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Commit 016b661e authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
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[PATCH] splice: fix offset problems 



Make the move_from_pipe() actors return number of bytes processed, then
move_from_pipe() can decide more cleverly when to move on to the next
buffer.

This fixes problems with pipe offset and differing file offset.

Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent ba5f5d90

fs/splice.c

+27 −19
Original line number Diff line number Diff line
@@ -439,14 +439,13 @@ EXPORT_SYMBOL(generic_file_splice_read); 


/*

 * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'

 * using sendpage().

 * using sendpage(). Return the number of bytes sent.

 */

static int pipe_to_sendpage(struct pipe_inode_info *info,

			    struct pipe_buffer *buf, struct splice_desc *sd)

{

	struct file *file = sd->file;

	loff_t pos = sd->pos;

	unsigned int offset;

	ssize_t ret;

	void *ptr;

	int more;
@@ -461,16 +460,13 @@ static int pipe_to_sendpage(struct pipe_inode_info *info, 
	if (IS_ERR(ptr))

		return PTR_ERR(ptr);



	offset = pos & ~PAGE_CACHE_MASK;

	more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;



	ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more);

	ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len,

				   &pos, more);



	buf->ops->unmap(info, buf);

	if (ret == sd->len)

		return 0;



	return -EIO;

	return ret;

}



/*
@@ -499,7 +495,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 
	struct file *file = sd->file;

	struct address_space *mapping = file->f_mapping;

	gfp_t gfp_mask = mapping_gfp_mask(mapping);

	unsigned int offset;

	unsigned int offset, this_len;

	struct page *page;

	pgoff_t index;

	char *src;
@@ -515,6 +511,10 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 
	index = sd->pos >> PAGE_CACHE_SHIFT;

	offset = sd->pos & ~PAGE_CACHE_MASK;



	this_len = sd->len;

	if (this_len + offset > PAGE_CACHE_SIZE)

		this_len = PAGE_CACHE_SIZE - offset;



	/*

	 * Reuse buf page, if SPLICE_F_MOVE is set.

	 */
@@ -558,7 +558,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 
		 * the full page.

		 */

		if (!PageUptodate(page)) {

			if (sd->len < PAGE_CACHE_SIZE) {

			if (this_len < PAGE_CACHE_SIZE) {

				ret = mapping->a_ops->readpage(file, page);

				if (unlikely(ret))

					goto out;
@@ -582,7 +582,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 
		}

	}



	ret = mapping->a_ops->prepare_write(file, page, 0, sd->len);

	ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);

	if (ret == AOP_TRUNCATED_PAGE) {

		page_cache_release(page);

		goto find_page;
@@ -592,18 +592,22 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 
	if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {

		char *dst = kmap_atomic(page, KM_USER0);



		memcpy(dst + offset, src + buf->offset, sd->len);

		memcpy(dst + offset, src + buf->offset, this_len);

		flush_dcache_page(page);

		kunmap_atomic(dst, KM_USER0);

	}



	ret = mapping->a_ops->commit_write(file, page, 0, sd->len);

	ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);

	if (ret == AOP_TRUNCATED_PAGE) {

		page_cache_release(page);

		goto find_page;

	} else if (ret)

		goto out;



	/*

	 * Return the number of bytes written.

	 */

	ret = this_len;

	mark_page_accessed(page);

	balance_dirty_pages_ratelimited(mapping);

out:
@@ -652,16 +656,22 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out, 
				sd.len = sd.total_len;



			err = actor(pipe, buf, &sd);

			if (err) {

			if (err <= 0) {

				if (!ret && err != -ENODATA)

					ret = err;



				break;

			}



			ret += sd.len;

			buf->offset += sd.len;

			buf->len -= sd.len;

			ret += err;

			buf->offset += err;

			buf->len -= err;



			sd.len -= err;

			sd.pos += err;

			sd.total_len -= err;

			if (sd.len)

				continue;



			if (!buf->len) {

				buf->ops = NULL;
@@ -672,8 +682,6 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out, 
					do_wakeup = 1;

			}



			sd.pos += sd.len;

			sd.total_len -= sd.len;

			if (!sd.total_len)

				break;

		}