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  1. 28 Jul, 2022 3 commits
    • Mike Christie's avatar
      dm: Start pr_reserve from the same starting path · 70151087
      Mike Christie authored 
      When an app does a pr_reserve it will go to whatever path we happen to
be using at the time. This can result in errors when the app does a
second pr_reserve call and expects success but gets a failure because
the reserve is not done on the holder's path. This commit has us
always start trying to do reserves from the first path in the first
group.

Windows failover clustering will produce the type of pattern above.
With this commit, we will now pass its validation test for this case.
Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      70151087
    • Mike Christie's avatar
      dm: Allow dm_call_pr to be used for path searches · 8dd87f3c
      Mike Christie authored 
      The specs state that if you send a reserve down a path that is already
the holder success must be returned and if it goes down a path that
is not the holder reservation conflict must be returned. Windows
failover clustering will send a second reservation and expects that a
device returns success. The problem for multipathing is that for an
All Registrants reservation, we can send the reserve down any path but
for all other reservation types there is one path that is the holder.

To handle this we could add PR state to dm but that can get nasty.
Look at target_core_pr.c for an example of the type of things we'd
have to track. It will also get more complicated because other
initiators can change the state so we will have to add in async
event/sense handling.

This commit, and the 3 commits that follow, tries to keep dm simple
and keep just doing passthrough. This commit modifies dm_call_pr to be
able to find the first usable path that can execute our pr_op then
return. When dm_pr_reserve is converted to dm_call_pr in the next
commit for the normal case we will use the same path for every
reserve.
Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      8dd87f3c
    • Mike Snitzer's avatar
      dm: return early from dm_pr_call() if DM device is suspended · e120a5f1
      Mike Snitzer authored 
      Otherwise PR ops may be issued while the broader DM device is being
reconfigured, etc.

Fixes: 9c72bad1 ("dm: call PR reserve/unreserve on each underlying device")
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      e120a5f1
  3. 15 Jul, 2022 1 commit
    • Luo Meng's avatar
      dm thin: fix use-after-free crash in dm_sm_register_threshold_callback · 3534e5a5
      Luo Meng authored 
      Fault inject on pool metadata device reports:
  BUG: KASAN: use-after-free in dm_pool_register_metadata_threshold+0x40/0x80
  Read of size 8 at addr ffff8881b9d50068 by task dmsetup/950

  CPU: 7 PID: 950 Comm: dmsetup Tainted: G        W         5.19.0-rc6 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x34/0x44
   print_address_description.constprop.0.cold+0xeb/0x3f4
   kasan_report.cold+0xe6/0x147
   dm_pool_register_metadata_threshold+0x40/0x80
   pool_ctr+0xa0a/0x1150
   dm_table_add_target+0x2c8/0x640
   table_load+0x1fd/0x430
   ctl_ioctl+0x2c4/0x5a0
   dm_ctl_ioctl+0xa/0x10
   __x64_sys_ioctl+0xb3/0xd0
   do_syscall_64+0x35/0x80
   entry_SYSCALL_64_after_hwframe+0x46/0xb0

This can be easily reproduced using:
  echo offline > /sys/block/sda/device/state
  dd if=/dev/zero of=/dev/mapper/thin bs=4k count=10
  dmsetup load pool --table "0 20971520 thin-pool /dev/sda /dev/sdb 128 0 0"

If a metadata commit fails, the transaction will be aborted and the
metadata space maps will be destroyed. If a DM table reload then
happens for this failed thin-pool, a use-after-free will occur in
dm_sm_register_threshold_callback (called from
dm_pool_register_metadata_threshold).

Fix this by in dm_pool_register_metadata_threshold() by returning the
-EINVAL error if the thin-pool is in fail mode. Also fail pool_ctr()
with a new error message: "Error registering metadata threshold".

Fixes: ac8c3f3d ("dm thin: generate event when metadata threshold passed")
Cc: stable@vger.kernel.org
Reported-by: default avatarHulk Robot <hulkci@huawei.com>
Signed-off-by: default avatarLuo Meng <luomeng12@huawei.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      3534e5a5
  5. 14 Jul, 2022 6 commits
  7. 07 Jul, 2022 11 commits
    • Bagas Sanjaya's avatar
      Documentation: dm writecache: Render status list as list · 11093e6f
      Bagas Sanjaya authored 
      The status list isn't rendered as list, but rather as normal paragraph,
because there is missing blank line between "Status:" line and the list.

Fix the issue by adding the blank line separator.

Fixes: 48debafe ("dm: add writecache target")
Signed-off-by: default avatarBagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      11093e6f
    • Mauro Carvalho Chehab's avatar
      Documentation: dm writecache: add blank line before optional parameters · 8b301af4
      Mauro Carvalho Chehab authored 
      Otherwise this warning occurs:
  Documentation/admin-guide/device-mapper/writecache.rst:23: WARNING: Unexpected indentation.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      8b301af4
    • Zhang Jiaming's avatar
      dm snapshot: fix typo in snapshot_map() comment · 962c6296
      Zhang Jiaming authored 
      Signed-off-by: default avatarZhang Jiaming <jiaming@nfschina.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      962c6296
    • Jiang Jian's avatar
      dm raid: remove redundant "the" in parse_raid_params() comment · ce92fc4b
      Jiang Jian authored 
      Signed-off-by: default avatarJiang Jian <jiangjian@cdjrlc.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      ce92fc4b
    • Steven Lung's avatar
      dm cache: fix typo in 2 comment blocks · 5c29e784
      Steven Lung authored 
      Replace neccessarily with necessarily.
Signed-off-by: default avatarSteven Lung <1030steven@gmail.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      5c29e784
    • JeongHyeon Lee's avatar
      dm verity: fix checkpatch close brace error · 20e6fc85
      JeongHyeon Lee authored 
      Resolves: ERROR: else should follow close brace '}'
Signed-off-by: default avatarJeongHyeon Lee <jhs2.lee@samsung.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      20e6fc85
    • Mike Snitzer's avatar
      dm table: rename dm_target variable in dm_table_add_target() · 899ab445
      Mike Snitzer authored 
      Rename from "tgt" to "ti" so that all of dm-table.c code uses the same
naming for dm_target variables.
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      899ab445
    • Mike Snitzer's avatar
      dm table: audit all dm_table_get_target() callers · 564b5c54
      Mike Snitzer authored 
      All callers of dm_table_get_target() are expected to do proper bounds
checking on the index they pass.

Move dm_table_get_target() to dm-core.h to make it extra clear that only
DM core code should be using it. Switch it to be inlined while at it.

Standardize all DM core callers to use the same for loop pattern and
make associated variables as local as possible. Rename some variables
(e.g. s/table/t/ and s/tgt/ti/) along the way.
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      564b5c54
    • Mike Snitzer's avatar
      dm table: remove dm_table_get_num_targets() wrapper · 2aec377a
      Mike Snitzer authored 
      More efficient and readable to just access table->num_targets directly.
Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      2aec377a
    • Ming Lei's avatar
      dm: add two stage requeue mechanism · 8b211aac
      Ming Lei authored 
      Commit 61b6e2e5 ("dm: fix BLK_STS_DM_REQUEUE handling when dm_io
represents split bio") reverted DM core's bio splitting back to using
bio_split()+bio_chain() because it was found that otherwise DM's
BLK_STS_DM_REQUEUE would trigger a live-lock waiting for bio
completion that would never occur.

Restore using bio_trim()+bio_inc_remaining(), like was done in commit
7dd76d1f ("dm: improve bio splitting and associated IO
accounting"), but this time with proper handling for the above
scenario that is covered in more detail in the commit header for
61b6e2e5.

Solve this issue by adding a two staged dm_io requeue mechanism that
uses the new dm_bio_rewind() via dm_io_rewind():

1) requeue the dm_io into the requeue_list added to struct
   mapped_device, and schedule it via new added requeue work. This
   workqueue just clones the dm_io->orig_bio (which DM saves and
   ensures its end sector isn't modified). dm_io_rewind() uses the
   sectors and sectors_offset members of the dm_io that are recorded
   relative to the end of orig_bio: dm_bio_rewind()+bio_trim() are
   then used to make that cloned bio reflect the subset of the
   original bio that is represented by the dm_io that is being
   requeued.

2) the 2nd stage requeue is same with original requeue, but
   io->orig_bio points to new cloned bio (which matches the requeued
   dm_io as described above).

This allows DM core to shift the need for bio cloning from bio-split
time (during IO submission) to the less likely BLK_STS_DM_REQUEUE
handling (after IO completes with that error).
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      8b211aac
    • Ming Lei's avatar
      dm: add dm_bio_rewind() API to DM core · 61cbe788
      Ming Lei authored 
      Commit 7759eb23 ("block: remove bio_rewind_iter()") removed
a similar API for the following reasons:
    ```
    It is pointed that bio_rewind_iter() is one very bad API[1]:

    1) bio size may not be restored after rewinding

    2) it causes some bogus change, such as 5151842b (block: reset
    bi_iter.bi_done after splitting bio)

    3) rewinding really makes things complicated wrt. bio splitting

    4) unnecessary updating of .bi_done in fast path

    [1] https://marc.info/?t=153549924200005&r=1&w=2

    So this patch takes Kent's suggestion to restore one bio into its original
    state via saving bio iterator(struct bvec_iter) in bio_integrity_prep(),
    given now bio_rewind_iter() is only used by bio integrity code.
    ```
However, saving off a copy of the 32 bytes bio->bi_iter in case rewind
needed isn't efficient because it bloats per-bio-data for what is an
unlikely case. That suggestion also ignores the need to restore
crypto and integrity info.

Add dm_bio_rewind() API for a specific use-case that is much more narrow
than the previous more generic rewind code that was reverted:

1) most bios have a fixed end sector since bio split is done from front
   of the bio, if driver just records how many sectors between current
   bio's start sector and the original bio's end sector, the original
   position can be restored. Keeping the original bio's end sector
   fixed is a _hard_ requirement for this interface!

2) if a bio's end sector won't change (usually bio_trim() isn't
   called, or in the case of DM it preserves original bio), user can
   restore the original position by storing sector offset from the
   current ->bi_iter.bi_sector to bio's end sector; together with
   saving bio size, only 8 bytes is needed to restore to original
   bio.

3) DM's requeue use case: when BLK_STS_DM_REQUEUE happens, DM core
   needs to restore to an "original bio" which represents the current
   dm_io to be requeued (which may be a subset of the original bio).
   By storing the sector offset from the original bio's end sector and
   dm_io's size, dm_bio_rewind() can restore such original bio. See
   commit 7dd76d1f ("dm: improve bio splitting and associated IO
   accounting") for more details on how DM does this. Leveraging this,
   allows DM core to shift the need for bio cloning from bio-split
   time (during IO submission) to the less likely BLK_STS_DM_REQUEUE
   handling (after IO completes with that error).

4) Unlike the original rewind API, dm_bio_rewind() doesn't add .bi_done
   to bvec_iter and there is no effect on the fast path.

Implement dm_bio_rewind() by factoring out clear helpers that it calls:
dm_bio_integrity_rewind, dm_bio_crypt_rewind and dm_bio_rewind_iter.

DM is able to ensure that dm_bio_rewind() is used safely but, given
the constraint that the bio's end must never change, other
hypothetical future callers may not take the same care. So make
dm_bio_rewind() and all supporting code local to DM to avoid risk of
hypothetical abuse. A "dm_" prefix was added to all functions to avoid
any namespace collisions.
Suggested-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
      61cbe788
  9. 29 Jun, 2022 6 commits
  11. 28 Jun, 2022 12 commits
  13. 27 Jun, 2022 1 commit
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