (PageUptodate(page) || len == PAGE_SIZE)
		goto success;
	/*
	 * Check if the start this page comes after the end of file, in which
	 * case the readpage can be optimized away.
	 */
	fsize = i_size_read(mapping->host);
	if (fsize <= (pos & PAGE_MASK)) {
		size_t off = pos & ~PAGE_MASK;
		if (off)
			zero_user_segment(page, 0, off);
		goto success;
	}
	err = fuse_do_readpage(file, page);
	if (err)
		goto cleanup;
success:
	*pagep = page;
	return 0;

cleanup:
	unlock_page(page);
	put_page(page);
error:
	return err;
}


void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags)
{
	WARN_ON(refcount_read(&ff->count) > 1);
	fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
	/*
	 * iput(NULL) is a no-op and since the refcount is 1 and everything's
	 * synchronous, we are fine with not doing igrab() here"
	 */
	fuse_file_put(ff, true, false);
}


int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct fuse_file *ff;
	int err;

	ff = __fuse_write_file_get(fc, fi);
	err = fuse_flush_times(inode, ff);
	if (ff)
		fuse_file_put(ff, false, false);

	return err;
}


static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
{
	struct fuse_args_pages *ap = &data->wpa->ia.ap;
	struct fuse_conn *fc = get_fuse_conn(data->inode);
	struct page **pages;
	struct fuse_page_desc *descs;
	unsigned int npages = min_t(unsigned int,
				    max_t(unsigned int, data->max_pages * 2,
					  FUSE_DEFAULT_MAX_PAGES_PER_REQ),
				    fc->max_pages);
	WARN_ON(npages <= data->max_pages);

	pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
	if (!pages)
		return false;

	memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
	memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
	kfree(ap->pages);
	ap->pages = pages;
	ap->descs = descs;
	data->max_pages = npages;

	return true;
}


static void fuse_put_super(struct super_block *sb)
{
	struct fuse_mount *fm = get_fuse_mount_super(sb);

	fuse_conn_put(fm->fc);
	kfree(fm);
}


int fuse_valid_type(int m)
{
	return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
		S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
}

static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t);


void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
		    struct user_namespace *user_ns,
		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
{
	memset(fc, 0, sizeof(*fc));
	spin_lock_init(&fc->lock);
	spin_lock_init(&fc->bg_lock);
	init_rwsem(&fc->killsb);
	refcount_set(&fc->count, 1);
	atomic_set(&fc->dev_count, 1);
	init_waitqueue_head(&fc->blocked_waitq);
	fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
	INIT_LIST_HEAD(&fc->bg_queue);
	INIT_LIST_HEAD(&fc->entry);
	INIT_LIST_HEAD(&fc->devices);
	atomic_set(&fc->num_waiting, 0);
	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
	atomic64_set(&fc->khctr, 0);
	fc->polled_files = RB_ROOT;
	fc->blocked = 0;
	fc->initialized = 0;
	fc->connected = 1;
	atomic64_set(&fc->attr_version, 1);
	get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
	fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
	fc->user_ns = get_user_ns(user_ns);
	fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;

	INIT_LIST_HEAD(&fc->mounts);
	list_add(&fm->fc_entry, &fc->mounts);
	fm->fc = fc;
}

static struct kmem_cache *fuse_inode_cachep;

struct list_head fuse_conn_list;

static int set_global_limit(const char *val, const struct kernel_param *kp);

#define FUSE_DEFAULT_MAX_BACKGROUND 12

#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)

static struct file_system_type fuseblk_fs_type;

static const struct fs_parameter_spec fuse_fs_parameters[] = {
	fsparam_string	("source",		OPT_SOURCE),
	fsparam_u32	("fd",			OPT_FD),
	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
	fsparam_u32	("user_id",		OPT_USER_ID),
	fsparam_u32	("group_id",		OPT_GROUP_ID),
	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
	fsparam_u32	("max_read",		OPT_MAX_READ),
	fsparam_u32	("blksize",		OPT_BLKSIZE),
	fsparam_string	("subtype",		OPT_SUBTYPE),
	{}
};

struct fuse_inode_handle {
	u64 nodeid;
	u32 generation;
}

static const struct export_operations fuse_export_operations = {
	.fh_to_dentry	= fuse_fh_to_dentry,
	.fh_to_parent	= fuse_fh_to_parent,
	.encode_fh	= fuse_encode_fh,
	.get_parent	= fuse_get_parent,
};

static const struct super_operations fuse_super_operations = {
	.alloc_inode    = fuse_alloc_inode,
	.free_inode     = fuse_free_inode,
	.evict_inode	= fuse_evict_inode,
	.write_inode	= fuse_write_inode,
	.drop_inode	= generic_delete_inode,
	.put_super	= fuse_put_super,
	.umount_begin	= fuse_umount_begin,
	.statfs		= fuse_statfs,
	.show_options	= fuse_show_options,
};

struct fuse_init_args {
	struct fuse_args args;
	struct fuse_init_in in;
	struct fuse_init_out out;
}

static const struct fs_context_operations fuse_context_ops = {
	.free		= fuse_free_fc,
	.parse_param	= fuse_parse_param,
	.reconfigure	= fuse_reconfigure,
	.get_tree	= fuse_get_tree,
};

static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_anon,
};

static struct file_system_type fuseblk_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuseblk",
	.init_fs_context = fuse_init_fs_context,
	.parameters	= fuse_fs_parameters,
	.kill_sb	= fuse_kill_sb_blk,
	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};

static struct kobject *fuse_kobj;


static struct dentry *fuse_get_dentry(struct super_block *sb,
				      struct fuse_inode_handle *handle)
{
	struct fuse_conn *fc = get_fuse_conn_super(sb);
	struct inode *inode;
	struct dentry *entry;
	int err = -ESTALE;

	if (handle->nodeid == 0)
		goto out_err;

	inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
	if (!inode) {
		struct fuse_entry_out outarg;
		const struct qstr name = QSTR_INIT(".", 1);

		if (!fc->export_support)
			goto out_err;

		err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
				       &inode);
		if (err && err != -ENOENT)
			goto out_err;
		if (err || !inode) {
			err = -ESTALE;
			goto out_err;
		}
		err = -EIO;
		if (get_node_id(inode) != handle->nodeid)
			goto out_iput;
	}
	err = -ESTALE;
	if (inode->i_generation != handle->generation)
		goto out_iput;

	entry = d_obtain_alias(inode);
	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
		fuse_invalidate_entry_cache(entry);

	return entry;

 out_iput:
	iput(inode);
 out_err:
	return ERR_PTR(err);
}


static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
				      struct file *file_out, loff_t pos_out,
				      size_t len, unsigned int flags)
{
	struct fuse_file *ff_in = file_in->private_data;
	struct fuse_file *ff_out = file_out->private_data;
	struct inode *inode_in = file_inode(file_in);
	struct inode *inode_out = file_inode(file_out);
	struct fuse_inode *fi_out = get_fuse_inode(inode_out);
	struct fuse_mount *fm = ff_in->fm;
	struct fuse_conn *fc = fm->fc;
	FUSE_ARGS(args);
	struct fuse_copy_file_range_in inarg = {
		.fh_in = ff_in->fh,
		.off_in = pos_in,
		.nodeid_out = ff_out->nodeid,
		.fh_out = ff_out->fh,
		.off_out = pos_out,
		.len = len,
		.flags = flags
	};
	struct fuse_write_out outarg;
	ssize_t err;
	/* mark unstable when write-back is not used, and file_out gets
	 * extended */
	bool is_unstable = (!fc->writeback_cache) &&
			   ((pos_out + len) > inode_out->i_size);

	if (fc->no_copy_file_range)
		return -EOPNOTSUPP;

	if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
		return -EXDEV;

	inode_lock(inode_in);
	err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
	inode_unlock(inode_in);
	if (err)
		return err;

	inode_lock(inode_out);

	err = file_modified(file_out);
	if (err)
		goto out;

	/*
	 * Write out dirty pages in the destination file before sending the COPY
	 * request to userspace.  After the request is completed, truncate off
	 * pages (including partial ones) from the cache that have been copied,
	 * since these contain stale data at that point.
	 *
	 * This should be mostly correct, but if the COPY writes to partial
	 * pages (at the start or end) and the parts not covered by the COPY are
	 * written through a memory map after calling fuse_writeback_range(),
	 * then these partial page modifications will be lost on truncation.
	 *
	 * It is unlikely that someone would rely on such mixed style
	 * modifications.  Yet this does give less guarantees than if the
	 * copying was performed with write(2).
	 *
	 * To fix this a i_mmap_sem style lock could be used to prevent new
	 * faults while the copy is ongoing.
	 */
	err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
	if (err)
		goto out;

	if (is_unstable)
		set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);

	args.opcode = FUSE_COPY_FILE_RANGE;
	args.nodeid = ff_in->nodeid;
	args.in_numargs = 1;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	args.out_numargs = 1;
	args.out_args[0].size = sizeof(outarg);
	args.out_args[0].value = &outarg;
	err = fuse_simple_request(fm, &args);
	if (err == -ENOSYS) {
		fc->no_copy_file_range = 1;
		err = -EOPNOTSUPP;
	}
	if (err)
		goto out;

	truncate_inode_pages_range(inode_out->i_mapping,
				   ALIGN_DOWN(pos_out, PAGE_SIZE),
				   ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);

	if (fc->writeback_cache) {
		fuse_write_update_size(inode_out, pos_out + outarg.size);
		file_update_time(file_out);
	}

	fuse_invalidate_attr(inode_out);

	err = outarg.size;
out:
	if (is_unstable)
		clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);

	inode_unlock(inode_out);
	file_accessed(file_in);

	return err;
}


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_encode_fh(struct inode *inode, u32 *fh, int *max_len,
			   struct inode *parent)
{
	int len = parent ? 6 : 3;
	u64 nodeid;
	u32 generation;

	if (*max_len < len) {
		*max_len = len;
		return  FILEID_INVALID;
	}

	nodeid = get_fuse_inode(inode)->nodeid;
	generation = inode->i_generation;

	fh[0] = (u32)(nodeid >> 32);
	fh[1] = (u32)(nodeid & 0xffffffff);
	fh[2] = generation;

	if (parent) {
		nodeid = get_fuse_inode(parent)->nodeid;
		generation = parent->i_generation;

		fh[3] = (u32)(nodeid >> 32);
		fh[4] = (u32)(nodeid & 0xffffffff);
		fh[5] = generation;
	}

	*max_len = len;
	return parent ? 0x82 : 0x81;
}


static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
		struct fid *fid, int fh_len, int fh_type)
{
	struct fuse_inode_handle handle;

	if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
		return NULL;

	handle.nodeid = (u64) fid->raw[0] << 32;
	handle.nodeid |= (u64) fid->raw[1];
	handle.generation = fid->raw[2];
	return fuse_get_dentry(sb, &handle);
}


static int set_global_limit(const char *val, const struct kernel_param *kp)
{
	int rv;

	rv = param_set_uint(val, kp);
	if (rv)
		return rv;

	sanitize_global_limit((unsigned *)kp->arg);

	return 0;
}


static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
					       struct fuse_inode *fi)
{
	struct fuse_file *ff = NULL;

	spin_lock(&fi->lock);
	if (!list_empty(&fi->write_files)) {
		ff = list_entry(fi->write_files.next, struct fuse_file,
				write_entry);
		fuse_file_get(ff);
	}
	spin_unlock(&fi->lock);

	return ff;
}


static void fuse_advise_use_readdirplus(struct inode *dir)
{
	struct fuse_inode *fi = get_fuse_inode(dir);

	set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
}


int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
{
	struct fuse_mount *fm = get_fuse_mount(inode);
	struct fuse_conn *fc = fm->fc;
	int err;
	bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
			  fc->atomic_o_trunc &&
			  fc->writeback_cache;
	bool dax_truncate = (file->f_flags & O_TRUNC) &&
			  fc->atomic_o_trunc && FUSE_IS_DAX(inode);

	if (fuse_is_bad(inode))
		return -EIO;

	err = generic_file_open(inode, file);
	if (err)
		return err;

	if (is_wb_truncate || dax_truncate) {
		inode_lock(inode);
		fuse_set_nowrite(inode);
	}

	if (dax_truncate) {
		down_write(&get_fuse_inode(inode)->i_mmap_sem);
		err = fuse_dax_break_layouts(inode, 0, 0);
		if (err)
			goto out;
	}

	err = fuse_do_open(fm, get_node_id(inode), file, isdir);
	if (!err)
		fuse_finish_open(inode, file);

out:
	if (dax_truncate)
		up_write(&get_fuse_inode(inode)->i_mmap_sem);

	if (is_wb_truncate | dax_truncate) {
		fuse_release_nowrite(inode);
		inode_unlock(inode);
	}

	return err;
}


int fuse_allow_current_process(struct fuse_conn *fc)
{
	const struct cred *cred;

	if (fc->allow_other)
		return current_in_userns(fc->user_ns);

	cred = current_cred();
	if (uid_eq(cred->euid, fc->user_id) &&
	    uid_eq(cred->suid, fc->user_id) &&
	    uid_eq(cred->uid,  fc->user_id) &&
	    gid_eq(cred->egid, fc->group_id) &&
	    gid_eq(cred->sgid, fc->group_id) &&
	    gid_eq(cred->gid,  fc->group_id))
		return 1;

	return 0;
}


void fuse_dev_free(struct fuse_dev *fud)
{
	struct fuse_conn *fc = fud->fc;

	if (fc) {
		spin_lock(&fc->lock);
		list_del(&fud->entry);
		spin_unlock(&fc->lock);

		fuse_conn_put(fc);
	}
	kfree(fud->pq.processing);
	kfree(fud);
}


static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
{
	return (unsigned long)ii->iov->iov_base + ii->iov_offset;
}


static int fuse_verify_xattr_list(char *list, size_t size)
{
	size_t origsize = size;

	while (size) {
		size_t thislen = strnlen(list, size);

		if (!thislen || thislen == size)
			return -EIO;

		size -= thislen + 1;
		list += thislen + 1;
	}

	return origsize;
}

static const struct xattr_handler fuse_xattr_handler = {
	.prefix = "",
	.get    = fuse_xattr_get,
	.set    = fuse_xattr_set,
};

static const struct xattr_handler fuse_no_acl_access_xattr_handler = {
	.name  = XATTR_NAME_POSIX_ACL_ACCESS,
	.flags = ACL_TYPE_ACCESS,
	.list  = no_xattr_list,
	.get   = no_xattr_get,
	.set   = no_xattr_set,
};

static const struct xattr_handler fuse_no_acl_default_xattr_handler = {
	.name  = XATTR_NAME_POSIX_ACL_DEFAULT,
	.flags = ACL_TYPE_ACCESS,
	.list  = no_xattr_list,
	.get   = no_xattr_get,
	.set   = no_xattr_set,
};


static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
{
	return get_fuse_mount_super(sb)->fc;
}

extern struct list_head fuse_conn_list;

extern struct mutex fuse_mutex;

struct fuse_forget_link {
	struct fuse_forget_one forget_one;
	struct fuse_forget_link *next;
}

struct fuse_inode {
	/** Inode data */
	struct inode inode;

	/** Unique ID, which identifies the inode between userspace
	 * and kernel */
	u64 nodeid;

	/** Number of lookups on this inode */
	u64 nlookup;

	/** The request used for sending the FORGET message */
	struct fuse_forget_link *forget;

	/** Time in jiffies until the file attributes are valid */
	u64 i_time;

	/* Which attributes are invalid */
	u32 inval_mask;

	/** The sticky bit in inode->i_mode may have been removed, so
	    preserve the original mode */
	umode_t orig_i_mode;

	/** 64 bit inode number */
	u64 orig_ino;

	/** Version of last attribute change */
	u64 attr_version;

	union {
		/* Write related fields (regular file only) */
		struct {
			/* Files usable in writepage.  Protected by fi->lock */
			struct list_head write_files;

			/* Writepages pending on truncate or fsync */
			struct list_head queued_writes;

			/* Number of sent writes, a negative bias
			 * (FUSE_NOWRITE) means more writes are blocked */
			int writectr;

			/* Waitq for writepage completion */
			wait_queue_head_t page_waitq;

			/* List of writepage requestst (pending or sent) */
			struct rb_root writepages;
		};

		/* readdir cache (directory only) */
		struct {
			/* true if fully cached */
			bool cached;

			/* size of cache */
			loff_t size;

			/* position at end of cache (position of next entry) */
			loff_t pos;

			/* version of the cache */
			u64 version;

			/* modification time of directory when cache was
			 * started */
			struct timespec64 mtime;

			/* iversion of directory when cache was started */
			u64 iversion;

			/* protects above fields */
			spinlock_t lock;
		} rdc;
	};

	/** Miscellaneous bits describing inode state */
	unsigned long state;

	/** Lock for serializing lookup and readdir for back compatibility*/
	struct mutex mutex;

	/** Lock to protect write related fields */
	spinlock_t lock;

	/**
	 * Can't take inode lock in fault path (leads to circular dependency).
	 * Introduce another semaphore which can be taken in fault path and
	 * then other filesystem paths can take this to block faults.
	 */
	struct rw_semaphore i_mmap_sem;

#ifdef CONFIG_FUSE_DAX
	/*
	 * Dax specific inode data
	 */
	struct fuse_inode_dax *dax;
#endif
}

struct fuse_conn

struct fuse_mount

struct fuse_release_args


static void fuse_do_truncate(struct file *file)
{
	struct inode *inode = file->f_mapping->host;
	struct iattr attr;

	attr.ia_valid = ATTR_SIZE;
	attr.ia_size = i_size_read(inode);

	attr.ia_file = file;
	attr.ia_valid |= ATTR_FILE;

	fuse_do_setattr(file_dentry(file), &attr, file);
}


static struct dentry *fuse_fh_to_parent(struct super_block *sb,
		struct fid *fid, int fh_len, int fh_type)
{
	struct fuse_inode_handle parent;

	if (fh_type != 0x82 || fh_len < 6)
		return NULL;

	parent.nodeid = (u64) fid->raw[3] << 32;
	parent.nodeid |= (u64) fid->raw[4];
	parent.generation = fid->raw[5];
	return fuse_get_dentry(sb, &parent);
}


static int fuse_release(struct inode *inode, struct file *file)
{
	struct fuse_conn *fc = get_fuse_conn(inode);

	/* see fuse_vma_close() for !writeback_cache case */
	if (fc->writeback_cache)
		write_inode_now(inode, 1);

	fuse_release_common(file, false);

	/* return value is ignored by VFS */
	return 0;
}


ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
		      size_t size)
{
	struct fuse_mount *fm = get_fuse_mount(inode);
	FUSE_ARGS(args);
	struct fuse_getxattr_in inarg;
	struct fuse_getxattr_out outarg;
	ssize_t ret;

	if (fm->fc->no_getxattr)
		return -EOPNOTSUPP;

	memset(&inarg, 0, sizeof(inarg));
	inarg.size = size;
	args.opcode = FUSE_GETXATTR;
	args.nodeid = get_node_id(inode);
	args.in_numargs = 2;
	args.in_args[0].size = sizeof(inarg);
	args.in_args[0].value = &inarg;
	args.in_args[1].size = strlen(name) + 1;
	args.in_args[1].value = name;
	/* This is really two different operations rolled into one */
	args.out_numargs = 1;
	if (size) {
		args.out_argvar = true;
		args.out_args[0].size = size;
		args.out_args[0].value = value;
	} else {
		args.out_args[0].size = sizeof(outarg);
		args.out_args[0].value = &outarg;
	}
	ret = fuse_simple_request(fm, &args);
	if (!ret && !size)
		ret = min_t(ssize_t, outarg.size, XATTR_SIZE_MAX);
	if (ret == -ENOSYS) {
		fm->fc->no_getxattr = 1;
		ret = -EOPNOTSUPP;
	}
	return ret;
}


static inline struct fuse_mount *get_fuse_mount_super(struct super_block *sb)
{
	return sb->s_fs_info;
}


static struct dentry *fuse_get_parent(struct dentry *child)
{
	struct inode *child_inode = d_inode(child);
	struct fuse_conn *fc = get_fuse_conn(child_inode);
	struct inode *inode;
	struct dentry *parent;
	struct fuse_entry_out outarg;
	const struct qstr name = QSTR_INIT("..", 2);
	int err;

	if (!fc->export_support)
		return ERR_PTR(-ESTALE);

	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
			       &name, &outarg, &inode);
	if (err) {
		if (err == -ENOENT)
			return ERR_PTR(-ESTALE);
		return ERR_PTR(err);
	}

	parent = d_obtain_alias(inode);
	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
		fuse_invalidate_entry_cache(parent);

	return parent;
}


static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
				  int err)
{
	struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
	struct fuse_io_priv *io = ia->io;
	ssize_t pos = -1;

	fuse_release_user_pages(&ia->ap, io->should_dirty);

	if (err) {
		/* Nothing */
	} else if (io->write) {
		if (ia->write.out.size > ia->write.in.size) {
			err = -EIO;
		} else if (ia->write.in.size != ia->write.out.size) {
			pos = ia->write.in.offset - io->offset +
				ia->write.out.size;
		}
	} else {
		u32 outsize = args->out_args[0].size;

		if (ia->read.in.size != outsize)
			pos = ia->read.in.offset - io->offset + outsize;
	}

	fuse_aio_complete(io, err, pos);
	fuse_io_free(ia);
}


static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
	struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);

	/* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
	if (fc->minor < 18)
		return -ENOTTY;

	return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
}


static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
			       size_t count, fl_owner_t owner)
{
	struct kiocb *iocb = ia->io->iocb;
	struct file *file = iocb->ki_filp;
	struct fuse_file *ff = file->private_data;
	struct fuse_mount *fm = ff->fm;
	struct fuse_write_in *inarg = &ia->write.in;
	ssize_t err;

	fuse_write_args_fill(ia, ff, pos, count);
	inarg->flags = fuse_write_flags(iocb);
	if (owner != NULL) {
		inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
		inarg->lock_owner = fuse_lock_owner_id(fm->fc, owner);
	}

	if (ia->io->async)
		return fuse_async_req_send(fm, ia, count);

	err = fuse_simple_request(fm, &ia->ap.args);
	if (!err && ia->write.out.size > count)
		err = -EIO;

	return err ?: ia->write.out.size;
}


static struct inode *fuse_alloc_inode(struct super_block *sb)
{
	struct fuse_inode *fi;

	fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
	if (!fi)
		return NULL;

	fi->i_time = 0;
	fi->inval_mask = 0;
	fi->nodeid = 0;
	fi->nlookup = 0;
	fi->attr_version = 0;
	fi->orig_ino = 0;
	fi->state = 0;
	mutex_init(&fi->mutex);
	init_rwsem(&fi->i_mmap_sem);
	spin_lock_init(&fi->lock);
	fi->forget = fuse_alloc_forget();
	if (!fi->forget)
		goto out_free;

	if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
		goto out_free_forget;

	return &fi->inode;

out_free_forget:
	kfree(fi->forget);
out_free:
	kmem_cache_free(fuse_inode_cachep, fi);
	return NULL;
}


static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
{
	struct fuse_fs_context *ctx = fsc->fs_private;
	struct file *file;
	int err;
	struct fuse_conn *fc;
	struct fuse_mount *fm;

	err = -EINVAL;
	file = fget(ctx->fd);
	if (!file)
		goto err;

	/*
	 * Require mount to happen from the same user namespace which
	 * opened /dev/fuse to prevent potential attacks.
	 */
	if ((file->f_op != &fuse_dev_operations) ||
	    (file->f_cred->user_ns != sb->s_user_ns))
		goto err_fput;
	ctx->fudptr = &file->private_data;

	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
	err = -ENOMEM;
	if (!fc)
		goto err_fput;

	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
	if (!fm) {
		kfree(fc);
		goto err_fput;
	}

	fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
	fc->release = fuse_free_conn;

	sb->s_fs_info = fm;

	err = fuse_fill_super_common(sb, ctx);
	if (err)
		goto err_put_conn;
	/*
	 * atomic_dec_and_test() in fput() provides the necessary
	 * memory barrier for file->private_data to be visible on all
	 * CPUs after this
	 */
	fput(file);
	fuse_send_init(get_fuse_mount_super(sb));
	return 0;

 err_put_conn:
	fuse_conn_put(fc);
	kfree(fm);
	sb->s_fs_info = NULL;
 err_fput:
	fput(file);
 err:
	return err;
}


static int fuse_do_readpage(struct file *file, struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct fuse_mount *fm = get_fuse_mount(inode);
	loff_t pos = page_offset(page);
	struct fuse_page_desc desc = { .length = PAGE_SIZE };
	struct fuse_io_args ia = {
		.ap.args.page_zeroing = true,
		.ap.args.out_pages = true,
		.ap.num_pages = 1,
		.ap.pages = &page,
		.ap.descs = &desc,
	};
	ssize_t res;
	u64 attr_ver;

	/*
	 * Page writeback can extend beyond the lifetime of the
	 * page-cache page, so make sure we read a properly synced
	 * page.
	 */
	fuse_wait_on_page_writeback(inode, page->index);

	attr_ver = fuse_get_attr_version(fm->fc);

	/* Don't overflow end offset */
	if (pos + (desc.length - 1) == LLONG_MAX)
		desc.length--;

	fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
	res = fuse_simple_request(fm, &ia.ap.args);
	if (res < 0)
		return res;
	/*
	 * Short read means EOF.  If file size is larger, truncate it
	 */
	if (res < desc.length)
		fuse_short_read(inode, attr_ver, res, &ia.ap);

	SetPageUptodate(page);

	return 0;
}


struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
{
	struct fuse_dev *fud;

	fud = fuse_dev_alloc();
	if (!fud)
		return NULL;

	fuse_dev_install(fud, fc);
	return fud;
}


static void fuse_free_inode(struct inode *inode)
{
	struct fuse_inode *fi = get_fuse_inode(inode);

	mutex_destroy(&fi->mutex);
	kfree(fi->forget);
#ifdef CONFIG_FUSE_DAX
	kfree(fi->dax);
#endif
	kmem_cache_free(fuse_inode_cachep, fi);
}


static void fuse_umount_begin(struct super_block *sb)
{
	struct fuse_conn *fc = get_fuse_conn_super(sb);

	if (!fc->no_force_umount)
		fuse_abort_conn(fc);
}


static bool no_xattr_list(struct dentry *dentry)
{
	return false;
}


static int fuse_dir_open(struct inode *inode, struct file *file)
{
	return fuse_open_common(inode, file, true);
}


static void fuse_rdc_reset(struct inode *inode)
{
	struct fuse_inode *fi = get_fuse_inode(inode);

	fi->rdc.cached = false;
	fi->rdc.version++;
	fi->rdc.size = 0;
	fi->rdc.pos = 0;
}


static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
				  unsigned int flags)
{
	int err;
	struct fuse_entry_out outarg;
	struct inode *inode;
	struct dentry *newent;
	bool outarg_valid = true;
	bool locked;

	if (fuse_is_bad(dir))
		return ERR_PTR(-EIO);

	locked = fuse_lock_inode(dir);
	err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
			       &outarg, &inode);
	fuse_unlock_inode(dir, locked);
	if (err == -ENOENT) {
		outarg_valid = false;
		err = 0;
	}
	if (err)
		goto out_err;

	err = -EIO;
	if (inode && get_node_id(inode) == FUSE_ROOT_ID)
		goto out_iput;

	newent = d_splice_alias(inode, entry);
	err = PTR_ERR(newent);
	if (IS_ERR(newent))
		goto out_err;

	entry = newent ? newent : entry;
	if (outarg_valid)
		fuse_change_entry_timeout(entry, &outarg);
	else
		fuse_invalidate_entry_cache(entry);

	if (inode)
		fuse_advise_use_readdirplus(dir);
	return newent;

 out_iput:
	iput(inode);
 out_err:
	return ERR_PTR(err);
}


static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
{
	if (refcount_dec_and_test(&ff->count)) {
		struct fuse_args *args = &ff->release_args->args;

		if (isdir ? ff->fm->fc->no_opendir : ff->fm->fc->no_open) {
			/* Do nothing when client does not implement 'open' */
			fuse_release_end(ff->fm, args, 0);
		} else if (sync) {
			fuse_simple_request(ff->fm, args);
			fuse_release_end(ff->fm, args, 0);
		} else {
			args->end = fuse_release_end;
			if (fuse_simple_background(ff->fm, args,
						   GFP_KERNEL | __GFP_NOFAIL))
				fuse_release_end(ff->fm, args, -ENOTCONN);
		}
		kfree(ff);
	}
}


static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
{
	struct inode *inode;
	struct dentry *parent;
	struct fuse_mount *fm;
	struct fuse_inode *fi;
	int ret;

	inode = d_inode_rcu(entry);
	if (inode && fuse_is_bad(inode))
		goto invalid;
	else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
		 (flags & (LOOKUP_EXCL | LOOKUP_REVAL))) {
		struct fuse_entry_out outarg;
		FUSE_ARGS(args);
		struct fuse_forget_link *forget;
		u64 attr_version;

		/* For negative dentries, always do a fresh lookup */
		if (!inode)
			goto invalid;

		ret = -ECHILD;
		if (flags & LOOKUP_RCU)
			goto out;

		fm = get_fuse_mount(inode);

		forget = fuse_alloc_forget();
		ret = -ENOMEM;
		if (!forget)
			goto out;

		attr_version = fuse_get_attr_version(fm->fc);

		parent = dget_parent(entry);
		fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)),
				 &entry->d_name, &outarg);
		ret = fuse_simple_request(fm, &args);
		dput(parent);
		/* Zero nodeid is same as -ENOENT */
		if (!ret && !outarg.nodeid)
			ret = -ENOENT;
		if (!ret) {
			fi = get_fuse_inode(inode);
			if (outarg.nodeid != get_node_id(inode) ||
			    (bool) IS_AUTOMOUNT(inode) != (bool) (outarg.attr.flags & FUSE_ATTR_SUBMOUNT)) {
				fuse_queue_forget(fm->fc, forget,
						  outarg.nodeid, 1);
				goto invalid;
			}
			spin_lock(&fi->lock);
			fi->nlookup++;
			spin_unlock(&fi->lock);
		}
		kfree(forget);
		if (ret == -ENOMEM)
			goto out;
		if (ret || fuse_invalid_attr(&outarg.attr) ||
		    (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
			goto invalid;

		forget_all_cached_acls(inode);
		fuse_change_attributes(inode, &outarg.attr,
				       entry_attr_timeout(&outarg),
				       attr_version);
		fuse_change_entry_timeout(entry, &outarg);
	} else if (inode) {
		fi = get_fuse_inode(inode);
		if (flags & LOOKUP_RCU) {
			if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
				return -ECHILD;
		} else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
			parent = dget_parent(entry);
			fuse_advise_use_readdirplus(d_inode(parent));
			dput(parent);
		}
	}
	ret = 1;
out:
	return ret;

invalid:
	ret = 0;
	goto out;
}


static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
{
	int err;
	char *suffix = "";

	if (sb->s_bdev) {
		suffix = "-fuseblk";
		/*
		 * sb->s_bdi points to blkdev's bdi however we want to redirect
		 * it to our private bdi...
		 */
		bdi_put(sb->s_bdi);
		sb->s_bdi = &noop_backing_dev_info;
	}
	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
				   MINOR(fc->dev), suffix);
	if (err)
		return err;

	/* fuse does it's own writeback accounting */
	sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
	sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;

	/*
	 * For a single fuse filesystem use max 1% of dirty +
	 * writeback threshold.
	 *
	 * This gives about 1M of write buffer for memory maps on a
	 * machine with 1G and 10% dirty_ratio, which should be more
	 * than enough.
	 *
	 * Privileged users can raise it by writing to
	 *
	 *    /sys/class/bdi/<bdi>/max_ratio
	 */
	bdi_set_max_ratio(sb->s_bdi, 1);

	return 0;
}


static int fuse_readpage(struct file *file, struct page *page)
{
	struct inode *inode = page->mapping->host;
	int err;

	err = -EIO;
	if (fuse_is_bad(inode))
		goto out;

	err = fuse_do_readpage(file, page);
	fuse_invalidate_atime(inode);
 out:
	unlock_page(page);
	return err;
}


static int convert_fuse_file_lock(struct fuse_conn *fc,
				  const struct fuse_file_lock *ffl,
				  struct file_lock *fl)
{
	switch (ffl->type) {
	case F_UNLCK:
		break;

	case F_RDLCK:
	case F_WRLCK:
		if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
		    ffl->end < ffl->start)
			return -EIO;

		fl->fl_start = ffl->start;
		fl->fl_end = ffl->end;

		/*
		 * Convert pid into init's pid namespace.  The locks API will
		 * translate it into the caller's pid namespace.
		 */
		rcu_read_lock();
		fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
		rcu_read_unlock();
		break;

	default:
		return -EIO;
	}
	fl->fl_type = ffl->type;
	return 0;
}


static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
			      struct inode *newdir, struct dentry *newent,
			      unsigned int flags, int opcode, size_t argsize)
{
	int err;
	struct fuse_rename2_in inarg;
	struct fuse_mount *fm = get_fuse_mount(olddir);
	FUSE_ARGS(args);

	memset(&inarg, 0, argsize);
	inarg.newdir = get_node_id(newdir);
	inarg.flags = flags;
	args.opcode = opcode;
	args.nodeid = get_node_id(olddir);
	args.in_numargs = 3;
	args.in_args[0].size = argsize;
	args.in_args[0].value = &inarg;
	args.in_args[1].size = oldent->d_name.len + 1;
	args.in_args[1].value = oldent->d_name.name;
	args.in_args[2].size = newent->d_name.len + 1;
	args.in_args[2].value = newent->d_name.name;
	err = fuse_simple_request(fm, &args);
	if (!err) {
		/* ctime changes */
		fuse_invalidate_attr(d_inode(oldent));
		fuse_update_ctime(d_inode(oldent));

		if (flags & RENAME_EXCHANGE) {
			fuse_invalidate_attr(d_inode(newent));
			fuse_update_ctime(d_inode(newent));
		}

		fuse_dir_changed(olddir);
		if (olddir != newdir)
			fuse_dir_changed(newdir);

		/* newent will end up negative */
		if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent)) {
			fuse_invalidate_attr(d_inode(newent));
			fuse_invalidate_entry_cache(newent);
			fuse_update_ctime(d_inode(newent));
		}
	} else if (err == -EINTR) {
		/* If request was interrupted, DEITY only knows if the
		   rename actually took place.  If the invalidation
		   fails (e.g. some process has CWD under the renamed
		   directory), then there can be inconsistency between
		   the dcache and the real filesystem.  Tough luck. */
		fuse_invalidate_entry(oldent);
		if (d_really_is_positive(newent))
			fuse_invalidate_entry(newent);
	}

	return err;
}


static void fuse_invalidate_attr_mask(struct inode *inode, u32 mask)
{
	set_mask_bits(&get_fuse_inode(inode)->inval_mask, 0, mask);
}


static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
			     u64 nodeid, const struct qstr *name,
			     struct fuse_entry_out *outarg)
{
	memset(outarg, 0, sizeof(struct fuse_entry_out));
	args->opcode = FUSE_LOOKUP;
	args->nodeid = nodeid;
	args->in_numargs = 1;
	args->in_args[0].size = name->len + 1;
	args->in_args[0].value = name->name;
	args->out_numargs = 1;
	args->out_args[0].size = sizeof(struct fuse_entry_out);
	args->out_args[0].value = outarg;
}


static int fuse_dir_release(struct inode *inode, struct file *file)
{
	fuse_release_common(file, true);

	return 0;
}