kernel.git/fs/dlm/lock.h, branch linux-6.10.y

dlm: drop dlm_scand kthread and use timers

2024-04-16T19:40:27Z

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 Signed-off-by: David Teigland

dlm: do not use ref counts for rsb in the toss state

2024-04-16T19:34:39Z

In the past we had problems when an rsb had a reference counter greater than one while in the toss state. An rsb in the toss state is not actively used for locking, and should not have any other references apart from the single ref keeping it on the rsb hash. Shift to freeing rsb's directly rather than using kref_put to free them, since the ref counting is not meant to be used in this state. Add warnings if ref counting is seen while an rsb is in the toss state. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: switch to use rhashtable for rsbs

2024-04-16T19:34:39Z

Replace our own hash table with the more advanced rhashtable for keeping rsb structs. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: use spin_lock_bh for message processing

2024-04-09T16:45:23Z

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 Signed-off-by: David Teigland

dlm: convert res_lock to spinlock

2024-04-09T16:44:49Z

Convert the rsb struct res_lock from a mutex to a spinlock in preparation for processing messages in softirq context. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: drop mutex use in waiters recovery

2024-04-09T16:44:49Z

The waiters_mutex no longer needs to be used in the waiters recovery functions dlm_recover_waiters_pre() and dlm_recover_waiters_pre(). During recovery, ordinary locking operations are paused, and the recovery thread is the only context accessing the waiters list, so the lock is not needed. Access to the waiters list from debugfs functions is avoided by taking the top level recovery lock in the debugfs dump function. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: move rsb root_list to ls_recover() stack

2024-04-09T16:44:49Z

Move the rsb root_list from the lockspace to a stack variable since it is now only used by the ls_recover() function. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: constify receive buffer

2023-08-10T15:33:03Z

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 Signed-off-by: David Teigland

fs: dlm: drop rxbuf manipulation in dlm_recover_master_copy

2023-08-10T15:33:03Z

Currently dlm_recover_master_copy() manipulates the receive buffer of an rcom lock message and modifies it on the fly so a later memcpy() to a new rcom message with the same message has those new values. This patch avoids manipulating the received rcom message by store the values for the new rcom message in paremter assigned with call by reference. Later when dlm_send_rcom_lock() constructs a new message and memcpy() the receive buffer those values will be set on the new constructed message. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: get recovery sequence number as parameter

2023-08-10T15:33:03Z

This patch removes a read of the ls->ls_recover_seq uint64_t number in _create_rcom(). If the ls->ls_recover_seq is readed the ls_recover_lock need to held. However this number was always readed before when any rcom message is received and it's not necessary to read it again from a per lockspace variable to use it for the replying message. This patch will pass the sequence number as parameter so another read of ls->ls_recover_seq and holding the ls->ls_recover_lock is not required. Signed-off-by: Alexander Aring Signed-off-by: David Teigland