[PATCH] cont_prepare_write question

[Eli Carter <eli.carter@inet.com>]

 From a very basic look at cont_prepare_write() in fs/buffer.c, it looks 
like it needs this patch to prevent an infinite loop when extending a 
file by several blocks.  (>8 for the 0.5k block case)

--- linux-2.5.68-rmk1/fs/buffer.c	2003/04/22 15:13:04	1.1.2.3
+++ linux-2.5.68-rmk1/fs/buffer.c	2003/07/21 19:38:40
@@ -2118,6 +2118,7 @@
  			goto out_unmap;
  		kaddr = kmap_atomic(new_page, KM_USER0);
  		memset(kaddr+zerofrom, 0, PAGE_CACHE_SIZE-zerofrom);
+		*bytes += PAGE_CACHE_SIZE-zerofrom;
  		flush_dcache_page(new_page);
  		kunmap_atomic(kaddr, KM_USER0);
  		__block_commit_write(inode, new_page,

I'm not going to pretend that I understand why, or what this exactly 
accomplishes... it just seems to improve things somewhat in my case.  If 
someone could give a basic explanation of what is going on in this loop, 
particularly in regards to how the loop is supposed to end, or a pointer 
to something to read that would make this function clearer than mud, I'd 
be very grateful.

Thanks,

Eli
--------------------. "If it ain't broke now,
Eli Carter           \                  it will be soon." -- crypto-gram
eli.carter(a)inet.com `-------------------------------------------------