linux-toradex.git/include/linux/drbd.h, branch v5.1-rc1

drbd: introduce P_ZEROES (REQ_OP_WRITE_ZEROES on the "wire")

2018-12-20T16:51:31+00:00

And also re-enable partial-zero-out + discard aligned.

With the introduction of REQ_OP_WRITE_ZEROES,
we started to use that for both WRITE_ZEROES and DISCARDS,
hoping that WRITE_ZEROES would "do what we want",
UNMAP if possible, zero-out the rest.

The example scenario is some LVM "thin" backend.

While an un-allocated block on dm-thin reads as zeroes, on a dm-thin
with "skip_block_zeroing=true", after a partial block write allocated
that block, that same block may well map "undefined old garbage" from
the backends on LBAs that have not yet been written to.

If we cannot distinguish between zero-out and discard on the receiving
side, to avoid "undefined old garbage" to pop up randomly at later times
on supposedly zero-initialized blocks, we'd need to map all discards to
zero-out on the receiving side.  But that would potentially do a full
alloc on thinly provisioned backends, even when the expectation was to
unmap/trim/discard/de-allocate.

We need to distinguish on the protocol level, whether we need to guarantee
zeroes (and thus use zero-out, potentially doing the mentioned full-alloc),
or if we want to put the emphasis on discard, and only do a "best effort
zeroing" (by "discarding" blocks aligned to discard-granularity, and zeroing
only potential unaligned head and tail clippings to at least *try* to
avoid "false positives" in an online-verify later), hoping that someone
set skip_block_zeroing=false.

For some discussion regarding this on dm-devel, see also
https://www.mail-archive.com/dm-devel%40redhat.com/msg07965.html
https://www.redhat.com/archives/dm-devel/2018-January/msg00271.html

For backward compatibility, P_TRIM means zero-out, unless the
DRBD_FF_WZEROES feature flag is agreed upon during handshake.

To have upper layers even try to submit WRITE ZEROES requests,
we need to announce "efficient zeroout" independently.

We need to fixup max_write_zeroes_sectors after blk_queue_stack_limits():
if we can handle "zeroes" efficiently on the protocol,
we want to do that, even if our backend does not announce
max_write_zeroes_sectors itself.

Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: switch from kmalloc() to kmalloc_array()

2017-08-29T21:34:46+00:00

We had one call to kmalloc that actually allocates an array. Switch that
one to the kmalloc_array() function.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: correctly handle failed crypto_alloc_hash

2016-06-14T03:43:08+00:00

crypto_alloc_hash returns an ERR_PTR(), not NULL.

Also reset peer_integrity_tfm to NULL, to not call crypto_free_hash()
on an errno in the cleanup path.

Reported-by: Insu Yun 

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: code cleanups without semantic changes

2016-06-14T03:43:07+00:00

This contains various cosmetic fixes ranging from simple typos to
const-ifying, and using booleans properly.

Original commit messages from Fabian's patch set:
drbd: debugfs: constify drbd_version_fops
drbd: use seq_put instead of seq_print where possible
drbd: include linux/uaccess.h instead of asm/uaccess.h
drbd: use const char * const for drbd strings
drbd: kerneldoc warning fix in w_e_end_data_req()
drbd: use unsigned for one bit fields
drbd: use bool for peer is_ states
drbd: fix typo
drbd: use | for bitmask combination
drbd: use true/false for bool
drbd: fix drbd_bm_init() comments
drbd: introduce peer state union
drbd: fix maybe_pull_ahead() locking comments
drbd: use bool for growing
drbd: remove redundant declarations
drbd: replace if/BUG by BUG_ON

Signed-off-by: Fabian Frederick 
Signed-off-by: Roland Kammerer 
Signed-off-by: Jens Axboe

drbd: make drbd known to lsblk: use bd_link_disk_holder

2015-11-25T16:22:02+00:00

lsblk should be able to pick up stacking device driver relations
involving DRBD conveniently.

Even though upstream kernel since 2011 says
	"DON'T USE THIS UNLESS YOU'RE ALREADY USING IT."
a new user has been added since (bcache),
which sets the precedences for us to use it as well.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: drop remnants of connector -- we don't use it anymore in drbd 8.4

2015-11-25T16:22:01+00:00

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: Backport the "events2" command

2015-11-25T16:22:00+00:00

The events2 command originates from drbd-9 development. It features
more information but requires a incompatible change in output
format.
Therefore the previous events command continues to exist, the new
improved events2 command becomes available now.

This prepares the user-base for a later switch to the complete
drbd9 code base.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: Move enum write_ordering_e to drbd.h

2015-11-25T16:22:00+00:00

Also change the enum values to all-capital letters.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: Minor cleanups

2014-11-10T16:27:30+00:00

 . Update comments
 . drbd_set_{in,out_of}_sync(): Remove unused parameters
 . Move common code into adm_del_resource()
 . Redefine ERR_MINOR_EXISTS -> ERR_MINOR_OR_VOLUME_EXISTS

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: silence underflow warning in read_in_block()

2014-07-10T16:35:23+00:00

My static checker warns that "data_size" could be negative and underflow
the limit check.  The code looks suspicious but I don't know if it is a
real bug.

Signed-off-by: Dan Carpenter 
Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg