xref: /linux/fs/bcachefs/super.c (revision b74710eaff314d6afe4fb0bbe9bc7657bf226fd4)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * bcachefs setup/teardown code, and some metadata io - read a superblock and
4  * figure out what to do with it.
5  *
6  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
7  * Copyright 2012 Google, Inc.
8  */
9 
10 #include "bcachefs.h"
11 #include "alloc_background.h"
12 #include "alloc_foreground.h"
13 #include "async_objs.h"
14 #include "backpointers.h"
15 #include "bkey_sort.h"
16 #include "btree_cache.h"
17 #include "btree_gc.h"
18 #include "btree_journal_iter.h"
19 #include "btree_key_cache.h"
20 #include "btree_node_scan.h"
21 #include "btree_update_interior.h"
22 #include "btree_io.h"
23 #include "btree_write_buffer.h"
24 #include "buckets_waiting_for_journal.h"
25 #include "chardev.h"
26 #include "checksum.h"
27 #include "clock.h"
28 #include "compress.h"
29 #include "debug.h"
30 #include "disk_accounting.h"
31 #include "disk_groups.h"
32 #include "ec.h"
33 #include "enumerated_ref.h"
34 #include "errcode.h"
35 #include "error.h"
36 #include "fs.h"
37 #include "fs-io.h"
38 #include "fs-io-buffered.h"
39 #include "fs-io-direct.h"
40 #include "fsck.h"
41 #include "inode.h"
42 #include "io_read.h"
43 #include "io_write.h"
44 #include "journal.h"
45 #include "journal_reclaim.h"
46 #include "journal_seq_blacklist.h"
47 #include "move.h"
48 #include "migrate.h"
49 #include "movinggc.h"
50 #include "nocow_locking.h"
51 #include "quota.h"
52 #include "rebalance.h"
53 #include "recovery.h"
54 #include "recovery_passes.h"
55 #include "replicas.h"
56 #include "sb-clean.h"
57 #include "sb-counters.h"
58 #include "sb-errors.h"
59 #include "sb-members.h"
60 #include "snapshot.h"
61 #include "subvolume.h"
62 #include "super.h"
63 #include "super-io.h"
64 #include "sysfs.h"
65 #include "thread_with_file.h"
66 #include "trace.h"
67 
68 #include <linux/backing-dev.h>
69 #include <linux/blkdev.h>
70 #include <linux/debugfs.h>
71 #include <linux/device.h>
72 #include <linux/idr.h>
73 #include <linux/module.h>
74 #include <linux/percpu.h>
75 #include <linux/random.h>
76 #include <linux/sysfs.h>
77 
78 MODULE_LICENSE("GPL");
79 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
80 MODULE_DESCRIPTION("bcachefs filesystem");
81 
82 typedef DARRAY(struct bch_sb_handle) bch_sb_handles;
83 
84 #define x(n)		#n,
85 const char * const bch2_fs_flag_strs[] = {
86 	BCH_FS_FLAGS()
87 	NULL
88 };
89 
90 const char * const bch2_write_refs[] = {
91 	BCH_WRITE_REFS()
92 	NULL
93 };
94 
95 const char * const bch2_dev_read_refs[] = {
96 	BCH_DEV_READ_REFS()
97 	NULL
98 };
99 
100 const char * const bch2_dev_write_refs[] = {
101 	BCH_DEV_WRITE_REFS()
102 	NULL
103 };
104 #undef x
105 
106 static void __bch2_print_str(struct bch_fs *c, const char *prefix,
107 			     const char *str, bool nonblocking)
108 {
109 #ifdef __KERNEL__
110 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
111 
112 	if (unlikely(stdio)) {
113 		bch2_stdio_redirect_printf(stdio, true, "%s", str);
114 		return;
115 	}
116 #endif
117 	bch2_print_string_as_lines(KERN_ERR, str, nonblocking);
118 }
119 
120 void bch2_print_str(struct bch_fs *c, const char *prefix, const char *str)
121 {
122 	__bch2_print_str(c, prefix, str, false);
123 }
124 
125 void bch2_print_str_nonblocking(struct bch_fs *c, const char *prefix, const char *str)
126 {
127 	__bch2_print_str(c, prefix, str, true);
128 }
129 
130 __printf(2, 0)
131 static void bch2_print_maybe_redirect(struct stdio_redirect *stdio, const char *fmt, va_list args)
132 {
133 #ifdef __KERNEL__
134 	if (unlikely(stdio)) {
135 		if (fmt[0] == KERN_SOH[0])
136 			fmt += 2;
137 
138 		bch2_stdio_redirect_vprintf(stdio, true, fmt, args);
139 		return;
140 	}
141 #endif
142 	vprintk(fmt, args);
143 }
144 
145 void bch2_print_opts(struct bch_opts *opts, const char *fmt, ...)
146 {
147 	struct stdio_redirect *stdio = (void *)(unsigned long)opts->stdio;
148 
149 	va_list args;
150 	va_start(args, fmt);
151 	bch2_print_maybe_redirect(stdio, fmt, args);
152 	va_end(args);
153 }
154 
155 void __bch2_print(struct bch_fs *c, const char *fmt, ...)
156 {
157 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
158 
159 	va_list args;
160 	va_start(args, fmt);
161 	bch2_print_maybe_redirect(stdio, fmt, args);
162 	va_end(args);
163 }
164 
165 #define KTYPE(type)							\
166 static const struct attribute_group type ## _group = {			\
167 	.attrs = type ## _files						\
168 };									\
169 									\
170 static const struct attribute_group *type ## _groups[] = {		\
171 	&type ## _group,						\
172 	NULL								\
173 };									\
174 									\
175 static const struct kobj_type type ## _ktype = {			\
176 	.release	= type ## _release,				\
177 	.sysfs_ops	= &type ## _sysfs_ops,				\
178 	.default_groups = type ## _groups				\
179 }
180 
181 static void bch2_fs_release(struct kobject *);
182 static void bch2_dev_release(struct kobject *);
183 static void bch2_fs_counters_release(struct kobject *k)
184 {
185 }
186 
187 static void bch2_fs_internal_release(struct kobject *k)
188 {
189 }
190 
191 static void bch2_fs_opts_dir_release(struct kobject *k)
192 {
193 }
194 
195 static void bch2_fs_time_stats_release(struct kobject *k)
196 {
197 }
198 
199 KTYPE(bch2_fs);
200 KTYPE(bch2_fs_counters);
201 KTYPE(bch2_fs_internal);
202 KTYPE(bch2_fs_opts_dir);
203 KTYPE(bch2_fs_time_stats);
204 KTYPE(bch2_dev);
205 
206 static struct kset *bcachefs_kset;
207 static LIST_HEAD(bch_fs_list);
208 static DEFINE_MUTEX(bch_fs_list_lock);
209 
210 DECLARE_WAIT_QUEUE_HEAD(bch2_read_only_wait);
211 
212 static void bch2_dev_unlink(struct bch_dev *);
213 static void bch2_dev_free(struct bch_dev *);
214 static int bch2_dev_alloc(struct bch_fs *, unsigned);
215 static int bch2_dev_sysfs_online(struct bch_fs *, struct bch_dev *);
216 static void bch2_dev_io_ref_stop(struct bch_dev *, int);
217 static void __bch2_dev_read_only(struct bch_fs *, struct bch_dev *);
218 static int bch2_fs_init_rw(struct bch_fs *);
219 
220 struct bch_fs *bch2_dev_to_fs(dev_t dev)
221 {
222 	guard(mutex)(&bch_fs_list_lock);
223 	guard(rcu)();
224 
225 	struct bch_fs *c;
226 	list_for_each_entry(c, &bch_fs_list, list)
227 		for_each_member_device_rcu(c, ca, NULL)
228 			if (ca->disk_sb.bdev && ca->disk_sb.bdev->bd_dev == dev) {
229 				closure_get(&c->cl);
230 				return c;
231 			}
232 	return NULL;
233 }
234 
235 static struct bch_fs *__bch2_uuid_to_fs(__uuid_t uuid)
236 {
237 	struct bch_fs *c;
238 
239 	lockdep_assert_held(&bch_fs_list_lock);
240 
241 	list_for_each_entry(c, &bch_fs_list, list)
242 		if (!memcmp(&c->disk_sb.sb->uuid, &uuid, sizeof(uuid)))
243 			return c;
244 
245 	return NULL;
246 }
247 
248 struct bch_fs *bch2_uuid_to_fs(__uuid_t uuid)
249 {
250 	struct bch_fs *c;
251 
252 	mutex_lock(&bch_fs_list_lock);
253 	c = __bch2_uuid_to_fs(uuid);
254 	if (c)
255 		closure_get(&c->cl);
256 	mutex_unlock(&bch_fs_list_lock);
257 
258 	return c;
259 }
260 
261 /* Filesystem RO/RW: */
262 
263 /*
264  * For startup/shutdown of RW stuff, the dependencies are:
265  *
266  * - foreground writes depend on copygc and rebalance (to free up space)
267  *
268  * - copygc and rebalance depend on mark and sweep gc (they actually probably
269  *   don't because they either reserve ahead of time or don't block if
270  *   allocations fail, but allocations can require mark and sweep gc to run
271  *   because of generation number wraparound)
272  *
273  * - all of the above depends on the allocator threads
274  *
275  * - allocator depends on the journal (when it rewrites prios and gens)
276  */
277 
278 static void __bch2_fs_read_only(struct bch_fs *c)
279 {
280 	unsigned clean_passes = 0;
281 	u64 seq = 0;
282 
283 	bch2_fs_ec_stop(c);
284 	bch2_open_buckets_stop(c, NULL, true);
285 	bch2_rebalance_stop(c);
286 	bch2_copygc_stop(c);
287 	bch2_fs_ec_flush(c);
288 
289 	bch_verbose(c, "flushing journal and stopping allocators, journal seq %llu",
290 		    journal_cur_seq(&c->journal));
291 
292 	do {
293 		clean_passes++;
294 
295 		if (bch2_btree_interior_updates_flush(c) ||
296 		    bch2_btree_write_buffer_flush_going_ro(c) ||
297 		    bch2_journal_flush_all_pins(&c->journal) ||
298 		    bch2_btree_flush_all_writes(c) ||
299 		    seq != atomic64_read(&c->journal.seq)) {
300 			seq = atomic64_read(&c->journal.seq);
301 			clean_passes = 0;
302 		}
303 	} while (clean_passes < 2);
304 
305 	bch_verbose(c, "flushing journal and stopping allocators complete, journal seq %llu",
306 		    journal_cur_seq(&c->journal));
307 
308 	if (test_bit(JOURNAL_replay_done, &c->journal.flags) &&
309 	    !test_bit(BCH_FS_emergency_ro, &c->flags))
310 		set_bit(BCH_FS_clean_shutdown, &c->flags);
311 
312 	bch2_fs_journal_stop(&c->journal);
313 
314 	bch_info(c, "%sclean shutdown complete, journal seq %llu",
315 		 test_bit(BCH_FS_clean_shutdown, &c->flags) ? "" : "un",
316 		 c->journal.seq_ondisk);
317 
318 	/*
319 	 * After stopping journal:
320 	 */
321 	for_each_member_device(c, ca) {
322 		bch2_dev_io_ref_stop(ca, WRITE);
323 		bch2_dev_allocator_remove(c, ca);
324 	}
325 }
326 
327 static void bch2_writes_disabled(struct enumerated_ref *writes)
328 {
329 	struct bch_fs *c = container_of(writes, struct bch_fs, writes);
330 
331 	set_bit(BCH_FS_write_disable_complete, &c->flags);
332 	wake_up(&bch2_read_only_wait);
333 }
334 
335 void bch2_fs_read_only(struct bch_fs *c)
336 {
337 	if (!test_bit(BCH_FS_rw, &c->flags)) {
338 		bch2_journal_reclaim_stop(&c->journal);
339 		return;
340 	}
341 
342 	BUG_ON(test_bit(BCH_FS_write_disable_complete, &c->flags));
343 
344 	bch_verbose(c, "going read-only");
345 
346 	/*
347 	 * Block new foreground-end write operations from starting - any new
348 	 * writes will return -EROFS:
349 	 */
350 	set_bit(BCH_FS_going_ro, &c->flags);
351 	enumerated_ref_stop_async(&c->writes);
352 
353 	/*
354 	 * If we're not doing an emergency shutdown, we want to wait on
355 	 * outstanding writes to complete so they don't see spurious errors due
356 	 * to shutting down the allocator:
357 	 *
358 	 * If we are doing an emergency shutdown outstanding writes may
359 	 * hang until we shutdown the allocator so we don't want to wait
360 	 * on outstanding writes before shutting everything down - but
361 	 * we do need to wait on them before returning and signalling
362 	 * that going RO is complete:
363 	 */
364 	wait_event(bch2_read_only_wait,
365 		   test_bit(BCH_FS_write_disable_complete, &c->flags) ||
366 		   test_bit(BCH_FS_emergency_ro, &c->flags));
367 
368 	bool writes_disabled = test_bit(BCH_FS_write_disable_complete, &c->flags);
369 	if (writes_disabled)
370 		bch_verbose(c, "finished waiting for writes to stop");
371 
372 	__bch2_fs_read_only(c);
373 
374 	wait_event(bch2_read_only_wait,
375 		   test_bit(BCH_FS_write_disable_complete, &c->flags));
376 
377 	if (!writes_disabled)
378 		bch_verbose(c, "finished waiting for writes to stop");
379 
380 	clear_bit(BCH_FS_write_disable_complete, &c->flags);
381 	clear_bit(BCH_FS_going_ro, &c->flags);
382 	clear_bit(BCH_FS_rw, &c->flags);
383 
384 	if (!bch2_journal_error(&c->journal) &&
385 	    !test_bit(BCH_FS_error, &c->flags) &&
386 	    !test_bit(BCH_FS_emergency_ro, &c->flags) &&
387 	    test_bit(BCH_FS_started, &c->flags) &&
388 	    test_bit(BCH_FS_clean_shutdown, &c->flags) &&
389 	    c->recovery.pass_done >= BCH_RECOVERY_PASS_journal_replay) {
390 		BUG_ON(c->journal.last_empty_seq != journal_cur_seq(&c->journal));
391 		BUG_ON(atomic_long_read(&c->btree_cache.nr_dirty));
392 		BUG_ON(atomic_long_read(&c->btree_key_cache.nr_dirty));
393 		BUG_ON(c->btree_write_buffer.inc.keys.nr);
394 		BUG_ON(c->btree_write_buffer.flushing.keys.nr);
395 		bch2_verify_accounting_clean(c);
396 
397 		bch_verbose(c, "marking filesystem clean");
398 		bch2_fs_mark_clean(c);
399 	} else {
400 		/* Make sure error counts/counters are persisted */
401 		mutex_lock(&c->sb_lock);
402 		bch2_write_super(c);
403 		mutex_unlock(&c->sb_lock);
404 
405 		bch_verbose(c, "done going read-only, filesystem not clean");
406 	}
407 }
408 
409 static void bch2_fs_read_only_work(struct work_struct *work)
410 {
411 	struct bch_fs *c =
412 		container_of(work, struct bch_fs, read_only_work);
413 
414 	down_write(&c->state_lock);
415 	bch2_fs_read_only(c);
416 	up_write(&c->state_lock);
417 }
418 
419 static void bch2_fs_read_only_async(struct bch_fs *c)
420 {
421 	queue_work(system_long_wq, &c->read_only_work);
422 }
423 
424 bool bch2_fs_emergency_read_only(struct bch_fs *c)
425 {
426 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
427 
428 	bch2_journal_halt(&c->journal);
429 	bch2_fs_read_only_async(c);
430 
431 	wake_up(&bch2_read_only_wait);
432 	return ret;
433 }
434 
435 static bool __bch2_fs_emergency_read_only2(struct bch_fs *c, struct printbuf *out,
436 					   bool locked)
437 {
438 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
439 
440 	if (!locked)
441 		bch2_journal_halt(&c->journal);
442 	else
443 		bch2_journal_halt_locked(&c->journal);
444 	bch2_fs_read_only_async(c);
445 	wake_up(&bch2_read_only_wait);
446 
447 	if (ret)
448 		prt_printf(out, "emergency read only at seq %llu\n",
449 			   journal_cur_seq(&c->journal));
450 
451 	return ret;
452 }
453 
454 bool bch2_fs_emergency_read_only2(struct bch_fs *c, struct printbuf *out)
455 {
456 	return __bch2_fs_emergency_read_only2(c, out, false);
457 }
458 
459 bool bch2_fs_emergency_read_only_locked(struct bch_fs *c)
460 {
461 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
462 
463 	bch2_journal_halt_locked(&c->journal);
464 	bch2_fs_read_only_async(c);
465 
466 	wake_up(&bch2_read_only_wait);
467 	return ret;
468 }
469 
470 static int __bch2_fs_read_write(struct bch_fs *c, bool early)
471 {
472 	int ret;
473 
474 	BUG_ON(!test_bit(BCH_FS_may_go_rw, &c->flags));
475 
476 	if (WARN_ON(c->sb.features & BIT_ULL(BCH_FEATURE_no_alloc_info)))
477 		return bch_err_throw(c, erofs_no_alloc_info);
478 
479 	if (test_bit(BCH_FS_initial_gc_unfixed, &c->flags)) {
480 		bch_err(c, "cannot go rw, unfixed btree errors");
481 		return bch_err_throw(c, erofs_unfixed_errors);
482 	}
483 
484 	if (c->sb.features & BIT_ULL(BCH_FEATURE_small_image)) {
485 		bch_err(c, "cannot go rw, filesystem is an unresized image file");
486 		return bch_err_throw(c, erofs_filesystem_full);
487 	}
488 
489 	if (test_bit(BCH_FS_rw, &c->flags))
490 		return 0;
491 
492 	bch_info(c, "going read-write");
493 
494 	ret = bch2_fs_init_rw(c);
495 	if (ret)
496 		goto err;
497 
498 	ret = bch2_sb_members_v2_init(c);
499 	if (ret)
500 		goto err;
501 
502 	clear_bit(BCH_FS_clean_shutdown, &c->flags);
503 
504 	scoped_guard(rcu)
505 		for_each_online_member_rcu(c, ca)
506 			if (ca->mi.state == BCH_MEMBER_STATE_rw) {
507 				bch2_dev_allocator_add(c, ca);
508 				enumerated_ref_start(&ca->io_ref[WRITE]);
509 			}
510 
511 	bch2_recalc_capacity(c);
512 
513 	/*
514 	 * First journal write must be a flush write: after a clean shutdown we
515 	 * don't read the journal, so the first journal write may end up
516 	 * overwriting whatever was there previously, and there must always be
517 	 * at least one non-flush write in the journal or recovery will fail:
518 	 */
519 	spin_lock(&c->journal.lock);
520 	set_bit(JOURNAL_need_flush_write, &c->journal.flags);
521 	set_bit(JOURNAL_running, &c->journal.flags);
522 	bch2_journal_space_available(&c->journal);
523 	spin_unlock(&c->journal.lock);
524 
525 	ret = bch2_fs_mark_dirty(c);
526 	if (ret)
527 		goto err;
528 
529 	ret = bch2_journal_reclaim_start(&c->journal);
530 	if (ret)
531 		goto err;
532 
533 	set_bit(BCH_FS_rw, &c->flags);
534 	set_bit(BCH_FS_was_rw, &c->flags);
535 
536 	enumerated_ref_start(&c->writes);
537 
538 	ret = bch2_copygc_start(c);
539 	if (ret) {
540 		bch_err_msg(c, ret, "error starting copygc thread");
541 		goto err;
542 	}
543 
544 	ret = bch2_rebalance_start(c);
545 	if (ret) {
546 		bch_err_msg(c, ret, "error starting rebalance thread");
547 		goto err;
548 	}
549 
550 	bch2_do_discards(c);
551 	bch2_do_invalidates(c);
552 	bch2_do_stripe_deletes(c);
553 	bch2_do_pending_node_rewrites(c);
554 	return 0;
555 err:
556 	if (test_bit(BCH_FS_rw, &c->flags))
557 		bch2_fs_read_only(c);
558 	else
559 		__bch2_fs_read_only(c);
560 	return ret;
561 }
562 
563 int bch2_fs_read_write(struct bch_fs *c)
564 {
565 	if (c->opts.recovery_pass_last &&
566 	    c->opts.recovery_pass_last < BCH_RECOVERY_PASS_journal_replay)
567 		return bch_err_throw(c, erofs_norecovery);
568 
569 	if (c->opts.nochanges)
570 		return bch_err_throw(c, erofs_nochanges);
571 
572 	if (c->sb.features & BIT_ULL(BCH_FEATURE_no_alloc_info))
573 		return bch_err_throw(c, erofs_no_alloc_info);
574 
575 	return __bch2_fs_read_write(c, false);
576 }
577 
578 int bch2_fs_read_write_early(struct bch_fs *c)
579 {
580 	down_write(&c->state_lock);
581 	int ret = __bch2_fs_read_write(c, true);
582 	up_write(&c->state_lock);
583 
584 	return ret;
585 }
586 
587 /* Filesystem startup/shutdown: */
588 
589 static void __bch2_fs_free(struct bch_fs *c)
590 {
591 	for (unsigned i = 0; i < BCH_TIME_STAT_NR; i++)
592 		bch2_time_stats_exit(&c->times[i]);
593 
594 #ifdef CONFIG_UNICODE
595 	utf8_unload(c->cf_encoding);
596 #endif
597 
598 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
599 	bch2_free_pending_node_rewrites(c);
600 	bch2_free_fsck_errs(c);
601 	bch2_fs_vfs_exit(c);
602 	bch2_fs_snapshots_exit(c);
603 	bch2_fs_sb_errors_exit(c);
604 	bch2_fs_replicas_exit(c);
605 	bch2_fs_rebalance_exit(c);
606 	bch2_fs_quota_exit(c);
607 	bch2_fs_nocow_locking_exit(c);
608 	bch2_fs_journal_exit(&c->journal);
609 	bch2_fs_fs_io_direct_exit(c);
610 	bch2_fs_fs_io_buffered_exit(c);
611 	bch2_fs_fsio_exit(c);
612 	bch2_fs_io_write_exit(c);
613 	bch2_fs_io_read_exit(c);
614 	bch2_fs_encryption_exit(c);
615 	bch2_fs_ec_exit(c);
616 	bch2_fs_counters_exit(c);
617 	bch2_fs_compress_exit(c);
618 	bch2_io_clock_exit(&c->io_clock[WRITE]);
619 	bch2_io_clock_exit(&c->io_clock[READ]);
620 	bch2_fs_buckets_waiting_for_journal_exit(c);
621 	bch2_fs_btree_write_buffer_exit(c);
622 	bch2_fs_btree_key_cache_exit(&c->btree_key_cache);
623 	bch2_fs_btree_iter_exit(c);
624 	bch2_fs_btree_interior_update_exit(c);
625 	bch2_fs_btree_cache_exit(c);
626 	bch2_fs_accounting_exit(c);
627 	bch2_fs_async_obj_exit(c);
628 	bch2_journal_keys_put_initial(c);
629 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
630 
631 	BUG_ON(atomic_read(&c->journal_keys.ref));
632 	percpu_free_rwsem(&c->mark_lock);
633 	if (c->online_reserved) {
634 		u64 v = percpu_u64_get(c->online_reserved);
635 		WARN(v, "online_reserved not 0 at shutdown: %lli", v);
636 		free_percpu(c->online_reserved);
637 	}
638 
639 	darray_exit(&c->incompat_versions_requested);
640 	darray_exit(&c->btree_roots_extra);
641 	free_percpu(c->pcpu);
642 	free_percpu(c->usage);
643 	mempool_exit(&c->large_bkey_pool);
644 	mempool_exit(&c->btree_bounce_pool);
645 	bioset_exit(&c->btree_bio);
646 	mempool_exit(&c->fill_iter);
647 	enumerated_ref_exit(&c->writes);
648 	kfree(rcu_dereference_protected(c->disk_groups, 1));
649 	kfree(c->journal_seq_blacklist_table);
650 
651 	if (c->write_ref_wq)
652 		destroy_workqueue(c->write_ref_wq);
653 	if (c->btree_write_submit_wq)
654 		destroy_workqueue(c->btree_write_submit_wq);
655 	if (c->btree_read_complete_wq)
656 		destroy_workqueue(c->btree_read_complete_wq);
657 	if (c->copygc_wq)
658 		destroy_workqueue(c->copygc_wq);
659 	if (c->btree_write_complete_wq)
660 		destroy_workqueue(c->btree_write_complete_wq);
661 	if (c->btree_update_wq)
662 		destroy_workqueue(c->btree_update_wq);
663 
664 	bch2_free_super(&c->disk_sb);
665 	kvfree(c);
666 	module_put(THIS_MODULE);
667 }
668 
669 static void bch2_fs_release(struct kobject *kobj)
670 {
671 	struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
672 
673 	__bch2_fs_free(c);
674 }
675 
676 void __bch2_fs_stop(struct bch_fs *c)
677 {
678 	bch_verbose(c, "shutting down");
679 
680 	set_bit(BCH_FS_stopping, &c->flags);
681 
682 	down_write(&c->state_lock);
683 	bch2_fs_read_only(c);
684 	up_write(&c->state_lock);
685 
686 	for (unsigned i = 0; i < c->sb.nr_devices; i++) {
687 		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
688 		if (ca)
689 			bch2_dev_io_ref_stop(ca, READ);
690 	}
691 
692 	for_each_member_device(c, ca)
693 		bch2_dev_unlink(ca);
694 
695 	if (c->kobj.state_in_sysfs)
696 		kobject_del(&c->kobj);
697 
698 	bch2_fs_debug_exit(c);
699 	bch2_fs_chardev_exit(c);
700 
701 	bch2_ro_ref_put(c);
702 	wait_event(c->ro_ref_wait, !refcount_read(&c->ro_ref));
703 
704 	kobject_put(&c->counters_kobj);
705 	kobject_put(&c->time_stats);
706 	kobject_put(&c->opts_dir);
707 	kobject_put(&c->internal);
708 
709 	/* btree prefetch might have kicked off reads in the background: */
710 	bch2_btree_flush_all_reads(c);
711 
712 	for_each_member_device(c, ca)
713 		cancel_work_sync(&ca->io_error_work);
714 
715 	cancel_work_sync(&c->read_only_work);
716 }
717 
718 void bch2_fs_free(struct bch_fs *c)
719 {
720 	mutex_lock(&bch_fs_list_lock);
721 	list_del(&c->list);
722 	mutex_unlock(&bch_fs_list_lock);
723 
724 	closure_sync(&c->cl);
725 	closure_debug_destroy(&c->cl);
726 
727 	for (unsigned i = 0; i < c->sb.nr_devices; i++) {
728 		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
729 
730 		if (ca) {
731 			EBUG_ON(atomic_long_read(&ca->ref) != 1);
732 			bch2_dev_io_ref_stop(ca, READ);
733 			bch2_free_super(&ca->disk_sb);
734 			bch2_dev_free(ca);
735 		}
736 	}
737 
738 	bch_verbose(c, "shutdown complete");
739 
740 	kobject_put(&c->kobj);
741 }
742 
743 void bch2_fs_stop(struct bch_fs *c)
744 {
745 	__bch2_fs_stop(c);
746 	bch2_fs_free(c);
747 }
748 
749 static int bch2_fs_online(struct bch_fs *c)
750 {
751 	int ret = 0;
752 
753 	lockdep_assert_held(&bch_fs_list_lock);
754 
755 	if (c->sb.multi_device &&
756 	    __bch2_uuid_to_fs(c->sb.uuid)) {
757 		bch_err(c, "filesystem UUID already open");
758 		return bch_err_throw(c, filesystem_uuid_already_open);
759 	}
760 
761 	ret = bch2_fs_chardev_init(c);
762 	if (ret) {
763 		bch_err(c, "error creating character device");
764 		return ret;
765 	}
766 
767 	bch2_fs_debug_init(c);
768 
769 	ret = (c->sb.multi_device
770 	       ? kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b)
771 	       : kobject_add(&c->kobj, NULL, "%s", c->name)) ?:
772 	    kobject_add(&c->internal, &c->kobj, "internal") ?:
773 	    kobject_add(&c->opts_dir, &c->kobj, "options") ?:
774 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
775 	    kobject_add(&c->time_stats, &c->kobj, "time_stats") ?:
776 #endif
777 	    kobject_add(&c->counters_kobj, &c->kobj, "counters") ?:
778 	    bch2_opts_create_sysfs_files(&c->opts_dir, OPT_FS);
779 	if (ret) {
780 		bch_err(c, "error creating sysfs objects");
781 		return ret;
782 	}
783 
784 	down_write(&c->state_lock);
785 
786 	for_each_member_device(c, ca) {
787 		ret = bch2_dev_sysfs_online(c, ca);
788 		if (ret) {
789 			bch_err(c, "error creating sysfs objects");
790 			bch2_dev_put(ca);
791 			goto err;
792 		}
793 	}
794 
795 	BUG_ON(!list_empty(&c->list));
796 	list_add(&c->list, &bch_fs_list);
797 err:
798 	up_write(&c->state_lock);
799 	return ret;
800 }
801 
802 static int bch2_fs_init_rw(struct bch_fs *c)
803 {
804 	if (test_bit(BCH_FS_rw_init_done, &c->flags))
805 		return 0;
806 
807 	if (!(c->btree_update_wq = alloc_workqueue("bcachefs",
808 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_UNBOUND, 512)) ||
809 	    !(c->btree_write_complete_wq = alloc_workqueue("bcachefs_btree_write_complete",
810 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
811 	    !(c->copygc_wq = alloc_workqueue("bcachefs_copygc",
812 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 1)) ||
813 	    !(c->btree_write_submit_wq = alloc_workqueue("bcachefs_btree_write_sumit",
814 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
815 	    !(c->write_ref_wq = alloc_workqueue("bcachefs_write_ref",
816 				WQ_FREEZABLE, 0)))
817 		return bch_err_throw(c, ENOMEM_fs_other_alloc);
818 
819 	int ret = bch2_fs_btree_interior_update_init(c) ?:
820 		bch2_fs_btree_write_buffer_init(c) ?:
821 		bch2_fs_fs_io_buffered_init(c) ?:
822 		bch2_fs_io_write_init(c) ?:
823 		bch2_fs_journal_init(&c->journal);
824 	if (ret)
825 		return ret;
826 
827 	set_bit(BCH_FS_rw_init_done, &c->flags);
828 	return 0;
829 }
830 
831 static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts *opts,
832 				    bch_sb_handles *sbs)
833 {
834 	struct bch_fs *c;
835 	struct printbuf name = PRINTBUF;
836 	unsigned i, iter_size;
837 	int ret = 0;
838 
839 	c = kvmalloc(sizeof(struct bch_fs), GFP_KERNEL|__GFP_ZERO);
840 	if (!c) {
841 		c = ERR_PTR(-BCH_ERR_ENOMEM_fs_alloc);
842 		goto out;
843 	}
844 
845 	c->stdio = (void *)(unsigned long) opts->stdio;
846 
847 	__module_get(THIS_MODULE);
848 
849 	closure_init(&c->cl, NULL);
850 
851 	c->kobj.kset = bcachefs_kset;
852 	kobject_init(&c->kobj, &bch2_fs_ktype);
853 	kobject_init(&c->internal, &bch2_fs_internal_ktype);
854 	kobject_init(&c->opts_dir, &bch2_fs_opts_dir_ktype);
855 	kobject_init(&c->time_stats, &bch2_fs_time_stats_ktype);
856 	kobject_init(&c->counters_kobj, &bch2_fs_counters_ktype);
857 
858 	c->minor		= -1;
859 	c->disk_sb.fs_sb	= true;
860 
861 	init_rwsem(&c->state_lock);
862 	mutex_init(&c->sb_lock);
863 	mutex_init(&c->replicas_gc_lock);
864 	mutex_init(&c->btree_root_lock);
865 	INIT_WORK(&c->read_only_work, bch2_fs_read_only_work);
866 
867 	refcount_set(&c->ro_ref, 1);
868 	init_waitqueue_head(&c->ro_ref_wait);
869 
870 	for (i = 0; i < BCH_TIME_STAT_NR; i++)
871 		bch2_time_stats_init(&c->times[i]);
872 
873 	bch2_fs_allocator_background_init(c);
874 	bch2_fs_allocator_foreground_init(c);
875 	bch2_fs_btree_cache_init_early(&c->btree_cache);
876 	bch2_fs_btree_gc_init_early(c);
877 	bch2_fs_btree_interior_update_init_early(c);
878 	bch2_fs_btree_iter_init_early(c);
879 	bch2_fs_btree_key_cache_init_early(&c->btree_key_cache);
880 	bch2_fs_btree_write_buffer_init_early(c);
881 	bch2_fs_copygc_init(c);
882 	bch2_fs_ec_init_early(c);
883 	bch2_fs_journal_init_early(&c->journal);
884 	bch2_fs_journal_keys_init(c);
885 	bch2_fs_move_init(c);
886 	bch2_fs_nocow_locking_init_early(c);
887 	bch2_fs_quota_init(c);
888 	bch2_fs_recovery_passes_init(c);
889 	bch2_fs_sb_errors_init_early(c);
890 	bch2_fs_snapshots_init_early(c);
891 	bch2_fs_subvolumes_init_early(c);
892 
893 	INIT_LIST_HEAD(&c->list);
894 
895 	mutex_init(&c->bio_bounce_pages_lock);
896 	mutex_init(&c->snapshot_table_lock);
897 	init_rwsem(&c->snapshot_create_lock);
898 
899 	spin_lock_init(&c->btree_write_error_lock);
900 
901 	INIT_LIST_HEAD(&c->journal_iters);
902 
903 	INIT_LIST_HEAD(&c->fsck_error_msgs);
904 	mutex_init(&c->fsck_error_msgs_lock);
905 
906 	seqcount_init(&c->usage_lock);
907 
908 	sema_init(&c->io_in_flight, 128);
909 
910 	INIT_LIST_HEAD(&c->vfs_inodes_list);
911 	mutex_init(&c->vfs_inodes_lock);
912 
913 	c->journal.flush_write_time	= &c->times[BCH_TIME_journal_flush_write];
914 	c->journal.noflush_write_time	= &c->times[BCH_TIME_journal_noflush_write];
915 	c->journal.flush_seq_time	= &c->times[BCH_TIME_journal_flush_seq];
916 
917 	mutex_init(&c->sectors_available_lock);
918 
919 	ret = percpu_init_rwsem(&c->mark_lock);
920 	if (ret)
921 		goto err;
922 
923 	mutex_lock(&c->sb_lock);
924 	ret = bch2_sb_to_fs(c, sb);
925 	mutex_unlock(&c->sb_lock);
926 
927 	if (ret)
928 		goto err;
929 
930 	/* Compat: */
931 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
932 	    !BCH_SB_JOURNAL_FLUSH_DELAY(sb))
933 		SET_BCH_SB_JOURNAL_FLUSH_DELAY(sb, 1000);
934 
935 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
936 	    !BCH_SB_JOURNAL_RECLAIM_DELAY(sb))
937 		SET_BCH_SB_JOURNAL_RECLAIM_DELAY(sb, 100);
938 
939 	c->opts = bch2_opts_default;
940 	ret = bch2_opts_from_sb(&c->opts, sb);
941 	if (ret)
942 		goto err;
943 
944 	bch2_opts_apply(&c->opts, *opts);
945 
946 	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
947 	    c->opts.block_size > PAGE_SIZE) {
948 		bch_err(c, "cannot mount bs > ps filesystem without CONFIG_TRANSPARENT_HUGEPAGE");
949 		ret = -EINVAL;
950 		goto err;
951 	}
952 
953 	c->btree_key_cache_btrees |= 1U << BTREE_ID_alloc;
954 	if (c->opts.inodes_use_key_cache)
955 		c->btree_key_cache_btrees |= 1U << BTREE_ID_inodes;
956 	c->btree_key_cache_btrees |= 1U << BTREE_ID_logged_ops;
957 
958 	c->block_bits		= ilog2(block_sectors(c));
959 	c->btree_foreground_merge_threshold = BTREE_FOREGROUND_MERGE_THRESHOLD(c);
960 
961 	if (bch2_fs_init_fault("fs_alloc")) {
962 		bch_err(c, "fs_alloc fault injected");
963 		ret = -EFAULT;
964 		goto err;
965 	}
966 
967 	if (c->sb.multi_device)
968 		pr_uuid(&name, c->sb.user_uuid.b);
969 	else
970 		prt_bdevname(&name, sbs->data[0].bdev);
971 
972 	ret = name.allocation_failure ? -BCH_ERR_ENOMEM_fs_name_alloc : 0;
973 	if (ret)
974 		goto err;
975 
976 	strscpy(c->name, name.buf, sizeof(c->name));
977 	printbuf_exit(&name);
978 
979 	iter_size = sizeof(struct sort_iter) +
980 		(btree_blocks(c) + 1) * 2 *
981 		sizeof(struct sort_iter_set);
982 
983 	if (!(c->btree_read_complete_wq = alloc_workqueue("bcachefs_btree_read_complete",
984 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 512)) ||
985 	    enumerated_ref_init(&c->writes, BCH_WRITE_REF_NR,
986 				bch2_writes_disabled) ||
987 	    mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
988 	    bioset_init(&c->btree_bio, 1,
989 			max(offsetof(struct btree_read_bio, bio),
990 			    offsetof(struct btree_write_bio, wbio.bio)),
991 			BIOSET_NEED_BVECS) ||
992 	    !(c->pcpu = alloc_percpu(struct bch_fs_pcpu)) ||
993 	    !(c->usage = alloc_percpu(struct bch_fs_usage_base)) ||
994 	    !(c->online_reserved = alloc_percpu(u64)) ||
995 	    mempool_init_kvmalloc_pool(&c->btree_bounce_pool, 1,
996 				       c->opts.btree_node_size) ||
997 	    mempool_init_kmalloc_pool(&c->large_bkey_pool, 1, 2048)) {
998 		ret = bch_err_throw(c, ENOMEM_fs_other_alloc);
999 		goto err;
1000 	}
1001 
1002 	ret =
1003 	    bch2_fs_async_obj_init(c) ?:
1004 	    bch2_fs_btree_cache_init(c) ?:
1005 	    bch2_fs_btree_iter_init(c) ?:
1006 	    bch2_fs_btree_key_cache_init(&c->btree_key_cache) ?:
1007 	    bch2_fs_buckets_waiting_for_journal_init(c) ?:
1008 	    bch2_io_clock_init(&c->io_clock[READ]) ?:
1009 	    bch2_io_clock_init(&c->io_clock[WRITE]) ?:
1010 	    bch2_fs_compress_init(c) ?:
1011 	    bch2_fs_counters_init(c) ?:
1012 	    bch2_fs_ec_init(c) ?:
1013 	    bch2_fs_encryption_init(c) ?:
1014 	    bch2_fs_fsio_init(c) ?:
1015 	    bch2_fs_fs_io_direct_init(c) ?:
1016 	    bch2_fs_io_read_init(c) ?:
1017 	    bch2_fs_rebalance_init(c) ?:
1018 	    bch2_fs_sb_errors_init(c) ?:
1019 	    bch2_fs_vfs_init(c);
1020 	if (ret)
1021 		goto err;
1022 
1023 #ifdef CONFIG_UNICODE
1024 	/* Default encoding until we can potentially have more as an option. */
1025 	c->cf_encoding = utf8_load(BCH_FS_DEFAULT_UTF8_ENCODING);
1026 	if (IS_ERR(c->cf_encoding)) {
1027 		printk(KERN_ERR "Cannot load UTF-8 encoding for filesystem. Version: %u.%u.%u",
1028 			unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
1029 			unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
1030 			unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
1031 		ret = -EINVAL;
1032 		goto err;
1033 	}
1034 #else
1035 	if (c->sb.features & BIT_ULL(BCH_FEATURE_casefolding)) {
1036 		printk(KERN_ERR "Cannot mount a filesystem with casefolding on a kernel without CONFIG_UNICODE\n");
1037 		ret = -EINVAL;
1038 		goto err;
1039 	}
1040 #endif
1041 
1042 	for (i = 0; i < c->sb.nr_devices; i++) {
1043 		if (!bch2_member_exists(c->disk_sb.sb, i))
1044 			continue;
1045 		ret = bch2_dev_alloc(c, i);
1046 		if (ret)
1047 			goto err;
1048 	}
1049 
1050 	bch2_journal_entry_res_resize(&c->journal,
1051 			&c->btree_root_journal_res,
1052 			BTREE_ID_NR * (JSET_KEYS_U64s + BKEY_BTREE_PTR_U64s_MAX));
1053 	bch2_journal_entry_res_resize(&c->journal,
1054 			&c->clock_journal_res,
1055 			(sizeof(struct jset_entry_clock) / sizeof(u64)) * 2);
1056 
1057 	mutex_lock(&bch_fs_list_lock);
1058 	ret = bch2_fs_online(c);
1059 	mutex_unlock(&bch_fs_list_lock);
1060 
1061 	if (ret)
1062 		goto err;
1063 out:
1064 	return c;
1065 err:
1066 	bch2_fs_free(c);
1067 	c = ERR_PTR(ret);
1068 	goto out;
1069 }
1070 
1071 noinline_for_stack
1072 static void print_mount_opts(struct bch_fs *c)
1073 {
1074 	enum bch_opt_id i;
1075 	struct printbuf p = PRINTBUF;
1076 	bool first = true;
1077 
1078 	prt_str(&p, "starting version ");
1079 	bch2_version_to_text(&p, c->sb.version);
1080 
1081 	for (i = 0; i < bch2_opts_nr; i++) {
1082 		const struct bch_option *opt = &bch2_opt_table[i];
1083 		u64 v = bch2_opt_get_by_id(&c->opts, i);
1084 
1085 		if (!(opt->flags & OPT_MOUNT))
1086 			continue;
1087 
1088 		if (v == bch2_opt_get_by_id(&bch2_opts_default, i))
1089 			continue;
1090 
1091 		prt_str(&p, first ? " opts=" : ",");
1092 		first = false;
1093 		bch2_opt_to_text(&p, c, c->disk_sb.sb, opt, v, OPT_SHOW_MOUNT_STYLE);
1094 	}
1095 
1096 	if (c->sb.version_incompat_allowed != c->sb.version) {
1097 		prt_printf(&p, "\n  allowing incompatible features above ");
1098 		bch2_version_to_text(&p, c->sb.version_incompat_allowed);
1099 	}
1100 
1101 	if (c->opts.verbose) {
1102 		prt_printf(&p, "\n  features: ");
1103 		prt_bitflags(&p, bch2_sb_features, c->sb.features);
1104 	}
1105 
1106 	bch_info(c, "%s", p.buf);
1107 	printbuf_exit(&p);
1108 }
1109 
1110 static bool bch2_fs_may_start(struct bch_fs *c)
1111 {
1112 	struct bch_dev *ca;
1113 	unsigned flags = 0;
1114 
1115 	switch (c->opts.degraded) {
1116 	case BCH_DEGRADED_very:
1117 		flags |= BCH_FORCE_IF_DEGRADED|BCH_FORCE_IF_LOST;
1118 		break;
1119 	case BCH_DEGRADED_yes:
1120 		flags |= BCH_FORCE_IF_DEGRADED;
1121 		break;
1122 	default:
1123 		mutex_lock(&c->sb_lock);
1124 		for (unsigned i = 0; i < c->disk_sb.sb->nr_devices; i++) {
1125 			if (!bch2_member_exists(c->disk_sb.sb, i))
1126 				continue;
1127 
1128 			ca = bch2_dev_locked(c, i);
1129 
1130 			if (!bch2_dev_is_online(ca) &&
1131 			    (ca->mi.state == BCH_MEMBER_STATE_rw ||
1132 			     ca->mi.state == BCH_MEMBER_STATE_ro)) {
1133 				mutex_unlock(&c->sb_lock);
1134 				return false;
1135 			}
1136 		}
1137 		mutex_unlock(&c->sb_lock);
1138 		break;
1139 	}
1140 
1141 	return bch2_have_enough_devs(c, c->online_devs, flags, true);
1142 }
1143 
1144 int bch2_fs_start(struct bch_fs *c)
1145 {
1146 	time64_t now = ktime_get_real_seconds();
1147 	int ret = 0;
1148 
1149 	print_mount_opts(c);
1150 
1151 #ifdef CONFIG_UNICODE
1152 	bch_info(c, "Using encoding defined by superblock: utf8-%u.%u.%u",
1153 		 unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
1154 		 unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
1155 		 unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
1156 #endif
1157 
1158 	if (!bch2_fs_may_start(c))
1159 		return bch_err_throw(c, insufficient_devices_to_start);
1160 
1161 	down_write(&c->state_lock);
1162 	mutex_lock(&c->sb_lock);
1163 
1164 	BUG_ON(test_bit(BCH_FS_started, &c->flags));
1165 
1166 	if (!bch2_sb_field_get_minsize(&c->disk_sb, ext,
1167 			sizeof(struct bch_sb_field_ext) / sizeof(u64))) {
1168 		mutex_unlock(&c->sb_lock);
1169 		up_write(&c->state_lock);
1170 		ret = bch_err_throw(c, ENOSPC_sb);
1171 		goto err;
1172 	}
1173 
1174 	ret = bch2_sb_members_v2_init(c);
1175 	if (ret) {
1176 		mutex_unlock(&c->sb_lock);
1177 		up_write(&c->state_lock);
1178 		goto err;
1179 	}
1180 
1181 	scoped_guard(rcu)
1182 		for_each_online_member_rcu(c, ca)
1183 			bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount =
1184 			cpu_to_le64(now);
1185 
1186 	/*
1187 	 * Dno't write superblock yet: recovery might have to downgrade
1188 	 */
1189 	mutex_unlock(&c->sb_lock);
1190 
1191 	scoped_guard(rcu)
1192 		for_each_online_member_rcu(c, ca)
1193 			if (ca->mi.state == BCH_MEMBER_STATE_rw)
1194 				bch2_dev_allocator_add(c, ca);
1195 	bch2_recalc_capacity(c);
1196 	up_write(&c->state_lock);
1197 
1198 	c->recovery_task = current;
1199 	ret = BCH_SB_INITIALIZED(c->disk_sb.sb)
1200 		? bch2_fs_recovery(c)
1201 		: bch2_fs_initialize(c);
1202 	c->recovery_task = NULL;
1203 
1204 	if (ret)
1205 		goto err;
1206 
1207 	ret = bch2_opts_hooks_pre_set(c);
1208 	if (ret)
1209 		goto err;
1210 
1211 	if (bch2_fs_init_fault("fs_start")) {
1212 		ret = bch_err_throw(c, injected_fs_start);
1213 		goto err;
1214 	}
1215 
1216 	set_bit(BCH_FS_started, &c->flags);
1217 	wake_up(&c->ro_ref_wait);
1218 
1219 	down_write(&c->state_lock);
1220 	if (c->opts.read_only)
1221 		bch2_fs_read_only(c);
1222 	else if (!test_bit(BCH_FS_rw, &c->flags))
1223 		ret = bch2_fs_read_write(c);
1224 	up_write(&c->state_lock);
1225 
1226 err:
1227 	if (ret)
1228 		bch_err_msg(c, ret, "starting filesystem");
1229 	else
1230 		bch_verbose(c, "done starting filesystem");
1231 	return ret;
1232 }
1233 
1234 static int bch2_dev_may_add(struct bch_sb *sb, struct bch_fs *c)
1235 {
1236 	struct bch_member m = bch2_sb_member_get(sb, sb->dev_idx);
1237 
1238 	if (le16_to_cpu(sb->block_size) != block_sectors(c))
1239 		return bch_err_throw(c, mismatched_block_size);
1240 
1241 	if (le16_to_cpu(m.bucket_size) <
1242 	    BCH_SB_BTREE_NODE_SIZE(c->disk_sb.sb))
1243 		return bch_err_throw(c, bucket_size_too_small);
1244 
1245 	return 0;
1246 }
1247 
1248 static int bch2_dev_in_fs(struct bch_sb_handle *fs,
1249 			  struct bch_sb_handle *sb,
1250 			  struct bch_opts *opts)
1251 {
1252 	if (fs == sb)
1253 		return 0;
1254 
1255 	if (!uuid_equal(&fs->sb->uuid, &sb->sb->uuid))
1256 		return -BCH_ERR_device_not_a_member_of_filesystem;
1257 
1258 	if (!bch2_member_exists(fs->sb, sb->sb->dev_idx))
1259 		return -BCH_ERR_device_has_been_removed;
1260 
1261 	if (fs->sb->block_size != sb->sb->block_size)
1262 		return -BCH_ERR_mismatched_block_size;
1263 
1264 	if (le16_to_cpu(fs->sb->version) < bcachefs_metadata_version_member_seq ||
1265 	    le16_to_cpu(sb->sb->version) < bcachefs_metadata_version_member_seq)
1266 		return 0;
1267 
1268 	if (fs->sb->seq == sb->sb->seq &&
1269 	    fs->sb->write_time != sb->sb->write_time) {
1270 		struct printbuf buf = PRINTBUF;
1271 
1272 		prt_str(&buf, "Split brain detected between ");
1273 		prt_bdevname(&buf, sb->bdev);
1274 		prt_str(&buf, " and ");
1275 		prt_bdevname(&buf, fs->bdev);
1276 		prt_char(&buf, ':');
1277 		prt_newline(&buf);
1278 		prt_printf(&buf, "seq=%llu but write_time different, got", le64_to_cpu(sb->sb->seq));
1279 		prt_newline(&buf);
1280 
1281 		prt_bdevname(&buf, fs->bdev);
1282 		prt_char(&buf, ' ');
1283 		bch2_prt_datetime(&buf, le64_to_cpu(fs->sb->write_time));
1284 		prt_newline(&buf);
1285 
1286 		prt_bdevname(&buf, sb->bdev);
1287 		prt_char(&buf, ' ');
1288 		bch2_prt_datetime(&buf, le64_to_cpu(sb->sb->write_time));
1289 		prt_newline(&buf);
1290 
1291 		if (!opts->no_splitbrain_check)
1292 			prt_printf(&buf, "Not using older sb");
1293 
1294 		pr_err("%s", buf.buf);
1295 		printbuf_exit(&buf);
1296 
1297 		if (!opts->no_splitbrain_check)
1298 			return -BCH_ERR_device_splitbrain;
1299 	}
1300 
1301 	struct bch_member m = bch2_sb_member_get(fs->sb, sb->sb->dev_idx);
1302 	u64 seq_from_fs		= le64_to_cpu(m.seq);
1303 	u64 seq_from_member	= le64_to_cpu(sb->sb->seq);
1304 
1305 	if (seq_from_fs && seq_from_fs < seq_from_member) {
1306 		struct printbuf buf = PRINTBUF;
1307 
1308 		prt_str(&buf, "Split brain detected between ");
1309 		prt_bdevname(&buf, sb->bdev);
1310 		prt_str(&buf, " and ");
1311 		prt_bdevname(&buf, fs->bdev);
1312 		prt_char(&buf, ':');
1313 		prt_newline(&buf);
1314 
1315 		prt_bdevname(&buf, fs->bdev);
1316 		prt_str(&buf, " believes seq of ");
1317 		prt_bdevname(&buf, sb->bdev);
1318 		prt_printf(&buf, " to be %llu, but ", seq_from_fs);
1319 		prt_bdevname(&buf, sb->bdev);
1320 		prt_printf(&buf, " has %llu\n", seq_from_member);
1321 
1322 		if (!opts->no_splitbrain_check) {
1323 			prt_str(&buf, "Not using ");
1324 			prt_bdevname(&buf, sb->bdev);
1325 		}
1326 
1327 		pr_err("%s", buf.buf);
1328 		printbuf_exit(&buf);
1329 
1330 		if (!opts->no_splitbrain_check)
1331 			return -BCH_ERR_device_splitbrain;
1332 	}
1333 
1334 	return 0;
1335 }
1336 
1337 /* Device startup/shutdown: */
1338 
1339 static void bch2_dev_io_ref_stop(struct bch_dev *ca, int rw)
1340 {
1341 	if (rw == READ)
1342 		clear_bit(ca->dev_idx, ca->fs->online_devs.d);
1343 
1344 	if (!enumerated_ref_is_zero(&ca->io_ref[rw]))
1345 		enumerated_ref_stop(&ca->io_ref[rw],
1346 				    rw == READ
1347 				    ? bch2_dev_read_refs
1348 				    : bch2_dev_write_refs);
1349 }
1350 
1351 static void bch2_dev_release(struct kobject *kobj)
1352 {
1353 	struct bch_dev *ca = container_of(kobj, struct bch_dev, kobj);
1354 
1355 	kfree(ca);
1356 }
1357 
1358 static void bch2_dev_free(struct bch_dev *ca)
1359 {
1360 	WARN_ON(!enumerated_ref_is_zero(&ca->io_ref[WRITE]));
1361 	WARN_ON(!enumerated_ref_is_zero(&ca->io_ref[READ]));
1362 
1363 	cancel_work_sync(&ca->io_error_work);
1364 
1365 	bch2_dev_unlink(ca);
1366 
1367 	if (ca->kobj.state_in_sysfs)
1368 		kobject_del(&ca->kobj);
1369 
1370 	bch2_bucket_bitmap_free(&ca->bucket_backpointer_mismatch);
1371 	bch2_bucket_bitmap_free(&ca->bucket_backpointer_empty);
1372 
1373 	bch2_free_super(&ca->disk_sb);
1374 	bch2_dev_allocator_background_exit(ca);
1375 	bch2_dev_journal_exit(ca);
1376 
1377 	free_percpu(ca->io_done);
1378 	bch2_dev_buckets_free(ca);
1379 	kfree(ca->sb_read_scratch);
1380 
1381 	bch2_time_stats_quantiles_exit(&ca->io_latency[WRITE]);
1382 	bch2_time_stats_quantiles_exit(&ca->io_latency[READ]);
1383 
1384 	enumerated_ref_exit(&ca->io_ref[WRITE]);
1385 	enumerated_ref_exit(&ca->io_ref[READ]);
1386 #ifndef CONFIG_BCACHEFS_DEBUG
1387 	percpu_ref_exit(&ca->ref);
1388 #endif
1389 	kobject_put(&ca->kobj);
1390 }
1391 
1392 static void __bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca)
1393 {
1394 
1395 	lockdep_assert_held(&c->state_lock);
1396 
1397 	if (enumerated_ref_is_zero(&ca->io_ref[READ]))
1398 		return;
1399 
1400 	__bch2_dev_read_only(c, ca);
1401 
1402 	bch2_dev_io_ref_stop(ca, READ);
1403 
1404 	bch2_dev_unlink(ca);
1405 
1406 	bch2_free_super(&ca->disk_sb);
1407 	bch2_dev_journal_exit(ca);
1408 }
1409 
1410 #ifndef CONFIG_BCACHEFS_DEBUG
1411 static void bch2_dev_ref_complete(struct percpu_ref *ref)
1412 {
1413 	struct bch_dev *ca = container_of(ref, struct bch_dev, ref);
1414 
1415 	complete(&ca->ref_completion);
1416 }
1417 #endif
1418 
1419 static void bch2_dev_unlink(struct bch_dev *ca)
1420 {
1421 	struct kobject *b;
1422 
1423 	/*
1424 	 * This is racy w.r.t. the underlying block device being hot-removed,
1425 	 * which removes it from sysfs.
1426 	 *
1427 	 * It'd be lovely if we had a way to handle this race, but the sysfs
1428 	 * code doesn't appear to provide a good method and block/holder.c is
1429 	 * susceptible as well:
1430 	 */
1431 	if (ca->kobj.state_in_sysfs &&
1432 	    ca->disk_sb.bdev &&
1433 	    (b = bdev_kobj(ca->disk_sb.bdev))->state_in_sysfs) {
1434 		sysfs_remove_link(b, "bcachefs");
1435 		sysfs_remove_link(&ca->kobj, "block");
1436 	}
1437 }
1438 
1439 static int bch2_dev_sysfs_online(struct bch_fs *c, struct bch_dev *ca)
1440 {
1441 	int ret;
1442 
1443 	if (!c->kobj.state_in_sysfs)
1444 		return 0;
1445 
1446 	if (!ca->kobj.state_in_sysfs) {
1447 		ret =   kobject_add(&ca->kobj, &c->kobj, "dev-%u", ca->dev_idx) ?:
1448 			bch2_opts_create_sysfs_files(&ca->kobj, OPT_DEVICE);
1449 		if (ret)
1450 			return ret;
1451 	}
1452 
1453 	if (ca->disk_sb.bdev) {
1454 		struct kobject *block = bdev_kobj(ca->disk_sb.bdev);
1455 
1456 		ret = sysfs_create_link(block, &ca->kobj, "bcachefs");
1457 		if (ret)
1458 			return ret;
1459 
1460 		ret = sysfs_create_link(&ca->kobj, block, "block");
1461 		if (ret)
1462 			return ret;
1463 	}
1464 
1465 	return 0;
1466 }
1467 
1468 static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
1469 					struct bch_member *member)
1470 {
1471 	struct bch_dev *ca;
1472 	unsigned i;
1473 
1474 	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
1475 	if (!ca)
1476 		return NULL;
1477 
1478 	kobject_init(&ca->kobj, &bch2_dev_ktype);
1479 	init_completion(&ca->ref_completion);
1480 
1481 	INIT_WORK(&ca->io_error_work, bch2_io_error_work);
1482 
1483 	bch2_time_stats_quantiles_init(&ca->io_latency[READ]);
1484 	bch2_time_stats_quantiles_init(&ca->io_latency[WRITE]);
1485 
1486 	ca->mi = bch2_mi_to_cpu(member);
1487 
1488 	for (i = 0; i < ARRAY_SIZE(member->errors); i++)
1489 		atomic64_set(&ca->errors[i], le64_to_cpu(member->errors[i]));
1490 
1491 	ca->uuid = member->uuid;
1492 
1493 	ca->nr_btree_reserve = DIV_ROUND_UP(BTREE_NODE_RESERVE,
1494 			     ca->mi.bucket_size / btree_sectors(c));
1495 
1496 #ifndef CONFIG_BCACHEFS_DEBUG
1497 	if (percpu_ref_init(&ca->ref, bch2_dev_ref_complete, 0, GFP_KERNEL))
1498 		goto err;
1499 #else
1500 	atomic_long_set(&ca->ref, 1);
1501 #endif
1502 
1503 	mutex_init(&ca->bucket_backpointer_mismatch.lock);
1504 	mutex_init(&ca->bucket_backpointer_empty.lock);
1505 
1506 	bch2_dev_allocator_background_init(ca);
1507 
1508 	if (enumerated_ref_init(&ca->io_ref[READ],  BCH_DEV_READ_REF_NR,  NULL) ||
1509 	    enumerated_ref_init(&ca->io_ref[WRITE], BCH_DEV_WRITE_REF_NR, NULL) ||
1510 	    !(ca->sb_read_scratch = kmalloc(BCH_SB_READ_SCRATCH_BUF_SIZE, GFP_KERNEL)) ||
1511 	    bch2_dev_buckets_alloc(c, ca) ||
1512 	    !(ca->io_done	= alloc_percpu(*ca->io_done)))
1513 		goto err;
1514 
1515 	return ca;
1516 err:
1517 	bch2_dev_free(ca);
1518 	return NULL;
1519 }
1520 
1521 static void bch2_dev_attach(struct bch_fs *c, struct bch_dev *ca,
1522 			    unsigned dev_idx)
1523 {
1524 	ca->dev_idx = dev_idx;
1525 	__set_bit(ca->dev_idx, ca->self.d);
1526 
1527 	if (!ca->name[0])
1528 		scnprintf(ca->name, sizeof(ca->name), "dev-%u", dev_idx);
1529 
1530 	ca->fs = c;
1531 	rcu_assign_pointer(c->devs[ca->dev_idx], ca);
1532 
1533 	if (bch2_dev_sysfs_online(c, ca))
1534 		pr_warn("error creating sysfs objects");
1535 }
1536 
1537 static int bch2_dev_alloc(struct bch_fs *c, unsigned dev_idx)
1538 {
1539 	struct bch_member member = bch2_sb_member_get(c->disk_sb.sb, dev_idx);
1540 	struct bch_dev *ca = NULL;
1541 
1542 	if (bch2_fs_init_fault("dev_alloc"))
1543 		goto err;
1544 
1545 	ca = __bch2_dev_alloc(c, &member);
1546 	if (!ca)
1547 		goto err;
1548 
1549 	ca->fs = c;
1550 
1551 	bch2_dev_attach(c, ca, dev_idx);
1552 	return 0;
1553 err:
1554 	return bch_err_throw(c, ENOMEM_dev_alloc);
1555 }
1556 
1557 static int __bch2_dev_attach_bdev(struct bch_dev *ca, struct bch_sb_handle *sb)
1558 {
1559 	unsigned ret;
1560 
1561 	if (bch2_dev_is_online(ca)) {
1562 		bch_err(ca, "already have device online in slot %u",
1563 			sb->sb->dev_idx);
1564 		return bch_err_throw(ca->fs, device_already_online);
1565 	}
1566 
1567 	if (get_capacity(sb->bdev->bd_disk) <
1568 	    ca->mi.bucket_size * ca->mi.nbuckets) {
1569 		bch_err(ca, "cannot online: device too small");
1570 		return bch_err_throw(ca->fs, device_size_too_small);
1571 	}
1572 
1573 	BUG_ON(!enumerated_ref_is_zero(&ca->io_ref[READ]));
1574 	BUG_ON(!enumerated_ref_is_zero(&ca->io_ref[WRITE]));
1575 
1576 	ret = bch2_dev_journal_init(ca, sb->sb);
1577 	if (ret)
1578 		return ret;
1579 
1580 	struct printbuf name = PRINTBUF;
1581 	prt_bdevname(&name, sb->bdev);
1582 	strscpy(ca->name, name.buf, sizeof(ca->name));
1583 	printbuf_exit(&name);
1584 
1585 	/* Commit: */
1586 	ca->disk_sb = *sb;
1587 	memset(sb, 0, sizeof(*sb));
1588 
1589 	/*
1590 	 * Stash pointer to the filesystem for blk_holder_ops - note that once
1591 	 * attached to a filesystem, we will always close the block device
1592 	 * before tearing down the filesystem object.
1593 	 */
1594 	ca->disk_sb.holder->c = ca->fs;
1595 
1596 	ca->dev = ca->disk_sb.bdev->bd_dev;
1597 
1598 	enumerated_ref_start(&ca->io_ref[READ]);
1599 
1600 	return 0;
1601 }
1602 
1603 static int bch2_dev_attach_bdev(struct bch_fs *c, struct bch_sb_handle *sb)
1604 {
1605 	struct bch_dev *ca;
1606 	int ret;
1607 
1608 	lockdep_assert_held(&c->state_lock);
1609 
1610 	if (le64_to_cpu(sb->sb->seq) >
1611 	    le64_to_cpu(c->disk_sb.sb->seq))
1612 		bch2_sb_to_fs(c, sb->sb);
1613 
1614 	BUG_ON(!bch2_dev_exists(c, sb->sb->dev_idx));
1615 
1616 	ca = bch2_dev_locked(c, sb->sb->dev_idx);
1617 
1618 	ret = __bch2_dev_attach_bdev(ca, sb);
1619 	if (ret)
1620 		return ret;
1621 
1622 	set_bit(ca->dev_idx, c->online_devs.d);
1623 
1624 	bch2_dev_sysfs_online(c, ca);
1625 
1626 	bch2_rebalance_wakeup(c);
1627 	return 0;
1628 }
1629 
1630 /* Device management: */
1631 
1632 /*
1633  * Note: this function is also used by the error paths - when a particular
1634  * device sees an error, we call it to determine whether we can just set the
1635  * device RO, or - if this function returns false - we'll set the whole
1636  * filesystem RO:
1637  *
1638  * XXX: maybe we should be more explicit about whether we're changing state
1639  * because we got an error or what have you?
1640  */
1641 bool bch2_dev_state_allowed(struct bch_fs *c, struct bch_dev *ca,
1642 			    enum bch_member_state new_state, int flags)
1643 {
1644 	struct bch_devs_mask new_online_devs;
1645 	int nr_rw = 0, required;
1646 
1647 	lockdep_assert_held(&c->state_lock);
1648 
1649 	switch (new_state) {
1650 	case BCH_MEMBER_STATE_rw:
1651 		return true;
1652 	case BCH_MEMBER_STATE_ro:
1653 		if (ca->mi.state != BCH_MEMBER_STATE_rw)
1654 			return true;
1655 
1656 		/* do we have enough devices to write to?  */
1657 		for_each_member_device(c, ca2)
1658 			if (ca2 != ca)
1659 				nr_rw += ca2->mi.state == BCH_MEMBER_STATE_rw;
1660 
1661 		required = max(!(flags & BCH_FORCE_IF_METADATA_DEGRADED)
1662 			       ? c->opts.metadata_replicas
1663 			       : metadata_replicas_required(c),
1664 			       !(flags & BCH_FORCE_IF_DATA_DEGRADED)
1665 			       ? c->opts.data_replicas
1666 			       : data_replicas_required(c));
1667 
1668 		return nr_rw >= required;
1669 	case BCH_MEMBER_STATE_failed:
1670 	case BCH_MEMBER_STATE_spare:
1671 		if (ca->mi.state != BCH_MEMBER_STATE_rw &&
1672 		    ca->mi.state != BCH_MEMBER_STATE_ro)
1673 			return true;
1674 
1675 		/* do we have enough devices to read from?  */
1676 		new_online_devs = c->online_devs;
1677 		__clear_bit(ca->dev_idx, new_online_devs.d);
1678 
1679 		return bch2_have_enough_devs(c, new_online_devs, flags, false);
1680 	default:
1681 		BUG();
1682 	}
1683 }
1684 
1685 static void __bch2_dev_read_only(struct bch_fs *c, struct bch_dev *ca)
1686 {
1687 	bch2_dev_io_ref_stop(ca, WRITE);
1688 
1689 	/*
1690 	 * The allocator thread itself allocates btree nodes, so stop it first:
1691 	 */
1692 	bch2_dev_allocator_remove(c, ca);
1693 	bch2_recalc_capacity(c);
1694 	bch2_dev_journal_stop(&c->journal, ca);
1695 }
1696 
1697 static void __bch2_dev_read_write(struct bch_fs *c, struct bch_dev *ca)
1698 {
1699 	lockdep_assert_held(&c->state_lock);
1700 
1701 	BUG_ON(ca->mi.state != BCH_MEMBER_STATE_rw);
1702 
1703 	bch2_dev_allocator_add(c, ca);
1704 	bch2_recalc_capacity(c);
1705 
1706 	if (enumerated_ref_is_zero(&ca->io_ref[WRITE]))
1707 		enumerated_ref_start(&ca->io_ref[WRITE]);
1708 
1709 	bch2_dev_do_discards(ca);
1710 }
1711 
1712 int __bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1713 			 enum bch_member_state new_state, int flags)
1714 {
1715 	struct bch_member *m;
1716 	int ret = 0;
1717 
1718 	if (ca->mi.state == new_state)
1719 		return 0;
1720 
1721 	if (!bch2_dev_state_allowed(c, ca, new_state, flags))
1722 		return bch_err_throw(c, device_state_not_allowed);
1723 
1724 	if (new_state != BCH_MEMBER_STATE_rw)
1725 		__bch2_dev_read_only(c, ca);
1726 
1727 	bch_notice(ca, "%s", bch2_member_states[new_state]);
1728 
1729 	mutex_lock(&c->sb_lock);
1730 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
1731 	SET_BCH_MEMBER_STATE(m, new_state);
1732 	bch2_write_super(c);
1733 	mutex_unlock(&c->sb_lock);
1734 
1735 	if (new_state == BCH_MEMBER_STATE_rw)
1736 		__bch2_dev_read_write(c, ca);
1737 
1738 	bch2_rebalance_wakeup(c);
1739 
1740 	return ret;
1741 }
1742 
1743 int bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1744 		       enum bch_member_state new_state, int flags)
1745 {
1746 	int ret;
1747 
1748 	down_write(&c->state_lock);
1749 	ret = __bch2_dev_set_state(c, ca, new_state, flags);
1750 	up_write(&c->state_lock);
1751 
1752 	return ret;
1753 }
1754 
1755 /* Device add/removal: */
1756 
1757 int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
1758 {
1759 	struct bch_member *m;
1760 	unsigned dev_idx = ca->dev_idx, data;
1761 	bool fast_device_removal = !bch2_request_incompat_feature(c,
1762 					bcachefs_metadata_version_fast_device_removal);
1763 	int ret;
1764 
1765 	down_write(&c->state_lock);
1766 
1767 	/*
1768 	 * We consume a reference to ca->ref, regardless of whether we succeed
1769 	 * or fail:
1770 	 */
1771 	bch2_dev_put(ca);
1772 
1773 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1774 		bch_err(ca, "Cannot remove without losing data");
1775 		ret = bch_err_throw(c, device_state_not_allowed);
1776 		goto err;
1777 	}
1778 
1779 	__bch2_dev_read_only(c, ca);
1780 
1781 	ret = fast_device_removal
1782 		? bch2_dev_data_drop_by_backpointers(c, ca->dev_idx, flags)
1783 		: (bch2_dev_data_drop(c, ca->dev_idx, flags) ?:
1784 		   bch2_dev_remove_stripes(c, ca->dev_idx, flags));
1785 	if (ret)
1786 		goto err;
1787 
1788 	/* Check if device still has data before blowing away alloc info */
1789 	struct bch_dev_usage usage = bch2_dev_usage_read(ca);
1790 	for (unsigned i = 0; i < BCH_DATA_NR; i++)
1791 		if (!data_type_is_empty(i) &&
1792 		    !data_type_is_hidden(i) &&
1793 		    usage.buckets[i]) {
1794 			bch_err(ca, "Remove failed: still has data (%s, %llu buckets)",
1795 				__bch2_data_types[i], usage.buckets[i]);
1796 			ret = -EBUSY;
1797 			goto err;
1798 		}
1799 
1800 	ret = bch2_dev_remove_alloc(c, ca);
1801 	bch_err_msg(ca, ret, "bch2_dev_remove_alloc()");
1802 	if (ret)
1803 		goto err;
1804 
1805 	/*
1806 	 * We need to flush the entire journal to get rid of keys that reference
1807 	 * the device being removed before removing the superblock entry
1808 	 */
1809 	bch2_journal_flush_all_pins(&c->journal);
1810 
1811 	/*
1812 	 * this is really just needed for the bch2_replicas_gc_(start|end)
1813 	 * calls, and could be cleaned up:
1814 	 */
1815 	ret = bch2_journal_flush_device_pins(&c->journal, ca->dev_idx);
1816 	bch_err_msg(ca, ret, "bch2_journal_flush_device_pins()");
1817 	if (ret)
1818 		goto err;
1819 
1820 	ret = bch2_journal_flush(&c->journal);
1821 	bch_err_msg(ca, ret, "bch2_journal_flush()");
1822 	if (ret)
1823 		goto err;
1824 
1825 	ret = bch2_replicas_gc2(c);
1826 	bch_err_msg(ca, ret, "bch2_replicas_gc2()");
1827 	if (ret)
1828 		goto err;
1829 
1830 	data = bch2_dev_has_data(c, ca);
1831 	if (data) {
1832 		struct printbuf data_has = PRINTBUF;
1833 
1834 		prt_bitflags(&data_has, __bch2_data_types, data);
1835 		bch_err(ca, "Remove failed, still has data (%s)", data_has.buf);
1836 		printbuf_exit(&data_has);
1837 		ret = -EBUSY;
1838 		goto err;
1839 	}
1840 
1841 	__bch2_dev_offline(c, ca);
1842 
1843 	mutex_lock(&c->sb_lock);
1844 	rcu_assign_pointer(c->devs[ca->dev_idx], NULL);
1845 	mutex_unlock(&c->sb_lock);
1846 
1847 #ifndef CONFIG_BCACHEFS_DEBUG
1848 	percpu_ref_kill(&ca->ref);
1849 #else
1850 	ca->dying = true;
1851 	bch2_dev_put(ca);
1852 #endif
1853 	wait_for_completion(&ca->ref_completion);
1854 
1855 	bch2_dev_free(ca);
1856 
1857 	/*
1858 	 * Free this device's slot in the bch_member array - all pointers to
1859 	 * this device must be gone:
1860 	 */
1861 	mutex_lock(&c->sb_lock);
1862 	m = bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx);
1863 
1864 	if (fast_device_removal)
1865 		m->uuid = BCH_SB_MEMBER_DELETED_UUID;
1866 	else
1867 		memset(&m->uuid, 0, sizeof(m->uuid));
1868 
1869 	bch2_write_super(c);
1870 
1871 	mutex_unlock(&c->sb_lock);
1872 	up_write(&c->state_lock);
1873 	return 0;
1874 err:
1875 	if (test_bit(BCH_FS_rw, &c->flags) &&
1876 	    ca->mi.state == BCH_MEMBER_STATE_rw &&
1877 	    !enumerated_ref_is_zero(&ca->io_ref[READ]))
1878 		__bch2_dev_read_write(c, ca);
1879 	up_write(&c->state_lock);
1880 	return ret;
1881 }
1882 
1883 /* Add new device to running filesystem: */
1884 int bch2_dev_add(struct bch_fs *c, const char *path)
1885 {
1886 	struct bch_opts opts = bch2_opts_empty();
1887 	struct bch_sb_handle sb = {};
1888 	struct bch_dev *ca = NULL;
1889 	struct printbuf errbuf = PRINTBUF;
1890 	struct printbuf label = PRINTBUF;
1891 	int ret = 0;
1892 
1893 	ret = bch2_read_super(path, &opts, &sb);
1894 	bch_err_msg(c, ret, "reading super");
1895 	if (ret)
1896 		goto err;
1897 
1898 	struct bch_member dev_mi = bch2_sb_member_get(sb.sb, sb.sb->dev_idx);
1899 
1900 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1901 		bch2_disk_path_to_text_sb(&label, sb.sb, BCH_MEMBER_GROUP(&dev_mi) - 1);
1902 		if (label.allocation_failure) {
1903 			ret = -ENOMEM;
1904 			goto err;
1905 		}
1906 	}
1907 
1908 	if (list_empty(&c->list)) {
1909 		mutex_lock(&bch_fs_list_lock);
1910 		if (__bch2_uuid_to_fs(c->sb.uuid))
1911 			ret = bch_err_throw(c, filesystem_uuid_already_open);
1912 		else
1913 			list_add(&c->list, &bch_fs_list);
1914 		mutex_unlock(&bch_fs_list_lock);
1915 
1916 		if (ret) {
1917 			bch_err(c, "filesystem UUID already open");
1918 			goto err;
1919 		}
1920 	}
1921 
1922 	ret = bch2_dev_may_add(sb.sb, c);
1923 	if (ret)
1924 		goto err;
1925 
1926 	ca = __bch2_dev_alloc(c, &dev_mi);
1927 	if (!ca) {
1928 		ret = -ENOMEM;
1929 		goto err;
1930 	}
1931 
1932 	ret = __bch2_dev_attach_bdev(ca, &sb);
1933 	if (ret)
1934 		goto err;
1935 
1936 	down_write(&c->state_lock);
1937 	mutex_lock(&c->sb_lock);
1938 	SET_BCH_SB_MULTI_DEVICE(c->disk_sb.sb, true);
1939 
1940 	ret = bch2_sb_from_fs(c, ca);
1941 	bch_err_msg(c, ret, "setting up new superblock");
1942 	if (ret)
1943 		goto err_unlock;
1944 
1945 	if (dynamic_fault("bcachefs:add:no_slot"))
1946 		goto err_unlock;
1947 
1948 	ret = bch2_sb_member_alloc(c);
1949 	if (ret < 0) {
1950 		bch_err_msg(c, ret, "setting up new superblock");
1951 		goto err_unlock;
1952 	}
1953 	unsigned dev_idx = ret;
1954 	ret = 0;
1955 
1956 	/* success: */
1957 
1958 	dev_mi.last_mount = cpu_to_le64(ktime_get_real_seconds());
1959 	*bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx) = dev_mi;
1960 
1961 	ca->disk_sb.sb->dev_idx	= dev_idx;
1962 	bch2_dev_attach(c, ca, dev_idx);
1963 
1964 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1965 		ret = __bch2_dev_group_set(c, ca, label.buf);
1966 		bch_err_msg(c, ret, "creating new label");
1967 		if (ret)
1968 			goto err_unlock;
1969 	}
1970 
1971 	bch2_write_super(c);
1972 	mutex_unlock(&c->sb_lock);
1973 
1974 	if (test_bit(BCH_FS_started, &c->flags)) {
1975 		ret = bch2_dev_usage_init(ca, false);
1976 		if (ret)
1977 			goto err_late;
1978 
1979 		ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1980 		bch_err_msg(ca, ret, "marking new superblock");
1981 		if (ret)
1982 			goto err_late;
1983 
1984 		ret = bch2_fs_freespace_init(c);
1985 		bch_err_msg(ca, ret, "initializing free space");
1986 		if (ret)
1987 			goto err_late;
1988 
1989 		if (ca->mi.state == BCH_MEMBER_STATE_rw)
1990 			__bch2_dev_read_write(c, ca);
1991 
1992 		ret = bch2_dev_journal_alloc(ca, false);
1993 		bch_err_msg(c, ret, "allocating journal");
1994 		if (ret)
1995 			goto err_late;
1996 	}
1997 
1998 	up_write(&c->state_lock);
1999 out:
2000 	printbuf_exit(&label);
2001 	printbuf_exit(&errbuf);
2002 	bch_err_fn(c, ret);
2003 	return ret;
2004 
2005 err_unlock:
2006 	mutex_unlock(&c->sb_lock);
2007 	up_write(&c->state_lock);
2008 err:
2009 	if (ca)
2010 		bch2_dev_free(ca);
2011 	bch2_free_super(&sb);
2012 	goto out;
2013 err_late:
2014 	up_write(&c->state_lock);
2015 	ca = NULL;
2016 	goto err;
2017 }
2018 
2019 /* Hot add existing device to running filesystem: */
2020 int bch2_dev_online(struct bch_fs *c, const char *path)
2021 {
2022 	struct bch_opts opts = bch2_opts_empty();
2023 	struct bch_sb_handle sb = { NULL };
2024 	struct bch_dev *ca;
2025 	unsigned dev_idx;
2026 	int ret;
2027 
2028 	down_write(&c->state_lock);
2029 
2030 	ret = bch2_read_super(path, &opts, &sb);
2031 	if (ret) {
2032 		up_write(&c->state_lock);
2033 		return ret;
2034 	}
2035 
2036 	dev_idx = sb.sb->dev_idx;
2037 
2038 	ret = bch2_dev_in_fs(&c->disk_sb, &sb, &c->opts);
2039 	bch_err_msg(c, ret, "bringing %s online", path);
2040 	if (ret)
2041 		goto err;
2042 
2043 	ret = bch2_dev_attach_bdev(c, &sb);
2044 	if (ret)
2045 		goto err;
2046 
2047 	ca = bch2_dev_locked(c, dev_idx);
2048 
2049 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
2050 	bch_err_msg(c, ret, "bringing %s online: error from bch2_trans_mark_dev_sb", path);
2051 	if (ret)
2052 		goto err;
2053 
2054 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
2055 		__bch2_dev_read_write(c, ca);
2056 
2057 	if (!ca->mi.freespace_initialized) {
2058 		ret = bch2_dev_freespace_init(c, ca, 0, ca->mi.nbuckets);
2059 		bch_err_msg(ca, ret, "initializing free space");
2060 		if (ret)
2061 			goto err;
2062 	}
2063 
2064 	if (!ca->journal.nr) {
2065 		ret = bch2_dev_journal_alloc(ca, false);
2066 		bch_err_msg(ca, ret, "allocating journal");
2067 		if (ret)
2068 			goto err;
2069 	}
2070 
2071 	mutex_lock(&c->sb_lock);
2072 	bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount =
2073 		cpu_to_le64(ktime_get_real_seconds());
2074 	bch2_write_super(c);
2075 	mutex_unlock(&c->sb_lock);
2076 
2077 	up_write(&c->state_lock);
2078 	return 0;
2079 err:
2080 	up_write(&c->state_lock);
2081 	bch2_free_super(&sb);
2082 	return ret;
2083 }
2084 
2085 int bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca, int flags)
2086 {
2087 	down_write(&c->state_lock);
2088 
2089 	if (!bch2_dev_is_online(ca)) {
2090 		bch_err(ca, "Already offline");
2091 		up_write(&c->state_lock);
2092 		return 0;
2093 	}
2094 
2095 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
2096 		bch_err(ca, "Cannot offline required disk");
2097 		up_write(&c->state_lock);
2098 		return bch_err_throw(c, device_state_not_allowed);
2099 	}
2100 
2101 	__bch2_dev_offline(c, ca);
2102 
2103 	up_write(&c->state_lock);
2104 	return 0;
2105 }
2106 
2107 static int __bch2_dev_resize_alloc(struct bch_dev *ca, u64 old_nbuckets, u64 new_nbuckets)
2108 {
2109 	struct bch_fs *c = ca->fs;
2110 	u64 v[3] = { new_nbuckets - old_nbuckets, 0, 0 };
2111 
2112 	return bch2_trans_commit_do(ca->fs, NULL, NULL, 0,
2113 			bch2_disk_accounting_mod2(trans, false, v, dev_data_type,
2114 						  .dev = ca->dev_idx,
2115 						  .data_type = BCH_DATA_free)) ?:
2116 		bch2_dev_freespace_init(c, ca, old_nbuckets, new_nbuckets);
2117 }
2118 
2119 int bch2_dev_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
2120 {
2121 	struct bch_member *m;
2122 	u64 old_nbuckets;
2123 	int ret = 0;
2124 
2125 	down_write(&c->state_lock);
2126 	old_nbuckets = ca->mi.nbuckets;
2127 
2128 	if (nbuckets < ca->mi.nbuckets) {
2129 		bch_err(ca, "Cannot shrink yet");
2130 		ret = -EINVAL;
2131 		goto err;
2132 	}
2133 
2134 	if (nbuckets > BCH_MEMBER_NBUCKETS_MAX) {
2135 		bch_err(ca, "New device size too big (%llu greater than max %u)",
2136 			nbuckets, BCH_MEMBER_NBUCKETS_MAX);
2137 		ret = bch_err_throw(c, device_size_too_big);
2138 		goto err;
2139 	}
2140 
2141 	if (bch2_dev_is_online(ca) &&
2142 	    get_capacity(ca->disk_sb.bdev->bd_disk) <
2143 	    ca->mi.bucket_size * nbuckets) {
2144 		bch_err(ca, "New size larger than device");
2145 		ret = bch_err_throw(c, device_size_too_small);
2146 		goto err;
2147 	}
2148 
2149 	ret = bch2_dev_buckets_resize(c, ca, nbuckets);
2150 	bch_err_msg(ca, ret, "resizing buckets");
2151 	if (ret)
2152 		goto err;
2153 
2154 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
2155 	if (ret)
2156 		goto err;
2157 
2158 	mutex_lock(&c->sb_lock);
2159 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
2160 	m->nbuckets = cpu_to_le64(nbuckets);
2161 
2162 	bch2_write_super(c);
2163 	mutex_unlock(&c->sb_lock);
2164 
2165 	if (ca->mi.freespace_initialized) {
2166 		ret = __bch2_dev_resize_alloc(ca, old_nbuckets, nbuckets);
2167 		if (ret)
2168 			goto err;
2169 	}
2170 
2171 	bch2_recalc_capacity(c);
2172 err:
2173 	up_write(&c->state_lock);
2174 	return ret;
2175 }
2176 
2177 int bch2_fs_resize_on_mount(struct bch_fs *c)
2178 {
2179 	for_each_online_member(c, ca, BCH_DEV_READ_REF_fs_resize_on_mount) {
2180 		u64 old_nbuckets = ca->mi.nbuckets;
2181 		u64 new_nbuckets = div64_u64(get_capacity(ca->disk_sb.bdev->bd_disk),
2182 					 ca->mi.bucket_size);
2183 
2184 		if (ca->mi.resize_on_mount &&
2185 		    new_nbuckets > ca->mi.nbuckets) {
2186 			bch_info(ca, "resizing to size %llu", new_nbuckets * ca->mi.bucket_size);
2187 			int ret = bch2_dev_buckets_resize(c, ca, new_nbuckets);
2188 			bch_err_fn(ca, ret);
2189 			if (ret) {
2190 				enumerated_ref_put(&ca->io_ref[READ],
2191 						   BCH_DEV_READ_REF_fs_resize_on_mount);
2192 				up_write(&c->state_lock);
2193 				return ret;
2194 			}
2195 
2196 			mutex_lock(&c->sb_lock);
2197 			struct bch_member *m =
2198 				bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
2199 			m->nbuckets = cpu_to_le64(new_nbuckets);
2200 			SET_BCH_MEMBER_RESIZE_ON_MOUNT(m, false);
2201 
2202 			c->disk_sb.sb->features[0] &= ~cpu_to_le64(BIT_ULL(BCH_FEATURE_small_image));
2203 			bch2_write_super(c);
2204 			mutex_unlock(&c->sb_lock);
2205 
2206 			if (ca->mi.freespace_initialized) {
2207 				ret = __bch2_dev_resize_alloc(ca, old_nbuckets, new_nbuckets);
2208 				if (ret) {
2209 					enumerated_ref_put(&ca->io_ref[READ],
2210 							BCH_DEV_READ_REF_fs_resize_on_mount);
2211 					up_write(&c->state_lock);
2212 					return ret;
2213 				}
2214 			}
2215 		}
2216 	}
2217 	return 0;
2218 }
2219 
2220 /* return with ref on ca->ref: */
2221 struct bch_dev *bch2_dev_lookup(struct bch_fs *c, const char *name)
2222 {
2223 	if (!strncmp(name, "/dev/", strlen("/dev/")))
2224 		name += strlen("/dev/");
2225 
2226 	for_each_member_device(c, ca)
2227 		if (!strcmp(name, ca->name))
2228 			return ca;
2229 	return ERR_PTR(-BCH_ERR_ENOENT_dev_not_found);
2230 }
2231 
2232 /* blk_holder_ops: */
2233 
2234 static struct bch_fs *bdev_get_fs(struct block_device *bdev)
2235 	__releases(&bdev->bd_holder_lock)
2236 {
2237 	struct bch_sb_handle_holder *holder = bdev->bd_holder;
2238 	struct bch_fs *c = holder->c;
2239 
2240 	if (c && !bch2_ro_ref_tryget(c))
2241 		c = NULL;
2242 
2243 	mutex_unlock(&bdev->bd_holder_lock);
2244 
2245 	if (c)
2246 		wait_event(c->ro_ref_wait, test_bit(BCH_FS_started, &c->flags));
2247 	return c;
2248 }
2249 
2250 /* returns with ref on ca->ref */
2251 static struct bch_dev *bdev_to_bch_dev(struct bch_fs *c, struct block_device *bdev)
2252 {
2253 	for_each_member_device(c, ca)
2254 		if (ca->disk_sb.bdev == bdev)
2255 			return ca;
2256 	return NULL;
2257 }
2258 
2259 static void bch2_fs_bdev_mark_dead(struct block_device *bdev, bool surprise)
2260 {
2261 	struct bch_fs *c = bdev_get_fs(bdev);
2262 	if (!c)
2263 		return;
2264 
2265 	struct super_block *sb = c->vfs_sb;
2266 	if (sb) {
2267 		/*
2268 		 * Not necessary, c->ro_ref guards against the filesystem being
2269 		 * unmounted - we only take this to avoid a warning in
2270 		 * sync_filesystem:
2271 		 */
2272 		down_read(&sb->s_umount);
2273 	}
2274 
2275 	down_write(&c->state_lock);
2276 	struct bch_dev *ca = bdev_to_bch_dev(c, bdev);
2277 	if (!ca)
2278 		goto unlock;
2279 
2280 	bool dev = bch2_dev_state_allowed(c, ca,
2281 					  BCH_MEMBER_STATE_failed,
2282 					  BCH_FORCE_IF_DEGRADED);
2283 
2284 	if (!dev && sb) {
2285 		if (!surprise)
2286 			sync_filesystem(sb);
2287 		shrink_dcache_sb(sb);
2288 		evict_inodes(sb);
2289 	}
2290 
2291 	struct printbuf buf = PRINTBUF;
2292 	__bch2_log_msg_start(ca->name, &buf);
2293 
2294 	prt_printf(&buf, "offline from block layer");
2295 
2296 	if (dev) {
2297 		__bch2_dev_offline(c, ca);
2298 	} else {
2299 		bch2_journal_flush(&c->journal);
2300 		bch2_fs_emergency_read_only2(c, &buf);
2301 	}
2302 
2303 	bch2_print_str(c, KERN_ERR, buf.buf);
2304 	printbuf_exit(&buf);
2305 
2306 	bch2_dev_put(ca);
2307 unlock:
2308 	if (sb)
2309 		up_read(&sb->s_umount);
2310 	up_write(&c->state_lock);
2311 	bch2_ro_ref_put(c);
2312 }
2313 
2314 static void bch2_fs_bdev_sync(struct block_device *bdev)
2315 {
2316 	struct bch_fs *c = bdev_get_fs(bdev);
2317 	if (!c)
2318 		return;
2319 
2320 	struct super_block *sb = c->vfs_sb;
2321 	if (sb) {
2322 		/*
2323 		 * Not necessary, c->ro_ref guards against the filesystem being
2324 		 * unmounted - we only take this to avoid a warning in
2325 		 * sync_filesystem:
2326 		 */
2327 		down_read(&sb->s_umount);
2328 		sync_filesystem(sb);
2329 		up_read(&sb->s_umount);
2330 	}
2331 
2332 	bch2_ro_ref_put(c);
2333 }
2334 
2335 const struct blk_holder_ops bch2_sb_handle_bdev_ops = {
2336 	.mark_dead		= bch2_fs_bdev_mark_dead,
2337 	.sync			= bch2_fs_bdev_sync,
2338 };
2339 
2340 /* Filesystem open: */
2341 
2342 static inline int sb_cmp(struct bch_sb *l, struct bch_sb *r)
2343 {
2344 	return  cmp_int(le64_to_cpu(l->seq), le64_to_cpu(r->seq)) ?:
2345 		cmp_int(le64_to_cpu(l->write_time), le64_to_cpu(r->write_time));
2346 }
2347 
2348 struct bch_fs *bch2_fs_open(darray_const_str *devices,
2349 			    struct bch_opts *opts)
2350 {
2351 	bch_sb_handles sbs = {};
2352 	struct bch_fs *c = NULL;
2353 	struct bch_sb_handle *best = NULL;
2354 	struct printbuf errbuf = PRINTBUF;
2355 	int ret = 0;
2356 
2357 	if (!try_module_get(THIS_MODULE))
2358 		return ERR_PTR(-ENODEV);
2359 
2360 	if (!devices->nr) {
2361 		ret = -EINVAL;
2362 		goto err;
2363 	}
2364 
2365 	ret = darray_make_room(&sbs, devices->nr);
2366 	if (ret)
2367 		goto err;
2368 
2369 	darray_for_each(*devices, i) {
2370 		struct bch_sb_handle sb = { NULL };
2371 
2372 		ret = bch2_read_super(*i, opts, &sb);
2373 		if (ret)
2374 			goto err;
2375 
2376 		BUG_ON(darray_push(&sbs, sb));
2377 	}
2378 
2379 	if (opts->nochanges && !opts->read_only) {
2380 		ret = bch_err_throw(c, erofs_nochanges);
2381 		goto err_print;
2382 	}
2383 
2384 	darray_for_each(sbs, sb)
2385 		if (!best || sb_cmp(sb->sb, best->sb) > 0)
2386 			best = sb;
2387 
2388 	darray_for_each_reverse(sbs, sb) {
2389 		ret = bch2_dev_in_fs(best, sb, opts);
2390 
2391 		if (ret == -BCH_ERR_device_has_been_removed ||
2392 		    ret == -BCH_ERR_device_splitbrain) {
2393 			bch2_free_super(sb);
2394 			darray_remove_item(&sbs, sb);
2395 			best -= best > sb;
2396 			ret = 0;
2397 			continue;
2398 		}
2399 
2400 		if (ret)
2401 			goto err_print;
2402 	}
2403 
2404 	c = bch2_fs_alloc(best->sb, opts, &sbs);
2405 	ret = PTR_ERR_OR_ZERO(c);
2406 	if (ret)
2407 		goto err;
2408 
2409 	down_write(&c->state_lock);
2410 	darray_for_each(sbs, sb) {
2411 		ret = bch2_dev_attach_bdev(c, sb);
2412 		if (ret) {
2413 			up_write(&c->state_lock);
2414 			goto err;
2415 		}
2416 	}
2417 	up_write(&c->state_lock);
2418 
2419 	if (!c->opts.nostart) {
2420 		ret = bch2_fs_start(c);
2421 		if (ret)
2422 			goto err;
2423 	}
2424 out:
2425 	darray_for_each(sbs, sb)
2426 		bch2_free_super(sb);
2427 	darray_exit(&sbs);
2428 	printbuf_exit(&errbuf);
2429 	module_put(THIS_MODULE);
2430 	return c;
2431 err_print:
2432 	pr_err("bch_fs_open err opening %s: %s",
2433 	       devices->data[0], bch2_err_str(ret));
2434 err:
2435 	if (!IS_ERR_OR_NULL(c))
2436 		bch2_fs_stop(c);
2437 	c = ERR_PTR(ret);
2438 	goto out;
2439 }
2440 
2441 /* Global interfaces/init */
2442 
2443 static void bcachefs_exit(void)
2444 {
2445 	bch2_debug_exit();
2446 	bch2_vfs_exit();
2447 	bch2_chardev_exit();
2448 	bch2_btree_key_cache_exit();
2449 	if (bcachefs_kset)
2450 		kset_unregister(bcachefs_kset);
2451 }
2452 
2453 static int __init bcachefs_init(void)
2454 {
2455 	bch2_bkey_pack_test();
2456 
2457 	if (!(bcachefs_kset = kset_create_and_add("bcachefs", NULL, fs_kobj)) ||
2458 	    bch2_btree_key_cache_init() ||
2459 	    bch2_chardev_init() ||
2460 	    bch2_vfs_init() ||
2461 	    bch2_debug_init())
2462 		goto err;
2463 
2464 	return 0;
2465 err:
2466 	bcachefs_exit();
2467 	return -ENOMEM;
2468 }
2469 
2470 #define BCH_DEBUG_PARAM(name, description) DEFINE_STATIC_KEY_FALSE(bch2_##name);
2471 BCH_DEBUG_PARAMS_ALL()
2472 #undef BCH_DEBUG_PARAM
2473 
2474 static int bch2_param_set_static_key_t(const char *val, const struct kernel_param *kp)
2475 {
2476 	/* Match bool exactly, by re-using it. */
2477 	struct static_key *key = kp->arg;
2478 	struct kernel_param boolkp = *kp;
2479 	bool v;
2480 	int ret;
2481 
2482 	boolkp.arg = &v;
2483 
2484 	ret = param_set_bool(val, &boolkp);
2485 	if (ret)
2486 		return ret;
2487 	if (v)
2488 		static_key_enable(key);
2489 	else
2490 		static_key_disable(key);
2491 	return 0;
2492 }
2493 
2494 static int bch2_param_get_static_key_t(char *buffer, const struct kernel_param *kp)
2495 {
2496 	struct static_key *key = kp->arg;
2497 	return sprintf(buffer, "%c\n", static_key_enabled(key) ? 'N' : 'Y');
2498 }
2499 
2500 static const struct kernel_param_ops bch2_param_ops_static_key_t = {
2501 	.flags = KERNEL_PARAM_OPS_FL_NOARG,
2502 	.set = bch2_param_set_static_key_t,
2503 	.get = bch2_param_get_static_key_t,
2504 };
2505 
2506 #define BCH_DEBUG_PARAM(name, description)				\
2507 	module_param_cb(name, &bch2_param_ops_static_key_t, &bch2_##name.key, 0644);\
2508 	__MODULE_PARM_TYPE(name, "static_key_t");			\
2509 	MODULE_PARM_DESC(name, description);
2510 BCH_DEBUG_PARAMS()
2511 #undef BCH_DEBUG_PARAM
2512 
2513 __maybe_unused
2514 static unsigned bch2_metadata_version = bcachefs_metadata_version_current;
2515 module_param_named(version, bch2_metadata_version, uint, 0444);
2516 
2517 module_exit(bcachefs_exit);
2518 module_init(bcachefs_init);
2519