Upstream-Status: Backport

unsquashfs: add a commment and fix some other comments

Signed-off-by: yanjun.zhu <yanjun.zhu@windriver.com> 

diff -urpN a/unsquashfs.c b/unsquashfs.c
--- a/unsquashfs.c	2012-11-30 15:27:14.000000000 +0800
+++ b/unsquashfs.c	2012-11-30 15:27:56.000000000 +0800
@@ -814,7 +814,7 @@ int write_file(struct inode *inode, char
 
 	/*
 	 * the writer thread is queued a squashfs_file structure describing the
- 	 * file.  If the file has one or more blocks or a fragments they are
+ 	 * file.  If the file has one or more blocks or a fragment they are
  	 * queued separately (references to blocks in the cache).
  	 */
 	file->fd = file_fd;
@@ -838,7 +838,7 @@ int write_file(struct inode *inode, char
 		block->offset = 0;
 		block->size = i == file_end ? inode->data & (block_size - 1) :
 			block_size;
-		if(block_list[i] == 0) /* sparse file */
+		if(block_list[i] == 0) /* sparse block */
 			block->buffer = NULL;
 		else {
 			block->buffer = cache_get(data_cache, start,
@@ -2161,6 +2161,10 @@ options:
 	block_size = sBlk.s.block_size;
 	block_log = sBlk.s.block_log;
 
+	/*
+	 * convert from queue size in Mbytes to queue size in
+	 * blocks
+	 */
 	fragment_buffer_size <<= 20 - block_log;
 	data_buffer_size <<= 20 - block_log;
 	initialise_threads(fragment_buffer_size, data_buffer_size);