From 016b661e2f717168e600f3c85f29e1a49f88e004 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 25 Apr 2006 15:42:00 +0200 Subject: [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 --- fs/splice.c | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-) (limited to 'fs') diff --git a/fs/splice.c b/fs/splice.c index 4aa67254740..8c6030c762e 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -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; } -- cgit v1.2.3-18-g5258