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When a DEV class consumer is orphan'ed we need to wait for all the

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outstanding requests to return before we unravel the mesh.

It is very important that the stuff below us plays nice and don't
overlook a couple of outstanding bio's, because until they remember
the geom event thread is blocked.  At an expense in code here this
could be made more robust, but I actually _want_ a robust failure
in this case so any offending drivers can be fixed.
This commit is contained in:
Poul-Henning Kamp 2003-03-09 09:28:45 +00:00
parent d03c79eea1
commit df6c9fe955
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=112024
1 changed files with 20 additions and 11 deletions
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31
sys/geom/geom_dev.c
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@ -398,12 +398,14 @@ g_dev_strategy(struct bio *bp)
/*
* g_dev_orphan()
*
* Called from below when the provider orphaned us. It is our responsibility
* to get the access counts back to zero, until we do so the stack below will
* not unravel. We must clear the kernel-dump settings, if this is the
* current dumpdev. We call destroy_dev(9) to send our dev_t the way of
* punched cards and if we have non-zero access counts, we call down with
* them negated before we detattch and selfdestruct.
* Called from below when the provider orphaned us.
* - Clear any dump settings.
* - Destroy the dev_t to prevent any more request from coming in. The
* provider is already marked with an error, so anything which comes in
* in the interrim will be returned immediately.
* - Wait for any outstanding I/O to finish.
* - Set our access counts to zero, whatever they were.
* - Detach and self-destruct.
*/
static void
@ -412,18 +414,25 @@ g_dev_orphan(struct g_consumer *cp)
struct g_geom *gp;
dev_t dev;
gp = cp->geom;
g_trace(G_T_TOPOLOGY, "g_dev_orphan(%p(%s))", cp, gp->name);
g_topology_assert();
if (cp->stat->nop != cp->stat->nend) /* XXX ? */
return;
gp = cp->geom;
dev = gp->softc;
g_trace(G_T_TOPOLOGY, "g_dev_orphan(%p(%s))", cp, gp->name);
/* Reset any dump-area set on this device */
if (dev->si_flags & SI_DUMPDEV)
set_dumper(NULL);
/* XXX: we may need Giant for now */
/* Destroy the dev_t so we get no more requests */
destroy_dev(dev);
/* Wait for the cows to come home */
while (cp->nstart != cp->nend)
msleep(&dev, NULL, PRIBIO, "gdevorphan", 1);
if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
g_access_rel(cp, -cp->acr, -cp->acw, -cp->ace);
g_detach(cp);
g_destroy_consumer(cp);
g_destroy_geom(gp);