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Fix the data corruption on the swap-backed md.

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Assign the rv variable a success code if the pager was not asked for
the page.  Using an error code from the previous processed page caused
zeroing of the valid page, when e.g. the previous page was not
available in the pager.

Reported by:	lstewart
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
kib 2013-05-24 09:48:42 +00:00
parent 10ab667100
commit 6023beb9de
1 changed files with 7 additions and 1 deletions
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8
sys/dev/md/md.c
View File

@ -829,7 +829,9 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
m = vm_page_grab(sc->object, i, VM_ALLOC_NORMAL |
VM_ALLOC_RETRY);
if (bp->bio_cmd == BIO_READ) {
if (m->valid != VM_PAGE_BITS_ALL)
if (m->valid == VM_PAGE_BITS_ALL)
rv = VM_PAGER_OK;
else
rv = vm_pager_get_pages(sc->object, &m, 1, 0);
if (rv == VM_PAGER_ERROR) {
vm_page_wakeup(m);
@ -854,6 +856,8 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
} else if (bp->bio_cmd == BIO_WRITE) {
if (len != PAGE_SIZE && m->valid != VM_PAGE_BITS_ALL)
rv = vm_pager_get_pages(sc->object, &m, 1, 0);
else
rv = VM_PAGER_OK;
if (rv == VM_PAGER_ERROR) {
vm_page_wakeup(m);
break;
@ -868,6 +872,8 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
} else if (bp->bio_cmd == BIO_DELETE) {
if (len != PAGE_SIZE && m->valid != VM_PAGE_BITS_ALL)
rv = vm_pager_get_pages(sc->object, &m, 1, 0);
else
rv = VM_PAGER_OK;
if (rv == VM_PAGER_ERROR) {
vm_page_wakeup(m);
break;