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vfs: fix vfs_bio_clrbuf() for PAGE_SIZE > block size

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Calculate the desired page valid mask using math that will not
overflow the types used.

Sponsored by:	Netflix

Reviewed by:	mckusick, kib, markj
Differential Revision:	https://reviews.freebsd.org/D34837
This commit is contained in:
Chuck Silvers 2022-06-21 17:58:52 -07:00
parent 82817f26f8
commit 5bd21cbbd1
1 changed files with 5 additions and 2 deletions
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7
sys/kern/vfs_bio.c
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@ -4852,7 +4852,8 @@ vfs_bio_set_valid(struct buf *bp, int base, int size)
void
vfs_bio_clrbuf(struct buf *bp)
{
int i, j, mask, sa, ea, slide;
int i, j, sa, ea, slide, zbits;
vm_page_bits_t mask;
if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) {
clrbuf(bp);
@ -4871,7 +4872,9 @@ vfs_bio_clrbuf(struct buf *bp)
if (bp->b_pages[i] == bogus_page)
continue;
j = sa / DEV_BSIZE;
mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j;
zbits = (sizeof(vm_page_bits_t) * NBBY) -
(ea - sa) / DEV_BSIZE;
mask = (VM_PAGE_BITS_ALL >> zbits) << j;
if ((bp->b_pages[i]->valid & mask) == mask)
continue;
if ((bp->b_pages[i]->valid & mask) == 0)