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We only need to check for overlaps if we increasing access counts.

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This commit is contained in:
phk 2004-07-04 13:44:48 +00:00
parent b2369d6e67
commit 099af98af5
1 changed files with 19 additions and 17 deletions
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36
sys/geom/geom_slice.c
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@ -99,23 +99,25 @@ g_slice_access(struct g_provider *pp, int dr, int dw, int de)
cp = LIST_FIRST(&gp->consumer);
KASSERT (cp != NULL, ("g_slice_access but no consumer"));
gsp = gp->softc;
gsl = &gsp->slices[pp->index];
for (u = 0; u < gsp->nslice; u++) {
gsl2 = &gsp->slices[u];
if (gsl2->length == 0)
continue;
if (u == pp->index)
continue;
if (gsl->offset + gsl->length <= gsl2->offset)
continue;
if (gsl2->offset + gsl2->length <= gsl->offset)
continue;
/* overlap */
pp2 = gsl2->provider;
if ((pp->acw + dw) > 0 && pp2->ace > 0)
return (EPERM);
if ((pp->ace + de) > 0 && pp2->acw > 0)
return (EPERM);
if (dr > 0 || dw > 0 || de > 0) {
gsl = &gsp->slices[pp->index];
for (u = 0; u < gsp->nslice; u++) {
gsl2 = &gsp->slices[u];
if (gsl2->length == 0)
continue;
if (u == pp->index)
continue;
if (gsl->offset + gsl->length <= gsl2->offset)
continue;
if (gsl2->offset + gsl2->length <= gsl->offset)
continue;
/* overlap */
pp2 = gsl2->provider;
if ((pp->acw + dw) > 0 && pp2->ace > 0)
return (EPERM);
if ((pp->ace + de) > 0 && pp2->acw > 0)
return (EPERM);
}
}
/* On first open, grab an extra "exclusive" bit */
if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)