On Wed, Jun 25, 2014 at 10:03:26PM +0200, Fabian Frederick wrote: > > > bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8); > > > > > Agreed - even though the FS data structures support 64-bit block > > count, I've never seen an OMFS fs with more than about 2M blocks > > (typical device had 20 gigs w/ 8k blocks). So it would make > > sense to bail in omfs_fill_super if that number is greater than > > 2^31 or so. > We could use unsigned int for bitmap instead of int or simply u64 ?
It doesn't really make sense to be a signed int, sure -- but even so making it a u64 without at least including a sanity check is probably not the way to go. OMFS allocates space for the entire free-space bitmap in memory, rather than loading its blocks on demand. That's admittedly pretty dumb, but I did it so that I could eventually support those FSes without a free-space bitmap (I've never been asked for that feature, though, and didn't have ReplayTV myself, so I don't believe that actually happened). If s_num_blocks won't fit in a u32, well then that's a pretty huge chunk of memory to allocate, and would represent a disk much bigger than the ones that were available when this FS was used on a few devices. (As for why the designers used u64 for all data structures, I guess just optimism?) -- Bob Copeland %% www.bobcopeland.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
