Author: rpokala
Date: Wed Feb 8 08:37:43 2017
New Revision: 313433
URL: https://svnweb.freebsd.org/changeset/base/313433
Log:
MFC r304142: ensure stripe size is non-zero multiple of 4096
Ensure that the sector size is a multiple of 4096 to avoid creating
unaligned partitions when the actual sector size is hidden from us.
NOTE: This change was MFCed to stable/11 months ago as as r304448; I'm just
MFCing it back one more stream.
Modified:
stable/10/usr.sbin/bsdinstall/partedit/gpart_ops.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/usr.sbin/bsdinstall/partedit/gpart_ops.c
==============================================================================
--- stable/10/usr.sbin/bsdinstall/partedit/gpart_ops.c Wed Feb 8 08:35:05
2017 (r313432)
+++ stable/10/usr.sbin/bsdinstall/partedit/gpart_ops.c Wed Feb 8 08:37:43
2017 (r313433)
@@ -795,6 +795,7 @@ gpart_max_free(struct ggeom *geom, intma
{
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, intma
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;
}
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