dlm: prevent NPD when writing a positive value to event_done

do_uevent returns the value written to event_done. In case it is a
positive value, new_lockspace would undo all the work, and lockspace
w

dlm: prevent NPD when writing a positive value to event_done

do_uevent returns the value written to event_done. In case it is a
positive value, new_lockspace would undo all the work, and lockspace
would not be set. __dlm_new_lockspace, however, would treat that
positive value as a success due to commit 8511a2728ab8 ("dlm: fix use
count with multiple joins").

Down the line, device_create_lockspace would pass that NULL lockspace to
dlm_find_lockspace_local, leading to a NULL pointer dereference.

Treating such positive values as successes prevents the problem. Given
this has been broken for so long, this is unlikely to break userspace
expectations.

Fixes: 8511a2728ab8 ("dlm: fix use count with multiple joins")
Signed-off-by: Thadeu Lima de Souza Cascardo <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: async freeing of lockspace resources

This patch handles freeing of lockspace resources asynchronously besides
the release_lockspace() context. The release_lockspace() context is
sometimes calle

dlm: async freeing of lockspace resources

This patch handles freeing of lockspace resources asynchronously besides
the release_lockspace() context. The release_lockspace() context is
sometimes called in a time critical context, e.g. umount syscall. Most
every user space init system will timeout if it takes too long. To
reduce the potential waiting time we deregister in release_lockspace()
the lockspace from the DLM subsystem and do the actual releasing of
lockspace resource in a worker of a workqueue following recommendation
of:

https://lore.kernel.org/all/[email protected]/T/#u

as flushing of system workqueues are not allowed. The most time to
release the DLM resources are spent to release the data structures
"ls->ls_lkbxa" and "ls->ls_rsbtbl" as they iterate over each entries and
those data structures can contain millions of entries. This patch handles
for now only freeing of those data structures as those operations are
the most reason why release_lockspace() blocking of being returned.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: drop kobject release callback handling

This patch removes the releasing of the "struct dlm ls" resource out of
the kobject handling. Instead we run kfree() after kobject_put() of the
lockspace

dlm: drop kobject release callback handling

This patch removes the releasing of the "struct dlm ls" resource out of
the kobject handling. Instead we run kfree() after kobject_put() of the
lockspace kobject structure that should always being the last put call.
This prepares to split the releasing of all lockspace resources
asynchronously in the background and just deregister everything in
release_lockspace().

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: remove DLM_LSFL_SOFTIRQ from exflags

The DLM rcom handling has a check that all exflags are the same for the
whole lockspace membership nodes. There are some flags that requires
such handling,

dlm: remove DLM_LSFL_SOFTIRQ from exflags

The DLM rcom handling has a check that all exflags are the same for the
whole lockspace membership nodes. There are some flags that requires
such handling, however DLM_LSFL_SOFTIRQ does not require this handling
and it should be backwards compatibility with other lockspaces that does
not set this flag.

Fixes: f328a26eeb53 ("dlm: introduce DLM_LSFL_SOFTIRQ_SAFE")
Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: implement LSFL_SOFTIRQ_SAFE

When a lockspace user allows it, run callback functions directly from
softirq context, instead of queueing callbacks to be run from the
dlm_callback workqueue contex

dlm: implement LSFL_SOFTIRQ_SAFE

When a lockspace user allows it, run callback functions directly from
softirq context, instead of queueing callbacks to be run from the
dlm_callback workqueue context.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: introduce DLM_LSFL_SOFTIRQ_SAFE

Introduce a new external lockspace flag DLM_LSFL_SOFTIRQ_SAFE. A
lockspace user will set this flag if it can handle dlm running the
callback functions from soft

dlm: introduce DLM_LSFL_SOFTIRQ_SAFE

Introduce a new external lockspace flag DLM_LSFL_SOFTIRQ_SAFE. A
lockspace user will set this flag if it can handle dlm running the
callback functions from softirq context. When not set, dlm will
continue to run callback functions from the dlm_callback workqueue.
The new lockspace flag cannot be used for user space lockspaces, so
a uapi placeholder definition is used for the new flag value.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: use LSFL_FS to check for kernel lockspace

The existing external lockspace flag DLM_LSFL_FS is now also
saved as an internal flag LSFL_FS, so it can be checked from
other code locations which wa

dlm: use LSFL_FS to check for kernel lockspace

The existing external lockspace flag DLM_LSFL_FS is now also
saved as an internal flag LSFL_FS, so it can be checked from
other code locations which want to know if a lockspace is
used from the kernel or user space.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: change list and timer names

The old terminology of "toss" and "keep" is no longer an
accurate description of the rsb states and lists, so change
the names to "inactive" and "active". The old n

dlm: change list and timer names

The old terminology of "toss" and "keep" is no longer an
accurate description of the rsb states and lists, so change
the names to "inactive" and "active". The old names had
also been copied into the scanning code, which is changed
back to use the "scan" name.

- "active" rsb structs have lkb's attached, and are ref counted.
- "inactive" rsb structs have no lkb's attached, are not ref counted.
- "scan" list is for rsb's that can be freed after a timeout period.
- "slow" lists are for infrequent iterations through active or
inactive rsb structs.
- inactive rsb structs that are directory records will not be put
on the scan list, since they are not freed based on timeouts.
- inactive rsb structs that are not directory records will be
put on the scan list to be freed, since they are not longer needed.

Signed-off-by: David Teigland <[email protected]>

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dlm: move recover idr to xarray datastructure

According to kdoc idr is deprecated and xarrays should be used nowadays.
This patch is moving the recover idr implementation to xarray
datastructure.

S

dlm: move recover idr to xarray datastructure

According to kdoc idr is deprecated and xarrays should be used nowadays.
This patch is moving the recover idr implementation to xarray
datastructure.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: move lkb idr to xarray datastructure

According to kernel doc idr is deprecated and xarrays should be used
nowadays. This patch is moving the lkb idr implementation to xarrays.

Signed-off-by: A

dlm: move lkb idr to xarray datastructure

According to kernel doc idr is deprecated and xarrays should be used
nowadays. This patch is moving the lkb idr implementation to xarrays.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: drop own rsb pre allocation mechanism

This patch drops the own written rsb pre allocation mechanism as this is
already done by using kmem caches, we don't need another layer on top of
that to r

dlm: drop own rsb pre allocation mechanism

This patch drops the own written rsb pre allocation mechanism as this is
already done by using kmem caches, we don't need another layer on top of
that to running some pre allocation scheme.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: remove ls_local_handle from struct dlm_ls

This patch removes ls_local_handle from struct dlm_ls as it stores the
ls pointer of the top level structure itesef and this isn't necessary.
There is

dlm: remove ls_local_handle from struct dlm_ls

This patch removes ls_local_handle from struct dlm_ls as it stores the
ls pointer of the top level structure itesef and this isn't necessary.
There is a lookup functionality to lookup the lockspace in
dlm_find_lockspace_local() but the given input parameter is the pointer
already. This might be more safe to lookup a lockspace but given a wrong
lockspace pointer is a bug in the code and we save the additional lookup
here. The dlm_ls structure can be still hidden by using dlm_lockspace_t
handle pointer.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: remove scand leftovers

This patch removes some leftover related code from dlm_scand that was
dropped in commit b1f2381c1a8d ("dlm: drop dlm_scand kthread and use
timers").

Signed-off-by: Alexa

dlm: remove scand leftovers

This patch removes some leftover related code from dlm_scand that was
dropped in commit b1f2381c1a8d ("dlm: drop dlm_scand kthread and use
timers").

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: return -ENOMEM if ls_recover_buf fails

This patch fixes to return -ENOMEM in case of an allocation failure that
was forgotten to change in commit 6c648035cbe7 ("dlm: switch to use
rhashtable fo

dlm: return -ENOMEM if ls_recover_buf fails

This patch fixes to return -ENOMEM in case of an allocation failure that
was forgotten to change in commit 6c648035cbe7 ("dlm: switch to use
rhashtable for rsbs").

Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]/
Fixes: 6c648035cbe7 ("dlm: switch to use rhashtable for rsbs")
Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: fix sleep in atomic context

This patch changes the orphans mutex to a spinlock since commit
c288745f1d4a ("dlm: avoid blocking receive at the end of recovery") is
using a rwlock_t to lock the D

dlm: fix sleep in atomic context

This patch changes the orphans mutex to a spinlock since commit
c288745f1d4a ("dlm: avoid blocking receive at the end of recovery") is
using a rwlock_t to lock the DLM message receive path and do_purge() can
be called while this lock is held that forbids to sleep.

We need to use spin_lock_bh() because also a user context that calls
dlm_user_purge() can call do_purge() and since commit 92d59adfaf71
("dlm: do message processing in softirq context") the DLM message
receive path is done under softirq context.

Fixes: c288745f1d4a ("dlm: avoid blocking receive at the end of recovery")
Reported-by: Dan Carpenter <[email protected]>
Closes: https://lore.kernel.org/gfs2/[email protected]/
Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: use rwlock for lkbidr

Convert the lock for lkbidr to an rwlock. Most idr lookups will use
the read lock.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <te

dlm: use rwlock for lkbidr

Convert the lock for lkbidr to an rwlock. Most idr lookups will use
the read lock.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: use rwlock for rsb hash table

The conversion to rhashtable introduced a hash table lock per lockspace,
in place of per bucket locks. To make this more scalable, switch to
using a rwlock for ha

dlm: use rwlock for rsb hash table

The conversion to rhashtable introduced a hash table lock per lockspace,
in place of per bucket locks. To make this more scalable, switch to
using a rwlock for hash table access. The common case fast path uses
it as a read lock.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: drop dlm_scand kthread and use timers

Currently the scand kthread acts like a garbage collection for expired
rsbs on toss list, to clean them up after a certain timeout. It triggers
every coupl

dlm: drop dlm_scand kthread and use timers

Currently the scand kthread acts like a garbage collection for expired
rsbs on toss list, to clean them up after a certain timeout. It triggers
every couple of seconds and iterates over the toss list while holding
ls_rsbtbl_lock for the whole hash bucket iteration.

To reduce the amount of time holding ls_rsbtbl_lock, we now handle the
disposal of expired rsbs using a per-lockspace timer that expires for the
earliest tossed rsb on the lockspace toss queue. This toss queue is
ordered according to the rsb res_toss_time with the earliest tossed rsb
as the first entry. The toss timer will only trylock() necessary locks,
since it is low priority garbage collection, and will rearm the timer
if trylock() fails. If the timer function does not find any expired
rsb's, it rearms the timer with the next earliest expired rsb.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: switch to use rhashtable for rsbs

Replace our own hash table with the more advanced rhashtable
for keeping rsb structs.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: Davi

dlm: switch to use rhashtable for rsbs

Replace our own hash table with the more advanced rhashtable
for keeping rsb structs.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: add rsb lists for iteration

To prepare for using rhashtable, add two rsb lists for iterating
through rsb's in two uncommon cases where this is necesssary:
- when dumping rsb state from debugfs,

dlm: add rsb lists for iteration

To prepare for using rhashtable, add two rsb lists for iterating
through rsb's in two uncommon cases where this is necesssary:
- when dumping rsb state from debugfs, now using seq_list.
- when looking at all rsb's during recovery.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: merge toss and keep hash table lists into one list

There are several places where lock processing can perform two hash table
lookups, first in the "keep" list, and if not found, in the "toss" l

dlm: merge toss and keep hash table lists into one list

There are several places where lock processing can perform two hash table
lookups, first in the "keep" list, and if not found, in the "toss" list.
This patch introduces a new rsb state flag "RSB_TOSS" to represent the
difference between the state of being on keep vs toss list, so that the
two lists can be combined. This avoids cases of two lookups.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: change to single hashtable lock

Prepare to replace our own hash table with rhashtable by replacing
the per-bucket locks in our own hash table with a single lock.

Signed-off-by: Alexander Aring

dlm: change to single hashtable lock

Prepare to replace our own hash table with rhashtable by replacing
the per-bucket locks in our own hash table with a single lock.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: increment ls_count for dlm_scand

Increment the ls_count value while dlm_scand is processing a
lockspace so that release_lockspace()/remove_lockspace() will
wait for dlm_scand to finish.

Signed

dlm: increment ls_count for dlm_scand

Increment the ls_count value while dlm_scand is processing a
lockspace so that release_lockspace()/remove_lockspace() will
wait for dlm_scand to finish.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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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 <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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dlm: convert ls_recv_active from rw_semaphore to rwlock

Convert ls_recv_active rw_semaphore to an rwlock to avoid
sleeping, in preparation for softirq message processing.

Signed-off-by: Alexander A

dlm: convert ls_recv_active from rw_semaphore to rwlock

Convert ls_recv_active rw_semaphore to an rwlock to avoid
sleeping, in preparation for softirq message processing.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David Teigland <[email protected]>

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