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From: Leisner.Henr@xerox.com (Marty)
Newsgroups: comp.os.minix
Subject: RE:  Bug reading block special devices (problem solved?)
Message-ID: <569@louie.udel.EDU>
Date: Thu, 8-Oct-87 11:13:08 EDT
Article-I.D.: louie.569
Posted: Thu Oct  8 11:13:08 1987
Date-Received: Sun, 11-Oct-87 02:08:38 EDT
Sender: mmdf@udel.EDU
Lines: 33

In between lines 9834 and 9835 in the Minix book, some code was inserted
for the 1.1 release.

This appears to be why I'm having the problem with block special
devices.

I changed
  if (mode_word == I_BLOCK_SPECIAL && f_size == 0) f_size = MAX_P_LONG;
  
  to
  
  if(mode_word == I_BLOCK_SPECIAL) f_size = MAX_P_LONG;


I'm not sure where f_size would come from for a block special device,
but if its
not 0, read won't allow read's beyond the limit of f_size.  Why bother
checking f_size at all (which comes out of the inode's i_size field).

I assume for block special devices, all read requests should issue a
request to the device driver and let the driver tell the file system if
there is an error.

Its interesting that write had no problem.


marty
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