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Fix arithmetical bug in vnode_pager_haspage(). The check against object size

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should be done not with the number of pages in the first block, but with the
overall number of pages.  While here, add KASSERT that makes sure that BMAP
doesn't return completely irrelevant blocks.

Reviewed by:	kib
Tested by:	pho
Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
This commit is contained in:
Gleb Smirnoff 2015-05-04 18:49:25 +00:00
parent 2b30fb2639
commit 84d313761d
1 changed files with 14 additions and 9 deletions
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23
sys/vm/vnode_pager.c
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@ -340,16 +340,21 @@ vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
*before += poff;
}
if (after) {
int numafter;
/*
* The BMAP vop can report a partial block in the
* 'after', but must not count blocks after EOF.
* Assert the latter, and truncate 'after' in case
* of the former.
*/
KASSERT(reqblock + *after <=
object->size * pagesperblock,
("%s: reqblock %jd after %d size %ju", __func__,
(intmax_t )reqblock, *after,
(uintmax_t )object->size));
*after *= pagesperblock;
numafter = pagesperblock - (poff + 1);
if (IDX_TO_OFF(pindex + numafter) >
object->un_pager.vnp.vnp_size) {
numafter =
OFF_TO_IDX(object->un_pager.vnp.vnp_size) -
pindex;
}
*after += numafter;
*after += pagesperblock - (poff + 1);
if (pindex + *after >= object->size)
*after = object->size - 1 - pindex;
}
} else {
if (before) {