linux-kernel - Q on ioctl BLKGETSIZE

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Date:	Tue, 18 Mar 2014 13:17:25 +0100
From:	"Ulrich Windl" <Ulrich.Windl@...uni-regensburg.de>
To:	<linux-kernel@...r.kernel.org>
Subject: Q on ioctl BLKGETSIZE

Hi!

I'm wondering (on a x86_64 SLES11 system):

"man 4 sd" says:
---
       BLKGETSIZE
              Returns the device size  in  sectors.   The  ioctl(2)  parameter
              should be a pointer to a long.
---

/usr/src/linux/block/ioctl.c (3.0.101-0.15) reads:
---
        case BLKGETSIZE:
                size = i_size_read(bdev->bd_inode);
                if ((size >> 9) > ~0UL)
                        return -EFBIG;
                return put_ulong(arg, size >> 9);
---

Three questions:
1) Shouldn't the manual page says that the sector size of always 512 Bytes, even on new disks with larger sectors?
2) Should the real sector size be used for new disks?
3) When using 512-bytes sector size, isn't the capacity limited to 2TB (2^31 kB)?

I'm not subscribed to LKML, so please keep me CC'd when answering.

Regards,
Ulrich

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