Commit Graph

262 Commits

Author SHA1 Message Date
Mikulas Patocka
8e0c9dacc3 dm thin: replace spin_lock_irqsave with spin_lock_irq
If we are in a place where it is known that interrupts are enabled,
functions spin_lock_irq/spin_unlock_irq should be used instead of
spin_lock_irqsave/spin_unlock_irqrestore.

spin_lock_irq and spin_unlock_irq are faster because they don't need to
push and pop the flags register.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-11-05 14:38:26 -05:00
Jason Cai (Xiang Feng)
70de2cbda8 dm thin: add sanity checks to thin-pool and external snapshot creation
Invoking dm_get_device() twice on the same device path with different
modes is dangerous.  Because in that case, upgrade_mode() will alloc a
new 'dm_dev' and free the old one, which may be referenced by a previous
caller.  Dereferencing the dangling pointer will trigger kernel NULL
pointer dereference.

The following two cases can reproduce this issue.  Actually, they are
invalid setups that must be disallowed, e.g.:

1. Creating a thin-pool with read_only mode, and the same device as
both metadata and data.

dmsetup create thinp --table \
    "0 41943040 thin-pool /dev/vdb /dev/vdb 128 0 1 read_only"

BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
...
Call Trace:
 new_read+0xfb/0x110 [dm_bufio]
 dm_bm_read_lock+0x43/0x190 [dm_persistent_data]
 ? kmem_cache_alloc_trace+0x15c/0x1e0
 __create_persistent_data_objects+0x65/0x3e0 [dm_thin_pool]
 dm_pool_metadata_open+0x8c/0xf0 [dm_thin_pool]
 pool_ctr.cold.79+0x213/0x913 [dm_thin_pool]
 ? realloc_argv+0x50/0x70 [dm_mod]
 dm_table_add_target+0x14e/0x330 [dm_mod]
 table_load+0x122/0x2e0 [dm_mod]
 ? dev_status+0x40/0x40 [dm_mod]
 ctl_ioctl+0x1aa/0x3e0 [dm_mod]
 dm_ctl_ioctl+0xa/0x10 [dm_mod]
 do_vfs_ioctl+0xa2/0x600
 ? handle_mm_fault+0xda/0x200
 ? __do_page_fault+0x26c/0x4f0
 ksys_ioctl+0x60/0x90
 __x64_sys_ioctl+0x16/0x20
 do_syscall_64+0x55/0x150
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

2. Creating a external snapshot using the same thin-pool device.

dmsetup create thinp --table \
    "0 41943040 thin-pool /dev/vdc /dev/vdb 128 0 2 ignore_discard"
dmsetup message /dev/mapper/thinp 0 "create_thin 0"
dmsetup create snap --table \
            "0 204800 thin /dev/mapper/thinp 0 /dev/mapper/thinp"

BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
...
Call Trace:
? __alloc_pages_nodemask+0x13c/0x2e0
retrieve_status+0xa5/0x1f0 [dm_mod]
? dm_get_live_or_inactive_table.isra.7+0x20/0x20 [dm_mod]
 table_status+0x61/0xa0 [dm_mod]
 ctl_ioctl+0x1aa/0x3e0 [dm_mod]
 dm_ctl_ioctl+0xa/0x10 [dm_mod]
 do_vfs_ioctl+0xa2/0x600
 ksys_ioctl+0x60/0x90
 ? ksys_write+0x4f/0xb0
 __x64_sys_ioctl+0x16/0x20
 do_syscall_64+0x55/0x150
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Jason Cai (Xiang Feng) <jason.cai@linux.alibaba.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-03-05 14:53:49 -05:00
Mike Snitzer
61697a6abd dm: eliminate 'split_discard_bios' flag from DM target interface
There is no need to have DM core split discards on behalf of a DM target
now that blk_queue_split() handles splitting discards based on the
queue_limits.  A DM target just needs to set max_discard_sectors,
discard_granularity, etc, in queue_limits.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-20 23:24:55 -05:00
Nikos Tsironis
4ae280b4ee dm thin: fix bug where bio that overwrites thin block ignores FUA
When provisioning a new data block for a virtual block, either because
the block was previously unallocated or because we are breaking sharing,
if the whole block of data is being overwritten the bio that triggered
the provisioning is issued immediately, skipping copying or zeroing of
the data block.

When this bio completes the new mapping is inserted in to the pool's
metadata by process_prepared_mapping(), where the bio completion is
signaled to the upper layers.

This completion is signaled without first committing the metadata.  If
the bio in question has the REQ_FUA flag set and the system crashes
right after its completion and before the next metadata commit, then the
write is lost despite the REQ_FUA flag requiring that I/O completion for
this request must only be signaled after the data has been committed to
non-volatile storage.

Fix this by deferring the completion of overwrite bios, with the REQ_FUA
flag set, until after the metadata has been committed.

Cc: stable@vger.kernel.org
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-14 19:02:29 -05:00
Joe Thornber
d445bd9cec dm thin: fix passdown_double_checking_shared_status()
Commit 00a0ea33b4 ("dm thin: do not queue freed thin mapping for next
stage processing") changed process_prepared_discard_passdown_pt1() to
increment all the blocks being discarded until after the passdown had
completed to avoid them being prematurely reused.

IO issued to a thin device that breaks sharing with a snapshot, followed
by a discard issued to snapshot(s) that previously shared the block(s),
results in passdown_double_checking_shared_status() being called to
iterate through the blocks double checking their reference count is zero
and issuing the passdown if so.  So a side effect of commit 00a0ea33b4
is passdown_double_checking_shared_status() was broken.

Fix this by checking if the block reference count is greater than 1.
Also, rename dm_pool_block_is_used() to dm_pool_block_is_shared().

Fixes: 00a0ea33b4 ("dm thin: do not queue freed thin mapping for next stage processing")
Cc: stable@vger.kernel.org # 4.9+
Reported-by: ryan.p.norwood@gmail.com
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-15 16:10:41 -05:00
Mike Snitzer
2af6c0703d dm thin: bump target version
Decoupled version bump from commit f6c367585d ("dm thin: send event
about thin-pool state change _after_ making it") because version bumps
just create conflicts when backporting to the stable trees.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-12 09:39:54 -05:00
Mike Snitzer
f6c367585d dm thin: send event about thin-pool state change _after_ making it
Sending a DM event before a thin-pool state change is about to happen is
a bug.  It wasn't realized until it became clear that userspace response
to the event raced with the actual state change that the event was
meant to notify about.

Fix this by first updating internal thin-pool state to reflect what the
DM event is being issued about.  This fixes a long-standing racey/buggy
userspace device-mapper-test-suite 'resize_io' test that would get an
event but not find the state it was looking for -- so it would just go
on to hang because no other events caused the test to reevaluate the
thin-pool's state.

Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-11 15:19:26 -05:00
John Pittman
22d4c291f5 dm thin: use refcount_t for thin_c reference counting
The API surrounding refcount_t should be used in place of atomic_t
when variables are being used as reference counters.  It can
potentially prevent reference counter overflows and use-after-free
conditions.  In the dm thin layer, one such example is tc->refcount.
Change this from the atomic_t API to the refcount_t API to prevent
mentioned conditions.

Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-10-16 14:27:03 -04:00
Joe Thornber
3ab9182816 dm thin metadata: try to avoid ever aborting transactions
Committing a transaction can consume some metadata of it's own, we now
reserve a small amount of metadata to cover this.  Free metadata
reported by the kernel will not include this reserve.

If any of the reserve has been used after a commit we enter a new
internal state PM_OUT_OF_METADATA_SPACE.  This is reported as
PM_READ_ONLY, so no userland changes are needed.  If the metadata
device is resized the pool will move back to PM_WRITE.

These changes mean we never need to abort and rollback a transaction due
to running out of metadata space.  This is particularly important
because there have been a handful of reports of data corruption against
DM thin-provisioning that can all be attributed to the thin-pool having
ran out of metadata space.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-09-10 17:03:18 -04:00
Hou Tao
75294442d8 dm thin: stop no_space_timeout worker when switching to write-mode
Now both check_for_space() and do_no_space_timeout() will read & write
pool->pf.error_if_no_space.  If these functions run concurrently, as
shown in the following case, the default setting of "queue_if_no_space"
can get lost.

precondition:
    * error_if_no_space = false (aka "queue_if_no_space")
    * pool is in Out-of-Data-Space (OODS) mode
    * no_space_timeout worker has been queued

CPU 0:                          CPU 1:
// delete a thin device
process_delete_mesg()
// check_for_space() invoked by commit()
set_pool_mode(pool, PM_WRITE)
    pool->pf.error_if_no_space = \
     pt->requested_pf.error_if_no_space

				// timeout, pool is still in OODS mode
				do_no_space_timeout
				    // "queue_if_no_space" config is lost
				    pool->pf.error_if_no_space = true
    pool->pf.mode = new_mode

Fix it by stopping no_space_timeout worker when switching to write mode.

Fixes: bcc696fac1 ("dm thin: stay in out-of-data-space mode once no_space_timeout expires")
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-08-07 14:30:29 -04:00
Mike Snitzer
7209049d40 dm kcopyd: return void from dm_kcopyd_copy()
dm_kcopyd_copy() only ever returns 0 so there is no need for callers to
account for possible failure.  Same goes for dm_kcopyd_zero().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-07-31 17:33:21 -04:00
Andy Grover
63c8ecb626 dm thin: include metadata_low_watermark threshold in pool status
The metadata low watermark threshold is set by the kernel.  But the
kernel depends on userspace to extend the thinpool metadata device when
the threshold is crossed.

Since the metadata low watermark threshold is not visible to userspace,
upon receiving an event, userspace cannot tell that the kernel wants the
metadata device extended, instead of some other eventing condition.
Making it visible (but not settable) enables userspace to affirmatively
know the kernel is asking for a metadata device extension, by comparing
metadata_low_watermark against nr_free_blocks_metadata, also reported in
status.

Current solutions like dmeventd have their own thresholds for extending
the data and metadata devices, and both devices are checked against
their thresholds on each event.  This lessens the value of the kernel-set
threshold, since userspace will either extend the metadata device sooner,
when receiving another event; or will receive the metadata lowater event
and do nothing, if dmeventd's threshold is less than the kernel's.
(This second case is dangerous. The metadata lowater event will not be
re-sent, so no further event will be generated before the metadata
device is out if space, unless some other event causes userspace to
recheck its thresholds.)

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-07-30 11:49:08 -04:00
Mike Snitzer
a685557fbb dm thin: handle running out of data space vs concurrent discard
Discards issued to a DM thin device can complete to userspace (via
fstrim) _before_ the metadata changes associated with the discards is
reflected in the thinp superblock (e.g. free blocks).  As such, if a
user constructs a test that loops repeatedly over these steps, block
allocation can fail due to discards not having completed yet:
1) fill thin device via filesystem file
2) remove file
3) fstrim

From initial report, here:
https://www.redhat.com/archives/dm-devel/2018-April/msg00022.html

"The root cause of this issue is that dm-thin will first remove
mapping and increase corresponding blocks' reference count to prevent
them from being reused before DISCARD bios get processed by the
underlying layers. However. increasing blocks' reference count could
also increase the nr_allocated_this_transaction in struct sm_disk
which makes smd->old_ll.nr_allocated +
smd->nr_allocated_this_transaction bigger than smd->old_ll.nr_blocks.
In this case, alloc_data_block() will never commit metadata to reset
the begin pointer of struct sm_disk, because sm_disk_get_nr_free()
always return an underflow value."

While there is room for improvement to the space-map accounting that
thinp is making use of: the reality is this test is inherently racey and
will result in the previous iteration's fstrim's discard(s) completing
vs concurrent block allocation, via dd, in the next iteration of the
loop.

No amount of space map accounting improvements will be able to allow
user's to use a block before a discard of that block has completed.

So the best we can really do is allow DM thinp to gracefully handle such
aggressive use of all the pool's data by degrading the pool into
out-of-data-space (OODS) mode.  We _should_ get that behaviour already
(if space map accounting didn't falsely cause alloc_data_block() to
believe free space was available).. but short of that we handle the
current reality that dm_pool_alloc_data_block() can return -ENOSPC.

Reported-by: Dennis Yang <dennisyang@qnap.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-06-27 08:49:46 -04:00
Linus Torvalds
b08fc5277a - Error path bug fix for overflow tests (Dan)
- Additional struct_size() conversions (Matthew, Kees)
 - Explicitly reported overflow fixes (Silvio, Kees)
 - Add missing kvcalloc() function (Kees)
 - Treewide conversions of allocators to use either 2-factor argument
   variant when available, or array_size() and array3_size() as needed (Kees)
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Merge tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull more overflow updates from Kees Cook:
 "The rest of the overflow changes for v4.18-rc1.

  This includes the explicit overflow fixes from Silvio, further
  struct_size() conversions from Matthew, and a bug fix from Dan.

  But the bulk of it is the treewide conversions to use either the
  2-factor argument allocators (e.g. kmalloc(a * b, ...) into
  kmalloc_array(a, b, ...) or the array_size() macros (e.g. vmalloc(a *
  b) into vmalloc(array_size(a, b)).

  Coccinelle was fighting me on several fronts, so I've done a bunch of
  manual whitespace updates in the patches as well.

  Summary:

   - Error path bug fix for overflow tests (Dan)

   - Additional struct_size() conversions (Matthew, Kees)

   - Explicitly reported overflow fixes (Silvio, Kees)

   - Add missing kvcalloc() function (Kees)

   - Treewide conversions of allocators to use either 2-factor argument
     variant when available, or array_size() and array3_size() as needed
     (Kees)"

* tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits)
  treewide: Use array_size in f2fs_kvzalloc()
  treewide: Use array_size() in f2fs_kzalloc()
  treewide: Use array_size() in f2fs_kmalloc()
  treewide: Use array_size() in sock_kmalloc()
  treewide: Use array_size() in kvzalloc_node()
  treewide: Use array_size() in vzalloc_node()
  treewide: Use array_size() in vzalloc()
  treewide: Use array_size() in vmalloc()
  treewide: devm_kzalloc() -> devm_kcalloc()
  treewide: devm_kmalloc() -> devm_kmalloc_array()
  treewide: kvzalloc() -> kvcalloc()
  treewide: kvmalloc() -> kvmalloc_array()
  treewide: kzalloc_node() -> kcalloc_node()
  treewide: kzalloc() -> kcalloc()
  treewide: kmalloc() -> kmalloc_array()
  mm: Introduce kvcalloc()
  video: uvesafb: Fix integer overflow in allocation
  UBIFS: Fix potential integer overflow in allocation
  leds: Use struct_size() in allocation
  Convert intel uncore to struct_size
  ...
2018-06-12 18:28:00 -07:00
Kees Cook
42bc47b353 treewide: Use array_size() in vmalloc()
The vmalloc() function has no 2-factor argument form, so multiplication
factors need to be wrapped in array_size(). This patch replaces cases of:

        vmalloc(a * b)

with:
        vmalloc(array_size(a, b))

as well as handling cases of:

        vmalloc(a * b * c)

with:

        vmalloc(array3_size(a, b, c))

This does, however, attempt to ignore constant size factors like:

        vmalloc(4 * 1024)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  vmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  vmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  vmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  vmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  vmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  vmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  vmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  vmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  vmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  vmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
  vmalloc(
-	sizeof(TYPE) * (COUNT_ID)
+	array_size(COUNT_ID, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(TYPE) * COUNT_ID
+	array_size(COUNT_ID, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(TYPE) * (COUNT_CONST)
+	array_size(COUNT_CONST, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(TYPE) * COUNT_CONST
+	array_size(COUNT_CONST, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(THING) * (COUNT_ID)
+	array_size(COUNT_ID, sizeof(THING))
  , ...)
|
  vmalloc(
-	sizeof(THING) * COUNT_ID
+	array_size(COUNT_ID, sizeof(THING))
  , ...)
|
  vmalloc(
-	sizeof(THING) * (COUNT_CONST)
+	array_size(COUNT_CONST, sizeof(THING))
  , ...)
|
  vmalloc(
-	sizeof(THING) * COUNT_CONST
+	array_size(COUNT_CONST, sizeof(THING))
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

  vmalloc(
-	SIZE * COUNT
+	array_size(COUNT, SIZE)
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  vmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  vmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  vmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  vmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  vmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  vmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  vmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  vmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  vmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  vmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  vmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  vmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  vmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  vmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  vmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  vmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  vmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  vmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  vmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  vmalloc(C1 * C2 * C3, ...)
|
  vmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants.
@@
expression E1, E2;
constant C1, C2;
@@

(
  vmalloc(C1 * C2, ...)
|
  vmalloc(
-	E1 * E2
+	array_size(E1, E2)
  , ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-12 16:19:22 -07:00
Mike Snitzer
72d711c876 dm: adjust structure members to improve alignment
Eliminate most holes in DM data structures that were modified by
commit 6f1c819c21 ("dm: convert to bioset_init()/mempool_init()").
Also prevent structure members from unnecessarily spanning cache
lines.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-06-08 11:53:14 -04:00
Kent Overstreet
d377535405 dm: Use kzalloc for all structs with embedded biosets/mempools
mempool_init()/bioset_init() require that the mempools/biosets be zeroed
first; they probably should not _require_ this, but not allocating those
structs with kzalloc is a fairly nonsensical thing to do (calling
mempool_exit()/bioset_exit() on an uninitialized mempool/bioset is legal
and safe, but only works if said memory was zeroed.)

Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-05 08:47:43 -06:00
Kent Overstreet
6f1c819c21 dm: convert to bioset_init()/mempool_init()
Convert dm to embedded bio sets.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30 15:33:32 -06:00
Mike Snitzer
1eb5fa849f dm: allow targets to return output from messages they are sent
Could be useful for a target to return stats or other information.
If a target does DMEMIT() anything to @result from its .message method
then it must return 1 to the caller.

Signed-off-By: Mike Snitzer <snitzer@redhat.com>
2018-04-03 15:04:10 -04:00
Luis de Bethencourt
bd6d1e0a5f dm thin: fix trailing semicolon in __remap_and_issue_shared_cell
The trailing semicolon is an empty statement that does no operation.
Removing it since it doesn't do anything.

Signed-off-by: Luis de Bethencourt <luisbg@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-29 13:44:57 -05:00
Mike Snitzer
d5ffebdd79 dm: backfill missing calls to mutex_destroy()
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-17 09:16:15 -05:00
monty_pavel@sina.com
7e6358d244 dm: fix various targets to dm_register_target after module __init resources created
A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>"
processes race to load the dm-thin-pool module:

 PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange"
  #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9
  0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992
  0000002 [ffff883cd743d730] oops_end at ffffffff81515c90
  0000003 [ffff883cd743d760] no_context at ffffffff81049f1b
  0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5
  0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce
  0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f
  0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae
  0000008 [ffff883cd743d980] page_fault at ffffffff81514f95
     [exception RIP: kmem_cache_alloc+108]
     RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046
     RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0
     RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000
     RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000
     R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0
     R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246
     ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
  0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5
 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083
 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4
 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool]
 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod]
 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod]
 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod]

The race results in a NULL pointer because:

Process A (vgchange -ay -K):
 	a. send DM_LIST_VERSIONS_CMD ioctl;
 	b. pool_target not registered;
 	c. modprobe dm_thin_pool and wait until end.

Process B (vgchange -ay -K):
 	a. send DM_LIST_VERSIONS_CMD ioctl;
 	b. pool_target registered;
 	c. table_load->dm_table_add_target->pool_ctr;
 	d. _new_mapping_cache is NULL and panic.
Note:
 	1. process A and process B are two concurrent processes.
 	2. pool_target can be detected by process B but
 	_new_mapping_cache initialization has not ended.

To fix dm-thin-pool, and other targets (cache, multipath, and snapshot)
with the same problem, simply dm_register_target() after all resources
created during module init (as labelled with __init) are finished.

Cc: stable@vger.kernel.org
Signed-off-by: monty <monty_pavel@sina.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-12-04 10:23:10 -05:00
Mark Rutland
6aa7de0591 locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 11:01:08 +02:00
Linus Torvalds
dff4d1f6fe - Some request-based DM core and DM multipath fixes and cleanups
- Constify a few variables in DM core and DM integrity
 
 - Add bufio optimization and checksum failure accounting to DM integrity
 
 - Fix DM integrity to avoid checking integrity of failed reads
 
 - Fix DM integrity to use init_completion
 
 - A couple DM log-writes target fixes
 
 - Simplify DAX flushing by eliminating the unnecessary flush abstraction
   that was stood up for DM's use.
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Merge tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Some request-based DM core and DM multipath fixes and cleanups

 - Constify a few variables in DM core and DM integrity

 - Add bufio optimization and checksum failure accounting to DM
   integrity

 - Fix DM integrity to avoid checking integrity of failed reads

 - Fix DM integrity to use init_completion

 - A couple DM log-writes target fixes

 - Simplify DAX flushing by eliminating the unnecessary flush
   abstraction that was stood up for DM's use.

* tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dax: remove the pmem_dax_ops->flush abstraction
  dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK
  dm integrity: make blk_integrity_profile structure const
  dm integrity: do not check integrity for failed read operations
  dm log writes: fix >512b sectorsize support
  dm log writes: don't use all the cpu while waiting to log blocks
  dm ioctl: constify ioctl lookup table
  dm: constify argument arrays
  dm integrity: count and display checksum failures
  dm integrity: optimize writing dm-bufio buffers that are partially changed
  dm rq: do not update rq partially in each ending bio
  dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior
  dm mpath: complain about unsupported __multipath_map_bio() return values
  dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through
2017-09-14 13:43:16 -07:00
Eric Biggers
5916a22b83 dm: constify argument arrays
The arrays of 'struct dm_arg' are never modified by the device-mapper
core, so constify them so that they are placed in .rodata.

(Exception: the args array in dm-raid cannot be constified because it is
allocated on the stack and modified.)

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-08-28 11:47:18 -04:00
Christoph Hellwig
74d46992e0 block: replace bi_bdev with a gendisk pointer and partitions index
This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23 12:49:55 -06:00
Linus Torvalds
c6b1e36c8f Merge branch 'for-4.13/block' of git://git.kernel.dk/linux-block
Pull core block/IO updates from Jens Axboe:
 "This is the main pull request for the block layer for 4.13. Not a huge
  round in terms of features, but there's a lot of churn related to some
  core cleanups.

  Note this depends on the UUID tree pull request, that Christoph
  already sent out.

  This pull request contains:

   - A series from Christoph, unifying the error/stats codes in the
     block layer. We now use blk_status_t everywhere, instead of using
     different schemes for different places.

   - Also from Christoph, some cleanups around request allocation and IO
     scheduler interactions in blk-mq.

   - And yet another series from Christoph, cleaning up how we handle
     and do bounce buffering in the block layer.

   - A blk-mq debugfs series from Bart, further improving on the support
     we have for exporting internal information to aid debugging IO
     hangs or stalls.

   - Also from Bart, a series that cleans up the request initialization
     differences across types of devices.

   - A series from Goldwyn Rodrigues, allowing the block layer to return
     failure if we will block and the user asked for non-blocking.

   - Patch from Hannes for supporting setting loop devices block size to
     that of the underlying device.

   - Two series of patches from Javier, fixing various issues with
     lightnvm, particular around pblk.

   - A series from me, adding support for write hints. This comes with
     NVMe support as well, so applications can help guide data placement
     on flash to improve performance, latencies, and write
     amplification.

   - A series from Ming, improving and hardening blk-mq support for
     stopping/starting and quiescing hardware queues.

   - Two pull requests for NVMe updates. Nothing major on the feature
     side, but lots of cleanups and bug fixes. From the usual crew.

   - A series from Neil Brown, greatly improving the bio rescue set
     support. Most notably, this kills the bio rescue work queues, if we
     don't really need them.

   - Lots of other little bug fixes that are all over the place"

* 'for-4.13/block' of git://git.kernel.dk/linux-block: (217 commits)
  lightnvm: pblk: set line bitmap check under debug
  lightnvm: pblk: verify that cache read is still valid
  lightnvm: pblk: add initialization check
  lightnvm: pblk: remove target using async. I/Os
  lightnvm: pblk: use vmalloc for GC data buffer
  lightnvm: pblk: use right metadata buffer for recovery
  lightnvm: pblk: schedule if data is not ready
  lightnvm: pblk: remove unused return variable
  lightnvm: pblk: fix double-free on pblk init
  lightnvm: pblk: fix bad le64 assignations
  nvme: Makefile: remove dead build rule
  blk-mq: map all HWQ also in hyperthreaded system
  nvmet-rdma: register ib_client to not deadlock in device removal
  nvme_fc: fix error recovery on link down.
  nvmet_fc: fix crashes on bad opcodes
  nvme_fc: Fix crash when nvme controller connection fails.
  nvme_fc: replace ioabort msleep loop with completion
  nvme_fc: fix double calls to nvme_cleanup_cmd()
  nvme-fabrics: verify that a controller returns the correct NQN
  nvme: simplify nvme_dev_attrs_are_visible
  ...
2017-07-03 10:34:51 -07:00
Vallish Vaidyeshwara
00a0ea33b4 dm thin: do not queue freed thin mapping for next stage processing
process_prepared_discard_passdown_pt1() should cleanup
dm_thin_new_mapping in cases of error.

dm_pool_inc_data_range() can fail trying to get a block reference:

metadata operation 'dm_pool_inc_data_range' failed: error = -61

When dm_pool_inc_data_range() fails, dm thin aborts current metadata
transaction and marks pool as PM_READ_ONLY. Memory for thin mapping
is released as well. However, current thin mapping will be queued
onto next stage as part of queue_passdown_pt2() or passdown_endio().
This dangling thin mapping memory when processed and accessed in
next stage will lead to device mapper crashing.

Code flow without fix:
-> process_prepared_discard_passdown_pt1(m)
   -> dm_thin_remove_range()
   -> discard passdown
      --> passdown_endio(m) queues m onto next stage
   -> dm_pool_inc_data_range() fails, frees memory m
            but does not remove it from next stage queue

-> process_prepared_discard_passdown_pt2(m)
   -> processes freed memory m and crashes

One such stack:

Call Trace:
[<ffffffffa037a46f>] dm_cell_release_no_holder+0x2f/0x70 [dm_bio_prison]
[<ffffffffa039b6dc>] cell_defer_no_holder+0x3c/0x80 [dm_thin_pool]
[<ffffffffa039b88b>] process_prepared_discard_passdown_pt2+0x4b/0x90 [dm_thin_pool]
[<ffffffffa0399611>] process_prepared+0x81/0xa0 [dm_thin_pool]
[<ffffffffa039e735>] do_worker+0xc5/0x820 [dm_thin_pool]
[<ffffffff8152bf54>] ? __schedule+0x244/0x680
[<ffffffff81087e72>] ? pwq_activate_delayed_work+0x42/0xb0
[<ffffffff81089f53>] process_one_work+0x153/0x3f0
[<ffffffff8108a71b>] worker_thread+0x12b/0x4b0
[<ffffffff8108a5f0>] ? rescuer_thread+0x350/0x350
[<ffffffff8108fd6a>] kthread+0xca/0xe0
[<ffffffff8108fca0>] ? kthread_park+0x60/0x60
[<ffffffff81530b45>] ret_from_fork+0x25/0x30

The fix is to first take the block ref count for discarded block and
then do a passdown discard of this block. If block ref count fails,
then bail out aborting current metadata transaction, mark pool as
PM_READ_ONLY and also free current thin mapping memory (existing error
handling code) without queueing this thin mapping onto next stage of
processing. If block ref count succeeds, then passdown discard of this
block. Discard callback of passdown_endio() will queue this thin mapping
onto next stage of processing.

Code flow with fix:
-> process_prepared_discard_passdown_pt1(m)
   -> dm_thin_remove_range()
   -> dm_pool_inc_data_range()
      --> if fails, free memory m and bail out
   -> discard passdown
      --> passdown_endio(m) queues m onto next stage

Cc: stable <stable@vger.kernel.org> # v4.9+
Reviewed-by: Eduardo Valentin <eduval@amazon.com>
Reviewed-by: Cristian Gafton <gafton@amazon.com>
Reviewed-by: Anchal Agarwal <anchalag@amazon.com>
Signed-off-by: Vallish Vaidyeshwara <vallish@amazon.com>
Reviewed-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-06-27 15:14:34 -04:00
Christoph Hellwig
4e4cbee93d block: switch bios to blk_status_t
Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-09 09:27:32 -06:00
Christoph Hellwig
1be5690984 dm: change ->end_io calling convention
Turn the error paramter into a pointer so that target drivers can change
the value, and make sure only DM_ENDIO_* values are returned from the
methods.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-09 09:27:32 -06:00
Linus Torvalds
d35a878ae1 - A major update for DM cache that reduces the latency for deciding
whether blocks should migrate to/from the cache.  The bio-prison-v2
   interface supports this improvement by enabling direct dispatch of
   work to workqueues rather than having to delay the actual work
   dispatch to the DM cache core.  So the dm-cache policies are much more
   nimble by being able to drive IO as they see fit.  One immediate
   benefit from the improved latency is a cache that should be much more
   adaptive to changing workloads.
 
 - Add a new DM integrity target that emulates a block device that has
   additional per-sector tags that can be used for storing integrity
   information.
 
 - Add a new authenticated encryption feature to the DM crypt target that
   builds on the capabilities provided by the DM integrity target.
 
 - Add MD interface for switching the raid4/5/6 journal mode and update
   the DM raid target to use it to enable aid4/5/6 journal write-back
   support.
 
 - Switch the DM verity target over to using the asynchronous hash crypto
   API (this helps work better with architectures that have access to
   off-CPU algorithm providers, which should reduce CPU utilization).
 
 - Various request-based DM and DM multipath fixes and improvements from
   Bart and Christoph.
 
 - A DM thinp target fix for a bio structure leak that occurs for each
   discard IFF discard passdown is enabled.
 
 - A fix for a possible deadlock in DM bufio and a fix to re-check the
   new buffer allocation watermark in the face of competing admin changes
   to the 'max_cache_size_bytes' tunable.
 
 - A couple DM core cleanups.
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Merge tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - A major update for DM cache that reduces the latency for deciding
   whether blocks should migrate to/from the cache. The bio-prison-v2
   interface supports this improvement by enabling direct dispatch of
   work to workqueues rather than having to delay the actual work
   dispatch to the DM cache core. So the dm-cache policies are much more
   nimble by being able to drive IO as they see fit. One immediate
   benefit from the improved latency is a cache that should be much more
   adaptive to changing workloads.

 - Add a new DM integrity target that emulates a block device that has
   additional per-sector tags that can be used for storing integrity
   information.

 - Add a new authenticated encryption feature to the DM crypt target
   that builds on the capabilities provided by the DM integrity target.

 - Add MD interface for switching the raid4/5/6 journal mode and update
   the DM raid target to use it to enable aid4/5/6 journal write-back
   support.

 - Switch the DM verity target over to using the asynchronous hash
   crypto API (this helps work better with architectures that have
   access to off-CPU algorithm providers, which should reduce CPU
   utilization).

 - Various request-based DM and DM multipath fixes and improvements from
   Bart and Christoph.

 - A DM thinp target fix for a bio structure leak that occurs for each
   discard IFF discard passdown is enabled.

 - A fix for a possible deadlock in DM bufio and a fix to re-check the
   new buffer allocation watermark in the face of competing admin
   changes to the 'max_cache_size_bytes' tunable.

 - A couple DM core cleanups.

* tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (50 commits)
  dm bufio: check new buffer allocation watermark every 30 seconds
  dm bufio: avoid a possible ABBA deadlock
  dm mpath: make it easier to detect unintended I/O request flushes
  dm mpath: cleanup QUEUE_IF_NO_PATH bit manipulation by introducing assign_bit()
  dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH
  dm: introduce enum dm_queue_mode to cleanup related code
  dm mpath: verify __pg_init_all_paths locking assumptions at runtime
  dm: verify suspend_locking assumptions at runtime
  dm block manager: remove an unused argument from dm_block_manager_create()
  dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue()
  dm mpath: delay requeuing while path initialization is in progress
  dm mpath: avoid that path removal can trigger an infinite loop
  dm mpath: split and rename activate_path() to prepare for its expanded use
  dm ioctl: prevent stack leak in dm ioctl call
  dm integrity: use previously calculated log2 of sectors_per_block
  dm integrity: use hex2bin instead of open-coded variant
  dm crypt: replace custom implementation of hex2bin()
  dm crypt: remove obsolete references to per-CPU state
  dm verity: switch to using asynchronous hash crypto API
  dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues
  ...
2017-05-03 10:31:20 -07:00
Dennis Yang
948f581a53 dm thin: fix a memory leak when passing discard bio down
dm-thin does not free the discard_parent bio after all chained sub
bios finished. The following kmemleak report could be observed after
pool with discard_passdown option processes discard bios in
linux v4.11-rc7. To fix this, we drop the discard_parent bio reference
when its endio (passdown_endio) called.

unreferenced object 0xffff8803d6b29700 (size 256):
  comm "kworker/u8:0", pid 30349, jiffies 4379504020 (age 143002.776s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    01 00 00 00 00 00 00 f0 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff81a5efd9>] kmemleak_alloc+0x49/0xa0
    [<ffffffff8114ec34>] kmem_cache_alloc+0xb4/0x100
    [<ffffffff8110eec0>] mempool_alloc_slab+0x10/0x20
    [<ffffffff8110efa5>] mempool_alloc+0x55/0x150
    [<ffffffff81374939>] bio_alloc_bioset+0xb9/0x260
    [<ffffffffa018fd20>] process_prepared_discard_passdown_pt1+0x40/0x1c0 [dm_thin_pool]
    [<ffffffffa018b409>] break_up_discard_bio+0x1a9/0x200 [dm_thin_pool]
    [<ffffffffa018b484>] process_discard_cell_passdown+0x24/0x40 [dm_thin_pool]
    [<ffffffffa018b24d>] process_discard_bio+0xdd/0xf0 [dm_thin_pool]
    [<ffffffffa018ecf6>] do_worker+0xa76/0xd50 [dm_thin_pool]
    [<ffffffff81086239>] process_one_work+0x139/0x370
    [<ffffffff810867b1>] worker_thread+0x61/0x450
    [<ffffffff8108b316>] kthread+0xd6/0xf0
    [<ffffffff81a6cd1f>] ret_from_fork+0x3f/0x70
    [<ffffffffffffffff>] 0xffffffffffffffff

Cc: stable@vger.kernel.org
Signed-off-by: Dennis Yang <dennisyang@qnap.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-04-24 14:58:10 -04:00
Christoph Hellwig
48920ff2a5 block: remove the discard_zeroes_data flag
Now that we use the proper REQ_OP_WRITE_ZEROES operation everywhere we can
kill this hack.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-08 11:25:38 -06:00
Joe Thornber
742c8fdc31 dm bio prison v2: new interface for the bio prison
The deferred set is gone and all methods have _v2 appended to the end of
their names to allow for continued use of the original bio prison in DM
thin-provisioning.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-03-07 11:30:16 -05:00
Jan Kara
dc3b17cc8b block: Use pointer to backing_dev_info from request_queue
We will want to have struct backing_dev_info allocated separately from
struct request_queue. As the first step add pointer to backing_dev_info
to request_queue and convert all users touching it. No functional
changes in this patch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02 08:20:48 -07:00
Christoph Hellwig
f73f44eb00 block: add a op_is_flush helper
This centralizes the checks for bios that needs to be go into the flush
state machine.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27 09:01:45 -07:00
Jens Axboe
1eff9d322a block: rename bio bi_rw to bi_opf
Since commit 63a4cc2486, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-07 14:41:02 -06:00
Joe Thornber
2a0fbffb1e dm thin: fix a race condition between discarding and provisioning a block
The discard passdown was being issued after the block was unmapped,
which meant the block could be reprovisioned whilst the passdown discard
was still in flight.

We can only identify unshared blocks (safe to do a passdown a discard
to) once they're unmapped and their ref count hits zero.  Block ref
counts are now used to guard against concurrent allocation of these
blocks that are being discarded.  So now we unmap the block, issue
passdown discards, and the immediately increment ref counts for regions
that have been discarded via passed down (this is safe because
allocation occurs within the same thread).  We then decrement ref counts
once the passdown discard IO is complete -- signaling these blocks may
now be allocated.

This fixes the potential for corruption that was reported here:
https://www.redhat.com/archives/dm-devel/2016-June/msg00311.html

Reported-by: Dennis Yang <dennisyang@qnap.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-07-20 12:43:35 -04:00
Mike Christie
28a8f0d317 block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSH
To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Mike Christie
e6047149db dm: use bio op accessors
Separate the op from the rq_flag_bits and have dm
set/get the bio using bio_set_op_attrs/bio_op.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Mike Christie
469e3216e2 block discard: use bio set op accessor
This converts the block issue discard helper and users to use
the bio_set_op_attrs accessor and only pass in the operation flags
like REQ_SEQURE.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Mike Christie
4e49ea4a3d block/fs/drivers: remove rw argument from submit_bio
This has callers of submit_bio/submit_bio_wait set the bio->bi_rw
instead of passing it in. This makes that use the same as
generic_make_request and how we set the other bio fields.

Signed-off-by: Mike Christie <mchristi@redhat.com>

Fixed up fs/ext4/crypto.c

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Joe Thornber
202bae5293 dm thin: unroll issue_discard() to create longer discard bio chains
There is little benefit to doing this but it does structure DM thinp's
code to more cleanly use the __blkdev_issue_discard() interface --
particularly in passdown_double_checking_shared_status().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-05-13 09:04:20 -04:00
Mike Snitzer
3dba53a958 dm thin: use __blkdev_issue_discard for async discard support
With commit 38f2525533 ("block: add __blkdev_issue_discard") DM thinp
no longer needs to carry its own async discard method.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-05-13 09:03:52 -04:00
Mike Snitzer
13e4f8a695 dm thin: remove __bio_inc_remaining() and switch to using bio_inc_remaining()
DM thinp's use of bio_inc_remaining() is critical to ensure the original
parent discard bio isn't completed before sub-discards have.  DM thinp
needs this due to the extra quiescing that occurs, via multiple DM thinp
mappings, while processing large discards.  As such DM thinp must build
the async discard bio chain after some delay -- so bio_inc_remaining()
is used to enable DM thinp to take a reference on the original parent
discard bio for each mapping.  This allows the immediate use of
bio_endio() on that discard bio; but with the understanding that the
actual completion won't occur until each of the sub-discards'
per-mapping references are dropped.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2016-05-13 09:03:52 -04:00
Amitoj Kaur Chawla
813923b1a2 dm thin: Remove return statement from void function
Return statement at the end of a void function is useless.

The Coccinelle semantic patch used to make this change is as follows:
//<smpl>
@@
identifier f;
expression e;
@@
void f(...) {
<...
- return
  e;
...>
}
//</smpl>

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-05-05 15:25:50 -04:00
Mike Snitzer
c3667cc619 dm thin: consistently return -ENOSPC if pool has run out of data space
Commit 0a927c2f02 ("dm thin: return -ENOSPC when erroring retry list due
to out of data space") was a step in the right direction but didn't go
far enough.

Add a new 'out_of_data_space' flag to 'struct pool' and set it if/when
the pool runs of of data space.  This fixes cell_error() and
error_retry_list() to not blindly return -EIO.

We cannot rely on the 'error_if_no_space' feature flag since it is
transient (in that it can be reset once space is added, plus it only
controls whether errors are issued, it doesn't reflect whether the
pool is actually out of space).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-11 16:15:22 -05:00
Mike Snitzer
30187e1d48 dm: rename target's per_bio_data_size to per_io_data_size
Request-based DM will also make use of per_bio_data_size.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22 22:34:37 -05:00
Mike Snitzer
1c2e54e1ed dm thin: bump thin and thin-pool target versions
Commit 3d5f6733 ("dm thin metadata: speed up discard of partially mapped
volumes"), or some other dm-thinp change during the Linux 4.5
development window, really should've bumped these target versions.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-01-06 20:59:40 -05:00
Nikolay Borisov
18d03e8c25 dm thin: fix race condition when destroying thin pool workqueue
When a thin pool is being destroyed delayed work items are
cancelled using cancel_delayed_work(), which doesn't guarantee that on
return the delayed item isn't running.  This can cause the work item to
requeue itself on an already destroyed workqueue.  Fix this by using
cancel_delayed_work_sync() which guarantees that on return the work item
is not running anymore.

Fixes: 905e51b39a ("dm thin: commit outstanding data every second")
Fixes: 85ad643b7e ("dm thin: add timeout to stop out-of-data-space mode holding IO forever")
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-12-17 15:47:20 -05:00
Mike Snitzer
0fcb04d593 dm thin: fix regression in advertised discard limits
When establishing a thin device's discard limits we cannot rely on the
underlying thin-pool device's discard capabilities (which are inherited
from the thin-pool's underlying data device) given that DM thin devices
must provide discard support even when the thin-pool's underlying data
device doesn't support discards.

Users were exposed to this thin device discard limits regression if
their thin-pool's underlying data device does _not_ support discards.
This regression caused all upper-layers that called the
blkdev_issue_discard() interface to not be able to issue discards to
thin devices (because discard_granularity was 0).  This regression
wasn't caught earlier because the device-mapper-test-suite's extensive
'thin-provisioning' discard tests are only ever performed against
thin-pool's with data devices that support discards.

Fix is to have thin_io_hints() test the pool's 'discard_enabled' feature
rather than inferring whether or not a thin device's discard support
should be enabled by looking at the thin-pool's discard_granularity.

Fixes: 216076705 ("dm thin: disable discard support for thin devices if pool's is disabled")
Reported-by: Mike Gerber <mike@sprachgewalt.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.1+
2015-11-23 14:54:46 -05:00
Mike Snitzer
172c238612 dm thin: restore requested 'error_if_no_space' setting on OODS to WRITE transition
A thin-pool that is in out-of-data-space (OODS) mode may transition back
to write mode -- without the admin adding more space to the thin-pool --
if/when blocks are released (either by deleting thin devices or
discarding provisioned blocks).

But as part of the thin-pool's earlier transition to out-of-data-space
mode the thin-pool may have set the 'error_if_no_space' flag to true if
the no_space_timeout expires without more space having been made
available.  That implementation detail, of changing the pool's
error_if_no_space setting, needs to be reset back to the default that
the user specified when the thin-pool's table was loaded.

Otherwise we'll drop the user requested behaviour on the floor when this
out-of-data-space to write mode transition occurs.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Fixes: 2c43fd26e4 ("dm thin: fix missing out-of-data-space to write mode transition if blocks are released")
Cc: stable@vger.kernel.org
2015-11-16 09:36:08 -05:00
Mike Snitzer
ba30670f4d dm thin: fix missing pool reference count decrement in pool_ctr error path
Fixes: ac8c3f3df ("dm thin: generate event when metadata threshold passed")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.10+
2015-10-13 12:20:55 -04:00
Mike Snitzer
216076705d dm thin: disable discard support for thin devices if pool's is disabled
If the pool is configured with 'ignore_discard' its discard support is
disabled.  The pool's thin devices should also have queue_limits that
reflect discards are disabled.

Fixes: 34fbcf62 ("dm thin: range discard support")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.1+
2015-09-13 21:32:10 -04:00
Linus Torvalds
1e1a4e8f43 Merge tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper update from Mike Snitzer:

 - a couple small cleanups in dm-cache, dm-verity, persistent-data's
   dm-btree, and DM core.

 - a 4.1-stable fix for dm-cache that fixes the leaking of deferred bio
   prison cells

 - a 4.2-stable fix that adds feature reporting for the dm-stats
   features added in 4.2

 - improve DM-snapshot to not invalidate the on-disk snapshot if
   snapshot device write overflow occurs; but a write overflow triggered
   through the origin device will still invalidate the snapshot.

 - optimize DM-thinp's async discard submission a bit now that late bio
   splitting has been included in block core.

 - switch DM-cache's SMQ policy lock from using a mutex to a spinlock;
   improves performance on very low latency devices (eg. NVMe SSD).

 - document DM RAID 4/5/6's discard support

[ I did not pull the slab changes, which weren't appropriate for this
  tree, and weren't obviously the right thing to do anyway.  At the very
  least they need some discussion and explanation before getting merged.

  Because not pulling the actual tagged commit but doing a partial pull
  instead, this merge commit thus also obviously is missing the git
  signature from the original tag ]

* tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: fix use after freeing migrations
  dm cache: small cleanups related to deferred prison cell cleanup
  dm cache: fix leaking of deferred bio prison cells
  dm raid: document RAID 4/5/6 discard support
  dm stats: report precise_timestamps and histogram in @stats_list output
  dm thin: optimize async discard submission
  dm snapshot: don't invalidate on-disk image on snapshot write overflow
  dm: remove unlikely() before IS_ERR()
  dm: do not override error code returned from dm_get_device()
  dm: test return value for DM_MAPIO_SUBMITTED
  dm verity: remove unused mempool
  dm cache: move wake_waker() from free_migrations() to where it is needed
  dm btree remove: remove unused function get_nr_entries()
  dm btree: remove unused "dm_block_t root" parameter in btree_split_sibling()
  dm cache policy smq: change the mutex to a spinlock
2015-09-02 16:35:26 -07:00
Linus Torvalds
1081230b74 Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
 "This first core part of the block IO changes contains:

   - Cleanup of the bio IO error signaling from Christoph.  We used to
     rely on the uptodate bit and passing around of an error, now we
     store the error in the bio itself.

   - Improvement of the above from myself, by shrinking the bio size
     down again to fit in two cachelines on x86-64.

   - Revert of the max_hw_sectors cap removal from a revision again,
     from Jeff Moyer.  This caused performance regressions in various
     tests.  Reinstate the limit, bump it to a more reasonable size
     instead.

   - Make /sys/block/<dev>/queue/discard_max_bytes writeable, by me.
     Most devices have huge trim limits, which can cause nasty latencies
     when deleting files.  Enable the admin to configure the size down.
     We will look into having a more sane default instead of UINT_MAX
     sectors.

   - Improvement of the SGP gaps logic from Keith Busch.

   - Enable the block core to handle arbitrarily sized bios, which
     enables a nice simplification of bio_add_page() (which is an IO hot
     path).  From Kent.

   - Improvements to the partition io stats accounting, making it
     faster.  From Ming Lei.

   - Also from Ming Lei, a basic fixup for overflow of the sysfs pending
     file in blk-mq, as well as a fix for a blk-mq timeout race
     condition.

   - Ming Lin has been carrying Kents above mentioned patches forward
     for a while, and testing them.  Ming also did a few fixes around
     that.

   - Sasha Levin found and fixed a use-after-free problem introduced by
     the bio->bi_error changes from Christoph.

   - Small blk cgroup cleanup from Viresh Kumar"

* 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits)
  blk: Fix bio_io_vec index when checking bvec gaps
  block: Replace SG_GAPS with new queue limits mask
  block: bump BLK_DEF_MAX_SECTORS to 2560
  Revert "block: remove artifical max_hw_sectors cap"
  blk-mq: fix race between timeout and freeing request
  blk-mq: fix buffer overflow when reading sysfs file of 'pending'
  Documentation: update notes in biovecs about arbitrarily sized bios
  block: remove bio_get_nr_vecs()
  fs: use helper bio_add_page() instead of open coding on bi_io_vec
  block: kill merge_bvec_fn() completely
  md/raid5: get rid of bio_fits_rdev()
  md/raid5: split bio for chunk_aligned_read
  block: remove split code in blkdev_issue_{discard,write_same}
  btrfs: remove bio splitting and merge_bvec_fn() calls
  bcache: remove driver private bio splitting code
  block: simplify bio_add_page()
  block: make generic_make_request handle arbitrarily sized bios
  blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL)
  block: don't access bio->bi_error after bio_put()
  block: shrink struct bio down to 2 cache lines again
  ...
2015-09-02 13:10:25 -07:00
Mike Snitzer
84f8bd86cc dm thin: optimize async discard submission
__blkdev_issue_discard_async() doesn't need to worry about further
splitting because the upper layer blkdev_issue_discard() will have
already handled splitting bios such that the bi_size isn't
overflowed.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2015-08-18 11:36:11 -04:00
Kent Overstreet
8ae126660f block: kill merge_bvec_fn() completely
As generic_make_request() is now able to handle arbitrarily sized bios,
it's no longer necessary for each individual block driver to define its
own ->merge_bvec_fn() callback. Remove every invocation completely.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@kernel.org>
Cc: ceph-devel@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md' bits)
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: also remove ->merge_bvec_fn() in dm-thin as well as
 dm-era-target, and resolve merge conflicts]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-13 12:31:57 -06:00
Christoph Hellwig
4246a0b63b block: add a bi_error field to struct bio
Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-29 08:55:15 -06:00
Mike Snitzer
0a927c2f02 dm thin: return -ENOSPC when erroring retry list due to out of data space
Otherwise -EIO would be returned when -ENOSPC should be used
consistently.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-26 17:39:19 -04:00
Mike Snitzer
e4c78e210d dm thin: display 'needs_check' in status if it is set
There is currently no way to see that the needs_check flag has been set
in the metadata.  Display 'needs_check' in the thin-pool status if it is
set in the thinp metadata.

Also, update thinp documentation.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 10:23:50 -04:00
Mike Snitzer
bcc696fac1 dm thin: stay in out-of-data-space mode once no_space_timeout expires
This fixes an issue where running out of data space would cause the
thin-pool's metadata to become read-only.  There was no reason to make
metadata read-only -- calling set_pool_mode() with PM_READ_ONLY was a
misguided way to error all queued and future write IOs.  We can
accomplish the same by degrading from PM_OUT_OF_DATA_SPACE to
PM_OUT_OF_DATA_SPACE with error_if_no_space enabled.

Otherwise, the use of PM_READ_ONLY could cause a race where commit() was
started before the PM_READ_ONLY transition but dm_pool_commit_metadata()
would go on to fail because the block manager had transitioned to
read-only.  The return of -EPERM from dm_pool_commit_metadata(), due to
attempting to commit while in read-only mode, caused the thin-pool to
set 'needs_check' because a metadata_operation_failed().  This needless
cascade of failures makes life for users more difficult than needed.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 10:23:49 -04:00
Joe Thornber
a822c83e47 dm thin: allocate the cell_sort_array dynamically
Given the pool's cell_sort_array holds 8192 pointers it triggers an
order 5 allocation via kmalloc.  This order 5 allocation is prone to
failure as system memory gets more fragmented over time.

Fix this by allocating the cell_sort_array using vmalloc.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-07-05 21:59:37 -04:00
Mike Snitzer
fd467696e8 dm thin: fail messages with EOPNOTSUPP when pool cannot handle messages
Use EOPNOTSUPP, rather than EINVAL, error code when user attempts to
send the pool a message.  Otherwise usespace is led to believe the
message failed due to invalid argument.

Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-06-11 17:13:05 -04:00
Joe Thornber
34fbcf6257 dm thin: range discard support
Previously REQ_DISCARD bios have been split into block sized chunks
before submission to the thin target.  There are a couple of issues with
this:

 - If the block size is small, a large discard request can
   get broken up into a great many bios which is both slow and causes
   a lot of memory pressure.

 - The thin pool block size and the discard granularity for the
   underlying data device need to be compatible if we want to passdown
   the discard.

This patch relaxes the block size granularity for thin devices.  It
makes use of the recent range locking added to the bio_prison to
quiesce a whole range of thin blocks before unmapping them.  Once a
thin range has been unmapped the discard can then be passed down to
the data device for those sub ranges where the data blocks are no
longer used (ie. they weren't shared in the first place).

This patch also doesn't make any apologies about open-coding portions
of block core as a means to supporting async discard completions in the
near-term -- if/when late bio splitting lands it'll all get cleaned up.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-06-11 17:13:05 -04:00
Mike Snitzer
f8ae75253e dm thin: cleanup schedule_zero() to read more logically
The overwrite has only ever about optimizing away the need to zero a
block if the entire block was being overwritten.  As such it is only
relevant when zeroing is enabled.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
2015-05-29 14:18:58 -04:00
Mike Snitzer
8b908f8e94 dm thin: cleanup overwrite's endio restore to be centralized
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:58 -04:00
Mike Snitzer
326e1dbb57 block: remove management of bi_remaining when restoring original bi_end_io
Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for
non-chains") regressed all existing callers that followed this pattern:
 1) saving a bio's original bi_end_io
 2) wiring up an intermediate bi_end_io
 3) restoring the original bi_end_io from intermediate bi_end_io
 4) calling bio_endio() to execute the restored original bi_end_io

The regression was due to BIO_CHAIN only ever getting set if
bio_inc_remaining() is called.  For the above pattern it isn't set until
step 3 above (step 2 would've needed to establish BIO_CHAIN).  As such
the first bio_endio(), in step 2 above, never decremented __bi_remaining
before calling the intermediate bi_end_io -- leaving __bi_remaining with
the value 1 instead of 0.  When bio_inc_remaining() occurred during step
3 it brought it to a value of 2.  When the second bio_endio() was
called, in step 4 above, it should've called the original bi_end_io but
it didn't because there was an extra reference that wasn't dropped (due
to atomic operations being optimized away since BIO_CHAIN wasn't set
upfront).

Fix this issue by removing the __bi_remaining management complexity for
all callers that use the above pattern -- bio_chain() is the only
interface that _needs_ to be concerned with __bi_remaining.  For the
above pattern callers just expect the bi_end_io they set to get called!
Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls
that aren't associated with the bio_chain() interface.

Also, the bio_inc_remaining() interface has been moved local to bio.c.

Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-22 08:58:55 -06:00
Jens Axboe
c4cf5261f8 bio: skip atomic inc/dec of ->bi_remaining for non-chains
Struct bio has an atomic ref count for chained bio's, and we use this
to know when to end IO on the bio. However, most bio's are not chained,
so we don't need to always introduce this atomic operation as part of
ending IO.

Add a helper to elevate the bi_remaining count, and flag the bio as
now actually needing the decrement at end_io time. Rename the field
to __bi_remaining to catch any current users of this doing the
incrementing manually.

For high IOPS workloads, this reduces the overhead of bio_endio()
substantially.

Tested-by: Robert Elliott <elliott@hp.com>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05 13:32:47 -06:00
Joe Thornber
5f027a3bf1 dm thin: fix to consistently zero-fill reads to unprovisioned blocks
It was always intended that a read to an unprovisioned block will return
zeroes regardless of whether the pool is in read-only or read-write
mode.  thin_bio_map() was inconsistent with its handling of such reads
when the pool is in read-only mode, it now properly zero-fills the bios
it returns in response to unprovisioned block reads.

Eliminate thin_bio_map()'s special read-only mode handling of -ENODATA
and just allow the IO to be deferred to the worker which will result in
pool->process_bio() handling the IO (which already properly zero-fills
reads to unprovisioned blocks).

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-02-27 09:59:12 -05:00
Linus Torvalds
802ea9d864 - Most significant change this cycle is request-based DM now supports
stacking ontop of blk-mq devices.  This blk-mq support changes the
   model request-based DM uses for cloning a request to relying on
   calling blk_get_request() directly from the underlying blk-mq device.
   Early consumer of this code is Intel's emerging NVMe hardware; thanks
   to Keith Busch for working on, and pushing for, these changes.
 
 - A few other small fixes and cleanups across other DM targets.
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Merge tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper changes from Mike Snitzer:

 - The most significant change this cycle is request-based DM now
   supports stacking ontop of blk-mq devices.  This blk-mq support
   changes the model request-based DM uses for cloning a request to
   relying on calling blk_get_request() directly from the underlying
   blk-mq device.

   An early consumer of this code is Intel's emerging NVMe hardware;
   thanks to Keith Busch for working on, and pushing for, these changes.

 - A few other small fixes and cleanups across other DM targets.

* tag 'dm-3.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: inherit QUEUE_FLAG_SG_GAPS flags from underlying queues
  dm snapshot: remove unnecessary NULL checks before vfree() calls
  dm mpath: simplify failure path of dm_multipath_init()
  dm thin metadata: remove unused dm_pool_get_data_block_size()
  dm ioctl: fix stale comment above dm_get_inactive_table()
  dm crypt: update url in CONFIG_DM_CRYPT help text
  dm bufio: fix time comparison to use time_after_eq()
  dm: use time_in_range() and time_after()
  dm raid: fix a couple integer overflows
  dm table: train hybrid target type detection to select blk-mq if appropriate
  dm: allocate requests in target when stacking on blk-mq devices
  dm: prepare for allocating blk-mq clone requests in target
  dm: submit stacked requests in irq enabled context
  dm: split request structure out from dm_rq_target_io structure
  dm: remove exports for request-based interfaces without external callers
2015-02-12 16:36:31 -08:00
Manuel Schölling
0f30af98cb dm: use time_in_range() and time_after()
To be future-proof and for better readability the time comparisons are modified
to use time_in_range() and time_after() instead of plain, error-prone math.

Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:48 -05:00
Joe Thornber
2a7eaea02b dm thin: don't allow messages to be sent to a pool target in READ_ONLY or FAIL mode
You can't modify the metadata in these modes.  It's better to fail these
messages immediately than let the block-manager deny write locks on
metadata blocks.  Otherwise these failed metadata changes will trigger
'needs_check' to get set in the metadata superblock -- requiring repair
using the thin_check utility.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-01-28 10:00:34 -05:00
Marc Dionne
2b94e8960c dm thin: fix crash by initializing thin device's refcount and completion earlier
Commit 80e96c5484 ("dm thin: do not allow thin device activation
while pool is suspended") delayed the initialization of a new thin
device's refcount and completion until after this new thin was added
to the pool's active_thins list and the pool lock is released.  This
opens a race with a worker thread that walks the list and calls
thin_get/put, noticing that the refcount goes to 0 and calling
complete, freezing up the system and giving the oops below:

 kernel: BUG: unable to handle kernel NULL pointer dereference at           (null)
 kernel: IP: [<ffffffff810d360b>] __wake_up_common+0x2b/0x90

 kernel: Call Trace:
 kernel: [<ffffffff810d3683>] __wake_up_locked+0x13/0x20
 kernel: [<ffffffff810d3dc7>] complete+0x37/0x50
 kernel: [<ffffffffa0595c50>] thin_put+0x20/0x30 [dm_thin_pool]
 kernel: [<ffffffffa059aab7>] do_worker+0x667/0x870 [dm_thin_pool]
 kernel: [<ffffffff816a8a4c>] ? __schedule+0x3ac/0x9a0
 kernel: [<ffffffff810b1aef>] process_one_work+0x14f/0x400
 kernel: [<ffffffff810b206b>] worker_thread+0x6b/0x490
 kernel: [<ffffffff810b2000>] ? rescuer_thread+0x260/0x260
 kernel: [<ffffffff810b6a7b>] kthread+0xdb/0x100
 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170
 kernel: [<ffffffff816ad7ec>] ret_from_fork+0x7c/0xb0
 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170

Set the thin device's initial refcount and initialize the completion
before adding it to the pool's active_thins list in thin_ctr().

Signed-off-by: Marc Dionne <marc.dionne@your-file-system.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-17 12:06:25 -05:00
Joe Thornber
2c43fd26e4 dm thin: fix missing out-of-data-space to write mode transition if blocks are released
Discard bios and thin device deletion have the potential to release data
blocks.  If the thin-pool is in out-of-data-space mode, and blocks were
released, transition the thin-pool back to full write mode.

The correct time to do this is just after the thin-pool metadata commit.
It cannot be done before the commit because the space maps will not
allow immediate reuse of the data blocks in case there's a rollback
following power failure.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-17 11:59:36 -05:00
Joe Thornber
45ec9bd0fd dm thin: fix inability to discard blocks when in out-of-data-space mode
When the pool was in PM_OUT_OF_SPACE mode its process_prepared_discard
function pointer was incorrectly being set to
process_prepared_discard_passdown rather than process_prepared_discard.

This incorrect function pointer meant the discard was being passed down,
but not effecting the mapping.  As such any discard that was issued, in
an attempt to reclaim blocks, would not successfully free data space.

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-17 11:59:36 -05:00
Mike Snitzer
d200c30ef0 dm thin: fix pool_io_hints to avoid looking at max_hw_sectors
Simplify the pool_io_hints code that works to establish a max_sectors
value that is a power-of-2 factor of the thin-pool's blocksize.  The
biggest associated improvement is that the DM thin-pool is no longer
concerning itself with the data device's max_hw_sectors when adjusting
max_sectors.

This fixes the relative fragility of the original "dm thin: adjust
max_sectors_kb based on thinp blocksize" commit that only became
apparent when testing was performed using a DM thin-pool ontop of a
virtio_blk device.  One proposed upstream patch detailed the problems
inherent in virtio_blk: https://lkml.org/lkml/2014/11/20/611

So even though virtio_blk incorrectly set its max_hw_sectors it actually
helped make it clear that we need DM thinp to be tolerant of any future
Linux driver that incorrectly sets max_hw_sectors.

We only need to be concerned with modifying the thin-pool device's
max_sectors limit if it is smaller than the thin-pool's blocksize.  In
this case the value of max_sectors does become a limiting factor when
upper layers (e.g. filesystems) construct their bios.  But if the
hardware can support IOs larger than the thin-pool's blocksize the user
is encouraged to adjust the thin-pool's data device's max_sectors
accordingly -- doing so will enable the thin-pool to inherit the
established user-defined max_sectors.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-21 12:54:23 -05:00
Mike Snitzer
583024d248 dm thin: suspend/resume active thin devices when reloading thin-pool
Before this change it was expected that userspace would first suspend
all active thin devices, reload/resize the thin-pool target, then resume
all active thin devices.  Now the thin-pool suspend/resume will trigger
the suspend/resume of all active thins via appropriate calls to
dm_internal_suspend and dm_internal_resume.

Store the mapped_device for each thin device in struct thin_c to make
these calls possible.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-11-19 12:34:08 -05:00
Mike Snitzer
80e96c5484 dm thin: do not allow thin device activation while pool is suspended
Otherwise IO could be issued to the pool while it is suspended.

Care was taken to properly interlock between the thin and thin-pool
targets when accessing the pool's 'suspended' flag.  The thin_ctr will
not add a new thin device to the pool's active_thins list if the pool is
susepended.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-11-19 11:25:36 -05:00
Mike Snitzer
5ec02084f6 dm thin: remove stale 'trim' message in block comment above pool_message
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-12 20:15:05 -05:00
Mikulas Patocka
17181fb7a0 dm thin: fix a race in thin_dtr
As long as struct thin_c is in the list, anyone can grab a reference of
it.  Consequently, we must wait for the reference count to drop to zero
*after* we remove the structure from the list, not before.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-12 20:15:04 -05:00
Joe Thornber
5f274d8865 dm bio prison: introduce support for locking ranges of blocks
Ranges will be placed in the same cell if they overlap.

Range locking is a prerequisite for more efficient multi-block discard
support in both the cache and thin-provisioning targets.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Mike Snitzer
42d6a8ce3c dm thin: refactor requeue_io to eliminate spinlock bouncing
Also refactor some other bio_list erroring helpers.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:29 -05:00
Mike Snitzer
9d094eebd7 dm thin: optimize retry_bios_on_resume
Eliminate redundant should_error_unserviceable_bio check and error
loop.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
ac4c3f34a9 dm thin: sort the deferred cells
Sort the cells in logical block order before processing each cell in
process_thin_deferred_cells().  This significantly improves the ondisk
layout on rotational storage, whereby improving read performance.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
23ca2bb6c6 dm thin: direct dispatch when breaking sharing
This use of direct submission in process_shared_bio() reduces latency
for submitting bios in the shared cell by avoiding adding those bios to
the deferred list and waiting for the next iteration of the worker.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
2d759a46b4 dm thin: remap the bios in a cell immediately
This use of direct submission in process_prepared_mapping() reduces
latency for submitting bios in a cell by avoiding adding those bios to
the deferred list and waiting for the next iteration of the worker.

But this direct submission exposes the potential for a race between
releasing a cell and incrementing deferred set.  Fix this by introducing
dm_cell_visit_release() and refactoring inc_remap_and_issue_cell()
accordingly.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
a374bb217b dm thin: defer whole cells rather than individual bios
This avoids dropping the cell, so increases the probability that other
bios will collect within the cell, rather than being passed individually
to the worker.

Also add required process_cell and process_discard_cell error handling
wrappers and set associated pool-mode function pointers accordingly.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Mike Snitzer
452d7a620d dm thin: factor out remap_and_issue_overwrite
Purely cleanup of duplicated code, no functional change.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:28 -05:00
Joe Thornber
7a7e97ca58 dm thin: performance improvement to discard processing
When processing a discard bio, if the block is already quiesced do the
discard immediately rather than adding the mapping to a list for the
next iteration of the worker thread.

Discarding a fully provisioned 100G thin volume with 64k block size goes
from 860s to 95s with this change.

Clearly there's something wrong with the worker architecture, more
investigation needed.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Mike Snitzer
36f12aeb71 dm thin: implement thin_merge
Introduce thin_merge so that any additional constraints from the data
volume may be taken into account when determing the maximum number of
sectors that can be issued relative to the specified logical offset.

This is particularly important if/when the data volume is layered ontop
of a more sophisticated device (e.g. dm-raid or some other DM target).

Reviewed-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Mike Snitzer
604ea90641 dm thin: adjust max_sectors_kb based on thinp blocksize
Allows for filesystems to submit bios that are a factor of the thinp
blocksize, improving dm-thinp efficiency (particularly when the data
volume is RAID).

Also set io_min to max_sectors_kb if it is a factor of the thinp
blocksize.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Joe Thornber
7d327fe051 dm thin: throttle incoming IO
Throttle IO based on the time it's taking the worker to do one loop.
There were reports of hung task timeouts occuring and it was observed
that the excessively long avgqu-sz (as reported by iostat) was
contributing to these hung tasks.

Throttling definitely helps dm-thinp perform better under heavy IO load
(without being detremental by being overzealous).  It reduces avgqu-sz
drastically, e.g.: from 60K to ~6K, and even as low as 150 once metadata
is cached by bufio, when dirty_ratio=5, dirty_background_ratio=2.  And
avgqu-sz stays at or below 30K even with dirty_ratio=20,
dirty_background_ratio=10.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Joe Thornber
8a01a6af75 dm thin: prefetch missing metadata pages
Prefetch metadata at the start of the worker thread and then again every
128th bio processed from the deferred list.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:27 -05:00
Joe Thornber
a195db2d29 dm bio prison: switch to using a red black tree
Previously it was using a fixed sized hash table.  There are times
when very many concurrent cells are held (such as when processing a very
large discard).  When this happens the hash table performance becomes
very poor.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Joe Thornber
c822ed967c dm thin: grab a virtual cell before looking up the mapping
Avoids normal IO racing with discard.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-11-04 13:05:53 -05:00
Mike Snitzer
fdfb4c8c1a dm thin: set minimum_io_size to pool's data block size
Before, if the block layer's limit stacking didn't establish an
optimal_io_size that was compatible with the thin-pool's data block size
we'd set optimal_io_size to the data block size and minimum_io_size to 0
(which the block layer adjusts to be physical_block_size).

Update pool_io_hints() to set both minimum_io_size and optimal_io_size
to the thin-pool's data block size.  This fixes an issue reported where
mkfs.xfs would create more XFS Allocation Groups on thinp volumes than
on a normal linear LV of comparable size, see:
https://bugzilla.redhat.com/show_bug.cgi?id=1003227

Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-08-01 12:30:35 -04:00
Joe Thornber
e5aea7b49f dm thin: relax external origin size constraints
Track the size of any external origin.  Previously the external origin's
size had to be a multiple of the thin-pool's block size, that is no
longer a requirement.  In addition, snapshots that are larger than the
external origin are now supported.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-08-01 12:30:32 -04:00
Joe Thornber
50f3c3efdd dm thin: switch to an atomic_t for tracking pending new block preparations
Previously we used separate boolean values to track quiescing and
copying actions.  By switching to an atomic_t we can support blocks that
need a partial copy and partial zero.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-08-01 12:30:31 -04:00
Lukas Czerner
09869de57e dm thin: update discard_granularity to reflect the thin-pool blocksize
DM thinp already checks whether the discard_granularity of the data
device is a factor of the thin-pool block size.  But when using the
dm-thin-pool's discard passdown support, DM thinp was not selecting the
max of the underlying data device's discard_granularity and the
thin-pool's block size.

Update set_discard_limits() to set discard_granularity to the max of
these values.  This enables blkdev_issue_discard() to properly align the
discards that are sent to the DM thin device on a full block boundary.
As such each discard will now cover an entire DM thin-pool block and the
block will be reclaimed.

Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-06-11 16:56:12 -04:00