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SubjectRe: [linux-lvm] *** ANNOUNCEMENT *** LVM 0.9.1 Beta 7 available at www.sistina.com
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Date
>>>>> "Heinz" == Heinz J Mauelshagen <Mauelshagen@sistina.com> writes:

Heinz> a tarball of the Linux Logical Volume Manager 0.9.1 Beta 7 is
Heinz> available now at

The following code is baaaad, m'kay...

[...]

down(&_pe_lock);
if((pe_lock_req.lock == LOCK_PE) &&
(rdev_map == pe_lock_req.data.pv_dev) &&
(rsector_map >= pe_lock_req.data.pv_offset) &&
(rsector_map < (pe_lock_req.data.pv_offset + vg_this->pe_size)) &&
((rw == WRITE) || (rw == WRITEA))) {
/* defer this bh until the PE has moved */
if(((int) bh) & 0x3) {
printk(KERN_ERR
"%s -- bh uses low 2 bits of pointer\n",
lvm_name);
up(&_pe_lock);
goto bad;
}

bh->b_reqnext = _pe_requests;
_pe_requests = (struct buffer_head *) ((int) bh | rw);
up(&_pe_lock);
up(&lv->lv_snapshot_sem);
return 0;
}
up(&_pe_lock);

[...]

/* handle all deferred io for this PE */
while(q) {
struct buffer_head *d_bh =
(struct buffer_head *) (q & ~0x3);
int rw = q & 0x3;
q = (uint) d_bh->b_reqnext;

/* resubmit this buffer head */
d_bh->b_reqnext = 0;
generic_make_request(rw, d_bh);
}


Not only is this an evil hack from hell, I don't understand why you go
through such a huge effort of storing rw in the pointer. Afaict, the
only valid value is WRITE. And WRITEA is #defined to WRITE in lvm.c.

--
Martin K. Petersen, Principal Linux Consultant, Linuxcare, Inc.
mkp@linuxcare.com, http://www.linuxcare.com/
SGI XFS for Linux Developer, http://oss.sgi.com/projects/xfs/
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