4 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
6 Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
7 Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
8 Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
10 drbd is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2, or (at your option)
15 drbd is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with drbd; see the file COPYING. If not, write to
22 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
26 #include <linux/slab.h>
27 #include <linux/drbd.h>
29 #include "drbd_wrappers.h"
31 /* We maintain a trivial check sum in our on disk activity log.
32 * With that we can ensure correct operation even when the storage
33 * device might do a partial (last) sector write while loosing power.
35 struct __packed al_transaction
{
40 u32 extent
; } updates
[1 + AL_EXTENTS_PT
];
44 struct update_odbm_work
{
49 struct update_al_work
{
51 struct lc_element
*al_ext
;
52 struct completion event
;
54 /* if old_enr != LC_FREE, write corresponding bitmap sector, too */
58 struct drbd_atodb_wait
{
60 struct completion io_done
;
61 struct drbd_conf
*mdev
;
66 int w_al_write_transaction(struct drbd_conf
*, struct drbd_work
*, int);
68 static int _drbd_md_sync_page_io(struct drbd_conf
*mdev
,
69 struct drbd_backing_dev
*bdev
,
70 struct page
*page
, sector_t sector
,
74 struct drbd_md_io md_io
;
78 init_completion(&md_io
.event
);
81 if ((rw
& WRITE
) && !test_bit(MD_NO_BARRIER
, &mdev
->flags
))
82 rw
|= (1 << BIO_RW_BARRIER
);
83 rw
|= ((1<<BIO_RW_UNPLUG
) | (1<<BIO_RW_SYNCIO
));
86 bio
= bio_alloc(GFP_NOIO
, 1);
87 bio
->bi_bdev
= bdev
->md_bdev
;
88 bio
->bi_sector
= sector
;
89 ok
= (bio_add_page(bio
, page
, size
, 0) == size
);
92 bio
->bi_private
= &md_io
;
93 bio
->bi_end_io
= drbd_md_io_complete
;
96 if (FAULT_ACTIVE(mdev
, (rw
& WRITE
) ? DRBD_FAULT_MD_WR
: DRBD_FAULT_MD_RD
))
100 wait_for_completion(&md_io
.event
);
101 ok
= bio_flagged(bio
, BIO_UPTODATE
) && md_io
.error
== 0;
103 /* check for unsupported barrier op.
104 * would rather check on EOPNOTSUPP, but that is not reliable.
105 * don't try again for ANY return value != 0 */
106 if (unlikely(bio_rw_flagged(bio
, BIO_RW_BARRIER
) && !ok
)) {
107 /* Try again with no barrier */
108 dev_warn(DEV
, "Barriers not supported on meta data device - disabling\n");
109 set_bit(MD_NO_BARRIER
, &mdev
->flags
);
110 rw
&= ~(1 << BIO_RW_BARRIER
);
119 int drbd_md_sync_page_io(struct drbd_conf
*mdev
, struct drbd_backing_dev
*bdev
,
120 sector_t sector
, int rw
)
122 int logical_block_size
, mask
, ok
;
124 struct page
*iop
= mdev
->md_io_page
;
126 D_ASSERT(mutex_is_locked(&mdev
->md_io_mutex
));
128 BUG_ON(!bdev
->md_bdev
);
130 logical_block_size
= bdev_logical_block_size(bdev
->md_bdev
);
131 if (logical_block_size
== 0)
132 logical_block_size
= MD_SECTOR_SIZE
;
134 /* in case logical_block_size != 512 [ s390 only? ] */
135 if (logical_block_size
!= MD_SECTOR_SIZE
) {
136 mask
= (logical_block_size
/ MD_SECTOR_SIZE
) - 1;
137 D_ASSERT(mask
== 1 || mask
== 3 || mask
== 7);
138 D_ASSERT(logical_block_size
== (mask
+1) * MD_SECTOR_SIZE
);
139 offset
= sector
& mask
;
140 sector
= sector
& ~mask
;
141 iop
= mdev
->md_io_tmpp
;
144 /* these are GFP_KERNEL pages, pre-allocated
145 * on device initialization */
146 void *p
= page_address(mdev
->md_io_page
);
147 void *hp
= page_address(mdev
->md_io_tmpp
);
149 ok
= _drbd_md_sync_page_io(mdev
, bdev
, iop
, sector
,
150 READ
, logical_block_size
);
153 dev_err(DEV
, "drbd_md_sync_page_io(,%llus,"
154 "READ [logical_block_size!=512]) failed!\n",
155 (unsigned long long)sector
);
159 memcpy(hp
+ offset
*MD_SECTOR_SIZE
, p
, MD_SECTOR_SIZE
);
163 if (sector
< drbd_md_first_sector(bdev
) ||
164 sector
> drbd_md_last_sector(bdev
))
165 dev_alert(DEV
, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
166 current
->comm
, current
->pid
, __func__
,
167 (unsigned long long)sector
, (rw
& WRITE
) ? "WRITE" : "READ");
169 ok
= _drbd_md_sync_page_io(mdev
, bdev
, iop
, sector
, rw
, logical_block_size
);
171 dev_err(DEV
, "drbd_md_sync_page_io(,%llus,%s) failed!\n",
172 (unsigned long long)sector
, (rw
& WRITE
) ? "WRITE" : "READ");
176 if (logical_block_size
!= MD_SECTOR_SIZE
&& !(rw
& WRITE
)) {
177 void *p
= page_address(mdev
->md_io_page
);
178 void *hp
= page_address(mdev
->md_io_tmpp
);
180 memcpy(p
, hp
+ offset
*MD_SECTOR_SIZE
, MD_SECTOR_SIZE
);
186 static struct lc_element
*_al_get(struct drbd_conf
*mdev
, unsigned int enr
)
188 struct lc_element
*al_ext
;
189 struct lc_element
*tmp
;
190 unsigned long al_flags
= 0;
192 spin_lock_irq(&mdev
->al_lock
);
193 tmp
= lc_find(mdev
->resync
, enr
/AL_EXT_PER_BM_SECT
);
194 if (unlikely(tmp
!= NULL
)) {
195 struct bm_extent
*bm_ext
= lc_entry(tmp
, struct bm_extent
, lce
);
196 if (test_bit(BME_NO_WRITES
, &bm_ext
->flags
)) {
197 spin_unlock_irq(&mdev
->al_lock
);
201 al_ext
= lc_get(mdev
->act_log
, enr
);
202 al_flags
= mdev
->act_log
->flags
;
203 spin_unlock_irq(&mdev
->al_lock
);
207 if (al_flags & LC_STARVING)
208 dev_warn(DEV, "Have to wait for LRU element (AL too small?)\n");
209 if (al_flags & LC_DIRTY)
210 dev_warn(DEV, "Ongoing AL update (AL device too slow?)\n");
217 void drbd_al_begin_io(struct drbd_conf
*mdev
, sector_t sector
)
219 unsigned int enr
= (sector
>> (AL_EXTENT_SHIFT
-9));
220 struct lc_element
*al_ext
;
221 struct update_al_work al_work
;
223 D_ASSERT(atomic_read(&mdev
->local_cnt
) > 0);
225 wait_event(mdev
->al_wait
, (al_ext
= _al_get(mdev
, enr
)));
227 if (al_ext
->lc_number
!= enr
) {
228 /* drbd_al_write_transaction(mdev,al_ext,enr);
229 * recurses into generic_make_request(), which
230 * disallows recursion, bios being serialized on the
231 * current->bio_tail list now.
232 * we have to delegate updates to the activity log
233 * to the worker thread. */
234 init_completion(&al_work
.event
);
235 al_work
.al_ext
= al_ext
;
237 al_work
.old_enr
= al_ext
->lc_number
;
238 al_work
.w
.cb
= w_al_write_transaction
;
239 drbd_queue_work_front(&mdev
->data
.work
, &al_work
.w
);
240 wait_for_completion(&al_work
.event
);
244 spin_lock_irq(&mdev
->al_lock
);
245 lc_changed(mdev
->act_log
, al_ext
);
246 spin_unlock_irq(&mdev
->al_lock
);
247 wake_up(&mdev
->al_wait
);
251 void drbd_al_complete_io(struct drbd_conf
*mdev
, sector_t sector
)
253 unsigned int enr
= (sector
>> (AL_EXTENT_SHIFT
-9));
254 struct lc_element
*extent
;
257 spin_lock_irqsave(&mdev
->al_lock
, flags
);
259 extent
= lc_find(mdev
->act_log
, enr
);
262 spin_unlock_irqrestore(&mdev
->al_lock
, flags
);
263 dev_err(DEV
, "al_complete_io() called on inactive extent %u\n", enr
);
267 if (lc_put(mdev
->act_log
, extent
) == 0)
268 wake_up(&mdev
->al_wait
);
270 spin_unlock_irqrestore(&mdev
->al_lock
, flags
);
274 w_al_write_transaction(struct drbd_conf
*mdev
, struct drbd_work
*w
, int unused
)
276 struct update_al_work
*aw
= container_of(w
, struct update_al_work
, w
);
277 struct lc_element
*updated
= aw
->al_ext
;
278 const unsigned int new_enr
= aw
->enr
;
279 const unsigned int evicted
= aw
->old_enr
;
280 struct al_transaction
*buffer
;
283 unsigned int extent_nr
;
286 if (!get_ldev(mdev
)) {
287 dev_err(DEV
, "get_ldev() failed in w_al_write_transaction\n");
288 complete(&((struct update_al_work
*)w
)->event
);
291 /* do we have to do a bitmap write, first?
292 * TODO reduce maximum latency:
293 * submit both bios, then wait for both,
294 * instead of doing two synchronous sector writes. */
295 if (mdev
->state
.conn
< C_CONNECTED
&& evicted
!= LC_FREE
)
296 drbd_bm_write_sect(mdev
, evicted
/AL_EXT_PER_BM_SECT
);
298 mutex_lock(&mdev
->md_io_mutex
); /* protects md_io_page, al_tr_cycle, ... */
299 buffer
= (struct al_transaction
*)page_address(mdev
->md_io_page
);
301 buffer
->magic
= __constant_cpu_to_be32(DRBD_MAGIC
);
302 buffer
->tr_number
= cpu_to_be32(mdev
->al_tr_number
);
304 n
= lc_index_of(mdev
->act_log
, updated
);
306 buffer
->updates
[0].pos
= cpu_to_be32(n
);
307 buffer
->updates
[0].extent
= cpu_to_be32(new_enr
);
311 mx
= min_t(int, AL_EXTENTS_PT
,
312 mdev
->act_log
->nr_elements
- mdev
->al_tr_cycle
);
313 for (i
= 0; i
< mx
; i
++) {
314 unsigned idx
= mdev
->al_tr_cycle
+ i
;
315 extent_nr
= lc_element_by_index(mdev
->act_log
, idx
)->lc_number
;
316 buffer
->updates
[i
+1].pos
= cpu_to_be32(idx
);
317 buffer
->updates
[i
+1].extent
= cpu_to_be32(extent_nr
);
318 xor_sum
^= extent_nr
;
320 for (; i
< AL_EXTENTS_PT
; i
++) {
321 buffer
->updates
[i
+1].pos
= __constant_cpu_to_be32(-1);
322 buffer
->updates
[i
+1].extent
= __constant_cpu_to_be32(LC_FREE
);
325 mdev
->al_tr_cycle
+= AL_EXTENTS_PT
;
326 if (mdev
->al_tr_cycle
>= mdev
->act_log
->nr_elements
)
327 mdev
->al_tr_cycle
= 0;
329 buffer
->xor_sum
= cpu_to_be32(xor_sum
);
331 sector
= mdev
->ldev
->md
.md_offset
332 + mdev
->ldev
->md
.al_offset
+ mdev
->al_tr_pos
;
334 if (!drbd_md_sync_page_io(mdev
, mdev
->ldev
, sector
, WRITE
))
335 drbd_chk_io_error(mdev
, 1, TRUE
);
337 if (++mdev
->al_tr_pos
>
338 div_ceil(mdev
->act_log
->nr_elements
, AL_EXTENTS_PT
))
341 D_ASSERT(mdev
->al_tr_pos
< MD_AL_MAX_SIZE
);
342 mdev
->al_tr_number
++;
344 mutex_unlock(&mdev
->md_io_mutex
);
346 complete(&((struct update_al_work
*)w
)->event
);
353 * drbd_al_read_tr() - Read a single transaction from the on disk activity log
354 * @mdev: DRBD device.
355 * @bdev: Block device to read form.
356 * @b: pointer to an al_transaction.
357 * @index: On disk slot of the transaction to read.
359 * Returns -1 on IO error, 0 on checksum error and 1 upon success.
361 static int drbd_al_read_tr(struct drbd_conf
*mdev
,
362 struct drbd_backing_dev
*bdev
,
363 struct al_transaction
*b
,
370 sector
= bdev
->md
.md_offset
+ bdev
->md
.al_offset
+ index
;
372 /* Dont process error normally,
373 * as this is done before disk is attached! */
374 if (!drbd_md_sync_page_io(mdev
, bdev
, sector
, READ
))
377 rv
= (be32_to_cpu(b
->magic
) == DRBD_MAGIC
);
379 for (i
= 0; i
< AL_EXTENTS_PT
+ 1; i
++)
380 xor_sum
^= be32_to_cpu(b
->updates
[i
].extent
);
381 rv
&= (xor_sum
== be32_to_cpu(b
->xor_sum
));
387 * drbd_al_read_log() - Restores the activity log from its on disk representation.
388 * @mdev: DRBD device.
389 * @bdev: Block device to read form.
391 * Returns 1 on success, returns 0 when reading the log failed due to IO errors.
393 int drbd_al_read_log(struct drbd_conf
*mdev
, struct drbd_backing_dev
*bdev
)
395 struct al_transaction
*buffer
;
399 int active_extents
= 0;
400 int transactions
= 0;
408 mx
= div_ceil(mdev
->act_log
->nr_elements
, AL_EXTENTS_PT
);
410 /* lock out all other meta data io for now,
411 * and make sure the page is mapped.
413 mutex_lock(&mdev
->md_io_mutex
);
414 buffer
= page_address(mdev
->md_io_page
);
416 /* Find the valid transaction in the log */
417 for (i
= 0; i
<= mx
; i
++) {
418 rv
= drbd_al_read_tr(mdev
, bdev
, buffer
, i
);
422 mutex_unlock(&mdev
->md_io_mutex
);
425 cnr
= be32_to_cpu(buffer
->tr_number
);
427 if (++found_valid
== 1) {
434 if ((int)cnr
- (int)from_tnr
< 0) {
435 D_ASSERT(from_tnr
- cnr
+ i
- from
== mx
+1);
439 if ((int)cnr
- (int)to_tnr
> 0) {
440 D_ASSERT(cnr
- to_tnr
== i
- to
);
447 dev_warn(DEV
, "No usable activity log found.\n");
448 mutex_unlock(&mdev
->md_io_mutex
);
452 /* Read the valid transactions.
453 * dev_info(DEV, "Reading from %d to %d.\n",from,to); */
457 unsigned int extent_nr
;
460 rv
= drbd_al_read_tr(mdev
, bdev
, buffer
, i
);
461 ERR_IF(rv
== 0) goto cancel
;
463 mutex_unlock(&mdev
->md_io_mutex
);
467 trn
= be32_to_cpu(buffer
->tr_number
);
469 spin_lock_irq(&mdev
->al_lock
);
471 /* This loop runs backwards because in the cyclic
472 elements there might be an old version of the
473 updated element (in slot 0). So the element in slot 0
474 can overwrite old versions. */
475 for (j
= AL_EXTENTS_PT
; j
>= 0; j
--) {
476 pos
= be32_to_cpu(buffer
->updates
[j
].pos
);
477 extent_nr
= be32_to_cpu(buffer
->updates
[j
].extent
);
479 if (extent_nr
== LC_FREE
)
482 lc_set(mdev
->act_log
, extent_nr
, pos
);
485 spin_unlock_irq(&mdev
->al_lock
);
497 mdev
->al_tr_number
= to_tnr
+1;
498 mdev
->al_tr_pos
= to
;
499 if (++mdev
->al_tr_pos
>
500 div_ceil(mdev
->act_log
->nr_elements
, AL_EXTENTS_PT
))
503 /* ok, we are done with it */
504 mutex_unlock(&mdev
->md_io_mutex
);
506 dev_info(DEV
, "Found %d transactions (%d active extents) in activity log.\n",
507 transactions
, active_extents
);
512 static void atodb_endio(struct bio
*bio
, int error
)
514 struct drbd_atodb_wait
*wc
= bio
->bi_private
;
515 struct drbd_conf
*mdev
= wc
->mdev
;
517 int uptodate
= bio_flagged(bio
, BIO_UPTODATE
);
519 /* strange behavior of some lower level drivers...
520 * fail the request by clearing the uptodate flag,
521 * but do not return any error?! */
522 if (!error
&& !uptodate
)
525 drbd_chk_io_error(mdev
, error
, TRUE
);
526 if (error
&& wc
->error
== 0)
529 if (atomic_dec_and_test(&wc
->count
))
530 complete(&wc
->io_done
);
532 page
= bio
->bi_io_vec
[0].bv_page
;
539 #define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL))
540 /* activity log to on disk bitmap -- prepare bio unless that sector
541 * is already covered by previously prepared bios */
542 static int atodb_prepare_unless_covered(struct drbd_conf
*mdev
,
545 struct drbd_atodb_wait
*wc
) __must_hold(local
)
549 sector_t on_disk_sector
= enr
+ mdev
->ldev
->md
.md_offset
550 + mdev
->ldev
->md
.bm_offset
;
551 unsigned int page_offset
= PAGE_SIZE
;
556 /* Check if that enr is already covered by an already created bio.
557 * Caution, bios[] is not NULL terminated,
558 * but only initialized to all NULL.
559 * For completely scattered activity log,
560 * the last invocation iterates over all bios,
561 * and finds the last NULL entry.
563 while ((bio
= bios
[i
])) {
564 if (bio
->bi_sector
== on_disk_sector
)
568 /* bios[i] == NULL, the next not yet used slot */
570 /* GFP_KERNEL, we are not in the write-out path */
571 bio
= bio_alloc(GFP_KERNEL
, 1);
576 const struct bio_vec
*prev_bv
= bios
[i
-1]->bi_io_vec
;
577 page_offset
= prev_bv
->bv_offset
+ prev_bv
->bv_len
;
578 page
= prev_bv
->bv_page
;
580 if (page_offset
== PAGE_SIZE
) {
581 page
= alloc_page(__GFP_HIGHMEM
);
590 drbd_bm_get_lel(mdev
, offset
,
591 min_t(size_t, S2W(1), drbd_bm_words(mdev
) - offset
),
592 kmap(page
) + page_offset
);
595 bio
->bi_private
= wc
;
596 bio
->bi_end_io
= atodb_endio
;
597 bio
->bi_bdev
= mdev
->ldev
->md_bdev
;
598 bio
->bi_sector
= on_disk_sector
;
600 if (bio_add_page(bio
, page
, MD_SECTOR_SIZE
, page_offset
) != MD_SECTOR_SIZE
)
603 atomic_inc(&wc
->count
);
604 /* we already know that we may do this...
605 * get_ldev_if_state(mdev,D_ATTACHING);
606 * just get the extra reference, so that the local_cnt reflects
607 * the number of pending IO requests DRBD at its backing device.
609 atomic_inc(&mdev
->local_cnt
);
624 * drbd_al_to_on_disk_bm() - * Writes bitmap parts covered by active AL extents
625 * @mdev: DRBD device.
627 * Called when we detach (unconfigure) local storage,
628 * or when we go from R_PRIMARY to R_SECONDARY role.
630 void drbd_al_to_on_disk_bm(struct drbd_conf
*mdev
)
635 struct drbd_atodb_wait wc
;
637 ERR_IF (!get_ldev_if_state(mdev
, D_ATTACHING
))
638 return; /* sorry, I don't have any act_log etc... */
640 wait_event(mdev
->al_wait
, lc_try_lock(mdev
->act_log
));
642 nr_elements
= mdev
->act_log
->nr_elements
;
644 /* GFP_KERNEL, we are not in anyone's write-out path */
645 bios
= kzalloc(sizeof(struct bio
*) * nr_elements
, GFP_KERNEL
);
647 goto submit_one_by_one
;
649 atomic_set(&wc
.count
, 0);
650 init_completion(&wc
.io_done
);
654 for (i
= 0; i
< nr_elements
; i
++) {
655 enr
= lc_element_by_index(mdev
->act_log
, i
)->lc_number
;
658 /* next statement also does atomic_inc wc.count and local_cnt */
659 if (atodb_prepare_unless_covered(mdev
, bios
,
660 enr
/AL_EXT_PER_BM_SECT
,
662 goto free_bios_submit_one_by_one
;
665 /* unnecessary optimization? */
666 lc_unlock(mdev
->act_log
);
667 wake_up(&mdev
->al_wait
);
669 /* all prepared, submit them */
670 for (i
= 0; i
< nr_elements
; i
++) {
673 if (FAULT_ACTIVE(mdev
, DRBD_FAULT_MD_WR
)) {
674 bios
[i
]->bi_rw
= WRITE
;
675 bio_endio(bios
[i
], -EIO
);
677 submit_bio(WRITE
, bios
[i
]);
681 drbd_blk_run_queue(bdev_get_queue(mdev
->ldev
->md_bdev
));
683 /* always (try to) flush bitmap to stable storage */
686 /* In case we did not submit a single IO do not wait for
687 * them to complete. ( Because we would wait forever here. )
689 * In case we had IOs and they are already complete, there
690 * is not point in waiting anyways.
691 * Therefore this if () ... */
692 if (atomic_read(&wc
.count
))
693 wait_for_completion(&wc
.io_done
);
700 free_bios_submit_one_by_one
:
701 /* free everything by calling the endio callback directly. */
702 for (i
= 0; i
< nr_elements
&& bios
[i
]; i
++)
703 bio_endio(bios
[i
], 0);
708 dev_warn(DEV
, "Using the slow drbd_al_to_on_disk_bm()\n");
710 for (i
= 0; i
< mdev
->act_log
->nr_elements
; i
++) {
711 enr
= lc_element_by_index(mdev
->act_log
, i
)->lc_number
;
714 /* Really slow: if we have al-extents 16..19 active,
715 * sector 4 will be written four times! Synchronous! */
716 drbd_bm_write_sect(mdev
, enr
/AL_EXT_PER_BM_SECT
);
719 lc_unlock(mdev
->act_log
);
720 wake_up(&mdev
->al_wait
);
725 * drbd_al_apply_to_bm() - Sets the bitmap to diry(1) where covered ba active AL extents
726 * @mdev: DRBD device.
728 void drbd_al_apply_to_bm(struct drbd_conf
*mdev
)
731 unsigned long add
= 0;
735 wait_event(mdev
->al_wait
, lc_try_lock(mdev
->act_log
));
737 for (i
= 0; i
< mdev
->act_log
->nr_elements
; i
++) {
738 enr
= lc_element_by_index(mdev
->act_log
, i
)->lc_number
;
741 add
+= drbd_bm_ALe_set_all(mdev
, enr
);
744 lc_unlock(mdev
->act_log
);
745 wake_up(&mdev
->al_wait
);
747 dev_info(DEV
, "Marked additional %s as out-of-sync based on AL.\n",
748 ppsize(ppb
, Bit2KB(add
)));
751 static int _try_lc_del(struct drbd_conf
*mdev
, struct lc_element
*al_ext
)
755 spin_lock_irq(&mdev
->al_lock
);
756 rv
= (al_ext
->refcnt
== 0);
758 lc_del(mdev
->act_log
, al_ext
);
759 spin_unlock_irq(&mdev
->al_lock
);
765 * drbd_al_shrink() - Removes all active extents form the activity log
766 * @mdev: DRBD device.
768 * Removes all active extents form the activity log, waiting until
769 * the reference count of each entry dropped to 0 first, of course.
771 * You need to lock mdev->act_log with lc_try_lock() / lc_unlock()
773 void drbd_al_shrink(struct drbd_conf
*mdev
)
775 struct lc_element
*al_ext
;
778 D_ASSERT(test_bit(__LC_DIRTY
, &mdev
->act_log
->flags
));
780 for (i
= 0; i
< mdev
->act_log
->nr_elements
; i
++) {
781 al_ext
= lc_element_by_index(mdev
->act_log
, i
);
782 if (al_ext
->lc_number
== LC_FREE
)
784 wait_event(mdev
->al_wait
, _try_lc_del(mdev
, al_ext
));
787 wake_up(&mdev
->al_wait
);
790 static int w_update_odbm(struct drbd_conf
*mdev
, struct drbd_work
*w
, int unused
)
792 struct update_odbm_work
*udw
= container_of(w
, struct update_odbm_work
, w
);
794 if (!get_ldev(mdev
)) {
795 if (__ratelimit(&drbd_ratelimit_state
))
796 dev_warn(DEV
, "Can not update on disk bitmap, local IO disabled.\n");
801 drbd_bm_write_sect(mdev
, udw
->enr
);
806 if (drbd_bm_total_weight(mdev
) <= mdev
->rs_failed
) {
807 switch (mdev
->state
.conn
) {
808 case C_SYNC_SOURCE
: case C_SYNC_TARGET
:
809 case C_PAUSED_SYNC_S
: case C_PAUSED_SYNC_T
:
810 drbd_resync_finished(mdev
);
816 drbd_bcast_sync_progress(mdev
);
822 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
823 * resync LRU-cache are 16MB each.
824 * The caller of this function has to hold an get_ldev() reference.
826 * TODO will be obsoleted once we have a caching lru of the on disk bitmap
828 static void drbd_try_clear_on_disk_bm(struct drbd_conf
*mdev
, sector_t sector
,
829 int count
, int success
)
831 struct lc_element
*e
;
832 struct update_odbm_work
*udw
;
836 D_ASSERT(atomic_read(&mdev
->local_cnt
));
838 /* I simply assume that a sector/size pair never crosses
839 * a 16 MB extent border. (Currently this is true...) */
840 enr
= BM_SECT_TO_EXT(sector
);
842 e
= lc_get(mdev
->resync
, enr
);
844 struct bm_extent
*ext
= lc_entry(e
, struct bm_extent
, lce
);
845 if (ext
->lce
.lc_number
== enr
) {
847 ext
->rs_left
-= count
;
849 ext
->rs_failed
+= count
;
850 if (ext
->rs_left
< ext
->rs_failed
) {
851 dev_err(DEV
, "BAD! sector=%llus enr=%u rs_left=%d "
852 "rs_failed=%d count=%d\n",
853 (unsigned long long)sector
,
854 ext
->lce
.lc_number
, ext
->rs_left
,
855 ext
->rs_failed
, count
);
858 lc_put(mdev
->resync
, &ext
->lce
);
859 drbd_force_state(mdev
, NS(conn
, C_DISCONNECTING
));
863 /* Normally this element should be in the cache,
864 * since drbd_rs_begin_io() pulled it already in.
866 * But maybe an application write finished, and we set
867 * something outside the resync lru_cache in sync.
869 int rs_left
= drbd_bm_e_weight(mdev
, enr
);
870 if (ext
->flags
!= 0) {
871 dev_warn(DEV
, "changing resync lce: %d[%u;%02lx]"
873 ext
->lce
.lc_number
, ext
->rs_left
,
874 ext
->flags
, enr
, rs_left
);
877 if (ext
->rs_failed
) {
878 dev_warn(DEV
, "Kicking resync_lru element enr=%u "
879 "out with rs_failed=%d\n",
880 ext
->lce
.lc_number
, ext
->rs_failed
);
881 set_bit(WRITE_BM_AFTER_RESYNC
, &mdev
->flags
);
883 ext
->rs_left
= rs_left
;
884 ext
->rs_failed
= success
? 0 : count
;
885 lc_changed(mdev
->resync
, &ext
->lce
);
887 lc_put(mdev
->resync
, &ext
->lce
);
888 /* no race, we are within the al_lock! */
890 if (ext
->rs_left
== ext
->rs_failed
) {
893 udw
= kmalloc(sizeof(*udw
), GFP_ATOMIC
);
895 udw
->enr
= ext
->lce
.lc_number
;
896 udw
->w
.cb
= w_update_odbm
;
897 drbd_queue_work_front(&mdev
->data
.work
, &udw
->w
);
899 dev_warn(DEV
, "Could not kmalloc an udw\n");
900 set_bit(WRITE_BM_AFTER_RESYNC
, &mdev
->flags
);
904 dev_err(DEV
, "lc_get() failed! locked=%d/%d flags=%lu\n",
906 mdev
->resync
->nr_elements
,
907 mdev
->resync
->flags
);
911 /* clear the bit corresponding to the piece of storage in question:
912 * size byte of data starting from sector. Only clear a bits of the affected
913 * one ore more _aligned_ BM_BLOCK_SIZE blocks.
915 * called by worker on C_SYNC_TARGET and receiver on SyncSource.
918 void __drbd_set_in_sync(struct drbd_conf
*mdev
, sector_t sector
, int size
,
919 const char *file
, const unsigned int line
)
921 /* Is called from worker and receiver context _only_ */
922 unsigned long sbnr
, ebnr
, lbnr
;
923 unsigned long count
= 0;
924 sector_t esector
, nr_sectors
;
928 if (size
<= 0 || (size
& 0x1ff) != 0 || size
> DRBD_MAX_SEGMENT_SIZE
) {
929 dev_err(DEV
, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
930 (unsigned long long)sector
, size
);
933 nr_sectors
= drbd_get_capacity(mdev
->this_bdev
);
934 esector
= sector
+ (size
>> 9) - 1;
936 ERR_IF(sector
>= nr_sectors
) return;
937 ERR_IF(esector
>= nr_sectors
) esector
= (nr_sectors
-1);
939 lbnr
= BM_SECT_TO_BIT(nr_sectors
-1);
941 /* we clear it (in sync).
942 * round up start sector, round down end sector. we make sure we only
943 * clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
944 if (unlikely(esector
< BM_SECT_PER_BIT
-1))
946 if (unlikely(esector
== (nr_sectors
-1)))
949 ebnr
= BM_SECT_TO_BIT(esector
- (BM_SECT_PER_BIT
-1));
950 sbnr
= BM_SECT_TO_BIT(sector
+ BM_SECT_PER_BIT
-1);
956 * ok, (capacity & 7) != 0 sometimes, but who cares...
957 * we count rs_{total,left} in bits, not sectors.
959 spin_lock_irqsave(&mdev
->al_lock
, flags
);
960 count
= drbd_bm_clear_bits(mdev
, sbnr
, ebnr
);
962 /* we need the lock for drbd_try_clear_on_disk_bm */
963 if (jiffies
- mdev
->rs_mark_time
> HZ
*10) {
964 /* should be rolling marks,
965 * but we estimate only anyways. */
966 if (mdev
->rs_mark_left
!= drbd_bm_total_weight(mdev
) &&
967 mdev
->state
.conn
!= C_PAUSED_SYNC_T
&&
968 mdev
->state
.conn
!= C_PAUSED_SYNC_S
) {
969 mdev
->rs_mark_time
= jiffies
;
970 mdev
->rs_mark_left
= drbd_bm_total_weight(mdev
);
973 if (get_ldev(mdev
)) {
974 drbd_try_clear_on_disk_bm(mdev
, sector
, count
, TRUE
);
977 /* just wake_up unconditional now, various lc_chaged(),
978 * lc_put() in drbd_try_clear_on_disk_bm(). */
981 spin_unlock_irqrestore(&mdev
->al_lock
, flags
);
983 wake_up(&mdev
->al_wait
);
987 * this is intended to set one request worth of data out of sync.
988 * affects at least 1 bit,
989 * and at most 1+DRBD_MAX_SEGMENT_SIZE/BM_BLOCK_SIZE bits.
991 * called by tl_clear and drbd_send_dblock (==drbd_make_request).
992 * so this can be _any_ process.
994 void __drbd_set_out_of_sync(struct drbd_conf
*mdev
, sector_t sector
, int size
,
995 const char *file
, const unsigned int line
)
997 unsigned long sbnr
, ebnr
, lbnr
, flags
;
998 sector_t esector
, nr_sectors
;
999 unsigned int enr
, count
;
1000 struct lc_element
*e
;
1002 if (size
<= 0 || (size
& 0x1ff) != 0 || size
> DRBD_MAX_SEGMENT_SIZE
) {
1003 dev_err(DEV
, "sector: %llus, size: %d\n",
1004 (unsigned long long)sector
, size
);
1008 if (!get_ldev(mdev
))
1009 return; /* no disk, no metadata, no bitmap to set bits in */
1011 nr_sectors
= drbd_get_capacity(mdev
->this_bdev
);
1012 esector
= sector
+ (size
>> 9) - 1;
1014 ERR_IF(sector
>= nr_sectors
)
1016 ERR_IF(esector
>= nr_sectors
)
1017 esector
= (nr_sectors
-1);
1019 lbnr
= BM_SECT_TO_BIT(nr_sectors
-1);
1021 /* we set it out of sync,
1022 * we do not need to round anything here */
1023 sbnr
= BM_SECT_TO_BIT(sector
);
1024 ebnr
= BM_SECT_TO_BIT(esector
);
1026 /* ok, (capacity & 7) != 0 sometimes, but who cares...
1027 * we count rs_{total,left} in bits, not sectors. */
1028 spin_lock_irqsave(&mdev
->al_lock
, flags
);
1029 count
= drbd_bm_set_bits(mdev
, sbnr
, ebnr
);
1031 enr
= BM_SECT_TO_EXT(sector
);
1032 e
= lc_find(mdev
->resync
, enr
);
1034 lc_entry(e
, struct bm_extent
, lce
)->rs_left
+= count
;
1035 spin_unlock_irqrestore(&mdev
->al_lock
, flags
);
1042 struct bm_extent
*_bme_get(struct drbd_conf
*mdev
, unsigned int enr
)
1044 struct lc_element
*e
;
1045 struct bm_extent
*bm_ext
;
1047 unsigned long rs_flags
;
1049 spin_lock_irq(&mdev
->al_lock
);
1050 if (mdev
->resync_locked
> mdev
->resync
->nr_elements
/2) {
1051 spin_unlock_irq(&mdev
->al_lock
);
1054 e
= lc_get(mdev
->resync
, enr
);
1055 bm_ext
= e
? lc_entry(e
, struct bm_extent
, lce
) : NULL
;
1057 if (bm_ext
->lce
.lc_number
!= enr
) {
1058 bm_ext
->rs_left
= drbd_bm_e_weight(mdev
, enr
);
1059 bm_ext
->rs_failed
= 0;
1060 lc_changed(mdev
->resync
, &bm_ext
->lce
);
1063 if (bm_ext
->lce
.refcnt
== 1)
1064 mdev
->resync_locked
++;
1065 set_bit(BME_NO_WRITES
, &bm_ext
->flags
);
1067 rs_flags
= mdev
->resync
->flags
;
1068 spin_unlock_irq(&mdev
->al_lock
);
1070 wake_up(&mdev
->al_wait
);
1073 if (rs_flags
& LC_STARVING
)
1074 dev_warn(DEV
, "Have to wait for element"
1075 " (resync LRU too small?)\n");
1076 BUG_ON(rs_flags
& LC_DIRTY
);
1082 static int _is_in_al(struct drbd_conf
*mdev
, unsigned int enr
)
1084 struct lc_element
*al_ext
;
1087 spin_lock_irq(&mdev
->al_lock
);
1088 if (unlikely(enr
== mdev
->act_log
->new_number
))
1091 al_ext
= lc_find(mdev
->act_log
, enr
);
1097 spin_unlock_irq(&mdev
->al_lock
);
1101 dev_info(DEV, "Delaying sync read until app's write is done\n");
1108 * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
1109 * @mdev: DRBD device.
1110 * @sector: The sector number.
1112 * This functions sleeps on al_wait. Returns 1 on success, 0 if interrupted.
1114 int drbd_rs_begin_io(struct drbd_conf
*mdev
, sector_t sector
)
1116 unsigned int enr
= BM_SECT_TO_EXT(sector
);
1117 struct bm_extent
*bm_ext
;
1120 sig
= wait_event_interruptible(mdev
->al_wait
,
1121 (bm_ext
= _bme_get(mdev
, enr
)));
1125 if (test_bit(BME_LOCKED
, &bm_ext
->flags
))
1128 for (i
= 0; i
< AL_EXT_PER_BM_SECT
; i
++) {
1129 sig
= wait_event_interruptible(mdev
->al_wait
,
1130 !_is_in_al(mdev
, enr
* AL_EXT_PER_BM_SECT
+ i
));
1132 spin_lock_irq(&mdev
->al_lock
);
1133 if (lc_put(mdev
->resync
, &bm_ext
->lce
) == 0) {
1134 clear_bit(BME_NO_WRITES
, &bm_ext
->flags
);
1135 mdev
->resync_locked
--;
1136 wake_up(&mdev
->al_wait
);
1138 spin_unlock_irq(&mdev
->al_lock
);
1143 set_bit(BME_LOCKED
, &bm_ext
->flags
);
1149 * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1150 * @mdev: DRBD device.
1151 * @sector: The sector number.
1153 * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1154 * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1155 * if there is still application IO going on in this area.
1157 int drbd_try_rs_begin_io(struct drbd_conf
*mdev
, sector_t sector
)
1159 unsigned int enr
= BM_SECT_TO_EXT(sector
);
1160 const unsigned int al_enr
= enr
*AL_EXT_PER_BM_SECT
;
1161 struct lc_element
*e
;
1162 struct bm_extent
*bm_ext
;
1165 spin_lock_irq(&mdev
->al_lock
);
1166 if (mdev
->resync_wenr
!= LC_FREE
&& mdev
->resync_wenr
!= enr
) {
1167 /* in case you have very heavy scattered io, it may
1168 * stall the syncer undefined if we give up the ref count
1169 * when we try again and requeue.
1171 * if we don't give up the refcount, but the next time
1172 * we are scheduled this extent has been "synced" by new
1173 * application writes, we'd miss the lc_put on the
1174 * extent we keep the refcount on.
1175 * so we remembered which extent we had to try again, and
1176 * if the next requested one is something else, we do
1177 * the lc_put here...
1178 * we also have to wake_up
1180 e
= lc_find(mdev
->resync
, mdev
->resync_wenr
);
1181 bm_ext
= e
? lc_entry(e
, struct bm_extent
, lce
) : NULL
;
1183 D_ASSERT(!test_bit(BME_LOCKED
, &bm_ext
->flags
));
1184 D_ASSERT(test_bit(BME_NO_WRITES
, &bm_ext
->flags
));
1185 clear_bit(BME_NO_WRITES
, &bm_ext
->flags
);
1186 mdev
->resync_wenr
= LC_FREE
;
1187 if (lc_put(mdev
->resync
, &bm_ext
->lce
) == 0)
1188 mdev
->resync_locked
--;
1189 wake_up(&mdev
->al_wait
);
1191 dev_alert(DEV
, "LOGIC BUG\n");
1195 e
= lc_try_get(mdev
->resync
, enr
);
1196 bm_ext
= e
? lc_entry(e
, struct bm_extent
, lce
) : NULL
;
1198 if (test_bit(BME_LOCKED
, &bm_ext
->flags
))
1200 if (!test_and_set_bit(BME_NO_WRITES
, &bm_ext
->flags
)) {
1201 mdev
->resync_locked
++;
1203 /* we did set the BME_NO_WRITES,
1204 * but then could not set BME_LOCKED,
1205 * so we tried again.
1206 * drop the extra reference. */
1207 bm_ext
->lce
.refcnt
--;
1208 D_ASSERT(bm_ext
->lce
.refcnt
> 0);
1212 /* do we rather want to try later? */
1213 if (mdev
->resync_locked
> mdev
->resync
->nr_elements
-3)
1215 /* Do or do not. There is no try. -- Yoda */
1216 e
= lc_get(mdev
->resync
, enr
);
1217 bm_ext
= e
? lc_entry(e
, struct bm_extent
, lce
) : NULL
;
1219 const unsigned long rs_flags
= mdev
->resync
->flags
;
1220 if (rs_flags
& LC_STARVING
)
1221 dev_warn(DEV
, "Have to wait for element"
1222 " (resync LRU too small?)\n");
1223 BUG_ON(rs_flags
& LC_DIRTY
);
1226 if (bm_ext
->lce
.lc_number
!= enr
) {
1227 bm_ext
->rs_left
= drbd_bm_e_weight(mdev
, enr
);
1228 bm_ext
->rs_failed
= 0;
1229 lc_changed(mdev
->resync
, &bm_ext
->lce
);
1230 wake_up(&mdev
->al_wait
);
1231 D_ASSERT(test_bit(BME_LOCKED
, &bm_ext
->flags
) == 0);
1233 set_bit(BME_NO_WRITES
, &bm_ext
->flags
);
1234 D_ASSERT(bm_ext
->lce
.refcnt
== 1);
1235 mdev
->resync_locked
++;
1239 for (i
= 0; i
< AL_EXT_PER_BM_SECT
; i
++) {
1240 if (unlikely(al_enr
+i
== mdev
->act_log
->new_number
))
1242 if (lc_is_used(mdev
->act_log
, al_enr
+i
))
1245 set_bit(BME_LOCKED
, &bm_ext
->flags
);
1247 mdev
->resync_wenr
= LC_FREE
;
1248 spin_unlock_irq(&mdev
->al_lock
);
1253 mdev
->resync_wenr
= enr
;
1254 spin_unlock_irq(&mdev
->al_lock
);
1258 void drbd_rs_complete_io(struct drbd_conf
*mdev
, sector_t sector
)
1260 unsigned int enr
= BM_SECT_TO_EXT(sector
);
1261 struct lc_element
*e
;
1262 struct bm_extent
*bm_ext
;
1263 unsigned long flags
;
1265 spin_lock_irqsave(&mdev
->al_lock
, flags
);
1266 e
= lc_find(mdev
->resync
, enr
);
1267 bm_ext
= e
? lc_entry(e
, struct bm_extent
, lce
) : NULL
;
1269 spin_unlock_irqrestore(&mdev
->al_lock
, flags
);
1270 if (__ratelimit(&drbd_ratelimit_state
))
1271 dev_err(DEV
, "drbd_rs_complete_io() called, but extent not found\n");
1275 if (bm_ext
->lce
.refcnt
== 0) {
1276 spin_unlock_irqrestore(&mdev
->al_lock
, flags
);
1277 dev_err(DEV
, "drbd_rs_complete_io(,%llu [=%u]) called, "
1278 "but refcnt is 0!?\n",
1279 (unsigned long long)sector
, enr
);
1283 if (lc_put(mdev
->resync
, &bm_ext
->lce
) == 0) {
1284 clear_bit(BME_LOCKED
, &bm_ext
->flags
);
1285 clear_bit(BME_NO_WRITES
, &bm_ext
->flags
);
1286 mdev
->resync_locked
--;
1287 wake_up(&mdev
->al_wait
);
1290 spin_unlock_irqrestore(&mdev
->al_lock
, flags
);
1294 * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1295 * @mdev: DRBD device.
1297 void drbd_rs_cancel_all(struct drbd_conf
*mdev
)
1299 spin_lock_irq(&mdev
->al_lock
);
1301 if (get_ldev_if_state(mdev
, D_FAILED
)) { /* Makes sure ->resync is there. */
1302 lc_reset(mdev
->resync
);
1305 mdev
->resync_locked
= 0;
1306 mdev
->resync_wenr
= LC_FREE
;
1307 spin_unlock_irq(&mdev
->al_lock
);
1308 wake_up(&mdev
->al_wait
);
1312 * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1313 * @mdev: DRBD device.
1315 * Returns 0 upon success, -EAGAIN if at least one reference count was
1318 int drbd_rs_del_all(struct drbd_conf
*mdev
)
1320 struct lc_element
*e
;
1321 struct bm_extent
*bm_ext
;
1324 spin_lock_irq(&mdev
->al_lock
);
1326 if (get_ldev_if_state(mdev
, D_FAILED
)) {
1327 /* ok, ->resync is there. */
1328 for (i
= 0; i
< mdev
->resync
->nr_elements
; i
++) {
1329 e
= lc_element_by_index(mdev
->resync
, i
);
1330 bm_ext
= e
? lc_entry(e
, struct bm_extent
, lce
) : NULL
;
1331 if (bm_ext
->lce
.lc_number
== LC_FREE
)
1333 if (bm_ext
->lce
.lc_number
== mdev
->resync_wenr
) {
1334 dev_info(DEV
, "dropping %u in drbd_rs_del_all, apparently"
1335 " got 'synced' by application io\n",
1337 D_ASSERT(!test_bit(BME_LOCKED
, &bm_ext
->flags
));
1338 D_ASSERT(test_bit(BME_NO_WRITES
, &bm_ext
->flags
));
1339 clear_bit(BME_NO_WRITES
, &bm_ext
->flags
);
1340 mdev
->resync_wenr
= LC_FREE
;
1341 lc_put(mdev
->resync
, &bm_ext
->lce
);
1343 if (bm_ext
->lce
.refcnt
!= 0) {
1344 dev_info(DEV
, "Retrying drbd_rs_del_all() later. "
1345 "refcnt=%d\n", bm_ext
->lce
.refcnt
);
1347 spin_unlock_irq(&mdev
->al_lock
);
1350 D_ASSERT(!test_bit(BME_LOCKED
, &bm_ext
->flags
));
1351 D_ASSERT(!test_bit(BME_NO_WRITES
, &bm_ext
->flags
));
1352 lc_del(mdev
->resync
, &bm_ext
->lce
);
1354 D_ASSERT(mdev
->resync
->used
== 0);
1357 spin_unlock_irq(&mdev
->al_lock
);
1363 * drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
1364 * @mdev: DRBD device.
1365 * @sector: The sector number.
1366 * @size: Size of failed IO operation, in byte.
1368 void drbd_rs_failed_io(struct drbd_conf
*mdev
, sector_t sector
, int size
)
1370 /* Is called from worker and receiver context _only_ */
1371 unsigned long sbnr
, ebnr
, lbnr
;
1372 unsigned long count
;
1373 sector_t esector
, nr_sectors
;
1376 if (size
<= 0 || (size
& 0x1ff) != 0 || size
> DRBD_MAX_SEGMENT_SIZE
) {
1377 dev_err(DEV
, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
1378 (unsigned long long)sector
, size
);
1381 nr_sectors
= drbd_get_capacity(mdev
->this_bdev
);
1382 esector
= sector
+ (size
>> 9) - 1;
1384 ERR_IF(sector
>= nr_sectors
) return;
1385 ERR_IF(esector
>= nr_sectors
) esector
= (nr_sectors
-1);
1387 lbnr
= BM_SECT_TO_BIT(nr_sectors
-1);
1390 * round up start sector, round down end sector. we make sure we only
1391 * handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
1392 if (unlikely(esector
< BM_SECT_PER_BIT
-1))
1394 if (unlikely(esector
== (nr_sectors
-1)))
1397 ebnr
= BM_SECT_TO_BIT(esector
- (BM_SECT_PER_BIT
-1));
1398 sbnr
= BM_SECT_TO_BIT(sector
+ BM_SECT_PER_BIT
-1);
1404 * ok, (capacity & 7) != 0 sometimes, but who cares...
1405 * we count rs_{total,left} in bits, not sectors.
1407 spin_lock_irq(&mdev
->al_lock
);
1408 count
= drbd_bm_count_bits(mdev
, sbnr
, ebnr
);
1410 mdev
->rs_failed
+= count
;
1412 if (get_ldev(mdev
)) {
1413 drbd_try_clear_on_disk_bm(mdev
, sector
, count
, FALSE
);
1417 /* just wake_up unconditional now, various lc_chaged(),
1418 * lc_put() in drbd_try_clear_on_disk_bm(). */
1421 spin_unlock_irq(&mdev
->al_lock
);
1423 wake_up(&mdev
->al_wait
);