X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fsplice.c;h=05fd2787be989831e25c61dcce966360f534c544;hb=fedb595c66e1fbd5acafe0d43b7e95c13c936d61;hp=0b202425b0b5c6e92d0cb1a4fd5f92deab3df3c9;hpb=1432873af7ae29d4bb3c56114c05b539d078ca62;p=linux-2.6

diff --git a/fs/splice.c b/fs/splice.c
index 0b202425b0..05fd2787be 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -51,45 +51,57 @@ struct splice_pipe_desc {
  * addition of remove_mapping(). If success is returned, the caller may
  * attempt to reuse this page for another destination.
  */
-static int page_cache_pipe_buf_steal(struct pipe_inode_info *info,
+static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
 				     struct pipe_buffer *buf)
 {
 	struct page *page = buf->page;
-	struct address_space *mapping = page_mapping(page);
+	struct address_space *mapping;
 
 	lock_page(page);
 
-	WARN_ON(!PageUptodate(page));
+	mapping = page_mapping(page);
+	if (mapping) {
+		WARN_ON(!PageUptodate(page));
 
-	/*
-	 * At least for ext2 with nobh option, we need to wait on writeback
-	 * completing on this page, since we'll remove it from the pagecache.
-	 * Otherwise truncate wont wait on the page, allowing the disk
-	 * blocks to be reused by someone else before we actually wrote our
-	 * data to them. fs corruption ensues.
-	 */
-	wait_on_page_writeback(page);
+		/*
+		 * At least for ext2 with nobh option, we need to wait on
+		 * writeback completing on this page, since we'll remove it
+		 * from the pagecache.  Otherwise truncate wont wait on the
+		 * page, allowing the disk blocks to be reused by someone else
+		 * before we actually wrote our data to them. fs corruption
+		 * ensues.
+		 */
+		wait_on_page_writeback(page);
 
-	if (PagePrivate(page))
-		try_to_release_page(page, mapping_gfp_mask(mapping));
+		if (PagePrivate(page))
+			try_to_release_page(page, mapping_gfp_mask(mapping));
 
-	if (!remove_mapping(mapping, page)) {
-		unlock_page(page);
-		return 1;
+		/*
+		 * If we succeeded in removing the mapping, set LRU flag
+		 * and return good.
+		 */
+		if (remove_mapping(mapping, page)) {
+			buf->flags |= PIPE_BUF_FLAG_LRU;
+			return 0;
+		}
 	}
 
-	buf->flags |= PIPE_BUF_FLAG_LRU;
-	return 0;
+	/*
+	 * Raced with truncate or failed to remove page from current
+	 * address space, unlock and return failure.
+	 */
+	unlock_page(page);
+	return 1;
 }
 
-static void page_cache_pipe_buf_release(struct pipe_inode_info *info,
+static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
 					struct pipe_buffer *buf)
 {
 	page_cache_release(buf->page);
 	buf->flags &= ~PIPE_BUF_FLAG_LRU;
 }
 
-static int page_cache_pipe_buf_pin(struct pipe_inode_info *info,
+static int page_cache_pipe_buf_pin(struct pipe_inode_info *pipe,
 				   struct pipe_buffer *buf)
 {
 	struct page *page = buf->page;
@@ -324,6 +336,8 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 					      mapping_gfp_mask(mapping));
 			if (unlikely(error)) {
 				page_cache_release(page);
+				if (error == -EEXIST)
+					continue;
 				break;
 			}
 			/*
@@ -500,14 +514,14 @@ EXPORT_SYMBOL(generic_file_splice_read);
  * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
  * using sendpage(). Return the number of bytes sent.
  */
-static int pipe_to_sendpage(struct pipe_inode_info *info,
+static int pipe_to_sendpage(struct pipe_inode_info *pipe,
 			    struct pipe_buffer *buf, struct splice_desc *sd)
 {
 	struct file *file = sd->file;
 	loff_t pos = sd->pos;
 	int ret, more;
 
-	ret = buf->ops->pin(info, buf);
+	ret = buf->ops->pin(pipe, buf);
 	if (!ret) {
 		more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
 
@@ -538,7 +552,7 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
  * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create
  * a new page in the output file page cache and fill/dirty that.
  */
-static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
+static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 			struct splice_desc *sd)
 {
 	struct file *file = sd->file;
@@ -552,7 +566,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
 	/*
 	 * make sure the data in this buffer is uptodate
 	 */
-	ret = buf->ops->pin(info, buf);
+	ret = buf->ops->pin(pipe, buf);
 	if (unlikely(ret))
 		return ret;
 
@@ -573,7 +587,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
 		 * pagecache and we can reuse it. The page will also be
 		 * locked on successful return.
 		 */
-		if (buf->ops->steal(info, buf))
+		if (buf->ops->steal(pipe, buf))
 			goto find_page;
 
 		page = buf->page;
@@ -659,13 +673,13 @@ find_page:
 		/*
 		 * Careful, ->map() uses KM_USER0!
 		 */
-		char *src = buf->ops->map(info, buf, 1);
+		char *src = buf->ops->map(pipe, buf, 1);
 		char *dst = kmap_atomic(page, KM_USER1);
 
 		memcpy(dst + offset, src + buf->offset, this_len);
 		flush_dcache_page(page);
 		kunmap_atomic(dst, KM_USER1);
-		buf->ops->unmap(info, buf, src);
+		buf->ops->unmap(pipe, buf, src);
 	}
 
 	ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);