[PATCH] hfs: don't dirty unchanged inode

If inode size hasn't changed, don't do anything further in truncate, which
also prevents a dirty inode, what might upset some readonly devices quite
badly.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index cbc8510..5ea6b3d 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -482,7 +482,8 @@
 		page_cache_release(page);
 		mark_inode_dirty(inode);
 		return;
-	}
+	} else if (inode->i_size == HFS_I(inode)->phys_size)
+		return;
 	size = inode->i_size + HFS_SB(sb)->alloc_blksz - 1;
 	blk_cnt = size / HFS_SB(sb)->alloc_blksz;
 	alloc_cnt = HFS_I(inode)->alloc_blocks;