xref: /linux/fs/bcachefs/super.c (revision f694f30e81c4ade358eb8c75273bac1a48f0cb8f)
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 
74 MODULE_LICENSE("GPL");
75 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
76 MODULE_DESCRIPTION("bcachefs filesystem");
77 
78 const char * const bch2_fs_flag_strs[] = {
79 #define x(n)		#n,
80 	BCH_FS_FLAGS()
81 #undef x
82 	NULL
83 };
84 
85 void bch2_print_str(struct bch_fs *c, const char *str)
86 {
87 #ifdef __KERNEL__
88 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
89 
90 	if (unlikely(stdio)) {
91 		bch2_stdio_redirect_printf(stdio, true, "%s", str);
92 		return;
93 	}
94 #endif
95 	bch2_print_string_as_lines(KERN_ERR, str);
96 }
97 
98 __printf(2, 0)
99 static void bch2_print_maybe_redirect(struct stdio_redirect *stdio, const char *fmt, va_list args)
100 {
101 #ifdef __KERNEL__
102 	if (unlikely(stdio)) {
103 		if (fmt[0] == KERN_SOH[0])
104 			fmt += 2;
105 
106 		bch2_stdio_redirect_vprintf(stdio, true, fmt, args);
107 		return;
108 	}
109 #endif
110 	vprintk(fmt, args);
111 }
112 
113 void bch2_print_opts(struct bch_opts *opts, const char *fmt, ...)
114 {
115 	struct stdio_redirect *stdio = (void *)(unsigned long)opts->stdio;
116 
117 	va_list args;
118 	va_start(args, fmt);
119 	bch2_print_maybe_redirect(stdio, fmt, args);
120 	va_end(args);
121 }
122 
123 void __bch2_print(struct bch_fs *c, const char *fmt, ...)
124 {
125 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
126 
127 	va_list args;
128 	va_start(args, fmt);
129 	bch2_print_maybe_redirect(stdio, fmt, args);
130 	va_end(args);
131 }
132 
133 #define KTYPE(type)							\
134 static const struct attribute_group type ## _group = {			\
135 	.attrs = type ## _files						\
136 };									\
137 									\
138 static const struct attribute_group *type ## _groups[] = {		\
139 	&type ## _group,						\
140 	NULL								\
141 };									\
142 									\
143 static const struct kobj_type type ## _ktype = {			\
144 	.release	= type ## _release,				\
145 	.sysfs_ops	= &type ## _sysfs_ops,				\
146 	.default_groups = type ## _groups				\
147 }
148 
149 static void bch2_fs_release(struct kobject *);
150 static void bch2_dev_release(struct kobject *);
151 static void bch2_fs_counters_release(struct kobject *k)
152 {
153 }
154 
155 static void bch2_fs_internal_release(struct kobject *k)
156 {
157 }
158 
159 static void bch2_fs_opts_dir_release(struct kobject *k)
160 {
161 }
162 
163 static void bch2_fs_time_stats_release(struct kobject *k)
164 {
165 }
166 
167 KTYPE(bch2_fs);
168 KTYPE(bch2_fs_counters);
169 KTYPE(bch2_fs_internal);
170 KTYPE(bch2_fs_opts_dir);
171 KTYPE(bch2_fs_time_stats);
172 KTYPE(bch2_dev);
173 
174 static struct kset *bcachefs_kset;
175 static LIST_HEAD(bch_fs_list);
176 static DEFINE_MUTEX(bch_fs_list_lock);
177 
178 DECLARE_WAIT_QUEUE_HEAD(bch2_read_only_wait);
179 
180 static void bch2_dev_unlink(struct bch_dev *);
181 static void bch2_dev_free(struct bch_dev *);
182 static int bch2_dev_alloc(struct bch_fs *, unsigned);
183 static int bch2_dev_sysfs_online(struct bch_fs *, struct bch_dev *);
184 static void bch2_dev_io_ref_stop(struct bch_dev *, int);
185 static void __bch2_dev_read_only(struct bch_fs *, struct bch_dev *);
186 
187 struct bch_fs *bch2_dev_to_fs(dev_t dev)
188 {
189 	struct bch_fs *c;
190 
191 	mutex_lock(&bch_fs_list_lock);
192 	rcu_read_lock();
193 
194 	list_for_each_entry(c, &bch_fs_list, list)
195 		for_each_member_device_rcu(c, ca, NULL)
196 			if (ca->disk_sb.bdev && ca->disk_sb.bdev->bd_dev == dev) {
197 				closure_get(&c->cl);
198 				goto found;
199 			}
200 	c = NULL;
201 found:
202 	rcu_read_unlock();
203 	mutex_unlock(&bch_fs_list_lock);
204 
205 	return c;
206 }
207 
208 static struct bch_fs *__bch2_uuid_to_fs(__uuid_t uuid)
209 {
210 	struct bch_fs *c;
211 
212 	lockdep_assert_held(&bch_fs_list_lock);
213 
214 	list_for_each_entry(c, &bch_fs_list, list)
215 		if (!memcmp(&c->disk_sb.sb->uuid, &uuid, sizeof(uuid)))
216 			return c;
217 
218 	return NULL;
219 }
220 
221 struct bch_fs *bch2_uuid_to_fs(__uuid_t uuid)
222 {
223 	struct bch_fs *c;
224 
225 	mutex_lock(&bch_fs_list_lock);
226 	c = __bch2_uuid_to_fs(uuid);
227 	if (c)
228 		closure_get(&c->cl);
229 	mutex_unlock(&bch_fs_list_lock);
230 
231 	return c;
232 }
233 
234 /* Filesystem RO/RW: */
235 
236 /*
237  * For startup/shutdown of RW stuff, the dependencies are:
238  *
239  * - foreground writes depend on copygc and rebalance (to free up space)
240  *
241  * - copygc and rebalance depend on mark and sweep gc (they actually probably
242  *   don't because they either reserve ahead of time or don't block if
243  *   allocations fail, but allocations can require mark and sweep gc to run
244  *   because of generation number wraparound)
245  *
246  * - all of the above depends on the allocator threads
247  *
248  * - allocator depends on the journal (when it rewrites prios and gens)
249  */
250 
251 static void __bch2_fs_read_only(struct bch_fs *c)
252 {
253 	unsigned clean_passes = 0;
254 	u64 seq = 0;
255 
256 	bch2_fs_ec_stop(c);
257 	bch2_open_buckets_stop(c, NULL, true);
258 	bch2_rebalance_stop(c);
259 	bch2_copygc_stop(c);
260 	bch2_fs_ec_flush(c);
261 
262 	bch_verbose(c, "flushing journal and stopping allocators, journal seq %llu",
263 		    journal_cur_seq(&c->journal));
264 
265 	do {
266 		clean_passes++;
267 
268 		if (bch2_btree_interior_updates_flush(c) ||
269 		    bch2_btree_write_buffer_flush_going_ro(c) ||
270 		    bch2_journal_flush_all_pins(&c->journal) ||
271 		    bch2_btree_flush_all_writes(c) ||
272 		    seq != atomic64_read(&c->journal.seq)) {
273 			seq = atomic64_read(&c->journal.seq);
274 			clean_passes = 0;
275 		}
276 	} while (clean_passes < 2);
277 
278 	bch_verbose(c, "flushing journal and stopping allocators complete, journal seq %llu",
279 		    journal_cur_seq(&c->journal));
280 
281 	if (test_bit(JOURNAL_replay_done, &c->journal.flags) &&
282 	    !test_bit(BCH_FS_emergency_ro, &c->flags))
283 		set_bit(BCH_FS_clean_shutdown, &c->flags);
284 
285 	bch2_fs_journal_stop(&c->journal);
286 
287 	bch_info(c, "%sclean shutdown complete, journal seq %llu",
288 		 test_bit(BCH_FS_clean_shutdown, &c->flags) ? "" : "un",
289 		 c->journal.seq_ondisk);
290 
291 	/*
292 	 * After stopping journal:
293 	 */
294 	for_each_member_device(c, ca) {
295 		bch2_dev_io_ref_stop(ca, WRITE);
296 		bch2_dev_allocator_remove(c, ca);
297 	}
298 }
299 
300 #ifndef BCH_WRITE_REF_DEBUG
301 static void bch2_writes_disabled(struct percpu_ref *writes)
302 {
303 	struct bch_fs *c = container_of(writes, struct bch_fs, writes);
304 
305 	set_bit(BCH_FS_write_disable_complete, &c->flags);
306 	wake_up(&bch2_read_only_wait);
307 }
308 #endif
309 
310 void bch2_fs_read_only(struct bch_fs *c)
311 {
312 	if (!test_bit(BCH_FS_rw, &c->flags)) {
313 		bch2_journal_reclaim_stop(&c->journal);
314 		return;
315 	}
316 
317 	BUG_ON(test_bit(BCH_FS_write_disable_complete, &c->flags));
318 
319 	bch_verbose(c, "going read-only");
320 
321 	/*
322 	 * Block new foreground-end write operations from starting - any new
323 	 * writes will return -EROFS:
324 	 */
325 	set_bit(BCH_FS_going_ro, &c->flags);
326 #ifndef BCH_WRITE_REF_DEBUG
327 	percpu_ref_kill(&c->writes);
328 #else
329 	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++)
330 		bch2_write_ref_put(c, i);
331 #endif
332 
333 	/*
334 	 * If we're not doing an emergency shutdown, we want to wait on
335 	 * outstanding writes to complete so they don't see spurious errors due
336 	 * to shutting down the allocator:
337 	 *
338 	 * If we are doing an emergency shutdown outstanding writes may
339 	 * hang until we shutdown the allocator so we don't want to wait
340 	 * on outstanding writes before shutting everything down - but
341 	 * we do need to wait on them before returning and signalling
342 	 * that going RO is complete:
343 	 */
344 	wait_event(bch2_read_only_wait,
345 		   test_bit(BCH_FS_write_disable_complete, &c->flags) ||
346 		   test_bit(BCH_FS_emergency_ro, &c->flags));
347 
348 	bool writes_disabled = test_bit(BCH_FS_write_disable_complete, &c->flags);
349 	if (writes_disabled)
350 		bch_verbose(c, "finished waiting for writes to stop");
351 
352 	__bch2_fs_read_only(c);
353 
354 	wait_event(bch2_read_only_wait,
355 		   test_bit(BCH_FS_write_disable_complete, &c->flags));
356 
357 	if (!writes_disabled)
358 		bch_verbose(c, "finished waiting for writes to stop");
359 
360 	clear_bit(BCH_FS_write_disable_complete, &c->flags);
361 	clear_bit(BCH_FS_going_ro, &c->flags);
362 	clear_bit(BCH_FS_rw, &c->flags);
363 
364 	if (!bch2_journal_error(&c->journal) &&
365 	    !test_bit(BCH_FS_error, &c->flags) &&
366 	    !test_bit(BCH_FS_emergency_ro, &c->flags) &&
367 	    test_bit(BCH_FS_started, &c->flags) &&
368 	    test_bit(BCH_FS_clean_shutdown, &c->flags) &&
369 	    c->recovery_pass_done >= BCH_RECOVERY_PASS_journal_replay) {
370 		BUG_ON(c->journal.last_empty_seq != journal_cur_seq(&c->journal));
371 		BUG_ON(atomic_long_read(&c->btree_cache.nr_dirty));
372 		BUG_ON(atomic_long_read(&c->btree_key_cache.nr_dirty));
373 		BUG_ON(c->btree_write_buffer.inc.keys.nr);
374 		BUG_ON(c->btree_write_buffer.flushing.keys.nr);
375 		bch2_verify_accounting_clean(c);
376 
377 		bch_verbose(c, "marking filesystem clean");
378 		bch2_fs_mark_clean(c);
379 	} else {
380 		bch_verbose(c, "done going read-only, filesystem not clean");
381 	}
382 }
383 
384 static void bch2_fs_read_only_work(struct work_struct *work)
385 {
386 	struct bch_fs *c =
387 		container_of(work, struct bch_fs, read_only_work);
388 
389 	down_write(&c->state_lock);
390 	bch2_fs_read_only(c);
391 	up_write(&c->state_lock);
392 }
393 
394 static void bch2_fs_read_only_async(struct bch_fs *c)
395 {
396 	queue_work(system_long_wq, &c->read_only_work);
397 }
398 
399 bool bch2_fs_emergency_read_only(struct bch_fs *c)
400 {
401 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
402 
403 	bch2_journal_halt(&c->journal);
404 	bch2_fs_read_only_async(c);
405 
406 	wake_up(&bch2_read_only_wait);
407 	return ret;
408 }
409 
410 bool bch2_fs_emergency_read_only_locked(struct bch_fs *c)
411 {
412 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
413 
414 	bch2_journal_halt_locked(&c->journal);
415 	bch2_fs_read_only_async(c);
416 
417 	wake_up(&bch2_read_only_wait);
418 	return ret;
419 }
420 
421 static int bch2_fs_read_write_late(struct bch_fs *c)
422 {
423 	int ret;
424 
425 	/*
426 	 * Data move operations can't run until after check_snapshots has
427 	 * completed, and bch2_snapshot_is_ancestor() is available.
428 	 *
429 	 * Ideally we'd start copygc/rebalance earlier instead of waiting for
430 	 * all of recovery/fsck to complete:
431 	 */
432 	ret = bch2_copygc_start(c);
433 	if (ret) {
434 		bch_err(c, "error starting copygc thread");
435 		return ret;
436 	}
437 
438 	ret = bch2_rebalance_start(c);
439 	if (ret) {
440 		bch_err(c, "error starting rebalance thread");
441 		return ret;
442 	}
443 
444 	return 0;
445 }
446 
447 static int __bch2_fs_read_write(struct bch_fs *c, bool early)
448 {
449 	int ret;
450 
451 	BUG_ON(!test_bit(BCH_FS_may_go_rw, &c->flags));
452 
453 	if (test_bit(BCH_FS_initial_gc_unfixed, &c->flags)) {
454 		bch_err(c, "cannot go rw, unfixed btree errors");
455 		return -BCH_ERR_erofs_unfixed_errors;
456 	}
457 
458 	if (test_bit(BCH_FS_rw, &c->flags))
459 		return 0;
460 
461 	bch_info(c, "going read-write");
462 
463 	ret = bch2_sb_members_v2_init(c);
464 	if (ret)
465 		goto err;
466 
467 	clear_bit(BCH_FS_clean_shutdown, &c->flags);
468 
469 	/*
470 	 * First journal write must be a flush write: after a clean shutdown we
471 	 * don't read the journal, so the first journal write may end up
472 	 * overwriting whatever was there previously, and there must always be
473 	 * at least one non-flush write in the journal or recovery will fail:
474 	 */
475 	set_bit(JOURNAL_need_flush_write, &c->journal.flags);
476 	set_bit(JOURNAL_running, &c->journal.flags);
477 
478 	__for_each_online_member(c, ca, BIT(BCH_MEMBER_STATE_rw), READ) {
479 		bch2_dev_allocator_add(c, ca);
480 		percpu_ref_reinit(&ca->io_ref[WRITE]);
481 	}
482 	bch2_recalc_capacity(c);
483 
484 	ret = bch2_fs_mark_dirty(c);
485 	if (ret)
486 		goto err;
487 
488 	spin_lock(&c->journal.lock);
489 	bch2_journal_space_available(&c->journal);
490 	spin_unlock(&c->journal.lock);
491 
492 	ret = bch2_journal_reclaim_start(&c->journal);
493 	if (ret)
494 		goto err;
495 
496 	set_bit(BCH_FS_rw, &c->flags);
497 	set_bit(BCH_FS_was_rw, &c->flags);
498 
499 #ifndef BCH_WRITE_REF_DEBUG
500 	percpu_ref_reinit(&c->writes);
501 #else
502 	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++) {
503 		BUG_ON(atomic_long_read(&c->writes[i]));
504 		atomic_long_inc(&c->writes[i]);
505 	}
506 #endif
507 	if (!early) {
508 		ret = bch2_fs_read_write_late(c);
509 		if (ret)
510 			goto err;
511 	}
512 
513 	bch2_do_discards(c);
514 	bch2_do_invalidates(c);
515 	bch2_do_stripe_deletes(c);
516 	bch2_do_pending_node_rewrites(c);
517 	return 0;
518 err:
519 	if (test_bit(BCH_FS_rw, &c->flags))
520 		bch2_fs_read_only(c);
521 	else
522 		__bch2_fs_read_only(c);
523 	return ret;
524 }
525 
526 int bch2_fs_read_write(struct bch_fs *c)
527 {
528 	if (c->opts.recovery_pass_last &&
529 	    c->opts.recovery_pass_last < BCH_RECOVERY_PASS_journal_replay)
530 		return -BCH_ERR_erofs_norecovery;
531 
532 	if (c->opts.nochanges)
533 		return -BCH_ERR_erofs_nochanges;
534 
535 	return __bch2_fs_read_write(c, false);
536 }
537 
538 int bch2_fs_read_write_early(struct bch_fs *c)
539 {
540 	down_write(&c->state_lock);
541 	int ret = __bch2_fs_read_write(c, true);
542 	up_write(&c->state_lock);
543 
544 	return ret;
545 }
546 
547 /* Filesystem startup/shutdown: */
548 
549 static void __bch2_fs_free(struct bch_fs *c)
550 {
551 	for (unsigned i = 0; i < BCH_TIME_STAT_NR; i++)
552 		bch2_time_stats_exit(&c->times[i]);
553 
554 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
555 	bch2_free_pending_node_rewrites(c);
556 	bch2_fs_accounting_exit(c);
557 	bch2_fs_sb_errors_exit(c);
558 	bch2_fs_counters_exit(c);
559 	bch2_fs_snapshots_exit(c);
560 	bch2_fs_quota_exit(c);
561 	bch2_fs_fs_io_direct_exit(c);
562 	bch2_fs_fs_io_buffered_exit(c);
563 	bch2_fs_fsio_exit(c);
564 	bch2_fs_vfs_exit(c);
565 	bch2_fs_ec_exit(c);
566 	bch2_fs_encryption_exit(c);
567 	bch2_fs_nocow_locking_exit(c);
568 	bch2_fs_io_write_exit(c);
569 	bch2_fs_io_read_exit(c);
570 	bch2_fs_buckets_waiting_for_journal_exit(c);
571 	bch2_fs_btree_interior_update_exit(c);
572 	bch2_fs_btree_key_cache_exit(&c->btree_key_cache);
573 	bch2_fs_btree_cache_exit(c);
574 	bch2_fs_btree_iter_exit(c);
575 	bch2_fs_replicas_exit(c);
576 	bch2_fs_journal_exit(&c->journal);
577 	bch2_io_clock_exit(&c->io_clock[WRITE]);
578 	bch2_io_clock_exit(&c->io_clock[READ]);
579 	bch2_fs_compress_exit(c);
580 	bch2_fs_btree_gc_exit(c);
581 	bch2_journal_keys_put_initial(c);
582 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
583 	BUG_ON(atomic_read(&c->journal_keys.ref));
584 	bch2_fs_btree_write_buffer_exit(c);
585 	percpu_free_rwsem(&c->mark_lock);
586 	if (c->online_reserved) {
587 		u64 v = percpu_u64_get(c->online_reserved);
588 		WARN(v, "online_reserved not 0 at shutdown: %lli", v);
589 		free_percpu(c->online_reserved);
590 	}
591 
592 	darray_exit(&c->btree_roots_extra);
593 	free_percpu(c->pcpu);
594 	free_percpu(c->usage);
595 	mempool_exit(&c->large_bkey_pool);
596 	mempool_exit(&c->btree_bounce_pool);
597 	bioset_exit(&c->btree_bio);
598 	mempool_exit(&c->fill_iter);
599 #ifndef BCH_WRITE_REF_DEBUG
600 	percpu_ref_exit(&c->writes);
601 #endif
602 	kfree(rcu_dereference_protected(c->disk_groups, 1));
603 	kfree(c->journal_seq_blacklist_table);
604 
605 	if (c->write_ref_wq)
606 		destroy_workqueue(c->write_ref_wq);
607 	if (c->btree_write_submit_wq)
608 		destroy_workqueue(c->btree_write_submit_wq);
609 	if (c->btree_read_complete_wq)
610 		destroy_workqueue(c->btree_read_complete_wq);
611 	if (c->copygc_wq)
612 		destroy_workqueue(c->copygc_wq);
613 	if (c->btree_io_complete_wq)
614 		destroy_workqueue(c->btree_io_complete_wq);
615 	if (c->btree_update_wq)
616 		destroy_workqueue(c->btree_update_wq);
617 
618 	bch2_free_super(&c->disk_sb);
619 	kvfree(c);
620 	module_put(THIS_MODULE);
621 }
622 
623 static void bch2_fs_release(struct kobject *kobj)
624 {
625 	struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
626 
627 	__bch2_fs_free(c);
628 }
629 
630 void __bch2_fs_stop(struct bch_fs *c)
631 {
632 	bch_verbose(c, "shutting down");
633 
634 	set_bit(BCH_FS_stopping, &c->flags);
635 
636 	down_write(&c->state_lock);
637 	bch2_fs_read_only(c);
638 	up_write(&c->state_lock);
639 
640 	for_each_member_device(c, ca)
641 		bch2_dev_unlink(ca);
642 
643 	if (c->kobj.state_in_sysfs)
644 		kobject_del(&c->kobj);
645 
646 	bch2_fs_debug_exit(c);
647 	bch2_fs_chardev_exit(c);
648 
649 	bch2_ro_ref_put(c);
650 	wait_event(c->ro_ref_wait, !refcount_read(&c->ro_ref));
651 
652 	kobject_put(&c->counters_kobj);
653 	kobject_put(&c->time_stats);
654 	kobject_put(&c->opts_dir);
655 	kobject_put(&c->internal);
656 
657 	/* btree prefetch might have kicked off reads in the background: */
658 	bch2_btree_flush_all_reads(c);
659 
660 	for_each_member_device(c, ca)
661 		cancel_work_sync(&ca->io_error_work);
662 
663 	cancel_work_sync(&c->read_only_work);
664 }
665 
666 void bch2_fs_free(struct bch_fs *c)
667 {
668 	unsigned i;
669 
670 	mutex_lock(&bch_fs_list_lock);
671 	list_del(&c->list);
672 	mutex_unlock(&bch_fs_list_lock);
673 
674 	closure_sync(&c->cl);
675 	closure_debug_destroy(&c->cl);
676 
677 	for (i = 0; i < c->sb.nr_devices; i++) {
678 		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
679 
680 		if (ca) {
681 			EBUG_ON(atomic_long_read(&ca->ref) != 1);
682 			bch2_dev_io_ref_stop(ca, READ);
683 			bch2_free_super(&ca->disk_sb);
684 			bch2_dev_free(ca);
685 		}
686 	}
687 
688 	bch_verbose(c, "shutdown complete");
689 
690 	kobject_put(&c->kobj);
691 }
692 
693 void bch2_fs_stop(struct bch_fs *c)
694 {
695 	__bch2_fs_stop(c);
696 	bch2_fs_free(c);
697 }
698 
699 static int bch2_fs_online(struct bch_fs *c)
700 {
701 	int ret = 0;
702 
703 	lockdep_assert_held(&bch_fs_list_lock);
704 
705 	if (__bch2_uuid_to_fs(c->sb.uuid)) {
706 		bch_err(c, "filesystem UUID already open");
707 		return -EINVAL;
708 	}
709 
710 	ret = bch2_fs_chardev_init(c);
711 	if (ret) {
712 		bch_err(c, "error creating character device");
713 		return ret;
714 	}
715 
716 	bch2_fs_debug_init(c);
717 
718 	ret = kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b) ?:
719 	    kobject_add(&c->internal, &c->kobj, "internal") ?:
720 	    kobject_add(&c->opts_dir, &c->kobj, "options") ?:
721 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
722 	    kobject_add(&c->time_stats, &c->kobj, "time_stats") ?:
723 #endif
724 	    kobject_add(&c->counters_kobj, &c->kobj, "counters") ?:
725 	    bch2_opts_create_sysfs_files(&c->opts_dir, OPT_FS);
726 	if (ret) {
727 		bch_err(c, "error creating sysfs objects");
728 		return ret;
729 	}
730 
731 	down_write(&c->state_lock);
732 
733 	for_each_member_device(c, ca) {
734 		ret = bch2_dev_sysfs_online(c, ca);
735 		if (ret) {
736 			bch_err(c, "error creating sysfs objects");
737 			bch2_dev_put(ca);
738 			goto err;
739 		}
740 	}
741 
742 	BUG_ON(!list_empty(&c->list));
743 	list_add(&c->list, &bch_fs_list);
744 err:
745 	up_write(&c->state_lock);
746 	return ret;
747 }
748 
749 static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
750 {
751 	struct bch_fs *c;
752 	struct printbuf name = PRINTBUF;
753 	unsigned i, iter_size;
754 	int ret = 0;
755 
756 	c = kvmalloc(sizeof(struct bch_fs), GFP_KERNEL|__GFP_ZERO);
757 	if (!c) {
758 		c = ERR_PTR(-BCH_ERR_ENOMEM_fs_alloc);
759 		goto out;
760 	}
761 
762 	c->stdio = (void *)(unsigned long) opts.stdio;
763 
764 	__module_get(THIS_MODULE);
765 
766 	closure_init(&c->cl, NULL);
767 
768 	c->kobj.kset = bcachefs_kset;
769 	kobject_init(&c->kobj, &bch2_fs_ktype);
770 	kobject_init(&c->internal, &bch2_fs_internal_ktype);
771 	kobject_init(&c->opts_dir, &bch2_fs_opts_dir_ktype);
772 	kobject_init(&c->time_stats, &bch2_fs_time_stats_ktype);
773 	kobject_init(&c->counters_kobj, &bch2_fs_counters_ktype);
774 
775 	c->minor		= -1;
776 	c->disk_sb.fs_sb	= true;
777 
778 	init_rwsem(&c->state_lock);
779 	mutex_init(&c->sb_lock);
780 	mutex_init(&c->replicas_gc_lock);
781 	mutex_init(&c->btree_root_lock);
782 	INIT_WORK(&c->read_only_work, bch2_fs_read_only_work);
783 
784 	refcount_set(&c->ro_ref, 1);
785 	init_waitqueue_head(&c->ro_ref_wait);
786 	spin_lock_init(&c->recovery_pass_lock);
787 	sema_init(&c->online_fsck_mutex, 1);
788 
789 	for (i = 0; i < BCH_TIME_STAT_NR; i++)
790 		bch2_time_stats_init(&c->times[i]);
791 
792 	bch2_fs_copygc_init(c);
793 	bch2_fs_btree_key_cache_init_early(&c->btree_key_cache);
794 	bch2_fs_btree_iter_init_early(c);
795 	bch2_fs_btree_interior_update_init_early(c);
796 	bch2_fs_journal_keys_init(c);
797 	bch2_fs_allocator_background_init(c);
798 	bch2_fs_allocator_foreground_init(c);
799 	bch2_fs_rebalance_init(c);
800 	bch2_fs_quota_init(c);
801 	bch2_fs_ec_init_early(c);
802 	bch2_fs_move_init(c);
803 	bch2_fs_sb_errors_init_early(c);
804 
805 	INIT_LIST_HEAD(&c->list);
806 
807 	mutex_init(&c->bio_bounce_pages_lock);
808 	mutex_init(&c->snapshot_table_lock);
809 	init_rwsem(&c->snapshot_create_lock);
810 
811 	spin_lock_init(&c->btree_write_error_lock);
812 
813 	INIT_LIST_HEAD(&c->journal_iters);
814 
815 	INIT_LIST_HEAD(&c->fsck_error_msgs);
816 	mutex_init(&c->fsck_error_msgs_lock);
817 
818 	seqcount_init(&c->usage_lock);
819 
820 	sema_init(&c->io_in_flight, 128);
821 
822 	INIT_LIST_HEAD(&c->vfs_inodes_list);
823 	mutex_init(&c->vfs_inodes_lock);
824 
825 	c->journal.flush_write_time	= &c->times[BCH_TIME_journal_flush_write];
826 	c->journal.noflush_write_time	= &c->times[BCH_TIME_journal_noflush_write];
827 	c->journal.flush_seq_time	= &c->times[BCH_TIME_journal_flush_seq];
828 
829 	bch2_fs_btree_cache_init_early(&c->btree_cache);
830 
831 	mutex_init(&c->sectors_available_lock);
832 
833 	ret = percpu_init_rwsem(&c->mark_lock);
834 	if (ret)
835 		goto err;
836 
837 	mutex_lock(&c->sb_lock);
838 	ret = bch2_sb_to_fs(c, sb);
839 	mutex_unlock(&c->sb_lock);
840 
841 	if (ret)
842 		goto err;
843 
844 #ifdef CONFIG_UNICODE
845 	/* Default encoding until we can potentially have more as an option. */
846 	c->cf_encoding = utf8_load(BCH_FS_DEFAULT_UTF8_ENCODING);
847 	if (IS_ERR(c->cf_encoding)) {
848 		printk(KERN_ERR "Cannot load UTF-8 encoding for filesystem. Version: %u.%u.%u",
849 			unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
850 			unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
851 			unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
852 		ret = -EINVAL;
853 		goto err;
854 	}
855 #else
856 	if (c->sb.features & BIT_ULL(BCH_FEATURE_casefolding)) {
857 		printk(KERN_ERR "Cannot mount a filesystem with casefolding on a kernel without CONFIG_UNICODE\n");
858 		ret = -EINVAL;
859 		goto err;
860 	}
861 #endif
862 
863 	pr_uuid(&name, c->sb.user_uuid.b);
864 	ret = name.allocation_failure ? -BCH_ERR_ENOMEM_fs_name_alloc : 0;
865 	if (ret)
866 		goto err;
867 
868 	strscpy(c->name, name.buf, sizeof(c->name));
869 	printbuf_exit(&name);
870 
871 	/* Compat: */
872 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
873 	    !BCH_SB_JOURNAL_FLUSH_DELAY(sb))
874 		SET_BCH_SB_JOURNAL_FLUSH_DELAY(sb, 1000);
875 
876 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
877 	    !BCH_SB_JOURNAL_RECLAIM_DELAY(sb))
878 		SET_BCH_SB_JOURNAL_RECLAIM_DELAY(sb, 100);
879 
880 	c->opts = bch2_opts_default;
881 	ret = bch2_opts_from_sb(&c->opts, sb);
882 	if (ret)
883 		goto err;
884 
885 	bch2_opts_apply(&c->opts, opts);
886 
887 	c->btree_key_cache_btrees |= 1U << BTREE_ID_alloc;
888 	if (c->opts.inodes_use_key_cache)
889 		c->btree_key_cache_btrees |= 1U << BTREE_ID_inodes;
890 	c->btree_key_cache_btrees |= 1U << BTREE_ID_logged_ops;
891 
892 	c->block_bits		= ilog2(block_sectors(c));
893 	c->btree_foreground_merge_threshold = BTREE_FOREGROUND_MERGE_THRESHOLD(c);
894 
895 	if (bch2_fs_init_fault("fs_alloc")) {
896 		bch_err(c, "fs_alloc fault injected");
897 		ret = -EFAULT;
898 		goto err;
899 	}
900 
901 	iter_size = sizeof(struct sort_iter) +
902 		(btree_blocks(c) + 1) * 2 *
903 		sizeof(struct sort_iter_set);
904 
905 	if (!(c->btree_update_wq = alloc_workqueue("bcachefs",
906 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_UNBOUND, 512)) ||
907 	    !(c->btree_io_complete_wq = alloc_workqueue("bcachefs_btree_io",
908 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
909 	    !(c->copygc_wq = alloc_workqueue("bcachefs_copygc",
910 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 1)) ||
911 	    !(c->btree_read_complete_wq = alloc_workqueue("bcachefs_btree_read_complete",
912 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 512)) ||
913 	    !(c->btree_write_submit_wq = alloc_workqueue("bcachefs_btree_write_sumit",
914 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
915 	    !(c->write_ref_wq = alloc_workqueue("bcachefs_write_ref",
916 				WQ_FREEZABLE, 0)) ||
917 #ifndef BCH_WRITE_REF_DEBUG
918 	    percpu_ref_init(&c->writes, bch2_writes_disabled,
919 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
920 #endif
921 	    mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
922 	    bioset_init(&c->btree_bio, 1,
923 			max(offsetof(struct btree_read_bio, bio),
924 			    offsetof(struct btree_write_bio, wbio.bio)),
925 			BIOSET_NEED_BVECS) ||
926 	    !(c->pcpu = alloc_percpu(struct bch_fs_pcpu)) ||
927 	    !(c->usage = alloc_percpu(struct bch_fs_usage_base)) ||
928 	    !(c->online_reserved = alloc_percpu(u64)) ||
929 	    mempool_init_kvmalloc_pool(&c->btree_bounce_pool, 1,
930 				       c->opts.btree_node_size) ||
931 	    mempool_init_kmalloc_pool(&c->large_bkey_pool, 1, 2048)) {
932 		ret = -BCH_ERR_ENOMEM_fs_other_alloc;
933 		goto err;
934 	}
935 
936 	ret = bch2_fs_counters_init(c) ?:
937 	    bch2_fs_sb_errors_init(c) ?:
938 	    bch2_io_clock_init(&c->io_clock[READ]) ?:
939 	    bch2_io_clock_init(&c->io_clock[WRITE]) ?:
940 	    bch2_fs_journal_init(&c->journal) ?:
941 	    bch2_fs_btree_iter_init(c) ?:
942 	    bch2_fs_btree_cache_init(c) ?:
943 	    bch2_fs_btree_key_cache_init(&c->btree_key_cache) ?:
944 	    bch2_fs_btree_interior_update_init(c) ?:
945 	    bch2_fs_btree_gc_init(c) ?:
946 	    bch2_fs_buckets_waiting_for_journal_init(c) ?:
947 	    bch2_fs_btree_write_buffer_init(c) ?:
948 	    bch2_fs_subvolumes_init(c) ?:
949 	    bch2_fs_io_read_init(c) ?:
950 	    bch2_fs_io_write_init(c) ?:
951 	    bch2_fs_nocow_locking_init(c) ?:
952 	    bch2_fs_encryption_init(c) ?:
953 	    bch2_fs_compress_init(c) ?:
954 	    bch2_fs_ec_init(c) ?:
955 	    bch2_fs_vfs_init(c) ?:
956 	    bch2_fs_fsio_init(c) ?:
957 	    bch2_fs_fs_io_buffered_init(c) ?:
958 	    bch2_fs_fs_io_direct_init(c);
959 	if (ret)
960 		goto err;
961 
962 	for (i = 0; i < c->sb.nr_devices; i++) {
963 		if (!bch2_member_exists(c->disk_sb.sb, i))
964 			continue;
965 		ret = bch2_dev_alloc(c, i);
966 		if (ret)
967 			goto err;
968 	}
969 
970 	bch2_journal_entry_res_resize(&c->journal,
971 			&c->btree_root_journal_res,
972 			BTREE_ID_NR * (JSET_KEYS_U64s + BKEY_BTREE_PTR_U64s_MAX));
973 	bch2_journal_entry_res_resize(&c->journal,
974 			&c->clock_journal_res,
975 			(sizeof(struct jset_entry_clock) / sizeof(u64)) * 2);
976 
977 	mutex_lock(&bch_fs_list_lock);
978 	ret = bch2_fs_online(c);
979 	mutex_unlock(&bch_fs_list_lock);
980 
981 	if (ret)
982 		goto err;
983 out:
984 	return c;
985 err:
986 	bch2_fs_free(c);
987 	c = ERR_PTR(ret);
988 	goto out;
989 }
990 
991 noinline_for_stack
992 static void print_mount_opts(struct bch_fs *c)
993 {
994 	enum bch_opt_id i;
995 	struct printbuf p = PRINTBUF;
996 	bool first = true;
997 
998 	prt_str(&p, "starting version ");
999 	bch2_version_to_text(&p, c->sb.version);
1000 
1001 	for (i = 0; i < bch2_opts_nr; i++) {
1002 		const struct bch_option *opt = &bch2_opt_table[i];
1003 		u64 v = bch2_opt_get_by_id(&c->opts, i);
1004 
1005 		if (!(opt->flags & OPT_MOUNT))
1006 			continue;
1007 
1008 		if (v == bch2_opt_get_by_id(&bch2_opts_default, i))
1009 			continue;
1010 
1011 		prt_str(&p, first ? " opts=" : ",");
1012 		first = false;
1013 		bch2_opt_to_text(&p, c, c->disk_sb.sb, opt, v, OPT_SHOW_MOUNT_STYLE);
1014 	}
1015 
1016 	bch_info(c, "%s", p.buf);
1017 	printbuf_exit(&p);
1018 }
1019 
1020 int bch2_fs_start(struct bch_fs *c)
1021 {
1022 	time64_t now = ktime_get_real_seconds();
1023 	int ret = 0;
1024 
1025 	print_mount_opts(c);
1026 
1027 	down_write(&c->state_lock);
1028 	mutex_lock(&c->sb_lock);
1029 
1030 	BUG_ON(test_bit(BCH_FS_started, &c->flags));
1031 
1032 	if (!bch2_sb_field_get_minsize(&c->disk_sb, ext,
1033 			sizeof(struct bch_sb_field_ext) / sizeof(u64))) {
1034 		mutex_unlock(&c->sb_lock);
1035 		up_write(&c->state_lock);
1036 		ret = -BCH_ERR_ENOSPC_sb;
1037 		goto err;
1038 	}
1039 
1040 	ret = bch2_sb_members_v2_init(c);
1041 	if (ret) {
1042 		mutex_unlock(&c->sb_lock);
1043 		up_write(&c->state_lock);
1044 		goto err;
1045 	}
1046 
1047 	for_each_online_member(c, ca)
1048 		bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount = cpu_to_le64(now);
1049 
1050 	mutex_unlock(&c->sb_lock);
1051 
1052 	for_each_rw_member(c, ca)
1053 		bch2_dev_allocator_add(c, ca);
1054 	bch2_recalc_capacity(c);
1055 	up_write(&c->state_lock);
1056 
1057 	c->recovery_task = current;
1058 	ret = BCH_SB_INITIALIZED(c->disk_sb.sb)
1059 		? bch2_fs_recovery(c)
1060 		: bch2_fs_initialize(c);
1061 	c->recovery_task = NULL;
1062 
1063 	if (ret)
1064 		goto err;
1065 
1066 	ret = bch2_opts_check_may_set(c);
1067 	if (ret)
1068 		goto err;
1069 
1070 	if (bch2_fs_init_fault("fs_start")) {
1071 		ret = -BCH_ERR_injected_fs_start;
1072 		goto err;
1073 	}
1074 
1075 	set_bit(BCH_FS_started, &c->flags);
1076 	wake_up(&c->ro_ref_wait);
1077 
1078 	down_write(&c->state_lock);
1079 	if (c->opts.read_only) {
1080 		bch2_fs_read_only(c);
1081 	} else {
1082 		ret = !test_bit(BCH_FS_rw, &c->flags)
1083 			? bch2_fs_read_write(c)
1084 			: bch2_fs_read_write_late(c);
1085 	}
1086 	up_write(&c->state_lock);
1087 
1088 err:
1089 	if (ret)
1090 		bch_err_msg(c, ret, "starting filesystem");
1091 	else
1092 		bch_verbose(c, "done starting filesystem");
1093 	return ret;
1094 }
1095 
1096 static int bch2_dev_may_add(struct bch_sb *sb, struct bch_fs *c)
1097 {
1098 	struct bch_member m = bch2_sb_member_get(sb, sb->dev_idx);
1099 
1100 	if (le16_to_cpu(sb->block_size) != block_sectors(c))
1101 		return -BCH_ERR_mismatched_block_size;
1102 
1103 	if (le16_to_cpu(m.bucket_size) <
1104 	    BCH_SB_BTREE_NODE_SIZE(c->disk_sb.sb))
1105 		return -BCH_ERR_bucket_size_too_small;
1106 
1107 	return 0;
1108 }
1109 
1110 static int bch2_dev_in_fs(struct bch_sb_handle *fs,
1111 			  struct bch_sb_handle *sb,
1112 			  struct bch_opts *opts)
1113 {
1114 	if (fs == sb)
1115 		return 0;
1116 
1117 	if (!uuid_equal(&fs->sb->uuid, &sb->sb->uuid))
1118 		return -BCH_ERR_device_not_a_member_of_filesystem;
1119 
1120 	if (!bch2_member_exists(fs->sb, sb->sb->dev_idx))
1121 		return -BCH_ERR_device_has_been_removed;
1122 
1123 	if (fs->sb->block_size != sb->sb->block_size)
1124 		return -BCH_ERR_mismatched_block_size;
1125 
1126 	if (le16_to_cpu(fs->sb->version) < bcachefs_metadata_version_member_seq ||
1127 	    le16_to_cpu(sb->sb->version) < bcachefs_metadata_version_member_seq)
1128 		return 0;
1129 
1130 	if (fs->sb->seq == sb->sb->seq &&
1131 	    fs->sb->write_time != sb->sb->write_time) {
1132 		struct printbuf buf = PRINTBUF;
1133 
1134 		prt_str(&buf, "Split brain detected between ");
1135 		prt_bdevname(&buf, sb->bdev);
1136 		prt_str(&buf, " and ");
1137 		prt_bdevname(&buf, fs->bdev);
1138 		prt_char(&buf, ':');
1139 		prt_newline(&buf);
1140 		prt_printf(&buf, "seq=%llu but write_time different, got", le64_to_cpu(sb->sb->seq));
1141 		prt_newline(&buf);
1142 
1143 		prt_bdevname(&buf, fs->bdev);
1144 		prt_char(&buf, ' ');
1145 		bch2_prt_datetime(&buf, le64_to_cpu(fs->sb->write_time));
1146 		prt_newline(&buf);
1147 
1148 		prt_bdevname(&buf, sb->bdev);
1149 		prt_char(&buf, ' ');
1150 		bch2_prt_datetime(&buf, le64_to_cpu(sb->sb->write_time));
1151 		prt_newline(&buf);
1152 
1153 		if (!opts->no_splitbrain_check)
1154 			prt_printf(&buf, "Not using older sb");
1155 
1156 		pr_err("%s", buf.buf);
1157 		printbuf_exit(&buf);
1158 
1159 		if (!opts->no_splitbrain_check)
1160 			return -BCH_ERR_device_splitbrain;
1161 	}
1162 
1163 	struct bch_member m = bch2_sb_member_get(fs->sb, sb->sb->dev_idx);
1164 	u64 seq_from_fs		= le64_to_cpu(m.seq);
1165 	u64 seq_from_member	= le64_to_cpu(sb->sb->seq);
1166 
1167 	if (seq_from_fs && seq_from_fs < seq_from_member) {
1168 		struct printbuf buf = PRINTBUF;
1169 
1170 		prt_str(&buf, "Split brain detected between ");
1171 		prt_bdevname(&buf, sb->bdev);
1172 		prt_str(&buf, " and ");
1173 		prt_bdevname(&buf, fs->bdev);
1174 		prt_char(&buf, ':');
1175 		prt_newline(&buf);
1176 
1177 		prt_bdevname(&buf, fs->bdev);
1178 		prt_str(&buf, " believes seq of ");
1179 		prt_bdevname(&buf, sb->bdev);
1180 		prt_printf(&buf, " to be %llu, but ", seq_from_fs);
1181 		prt_bdevname(&buf, sb->bdev);
1182 		prt_printf(&buf, " has %llu\n", seq_from_member);
1183 
1184 		if (!opts->no_splitbrain_check) {
1185 			prt_str(&buf, "Not using ");
1186 			prt_bdevname(&buf, sb->bdev);
1187 		}
1188 
1189 		pr_err("%s", buf.buf);
1190 		printbuf_exit(&buf);
1191 
1192 		if (!opts->no_splitbrain_check)
1193 			return -BCH_ERR_device_splitbrain;
1194 	}
1195 
1196 	return 0;
1197 }
1198 
1199 /* Device startup/shutdown: */
1200 
1201 static void bch2_dev_io_ref_stop(struct bch_dev *ca, int rw)
1202 {
1203 	if (!percpu_ref_is_zero(&ca->io_ref[rw])) {
1204 		reinit_completion(&ca->io_ref_completion[rw]);
1205 		percpu_ref_kill(&ca->io_ref[rw]);
1206 		wait_for_completion(&ca->io_ref_completion[rw]);
1207 	}
1208 }
1209 
1210 static void bch2_dev_release(struct kobject *kobj)
1211 {
1212 	struct bch_dev *ca = container_of(kobj, struct bch_dev, kobj);
1213 
1214 	kfree(ca);
1215 }
1216 
1217 static void bch2_dev_free(struct bch_dev *ca)
1218 {
1219 	WARN_ON(!percpu_ref_is_zero(&ca->io_ref[WRITE]));
1220 	WARN_ON(!percpu_ref_is_zero(&ca->io_ref[READ]));
1221 
1222 	cancel_work_sync(&ca->io_error_work);
1223 
1224 	bch2_dev_unlink(ca);
1225 
1226 	if (ca->kobj.state_in_sysfs)
1227 		kobject_del(&ca->kobj);
1228 
1229 	bch2_free_super(&ca->disk_sb);
1230 	bch2_dev_allocator_background_exit(ca);
1231 	bch2_dev_journal_exit(ca);
1232 
1233 	free_percpu(ca->io_done);
1234 	bch2_dev_buckets_free(ca);
1235 	kfree(ca->sb_read_scratch);
1236 
1237 	bch2_time_stats_quantiles_exit(&ca->io_latency[WRITE]);
1238 	bch2_time_stats_quantiles_exit(&ca->io_latency[READ]);
1239 
1240 	percpu_ref_exit(&ca->io_ref[WRITE]);
1241 	percpu_ref_exit(&ca->io_ref[READ]);
1242 #ifndef CONFIG_BCACHEFS_DEBUG
1243 	percpu_ref_exit(&ca->ref);
1244 #endif
1245 	kobject_put(&ca->kobj);
1246 }
1247 
1248 static void __bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca)
1249 {
1250 
1251 	lockdep_assert_held(&c->state_lock);
1252 
1253 	if (percpu_ref_is_zero(&ca->io_ref[READ]))
1254 		return;
1255 
1256 	__bch2_dev_read_only(c, ca);
1257 
1258 	bch2_dev_io_ref_stop(ca, READ);
1259 
1260 	bch2_dev_unlink(ca);
1261 
1262 	bch2_free_super(&ca->disk_sb);
1263 	bch2_dev_journal_exit(ca);
1264 }
1265 
1266 #ifndef CONFIG_BCACHEFS_DEBUG
1267 static void bch2_dev_ref_complete(struct percpu_ref *ref)
1268 {
1269 	struct bch_dev *ca = container_of(ref, struct bch_dev, ref);
1270 
1271 	complete(&ca->ref_completion);
1272 }
1273 #endif
1274 
1275 static void bch2_dev_io_ref_read_complete(struct percpu_ref *ref)
1276 {
1277 	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref[READ]);
1278 
1279 	complete(&ca->io_ref_completion[READ]);
1280 }
1281 
1282 static void bch2_dev_io_ref_write_complete(struct percpu_ref *ref)
1283 {
1284 	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref[WRITE]);
1285 
1286 	complete(&ca->io_ref_completion[WRITE]);
1287 }
1288 
1289 static void bch2_dev_unlink(struct bch_dev *ca)
1290 {
1291 	struct kobject *b;
1292 
1293 	/*
1294 	 * This is racy w.r.t. the underlying block device being hot-removed,
1295 	 * which removes it from sysfs.
1296 	 *
1297 	 * It'd be lovely if we had a way to handle this race, but the sysfs
1298 	 * code doesn't appear to provide a good method and block/holder.c is
1299 	 * susceptible as well:
1300 	 */
1301 	if (ca->kobj.state_in_sysfs &&
1302 	    ca->disk_sb.bdev &&
1303 	    (b = bdev_kobj(ca->disk_sb.bdev))->state_in_sysfs) {
1304 		sysfs_remove_link(b, "bcachefs");
1305 		sysfs_remove_link(&ca->kobj, "block");
1306 	}
1307 }
1308 
1309 static int bch2_dev_sysfs_online(struct bch_fs *c, struct bch_dev *ca)
1310 {
1311 	int ret;
1312 
1313 	if (!c->kobj.state_in_sysfs)
1314 		return 0;
1315 
1316 	if (!ca->kobj.state_in_sysfs) {
1317 		ret =   kobject_add(&ca->kobj, &c->kobj, "dev-%u", ca->dev_idx) ?:
1318 			bch2_opts_create_sysfs_files(&ca->kobj, OPT_DEVICE);
1319 		if (ret)
1320 			return ret;
1321 	}
1322 
1323 	if (ca->disk_sb.bdev) {
1324 		struct kobject *block = bdev_kobj(ca->disk_sb.bdev);
1325 
1326 		ret = sysfs_create_link(block, &ca->kobj, "bcachefs");
1327 		if (ret)
1328 			return ret;
1329 
1330 		ret = sysfs_create_link(&ca->kobj, block, "block");
1331 		if (ret)
1332 			return ret;
1333 	}
1334 
1335 	return 0;
1336 }
1337 
1338 static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
1339 					struct bch_member *member)
1340 {
1341 	struct bch_dev *ca;
1342 	unsigned i;
1343 
1344 	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
1345 	if (!ca)
1346 		return NULL;
1347 
1348 	kobject_init(&ca->kobj, &bch2_dev_ktype);
1349 	init_completion(&ca->ref_completion);
1350 	init_completion(&ca->io_ref_completion[READ]);
1351 	init_completion(&ca->io_ref_completion[WRITE]);
1352 
1353 	INIT_WORK(&ca->io_error_work, bch2_io_error_work);
1354 
1355 	bch2_time_stats_quantiles_init(&ca->io_latency[READ]);
1356 	bch2_time_stats_quantiles_init(&ca->io_latency[WRITE]);
1357 
1358 	ca->mi = bch2_mi_to_cpu(member);
1359 
1360 	for (i = 0; i < ARRAY_SIZE(member->errors); i++)
1361 		atomic64_set(&ca->errors[i], le64_to_cpu(member->errors[i]));
1362 
1363 	ca->uuid = member->uuid;
1364 
1365 	ca->nr_btree_reserve = DIV_ROUND_UP(BTREE_NODE_RESERVE,
1366 			     ca->mi.bucket_size / btree_sectors(c));
1367 
1368 #ifndef CONFIG_BCACHEFS_DEBUG
1369 	if (percpu_ref_init(&ca->ref, bch2_dev_ref_complete, 0, GFP_KERNEL))
1370 		goto err;
1371 #else
1372 	atomic_long_set(&ca->ref, 1);
1373 #endif
1374 
1375 	bch2_dev_allocator_background_init(ca);
1376 
1377 	if (percpu_ref_init(&ca->io_ref[READ], bch2_dev_io_ref_read_complete,
1378 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
1379 	    percpu_ref_init(&ca->io_ref[WRITE], bch2_dev_io_ref_write_complete,
1380 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
1381 	    !(ca->sb_read_scratch = kmalloc(BCH_SB_READ_SCRATCH_BUF_SIZE, GFP_KERNEL)) ||
1382 	    bch2_dev_buckets_alloc(c, ca) ||
1383 	    !(ca->io_done	= alloc_percpu(*ca->io_done)))
1384 		goto err;
1385 
1386 	return ca;
1387 err:
1388 	bch2_dev_free(ca);
1389 	return NULL;
1390 }
1391 
1392 static void bch2_dev_attach(struct bch_fs *c, struct bch_dev *ca,
1393 			    unsigned dev_idx)
1394 {
1395 	ca->dev_idx = dev_idx;
1396 	__set_bit(ca->dev_idx, ca->self.d);
1397 	scnprintf(ca->name, sizeof(ca->name), "dev-%u", dev_idx);
1398 
1399 	ca->fs = c;
1400 	rcu_assign_pointer(c->devs[ca->dev_idx], ca);
1401 
1402 	if (bch2_dev_sysfs_online(c, ca))
1403 		pr_warn("error creating sysfs objects");
1404 }
1405 
1406 static int bch2_dev_alloc(struct bch_fs *c, unsigned dev_idx)
1407 {
1408 	struct bch_member member = bch2_sb_member_get(c->disk_sb.sb, dev_idx);
1409 	struct bch_dev *ca = NULL;
1410 
1411 	if (bch2_fs_init_fault("dev_alloc"))
1412 		goto err;
1413 
1414 	ca = __bch2_dev_alloc(c, &member);
1415 	if (!ca)
1416 		goto err;
1417 
1418 	ca->fs = c;
1419 
1420 	bch2_dev_attach(c, ca, dev_idx);
1421 	return 0;
1422 err:
1423 	return -BCH_ERR_ENOMEM_dev_alloc;
1424 }
1425 
1426 static int __bch2_dev_attach_bdev(struct bch_dev *ca, struct bch_sb_handle *sb)
1427 {
1428 	unsigned ret;
1429 
1430 	if (bch2_dev_is_online(ca)) {
1431 		bch_err(ca, "already have device online in slot %u",
1432 			sb->sb->dev_idx);
1433 		return -BCH_ERR_device_already_online;
1434 	}
1435 
1436 	if (get_capacity(sb->bdev->bd_disk) <
1437 	    ca->mi.bucket_size * ca->mi.nbuckets) {
1438 		bch_err(ca, "cannot online: device too small");
1439 		return -BCH_ERR_device_size_too_small;
1440 	}
1441 
1442 	BUG_ON(!percpu_ref_is_zero(&ca->io_ref[READ]));
1443 	BUG_ON(!percpu_ref_is_zero(&ca->io_ref[WRITE]));
1444 
1445 	ret = bch2_dev_journal_init(ca, sb->sb);
1446 	if (ret)
1447 		return ret;
1448 
1449 	/* Commit: */
1450 	ca->disk_sb = *sb;
1451 	memset(sb, 0, sizeof(*sb));
1452 
1453 	/*
1454 	 * Stash pointer to the filesystem for blk_holder_ops - note that once
1455 	 * attached to a filesystem, we will always close the block device
1456 	 * before tearing down the filesystem object.
1457 	 */
1458 	ca->disk_sb.holder->c = ca->fs;
1459 
1460 	ca->dev = ca->disk_sb.bdev->bd_dev;
1461 
1462 	percpu_ref_reinit(&ca->io_ref[READ]);
1463 
1464 	return 0;
1465 }
1466 
1467 static int bch2_dev_attach_bdev(struct bch_fs *c, struct bch_sb_handle *sb)
1468 {
1469 	struct bch_dev *ca;
1470 	int ret;
1471 
1472 	lockdep_assert_held(&c->state_lock);
1473 
1474 	if (le64_to_cpu(sb->sb->seq) >
1475 	    le64_to_cpu(c->disk_sb.sb->seq))
1476 		bch2_sb_to_fs(c, sb->sb);
1477 
1478 	BUG_ON(!bch2_dev_exists(c, sb->sb->dev_idx));
1479 
1480 	ca = bch2_dev_locked(c, sb->sb->dev_idx);
1481 
1482 	ret = __bch2_dev_attach_bdev(ca, sb);
1483 	if (ret)
1484 		return ret;
1485 
1486 	bch2_dev_sysfs_online(c, ca);
1487 
1488 	struct printbuf name = PRINTBUF;
1489 	prt_bdevname(&name, ca->disk_sb.bdev);
1490 
1491 	if (c->sb.nr_devices == 1)
1492 		strscpy(c->name, name.buf, sizeof(c->name));
1493 	strscpy(ca->name, name.buf, sizeof(ca->name));
1494 
1495 	printbuf_exit(&name);
1496 
1497 	rebalance_wakeup(c);
1498 	return 0;
1499 }
1500 
1501 /* Device management: */
1502 
1503 /*
1504  * Note: this function is also used by the error paths - when a particular
1505  * device sees an error, we call it to determine whether we can just set the
1506  * device RO, or - if this function returns false - we'll set the whole
1507  * filesystem RO:
1508  *
1509  * XXX: maybe we should be more explicit about whether we're changing state
1510  * because we got an error or what have you?
1511  */
1512 bool bch2_dev_state_allowed(struct bch_fs *c, struct bch_dev *ca,
1513 			    enum bch_member_state new_state, int flags)
1514 {
1515 	struct bch_devs_mask new_online_devs;
1516 	int nr_rw = 0, required;
1517 
1518 	lockdep_assert_held(&c->state_lock);
1519 
1520 	switch (new_state) {
1521 	case BCH_MEMBER_STATE_rw:
1522 		return true;
1523 	case BCH_MEMBER_STATE_ro:
1524 		if (ca->mi.state != BCH_MEMBER_STATE_rw)
1525 			return true;
1526 
1527 		/* do we have enough devices to write to?  */
1528 		for_each_member_device(c, ca2)
1529 			if (ca2 != ca)
1530 				nr_rw += ca2->mi.state == BCH_MEMBER_STATE_rw;
1531 
1532 		required = max(!(flags & BCH_FORCE_IF_METADATA_DEGRADED)
1533 			       ? c->opts.metadata_replicas
1534 			       : metadata_replicas_required(c),
1535 			       !(flags & BCH_FORCE_IF_DATA_DEGRADED)
1536 			       ? c->opts.data_replicas
1537 			       : data_replicas_required(c));
1538 
1539 		return nr_rw >= required;
1540 	case BCH_MEMBER_STATE_failed:
1541 	case BCH_MEMBER_STATE_spare:
1542 		if (ca->mi.state != BCH_MEMBER_STATE_rw &&
1543 		    ca->mi.state != BCH_MEMBER_STATE_ro)
1544 			return true;
1545 
1546 		/* do we have enough devices to read from?  */
1547 		new_online_devs = bch2_online_devs(c);
1548 		__clear_bit(ca->dev_idx, new_online_devs.d);
1549 
1550 		return bch2_have_enough_devs(c, new_online_devs, flags, false);
1551 	default:
1552 		BUG();
1553 	}
1554 }
1555 
1556 static bool bch2_fs_may_start(struct bch_fs *c)
1557 {
1558 	struct bch_dev *ca;
1559 	unsigned i, flags = 0;
1560 
1561 	if (c->opts.very_degraded)
1562 		flags |= BCH_FORCE_IF_DEGRADED|BCH_FORCE_IF_LOST;
1563 
1564 	if (c->opts.degraded)
1565 		flags |= BCH_FORCE_IF_DEGRADED;
1566 
1567 	if (!c->opts.degraded &&
1568 	    !c->opts.very_degraded) {
1569 		mutex_lock(&c->sb_lock);
1570 
1571 		for (i = 0; i < c->disk_sb.sb->nr_devices; i++) {
1572 			if (!bch2_member_exists(c->disk_sb.sb, i))
1573 				continue;
1574 
1575 			ca = bch2_dev_locked(c, i);
1576 
1577 			if (!bch2_dev_is_online(ca) &&
1578 			    (ca->mi.state == BCH_MEMBER_STATE_rw ||
1579 			     ca->mi.state == BCH_MEMBER_STATE_ro)) {
1580 				mutex_unlock(&c->sb_lock);
1581 				return false;
1582 			}
1583 		}
1584 		mutex_unlock(&c->sb_lock);
1585 	}
1586 
1587 	return bch2_have_enough_devs(c, bch2_online_devs(c), flags, true);
1588 }
1589 
1590 static void __bch2_dev_read_only(struct bch_fs *c, struct bch_dev *ca)
1591 {
1592 	bch2_dev_io_ref_stop(ca, WRITE);
1593 
1594 	/*
1595 	 * The allocator thread itself allocates btree nodes, so stop it first:
1596 	 */
1597 	bch2_dev_allocator_remove(c, ca);
1598 	bch2_recalc_capacity(c);
1599 	bch2_dev_journal_stop(&c->journal, ca);
1600 }
1601 
1602 static void __bch2_dev_read_write(struct bch_fs *c, struct bch_dev *ca)
1603 {
1604 	lockdep_assert_held(&c->state_lock);
1605 
1606 	BUG_ON(ca->mi.state != BCH_MEMBER_STATE_rw);
1607 
1608 	bch2_dev_allocator_add(c, ca);
1609 	bch2_recalc_capacity(c);
1610 
1611 	if (percpu_ref_is_zero(&ca->io_ref[WRITE]))
1612 		percpu_ref_reinit(&ca->io_ref[WRITE]);
1613 
1614 	bch2_dev_do_discards(ca);
1615 }
1616 
1617 int __bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1618 			 enum bch_member_state new_state, int flags)
1619 {
1620 	struct bch_member *m;
1621 	int ret = 0;
1622 
1623 	if (ca->mi.state == new_state)
1624 		return 0;
1625 
1626 	if (!bch2_dev_state_allowed(c, ca, new_state, flags))
1627 		return -BCH_ERR_device_state_not_allowed;
1628 
1629 	if (new_state != BCH_MEMBER_STATE_rw)
1630 		__bch2_dev_read_only(c, ca);
1631 
1632 	bch_notice(ca, "%s", bch2_member_states[new_state]);
1633 
1634 	mutex_lock(&c->sb_lock);
1635 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
1636 	SET_BCH_MEMBER_STATE(m, new_state);
1637 	bch2_write_super(c);
1638 	mutex_unlock(&c->sb_lock);
1639 
1640 	if (new_state == BCH_MEMBER_STATE_rw)
1641 		__bch2_dev_read_write(c, ca);
1642 
1643 	rebalance_wakeup(c);
1644 
1645 	return ret;
1646 }
1647 
1648 int bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1649 		       enum bch_member_state new_state, int flags)
1650 {
1651 	int ret;
1652 
1653 	down_write(&c->state_lock);
1654 	ret = __bch2_dev_set_state(c, ca, new_state, flags);
1655 	up_write(&c->state_lock);
1656 
1657 	return ret;
1658 }
1659 
1660 /* Device add/removal: */
1661 
1662 int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
1663 {
1664 	struct bch_member *m;
1665 	unsigned dev_idx = ca->dev_idx, data;
1666 	int ret;
1667 
1668 	down_write(&c->state_lock);
1669 
1670 	/*
1671 	 * We consume a reference to ca->ref, regardless of whether we succeed
1672 	 * or fail:
1673 	 */
1674 	bch2_dev_put(ca);
1675 
1676 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1677 		bch_err(ca, "Cannot remove without losing data");
1678 		ret = -BCH_ERR_device_state_not_allowed;
1679 		goto err;
1680 	}
1681 
1682 	__bch2_dev_read_only(c, ca);
1683 
1684 	ret = bch2_dev_data_drop(c, ca->dev_idx, flags);
1685 	bch_err_msg(ca, ret, "bch2_dev_data_drop()");
1686 	if (ret)
1687 		goto err;
1688 
1689 	ret = bch2_dev_remove_alloc(c, ca);
1690 	bch_err_msg(ca, ret, "bch2_dev_remove_alloc()");
1691 	if (ret)
1692 		goto err;
1693 
1694 	/*
1695 	 * We need to flush the entire journal to get rid of keys that reference
1696 	 * the device being removed before removing the superblock entry
1697 	 */
1698 	bch2_journal_flush_all_pins(&c->journal);
1699 
1700 	/*
1701 	 * this is really just needed for the bch2_replicas_gc_(start|end)
1702 	 * calls, and could be cleaned up:
1703 	 */
1704 	ret = bch2_journal_flush_device_pins(&c->journal, ca->dev_idx);
1705 	bch_err_msg(ca, ret, "bch2_journal_flush_device_pins()");
1706 	if (ret)
1707 		goto err;
1708 
1709 	ret = bch2_journal_flush(&c->journal);
1710 	bch_err_msg(ca, ret, "bch2_journal_flush()");
1711 	if (ret)
1712 		goto err;
1713 
1714 	ret = bch2_replicas_gc2(c);
1715 	bch_err_msg(ca, ret, "bch2_replicas_gc2()");
1716 	if (ret)
1717 		goto err;
1718 
1719 	data = bch2_dev_has_data(c, ca);
1720 	if (data) {
1721 		struct printbuf data_has = PRINTBUF;
1722 
1723 		prt_bitflags(&data_has, __bch2_data_types, data);
1724 		bch_err(ca, "Remove failed, still has data (%s)", data_has.buf);
1725 		printbuf_exit(&data_has);
1726 		ret = -EBUSY;
1727 		goto err;
1728 	}
1729 
1730 	__bch2_dev_offline(c, ca);
1731 
1732 	mutex_lock(&c->sb_lock);
1733 	rcu_assign_pointer(c->devs[ca->dev_idx], NULL);
1734 	mutex_unlock(&c->sb_lock);
1735 
1736 #ifndef CONFIG_BCACHEFS_DEBUG
1737 	percpu_ref_kill(&ca->ref);
1738 #else
1739 	ca->dying = true;
1740 	bch2_dev_put(ca);
1741 #endif
1742 	wait_for_completion(&ca->ref_completion);
1743 
1744 	bch2_dev_free(ca);
1745 
1746 	/*
1747 	 * Free this device's slot in the bch_member array - all pointers to
1748 	 * this device must be gone:
1749 	 */
1750 	mutex_lock(&c->sb_lock);
1751 	m = bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx);
1752 	memset(&m->uuid, 0, sizeof(m->uuid));
1753 
1754 	bch2_write_super(c);
1755 
1756 	mutex_unlock(&c->sb_lock);
1757 	up_write(&c->state_lock);
1758 	return 0;
1759 err:
1760 	if (ca->mi.state == BCH_MEMBER_STATE_rw &&
1761 	    !percpu_ref_is_zero(&ca->io_ref[READ]))
1762 		__bch2_dev_read_write(c, ca);
1763 	up_write(&c->state_lock);
1764 	return ret;
1765 }
1766 
1767 /* Add new device to running filesystem: */
1768 int bch2_dev_add(struct bch_fs *c, const char *path)
1769 {
1770 	struct bch_opts opts = bch2_opts_empty();
1771 	struct bch_sb_handle sb;
1772 	struct bch_dev *ca = NULL;
1773 	struct printbuf errbuf = PRINTBUF;
1774 	struct printbuf label = PRINTBUF;
1775 	int ret;
1776 
1777 	ret = bch2_read_super(path, &opts, &sb);
1778 	bch_err_msg(c, ret, "reading super");
1779 	if (ret)
1780 		goto err;
1781 
1782 	struct bch_member dev_mi = bch2_sb_member_get(sb.sb, sb.sb->dev_idx);
1783 
1784 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1785 		bch2_disk_path_to_text_sb(&label, sb.sb, BCH_MEMBER_GROUP(&dev_mi) - 1);
1786 		if (label.allocation_failure) {
1787 			ret = -ENOMEM;
1788 			goto err;
1789 		}
1790 	}
1791 
1792 	ret = bch2_dev_may_add(sb.sb, c);
1793 	if (ret)
1794 		goto err;
1795 
1796 	ca = __bch2_dev_alloc(c, &dev_mi);
1797 	if (!ca) {
1798 		ret = -ENOMEM;
1799 		goto err;
1800 	}
1801 
1802 	ret = __bch2_dev_attach_bdev(ca, &sb);
1803 	if (ret)
1804 		goto err;
1805 
1806 	down_write(&c->state_lock);
1807 	mutex_lock(&c->sb_lock);
1808 
1809 	ret = bch2_sb_from_fs(c, ca);
1810 	bch_err_msg(c, ret, "setting up new superblock");
1811 	if (ret)
1812 		goto err_unlock;
1813 
1814 	if (dynamic_fault("bcachefs:add:no_slot"))
1815 		goto err_unlock;
1816 
1817 	ret = bch2_sb_member_alloc(c);
1818 	if (ret < 0) {
1819 		bch_err_msg(c, ret, "setting up new superblock");
1820 		goto err_unlock;
1821 	}
1822 	unsigned dev_idx = ret;
1823 
1824 	/* success: */
1825 
1826 	dev_mi.last_mount = cpu_to_le64(ktime_get_real_seconds());
1827 	*bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx) = dev_mi;
1828 
1829 	ca->disk_sb.sb->dev_idx	= dev_idx;
1830 	bch2_dev_attach(c, ca, dev_idx);
1831 
1832 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1833 		ret = __bch2_dev_group_set(c, ca, label.buf);
1834 		bch_err_msg(c, ret, "creating new label");
1835 		if (ret)
1836 			goto err_unlock;
1837 	}
1838 
1839 	bch2_write_super(c);
1840 	mutex_unlock(&c->sb_lock);
1841 
1842 	ret = bch2_dev_usage_init(ca, false);
1843 	if (ret)
1844 		goto err_late;
1845 
1846 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1847 	bch_err_msg(ca, ret, "marking new superblock");
1848 	if (ret)
1849 		goto err_late;
1850 
1851 	ret = bch2_fs_freespace_init(c);
1852 	bch_err_msg(ca, ret, "initializing free space");
1853 	if (ret)
1854 		goto err_late;
1855 
1856 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1857 		__bch2_dev_read_write(c, ca);
1858 
1859 	ret = bch2_dev_journal_alloc(ca, false);
1860 	bch_err_msg(c, ret, "allocating journal");
1861 	if (ret)
1862 		goto err_late;
1863 
1864 	up_write(&c->state_lock);
1865 out:
1866 	printbuf_exit(&label);
1867 	printbuf_exit(&errbuf);
1868 	bch_err_fn(c, ret);
1869 	return ret;
1870 
1871 err_unlock:
1872 	mutex_unlock(&c->sb_lock);
1873 	up_write(&c->state_lock);
1874 err:
1875 	if (ca)
1876 		bch2_dev_free(ca);
1877 	bch2_free_super(&sb);
1878 	goto out;
1879 err_late:
1880 	up_write(&c->state_lock);
1881 	ca = NULL;
1882 	goto err;
1883 }
1884 
1885 /* Hot add existing device to running filesystem: */
1886 int bch2_dev_online(struct bch_fs *c, const char *path)
1887 {
1888 	struct bch_opts opts = bch2_opts_empty();
1889 	struct bch_sb_handle sb = { NULL };
1890 	struct bch_dev *ca;
1891 	unsigned dev_idx;
1892 	int ret;
1893 
1894 	down_write(&c->state_lock);
1895 
1896 	ret = bch2_read_super(path, &opts, &sb);
1897 	if (ret) {
1898 		up_write(&c->state_lock);
1899 		return ret;
1900 	}
1901 
1902 	dev_idx = sb.sb->dev_idx;
1903 
1904 	ret = bch2_dev_in_fs(&c->disk_sb, &sb, &c->opts);
1905 	bch_err_msg(c, ret, "bringing %s online", path);
1906 	if (ret)
1907 		goto err;
1908 
1909 	ret = bch2_dev_attach_bdev(c, &sb);
1910 	if (ret)
1911 		goto err;
1912 
1913 	ca = bch2_dev_locked(c, dev_idx);
1914 
1915 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1916 	bch_err_msg(c, ret, "bringing %s online: error from bch2_trans_mark_dev_sb", path);
1917 	if (ret)
1918 		goto err;
1919 
1920 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1921 		__bch2_dev_read_write(c, ca);
1922 
1923 	if (!ca->mi.freespace_initialized) {
1924 		ret = bch2_dev_freespace_init(c, ca, 0, ca->mi.nbuckets);
1925 		bch_err_msg(ca, ret, "initializing free space");
1926 		if (ret)
1927 			goto err;
1928 	}
1929 
1930 	if (!ca->journal.nr) {
1931 		ret = bch2_dev_journal_alloc(ca, false);
1932 		bch_err_msg(ca, ret, "allocating journal");
1933 		if (ret)
1934 			goto err;
1935 	}
1936 
1937 	mutex_lock(&c->sb_lock);
1938 	bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount =
1939 		cpu_to_le64(ktime_get_real_seconds());
1940 	bch2_write_super(c);
1941 	mutex_unlock(&c->sb_lock);
1942 
1943 	up_write(&c->state_lock);
1944 	return 0;
1945 err:
1946 	up_write(&c->state_lock);
1947 	bch2_free_super(&sb);
1948 	return ret;
1949 }
1950 
1951 int bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca, int flags)
1952 {
1953 	down_write(&c->state_lock);
1954 
1955 	if (!bch2_dev_is_online(ca)) {
1956 		bch_err(ca, "Already offline");
1957 		up_write(&c->state_lock);
1958 		return 0;
1959 	}
1960 
1961 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1962 		bch_err(ca, "Cannot offline required disk");
1963 		up_write(&c->state_lock);
1964 		return -BCH_ERR_device_state_not_allowed;
1965 	}
1966 
1967 	__bch2_dev_offline(c, ca);
1968 
1969 	up_write(&c->state_lock);
1970 	return 0;
1971 }
1972 
1973 int bch2_dev_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
1974 {
1975 	struct bch_member *m;
1976 	u64 old_nbuckets;
1977 	int ret = 0;
1978 
1979 	down_write(&c->state_lock);
1980 	old_nbuckets = ca->mi.nbuckets;
1981 
1982 	if (nbuckets < ca->mi.nbuckets) {
1983 		bch_err(ca, "Cannot shrink yet");
1984 		ret = -EINVAL;
1985 		goto err;
1986 	}
1987 
1988 	if (nbuckets > BCH_MEMBER_NBUCKETS_MAX) {
1989 		bch_err(ca, "New device size too big (%llu greater than max %u)",
1990 			nbuckets, BCH_MEMBER_NBUCKETS_MAX);
1991 		ret = -BCH_ERR_device_size_too_big;
1992 		goto err;
1993 	}
1994 
1995 	if (bch2_dev_is_online(ca) &&
1996 	    get_capacity(ca->disk_sb.bdev->bd_disk) <
1997 	    ca->mi.bucket_size * nbuckets) {
1998 		bch_err(ca, "New size larger than device");
1999 		ret = -BCH_ERR_device_size_too_small;
2000 		goto err;
2001 	}
2002 
2003 	ret = bch2_dev_buckets_resize(c, ca, nbuckets);
2004 	bch_err_msg(ca, ret, "resizing buckets");
2005 	if (ret)
2006 		goto err;
2007 
2008 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
2009 	if (ret)
2010 		goto err;
2011 
2012 	mutex_lock(&c->sb_lock);
2013 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
2014 	m->nbuckets = cpu_to_le64(nbuckets);
2015 
2016 	bch2_write_super(c);
2017 	mutex_unlock(&c->sb_lock);
2018 
2019 	if (ca->mi.freespace_initialized) {
2020 		u64 v[3] = { nbuckets - old_nbuckets, 0, 0 };
2021 
2022 		ret   = bch2_trans_commit_do(ca->fs, NULL, NULL, 0,
2023 				bch2_disk_accounting_mod2(trans, false, v, dev_data_type,
2024 							  .dev = ca->dev_idx,
2025 							  .data_type = BCH_DATA_free)) ?:
2026 			bch2_dev_freespace_init(c, ca, old_nbuckets, nbuckets);
2027 		if (ret)
2028 			goto err;
2029 	}
2030 
2031 	bch2_recalc_capacity(c);
2032 err:
2033 	up_write(&c->state_lock);
2034 	return ret;
2035 }
2036 
2037 /* return with ref on ca->ref: */
2038 struct bch_dev *bch2_dev_lookup(struct bch_fs *c, const char *name)
2039 {
2040 	if (!strncmp(name, "/dev/", strlen("/dev/")))
2041 		name += strlen("/dev/");
2042 
2043 	for_each_member_device(c, ca)
2044 		if (!strcmp(name, ca->name))
2045 			return ca;
2046 	return ERR_PTR(-BCH_ERR_ENOENT_dev_not_found);
2047 }
2048 
2049 /* blk_holder_ops: */
2050 
2051 static struct bch_fs *bdev_get_fs(struct block_device *bdev)
2052 	__releases(&bdev->bd_holder_lock)
2053 {
2054 	struct bch_sb_handle_holder *holder = bdev->bd_holder;
2055 	struct bch_fs *c = holder->c;
2056 
2057 	if (c && !bch2_ro_ref_tryget(c))
2058 		c = NULL;
2059 
2060 	mutex_unlock(&bdev->bd_holder_lock);
2061 
2062 	if (c)
2063 		wait_event(c->ro_ref_wait, test_bit(BCH_FS_started, &c->flags));
2064 	return c;
2065 }
2066 
2067 /* returns with ref on ca->ref */
2068 static struct bch_dev *bdev_to_bch_dev(struct bch_fs *c, struct block_device *bdev)
2069 {
2070 	for_each_member_device(c, ca)
2071 		if (ca->disk_sb.bdev == bdev)
2072 			return ca;
2073 	return NULL;
2074 }
2075 
2076 static void bch2_fs_bdev_mark_dead(struct block_device *bdev, bool surprise)
2077 {
2078 	struct bch_fs *c = bdev_get_fs(bdev);
2079 	if (!c)
2080 		return;
2081 
2082 	struct super_block *sb = c->vfs_sb;
2083 	if (sb) {
2084 		/*
2085 		 * Not necessary, c->ro_ref guards against the filesystem being
2086 		 * unmounted - we only take this to avoid a warning in
2087 		 * sync_filesystem:
2088 		 */
2089 		down_read(&sb->s_umount);
2090 	}
2091 
2092 	down_write(&c->state_lock);
2093 	struct bch_dev *ca = bdev_to_bch_dev(c, bdev);
2094 	if (!ca)
2095 		goto unlock;
2096 
2097 	if (bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, BCH_FORCE_IF_DEGRADED)) {
2098 		__bch2_dev_offline(c, ca);
2099 	} else {
2100 		if (sb) {
2101 			if (!surprise)
2102 				sync_filesystem(sb);
2103 			shrink_dcache_sb(sb);
2104 			evict_inodes(sb);
2105 		}
2106 
2107 		bch2_journal_flush(&c->journal);
2108 		bch2_fs_emergency_read_only(c);
2109 	}
2110 
2111 	bch2_dev_put(ca);
2112 unlock:
2113 	if (sb)
2114 		up_read(&sb->s_umount);
2115 	up_write(&c->state_lock);
2116 	bch2_ro_ref_put(c);
2117 }
2118 
2119 static void bch2_fs_bdev_sync(struct block_device *bdev)
2120 {
2121 	struct bch_fs *c = bdev_get_fs(bdev);
2122 	if (!c)
2123 		return;
2124 
2125 	struct super_block *sb = c->vfs_sb;
2126 	if (sb) {
2127 		/*
2128 		 * Not necessary, c->ro_ref guards against the filesystem being
2129 		 * unmounted - we only take this to avoid a warning in
2130 		 * sync_filesystem:
2131 		 */
2132 		down_read(&sb->s_umount);
2133 		sync_filesystem(sb);
2134 		up_read(&sb->s_umount);
2135 	}
2136 
2137 	bch2_ro_ref_put(c);
2138 }
2139 
2140 const struct blk_holder_ops bch2_sb_handle_bdev_ops = {
2141 	.mark_dead		= bch2_fs_bdev_mark_dead,
2142 	.sync			= bch2_fs_bdev_sync,
2143 };
2144 
2145 /* Filesystem open: */
2146 
2147 static inline int sb_cmp(struct bch_sb *l, struct bch_sb *r)
2148 {
2149 	return  cmp_int(le64_to_cpu(l->seq), le64_to_cpu(r->seq)) ?:
2150 		cmp_int(le64_to_cpu(l->write_time), le64_to_cpu(r->write_time));
2151 }
2152 
2153 struct bch_fs *bch2_fs_open(char * const *devices, unsigned nr_devices,
2154 			    struct bch_opts opts)
2155 {
2156 	DARRAY(struct bch_sb_handle) sbs = { 0 };
2157 	struct bch_fs *c = NULL;
2158 	struct bch_sb_handle *best = NULL;
2159 	struct printbuf errbuf = PRINTBUF;
2160 	int ret = 0;
2161 
2162 	if (!try_module_get(THIS_MODULE))
2163 		return ERR_PTR(-ENODEV);
2164 
2165 	if (!nr_devices) {
2166 		ret = -EINVAL;
2167 		goto err;
2168 	}
2169 
2170 	ret = darray_make_room(&sbs, nr_devices);
2171 	if (ret)
2172 		goto err;
2173 
2174 	for (unsigned i = 0; i < nr_devices; i++) {
2175 		struct bch_sb_handle sb = { NULL };
2176 
2177 		ret = bch2_read_super(devices[i], &opts, &sb);
2178 		if (ret)
2179 			goto err;
2180 
2181 		BUG_ON(darray_push(&sbs, sb));
2182 	}
2183 
2184 	if (opts.nochanges && !opts.read_only) {
2185 		ret = -BCH_ERR_erofs_nochanges;
2186 		goto err_print;
2187 	}
2188 
2189 	darray_for_each(sbs, sb)
2190 		if (!best || sb_cmp(sb->sb, best->sb) > 0)
2191 			best = sb;
2192 
2193 	darray_for_each_reverse(sbs, sb) {
2194 		ret = bch2_dev_in_fs(best, sb, &opts);
2195 
2196 		if (ret == -BCH_ERR_device_has_been_removed ||
2197 		    ret == -BCH_ERR_device_splitbrain) {
2198 			bch2_free_super(sb);
2199 			darray_remove_item(&sbs, sb);
2200 			best -= best > sb;
2201 			ret = 0;
2202 			continue;
2203 		}
2204 
2205 		if (ret)
2206 			goto err_print;
2207 	}
2208 
2209 	c = bch2_fs_alloc(best->sb, opts);
2210 	ret = PTR_ERR_OR_ZERO(c);
2211 	if (ret)
2212 		goto err;
2213 
2214 	down_write(&c->state_lock);
2215 	darray_for_each(sbs, sb) {
2216 		ret = bch2_dev_attach_bdev(c, sb);
2217 		if (ret) {
2218 			up_write(&c->state_lock);
2219 			goto err;
2220 		}
2221 	}
2222 	up_write(&c->state_lock);
2223 
2224 	if (!bch2_fs_may_start(c)) {
2225 		ret = -BCH_ERR_insufficient_devices_to_start;
2226 		goto err_print;
2227 	}
2228 
2229 	if (!c->opts.nostart) {
2230 		ret = bch2_fs_start(c);
2231 		if (ret)
2232 			goto err;
2233 	}
2234 out:
2235 	darray_for_each(sbs, sb)
2236 		bch2_free_super(sb);
2237 	darray_exit(&sbs);
2238 	printbuf_exit(&errbuf);
2239 	module_put(THIS_MODULE);
2240 	return c;
2241 err_print:
2242 	pr_err("bch_fs_open err opening %s: %s",
2243 	       devices[0], bch2_err_str(ret));
2244 err:
2245 	if (!IS_ERR_OR_NULL(c))
2246 		bch2_fs_stop(c);
2247 	c = ERR_PTR(ret);
2248 	goto out;
2249 }
2250 
2251 /* Global interfaces/init */
2252 
2253 static void bcachefs_exit(void)
2254 {
2255 	bch2_debug_exit();
2256 	bch2_vfs_exit();
2257 	bch2_chardev_exit();
2258 	bch2_btree_key_cache_exit();
2259 	if (bcachefs_kset)
2260 		kset_unregister(bcachefs_kset);
2261 }
2262 
2263 static int __init bcachefs_init(void)
2264 {
2265 	bch2_bkey_pack_test();
2266 
2267 	if (!(bcachefs_kset = kset_create_and_add("bcachefs", NULL, fs_kobj)) ||
2268 	    bch2_btree_key_cache_init() ||
2269 	    bch2_chardev_init() ||
2270 	    bch2_vfs_init() ||
2271 	    bch2_debug_init())
2272 		goto err;
2273 
2274 	return 0;
2275 err:
2276 	bcachefs_exit();
2277 	return -ENOMEM;
2278 }
2279 
2280 #define BCH_DEBUG_PARAM(name, description)			\
2281 	bool bch2_##name;					\
2282 	module_param_named(name, bch2_##name, bool, 0644);	\
2283 	MODULE_PARM_DESC(name, description);
2284 BCH_DEBUG_PARAMS()
2285 #undef BCH_DEBUG_PARAM
2286 
2287 __maybe_unused
2288 static unsigned bch2_metadata_version = bcachefs_metadata_version_current;
2289 module_param_named(version, bch2_metadata_version, uint, 0444);
2290 
2291 module_exit(bcachefs_exit);
2292 module_init(bcachefs_init);
2293