inode.c 29.7 KB
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/*
  FUSE: Filesystem in Userspace
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  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
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  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include "fuse_i.h"

#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/parser.h>
#include <linux/statfs.h>
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#include <linux/random.h>
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#include <linux/sched.h>
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#include <linux/exportfs.h>
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MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Filesystem in Userspace");
MODULE_LICENSE("GPL");

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static struct kmem_cache *fuse_inode_cachep;
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struct list_head fuse_conn_list;
DEFINE_MUTEX(fuse_mutex);
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static int set_global_limit(const char *val, struct kernel_param *kp);

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unsigned max_user_bgreq;
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module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
		  &max_user_bgreq, 0644);
__MODULE_PARM_TYPE(max_user_bgreq, "uint");
MODULE_PARM_DESC(max_user_bgreq,
 "Global limit for the maximum number of backgrounded requests an "
 "unprivileged user can set");

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unsigned max_user_congthresh;
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module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
		  &max_user_congthresh, 0644);
__MODULE_PARM_TYPE(max_user_congthresh, "uint");
MODULE_PARM_DESC(max_user_congthresh,
 "Global limit for the maximum congestion threshold an "
 "unprivileged user can set");

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#define FUSE_SUPER_MAGIC 0x65735546

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#define FUSE_DEFAULT_BLKSIZE 512

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/** Maximum number of outstanding background requests */
#define FUSE_DEFAULT_MAX_BACKGROUND 12

/** Congestion starts at 75% of maximum */
#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)

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struct fuse_mount_data {
	int fd;
	unsigned rootmode;
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	kuid_t user_id;
	kgid_t group_id;
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	unsigned fd_present:1;
	unsigned rootmode_present:1;
	unsigned user_id_present:1;
	unsigned group_id_present:1;
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	unsigned flags;
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	unsigned max_read;
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	unsigned blksize;
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};

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

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

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

	fi = get_fuse_inode(inode);
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	fi->i_time = 0;
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	fi->nodeid = 0;
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	fi->nlookup = 0;
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	fi->attr_version = 0;
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	fi->writectr = 0;
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	fi->orig_ino = 0;
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	fi->state = 0;
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	INIT_LIST_HEAD(&fi->write_files);
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	INIT_LIST_HEAD(&fi->queued_writes);
	INIT_LIST_HEAD(&fi->writepages);
	init_waitqueue_head(&fi->page_waitq);
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	fi->forget = fuse_alloc_forget();
	if (!fi->forget) {
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		kmem_cache_free(fuse_inode_cachep, inode);
		return NULL;
	}
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	return inode;
}

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static void fuse_i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(fuse_inode_cachep, inode);
}

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static void fuse_destroy_inode(struct inode *inode)
{
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	struct fuse_inode *fi = get_fuse_inode(inode);
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	BUG_ON(!list_empty(&fi->write_files));
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	BUG_ON(!list_empty(&fi->queued_writes));
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	kfree(fi->forget);
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	call_rcu(&inode->i_rcu, fuse_i_callback);
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}

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static void fuse_evict_inode(struct inode *inode)
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{
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	truncate_inode_pages(&inode->i_data, 0);
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	clear_inode(inode);
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	if (inode->i_sb->s_flags & MS_ACTIVE) {
		struct fuse_conn *fc = get_fuse_conn(inode);
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		struct fuse_inode *fi = get_fuse_inode(inode);
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		fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
		fi->forget = NULL;
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	}
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}

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static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
{
	if (*flags & MS_MANDLOCK)
		return -EINVAL;

	return 0;
}

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/*
 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 * so that it will fit.
 */
static ino_t fuse_squash_ino(u64 ino64)
{
	ino_t ino = (ino_t) ino64;
	if (sizeof(ino_t) < sizeof(u64))
		ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
	return ino;
}

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void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
				   u64 attr_valid)
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{
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	struct fuse_conn *fc = get_fuse_conn(inode);
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	struct fuse_inode *fi = get_fuse_inode(inode);
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	fi->attr_version = ++fc->attr_version;
	fi->i_time = attr_valid;

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	inode->i_ino     = fuse_squash_ino(attr->ino);
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	inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
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	set_nlink(inode, attr->nlink);
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	inode->i_uid     = make_kuid(&init_user_ns, attr->uid);
	inode->i_gid     = make_kgid(&init_user_ns, attr->gid);
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	inode->i_blocks  = attr->blocks;
	inode->i_atime.tv_sec   = attr->atime;
	inode->i_atime.tv_nsec  = attr->atimensec;
	inode->i_mtime.tv_sec   = attr->mtime;
	inode->i_mtime.tv_nsec  = attr->mtimensec;
	inode->i_ctime.tv_sec   = attr->ctime;
	inode->i_ctime.tv_nsec  = attr->ctimensec;
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	if (attr->blksize != 0)
		inode->i_blkbits = ilog2(attr->blksize);
	else
		inode->i_blkbits = inode->i_sb->s_blocksize_bits;

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	/*
	 * Don't set the sticky bit in i_mode, unless we want the VFS
	 * to check permissions.  This prevents failures due to the
	 * check in may_delete().
	 */
	fi->orig_i_mode = inode->i_mode;
	if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
		inode->i_mode &= ~S_ISVTX;
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	fi->orig_ino = attr->ino;
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}

void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
			    u64 attr_valid, u64 attr_version)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	loff_t oldsize;
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	struct timespec old_mtime;
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	spin_lock(&fc->lock);
	if (attr_version != 0 && fi->attr_version > attr_version) {
		spin_unlock(&fc->lock);
		return;
	}

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	old_mtime = inode->i_mtime;
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	fuse_change_attributes_common(inode, attr, attr_valid);
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	oldsize = inode->i_size;
	i_size_write(inode, attr->size);
	spin_unlock(&fc->lock);

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	if (S_ISREG(inode->i_mode)) {
		bool inval = false;

		if (oldsize != attr->size) {
			truncate_pagecache(inode, oldsize, attr->size);
			inval = true;
		} else if (fc->auto_inval_data) {
			struct timespec new_mtime = {
				.tv_sec = attr->mtime,
				.tv_nsec = attr->mtimensec,
			};

			/*
			 * Auto inval mode also checks and invalidates if mtime
			 * has changed.
			 */
			if (!timespec_equal(&old_mtime, &new_mtime))
				inval = true;
		}

		if (inval)
			invalidate_inode_pages2(inode->i_mapping);
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	}
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}

static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
{
	inode->i_mode = attr->mode & S_IFMT;
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	inode->i_size = attr->size;
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	if (S_ISREG(inode->i_mode)) {
		fuse_init_common(inode);
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		fuse_init_file_inode(inode);
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	} else if (S_ISDIR(inode->i_mode))
		fuse_init_dir(inode);
	else if (S_ISLNK(inode->i_mode))
		fuse_init_symlink(inode);
	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
		fuse_init_common(inode);
		init_special_inode(inode, inode->i_mode,
				   new_decode_dev(attr->rdev));
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	} else
		BUG();
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}

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

static int fuse_inode_set(struct inode *inode, void *_nodeidp)
{
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	u64 nodeid = *(u64 *) _nodeidp;
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	get_fuse_inode(inode)->nodeid = nodeid;
	return 0;
}

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struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
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			int generation, struct fuse_attr *attr,
			u64 attr_valid, u64 attr_version)
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{
	struct inode *inode;
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	struct fuse_inode *fi;
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	struct fuse_conn *fc = get_fuse_conn_super(sb);

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	inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
	if (!inode)
		return NULL;

	if ((inode->i_state & I_NEW)) {
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		inode->i_flags |= S_NOATIME|S_NOCMTIME;
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		inode->i_generation = generation;
		inode->i_data.backing_dev_info = &fc->bdi;
		fuse_init_inode(inode, attr);
		unlock_new_inode(inode);
	} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
		/* Inode has changed type, any I/O on the old should fail */
		make_bad_inode(inode);
		iput(inode);
		goto retry;
	}

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	fi = get_fuse_inode(inode);
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	spin_lock(&fc->lock);
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	fi->nlookup++;
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	spin_unlock(&fc->lock);
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	fuse_change_attributes(inode, attr, attr_valid, attr_version);

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	return inode;
}

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int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
			     loff_t offset, loff_t len)
{
	struct inode *inode;
	pgoff_t pg_start;
	pgoff_t pg_end;

	inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
	if (!inode)
		return -ENOENT;

	fuse_invalidate_attr(inode);
	if (offset >= 0) {
		pg_start = offset >> PAGE_CACHE_SHIFT;
		if (len <= 0)
			pg_end = -1;
		else
			pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
		invalidate_inode_pages2_range(inode->i_mapping,
					      pg_start, pg_end);
	}
	iput(inode);
	return 0;
}

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static void fuse_umount_begin(struct super_block *sb)
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{
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	fuse_abort_conn(get_fuse_conn_super(sb));
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}

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static void fuse_send_destroy(struct fuse_conn *fc)
{
	struct fuse_req *req = fc->destroy_req;
	if (req && fc->conn_init) {
		fc->destroy_req = NULL;
		req->in.h.opcode = FUSE_DESTROY;
		req->force = 1;
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		req->background = 0;
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		fuse_request_send(fc, req);
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		fuse_put_request(fc, req);
	}
}

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static void fuse_bdi_destroy(struct fuse_conn *fc)
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{
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	if (fc->bdi_initialized)
		bdi_destroy(&fc->bdi);
}
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void fuse_conn_kill(struct fuse_conn *fc)
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{
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	spin_lock(&fc->lock);
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	fc->connected = 0;
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	fc->blocked = 0;
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	fc->initialized = 1;
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	spin_unlock(&fc->lock);
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	/* Flush all readers on this fs */
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	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
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	wake_up_all(&fc->waitq);
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	wake_up_all(&fc->blocked_waitq);
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	wake_up_all(&fc->reserved_req_waitq);
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}
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EXPORT_SYMBOL_GPL(fuse_conn_kill);
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static void fuse_put_super(struct super_block *sb)
{
	struct fuse_conn *fc = get_fuse_conn_super(sb);

	fuse_send_destroy(fc);
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	fuse_conn_kill(fc);
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	mutex_lock(&fuse_mutex);
	list_del(&fc->entry);
	fuse_ctl_remove_conn(fc);
	mutex_unlock(&fuse_mutex);
	fuse_bdi_destroy(fc);

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	fuse_conn_put(fc);
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}

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static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
{
	stbuf->f_type    = FUSE_SUPER_MAGIC;
	stbuf->f_bsize   = attr->bsize;
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	stbuf->f_frsize  = attr->frsize;
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	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 */
}

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static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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	struct super_block *sb = dentry->d_sb;
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	struct fuse_conn *fc = get_fuse_conn_super(sb);
	struct fuse_req *req;
	struct fuse_statfs_out outarg;
	int err;

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

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	req = fuse_get_req_nopages(fc);
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	if (IS_ERR(req))
		return PTR_ERR(req);
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	memset(&outarg, 0, sizeof(outarg));
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	req->in.numargs = 0;
	req->in.h.opcode = FUSE_STATFS;
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	req->in.h.nodeid = get_node_id(dentry->d_inode);
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	req->out.numargs = 1;
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	req->out.args[0].size =
		fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
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	req->out.args[0].value = &outarg;
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	fuse_request_send(fc, req);
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	err = req->out.h.error;
	if (!err)
		convert_fuse_statfs(buf, &outarg.st);
	fuse_put_request(fc, req);
	return err;
}

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enum {
	OPT_FD,
	OPT_ROOTMODE,
	OPT_USER_ID,
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	OPT_GROUP_ID,
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	OPT_DEFAULT_PERMISSIONS,
	OPT_ALLOW_OTHER,
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	OPT_MAX_READ,
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	OPT_BLKSIZE,
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	OPT_ERR
};

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static const match_table_t tokens = {
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	{OPT_FD,			"fd=%u"},
	{OPT_ROOTMODE,			"rootmode=%o"},
	{OPT_USER_ID,			"user_id=%u"},
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	{OPT_GROUP_ID,			"group_id=%u"},
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	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
	{OPT_ALLOW_OTHER,		"allow_other"},
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	{OPT_MAX_READ,			"max_read=%u"},
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	{OPT_BLKSIZE,			"blksize=%u"},
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	{OPT_ERR,			NULL}
};

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static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
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{
	char *p;
	memset(d, 0, sizeof(struct fuse_mount_data));
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	d->max_read = ~0;
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	d->blksize = FUSE_DEFAULT_BLKSIZE;
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	while ((p = strsep(&opt, ",")) != NULL) {
		int token;
		int value;
		substring_t args[MAX_OPT_ARGS];
		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case OPT_FD:
			if (match_int(&args[0], &value))
				return 0;
			d->fd = value;
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			d->fd_present = 1;
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			break;

		case OPT_ROOTMODE:
			if (match_octal(&args[0], &value))
				return 0;
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			if (!fuse_valid_type(value))
				return 0;
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			d->rootmode = value;
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			d->rootmode_present = 1;
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			break;

		case OPT_USER_ID:
			if (match_int(&args[0], &value))
				return 0;
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			d->user_id = make_kuid(current_user_ns(), value);
			if (!uid_valid(d->user_id))
				return 0;
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			d->user_id_present = 1;
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			break;

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		case OPT_GROUP_ID:
			if (match_int(&args[0], &value))
				return 0;
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			d->group_id = make_kgid(current_user_ns(), value);
			if (!gid_valid(d->group_id))
				return 0;
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			d->group_id_present = 1;
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			break;

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		case OPT_DEFAULT_PERMISSIONS:
			d->flags |= FUSE_DEFAULT_PERMISSIONS;
			break;

		case OPT_ALLOW_OTHER:
			d->flags |= FUSE_ALLOW_OTHER;
			break;

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		case OPT_MAX_READ:
			if (match_int(&args[0], &value))
				return 0;
			d->max_read = value;
			break;

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		case OPT_BLKSIZE:
			if (!is_bdev || match_int(&args[0], &value))
				return 0;
			d->blksize = value;
			break;

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		default:
			return 0;
		}
	}
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	if (!d->fd_present || !d->rootmode_present ||
	    !d->user_id_present || !d->group_id_present)
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		return 0;

	return 1;
}

545
static int fuse_show_options(struct seq_file *m, struct dentry *root)
M
Miklos Szeredi 已提交
546
{
547 548
	struct super_block *sb = root->d_sb;
	struct fuse_conn *fc = get_fuse_conn_super(sb);
M
Miklos Szeredi 已提交
549

550 551
	seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
	seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
M
Miklos Szeredi 已提交
552 553 554 555
	if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
		seq_puts(m, ",default_permissions");
	if (fc->flags & FUSE_ALLOW_OTHER)
		seq_puts(m, ",allow_other");
556 557
	if (fc->max_read != ~0)
		seq_printf(m, ",max_read=%u", fc->max_read);
558 559
	if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
		seq_printf(m, ",blksize=%lu", sb->s_blocksize);
M
Miklos Szeredi 已提交
560 561 562
	return 0;
}

563
void fuse_conn_init(struct fuse_conn *fc)
M
Miklos Szeredi 已提交
564
{
565 566 567
	memset(fc, 0, sizeof(*fc));
	spin_lock_init(&fc->lock);
	mutex_init(&fc->inst_mutex);
J
John Muir 已提交
568
	init_rwsem(&fc->killsb);
569 570 571 572 573 574 575 576 577 578
	atomic_set(&fc->count, 1);
	init_waitqueue_head(&fc->waitq);
	init_waitqueue_head(&fc->blocked_waitq);
	init_waitqueue_head(&fc->reserved_req_waitq);
	INIT_LIST_HEAD(&fc->pending);
	INIT_LIST_HEAD(&fc->processing);
	INIT_LIST_HEAD(&fc->io);
	INIT_LIST_HEAD(&fc->interrupts);
	INIT_LIST_HEAD(&fc->bg_queue);
	INIT_LIST_HEAD(&fc->entry);
579
	fc->forget_list_tail = &fc->forget_list_head;
580
	atomic_set(&fc->num_waiting, 0);
581 582
	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
583 584 585
	fc->khctr = 0;
	fc->polled_files = RB_ROOT;
	fc->reqctr = 0;
586
	fc->blocked = 0;
M
Maxim Patlasov 已提交
587
	fc->initialized = 0;
588 589
	fc->attr_version = 1;
	get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
M
Miklos Szeredi 已提交
590
}
591
EXPORT_SYMBOL_GPL(fuse_conn_init);
M
Miklos Szeredi 已提交
592

593 594
void fuse_conn_put(struct fuse_conn *fc)
{
595
	if (atomic_dec_and_test(&fc->count)) {
596 597
		if (fc->destroy_req)
			fuse_request_free(fc->destroy_req);
598
		mutex_destroy(&fc->inst_mutex);
T
Tejun Heo 已提交
599
		fc->release(fc);
600
	}
601
}
602
EXPORT_SYMBOL_GPL(fuse_conn_put);
603 604 605 606 607 608

struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
{
	atomic_inc(&fc->count);
	return fc;
}
609
EXPORT_SYMBOL_GPL(fuse_conn_get);
610

611
static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
M
Miklos Szeredi 已提交
612 613 614 615 616 617
{
	struct fuse_attr attr;
	memset(&attr, 0, sizeof(attr));

	attr.mode = mode;
	attr.ino = FUSE_ROOT_ID;
618
	attr.nlink = 1;
619
	return fuse_iget(sb, 1, 0, &attr, 0, 0);
M
Miklos Szeredi 已提交
620 621
}

M
Miklos Szeredi 已提交
622
struct fuse_inode_handle {
M
Miklos Szeredi 已提交
623 624 625 626 627 628 629
	u64 nodeid;
	u32 generation;
};

static struct dentry *fuse_get_dentry(struct super_block *sb,
				      struct fuse_inode_handle *handle)
{
630
	struct fuse_conn *fc = get_fuse_conn_super(sb);
M
Miklos Szeredi 已提交
631 632 633 634 635 636 637 638
	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);
639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659
	if (!inode) {
		struct fuse_entry_out outarg;
		struct qstr name;

		if (!fc->export_support)
			goto out_err;

		name.len = 1;
		name.name = ".";
		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;
	}
M
Miklos Szeredi 已提交
660 661 662 663
	err = -ESTALE;
	if (inode->i_generation != handle->generation)
		goto out_iput;

664
	entry = d_obtain_alias(inode);
A
Al Viro 已提交
665
	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
M
Miklos Szeredi 已提交
666 667 668 669 670 671 672 673 674 675
		fuse_invalidate_entry_cache(entry);

	return entry;

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

A
Al Viro 已提交
676 677
static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
			   struct inode *parent)
M
Miklos Szeredi 已提交
678
{
A
Al Viro 已提交
679
	int len = parent ? 6 : 3;
M
Miklos Szeredi 已提交
680 681 682
	u64 nodeid;
	u32 generation;

683 684
	if (*max_len < len) {
		*max_len = len;
685
		return  FILEID_INVALID;
686
	}
M
Miklos Szeredi 已提交
687 688 689 690 691 692 693 694

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

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

A
Al Viro 已提交
695
	if (parent) {
M
Miklos Szeredi 已提交
696 697 698 699 700 701 702 703 704
		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;
A
Al Viro 已提交
705
	return parent ? 0x82 : 0x81;
M
Miklos Szeredi 已提交
706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735
}

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 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);
}

736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752
static struct dentry *fuse_get_parent(struct dentry *child)
{
	struct inode *child_inode = child->d_inode;
	struct fuse_conn *fc = get_fuse_conn(child_inode);
	struct inode *inode;
	struct dentry *parent;
	struct fuse_entry_out outarg;
	struct qstr name;
	int err;

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

	name.len = 2;
	name.name = "..";
	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
			       &name, &outarg, &inode);
753 754 755
	if (err) {
		if (err == -ENOENT)
			return ERR_PTR(-ESTALE);
756 757
		return ERR_PTR(err);
	}
758 759

	parent = d_obtain_alias(inode);
A
Al Viro 已提交
760
	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
761 762 763 764
		fuse_invalidate_entry_cache(parent);

	return parent;
}
M
Miklos Szeredi 已提交
765 766 767 768 769

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,
770
	.get_parent	= fuse_get_parent,
M
Miklos Szeredi 已提交
771 772
};

773
static const struct super_operations fuse_super_operations = {
M
Miklos Szeredi 已提交
774 775
	.alloc_inode    = fuse_alloc_inode,
	.destroy_inode  = fuse_destroy_inode,
776
	.evict_inode	= fuse_evict_inode,
M
Miklos Szeredi 已提交
777
	.drop_inode	= generic_delete_inode,
778
	.remount_fs	= fuse_remount_fs,
M
Miklos Szeredi 已提交
779
	.put_super	= fuse_put_super,
780
	.umount_begin	= fuse_umount_begin,
781
	.statfs		= fuse_statfs,
M
Miklos Szeredi 已提交
782 783 784
	.show_options	= fuse_show_options,
};

785 786 787
static void sanitize_global_limit(unsigned *limit)
{
	if (*limit == 0)
788
		*limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832
			 sizeof(struct fuse_req);

	if (*limit >= 1 << 16)
		*limit = (1 << 16) - 1;
}

static int set_global_limit(const char *val, 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 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);

	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;
	}
}

833 834 835 836 837 838 839
static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
{
	struct fuse_init_out *arg = &req->misc.init_out;

	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
		fc->conn_error = 1;
	else {
840 841
		unsigned long ra_pages;

842 843
		process_init_limits(fc, arg);

844 845 846 847
		if (arg->minor >= 6) {
			ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
			if (arg->flags & FUSE_ASYNC_READ)
				fc->async_read = 1;
848 849
			if (!(arg->flags & FUSE_POSIX_LOCKS))
				fc->no_lock = 1;
M
Miklos Szeredi 已提交
850 851 852
			if (arg->minor >= 17) {
				if (!(arg->flags & FUSE_FLOCK_LOCKS))
					fc->no_flock = 1;
M
Miklos Szeredi 已提交
853 854 855
			} else {
				if (!(arg->flags & FUSE_POSIX_LOCKS))
					fc->no_flock = 1;
M
Miklos Szeredi 已提交
856
			}
857 858
			if (arg->flags & FUSE_ATOMIC_O_TRUNC)
				fc->atomic_o_trunc = 1;
859 860 861 862 863
			if (arg->minor >= 9) {
				/* LOOKUP has dependency on proto version */
				if (arg->flags & FUSE_EXPORT_SUPPORT)
					fc->export_support = 1;
			}
864 865
			if (arg->flags & FUSE_BIG_WRITES)
				fc->big_writes = 1;
866 867
			if (arg->flags & FUSE_DONT_MASK)
				fc->dont_mask = 1;
868 869
			if (arg->flags & FUSE_AUTO_INVAL_DATA)
				fc->auto_inval_data = 1;
870
			if (arg->flags & FUSE_DO_READDIRPLUS) {
871
				fc->do_readdirplus = 1;
872 873 874
				if (arg->flags & FUSE_READDIRPLUS_AUTO)
					fc->readdirplus_auto = 1;
			}
875 876
			if (arg->flags & FUSE_ASYNC_DIO)
				fc->async_dio = 1;
877
		} else {
878
			ra_pages = fc->max_read / PAGE_CACHE_SIZE;
879
			fc->no_lock = 1;
M
Miklos Szeredi 已提交
880
			fc->no_flock = 1;
881
		}
882 883

		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
884 885
		fc->minor = arg->minor;
		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
886
		fc->max_write = max_t(unsigned, 4096, fc->max_write);
887
		fc->conn_init = 1;
888
	}
M
Maxim Patlasov 已提交
889
	fc->initialized = 1;
890
	wake_up_all(&fc->blocked_waitq);
891 892
}

893
static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
894 895
{
	struct fuse_init_in *arg = &req->misc.init_in;
M
Miklos Szeredi 已提交
896

897 898
	arg->major = FUSE_KERNEL_VERSION;
	arg->minor = FUSE_KERNEL_MINOR_VERSION;
899
	arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
900
	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
M
Miklos Szeredi 已提交
901
		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
M
Miklos Szeredi 已提交
902
		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
903
		FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
904
		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO;
905 906 907 908 909
	req->in.h.opcode = FUSE_INIT;
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(*arg);
	req->in.args[0].value = arg;
	req->out.numargs = 1;
D
Daniel Mack 已提交
910
	/* Variable length argument used for backward compatibility
911 912 913 914 915 916
	   with interface version < 7.5.  Rest of init_out is zeroed
	   by do_get_request(), so a short reply is not a problem */
	req->out.argvar = 1;
	req->out.args[0].size = sizeof(struct fuse_init_out);
	req->out.args[0].value = &req->misc.init_out;
	req->end = process_init_reply;
917
	fuse_request_send_background(fc, req);
918 919
}

T
Tejun Heo 已提交
920 921 922 923 924
static void fuse_free_conn(struct fuse_conn *fc)
{
	kfree(fc);
}

925 926 927 928
static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
{
	int err;

929
	fc->bdi.name = "fuse";
930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966
	fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
	/* fuse does it's own writeback accounting */
	fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;

	err = bdi_init(&fc->bdi);
	if (err)
		return err;

	fc->bdi_initialized = 1;

	if (sb->s_bdev) {
		err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
				    MAJOR(fc->dev), MINOR(fc->dev));
	} else {
		err = bdi_register_dev(&fc->bdi, fc->dev);
	}

	if (err)
		return err;

	/*
	 * 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(&fc->bdi, 1);

	return 0;
}

M
Miklos Szeredi 已提交
967 968 969 970 971 972
static int fuse_fill_super(struct super_block *sb, void *data, int silent)
{
	struct fuse_conn *fc;
	struct inode *root;
	struct fuse_mount_data d;
	struct file *file;
973
	struct dentry *root_dentry;
974
	struct fuse_req *init_req;
M
Miklos Szeredi 已提交
975
	int err;
M
Miklos Szeredi 已提交
976
	int is_bdev = sb->s_bdev != NULL;
M
Miklos Szeredi 已提交
977

978
	err = -EINVAL;
979
	if (sb->s_flags & MS_MANDLOCK)
980
		goto err;
981

A
Al Viro 已提交
982 983
	sb->s_flags &= ~MS_NOSEC;

M
Miklos Szeredi 已提交
984
	if (!parse_fuse_opt((char *) data, &d, is_bdev))
985
		goto err;
M
Miklos Szeredi 已提交
986

M
Miklos Szeredi 已提交
987
	if (is_bdev) {
988
#ifdef CONFIG_BLOCK
989
		err = -EINVAL;
M
Miklos Szeredi 已提交
990
		if (!sb_set_blocksize(sb, d.blksize))
991
			goto err;
992
#endif
M
Miklos Szeredi 已提交
993 994 995 996
	} else {
		sb->s_blocksize = PAGE_CACHE_SIZE;
		sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	}
M
Miklos Szeredi 已提交
997 998 999
	sb->s_magic = FUSE_SUPER_MAGIC;
	sb->s_op = &fuse_super_operations;
	sb->s_maxbytes = MAX_LFS_FILESIZE;
1000
	sb->s_time_gran = 1;
M
Miklos Szeredi 已提交
1001
	sb->s_export_op = &fuse_export_operations;
M
Miklos Szeredi 已提交
1002 1003

	file = fget(d.fd);
1004
	err = -EINVAL;
M
Miklos Szeredi 已提交
1005
	if (!file)
1006
		goto err;
M
Miklos Szeredi 已提交
1007

1008 1009
	if ((file->f_op != &fuse_dev_operations) ||
	    (file->f_cred->user_ns != &init_user_ns))
1010
		goto err_fput;
M
Miklos Szeredi 已提交
1011

1012
	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1013 1014 1015
	err = -ENOMEM;
	if (!fc)
		goto err_fput;
M
Miklos Szeredi 已提交
1016

1017 1018 1019
	fuse_conn_init(fc);

	fc->dev = sb->s_dev;
J
John Muir 已提交
1020
	fc->sb = sb;
1021 1022 1023
	err = fuse_bdi_init(fc, sb);
	if (err)
		goto err_put_conn;
1024

J
Jens Axboe 已提交
1025 1026
	sb->s_bdi = &fc->bdi;

1027 1028 1029 1030 1031
	/* Handle umasking inside the fuse code */
	if (sb->s_flags & MS_POSIXACL)
		fc->dont_mask = 1;
	sb->s_flags |= MS_POSIXACL;

T
Tejun Heo 已提交
1032
	fc->release = fuse_free_conn;
M
Miklos Szeredi 已提交
1033
	fc->flags = d.flags;
M
Miklos Szeredi 已提交
1034
	fc->user_id = d.user_id;
1035
	fc->group_id = d.group_id;
1036
	fc->max_read = max_t(unsigned, 4096, d.max_read);
M
Miklos Szeredi 已提交
1037

1038 1039 1040
	/* Used by get_root_inode() */
	sb->s_fs_info = fc;

M
Miklos Szeredi 已提交
1041
	err = -ENOMEM;
1042
	root = fuse_get_root_inode(sb, d.rootmode);
1043 1044
	root_dentry = d_make_root(root);
	if (!root_dentry)
1045
		goto err_put_conn;
A
Al Viro 已提交
1046 1047
	/* only now - we want root dentry with NULL ->d_op */
	sb->s_d_op = &fuse_dentry_operations;
1048

1049
	init_req = fuse_request_alloc(0);
1050 1051
	if (!init_req)
		goto err_put_root;
1052
	init_req->background = 1;
1053

1054
	if (is_bdev) {
1055
		fc->destroy_req = fuse_request_alloc(0);
1056
		if (!fc->destroy_req)
J
Julia Lawall 已提交
1057
			goto err_free_init_req;
1058 1059
	}

1060
	mutex_lock(&fuse_mutex);
1061 1062
	err = -EINVAL;
	if (file->private_data)
1063
		goto err_unlock;
1064

1065 1066 1067 1068 1069
	err = fuse_ctl_add_conn(fc);
	if (err)
		goto err_unlock;

	list_add_tail(&fc->entry, &fuse_conn_list);
1070 1071
	sb->s_root = root_dentry;
	fc->connected = 1;
1072 1073
	file->private_data = fuse_conn_get(fc);
	mutex_unlock(&fuse_mutex);
M
Miklos Szeredi 已提交
1074 1075 1076 1077 1078 1079
	/*
	 * 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);
1080

1081
	fuse_send_init(fc, init_req);
1082

M
Miklos Szeredi 已提交
1083 1084
	return 0;

1085 1086
 err_unlock:
	mutex_unlock(&fuse_mutex);
J
Julia Lawall 已提交
1087
 err_free_init_req:
1088
	fuse_request_free(init_req);
1089 1090
 err_put_root:
	dput(root_dentry);
1091
 err_put_conn:
1092
	fuse_bdi_destroy(fc);
1093
	fuse_conn_put(fc);
1094 1095 1096
 err_fput:
	fput(file);
 err:
M
Miklos Szeredi 已提交
1097 1098 1099
	return err;
}

A
Al Viro 已提交
1100
static struct dentry *fuse_mount(struct file_system_type *fs_type,
1101
		       int flags, const char *dev_name,
A
Al Viro 已提交
1102
		       void *raw_data)
M
Miklos Szeredi 已提交
1103
{
A
Al Viro 已提交
1104
	return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
M
Miklos Szeredi 已提交
1105 1106
}

J
John Muir 已提交
1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119
static void fuse_kill_sb_anon(struct super_block *sb)
{
	struct fuse_conn *fc = get_fuse_conn_super(sb);

	if (fc) {
		down_write(&fc->killsb);
		fc->sb = NULL;
		up_write(&fc->killsb);
	}

	kill_anon_super(sb);
}

1120 1121 1122
static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
M
Miklos Szeredi 已提交
1123
	.fs_flags	= FS_HAS_SUBTYPE,
A
Al Viro 已提交
1124
	.mount		= fuse_mount,
J
John Muir 已提交
1125
	.kill_sb	= fuse_kill_sb_anon,
1126
};
1127
MODULE_ALIAS_FS("fuse");
1128 1129

#ifdef CONFIG_BLOCK
A
Al Viro 已提交
1130
static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1131
			   int flags, const char *dev_name,
A
Al Viro 已提交
1132
			   void *raw_data)
1133
{
A
Al Viro 已提交
1134
	return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1135 1136
}

J
John Muir 已提交
1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149
static void fuse_kill_sb_blk(struct super_block *sb)
{
	struct fuse_conn *fc = get_fuse_conn_super(sb);

	if (fc) {
		down_write(&fc->killsb);
		fc->sb = NULL;
		up_write(&fc->killsb);
	}

	kill_block_super(sb);
}

1150 1151 1152
static struct file_system_type fuseblk_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuseblk",
A
Al Viro 已提交
1153
	.mount		= fuse_mount_blk,
J
John Muir 已提交
1154
	.kill_sb	= fuse_kill_sb_blk,
A
Alexey Dobriyan 已提交
1155
	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1156
};
1157
MODULE_ALIAS_FS("fuseblk");
1158

1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178
static inline int register_fuseblk(void)
{
	return register_filesystem(&fuseblk_fs_type);
}

static inline void unregister_fuseblk(void)
{
	unregister_filesystem(&fuseblk_fs_type);
}
#else
static inline int register_fuseblk(void)
{
	return 0;
}

static inline void unregister_fuseblk(void)
{
}
#endif

1179
static void fuse_inode_init_once(void *foo)
M
Miklos Szeredi 已提交
1180
{
M
Miklos Szeredi 已提交
1181
	struct inode *inode = foo;
M
Miklos Szeredi 已提交
1182

C
Christoph Lameter 已提交
1183
	inode_init_once(inode);
M
Miklos Szeredi 已提交
1184 1185 1186 1187 1188 1189
}

static int __init fuse_fs_init(void)
{
	int err;

1190 1191 1192
	fuse_inode_cachep = kmem_cache_create("fuse_inode",
					      sizeof(struct fuse_inode),
					      0, SLAB_HWCACHE_ALIGN,
1193
					      fuse_inode_init_once);
1194 1195
	err = -ENOMEM;
	if (!fuse_inode_cachep)
1196 1197 1198 1199 1200 1201 1202 1203 1204
		goto out;

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

	err = register_filesystem(&fuse_fs_type);
	if (err)
		goto out3;
1205 1206

	return 0;
M
Miklos Szeredi 已提交
1207

1208
 out3:
1209
	unregister_fuseblk();
1210 1211
 out2:
	kmem_cache_destroy(fuse_inode_cachep);
1212
 out:
M
Miklos Szeredi 已提交
1213 1214 1215 1216 1217 1218
	return err;
}

static void fuse_fs_cleanup(void)
{
	unregister_filesystem(&fuse_fs_type);
1219
	unregister_fuseblk();
1220 1221 1222 1223 1224 1225

	/*
	 * Make sure all delayed rcu free inodes are flushed before we
	 * destroy cache.
	 */
	rcu_barrier();
M
Miklos Szeredi 已提交
1226 1227 1228
	kmem_cache_destroy(fuse_inode_cachep);
}

1229 1230 1231
static struct kobject *fuse_kobj;
static struct kobject *connections_kobj;

1232 1233 1234 1235
static int fuse_sysfs_init(void)
{
	int err;

1236
	fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1237 1238
	if (!fuse_kobj) {
		err = -ENOMEM;
1239
		goto out_err;
1240
	}
1241

1242 1243 1244
	connections_kobj = kobject_create_and_add("connections", fuse_kobj);
	if (!connections_kobj) {
		err = -ENOMEM;
1245
		goto out_fuse_unregister;
1246
	}
1247 1248 1249 1250

	return 0;

 out_fuse_unregister:
1251
	kobject_put(fuse_kobj);
1252 1253 1254 1255 1256 1257
 out_err:
	return err;
}

static void fuse_sysfs_cleanup(void)
{
1258 1259
	kobject_put(connections_kobj);
	kobject_put(fuse_kobj);
1260 1261
}

M
Miklos Szeredi 已提交
1262 1263 1264 1265
static int __init fuse_init(void)
{
	int res;

M
Miklos Szeredi 已提交
1266
	printk(KERN_INFO "fuse init (API version %i.%i)\n",
M
Miklos Szeredi 已提交
1267 1268
	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);

1269
	INIT_LIST_HEAD(&fuse_conn_list);
M
Miklos Szeredi 已提交
1270 1271 1272 1273
	res = fuse_fs_init();
	if (res)
		goto err;

M
Miklos Szeredi 已提交
1274 1275 1276 1277
	res = fuse_dev_init();
	if (res)
		goto err_fs_cleanup;

1278 1279 1280 1281
	res = fuse_sysfs_init();
	if (res)
		goto err_dev_cleanup;

1282 1283 1284 1285
	res = fuse_ctl_init();
	if (res)
		goto err_sysfs_cleanup;

1286 1287 1288
	sanitize_global_limit(&max_user_bgreq);
	sanitize_global_limit(&max_user_congthresh);

M
Miklos Szeredi 已提交
1289 1290
	return 0;

1291 1292
 err_sysfs_cleanup:
	fuse_sysfs_cleanup();
1293 1294
 err_dev_cleanup:
	fuse_dev_cleanup();
M
Miklos Szeredi 已提交
1295 1296
 err_fs_cleanup:
	fuse_fs_cleanup();
M
Miklos Szeredi 已提交
1297 1298 1299 1300 1301 1302 1303 1304
 err:
	return res;
}

static void __exit fuse_exit(void)
{
	printk(KERN_DEBUG "fuse exit\n");

1305
	fuse_ctl_cleanup();
1306
	fuse_sysfs_cleanup();
M
Miklos Szeredi 已提交
1307
	fuse_fs_cleanup();
M
Miklos Szeredi 已提交
1308
	fuse_dev_cleanup();
M
Miklos Szeredi 已提交
1309 1310 1311 1312
}

module_init(fuse_init);
module_exit(fuse_exit);