xref: /linux/fs/bcachefs/super.c (revision ff388fe5c481d39cc0a5940d1ad46f7920f1d646)
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_groups.h"
29 #include "ec.h"
30 #include "errcode.h"
31 #include "error.h"
32 #include "fs.h"
33 #include "fs-io.h"
34 #include "fs-io-buffered.h"
35 #include "fs-io-direct.h"
36 #include "fsck.h"
37 #include "inode.h"
38 #include "io_read.h"
39 #include "io_write.h"
40 #include "journal.h"
41 #include "journal_reclaim.h"
42 #include "journal_seq_blacklist.h"
43 #include "move.h"
44 #include "migrate.h"
45 #include "movinggc.h"
46 #include "nocow_locking.h"
47 #include "quota.h"
48 #include "rebalance.h"
49 #include "recovery.h"
50 #include "replicas.h"
51 #include "sb-clean.h"
52 #include "sb-counters.h"
53 #include "sb-errors.h"
54 #include "sb-members.h"
55 #include "snapshot.h"
56 #include "subvolume.h"
57 #include "super.h"
58 #include "super-io.h"
59 #include "sysfs.h"
60 #include "thread_with_file.h"
61 #include "trace.h"
62 
63 #include <linux/backing-dev.h>
64 #include <linux/blkdev.h>
65 #include <linux/debugfs.h>
66 #include <linux/device.h>
67 #include <linux/idr.h>
68 #include <linux/module.h>
69 #include <linux/percpu.h>
70 #include <linux/random.h>
71 #include <linux/sysfs.h>
72 #include <crypto/hash.h>
73 
74 MODULE_LICENSE("GPL");
75 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
76 MODULE_DESCRIPTION("bcachefs filesystem");
77 MODULE_SOFTDEP("pre: crc32c");
78 MODULE_SOFTDEP("pre: crc64");
79 MODULE_SOFTDEP("pre: sha256");
80 MODULE_SOFTDEP("pre: chacha20");
81 MODULE_SOFTDEP("pre: poly1305");
82 MODULE_SOFTDEP("pre: xxhash");
83 
84 const char * const bch2_fs_flag_strs[] = {
85 #define x(n)		#n,
86 	BCH_FS_FLAGS()
87 #undef x
88 	NULL
89 };
90 
91 __printf(2, 0)
92 static void bch2_print_maybe_redirect(struct stdio_redirect *stdio, const char *fmt, va_list args)
93 {
94 #ifdef __KERNEL__
95 	if (unlikely(stdio)) {
96 		if (fmt[0] == KERN_SOH[0])
97 			fmt += 2;
98 
99 		bch2_stdio_redirect_vprintf(stdio, true, fmt, args);
100 		return;
101 	}
102 #endif
103 	vprintk(fmt, args);
104 }
105 
106 void bch2_print_opts(struct bch_opts *opts, const char *fmt, ...)
107 {
108 	struct stdio_redirect *stdio = (void *)(unsigned long)opts->stdio;
109 
110 	va_list args;
111 	va_start(args, fmt);
112 	bch2_print_maybe_redirect(stdio, fmt, args);
113 	va_end(args);
114 }
115 
116 void __bch2_print(struct bch_fs *c, const char *fmt, ...)
117 {
118 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
119 
120 	va_list args;
121 	va_start(args, fmt);
122 	bch2_print_maybe_redirect(stdio, fmt, args);
123 	va_end(args);
124 }
125 
126 #define KTYPE(type)							\
127 static const struct attribute_group type ## _group = {			\
128 	.attrs = type ## _files						\
129 };									\
130 									\
131 static const struct attribute_group *type ## _groups[] = {		\
132 	&type ## _group,						\
133 	NULL								\
134 };									\
135 									\
136 static const struct kobj_type type ## _ktype = {			\
137 	.release	= type ## _release,				\
138 	.sysfs_ops	= &type ## _sysfs_ops,				\
139 	.default_groups = type ## _groups				\
140 }
141 
142 static void bch2_fs_release(struct kobject *);
143 static void bch2_dev_release(struct kobject *);
144 static void bch2_fs_counters_release(struct kobject *k)
145 {
146 }
147 
148 static void bch2_fs_internal_release(struct kobject *k)
149 {
150 }
151 
152 static void bch2_fs_opts_dir_release(struct kobject *k)
153 {
154 }
155 
156 static void bch2_fs_time_stats_release(struct kobject *k)
157 {
158 }
159 
160 KTYPE(bch2_fs);
161 KTYPE(bch2_fs_counters);
162 KTYPE(bch2_fs_internal);
163 KTYPE(bch2_fs_opts_dir);
164 KTYPE(bch2_fs_time_stats);
165 KTYPE(bch2_dev);
166 
167 static struct kset *bcachefs_kset;
168 static LIST_HEAD(bch_fs_list);
169 static DEFINE_MUTEX(bch_fs_list_lock);
170 
171 DECLARE_WAIT_QUEUE_HEAD(bch2_read_only_wait);
172 
173 static void bch2_dev_free(struct bch_dev *);
174 static int bch2_dev_alloc(struct bch_fs *, unsigned);
175 static int bch2_dev_sysfs_online(struct bch_fs *, struct bch_dev *);
176 static void __bch2_dev_read_only(struct bch_fs *, struct bch_dev *);
177 
178 struct bch_fs *bch2_dev_to_fs(dev_t dev)
179 {
180 	struct bch_fs *c;
181 
182 	mutex_lock(&bch_fs_list_lock);
183 	rcu_read_lock();
184 
185 	list_for_each_entry(c, &bch_fs_list, list)
186 		for_each_member_device_rcu(c, ca, NULL)
187 			if (ca->disk_sb.bdev && ca->disk_sb.bdev->bd_dev == dev) {
188 				closure_get(&c->cl);
189 				goto found;
190 			}
191 	c = NULL;
192 found:
193 	rcu_read_unlock();
194 	mutex_unlock(&bch_fs_list_lock);
195 
196 	return c;
197 }
198 
199 static struct bch_fs *__bch2_uuid_to_fs(__uuid_t uuid)
200 {
201 	struct bch_fs *c;
202 
203 	lockdep_assert_held(&bch_fs_list_lock);
204 
205 	list_for_each_entry(c, &bch_fs_list, list)
206 		if (!memcmp(&c->disk_sb.sb->uuid, &uuid, sizeof(uuid)))
207 			return c;
208 
209 	return NULL;
210 }
211 
212 struct bch_fs *bch2_uuid_to_fs(__uuid_t uuid)
213 {
214 	struct bch_fs *c;
215 
216 	mutex_lock(&bch_fs_list_lock);
217 	c = __bch2_uuid_to_fs(uuid);
218 	if (c)
219 		closure_get(&c->cl);
220 	mutex_unlock(&bch_fs_list_lock);
221 
222 	return c;
223 }
224 
225 static void bch2_dev_usage_journal_reserve(struct bch_fs *c)
226 {
227 	unsigned nr = 0, u64s =
228 		((sizeof(struct jset_entry_dev_usage) +
229 		  sizeof(struct jset_entry_dev_usage_type) * BCH_DATA_NR)) /
230 		sizeof(u64);
231 
232 	rcu_read_lock();
233 	for_each_member_device_rcu(c, ca, NULL)
234 		nr++;
235 	rcu_read_unlock();
236 
237 	bch2_journal_entry_res_resize(&c->journal,
238 			&c->dev_usage_journal_res, u64s * nr);
239 }
240 
241 /* Filesystem RO/RW: */
242 
243 /*
244  * For startup/shutdown of RW stuff, the dependencies are:
245  *
246  * - foreground writes depend on copygc and rebalance (to free up space)
247  *
248  * - copygc and rebalance depend on mark and sweep gc (they actually probably
249  *   don't because they either reserve ahead of time or don't block if
250  *   allocations fail, but allocations can require mark and sweep gc to run
251  *   because of generation number wraparound)
252  *
253  * - all of the above depends on the allocator threads
254  *
255  * - allocator depends on the journal (when it rewrites prios and gens)
256  */
257 
258 static void __bch2_fs_read_only(struct bch_fs *c)
259 {
260 	unsigned clean_passes = 0;
261 	u64 seq = 0;
262 
263 	bch2_fs_ec_stop(c);
264 	bch2_open_buckets_stop(c, NULL, true);
265 	bch2_rebalance_stop(c);
266 	bch2_copygc_stop(c);
267 	bch2_fs_ec_flush(c);
268 
269 	bch_verbose(c, "flushing journal and stopping allocators, journal seq %llu",
270 		    journal_cur_seq(&c->journal));
271 
272 	do {
273 		clean_passes++;
274 
275 		if (bch2_btree_interior_updates_flush(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, "%sshutdown 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_read(&c->btree_cache.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 
380 		bch_verbose(c, "marking filesystem clean");
381 		bch2_fs_mark_clean(c);
382 	} else {
383 		bch_verbose(c, "done going read-only, filesystem not clean");
384 	}
385 }
386 
387 static void bch2_fs_read_only_work(struct work_struct *work)
388 {
389 	struct bch_fs *c =
390 		container_of(work, struct bch_fs, read_only_work);
391 
392 	down_write(&c->state_lock);
393 	bch2_fs_read_only(c);
394 	up_write(&c->state_lock);
395 }
396 
397 static void bch2_fs_read_only_async(struct bch_fs *c)
398 {
399 	queue_work(system_long_wq, &c->read_only_work);
400 }
401 
402 bool bch2_fs_emergency_read_only(struct bch_fs *c)
403 {
404 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
405 
406 	bch2_journal_halt(&c->journal);
407 	bch2_fs_read_only_async(c);
408 
409 	wake_up(&bch2_read_only_wait);
410 	return ret;
411 }
412 
413 static int bch2_fs_read_write_late(struct bch_fs *c)
414 {
415 	int ret;
416 
417 	/*
418 	 * Data move operations can't run until after check_snapshots has
419 	 * completed, and bch2_snapshot_is_ancestor() is available.
420 	 *
421 	 * Ideally we'd start copygc/rebalance earlier instead of waiting for
422 	 * all of recovery/fsck to complete:
423 	 */
424 	ret = bch2_copygc_start(c);
425 	if (ret) {
426 		bch_err(c, "error starting copygc thread");
427 		return ret;
428 	}
429 
430 	ret = bch2_rebalance_start(c);
431 	if (ret) {
432 		bch_err(c, "error starting rebalance thread");
433 		return ret;
434 	}
435 
436 	return 0;
437 }
438 
439 static int __bch2_fs_read_write(struct bch_fs *c, bool early)
440 {
441 	int ret;
442 
443 	if (test_bit(BCH_FS_initial_gc_unfixed, &c->flags)) {
444 		bch_err(c, "cannot go rw, unfixed btree errors");
445 		return -BCH_ERR_erofs_unfixed_errors;
446 	}
447 
448 	if (test_bit(BCH_FS_rw, &c->flags))
449 		return 0;
450 
451 	bch_info(c, "going read-write");
452 
453 	ret = bch2_sb_members_v2_init(c);
454 	if (ret)
455 		goto err;
456 
457 	ret = bch2_fs_mark_dirty(c);
458 	if (ret)
459 		goto err;
460 
461 	clear_bit(BCH_FS_clean_shutdown, &c->flags);
462 
463 	/*
464 	 * First journal write must be a flush write: after a clean shutdown we
465 	 * don't read the journal, so the first journal write may end up
466 	 * overwriting whatever was there previously, and there must always be
467 	 * at least one non-flush write in the journal or recovery will fail:
468 	 */
469 	set_bit(JOURNAL_need_flush_write, &c->journal.flags);
470 	set_bit(JOURNAL_running, &c->journal.flags);
471 
472 	for_each_rw_member(c, ca)
473 		bch2_dev_allocator_add(c, ca);
474 	bch2_recalc_capacity(c);
475 
476 	set_bit(BCH_FS_rw, &c->flags);
477 	set_bit(BCH_FS_was_rw, &c->flags);
478 
479 #ifndef BCH_WRITE_REF_DEBUG
480 	percpu_ref_reinit(&c->writes);
481 #else
482 	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++) {
483 		BUG_ON(atomic_long_read(&c->writes[i]));
484 		atomic_long_inc(&c->writes[i]);
485 	}
486 #endif
487 
488 	ret = bch2_journal_reclaim_start(&c->journal);
489 	if (ret)
490 		goto err;
491 
492 	if (!early) {
493 		ret = bch2_fs_read_write_late(c);
494 		if (ret)
495 			goto err;
496 	}
497 
498 	bch2_do_discards(c);
499 	bch2_do_invalidates(c);
500 	bch2_do_stripe_deletes(c);
501 	bch2_do_pending_node_rewrites(c);
502 	return 0;
503 err:
504 	if (test_bit(BCH_FS_rw, &c->flags))
505 		bch2_fs_read_only(c);
506 	else
507 		__bch2_fs_read_only(c);
508 	return ret;
509 }
510 
511 int bch2_fs_read_write(struct bch_fs *c)
512 {
513 	if (c->opts.recovery_pass_last &&
514 	    c->opts.recovery_pass_last < BCH_RECOVERY_PASS_journal_replay)
515 		return -BCH_ERR_erofs_norecovery;
516 
517 	if (c->opts.nochanges)
518 		return -BCH_ERR_erofs_nochanges;
519 
520 	return __bch2_fs_read_write(c, false);
521 }
522 
523 int bch2_fs_read_write_early(struct bch_fs *c)
524 {
525 	lockdep_assert_held(&c->state_lock);
526 
527 	return __bch2_fs_read_write(c, true);
528 }
529 
530 /* Filesystem startup/shutdown: */
531 
532 static void __bch2_fs_free(struct bch_fs *c)
533 {
534 	for (unsigned i = 0; i < BCH_TIME_STAT_NR; i++)
535 		bch2_time_stats_exit(&c->times[i]);
536 
537 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
538 	bch2_free_pending_node_rewrites(c);
539 	bch2_fs_allocator_background_exit(c);
540 	bch2_fs_sb_errors_exit(c);
541 	bch2_fs_counters_exit(c);
542 	bch2_fs_snapshots_exit(c);
543 	bch2_fs_quota_exit(c);
544 	bch2_fs_fs_io_direct_exit(c);
545 	bch2_fs_fs_io_buffered_exit(c);
546 	bch2_fs_fsio_exit(c);
547 	bch2_fs_ec_exit(c);
548 	bch2_fs_encryption_exit(c);
549 	bch2_fs_nocow_locking_exit(c);
550 	bch2_fs_io_write_exit(c);
551 	bch2_fs_io_read_exit(c);
552 	bch2_fs_buckets_waiting_for_journal_exit(c);
553 	bch2_fs_btree_interior_update_exit(c);
554 	bch2_fs_btree_iter_exit(c);
555 	bch2_fs_btree_key_cache_exit(&c->btree_key_cache);
556 	bch2_fs_btree_cache_exit(c);
557 	bch2_fs_replicas_exit(c);
558 	bch2_fs_journal_exit(&c->journal);
559 	bch2_io_clock_exit(&c->io_clock[WRITE]);
560 	bch2_io_clock_exit(&c->io_clock[READ]);
561 	bch2_fs_compress_exit(c);
562 	bch2_journal_keys_put_initial(c);
563 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
564 	BUG_ON(atomic_read(&c->journal_keys.ref));
565 	bch2_fs_btree_write_buffer_exit(c);
566 	percpu_free_rwsem(&c->mark_lock);
567 	EBUG_ON(percpu_u64_get(c->online_reserved));
568 	free_percpu(c->online_reserved);
569 
570 	darray_exit(&c->btree_roots_extra);
571 	free_percpu(c->pcpu);
572 	mempool_exit(&c->large_bkey_pool);
573 	mempool_exit(&c->btree_bounce_pool);
574 	bioset_exit(&c->btree_bio);
575 	mempool_exit(&c->fill_iter);
576 #ifndef BCH_WRITE_REF_DEBUG
577 	percpu_ref_exit(&c->writes);
578 #endif
579 	kfree(rcu_dereference_protected(c->disk_groups, 1));
580 	kfree(c->journal_seq_blacklist_table);
581 	kfree(c->unused_inode_hints);
582 
583 	if (c->write_ref_wq)
584 		destroy_workqueue(c->write_ref_wq);
585 	if (c->io_complete_wq)
586 		destroy_workqueue(c->io_complete_wq);
587 	if (c->copygc_wq)
588 		destroy_workqueue(c->copygc_wq);
589 	if (c->btree_io_complete_wq)
590 		destroy_workqueue(c->btree_io_complete_wq);
591 	if (c->btree_update_wq)
592 		destroy_workqueue(c->btree_update_wq);
593 
594 	bch2_free_super(&c->disk_sb);
595 	kvfree(c);
596 	module_put(THIS_MODULE);
597 }
598 
599 static void bch2_fs_release(struct kobject *kobj)
600 {
601 	struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
602 
603 	__bch2_fs_free(c);
604 }
605 
606 void __bch2_fs_stop(struct bch_fs *c)
607 {
608 	bch_verbose(c, "shutting down");
609 
610 	set_bit(BCH_FS_stopping, &c->flags);
611 
612 	down_write(&c->state_lock);
613 	bch2_fs_read_only(c);
614 	up_write(&c->state_lock);
615 
616 	for_each_member_device(c, ca)
617 		if (ca->kobj.state_in_sysfs &&
618 		    ca->disk_sb.bdev)
619 			sysfs_remove_link(bdev_kobj(ca->disk_sb.bdev), "bcachefs");
620 
621 	if (c->kobj.state_in_sysfs)
622 		kobject_del(&c->kobj);
623 
624 	bch2_fs_debug_exit(c);
625 	bch2_fs_chardev_exit(c);
626 
627 	bch2_ro_ref_put(c);
628 	wait_event(c->ro_ref_wait, !refcount_read(&c->ro_ref));
629 
630 	kobject_put(&c->counters_kobj);
631 	kobject_put(&c->time_stats);
632 	kobject_put(&c->opts_dir);
633 	kobject_put(&c->internal);
634 
635 	/* btree prefetch might have kicked off reads in the background: */
636 	bch2_btree_flush_all_reads(c);
637 
638 	for_each_member_device(c, ca)
639 		cancel_work_sync(&ca->io_error_work);
640 
641 	cancel_work_sync(&c->read_only_work);
642 }
643 
644 void bch2_fs_free(struct bch_fs *c)
645 {
646 	unsigned i;
647 
648 	mutex_lock(&bch_fs_list_lock);
649 	list_del(&c->list);
650 	mutex_unlock(&bch_fs_list_lock);
651 
652 	closure_sync(&c->cl);
653 	closure_debug_destroy(&c->cl);
654 
655 	for (i = 0; i < c->sb.nr_devices; i++) {
656 		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
657 
658 		if (ca) {
659 			EBUG_ON(atomic_long_read(&ca->ref) != 1);
660 			bch2_free_super(&ca->disk_sb);
661 			bch2_dev_free(ca);
662 		}
663 	}
664 
665 	bch_verbose(c, "shutdown complete");
666 
667 	kobject_put(&c->kobj);
668 }
669 
670 void bch2_fs_stop(struct bch_fs *c)
671 {
672 	__bch2_fs_stop(c);
673 	bch2_fs_free(c);
674 }
675 
676 static int bch2_fs_online(struct bch_fs *c)
677 {
678 	int ret = 0;
679 
680 	lockdep_assert_held(&bch_fs_list_lock);
681 
682 	if (__bch2_uuid_to_fs(c->sb.uuid)) {
683 		bch_err(c, "filesystem UUID already open");
684 		return -EINVAL;
685 	}
686 
687 	ret = bch2_fs_chardev_init(c);
688 	if (ret) {
689 		bch_err(c, "error creating character device");
690 		return ret;
691 	}
692 
693 	bch2_fs_debug_init(c);
694 
695 	ret = kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b) ?:
696 	    kobject_add(&c->internal, &c->kobj, "internal") ?:
697 	    kobject_add(&c->opts_dir, &c->kobj, "options") ?:
698 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
699 	    kobject_add(&c->time_stats, &c->kobj, "time_stats") ?:
700 #endif
701 	    kobject_add(&c->counters_kobj, &c->kobj, "counters") ?:
702 	    bch2_opts_create_sysfs_files(&c->opts_dir);
703 	if (ret) {
704 		bch_err(c, "error creating sysfs objects");
705 		return ret;
706 	}
707 
708 	down_write(&c->state_lock);
709 
710 	for_each_member_device(c, ca) {
711 		ret = bch2_dev_sysfs_online(c, ca);
712 		if (ret) {
713 			bch_err(c, "error creating sysfs objects");
714 			bch2_dev_put(ca);
715 			goto err;
716 		}
717 	}
718 
719 	BUG_ON(!list_empty(&c->list));
720 	list_add(&c->list, &bch_fs_list);
721 err:
722 	up_write(&c->state_lock);
723 	return ret;
724 }
725 
726 static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
727 {
728 	struct bch_fs *c;
729 	struct printbuf name = PRINTBUF;
730 	unsigned i, iter_size;
731 	int ret = 0;
732 
733 	c = kvmalloc(sizeof(struct bch_fs), GFP_KERNEL|__GFP_ZERO);
734 	if (!c) {
735 		c = ERR_PTR(-BCH_ERR_ENOMEM_fs_alloc);
736 		goto out;
737 	}
738 
739 	c->stdio = (void *)(unsigned long) opts.stdio;
740 
741 	__module_get(THIS_MODULE);
742 
743 	closure_init(&c->cl, NULL);
744 
745 	c->kobj.kset = bcachefs_kset;
746 	kobject_init(&c->kobj, &bch2_fs_ktype);
747 	kobject_init(&c->internal, &bch2_fs_internal_ktype);
748 	kobject_init(&c->opts_dir, &bch2_fs_opts_dir_ktype);
749 	kobject_init(&c->time_stats, &bch2_fs_time_stats_ktype);
750 	kobject_init(&c->counters_kobj, &bch2_fs_counters_ktype);
751 
752 	c->minor		= -1;
753 	c->disk_sb.fs_sb	= true;
754 
755 	init_rwsem(&c->state_lock);
756 	mutex_init(&c->sb_lock);
757 	mutex_init(&c->replicas_gc_lock);
758 	mutex_init(&c->btree_root_lock);
759 	INIT_WORK(&c->read_only_work, bch2_fs_read_only_work);
760 
761 	refcount_set(&c->ro_ref, 1);
762 	init_waitqueue_head(&c->ro_ref_wait);
763 	sema_init(&c->online_fsck_mutex, 1);
764 
765 	init_rwsem(&c->gc_lock);
766 	mutex_init(&c->gc_gens_lock);
767 	atomic_set(&c->journal_keys.ref, 1);
768 	c->journal_keys.initial_ref_held = true;
769 
770 	for (i = 0; i < BCH_TIME_STAT_NR; i++)
771 		bch2_time_stats_init(&c->times[i]);
772 
773 	bch2_fs_gc_init(c);
774 	bch2_fs_copygc_init(c);
775 	bch2_fs_btree_key_cache_init_early(&c->btree_key_cache);
776 	bch2_fs_btree_iter_init_early(c);
777 	bch2_fs_btree_interior_update_init_early(c);
778 	bch2_fs_allocator_background_init(c);
779 	bch2_fs_allocator_foreground_init(c);
780 	bch2_fs_rebalance_init(c);
781 	bch2_fs_quota_init(c);
782 	bch2_fs_ec_init_early(c);
783 	bch2_fs_move_init(c);
784 	bch2_fs_sb_errors_init_early(c);
785 
786 	INIT_LIST_HEAD(&c->list);
787 
788 	mutex_init(&c->usage_scratch_lock);
789 
790 	mutex_init(&c->bio_bounce_pages_lock);
791 	mutex_init(&c->snapshot_table_lock);
792 	init_rwsem(&c->snapshot_create_lock);
793 
794 	spin_lock_init(&c->btree_write_error_lock);
795 
796 	INIT_LIST_HEAD(&c->journal_iters);
797 
798 	INIT_LIST_HEAD(&c->fsck_error_msgs);
799 	mutex_init(&c->fsck_error_msgs_lock);
800 
801 	seqcount_init(&c->usage_lock);
802 
803 	sema_init(&c->io_in_flight, 128);
804 
805 	INIT_LIST_HEAD(&c->vfs_inodes_list);
806 	mutex_init(&c->vfs_inodes_lock);
807 
808 	c->copy_gc_enabled		= 1;
809 	c->rebalance.enabled		= 1;
810 	c->promote_whole_extents	= true;
811 
812 	c->journal.flush_write_time	= &c->times[BCH_TIME_journal_flush_write];
813 	c->journal.noflush_write_time	= &c->times[BCH_TIME_journal_noflush_write];
814 	c->journal.flush_seq_time	= &c->times[BCH_TIME_journal_flush_seq];
815 
816 	bch2_fs_btree_cache_init_early(&c->btree_cache);
817 
818 	mutex_init(&c->sectors_available_lock);
819 
820 	ret = percpu_init_rwsem(&c->mark_lock);
821 	if (ret)
822 		goto err;
823 
824 	mutex_lock(&c->sb_lock);
825 	ret = bch2_sb_to_fs(c, sb);
826 	mutex_unlock(&c->sb_lock);
827 
828 	if (ret)
829 		goto err;
830 
831 	pr_uuid(&name, c->sb.user_uuid.b);
832 	ret = name.allocation_failure ? -BCH_ERR_ENOMEM_fs_name_alloc : 0;
833 	if (ret)
834 		goto err;
835 
836 	strscpy(c->name, name.buf, sizeof(c->name));
837 	printbuf_exit(&name);
838 
839 	/* Compat: */
840 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
841 	    !BCH_SB_JOURNAL_FLUSH_DELAY(sb))
842 		SET_BCH_SB_JOURNAL_FLUSH_DELAY(sb, 1000);
843 
844 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
845 	    !BCH_SB_JOURNAL_RECLAIM_DELAY(sb))
846 		SET_BCH_SB_JOURNAL_RECLAIM_DELAY(sb, 100);
847 
848 	c->opts = bch2_opts_default;
849 	ret = bch2_opts_from_sb(&c->opts, sb);
850 	if (ret)
851 		goto err;
852 
853 	bch2_opts_apply(&c->opts, opts);
854 
855 	c->btree_key_cache_btrees |= 1U << BTREE_ID_alloc;
856 	if (c->opts.inodes_use_key_cache)
857 		c->btree_key_cache_btrees |= 1U << BTREE_ID_inodes;
858 	c->btree_key_cache_btrees |= 1U << BTREE_ID_logged_ops;
859 
860 	c->block_bits		= ilog2(block_sectors(c));
861 	c->btree_foreground_merge_threshold = BTREE_FOREGROUND_MERGE_THRESHOLD(c);
862 
863 	if (bch2_fs_init_fault("fs_alloc")) {
864 		bch_err(c, "fs_alloc fault injected");
865 		ret = -EFAULT;
866 		goto err;
867 	}
868 
869 	iter_size = sizeof(struct sort_iter) +
870 		(btree_blocks(c) + 1) * 2 *
871 		sizeof(struct sort_iter_set);
872 
873 	c->inode_shard_bits = ilog2(roundup_pow_of_two(num_possible_cpus()));
874 
875 	if (!(c->btree_update_wq = alloc_workqueue("bcachefs",
876 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_UNBOUND, 512)) ||
877 	    !(c->btree_io_complete_wq = alloc_workqueue("bcachefs_btree_io",
878 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
879 	    !(c->copygc_wq = alloc_workqueue("bcachefs_copygc",
880 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 1)) ||
881 	    !(c->io_complete_wq = alloc_workqueue("bcachefs_io",
882 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 512)) ||
883 	    !(c->write_ref_wq = alloc_workqueue("bcachefs_write_ref",
884 				WQ_FREEZABLE, 0)) ||
885 #ifndef BCH_WRITE_REF_DEBUG
886 	    percpu_ref_init(&c->writes, bch2_writes_disabled,
887 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
888 #endif
889 	    mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
890 	    bioset_init(&c->btree_bio, 1,
891 			max(offsetof(struct btree_read_bio, bio),
892 			    offsetof(struct btree_write_bio, wbio.bio)),
893 			BIOSET_NEED_BVECS) ||
894 	    !(c->pcpu = alloc_percpu(struct bch_fs_pcpu)) ||
895 	    !(c->online_reserved = alloc_percpu(u64)) ||
896 	    mempool_init_kvmalloc_pool(&c->btree_bounce_pool, 1,
897 				       c->opts.btree_node_size) ||
898 	    mempool_init_kmalloc_pool(&c->large_bkey_pool, 1, 2048) ||
899 	    !(c->unused_inode_hints = kcalloc(1U << c->inode_shard_bits,
900 					      sizeof(u64), GFP_KERNEL))) {
901 		ret = -BCH_ERR_ENOMEM_fs_other_alloc;
902 		goto err;
903 	}
904 
905 	ret = bch2_fs_counters_init(c) ?:
906 	    bch2_fs_sb_errors_init(c) ?:
907 	    bch2_io_clock_init(&c->io_clock[READ]) ?:
908 	    bch2_io_clock_init(&c->io_clock[WRITE]) ?:
909 	    bch2_fs_journal_init(&c->journal) ?:
910 	    bch2_fs_replicas_init(c) ?:
911 	    bch2_fs_btree_cache_init(c) ?:
912 	    bch2_fs_btree_key_cache_init(&c->btree_key_cache) ?:
913 	    bch2_fs_btree_iter_init(c) ?:
914 	    bch2_fs_btree_interior_update_init(c) ?:
915 	    bch2_fs_buckets_waiting_for_journal_init(c) ?:
916 	    bch2_fs_btree_write_buffer_init(c) ?:
917 	    bch2_fs_subvolumes_init(c) ?:
918 	    bch2_fs_io_read_init(c) ?:
919 	    bch2_fs_io_write_init(c) ?:
920 	    bch2_fs_nocow_locking_init(c) ?:
921 	    bch2_fs_encryption_init(c) ?:
922 	    bch2_fs_compress_init(c) ?:
923 	    bch2_fs_ec_init(c) ?:
924 	    bch2_fs_fsio_init(c) ?:
925 	    bch2_fs_fs_io_buffered_init(c) ?:
926 	    bch2_fs_fs_io_direct_init(c);
927 	if (ret)
928 		goto err;
929 
930 	for (i = 0; i < c->sb.nr_devices; i++)
931 		if (bch2_member_exists(c->disk_sb.sb, i) &&
932 		    bch2_dev_alloc(c, i)) {
933 			ret = -EEXIST;
934 			goto err;
935 		}
936 
937 	bch2_journal_entry_res_resize(&c->journal,
938 			&c->btree_root_journal_res,
939 			BTREE_ID_NR * (JSET_KEYS_U64s + BKEY_BTREE_PTR_U64s_MAX));
940 	bch2_dev_usage_journal_reserve(c);
941 	bch2_journal_entry_res_resize(&c->journal,
942 			&c->clock_journal_res,
943 			(sizeof(struct jset_entry_clock) / sizeof(u64)) * 2);
944 
945 	mutex_lock(&bch_fs_list_lock);
946 	ret = bch2_fs_online(c);
947 	mutex_unlock(&bch_fs_list_lock);
948 
949 	if (ret)
950 		goto err;
951 out:
952 	return c;
953 err:
954 	bch2_fs_free(c);
955 	c = ERR_PTR(ret);
956 	goto out;
957 }
958 
959 noinline_for_stack
960 static void print_mount_opts(struct bch_fs *c)
961 {
962 	enum bch_opt_id i;
963 	struct printbuf p = PRINTBUF;
964 	bool first = true;
965 
966 	prt_str(&p, "mounting version ");
967 	bch2_version_to_text(&p, c->sb.version);
968 
969 	if (c->opts.read_only) {
970 		prt_str(&p, " opts=");
971 		first = false;
972 		prt_printf(&p, "ro");
973 	}
974 
975 	for (i = 0; i < bch2_opts_nr; i++) {
976 		const struct bch_option *opt = &bch2_opt_table[i];
977 		u64 v = bch2_opt_get_by_id(&c->opts, i);
978 
979 		if (!(opt->flags & OPT_MOUNT))
980 			continue;
981 
982 		if (v == bch2_opt_get_by_id(&bch2_opts_default, i))
983 			continue;
984 
985 		prt_str(&p, first ? " opts=" : ",");
986 		first = false;
987 		bch2_opt_to_text(&p, c, c->disk_sb.sb, opt, v, OPT_SHOW_MOUNT_STYLE);
988 	}
989 
990 	bch_info(c, "%s", p.buf);
991 	printbuf_exit(&p);
992 }
993 
994 int bch2_fs_start(struct bch_fs *c)
995 {
996 	time64_t now = ktime_get_real_seconds();
997 	int ret;
998 
999 	print_mount_opts(c);
1000 
1001 	down_write(&c->state_lock);
1002 
1003 	BUG_ON(test_bit(BCH_FS_started, &c->flags));
1004 
1005 	mutex_lock(&c->sb_lock);
1006 
1007 	ret = bch2_sb_members_v2_init(c);
1008 	if (ret) {
1009 		mutex_unlock(&c->sb_lock);
1010 		goto err;
1011 	}
1012 
1013 	for_each_online_member(c, ca)
1014 		bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount = cpu_to_le64(now);
1015 
1016 	struct bch_sb_field_ext *ext =
1017 		bch2_sb_field_get_minsize(&c->disk_sb, ext, sizeof(*ext) / sizeof(u64));
1018 	mutex_unlock(&c->sb_lock);
1019 
1020 	if (!ext) {
1021 		bch_err(c, "insufficient space in superblock for sb_field_ext");
1022 		ret = -BCH_ERR_ENOSPC_sb;
1023 		goto err;
1024 	}
1025 
1026 	for_each_rw_member(c, ca)
1027 		bch2_dev_allocator_add(c, ca);
1028 	bch2_recalc_capacity(c);
1029 
1030 	ret = BCH_SB_INITIALIZED(c->disk_sb.sb)
1031 		? bch2_fs_recovery(c)
1032 		: bch2_fs_initialize(c);
1033 	if (ret)
1034 		goto err;
1035 
1036 	ret = bch2_opts_check_may_set(c);
1037 	if (ret)
1038 		goto err;
1039 
1040 	if (bch2_fs_init_fault("fs_start")) {
1041 		bch_err(c, "fs_start fault injected");
1042 		ret = -EINVAL;
1043 		goto err;
1044 	}
1045 
1046 	set_bit(BCH_FS_started, &c->flags);
1047 
1048 	if (c->opts.read_only) {
1049 		bch2_fs_read_only(c);
1050 	} else {
1051 		ret = !test_bit(BCH_FS_rw, &c->flags)
1052 			? bch2_fs_read_write(c)
1053 			: bch2_fs_read_write_late(c);
1054 		if (ret)
1055 			goto err;
1056 	}
1057 
1058 	ret = 0;
1059 err:
1060 	if (ret)
1061 		bch_err_msg(c, ret, "starting filesystem");
1062 	else
1063 		bch_verbose(c, "done starting filesystem");
1064 	up_write(&c->state_lock);
1065 	return ret;
1066 }
1067 
1068 static int bch2_dev_may_add(struct bch_sb *sb, struct bch_fs *c)
1069 {
1070 	struct bch_member m = bch2_sb_member_get(sb, sb->dev_idx);
1071 
1072 	if (le16_to_cpu(sb->block_size) != block_sectors(c))
1073 		return -BCH_ERR_mismatched_block_size;
1074 
1075 	if (le16_to_cpu(m.bucket_size) <
1076 	    BCH_SB_BTREE_NODE_SIZE(c->disk_sb.sb))
1077 		return -BCH_ERR_bucket_size_too_small;
1078 
1079 	return 0;
1080 }
1081 
1082 static int bch2_dev_in_fs(struct bch_sb_handle *fs,
1083 			  struct bch_sb_handle *sb,
1084 			  struct bch_opts *opts)
1085 {
1086 	if (fs == sb)
1087 		return 0;
1088 
1089 	if (!uuid_equal(&fs->sb->uuid, &sb->sb->uuid))
1090 		return -BCH_ERR_device_not_a_member_of_filesystem;
1091 
1092 	if (!bch2_member_exists(fs->sb, sb->sb->dev_idx))
1093 		return -BCH_ERR_device_has_been_removed;
1094 
1095 	if (fs->sb->block_size != sb->sb->block_size)
1096 		return -BCH_ERR_mismatched_block_size;
1097 
1098 	if (le16_to_cpu(fs->sb->version) < bcachefs_metadata_version_member_seq ||
1099 	    le16_to_cpu(sb->sb->version) < bcachefs_metadata_version_member_seq)
1100 		return 0;
1101 
1102 	if (fs->sb->seq == sb->sb->seq &&
1103 	    fs->sb->write_time != sb->sb->write_time) {
1104 		struct printbuf buf = PRINTBUF;
1105 
1106 		prt_str(&buf, "Split brain detected between ");
1107 		prt_bdevname(&buf, sb->bdev);
1108 		prt_str(&buf, " and ");
1109 		prt_bdevname(&buf, fs->bdev);
1110 		prt_char(&buf, ':');
1111 		prt_newline(&buf);
1112 		prt_printf(&buf, "seq=%llu but write_time different, got", le64_to_cpu(sb->sb->seq));
1113 		prt_newline(&buf);
1114 
1115 		prt_bdevname(&buf, fs->bdev);
1116 		prt_char(&buf, ' ');
1117 		bch2_prt_datetime(&buf, le64_to_cpu(fs->sb->write_time));;
1118 		prt_newline(&buf);
1119 
1120 		prt_bdevname(&buf, sb->bdev);
1121 		prt_char(&buf, ' ');
1122 		bch2_prt_datetime(&buf, le64_to_cpu(sb->sb->write_time));;
1123 		prt_newline(&buf);
1124 
1125 		if (!opts->no_splitbrain_check)
1126 			prt_printf(&buf, "Not using older sb");
1127 
1128 		pr_err("%s", buf.buf);
1129 		printbuf_exit(&buf);
1130 
1131 		if (!opts->no_splitbrain_check)
1132 			return -BCH_ERR_device_splitbrain;
1133 	}
1134 
1135 	struct bch_member m = bch2_sb_member_get(fs->sb, sb->sb->dev_idx);
1136 	u64 seq_from_fs		= le64_to_cpu(m.seq);
1137 	u64 seq_from_member	= le64_to_cpu(sb->sb->seq);
1138 
1139 	if (seq_from_fs && seq_from_fs < seq_from_member) {
1140 		struct printbuf buf = PRINTBUF;
1141 
1142 		prt_str(&buf, "Split brain detected between ");
1143 		prt_bdevname(&buf, sb->bdev);
1144 		prt_str(&buf, " and ");
1145 		prt_bdevname(&buf, fs->bdev);
1146 		prt_char(&buf, ':');
1147 		prt_newline(&buf);
1148 
1149 		prt_bdevname(&buf, fs->bdev);
1150 		prt_str(&buf, " believes seq of ");
1151 		prt_bdevname(&buf, sb->bdev);
1152 		prt_printf(&buf, " to be %llu, but ", seq_from_fs);
1153 		prt_bdevname(&buf, sb->bdev);
1154 		prt_printf(&buf, " has %llu\n", seq_from_member);
1155 
1156 		if (!opts->no_splitbrain_check) {
1157 			prt_str(&buf, "Not using ");
1158 			prt_bdevname(&buf, sb->bdev);
1159 		}
1160 
1161 		pr_err("%s", buf.buf);
1162 		printbuf_exit(&buf);
1163 
1164 		if (!opts->no_splitbrain_check)
1165 			return -BCH_ERR_device_splitbrain;
1166 	}
1167 
1168 	return 0;
1169 }
1170 
1171 /* Device startup/shutdown: */
1172 
1173 static void bch2_dev_release(struct kobject *kobj)
1174 {
1175 	struct bch_dev *ca = container_of(kobj, struct bch_dev, kobj);
1176 
1177 	kfree(ca);
1178 }
1179 
1180 static void bch2_dev_free(struct bch_dev *ca)
1181 {
1182 	cancel_work_sync(&ca->io_error_work);
1183 
1184 	if (ca->kobj.state_in_sysfs &&
1185 	    ca->disk_sb.bdev)
1186 		sysfs_remove_link(bdev_kobj(ca->disk_sb.bdev), "bcachefs");
1187 
1188 	if (ca->kobj.state_in_sysfs)
1189 		kobject_del(&ca->kobj);
1190 
1191 	kfree(ca->buckets_nouse);
1192 	bch2_free_super(&ca->disk_sb);
1193 	bch2_dev_journal_exit(ca);
1194 
1195 	free_percpu(ca->io_done);
1196 	bch2_dev_buckets_free(ca);
1197 	free_page((unsigned long) ca->sb_read_scratch);
1198 
1199 	bch2_time_stats_quantiles_exit(&ca->io_latency[WRITE]);
1200 	bch2_time_stats_quantiles_exit(&ca->io_latency[READ]);
1201 
1202 	percpu_ref_exit(&ca->io_ref);
1203 #ifndef CONFIG_BCACHEFS_DEBUG
1204 	percpu_ref_exit(&ca->ref);
1205 #endif
1206 	kobject_put(&ca->kobj);
1207 }
1208 
1209 static void __bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca)
1210 {
1211 
1212 	lockdep_assert_held(&c->state_lock);
1213 
1214 	if (percpu_ref_is_zero(&ca->io_ref))
1215 		return;
1216 
1217 	__bch2_dev_read_only(c, ca);
1218 
1219 	reinit_completion(&ca->io_ref_completion);
1220 	percpu_ref_kill(&ca->io_ref);
1221 	wait_for_completion(&ca->io_ref_completion);
1222 
1223 	if (ca->kobj.state_in_sysfs) {
1224 		sysfs_remove_link(bdev_kobj(ca->disk_sb.bdev), "bcachefs");
1225 		sysfs_remove_link(&ca->kobj, "block");
1226 	}
1227 
1228 	bch2_free_super(&ca->disk_sb);
1229 	bch2_dev_journal_exit(ca);
1230 }
1231 
1232 #ifndef CONFIG_BCACHEFS_DEBUG
1233 static void bch2_dev_ref_complete(struct percpu_ref *ref)
1234 {
1235 	struct bch_dev *ca = container_of(ref, struct bch_dev, ref);
1236 
1237 	complete(&ca->ref_completion);
1238 }
1239 #endif
1240 
1241 static void bch2_dev_io_ref_complete(struct percpu_ref *ref)
1242 {
1243 	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref);
1244 
1245 	complete(&ca->io_ref_completion);
1246 }
1247 
1248 static int bch2_dev_sysfs_online(struct bch_fs *c, struct bch_dev *ca)
1249 {
1250 	int ret;
1251 
1252 	if (!c->kobj.state_in_sysfs)
1253 		return 0;
1254 
1255 	if (!ca->kobj.state_in_sysfs) {
1256 		ret = kobject_add(&ca->kobj, &c->kobj,
1257 				  "dev-%u", ca->dev_idx);
1258 		if (ret)
1259 			return ret;
1260 	}
1261 
1262 	if (ca->disk_sb.bdev) {
1263 		struct kobject *block = bdev_kobj(ca->disk_sb.bdev);
1264 
1265 		ret = sysfs_create_link(block, &ca->kobj, "bcachefs");
1266 		if (ret)
1267 			return ret;
1268 
1269 		ret = sysfs_create_link(&ca->kobj, block, "block");
1270 		if (ret)
1271 			return ret;
1272 	}
1273 
1274 	return 0;
1275 }
1276 
1277 static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
1278 					struct bch_member *member)
1279 {
1280 	struct bch_dev *ca;
1281 	unsigned i;
1282 
1283 	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
1284 	if (!ca)
1285 		return NULL;
1286 
1287 	kobject_init(&ca->kobj, &bch2_dev_ktype);
1288 	init_completion(&ca->ref_completion);
1289 	init_completion(&ca->io_ref_completion);
1290 
1291 	init_rwsem(&ca->bucket_lock);
1292 
1293 	INIT_WORK(&ca->io_error_work, bch2_io_error_work);
1294 
1295 	bch2_time_stats_quantiles_init(&ca->io_latency[READ]);
1296 	bch2_time_stats_quantiles_init(&ca->io_latency[WRITE]);
1297 
1298 	ca->mi = bch2_mi_to_cpu(member);
1299 
1300 	for (i = 0; i < ARRAY_SIZE(member->errors); i++)
1301 		atomic64_set(&ca->errors[i], le64_to_cpu(member->errors[i]));
1302 
1303 	ca->uuid = member->uuid;
1304 
1305 	ca->nr_btree_reserve = DIV_ROUND_UP(BTREE_NODE_RESERVE,
1306 			     ca->mi.bucket_size / btree_sectors(c));
1307 
1308 #ifndef CONFIG_BCACHEFS_DEBUG
1309 	if (percpu_ref_init(&ca->ref, bch2_dev_ref_complete, 0, GFP_KERNEL))
1310 		goto err;
1311 #else
1312 	atomic_long_set(&ca->ref, 1);
1313 #endif
1314 
1315 	if (percpu_ref_init(&ca->io_ref, bch2_dev_io_ref_complete,
1316 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
1317 	    !(ca->sb_read_scratch = (void *) __get_free_page(GFP_KERNEL)) ||
1318 	    bch2_dev_buckets_alloc(c, ca) ||
1319 	    !(ca->io_done	= alloc_percpu(*ca->io_done)))
1320 		goto err;
1321 
1322 	return ca;
1323 err:
1324 	bch2_dev_free(ca);
1325 	return NULL;
1326 }
1327 
1328 static void bch2_dev_attach(struct bch_fs *c, struct bch_dev *ca,
1329 			    unsigned dev_idx)
1330 {
1331 	ca->dev_idx = dev_idx;
1332 	__set_bit(ca->dev_idx, ca->self.d);
1333 	scnprintf(ca->name, sizeof(ca->name), "dev-%u", dev_idx);
1334 
1335 	ca->fs = c;
1336 	rcu_assign_pointer(c->devs[ca->dev_idx], ca);
1337 
1338 	if (bch2_dev_sysfs_online(c, ca))
1339 		pr_warn("error creating sysfs objects");
1340 }
1341 
1342 static int bch2_dev_alloc(struct bch_fs *c, unsigned dev_idx)
1343 {
1344 	struct bch_member member = bch2_sb_member_get(c->disk_sb.sb, dev_idx);
1345 	struct bch_dev *ca = NULL;
1346 	int ret = 0;
1347 
1348 	if (bch2_fs_init_fault("dev_alloc"))
1349 		goto err;
1350 
1351 	ca = __bch2_dev_alloc(c, &member);
1352 	if (!ca)
1353 		goto err;
1354 
1355 	ca->fs = c;
1356 
1357 	bch2_dev_attach(c, ca, dev_idx);
1358 	return ret;
1359 err:
1360 	if (ca)
1361 		bch2_dev_free(ca);
1362 	return -BCH_ERR_ENOMEM_dev_alloc;
1363 }
1364 
1365 static int __bch2_dev_attach_bdev(struct bch_dev *ca, struct bch_sb_handle *sb)
1366 {
1367 	unsigned ret;
1368 
1369 	if (bch2_dev_is_online(ca)) {
1370 		bch_err(ca, "already have device online in slot %u",
1371 			sb->sb->dev_idx);
1372 		return -BCH_ERR_device_already_online;
1373 	}
1374 
1375 	if (get_capacity(sb->bdev->bd_disk) <
1376 	    ca->mi.bucket_size * ca->mi.nbuckets) {
1377 		bch_err(ca, "cannot online: device too small");
1378 		return -BCH_ERR_device_size_too_small;
1379 	}
1380 
1381 	BUG_ON(!percpu_ref_is_zero(&ca->io_ref));
1382 
1383 	ret = bch2_dev_journal_init(ca, sb->sb);
1384 	if (ret)
1385 		return ret;
1386 
1387 	/* Commit: */
1388 	ca->disk_sb = *sb;
1389 	memset(sb, 0, sizeof(*sb));
1390 
1391 	ca->dev = ca->disk_sb.bdev->bd_dev;
1392 
1393 	percpu_ref_reinit(&ca->io_ref);
1394 
1395 	return 0;
1396 }
1397 
1398 static int bch2_dev_attach_bdev(struct bch_fs *c, struct bch_sb_handle *sb)
1399 {
1400 	struct bch_dev *ca;
1401 	int ret;
1402 
1403 	lockdep_assert_held(&c->state_lock);
1404 
1405 	if (le64_to_cpu(sb->sb->seq) >
1406 	    le64_to_cpu(c->disk_sb.sb->seq))
1407 		bch2_sb_to_fs(c, sb->sb);
1408 
1409 	BUG_ON(!bch2_dev_exists(c, sb->sb->dev_idx));
1410 
1411 	ca = bch2_dev_locked(c, sb->sb->dev_idx);
1412 
1413 	ret = __bch2_dev_attach_bdev(ca, sb);
1414 	if (ret)
1415 		return ret;
1416 
1417 	bch2_dev_sysfs_online(c, ca);
1418 
1419 	struct printbuf name = PRINTBUF;
1420 	prt_bdevname(&name, ca->disk_sb.bdev);
1421 
1422 	if (c->sb.nr_devices == 1)
1423 		strscpy(c->name, name.buf, sizeof(c->name));
1424 	strscpy(ca->name, name.buf, sizeof(ca->name));
1425 
1426 	printbuf_exit(&name);
1427 
1428 	rebalance_wakeup(c);
1429 	return 0;
1430 }
1431 
1432 /* Device management: */
1433 
1434 /*
1435  * Note: this function is also used by the error paths - when a particular
1436  * device sees an error, we call it to determine whether we can just set the
1437  * device RO, or - if this function returns false - we'll set the whole
1438  * filesystem RO:
1439  *
1440  * XXX: maybe we should be more explicit about whether we're changing state
1441  * because we got an error or what have you?
1442  */
1443 bool bch2_dev_state_allowed(struct bch_fs *c, struct bch_dev *ca,
1444 			    enum bch_member_state new_state, int flags)
1445 {
1446 	struct bch_devs_mask new_online_devs;
1447 	int nr_rw = 0, required;
1448 
1449 	lockdep_assert_held(&c->state_lock);
1450 
1451 	switch (new_state) {
1452 	case BCH_MEMBER_STATE_rw:
1453 		return true;
1454 	case BCH_MEMBER_STATE_ro:
1455 		if (ca->mi.state != BCH_MEMBER_STATE_rw)
1456 			return true;
1457 
1458 		/* do we have enough devices to write to?  */
1459 		for_each_member_device(c, ca2)
1460 			if (ca2 != ca)
1461 				nr_rw += ca2->mi.state == BCH_MEMBER_STATE_rw;
1462 
1463 		required = max(!(flags & BCH_FORCE_IF_METADATA_DEGRADED)
1464 			       ? c->opts.metadata_replicas
1465 			       : metadata_replicas_required(c),
1466 			       !(flags & BCH_FORCE_IF_DATA_DEGRADED)
1467 			       ? c->opts.data_replicas
1468 			       : data_replicas_required(c));
1469 
1470 		return nr_rw >= required;
1471 	case BCH_MEMBER_STATE_failed:
1472 	case BCH_MEMBER_STATE_spare:
1473 		if (ca->mi.state != BCH_MEMBER_STATE_rw &&
1474 		    ca->mi.state != BCH_MEMBER_STATE_ro)
1475 			return true;
1476 
1477 		/* do we have enough devices to read from?  */
1478 		new_online_devs = bch2_online_devs(c);
1479 		__clear_bit(ca->dev_idx, new_online_devs.d);
1480 
1481 		return bch2_have_enough_devs(c, new_online_devs, flags, false);
1482 	default:
1483 		BUG();
1484 	}
1485 }
1486 
1487 static bool bch2_fs_may_start(struct bch_fs *c)
1488 {
1489 	struct bch_dev *ca;
1490 	unsigned i, flags = 0;
1491 
1492 	if (c->opts.very_degraded)
1493 		flags |= BCH_FORCE_IF_DEGRADED|BCH_FORCE_IF_LOST;
1494 
1495 	if (c->opts.degraded)
1496 		flags |= BCH_FORCE_IF_DEGRADED;
1497 
1498 	if (!c->opts.degraded &&
1499 	    !c->opts.very_degraded) {
1500 		mutex_lock(&c->sb_lock);
1501 
1502 		for (i = 0; i < c->disk_sb.sb->nr_devices; i++) {
1503 			if (!bch2_member_exists(c->disk_sb.sb, i))
1504 				continue;
1505 
1506 			ca = bch2_dev_locked(c, i);
1507 
1508 			if (!bch2_dev_is_online(ca) &&
1509 			    (ca->mi.state == BCH_MEMBER_STATE_rw ||
1510 			     ca->mi.state == BCH_MEMBER_STATE_ro)) {
1511 				mutex_unlock(&c->sb_lock);
1512 				return false;
1513 			}
1514 		}
1515 		mutex_unlock(&c->sb_lock);
1516 	}
1517 
1518 	return bch2_have_enough_devs(c, bch2_online_devs(c), flags, true);
1519 }
1520 
1521 static void __bch2_dev_read_only(struct bch_fs *c, struct bch_dev *ca)
1522 {
1523 	/*
1524 	 * The allocator thread itself allocates btree nodes, so stop it first:
1525 	 */
1526 	bch2_dev_allocator_remove(c, ca);
1527 	bch2_dev_journal_stop(&c->journal, ca);
1528 }
1529 
1530 static void __bch2_dev_read_write(struct bch_fs *c, struct bch_dev *ca)
1531 {
1532 	lockdep_assert_held(&c->state_lock);
1533 
1534 	BUG_ON(ca->mi.state != BCH_MEMBER_STATE_rw);
1535 
1536 	bch2_dev_allocator_add(c, ca);
1537 	bch2_recalc_capacity(c);
1538 }
1539 
1540 int __bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1541 			 enum bch_member_state new_state, int flags)
1542 {
1543 	struct bch_member *m;
1544 	int ret = 0;
1545 
1546 	if (ca->mi.state == new_state)
1547 		return 0;
1548 
1549 	if (!bch2_dev_state_allowed(c, ca, new_state, flags))
1550 		return -BCH_ERR_device_state_not_allowed;
1551 
1552 	if (new_state != BCH_MEMBER_STATE_rw)
1553 		__bch2_dev_read_only(c, ca);
1554 
1555 	bch_notice(ca, "%s", bch2_member_states[new_state]);
1556 
1557 	mutex_lock(&c->sb_lock);
1558 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
1559 	SET_BCH_MEMBER_STATE(m, new_state);
1560 	bch2_write_super(c);
1561 	mutex_unlock(&c->sb_lock);
1562 
1563 	if (new_state == BCH_MEMBER_STATE_rw)
1564 		__bch2_dev_read_write(c, ca);
1565 
1566 	rebalance_wakeup(c);
1567 
1568 	return ret;
1569 }
1570 
1571 int bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1572 		       enum bch_member_state new_state, int flags)
1573 {
1574 	int ret;
1575 
1576 	down_write(&c->state_lock);
1577 	ret = __bch2_dev_set_state(c, ca, new_state, flags);
1578 	up_write(&c->state_lock);
1579 
1580 	return ret;
1581 }
1582 
1583 /* Device add/removal: */
1584 
1585 static int bch2_dev_remove_alloc(struct bch_fs *c, struct bch_dev *ca)
1586 {
1587 	struct bpos start	= POS(ca->dev_idx, 0);
1588 	struct bpos end		= POS(ca->dev_idx, U64_MAX);
1589 	int ret;
1590 
1591 	/*
1592 	 * We clear the LRU and need_discard btrees first so that we don't race
1593 	 * with bch2_do_invalidates() and bch2_do_discards()
1594 	 */
1595 	ret =   bch2_btree_delete_range(c, BTREE_ID_lru, start, end,
1596 					BTREE_TRIGGER_norun, NULL) ?:
1597 		bch2_btree_delete_range(c, BTREE_ID_need_discard, start, end,
1598 					BTREE_TRIGGER_norun, NULL) ?:
1599 		bch2_btree_delete_range(c, BTREE_ID_freespace, start, end,
1600 					BTREE_TRIGGER_norun, NULL) ?:
1601 		bch2_btree_delete_range(c, BTREE_ID_backpointers, start, end,
1602 					BTREE_TRIGGER_norun, NULL) ?:
1603 		bch2_btree_delete_range(c, BTREE_ID_alloc, start, end,
1604 					BTREE_TRIGGER_norun, NULL) ?:
1605 		bch2_btree_delete_range(c, BTREE_ID_bucket_gens, start, end,
1606 					BTREE_TRIGGER_norun, NULL);
1607 	bch_err_msg(c, ret, "removing dev alloc info");
1608 	return ret;
1609 }
1610 
1611 int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
1612 {
1613 	struct bch_member *m;
1614 	unsigned dev_idx = ca->dev_idx, data;
1615 	int ret;
1616 
1617 	down_write(&c->state_lock);
1618 
1619 	/*
1620 	 * We consume a reference to ca->ref, regardless of whether we succeed
1621 	 * or fail:
1622 	 */
1623 	bch2_dev_put(ca);
1624 
1625 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1626 		bch_err(ca, "Cannot remove without losing data");
1627 		ret = -BCH_ERR_device_state_not_allowed;
1628 		goto err;
1629 	}
1630 
1631 	__bch2_dev_read_only(c, ca);
1632 
1633 	ret = bch2_dev_data_drop(c, ca->dev_idx, flags);
1634 	bch_err_msg(ca, ret, "bch2_dev_data_drop()");
1635 	if (ret)
1636 		goto err;
1637 
1638 	ret = bch2_dev_remove_alloc(c, ca);
1639 	bch_err_msg(ca, ret, "bch2_dev_remove_alloc()");
1640 	if (ret)
1641 		goto err;
1642 
1643 	ret = bch2_journal_flush_device_pins(&c->journal, ca->dev_idx);
1644 	bch_err_msg(ca, ret, "bch2_journal_flush_device_pins()");
1645 	if (ret)
1646 		goto err;
1647 
1648 	ret = bch2_journal_flush(&c->journal);
1649 	bch_err_msg(ca, ret, "bch2_journal_flush()");
1650 	if (ret)
1651 		goto err;
1652 
1653 	ret = bch2_replicas_gc2(c);
1654 	bch_err_msg(ca, ret, "bch2_replicas_gc2()");
1655 	if (ret)
1656 		goto err;
1657 
1658 	data = bch2_dev_has_data(c, ca);
1659 	if (data) {
1660 		struct printbuf data_has = PRINTBUF;
1661 
1662 		prt_bitflags(&data_has, __bch2_data_types, data);
1663 		bch_err(ca, "Remove failed, still has data (%s)", data_has.buf);
1664 		printbuf_exit(&data_has);
1665 		ret = -EBUSY;
1666 		goto err;
1667 	}
1668 
1669 	__bch2_dev_offline(c, ca);
1670 
1671 	mutex_lock(&c->sb_lock);
1672 	rcu_assign_pointer(c->devs[ca->dev_idx], NULL);
1673 	mutex_unlock(&c->sb_lock);
1674 
1675 #ifndef CONFIG_BCACHEFS_DEBUG
1676 	percpu_ref_kill(&ca->ref);
1677 #else
1678 	ca->dying = true;
1679 	bch2_dev_put(ca);
1680 #endif
1681 	wait_for_completion(&ca->ref_completion);
1682 
1683 	bch2_dev_free(ca);
1684 
1685 	/*
1686 	 * At this point the device object has been removed in-core, but the
1687 	 * on-disk journal might still refer to the device index via sb device
1688 	 * usage entries. Recovery fails if it sees usage information for an
1689 	 * invalid device. Flush journal pins to push the back of the journal
1690 	 * past now invalid device index references before we update the
1691 	 * superblock, but after the device object has been removed so any
1692 	 * further journal writes elide usage info for the device.
1693 	 */
1694 	bch2_journal_flush_all_pins(&c->journal);
1695 
1696 	/*
1697 	 * Free this device's slot in the bch_member array - all pointers to
1698 	 * this device must be gone:
1699 	 */
1700 	mutex_lock(&c->sb_lock);
1701 	m = bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx);
1702 	memset(&m->uuid, 0, sizeof(m->uuid));
1703 
1704 	bch2_write_super(c);
1705 
1706 	mutex_unlock(&c->sb_lock);
1707 	up_write(&c->state_lock);
1708 
1709 	bch2_dev_usage_journal_reserve(c);
1710 	return 0;
1711 err:
1712 	if (ca->mi.state == BCH_MEMBER_STATE_rw &&
1713 	    !percpu_ref_is_zero(&ca->io_ref))
1714 		__bch2_dev_read_write(c, ca);
1715 	up_write(&c->state_lock);
1716 	return ret;
1717 }
1718 
1719 /* Add new device to running filesystem: */
1720 int bch2_dev_add(struct bch_fs *c, const char *path)
1721 {
1722 	struct bch_opts opts = bch2_opts_empty();
1723 	struct bch_sb_handle sb;
1724 	struct bch_dev *ca = NULL;
1725 	struct bch_sb_field_members_v2 *mi;
1726 	struct bch_member dev_mi;
1727 	unsigned dev_idx, nr_devices, u64s;
1728 	struct printbuf errbuf = PRINTBUF;
1729 	struct printbuf label = PRINTBUF;
1730 	int ret;
1731 
1732 	ret = bch2_read_super(path, &opts, &sb);
1733 	bch_err_msg(c, ret, "reading super");
1734 	if (ret)
1735 		goto err;
1736 
1737 	dev_mi = bch2_sb_member_get(sb.sb, sb.sb->dev_idx);
1738 
1739 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1740 		bch2_disk_path_to_text_sb(&label, sb.sb, BCH_MEMBER_GROUP(&dev_mi) - 1);
1741 		if (label.allocation_failure) {
1742 			ret = -ENOMEM;
1743 			goto err;
1744 		}
1745 	}
1746 
1747 	ret = bch2_dev_may_add(sb.sb, c);
1748 	if (ret)
1749 		goto err;
1750 
1751 	ca = __bch2_dev_alloc(c, &dev_mi);
1752 	if (!ca) {
1753 		ret = -ENOMEM;
1754 		goto err;
1755 	}
1756 
1757 	bch2_dev_usage_init(ca);
1758 
1759 	ret = __bch2_dev_attach_bdev(ca, &sb);
1760 	if (ret)
1761 		goto err;
1762 
1763 	ret = bch2_dev_journal_alloc(ca);
1764 	bch_err_msg(c, ret, "allocating journal");
1765 	if (ret)
1766 		goto err;
1767 
1768 	down_write(&c->state_lock);
1769 	mutex_lock(&c->sb_lock);
1770 
1771 	ret = bch2_sb_from_fs(c, ca);
1772 	bch_err_msg(c, ret, "setting up new superblock");
1773 	if (ret)
1774 		goto err_unlock;
1775 
1776 	if (dynamic_fault("bcachefs:add:no_slot"))
1777 		goto no_slot;
1778 
1779 	if (c->sb.nr_devices < BCH_SB_MEMBERS_MAX) {
1780 		dev_idx = c->sb.nr_devices;
1781 		goto have_slot;
1782 	}
1783 
1784 	int best = -1;
1785 	u64 best_last_mount = 0;
1786 	for (dev_idx = 0; dev_idx < BCH_SB_MEMBERS_MAX; dev_idx++) {
1787 		struct bch_member m = bch2_sb_member_get(c->disk_sb.sb, dev_idx);
1788 		if (bch2_member_alive(&m))
1789 			continue;
1790 
1791 		u64 last_mount = le64_to_cpu(m.last_mount);
1792 		if (best < 0 || last_mount < best_last_mount) {
1793 			best = dev_idx;
1794 			best_last_mount = last_mount;
1795 		}
1796 	}
1797 	if (best >= 0) {
1798 		dev_idx = best;
1799 		goto have_slot;
1800 	}
1801 no_slot:
1802 	ret = -BCH_ERR_ENOSPC_sb_members;
1803 	bch_err_msg(c, ret, "setting up new superblock");
1804 	goto err_unlock;
1805 
1806 have_slot:
1807 	nr_devices = max_t(unsigned, dev_idx + 1, c->sb.nr_devices);
1808 
1809 	mi = bch2_sb_field_get(c->disk_sb.sb, members_v2);
1810 	u64s = DIV_ROUND_UP(sizeof(struct bch_sb_field_members_v2) +
1811 			    le16_to_cpu(mi->member_bytes) * nr_devices, sizeof(u64));
1812 
1813 	mi = bch2_sb_field_resize(&c->disk_sb, members_v2, u64s);
1814 	if (!mi) {
1815 		ret = -BCH_ERR_ENOSPC_sb_members;
1816 		bch_err_msg(c, ret, "setting up new superblock");
1817 		goto err_unlock;
1818 	}
1819 	struct bch_member *m = bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx);
1820 
1821 	/* success: */
1822 
1823 	*m = dev_mi;
1824 	m->last_mount = cpu_to_le64(ktime_get_real_seconds());
1825 	c->disk_sb.sb->nr_devices	= nr_devices;
1826 
1827 	ca->disk_sb.sb->dev_idx	= dev_idx;
1828 	bch2_dev_attach(c, ca, dev_idx);
1829 
1830 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1831 		ret = __bch2_dev_group_set(c, ca, label.buf);
1832 		bch_err_msg(c, ret, "creating new label");
1833 		if (ret)
1834 			goto err_unlock;
1835 	}
1836 
1837 	bch2_write_super(c);
1838 	mutex_unlock(&c->sb_lock);
1839 
1840 	bch2_dev_usage_journal_reserve(c);
1841 
1842 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1843 	bch_err_msg(ca, ret, "marking new superblock");
1844 	if (ret)
1845 		goto err_late;
1846 
1847 	ret = bch2_fs_freespace_init(c);
1848 	bch_err_msg(ca, ret, "initializing free space");
1849 	if (ret)
1850 		goto err_late;
1851 
1852 	ca->new_fs_bucket_idx = 0;
1853 
1854 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1855 		__bch2_dev_read_write(c, ca);
1856 
1857 	up_write(&c->state_lock);
1858 	return 0;
1859 
1860 err_unlock:
1861 	mutex_unlock(&c->sb_lock);
1862 	up_write(&c->state_lock);
1863 err:
1864 	if (ca)
1865 		bch2_dev_free(ca);
1866 	bch2_free_super(&sb);
1867 	printbuf_exit(&label);
1868 	printbuf_exit(&errbuf);
1869 	bch_err_fn(c, ret);
1870 	return ret;
1871 err_late:
1872 	up_write(&c->state_lock);
1873 	ca = NULL;
1874 	goto err;
1875 }
1876 
1877 /* Hot add existing device to running filesystem: */
1878 int bch2_dev_online(struct bch_fs *c, const char *path)
1879 {
1880 	struct bch_opts opts = bch2_opts_empty();
1881 	struct bch_sb_handle sb = { NULL };
1882 	struct bch_dev *ca;
1883 	unsigned dev_idx;
1884 	int ret;
1885 
1886 	down_write(&c->state_lock);
1887 
1888 	ret = bch2_read_super(path, &opts, &sb);
1889 	if (ret) {
1890 		up_write(&c->state_lock);
1891 		return ret;
1892 	}
1893 
1894 	dev_idx = sb.sb->dev_idx;
1895 
1896 	ret = bch2_dev_in_fs(&c->disk_sb, &sb, &c->opts);
1897 	bch_err_msg(c, ret, "bringing %s online", path);
1898 	if (ret)
1899 		goto err;
1900 
1901 	ret = bch2_dev_attach_bdev(c, &sb);
1902 	if (ret)
1903 		goto err;
1904 
1905 	ca = bch2_dev_locked(c, dev_idx);
1906 
1907 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1908 	bch_err_msg(c, ret, "bringing %s online: error from bch2_trans_mark_dev_sb", path);
1909 	if (ret)
1910 		goto err;
1911 
1912 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1913 		__bch2_dev_read_write(c, ca);
1914 
1915 	if (!ca->mi.freespace_initialized) {
1916 		ret = bch2_dev_freespace_init(c, ca, 0, ca->mi.nbuckets);
1917 		bch_err_msg(ca, ret, "initializing free space");
1918 		if (ret)
1919 			goto err;
1920 	}
1921 
1922 	if (!ca->journal.nr) {
1923 		ret = bch2_dev_journal_alloc(ca);
1924 		bch_err_msg(ca, ret, "allocating journal");
1925 		if (ret)
1926 			goto err;
1927 	}
1928 
1929 	mutex_lock(&c->sb_lock);
1930 	bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount =
1931 		cpu_to_le64(ktime_get_real_seconds());
1932 	bch2_write_super(c);
1933 	mutex_unlock(&c->sb_lock);
1934 
1935 	up_write(&c->state_lock);
1936 	return 0;
1937 err:
1938 	up_write(&c->state_lock);
1939 	bch2_free_super(&sb);
1940 	return ret;
1941 }
1942 
1943 int bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca, int flags)
1944 {
1945 	down_write(&c->state_lock);
1946 
1947 	if (!bch2_dev_is_online(ca)) {
1948 		bch_err(ca, "Already offline");
1949 		up_write(&c->state_lock);
1950 		return 0;
1951 	}
1952 
1953 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1954 		bch_err(ca, "Cannot offline required disk");
1955 		up_write(&c->state_lock);
1956 		return -BCH_ERR_device_state_not_allowed;
1957 	}
1958 
1959 	__bch2_dev_offline(c, ca);
1960 
1961 	up_write(&c->state_lock);
1962 	return 0;
1963 }
1964 
1965 int bch2_dev_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
1966 {
1967 	struct bch_member *m;
1968 	u64 old_nbuckets;
1969 	int ret = 0;
1970 
1971 	down_write(&c->state_lock);
1972 	old_nbuckets = ca->mi.nbuckets;
1973 
1974 	if (nbuckets < ca->mi.nbuckets) {
1975 		bch_err(ca, "Cannot shrink yet");
1976 		ret = -EINVAL;
1977 		goto err;
1978 	}
1979 
1980 	if (nbuckets > BCH_MEMBER_NBUCKETS_MAX) {
1981 		bch_err(ca, "New device size too big (%llu greater than max %u)",
1982 			nbuckets, BCH_MEMBER_NBUCKETS_MAX);
1983 		ret = -BCH_ERR_device_size_too_big;
1984 		goto err;
1985 	}
1986 
1987 	if (bch2_dev_is_online(ca) &&
1988 	    get_capacity(ca->disk_sb.bdev->bd_disk) <
1989 	    ca->mi.bucket_size * nbuckets) {
1990 		bch_err(ca, "New size larger than device");
1991 		ret = -BCH_ERR_device_size_too_small;
1992 		goto err;
1993 	}
1994 
1995 	ret = bch2_dev_buckets_resize(c, ca, nbuckets);
1996 	bch_err_msg(ca, ret, "resizing buckets");
1997 	if (ret)
1998 		goto err;
1999 
2000 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
2001 	if (ret)
2002 		goto err;
2003 
2004 	mutex_lock(&c->sb_lock);
2005 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
2006 	m->nbuckets = cpu_to_le64(nbuckets);
2007 
2008 	bch2_write_super(c);
2009 	mutex_unlock(&c->sb_lock);
2010 
2011 	if (ca->mi.freespace_initialized) {
2012 		ret = bch2_dev_freespace_init(c, ca, old_nbuckets, nbuckets);
2013 		if (ret)
2014 			goto err;
2015 
2016 		/*
2017 		 * XXX: this is all wrong transactionally - we'll be able to do
2018 		 * this correctly after the disk space accounting rewrite
2019 		 */
2020 		ca->usage_base->d[BCH_DATA_free].buckets += nbuckets - old_nbuckets;
2021 	}
2022 
2023 	bch2_recalc_capacity(c);
2024 err:
2025 	up_write(&c->state_lock);
2026 	return ret;
2027 }
2028 
2029 /* return with ref on ca->ref: */
2030 struct bch_dev *bch2_dev_lookup(struct bch_fs *c, const char *name)
2031 {
2032 	for_each_member_device(c, ca)
2033 		if (!strcmp(name, ca->name))
2034 			return ca;
2035 	return ERR_PTR(-BCH_ERR_ENOENT_dev_not_found);
2036 }
2037 
2038 /* Filesystem open: */
2039 
2040 static inline int sb_cmp(struct bch_sb *l, struct bch_sb *r)
2041 {
2042 	return  cmp_int(le64_to_cpu(l->seq), le64_to_cpu(r->seq)) ?:
2043 		cmp_int(le64_to_cpu(l->write_time), le64_to_cpu(r->write_time));
2044 }
2045 
2046 struct bch_fs *bch2_fs_open(char * const *devices, unsigned nr_devices,
2047 			    struct bch_opts opts)
2048 {
2049 	DARRAY(struct bch_sb_handle) sbs = { 0 };
2050 	struct bch_fs *c = NULL;
2051 	struct bch_sb_handle *best = NULL;
2052 	struct printbuf errbuf = PRINTBUF;
2053 	int ret = 0;
2054 
2055 	if (!try_module_get(THIS_MODULE))
2056 		return ERR_PTR(-ENODEV);
2057 
2058 	if (!nr_devices) {
2059 		ret = -EINVAL;
2060 		goto err;
2061 	}
2062 
2063 	ret = darray_make_room(&sbs, nr_devices);
2064 	if (ret)
2065 		goto err;
2066 
2067 	for (unsigned i = 0; i < nr_devices; i++) {
2068 		struct bch_sb_handle sb = { NULL };
2069 
2070 		ret = bch2_read_super(devices[i], &opts, &sb);
2071 		if (ret)
2072 			goto err;
2073 
2074 		BUG_ON(darray_push(&sbs, sb));
2075 	}
2076 
2077 	if (opts.nochanges && !opts.read_only) {
2078 		ret = -BCH_ERR_erofs_nochanges;
2079 		goto err_print;
2080 	}
2081 
2082 	darray_for_each(sbs, sb)
2083 		if (!best || sb_cmp(sb->sb, best->sb) > 0)
2084 			best = sb;
2085 
2086 	darray_for_each_reverse(sbs, sb) {
2087 		ret = bch2_dev_in_fs(best, sb, &opts);
2088 
2089 		if (ret == -BCH_ERR_device_has_been_removed ||
2090 		    ret == -BCH_ERR_device_splitbrain) {
2091 			bch2_free_super(sb);
2092 			darray_remove_item(&sbs, sb);
2093 			best -= best > sb;
2094 			ret = 0;
2095 			continue;
2096 		}
2097 
2098 		if (ret)
2099 			goto err_print;
2100 	}
2101 
2102 	c = bch2_fs_alloc(best->sb, opts);
2103 	ret = PTR_ERR_OR_ZERO(c);
2104 	if (ret)
2105 		goto err;
2106 
2107 	down_write(&c->state_lock);
2108 	darray_for_each(sbs, sb) {
2109 		ret = bch2_dev_attach_bdev(c, sb);
2110 		if (ret) {
2111 			up_write(&c->state_lock);
2112 			goto err;
2113 		}
2114 	}
2115 	up_write(&c->state_lock);
2116 
2117 	if (!bch2_fs_may_start(c)) {
2118 		ret = -BCH_ERR_insufficient_devices_to_start;
2119 		goto err_print;
2120 	}
2121 
2122 	if (!c->opts.nostart) {
2123 		ret = bch2_fs_start(c);
2124 		if (ret)
2125 			goto err;
2126 	}
2127 out:
2128 	darray_for_each(sbs, sb)
2129 		bch2_free_super(sb);
2130 	darray_exit(&sbs);
2131 	printbuf_exit(&errbuf);
2132 	module_put(THIS_MODULE);
2133 	return c;
2134 err_print:
2135 	pr_err("bch_fs_open err opening %s: %s",
2136 	       devices[0], bch2_err_str(ret));
2137 err:
2138 	if (!IS_ERR_OR_NULL(c))
2139 		bch2_fs_stop(c);
2140 	c = ERR_PTR(ret);
2141 	goto out;
2142 }
2143 
2144 /* Global interfaces/init */
2145 
2146 static void bcachefs_exit(void)
2147 {
2148 	bch2_debug_exit();
2149 	bch2_vfs_exit();
2150 	bch2_chardev_exit();
2151 	bch2_btree_key_cache_exit();
2152 	if (bcachefs_kset)
2153 		kset_unregister(bcachefs_kset);
2154 }
2155 
2156 static int __init bcachefs_init(void)
2157 {
2158 	bch2_bkey_pack_test();
2159 
2160 	if (!(bcachefs_kset = kset_create_and_add("bcachefs", NULL, fs_kobj)) ||
2161 	    bch2_btree_key_cache_init() ||
2162 	    bch2_chardev_init() ||
2163 	    bch2_vfs_init() ||
2164 	    bch2_debug_init())
2165 		goto err;
2166 
2167 	return 0;
2168 err:
2169 	bcachefs_exit();
2170 	return -ENOMEM;
2171 }
2172 
2173 #define BCH_DEBUG_PARAM(name, description)			\
2174 	bool bch2_##name;					\
2175 	module_param_named(name, bch2_##name, bool, 0644);	\
2176 	MODULE_PARM_DESC(name, description);
2177 BCH_DEBUG_PARAMS()
2178 #undef BCH_DEBUG_PARAM
2179 
2180 __maybe_unused
2181 static unsigned bch2_metadata_version = bcachefs_metadata_version_current;
2182 module_param_named(version, bch2_metadata_version, uint, 0400);
2183 
2184 module_exit(bcachefs_exit);
2185 module_init(bcachefs_init);
2186