Alexander:
In the IA-64 port lives the EFI GUID Partition Table (GPT) partitioning
code. It's not yet merged into the mainline kernel tree. I've made a
first-stab at a patch to make the GPT code use the page cache, and I'd
appreciate you taking a look.
Start with 2.4.10
apply 2.4.11-pre1
apply your latest partition patch (partition-d-S11-pre1 I think)
apply latest ia64 patch
(there's one rejection in include/linux/genhd.h that's easy to fix)
apply http://domsch.com/linux/patches/linux-2.4.10-gpt-20011001.patch
apply
http://domsch.com/linux/patches/linux-2.4.10-gpt-pagecache-20011001.patch
The GPT code is in fs/partition/efi.[ch]. I'm concerned about reading a
page or partial page at the end of a disk, particularly an odd-sized disk.
In the pagecache patch I remove the set_blocksize() stuff, as it's not clear
if it's still needed, or if a disk with sectors % PAGE_CACHE_SIZE != 0 can
even read those last sectors.
Reading even the first few sectors fails with these patches, where if I
remove your partition patch and my pagecache patch, it works fine. I'm
certain it's a bug in my read_lba() code, which could use to be optimized
also.
static size_t
read_lba(struct gendisk *hd, struct block_device *bdev, u64 lba, u8 *buffer,
size_t count)
{
size_t totalreadcount = 0, bytesread;
int i, blockstoread, blocksize;
Sect sect;
unsigned char *data=NULL;
if (!hd || !buffer || !count) return 0;
blocksize = get_hardsect_size(to_kdev_t(bdev->bd_dev));
blockstoread = count / blocksize;
if (count % blocksize) blockstoread += 1;
for (i=0; i<blockstoread; i++) {
data = read_dev_sector(bdev, lba, §);
if (!data) {
put_dev_sector(sect);
return totalreadcount;
}
bytesread = (count > 512 ? 512 : count);
memcpy(buffer, data, bytesread);
put_dev_sector(sect);
buffer += bytesread; /* Advance the buffer pointer
*/
totalreadcount += bytesread; /* Advance the total read count
*/
count -= bytesread; /* Subtract bytesread from count
*/
}
return totalreadcount;
}
I'd appreciate your pointers.
Thanks,
Matt
-- Matt Domsch Sr. Software Engineer Dell Linux Solutions www.dell.com/linux #2 Linux Server provider with 17% in the US and 14% Worldwide (IDC)! #3 Unix provider with 18% in the US (Dataquest)! - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Oct 07 2001 - 21:00:24 EST