[GIT PULL] bdev size cleanups

[GIT PULL] bdev size cleanups

[Jens Axboe]

Hi Linus,

On top of the core block branch, this topic branch cleans up the bdev
size handling.

Please pull!


The following changes since commit 4f5022453acd0f7b28012e20b7d048470f129894:

  nvme: wire up completion batching for the IRQ path (2021-10-18 14:40:47 -0600)

are available in the Git repository at:

  git://git.kernel.dk/linux-block.git tags/for-5.16/bdev-size-2021-10-29

for you to fetch changes up to 97eeb5fc14cc4b2091df8b841a07a1ac69f2d762:

  partitions/ibm: use bdev_nr_sectors instead of open coding it (2021-10-19 06:17:33 -0600)

----------------------------------------------------------------
for-5.16/bdev-size-2021-10-29

----------------------------------------------------------------
Christoph Hellwig (33):
      block: move the SECTOR_SIZE related definitions to blk_types.h
      block: add a bdev_nr_bytes helper
      bcache: remove bdev_sectors
      drbd: use bdev_nr_sectors instead of open coding it
      dm: use bdev_nr_sectors and bdev_nr_bytes instead of open coding them
      md: use bdev_nr_sectors instead of open coding it
      nvmet: use bdev_nr_bytes instead of open coding it
      target/iblock: use bdev_nr_bytes instead of open coding it
      fs: use bdev_nr_bytes instead of open coding it in blkdev_max_block
      fs: simplify init_page_buffers
      affs: use bdev_nr_sectors instead of open coding it
      btrfs: use bdev_nr_bytes instead of open coding it
      cramfs: use bdev_nr_bytes instead of open coding it
      fat: use bdev_nr_sectors instead of open coding it
      hfs: use bdev_nr_sectors instead of open coding it
      hfsplus: use bdev_nr_sectors instead of open coding it
      jfs: use bdev_nr_bytes instead of open coding it
      nfs/blocklayout: use bdev_nr_bytes instead of open coding it
      nilfs2: use bdev_nr_bytes instead of open coding it
      ntfs3: use bdev_nr_bytes instead of open coding it
      pstore/blk: use bdev_nr_bytes instead of open coding it
      reiserfs: use bdev_nr_bytes instead of open coding it
      squashfs: use bdev_nr_bytes instead of open coding it
      block: use bdev_nr_bytes instead of open coding it in blkdev_fallocate
      block: add a sb_bdev_nr_blocks helper
      ext4: use sb_bdev_nr_blocks
      jfs: use sb_bdev_nr_blocks
      ntfs: use sb_bdev_nr_blocks
      reiserfs: use sb_bdev_nr_blocks
      udf: use sb_bdev_nr_blocks
      block/ioctl: use bdev_nr_sectors and bdev_nr_bytes
      partitions/efi: use bdev_nr_bytes instead of open coding it
      partitions/ibm: use bdev_nr_sectors instead of open coding it

Jens Axboe (1):
      block: cache inode size in bdev

 block/fops.c                        |  2 +-
 block/genhd.c                       |  1 +
 block/ioctl.c                       | 20 ++++++++------------
 block/partitions/core.c             |  1 +
 block/partitions/efi.c              |  2 +-
 block/partitions/ibm.c              | 19 ++++++++++---------
 drivers/block/drbd/drbd_int.h       |  3 +--
 drivers/md/bcache/super.c           |  2 +-
 drivers/md/bcache/util.h            |  4 ----
 drivers/md/bcache/writeback.c       |  2 +-
 drivers/md/dm-bufio.c               |  2 +-
 drivers/md/dm-cache-metadata.c      |  2 +-
 drivers/md/dm-cache-target.c        |  2 +-
 drivers/md/dm-clone-target.c        |  2 +-
 drivers/md/dm-dust.c                |  5 ++---
 drivers/md/dm-ebs-target.c          |  2 +-
 drivers/md/dm-era-target.c          |  2 +-
 drivers/md/dm-exception-store.h     |  2 +-
 drivers/md/dm-flakey.c              |  3 +--
 drivers/md/dm-integrity.c           |  6 +++---
 drivers/md/dm-linear.c              |  3 +--
 drivers/md/dm-log-writes.c          |  4 ++--
 drivers/md/dm-log.c                 |  2 +-
 drivers/md/dm-mpath.c               |  2 +-
 drivers/md/dm-raid.c                |  6 +++---
 drivers/md/dm-switch.c              |  2 +-
 drivers/md/dm-table.c               |  3 +--
 drivers/md/dm-thin-metadata.c       |  2 +-
 drivers/md/dm-thin.c                |  2 +-
 drivers/md/dm-verity-target.c       |  3 +--
 drivers/md/dm-writecache.c          |  2 +-
 drivers/md/dm-zoned-target.c        |  2 +-
 drivers/md/md.c                     | 26 +++++++++++---------------
 drivers/nvme/target/io-cmd-bdev.c   |  4 ++--
 drivers/target/target_core_iblock.c |  4 ++--
 fs/affs/super.c                     |  2 +-
 fs/btrfs/dev-replace.c              |  3 +--
 fs/btrfs/disk-io.c                  |  2 +-
 fs/btrfs/ioctl.c                    |  4 ++--
 fs/btrfs/volumes.c                  |  8 ++++----
 fs/buffer.c                         |  4 ++--
 fs/cramfs/inode.c                   |  2 +-
 fs/ext4/super.c                     |  2 +-
 fs/fat/inode.c                      |  5 +----
 fs/hfs/mdb.c                        |  2 +-
 fs/hfsplus/wrapper.c                |  2 +-
 fs/jfs/resize.c                     |  5 ++---
 fs/jfs/super.c                      |  5 ++---
 fs/nfs/blocklayout/dev.c            |  4 ++--
 fs/nilfs2/ioctl.c                   |  2 +-
 fs/nilfs2/super.c                   |  2 +-
 fs/nilfs2/the_nilfs.c               |  2 +-
 fs/ntfs/super.c                     |  8 +++-----
 fs/ntfs3/super.c                    |  2 +-
 fs/pstore/blk.c                     |  8 +++-----
 fs/reiserfs/super.c                 |  8 ++------
 fs/squashfs/super.c                 |  5 +++--
 fs/udf/lowlevel.c                   |  5 ++---
 fs/udf/super.c                      |  9 +++------
 include/linux/blk_types.h           | 18 ++++++++++++++++++
 include/linux/blkdev.h              | 17 -----------------
 include/linux/genhd.h               | 13 ++++++++++++-
 62 files changed, 140 insertions(+), 160 deletions(-)

-- 
Jens Axboe

Re: [GIT PULL] bdev size cleanups

[Linus Torvalds]

On Sun, Oct 31, 2021 at 12:41 PM Jens Axboe <axboe@kernel.dk> wrote:
>
> On top of the core block branch, this topic branch cleans up the bdev
> size handling.

So on the whole this seems to be a good cleanup, but some of it worries me.

For example, it seems to have lost the cast to "loff_t" when
generating the byte size from a "sector_t".

Ok, so these days those are both 64-bit, and it doesn't actually
matter (the time when we had a 32-bit sector_t as an option are long
gone), but I think that bdev_nr_bytes() helper really ends up being
subtler than it looks. It very much depends on 'sector_t' and 'loff_t'
being the same size (although sector_t is an u64, loff_t ends up being
the signed version).

I've pulled this, but I do think it might have been better with the
type conversion being explicit. One of the reasons we had "sector_t"
originally was that it ended up being configuration-dependent, and
could be 32-bit. Those times may be gone, but it's still conceptually
a very different type from "loff_t".

                 Linus

Re: [GIT PULL] bdev size cleanups

[pr-tracker-bot]

The pull request you sent on Sun, 31 Oct 2021 13:41:51 -0600:

> git://git.kernel.dk/linux-block.git tags/for-5.16/bdev-size-2021-10-29

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/3f01727f750eae3e61b738b57355b2538ab179f4

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html

Re: [GIT PULL] bdev size cleanups

[Jens Axboe]

On 11/1/21 11:02 AM, Linus Torvalds wrote:
> On Sun, Oct 31, 2021 at 12:41 PM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> On top of the core block branch, this topic branch cleans up the bdev
>> size handling.
> 
> So on the whole this seems to be a good cleanup, but some of it worries me.
> 
> For example, it seems to have lost the cast to "loff_t" when
> generating the byte size from a "sector_t".
> 
> Ok, so these days those are both 64-bit, and it doesn't actually
> matter (the time when we had a 32-bit sector_t as an option are long
> gone), but I think that bdev_nr_bytes() helper really ends up being
> subtler than it looks. It very much depends on 'sector_t' and 'loff_t'
> being the same size (although sector_t is an u64, loff_t ends up being
> the signed version).
> 
> I've pulled this, but I do think it might have been better with the
> type conversion being explicit. One of the reasons we had "sector_t"
> originally was that it ended up being configuration-dependent, and
> could be 32-bit. Those times may be gone, but it's still conceptually
> a very different type from "loff_t".

Yes, probably safer just to make bdev_nr_bytes() return sector_t as
well, even if loff_t isn't strictly wrong. Christoph, want to do a
followup?

-- 
Jens Axboe

Re: [GIT PULL] bdev size cleanups

[Linus Torvalds]

On Mon, Nov 1, 2021 at 4:20 PM Jens Axboe <axboe@kernel.dk> wrote:
>
> Yes, probably safer just to make bdev_nr_bytes() return sector_t as
> well, even if loff_t isn't strictly wrong.

Well, that would actually change the sign of some of the existing
comparisons. Possibly changing their meaning entirely..

So having 'loff_t' being signed may be an odd choice for a byte size,
but it is what it is. At least the current set of cleanups seemed to
keep the type logic the same when it changed i_size_read() to be
bdev_nr_bytes() instead.

Changing it to 'sector_t' not only doesn't make conceptual sense when
it's a byte count, it might also be dangerous.

So my reaction was really that it wasn't obvious that bdev_nr_bytes()
did the shift in the right type.. It does happen to do that, but
historically sector_t was the smaller type.

            Linus

Re: [GIT PULL] bdev size cleanups

[Christoph Hellwig]

On Mon, Nov 01, 2021 at 05:19:58PM -0600, Jens Axboe wrote:
> Yes, probably safer just to make bdev_nr_bytes() return sector_t as
> well, even if loff_t isn't strictly wrong. Christoph, want to do a
> followup?

sector_t is wrong.  I actually did that in the very first version
accidentally and willy pointed out that this is wrong.  If Linus really
wants that we can add the cast.

Re: [GIT PULL] bdev size cleanups

[Jens Axboe]

On 11/1/21 5:50 PM, Linus Torvalds wrote:
> On Mon, Nov 1, 2021 at 4:20 PM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> Yes, probably safer just to make bdev_nr_bytes() return sector_t as
>> well, even if loff_t isn't strictly wrong.
> 
> Well, that would actually change the sign of some of the existing
> comparisons. Possibly changing their meaning entirely..
> 
> So having 'loff_t' being signed may be an odd choice for a byte size,
> but it is what it is. At least the current set of cleanups seemed to
> keep the type logic the same when it changed i_size_read() to be
> bdev_nr_bytes() instead.
> 
> Changing it to 'sector_t' not only doesn't make conceptual sense when
> it's a byte count, it might also be dangerous.
> 
> So my reaction was really that it wasn't obvious that bdev_nr_bytes()
> did the shift in the right type.. It does happen to do that, but
> historically sector_t was the smaller type.

OK, I misunderstood your original email, as per Christoph's email as
well. May be worth adding loff_t cast, if for nothing else just to have
it stick out to the next person touching it.

-- 
Jens Axboe