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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: Jens Axboe <axboe@suse.de>
This commit is contained in:
Jens Axboe 2006-04-25 15:42:00 +02:00 committed by Jens Axboe
parent ba5f5d90c4
commit 016b661e2f
1 changed files with 27 additions and 19 deletions
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46
fs/splice.c
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@ -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 @@ find_page:
* 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 @@ find_page:
}
}
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 @@ find_page:
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;
}