1 /* 2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. 3 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. 4 * 5 * This copyrighted material is made available to anyone wishing to use, 6 * modify, copy, or redistribute it subject to the terms and conditions 7 * of the GNU General Public License version 2. 8 */ 9 10 #ifndef __GLOCK_DOT_H__ 11 #define __GLOCK_DOT_H__ 12 13 #include <linux/sched.h> 14 #include <linux/parser.h> 15 #include "incore.h" 16 #include "util.h" 17 18 /* Options for hostdata parser */ 19 20 enum { 21 Opt_jid, 22 Opt_id, 23 Opt_first, 24 Opt_nodir, 25 Opt_err, 26 }; 27 28 /* 29 * lm_lockname types 30 */ 31 32 #define LM_TYPE_RESERVED 0x00 33 #define LM_TYPE_NONDISK 0x01 34 #define LM_TYPE_INODE 0x02 35 #define LM_TYPE_RGRP 0x03 36 #define LM_TYPE_META 0x04 37 #define LM_TYPE_IOPEN 0x05 38 #define LM_TYPE_FLOCK 0x06 39 #define LM_TYPE_PLOCK 0x07 40 #define LM_TYPE_QUOTA 0x08 41 #define LM_TYPE_JOURNAL 0x09 42 43 /* 44 * lm_lock() states 45 * 46 * SHARED is compatible with SHARED, not with DEFERRED or EX. 47 * DEFERRED is compatible with DEFERRED, not with SHARED or EX. 48 */ 49 50 #define LM_ST_UNLOCKED 0 51 #define LM_ST_EXCLUSIVE 1 52 #define LM_ST_DEFERRED 2 53 #define LM_ST_SHARED 3 54 55 /* 56 * lm_lock() flags 57 * 58 * LM_FLAG_TRY 59 * Don't wait to acquire the lock if it can't be granted immediately. 60 * 61 * LM_FLAG_TRY_1CB 62 * Send one blocking callback if TRY is set and the lock is not granted. 63 * 64 * LM_FLAG_NOEXP 65 * GFS sets this flag on lock requests it makes while doing journal recovery. 66 * These special requests should not be blocked due to the recovery like 67 * ordinary locks would be. 68 * 69 * LM_FLAG_ANY 70 * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may 71 * also be granted in SHARED. The preferred state is whichever is compatible 72 * with other granted locks, or the specified state if no other locks exist. 73 * 74 * LM_FLAG_PRIORITY 75 * Override fairness considerations. Suppose a lock is held in a shared state 76 * and there is a pending request for the deferred state. A shared lock 77 * request with the priority flag would be allowed to bypass the deferred 78 * request and directly join the other shared lock. A shared lock request 79 * without the priority flag might be forced to wait until the deferred 80 * requested had acquired and released the lock. 81 */ 82 83 #define LM_FLAG_TRY 0x0001 84 #define LM_FLAG_TRY_1CB 0x0002 85 #define LM_FLAG_NOEXP 0x0004 86 #define LM_FLAG_ANY 0x0008 87 #define LM_FLAG_PRIORITY 0x0010 88 #define GL_ASYNC 0x0040 89 #define GL_EXACT 0x0080 90 #define GL_SKIP 0x0100 91 #define GL_NOCACHE 0x0400 92 93 /* 94 * lm_async_cb return flags 95 * 96 * LM_OUT_ST_MASK 97 * Masks the lower two bits of lock state in the returned value. 98 * 99 * LM_OUT_CANCELED 100 * The lock request was canceled. 101 * 102 */ 103 104 #define LM_OUT_ST_MASK 0x00000003 105 #define LM_OUT_CANCELED 0x00000008 106 #define LM_OUT_ERROR 0x00000004 107 108 /* 109 * lm_recovery_done() messages 110 */ 111 112 #define LM_RD_GAVEUP 308 113 #define LM_RD_SUCCESS 309 114 115 #define GLR_TRYFAILED 13 116 117 #define GL_GLOCK_MAX_HOLD (long)(HZ / 5) 118 #define GL_GLOCK_DFT_HOLD (long)(HZ / 5) 119 #define GL_GLOCK_MIN_HOLD (long)(10) 120 #define GL_GLOCK_HOLD_INCR (long)(HZ / 20) 121 #define GL_GLOCK_HOLD_DECR (long)(HZ / 40) 122 123 struct lm_lockops { 124 const char *lm_proto_name; 125 int (*lm_mount) (struct gfs2_sbd *sdp, const char *table); 126 void (*lm_first_done) (struct gfs2_sbd *sdp); 127 void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid, 128 unsigned int result); 129 void (*lm_unmount) (struct gfs2_sbd *sdp); 130 void (*lm_withdraw) (struct gfs2_sbd *sdp); 131 void (*lm_put_lock) (struct gfs2_glock *gl); 132 int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state, 133 unsigned int flags); 134 void (*lm_cancel) (struct gfs2_glock *gl); 135 const match_table_t *lm_tokens; 136 }; 137 138 extern struct workqueue_struct *gfs2_delete_workqueue; 139 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl) 140 { 141 struct gfs2_holder *gh; 142 struct pid *pid; 143 144 /* Look in glock's list of holders for one with current task as owner */ 145 spin_lock(&gl->gl_lockref.lock); 146 pid = task_pid(current); 147 list_for_each_entry(gh, &gl->gl_holders, gh_list) { 148 if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) 149 break; 150 if (gh->gh_owner_pid == pid) 151 goto out; 152 } 153 gh = NULL; 154 out: 155 spin_unlock(&gl->gl_lockref.lock); 156 157 return gh; 158 } 159 160 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl) 161 { 162 return gl->gl_state == LM_ST_EXCLUSIVE; 163 } 164 165 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl) 166 { 167 return gl->gl_state == LM_ST_DEFERRED; 168 } 169 170 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl) 171 { 172 return gl->gl_state == LM_ST_SHARED; 173 } 174 175 static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl) 176 { 177 if (gl->gl_ops->go_flags & GLOF_ASPACE) 178 return (struct address_space *)(gl + 1); 179 return NULL; 180 } 181 182 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 183 const struct gfs2_glock_operations *glops, 184 int create, struct gfs2_glock **glp); 185 extern void gfs2_glock_hold(struct gfs2_glock *gl); 186 extern void gfs2_glock_put(struct gfs2_glock *gl); 187 extern void gfs2_glock_queue_put(struct gfs2_glock *gl); 188 extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, 189 u16 flags, struct gfs2_holder *gh); 190 extern void gfs2_holder_reinit(unsigned int state, u16 flags, 191 struct gfs2_holder *gh); 192 extern void gfs2_holder_uninit(struct gfs2_holder *gh); 193 extern int gfs2_glock_nq(struct gfs2_holder *gh); 194 extern int gfs2_glock_poll(struct gfs2_holder *gh); 195 extern int gfs2_glock_wait(struct gfs2_holder *gh); 196 extern void gfs2_glock_dq(struct gfs2_holder *gh); 197 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh); 198 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh); 199 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number, 200 const struct gfs2_glock_operations *glops, 201 unsigned int state, u16 flags, 202 struct gfs2_holder *gh); 203 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs); 204 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs); 205 extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl); 206 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { gfs2_dump_glock(NULL, gl); BUG(); } } while(0) 207 extern __printf(2, 3) 208 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...); 209 210 /** 211 * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock 212 * @gl: the glock 213 * @state: the state we're requesting 214 * @flags: the modifier flags 215 * @gh: the holder structure 216 * 217 * Returns: 0, GLR_*, or errno 218 */ 219 220 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl, 221 unsigned int state, u16 flags, 222 struct gfs2_holder *gh) 223 { 224 int error; 225 226 gfs2_holder_init(gl, state, flags, gh); 227 228 error = gfs2_glock_nq(gh); 229 if (error) 230 gfs2_holder_uninit(gh); 231 232 return error; 233 } 234 235 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state); 236 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret); 237 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp); 238 extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip); 239 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp); 240 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl); 241 extern void gfs2_glock_free(struct gfs2_glock *gl); 242 243 extern int __init gfs2_glock_init(void); 244 extern void gfs2_glock_exit(void); 245 246 extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp); 247 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp); 248 extern void gfs2_register_debugfs(void); 249 extern void gfs2_unregister_debugfs(void); 250 251 extern const struct lm_lockops gfs2_dlm_ops; 252 253 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh) 254 { 255 gh->gh_gl = NULL; 256 } 257 258 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh) 259 { 260 return gh->gh_gl; 261 } 262 263 /** 264 * glock_set_object - set the gl_object field of a glock 265 * @gl: the glock 266 * @object: the object 267 */ 268 static inline void glock_set_object(struct gfs2_glock *gl, void *object) 269 { 270 spin_lock(&gl->gl_lockref.lock); 271 if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL)) 272 gfs2_dump_glock(NULL, gl); 273 gl->gl_object = object; 274 spin_unlock(&gl->gl_lockref.lock); 275 } 276 277 /** 278 * glock_clear_object - clear the gl_object field of a glock 279 * @gl: the glock 280 * @object: the object 281 * 282 * I'd love to similarly add this: 283 * else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object)) 284 * gfs2_dump_glock(NULL, gl); 285 * Unfortunately, that's not possible because as soon as gfs2_delete_inode 286 * frees the block in the rgrp, another process can reassign it for an I_NEW 287 * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget. 288 * That means gfs2_delete_inode may subsequently try to call this function 289 * for a glock that's already pointing to a brand new inode. If we clear the 290 * new inode's gl_object, we'll introduce metadata corruption. Function 291 * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also 292 * tries to clear gl_object, so it's more than just gfs2_delete_inode. 293 * 294 */ 295 static inline void glock_clear_object(struct gfs2_glock *gl, void *object) 296 { 297 spin_lock(&gl->gl_lockref.lock); 298 if (gl->gl_object == object) 299 gl->gl_object = NULL; 300 spin_unlock(&gl->gl_lockref.lock); 301 } 302 303 #endif /* __GLOCK_DOT_H__ */ 304