dlm: use spin_lock_bh for message processing

Use spin_lock_bh for all spinlocks involved in message processing,
in preparation for softirq message processing. DLM lock requests
from user space invo

dlm: use spin_lock_bh for message processing

Use spin_lock_bh for all spinlocks involved in message processing,
in preparation for softirq message processing. DLM lock requests
from user space involve dlm processing in user context, in addition
to the standard kernel context, necessitating bh variants.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: remove callback reference counting

Get rid of the unnecessary refcounting on callback structs.
Copy interesting callback info into the lkb struct rather
than maintaining pointers to callback st

dlm: remove callback reference counting

Get rid of the unnecessary refcounting on callback structs.
Copy interesting callback info into the lkb struct rather
than maintaining pointers to callback structs from the lkb.
This goes back to the way things were done prior to
commit 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks").

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: fix race between final callback and remove

This patch fixes the following issue:

node 1 is dir
node 2 is master
node 3 is other

1->2: unlock
2: put final lkb, rsb moved to toss
2->1: unlock_r

dlm: fix race between final callback and remove

This patch fixes the following issue:

node 1 is dir
node 2 is master
node 3 is other

1->2: unlock
2: put final lkb, rsb moved to toss
2->1: unlock_reply
1: queue lkb callback with EUNLOCK
2->1: remove
1: receive_remove ignored (rsb on keep because of queued lkb callback)
1: complete lkb callback, put_lkb, move rsb to toss
3->1: lookup
1->3: lookup_reply master=2
3->2: request
2->3: request_reply EBADR

In summary:
An unexpected lkb reference causes the rsb to remain on the wrong list.
The rsb being on the wrong list causes receive_remove to be ignored.
An ignored receive_remove causes inconsistent dir and master state.

This sequence requires an unusually long delay in delivering the unlock
callback, because the remove message from 2->1 usually happens after
some seconds. So, it's not known exactly how frequently this sequence
occurs in pratice. It's possible that the same end result could also
have another unknown cause.

The solution for this issue is to further separate callback state
from the lkb, so that an lkb reference (and from that, an rsb ref)
are not held while a callback remains queued. Then, within the
unlock_reply, the lkb will be freed and the rsb moved to the toss
list. So, the receive_remove will not be ignored.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: combine switch case fail and default statements

This patch combines the failure and default cases for enqueue and
dequeue a callback to the lkb callback queue that should end in both
cases as i

dlm: combine switch case fail and default statements

This patch combines the failure and default cases for enqueue and
dequeue a callback to the lkb callback queue that should end in both
cases as it should never happen.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: remove lkb from callback tracepoints

Stop using lkb structs in the callback tracepoints so that lkb
references are not needed. This prepares for separating lkb
structs from callbacks.

Signed-o

dlm: remove lkb from callback tracepoints

Stop using lkb structs in the callback tracepoints so that lkb
references are not needed. This prepares for separating lkb
structs from callbacks.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: fix user space lock decision to copy lvb

This patch fixes the copy lvb decision for user space lock requests.
Checking dlm_lvb_operations is done earlier, where granted/requested
lock modes are

dlm: fix user space lock decision to copy lvb

This patch fixes the copy lvb decision for user space lock requests.
Checking dlm_lvb_operations is done earlier, where granted/requested
lock modes are available to use in the matrix.

The decision had been moved to the wrong location, where granted mode
and requested mode where the same, which causes the dlm_lvb_operations
matix to produce the wrong copy decision. For PW or EX requests, the
caller could get invalid lvb data.

Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: fix user space lkb refcounting

This patch fixes to check on the right return value if it was the last
callback. The rv variable got overwritten by the return of
copy_result_to_user(). Fixing it

dlm: fix user space lkb refcounting

This patch fixes to check on the right return value if it was the last
callback. The rv variable got overwritten by the return of
copy_result_to_user(). Fixing it by introducing a second variable for
the return value and don't let rv being overwritten.

Cc: stable@vger.kernel.org
Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks")
Reported-by: Valentin Vidić <vvidic@valentin-vidic.from.hr>
Closes: https://lore.kernel.org/gfs2/Ze4qSvzGJDt5yxC3@valentin-vidic.from.hr
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: move dlm_purge_lkb_callbacks to user module

This patch moves the dlm_purge_lkb_callbacks() function from ast to user
dlm module as it is only a function being used by dlm user
implementatio

fs: dlm: move dlm_purge_lkb_callbacks to user module

This patch moves the dlm_purge_lkb_callbacks() function from ast to user
dlm module as it is only a function being used by dlm user
implementation. I got be hinted to hold specific locks regarding the
callback handling for dlm_purge_lkb_callbacks() but it was false
positive. It is confusing because ast dlm implementation uses a
different locking behaviour as user locks uses as DLM handles kernel and
user dlm locks differently. To avoid the confusing we move this function
to dlm user implementation.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: move internal flags to atomic ops

This patch will move the lkb_flags value to the recently introduced
lkb_iflags value. For lkb_iflags we use atomic bit operations because
some flags like D

fs: dlm: move internal flags to atomic ops

This patch will move the lkb_flags value to the recently introduced
lkb_iflags value. For lkb_iflags we use atomic bit operations because
some flags like DLM_IFL_CB_PENDING are used while non rsb lock is held
to avoid issues with other flag manipulations which might run at the
same time we switch to atomic bit operations. Snapshot the bit values to
an uint32_t value is only used for debugging/logging use cases and don't
need to be 100% correct.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: change dflags to use atomic bits

Currently manipulating lkb_dflags assumes to held the rsb lock assigned
to the lkb. This is held by dlm message processing after certain
time to lookup the

fs: dlm: change dflags to use atomic bits

Currently manipulating lkb_dflags assumes to held the rsb lock assigned
to the lkb. This is held by dlm message processing after certain
time to lookup the right rsb from the received lkb message id. For user
space locks flags, which is currently the only use case for lkb_dflags,
flags are also being set during dlm character device handling without
holding the rsb lock. To minimize the risk that bit operations are
getting corrupted we switch to atomic bit operations. This patch will
also introduce helpers to snapshot atomic bit values in an non atomic
way. There might be still issues with the flag handling e.g. running in
case of manipulating bit ops and snapshot them at the same time, but this
patch minimize them and will start to use atomic bit operations.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: store lkb distributed flags into own value

This patch stores lkb distributed flags value in an separate value
instead of sharing internal and distributed flags in lkb->lkb_flags value.
This

fs: dlm: store lkb distributed flags into own value

This patch stores lkb distributed flags value in an separate value
instead of sharing internal and distributed flags in lkb->lkb_flags value.
This has the advantage to not mask/write back flag values in
receive_flags() functionality. The dlm debug_fs does not provide the
distributed flags anymore, those can be added in future.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: remove deprecated code parts

This patch removes code parts which was declared deprecated by
commit 6b0afc0cc3e9 ("fs: dlm: don't use deprecated timeout features by
default"). This contains

fs: dlm: remove deprecated code parts

This patch removes code parts which was declared deprecated by
commit 6b0afc0cc3e9 ("fs: dlm: don't use deprecated timeout features by
default"). This contains the following dlm functionality:

- start a cancel of a dlm request did not complete after certain timeout:
The current way how dlm cancellation works and interfering with other
dlm requests triggered by the user can end in an overlapping and
returning in -EBUSY. The most user don't handle this case and are
unaware that DLM can return such errno in such situation. Due the
timeout the user are mostly unaware when this happens.
- start a netlink warning messages for user space if dlm requests did
not complete after certain timeout:
This feature was never being built in the only known dlm user space side.
As we are to remove the timeout cancellation feature we can directly
remove this feature as well.

There might be the possibility to bring the timeout cancellation feature
back. However the current way of handling the -EBUSY case which is only
a software limitation and not a hardware limitation should be changed.
We minimize the current code base in DLM cancellation feature to not have
to deal with those existing features while solving the DLM cancellation
feature in general.

UAPI define DLM_LSFL_TIMEWARN is commented as deprecated and reserved
value. We should avoid at first to give it a new meaning but let
possible users still compile by keeping this define. In far future we
can give this flag a new meaning. The same for the DLM_LKF_TIMEOUT lock
request flag.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: fix DLM_IFL_CB_PENDING gets overwritten

This patch introduce a new internal flag per lkb value to handle
internal flags which are handled not on wire. The current lkb internal
flags stored

fs: dlm: fix DLM_IFL_CB_PENDING gets overwritten

This patch introduce a new internal flag per lkb value to handle
internal flags which are handled not on wire. The current lkb internal
flags stored as lkb->lkb_flags are split in upper and lower bits, the
lower bits are used to share internal flags over wire for other cluster
wide lkb copies on other nodes.

In commit 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks")
we introduced a new internal flag for pending callbacks for the dlm
callback queue. This flag is protected by the lkb->lkb_cb_lock lock.
This patch overlooked that on dlm receive path and the mentioned upper
and lower bits, that dlm will read the flags, mask it and write it
back. As example receive_flags() in fs/dlm/lock.c. This flag
manipulation is not done atomically and is not protected by
lkb->lkb_cb_lock. This has unknown side effects of the current callback
handling.

In future we should move to set/clear/test bit functionality and avoid
read, mask and writing back flag values. In later patches we will move
the upper parts to the new introduced internal lkb flags which are not
shared between other cluster nodes to the new non shared internal flag
field to avoid similar issues.

Cc: stable@vger.kernel.org
Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks")
Reported-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: rename DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDING

This patch renames DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDING because
CB_PENDING is a proper name to describe this flag. This flag is set when

fs: dlm: rename DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDING

This patch renames DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDING because
CB_PENDING is a proper name to describe this flag. This flag is set when
callback enqueue will return DLM_ENQUEUE_CALLBACK_NEED_SCHED because the
callback worker need to be queued. The flag tells that callbacks are
currently pending to be called and will be unset if the callback work
for the specific lkb is done. The term need schedule is part of this
time but a proper name is to say that there are some callbacks pending
to being called.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: ast do WARN_ON_ONCE() on hotpath

This patch changes the ast hotpath functionality in very unlikely cases
that we do WARN_ON_ONCE() instead of WARN_ON() to not spamming the
console output if

fs: dlm: ast do WARN_ON_ONCE() on hotpath

This patch changes the ast hotpath functionality in very unlikely cases
that we do WARN_ON_ONCE() instead of WARN_ON() to not spamming the
console output if we run into states that it would occur over and over
again.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: use a non-static queue for callbacks

This patch will introducde a queue implementation for callbacks by using
the Linux lists. The current callback queue handling is implemented by a
static

fs: dlm: use a non-static queue for callbacks

This patch will introducde a queue implementation for callbacks by using
the Linux lists. The current callback queue handling is implemented by a
static limit of 6 entries, see DLM_CALLBACKS_SIZE. The sequence number
inside the callback structure was used to see if the entries inside the
static entry is valid or not. We don't need any sequence numbers anymore
with a dynamic datastructure with grows and shrinks during runtime to
offer such functionality.

We assume that every callback will be delivered to the DLM user if once
queued. Therefore the callback flag DLM_CB_SKIP was dropped and the
check for skipping bast was moved before worker handling and not skip
while the callback worker executes. This will reduce unnecessary queues
of the callback worker.

All last callback saves are pointers now and don't need to copied over.
There is a reference counter for callback structures which will care
about to free the callback structures at the right time if they are not
referenced anymore.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: use list_first_entry marco

Instead of using list_entry() this patch moves to using the
list_first_entry() macro.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David T

fs: dlm: use list_first_entry marco

Instead of using list_entry() this patch moves to using the
list_first_entry() macro.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: remove DLM_LSFL_FS from uapi

The DLM_LSFL_FS flag is set in lockspaces created directly
for a kernel user, as opposed to those lockspaces created
for user space applications. The user spac

fs: dlm: remove DLM_LSFL_FS from uapi

The DLM_LSFL_FS flag is set in lockspaces created directly
for a kernel user, as opposed to those lockspaces created
for user space applications. The user space libdlm allowed
this flag to be set for lockspaces created from user space,
but then used by a kernel user. No kernel user has ever
used this method, so remove the ability to do it.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: trace user space callbacks

This patch adds trace callbacks for user locks. Unfortenately user locks
are handled in a different way than kernel locks in some cases. User
locks never call the

fs: dlm: trace user space callbacks

This patch adds trace callbacks for user locks. Unfortenately user locks
are handled in a different way than kernel locks in some cases. User
locks never call the dlm_lock()/dlm_unlock() kernel API and use the next
step internal API of dlm. Adding those traces from user API callers
should make it possible for dlm trace system to see lock handling for
user locks as well.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: change ls_clear_proc_locks to spinlock

This patch changes the ls_clear_proc_locks to a spinlock because there
is no need to handle it as a mutex as there is no sleepable context when
ls_cle

fs: dlm: change ls_clear_proc_locks to spinlock

This patch changes the ls_clear_proc_locks to a spinlock because there
is no need to handle it as a mutex as there is no sleepable context when
ls_clear_proc_locks is held. This allows us to call those functionality
in non-sleepable contexts.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: don't use deprecated timeout features by default

This patch will disable use of deprecated timeout features if
CONFIG_DLM_DEPRECATED_API is not set. The deprecated features
will be removed

fs: dlm: don't use deprecated timeout features by default

This patch will disable use of deprecated timeout features if
CONFIG_DLM_DEPRECATED_API is not set. The deprecated features
will be removed in upcoming kernel release v6.2.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: add deprecation Kconfig and warnings for timeouts

This patch adds a CONFIG_DLM_DEPRECATED_API Kconfig option
that must be enabled to use two timeout-related features
that we intend to remov

fs: dlm: add deprecation Kconfig and warnings for timeouts

This patch adds a CONFIG_DLM_DEPRECATED_API Kconfig option
that must be enabled to use two timeout-related features
that we intend to remove in kernel v6.2. Warnings are
printed if either is enabled and used. Neither has ever
been used as far as we know.

. The DLM_LSFL_TIMEWARN lockspace creation flag will be
removed, along with the associated configfs entry for
setting the timeout. Setting the flag and configfs file
would cause dlm to track how long locks were waiting
for reply messages. After a timeout, a kernel message
would be logged, and a netlink message would be sent
to userspace. Recently, midcomms messages have been
added that produce much better logging about actual
problems with messages. No use has ever been found
for the netlink messages.

. The userspace libdlm API has allowed the DLM_LKF_TIMEOUT
flag with a timeout value to be set in lock requests.
The lock request would be cancelled after the timeout.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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fs: dlm: remove timeout from dlm_user_adopt_orphan

Remove the unused timeout parameter from dlm_user_adopt_orphan().

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigla

fs: dlm: remove timeout from dlm_user_adopt_orphan

Remove the unused timeout parameter from dlm_user_adopt_orphan().

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: remove __user conversion warnings

This patch avoids the following sparse warning:

fs/dlm/user.c:111:38: warning: incorrect type in assignment (different address spaces)
fs/dlm/user.c:111:38:

dlm: remove __user conversion warnings

This patch avoids the following sparse warning:

fs/dlm/user.c:111:38: warning: incorrect type in assignment (different address spaces)
fs/dlm/user.c:111:38: expected void [noderef] __user *castparam
fs/dlm/user.c:111:38: got void *
fs/dlm/user.c:112:37: warning: incorrect type in assignment (different address spaces)
fs/dlm/user.c:112:37: expected void [noderef] __user *castaddr
fs/dlm/user.c:112:37: got void *
fs/dlm/user.c:113:38: warning: incorrect type in assignment (different address spaces)
fs/dlm/user.c:113:38: expected void [noderef] __user *bastparam
fs/dlm/user.c:113:38: got void *
fs/dlm/user.c:114:37: warning: incorrect type in assignment (different address spaces)
fs/dlm/user.c:114:37: expected void [noderef] __user *bastaddr
fs/dlm/user.c:114:37: got void *
fs/dlm/user.c:115:33: warning: incorrect type in assignment (different address spaces)
fs/dlm/user.c:115:33: expected struct dlm_lksb [noderef] __user *lksb
fs/dlm/user.c:115:33: got void *
fs/dlm/user.c:130:39: warning: cast removes address space '__user' of expression
fs/dlm/user.c:131:40: warning: cast removes address space '__user' of expression
fs/dlm/user.c:132:36: warning: cast removes address space '__user' of expression

So far I see there is no direct handling of copying a pointer value to
another pointer value. The handling only copies the actual pointer
address to a scalar type or vice versa. This should be okay because it
never handles dereferencing anything of those addresses in the kernel
space. To get rid of those warnings we doing some different casting
which results in no warnings in sparse or compiler.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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dlm: user: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare

dlm: user: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David Teigland <teigland@redhat.com>

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