xref: /linux/fs/bcachefs/super.c (revision f7f0adfe64de08803990dc4cbecd2849c04e314a)
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 "bkey_sort.h"
14 #include "btree_cache.h"
15 #include "btree_gc.h"
16 #include "btree_journal_iter.h"
17 #include "btree_key_cache.h"
18 #include "btree_node_scan.h"
19 #include "btree_update_interior.h"
20 #include "btree_io.h"
21 #include "btree_write_buffer.h"
22 #include "buckets_waiting_for_journal.h"
23 #include "chardev.h"
24 #include "checksum.h"
25 #include "clock.h"
26 #include "compress.h"
27 #include "debug.h"
28 #include "disk_accounting.h"
29 #include "disk_groups.h"
30 #include "ec.h"
31 #include "errcode.h"
32 #include "error.h"
33 #include "fs.h"
34 #include "fs-io.h"
35 #include "fs-io-buffered.h"
36 #include "fs-io-direct.h"
37 #include "fsck.h"
38 #include "inode.h"
39 #include "io_read.h"
40 #include "io_write.h"
41 #include "journal.h"
42 #include "journal_reclaim.h"
43 #include "journal_seq_blacklist.h"
44 #include "move.h"
45 #include "migrate.h"
46 #include "movinggc.h"
47 #include "nocow_locking.h"
48 #include "quota.h"
49 #include "rebalance.h"
50 #include "recovery.h"
51 #include "replicas.h"
52 #include "sb-clean.h"
53 #include "sb-counters.h"
54 #include "sb-errors.h"
55 #include "sb-members.h"
56 #include "snapshot.h"
57 #include "subvolume.h"
58 #include "super.h"
59 #include "super-io.h"
60 #include "sysfs.h"
61 #include "thread_with_file.h"
62 #include "trace.h"
63 
64 #include <linux/backing-dev.h>
65 #include <linux/blkdev.h>
66 #include <linux/debugfs.h>
67 #include <linux/device.h>
68 #include <linux/idr.h>
69 #include <linux/module.h>
70 #include <linux/percpu.h>
71 #include <linux/random.h>
72 #include <linux/sysfs.h>
73 #include <crypto/hash.h>
74 
75 MODULE_LICENSE("GPL");
76 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
77 MODULE_DESCRIPTION("bcachefs filesystem");
78 MODULE_SOFTDEP("pre: crc32c");
79 MODULE_SOFTDEP("pre: crc64");
80 MODULE_SOFTDEP("pre: sha256");
81 MODULE_SOFTDEP("pre: chacha20");
82 MODULE_SOFTDEP("pre: poly1305");
83 MODULE_SOFTDEP("pre: xxhash");
84 
85 const char * const bch2_fs_flag_strs[] = {
86 #define x(n)		#n,
87 	BCH_FS_FLAGS()
88 #undef x
89 	NULL
90 };
91 
92 void bch2_print_str(struct bch_fs *c, const char *str)
93 {
94 #ifdef __KERNEL__
95 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
96 
97 	if (unlikely(stdio)) {
98 		bch2_stdio_redirect_printf(stdio, true, "%s", str);
99 		return;
100 	}
101 #endif
102 	bch2_print_string_as_lines(KERN_ERR, str);
103 }
104 
105 __printf(2, 0)
106 static void bch2_print_maybe_redirect(struct stdio_redirect *stdio, const char *fmt, va_list args)
107 {
108 #ifdef __KERNEL__
109 	if (unlikely(stdio)) {
110 		if (fmt[0] == KERN_SOH[0])
111 			fmt += 2;
112 
113 		bch2_stdio_redirect_vprintf(stdio, true, fmt, args);
114 		return;
115 	}
116 #endif
117 	vprintk(fmt, args);
118 }
119 
120 void bch2_print_opts(struct bch_opts *opts, const char *fmt, ...)
121 {
122 	struct stdio_redirect *stdio = (void *)(unsigned long)opts->stdio;
123 
124 	va_list args;
125 	va_start(args, fmt);
126 	bch2_print_maybe_redirect(stdio, fmt, args);
127 	va_end(args);
128 }
129 
130 void __bch2_print(struct bch_fs *c, const char *fmt, ...)
131 {
132 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
133 
134 	va_list args;
135 	va_start(args, fmt);
136 	bch2_print_maybe_redirect(stdio, fmt, args);
137 	va_end(args);
138 }
139 
140 #define KTYPE(type)							\
141 static const struct attribute_group type ## _group = {			\
142 	.attrs = type ## _files						\
143 };									\
144 									\
145 static const struct attribute_group *type ## _groups[] = {		\
146 	&type ## _group,						\
147 	NULL								\
148 };									\
149 									\
150 static const struct kobj_type type ## _ktype = {			\
151 	.release	= type ## _release,				\
152 	.sysfs_ops	= &type ## _sysfs_ops,				\
153 	.default_groups = type ## _groups				\
154 }
155 
156 static void bch2_fs_release(struct kobject *);
157 static void bch2_dev_release(struct kobject *);
158 static void bch2_fs_counters_release(struct kobject *k)
159 {
160 }
161 
162 static void bch2_fs_internal_release(struct kobject *k)
163 {
164 }
165 
166 static void bch2_fs_opts_dir_release(struct kobject *k)
167 {
168 }
169 
170 static void bch2_fs_time_stats_release(struct kobject *k)
171 {
172 }
173 
174 KTYPE(bch2_fs);
175 KTYPE(bch2_fs_counters);
176 KTYPE(bch2_fs_internal);
177 KTYPE(bch2_fs_opts_dir);
178 KTYPE(bch2_fs_time_stats);
179 KTYPE(bch2_dev);
180 
181 static struct kset *bcachefs_kset;
182 static LIST_HEAD(bch_fs_list);
183 static DEFINE_MUTEX(bch_fs_list_lock);
184 
185 DECLARE_WAIT_QUEUE_HEAD(bch2_read_only_wait);
186 
187 static void bch2_dev_unlink(struct bch_dev *);
188 static void bch2_dev_free(struct bch_dev *);
189 static int bch2_dev_alloc(struct bch_fs *, unsigned);
190 static int bch2_dev_sysfs_online(struct bch_fs *, struct bch_dev *);
191 static void __bch2_dev_read_only(struct bch_fs *, struct bch_dev *);
192 
193 struct bch_fs *bch2_dev_to_fs(dev_t dev)
194 {
195 	struct bch_fs *c;
196 
197 	mutex_lock(&bch_fs_list_lock);
198 	rcu_read_lock();
199 
200 	list_for_each_entry(c, &bch_fs_list, list)
201 		for_each_member_device_rcu(c, ca, NULL)
202 			if (ca->disk_sb.bdev && ca->disk_sb.bdev->bd_dev == dev) {
203 				closure_get(&c->cl);
204 				goto found;
205 			}
206 	c = NULL;
207 found:
208 	rcu_read_unlock();
209 	mutex_unlock(&bch_fs_list_lock);
210 
211 	return c;
212 }
213 
214 static struct bch_fs *__bch2_uuid_to_fs(__uuid_t uuid)
215 {
216 	struct bch_fs *c;
217 
218 	lockdep_assert_held(&bch_fs_list_lock);
219 
220 	list_for_each_entry(c, &bch_fs_list, list)
221 		if (!memcmp(&c->disk_sb.sb->uuid, &uuid, sizeof(uuid)))
222 			return c;
223 
224 	return NULL;
225 }
226 
227 struct bch_fs *bch2_uuid_to_fs(__uuid_t uuid)
228 {
229 	struct bch_fs *c;
230 
231 	mutex_lock(&bch_fs_list_lock);
232 	c = __bch2_uuid_to_fs(uuid);
233 	if (c)
234 		closure_get(&c->cl);
235 	mutex_unlock(&bch_fs_list_lock);
236 
237 	return c;
238 }
239 
240 /* Filesystem RO/RW: */
241 
242 /*
243  * For startup/shutdown of RW stuff, the dependencies are:
244  *
245  * - foreground writes depend on copygc and rebalance (to free up space)
246  *
247  * - copygc and rebalance depend on mark and sweep gc (they actually probably
248  *   don't because they either reserve ahead of time or don't block if
249  *   allocations fail, but allocations can require mark and sweep gc to run
250  *   because of generation number wraparound)
251  *
252  * - all of the above depends on the allocator threads
253  *
254  * - allocator depends on the journal (when it rewrites prios and gens)
255  */
256 
257 static void __bch2_fs_read_only(struct bch_fs *c)
258 {
259 	unsigned clean_passes = 0;
260 	u64 seq = 0;
261 
262 	bch2_fs_ec_stop(c);
263 	bch2_open_buckets_stop(c, NULL, true);
264 	bch2_rebalance_stop(c);
265 	bch2_copygc_stop(c);
266 	bch2_fs_ec_flush(c);
267 
268 	bch_verbose(c, "flushing journal and stopping allocators, journal seq %llu",
269 		    journal_cur_seq(&c->journal));
270 
271 	do {
272 		clean_passes++;
273 
274 		if (bch2_btree_interior_updates_flush(c) ||
275 		    bch2_btree_write_buffer_flush_going_ro(c) ||
276 		    bch2_journal_flush_all_pins(&c->journal) ||
277 		    bch2_btree_flush_all_writes(c) ||
278 		    seq != atomic64_read(&c->journal.seq)) {
279 			seq = atomic64_read(&c->journal.seq);
280 			clean_passes = 0;
281 		}
282 	} while (clean_passes < 2);
283 
284 	bch_verbose(c, "flushing journal and stopping allocators complete, journal seq %llu",
285 		    journal_cur_seq(&c->journal));
286 
287 	if (test_bit(JOURNAL_replay_done, &c->journal.flags) &&
288 	    !test_bit(BCH_FS_emergency_ro, &c->flags))
289 		set_bit(BCH_FS_clean_shutdown, &c->flags);
290 
291 	bch2_fs_journal_stop(&c->journal);
292 
293 	bch_info(c, "%sclean shutdown complete, journal seq %llu",
294 		 test_bit(BCH_FS_clean_shutdown, &c->flags) ? "" : "un",
295 		 c->journal.seq_ondisk);
296 
297 	/*
298 	 * After stopping journal:
299 	 */
300 	for_each_member_device(c, ca)
301 		bch2_dev_allocator_remove(c, ca);
302 }
303 
304 #ifndef BCH_WRITE_REF_DEBUG
305 static void bch2_writes_disabled(struct percpu_ref *writes)
306 {
307 	struct bch_fs *c = container_of(writes, struct bch_fs, writes);
308 
309 	set_bit(BCH_FS_write_disable_complete, &c->flags);
310 	wake_up(&bch2_read_only_wait);
311 }
312 #endif
313 
314 void bch2_fs_read_only(struct bch_fs *c)
315 {
316 	if (!test_bit(BCH_FS_rw, &c->flags)) {
317 		bch2_journal_reclaim_stop(&c->journal);
318 		return;
319 	}
320 
321 	BUG_ON(test_bit(BCH_FS_write_disable_complete, &c->flags));
322 
323 	bch_verbose(c, "going read-only");
324 
325 	/*
326 	 * Block new foreground-end write operations from starting - any new
327 	 * writes will return -EROFS:
328 	 */
329 	set_bit(BCH_FS_going_ro, &c->flags);
330 #ifndef BCH_WRITE_REF_DEBUG
331 	percpu_ref_kill(&c->writes);
332 #else
333 	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++)
334 		bch2_write_ref_put(c, i);
335 #endif
336 
337 	/*
338 	 * If we're not doing an emergency shutdown, we want to wait on
339 	 * outstanding writes to complete so they don't see spurious errors due
340 	 * to shutting down the allocator:
341 	 *
342 	 * If we are doing an emergency shutdown outstanding writes may
343 	 * hang until we shutdown the allocator so we don't want to wait
344 	 * on outstanding writes before shutting everything down - but
345 	 * we do need to wait on them before returning and signalling
346 	 * that going RO is complete:
347 	 */
348 	wait_event(bch2_read_only_wait,
349 		   test_bit(BCH_FS_write_disable_complete, &c->flags) ||
350 		   test_bit(BCH_FS_emergency_ro, &c->flags));
351 
352 	bool writes_disabled = test_bit(BCH_FS_write_disable_complete, &c->flags);
353 	if (writes_disabled)
354 		bch_verbose(c, "finished waiting for writes to stop");
355 
356 	__bch2_fs_read_only(c);
357 
358 	wait_event(bch2_read_only_wait,
359 		   test_bit(BCH_FS_write_disable_complete, &c->flags));
360 
361 	if (!writes_disabled)
362 		bch_verbose(c, "finished waiting for writes to stop");
363 
364 	clear_bit(BCH_FS_write_disable_complete, &c->flags);
365 	clear_bit(BCH_FS_going_ro, &c->flags);
366 	clear_bit(BCH_FS_rw, &c->flags);
367 
368 	if (!bch2_journal_error(&c->journal) &&
369 	    !test_bit(BCH_FS_error, &c->flags) &&
370 	    !test_bit(BCH_FS_emergency_ro, &c->flags) &&
371 	    test_bit(BCH_FS_started, &c->flags) &&
372 	    test_bit(BCH_FS_clean_shutdown, &c->flags) &&
373 	    c->recovery_pass_done >= BCH_RECOVERY_PASS_journal_replay) {
374 		BUG_ON(c->journal.last_empty_seq != journal_cur_seq(&c->journal));
375 		BUG_ON(atomic_long_read(&c->btree_cache.nr_dirty));
376 		BUG_ON(atomic_long_read(&c->btree_key_cache.nr_dirty));
377 		BUG_ON(c->btree_write_buffer.inc.keys.nr);
378 		BUG_ON(c->btree_write_buffer.flushing.keys.nr);
379 		bch2_verify_accounting_clean(c);
380 
381 		bch_verbose(c, "marking filesystem clean");
382 		bch2_fs_mark_clean(c);
383 	} else {
384 		bch_verbose(c, "done going read-only, filesystem not clean");
385 	}
386 }
387 
388 static void bch2_fs_read_only_work(struct work_struct *work)
389 {
390 	struct bch_fs *c =
391 		container_of(work, struct bch_fs, read_only_work);
392 
393 	down_write(&c->state_lock);
394 	bch2_fs_read_only(c);
395 	up_write(&c->state_lock);
396 }
397 
398 static void bch2_fs_read_only_async(struct bch_fs *c)
399 {
400 	queue_work(system_long_wq, &c->read_only_work);
401 }
402 
403 bool bch2_fs_emergency_read_only(struct bch_fs *c)
404 {
405 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
406 
407 	bch2_journal_halt(&c->journal);
408 	bch2_fs_read_only_async(c);
409 
410 	wake_up(&bch2_read_only_wait);
411 	return ret;
412 }
413 
414 static int bch2_fs_read_write_late(struct bch_fs *c)
415 {
416 	int ret;
417 
418 	/*
419 	 * Data move operations can't run until after check_snapshots has
420 	 * completed, and bch2_snapshot_is_ancestor() is available.
421 	 *
422 	 * Ideally we'd start copygc/rebalance earlier instead of waiting for
423 	 * all of recovery/fsck to complete:
424 	 */
425 	ret = bch2_copygc_start(c);
426 	if (ret) {
427 		bch_err(c, "error starting copygc thread");
428 		return ret;
429 	}
430 
431 	ret = bch2_rebalance_start(c);
432 	if (ret) {
433 		bch_err(c, "error starting rebalance thread");
434 		return ret;
435 	}
436 
437 	return 0;
438 }
439 
440 static int __bch2_fs_read_write(struct bch_fs *c, bool early)
441 {
442 	int ret;
443 
444 	BUG_ON(!test_bit(BCH_FS_may_go_rw, &c->flags));
445 
446 	if (test_bit(BCH_FS_initial_gc_unfixed, &c->flags)) {
447 		bch_err(c, "cannot go rw, unfixed btree errors");
448 		return -BCH_ERR_erofs_unfixed_errors;
449 	}
450 
451 	if (test_bit(BCH_FS_rw, &c->flags))
452 		return 0;
453 
454 	bch_info(c, "going read-write");
455 
456 	ret = bch2_sb_members_v2_init(c);
457 	if (ret)
458 		goto err;
459 
460 	ret = bch2_fs_mark_dirty(c);
461 	if (ret)
462 		goto err;
463 
464 	clear_bit(BCH_FS_clean_shutdown, &c->flags);
465 
466 	/*
467 	 * First journal write must be a flush write: after a clean shutdown we
468 	 * don't read the journal, so the first journal write may end up
469 	 * overwriting whatever was there previously, and there must always be
470 	 * at least one non-flush write in the journal or recovery will fail:
471 	 */
472 	set_bit(JOURNAL_need_flush_write, &c->journal.flags);
473 	set_bit(JOURNAL_running, &c->journal.flags);
474 
475 	for_each_rw_member(c, ca)
476 		bch2_dev_allocator_add(c, ca);
477 	bch2_recalc_capacity(c);
478 
479 	set_bit(BCH_FS_rw, &c->flags);
480 	set_bit(BCH_FS_was_rw, &c->flags);
481 
482 #ifndef BCH_WRITE_REF_DEBUG
483 	percpu_ref_reinit(&c->writes);
484 #else
485 	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++) {
486 		BUG_ON(atomic_long_read(&c->writes[i]));
487 		atomic_long_inc(&c->writes[i]);
488 	}
489 #endif
490 
491 	ret = bch2_journal_reclaim_start(&c->journal);
492 	if (ret)
493 		goto err;
494 
495 	if (!early) {
496 		ret = bch2_fs_read_write_late(c);
497 		if (ret)
498 			goto err;
499 	}
500 
501 	bch2_do_discards(c);
502 	bch2_do_invalidates(c);
503 	bch2_do_stripe_deletes(c);
504 	bch2_do_pending_node_rewrites(c);
505 	return 0;
506 err:
507 	if (test_bit(BCH_FS_rw, &c->flags))
508 		bch2_fs_read_only(c);
509 	else
510 		__bch2_fs_read_only(c);
511 	return ret;
512 }
513 
514 int bch2_fs_read_write(struct bch_fs *c)
515 {
516 	if (c->opts.recovery_pass_last &&
517 	    c->opts.recovery_pass_last < BCH_RECOVERY_PASS_journal_replay)
518 		return -BCH_ERR_erofs_norecovery;
519 
520 	if (c->opts.nochanges)
521 		return -BCH_ERR_erofs_nochanges;
522 
523 	return __bch2_fs_read_write(c, false);
524 }
525 
526 int bch2_fs_read_write_early(struct bch_fs *c)
527 {
528 	lockdep_assert_held(&c->state_lock);
529 
530 	return __bch2_fs_read_write(c, true);
531 }
532 
533 /* Filesystem startup/shutdown: */
534 
535 static void __bch2_fs_free(struct bch_fs *c)
536 {
537 	for (unsigned i = 0; i < BCH_TIME_STAT_NR; i++)
538 		bch2_time_stats_exit(&c->times[i]);
539 
540 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
541 	bch2_free_pending_node_rewrites(c);
542 	bch2_fs_accounting_exit(c);
543 	bch2_fs_sb_errors_exit(c);
544 	bch2_fs_counters_exit(c);
545 	bch2_fs_snapshots_exit(c);
546 	bch2_fs_quota_exit(c);
547 	bch2_fs_fs_io_direct_exit(c);
548 	bch2_fs_fs_io_buffered_exit(c);
549 	bch2_fs_fsio_exit(c);
550 	bch2_fs_vfs_exit(c);
551 	bch2_fs_ec_exit(c);
552 	bch2_fs_encryption_exit(c);
553 	bch2_fs_nocow_locking_exit(c);
554 	bch2_fs_io_write_exit(c);
555 	bch2_fs_io_read_exit(c);
556 	bch2_fs_buckets_waiting_for_journal_exit(c);
557 	bch2_fs_btree_interior_update_exit(c);
558 	bch2_fs_btree_key_cache_exit(&c->btree_key_cache);
559 	bch2_fs_btree_cache_exit(c);
560 	bch2_fs_btree_iter_exit(c);
561 	bch2_fs_replicas_exit(c);
562 	bch2_fs_journal_exit(&c->journal);
563 	bch2_io_clock_exit(&c->io_clock[WRITE]);
564 	bch2_io_clock_exit(&c->io_clock[READ]);
565 	bch2_fs_compress_exit(c);
566 	bch2_fs_btree_gc_exit(c);
567 	bch2_journal_keys_put_initial(c);
568 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
569 	BUG_ON(atomic_read(&c->journal_keys.ref));
570 	bch2_fs_btree_write_buffer_exit(c);
571 	percpu_free_rwsem(&c->mark_lock);
572 	if (c->online_reserved) {
573 		u64 v = percpu_u64_get(c->online_reserved);
574 		WARN(v, "online_reserved not 0 at shutdown: %lli", v);
575 		free_percpu(c->online_reserved);
576 	}
577 
578 	darray_exit(&c->btree_roots_extra);
579 	free_percpu(c->pcpu);
580 	free_percpu(c->usage);
581 	mempool_exit(&c->large_bkey_pool);
582 	mempool_exit(&c->btree_bounce_pool);
583 	bioset_exit(&c->btree_bio);
584 	mempool_exit(&c->fill_iter);
585 #ifndef BCH_WRITE_REF_DEBUG
586 	percpu_ref_exit(&c->writes);
587 #endif
588 	kfree(rcu_dereference_protected(c->disk_groups, 1));
589 	kfree(c->journal_seq_blacklist_table);
590 
591 	if (c->write_ref_wq)
592 		destroy_workqueue(c->write_ref_wq);
593 	if (c->btree_write_submit_wq)
594 		destroy_workqueue(c->btree_write_submit_wq);
595 	if (c->btree_read_complete_wq)
596 		destroy_workqueue(c->btree_read_complete_wq);
597 	if (c->copygc_wq)
598 		destroy_workqueue(c->copygc_wq);
599 	if (c->btree_io_complete_wq)
600 		destroy_workqueue(c->btree_io_complete_wq);
601 	if (c->btree_update_wq)
602 		destroy_workqueue(c->btree_update_wq);
603 
604 	bch2_free_super(&c->disk_sb);
605 	kvfree(c);
606 	module_put(THIS_MODULE);
607 }
608 
609 static void bch2_fs_release(struct kobject *kobj)
610 {
611 	struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
612 
613 	__bch2_fs_free(c);
614 }
615 
616 void __bch2_fs_stop(struct bch_fs *c)
617 {
618 	bch_verbose(c, "shutting down");
619 
620 	set_bit(BCH_FS_stopping, &c->flags);
621 
622 	down_write(&c->state_lock);
623 	bch2_fs_read_only(c);
624 	up_write(&c->state_lock);
625 
626 	for_each_member_device(c, ca)
627 		bch2_dev_unlink(ca);
628 
629 	if (c->kobj.state_in_sysfs)
630 		kobject_del(&c->kobj);
631 
632 	bch2_fs_debug_exit(c);
633 	bch2_fs_chardev_exit(c);
634 
635 	bch2_ro_ref_put(c);
636 	wait_event(c->ro_ref_wait, !refcount_read(&c->ro_ref));
637 
638 	kobject_put(&c->counters_kobj);
639 	kobject_put(&c->time_stats);
640 	kobject_put(&c->opts_dir);
641 	kobject_put(&c->internal);
642 
643 	/* btree prefetch might have kicked off reads in the background: */
644 	bch2_btree_flush_all_reads(c);
645 
646 	for_each_member_device(c, ca)
647 		cancel_work_sync(&ca->io_error_work);
648 
649 	cancel_work_sync(&c->read_only_work);
650 }
651 
652 void bch2_fs_free(struct bch_fs *c)
653 {
654 	unsigned i;
655 
656 	mutex_lock(&bch_fs_list_lock);
657 	list_del(&c->list);
658 	mutex_unlock(&bch_fs_list_lock);
659 
660 	closure_sync(&c->cl);
661 	closure_debug_destroy(&c->cl);
662 
663 	for (i = 0; i < c->sb.nr_devices; i++) {
664 		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
665 
666 		if (ca) {
667 			EBUG_ON(atomic_long_read(&ca->ref) != 1);
668 			bch2_free_super(&ca->disk_sb);
669 			bch2_dev_free(ca);
670 		}
671 	}
672 
673 	bch_verbose(c, "shutdown complete");
674 
675 	kobject_put(&c->kobj);
676 }
677 
678 void bch2_fs_stop(struct bch_fs *c)
679 {
680 	__bch2_fs_stop(c);
681 	bch2_fs_free(c);
682 }
683 
684 static int bch2_fs_online(struct bch_fs *c)
685 {
686 	int ret = 0;
687 
688 	lockdep_assert_held(&bch_fs_list_lock);
689 
690 	if (__bch2_uuid_to_fs(c->sb.uuid)) {
691 		bch_err(c, "filesystem UUID already open");
692 		return -EINVAL;
693 	}
694 
695 	ret = bch2_fs_chardev_init(c);
696 	if (ret) {
697 		bch_err(c, "error creating character device");
698 		return ret;
699 	}
700 
701 	bch2_fs_debug_init(c);
702 
703 	ret = kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b) ?:
704 	    kobject_add(&c->internal, &c->kobj, "internal") ?:
705 	    kobject_add(&c->opts_dir, &c->kobj, "options") ?:
706 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
707 	    kobject_add(&c->time_stats, &c->kobj, "time_stats") ?:
708 #endif
709 	    kobject_add(&c->counters_kobj, &c->kobj, "counters") ?:
710 	    bch2_opts_create_sysfs_files(&c->opts_dir);
711 	if (ret) {
712 		bch_err(c, "error creating sysfs objects");
713 		return ret;
714 	}
715 
716 	down_write(&c->state_lock);
717 
718 	for_each_member_device(c, ca) {
719 		ret = bch2_dev_sysfs_online(c, ca);
720 		if (ret) {
721 			bch_err(c, "error creating sysfs objects");
722 			bch2_dev_put(ca);
723 			goto err;
724 		}
725 	}
726 
727 	BUG_ON(!list_empty(&c->list));
728 	list_add(&c->list, &bch_fs_list);
729 err:
730 	up_write(&c->state_lock);
731 	return ret;
732 }
733 
734 static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
735 {
736 	struct bch_fs *c;
737 	struct printbuf name = PRINTBUF;
738 	unsigned i, iter_size;
739 	int ret = 0;
740 
741 	c = kvmalloc(sizeof(struct bch_fs), GFP_KERNEL|__GFP_ZERO);
742 	if (!c) {
743 		c = ERR_PTR(-BCH_ERR_ENOMEM_fs_alloc);
744 		goto out;
745 	}
746 
747 	c->stdio = (void *)(unsigned long) opts.stdio;
748 
749 	__module_get(THIS_MODULE);
750 
751 	closure_init(&c->cl, NULL);
752 
753 	c->kobj.kset = bcachefs_kset;
754 	kobject_init(&c->kobj, &bch2_fs_ktype);
755 	kobject_init(&c->internal, &bch2_fs_internal_ktype);
756 	kobject_init(&c->opts_dir, &bch2_fs_opts_dir_ktype);
757 	kobject_init(&c->time_stats, &bch2_fs_time_stats_ktype);
758 	kobject_init(&c->counters_kobj, &bch2_fs_counters_ktype);
759 
760 	c->minor		= -1;
761 	c->disk_sb.fs_sb	= true;
762 
763 	init_rwsem(&c->state_lock);
764 	mutex_init(&c->sb_lock);
765 	mutex_init(&c->replicas_gc_lock);
766 	mutex_init(&c->btree_root_lock);
767 	INIT_WORK(&c->read_only_work, bch2_fs_read_only_work);
768 
769 	refcount_set(&c->ro_ref, 1);
770 	init_waitqueue_head(&c->ro_ref_wait);
771 	spin_lock_init(&c->recovery_pass_lock);
772 	sema_init(&c->online_fsck_mutex, 1);
773 
774 	for (i = 0; i < BCH_TIME_STAT_NR; i++)
775 		bch2_time_stats_init(&c->times[i]);
776 
777 	bch2_fs_copygc_init(c);
778 	bch2_fs_btree_key_cache_init_early(&c->btree_key_cache);
779 	bch2_fs_btree_iter_init_early(c);
780 	bch2_fs_btree_interior_update_init_early(c);
781 	bch2_fs_journal_keys_init(c);
782 	bch2_fs_allocator_background_init(c);
783 	bch2_fs_allocator_foreground_init(c);
784 	bch2_fs_rebalance_init(c);
785 	bch2_fs_quota_init(c);
786 	bch2_fs_ec_init_early(c);
787 	bch2_fs_move_init(c);
788 	bch2_fs_sb_errors_init_early(c);
789 
790 	INIT_LIST_HEAD(&c->list);
791 
792 	mutex_init(&c->bio_bounce_pages_lock);
793 	mutex_init(&c->snapshot_table_lock);
794 	init_rwsem(&c->snapshot_create_lock);
795 
796 	spin_lock_init(&c->btree_write_error_lock);
797 
798 	INIT_LIST_HEAD(&c->journal_iters);
799 
800 	INIT_LIST_HEAD(&c->fsck_error_msgs);
801 	mutex_init(&c->fsck_error_msgs_lock);
802 
803 	seqcount_init(&c->usage_lock);
804 
805 	sema_init(&c->io_in_flight, 128);
806 
807 	INIT_LIST_HEAD(&c->vfs_inodes_list);
808 	mutex_init(&c->vfs_inodes_lock);
809 
810 	c->journal.flush_write_time	= &c->times[BCH_TIME_journal_flush_write];
811 	c->journal.noflush_write_time	= &c->times[BCH_TIME_journal_noflush_write];
812 	c->journal.flush_seq_time	= &c->times[BCH_TIME_journal_flush_seq];
813 
814 	bch2_fs_btree_cache_init_early(&c->btree_cache);
815 
816 	mutex_init(&c->sectors_available_lock);
817 
818 	ret = percpu_init_rwsem(&c->mark_lock);
819 	if (ret)
820 		goto err;
821 
822 	mutex_lock(&c->sb_lock);
823 	ret = bch2_sb_to_fs(c, sb);
824 	mutex_unlock(&c->sb_lock);
825 
826 	if (ret)
827 		goto err;
828 
829 	pr_uuid(&name, c->sb.user_uuid.b);
830 	ret = name.allocation_failure ? -BCH_ERR_ENOMEM_fs_name_alloc : 0;
831 	if (ret)
832 		goto err;
833 
834 	strscpy(c->name, name.buf, sizeof(c->name));
835 	printbuf_exit(&name);
836 
837 	/* Compat: */
838 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
839 	    !BCH_SB_JOURNAL_FLUSH_DELAY(sb))
840 		SET_BCH_SB_JOURNAL_FLUSH_DELAY(sb, 1000);
841 
842 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
843 	    !BCH_SB_JOURNAL_RECLAIM_DELAY(sb))
844 		SET_BCH_SB_JOURNAL_RECLAIM_DELAY(sb, 100);
845 
846 	c->opts = bch2_opts_default;
847 	ret = bch2_opts_from_sb(&c->opts, sb);
848 	if (ret)
849 		goto err;
850 
851 	bch2_opts_apply(&c->opts, opts);
852 
853 	c->btree_key_cache_btrees |= 1U << BTREE_ID_alloc;
854 	if (c->opts.inodes_use_key_cache)
855 		c->btree_key_cache_btrees |= 1U << BTREE_ID_inodes;
856 	c->btree_key_cache_btrees |= 1U << BTREE_ID_logged_ops;
857 
858 	c->block_bits		= ilog2(block_sectors(c));
859 	c->btree_foreground_merge_threshold = BTREE_FOREGROUND_MERGE_THRESHOLD(c);
860 
861 	if (bch2_fs_init_fault("fs_alloc")) {
862 		bch_err(c, "fs_alloc fault injected");
863 		ret = -EFAULT;
864 		goto err;
865 	}
866 
867 	iter_size = sizeof(struct sort_iter) +
868 		(btree_blocks(c) + 1) * 2 *
869 		sizeof(struct sort_iter_set);
870 
871 	if (!(c->btree_update_wq = alloc_workqueue("bcachefs",
872 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_UNBOUND, 512)) ||
873 	    !(c->btree_io_complete_wq = alloc_workqueue("bcachefs_btree_io",
874 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
875 	    !(c->copygc_wq = alloc_workqueue("bcachefs_copygc",
876 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 1)) ||
877 	    !(c->btree_read_complete_wq = alloc_workqueue("bcachefs_btree_read_complete",
878 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 512)) ||
879 	    !(c->btree_write_submit_wq = alloc_workqueue("bcachefs_btree_write_sumit",
880 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
881 	    !(c->write_ref_wq = alloc_workqueue("bcachefs_write_ref",
882 				WQ_FREEZABLE, 0)) ||
883 #ifndef BCH_WRITE_REF_DEBUG
884 	    percpu_ref_init(&c->writes, bch2_writes_disabled,
885 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
886 #endif
887 	    mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
888 	    bioset_init(&c->btree_bio, 1,
889 			max(offsetof(struct btree_read_bio, bio),
890 			    offsetof(struct btree_write_bio, wbio.bio)),
891 			BIOSET_NEED_BVECS) ||
892 	    !(c->pcpu = alloc_percpu(struct bch_fs_pcpu)) ||
893 	    !(c->usage = alloc_percpu(struct bch_fs_usage_base)) ||
894 	    !(c->online_reserved = alloc_percpu(u64)) ||
895 	    mempool_init_kvmalloc_pool(&c->btree_bounce_pool, 1,
896 				       c->opts.btree_node_size) ||
897 	    mempool_init_kmalloc_pool(&c->large_bkey_pool, 1, 2048)) {
898 		ret = -BCH_ERR_ENOMEM_fs_other_alloc;
899 		goto err;
900 	}
901 
902 	ret = bch2_fs_counters_init(c) ?:
903 	    bch2_fs_sb_errors_init(c) ?:
904 	    bch2_io_clock_init(&c->io_clock[READ]) ?:
905 	    bch2_io_clock_init(&c->io_clock[WRITE]) ?:
906 	    bch2_fs_journal_init(&c->journal) ?:
907 	    bch2_fs_btree_iter_init(c) ?:
908 	    bch2_fs_btree_cache_init(c) ?:
909 	    bch2_fs_btree_key_cache_init(&c->btree_key_cache) ?:
910 	    bch2_fs_btree_interior_update_init(c) ?:
911 	    bch2_fs_btree_gc_init(c) ?:
912 	    bch2_fs_buckets_waiting_for_journal_init(c) ?:
913 	    bch2_fs_btree_write_buffer_init(c) ?:
914 	    bch2_fs_subvolumes_init(c) ?:
915 	    bch2_fs_io_read_init(c) ?:
916 	    bch2_fs_io_write_init(c) ?:
917 	    bch2_fs_nocow_locking_init(c) ?:
918 	    bch2_fs_encryption_init(c) ?:
919 	    bch2_fs_compress_init(c) ?:
920 	    bch2_fs_ec_init(c) ?:
921 	    bch2_fs_vfs_init(c) ?:
922 	    bch2_fs_fsio_init(c) ?:
923 	    bch2_fs_fs_io_buffered_init(c) ?:
924 	    bch2_fs_fs_io_direct_init(c);
925 	if (ret)
926 		goto err;
927 
928 	for (i = 0; i < c->sb.nr_devices; i++) {
929 		if (!bch2_member_exists(c->disk_sb.sb, i))
930 			continue;
931 		ret = bch2_dev_alloc(c, i);
932 		if (ret)
933 			goto err;
934 	}
935 
936 	bch2_journal_entry_res_resize(&c->journal,
937 			&c->btree_root_journal_res,
938 			BTREE_ID_NR * (JSET_KEYS_U64s + BKEY_BTREE_PTR_U64s_MAX));
939 	bch2_journal_entry_res_resize(&c->journal,
940 			&c->clock_journal_res,
941 			(sizeof(struct jset_entry_clock) / sizeof(u64)) * 2);
942 
943 	mutex_lock(&bch_fs_list_lock);
944 	ret = bch2_fs_online(c);
945 	mutex_unlock(&bch_fs_list_lock);
946 
947 	if (ret)
948 		goto err;
949 out:
950 	return c;
951 err:
952 	bch2_fs_free(c);
953 	c = ERR_PTR(ret);
954 	goto out;
955 }
956 
957 noinline_for_stack
958 static void print_mount_opts(struct bch_fs *c)
959 {
960 	enum bch_opt_id i;
961 	struct printbuf p = PRINTBUF;
962 	bool first = true;
963 
964 	prt_str(&p, "starting version ");
965 	bch2_version_to_text(&p, c->sb.version);
966 
967 	if (c->opts.read_only) {
968 		prt_str(&p, " opts=");
969 		first = false;
970 		prt_printf(&p, "ro");
971 	}
972 
973 	for (i = 0; i < bch2_opts_nr; i++) {
974 		const struct bch_option *opt = &bch2_opt_table[i];
975 		u64 v = bch2_opt_get_by_id(&c->opts, i);
976 
977 		if (!(opt->flags & OPT_MOUNT))
978 			continue;
979 
980 		if (v == bch2_opt_get_by_id(&bch2_opts_default, i))
981 			continue;
982 
983 		prt_str(&p, first ? " opts=" : ",");
984 		first = false;
985 		bch2_opt_to_text(&p, c, c->disk_sb.sb, opt, v, OPT_SHOW_MOUNT_STYLE);
986 	}
987 
988 	bch_info(c, "%s", p.buf);
989 	printbuf_exit(&p);
990 }
991 
992 int bch2_fs_start(struct bch_fs *c)
993 {
994 	time64_t now = ktime_get_real_seconds();
995 	int ret;
996 
997 	print_mount_opts(c);
998 
999 	down_write(&c->state_lock);
1000 
1001 	BUG_ON(test_bit(BCH_FS_started, &c->flags));
1002 
1003 	mutex_lock(&c->sb_lock);
1004 
1005 	ret = bch2_sb_members_v2_init(c);
1006 	if (ret) {
1007 		mutex_unlock(&c->sb_lock);
1008 		goto err;
1009 	}
1010 
1011 	for_each_online_member(c, ca)
1012 		bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount = cpu_to_le64(now);
1013 
1014 	struct bch_sb_field_ext *ext =
1015 		bch2_sb_field_get_minsize(&c->disk_sb, ext, sizeof(*ext) / sizeof(u64));
1016 	mutex_unlock(&c->sb_lock);
1017 
1018 	if (!ext) {
1019 		bch_err(c, "insufficient space in superblock for sb_field_ext");
1020 		ret = -BCH_ERR_ENOSPC_sb;
1021 		goto err;
1022 	}
1023 
1024 	for_each_rw_member(c, ca)
1025 		bch2_dev_allocator_add(c, ca);
1026 	bch2_recalc_capacity(c);
1027 
1028 	c->recovery_task = current;
1029 	ret = BCH_SB_INITIALIZED(c->disk_sb.sb)
1030 		? bch2_fs_recovery(c)
1031 		: bch2_fs_initialize(c);
1032 	c->recovery_task = NULL;
1033 
1034 	if (ret)
1035 		goto err;
1036 
1037 	ret = bch2_opts_check_may_set(c);
1038 	if (ret)
1039 		goto err;
1040 
1041 	if (bch2_fs_init_fault("fs_start")) {
1042 		bch_err(c, "fs_start fault injected");
1043 		ret = -EINVAL;
1044 		goto err;
1045 	}
1046 
1047 	set_bit(BCH_FS_started, &c->flags);
1048 
1049 	if (c->opts.read_only) {
1050 		bch2_fs_read_only(c);
1051 	} else {
1052 		ret = !test_bit(BCH_FS_rw, &c->flags)
1053 			? bch2_fs_read_write(c)
1054 			: bch2_fs_read_write_late(c);
1055 		if (ret)
1056 			goto err;
1057 	}
1058 
1059 	ret = 0;
1060 err:
1061 	if (ret)
1062 		bch_err_msg(c, ret, "starting filesystem");
1063 	else
1064 		bch_verbose(c, "done starting filesystem");
1065 	up_write(&c->state_lock);
1066 	return ret;
1067 }
1068 
1069 static int bch2_dev_may_add(struct bch_sb *sb, struct bch_fs *c)
1070 {
1071 	struct bch_member m = bch2_sb_member_get(sb, sb->dev_idx);
1072 
1073 	if (le16_to_cpu(sb->block_size) != block_sectors(c))
1074 		return -BCH_ERR_mismatched_block_size;
1075 
1076 	if (le16_to_cpu(m.bucket_size) <
1077 	    BCH_SB_BTREE_NODE_SIZE(c->disk_sb.sb))
1078 		return -BCH_ERR_bucket_size_too_small;
1079 
1080 	return 0;
1081 }
1082 
1083 static int bch2_dev_in_fs(struct bch_sb_handle *fs,
1084 			  struct bch_sb_handle *sb,
1085 			  struct bch_opts *opts)
1086 {
1087 	if (fs == sb)
1088 		return 0;
1089 
1090 	if (!uuid_equal(&fs->sb->uuid, &sb->sb->uuid))
1091 		return -BCH_ERR_device_not_a_member_of_filesystem;
1092 
1093 	if (!bch2_member_exists(fs->sb, sb->sb->dev_idx))
1094 		return -BCH_ERR_device_has_been_removed;
1095 
1096 	if (fs->sb->block_size != sb->sb->block_size)
1097 		return -BCH_ERR_mismatched_block_size;
1098 
1099 	if (le16_to_cpu(fs->sb->version) < bcachefs_metadata_version_member_seq ||
1100 	    le16_to_cpu(sb->sb->version) < bcachefs_metadata_version_member_seq)
1101 		return 0;
1102 
1103 	if (fs->sb->seq == sb->sb->seq &&
1104 	    fs->sb->write_time != sb->sb->write_time) {
1105 		struct printbuf buf = PRINTBUF;
1106 
1107 		prt_str(&buf, "Split brain detected between ");
1108 		prt_bdevname(&buf, sb->bdev);
1109 		prt_str(&buf, " and ");
1110 		prt_bdevname(&buf, fs->bdev);
1111 		prt_char(&buf, ':');
1112 		prt_newline(&buf);
1113 		prt_printf(&buf, "seq=%llu but write_time different, got", le64_to_cpu(sb->sb->seq));
1114 		prt_newline(&buf);
1115 
1116 		prt_bdevname(&buf, fs->bdev);
1117 		prt_char(&buf, ' ');
1118 		bch2_prt_datetime(&buf, le64_to_cpu(fs->sb->write_time));
1119 		prt_newline(&buf);
1120 
1121 		prt_bdevname(&buf, sb->bdev);
1122 		prt_char(&buf, ' ');
1123 		bch2_prt_datetime(&buf, le64_to_cpu(sb->sb->write_time));
1124 		prt_newline(&buf);
1125 
1126 		if (!opts->no_splitbrain_check)
1127 			prt_printf(&buf, "Not using older sb");
1128 
1129 		pr_err("%s", buf.buf);
1130 		printbuf_exit(&buf);
1131 
1132 		if (!opts->no_splitbrain_check)
1133 			return -BCH_ERR_device_splitbrain;
1134 	}
1135 
1136 	struct bch_member m = bch2_sb_member_get(fs->sb, sb->sb->dev_idx);
1137 	u64 seq_from_fs		= le64_to_cpu(m.seq);
1138 	u64 seq_from_member	= le64_to_cpu(sb->sb->seq);
1139 
1140 	if (seq_from_fs && seq_from_fs < seq_from_member) {
1141 		struct printbuf buf = PRINTBUF;
1142 
1143 		prt_str(&buf, "Split brain detected between ");
1144 		prt_bdevname(&buf, sb->bdev);
1145 		prt_str(&buf, " and ");
1146 		prt_bdevname(&buf, fs->bdev);
1147 		prt_char(&buf, ':');
1148 		prt_newline(&buf);
1149 
1150 		prt_bdevname(&buf, fs->bdev);
1151 		prt_str(&buf, " believes seq of ");
1152 		prt_bdevname(&buf, sb->bdev);
1153 		prt_printf(&buf, " to be %llu, but ", seq_from_fs);
1154 		prt_bdevname(&buf, sb->bdev);
1155 		prt_printf(&buf, " has %llu\n", seq_from_member);
1156 
1157 		if (!opts->no_splitbrain_check) {
1158 			prt_str(&buf, "Not using ");
1159 			prt_bdevname(&buf, sb->bdev);
1160 		}
1161 
1162 		pr_err("%s", buf.buf);
1163 		printbuf_exit(&buf);
1164 
1165 		if (!opts->no_splitbrain_check)
1166 			return -BCH_ERR_device_splitbrain;
1167 	}
1168 
1169 	return 0;
1170 }
1171 
1172 /* Device startup/shutdown: */
1173 
1174 static void bch2_dev_release(struct kobject *kobj)
1175 {
1176 	struct bch_dev *ca = container_of(kobj, struct bch_dev, kobj);
1177 
1178 	kfree(ca);
1179 }
1180 
1181 static void bch2_dev_free(struct bch_dev *ca)
1182 {
1183 	cancel_work_sync(&ca->io_error_work);
1184 
1185 	bch2_dev_unlink(ca);
1186 
1187 	if (ca->kobj.state_in_sysfs)
1188 		kobject_del(&ca->kobj);
1189 
1190 	bch2_free_super(&ca->disk_sb);
1191 	bch2_dev_allocator_background_exit(ca);
1192 	bch2_dev_journal_exit(ca);
1193 
1194 	free_percpu(ca->io_done);
1195 	bch2_dev_buckets_free(ca);
1196 	kfree(ca->sb_read_scratch);
1197 
1198 	bch2_time_stats_quantiles_exit(&ca->io_latency[WRITE]);
1199 	bch2_time_stats_quantiles_exit(&ca->io_latency[READ]);
1200 
1201 	percpu_ref_exit(&ca->io_ref);
1202 #ifndef CONFIG_BCACHEFS_DEBUG
1203 	percpu_ref_exit(&ca->ref);
1204 #endif
1205 	kobject_put(&ca->kobj);
1206 }
1207 
1208 static void __bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca)
1209 {
1210 
1211 	lockdep_assert_held(&c->state_lock);
1212 
1213 	if (percpu_ref_is_zero(&ca->io_ref))
1214 		return;
1215 
1216 	__bch2_dev_read_only(c, ca);
1217 
1218 	reinit_completion(&ca->io_ref_completion);
1219 	percpu_ref_kill(&ca->io_ref);
1220 	wait_for_completion(&ca->io_ref_completion);
1221 
1222 	bch2_dev_unlink(ca);
1223 
1224 	bch2_free_super(&ca->disk_sb);
1225 	bch2_dev_journal_exit(ca);
1226 }
1227 
1228 #ifndef CONFIG_BCACHEFS_DEBUG
1229 static void bch2_dev_ref_complete(struct percpu_ref *ref)
1230 {
1231 	struct bch_dev *ca = container_of(ref, struct bch_dev, ref);
1232 
1233 	complete(&ca->ref_completion);
1234 }
1235 #endif
1236 
1237 static void bch2_dev_io_ref_complete(struct percpu_ref *ref)
1238 {
1239 	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref);
1240 
1241 	complete(&ca->io_ref_completion);
1242 }
1243 
1244 static void bch2_dev_unlink(struct bch_dev *ca)
1245 {
1246 	struct kobject *b;
1247 
1248 	/*
1249 	 * This is racy w.r.t. the underlying block device being hot-removed,
1250 	 * which removes it from sysfs.
1251 	 *
1252 	 * It'd be lovely if we had a way to handle this race, but the sysfs
1253 	 * code doesn't appear to provide a good method and block/holder.c is
1254 	 * susceptible as well:
1255 	 */
1256 	if (ca->kobj.state_in_sysfs &&
1257 	    ca->disk_sb.bdev &&
1258 	    (b = bdev_kobj(ca->disk_sb.bdev))->state_in_sysfs) {
1259 		sysfs_remove_link(b, "bcachefs");
1260 		sysfs_remove_link(&ca->kobj, "block");
1261 	}
1262 }
1263 
1264 static int bch2_dev_sysfs_online(struct bch_fs *c, struct bch_dev *ca)
1265 {
1266 	int ret;
1267 
1268 	if (!c->kobj.state_in_sysfs)
1269 		return 0;
1270 
1271 	if (!ca->kobj.state_in_sysfs) {
1272 		ret = kobject_add(&ca->kobj, &c->kobj,
1273 				  "dev-%u", ca->dev_idx);
1274 		if (ret)
1275 			return ret;
1276 	}
1277 
1278 	if (ca->disk_sb.bdev) {
1279 		struct kobject *block = bdev_kobj(ca->disk_sb.bdev);
1280 
1281 		ret = sysfs_create_link(block, &ca->kobj, "bcachefs");
1282 		if (ret)
1283 			return ret;
1284 
1285 		ret = sysfs_create_link(&ca->kobj, block, "block");
1286 		if (ret)
1287 			return ret;
1288 	}
1289 
1290 	return 0;
1291 }
1292 
1293 static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
1294 					struct bch_member *member)
1295 {
1296 	struct bch_dev *ca;
1297 	unsigned i;
1298 
1299 	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
1300 	if (!ca)
1301 		return NULL;
1302 
1303 	kobject_init(&ca->kobj, &bch2_dev_ktype);
1304 	init_completion(&ca->ref_completion);
1305 	init_completion(&ca->io_ref_completion);
1306 
1307 	INIT_WORK(&ca->io_error_work, bch2_io_error_work);
1308 
1309 	bch2_time_stats_quantiles_init(&ca->io_latency[READ]);
1310 	bch2_time_stats_quantiles_init(&ca->io_latency[WRITE]);
1311 
1312 	ca->mi = bch2_mi_to_cpu(member);
1313 
1314 	for (i = 0; i < ARRAY_SIZE(member->errors); i++)
1315 		atomic64_set(&ca->errors[i], le64_to_cpu(member->errors[i]));
1316 
1317 	ca->uuid = member->uuid;
1318 
1319 	ca->nr_btree_reserve = DIV_ROUND_UP(BTREE_NODE_RESERVE,
1320 			     ca->mi.bucket_size / btree_sectors(c));
1321 
1322 #ifndef CONFIG_BCACHEFS_DEBUG
1323 	if (percpu_ref_init(&ca->ref, bch2_dev_ref_complete, 0, GFP_KERNEL))
1324 		goto err;
1325 #else
1326 	atomic_long_set(&ca->ref, 1);
1327 #endif
1328 
1329 	bch2_dev_allocator_background_init(ca);
1330 
1331 	if (percpu_ref_init(&ca->io_ref, bch2_dev_io_ref_complete,
1332 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
1333 	    !(ca->sb_read_scratch = kmalloc(BCH_SB_READ_SCRATCH_BUF_SIZE, GFP_KERNEL)) ||
1334 	    bch2_dev_buckets_alloc(c, ca) ||
1335 	    !(ca->io_done	= alloc_percpu(*ca->io_done)))
1336 		goto err;
1337 
1338 	return ca;
1339 err:
1340 	bch2_dev_free(ca);
1341 	return NULL;
1342 }
1343 
1344 static void bch2_dev_attach(struct bch_fs *c, struct bch_dev *ca,
1345 			    unsigned dev_idx)
1346 {
1347 	ca->dev_idx = dev_idx;
1348 	__set_bit(ca->dev_idx, ca->self.d);
1349 	scnprintf(ca->name, sizeof(ca->name), "dev-%u", dev_idx);
1350 
1351 	ca->fs = c;
1352 	rcu_assign_pointer(c->devs[ca->dev_idx], ca);
1353 
1354 	if (bch2_dev_sysfs_online(c, ca))
1355 		pr_warn("error creating sysfs objects");
1356 }
1357 
1358 static int bch2_dev_alloc(struct bch_fs *c, unsigned dev_idx)
1359 {
1360 	struct bch_member member = bch2_sb_member_get(c->disk_sb.sb, dev_idx);
1361 	struct bch_dev *ca = NULL;
1362 
1363 	if (bch2_fs_init_fault("dev_alloc"))
1364 		goto err;
1365 
1366 	ca = __bch2_dev_alloc(c, &member);
1367 	if (!ca)
1368 		goto err;
1369 
1370 	ca->fs = c;
1371 
1372 	bch2_dev_attach(c, ca, dev_idx);
1373 	return 0;
1374 err:
1375 	return -BCH_ERR_ENOMEM_dev_alloc;
1376 }
1377 
1378 static int __bch2_dev_attach_bdev(struct bch_dev *ca, struct bch_sb_handle *sb)
1379 {
1380 	unsigned ret;
1381 
1382 	if (bch2_dev_is_online(ca)) {
1383 		bch_err(ca, "already have device online in slot %u",
1384 			sb->sb->dev_idx);
1385 		return -BCH_ERR_device_already_online;
1386 	}
1387 
1388 	if (get_capacity(sb->bdev->bd_disk) <
1389 	    ca->mi.bucket_size * ca->mi.nbuckets) {
1390 		bch_err(ca, "cannot online: device too small");
1391 		return -BCH_ERR_device_size_too_small;
1392 	}
1393 
1394 	BUG_ON(!percpu_ref_is_zero(&ca->io_ref));
1395 
1396 	ret = bch2_dev_journal_init(ca, sb->sb);
1397 	if (ret)
1398 		return ret;
1399 
1400 	/* Commit: */
1401 	ca->disk_sb = *sb;
1402 	memset(sb, 0, sizeof(*sb));
1403 
1404 	ca->dev = ca->disk_sb.bdev->bd_dev;
1405 
1406 	percpu_ref_reinit(&ca->io_ref);
1407 
1408 	return 0;
1409 }
1410 
1411 static int bch2_dev_attach_bdev(struct bch_fs *c, struct bch_sb_handle *sb)
1412 {
1413 	struct bch_dev *ca;
1414 	int ret;
1415 
1416 	lockdep_assert_held(&c->state_lock);
1417 
1418 	if (le64_to_cpu(sb->sb->seq) >
1419 	    le64_to_cpu(c->disk_sb.sb->seq))
1420 		bch2_sb_to_fs(c, sb->sb);
1421 
1422 	BUG_ON(!bch2_dev_exists(c, sb->sb->dev_idx));
1423 
1424 	ca = bch2_dev_locked(c, sb->sb->dev_idx);
1425 
1426 	ret = __bch2_dev_attach_bdev(ca, sb);
1427 	if (ret)
1428 		return ret;
1429 
1430 	bch2_dev_sysfs_online(c, ca);
1431 
1432 	struct printbuf name = PRINTBUF;
1433 	prt_bdevname(&name, ca->disk_sb.bdev);
1434 
1435 	if (c->sb.nr_devices == 1)
1436 		strscpy(c->name, name.buf, sizeof(c->name));
1437 	strscpy(ca->name, name.buf, sizeof(ca->name));
1438 
1439 	printbuf_exit(&name);
1440 
1441 	rebalance_wakeup(c);
1442 	return 0;
1443 }
1444 
1445 /* Device management: */
1446 
1447 /*
1448  * Note: this function is also used by the error paths - when a particular
1449  * device sees an error, we call it to determine whether we can just set the
1450  * device RO, or - if this function returns false - we'll set the whole
1451  * filesystem RO:
1452  *
1453  * XXX: maybe we should be more explicit about whether we're changing state
1454  * because we got an error or what have you?
1455  */
1456 bool bch2_dev_state_allowed(struct bch_fs *c, struct bch_dev *ca,
1457 			    enum bch_member_state new_state, int flags)
1458 {
1459 	struct bch_devs_mask new_online_devs;
1460 	int nr_rw = 0, required;
1461 
1462 	lockdep_assert_held(&c->state_lock);
1463 
1464 	switch (new_state) {
1465 	case BCH_MEMBER_STATE_rw:
1466 		return true;
1467 	case BCH_MEMBER_STATE_ro:
1468 		if (ca->mi.state != BCH_MEMBER_STATE_rw)
1469 			return true;
1470 
1471 		/* do we have enough devices to write to?  */
1472 		for_each_member_device(c, ca2)
1473 			if (ca2 != ca)
1474 				nr_rw += ca2->mi.state == BCH_MEMBER_STATE_rw;
1475 
1476 		required = max(!(flags & BCH_FORCE_IF_METADATA_DEGRADED)
1477 			       ? c->opts.metadata_replicas
1478 			       : metadata_replicas_required(c),
1479 			       !(flags & BCH_FORCE_IF_DATA_DEGRADED)
1480 			       ? c->opts.data_replicas
1481 			       : data_replicas_required(c));
1482 
1483 		return nr_rw >= required;
1484 	case BCH_MEMBER_STATE_failed:
1485 	case BCH_MEMBER_STATE_spare:
1486 		if (ca->mi.state != BCH_MEMBER_STATE_rw &&
1487 		    ca->mi.state != BCH_MEMBER_STATE_ro)
1488 			return true;
1489 
1490 		/* do we have enough devices to read from?  */
1491 		new_online_devs = bch2_online_devs(c);
1492 		__clear_bit(ca->dev_idx, new_online_devs.d);
1493 
1494 		return bch2_have_enough_devs(c, new_online_devs, flags, false);
1495 	default:
1496 		BUG();
1497 	}
1498 }
1499 
1500 static bool bch2_fs_may_start(struct bch_fs *c)
1501 {
1502 	struct bch_dev *ca;
1503 	unsigned i, flags = 0;
1504 
1505 	if (c->opts.very_degraded)
1506 		flags |= BCH_FORCE_IF_DEGRADED|BCH_FORCE_IF_LOST;
1507 
1508 	if (c->opts.degraded)
1509 		flags |= BCH_FORCE_IF_DEGRADED;
1510 
1511 	if (!c->opts.degraded &&
1512 	    !c->opts.very_degraded) {
1513 		mutex_lock(&c->sb_lock);
1514 
1515 		for (i = 0; i < c->disk_sb.sb->nr_devices; i++) {
1516 			if (!bch2_member_exists(c->disk_sb.sb, i))
1517 				continue;
1518 
1519 			ca = bch2_dev_locked(c, i);
1520 
1521 			if (!bch2_dev_is_online(ca) &&
1522 			    (ca->mi.state == BCH_MEMBER_STATE_rw ||
1523 			     ca->mi.state == BCH_MEMBER_STATE_ro)) {
1524 				mutex_unlock(&c->sb_lock);
1525 				return false;
1526 			}
1527 		}
1528 		mutex_unlock(&c->sb_lock);
1529 	}
1530 
1531 	return bch2_have_enough_devs(c, bch2_online_devs(c), flags, true);
1532 }
1533 
1534 static void __bch2_dev_read_only(struct bch_fs *c, struct bch_dev *ca)
1535 {
1536 	/*
1537 	 * The allocator thread itself allocates btree nodes, so stop it first:
1538 	 */
1539 	bch2_dev_allocator_remove(c, ca);
1540 	bch2_recalc_capacity(c);
1541 	bch2_dev_journal_stop(&c->journal, ca);
1542 }
1543 
1544 static void __bch2_dev_read_write(struct bch_fs *c, struct bch_dev *ca)
1545 {
1546 	lockdep_assert_held(&c->state_lock);
1547 
1548 	BUG_ON(ca->mi.state != BCH_MEMBER_STATE_rw);
1549 
1550 	bch2_dev_allocator_add(c, ca);
1551 	bch2_recalc_capacity(c);
1552 	bch2_dev_do_discards(ca);
1553 }
1554 
1555 int __bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1556 			 enum bch_member_state new_state, int flags)
1557 {
1558 	struct bch_member *m;
1559 	int ret = 0;
1560 
1561 	if (ca->mi.state == new_state)
1562 		return 0;
1563 
1564 	if (!bch2_dev_state_allowed(c, ca, new_state, flags))
1565 		return -BCH_ERR_device_state_not_allowed;
1566 
1567 	if (new_state != BCH_MEMBER_STATE_rw)
1568 		__bch2_dev_read_only(c, ca);
1569 
1570 	bch_notice(ca, "%s", bch2_member_states[new_state]);
1571 
1572 	mutex_lock(&c->sb_lock);
1573 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
1574 	SET_BCH_MEMBER_STATE(m, new_state);
1575 	bch2_write_super(c);
1576 	mutex_unlock(&c->sb_lock);
1577 
1578 	if (new_state == BCH_MEMBER_STATE_rw)
1579 		__bch2_dev_read_write(c, ca);
1580 
1581 	rebalance_wakeup(c);
1582 
1583 	return ret;
1584 }
1585 
1586 int bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1587 		       enum bch_member_state new_state, int flags)
1588 {
1589 	int ret;
1590 
1591 	down_write(&c->state_lock);
1592 	ret = __bch2_dev_set_state(c, ca, new_state, flags);
1593 	up_write(&c->state_lock);
1594 
1595 	return ret;
1596 }
1597 
1598 /* Device add/removal: */
1599 
1600 int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
1601 {
1602 	struct bch_member *m;
1603 	unsigned dev_idx = ca->dev_idx, data;
1604 	int ret;
1605 
1606 	down_write(&c->state_lock);
1607 
1608 	/*
1609 	 * We consume a reference to ca->ref, regardless of whether we succeed
1610 	 * or fail:
1611 	 */
1612 	bch2_dev_put(ca);
1613 
1614 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1615 		bch_err(ca, "Cannot remove without losing data");
1616 		ret = -BCH_ERR_device_state_not_allowed;
1617 		goto err;
1618 	}
1619 
1620 	__bch2_dev_read_only(c, ca);
1621 
1622 	ret = bch2_dev_data_drop(c, ca->dev_idx, flags);
1623 	bch_err_msg(ca, ret, "bch2_dev_data_drop()");
1624 	if (ret)
1625 		goto err;
1626 
1627 	ret = bch2_dev_remove_alloc(c, ca);
1628 	bch_err_msg(ca, ret, "bch2_dev_remove_alloc()");
1629 	if (ret)
1630 		goto err;
1631 
1632 	/*
1633 	 * We need to flush the entire journal to get rid of keys that reference
1634 	 * the device being removed before removing the superblock entry
1635 	 */
1636 	bch2_journal_flush_all_pins(&c->journal);
1637 
1638 	/*
1639 	 * this is really just needed for the bch2_replicas_gc_(start|end)
1640 	 * calls, and could be cleaned up:
1641 	 */
1642 	ret = bch2_journal_flush_device_pins(&c->journal, ca->dev_idx);
1643 	bch_err_msg(ca, ret, "bch2_journal_flush_device_pins()");
1644 	if (ret)
1645 		goto err;
1646 
1647 	ret = bch2_journal_flush(&c->journal);
1648 	bch_err_msg(ca, ret, "bch2_journal_flush()");
1649 	if (ret)
1650 		goto err;
1651 
1652 	ret = bch2_replicas_gc2(c);
1653 	bch_err_msg(ca, ret, "bch2_replicas_gc2()");
1654 	if (ret)
1655 		goto err;
1656 
1657 	data = bch2_dev_has_data(c, ca);
1658 	if (data) {
1659 		struct printbuf data_has = PRINTBUF;
1660 
1661 		prt_bitflags(&data_has, __bch2_data_types, data);
1662 		bch_err(ca, "Remove failed, still has data (%s)", data_has.buf);
1663 		printbuf_exit(&data_has);
1664 		ret = -EBUSY;
1665 		goto err;
1666 	}
1667 
1668 	__bch2_dev_offline(c, ca);
1669 
1670 	mutex_lock(&c->sb_lock);
1671 	rcu_assign_pointer(c->devs[ca->dev_idx], NULL);
1672 	mutex_unlock(&c->sb_lock);
1673 
1674 #ifndef CONFIG_BCACHEFS_DEBUG
1675 	percpu_ref_kill(&ca->ref);
1676 #else
1677 	ca->dying = true;
1678 	bch2_dev_put(ca);
1679 #endif
1680 	wait_for_completion(&ca->ref_completion);
1681 
1682 	bch2_dev_free(ca);
1683 
1684 	/*
1685 	 * Free this device's slot in the bch_member array - all pointers to
1686 	 * this device must be gone:
1687 	 */
1688 	mutex_lock(&c->sb_lock);
1689 	m = bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx);
1690 	memset(&m->uuid, 0, sizeof(m->uuid));
1691 
1692 	bch2_write_super(c);
1693 
1694 	mutex_unlock(&c->sb_lock);
1695 	up_write(&c->state_lock);
1696 	return 0;
1697 err:
1698 	if (ca->mi.state == BCH_MEMBER_STATE_rw &&
1699 	    !percpu_ref_is_zero(&ca->io_ref))
1700 		__bch2_dev_read_write(c, ca);
1701 	up_write(&c->state_lock);
1702 	return ret;
1703 }
1704 
1705 /* Add new device to running filesystem: */
1706 int bch2_dev_add(struct bch_fs *c, const char *path)
1707 {
1708 	struct bch_opts opts = bch2_opts_empty();
1709 	struct bch_sb_handle sb;
1710 	struct bch_dev *ca = NULL;
1711 	struct printbuf errbuf = PRINTBUF;
1712 	struct printbuf label = PRINTBUF;
1713 	int ret;
1714 
1715 	ret = bch2_read_super(path, &opts, &sb);
1716 	bch_err_msg(c, ret, "reading super");
1717 	if (ret)
1718 		goto err;
1719 
1720 	struct bch_member dev_mi = bch2_sb_member_get(sb.sb, sb.sb->dev_idx);
1721 
1722 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1723 		bch2_disk_path_to_text_sb(&label, sb.sb, BCH_MEMBER_GROUP(&dev_mi) - 1);
1724 		if (label.allocation_failure) {
1725 			ret = -ENOMEM;
1726 			goto err;
1727 		}
1728 	}
1729 
1730 	ret = bch2_dev_may_add(sb.sb, c);
1731 	if (ret)
1732 		goto err;
1733 
1734 	ca = __bch2_dev_alloc(c, &dev_mi);
1735 	if (!ca) {
1736 		ret = -ENOMEM;
1737 		goto err;
1738 	}
1739 
1740 	ret = __bch2_dev_attach_bdev(ca, &sb);
1741 	if (ret)
1742 		goto err;
1743 
1744 	down_write(&c->state_lock);
1745 	mutex_lock(&c->sb_lock);
1746 
1747 	ret = bch2_sb_from_fs(c, ca);
1748 	bch_err_msg(c, ret, "setting up new superblock");
1749 	if (ret)
1750 		goto err_unlock;
1751 
1752 	if (dynamic_fault("bcachefs:add:no_slot"))
1753 		goto err_unlock;
1754 
1755 	ret = bch2_sb_member_alloc(c);
1756 	if (ret < 0) {
1757 		bch_err_msg(c, ret, "setting up new superblock");
1758 		goto err_unlock;
1759 	}
1760 	unsigned dev_idx = ret;
1761 
1762 	/* success: */
1763 
1764 	dev_mi.last_mount = cpu_to_le64(ktime_get_real_seconds());
1765 	*bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx) = dev_mi;
1766 
1767 	ca->disk_sb.sb->dev_idx	= dev_idx;
1768 	bch2_dev_attach(c, ca, dev_idx);
1769 
1770 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1771 		ret = __bch2_dev_group_set(c, ca, label.buf);
1772 		bch_err_msg(c, ret, "creating new label");
1773 		if (ret)
1774 			goto err_unlock;
1775 	}
1776 
1777 	bch2_write_super(c);
1778 	mutex_unlock(&c->sb_lock);
1779 
1780 	ret = bch2_dev_usage_init(ca, false);
1781 	if (ret)
1782 		goto err_late;
1783 
1784 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1785 	bch_err_msg(ca, ret, "marking new superblock");
1786 	if (ret)
1787 		goto err_late;
1788 
1789 	ret = bch2_fs_freespace_init(c);
1790 	bch_err_msg(ca, ret, "initializing free space");
1791 	if (ret)
1792 		goto err_late;
1793 
1794 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1795 		__bch2_dev_read_write(c, ca);
1796 
1797 	ret = bch2_dev_journal_alloc(ca, false);
1798 	bch_err_msg(c, ret, "allocating journal");
1799 	if (ret)
1800 		goto err_late;
1801 
1802 	up_write(&c->state_lock);
1803 	return 0;
1804 
1805 err_unlock:
1806 	mutex_unlock(&c->sb_lock);
1807 	up_write(&c->state_lock);
1808 err:
1809 	if (ca)
1810 		bch2_dev_free(ca);
1811 	bch2_free_super(&sb);
1812 	printbuf_exit(&label);
1813 	printbuf_exit(&errbuf);
1814 	bch_err_fn(c, ret);
1815 	return ret;
1816 err_late:
1817 	up_write(&c->state_lock);
1818 	ca = NULL;
1819 	goto err;
1820 }
1821 
1822 /* Hot add existing device to running filesystem: */
1823 int bch2_dev_online(struct bch_fs *c, const char *path)
1824 {
1825 	struct bch_opts opts = bch2_opts_empty();
1826 	struct bch_sb_handle sb = { NULL };
1827 	struct bch_dev *ca;
1828 	unsigned dev_idx;
1829 	int ret;
1830 
1831 	down_write(&c->state_lock);
1832 
1833 	ret = bch2_read_super(path, &opts, &sb);
1834 	if (ret) {
1835 		up_write(&c->state_lock);
1836 		return ret;
1837 	}
1838 
1839 	dev_idx = sb.sb->dev_idx;
1840 
1841 	ret = bch2_dev_in_fs(&c->disk_sb, &sb, &c->opts);
1842 	bch_err_msg(c, ret, "bringing %s online", path);
1843 	if (ret)
1844 		goto err;
1845 
1846 	ret = bch2_dev_attach_bdev(c, &sb);
1847 	if (ret)
1848 		goto err;
1849 
1850 	ca = bch2_dev_locked(c, dev_idx);
1851 
1852 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1853 	bch_err_msg(c, ret, "bringing %s online: error from bch2_trans_mark_dev_sb", path);
1854 	if (ret)
1855 		goto err;
1856 
1857 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1858 		__bch2_dev_read_write(c, ca);
1859 
1860 	if (!ca->mi.freespace_initialized) {
1861 		ret = bch2_dev_freespace_init(c, ca, 0, ca->mi.nbuckets);
1862 		bch_err_msg(ca, ret, "initializing free space");
1863 		if (ret)
1864 			goto err;
1865 	}
1866 
1867 	if (!ca->journal.nr) {
1868 		ret = bch2_dev_journal_alloc(ca, false);
1869 		bch_err_msg(ca, ret, "allocating journal");
1870 		if (ret)
1871 			goto err;
1872 	}
1873 
1874 	mutex_lock(&c->sb_lock);
1875 	bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount =
1876 		cpu_to_le64(ktime_get_real_seconds());
1877 	bch2_write_super(c);
1878 	mutex_unlock(&c->sb_lock);
1879 
1880 	up_write(&c->state_lock);
1881 	return 0;
1882 err:
1883 	up_write(&c->state_lock);
1884 	bch2_free_super(&sb);
1885 	return ret;
1886 }
1887 
1888 int bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca, int flags)
1889 {
1890 	down_write(&c->state_lock);
1891 
1892 	if (!bch2_dev_is_online(ca)) {
1893 		bch_err(ca, "Already offline");
1894 		up_write(&c->state_lock);
1895 		return 0;
1896 	}
1897 
1898 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1899 		bch_err(ca, "Cannot offline required disk");
1900 		up_write(&c->state_lock);
1901 		return -BCH_ERR_device_state_not_allowed;
1902 	}
1903 
1904 	__bch2_dev_offline(c, ca);
1905 
1906 	up_write(&c->state_lock);
1907 	return 0;
1908 }
1909 
1910 int bch2_dev_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
1911 {
1912 	struct bch_member *m;
1913 	u64 old_nbuckets;
1914 	int ret = 0;
1915 
1916 	down_write(&c->state_lock);
1917 	old_nbuckets = ca->mi.nbuckets;
1918 
1919 	if (nbuckets < ca->mi.nbuckets) {
1920 		bch_err(ca, "Cannot shrink yet");
1921 		ret = -EINVAL;
1922 		goto err;
1923 	}
1924 
1925 	if (nbuckets > BCH_MEMBER_NBUCKETS_MAX) {
1926 		bch_err(ca, "New device size too big (%llu greater than max %u)",
1927 			nbuckets, BCH_MEMBER_NBUCKETS_MAX);
1928 		ret = -BCH_ERR_device_size_too_big;
1929 		goto err;
1930 	}
1931 
1932 	if (bch2_dev_is_online(ca) &&
1933 	    get_capacity(ca->disk_sb.bdev->bd_disk) <
1934 	    ca->mi.bucket_size * nbuckets) {
1935 		bch_err(ca, "New size larger than device");
1936 		ret = -BCH_ERR_device_size_too_small;
1937 		goto err;
1938 	}
1939 
1940 	ret = bch2_dev_buckets_resize(c, ca, nbuckets);
1941 	bch_err_msg(ca, ret, "resizing buckets");
1942 	if (ret)
1943 		goto err;
1944 
1945 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1946 	if (ret)
1947 		goto err;
1948 
1949 	mutex_lock(&c->sb_lock);
1950 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
1951 	m->nbuckets = cpu_to_le64(nbuckets);
1952 
1953 	bch2_write_super(c);
1954 	mutex_unlock(&c->sb_lock);
1955 
1956 	if (ca->mi.freespace_initialized) {
1957 		struct disk_accounting_pos acc = {
1958 			.type = BCH_DISK_ACCOUNTING_dev_data_type,
1959 			.dev_data_type.dev = ca->dev_idx,
1960 			.dev_data_type.data_type = BCH_DATA_free,
1961 		};
1962 		u64 v[3] = { nbuckets - old_nbuckets, 0, 0 };
1963 
1964 		ret   = bch2_trans_commit_do(ca->fs, NULL, NULL, 0,
1965 				bch2_disk_accounting_mod(trans, &acc, v, ARRAY_SIZE(v), false)) ?:
1966 			bch2_dev_freespace_init(c, ca, old_nbuckets, nbuckets);
1967 		if (ret)
1968 			goto err;
1969 	}
1970 
1971 	bch2_recalc_capacity(c);
1972 err:
1973 	up_write(&c->state_lock);
1974 	return ret;
1975 }
1976 
1977 /* return with ref on ca->ref: */
1978 struct bch_dev *bch2_dev_lookup(struct bch_fs *c, const char *name)
1979 {
1980 	if (!strncmp(name, "/dev/", strlen("/dev/")))
1981 		name += strlen("/dev/");
1982 
1983 	for_each_member_device(c, ca)
1984 		if (!strcmp(name, ca->name))
1985 			return ca;
1986 	return ERR_PTR(-BCH_ERR_ENOENT_dev_not_found);
1987 }
1988 
1989 /* Filesystem open: */
1990 
1991 static inline int sb_cmp(struct bch_sb *l, struct bch_sb *r)
1992 {
1993 	return  cmp_int(le64_to_cpu(l->seq), le64_to_cpu(r->seq)) ?:
1994 		cmp_int(le64_to_cpu(l->write_time), le64_to_cpu(r->write_time));
1995 }
1996 
1997 struct bch_fs *bch2_fs_open(char * const *devices, unsigned nr_devices,
1998 			    struct bch_opts opts)
1999 {
2000 	DARRAY(struct bch_sb_handle) sbs = { 0 };
2001 	struct bch_fs *c = NULL;
2002 	struct bch_sb_handle *best = NULL;
2003 	struct printbuf errbuf = PRINTBUF;
2004 	int ret = 0;
2005 
2006 	if (!try_module_get(THIS_MODULE))
2007 		return ERR_PTR(-ENODEV);
2008 
2009 	if (!nr_devices) {
2010 		ret = -EINVAL;
2011 		goto err;
2012 	}
2013 
2014 	ret = darray_make_room(&sbs, nr_devices);
2015 	if (ret)
2016 		goto err;
2017 
2018 	for (unsigned i = 0; i < nr_devices; i++) {
2019 		struct bch_sb_handle sb = { NULL };
2020 
2021 		ret = bch2_read_super(devices[i], &opts, &sb);
2022 		if (ret)
2023 			goto err;
2024 
2025 		BUG_ON(darray_push(&sbs, sb));
2026 	}
2027 
2028 	if (opts.nochanges && !opts.read_only) {
2029 		ret = -BCH_ERR_erofs_nochanges;
2030 		goto err_print;
2031 	}
2032 
2033 	darray_for_each(sbs, sb)
2034 		if (!best || sb_cmp(sb->sb, best->sb) > 0)
2035 			best = sb;
2036 
2037 	darray_for_each_reverse(sbs, sb) {
2038 		ret = bch2_dev_in_fs(best, sb, &opts);
2039 
2040 		if (ret == -BCH_ERR_device_has_been_removed ||
2041 		    ret == -BCH_ERR_device_splitbrain) {
2042 			bch2_free_super(sb);
2043 			darray_remove_item(&sbs, sb);
2044 			best -= best > sb;
2045 			ret = 0;
2046 			continue;
2047 		}
2048 
2049 		if (ret)
2050 			goto err_print;
2051 	}
2052 
2053 	c = bch2_fs_alloc(best->sb, opts);
2054 	ret = PTR_ERR_OR_ZERO(c);
2055 	if (ret)
2056 		goto err;
2057 
2058 	down_write(&c->state_lock);
2059 	darray_for_each(sbs, sb) {
2060 		ret = bch2_dev_attach_bdev(c, sb);
2061 		if (ret) {
2062 			up_write(&c->state_lock);
2063 			goto err;
2064 		}
2065 	}
2066 	up_write(&c->state_lock);
2067 
2068 	if (!bch2_fs_may_start(c)) {
2069 		ret = -BCH_ERR_insufficient_devices_to_start;
2070 		goto err_print;
2071 	}
2072 
2073 	if (!c->opts.nostart) {
2074 		ret = bch2_fs_start(c);
2075 		if (ret)
2076 			goto err;
2077 	}
2078 out:
2079 	darray_for_each(sbs, sb)
2080 		bch2_free_super(sb);
2081 	darray_exit(&sbs);
2082 	printbuf_exit(&errbuf);
2083 	module_put(THIS_MODULE);
2084 	return c;
2085 err_print:
2086 	pr_err("bch_fs_open err opening %s: %s",
2087 	       devices[0], bch2_err_str(ret));
2088 err:
2089 	if (!IS_ERR_OR_NULL(c))
2090 		bch2_fs_stop(c);
2091 	c = ERR_PTR(ret);
2092 	goto out;
2093 }
2094 
2095 /* Global interfaces/init */
2096 
2097 static void bcachefs_exit(void)
2098 {
2099 	bch2_debug_exit();
2100 	bch2_vfs_exit();
2101 	bch2_chardev_exit();
2102 	bch2_btree_key_cache_exit();
2103 	if (bcachefs_kset)
2104 		kset_unregister(bcachefs_kset);
2105 }
2106 
2107 static int __init bcachefs_init(void)
2108 {
2109 	bch2_bkey_pack_test();
2110 
2111 	if (!(bcachefs_kset = kset_create_and_add("bcachefs", NULL, fs_kobj)) ||
2112 	    bch2_btree_key_cache_init() ||
2113 	    bch2_chardev_init() ||
2114 	    bch2_vfs_init() ||
2115 	    bch2_debug_init())
2116 		goto err;
2117 
2118 	return 0;
2119 err:
2120 	bcachefs_exit();
2121 	return -ENOMEM;
2122 }
2123 
2124 #define BCH_DEBUG_PARAM(name, description)			\
2125 	bool bch2_##name;					\
2126 	module_param_named(name, bch2_##name, bool, 0644);	\
2127 	MODULE_PARM_DESC(name, description);
2128 BCH_DEBUG_PARAMS()
2129 #undef BCH_DEBUG_PARAM
2130 
2131 __maybe_unused
2132 static unsigned bch2_metadata_version = bcachefs_metadata_version_current;
2133 module_param_named(version, bch2_metadata_version, uint, 0400);
2134 
2135 module_exit(bcachefs_exit);
2136 module_init(bcachefs_init);
2137