BMC/Intel-BMC/linux.git/drivers/block/drbd/drbd_nl.c, branch dev-5.0

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: skip spurious timeout (ping-timeo) when failing promote

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

If you try to promote a Secondary while connected to a Primary and allow-two-primaries is NOT set, we will wait for "ping-timeout" to give this node a chance to detect a dead primary, in case the cluster manager noticed faster than we did. But if we then are *still* connected to a Primary, we fail (after an additional timeout of ping-timout). This change skips the spurious second timeout. Most people won't notice really, since "ping-timeout" by default is half a second. But in some installations, ping-timeout may be 10 or 20 seconds or more, and spuriously delaying the error return becomes annoying. Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: avoid spurious self-outdating with concurrent disconnect / down

2018-12-20T16:51:30+00:00

If peers are "simultaneously" told to disconnect from each other, either explicitly, or implicitly by taking down the resource, with bad timing, one side may see its disconnect "fail" with a result of "state change failed by peer", and interpret this as "please oudate yourself". Try to catch this by checking for current connection status, and possibly retry as local-only state change instead. Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: do not block when adjusting "disk-options" while IO is frozen

2018-12-20T16:51:30+00:00

"suspending" IO is overloaded. It can mean "do not allow new requests" (obviously), but it also may mean "must not complete pending IO", for example while the fencing handlers do their arbitration. When adjusting disk options, we suspend io (disallow new requests), then wait for the activity-log to become unused (drain all IO completions), and possibly replace it with a new activity log of different size. If the other "suspend IO" aspect is active, pending IO completions won't happen, and we would block forever (unkillable drbdsetup process). Fix this by skipping the activity log adjustment if the "al-extents" setting did not change. Also, in case it did change, fail early without blocking if it looks like we would block forever. Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: reject attach of unsuitable uuids even if connected

2018-12-20T16:51:30+00:00

Multiple failure scenario: a) all good Connected Primary/Secondary UpToDate/UpToDate b) lose disk on Primary, Connected Primary/Secondary Diskless/UpToDate c) continue to write to the device, changes only make it to the Secondary storage. d) lose disk on Secondary, Connected Primary/Secondary Diskless/Diskless e) now try to re-attach on Primary This would have succeeded before, even though that is clearly the wrong data set to attach to (missing the modifications from c). Because we only compared our "effective" and the "to-be-attached" data generation uuid tags if (device->state.conn < C_CONNECTED). Fix: change that constraint to (device->state.pdsk != D_UP_TO_DATE) compare the uuids, and reject the attach. This patch also tries to improve the reverse scenario: first lose Secondary, then Primary disk, then try to attach the disk on Secondary. Before this patch, the attach on the Secondary succeeds, but since commit drbd: disconnect, if the wrong UUIDs are attached on a connected peer the Primary will notice unsuitable data, and drop the connection hard. Though unfortunately at a point in time during the handshake where we cannot easily abort the attach on the peer without more refactoring of the handshake. We now reject any attach to "unsuitable" uuids, as long as we can see a Primary role, unless we already have access to "good" data. Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: fix confusing error message during attach

2018-12-20T16:51:30+00:00

If we attach a (consistent) backing device, which knows about a last-agreed effective size, and that effective size is *larger* than the currently requested size, we refused to attach with ERR_DISK_TOO_SMALL Failure: (111) Low.dev. smaller than requested DRBD-dev. size. which is confusing to say the least. This patch changes the error code in that case to ERR_IMPLICIT_SHRINK Failure: (170) Implicit device shrinking not allowed. See kernel log. additional info from kernel: To-be-attached device has last effective > current size, and is consistent (9999 > 7777 sectors). Refusing to attach. It also allows to attach with an explicit size. Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: centralize printk reporting of new size into drbd_set_my_capacity()

2018-12-20T16:51:29+00:00

Previously, some implicit resizes that happend during handshake have not been reported as prominently as explicit resize. Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: Convert from ahash to shash

2018-09-06T21:12:24+00:00

In preparing to remove all stack VLA usage from the kernel[1], this removes the discouraged use of AHASH_REQUEST_ON_STACK in favor of the smaller SHASH_DESC_ON_STACK by converting from ahash-wrapped-shash to direct shash. By removing a layer of indirection this both improves performance and reduces stack usage. The stack allocation will be made a fixed size in a later patch to the crypto subsystem. The bulk of the lines in this change are simple s/ahash/shash/, but the main logic differences are in drbd_csum_ee() and drbd_csum_bio(), which externalizes the page walking with k(un)map_atomic() instead of using scattergather. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Acked-by: Lars Ellenberg Signed-off-by: Kees Cook Signed-off-by: Jens Axboe

block: Use blk_queue_flag_() in drivers instead of queue_flag_()

2018-03-08T21:13:48+00:00

This patch has been generated as follows: for verb in set_unlocked clear_unlocked set clear; do replace-in-files queue_flag_${verb} blk_queue_flag_${verb%_unlocked} \ $(git grep -lw queue_flag_${verb} drivers block/bsg*) done Except for protecting all queue flag changes with the queue lock this patch does not change any functionality. Cc: Mike Snitzer Cc: Shaohua Li Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Ming Lei Signed-off-by: Bart Van Assche Reviewed-by: Martin K. Petersen Reviewed-by: Johannes Thumshirn Acked-by: Martin K. Petersen Signed-off-by: Jens Axboe

drbd: rename "usermode_helper" to "drbd_usermode_helper"

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

Nothing like having a very generic global variable in a tiny driver subsystem to make a mess of the global namespace... Note, there are many other "generic" named global variables in the drbd subsystem, someone should fix those up one day before they hit a linking error. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

BMC/Intel-BMC/linux.git/drivers/block/drbd/drbd_nl.c, branch dev-5.0

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

drbd: skip spurious timeout (ping-timeo) when failing promote

drbd: avoid spurious self-outdating with concurrent disconnect / down

drbd: do not block when adjusting "disk-options" while IO is frozen

drbd: reject attach of unsuitable uuids even if connected

drbd: fix confusing error message during attach

drbd: centralize printk reporting of new size into drbd_set_my_capacity()

drbd: Convert from ahash to shash

block: Use blk_queue_flag_*() in drivers instead of queue_flag_*()

drbd: rename "usermode_helper" to "drbd_usermode_helper"

block: Use blk_queue_flag_() in drivers instead of queue_flag_()