Ensure that the sector size is a multiple of 4096 to avoid creating
unaligned partitions when the actual sector size is hidden from us. PR: 211361 MFC after: 3 days
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=304142
@ -795,6 +795,7 @@ gpart_max_free(struct ggeom *geom, intmax_t *npartstart)
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{
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struct gconfig *gc;
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struct gprovider *pp, **providers;
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intmax_t sectorsize, stripesize, offset;
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intmax_t lastend;
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intmax_t start, end;
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intmax_t maxsize, maxstart;
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@ -845,12 +846,25 @@ gpart_max_free(struct ggeom *geom, intmax_t *npartstart)
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pp = LIST_FIRST(&geom->lg_consumer)->lg_provider;
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/* Compute beginning of new partition and maximum available space */
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if (pp->lg_stripesize > 0 &&
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(maxstart*pp->lg_sectorsize % pp->lg_stripesize) != 0) {
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intmax_t offset = (pp->lg_stripesize -
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((maxstart*pp->lg_sectorsize) % pp->lg_stripesize)) /
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pp->lg_sectorsize;
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/*
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* Round the start and size of the largest available space up to
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* the nearest multiple of the adjusted stripe size.
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*
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* The adjusted stripe size is the least common multiple of the
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* actual stripe size, or the sector size if no stripe size was
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* reported, and 4096. The reason for this is that contemporary
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* disks often have 4096-byte physical sectors but report 512
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* bytes instead for compatibility with older / broken operating
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* systems and BIOSes. For the same reasons, virtualized storage
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* may also report a 512-byte stripe size, or none at all.
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*/
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sectorsize = pp->lg_sectorsize;
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if ((stripesize = pp->lg_stripesize) == 0)
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stripesize = sectorsize;
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while (stripesize % 4096 != 0)
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stripesize *= 2;
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if ((offset = maxstart * sectorsize % stripesize) != 0) {
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offset = (stripesize - offset) / sectorsize;
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maxstart += offset;
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maxsize -= offset;
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}
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