fs: dlm: constify receive buffer

The dlm receive buffer should be never manipulated as DLM is the last
instance of parsing layer. This patch constify the whole receive buffer
so we are sure it never

fs: dlm: constify receive buffer

The dlm receive buffer should be never manipulated as DLM is the last
instance of parsing layer. This patch constify the whole receive buffer
so we are sure it never gets manipulated when it's being parsed.

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

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193

Based on 1 normalized pattern(s):

this copyrighted material is made available to anyone wishing to use
modify copy or redistri

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193

Based on 1 normalized pattern(s):

this copyrighted material is made available to anyone wishing to use
modify copy or redistribute it subject to the terms and conditions
of the gnu general public license v 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 45 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Richard Fontana <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Reviewed-by: Steve Winslow <[email protected]>
Reviewed-by: Alexios Zavras <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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dlm: use proper C for dlm/requestqueue stuff (and fix alignment bug)

a) don't cast the pointer to dlm_header *, we use it as dlm_message *
anyway.
b) we copy the message into a queue element, the

dlm: use proper C for dlm/requestqueue stuff (and fix alignment bug)

a) don't cast the pointer to dlm_header *, we use it as dlm_message *
anyway.
b) we copy the message into a queue element, then pass the pointer to
copy to dlm_receive_message_saved(); declare it properly to make sure
that we have the right alignment.

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

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[DLM] block dlm_recv in recovery transition

Introduce a per-lockspace rwsem that's held in read mode by dlm_recv
threads while working in the dlm. This allows dlm_recv activity to be
suspended when

[DLM] block dlm_recv in recovery transition

Introduce a per-lockspace rwsem that's held in read mode by dlm_recv
threads while working in the dlm. This allows dlm_recv activity to be
suspended when the lockspace transitions to, from and between recovery
cycles.

The specific bug prompting this change is one where an in-progress
recovery cycle is aborted by a new recovery cycle. While dlm_recv was
processing a recovery message, the recovery cycle was aborted and
dlm_recoverd began cleaning up. dlm_recv decremented recover_locks_count
on an rsb after dlm_recoverd had reset it to zero. This is fixed by
suspending dlm_recv (taking write lock on the rwsem) before aborting the
current recovery.

The transitions to/from normal and recovery modes are simplified by using
this new ability to block dlm_recv. The switch from normal to recovery
mode means dlm_recv goes from processing locking messages, to saving them
for later, and vice versa. Races are avoided by blocking dlm_recv when
setting the flag that switches between modes.

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

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[DLM] fix requestqueue race

Red Hat BZ 211914

There's a race between dlm_recoverd (1) enabling locking and (2) clearing
out the requestqueue, and dlm_recvd (1) checking if locking is enabled and
(2

[DLM] fix requestqueue race

Red Hat BZ 211914

There's a race between dlm_recoverd (1) enabling locking and (2) clearing
out the requestqueue, and dlm_recvd (1) checking if locking is enabled and
(2) adding a message to the requestqueue. An order of recoverd(1),
recvd(1), recvd(2), recoverd(2) will result in a message being left on the
requestqueue. The fix is to have dlm_recvd check if dlm_recoverd has
enabled locking after taking the mutex for the requestqueue and if it has
processing the message instead of queueing it.

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

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[DLM] The core of the DLM for GFS2/CLVM

This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalon

[DLM] The core of the DLM for GFS2/CLVM

This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.

It implements VAX-style locking modes.

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

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