On Wed 18-05-11 14:12:06, Christoph Hellwig wrote:

quoted

 
 	if (unlikely(ret < 0))
 		unlock_page(page);
+	else {
+		/*
+		 * Freezing in progress? We check after the page is marked
+		 * dirty and with page lock held so if the test here fails, we
+		 * are sure freezing code will wait during syncing until the
+		 * page fault is done - at that point page will be dirty and
+		 * unlocked so freezing code will write it and writeprotect it
+		 * again.
+		 */
+		set_page_dirty(page);
+		if (inode->i_sb->s_frozen != SB_UNFROZEN) {
+			unlock_page(page);
+			ret = -EAGAIN;
+			goto out;
+		}
+	}
 out:
 	return ret;

The code structure looks a bit odd, why not:

	if (ret < 0)
		goto out_unlock;

	set_page_dirty(page);
	if (inode->i_sb->s_frozen != SB_UNFROZEN) {
		ret = -EAGAIN;
		goto out_unlock;
	}

	return 0;

out_unlock:
	unlock_page(page);
	return ret;
}

Otherwise looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

  Thanks, I've changed the flow as you suggested.

								Honza