kernel/linux.git/fs/dlm/ast.c, branch linux-6.0.y

fs: dlm: fix race between test_bit() and queue_work()

2022-10-21T10:37:36+00:00

commit eef6ec9bf390e836a6c4029f3620fe49528aa1fe upstream. This patch fixes a race by using ls_cb_mutex around the bit operations and conditional code blocks for LSFL_CB_DELAY. The function dlm_callback_stop() expects to stop all callbacks and flush all currently queued onces. The set_bit() is not enough because there can still be queue_work() after the workqueue was flushed. To avoid queue_work() after set_bit(), surround both by ls_cb_mutex. Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Greg Kroah-Hartman

fs: dlm: remove additional dereference of lksb

2022-06-24T16:53:08+00:00

This patch removes a dereference of lksb of lkb when calling ast tracepoint. First it reduces additional overhead, even if traces are not active. Second we can deference it in TP_fast_assign from the existing lkb parameter. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: change ast and bast trace order

2022-06-24T16:53:06+00:00

This patch moves the trace calls for ast and bast to before the ast and bast callback functions are called rather than after. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: use list_empty() to check last iteration

2021-12-07T18:42:26+00:00

This patch will use list_empty(&ls->ls_cb_delay) to check for last list iteration. In case of a multiply count of MAX_CB_QUEUE and the list is empty we do a extra goto more which we can avoid by checking on list_empty(). Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: initial support for tracepoints

2021-11-02T19:39:20+00:00

This patch adds initial support for dlm tracepoints. It will introduce tracepoints to dlm main functionality dlm_lock()/dlm_unlock() and their complete ast() callback or blocking bast() callback. The lock/unlock functionality has a start and end tracepoint, this is because there exists a race in case if would have a tracepoint at the end position only the complete/blocking callbacks could occur before. To work with eBPF tracing and using their lookup hash functionality there could be problems that an entry was not inserted yet. However use the start functionality for hash insert and check again in end functionality if there was an dlm internal error so there is no ast callback. In further it might also that locks with local masters will occur those callbacks immediately so we must have such functionality. I did not make everything accessible yet, although it seems eBPF can be used to access a lot of internal datastructures if it's aware of the struct definitions of the running kernel instance. We still can change it, if you do eBPF experiments e.g. time measurements between lock and callback functionality you can simple use the local lkb_id field as hash value in combination with the lockspace id if you have multiple lockspaces. Otherwise you can simple use trace-cmd for some functionality, e.g. `trace-cmd record -e dlm` and `trace-cmd report` afterwards. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: make dlm_callback_resume quite

2021-11-02T19:39:20+00:00

This patch makes dlm_callback_resume info printout less noisy by accumulate all callback queues into one printout not in 25 times steps. It seems this printout became lately quite noisy in relationship with gfs2. Before: [241767.849302] dlm: bin: dlm_callback_resume 25 [241767.854846] dlm: bin: dlm_callback_resume 25 [241767.860373] dlm: bin: dlm_callback_resume 25 ... [241767.865920] dlm: bin: dlm_callback_resume 25 [241767.871352] dlm: bin: dlm_callback_resume 25 [241767.876733] dlm: bin: dlm_callback_resume 25 After the patch: [ 385.485728] dlm: gfs2: dlm_callback_resume 175 if zero it will not be printed out. Reported-by: Barry Marson Signed-off-by: Alexander Aring Signed-off-by: David Teigland

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

2019-05-30T18:29:21+00:00

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 Reviewed-by: Richard Fontana Reviewed-by: Allison Randal Reviewed-by: Steve Winslow Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528170027.342746075@linutronix.de Signed-off-by: Greg Kroah-Hartman

dlm: Don't swamp the CPU with callbacks queued during recovery

2018-11-08T19:17:00+00:00

Before this patch, recovery would cause all callbacks to be delayed, put on a queue, and afterward they were all queued to the callback work queue. This patch does the same thing, but occasionally takes a break after 25 of them so it won't swamp the CPU at the expense of other RT processes like corosync. Signed-off-by: Bob Peterson Signed-off-by: David Teigland

DLM: fix overflow dlm_cb_seq

2017-09-25T17:45:21+00:00

dlm_cb_seq is 64 bits. If dlm_cb_seq overflows and returns to 0, dlm_rem_lkb_callback() will not work properly. Signed-off-by: Tadashi Miyauchi Signed-off-by: Tsutomu Owa Signed-off-by: David Teigland

dlm: don't specify WQ_UNBOUND for the ast callback workqueue

2016-10-19T16:13:04+00:00

This patch removes the WQ_UNBOUND flag (which implies WQ_HIGHPRI) from the DLM's ast work queue, in favor of just WQ_HIGHPRI. This has been shown to cause a 19 percent performance increase for simultaneous inode creates on GFS2 with fs_mark. Signed-off-by: Bob Peterson Signed-off-by: David Teigland