Merge branch 'splice-2.6.22' of git://git.kernel.dk/data/git/linux-2.…

…6-block

* 'splice-2.6.22' of git://git.kernel.dk/data/git/linux-2.6-block:
  splice: __generic_file_splice_read: fix read/truncate race
  splice: __generic_file_splice_read: fix i_size_read() length checks
  splice: move balance_dirty_pages_ratelimited() outside of splice actor
  pipe: move pipe_inode_info structure decleration up before it's used
  splice: remove do_splice_direct() symbol export
  splice: move inode size check into generic_file_splice_read()

fs/splice.c

@@ -272,7 +272,6 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 	struct page *page;
 	pgoff_t index, end_index;
 	loff_t isize;
-	size_t total_len;
 	int error, page_nr;
 	struct splice_pipe_desc spd = {
 		.pages = pages,
@@ -298,7 +297,6 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 	 * Now fill in the holes:
 	 */
 	error = 0;
-	total_len = 0;
 
 	/*
 	 * Lookup the (hopefully) full range of pages we need.
@@ -415,43 +413,47 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 
 				break;
 			}
+		}
+fill_it:
+		/*
+		 * i_size must be checked after PageUptodate.
+		 */
+		isize = i_size_read(mapping->host);
+		end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+		if (unlikely(!isize || index > end_index))
+			break;
+
+		/*
+		 * if this is the last page, see if we need to shrink
+		 * the length and stop
+		 */
+		if (end_index == index) {
+			unsigned int plen;
 
 			/*
-			 * i_size must be checked after ->readpage().
+			 * max good bytes in this page
 			 */
-			isize = i_size_read(mapping->host);
-			end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
-			if (unlikely(!isize || index > end_index))
+			plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
+			if (plen <= loff)
 				break;
 
 			/*
-			 * if this is the last page, see if we need to shrink
-			 * the length and stop
+			 * force quit after adding this page
 			 */
-			if (end_index == index) {
-				loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK);
-				if (total_len + loff > isize)
-					break;
-				/*
-				 * force quit after adding this page
-				 */
-				len = this_len;
-				this_len = min(this_len, loff);
-				loff = 0;
-			}
+			this_len = min(this_len, plen - loff);
+			len = this_len;
 		}
-fill_it:
+
 		partial[page_nr].offset = loff;
 		partial[page_nr].len = this_len;
 		len -= this_len;
-		total_len += this_len;
 		loff = 0;
 		spd.nr_pages++;
 		index++;
 	}
 
 	/*
-	 * Release any pages at the end, if we quit early. 'i' is how far
+	 * Release any pages at the end, if we quit early. 'page_nr' is how far
 	 * we got, 'nr_pages' is how many pages are in the map.
 	 */
 	while (page_nr < nr_pages)
@@ -478,10 +480,18 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
 {
 	ssize_t spliced;
 	int ret;
+	loff_t isize, left;
+
+	isize = i_size_read(in->f_mapping->host);
+	if (unlikely(*ppos >= isize))
+		return 0;
+
+	left = isize - *ppos;
+	if (unlikely(left < len))
+		len = left;
 
 	ret = 0;
 	spliced = 0;
-
 	while (len) {
 		ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
 
@@ -644,7 +654,6 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 	 * accessed, we are now done!
 	 */
 	mark_page_accessed(page);
-	balance_dirty_pages_ratelimited(mapping);
 out:
 	page_cache_release(page);
 	unlock_page(page);
@@ -815,6 +824,7 @@ generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out,
 			if (err)
 				ret = err;
 		}
+		balance_dirty_pages_ratelimited(mapping);
 	}
 
 	return ret;
@@ -868,6 +878,7 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 			if (err)
 				ret = err;
 		}
+		balance_dirty_pages_ratelimited(mapping);
 	}
 
 	return ret;
@@ -922,7 +933,6 @@ static long do_splice_to(struct file *in, loff_t *ppos,
 			 struct pipe_inode_info *pipe, size_t len,
 			 unsigned int flags)
 {
-	loff_t isize, left;
 	int ret;
 
 	if (unlikely(!in->f_op || !in->f_op->splice_read))
@@ -935,14 +945,6 @@ static long do_splice_to(struct file *in, loff_t *ppos,
 	if (unlikely(ret < 0))
 		return ret;
 
-	isize = i_size_read(in->f_mapping->host);
-	if (unlikely(*ppos >= isize))
-		return 0;
-
-	left = isize - *ppos;
-	if (unlikely(left < len))
-		len = left;
-
 	return in->f_op->splice_read(in, ppos, pipe, len, flags);
 }
 
@@ -1058,8 +1060,6 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
 	return ret;
 }
 
-EXPORT_SYMBOL(do_splice_direct);
-
 /*
  * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
  * location, so checking ->i_pipe is not enough to verify that this is a

include/linux/pipe_fs_i.h

@@ -16,6 +16,21 @@ struct pipe_buffer {
 	unsigned int flags;
 };
 
+struct pipe_inode_info {
+	wait_queue_head_t wait;
+	unsigned int nrbufs, curbuf;
+	struct page *tmp_page;
+	unsigned int readers;
+	unsigned int writers;
+	unsigned int waiting_writers;
+	unsigned int r_counter;
+	unsigned int w_counter;
+	struct fasync_struct *fasync_readers;
+	struct fasync_struct *fasync_writers;
+	struct inode *inode;
+	struct pipe_buffer bufs[PIPE_BUFFERS];
+};
+
 /*
  * Note on the nesting of these functions:
  *
@@ -38,21 +53,6 @@ struct pipe_buf_operations {
 	void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
 };
 
-struct pipe_inode_info {
-	wait_queue_head_t wait;
-	unsigned int nrbufs, curbuf;
-	struct page *tmp_page;
-	unsigned int readers;
-	unsigned int writers;
-	unsigned int waiting_writers;
-	unsigned int r_counter;
-	unsigned int w_counter;
-	struct fasync_struct *fasync_readers;
-	struct fasync_struct *fasync_writers;
-	struct inode *inode;
-	struct pipe_buffer bufs[PIPE_BUFFERS];
-};
-
 /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
    memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
 #define PIPE_SIZE		PAGE_SIZE