2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright 2004-2011 Red Hat, Inc.
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.
11 #include <linux/dlm.h>
12 #include <linux/slab.h>
13 #include <linux/types.h>
14 #include <linux/delay.h>
15 #include <linux/gfs2_ondisk.h>
21 #include "trace_gfs2.h"
23 extern struct workqueue_struct
*gfs2_control_wq
;
26 * gfs2_update_stats - Update time based stats
27 * @mv: Pointer to mean/variance structure to update
28 * @sample: New data to include
30 * @delta is the difference between the current rtt sample and the
31 * running average srtt. We add 1/8 of that to the srtt in order to
32 * update the current srtt estimate. The varience estimate is a bit
33 * more complicated. We subtract the abs value of the @delta from
34 * the current variance estimate and add 1/4 of that to the running
37 * Note that the index points at the array entry containing the smoothed
38 * mean value, and the variance is always in the following entry
40 * Reference: TCP/IP Illustrated, vol 2, p. 831,832
41 * All times are in units of integer nanoseconds. Unlike the TCP/IP case,
42 * they are not scaled fixed point.
45 static inline void gfs2_update_stats(struct gfs2_lkstats
*s
, unsigned index
,
48 s64 delta
= sample
- s
->stats
[index
];
49 s
->stats
[index
] += (delta
>> 3);
51 s
->stats
[index
] += ((abs64(delta
) - s
->stats
[index
]) >> 2);
55 * gfs2_update_reply_times - Update locking statistics
56 * @gl: The glock to update
58 * This assumes that gl->gl_dstamp has been set earlier.
60 * The rtt (lock round trip time) is an estimate of the time
61 * taken to perform a dlm lock request. We update it on each
64 * The blocking flag is set on the glock for all dlm requests
65 * which may potentially block due to lock requests from other nodes.
66 * DLM requests where the current lock state is exclusive, the
67 * requested state is null (or unlocked) or where the TRY or
68 * TRY_1CB flags are set are classified as non-blocking. All
69 * other DLM requests are counted as (potentially) blocking.
71 static inline void gfs2_update_reply_times(struct gfs2_glock
*gl
)
73 struct gfs2_pcpu_lkstats
*lks
;
74 const unsigned gltype
= gl
->gl_name
.ln_type
;
75 unsigned index
= test_bit(GLF_BLOCKING
, &gl
->gl_flags
) ?
76 GFS2_LKS_SRTTB
: GFS2_LKS_SRTT
;
80 rtt
= ktime_to_ns(ktime_sub(ktime_get_real(), gl
->gl_dstamp
));
81 lks
= this_cpu_ptr(gl
->gl_sbd
->sd_lkstats
);
82 gfs2_update_stats(&gl
->gl_stats
, index
, rtt
); /* Local */
83 gfs2_update_stats(&lks
->lkstats
[gltype
], index
, rtt
); /* Global */
86 trace_gfs2_glock_lock_time(gl
, rtt
);
90 * gfs2_update_request_times - Update locking statistics
91 * @gl: The glock to update
93 * The irt (lock inter-request times) measures the average time
94 * between requests to the dlm. It is updated immediately before
98 static inline void gfs2_update_request_times(struct gfs2_glock
*gl
)
100 struct gfs2_pcpu_lkstats
*lks
;
101 const unsigned gltype
= gl
->gl_name
.ln_type
;
106 dstamp
= gl
->gl_dstamp
;
107 gl
->gl_dstamp
= ktime_get_real();
108 irt
= ktime_to_ns(ktime_sub(gl
->gl_dstamp
, dstamp
));
109 lks
= this_cpu_ptr(gl
->gl_sbd
->sd_lkstats
);
110 gfs2_update_stats(&gl
->gl_stats
, GFS2_LKS_SIRT
, irt
); /* Local */
111 gfs2_update_stats(&lks
->lkstats
[gltype
], GFS2_LKS_SIRT
, irt
); /* Global */
115 static void gdlm_ast(void *arg
)
117 struct gfs2_glock
*gl
= arg
;
118 unsigned ret
= gl
->gl_state
;
120 gfs2_update_reply_times(gl
);
121 BUG_ON(gl
->gl_lksb
.sb_flags
& DLM_SBF_DEMOTED
);
123 if ((gl
->gl_lksb
.sb_flags
& DLM_SBF_VALNOTVALID
) && gl
->gl_lksb
.sb_lvbptr
)
124 memset(gl
->gl_lksb
.sb_lvbptr
, 0, GDLM_LVB_SIZE
);
126 switch (gl
->gl_lksb
.sb_status
) {
127 case -DLM_EUNLOCK
: /* Unlocked, so glock can be freed */
130 case -DLM_ECANCEL
: /* Cancel while getting lock */
131 ret
|= LM_OUT_CANCELED
;
133 case -EAGAIN
: /* Try lock fails */
134 case -EDEADLK
: /* Deadlock detected */
136 case -ETIMEDOUT
: /* Canceled due to timeout */
139 case 0: /* Success */
141 default: /* Something unexpected */
146 if (gl
->gl_lksb
.sb_flags
& DLM_SBF_ALTMODE
) {
147 if (gl
->gl_req
== LM_ST_SHARED
)
148 ret
= LM_ST_DEFERRED
;
149 else if (gl
->gl_req
== LM_ST_DEFERRED
)
155 set_bit(GLF_INITIAL
, &gl
->gl_flags
);
156 gfs2_glock_complete(gl
, ret
);
159 if (!test_bit(GLF_INITIAL
, &gl
->gl_flags
))
160 gl
->gl_lksb
.sb_lkid
= 0;
161 gfs2_glock_complete(gl
, ret
);
164 static void gdlm_bast(void *arg
, int mode
)
166 struct gfs2_glock
*gl
= arg
;
170 gfs2_glock_cb(gl
, LM_ST_UNLOCKED
);
173 gfs2_glock_cb(gl
, LM_ST_DEFERRED
);
176 gfs2_glock_cb(gl
, LM_ST_SHARED
);
179 pr_err("unknown bast mode %d", mode
);
184 /* convert gfs lock-state to dlm lock-mode */
186 static int make_mode(const unsigned int lmstate
)
191 case LM_ST_EXCLUSIVE
:
198 pr_err("unknown LM state %d", lmstate
);
203 static u32
make_flags(struct gfs2_glock
*gl
, const unsigned int gfs_flags
,
208 if (gl
->gl_lksb
.sb_lvbptr
)
209 lkf
|= DLM_LKF_VALBLK
;
211 if (gfs_flags
& LM_FLAG_TRY
)
212 lkf
|= DLM_LKF_NOQUEUE
;
214 if (gfs_flags
& LM_FLAG_TRY_1CB
) {
215 lkf
|= DLM_LKF_NOQUEUE
;
216 lkf
|= DLM_LKF_NOQUEUEBAST
;
219 if (gfs_flags
& LM_FLAG_PRIORITY
) {
220 lkf
|= DLM_LKF_NOORDER
;
221 lkf
|= DLM_LKF_HEADQUE
;
224 if (gfs_flags
& LM_FLAG_ANY
) {
225 if (req
== DLM_LOCK_PR
)
226 lkf
|= DLM_LKF_ALTCW
;
227 else if (req
== DLM_LOCK_CW
)
228 lkf
|= DLM_LKF_ALTPR
;
233 if (gl
->gl_lksb
.sb_lkid
!= 0) {
234 lkf
|= DLM_LKF_CONVERT
;
235 if (test_bit(GLF_BLOCKING
, &gl
->gl_flags
))
236 lkf
|= DLM_LKF_QUECVT
;
242 static void gfs2_reverse_hex(char *c
, u64 value
)
246 *c
-- = hex_asc
[value
& 0x0f];
251 static int gdlm_lock(struct gfs2_glock
*gl
, unsigned int req_state
,
254 struct lm_lockstruct
*ls
= &gl
->gl_sbd
->sd_lockstruct
;
257 char strname
[GDLM_STRNAME_BYTES
] = "";
259 req
= make_mode(req_state
);
260 lkf
= make_flags(gl
, flags
, req
);
261 gfs2_glstats_inc(gl
, GFS2_LKS_DCOUNT
);
262 gfs2_sbstats_inc(gl
, GFS2_LKS_DCOUNT
);
263 if (gl
->gl_lksb
.sb_lkid
) {
264 gfs2_update_request_times(gl
);
266 memset(strname
, ' ', GDLM_STRNAME_BYTES
- 1);
267 strname
[GDLM_STRNAME_BYTES
- 1] = '\0';
268 gfs2_reverse_hex(strname
+ 7, gl
->gl_name
.ln_type
);
269 gfs2_reverse_hex(strname
+ 23, gl
->gl_name
.ln_number
);
270 gl
->gl_dstamp
= ktime_get_real();
273 * Submit the actual lock request.
276 return dlm_lock(ls
->ls_dlm
, req
, &gl
->gl_lksb
, lkf
, strname
,
277 GDLM_STRNAME_BYTES
- 1, 0, gdlm_ast
, gl
, gdlm_bast
);
280 static void gdlm_put_lock(struct gfs2_glock
*gl
)
282 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
283 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
284 int lvb_needs_unlock
= 0;
287 if (gl
->gl_lksb
.sb_lkid
== 0) {
292 clear_bit(GLF_BLOCKING
, &gl
->gl_flags
);
293 gfs2_glstats_inc(gl
, GFS2_LKS_DCOUNT
);
294 gfs2_sbstats_inc(gl
, GFS2_LKS_DCOUNT
);
295 gfs2_update_request_times(gl
);
297 /* don't want to skip dlm_unlock writing the lvb when lock is ex */
299 if (gl
->gl_lksb
.sb_lvbptr
&& (gl
->gl_state
== LM_ST_EXCLUSIVE
))
300 lvb_needs_unlock
= 1;
302 if (test_bit(SDF_SKIP_DLM_UNLOCK
, &sdp
->sd_flags
) &&
308 error
= dlm_unlock(ls
->ls_dlm
, gl
->gl_lksb
.sb_lkid
, DLM_LKF_VALBLK
,
311 pr_err("gdlm_unlock %x,%llx err=%d\n", gl
->gl_name
.ln_type
,
312 (unsigned long long)gl
->gl_name
.ln_number
, error
);
317 static void gdlm_cancel(struct gfs2_glock
*gl
)
319 struct lm_lockstruct
*ls
= &gl
->gl_sbd
->sd_lockstruct
;
320 dlm_unlock(ls
->ls_dlm
, gl
->gl_lksb
.sb_lkid
, DLM_LKF_CANCEL
, NULL
, gl
);
324 * dlm/gfs2 recovery coordination using dlm_recover callbacks
326 * 1. dlm_controld sees lockspace members change
327 * 2. dlm_controld blocks dlm-kernel locking activity
328 * 3. dlm_controld within dlm-kernel notifies gfs2 (recover_prep)
329 * 4. dlm_controld starts and finishes its own user level recovery
330 * 5. dlm_controld starts dlm-kernel dlm_recoverd to do kernel recovery
331 * 6. dlm_recoverd notifies gfs2 of failed nodes (recover_slot)
332 * 7. dlm_recoverd does its own lock recovery
333 * 8. dlm_recoverd unblocks dlm-kernel locking activity
334 * 9. dlm_recoverd notifies gfs2 when done (recover_done with new generation)
335 * 10. gfs2_control updates control_lock lvb with new generation and jid bits
336 * 11. gfs2_control enqueues journals for gfs2_recover to recover (maybe none)
337 * 12. gfs2_recover dequeues and recovers journals of failed nodes
338 * 13. gfs2_recover provides recovery results to gfs2_control (recovery_result)
339 * 14. gfs2_control updates control_lock lvb jid bits for recovered journals
340 * 15. gfs2_control unblocks normal locking when all journals are recovered
342 * - failures during recovery
344 * recover_prep() may set BLOCK_LOCKS (step 3) again before gfs2_control
345 * clears BLOCK_LOCKS (step 15), e.g. another node fails while still
346 * recovering for a prior failure. gfs2_control needs a way to detect
347 * this so it can leave BLOCK_LOCKS set in step 15. This is managed using
348 * the recover_block and recover_start values.
350 * recover_done() provides a new lockspace generation number each time it
351 * is called (step 9). This generation number is saved as recover_start.
352 * When recover_prep() is called, it sets BLOCK_LOCKS and sets
353 * recover_block = recover_start. So, while recover_block is equal to
354 * recover_start, BLOCK_LOCKS should remain set. (recover_spin must
355 * be held around the BLOCK_LOCKS/recover_block/recover_start logic.)
357 * - more specific gfs2 steps in sequence above
359 * 3. recover_prep sets BLOCK_LOCKS and sets recover_block = recover_start
360 * 6. recover_slot records any failed jids (maybe none)
361 * 9. recover_done sets recover_start = new generation number
362 * 10. gfs2_control sets control_lock lvb = new gen + bits for failed jids
363 * 12. gfs2_recover does journal recoveries for failed jids identified above
364 * 14. gfs2_control clears control_lock lvb bits for recovered jids
365 * 15. gfs2_control checks if recover_block == recover_start (step 3 occured
366 * again) then do nothing, otherwise if recover_start > recover_block
367 * then clear BLOCK_LOCKS.
369 * - parallel recovery steps across all nodes
371 * All nodes attempt to update the control_lock lvb with the new generation
372 * number and jid bits, but only the first to get the control_lock EX will
373 * do so; others will see that it's already done (lvb already contains new
374 * generation number.)
376 * . All nodes get the same recover_prep/recover_slot/recover_done callbacks
377 * . All nodes attempt to set control_lock lvb gen + bits for the new gen
378 * . One node gets control_lock first and writes the lvb, others see it's done
379 * . All nodes attempt to recover jids for which they see control_lock bits set
380 * . One node succeeds for a jid, and that one clears the jid bit in the lvb
381 * . All nodes will eventually see all lvb bits clear and unblock locks
383 * - is there a problem with clearing an lvb bit that should be set
384 * and missing a journal recovery?
387 * 2. lvb bit set for step 1
388 * 3. jid recovered for step 1
389 * 4. jid taken again (new mount)
390 * 5. jid fails (for step 4)
391 * 6. lvb bit set for step 5 (will already be set)
392 * 7. lvb bit cleared for step 3
394 * This is not a problem because the failure in step 5 does not
395 * require recovery, because the mount in step 4 could not have
396 * progressed far enough to unblock locks and access the fs. The
397 * control_mount() function waits for all recoveries to be complete
398 * for the latest lockspace generation before ever unblocking locks
399 * and returning. The mount in step 4 waits until the recovery in
402 * - special case of first mounter: first node to mount the fs
404 * The first node to mount a gfs2 fs needs to check all the journals
405 * and recover any that need recovery before other nodes are allowed
406 * to mount the fs. (Others may begin mounting, but they must wait
407 * for the first mounter to be done before taking locks on the fs
408 * or accessing the fs.) This has two parts:
410 * 1. The mounted_lock tells a node it's the first to mount the fs.
411 * Each node holds the mounted_lock in PR while it's mounted.
412 * Each node tries to acquire the mounted_lock in EX when it mounts.
413 * If a node is granted the mounted_lock EX it means there are no
414 * other mounted nodes (no PR locks exist), and it is the first mounter.
415 * The mounted_lock is demoted to PR when first recovery is done, so
416 * others will fail to get an EX lock, but will get a PR lock.
418 * 2. The control_lock blocks others in control_mount() while the first
419 * mounter is doing first mount recovery of all journals.
420 * A mounting node needs to acquire control_lock in EX mode before
421 * it can proceed. The first mounter holds control_lock in EX while doing
422 * the first mount recovery, blocking mounts from other nodes, then demotes
423 * control_lock to NL when it's done (others_may_mount/first_done),
424 * allowing other nodes to continue mounting.
427 * control_lock EX/NOQUEUE success
428 * mounted_lock EX/NOQUEUE success (no other PR, so no other mounters)
430 * do first mounter recovery
431 * mounted_lock EX->PR
432 * control_lock EX->NL, write lvb generation
435 * control_lock EX/NOQUEUE success (if fail -EAGAIN, retry)
436 * mounted_lock EX/NOQUEUE fail -EAGAIN (expected due to other mounters PR)
437 * mounted_lock PR/NOQUEUE success
438 * read lvb generation
439 * control_lock EX->NL
442 * - mount during recovery
444 * If a node mounts while others are doing recovery (not first mounter),
445 * the mounting node will get its initial recover_done() callback without
446 * having seen any previous failures/callbacks.
448 * It must wait for all recoveries preceding its mount to be finished
449 * before it unblocks locks. It does this by repeating the "other mounter"
450 * steps above until the lvb generation number is >= its mount generation
451 * number (from initial recover_done) and all lvb bits are clear.
453 * - control_lock lvb format
455 * 4 bytes generation number: the latest dlm lockspace generation number
456 * from recover_done callback. Indicates the jid bitmap has been updated
457 * to reflect all slot failures through that generation.
459 * GDLM_LVB_SIZE-8 bytes of jid bit map. If bit N is set, it indicates
460 * that jid N needs recovery.
463 #define JID_BITMAP_OFFSET 8 /* 4 byte generation number + 4 byte unused */
465 static void control_lvb_read(struct lm_lockstruct
*ls
, uint32_t *lvb_gen
,
469 memcpy(lvb_bits
, ls
->ls_control_lvb
, GDLM_LVB_SIZE
);
470 memcpy(&gen
, lvb_bits
, sizeof(__le32
));
471 *lvb_gen
= le32_to_cpu(gen
);
474 static void control_lvb_write(struct lm_lockstruct
*ls
, uint32_t lvb_gen
,
478 memcpy(ls
->ls_control_lvb
, lvb_bits
, GDLM_LVB_SIZE
);
479 gen
= cpu_to_le32(lvb_gen
);
480 memcpy(ls
->ls_control_lvb
, &gen
, sizeof(__le32
));
483 static int all_jid_bits_clear(char *lvb
)
485 return !memchr_inv(lvb
+ JID_BITMAP_OFFSET
, 0,
486 GDLM_LVB_SIZE
- JID_BITMAP_OFFSET
);
489 static void sync_wait_cb(void *arg
)
491 struct lm_lockstruct
*ls
= arg
;
492 complete(&ls
->ls_sync_wait
);
495 static int sync_unlock(struct gfs2_sbd
*sdp
, struct dlm_lksb
*lksb
, char *name
)
497 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
500 error
= dlm_unlock(ls
->ls_dlm
, lksb
->sb_lkid
, 0, lksb
, ls
);
502 fs_err(sdp
, "%s lkid %x error %d\n",
503 name
, lksb
->sb_lkid
, error
);
507 wait_for_completion(&ls
->ls_sync_wait
);
509 if (lksb
->sb_status
!= -DLM_EUNLOCK
) {
510 fs_err(sdp
, "%s lkid %x status %d\n",
511 name
, lksb
->sb_lkid
, lksb
->sb_status
);
517 static int sync_lock(struct gfs2_sbd
*sdp
, int mode
, uint32_t flags
,
518 unsigned int num
, struct dlm_lksb
*lksb
, char *name
)
520 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
521 char strname
[GDLM_STRNAME_BYTES
];
524 memset(strname
, 0, GDLM_STRNAME_BYTES
);
525 snprintf(strname
, GDLM_STRNAME_BYTES
, "%8x%16x", LM_TYPE_NONDISK
, num
);
527 error
= dlm_lock(ls
->ls_dlm
, mode
, lksb
, flags
,
528 strname
, GDLM_STRNAME_BYTES
- 1,
529 0, sync_wait_cb
, ls
, NULL
);
531 fs_err(sdp
, "%s lkid %x flags %x mode %d error %d\n",
532 name
, lksb
->sb_lkid
, flags
, mode
, error
);
536 wait_for_completion(&ls
->ls_sync_wait
);
538 status
= lksb
->sb_status
;
540 if (status
&& status
!= -EAGAIN
) {
541 fs_err(sdp
, "%s lkid %x flags %x mode %d status %d\n",
542 name
, lksb
->sb_lkid
, flags
, mode
, status
);
548 static int mounted_unlock(struct gfs2_sbd
*sdp
)
550 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
551 return sync_unlock(sdp
, &ls
->ls_mounted_lksb
, "mounted_lock");
554 static int mounted_lock(struct gfs2_sbd
*sdp
, int mode
, uint32_t flags
)
556 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
557 return sync_lock(sdp
, mode
, flags
, GFS2_MOUNTED_LOCK
,
558 &ls
->ls_mounted_lksb
, "mounted_lock");
561 static int control_unlock(struct gfs2_sbd
*sdp
)
563 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
564 return sync_unlock(sdp
, &ls
->ls_control_lksb
, "control_lock");
567 static int control_lock(struct gfs2_sbd
*sdp
, int mode
, uint32_t flags
)
569 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
570 return sync_lock(sdp
, mode
, flags
, GFS2_CONTROL_LOCK
,
571 &ls
->ls_control_lksb
, "control_lock");
574 static void gfs2_control_func(struct work_struct
*work
)
576 struct gfs2_sbd
*sdp
= container_of(work
, struct gfs2_sbd
, sd_control_work
.work
);
577 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
578 uint32_t block_gen
, start_gen
, lvb_gen
, flags
;
584 spin_lock(&ls
->ls_recover_spin
);
586 * No MOUNT_DONE means we're still mounting; control_mount()
587 * will set this flag, after which this thread will take over
588 * all further clearing of BLOCK_LOCKS.
590 * FIRST_MOUNT means this node is doing first mounter recovery,
591 * for which recovery control is handled by
592 * control_mount()/control_first_done(), not this thread.
594 if (!test_bit(DFL_MOUNT_DONE
, &ls
->ls_recover_flags
) ||
595 test_bit(DFL_FIRST_MOUNT
, &ls
->ls_recover_flags
)) {
596 spin_unlock(&ls
->ls_recover_spin
);
599 block_gen
= ls
->ls_recover_block
;
600 start_gen
= ls
->ls_recover_start
;
601 spin_unlock(&ls
->ls_recover_spin
);
604 * Equal block_gen and start_gen implies we are between
605 * recover_prep and recover_done callbacks, which means
606 * dlm recovery is in progress and dlm locking is blocked.
607 * There's no point trying to do any work until recover_done.
610 if (block_gen
== start_gen
)
614 * Propagate recover_submit[] and recover_result[] to lvb:
615 * dlm_recoverd adds to recover_submit[] jids needing recovery
616 * gfs2_recover adds to recover_result[] journal recovery results
618 * set lvb bit for jids in recover_submit[] if the lvb has not
619 * yet been updated for the generation of the failure
621 * clear lvb bit for jids in recover_result[] if the result of
622 * the journal recovery is SUCCESS
625 error
= control_lock(sdp
, DLM_LOCK_EX
, DLM_LKF_CONVERT
|DLM_LKF_VALBLK
);
627 fs_err(sdp
, "control lock EX error %d\n", error
);
631 control_lvb_read(ls
, &lvb_gen
, ls
->ls_lvb_bits
);
633 spin_lock(&ls
->ls_recover_spin
);
634 if (block_gen
!= ls
->ls_recover_block
||
635 start_gen
!= ls
->ls_recover_start
) {
636 fs_info(sdp
, "recover generation %u block1 %u %u\n",
637 start_gen
, block_gen
, ls
->ls_recover_block
);
638 spin_unlock(&ls
->ls_recover_spin
);
639 control_lock(sdp
, DLM_LOCK_NL
, DLM_LKF_CONVERT
);
643 recover_size
= ls
->ls_recover_size
;
645 if (lvb_gen
<= start_gen
) {
647 * Clear lvb bits for jids we've successfully recovered.
648 * Because all nodes attempt to recover failed journals,
649 * a journal can be recovered multiple times successfully
650 * in succession. Only the first will really do recovery,
651 * the others find it clean, but still report a successful
652 * recovery. So, another node may have already recovered
653 * the jid and cleared the lvb bit for it.
655 for (i
= 0; i
< recover_size
; i
++) {
656 if (ls
->ls_recover_result
[i
] != LM_RD_SUCCESS
)
659 ls
->ls_recover_result
[i
] = 0;
661 if (!test_bit_le(i
, ls
->ls_lvb_bits
+ JID_BITMAP_OFFSET
))
664 __clear_bit_le(i
, ls
->ls_lvb_bits
+ JID_BITMAP_OFFSET
);
669 if (lvb_gen
== start_gen
) {
671 * Failed slots before start_gen are already set in lvb.
673 for (i
= 0; i
< recover_size
; i
++) {
674 if (!ls
->ls_recover_submit
[i
])
676 if (ls
->ls_recover_submit
[i
] < lvb_gen
)
677 ls
->ls_recover_submit
[i
] = 0;
679 } else if (lvb_gen
< start_gen
) {
681 * Failed slots before start_gen are not yet set in lvb.
683 for (i
= 0; i
< recover_size
; i
++) {
684 if (!ls
->ls_recover_submit
[i
])
686 if (ls
->ls_recover_submit
[i
] < start_gen
) {
687 ls
->ls_recover_submit
[i
] = 0;
688 __set_bit_le(i
, ls
->ls_lvb_bits
+ JID_BITMAP_OFFSET
);
691 /* even if there are no bits to set, we need to write the
692 latest generation to the lvb */
696 * we should be getting a recover_done() for lvb_gen soon
699 spin_unlock(&ls
->ls_recover_spin
);
702 control_lvb_write(ls
, start_gen
, ls
->ls_lvb_bits
);
703 flags
= DLM_LKF_CONVERT
| DLM_LKF_VALBLK
;
705 flags
= DLM_LKF_CONVERT
;
708 error
= control_lock(sdp
, DLM_LOCK_NL
, flags
);
710 fs_err(sdp
, "control lock NL error %d\n", error
);
715 * Everyone will see jid bits set in the lvb, run gfs2_recover_set(),
716 * and clear a jid bit in the lvb if the recovery is a success.
717 * Eventually all journals will be recovered, all jid bits will
718 * be cleared in the lvb, and everyone will clear BLOCK_LOCKS.
721 for (i
= 0; i
< recover_size
; i
++) {
722 if (test_bit_le(i
, ls
->ls_lvb_bits
+ JID_BITMAP_OFFSET
)) {
723 fs_info(sdp
, "recover generation %u jid %d\n",
725 gfs2_recover_set(sdp
, i
);
733 * No more jid bits set in lvb, all recovery is done, unblock locks
734 * (unless a new recover_prep callback has occured blocking locks
735 * again while working above)
738 spin_lock(&ls
->ls_recover_spin
);
739 if (ls
->ls_recover_block
== block_gen
&&
740 ls
->ls_recover_start
== start_gen
) {
741 clear_bit(DFL_BLOCK_LOCKS
, &ls
->ls_recover_flags
);
742 spin_unlock(&ls
->ls_recover_spin
);
743 fs_info(sdp
, "recover generation %u done\n", start_gen
);
744 gfs2_glock_thaw(sdp
);
746 fs_info(sdp
, "recover generation %u block2 %u %u\n",
747 start_gen
, block_gen
, ls
->ls_recover_block
);
748 spin_unlock(&ls
->ls_recover_spin
);
752 static int control_mount(struct gfs2_sbd
*sdp
)
754 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
755 uint32_t start_gen
, block_gen
, mount_gen
, lvb_gen
;
760 memset(&ls
->ls_mounted_lksb
, 0, sizeof(struct dlm_lksb
));
761 memset(&ls
->ls_control_lksb
, 0, sizeof(struct dlm_lksb
));
762 memset(&ls
->ls_control_lvb
, 0, GDLM_LVB_SIZE
);
763 ls
->ls_control_lksb
.sb_lvbptr
= ls
->ls_control_lvb
;
764 init_completion(&ls
->ls_sync_wait
);
766 set_bit(DFL_BLOCK_LOCKS
, &ls
->ls_recover_flags
);
768 error
= control_lock(sdp
, DLM_LOCK_NL
, DLM_LKF_VALBLK
);
770 fs_err(sdp
, "control_mount control_lock NL error %d\n", error
);
774 error
= mounted_lock(sdp
, DLM_LOCK_NL
, 0);
776 fs_err(sdp
, "control_mount mounted_lock NL error %d\n", error
);
780 mounted_mode
= DLM_LOCK_NL
;
783 if (retries
++ && signal_pending(current
)) {
789 * We always start with both locks in NL. control_lock is
790 * demoted to NL below so we don't need to do it here.
793 if (mounted_mode
!= DLM_LOCK_NL
) {
794 error
= mounted_lock(sdp
, DLM_LOCK_NL
, DLM_LKF_CONVERT
);
797 mounted_mode
= DLM_LOCK_NL
;
801 * Other nodes need to do some work in dlm recovery and gfs2_control
802 * before the recover_done and control_lock will be ready for us below.
803 * A delay here is not required but often avoids having to retry.
806 msleep_interruptible(500);
809 * Acquire control_lock in EX and mounted_lock in either EX or PR.
810 * control_lock lvb keeps track of any pending journal recoveries.
811 * mounted_lock indicates if any other nodes have the fs mounted.
814 error
= control_lock(sdp
, DLM_LOCK_EX
, DLM_LKF_CONVERT
|DLM_LKF_NOQUEUE
|DLM_LKF_VALBLK
);
815 if (error
== -EAGAIN
) {
818 fs_err(sdp
, "control_mount control_lock EX error %d\n", error
);
822 error
= mounted_lock(sdp
, DLM_LOCK_EX
, DLM_LKF_CONVERT
|DLM_LKF_NOQUEUE
);
824 mounted_mode
= DLM_LOCK_EX
;
826 } else if (error
!= -EAGAIN
) {
827 fs_err(sdp
, "control_mount mounted_lock EX error %d\n", error
);
831 error
= mounted_lock(sdp
, DLM_LOCK_PR
, DLM_LKF_CONVERT
|DLM_LKF_NOQUEUE
);
833 mounted_mode
= DLM_LOCK_PR
;
836 /* not even -EAGAIN should happen here */
837 fs_err(sdp
, "control_mount mounted_lock PR error %d\n", error
);
843 * If we got both locks above in EX, then we're the first mounter.
844 * If not, then we need to wait for the control_lock lvb to be
845 * updated by other mounted nodes to reflect our mount generation.
847 * In simple first mounter cases, first mounter will see zero lvb_gen,
848 * but in cases where all existing nodes leave/fail before mounting
849 * nodes finish control_mount, then all nodes will be mounting and
850 * lvb_gen will be non-zero.
853 control_lvb_read(ls
, &lvb_gen
, ls
->ls_lvb_bits
);
855 if (lvb_gen
== 0xFFFFFFFF) {
856 /* special value to force mount attempts to fail */
857 fs_err(sdp
, "control_mount control_lock disabled\n");
862 if (mounted_mode
== DLM_LOCK_EX
) {
863 /* first mounter, keep both EX while doing first recovery */
864 spin_lock(&ls
->ls_recover_spin
);
865 clear_bit(DFL_BLOCK_LOCKS
, &ls
->ls_recover_flags
);
866 set_bit(DFL_MOUNT_DONE
, &ls
->ls_recover_flags
);
867 set_bit(DFL_FIRST_MOUNT
, &ls
->ls_recover_flags
);
868 spin_unlock(&ls
->ls_recover_spin
);
869 fs_info(sdp
, "first mounter control generation %u\n", lvb_gen
);
873 error
= control_lock(sdp
, DLM_LOCK_NL
, DLM_LKF_CONVERT
);
878 * We are not first mounter, now we need to wait for the control_lock
879 * lvb generation to be >= the generation from our first recover_done
880 * and all lvb bits to be clear (no pending journal recoveries.)
883 if (!all_jid_bits_clear(ls
->ls_lvb_bits
)) {
884 /* journals need recovery, wait until all are clear */
885 fs_info(sdp
, "control_mount wait for journal recovery\n");
889 spin_lock(&ls
->ls_recover_spin
);
890 block_gen
= ls
->ls_recover_block
;
891 start_gen
= ls
->ls_recover_start
;
892 mount_gen
= ls
->ls_recover_mount
;
894 if (lvb_gen
< mount_gen
) {
895 /* wait for mounted nodes to update control_lock lvb to our
896 generation, which might include new recovery bits set */
897 fs_info(sdp
, "control_mount wait1 block %u start %u mount %u "
898 "lvb %u flags %lx\n", block_gen
, start_gen
, mount_gen
,
899 lvb_gen
, ls
->ls_recover_flags
);
900 spin_unlock(&ls
->ls_recover_spin
);
904 if (lvb_gen
!= start_gen
) {
905 /* wait for mounted nodes to update control_lock lvb to the
906 latest recovery generation */
907 fs_info(sdp
, "control_mount wait2 block %u start %u mount %u "
908 "lvb %u flags %lx\n", block_gen
, start_gen
, mount_gen
,
909 lvb_gen
, ls
->ls_recover_flags
);
910 spin_unlock(&ls
->ls_recover_spin
);
914 if (block_gen
== start_gen
) {
915 /* dlm recovery in progress, wait for it to finish */
916 fs_info(sdp
, "control_mount wait3 block %u start %u mount %u "
917 "lvb %u flags %lx\n", block_gen
, start_gen
, mount_gen
,
918 lvb_gen
, ls
->ls_recover_flags
);
919 spin_unlock(&ls
->ls_recover_spin
);
923 clear_bit(DFL_BLOCK_LOCKS
, &ls
->ls_recover_flags
);
924 set_bit(DFL_MOUNT_DONE
, &ls
->ls_recover_flags
);
925 memset(ls
->ls_recover_submit
, 0, ls
->ls_recover_size
*sizeof(uint32_t));
926 memset(ls
->ls_recover_result
, 0, ls
->ls_recover_size
*sizeof(uint32_t));
927 spin_unlock(&ls
->ls_recover_spin
);
936 static int dlm_recovery_wait(void *word
)
942 static int control_first_done(struct gfs2_sbd
*sdp
)
944 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
945 uint32_t start_gen
, block_gen
;
949 spin_lock(&ls
->ls_recover_spin
);
950 start_gen
= ls
->ls_recover_start
;
951 block_gen
= ls
->ls_recover_block
;
953 if (test_bit(DFL_BLOCK_LOCKS
, &ls
->ls_recover_flags
) ||
954 !test_bit(DFL_MOUNT_DONE
, &ls
->ls_recover_flags
) ||
955 !test_bit(DFL_FIRST_MOUNT
, &ls
->ls_recover_flags
)) {
956 /* sanity check, should not happen */
957 fs_err(sdp
, "control_first_done start %u block %u flags %lx\n",
958 start_gen
, block_gen
, ls
->ls_recover_flags
);
959 spin_unlock(&ls
->ls_recover_spin
);
964 if (start_gen
== block_gen
) {
966 * Wait for the end of a dlm recovery cycle to switch from
967 * first mounter recovery. We can ignore any recover_slot
968 * callbacks between the recover_prep and next recover_done
969 * because we are still the first mounter and any failed nodes
970 * have not fully mounted, so they don't need recovery.
972 spin_unlock(&ls
->ls_recover_spin
);
973 fs_info(sdp
, "control_first_done wait gen %u\n", start_gen
);
975 wait_on_bit(&ls
->ls_recover_flags
, DFL_DLM_RECOVERY
,
976 dlm_recovery_wait
, TASK_UNINTERRUPTIBLE
);
980 clear_bit(DFL_FIRST_MOUNT
, &ls
->ls_recover_flags
);
981 set_bit(DFL_FIRST_MOUNT_DONE
, &ls
->ls_recover_flags
);
982 memset(ls
->ls_recover_submit
, 0, ls
->ls_recover_size
*sizeof(uint32_t));
983 memset(ls
->ls_recover_result
, 0, ls
->ls_recover_size
*sizeof(uint32_t));
984 spin_unlock(&ls
->ls_recover_spin
);
986 memset(ls
->ls_lvb_bits
, 0, GDLM_LVB_SIZE
);
987 control_lvb_write(ls
, start_gen
, ls
->ls_lvb_bits
);
989 error
= mounted_lock(sdp
, DLM_LOCK_PR
, DLM_LKF_CONVERT
);
991 fs_err(sdp
, "control_first_done mounted PR error %d\n", error
);
993 error
= control_lock(sdp
, DLM_LOCK_NL
, DLM_LKF_CONVERT
|DLM_LKF_VALBLK
);
995 fs_err(sdp
, "control_first_done control NL error %d\n", error
);
1001 * Expand static jid arrays if necessary (by increments of RECOVER_SIZE_INC)
1002 * to accomodate the largest slot number. (NB dlm slot numbers start at 1,
1003 * gfs2 jids start at 0, so jid = slot - 1)
1006 #define RECOVER_SIZE_INC 16
1008 static int set_recover_size(struct gfs2_sbd
*sdp
, struct dlm_slot
*slots
,
1011 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1012 uint32_t *submit
= NULL
;
1013 uint32_t *result
= NULL
;
1014 uint32_t old_size
, new_size
;
1017 if (!ls
->ls_lvb_bits
) {
1018 ls
->ls_lvb_bits
= kzalloc(GDLM_LVB_SIZE
, GFP_NOFS
);
1019 if (!ls
->ls_lvb_bits
)
1024 for (i
= 0; i
< num_slots
; i
++) {
1025 if (max_jid
< slots
[i
].slot
- 1)
1026 max_jid
= slots
[i
].slot
- 1;
1029 old_size
= ls
->ls_recover_size
;
1031 if (old_size
>= max_jid
+ 1)
1034 new_size
= old_size
+ RECOVER_SIZE_INC
;
1036 submit
= kzalloc(new_size
* sizeof(uint32_t), GFP_NOFS
);
1037 result
= kzalloc(new_size
* sizeof(uint32_t), GFP_NOFS
);
1038 if (!submit
|| !result
) {
1044 spin_lock(&ls
->ls_recover_spin
);
1045 memcpy(submit
, ls
->ls_recover_submit
, old_size
* sizeof(uint32_t));
1046 memcpy(result
, ls
->ls_recover_result
, old_size
* sizeof(uint32_t));
1047 kfree(ls
->ls_recover_submit
);
1048 kfree(ls
->ls_recover_result
);
1049 ls
->ls_recover_submit
= submit
;
1050 ls
->ls_recover_result
= result
;
1051 ls
->ls_recover_size
= new_size
;
1052 spin_unlock(&ls
->ls_recover_spin
);
1056 static void free_recover_size(struct lm_lockstruct
*ls
)
1058 kfree(ls
->ls_lvb_bits
);
1059 kfree(ls
->ls_recover_submit
);
1060 kfree(ls
->ls_recover_result
);
1061 ls
->ls_recover_submit
= NULL
;
1062 ls
->ls_recover_result
= NULL
;
1063 ls
->ls_recover_size
= 0;
1066 /* dlm calls before it does lock recovery */
1068 static void gdlm_recover_prep(void *arg
)
1070 struct gfs2_sbd
*sdp
= arg
;
1071 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1073 spin_lock(&ls
->ls_recover_spin
);
1074 ls
->ls_recover_block
= ls
->ls_recover_start
;
1075 set_bit(DFL_DLM_RECOVERY
, &ls
->ls_recover_flags
);
1077 if (!test_bit(DFL_MOUNT_DONE
, &ls
->ls_recover_flags
) ||
1078 test_bit(DFL_FIRST_MOUNT
, &ls
->ls_recover_flags
)) {
1079 spin_unlock(&ls
->ls_recover_spin
);
1082 set_bit(DFL_BLOCK_LOCKS
, &ls
->ls_recover_flags
);
1083 spin_unlock(&ls
->ls_recover_spin
);
1086 /* dlm calls after recover_prep has been completed on all lockspace members;
1087 identifies slot/jid of failed member */
1089 static void gdlm_recover_slot(void *arg
, struct dlm_slot
*slot
)
1091 struct gfs2_sbd
*sdp
= arg
;
1092 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1093 int jid
= slot
->slot
- 1;
1095 spin_lock(&ls
->ls_recover_spin
);
1096 if (ls
->ls_recover_size
< jid
+ 1) {
1097 fs_err(sdp
, "recover_slot jid %d gen %u short size %d",
1098 jid
, ls
->ls_recover_block
, ls
->ls_recover_size
);
1099 spin_unlock(&ls
->ls_recover_spin
);
1103 if (ls
->ls_recover_submit
[jid
]) {
1104 fs_info(sdp
, "recover_slot jid %d gen %u prev %u\n",
1105 jid
, ls
->ls_recover_block
, ls
->ls_recover_submit
[jid
]);
1107 ls
->ls_recover_submit
[jid
] = ls
->ls_recover_block
;
1108 spin_unlock(&ls
->ls_recover_spin
);
1111 /* dlm calls after recover_slot and after it completes lock recovery */
1113 static void gdlm_recover_done(void *arg
, struct dlm_slot
*slots
, int num_slots
,
1114 int our_slot
, uint32_t generation
)
1116 struct gfs2_sbd
*sdp
= arg
;
1117 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1119 /* ensure the ls jid arrays are large enough */
1120 set_recover_size(sdp
, slots
, num_slots
);
1122 spin_lock(&ls
->ls_recover_spin
);
1123 ls
->ls_recover_start
= generation
;
1125 if (!ls
->ls_recover_mount
) {
1126 ls
->ls_recover_mount
= generation
;
1127 ls
->ls_jid
= our_slot
- 1;
1130 if (!test_bit(DFL_UNMOUNT
, &ls
->ls_recover_flags
))
1131 queue_delayed_work(gfs2_control_wq
, &sdp
->sd_control_work
, 0);
1133 clear_bit(DFL_DLM_RECOVERY
, &ls
->ls_recover_flags
);
1134 smp_mb__after_clear_bit();
1135 wake_up_bit(&ls
->ls_recover_flags
, DFL_DLM_RECOVERY
);
1136 spin_unlock(&ls
->ls_recover_spin
);
1139 /* gfs2_recover thread has a journal recovery result */
1141 static void gdlm_recovery_result(struct gfs2_sbd
*sdp
, unsigned int jid
,
1142 unsigned int result
)
1144 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1146 if (test_bit(DFL_NO_DLM_OPS
, &ls
->ls_recover_flags
))
1149 /* don't care about the recovery of own journal during mount */
1150 if (jid
== ls
->ls_jid
)
1153 spin_lock(&ls
->ls_recover_spin
);
1154 if (test_bit(DFL_FIRST_MOUNT
, &ls
->ls_recover_flags
)) {
1155 spin_unlock(&ls
->ls_recover_spin
);
1158 if (ls
->ls_recover_size
< jid
+ 1) {
1159 fs_err(sdp
, "recovery_result jid %d short size %d",
1160 jid
, ls
->ls_recover_size
);
1161 spin_unlock(&ls
->ls_recover_spin
);
1165 fs_info(sdp
, "recover jid %d result %s\n", jid
,
1166 result
== LM_RD_GAVEUP
? "busy" : "success");
1168 ls
->ls_recover_result
[jid
] = result
;
1170 /* GAVEUP means another node is recovering the journal; delay our
1171 next attempt to recover it, to give the other node a chance to
1172 finish before trying again */
1174 if (!test_bit(DFL_UNMOUNT
, &ls
->ls_recover_flags
))
1175 queue_delayed_work(gfs2_control_wq
, &sdp
->sd_control_work
,
1176 result
== LM_RD_GAVEUP
? HZ
: 0);
1177 spin_unlock(&ls
->ls_recover_spin
);
1180 const struct dlm_lockspace_ops gdlm_lockspace_ops
= {
1181 .recover_prep
= gdlm_recover_prep
,
1182 .recover_slot
= gdlm_recover_slot
,
1183 .recover_done
= gdlm_recover_done
,
1186 static int gdlm_mount(struct gfs2_sbd
*sdp
, const char *table
)
1188 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1189 char cluster
[GFS2_LOCKNAME_LEN
];
1192 int error
, ops_result
;
1195 * initialize everything
1198 INIT_DELAYED_WORK(&sdp
->sd_control_work
, gfs2_control_func
);
1199 spin_lock_init(&ls
->ls_recover_spin
);
1200 ls
->ls_recover_flags
= 0;
1201 ls
->ls_recover_mount
= 0;
1202 ls
->ls_recover_start
= 0;
1203 ls
->ls_recover_block
= 0;
1204 ls
->ls_recover_size
= 0;
1205 ls
->ls_recover_submit
= NULL
;
1206 ls
->ls_recover_result
= NULL
;
1207 ls
->ls_lvb_bits
= NULL
;
1209 error
= set_recover_size(sdp
, NULL
, 0);
1214 * prepare dlm_new_lockspace args
1217 fsname
= strchr(table
, ':');
1219 fs_info(sdp
, "no fsname found\n");
1223 memset(cluster
, 0, sizeof(cluster
));
1224 memcpy(cluster
, table
, strlen(table
) - strlen(fsname
));
1227 flags
= DLM_LSFL_FS
| DLM_LSFL_NEWEXCL
;
1230 * create/join lockspace
1233 error
= dlm_new_lockspace(fsname
, cluster
, flags
, GDLM_LVB_SIZE
,
1234 &gdlm_lockspace_ops
, sdp
, &ops_result
,
1237 fs_err(sdp
, "dlm_new_lockspace error %d\n", error
);
1241 if (ops_result
< 0) {
1243 * dlm does not support ops callbacks,
1244 * old dlm_controld/gfs_controld are used, try without ops.
1246 fs_info(sdp
, "dlm lockspace ops not used\n");
1247 free_recover_size(ls
);
1248 set_bit(DFL_NO_DLM_OPS
, &ls
->ls_recover_flags
);
1252 if (!test_bit(SDF_NOJOURNALID
, &sdp
->sd_flags
)) {
1253 fs_err(sdp
, "dlm lockspace ops disallow jid preset\n");
1259 * control_mount() uses control_lock to determine first mounter,
1260 * and for later mounts, waits for any recoveries to be cleared.
1263 error
= control_mount(sdp
);
1265 fs_err(sdp
, "mount control error %d\n", error
);
1269 ls
->ls_first
= !!test_bit(DFL_FIRST_MOUNT
, &ls
->ls_recover_flags
);
1270 clear_bit(SDF_NOJOURNALID
, &sdp
->sd_flags
);
1271 smp_mb__after_clear_bit();
1272 wake_up_bit(&sdp
->sd_flags
, SDF_NOJOURNALID
);
1276 dlm_release_lockspace(ls
->ls_dlm
, 2);
1278 free_recover_size(ls
);
1283 static void gdlm_first_done(struct gfs2_sbd
*sdp
)
1285 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1288 if (test_bit(DFL_NO_DLM_OPS
, &ls
->ls_recover_flags
))
1291 error
= control_first_done(sdp
);
1293 fs_err(sdp
, "mount first_done error %d\n", error
);
1296 static void gdlm_unmount(struct gfs2_sbd
*sdp
)
1298 struct lm_lockstruct
*ls
= &sdp
->sd_lockstruct
;
1300 if (test_bit(DFL_NO_DLM_OPS
, &ls
->ls_recover_flags
))
1303 /* wait for gfs2_control_wq to be done with this mount */
1305 spin_lock(&ls
->ls_recover_spin
);
1306 set_bit(DFL_UNMOUNT
, &ls
->ls_recover_flags
);
1307 spin_unlock(&ls
->ls_recover_spin
);
1308 flush_delayed_work(&sdp
->sd_control_work
);
1310 /* mounted_lock and control_lock will be purged in dlm recovery */
1313 dlm_release_lockspace(ls
->ls_dlm
, 2);
1317 free_recover_size(ls
);
1320 static const match_table_t dlm_tokens
= {
1321 { Opt_jid
, "jid=%d"},
1323 { Opt_first
, "first=%d"},
1324 { Opt_nodir
, "nodir=%d"},
1328 const struct lm_lockops gfs2_dlm_ops
= {
1329 .lm_proto_name
= "lock_dlm",
1330 .lm_mount
= gdlm_mount
,
1331 .lm_first_done
= gdlm_first_done
,
1332 .lm_recovery_result
= gdlm_recovery_result
,
1333 .lm_unmount
= gdlm_unmount
,
1334 .lm_put_lock
= gdlm_put_lock
,
1335 .lm_lock
= gdlm_lock
,
1336 .lm_cancel
= gdlm_cancel
,
1337 .lm_tokens
= &dlm_tokens
,