K 10
svn:author
V 6
dillon
K 8
svn:date
V 27
2002-03-06T19:53:08.000000Z
K 7
svn:log
V 821
MFC b_resid KASSERT from 1.85.  This is a safety check to make sure
that b_resid is the expected 0 value in preparation for a future commit
that will remove the b_resid calculation entirely.  It turns out that
b_resid WILL always be 0 except for the case where a write fails.  But
in the write failure case the buffer is still valid for reading and
we still want to treat it as such (as if b_resid were 0, even though it
isn't).  The filesystem code should not use b_resid in any calculations
except those involving short-read situations, and even then b_resid
will not be persistent for a VMIO backed buffer since the buffer may be
destroyed and later reconstituted, resetting b_resid to 0.  short-reads
are not used by most filesystems.  They are used by NFS only when reading
softlinks (using a non VMIO buffer). Joy.

END