linux.git/block/bdev.c, branch v6.9-rc2

fs,block: get holder during claim

2024-03-18T09:32:44+00:00

Now that we open block devices as files we need to deal with the
realities that closing is a deferred operation. An operation on the
block device such as e.g., freeze, thaw, or removal that runs
concurrently with umount, tries to acquire a stable reference on the
holder. The holder might already be gone though. Make that reliable by
grabbing a passive reference to the holder during bdev_open() and
releasing it during bdev_release().

Fixes: f3a608827d1f ("bdev: open block device as files") # mainline only
Reported-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/ZfEQQ9jZZVes0WCZ@infradead.org
Reviewed-by: Jan Kara 
Reviewed-by: Christoph Hellwig 
Tested-by: Yi Zhang 
Reported-by: https://lore.kernel.org/r/CAHj4cs8tbDwKRwfS1=DmooP73ysM__xAb2PQc6XsAmWR+VuYmg@mail.gmail.com
Link: https://lore.kernel.org/r/20240315-freibad-annehmbar-ca68c375af91@brauner
Signed-off-by: Christian Brauner

Merge tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux

2024-03-11T18:43:44+00:00

Pull block updates from Jens Axboe:

 - MD pull requests via Song:
      - Cleanup redundant checks (Yu Kuai)
      - Remove deprecated headers (Marc Zyngier, Song Liu)
      - Concurrency fixes (Li Lingfeng)
      - Memory leak fix (Li Nan)
      - Refactor raid1 read_balance (Yu Kuai, Paul Luse)
      - Clean up and fix for md_ioctl (Li Nan)
      - Other small fixes (Gui-Dong Han, Heming Zhao)
      - MD atomic limits (Christoph)

 - NVMe pull request via Keith:
      - RDMA target enhancements (Max)
      - Fabrics fixes (Max, Guixin, Hannes)
      - Atomic queue_limits usage (Christoph)
      - Const use for class_register (Ricardo)
      - Identification error handling fixes (Shin'ichiro, Keith)

 - Improvement and cleanup for cached request handling (Christoph)

 - Moving towards atomic queue limits. Core changes and driver bits so
   far (Christoph)

 - Fix UAF issues in aoeblk (Chun-Yi)

 - Zoned fix and cleanups (Damien)

 - s390 dasd cleanups and fixes (Jan, Miroslav)

 - Block issue timestamp caching (me)

 - noio scope guarding for zoned IO (Johannes)

 - block/nvme PI improvements (Kanchan)

 - Ability to terminate long running discard loop (Keith)

 - bdev revalidation fix (Li)

 - Get rid of old nr_queues hack for kdump kernels (Ming)

 - Support for async deletion of ublk (Ming)

 - Improve IRQ bio recycling (Pavel)

 - Factor in CPU capacity for remote vs local completion (Qais)

 - Add shared_tags configfs entry for null_blk (Shin'ichiro

 - Fix for a regression in page refcounts introduced by the folio
   unification (Tony)

 - Misc fixes and cleanups (Arnd, Colin, John, Kunwu, Li, Navid,
   Ricardo, Roman, Tang, Uwe)

* tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux: (221 commits)
  block: partitions: only define function mac_fix_string for CONFIG_PPC_PMAC
  block/swim: Convert to platform remove callback returning void
  cdrom: gdrom: Convert to platform remove callback returning void
  block: remove disk_stack_limits
  md: remove mddev->queue
  md: don't initialize queue limits
  md/raid10: use the atomic queue limit update APIs
  md/raid5: use the atomic queue limit update APIs
  md/raid1: use the atomic queue limit update APIs
  md/raid0: use the atomic queue limit update APIs
  md: add queue limit helpers
  md: add a mddev_is_dm helper
  md: add a mddev_add_trace_msg helper
  md: add a mddev_trace_remap helper
  bcache: move calculation of stripe_size and io_opt into bcache_device_init
  virtio_blk: Do not use disk_set_max_open/active_zones()
  aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts
  block: move capacity validation to blkpg_do_ioctl()
  block: prevent division by zero in blk_rq_stat_sum()
  drbd: atomically update queue limits in drbd_reconsider_queue_parameters
  ...

block: remove bdev_handle completely

2024-02-25T11:05:28+00:00

We just need to use the holder to indicate whether a block device open
was exclusive or not. We did use to do that before but had to give that
up once we switched to struct bdev_handle. Before struct bdev_handle we
only stashed stuff in file->private_data if this was an exclusive open
but after struct bdev_handle we always set file->private_data to a
struct bdev_handle and so we had to use bdev_handle->mode or
bdev_handle->holder. Now that we don't use struct bdev_handle anymore we
can revert back to the old behavior.

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-32-adbd023e19cc@kernel.org
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner

block: don't rely on BLK_OPEN_RESTRICT_WRITES when yielding write access

2024-02-25T11:05:28+00:00

Make it possible to detected a block device that was opened with
restricted write access based only on BLK_OPEN_WRITE and
bdev->bd_writers < 0 so we won't have to claim another FMODE_* flag.

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-31-adbd023e19cc@kernel.org
Signed-off-by: Christian Brauner

bdev: remove bdev pointer from struct bdev_handle

2024-02-25T11:05:27+00:00

We can always go directly via:

* I_BDEV(bdev_file->f_inode)
* I_BDEV(bdev_file->f_mapping->host)

So keeping struct bdev in struct bdev_handle is redundant.

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-30-adbd023e19cc@kernel.org
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Christian Brauner

bdev: make struct bdev_handle private to the block layer

2024-02-25T11:05:27+00:00

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-29-adbd023e19cc@kernel.org
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner

bdev: make bdev_{release, open_by_dev}() private to block layer

2024-02-25T11:05:27+00:00

Move both of them to the private block header. There's no caller in the
tree anymore that uses them directly.

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-28-adbd023e19cc@kernel.org
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Christian Brauner

bdev: remove bdev_open_by_path()

2024-02-25T11:05:27+00:00

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-27-adbd023e19cc@kernel.org
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Christian Brauner

bdev: open block device as files

2024-02-25T11:05:21+00:00

Add two new helpers to allow opening block devices as files.
This is not the final infrastructure. This still opens the block device
before opening a struct a file. Until we have removed all references to
struct bdev_handle we can't switch the order:

* Introduce blk_to_file_flags() to translate from block specific to
  flags usable to pen a new file.
* Introduce bdev_file_open_by_{dev,path}().
* Introduce temporary sb_bdev_handle() helper to retrieve a struct
  bdev_handle from a block device file and update places that directly
  reference struct bdev_handle to rely on it.
* Don't count block device openes against the number of open files. A
  bdev_file_open_by_{dev,path}() file is never installed into any
  file descriptor table.

One idea that came to mind was to use kernel_tmpfile_open() which
would require us to pass a path and it would then call do_dentry_open()
going through the regular fops->open::blkdev_open() path. But then we're
back to the problem of routing block specific flags such as
BLK_OPEN_RESTRICT_WRITES through the open path and would have to waste
FMODE_* flags every time we add a new one. With this we can avoid using
a flag bit and we have more leeway in how we open block devices from
bdev_open_by_{dev,path}().

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-1-adbd023e19cc@kernel.org
Signed-off-by: Christian Brauner

bdev: remove SLAB_MEM_SPREAD flag usage

2024-02-24T20:16:08+00:00

The SLAB_MEM_SPREAD flag is already a no-op as of 6.8-rc1, remove
its usage so we can delete it from slab. No functional change.

Signed-off-by: Chengming Zhou 
Link: https://lore.kernel.org/r/20240224134646.829105-1-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe