linux-toradex.git/drivers/md/bcache, branch v6.7-rc8

Merge tag 'block-6.7-2023-12-01' of git://git.kernel.dk/linux

2023-12-01T21:39:30+00:00

Pull block fixes from Jens Axboe:

 - NVMe pull request via Keith:
     - Invalid namespace identification error handling (Marizio Ewan,
       Keith)
     - Fabrics keep-alive tuning (Mark)

 - Fix for a bad error check regression in bcache (Markus)

 - Fix for a performance regression with O_DIRECT (Ming)

 - Fix for a flush related deadlock (Ming)

 - Make the read-only warn on per-partition (Yu)

* tag 'block-6.7-2023-12-01' of git://git.kernel.dk/linux:
  nvme-core: check for too small lba shift
  blk-mq: don't count completed flush data request as inflight in case of quiesce
  block: Document the role of the two attribute groups
  block: warn once for each partition in bio_check_ro()
  block: move .bd_inode into 1st cacheline of block_device
  nvme: check for valid nvme_identify_ns() before using it
  nvme-core: fix a memory leak in nvme_ns_info_from_identify()
  nvme: fine-tune sending of first keep-alive
  bcache: revert replacing IS_ERR_OR_NULL with IS_ERR

Merge tag 'bcachefs-2023-11-29' of https://evilpiepirate.org/git/bcachefs

2023-12-01T21:02:16+00:00

Pull more bcachefs bugfixes from Kent Overstreet:

 - bcache & bcachefs were broken with CFI enabled; patch for closures to
   fix type punning

 - mark erasure coding as extra-experimental; there are incompatible
   disk space accounting changes coming for erasure coding, and I'm
   still seeing checksum errors in some tests

 - several fixes for durability-related issues (durability is a device
   specific setting where we can tell bcachefs that data on a given
   device should be counted as replicated x times)

 - a fix for a rare livelock when a btree node merge then updates a
   parent node that is almost full

 - fix a race in the device removal path, where dropping a pointer in a
   btree node to a device would be clobbered by an in flight btree write
   updating the btree node key on completion

 - fix one SRCU lock hold time warning in the btree gc code - ther's
   still a bunch more of these to fix

 - fix a rare race where we'd start copygc before initializing the "are
   we rw" percpu refcount; copygc would think we were already ro and die
   immediately

* tag 'bcachefs-2023-11-29' of https://evilpiepirate.org/git/bcachefs: (23 commits)
  bcachefs: Extra kthread_should_stop() calls for copygc
  bcachefs: Convert gc_alloc_start() to for_each_btree_key2()
  bcachefs: Fix race between btree writes and metadata drop
  bcachefs: move journal seq assertion
  bcachefs: -EROFS doesn't count as move_extent_start_fail
  bcachefs: trace_move_extent_start_fail() now includes errcode
  bcachefs: Fix split_race livelock
  bcachefs: Fix bucket data type for stripe buckets
  bcachefs: Add missing validation for jset_entry_data_usage
  bcachefs: Fix zstd compress workspace size
  bcachefs: bpos is misaligned on big endian
  bcachefs: Fix ec + durability calculation
  bcachefs: Data update path won't accidentaly grow replicas
  bcachefs: deallocate_extra_replicas()
  bcachefs: Proper refcounting for journal_keys
  bcachefs: preserve device path as device name
  bcachefs: Fix an endianness conversion
  bcachefs: Start gc, copygc, rebalance threads after initing writes ref
  bcachefs: Don't stop copygc thread on device resize
  bcachefs: Make sure bch2_move_ratelimit() also waits for move_ops
  ...

bcache: revert replacing IS_ERR_OR_NULL with IS_ERR

2023-11-24T16:39:03+00:00

Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in
node allocations") replaced IS_ERR_OR_NULL by IS_ERR. This leads to a
NULL pointer dereference.

BUG: kernel NULL pointer dereference, address: 0000000000000080
Call Trace:
 ? __die_body.cold+0x1a/0x1f
 ? page_fault_oops+0xd2/0x2b0
 ? exc_page_fault+0x70/0x170
 ? asm_exc_page_fault+0x22/0x30
 ? btree_node_free+0xf/0x160 [bcache]
 ? up_write+0x32/0x60
 btree_gc_coalesce+0x2aa/0x890 [bcache]
 ? bch_extent_bad+0x70/0x170 [bcache]
 btree_gc_recurse+0x130/0x390 [bcache]
 ? btree_gc_mark_node+0x72/0x230 [bcache]
 bch_btree_gc+0x5da/0x600 [bcache]
 ? cpuusage_read+0x10/0x10
 ? bch_btree_gc+0x600/0x600 [bcache]
 bch_gc_thread+0x135/0x180 [bcache]

The relevant code starts with:

    new_nodes[0] = NULL;

    for (i = 0; i < nodes; i++) {
        if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key)))
            goto out_nocoalesce;
    // ...
out_nocoalesce:
    // ...
    for (i = 0; i < nodes; i++)
        if (!IS_ERR(new_nodes[i])) {  // IS_ERR_OR_NULL before
028ddcac477b
            btree_node_free(new_nodes[i]);  // new_nodes[0] is NULL
            rw_unlock(true, new_nodes[i]);
        }

This patch replaces IS_ERR() by IS_ERR_OR_NULL() to fix this.

Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations")
Link: https://lore.kernel.org/all/3DF4A87A-2AC1-4893-AE5F-E921478419A9@suse.de/
Cc: stable@vger.kernel.org
Cc: Zheng Wang 
Cc: Coly Li 
Signed-off-by: Markus Weippert 
Signed-off-by: Jens Axboe

closures: CLOSURE_CALLBACK() to fix type punning

2023-11-24T05:29:58+00:00

Control flow integrity is now checking that type signatures match on
indirect function calls. That breaks closures, which embed a work_struct
in a closure in such a way that a closure_fn may also be used as a
workqueue fn by the underlying closure code.

So we have to change closure fns to take a work_struct as their
argument - but that results in a loss of clarity, as closure fns have
different semantics from normal workqueue functions (they run owning a
ref on the closure, which must be released with continue_at() or
closure_return()).

Thus, this patc introduces CLOSURE_CALLBACK() and closure_type() macros
as suggested by Kees, to smooth things over a bit.

Suggested-by: Kees Cook 
Cc: Coly Li 
Signed-off-by: Kent Overstreet

bcache: avoid NULL checking to c->root in run_cache_set()

2023-11-20T16:17:51+00:00

In run_cache_set() after c->root returned from bch_btree_node_get(), it
is checked by IS_ERR_OR_NULL(). Indeed it is unncessary to check NULL
because bch_btree_node_get() will not return NULL pointer to caller.

This patch replaces IS_ERR_OR_NULL() by IS_ERR() for the above reason.

Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-11-colyli@suse.de
Signed-off-by: Jens Axboe

bcache: add code comments for bch_btree_node_get() and __bch_btree_node_alloc()

2023-11-20T16:17:51+00:00

This patch adds code comments to bch_btree_node_get() and
__bch_btree_node_alloc() that NULL pointer will not be returned and it
is unnecessary to check NULL pointer by the callers of these routines.

Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-10-colyli@suse.de
Signed-off-by: Jens Axboe

bcache: replace a mistaken IS_ERR() by IS_ERR_OR_NULL() in btree_gc_coalesce()

2023-11-20T16:17:51+00:00

Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in
node allocations") do the following change inside btree_gc_coalesce(),

31 @@ -1340,7 +1340,7 @@ static int btree_gc_coalesce(
32         memset(new_nodes, 0, sizeof(new_nodes));
33         closure_init_stack(&cl);
34
35 -       while (nodes < GC_MERGE_NODES && !IS_ERR_OR_NULL(r[nodes].b))
36 +       while (nodes < GC_MERGE_NODES && !IS_ERR(r[nodes].b))
37                 keys += r[nodes++].keys;
38
39         blocks = btree_default_blocks(b->c) * 2 / 3;

At line 35 the original r[nodes].b is not always allocatored from
__bch_btree_node_alloc(), and possibly initialized as NULL pointer by
caller of btree_gc_coalesce(). Therefore the change at line 36 is not
correct.

This patch replaces the mistaken IS_ERR() by IS_ERR_OR_NULL() to avoid
potential issue.

Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations")
Cc:   # 6.5+
Cc: Zheng Wang 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-9-colyli@suse.de
Signed-off-by: Jens Axboe

bcache: fixup multi-threaded bch_sectors_dirty_init() wake-up race

2023-11-20T16:17:51+00:00

We get a kernel crash about "unable to handle kernel paging request":

```dmesg
[368033.032005] BUG: unable to handle kernel paging request at ffffffffad9ae4b5
[368033.032007] PGD fc3a0d067 P4D fc3a0d067 PUD fc3a0e063 PMD 8000000fc38000e1
[368033.032012] Oops: 0003 [#1] SMP PTI
[368033.032015] CPU: 23 PID: 55090 Comm: bch_dirtcnt[0] Kdump: loaded Tainted: G           OE    --------- -  - 4.18.0-147.5.1.es8_24.x86_64 #1
[368033.032017] Hardware name: Tsinghua Tongfang THTF Chaoqiang Server/072T6D, BIOS 2.4.3 01/17/2017
[368033.032027] RIP: 0010:native_queued_spin_lock_slowpath+0x183/0x1d0
[368033.032029] Code: 8b 02 48 85 c0 74 f6 48 89 c1 eb d0 c1 e9 12 83 e0
03 83 e9 01 48 c1 e0 05 48 63 c9 48 05 c0 3d 02 00 48 03 04 cd 60 68 93
ad <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 02
[368033.032031] RSP: 0018:ffffbb48852abe00 EFLAGS: 00010082
[368033.032032] RAX: ffffffffad9ae4b5 RBX: 0000000000000246 RCX: 0000000000003bf3
[368033.032033] RDX: ffff97b0ff8e3dc0 RSI: 0000000000600000 RDI: ffffbb4884743c68
[368033.032034] RBP: 0000000000000001 R08: 0000000000000000 R09: 000007ffffffffff
[368033.032035] R10: ffffbb486bb01000 R11: 0000000000000001 R12: ffffffffc068da70
[368033.032036] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
[368033.032038] FS:  0000000000000000(0000) GS:ffff97b0ff8c0000(0000) knlGS:0000000000000000
[368033.032039] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[368033.032040] CR2: ffffffffad9ae4b5 CR3: 0000000fc3a0a002 CR4: 00000000003626e0
[368033.032042] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[368033.032043] bcache: bch_cached_dev_attach() Caching rbd479 as bcache462 on set 8cff3c36-4a76-4242-afaa-7630206bc70b
[368033.032045] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[368033.032046] Call Trace:
[368033.032054]  _raw_spin_lock_irqsave+0x32/0x40
[368033.032061]  __wake_up_common_lock+0x63/0xc0
[368033.032073]  ? bch_ptr_invalid+0x10/0x10 [bcache]
[368033.033502]  bch_dirty_init_thread+0x14c/0x160 [bcache]
[368033.033511]  ? read_dirty_submit+0x60/0x60 [bcache]
[368033.033516]  kthread+0x112/0x130
[368033.033520]  ? kthread_flush_work_fn+0x10/0x10
[368033.034505]  ret_from_fork+0x35/0x40
```

The crash occurred when call wake_up(&state->wait), and then we want
to look at the value in the state. However, bch_sectors_dirty_init()
is not found in the stack of any task. Since state is allocated on
the stack, we guess that bch_sectors_dirty_init() has exited, causing
bch_dirty_init_thread() to be unable to handle kernel paging request.

In order to verify this idea, we added some printing information during
wake_up(&state->wait). We find that "wake up" is printed twice, however
we only expect the last thread to wake up once.

```dmesg
[  994.641004] alcache: bch_dirty_init_thread() wake up
[  994.641018] alcache: bch_dirty_init_thread() wake up
[  994.641523] alcache: bch_sectors_dirty_init() init exit
```

There is a race. If bch_sectors_dirty_init() exits after the first wake
up, the second wake up will trigger this bug("unable to handle kernel
paging request").

Proceed as follows:

bch_sectors_dirty_init
    kthread_run ==============> bch_dirty_init_thread(bch_dirtcnt[0])
            ...                         ...
    atomic_inc(&state.started)          ...
            ...                         ...
    atomic_read(&state.enough)          ...
            ...                 atomic_set(&state->enough, 1)
    kthread_run ======================================================> bch_dirty_init_thread(bch_dirtcnt[1])
            ...                 atomic_dec_and_test(&state->started)            ...
    atomic_inc(&state.started)          ...                                     ...
            ...                 wake_up(&state->wait)                           ...
    atomic_read(&state.enough)                                          atomic_dec_and_test(&state->started)
            ...                                                                 ...
    wait_event(state.wait, atomic_read(&state.started) == 0)                    ...
    return                                                                      ...
                                                                        wake_up(&state->wait)

We believe it is very common to wake up twice if there is no dirty, but
crash is an extremely low probability event. It's hard for us to reproduce
this issue. We attached and detached continuously for a week, with a total
of more than one million attaches and only one crash.

Putting atomic_inc(&state.started) before kthread_run() can avoid waking
up twice.

Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Mingzhe Zou 
Cc:  
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-8-colyli@suse.de
Signed-off-by: Jens Axboe

bcache: fixup lock c->root error

2023-11-20T16:17:51+00:00

We had a problem with io hung because it was waiting for c->root to
release the lock.

crash> cache_set.root -l cache_set.list ffffa03fde4c0050
  root = 0xffff802ef454c800
crash> btree -o 0xffff802ef454c800 | grep rw_semaphore
  [ffff802ef454c858] struct rw_semaphore lock;
crash> struct rw_semaphore ffff802ef454c858
struct rw_semaphore {
  count = {
    counter = -4294967297
  },
  wait_list = {
    next = 0xffff00006786fc28,
    prev = 0xffff00005d0efac8
  },
  wait_lock = {
    raw_lock = {
      {
        val = {
          counter = 0
        },
        {
          locked = 0 '\000',
          pending = 0 '\000'
        },
        {
          locked_pending = 0,
          tail = 0
        }
      }
    }
  },
  osq = {
    tail = {
      counter = 0
    }
  },
  owner = 0xffffa03fdc586603
}

The "counter = -4294967297" means that lock count is -1 and a write lock
is being attempted. Then, we found that there is a btree with a counter
of 1 in btree_cache_freeable.

crash> cache_set -l cache_set.list ffffa03fde4c0050 -o|grep btree_cache
  [ffffa03fde4c1140] struct list_head btree_cache;
  [ffffa03fde4c1150] struct list_head btree_cache_freeable;
  [ffffa03fde4c1160] struct list_head btree_cache_freed;
  [ffffa03fde4c1170] unsigned int btree_cache_used;
  [ffffa03fde4c1178] wait_queue_head_t btree_cache_wait;
  [ffffa03fde4c1190] struct task_struct *btree_cache_alloc_lock;
crash> list -H ffffa03fde4c1140|wc -l
973
crash> list -H ffffa03fde4c1150|wc -l
1123
crash> cache_set.btree_cache_used -l cache_set.list ffffa03fde4c0050
  btree_cache_used = 2097
crash> list -s btree -l btree.list -H ffffa03fde4c1140|grep -E -A2 "^  lock = {" > btree_cache.txt
crash> list -s btree -l btree.list -H ffffa03fde4c1150|grep -E -A2 "^  lock = {" > btree_cache_freeable.txt
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# pwd
/var/crash/127.0.0.1-2023-08-04-16:40:28
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# cat btree_cache.txt|grep counter|grep -v "counter = 0"
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# cat btree_cache_freeable.txt|grep counter|grep -v "counter = 0"
      counter = 1

We found that this is a bug in bch_sectors_dirty_init() when locking c->root:
    (1). Thread X has locked c->root(A) write.
    (2). Thread Y failed to lock c->root(A), waiting for the lock(c->root A).
    (3). Thread X bch_btree_set_root() changes c->root from A to B.
    (4). Thread X releases the lock(c->root A).
    (5). Thread Y successfully locks c->root(A).
    (6). Thread Y releases the lock(c->root B).

        down_write locked ---(1)----------------------┐
                |                                     |
                |   down_read waiting ---(2)----┐     |
                |           |               ┌-------------┐ ┌-------------┐
        bch_btree_set_root ===(3)========>> | c->root   A | | c->root   B |
                |           |               └-------------┘ └-------------┘
            up_write ---(4)---------------------┘     |            |
                            |                         |            |
                    down_read locked ---(5)-----------┘            |
                            |                                      |
                        up_read ---(6)-----------------------------┘

Since c->root may change, the correct steps to lock c->root should be
the same as bch_root_usage(), compare after locking.

static unsigned int bch_root_usage(struct cache_set *c)
{
        unsigned int bytes = 0;
        struct bkey *k;
        struct btree *b;
        struct btree_iter iter;

        goto lock_root;

        do {
                rw_unlock(false, b);
lock_root:
                b = c->root;
                rw_lock(false, b, b->level);
        } while (b != c->root);

        for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
                bytes += bkey_bytes(k);

        rw_unlock(false, b);

        return (bytes * 100) / btree_bytes(c);
}

Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Mingzhe Zou 
Cc:  
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-7-colyli@suse.de
Signed-off-by: Jens Axboe

bcache: fixup init dirty data errors

2023-11-20T16:17:51+00:00

We found that after long run, the dirty_data of the bcache device
will have errors. This error cannot be eliminated unless re-register.

We also found that reattach after detach, this error can accumulate.

In bch_sectors_dirty_init(), all inode <= d->id keys will be recounted
again. This is wrong, we only need to count the keys of the current
device.

Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Mingzhe Zou 
Cc:  
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-6-colyli@suse.de
Signed-off-by: Jens Axboe