From owner-freebsd-hackers  Fri Sep  7 12:55:16 2001
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Date: Fri, 7 Sep 2001 15:55:05 -0400 (EDT)
From: Zhihui Zhang <zzhang@cs.binghamton.edu>
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To: freebsd-hackers@freebsd.org
Subject: Error of BUF_STRATEGY()
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I use BUF_STRATEGY() in a kernel module to read a sector on a device like
/dev/ad0s3g. The biowait() routine after BUF_STRATEGY() gives me errors
like EALREADY and EPERM from time to time.  I find out that these errors
occur after I already wrote the same device by another program.  If I wait
a bit longer or try again, the BUF_STRATEGY() works fine and no error
happens.

I am wondering who is giving these errors. Is it the hardware? If so, the
kernel should somehow translate the hardware error to EALREADY and EPERM.
What is the exact meaning of these two errors?

Thanks,

-Zhihui


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