OpenCloudOS-Kernel/fs/dlm/lowcomms.h

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/* SPDX-License-Identifier: GPL-2.0-only */
/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
******************************************************************************/
#ifndef __LOWCOMMS_DOT_H__
#define __LOWCOMMS_DOT_H__
fs: dlm: add reliable connection if reconnect This patch introduce to make a tcp lowcomms connection reliable even if reconnects occurs. This is done by an application layer re-transmission handling and sequence numbers in dlm protocols. There are three new dlm commands: DLM_OPTS: This will encapsulate an existing dlm message (and rcom message if they don't have an own application side re-transmission handling). As optional handling additional tlv's (type length fields) can be appended. This can be for example a sequence number field. However because in DLM_OPTS the lockspace field is unused and a sequence number is a mandatory field it isn't made as a tlv and we put the sequence number inside the lockspace id. The possibility to add optional options are still there for future purposes. DLM_ACK: Just a dlm header to acknowledge the receive of a DLM_OPTS message to it's sender. DLM_FIN: This provides a 4 way handshake for connection termination inclusive support for half-closed connections. It's provided on application layer because SCTP doesn't support half-closed sockets, the shutdown() call can interrupted by e.g. TCP resets itself and a hard logic to implement it because the othercon paradigm in lowcomms. The 4-way termination handshake also solve problems to synchronize peer EOF arrival and that the cluster manager removes the peer in the node membership handling of DLM. In some cases messages can be still transmitted in this time and we need to wait for the node membership event. To provide a reliable connection the node will retransmit all unacknowledges message to it's peer on reconnect. The receiver will then filtering out the next received message and drop all messages which are duplicates. As RCOM_STATUS and RCOM_NAMES messages are the first messages which are exchanged and they have they own re-transmission handling, there exists logic that these messages must be first. If these messages arrives we store the dlm version field. This handling is on DLM 3.1 and after this patch 3.2 the same. A backwards compatibility handling has been added which seems to work on tests without tcpkill, however it's not recommended to use DLM 3.1 and 3.2 at the same time, because DLM 3.2 tries to fix long term bugs in the DLM protocol. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
2021-05-22 03:08:46 +08:00
#include "dlm_internal.h"
#define DLM_MIDCOMMS_OPT_LEN sizeof(struct dlm_opts)
#define DLM_MAX_APP_BUFSIZE (DLM_MAX_SOCKET_BUFSIZE - \
fs: dlm: add reliable connection if reconnect This patch introduce to make a tcp lowcomms connection reliable even if reconnects occurs. This is done by an application layer re-transmission handling and sequence numbers in dlm protocols. There are three new dlm commands: DLM_OPTS: This will encapsulate an existing dlm message (and rcom message if they don't have an own application side re-transmission handling). As optional handling additional tlv's (type length fields) can be appended. This can be for example a sequence number field. However because in DLM_OPTS the lockspace field is unused and a sequence number is a mandatory field it isn't made as a tlv and we put the sequence number inside the lockspace id. The possibility to add optional options are still there for future purposes. DLM_ACK: Just a dlm header to acknowledge the receive of a DLM_OPTS message to it's sender. DLM_FIN: This provides a 4 way handshake for connection termination inclusive support for half-closed connections. It's provided on application layer because SCTP doesn't support half-closed sockets, the shutdown() call can interrupted by e.g. TCP resets itself and a hard logic to implement it because the othercon paradigm in lowcomms. The 4-way termination handshake also solve problems to synchronize peer EOF arrival and that the cluster manager removes the peer in the node membership handling of DLM. In some cases messages can be still transmitted in this time and we need to wait for the node membership event. To provide a reliable connection the node will retransmit all unacknowledges message to it's peer on reconnect. The receiver will then filtering out the next received message and drop all messages which are duplicates. As RCOM_STATUS and RCOM_NAMES messages are the first messages which are exchanged and they have they own re-transmission handling, there exists logic that these messages must be first. If these messages arrives we store the dlm version field. This handling is on DLM 3.1 and after this patch 3.2 the same. A backwards compatibility handling has been added which seems to work on tests without tcpkill, however it's not recommended to use DLM 3.1 and 3.2 at the same time, because DLM 3.2 tries to fix long term bugs in the DLM protocol. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
2021-05-22 03:08:46 +08:00
DLM_MIDCOMMS_OPT_LEN)
#define CONN_HASH_SIZE 32
/* This is deliberately very simple because most clusters have simple
* sequential nodeids, so we should be able to go straight to a connection
* struct in the array
*/
static inline int nodeid_hash(int nodeid)
{
return nodeid & (CONN_HASH_SIZE-1);
}
/* check if dlm is running */
bool dlm_lowcomms_is_running(void);
int dlm_lowcomms_start(void);
fs: dlm: add shutdown hook This patch fixes issues which occurs when dlm lowcomms synchronize their workqueues but dlm application layer already released the lockspace. In such cases messages like: dlm: gfs2: release_lockspace final free dlm: invalid lockspace 3841231384 from 1 cmd 1 type 11 are printed on the kernel log. This patch is solving this issue by introducing a new "shutdown" hook before calling "stop" hook when the lockspace is going to be released finally. This should pretend any dlm messages sitting in the workqueues during or after lockspace removal. It's necessary to call dlm_scand_stop() as I instrumented dlm_lowcomms_get_buffer() code to report a warning after it's called after dlm_midcomms_shutdown() functionality, see below: WARNING: CPU: 1 PID: 3794 at fs/dlm/midcomms.c:1003 dlm_midcomms_get_buffer+0x167/0x180 Modules linked in: joydev iTCO_wdt intel_pmc_bxt iTCO_vendor_support drm_ttm_helper ttm pcspkr serio_raw i2c_i801 i2c_smbus drm_kms_helper virtio_scsi lpc_ich virtio_balloon virtio_console xhci_pci xhci_pci_renesas cec qemu_fw_cfg drm [last unloaded: qxl] CPU: 1 PID: 3794 Comm: dlm_scand Tainted: G W 5.11.0+ #26 Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.13.0-2.module+el8.3.0+7353+9de0a3cc 04/01/2014 RIP: 0010:dlm_midcomms_get_buffer+0x167/0x180 Code: 5d 41 5c 41 5d 41 5e 41 5f c3 0f 0b 45 31 e4 5b 5d 4c 89 e0 41 5c 41 5d 41 5e 41 5f c3 4c 89 e7 45 31 e4 e8 3b f1 ec ff eb 86 <0f> 0b 4c 89 e7 45 31 e4 e8 2c f1 ec ff e9 74 ff ff ff 0f 1f 80 00 RSP: 0018:ffffa81503f8fe60 EFLAGS: 00010202 RAX: 0000000000000008 RBX: ffff8f969827f200 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffffad1e89a0 RDI: ffff8f96a5294160 RBP: 0000000000000001 R08: 0000000000000000 R09: ffff8f96a250bc60 R10: 00000000000045d3 R11: 0000000000000000 R12: ffff8f96a250bc60 R13: ffffa81503f8fec8 R14: 0000000000000070 R15: 0000000000000c40 FS: 0000000000000000(0000) GS:ffff8f96fbc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055aa3351c000 CR3: 000000010bf22000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dlm_scan_rsbs+0x420/0x670 ? dlm_uevent+0x20/0x20 dlm_scand+0xbf/0xe0 kthread+0x13a/0x150 ? __kthread_bind_mask+0x60/0x60 ret_from_fork+0x22/0x30 To synchronize all dlm scand messages we stop it right before shutdown hook. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
2021-03-02 06:05:20 +08:00
void dlm_lowcomms_shutdown(void);
fs: dlm: remove socket shutdown handling Since commit 489d8e559c65 ("fs: dlm: add reliable connection if reconnect") we have functionality like TCP offers for half-closed sockets on dlm application protocol layer. This feature is required because the cluster manager events about leaving resource memberships can be locally already occurred but other cluster nodes having a pending leaving membership over the cluster manager protocol happening. In this time the local dlm node already shutdown it's connection and don't transmit anymore any new dlm messages, but however it still needs to be able to accept dlm messages because the pending leave membership request of the cluster manager protocol which the dlm kernel implementation has no control about it. We have this functionality on the application for two reasons, the main reason is that SCTP does not support such functionality on socket layer. But we can do it inside application layer. Another small issue is that this feature is broken in the TCP world because some NAT devices does not implement such functionality correctly. This is the same reason why the reliable connection session layer in DLM exists. We give up on middle devices in the networking which sends e.g. TCP resets out. In DLM we cannot have any message dropping and we ensure it over a session layer that it can't happen. Back to the half-closed grace shutdown handling. It's not necessary anymore to do it on socket layer (which is only support for TCP sockets) because we do it on application layer. This patch removes this handling, if there are still issues then we have a problem on the application layer for such handling. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
2022-11-18 06:11:50 +08:00
void dlm_lowcomms_shutdown_node(int nodeid, bool force);
void dlm_lowcomms_stop(void);
void dlm_lowcomms_init(void);
void dlm_lowcomms_exit(void);
int dlm_lowcomms_close(int nodeid);
struct dlm_msg *dlm_lowcomms_new_msg(int nodeid, int len, gfp_t allocation,
char **ppc, void (*cb)(void *data),
void *data);
void dlm_lowcomms_commit_msg(struct dlm_msg *msg);
void dlm_lowcomms_put_msg(struct dlm_msg *msg);
int dlm_lowcomms_resend_msg(struct dlm_msg *msg);
int dlm_lowcomms_connect_node(int nodeid);
fs: dlm: fix mark setting deadlock This patch fixes an deadlock issue when dlm_lowcomms_close() is called. When dlm_lowcomms_close() is called the clusters_root.subsys.su_mutex is held to remove configfs items. At this time we flushing (e.g. cancel_work_sync()) the workers of send and recv workqueue. Due the fact that we accessing configfs items (mark values), these workers will lock clusters_root.subsys.su_mutex as well which are already hold by dlm_lowcomms_close() and ends in a deadlock situation. [67170.703046] ====================================================== [67170.703965] WARNING: possible circular locking dependency detected [67170.704758] 5.11.0-rc4+ #22 Tainted: G W [67170.705433] ------------------------------------------------------ [67170.706228] dlm_controld/280 is trying to acquire lock: [67170.706915] ffff9f2f475a6948 ((wq_completion)dlm_recv){+.+.}-{0:0}, at: __flush_work+0x203/0x4c0 [67170.708026] but task is already holding lock: [67170.708758] ffffffffa132f878 (&clusters_root.subsys.su_mutex){+.+.}-{3:3}, at: configfs_rmdir+0x29b/0x310 [67170.710016] which lock already depends on the new lock. The new behaviour adds the mark value to the node address configuration which doesn't require to held the clusters_root.subsys.su_mutex by accessing mark values in a separate datastructure. However the mark values can be set now only after a node address was set which is the case when the user is using dlm_controld. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
2021-03-02 06:05:09 +08:00
int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark);
int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len);
void dlm_midcomms_receive_done(int nodeid);
struct kmem_cache *dlm_lowcomms_writequeue_cache_create(void);
struct kmem_cache *dlm_lowcomms_msg_cache_create(void);
#endif /* __LOWCOMMS_DOT_H__ */