Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Pass the block_device and operation that we plan to use this bio for to
bio_alloc to optimize the assignment. NULL/0 can be passed, both for the
passthrough case on a raw request_queue and to temporarily avoid
refactoring some nasty code.
Also move the gfp_mask argument after the nr_vecs argument for a much
more logical calling convention matching what most of the kernel does.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fixes scripts/checkpatch.pl warning:
WARNING: Possible unnecessary 'out of memory' message
Remove it can help us save a bit of memory.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation to enable -Wimplicit-fallthrough for Clang, fix a couple
of warnings by explicitly adding a break statement instead of just
letting the code fall through to the next, and by adding a fallthrough
pseudo-keyword in places whre the code is intended to fall through.
Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fixes the following W=1 kernel build warning(s):
drivers/block/drbd/drbd_receiver.c:265: warning: Function parameter or member 'peer_device' not described in 'drbd_alloc_pages'
drivers/block/drbd/drbd_receiver.c:265: warning: Excess function parameter 'device' description in 'drbd_alloc_pages'
drivers/block/drbd/drbd_receiver.c:1362: warning: Function parameter or member 'connection' not described in 'drbd_may_finish_epoch'
drivers/block/drbd/drbd_receiver.c:1362: warning: Excess function parameter 'device' description in 'drbd_may_finish_epoch'
drivers/block/drbd/drbd_receiver.c:1451: warning: Function parameter or member 'resource' not described in 'drbd_bump_write_ordering'
drivers/block/drbd/drbd_receiver.c:1451: warning: Function parameter or member 'bdev' not described in 'drbd_bump_write_ordering'
drivers/block/drbd/drbd_receiver.c:1451: warning: Excess function parameter 'connection' description in 'drbd_bump_write_ordering'
drivers/block/drbd/drbd_receiver.c:1643: warning: Function parameter or member 'op' not described in 'drbd_submit_peer_request'
drivers/block/drbd/drbd_receiver.c:1643: warning: Function parameter or member 'op_flags' not described in 'drbd_submit_peer_request'
drivers/block/drbd/drbd_receiver.c:1643: warning: Function parameter or member 'fault_type' not described in 'drbd_submit_peer_request'
drivers/block/drbd/drbd_receiver.c:1643: warning: Excess function parameter 'rw' description in 'drbd_submit_peer_request'
drivers/block/drbd/drbd_receiver.c:3055: warning: Function parameter or member 'peer_device' not described in 'drbd_asb_recover_0p'
drivers/block/drbd/drbd_receiver.c:3138: warning: Function parameter or member 'peer_device' not described in 'drbd_asb_recover_1p'
drivers/block/drbd/drbd_receiver.c:3195: warning: Function parameter or member 'peer_device' not described in 'drbd_asb_recover_2p'
drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'peer_device' not described in 'receive_bitmap_plain'
drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'size' not described in 'receive_bitmap_plain'
drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'p' not described in 'receive_bitmap_plain'
drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'c' not described in 'receive_bitmap_plain'
drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'peer_device' not described in 'recv_bm_rle_bits'
drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'p' not described in 'recv_bm_rle_bits'
drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'c' not described in 'recv_bm_rle_bits'
drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'len' not described in 'recv_bm_rle_bits'
drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'peer_device' not described in 'decode_bitmap_c'
drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'p' not described in 'decode_bitmap_c'
drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'c' not described in 'decode_bitmap_c'
drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'len' not described in 'decode_bitmap_c'
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-6-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use struct block_device to lookup partitions on a disk. This removes
all usage of struct hd_struct from the I/O path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: Chao Yu <yuchao0@huawei.com> [f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allocate hd_struct together with struct block_device to pre-load
the lifetime rule changes in preparation of merging the two structures.
Note that part0 was previously embedded into struct gendisk, but is
a separate allocation now, and already points to the block_device instead
of the hd_struct. The lifetime of struct gendisk is still controlled by
the struct device embedded in the part0 hd_struct.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
DRBD keeps a block device open just to get and set the capacity from
it. Switch to primarily using the disk capacity as intended by the
block layer, and sync it to the bdev using revalidate_disk_size.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bd_disk is set on all block devices, including those for partitions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull sched/fifo updates from Ingo Molnar:
"This adds the sched_set_fifo*() encapsulation APIs to remove static
priority level knowledge from non-scheduler code.
The three APIs for non-scheduler code to set SCHED_FIFO are:
- sched_set_fifo()
- sched_set_fifo_low()
- sched_set_normal()
These are two FIFO priority levels: default (high), and a 'low'
priority level, plus sched_set_normal() to set the policy back to
non-SCHED_FIFO.
Since the changes affect a lot of non-scheduler code, we kept this in
a separate tree"
* tag 'sched-fifo-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
sched,tracing: Convert to sched_set_fifo()
sched: Remove sched_set_*() return value
sched: Remove sched_setscheduler*() EXPORTs
sched,psi: Convert to sched_set_fifo_low()
sched,rcutorture: Convert to sched_set_fifo_low()
sched,rcuperf: Convert to sched_set_fifo_low()
sched,locktorture: Convert to sched_set_fifo()
sched,irq: Convert to sched_set_fifo()
sched,watchdog: Convert to sched_set_fifo()
sched,serial: Convert to sched_set_fifo()
sched,powerclamp: Convert to sched_set_fifo()
sched,ion: Convert to sched_set_normal()
sched,powercap: Convert to sched_set_fifo*()
sched,spi: Convert to sched_set_fifo*()
sched,mmc: Convert to sched_set_fifo*()
sched,ivtv: Convert to sched_set_fifo*()
sched,drm/scheduler: Convert to sched_set_fifo*()
sched,msm: Convert to sched_set_fifo*()
sched,psci: Convert to sched_set_fifo*()
sched,drbd: Convert to sched_set_fifo*()
...
generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.
In this case, use fifo_low, because it only cares about being above
SCHED_NORMAL. Effectively changes prio from 2 to 1.
Cc: axboe@kernel.dk
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Add a helper to directly set the TCP_QUICKACK sockopt from kernel space
without going through a fake uaccess. Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a helper to directly set the TCP_NODELAY sockopt from kernel space
without going through a fake uaccess. Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a helper to directly set the TCP_CORK sockopt from kernel space
without going through a fake uaccess. Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
These macros are just used by a few files. Move them out of genhd.h,
which is included everywhere into a new standalone header.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Switching to struct_size for the allocation in fifo_alloc avoids
hard-coding the type of fifo_buffer.values in fifo_alloc. It also
provides overflow protection; to avoid pessimistic code being
generated by the compiler as a result, this patch also switches
fifo_size to unsigned, propagating the change as appropriate.
Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Stephen Kitt <steve@sk2.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Building with clang and KASAN, we get a warning about an overly large
stack frame on 32-bit architectures:
drivers/block/drbd/drbd_receiver.c:921:31: error: stack frame size of 1280 bytes in function 'conn_connect'
[-Werror,-Wframe-larger-than=]
We already allocate other data dynamically in this function, so
just do the same for the shash descriptor, which makes up most of
this memory.
Link: https://lore.kernel.org/lkml/20190617132440.2721536-1-arnd@arndb.de/
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Roland Kammerer <roland.kammerer@linbit.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Based on 1 normalized pattern(s):
is free software you can redistribute it and or modify it under the
terms of the gnu general public license as published by the free
software foundation either version 2 or at your option any later
version [drbd] is distributed in the hope that it will be useful but
without any warranty without even the implied warranty of
merchantability or fitness for a particular purpose see the gnu
general public license for more details you should have received a
copy of the gnu general public license along with [drbd] see the
file copying if not write to the free software foundation 675 mass
ave cambridge ma 02139 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 16 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520075212.050796421@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull Wimplicit-fallthrough updates from Gustavo A. R. Silva:
"Mark switch cases where we are expecting to fall through.
This is part of the ongoing efforts to enable -Wimplicit-fallthrough.
Most of them have been baking in linux-next for a whole development
cycle. And with Stephen Rothwell's help, we've had linux-next
nag-emails going out for newly introduced code that triggers
-Wimplicit-fallthrough to avoid gaining more of these cases while we
work to remove the ones that are already present.
We are getting close to completing this work. Currently, there are
only 32 of 2311 of these cases left to be addressed in linux-next. I'm
auditing every case; I take a look into the code and analyze it in
order to determine if I'm dealing with an actual bug or a false
positive, as explained here:
https://lore.kernel.org/lkml/c2fad584-1705-a5f2-d63c-824e9b96cf50@embeddedor.com/
While working on this, I've found and fixed the several missing
break/return bugs, some of them introduced more than 5 years ago.
Once this work is finished, we'll be able to universally enable
"-Wimplicit-fallthrough" to avoid any of these kinds of bugs from
entering the kernel again"
* tag 'Wimplicit-fallthrough-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (27 commits)
memstick: mark expected switch fall-throughs
drm/nouveau/nvkm: mark expected switch fall-throughs
NFC: st21nfca: Fix fall-through warnings
NFC: pn533: mark expected switch fall-throughs
block: Mark expected switch fall-throughs
ASN.1: mark expected switch fall-through
lib/cmdline.c: mark expected switch fall-throughs
lib: zstd: Mark expected switch fall-throughs
scsi: sym53c8xx_2: sym_nvram: Mark expected switch fall-through
scsi: sym53c8xx_2: sym_hipd: mark expected switch fall-throughs
scsi: ppa: mark expected switch fall-through
scsi: osst: mark expected switch fall-throughs
scsi: lpfc: lpfc_scsi: Mark expected switch fall-throughs
scsi: lpfc: lpfc_nvme: Mark expected switch fall-through
scsi: lpfc: lpfc_nportdisc: Mark expected switch fall-through
scsi: lpfc: lpfc_hbadisc: Mark expected switch fall-throughs
scsi: lpfc: lpfc_els: Mark expected switch fall-throughs
scsi: lpfc: lpfc_ct: Mark expected switch fall-throughs
scsi: imm: mark expected switch fall-throughs
scsi: csiostor: csio_wr: mark expected switch fall-through
...
Pull printk updates from Petr Mladek:
- Allow state reset of printk_once() calls.
- Prevent crashes when dereferencing invalid pointers in vsprintf().
Only the first byte is checked for simplicity.
- Make vsprintf warnings consistent and inlined.
- Treewide conversion of obsolete %pf, %pF to %ps, %pF printf
modifiers.
- Some clean up of vsprintf and test_printf code.
* tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
lib/vsprintf: Make function pointer_string static
vsprintf: Limit the length of inlined error messages
vsprintf: Avoid confusion between invalid address and value
vsprintf: Prevent crash when dereferencing invalid pointers
vsprintf: Consolidate handling of unknown pointer specifiers
vsprintf: Factor out %pO handler as kobject_string()
vsprintf: Factor out %pV handler as va_format()
vsprintf: Factor out %p[iI] handler as ip_addr_string()
vsprintf: Do not check address of well-known strings
vsprintf: Consistent %pK handling for kptr_restrict == 0
vsprintf: Shuffle restricted_pointer()
printk: Tie printk_once / printk_deferred_once into .data.once for reset
treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively
lib/test_printf: Switch to bitmap_zalloc()
The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.
With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP. These would all need to be fixed if any shash algorithm
actually started sleeping. For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API. However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.
Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk. It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.
Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
This patch fixes the following warnings:
drivers/block/drbd/drbd_int.h:1774:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/block/drbd/drbd_int.h:1774:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/block/drbd/drbd_int.h:1774:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/block/drbd/drbd_int.h:1774:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/block/drbd/drbd_int.h:1774:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/block/drbd/drbd_receiver.c:3093:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/block/drbd/drbd_receiver.c:3120:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/block/drbd/drbd_req.c:856:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
Warning level 3 was used: -Wimplicit-fallthrough=3
This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Roland Kammerer <roland.kammerer@linbit.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Pull more block updates from Jens Axboe:
- Dead code removal for loop/sunvdc (Chengguang)
- Mark BIDI support for bsg as deprecated, logging a single dmesg
warning if anyone is actually using it (Christoph)
- blkcg cleanup, killing a dead function and making the tryget_closest
variant easier to read (Dennis)
- Floppy fixes, one fixing a regression in swim3 (Finn)
- lightnvm use-after-free fix (Gustavo)
- gdrom leak fix (Wenwen)
- a set of drbd updates (Lars, Luc, Nathan, Roland)
* tag 'for-4.21/block-20190102' of git://git.kernel.dk/linux-block: (28 commits)
block/swim3: Fix regression on PowerBook G3
block/swim3: Fix -EBUSY error when re-opening device after unmount
block/swim3: Remove dead return statement
block/amiflop: Don't log error message on invalid ioctl
gdrom: fix a memory leak bug
lightnvm: pblk: fix use-after-free bug
block: sunvdc: remove redundant code
block: loop: remove redundant code
bsg: deprecate BIDI support in bsg
blkcg: remove unused __blkg_release_rcu()
blkcg: clean up blkg_tryget_closest()
drbd: Change drbd_request_detach_interruptible's return type to int
drbd: Avoid Clang warning about pointless switch statment
drbd: introduce P_ZEROES (REQ_OP_WRITE_ZEROES on the "wire")
drbd: skip spurious timeout (ping-timeo) when failing promote
drbd: don't retry connection if peers do not agree on "authentication" settings
drbd: fix print_st_err()'s prototype to match the definition
drbd: avoid spurious self-outdating with concurrent disconnect / down
drbd: do not block when adjusting "disk-options" while IO is frozen
drbd: fix comment typos
...
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.htmlhttps://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 <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
emma: "Unexpected data packet AuthChallenge (0x0010)"
ava: "expected AuthChallenge packet, received: ReportProtocol (0x000b)"
"Authentication of peer failed, trying again."
Pattern repeats.
There is no point in retrying the handshake,
if we expect to receive an AuthChallenge,
but the peer is not even configured to expect or use a shared secret.
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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 <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we would reject a new handshake, if the peer had attached first,
and then connected, we should force disconnect if the peer first connects,
and only then attaches.
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
