file.c 61.2 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/kernel.h>
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#include <linux/sched.h>
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#include <linux/module.h>
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#include <linux/compat.h>
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#include <linux/swap.h>
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static const struct file_operations fuse_direct_io_file_operations;
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static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
			  int opcode, struct fuse_open_out *outargp)
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{
	struct fuse_open_in inarg;
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	struct fuse_req *req;
	int err;

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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(&inarg, 0, sizeof(inarg));
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	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
	if (!fc->atomic_o_trunc)
		inarg.flags &= ~O_TRUNC;
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	req->in.h.opcode = opcode;
	req->in.h.nodeid = nodeid;
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	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(*outargp);
	req->out.args[0].value = outargp;
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	fuse_request_send(fc, req);
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	err = req->out.h.error;
	fuse_put_request(fc, req);

	return err;
}

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struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
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{
	struct fuse_file *ff;
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	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
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	if (unlikely(!ff))
		return NULL;

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	ff->fc = fc;
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	ff->reserved_req = fuse_request_alloc(0);
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	if (unlikely(!ff->reserved_req)) {
		kfree(ff);
		return NULL;
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	}
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	INIT_LIST_HEAD(&ff->write_entry);
	atomic_set(&ff->count, 0);
	RB_CLEAR_NODE(&ff->polled_node);
	init_waitqueue_head(&ff->poll_wait);

	spin_lock(&fc->lock);
	ff->kh = ++fc->khctr;
	spin_unlock(&fc->lock);

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	return ff;
}

void fuse_file_free(struct fuse_file *ff)
{
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	fuse_request_free(ff->reserved_req);
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	kfree(ff);
}

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struct fuse_file *fuse_file_get(struct fuse_file *ff)
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{
	atomic_inc(&ff->count);
	return ff;
}

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static void fuse_release_async(struct work_struct *work)
{
	struct fuse_req *req;
	struct fuse_conn *fc;
	struct path path;

	req = container_of(work, struct fuse_req, misc.release.work);
	path = req->misc.release.path;
	fc = get_fuse_conn(path.dentry->d_inode);

	fuse_put_request(fc, req);
	path_put(&path);
}

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static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
{
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	if (fc->destroy_req) {
		/*
		 * If this is a fuseblk mount, then it's possible that
		 * releasing the path will result in releasing the
		 * super block and sending the DESTROY request.  If
		 * the server is single threaded, this would hang.
		 * For this reason do the path_put() in a separate
		 * thread.
		 */
		atomic_inc(&req->count);
		INIT_WORK(&req->misc.release.work, fuse_release_async);
		schedule_work(&req->misc.release.work);
	} else {
		path_put(&req->misc.release.path);
	}
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}

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static void fuse_file_put(struct fuse_file *ff, bool sync)
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{
	if (atomic_dec_and_test(&ff->count)) {
		struct fuse_req *req = ff->reserved_req;
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		if (sync) {
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			req->background = 0;
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			fuse_request_send(ff->fc, req);
			path_put(&req->misc.release.path);
			fuse_put_request(ff->fc, req);
		} else {
			req->end = fuse_release_end;
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			req->background = 1;
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			fuse_request_send_background(ff->fc, req);
		}
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		kfree(ff);
	}
}

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int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
		 bool isdir)
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{
	struct fuse_open_out outarg;
	struct fuse_file *ff;
	int err;
	int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;

	ff = fuse_file_alloc(fc);
	if (!ff)
		return -ENOMEM;

	err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
	if (err) {
		fuse_file_free(ff);
		return err;
	}

	if (isdir)
		outarg.open_flags &= ~FOPEN_DIRECT_IO;

	ff->fh = outarg.fh;
	ff->nodeid = nodeid;
	ff->open_flags = outarg.open_flags;
	file->private_data = fuse_file_get(ff);

	return 0;
}
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EXPORT_SYMBOL_GPL(fuse_do_open);
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void fuse_finish_open(struct inode *inode, struct file *file)
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{
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	struct fuse_file *ff = file->private_data;
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	struct fuse_conn *fc = get_fuse_conn(inode);
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	if (ff->open_flags & FOPEN_DIRECT_IO)
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		file->f_op = &fuse_direct_io_file_operations;
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	if (!(ff->open_flags & FOPEN_KEEP_CACHE))
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		invalidate_inode_pages2(inode->i_mapping);
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	if (ff->open_flags & FOPEN_NONSEEKABLE)
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		nonseekable_open(inode, file);
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	if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
		struct fuse_inode *fi = get_fuse_inode(inode);

		spin_lock(&fc->lock);
		fi->attr_version = ++fc->attr_version;
		i_size_write(inode, 0);
		spin_unlock(&fc->lock);
		fuse_invalidate_attr(inode);
	}
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}

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int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
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{
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	struct fuse_conn *fc = get_fuse_conn(inode);
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	int err;

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

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	err = fuse_do_open(fc, get_node_id(inode), file, isdir);
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	if (err)
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		return err;
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	fuse_finish_open(inode, file);

	return 0;
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}

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static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
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{
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	struct fuse_conn *fc = ff->fc;
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	struct fuse_req *req = ff->reserved_req;
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	struct fuse_release_in *inarg = &req->misc.release.in;
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	spin_lock(&fc->lock);
	list_del(&ff->write_entry);
	if (!RB_EMPTY_NODE(&ff->polled_node))
		rb_erase(&ff->polled_node, &fc->polled_files);
	spin_unlock(&fc->lock);

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	wake_up_interruptible_all(&ff->poll_wait);
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	inarg->fh = ff->fh;
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	inarg->flags = flags;
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	req->in.h.opcode = opcode;
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	req->in.h.nodeid = ff->nodeid;
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	req->in.numargs = 1;
	req->in.args[0].size = sizeof(struct fuse_release_in);
	req->in.args[0].value = inarg;
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}

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void fuse_release_common(struct file *file, int opcode)
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{
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	struct fuse_file *ff;
	struct fuse_req *req;
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	ff = file->private_data;
	if (unlikely(!ff))
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		return;
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	req = ff->reserved_req;
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	fuse_prepare_release(ff, file->f_flags, opcode);
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	if (ff->flock) {
		struct fuse_release_in *inarg = &req->misc.release.in;
		inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
		inarg->lock_owner = fuse_lock_owner_id(ff->fc,
						       (fl_owner_t) file);
	}
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	/* Hold vfsmount and dentry until release is finished */
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	path_get(&file->f_path);
	req->misc.release.path = file->f_path;
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	/*
	 * Normally this will send the RELEASE request, however if
	 * some asynchronous READ or WRITE requests are outstanding,
	 * the sending will be delayed.
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	 *
	 * 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.
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	 */
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	fuse_file_put(ff, ff->fc->destroy_req != NULL);
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}

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static int fuse_open(struct inode *inode, struct file *file)
{
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	return fuse_open_common(inode, file, false);
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}

static int fuse_release(struct inode *inode, struct file *file)
{
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	fuse_release_common(file, FUSE_RELEASE);

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

void fuse_sync_release(struct fuse_file *ff, int flags)
{
	WARN_ON(atomic_read(&ff->count) > 1);
	fuse_prepare_release(ff, flags, FUSE_RELEASE);
	ff->reserved_req->force = 1;
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	ff->reserved_req->background = 0;
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	fuse_request_send(ff->fc, ff->reserved_req);
	fuse_put_request(ff->fc, ff->reserved_req);
	kfree(ff);
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}
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EXPORT_SYMBOL_GPL(fuse_sync_release);
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/*
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 * Scramble the ID space with XTEA, so that the value of the files_struct
 * pointer is not exposed to userspace.
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 */
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u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
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{
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	u32 *k = fc->scramble_key;
	u64 v = (unsigned long) id;
	u32 v0 = v;
	u32 v1 = v >> 32;
	u32 sum = 0;
	int i;

	for (i = 0; i < 32; i++) {
		v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
		sum += 0x9E3779B9;
		v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
	}

	return (u64) v0 + ((u64) v1 << 32);
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}

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/*
 * Check if page is under writeback
 *
 * This is currently done by walking the list of writepage requests
 * for the inode, which can be pretty inefficient.
 */
static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct fuse_req *req;
	bool found = false;

	spin_lock(&fc->lock);
	list_for_each_entry(req, &fi->writepages, writepages_entry) {
		pgoff_t curr_index;

		BUG_ON(req->inode != inode);
		curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
		if (curr_index == index) {
			found = true;
			break;
		}
	}
	spin_unlock(&fc->lock);

	return found;
}

/*
 * Wait for page writeback to be completed.
 *
 * Since fuse doesn't rely on the VM writeback tracking, this has to
 * use some other means.
 */
static int 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));
	return 0;
}

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static int fuse_flush(struct file *file, fl_owner_t id)
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{
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	struct inode *inode = file_inode(file);
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	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_req *req;
	struct fuse_flush_in inarg;
	int err;

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	if (is_bad_inode(inode))
		return -EIO;

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	if (fc->no_flush)
		return 0;

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	req = fuse_get_req_nofail_nopages(fc, file);
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	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
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	inarg.lock_owner = fuse_lock_owner_id(fc, id);
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	req->in.h.opcode = FUSE_FLUSH;
	req->in.h.nodeid = get_node_id(inode);
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
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	req->force = 1;
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	fuse_request_send(fc, req);
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	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (err == -ENOSYS) {
		fc->no_flush = 1;
		err = 0;
	}
	return err;
}

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/*
 * Wait for all pending writepages on the inode to finish.
 *
 * This is currently done by blocking further writes with FUSE_NOWRITE
 * and waiting for all sent writes to complete.
 *
 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
 * could conflict with truncation.
 */
static void fuse_sync_writes(struct inode *inode)
{
	fuse_set_nowrite(inode);
	fuse_release_nowrite(inode);
}

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int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
		      int datasync, int isdir)
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{
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	struct inode *inode = file->f_mapping->host;
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	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_req *req;
	struct fuse_fsync_in inarg;
	int err;

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	if (is_bad_inode(inode))
		return -EIO;

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	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
	if (err)
		return err;

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	if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
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		return 0;

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	mutex_lock(&inode->i_mutex);

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	/*
	 * Start writeback against all dirty pages of the inode, then
	 * wait for all outstanding writes, before sending the FSYNC
	 * request.
	 */
	err = write_inode_now(inode, 0);
	if (err)
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		goto out;
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	fuse_sync_writes(inode);

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	req = fuse_get_req_nopages(fc);
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	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto out;
	}
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	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
	inarg.fsync_flags = datasync ? 1 : 0;
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	req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
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	req->in.h.nodeid = get_node_id(inode);
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
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	fuse_request_send(fc, req);
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	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (err == -ENOSYS) {
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		if (isdir)
			fc->no_fsyncdir = 1;
		else
			fc->no_fsync = 1;
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		err = 0;
	}
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out:
	mutex_unlock(&inode->i_mutex);
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	return err;
}

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static int fuse_fsync(struct file *file, loff_t start, loff_t end,
		      int datasync)
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{
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	return fuse_fsync_common(file, start, end, datasync, 0);
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}

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void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
		    size_t count, int opcode)
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{
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	struct fuse_read_in *inarg = &req->misc.read.in;
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	struct fuse_file *ff = file->private_data;
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	inarg->fh = ff->fh;
	inarg->offset = pos;
	inarg->size = count;
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	inarg->flags = file->f_flags;
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	req->in.h.opcode = opcode;
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	req->in.h.nodeid = ff->nodeid;
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	req->in.numargs = 1;
	req->in.args[0].size = sizeof(struct fuse_read_in);
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	req->in.args[0].value = inarg;
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	req->out.argvar = 1;
	req->out.numargs = 1;
	req->out.args[0].size = count;
}

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static void fuse_release_user_pages(struct fuse_req *req, int write)
{
	unsigned i;

	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];
		if (write)
			set_page_dirty_lock(page);
		put_page(page);
	}
}

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/**
 * In case of short read, the caller sets 'pos' to the position of
 * actual end of fuse request in IO request. Otherwise, if bytes_requested
 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
 *
 * An example:
 * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
 * both submitted asynchronously. The first of them was ACKed by userspace as
 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
 * second request was ACKed as short, e.g. only 1K was read, resulting in
 * pos == 33K.
 *
 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
 * will be equal to the length of the longest contiguous fragment of
 * transferred data starting from the beginning of IO request.
 */
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;
	spin_unlock(&io->lock);

	if (!left) {
		long res;

		if (io->err)
			res = io->err;
		else if (io->bytes >= 0 && io->write)
			res = -EIO;
		else {
			res = io->bytes < 0 ? io->size : io->bytes;

			if (!is_sync_kiocb(io->iocb)) {
				struct path *path = &io->iocb->ki_filp->f_path;
				struct inode *inode = path->dentry->d_inode;
				struct fuse_conn *fc = get_fuse_conn(inode);
				struct fuse_inode *fi = get_fuse_inode(inode);

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

		aio_complete(io->iocb, res, 0);
		kfree(io);
	}
}

static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
{
	struct fuse_io_priv *io = req->io;
	ssize_t pos = -1;

	fuse_release_user_pages(req, !io->write);

	if (io->write) {
		if (req->misc.write.in.size != req->misc.write.out.size)
			pos = req->misc.write.in.offset - io->offset +
				req->misc.write.out.size;
	} else {
		if (req->misc.read.in.size != req->out.args[0].size)
			pos = req->misc.read.in.offset - io->offset +
				req->out.args[0].size;
	}

	fuse_aio_complete(io, req->out.h.error, pos);
}

static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
		size_t num_bytes, struct fuse_io_priv *io)
{
	spin_lock(&io->lock);
	io->size += num_bytes;
	io->reqs++;
	spin_unlock(&io->lock);

	req->io = io;
	req->end = fuse_aio_complete_req;

596
	__fuse_get_request(req);
M
Maxim Patlasov 已提交
597 598 599 600 601
	fuse_request_send_background(fc, req);

	return num_bytes;
}

602
static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
603
			     loff_t pos, size_t count, fl_owner_t owner)
604
{
605
	struct file *file = io->file;
606 607
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
608

609
	fuse_read_fill(req, file, pos, count, FUSE_READ);
610
	if (owner != NULL) {
611
		struct fuse_read_in *inarg = &req->misc.read.in;
612 613 614 615

		inarg->read_flags |= FUSE_READ_LOCKOWNER;
		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
	}
616 617 618 619

	if (io->async)
		return fuse_async_req_send(fc, req, count, io);

620
	fuse_request_send(fc, req);
621
	return req->out.args[0].size;
622 623
}

624 625 626 627 628 629 630 631 632 633 634 635 636 637
static void fuse_read_update_size(struct inode *inode, loff_t size,
				  u64 attr_ver)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);

	spin_lock(&fc->lock);
	if (attr_ver == fi->attr_version && size < inode->i_size) {
		fi->attr_version = ++fc->attr_version;
		i_size_write(inode, size);
	}
	spin_unlock(&fc->lock);
}

M
Miklos Szeredi 已提交
638 639
static int fuse_readpage(struct file *file, struct page *page)
{
640
	struct fuse_io_priv io = { .async = 0, .file = file };
M
Miklos Szeredi 已提交
641 642
	struct inode *inode = page->mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
643
	struct fuse_req *req;
644 645 646 647
	size_t num_read;
	loff_t pos = page_offset(page);
	size_t count = PAGE_CACHE_SIZE;
	u64 attr_ver;
648 649 650 651 652 653
	int err;

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

M
Miklos Szeredi 已提交
654
	/*
L
Lucas De Marchi 已提交
655
	 * Page writeback can extend beyond the lifetime of the
M
Miklos Szeredi 已提交
656 657 658 659 660
	 * page-cache page, so make sure we read a properly synced
	 * page.
	 */
	fuse_wait_on_page_writeback(inode, page->index);

M
Maxim Patlasov 已提交
661
	req = fuse_get_req(fc, 1);
662 663
	err = PTR_ERR(req);
	if (IS_ERR(req))
M
Miklos Szeredi 已提交
664 665
		goto out;

666 667
	attr_ver = fuse_get_attr_version(fc);

M
Miklos Szeredi 已提交
668
	req->out.page_zeroing = 1;
669
	req->out.argpages = 1;
M
Miklos Szeredi 已提交
670 671
	req->num_pages = 1;
	req->pages[0] = page;
672
	req->page_descs[0].length = count;
673
	num_read = fuse_send_read(req, &io, pos, count, NULL);
M
Miklos Szeredi 已提交
674 675
	err = req->out.h.error;
	fuse_put_request(fc, req);
676 677 678 679 680 681 682 683

	if (!err) {
		/*
		 * Short read means EOF.  If file size is larger, truncate it
		 */
		if (num_read < count)
			fuse_read_update_size(inode, pos + num_read, attr_ver);

M
Miklos Szeredi 已提交
684
		SetPageUptodate(page);
685 686
	}

687
	fuse_invalidate_attr(inode); /* atime changed */
M
Miklos Szeredi 已提交
688 689 690 691 692
 out:
	unlock_page(page);
	return err;
}

693
static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
694
{
695
	int i;
696 697
	size_t count = req->misc.read.in.size;
	size_t num_read = req->out.args[0].size;
698
	struct address_space *mapping = NULL;
699

700 701
	for (i = 0; mapping == NULL && i < req->num_pages; i++)
		mapping = req->pages[i]->mapping;
702

703 704 705 706 707 708 709 710 711 712 713 714 715 716 717
	if (mapping) {
		struct inode *inode = mapping->host;

		/*
		 * Short read means EOF. If file size is larger, truncate it
		 */
		if (!req->out.h.error && num_read < count) {
			loff_t pos;

			pos = page_offset(req->pages[0]) + num_read;
			fuse_read_update_size(inode, pos,
					      req->misc.read.attr_ver);
		}
		fuse_invalidate_attr(inode); /* atime changed */
	}
718

719 720 721 722
	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];
		if (!req->out.h.error)
			SetPageUptodate(page);
723 724
		else
			SetPageError(page);
725
		unlock_page(page);
726
		page_cache_release(page);
727
	}
728
	if (req->ff)
729
		fuse_file_put(req->ff, false);
730 731
}

732
static void fuse_send_readpages(struct fuse_req *req, struct file *file)
733
{
734 735
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
736 737
	loff_t pos = page_offset(req->pages[0]);
	size_t count = req->num_pages << PAGE_CACHE_SHIFT;
738 739

	req->out.argpages = 1;
740
	req->out.page_zeroing = 1;
741
	req->out.page_replace = 1;
742
	fuse_read_fill(req, file, pos, count, FUSE_READ);
743
	req->misc.read.attr_ver = fuse_get_attr_version(fc);
744
	if (fc->async_read) {
745
		req->ff = fuse_file_get(ff);
746
		req->end = fuse_readpages_end;
747
		fuse_request_send_background(fc, req);
748
	} else {
749
		fuse_request_send(fc, req);
750
		fuse_readpages_end(fc, req);
751
		fuse_put_request(fc, req);
752
	}
753 754
}

755
struct fuse_fill_data {
756
	struct fuse_req *req;
757
	struct file *file;
758
	struct inode *inode;
M
Maxim Patlasov 已提交
759
	unsigned nr_pages;
760 761 762 763
};

static int fuse_readpages_fill(void *_data, struct page *page)
{
764
	struct fuse_fill_data *data = _data;
765 766 767 768
	struct fuse_req *req = data->req;
	struct inode *inode = data->inode;
	struct fuse_conn *fc = get_fuse_conn(inode);

M
Miklos Szeredi 已提交
769 770
	fuse_wait_on_page_writeback(inode, page->index);

771 772 773 774
	if (req->num_pages &&
	    (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {
M
Maxim Patlasov 已提交
775 776
		int nr_alloc = min_t(unsigned, data->nr_pages,
				     FUSE_MAX_PAGES_PER_REQ);
777
		fuse_send_readpages(req, data->file);
778 779 780 781 782 783
		if (fc->async_read)
			req = fuse_get_req_for_background(fc, nr_alloc);
		else
			req = fuse_get_req(fc, nr_alloc);

		data->req = req;
784
		if (IS_ERR(req)) {
785
			unlock_page(page);
786
			return PTR_ERR(req);
787 788
		}
	}
M
Maxim Patlasov 已提交
789 790 791 792 793 794

	if (WARN_ON(req->num_pages >= req->max_pages)) {
		fuse_put_request(fc, req);
		return -EIO;
	}

795
	page_cache_get(page);
796
	req->pages[req->num_pages] = page;
797
	req->page_descs[req->num_pages].length = PAGE_SIZE;
M
Miklos Szeredi 已提交
798
	req->num_pages++;
M
Maxim Patlasov 已提交
799
	data->nr_pages--;
800 801 802 803 804 805 806 807
	return 0;
}

static int fuse_readpages(struct file *file, struct address_space *mapping,
			  struct list_head *pages, unsigned nr_pages)
{
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
808
	struct fuse_fill_data data;
809
	int err;
M
Maxim Patlasov 已提交
810
	int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
811

812
	err = -EIO;
813
	if (is_bad_inode(inode))
814
		goto out;
815

816
	data.file = file;
817
	data.inode = inode;
818 819 820 821
	if (fc->async_read)
		data.req = fuse_get_req_for_background(fc, nr_alloc);
	else
		data.req = fuse_get_req(fc, nr_alloc);
M
Maxim Patlasov 已提交
822
	data.nr_pages = nr_pages;
823
	err = PTR_ERR(data.req);
824
	if (IS_ERR(data.req))
825
		goto out;
826 827

	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
828 829
	if (!err) {
		if (data.req->num_pages)
830
			fuse_send_readpages(data.req, file);
831 832 833
		else
			fuse_put_request(fc, data.req);
	}
834
out:
835
	return err;
836 837
}

M
Miklos Szeredi 已提交
838 839 840 841
static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
				  unsigned long nr_segs, loff_t pos)
{
	struct inode *inode = iocb->ki_filp->f_mapping->host;
842
	struct fuse_conn *fc = get_fuse_conn(inode);
M
Miklos Szeredi 已提交
843

844 845 846 847 848 849 850
	/*
	 * In auto invalidate mode, always update attributes on read.
	 * Otherwise, only update if we attempt to read past EOF (to ensure
	 * i_size is up to date).
	 */
	if (fc->auto_inval_data ||
	    (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
M
Miklos Szeredi 已提交
851 852 853 854 855 856 857 858 859
		int err;
		err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
		if (err)
			return err;
	}

	return generic_file_aio_read(iocb, iov, nr_segs, pos);
}

860
static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
861
			    loff_t pos, size_t count)
M
Miklos Szeredi 已提交
862
{
863 864
	struct fuse_write_in *inarg = &req->misc.write.in;
	struct fuse_write_out *outarg = &req->misc.write.out;
M
Miklos Szeredi 已提交
865

866 867 868
	inarg->fh = ff->fh;
	inarg->offset = pos;
	inarg->size = count;
M
Miklos Szeredi 已提交
869
	req->in.h.opcode = FUSE_WRITE;
870
	req->in.h.nodeid = ff->nodeid;
M
Miklos Szeredi 已提交
871
	req->in.numargs = 2;
872
	if (ff->fc->minor < 9)
873 874 875
		req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
	else
		req->in.args[0].size = sizeof(struct fuse_write_in);
876
	req->in.args[0].value = inarg;
M
Miklos Szeredi 已提交
877 878 879
	req->in.args[1].size = count;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(struct fuse_write_out);
880 881 882
	req->out.args[0].value = outarg;
}

883
static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
884
			      loff_t pos, size_t count, fl_owner_t owner)
885
{
886
	struct file *file = io->file;
887 888
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
889 890
	struct fuse_write_in *inarg = &req->misc.write.in;

891
	fuse_write_fill(req, ff, pos, count);
892
	inarg->flags = file->f_flags;
893 894 895 896
	if (owner != NULL) {
		inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
	}
897 898 899 900

	if (io->async)
		return fuse_async_req_send(fc, req, count, io);

901
	fuse_request_send(fc, req);
902
	return req->misc.write.out.size;
M
Miklos Szeredi 已提交
903 904
}

M
Miklos Szeredi 已提交
905
void fuse_write_update_size(struct inode *inode, loff_t pos)
906 907 908 909 910 911 912 913 914 915 916
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);

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

N
Nick Piggin 已提交
917 918 919 920 921 922 923
static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
				    struct inode *inode, loff_t pos,
				    size_t count)
{
	size_t res;
	unsigned offset;
	unsigned i;
924
	struct fuse_io_priv io = { .async = 0, .file = file };
N
Nick Piggin 已提交
925 926 927 928

	for (i = 0; i < req->num_pages; i++)
		fuse_wait_on_page_writeback(inode, req->pages[i]->index);

929
	res = fuse_send_write(req, &io, pos, count, NULL);
N
Nick Piggin 已提交
930

931
	offset = req->page_descs[0].offset;
N
Nick Piggin 已提交
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
	count = res;
	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];

		if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
			SetPageUptodate(page);

		if (count > PAGE_CACHE_SIZE - offset)
			count -= PAGE_CACHE_SIZE - offset;
		else
			count = 0;
		offset = 0;

		unlock_page(page);
		page_cache_release(page);
	}

	return res;
}

static ssize_t fuse_fill_write_pages(struct fuse_req *req,
			       struct address_space *mapping,
			       struct iov_iter *ii, loff_t pos)
{
	struct fuse_conn *fc = get_fuse_conn(mapping->host);
	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
	size_t count = 0;
	int err;

961
	req->in.argpages = 1;
962
	req->page_descs[0].offset = offset;
N
Nick Piggin 已提交
963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978

	do {
		size_t tmp;
		struct page *page;
		pgoff_t index = pos >> PAGE_CACHE_SHIFT;
		size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
				     iov_iter_count(ii));

		bytes = min_t(size_t, bytes, fc->max_write - count);

 again:
		err = -EFAULT;
		if (iov_iter_fault_in_readable(ii, bytes))
			break;

		err = -ENOMEM;
979
		page = grab_cache_page_write_begin(mapping, index, 0);
N
Nick Piggin 已提交
980 981 982
		if (!page)
			break;

983 984 985
		if (mapping_writably_mapped(mapping))
			flush_dcache_page(page);

N
Nick Piggin 已提交
986 987 988 989 990
		pagefault_disable();
		tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
		pagefault_enable();
		flush_dcache_page(page);

991 992
		mark_page_accessed(page);

N
Nick Piggin 已提交
993 994 995 996 997 998 999 1000 1001
		if (!tmp) {
			unlock_page(page);
			page_cache_release(page);
			bytes = min(bytes, iov_iter_single_seg_count(ii));
			goto again;
		}

		err = 0;
		req->pages[req->num_pages] = page;
1002
		req->page_descs[req->num_pages].length = tmp;
N
Nick Piggin 已提交
1003 1004 1005 1006 1007 1008 1009 1010 1011
		req->num_pages++;

		iov_iter_advance(ii, tmp);
		count += tmp;
		pos += tmp;
		offset += tmp;
		if (offset == PAGE_CACHE_SIZE)
			offset = 0;

1012 1013
		if (!fc->big_writes)
			break;
N
Nick Piggin 已提交
1014
	} while (iov_iter_count(ii) && count < fc->max_write &&
1015
		 req->num_pages < req->max_pages && offset == 0);
N
Nick Piggin 已提交
1016 1017 1018 1019

	return count > 0 ? count : err;
}

1020 1021 1022 1023 1024 1025 1026 1027
static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
{
	return min_t(unsigned,
		     ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
		     (pos >> PAGE_CACHE_SHIFT) + 1,
		     FUSE_MAX_PAGES_PER_REQ);
}

N
Nick Piggin 已提交
1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
static ssize_t fuse_perform_write(struct file *file,
				  struct address_space *mapping,
				  struct iov_iter *ii, loff_t pos)
{
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	int err = 0;
	ssize_t res = 0;

	if (is_bad_inode(inode))
		return -EIO;

	do {
		struct fuse_req *req;
		ssize_t count;
1043
		unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
N
Nick Piggin 已提交
1044

1045
		req = fuse_get_req(fc, nr_pages);
N
Nick Piggin 已提交
1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085
		if (IS_ERR(req)) {
			err = PTR_ERR(req);
			break;
		}

		count = fuse_fill_write_pages(req, mapping, ii, pos);
		if (count <= 0) {
			err = count;
		} else {
			size_t num_written;

			num_written = fuse_send_write_pages(req, file, inode,
							    pos, count);
			err = req->out.h.error;
			if (!err) {
				res += num_written;
				pos += num_written;

				/* break out of the loop on short write */
				if (num_written != count)
					err = -EIO;
			}
		}
		fuse_put_request(fc, req);
	} while (!err && iov_iter_count(ii));

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

	fuse_invalidate_attr(inode);

	return res > 0 ? res : err;
}

static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
				   unsigned long nr_segs, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	struct address_space *mapping = file->f_mapping;
	size_t count = 0;
A
Anand Avati 已提交
1086
	size_t ocount = 0;
N
Nick Piggin 已提交
1087
	ssize_t written = 0;
A
Anand Avati 已提交
1088
	ssize_t written_buffered = 0;
N
Nick Piggin 已提交
1089 1090 1091
	struct inode *inode = mapping->host;
	ssize_t err;
	struct iov_iter i;
A
Anand Avati 已提交
1092
	loff_t endbyte = 0;
N
Nick Piggin 已提交
1093 1094 1095

	WARN_ON(iocb->ki_pos != pos);

A
Anand Avati 已提交
1096 1097
	ocount = 0;
	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
N
Nick Piggin 已提交
1098 1099 1100
	if (err)
		return err;

A
Anand Avati 已提交
1101
	count = ocount;
1102
	sb_start_write(inode->i_sb);
N
Nick Piggin 已提交
1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114
	mutex_lock(&inode->i_mutex);

	/* We can write back this queue in page reclaim */
	current->backing_dev_info = mapping->backing_dev_info;

	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
	if (err)
		goto out;

	if (count == 0)
		goto out;

1115
	err = file_remove_suid(file);
N
Nick Piggin 已提交
1116 1117 1118
	if (err)
		goto out;

1119 1120 1121
	err = file_update_time(file);
	if (err)
		goto out;
N
Nick Piggin 已提交
1122

A
Anand Avati 已提交
1123 1124 1125 1126 1127 1128 1129 1130 1131
	if (file->f_flags & O_DIRECT) {
		written = generic_file_direct_write(iocb, iov, &nr_segs,
						    pos, &iocb->ki_pos,
						    count, ocount);
		if (written < 0 || written == count)
			goto out;

		pos += written;
		count -= written;
N
Nick Piggin 已提交
1132

A
Anand Avati 已提交
1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157
		iov_iter_init(&i, iov, nr_segs, count, written);
		written_buffered = fuse_perform_write(file, mapping, &i, pos);
		if (written_buffered < 0) {
			err = written_buffered;
			goto out;
		}
		endbyte = pos + written_buffered - 1;

		err = filemap_write_and_wait_range(file->f_mapping, pos,
						   endbyte);
		if (err)
			goto out;

		invalidate_mapping_pages(file->f_mapping,
					 pos >> PAGE_CACHE_SHIFT,
					 endbyte >> PAGE_CACHE_SHIFT);

		written += written_buffered;
		iocb->ki_pos = pos + written_buffered;
	} else {
		iov_iter_init(&i, iov, nr_segs, count, 0);
		written = fuse_perform_write(file, mapping, &i, pos);
		if (written >= 0)
			iocb->ki_pos = pos + written;
	}
N
Nick Piggin 已提交
1158 1159 1160
out:
	current->backing_dev_info = NULL;
	mutex_unlock(&inode->i_mutex);
1161
	sb_end_write(inode->i_sb);
N
Nick Piggin 已提交
1162 1163 1164 1165

	return written ? written : err;
}

1166 1167
static inline void fuse_page_descs_length_init(struct fuse_req *req,
		unsigned index, unsigned nr_pages)
1168 1169 1170
{
	int i;

1171
	for (i = index; i < index + nr_pages; i++)
1172 1173 1174 1175
		req->page_descs[i].length = PAGE_SIZE -
			req->page_descs[i].offset;
}

1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186
static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
{
	return (unsigned long)ii->iov->iov_base + ii->iov_offset;
}

static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
					size_t max_size)
{
	return min(iov_iter_single_seg_count(ii), max_size);
}

1187
static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1188
			       size_t *nbytesp, int write)
M
Miklos Szeredi 已提交
1189
{
1190
	size_t nbytes = 0;  /* # bytes already packed in req */
1191

1192 1193
	/* Special case for kernel I/O: can copy directly into the buffer */
	if (segment_eq(get_fs(), KERNEL_DS)) {
1194 1195 1196
		unsigned long user_addr = fuse_get_user_addr(ii);
		size_t frag_size = fuse_get_frag_size(ii, *nbytesp);

1197 1198 1199 1200 1201
		if (write)
			req->in.args[1].value = (void *) user_addr;
		else
			req->out.args[0].value = (void *) user_addr;

1202 1203
		iov_iter_advance(ii, frag_size);
		*nbytesp = frag_size;
1204 1205
		return 0;
	}
M
Miklos Szeredi 已提交
1206

1207
	while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1208 1209 1210 1211 1212
		unsigned npages;
		unsigned long user_addr = fuse_get_user_addr(ii);
		unsigned offset = user_addr & ~PAGE_MASK;
		size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
		int ret;
M
Miklos Szeredi 已提交
1213

1214
		unsigned n = req->max_pages - req->num_pages;
1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238
		frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);

		npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
		npages = clamp(npages, 1U, n);

		ret = get_user_pages_fast(user_addr, npages, !write,
					  &req->pages[req->num_pages]);
		if (ret < 0)
			return ret;

		npages = ret;
		frag_size = min_t(size_t, frag_size,
				  (npages << PAGE_SHIFT) - offset);
		iov_iter_advance(ii, frag_size);

		req->page_descs[req->num_pages].offset = offset;
		fuse_page_descs_length_init(req, req->num_pages, npages);

		req->num_pages += npages;
		req->page_descs[req->num_pages - 1].length -=
			(npages << PAGE_SHIFT) - offset - frag_size;

		nbytes += frag_size;
	}
1239 1240 1241 1242 1243 1244

	if (write)
		req->in.argpages = 1;
	else
		req->out.argpages = 1;

1245
	*nbytesp = nbytes;
1246

M
Miklos Szeredi 已提交
1247 1248 1249
	return 0;
}

1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266
static inline int fuse_iter_npages(const struct iov_iter *ii_p)
{
	struct iov_iter ii = *ii_p;
	int npages = 0;

	while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
		unsigned long user_addr = fuse_get_user_addr(&ii);
		unsigned offset = user_addr & ~PAGE_MASK;
		size_t frag_size = iov_iter_single_seg_count(&ii);

		npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
		iov_iter_advance(&ii, frag_size);
	}

	return min(npages, FUSE_MAX_PAGES_PER_REQ);
}

1267
ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
M
Miklos Szeredi 已提交
1268 1269
		       unsigned long nr_segs, size_t count, loff_t *ppos,
		       int write)
M
Miklos Szeredi 已提交
1270
{
1271
	struct file *file = io->file;
1272 1273
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
M
Miklos Szeredi 已提交
1274 1275 1276
	size_t nmax = write ? fc->max_write : fc->max_read;
	loff_t pos = *ppos;
	ssize_t res = 0;
1277
	struct fuse_req *req;
1278 1279 1280
	struct iov_iter ii;

	iov_iter_init(&ii, iov, nr_segs, count, 0);
1281

1282
	req = fuse_get_req(fc, fuse_iter_npages(&ii));
1283 1284
	if (IS_ERR(req))
		return PTR_ERR(req);
M
Miklos Szeredi 已提交
1285 1286 1287

	while (count) {
		size_t nres;
1288
		fl_owner_t owner = current->files;
1289
		size_t nbytes = min(count, nmax);
1290
		int err = fuse_get_user_pages(req, &ii, &nbytes, write);
M
Miklos Szeredi 已提交
1291 1292 1293 1294
		if (err) {
			res = err;
			break;
		}
1295

M
Miklos Szeredi 已提交
1296
		if (write)
1297
			nres = fuse_send_write(req, io, pos, nbytes, owner);
M
Miklos Szeredi 已提交
1298
		else
1299
			nres = fuse_send_read(req, io, pos, nbytes, owner);
1300

1301 1302
		if (!io->async)
			fuse_release_user_pages(req, !write);
M
Miklos Szeredi 已提交
1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315
		if (req->out.h.error) {
			if (!res)
				res = req->out.h.error;
			break;
		} else if (nres > nbytes) {
			res = -EIO;
			break;
		}
		count -= nres;
		res += nres;
		pos += nres;
		if (nres != nbytes)
			break;
1316 1317
		if (count) {
			fuse_put_request(fc, req);
1318
			req = fuse_get_req(fc, fuse_iter_npages(&ii));
1319 1320 1321
			if (IS_ERR(req))
				break;
		}
M
Miklos Szeredi 已提交
1322
	}
1323 1324
	if (!IS_ERR(req))
		fuse_put_request(fc, req);
1325
	if (res > 0)
M
Miklos Szeredi 已提交
1326 1327 1328 1329
		*ppos = pos;

	return res;
}
1330
EXPORT_SYMBOL_GPL(fuse_direct_io);
M
Miklos Szeredi 已提交
1331

1332 1333
static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
				  const struct iovec *iov,
1334 1335
				  unsigned long nr_segs, loff_t *ppos,
				  size_t count)
M
Miklos Szeredi 已提交
1336
{
1337
	ssize_t res;
1338
	struct file *file = io->file;
A
Al Viro 已提交
1339
	struct inode *inode = file_inode(file);
1340 1341 1342 1343

	if (is_bad_inode(inode))
		return -EIO;

1344
	res = fuse_direct_io(io, iov, nr_segs, count, ppos, 0);
1345 1346 1347 1348

	fuse_invalidate_attr(inode);

	return res;
M
Miklos Szeredi 已提交
1349 1350
}

1351 1352 1353
static ssize_t fuse_direct_read(struct file *file, char __user *buf,
				     size_t count, loff_t *ppos)
{
1354
	struct fuse_io_priv io = { .async = 0, .file = file };
M
Miklos Szeredi 已提交
1355
	struct iovec iov = { .iov_base = buf, .iov_len = count };
1356
	return __fuse_direct_read(&io, &iov, 1, ppos, count);
1357 1358
}

1359 1360
static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
				   const struct iovec *iov,
1361
				   unsigned long nr_segs, loff_t *ppos)
M
Miklos Szeredi 已提交
1362
{
1363
	struct file *file = io->file;
A
Al Viro 已提交
1364
	struct inode *inode = file_inode(file);
1365
	size_t count = iov_length(iov, nr_segs);
M
Miklos Szeredi 已提交
1366
	ssize_t res;
1367

1368
	res = generic_write_checks(file, ppos, &count, 0);
1369
	if (!res)
1370
		res = fuse_direct_io(io, iov, nr_segs, count, ppos, 1);
1371 1372 1373

	fuse_invalidate_attr(inode);

M
Miklos Szeredi 已提交
1374 1375 1376
	return res;
}

A
Anand Avati 已提交
1377 1378 1379
static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
				 size_t count, loff_t *ppos)
{
M
Miklos Szeredi 已提交
1380
	struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
A
Al Viro 已提交
1381
	struct inode *inode = file_inode(file);
A
Anand Avati 已提交
1382
	ssize_t res;
1383
	struct fuse_io_priv io = { .async = 0, .file = file };
A
Anand Avati 已提交
1384 1385 1386 1387 1388 1389

	if (is_bad_inode(inode))
		return -EIO;

	/* Don't allow parallel writes to the same file */
	mutex_lock(&inode->i_mutex);
1390
	res = __fuse_direct_write(&io, &iov, 1, ppos);
1391 1392
	if (res > 0)
		fuse_write_update_size(inode, *ppos);
A
Anand Avati 已提交
1393 1394 1395 1396 1397
	mutex_unlock(&inode->i_mutex);

	return res;
}

M
Miklos Szeredi 已提交
1398
static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
M
Miklos Szeredi 已提交
1399
{
M
Miklos Szeredi 已提交
1400
	__free_page(req->pages[0]);
1401
	fuse_file_put(req->ff, false);
M
Miklos Szeredi 已提交
1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
}

static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
{
	struct inode *inode = req->inode;
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;

	list_del(&req->writepages_entry);
	dec_bdi_stat(bdi, BDI_WRITEBACK);
	dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
	bdi_writeout_inc(bdi);
	wake_up(&fi->page_waitq);
}

/* Called under fc->lock, may release and reacquire it */
static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
M
Miklos Szeredi 已提交
1419 1420
__releases(fc->lock)
__acquires(fc->lock)
M
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1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
{
	struct fuse_inode *fi = get_fuse_inode(req->inode);
	loff_t size = i_size_read(req->inode);
	struct fuse_write_in *inarg = &req->misc.write.in;

	if (!fc->connected)
		goto out_free;

	if (inarg->offset + PAGE_CACHE_SIZE <= size) {
		inarg->size = PAGE_CACHE_SIZE;
	} else if (inarg->offset < size) {
		inarg->size = size & (PAGE_CACHE_SIZE - 1);
	} else {
		/* Got truncated off completely */
		goto out_free;
M
Miklos Szeredi 已提交
1436
	}
M
Miklos Szeredi 已提交
1437 1438 1439

	req->in.args[1].size = inarg->size;
	fi->writectr++;
1440
	fuse_request_send_background_locked(fc, req);
M
Miklos Szeredi 已提交
1441 1442 1443 1444 1445 1446
	return;

 out_free:
	fuse_writepage_finish(fc, req);
	spin_unlock(&fc->lock);
	fuse_writepage_free(fc, req);
1447
	fuse_put_request(fc, req);
M
Miklos Szeredi 已提交
1448
	spin_lock(&fc->lock);
M
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1449 1450
}

M
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1451 1452 1453 1454 1455 1456 1457
/*
 * If fi->writectr is positive (no truncate or fsync going on) send
 * all queued writepage requests.
 *
 * Called with fc->lock
 */
void fuse_flush_writepages(struct inode *inode)
M
Miklos Szeredi 已提交
1458 1459
__releases(fc->lock)
__acquires(fc->lock)
M
Miklos Szeredi 已提交
1460
{
M
Miklos Szeredi 已提交
1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct fuse_req *req;

	while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
		req = list_entry(fi->queued_writes.next, struct fuse_req, list);
		list_del_init(&req->list);
		fuse_send_writepage(fc, req);
	}
}

static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
{
	struct inode *inode = req->inode;
	struct fuse_inode *fi = get_fuse_inode(inode);

	mapping_set_error(inode->i_mapping, req->out.h.error);
	spin_lock(&fc->lock);
	fi->writectr--;
	fuse_writepage_finish(fc, req);
	spin_unlock(&fc->lock);
	fuse_writepage_free(fc, req);
}

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_req *req;
	struct fuse_file *ff;
	struct page *tmp_page;

	set_page_writeback(page);

1497
	req = fuse_request_alloc_nofs(1);
M
Miklos Szeredi 已提交
1498 1499 1500
	if (!req)
		goto err;

1501
	req->background = 1; /* writeback always goes to bg_queue */
M
Miklos Szeredi 已提交
1502 1503 1504 1505 1506 1507 1508 1509 1510 1511
	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (!tmp_page)
		goto err_free;

	spin_lock(&fc->lock);
	BUG_ON(list_empty(&fi->write_files));
	ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
	req->ff = fuse_file_get(ff);
	spin_unlock(&fc->lock);

1512
	fuse_write_fill(req, ff, page_offset(page), 0);
M
Miklos Szeredi 已提交
1513 1514

	copy_highpage(tmp_page, page);
1515
	req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1516
	req->in.argpages = 1;
M
Miklos Szeredi 已提交
1517 1518
	req->num_pages = 1;
	req->pages[0] = tmp_page;
1519
	req->page_descs[0].offset = 0;
1520
	req->page_descs[0].length = PAGE_SIZE;
M
Miklos Szeredi 已提交
1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588
	req->end = fuse_writepage_end;
	req->inode = inode;

	inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
	inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
	end_page_writeback(page);

	spin_lock(&fc->lock);
	list_add(&req->writepages_entry, &fi->writepages);
	list_add_tail(&req->list, &fi->queued_writes);
	fuse_flush_writepages(inode);
	spin_unlock(&fc->lock);

	return 0;

err_free:
	fuse_request_free(req);
err:
	end_page_writeback(page);
	return -ENOMEM;
}

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

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

	return err;
}

static int fuse_launder_page(struct page *page)
{
	int err = 0;
	if (clear_page_dirty_for_io(page)) {
		struct inode *inode = page->mapping->host;
		err = fuse_writepage_locked(page);
		if (!err)
			fuse_wait_on_page_writeback(inode, page->index);
	}
	return err;
}

/*
 * Write back dirty pages now, because there may not be any suitable
 * open files later
 */
static void fuse_vma_close(struct vm_area_struct *vma)
{
	filemap_write_and_wait(vma->vm_file->f_mapping);
}

/*
 * Wait for writeback against this page to complete before allowing it
 * to be marked dirty again, and hence written back again, possibly
 * before the previous writepage completed.
 *
 * Block here, instead of in ->writepage(), so that the userspace fs
 * can only block processes actually operating on the filesystem.
 *
 * Otherwise unprivileged userspace fs would be able to block
 * unrelated:
 *
 * - page migration
 * - sync(2)
 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
 */
1589
static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
M
Miklos Szeredi 已提交
1590
{
1591
	struct page *page = vmf->page;
M
Miklos Szeredi 已提交
1592 1593 1594 1595 1596 1597 1598 1599 1600 1601
	/*
	 * Don't use page->mapping as it may become NULL from a
	 * concurrent truncate.
	 */
	struct inode *inode = vma->vm_file->f_mapping->host;

	fuse_wait_on_page_writeback(inode, page->index);
	return 0;
}

1602
static const struct vm_operations_struct fuse_file_vm_ops = {
M
Miklos Szeredi 已提交
1603 1604 1605
	.close		= fuse_vma_close,
	.fault		= filemap_fault,
	.page_mkwrite	= fuse_page_mkwrite,
1606
	.remap_pages	= generic_file_remap_pages,
M
Miklos Szeredi 已提交
1607 1608 1609 1610 1611
};

static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
A
Al Viro 已提交
1612
		struct inode *inode = file_inode(file);
M
Miklos Szeredi 已提交
1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626
		struct fuse_conn *fc = get_fuse_conn(inode);
		struct fuse_inode *fi = get_fuse_inode(inode);
		struct fuse_file *ff = file->private_data;
		/*
		 * file may be written through mmap, so chain it onto the
		 * inodes's write_file list
		 */
		spin_lock(&fc->lock);
		if (list_empty(&ff->write_entry))
			list_add(&ff->write_entry, &fi->write_files);
		spin_unlock(&fc->lock);
	}
	file_accessed(file);
	vma->vm_ops = &fuse_file_vm_ops;
M
Miklos Szeredi 已提交
1627 1628 1629
	return 0;
}

1630 1631 1632 1633 1634 1635
static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
{
	/* Can't provide the coherency needed for MAP_SHARED */
	if (vma->vm_flags & VM_MAYSHARE)
		return -ENODEV;

1636 1637
	invalidate_inode_pages2(file->f_mapping);

1638 1639 1640
	return generic_file_mmap(file, vma);
}

1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666
static int convert_fuse_file_lock(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;
		fl->fl_pid = ffl->pid;
		break;

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

static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1667 1668
			 const struct file_lock *fl, int opcode, pid_t pid,
			 int flock)
1669
{
A
Al Viro 已提交
1670
	struct inode *inode = file_inode(file);
1671
	struct fuse_conn *fc = get_fuse_conn(inode);
1672 1673 1674 1675
	struct fuse_file *ff = file->private_data;
	struct fuse_lk_in *arg = &req->misc.lk_in;

	arg->fh = ff->fh;
1676
	arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1677 1678 1679 1680
	arg->lk.start = fl->fl_start;
	arg->lk.end = fl->fl_end;
	arg->lk.type = fl->fl_type;
	arg->lk.pid = pid;
1681 1682
	if (flock)
		arg->lk_flags |= FUSE_LK_FLOCK;
1683 1684 1685 1686 1687 1688 1689 1690 1691
	req->in.h.opcode = opcode;
	req->in.h.nodeid = get_node_id(inode);
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(*arg);
	req->in.args[0].value = arg;
}

static int fuse_getlk(struct file *file, struct file_lock *fl)
{
A
Al Viro 已提交
1692
	struct inode *inode = file_inode(file);
1693 1694 1695 1696 1697
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_req *req;
	struct fuse_lk_out outarg;
	int err;

M
Maxim Patlasov 已提交
1698
	req = fuse_get_req_nopages(fc);
1699 1700 1701
	if (IS_ERR(req))
		return PTR_ERR(req);

1702
	fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1703 1704 1705
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(outarg);
	req->out.args[0].value = &outarg;
1706
	fuse_request_send(fc, req);
1707 1708 1709 1710 1711 1712 1713 1714
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (!err)
		err = convert_fuse_file_lock(&outarg.lk, fl);

	return err;
}

1715
static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1716
{
A
Al Viro 已提交
1717
	struct inode *inode = file_inode(file);
1718 1719 1720 1721 1722 1723
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_req *req;
	int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
	pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
	int err;

J
J. Bruce Fields 已提交
1724
	if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
M
Miklos Szeredi 已提交
1725 1726 1727 1728
		/* NLM needs asynchronous locks, which we don't support yet */
		return -ENOLCK;
	}

1729 1730 1731 1732
	/* Unlock on close is handled by the flush method */
	if (fl->fl_flags & FL_CLOSE)
		return 0;

M
Maxim Patlasov 已提交
1733
	req = fuse_get_req_nopages(fc);
1734 1735 1736
	if (IS_ERR(req))
		return PTR_ERR(req);

1737
	fuse_lk_fill(req, file, fl, opcode, pid, flock);
1738
	fuse_request_send(fc, req);
1739
	err = req->out.h.error;
1740 1741 1742
	/* locking is restartable */
	if (err == -EINTR)
		err = -ERESTARTSYS;
1743 1744 1745 1746 1747 1748
	fuse_put_request(fc, req);
	return err;
}

static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
{
A
Al Viro 已提交
1749
	struct inode *inode = file_inode(file);
1750 1751 1752
	struct fuse_conn *fc = get_fuse_conn(inode);
	int err;

M
Miklos Szeredi 已提交
1753 1754 1755
	if (cmd == F_CANCELLK) {
		err = 0;
	} else if (cmd == F_GETLK) {
1756
		if (fc->no_lock) {
1757
			posix_test_lock(file, fl);
1758 1759 1760 1761 1762
			err = 0;
		} else
			err = fuse_getlk(file, fl);
	} else {
		if (fc->no_lock)
M
Miklos Szeredi 已提交
1763
			err = posix_lock_file(file, fl, NULL);
1764
		else
1765
			err = fuse_setlk(file, fl, 0);
1766 1767 1768 1769
	}
	return err;
}

1770 1771
static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
{
A
Al Viro 已提交
1772
	struct inode *inode = file_inode(file);
1773 1774 1775
	struct fuse_conn *fc = get_fuse_conn(inode);
	int err;

M
Miklos Szeredi 已提交
1776
	if (fc->no_flock) {
1777 1778
		err = flock_lock_file_wait(file, fl);
	} else {
M
Miklos Szeredi 已提交
1779 1780
		struct fuse_file *ff = file->private_data;

1781 1782
		/* emulate flock with POSIX locks */
		fl->fl_owner = (fl_owner_t) file;
M
Miklos Szeredi 已提交
1783
		ff->flock = true;
1784 1785 1786 1787 1788 1789
		err = fuse_setlk(file, fl, 1);
	}

	return err;
}

M
Miklos Szeredi 已提交
1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801
static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
{
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_req *req;
	struct fuse_bmap_in inarg;
	struct fuse_bmap_out outarg;
	int err;

	if (!inode->i_sb->s_bdev || fc->no_bmap)
		return 0;

M
Maxim Patlasov 已提交
1802
	req = fuse_get_req_nopages(fc);
M
Miklos Szeredi 已提交
1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816
	if (IS_ERR(req))
		return 0;

	memset(&inarg, 0, sizeof(inarg));
	inarg.block = block;
	inarg.blocksize = inode->i_sb->s_blocksize;
	req->in.h.opcode = FUSE_BMAP;
	req->in.h.nodeid = get_node_id(inode);
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(outarg);
	req->out.args[0].value = &outarg;
1817
	fuse_request_send(fc, req);
M
Miklos Szeredi 已提交
1818 1819 1820 1821 1822 1823 1824 1825
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (err == -ENOSYS)
		fc->no_bmap = 1;

	return err ? 0 : outarg.block;
}

1826
static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
M
Miklos Szeredi 已提交
1827 1828
{
	loff_t retval;
A
Al Viro 已提交
1829
	struct inode *inode = file_inode(file);
M
Miklos Szeredi 已提交
1830

1831
	/* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
1832 1833
	if (whence == SEEK_CUR || whence == SEEK_SET)
		return generic_file_llseek(file, offset, whence);
1834

1835 1836 1837
	mutex_lock(&inode->i_mutex);
	retval = fuse_update_attributes(inode, NULL, file, NULL);
	if (!retval)
1838
		retval = generic_file_llseek(file, offset, whence);
M
Miklos Szeredi 已提交
1839
	mutex_unlock(&inode->i_mutex);
1840

M
Miklos Szeredi 已提交
1841 1842 1843
	return retval;
}

T
Tejun Heo 已提交
1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857
static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
			unsigned int nr_segs, size_t bytes, bool to_user)
{
	struct iov_iter ii;
	int page_idx = 0;

	if (!bytes)
		return 0;

	iov_iter_init(&ii, iov, nr_segs, bytes, 0);

	while (iov_iter_count(&ii)) {
		struct page *page = pages[page_idx++];
		size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
D
Dan Carpenter 已提交
1858
		void *kaddr;
T
Tejun Heo 已提交
1859

D
Dan Carpenter 已提交
1860
		kaddr = kmap(page);
T
Tejun Heo 已提交
1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880

		while (todo) {
			char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
			size_t iov_len = ii.iov->iov_len - ii.iov_offset;
			size_t copy = min(todo, iov_len);
			size_t left;

			if (!to_user)
				left = copy_from_user(kaddr, uaddr, copy);
			else
				left = copy_to_user(uaddr, kaddr, copy);

			if (unlikely(left))
				return -EFAULT;

			iov_iter_advance(&ii, copy);
			todo -= copy;
			kaddr += copy;
		}

1881
		kunmap(page);
T
Tejun Heo 已提交
1882 1883 1884 1885 1886
	}

	return 0;
}

1887 1888 1889 1890 1891 1892
/*
 * CUSE servers compiled on 32bit broke on 64bit kernels because the
 * ABI was defined to be 'struct iovec' which is different on 32bit
 * and 64bit.  Fortunately we can determine which structure the server
 * used from the size of the reply.
 */
M
Miklos Szeredi 已提交
1893 1894 1895
static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
				     size_t transferred, unsigned count,
				     bool is_compat)
1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924
{
#ifdef CONFIG_COMPAT
	if (count * sizeof(struct compat_iovec) == transferred) {
		struct compat_iovec *ciov = src;
		unsigned i;

		/*
		 * With this interface a 32bit server cannot support
		 * non-compat (i.e. ones coming from 64bit apps) ioctl
		 * requests
		 */
		if (!is_compat)
			return -EINVAL;

		for (i = 0; i < count; i++) {
			dst[i].iov_base = compat_ptr(ciov[i].iov_base);
			dst[i].iov_len = ciov[i].iov_len;
		}
		return 0;
	}
#endif

	if (count * sizeof(struct iovec) != transferred)
		return -EIO;

	memcpy(dst, src, transferred);
	return 0;
}

M
Miklos Szeredi 已提交
1925 1926 1927 1928 1929 1930
/* Make sure iov_length() won't overflow */
static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
{
	size_t n;
	u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;

1931
	for (n = 0; n < count; n++, iov++) {
M
Miklos Szeredi 已提交
1932 1933 1934 1935 1936 1937 1938
		if (iov->iov_len > (size_t) max)
			return -ENOMEM;
		max -= iov->iov_len;
	}
	return 0;
}

M
Miklos Szeredi 已提交
1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974
static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
				 void *src, size_t transferred, unsigned count,
				 bool is_compat)
{
	unsigned i;
	struct fuse_ioctl_iovec *fiov = src;

	if (fc->minor < 16) {
		return fuse_copy_ioctl_iovec_old(dst, src, transferred,
						 count, is_compat);
	}

	if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
		return -EIO;

	for (i = 0; i < count; i++) {
		/* Did the server supply an inappropriate value? */
		if (fiov[i].base != (unsigned long) fiov[i].base ||
		    fiov[i].len != (unsigned long) fiov[i].len)
			return -EIO;

		dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
		dst[i].iov_len = (size_t) fiov[i].len;

#ifdef CONFIG_COMPAT
		if (is_compat &&
		    (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
		     (compat_size_t) dst[i].iov_len != fiov[i].len))
			return -EIO;
#endif
	}

	return 0;
}


T
Tejun Heo 已提交
1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
/*
 * For ioctls, there is no generic way to determine how much memory
 * needs to be read and/or written.  Furthermore, ioctls are allowed
 * to dereference the passed pointer, so the parameter requires deep
 * copying but FUSE has no idea whatsoever about what to copy in or
 * out.
 *
 * This is solved by allowing FUSE server to retry ioctl with
 * necessary in/out iovecs.  Let's assume the ioctl implementation
 * needs to read in the following structure.
 *
 * struct a {
 *	char	*buf;
 *	size_t	buflen;
 * }
 *
 * On the first callout to FUSE server, inarg->in_size and
 * inarg->out_size will be NULL; then, the server completes the ioctl
 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
 * the actual iov array to
 *
 * { { .iov_base = inarg.arg,	.iov_len = sizeof(struct a) } }
 *
 * which tells FUSE to copy in the requested area and retry the ioctl.
 * On the second round, the server has access to the structure and
 * from that it can tell what to look for next, so on the invocation,
 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
 *
 * { { .iov_base = inarg.arg,	.iov_len = sizeof(struct a)	},
 *   { .iov_base = a.buf,	.iov_len = a.buflen		} }
 *
 * FUSE will copy both struct a and the pointed buffer from the
 * process doing the ioctl and retry ioctl with both struct a and the
 * buffer.
 *
 * This time, FUSE server has everything it needs and completes ioctl
 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
 *
 * Copying data out works the same way.
 *
 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
 * automatically initializes in and out iovs by decoding @cmd with
 * _IOC_* macros and the server is not allowed to request RETRY.  This
 * limits ioctl data transfers to well-formed ioctls and is the forced
 * behavior for all FUSE servers.
 */
2021 2022
long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
		   unsigned int flags)
T
Tejun Heo 已提交
2023 2024
{
	struct fuse_file *ff = file->private_data;
2025
	struct fuse_conn *fc = ff->fc;
T
Tejun Heo 已提交
2026 2027 2028 2029 2030 2031 2032 2033 2034
	struct fuse_ioctl_in inarg = {
		.fh = ff->fh,
		.cmd = cmd,
		.arg = arg,
		.flags = flags
	};
	struct fuse_ioctl_out outarg;
	struct fuse_req *req = NULL;
	struct page **pages = NULL;
M
Miklos Szeredi 已提交
2035
	struct iovec *iov_page = NULL;
T
Tejun Heo 已提交
2036 2037 2038 2039 2040
	struct iovec *in_iov = NULL, *out_iov = NULL;
	unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
	size_t in_size, out_size, transferred;
	int err;

M
Miklos Szeredi 已提交
2041 2042 2043 2044 2045 2046 2047
#if BITS_PER_LONG == 32
	inarg.flags |= FUSE_IOCTL_32BIT;
#else
	if (flags & FUSE_IOCTL_COMPAT)
		inarg.flags |= FUSE_IOCTL_32BIT;
#endif

T
Tejun Heo 已提交
2048
	/* assume all the iovs returned by client always fits in a page */
M
Miklos Szeredi 已提交
2049
	BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
T
Tejun Heo 已提交
2050 2051

	err = -ENOMEM;
2052
	pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
M
Miklos Szeredi 已提交
2053
	iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
T
Tejun Heo 已提交
2054 2055 2056 2057 2058 2059 2060 2061
	if (!pages || !iov_page)
		goto out;

	/*
	 * If restricted, initialize IO parameters as encoded in @cmd.
	 * RETRY from server is not allowed.
	 */
	if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
M
Miklos Szeredi 已提交
2062
		struct iovec *iov = iov_page;
T
Tejun Heo 已提交
2063

M
Miklos Szeredi 已提交
2064
		iov->iov_base = (void __user *)arg;
T
Tejun Heo 已提交
2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099
		iov->iov_len = _IOC_SIZE(cmd);

		if (_IOC_DIR(cmd) & _IOC_WRITE) {
			in_iov = iov;
			in_iovs = 1;
		}

		if (_IOC_DIR(cmd) & _IOC_READ) {
			out_iov = iov;
			out_iovs = 1;
		}
	}

 retry:
	inarg.in_size = in_size = iov_length(in_iov, in_iovs);
	inarg.out_size = out_size = iov_length(out_iov, out_iovs);

	/*
	 * Out data can be used either for actual out data or iovs,
	 * make sure there always is at least one page.
	 */
	out_size = max_t(size_t, out_size, PAGE_SIZE);
	max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);

	/* make sure there are enough buffer pages and init request with them */
	err = -ENOMEM;
	if (max_pages > FUSE_MAX_PAGES_PER_REQ)
		goto out;
	while (num_pages < max_pages) {
		pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
		if (!pages[num_pages])
			goto out;
		num_pages++;
	}

M
Maxim Patlasov 已提交
2100
	req = fuse_get_req(fc, num_pages);
T
Tejun Heo 已提交
2101 2102 2103 2104 2105 2106 2107
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		req = NULL;
		goto out;
	}
	memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
	req->num_pages = num_pages;
2108
	fuse_page_descs_length_init(req, 0, req->num_pages);
T
Tejun Heo 已提交
2109 2110 2111

	/* okay, let's send it to the client */
	req->in.h.opcode = FUSE_IOCTL;
2112
	req->in.h.nodeid = ff->nodeid;
T
Tejun Heo 已提交
2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	if (in_size) {
		req->in.numargs++;
		req->in.args[1].size = in_size;
		req->in.argpages = 1;

		err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
					   false);
		if (err)
			goto out;
	}

	req->out.numargs = 2;
	req->out.args[0].size = sizeof(outarg);
	req->out.args[0].value = &outarg;
	req->out.args[1].size = out_size;
	req->out.argpages = 1;
	req->out.argvar = 1;

2134
	fuse_request_send(fc, req);
T
Tejun Heo 已提交
2135 2136 2137 2138 2139 2140 2141 2142 2143
	err = req->out.h.error;
	transferred = req->out.args[1].size;
	fuse_put_request(fc, req);
	req = NULL;
	if (err)
		goto out;

	/* did it ask for retry? */
	if (outarg.flags & FUSE_IOCTL_RETRY) {
M
Miklos Szeredi 已提交
2144
		void *vaddr;
T
Tejun Heo 已提交
2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163

		/* no retry if in restricted mode */
		err = -EIO;
		if (!(flags & FUSE_IOCTL_UNRESTRICTED))
			goto out;

		in_iovs = outarg.in_iovs;
		out_iovs = outarg.out_iovs;

		/*
		 * Make sure things are in boundary, separate checks
		 * are to protect against overflow.
		 */
		err = -ENOMEM;
		if (in_iovs > FUSE_IOCTL_MAX_IOV ||
		    out_iovs > FUSE_IOCTL_MAX_IOV ||
		    in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
			goto out;

2164
		vaddr = kmap_atomic(pages[0]);
M
Miklos Szeredi 已提交
2165
		err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2166 2167
					    transferred, in_iovs + out_iovs,
					    (flags & FUSE_IOCTL_COMPAT) != 0);
2168
		kunmap_atomic(vaddr);
2169 2170
		if (err)
			goto out;
T
Tejun Heo 已提交
2171

M
Miklos Szeredi 已提交
2172
		in_iov = iov_page;
T
Tejun Heo 已提交
2173 2174
		out_iov = in_iov + in_iovs;

M
Miklos Szeredi 已提交
2175 2176 2177 2178 2179 2180 2181 2182
		err = fuse_verify_ioctl_iov(in_iov, in_iovs);
		if (err)
			goto out;

		err = fuse_verify_ioctl_iov(out_iov, out_iovs);
		if (err)
			goto out;

T
Tejun Heo 已提交
2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193
		goto retry;
	}

	err = -EIO;
	if (transferred > inarg.out_size)
		goto out;

	err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
 out:
	if (req)
		fuse_put_request(fc, req);
M
Miklos Szeredi 已提交
2194
	free_page((unsigned long) iov_page);
T
Tejun Heo 已提交
2195 2196 2197 2198 2199 2200
	while (num_pages)
		__free_page(pages[--num_pages]);
	kfree(pages);

	return err ? err : outarg.result;
}
2201
EXPORT_SYMBOL_GPL(fuse_do_ioctl);
T
Tejun Heo 已提交
2202

2203 2204
long fuse_ioctl_common(struct file *file, unsigned int cmd,
		       unsigned long arg, unsigned int flags)
2205
{
A
Al Viro 已提交
2206
	struct inode *inode = file_inode(file);
2207 2208
	struct fuse_conn *fc = get_fuse_conn(inode);

2209
	if (!fuse_allow_current_process(fc))
2210 2211 2212 2213 2214 2215 2216 2217
		return -EACCES;

	if (is_bad_inode(inode))
		return -EIO;

	return fuse_do_ioctl(file, cmd, arg, flags);
}

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static long fuse_file_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
2221
	return fuse_ioctl_common(file, cmd, arg, 0);
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}

static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
				   unsigned long arg)
{
2227
	return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
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}

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/*
 * All files which have been polled are linked to RB tree
 * fuse_conn->polled_files which is indexed by kh.  Walk the tree and
 * find the matching one.
 */
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;
}

/*
 * The file is about to be polled.  Make sure it's on the polled_files
 * RB tree.  Note that files once added to the polled_files tree are
 * not removed before the file is released.  This is because a file
 * polled once is likely to be polled again.
 */
static void fuse_register_polled_file(struct fuse_conn *fc,
				      struct fuse_file *ff)
{
	spin_lock(&fc->lock);
	if (RB_EMPTY_NODE(&ff->polled_node)) {
		struct rb_node **link, *parent;

		link = fuse_find_polled_node(fc, ff->kh, &parent);
		BUG_ON(*link);
		rb_link_node(&ff->polled_node, parent, link);
		rb_insert_color(&ff->polled_node, &fc->polled_files);
	}
	spin_unlock(&fc->lock);
}

2281
unsigned fuse_file_poll(struct file *file, poll_table *wait)
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{
	struct fuse_file *ff = file->private_data;
2284
	struct fuse_conn *fc = ff->fc;
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	struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
	struct fuse_poll_out outarg;
	struct fuse_req *req;
	int err;

	if (fc->no_poll)
		return DEFAULT_POLLMASK;

	poll_wait(file, &ff->poll_wait, wait);
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	inarg.events = (__u32)poll_requested_events(wait);
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	/*
	 * Ask for notification iff there's someone waiting for it.
	 * The client may ignore the flag and always notify.
	 */
	if (waitqueue_active(&ff->poll_wait)) {
		inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
		fuse_register_polled_file(fc, ff);
	}

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	req = fuse_get_req_nopages(fc);
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	if (IS_ERR(req))
2307
		return POLLERR;
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	req->in.h.opcode = FUSE_POLL;
2310
	req->in.h.nodeid = ff->nodeid;
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	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(outarg);
	req->out.args[0].value = &outarg;
2317
	fuse_request_send(fc, req);
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	err = req->out.h.error;
	fuse_put_request(fc, req);

	if (!err)
		return outarg.revents;
	if (err == -ENOSYS) {
		fc->no_poll = 1;
		return DEFAULT_POLLMASK;
	}
	return POLLERR;
}
2329
EXPORT_SYMBOL_GPL(fuse_file_poll);
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/*
 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
 * wakes up the poll waiters.
 */
int fuse_notify_poll_wakeup(struct fuse_conn *fc,
			    struct fuse_notify_poll_wakeup_out *outarg)
{
	u64 kh = outarg->kh;
	struct rb_node **link;

	spin_lock(&fc->lock);

	link = fuse_find_polled_node(fc, kh, NULL);
	if (*link) {
		struct fuse_file *ff;

		ff = rb_entry(*link, struct fuse_file, polled_node);
		wake_up_interruptible_sync(&ff->poll_wait);
	}

	spin_unlock(&fc->lock);
	return 0;
}

2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368
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(inode, &attr, file);
}

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static ssize_t
fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
			loff_t offset, unsigned long nr_segs)
{
	ssize_t ret = 0;
2374 2375
	struct file *file = iocb->ki_filp;
	struct fuse_file *ff = file->private_data;
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	loff_t pos = 0;
2377 2378 2379
	struct inode *inode;
	loff_t i_size;
	size_t count = iov_length(iov, nr_segs);
2380
	struct fuse_io_priv *io;
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	pos = offset;
2383 2384
	inode = file->f_mapping->host;
	i_size = i_size_read(inode);
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2386 2387 2388 2389 2390 2391 2392
	/* optimization for short read */
	if (rw != WRITE && offset + count > i_size) {
		if (offset >= i_size)
			return 0;
		count = i_size - offset;
	}

2393
	io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2394 2395
	if (!io)
		return -ENOMEM;
2396 2397 2398 2399 2400 2401 2402
	spin_lock_init(&io->lock);
	io->reqs = 1;
	io->bytes = -1;
	io->size = 0;
	io->offset = offset;
	io->write = (rw == WRITE);
	io->err = 0;
2403
	io->file = file;
2404 2405
	/*
	 * By default, we want to optimize all I/Os with async request
2406
	 * submission to the client filesystem if supported.
2407
	 */
2408
	io->async = ff->fc->async_dio;
2409 2410 2411 2412 2413 2414 2415
	io->iocb = iocb;

	/*
	 * We cannot asynchronously extend the size of a file. We have no method
	 * to wait on real async I/O requests, so we must submit this request
	 * synchronously.
	 */
2416
	if (!is_sync_kiocb(iocb) && (offset + count > i_size))
2417
		io->async = false;
2418

2419
	if (rw == WRITE)
2420
		ret = __fuse_direct_write(io, iov, nr_segs, &pos);
2421
	else
2422
		ret = __fuse_direct_read(io, iov, nr_segs, &pos, count);
2423

2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435
	if (io->async) {
		fuse_aio_complete(io, ret < 0 ? ret : 0, -1);

		/* we have a non-extending, async request, so return */
		if (ret > 0 && !is_sync_kiocb(iocb))
			return -EIOCBQUEUED;

		ret = wait_on_sync_kiocb(iocb);
	} else {
		kfree(io);
	}

2436 2437 2438 2439 2440 2441
	if (rw == WRITE) {
		if (ret > 0)
			fuse_write_update_size(inode, pos);
		else if (ret < 0 && offset + count > i_size)
			fuse_do_truncate(file);
	}
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	return ret;
}

2446 2447
static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
				loff_t length)
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{
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
	struct fuse_req *req;
	struct fuse_fallocate_in inarg = {
		.fh = ff->fh,
		.offset = offset,
		.length = length,
		.mode = mode
	};
	int err;

2460 2461 2462
	if (fc->no_fallocate)
		return -EOPNOTSUPP;

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	req = fuse_get_req_nopages(fc);
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	if (IS_ERR(req))
		return PTR_ERR(req);

	req->in.h.opcode = FUSE_FALLOCATE;
	req->in.h.nodeid = ff->nodeid;
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	fuse_request_send(fc, req);
	err = req->out.h.error;
2474 2475 2476 2477
	if (err == -ENOSYS) {
		fc->no_fallocate = 1;
		err = -EOPNOTSUPP;
	}
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	fuse_put_request(fc, req);

	return err;
}

2483
static const struct file_operations fuse_file_operations = {
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	.llseek		= fuse_file_llseek,
2485
	.read		= do_sync_read,
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	.aio_read	= fuse_file_aio_read,
2487
	.write		= do_sync_write,
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	.aio_write	= fuse_file_aio_write,
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	.mmap		= fuse_file_mmap,
	.open		= fuse_open,
	.flush		= fuse_flush,
	.release	= fuse_release,
	.fsync		= fuse_fsync,
2494
	.lock		= fuse_file_lock,
2495
	.flock		= fuse_file_flock,
2496
	.splice_read	= generic_file_splice_read,
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	.unlocked_ioctl	= fuse_file_ioctl,
	.compat_ioctl	= fuse_file_compat_ioctl,
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	.poll		= fuse_file_poll,
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	.fallocate	= fuse_file_fallocate,
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};

2503
static const struct file_operations fuse_direct_io_file_operations = {
M
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	.llseek		= fuse_file_llseek,
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	.read		= fuse_direct_read,
	.write		= fuse_direct_write,
2507
	.mmap		= fuse_direct_mmap,
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	.open		= fuse_open,
	.flush		= fuse_flush,
	.release	= fuse_release,
	.fsync		= fuse_fsync,
2512
	.lock		= fuse_file_lock,
2513
	.flock		= fuse_file_flock,
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	.unlocked_ioctl	= fuse_file_ioctl,
	.compat_ioctl	= fuse_file_compat_ioctl,
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	.poll		= fuse_file_poll,
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	.fallocate	= fuse_file_fallocate,
2518
	/* no splice_read */
M
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2519 2520
};

2521
static const struct address_space_operations fuse_file_aops  = {
M
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2522
	.readpage	= fuse_readpage,
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2523 2524
	.writepage	= fuse_writepage,
	.launder_page	= fuse_launder_page,
2525
	.readpages	= fuse_readpages,
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2526
	.set_page_dirty	= __set_page_dirty_nobuffers,
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2527
	.bmap		= fuse_bmap,
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2528
	.direct_IO	= fuse_direct_IO,
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2529 2530 2531 2532
};

void fuse_init_file_inode(struct inode *inode)
{
2533 2534
	inode->i_fop = &fuse_file_operations;
	inode->i_data.a_ops = &fuse_file_aops;
M
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}