On Wed, Apr 26, 2000 at 11:26:37PM +0200, Marcus Brinkmann wrote:
> Anyway, here is a patch.
Well, I'm not (yet) a hurd hacker[1], but this patch strikes me as
fundamentally wrong (even if it fixes the problem for now).
The real problem is that io_seek uses a macro which is to be used only
when you want to _change_ an inode. You need another macro:
/* This macro locks the node associated with PROTID, and then
evaluates the expression OPERATION; then it unlocks everything, and
returns the value `err' (which can be set by OPERATION if
desired). */
#define ROACCESS_NODE_FIELD(PROTID, OPERATION) \
({ \
error_t err = 0; \
const struct node *np; \
\
if (!(PROTID)) \
return EOPNOTSUPP; \
\
np = (PROTID)->po->np; \
\
mutex_lock (&np->lock); \
(OPERATION); \
mutex_unlock (&np->lock); \
return err; \
})
and change the macro used in io_seek. And, of course, remove the
kludgy defines.
Also, the "const" helps at preventing you from shooting yourself in
the foot.
Some questions for the hurd hackers though:
- why should it be possible to pass NULL as the credential? Should
that be caught earlier, rather that duplicating the checking code in
all of the macro instances?
- why isn't the node locking the responsability of the caller?
- why isn't diskfs_notice_filechange call the responsability of the
caller?
OG.
[1] The state of the X support and the impossibility to handle
decently-sized partitions is what has made it difficult for me to
really start working on the code
