Commit message: fuse: break infinite loop in fuse_fill_write_pages()

I got a report about unkillable task eating CPU. Further
investigation shows, that the problem is in the fuse_fill_write_pages()
function. If iov's first segment has zero length, we get an infinite
loop, because we never reach iov_iter_advance() call.

Fix this by calling iov_iter_advance() before repeating an attempt to
copy data from userspace.

A similar problem is described in 124d3b7041f ("fix writev regression:
pan hanging unkillable and un-straceable"). If zero-length segmend
is followed by segment with invalid address,
iov_iter_fault_in_readable() checks only first segment (zero-length),
iov_iter_copy_from_user_atomic() skips it, fails at second and
returns zero -> goto again without skipping zero-length segment.

Patch calls iov_iter_advance() before goto again: we'll skip zero-length
segment at second iteraction and iov_iter_fault_in_readable() will detect
invalid address.

Special thanks to Konstantin Khlebnikov, who helped a lot with the commit
description.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Maxim Patlasov <mpatlasov@parallels.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Fixes: ea9b9907b82a ("fuse: implement perform_write")
Cc: <stable@vger.kernel.org>
CVE: CVE-2015-8785
CWE: CWE-399
Vulnerability description: The fuse_fill_write_pages function in fs/fuse/file.c in the Linux kernel before 4.4 allows local users to cause a denial of service (infinite loop) via a writev system call that triggers a zero length for the first segment of an iov.

Project: linux
File: file.c

static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
				  struct iov_iter *iter,
				  loff_t *ppos)
{
	ssize_t res;
	struct file *file = io->file;
	struct inode *inode = file_inode(file);

	if (is_bad_inode(inode))
		return -EIO;

	res = fuse_direct_io(io, iter, ppos, 0);

	fuse_invalidate_attr(inode);

	return res;
}

Project: linux
File: file.c

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

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

	return ff;
}

Project: linux
File: file.c

static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
{
	bool is_sync = is_sync_kiocb(io->iocb);
	int left;

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

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

	if (!left && !is_sync) {
		ssize_t res = fuse_get_res_by_io(io);

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

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

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

Project: linux
File: file.c

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);
}

Project: linux
File: file.c

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;

	__fuse_get_request(req);
	fuse_request_send_background(fc, req);

	return num_bytes;
}

Project: linux
File: file.c

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);
	FUSE_ARGS(args);
	struct fuse_bmap_in inarg;
	struct fuse_bmap_out outarg;
	int err;

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

	memset(&inarg, 0, sizeof(inarg));
	inarg.block = block;
	inarg.blocksize = inode->i_sb->s_blocksize;
	args.in.h.opcode = FUSE_BMAP;
	args.in.h.nodeid = get_node_id(inode);
	args.in.numargs = 1;
	args.in.args[0].size = sizeof(inarg);
	args.in.args[0].value = &inarg;
	args.out.numargs = 1;
	args.out.args[0].size = sizeof(outarg);
	args.out.args[0].value = &outarg;
	err = fuse_simple_request(fc, &args);
	if (err == -ENOSYS)
		fc->no_bmap = 1;

	return err ? 0 : outarg.block;
}

Project: linux
File: file.c

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;
}

Project: linux
File: file.c

static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
				     size_t transferred, unsigned count,
				     bool is_compat)
{
#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;
}

Project: linux
File: file.c

fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
{
	DECLARE_COMPLETION_ONSTACK(wait);
	ssize_t ret = 0;
	struct file *file = iocb->ki_filp;
	struct fuse_file *ff = file->private_data;
	bool async_dio = ff->fc->async_dio;
	loff_t pos = 0;
	struct inode *inode;
	loff_t i_size;
	size_t count = iov_iter_count(iter);
	struct fuse_io_priv *io;

	pos = offset;
	inode = file->f_mapping->host;
	i_size = i_size_read(inode);

	if ((iov_iter_rw(iter) == READ) && (offset > i_size))
		return 0;

	/* optimization for short read */
	if (async_dio && iov_iter_rw(iter) != WRITE && offset + count > i_size) {
		if (offset >= i_size)
			return 0;
		iov_iter_truncate(iter, fuse_round_up(i_size - offset));
		count = iov_iter_count(iter);
	}

	io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
	if (!io)
		return -ENOMEM;
	spin_lock_init(&io->lock);
	io->reqs = 1;
	io->bytes = -1;
	io->size = 0;
	io->offset = offset;
	io->write = (iov_iter_rw(iter) == WRITE);
	io->err = 0;
	io->file = file;
	/*
	 * By default, we want to optimize all I/Os with async request
	 * submission to the client filesystem if supported.
	 */
	io->async = async_dio;
	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.
	 */
	if (!is_sync_kiocb(iocb) && (offset + count > i_size) &&
	    iov_iter_rw(iter) == WRITE)
		io->async = false;

	if (io->async && is_sync_kiocb(iocb))
		io->done = &wait;

	if (iov_iter_rw(iter) == WRITE) {
		ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
		fuse_invalidate_attr(inode);
	} else {
		ret = __fuse_direct_read(io, iter, &pos);
	}

	if (io->async) {
		fuse_aio_complete(io, ret < 0 ? ret : 0, -1);

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

		wait_for_completion(&wait);
		ret = fuse_get_res_by_io(io);
	}

	kfree(io);

	if (iov_iter_rw(iter) == WRITE) {
		if (ret > 0)
			fuse_write_update_size(inode, pos);
		else if (ret < 0 && offset + count > i_size)
			fuse_do_truncate(file);
	}

	return ret;
}

Project: linux
File: file.c

ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
		       loff_t *ppos, int flags)
{
	int write = flags & FUSE_DIO_WRITE;
	int cuse = flags & FUSE_DIO_CUSE;
	struct file *file = io->file;
	struct inode *inode = file->f_mapping->host;
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
	size_t nmax = write ? fc->max_write : fc->max_read;
	loff_t pos = *ppos;
	size_t count = iov_iter_count(iter);
	pgoff_t idx_from = pos >> PAGE_CACHE_SHIFT;
	pgoff_t idx_to = (pos + count - 1) >> PAGE_CACHE_SHIFT;
	ssize_t res = 0;
	struct fuse_req *req;

	if (io->async)
		req = fuse_get_req_for_background(fc, fuse_iter_npages(iter));
	else
		req = fuse_get_req(fc, fuse_iter_npages(iter));
	if (IS_ERR(req))
		return PTR_ERR(req);

	if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
		if (!write)
			mutex_lock(&inode->i_mutex);
		fuse_sync_writes(inode);
		if (!write)
			mutex_unlock(&inode->i_mutex);
	}

	while (count) {
		size_t nres;
		fl_owner_t owner = current->files;
		size_t nbytes = min(count, nmax);
		int err = fuse_get_user_pages(req, iter, &nbytes, write);
		if (err) {
			res = err;
			break;
		}

		if (write)
			nres = fuse_send_write(req, io, pos, nbytes, owner);
		else
			nres = fuse_send_read(req, io, pos, nbytes, owner);

		if (!io->async)
			fuse_release_user_pages(req, !write);
		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;
		if (count) {
			fuse_put_request(fc, req);
			if (io->async)
				req = fuse_get_req_for_background(fc,
					fuse_iter_npages(iter));
			else
				req = fuse_get_req(fc, fuse_iter_npages(iter));
			if (IS_ERR(req))
				break;
		}
	}
	if (!IS_ERR(req))
		fuse_put_request(fc, req);
	if (res > 0)
		*ppos = pos;

	return res;
}

Project: linux
File: file.c

static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
	struct fuse_io_priv io = { .async = 0, .file = iocb->ki_filp };
	return __fuse_direct_read(&io, to, &iocb->ki_pos);
}

Project: linux
File: file.c

static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file_inode(file);
	struct fuse_io_priv io = { .async = 0, .file = file };
	ssize_t res;

	if (is_bad_inode(inode))
		return -EIO;

	/* Don't allow parallel writes to the same file */
	mutex_lock(&inode->i_mutex);
	res = generic_write_checks(iocb, from);
	if (res > 0)
		res = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE);
	fuse_invalidate_attr(inode);
	if (res > 0)
		fuse_write_update_size(inode, iocb->ki_pos);
	mutex_unlock(&inode->i_mutex);

	return res;
}

Project: linux
File: file.c

long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
		   unsigned int flags)
{
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
	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;
	struct iovec *iov_page = NULL;
	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;

#if BITS_PER_LONG == 32
	inarg.flags |= FUSE_IOCTL_32BIT;
#else
	if (flags & FUSE_IOCTL_COMPAT)
		inarg.flags |= FUSE_IOCTL_32BIT;
#endif

	/* assume all the iovs returned by client always fits in a page */
	BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);

	err = -ENOMEM;
	pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
	iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
	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)) {
		struct iovec *iov = iov_page;

		iov->iov_base = (void __user *)arg;
		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++;
	}

	req = fuse_get_req(fc, num_pages);
	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;
	fuse_page_descs_length_init(req, 0, req->num_pages);

	/* okay, let's send it to the client */
	req->in.h.opcode = FUSE_IOCTL;
	req->in.h.nodeid = ff->nodeid;
	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;

	fuse_request_send(fc, req);
	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) {
		void *vaddr;

		/* 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;

		vaddr = kmap_atomic(pages[0]);
		err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
					    transferred, in_iovs + out_iovs,
					    (flags & FUSE_IOCTL_COMPAT) != 0);
		kunmap_atomic(vaddr);
		if (err)
			goto out;

		in_iov = iov_page;
		out_iov = in_iov + in_iovs;

		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;

		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);
	free_page((unsigned long) iov_page);
	while (num_pages)
		__free_page(pages[--num_pages]);
	kfree(pages);

	return err ? err : outarg.result;
}

Project: linux
File: file.c

static int fuse_do_readpage(struct file *file, struct page *page)
{
	struct fuse_io_priv io = { .async = 0, .file = file };
	struct inode *inode = page->mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_req *req;
	size_t num_read;
	loff_t pos = page_offset(page);
	size_t count = PAGE_CACHE_SIZE;
	u64 attr_ver;
	int err;

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

	req = fuse_get_req(fc, 1);
	if (IS_ERR(req))
		return PTR_ERR(req);

	attr_ver = fuse_get_attr_version(fc);

	req->out.page_zeroing = 1;
	req->out.argpages = 1;
	req->num_pages = 1;
	req->pages[0] = page;
	req->page_descs[0].length = count;
	num_read = fuse_send_read(req, &io, pos, count, NULL);
	err = req->out.h.error;

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

		SetPageUptodate(page);
	}

	fuse_put_request(fc, req);

	return err;
}

Project: linux
File: file.c

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);
}

Project: linux
File: file.c

struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
{
	struct fuse_file *ff;

	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
	if (unlikely(!ff))
		return NULL;

	ff->fc = fc;
	ff->reserved_req = fuse_request_alloc(0);
	if (unlikely(!ff->reserved_req)) {
		kfree(ff);
		return NULL;
	}

	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);

	return ff;
}

Project: linux
File: file.c

static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
{
	struct inode *inode = file_inode(file);
	struct fuse_conn *fc = get_fuse_conn(inode);
	int err;

	if (fc->no_flock) {
		err = flock_lock_file_wait(file, fl);
	} else {
		struct fuse_file *ff = file->private_data;

		/* emulate flock with POSIX locks */
		ff->flock = true;
		err = fuse_setlk(file, fl, 1);
	}

	return err;
}

Project: linux
File: file.c

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

Project: linux
File: file.c

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

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

	mutex_lock(&inode->i_mutex);
	retval = fuse_update_attributes(inode, NULL, file, NULL);
	if (!retval)
		retval = generic_file_llseek(file, offset, whence);
	mutex_unlock(&inode->i_mutex);

	return retval;
}

Project: linux
File: file.c

static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
{
	struct inode *inode = file_inode(file);
	struct fuse_conn *fc = get_fuse_conn(inode);
	int err;

	if (cmd == F_CANCELLK) {
		err = 0;
	} else if (cmd == F_GETLK) {
		if (fc->no_lock) {
			posix_test_lock(file, fl);
			err = 0;
		} else
			err = fuse_getlk(file, fl);
	} else {
		if (fc->no_lock)
			err = posix_lock_file(file, fl, NULL);
		else
			err = fuse_setlk(file, fl, 0);
	}
	return err;
}

Project: linux
File: file.c

static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
		fuse_link_write_file(file);

	file_accessed(file);
	vma->vm_ops = &fuse_file_vm_ops;
	return 0;
}

Project: linux
File: file.c

static void fuse_file_put(struct fuse_file *ff, bool sync)
{
	if (atomic_dec_and_test(&ff->count)) {
		struct fuse_req *req = ff->reserved_req;

		if (ff->fc->no_open) {
			/*
			 * Drop the release request when client does not
			 * implement 'open'
			 */
			__clear_bit(FR_BACKGROUND, &req->flags);
			iput(req->misc.release.inode);
			fuse_put_request(ff->fc, req);
		} else if (sync) {
			__clear_bit(FR_BACKGROUND, &req->flags);
			fuse_request_send(ff->fc, req);
			iput(req->misc.release.inode);
			fuse_put_request(ff->fc, req);
		} else {
			req->end = fuse_release_end;
			__set_bit(FR_BACKGROUND, &req->flags);
			fuse_request_send_background(ff->fc, req);
		}
		kfree(ff);
	}
}

Project: linux
File: file.c

static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
	struct inode *inode = iocb->ki_filp->f_mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);

	/*
	 * 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 ||
	    (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
		int err;
		err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
		if (err)
			return err;
	}

	return generic_file_read_iter(iocb, to);
}

Project: linux
File: file.c

static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
	struct file *file = iocb->ki_filp;
	struct address_space *mapping = file->f_mapping;
	ssize_t written = 0;
	ssize_t written_buffered = 0;
	struct inode *inode = mapping->host;
	ssize_t err;
	loff_t endbyte = 0;

	if (get_fuse_conn(inode)->writeback_cache) {
		/* Update size (EOF optimization) and mode (SUID clearing) */
		err = fuse_update_attributes(mapping->host, NULL, file, NULL);
		if (err)
			return err;

		return generic_file_write_iter(iocb, from);
	}

	mutex_lock(&inode->i_mutex);

	/* We can write back this queue in page reclaim */
	current->backing_dev_info = inode_to_bdi(inode);

	err = generic_write_checks(iocb, from);
	if (err <= 0)
		goto out;

	err = file_remove_privs(file);
	if (err)
		goto out;

	err = file_update_time(file);
	if (err)
		goto out;

	if (iocb->ki_flags & IOCB_DIRECT) {
		loff_t pos = iocb->ki_pos;
		written = generic_file_direct_write(iocb, from, pos);
		if (written < 0 || !iov_iter_count(from))
			goto out;

		pos += written;

		written_buffered = fuse_perform_write(file, mapping, from, 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 {
		written = fuse_perform_write(file, mapping, from, iocb->ki_pos);
		if (written >= 0)
			iocb->ki_pos += written;
	}
out:
	current->backing_dev_info = NULL;
	mutex_unlock(&inode->i_mutex);

	return written ? written : err;
}

Project: linux
File: file.c

void fuse_finish_open(struct inode *inode, struct file *file)
{
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = get_fuse_conn(inode);

	if (ff->open_flags & FOPEN_DIRECT_IO)
		file->f_op = &fuse_direct_io_file_operations;
	if (!(ff->open_flags & FOPEN_KEEP_CACHE))
		invalidate_inode_pages2(inode->i_mapping);
	if (ff->open_flags & FOPEN_NONSEEKABLE)
		nonseekable_open(inode, file);
	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);
		if (fc->writeback_cache)
			file_update_time(file);
	}
	if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
		fuse_link_write_file(file);
}

Project: linux
File: file.c

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

Project: linux
File: file.c

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

	if (is_bad_inode(inode))
		return -EIO;

	mutex_lock(&inode->i_mutex);

	/*
	 * Start writeback against all dirty pages of the inode, then
	 * wait for all outstanding writes, before sending the FSYNC
	 * request.
	 */
	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
	if (err)
		goto out;

	fuse_sync_writes(inode);
	err = sync_inode_metadata(inode, 1);
	if (err)
		goto out;

	if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
		goto out;

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

Project: linux
File: file.c

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);
}

Project: linux
File: file.c

static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
{
	if (io->err)
		return io->err;

	if (io->bytes >= 0 && io->write)
		return -EIO;

	return io->bytes < 0 ? io->size : io->bytes;
}

Project: linux
File: file.c

static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
			       size_t *nbytesp, int write)
{
	size_t nbytes = 0;  /* # bytes already packed in req */

	/* Special case for kernel I/O: can copy directly into the buffer */
	if (ii->type & ITER_KVEC) {
		unsigned long user_addr = fuse_get_user_addr(ii);
		size_t frag_size = fuse_get_frag_size(ii, *nbytesp);

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

		iov_iter_advance(ii, frag_size);
		*nbytesp = frag_size;
		return 0;
	}

	while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
		unsigned npages;
		size_t start;
		ssize_t ret = iov_iter_get_pages(ii,
					&req->pages[req->num_pages],
					*nbytesp - nbytes,
					req->max_pages - req->num_pages,
					&start);
		if (ret < 0)
			return ret;

		iov_iter_advance(ii, ret);
		nbytes += ret;

		ret += start;
		npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;

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

		req->num_pages += npages;
		req->page_descs[req->num_pages - 1].length -=
			(PAGE_SIZE - ret) & (PAGE_SIZE - 1);
	}

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

	*nbytesp = nbytes;

	return 0;
}

Project: linux
File: file.c

static int fuse_getlk(struct file *file, struct file_lock *fl)
{
	struct inode *inode = file_inode(file);
	struct fuse_conn *fc = get_fuse_conn(inode);
	FUSE_ARGS(args);
	struct fuse_lk_in inarg;
	struct fuse_lk_out outarg;
	int err;

	fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
	args.out.numargs = 1;
	args.out.args[0].size = sizeof(outarg);
	args.out.args[0].value = &outarg;
	err = fuse_simple_request(fc, &args);
	if (!err)
		err = convert_fuse_file_lock(&outarg.lk, fl);

	return err;
}

Project: linux
File: file.c

long fuse_ioctl_common(struct file *file, unsigned int cmd,
		       unsigned long arg, unsigned int flags)
{
	struct inode *inode = file_inode(file);
	struct fuse_conn *fc = get_fuse_conn(inode);

	if (!fuse_allow_current_process(fc))
		return -EACCES;

	if (is_bad_inode(inode))
		return -EIO;

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

Project: linux
File: file.c

static inline int fuse_iter_npages(const struct iov_iter *ii_p)
{
	return iov_iter_npages(ii_p, FUSE_MAX_PAGES_PER_REQ);
}

Project: linux
File: file.c

static void fuse_link_write_file(struct file *file)
{
	struct inode *inode = file_inode(file);
	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);
}

Project: linux
File: file.c

static void fuse_lk_fill(struct fuse_args *args, struct file *file,
			 const struct file_lock *fl, int opcode, pid_t pid,
			 int flock, struct fuse_lk_in *inarg)
{
	struct inode *inode = file_inode(file);
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;

	memset(inarg, 0, sizeof(*inarg));
	inarg->fh = ff->fh;
	inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
	inarg->lk.start = fl->fl_start;
	inarg->lk.end = fl->fl_end;
	inarg->lk.type = fl->fl_type;
	inarg->lk.pid = pid;
	if (flock)
		inarg->lk_flags |= FUSE_LK_FLOCK;
	args->in.h.opcode = opcode;
	args->in.h.nodeid = get_node_id(inode);
	args->in.numargs = 1;
	args->in.args[0].size = sizeof(*inarg);
	args->in.args[0].value = inarg;
}

Project: linux
File: file.c

int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	int err;
	bool lock_inode = (file->f_flags & O_TRUNC) &&
			  fc->atomic_o_trunc &&
			  fc->writeback_cache;

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

	if (lock_inode)
		mutex_lock(&inode->i_mutex);

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

	if (!err)
		fuse_finish_open(inode, file);

	if (lock_inode)
		mutex_unlock(&inode->i_mutex);

	return err;
}

Project: linux
File: file.c

static inline void fuse_page_descs_length_init(struct fuse_req *req,
		unsigned index, unsigned nr_pages)
{
	int i;

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

Project: linux
File: file.c

static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
{
	return fuse_range_is_writeback(inode, index, index);
}

Project: linux
File: file.c

static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct page *page = vmf->page;
	struct inode *inode = file_inode(vma->vm_file);

	file_update_time(vma->vm_file);
	lock_page(page);
	if (page->mapping != inode->i_mapping) {
		unlock_page(page);
		return VM_FAULT_NOPAGE;
	}

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

Project: linux
File: file.c

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);
	struct fuse_inode *fi = get_fuse_inode(inode);
	int err = 0;
	ssize_t res = 0;

	if (is_bad_inode(inode))
		return -EIO;

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

	do {
		struct fuse_req *req;
		ssize_t count;
		unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));

		req = fuse_get_req(fc, nr_pages);
		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);

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

	return res > 0 ? res : err;
}

Project: linux
File: file.c

static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
{
	struct fuse_conn *fc = ff->fc;
	struct fuse_req *req = ff->reserved_req;
	struct fuse_release_in *inarg = &req->misc.release.in;

	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);

	wake_up_interruptible_all(&ff->poll_wait);

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

Project: linux
File: file.c

static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
				   pgoff_t idx_to)
{
	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 (idx_from < curr_index + req->num_pages &&
		    curr_index <= idx_to) {
			found = true;
			break;
		}
	}
	spin_unlock(&fc->lock);

	return found;
}

Project: linux
File: file.c

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 &&
	    !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
		fi->attr_version = ++fc->attr_version;
		i_size_write(inode, size);
	}
	spin_unlock(&fc->lock);
}

Project: linux
File: file.c

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

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

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

Project: linux
File: file.c

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);
	struct fuse_fill_data data;
	int err;
	int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);

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

	data.file = file;
	data.inode = inode;
	if (fc->async_read)
		data.req = fuse_get_req_for_background(fc, nr_alloc);
	else
		data.req = fuse_get_req(fc, nr_alloc);
	data.nr_pages = nr_pages;
	err = PTR_ERR(data.req);
	if (IS_ERR(data.req))
		goto out;

	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
	if (!err) {
		if (data.req->num_pages)
			fuse_send_readpages(data.req, file);
		else
			fuse_put_request(fc, data.req);
	}
out:
	return err;
}

Project: linux
File: file.c

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

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

	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)
			fuse_short_read(req, inode, req->misc.read.attr_ver);

		fuse_invalidate_atime(inode);
	}

	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];
		if (!req->out.h.error)
			SetPageUptodate(page);
		else
			SetPageError(page);
		unlock_page(page);
		page_cache_release(page);
	}
	if (req->ff)
		fuse_file_put(req->ff, false);
}

Project: linux
File: file.c

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

	fuse_wait_on_page_writeback(inode, page->index);

	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)) {
		int nr_alloc = min_t(unsigned, data->nr_pages,
				     FUSE_MAX_PAGES_PER_REQ);
		fuse_send_readpages(req, data->file);
		if (fc->async_read)
			req = fuse_get_req_for_background(fc, nr_alloc);
		else
			req = fuse_get_req(fc, nr_alloc);

		data->req = req;
		if (IS_ERR(req)) {
			unlock_page(page);
			return PTR_ERR(req);
		}
	}

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

	page_cache_get(page);
	req->pages[req->num_pages] = page;
	req->page_descs[req->num_pages].length = PAGE_SIZE;
	req->num_pages++;
	data->nr_pages--;
	return 0;
}

Project: linux
File: file.c

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, *uninitialized_var(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);
}

Project: linux
File: file.c

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

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

	fuse_release_common(file, FUSE_RELEASE);

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

Project: linux
File: file.c

void fuse_release_common(struct file *file, int opcode)
{
	struct fuse_file *ff;
	struct fuse_req *req;

	ff = file->private_data;
	if (unlikely(!ff))
		return;

	req = ff->reserved_req;
	fuse_prepare_release(ff, file->f_flags, opcode);

	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);
	}
	/* Hold inode until release is finished */
	req->misc.release.inode = igrab(file_inode(file));

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

Project: linux
File: file.c

static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
{
	iput(req->misc.release.inode);
}

Project: linux
File: file.c

static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
			  int opcode, struct fuse_open_out *outargp)
{
	struct fuse_open_in inarg;
	FUSE_ARGS(args);

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

	return fuse_simple_request(fc, &args);
}

Project: linux
File: file.c

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

	fuse_read_fill(req, file, pos, count, FUSE_READ);
	if (owner != NULL) {
		struct fuse_read_in *inarg = &req->misc.read.in;

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

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

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

Project: linux
File: file.c

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

	fuse_write_fill(req, ff, pos, count);
	inarg->flags = file->f_flags;
	if (owner != NULL) {
		inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
	}

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

	fuse_request_send(fc, req);
	return req->misc.write.out.size;
}

Project: linux
File: file.c

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;
	struct fuse_io_priv io = { .async = 0, .file = file };

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

	res = fuse_send_write(req, &io, pos, count, NULL);

	offset = req->page_descs[0].offset;
	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;
}

Project: linux
File: file.c

static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
{
	struct inode *inode = file_inode(file);
	struct fuse_conn *fc = get_fuse_conn(inode);
	FUSE_ARGS(args);
	struct fuse_lk_in inarg;
	int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
	pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
	int err;

	if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
		/* NLM needs asynchronous locks, which we don't support yet */
		return -ENOLCK;
	}

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

	fuse_lk_fill(&args, file, fl, opcode, pid, flock, &inarg);
	err = fuse_simple_request(fc, &args);

	/* locking is restartable */
	if (err == -EINTR)
		err = -ERESTARTSYS;

	return err;
}

Project: linux
File: file.c

static void fuse_short_read(struct fuse_req *req, struct inode *inode,
			    u64 attr_ver)
{
	size_t num_read = req->out.args[0].size;
	struct fuse_conn *fc = get_fuse_conn(inode);

	if (fc->writeback_cache) {
		/*
		 * A hole in a file. Some data after the hole are in page cache,
		 * but have not reached the client fs yet. So, the hole is not
		 * present there.
		 */
		int i;
		int start_idx = num_read >> PAGE_CACHE_SHIFT;
		size_t off = num_read & (PAGE_CACHE_SIZE - 1);

		for (i = start_idx; i < req->num_pages; i++) {
			zero_user_segment(req->pages[i], off, PAGE_CACHE_SIZE);
			off = 0;
		}
	} else {
		loff_t pos = page_offset(req->pages[0]) + num_read;
		fuse_read_update_size(inode, pos, attr_ver);
	}
}

Project: linux
File: file.c

static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
{
	size_t n;
	u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;

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

Project: linux
File: file.c

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);
}

Project: linux
File: file.c

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

	WARN_ON(!fc->writeback_cache);

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

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

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

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

Project: linux
File: file.c

static int fuse_write_end(struct file *file, struct address_space *mapping,
		loff_t pos, unsigned len, unsigned copied,
		struct page *page, void *fsdata)
{
	struct inode *inode = page->mapping->host;

	if (!PageUptodate(page)) {
		/* Zero any unwritten bytes at the end of the page */
		size_t endoff = (pos + copied) & ~PAGE_CACHE_MASK;
		if (endoff)
			zero_user_segment(page, endoff, PAGE_CACHE_SIZE);
		SetPageUptodate(page);
	}

	fuse_write_update_size(inode, pos + copied);
	set_page_dirty(page);
	unlock_page(page);
	page_cache_release(page);

	return copied;
}

Project: linux
File: file.c

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

Project: linux
File: file.c

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

	ff = __fuse_write_file_get(fc, fi);
	err = fuse_flush_times(inode, ff);
	if (ff)
		fuse_file_put(ff, 0);

	return err;
}

Project: linux
File: file.c

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

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

	return ret;
}

Project: linux
File: file.c

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

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

		redirty_page_for_writepage(wbc, page);
		return 0;
	}

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

	return err;
}

Project: linux
File: file.c

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);
	while (req->misc.write.next) {
		struct fuse_conn *fc = get_fuse_conn(inode);
		struct fuse_write_in *inarg = &req->misc.write.in;
		struct fuse_req *next = req->misc.write.next;
		req->misc.write.next = next->misc.write.next;
		next->misc.write.next = NULL;
		next->ff = fuse_file_get(req->ff);
		list_add(&next->writepages_entry, &fi->writepages);

		/*
		 * Skip fuse_flush_writepages() to make it easy to crop requests
		 * based on primary request size.
		 *
		 * 1st case (trivial): there are no concurrent activities using
		 * fuse_set/release_nowrite.  Then we're on safe side because
		 * fuse_flush_writepages() would call fuse_send_writepage()
		 * anyway.
		 *
		 * 2nd case: someone called fuse_set_nowrite and it is waiting
		 * now for completion of all in-flight requests.  This happens
		 * rarely and no more than once per page, so this should be
		 * okay.
		 *
		 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
		 * of fuse_set_nowrite..fuse_release_nowrite section.  The fact
		 * that fuse_set_nowrite returned implies that all in-flight
		 * requests were completed along with all of their secondary
		 * requests.  Further primary requests are blocked by negative
		 * writectr.  Hence there cannot be any in-flight requests and
		 * no invocations of fuse_writepage_end() while we're in
		 * fuse_set_nowrite..fuse_release_nowrite section.
		 */
		fuse_send_writepage(fc, next, inarg->offset + inarg->size);
	}
	fi->writectr--;
	fuse_writepage_finish(fc, req);
	spin_unlock(&fc->lock);
	fuse_writepage_free(fc, req);
}

Project: linux
File: file.c

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_to_bdi(inode);
	int i;

	list_del(&req->writepages_entry);
	for (i = 0; i < req->num_pages; i++) {
		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
		dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP);
		wb_writeout_inc(&bdi->wb);
	}
	wake_up(&fi->page_waitq);
}

Project: linux
File: file.c

static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
{
	int i;

	for (i = 0; i < req->num_pages; i++)
		__free_page(req->pages[i]);

	if (req->ff)
		fuse_file_put(req->ff, false);
}

Project: linux
File: file.c

static bool fuse_writepage_in_flight(struct fuse_req *new_req,
				     struct page *page)
{
	struct fuse_conn *fc = get_fuse_conn(new_req->inode);
	struct fuse_inode *fi = get_fuse_inode(new_req->inode);
	struct fuse_req *tmp;
	struct fuse_req *old_req;
	bool found = false;
	pgoff_t curr_index;

	BUG_ON(new_req->num_pages != 0);

	spin_lock(&fc->lock);
	list_del(&new_req->writepages_entry);
	list_for_each_entry(old_req, &fi->writepages, writepages_entry) {
		BUG_ON(old_req->inode != new_req->inode);
		curr_index = old_req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
		if (curr_index <= page->index &&
		    page->index < curr_index + old_req->num_pages) {
			found = true;
			break;
		}
	}
	if (!found) {
		list_add(&new_req->writepages_entry, &fi->writepages);
		goto out_unlock;
	}

	new_req->num_pages = 1;
	for (tmp = old_req; tmp != NULL; tmp = tmp->misc.write.next) {
		BUG_ON(tmp->inode != new_req->inode);
		curr_index = tmp->misc.write.in.offset >> PAGE_CACHE_SHIFT;
		if (tmp->num_pages == 1 &&
		    curr_index == page->index) {
			old_req = tmp;
		}
	}

	if (old_req->num_pages == 1 && test_bit(FR_PENDING, &old_req->flags)) {
		struct backing_dev_info *bdi = inode_to_bdi(page->mapping->host);

		copy_highpage(old_req->pages[0], page);
		spin_unlock(&fc->lock);

		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
		dec_zone_page_state(page, NR_WRITEBACK_TEMP);
		wb_writeout_inc(&bdi->wb);
		fuse_writepage_free(fc, new_req);
		fuse_request_free(new_req);
		goto out;
	} else {
		new_req->misc.write.next = old_req->misc.write.next;
		old_req->misc.write.next = new_req;
	}
out_unlock:
	spin_unlock(&fc->lock);
out:
	return found;
}

Project: linux
File: file.c

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 page *tmp_page;
	int error = -ENOMEM;

	set_page_writeback(page);

	req = fuse_request_alloc_nofs(1);
	if (!req)
		goto err;

	/* writeback always goes to bg_queue */
	__set_bit(FR_BACKGROUND, &req->flags);
	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (!tmp_page)
		goto err_free;

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

	fuse_write_fill(req, req->ff, page_offset(page), 0);

	copy_highpage(tmp_page, page);
	req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
	req->misc.write.next = NULL;
	req->in.argpages = 1;
	req->num_pages = 1;
	req->pages[0] = tmp_page;
	req->page_descs[0].offset = 0;
	req->page_descs[0].length = PAGE_SIZE;
	req->end = fuse_writepage_end;
	req->inode = inode;

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

	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);

	end_page_writeback(page);

	return 0;

err_nofile:
	__free_page(tmp_page);
err_free:
	fuse_request_free(req);
err:
	end_page_writeback(page);
	return error;
}

Project: linux
File: file.c

static int fuse_writepages(struct address_space *mapping,
			   struct writeback_control *wbc)
{
	struct inode *inode = mapping->host;
	struct fuse_fill_wb_data data;
	int err;

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

	data.inode = inode;
	data.req = NULL;
	data.ff = NULL;

	err = -ENOMEM;
	data.orig_pages = kcalloc(FUSE_MAX_PAGES_PER_REQ,
				  sizeof(struct page *),
				  GFP_NOFS);
	if (!data.orig_pages)
		goto out;

	err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
	if (data.req) {
		/* Ignore errors if we can write at least one page */
		BUG_ON(!data.req->num_pages);
		fuse_writepages_send(&data);
		err = 0;
	}
	if (data.ff)
		fuse_file_put(data.ff, false);

	kfree(data.orig_pages);
out:
	return err;
}

Project: linux
File: file.c

static int fuse_writepages_fill(struct page *page,
		struct writeback_control *wbc, void *_data)
{
	struct fuse_fill_wb_data *data = _data;
	struct fuse_req *req = data->req;
	struct inode *inode = data->inode;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct page *tmp_page;
	bool is_writeback;
	int err;

	if (!data->ff) {
		err = -EIO;
		data->ff = fuse_write_file_get(fc, get_fuse_inode(inode));
		if (!data->ff)
			goto out_unlock;
	}

	/*
	 * Being under writeback is unlikely but possible.  For example direct
	 * read to an mmaped fuse file will set the page dirty twice; once when
	 * the pages are faulted with get_user_pages(), and then after the read
	 * completed.
	 */
	is_writeback = fuse_page_is_writeback(inode, page->index);

	if (req && req->num_pages &&
	    (is_writeback || req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_write ||
	     data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) {
		fuse_writepages_send(data);
		data->req = NULL;
	}
	err = -ENOMEM;
	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (!tmp_page)
		goto out_unlock;

	/*
	 * The page must not be redirtied until the writeout is completed
	 * (i.e. userspace has sent a reply to the write request).  Otherwise
	 * there could be more than one temporary page instance for each real
	 * page.
	 *
	 * This is ensured by holding the page lock in page_mkwrite() while
	 * checking fuse_page_is_writeback().  We already hold the page lock
	 * since clear_page_dirty_for_io() and keep it held until we add the
	 * request to the fi->writepages list and increment req->num_pages.
	 * After this fuse_page_is_writeback() will indicate that the page is
	 * under writeback, so we can release the page lock.
	 */
	if (data->req == NULL) {
		struct fuse_inode *fi = get_fuse_inode(inode);

		err = -ENOMEM;
		req = fuse_request_alloc_nofs(FUSE_MAX_PAGES_PER_REQ);
		if (!req) {
			__free_page(tmp_page);
			goto out_unlock;
		}

		fuse_write_fill(req, data->ff, page_offset(page), 0);
		req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
		req->misc.write.next = NULL;
		req->in.argpages = 1;
		__set_bit(FR_BACKGROUND, &req->flags);
		req->num_pages = 0;
		req->end = fuse_writepage_end;
		req->inode = inode;

		spin_lock(&fc->lock);
		list_add(&req->writepages_entry, &fi->writepages);
		spin_unlock(&fc->lock);

		data->req = req;
	}
	set_page_writeback(page);

	copy_highpage(tmp_page, page);
	req->pages[req->num_pages] = tmp_page;
	req->page_descs[req->num_pages].offset = 0;
	req->page_descs[req->num_pages].length = PAGE_SIZE;

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

	err = 0;
	if (is_writeback && fuse_writepage_in_flight(req, page)) {
		end_page_writeback(page);
		data->req = NULL;
		goto out_unlock;
	}
	data->orig_pages[req->num_pages] = page;

	/*
	 * Protected by fc->lock against concurrent access by
	 * fuse_page_is_writeback().
	 */
	spin_lock(&fc->lock);
	req->num_pages++;
	spin_unlock(&fc->lock);

out_unlock:
	unlock_page(page);

	return err;
}

Project: linux
File: file.c

static void fuse_writepages_send(struct fuse_fill_wb_data *data)
{
	struct fuse_req *req = data->req;
	struct inode *inode = data->inode;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	int num_pages = req->num_pages;
	int i;

	req->ff = fuse_file_get(data->ff);
	spin_lock(&fc->lock);
	list_add_tail(&req->list, &fi->queued_writes);
	fuse_flush_writepages(inode);
	spin_unlock(&fc->lock);

	for (i = 0; i < num_pages; i++)
		end_page_writeback(data->orig_pages[i]);
}