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8e854e9c GR |
1 | /* |
2 | * Copyright (C) 2015, SUSE | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2, or (at your option) | |
7 | * any later version. | |
8 | * | |
9 | */ | |
10 | ||
11 | ||
12 | #include <linux/module.h> | |
47741b7c GR |
13 | #include <linux/dlm.h> |
14 | #include <linux/sched.h> | |
15 | #include "md.h" | |
edb39c9d | 16 | #include "md-cluster.h" |
47741b7c GR |
17 | |
18 | #define LVB_SIZE 64 | |
19 | ||
20 | struct dlm_lock_resource { | |
21 | dlm_lockspace_t *ls; | |
22 | struct dlm_lksb lksb; | |
23 | char *name; /* lock name. */ | |
24 | uint32_t flags; /* flags to pass to dlm_lock() */ | |
47741b7c | 25 | struct completion completion; /* completion for synchronized locking */ |
c4ce867f GR |
26 | void (*bast)(void *arg, int mode); /* blocking AST function pointer*/ |
27 | struct mddev *mddev; /* pointing back to mddev. */ | |
28 | }; | |
29 | ||
30 | struct md_cluster_info { | |
31 | /* dlm lock space and resources for clustered raid. */ | |
32 | dlm_lockspace_t *lockspace; | |
33 | struct dlm_lock_resource *sb_lock; | |
34 | struct mutex sb_mutex; | |
47741b7c GR |
35 | }; |
36 | ||
37 | static void sync_ast(void *arg) | |
38 | { | |
39 | struct dlm_lock_resource *res; | |
40 | ||
41 | res = (struct dlm_lock_resource *) arg; | |
42 | complete(&res->completion); | |
43 | } | |
44 | ||
45 | static int dlm_lock_sync(struct dlm_lock_resource *res, int mode) | |
46 | { | |
47 | int ret = 0; | |
48 | ||
49 | init_completion(&res->completion); | |
50 | ret = dlm_lock(res->ls, mode, &res->lksb, | |
51 | res->flags, res->name, strlen(res->name), | |
52 | 0, sync_ast, res, res->bast); | |
53 | if (ret) | |
54 | return ret; | |
55 | wait_for_completion(&res->completion); | |
56 | return res->lksb.sb_status; | |
57 | } | |
58 | ||
59 | static int dlm_unlock_sync(struct dlm_lock_resource *res) | |
60 | { | |
61 | return dlm_lock_sync(res, DLM_LOCK_NL); | |
62 | } | |
63 | ||
c4ce867f | 64 | static struct dlm_lock_resource *lockres_init(struct mddev *mddev, |
47741b7c GR |
65 | char *name, void (*bastfn)(void *arg, int mode), int with_lvb) |
66 | { | |
67 | struct dlm_lock_resource *res = NULL; | |
68 | int ret, namelen; | |
c4ce867f | 69 | struct md_cluster_info *cinfo = mddev->cluster_info; |
47741b7c GR |
70 | |
71 | res = kzalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL); | |
72 | if (!res) | |
73 | return NULL; | |
c4ce867f GR |
74 | res->ls = cinfo->lockspace; |
75 | res->mddev = mddev; | |
47741b7c GR |
76 | namelen = strlen(name); |
77 | res->name = kzalloc(namelen + 1, GFP_KERNEL); | |
78 | if (!res->name) { | |
79 | pr_err("md-cluster: Unable to allocate resource name for resource %s\n", name); | |
80 | goto out_err; | |
81 | } | |
82 | strlcpy(res->name, name, namelen + 1); | |
83 | if (with_lvb) { | |
84 | res->lksb.sb_lvbptr = kzalloc(LVB_SIZE, GFP_KERNEL); | |
85 | if (!res->lksb.sb_lvbptr) { | |
86 | pr_err("md-cluster: Unable to allocate LVB for resource %s\n", name); | |
87 | goto out_err; | |
88 | } | |
89 | res->flags = DLM_LKF_VALBLK; | |
90 | } | |
91 | ||
92 | if (bastfn) | |
93 | res->bast = bastfn; | |
94 | ||
95 | res->flags |= DLM_LKF_EXPEDITE; | |
96 | ||
97 | ret = dlm_lock_sync(res, DLM_LOCK_NL); | |
98 | if (ret) { | |
99 | pr_err("md-cluster: Unable to lock NL on new lock resource %s\n", name); | |
100 | goto out_err; | |
101 | } | |
102 | res->flags &= ~DLM_LKF_EXPEDITE; | |
103 | res->flags |= DLM_LKF_CONVERT; | |
104 | ||
105 | return res; | |
106 | out_err: | |
107 | kfree(res->lksb.sb_lvbptr); | |
108 | kfree(res->name); | |
109 | kfree(res); | |
110 | return NULL; | |
111 | } | |
112 | ||
113 | static void lockres_free(struct dlm_lock_resource *res) | |
114 | { | |
115 | if (!res) | |
116 | return; | |
117 | ||
118 | init_completion(&res->completion); | |
119 | dlm_unlock(res->ls, res->lksb.sb_lkid, 0, &res->lksb, res); | |
120 | wait_for_completion(&res->completion); | |
121 | ||
122 | kfree(res->name); | |
123 | kfree(res->lksb.sb_lvbptr); | |
124 | kfree(res); | |
125 | } | |
8e854e9c | 126 | |
c4ce867f GR |
127 | static char *pretty_uuid(char *dest, char *src) |
128 | { | |
129 | int i, len = 0; | |
130 | ||
131 | for (i = 0; i < 16; i++) { | |
132 | if (i == 4 || i == 6 || i == 8 || i == 10) | |
133 | len += sprintf(dest + len, "-"); | |
134 | len += sprintf(dest + len, "%02x", (__u8)src[i]); | |
135 | } | |
136 | return dest; | |
137 | } | |
138 | ||
edb39c9d GR |
139 | static int join(struct mddev *mddev, int nodes) |
140 | { | |
c4ce867f GR |
141 | struct md_cluster_info *cinfo; |
142 | int ret; | |
143 | char str[64]; | |
144 | ||
145 | if (!try_module_get(THIS_MODULE)) | |
146 | return -ENOENT; | |
147 | ||
148 | cinfo = kzalloc(sizeof(struct md_cluster_info), GFP_KERNEL); | |
149 | if (!cinfo) | |
150 | return -ENOMEM; | |
151 | ||
152 | memset(str, 0, 64); | |
153 | pretty_uuid(str, mddev->uuid); | |
154 | ret = dlm_new_lockspace(str, NULL, DLM_LSFL_FS, LVB_SIZE, | |
155 | NULL, NULL, NULL, &cinfo->lockspace); | |
156 | if (ret) | |
157 | goto err; | |
158 | cinfo->sb_lock = lockres_init(mddev, "cmd-super", | |
159 | NULL, 0); | |
160 | if (!cinfo->sb_lock) { | |
161 | ret = -ENOMEM; | |
162 | goto err; | |
163 | } | |
164 | mutex_init(&cinfo->sb_mutex); | |
165 | mddev->cluster_info = cinfo; | |
edb39c9d | 166 | return 0; |
c4ce867f GR |
167 | err: |
168 | if (cinfo->lockspace) | |
169 | dlm_release_lockspace(cinfo->lockspace, 2); | |
170 | kfree(cinfo); | |
171 | module_put(THIS_MODULE); | |
172 | return ret; | |
edb39c9d GR |
173 | } |
174 | ||
175 | static int leave(struct mddev *mddev) | |
176 | { | |
c4ce867f GR |
177 | struct md_cluster_info *cinfo = mddev->cluster_info; |
178 | ||
179 | if (!cinfo) | |
180 | return 0; | |
181 | lockres_free(cinfo->sb_lock); | |
182 | dlm_release_lockspace(cinfo->lockspace, 2); | |
edb39c9d GR |
183 | return 0; |
184 | } | |
185 | ||
186 | static struct md_cluster_operations cluster_ops = { | |
187 | .join = join, | |
188 | .leave = leave, | |
189 | }; | |
190 | ||
8e854e9c GR |
191 | static int __init cluster_init(void) |
192 | { | |
193 | pr_warn("md-cluster: EXPERIMENTAL. Use with caution\n"); | |
194 | pr_info("Registering Cluster MD functions\n"); | |
edb39c9d | 195 | register_md_cluster_operations(&cluster_ops, THIS_MODULE); |
8e854e9c GR |
196 | return 0; |
197 | } | |
198 | ||
199 | static void cluster_exit(void) | |
200 | { | |
edb39c9d | 201 | unregister_md_cluster_operations(); |
8e854e9c GR |
202 | } |
203 | ||
204 | module_init(cluster_init); | |
205 | module_exit(cluster_exit); | |
206 | MODULE_LICENSE("GPL"); | |
207 | MODULE_DESCRIPTION("Clustering support for MD"); |