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Ensure that the sector size is a multiple of 4096 to avoid creating

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unaligned partitions when the actual sector size is hidden from us.

PR:		211361
MFC after:	3 days
This commit is contained in:
Dag-Erling Smørgrav 2016-08-15 09:30:21 +00:00
parent 2bafd72fdb
commit 47ead00d5b
1 changed files with 20 additions and 6 deletions
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26
usr.sbin/bsdinstall/partedit/gpart_ops.c
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@ -795,6 +795,7 @@ gpart_max_free(struct ggeom *geom, intmax_t *npartstart)
{
struct gconfig *gc;
struct gprovider *pp, **providers;
intmax_t sectorsize, stripesize, offset;
intmax_t lastend;
intmax_t start, end;
intmax_t maxsize, maxstart;
@ -845,12 +846,25 @@ gpart_max_free(struct ggeom *geom, intmax_t *npartstart)
pp = LIST_FIRST(&geom->lg_consumer)->lg_provider;
/* Compute beginning of new partition and maximum available space */
if (pp->lg_stripesize > 0 &&
(maxstart*pp->lg_sectorsize % pp->lg_stripesize) != 0) {
intmax_t offset = (pp->lg_stripesize -
((maxstart*pp->lg_sectorsize) % pp->lg_stripesize)) /
pp->lg_sectorsize;
/*
* Round the start and size of the largest available space up to
* the nearest multiple of the adjusted stripe size.
*
* The adjusted stripe size is the least common multiple of the
* actual stripe size, or the sector size if no stripe size was
* reported, and 4096. The reason for this is that contemporary
* disks often have 4096-byte physical sectors but report 512
* bytes instead for compatibility with older / broken operating
* systems and BIOSes. For the same reasons, virtualized storage
* may also report a 512-byte stripe size, or none at all.
*/
sectorsize = pp->lg_sectorsize;
if ((stripesize = pp->lg_stripesize) == 0)
stripesize = sectorsize;
while (stripesize % 4096 != 0)
stripesize *= 2;
if ((offset = maxstart * sectorsize % stripesize) != 0) {
offset = (stripesize - offset) / sectorsize;
maxstart += offset;
maxsize -= offset;
}