On May 23, 2011, at 3:55 AM, Andrey V. Elsukov wrote: > Hi, > > Since after r221788 many people report about lost of access to their > MBR partitions, i prepared new patch: > > http://people.freebsd.org/~ae/mbr_geometry.diff > > It removes from GEOM_PART_MBR constraints to alignment to track. > Now it is possible to create MBR partitions with exactly specified > start offset and size, and they will not be recalculated by kernel. > > Also the patch adds new option "-g" to the gpart(8) utility. This > option can be specified for "add" and "resize" subcommands. > gpart(8) uses information about provider's "geometry" and does > partition alignment how it did before for MBR. > > With these changes we give to users the choice how align their > partitions and also we still able to use some "broken" partition > tables.
This looks fairly good. I have one or two minor questions... Since we don't have a good review tool for the project, this may seem a little fragmented, but here goes: + if (pp->sectorsize > 4096) + return (EOPNOTSUPP); What's the motivation for this? This seems unrelated to the problem at hand. It may be good, but 4096-byte sector size is very new and I'm not sure MS-DOS can cope... :) There has been a long tradition in the MBR, however, of supporting different sector sizes to allow old-old-old school floppies that had 128 or 256 byte sectors to work, as well as allowing the supper-compressed 1.77MB floppies to work with their 1024-byte (or was that 2048-byte?) sectors. Not sure this really matters for reading, and for writing this case is so far beyond the edge I'm not even sure why I bring it up[*] In any event, I'd be tempted to use a #define for 4096 like MBR_MAX_SECTOR_SIZE. - msize = MIN(pp->mediasize / pp->sectorsize, UINT32_MAX); + msize = MIN(pp->mediasize / pp->sectorsize, 2 * UINT32_MAX); Why this change? I think that it is in two places. The rest looks good. Thanks for coming up with such a complete patch after my grumpy email... Warner [*] I guess old farts like to bring up this stuff to show how old they are :)_______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-geom To unsubscribe, send any mail to "[email protected]"
