47741b7ca7
A dlm_lock_resource is a structure which contains all information required for locking using DLM. The init function allocates the lock and acquires the lock in NL mode. The unlock function converts the lock resource to NL mode. This is done to preserve LVB and for faster processing of locks. The lock resource is DLM unlocked only in the lockres_free function, which is the end of life of the lock resource. Signed-off-by: Lidong Zhong <lzhong@suse.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
131 lines
3.0 KiB
C
131 lines
3.0 KiB
C
/*
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* Copyright (C) 2015, SUSE
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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*/
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#include <linux/module.h>
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#include <linux/dlm.h>
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#include <linux/sched.h>
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#include "md.h"
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#define LVB_SIZE 64
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struct dlm_lock_resource {
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dlm_lockspace_t *ls;
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struct dlm_lksb lksb;
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char *name; /* lock name. */
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uint32_t flags; /* flags to pass to dlm_lock() */
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void (*bast)(void *arg, int mode); /* blocking AST function pointer*/
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struct completion completion; /* completion for synchronized locking */
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};
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static void sync_ast(void *arg)
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{
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struct dlm_lock_resource *res;
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res = (struct dlm_lock_resource *) arg;
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complete(&res->completion);
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}
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static int dlm_lock_sync(struct dlm_lock_resource *res, int mode)
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{
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int ret = 0;
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init_completion(&res->completion);
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ret = dlm_lock(res->ls, mode, &res->lksb,
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res->flags, res->name, strlen(res->name),
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0, sync_ast, res, res->bast);
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if (ret)
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return ret;
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wait_for_completion(&res->completion);
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return res->lksb.sb_status;
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}
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static int dlm_unlock_sync(struct dlm_lock_resource *res)
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{
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return dlm_lock_sync(res, DLM_LOCK_NL);
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}
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static struct dlm_lock_resource *lockres_init(dlm_lockspace_t *lockspace,
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char *name, void (*bastfn)(void *arg, int mode), int with_lvb)
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{
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struct dlm_lock_resource *res = NULL;
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int ret, namelen;
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res = kzalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
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if (!res)
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return NULL;
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res->ls = lockspace;
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namelen = strlen(name);
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res->name = kzalloc(namelen + 1, GFP_KERNEL);
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if (!res->name) {
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pr_err("md-cluster: Unable to allocate resource name for resource %s\n", name);
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goto out_err;
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}
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strlcpy(res->name, name, namelen + 1);
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if (with_lvb) {
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res->lksb.sb_lvbptr = kzalloc(LVB_SIZE, GFP_KERNEL);
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if (!res->lksb.sb_lvbptr) {
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pr_err("md-cluster: Unable to allocate LVB for resource %s\n", name);
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goto out_err;
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}
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res->flags = DLM_LKF_VALBLK;
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}
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if (bastfn)
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res->bast = bastfn;
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res->flags |= DLM_LKF_EXPEDITE;
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ret = dlm_lock_sync(res, DLM_LOCK_NL);
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if (ret) {
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pr_err("md-cluster: Unable to lock NL on new lock resource %s\n", name);
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goto out_err;
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}
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res->flags &= ~DLM_LKF_EXPEDITE;
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res->flags |= DLM_LKF_CONVERT;
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return res;
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out_err:
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kfree(res->lksb.sb_lvbptr);
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kfree(res->name);
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kfree(res);
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return NULL;
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}
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static void lockres_free(struct dlm_lock_resource *res)
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{
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if (!res)
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return;
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init_completion(&res->completion);
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dlm_unlock(res->ls, res->lksb.sb_lkid, 0, &res->lksb, res);
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wait_for_completion(&res->completion);
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kfree(res->name);
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kfree(res->lksb.sb_lvbptr);
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kfree(res);
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}
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static int __init cluster_init(void)
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{
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pr_warn("md-cluster: EXPERIMENTAL. Use with caution\n");
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pr_info("Registering Cluster MD functions\n");
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return 0;
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}
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static void cluster_exit(void)
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{
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}
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module_init(cluster_init);
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module_exit(cluster_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Clustering support for MD");
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