xref: /linux/fs/bcachefs/super.c (revision 6315d93541f8a5f77c5ef5c4f25233e66d189603)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * bcachefs setup/teardown code, and some metadata io - read a superblock and
4  * figure out what to do with it.
5  *
6  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
7  * Copyright 2012 Google, Inc.
8  */
9 
10 #include "bcachefs.h"
11 #include "alloc_background.h"
12 #include "alloc_foreground.h"
13 #include "bkey_sort.h"
14 #include "btree_cache.h"
15 #include "btree_gc.h"
16 #include "btree_journal_iter.h"
17 #include "btree_key_cache.h"
18 #include "btree_node_scan.h"
19 #include "btree_update_interior.h"
20 #include "btree_io.h"
21 #include "btree_write_buffer.h"
22 #include "buckets_waiting_for_journal.h"
23 #include "chardev.h"
24 #include "checksum.h"
25 #include "clock.h"
26 #include "compress.h"
27 #include "debug.h"
28 #include "disk_accounting.h"
29 #include "disk_groups.h"
30 #include "ec.h"
31 #include "errcode.h"
32 #include "error.h"
33 #include "fs.h"
34 #include "fs-io.h"
35 #include "fs-io-buffered.h"
36 #include "fs-io-direct.h"
37 #include "fsck.h"
38 #include "inode.h"
39 #include "io_read.h"
40 #include "io_write.h"
41 #include "journal.h"
42 #include "journal_reclaim.h"
43 #include "journal_seq_blacklist.h"
44 #include "move.h"
45 #include "migrate.h"
46 #include "movinggc.h"
47 #include "nocow_locking.h"
48 #include "quota.h"
49 #include "rebalance.h"
50 #include "recovery.h"
51 #include "replicas.h"
52 #include "sb-clean.h"
53 #include "sb-counters.h"
54 #include "sb-errors.h"
55 #include "sb-members.h"
56 #include "snapshot.h"
57 #include "subvolume.h"
58 #include "super.h"
59 #include "super-io.h"
60 #include "sysfs.h"
61 #include "thread_with_file.h"
62 #include "trace.h"
63 
64 #include <linux/backing-dev.h>
65 #include <linux/blkdev.h>
66 #include <linux/debugfs.h>
67 #include <linux/device.h>
68 #include <linux/idr.h>
69 #include <linux/module.h>
70 #include <linux/percpu.h>
71 #include <linux/random.h>
72 #include <linux/sysfs.h>
73 #include <crypto/hash.h>
74 
75 MODULE_LICENSE("GPL");
76 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
77 MODULE_DESCRIPTION("bcachefs filesystem");
78 MODULE_SOFTDEP("pre: chacha20");
79 MODULE_SOFTDEP("pre: poly1305");
80 MODULE_SOFTDEP("pre: xxhash");
81 
82 const char * const bch2_fs_flag_strs[] = {
83 #define x(n)		#n,
84 	BCH_FS_FLAGS()
85 #undef x
86 	NULL
87 };
88 
89 void bch2_print_str(struct bch_fs *c, const char *str)
90 {
91 #ifdef __KERNEL__
92 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
93 
94 	if (unlikely(stdio)) {
95 		bch2_stdio_redirect_printf(stdio, true, "%s", str);
96 		return;
97 	}
98 #endif
99 	bch2_print_string_as_lines(KERN_ERR, str);
100 }
101 
102 __printf(2, 0)
103 static void bch2_print_maybe_redirect(struct stdio_redirect *stdio, const char *fmt, va_list args)
104 {
105 #ifdef __KERNEL__
106 	if (unlikely(stdio)) {
107 		if (fmt[0] == KERN_SOH[0])
108 			fmt += 2;
109 
110 		bch2_stdio_redirect_vprintf(stdio, true, fmt, args);
111 		return;
112 	}
113 #endif
114 	vprintk(fmt, args);
115 }
116 
117 void bch2_print_opts(struct bch_opts *opts, const char *fmt, ...)
118 {
119 	struct stdio_redirect *stdio = (void *)(unsigned long)opts->stdio;
120 
121 	va_list args;
122 	va_start(args, fmt);
123 	bch2_print_maybe_redirect(stdio, fmt, args);
124 	va_end(args);
125 }
126 
127 void __bch2_print(struct bch_fs *c, const char *fmt, ...)
128 {
129 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);
130 
131 	va_list args;
132 	va_start(args, fmt);
133 	bch2_print_maybe_redirect(stdio, fmt, args);
134 	va_end(args);
135 }
136 
137 #define KTYPE(type)							\
138 static const struct attribute_group type ## _group = {			\
139 	.attrs = type ## _files						\
140 };									\
141 									\
142 static const struct attribute_group *type ## _groups[] = {		\
143 	&type ## _group,						\
144 	NULL								\
145 };									\
146 									\
147 static const struct kobj_type type ## _ktype = {			\
148 	.release	= type ## _release,				\
149 	.sysfs_ops	= &type ## _sysfs_ops,				\
150 	.default_groups = type ## _groups				\
151 }
152 
153 static void bch2_fs_release(struct kobject *);
154 static void bch2_dev_release(struct kobject *);
155 static void bch2_fs_counters_release(struct kobject *k)
156 {
157 }
158 
159 static void bch2_fs_internal_release(struct kobject *k)
160 {
161 }
162 
163 static void bch2_fs_opts_dir_release(struct kobject *k)
164 {
165 }
166 
167 static void bch2_fs_time_stats_release(struct kobject *k)
168 {
169 }
170 
171 KTYPE(bch2_fs);
172 KTYPE(bch2_fs_counters);
173 KTYPE(bch2_fs_internal);
174 KTYPE(bch2_fs_opts_dir);
175 KTYPE(bch2_fs_time_stats);
176 KTYPE(bch2_dev);
177 
178 static struct kset *bcachefs_kset;
179 static LIST_HEAD(bch_fs_list);
180 static DEFINE_MUTEX(bch_fs_list_lock);
181 
182 DECLARE_WAIT_QUEUE_HEAD(bch2_read_only_wait);
183 
184 static void bch2_dev_unlink(struct bch_dev *);
185 static void bch2_dev_free(struct bch_dev *);
186 static int bch2_dev_alloc(struct bch_fs *, unsigned);
187 static int bch2_dev_sysfs_online(struct bch_fs *, struct bch_dev *);
188 static void bch2_dev_io_ref_stop(struct bch_dev *, int);
189 static void __bch2_dev_read_only(struct bch_fs *, struct bch_dev *);
190 
191 struct bch_fs *bch2_dev_to_fs(dev_t dev)
192 {
193 	struct bch_fs *c;
194 
195 	mutex_lock(&bch_fs_list_lock);
196 	rcu_read_lock();
197 
198 	list_for_each_entry(c, &bch_fs_list, list)
199 		for_each_member_device_rcu(c, ca, NULL)
200 			if (ca->disk_sb.bdev && ca->disk_sb.bdev->bd_dev == dev) {
201 				closure_get(&c->cl);
202 				goto found;
203 			}
204 	c = NULL;
205 found:
206 	rcu_read_unlock();
207 	mutex_unlock(&bch_fs_list_lock);
208 
209 	return c;
210 }
211 
212 static struct bch_fs *__bch2_uuid_to_fs(__uuid_t uuid)
213 {
214 	struct bch_fs *c;
215 
216 	lockdep_assert_held(&bch_fs_list_lock);
217 
218 	list_for_each_entry(c, &bch_fs_list, list)
219 		if (!memcmp(&c->disk_sb.sb->uuid, &uuid, sizeof(uuid)))
220 			return c;
221 
222 	return NULL;
223 }
224 
225 struct bch_fs *bch2_uuid_to_fs(__uuid_t uuid)
226 {
227 	struct bch_fs *c;
228 
229 	mutex_lock(&bch_fs_list_lock);
230 	c = __bch2_uuid_to_fs(uuid);
231 	if (c)
232 		closure_get(&c->cl);
233 	mutex_unlock(&bch_fs_list_lock);
234 
235 	return c;
236 }
237 
238 /* Filesystem RO/RW: */
239 
240 /*
241  * For startup/shutdown of RW stuff, the dependencies are:
242  *
243  * - foreground writes depend on copygc and rebalance (to free up space)
244  *
245  * - copygc and rebalance depend on mark and sweep gc (they actually probably
246  *   don't because they either reserve ahead of time or don't block if
247  *   allocations fail, but allocations can require mark and sweep gc to run
248  *   because of generation number wraparound)
249  *
250  * - all of the above depends on the allocator threads
251  *
252  * - allocator depends on the journal (when it rewrites prios and gens)
253  */
254 
255 static void __bch2_fs_read_only(struct bch_fs *c)
256 {
257 	unsigned clean_passes = 0;
258 	u64 seq = 0;
259 
260 	bch2_fs_ec_stop(c);
261 	bch2_open_buckets_stop(c, NULL, true);
262 	bch2_rebalance_stop(c);
263 	bch2_copygc_stop(c);
264 	bch2_fs_ec_flush(c);
265 
266 	bch_verbose(c, "flushing journal and stopping allocators, journal seq %llu",
267 		    journal_cur_seq(&c->journal));
268 
269 	do {
270 		clean_passes++;
271 
272 		if (bch2_btree_interior_updates_flush(c) ||
273 		    bch2_btree_write_buffer_flush_going_ro(c) ||
274 		    bch2_journal_flush_all_pins(&c->journal) ||
275 		    bch2_btree_flush_all_writes(c) ||
276 		    seq != atomic64_read(&c->journal.seq)) {
277 			seq = atomic64_read(&c->journal.seq);
278 			clean_passes = 0;
279 		}
280 	} while (clean_passes < 2);
281 
282 	bch_verbose(c, "flushing journal and stopping allocators complete, journal seq %llu",
283 		    journal_cur_seq(&c->journal));
284 
285 	if (test_bit(JOURNAL_replay_done, &c->journal.flags) &&
286 	    !test_bit(BCH_FS_emergency_ro, &c->flags))
287 		set_bit(BCH_FS_clean_shutdown, &c->flags);
288 
289 	bch2_fs_journal_stop(&c->journal);
290 
291 	bch_info(c, "%sclean shutdown complete, journal seq %llu",
292 		 test_bit(BCH_FS_clean_shutdown, &c->flags) ? "" : "un",
293 		 c->journal.seq_ondisk);
294 
295 	/*
296 	 * After stopping journal:
297 	 */
298 	for_each_member_device(c, ca) {
299 		bch2_dev_io_ref_stop(ca, WRITE);
300 		bch2_dev_allocator_remove(c, ca);
301 	}
302 }
303 
304 #ifndef BCH_WRITE_REF_DEBUG
305 static void bch2_writes_disabled(struct percpu_ref *writes)
306 {
307 	struct bch_fs *c = container_of(writes, struct bch_fs, writes);
308 
309 	set_bit(BCH_FS_write_disable_complete, &c->flags);
310 	wake_up(&bch2_read_only_wait);
311 }
312 #endif
313 
314 void bch2_fs_read_only(struct bch_fs *c)
315 {
316 	if (!test_bit(BCH_FS_rw, &c->flags)) {
317 		bch2_journal_reclaim_stop(&c->journal);
318 		return;
319 	}
320 
321 	BUG_ON(test_bit(BCH_FS_write_disable_complete, &c->flags));
322 
323 	bch_verbose(c, "going read-only");
324 
325 	/*
326 	 * Block new foreground-end write operations from starting - any new
327 	 * writes will return -EROFS:
328 	 */
329 	set_bit(BCH_FS_going_ro, &c->flags);
330 #ifndef BCH_WRITE_REF_DEBUG
331 	percpu_ref_kill(&c->writes);
332 #else
333 	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++)
334 		bch2_write_ref_put(c, i);
335 #endif
336 
337 	/*
338 	 * If we're not doing an emergency shutdown, we want to wait on
339 	 * outstanding writes to complete so they don't see spurious errors due
340 	 * to shutting down the allocator:
341 	 *
342 	 * If we are doing an emergency shutdown outstanding writes may
343 	 * hang until we shutdown the allocator so we don't want to wait
344 	 * on outstanding writes before shutting everything down - but
345 	 * we do need to wait on them before returning and signalling
346 	 * that going RO is complete:
347 	 */
348 	wait_event(bch2_read_only_wait,
349 		   test_bit(BCH_FS_write_disable_complete, &c->flags) ||
350 		   test_bit(BCH_FS_emergency_ro, &c->flags));
351 
352 	bool writes_disabled = test_bit(BCH_FS_write_disable_complete, &c->flags);
353 	if (writes_disabled)
354 		bch_verbose(c, "finished waiting for writes to stop");
355 
356 	__bch2_fs_read_only(c);
357 
358 	wait_event(bch2_read_only_wait,
359 		   test_bit(BCH_FS_write_disable_complete, &c->flags));
360 
361 	if (!writes_disabled)
362 		bch_verbose(c, "finished waiting for writes to stop");
363 
364 	clear_bit(BCH_FS_write_disable_complete, &c->flags);
365 	clear_bit(BCH_FS_going_ro, &c->flags);
366 	clear_bit(BCH_FS_rw, &c->flags);
367 
368 	if (!bch2_journal_error(&c->journal) &&
369 	    !test_bit(BCH_FS_error, &c->flags) &&
370 	    !test_bit(BCH_FS_emergency_ro, &c->flags) &&
371 	    test_bit(BCH_FS_started, &c->flags) &&
372 	    test_bit(BCH_FS_clean_shutdown, &c->flags) &&
373 	    c->recovery_pass_done >= BCH_RECOVERY_PASS_journal_replay) {
374 		BUG_ON(c->journal.last_empty_seq != journal_cur_seq(&c->journal));
375 		BUG_ON(atomic_long_read(&c->btree_cache.nr_dirty));
376 		BUG_ON(atomic_long_read(&c->btree_key_cache.nr_dirty));
377 		BUG_ON(c->btree_write_buffer.inc.keys.nr);
378 		BUG_ON(c->btree_write_buffer.flushing.keys.nr);
379 		bch2_verify_accounting_clean(c);
380 
381 		bch_verbose(c, "marking filesystem clean");
382 		bch2_fs_mark_clean(c);
383 	} else {
384 		bch_verbose(c, "done going read-only, filesystem not clean");
385 	}
386 }
387 
388 static void bch2_fs_read_only_work(struct work_struct *work)
389 {
390 	struct bch_fs *c =
391 		container_of(work, struct bch_fs, read_only_work);
392 
393 	down_write(&c->state_lock);
394 	bch2_fs_read_only(c);
395 	up_write(&c->state_lock);
396 }
397 
398 static void bch2_fs_read_only_async(struct bch_fs *c)
399 {
400 	queue_work(system_long_wq, &c->read_only_work);
401 }
402 
403 bool bch2_fs_emergency_read_only(struct bch_fs *c)
404 {
405 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
406 
407 	bch2_journal_halt(&c->journal);
408 	bch2_fs_read_only_async(c);
409 
410 	wake_up(&bch2_read_only_wait);
411 	return ret;
412 }
413 
414 bool bch2_fs_emergency_read_only_locked(struct bch_fs *c)
415 {
416 	bool ret = !test_and_set_bit(BCH_FS_emergency_ro, &c->flags);
417 
418 	bch2_journal_halt_locked(&c->journal);
419 	bch2_fs_read_only_async(c);
420 
421 	wake_up(&bch2_read_only_wait);
422 	return ret;
423 }
424 
425 static int bch2_fs_read_write_late(struct bch_fs *c)
426 {
427 	int ret;
428 
429 	/*
430 	 * Data move operations can't run until after check_snapshots has
431 	 * completed, and bch2_snapshot_is_ancestor() is available.
432 	 *
433 	 * Ideally we'd start copygc/rebalance earlier instead of waiting for
434 	 * all of recovery/fsck to complete:
435 	 */
436 	ret = bch2_copygc_start(c);
437 	if (ret) {
438 		bch_err(c, "error starting copygc thread");
439 		return ret;
440 	}
441 
442 	ret = bch2_rebalance_start(c);
443 	if (ret) {
444 		bch_err(c, "error starting rebalance thread");
445 		return ret;
446 	}
447 
448 	return 0;
449 }
450 
451 static int __bch2_fs_read_write(struct bch_fs *c, bool early)
452 {
453 	int ret;
454 
455 	BUG_ON(!test_bit(BCH_FS_may_go_rw, &c->flags));
456 
457 	if (test_bit(BCH_FS_initial_gc_unfixed, &c->flags)) {
458 		bch_err(c, "cannot go rw, unfixed btree errors");
459 		return -BCH_ERR_erofs_unfixed_errors;
460 	}
461 
462 	if (test_bit(BCH_FS_rw, &c->flags))
463 		return 0;
464 
465 	bch_info(c, "going read-write");
466 
467 	ret = bch2_sb_members_v2_init(c);
468 	if (ret)
469 		goto err;
470 
471 	clear_bit(BCH_FS_clean_shutdown, &c->flags);
472 
473 	/*
474 	 * First journal write must be a flush write: after a clean shutdown we
475 	 * don't read the journal, so the first journal write may end up
476 	 * overwriting whatever was there previously, and there must always be
477 	 * at least one non-flush write in the journal or recovery will fail:
478 	 */
479 	set_bit(JOURNAL_need_flush_write, &c->journal.flags);
480 	set_bit(JOURNAL_running, &c->journal.flags);
481 
482 	__for_each_online_member(c, ca, BIT(BCH_MEMBER_STATE_rw), READ) {
483 		bch2_dev_allocator_add(c, ca);
484 		percpu_ref_reinit(&ca->io_ref[WRITE]);
485 	}
486 	bch2_recalc_capacity(c);
487 
488 	ret = bch2_fs_mark_dirty(c);
489 	if (ret)
490 		goto err;
491 
492 	spin_lock(&c->journal.lock);
493 	bch2_journal_space_available(&c->journal);
494 	spin_unlock(&c->journal.lock);
495 
496 	ret = bch2_journal_reclaim_start(&c->journal);
497 	if (ret)
498 		goto err;
499 
500 	set_bit(BCH_FS_rw, &c->flags);
501 	set_bit(BCH_FS_was_rw, &c->flags);
502 
503 #ifndef BCH_WRITE_REF_DEBUG
504 	percpu_ref_reinit(&c->writes);
505 #else
506 	for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++) {
507 		BUG_ON(atomic_long_read(&c->writes[i]));
508 		atomic_long_inc(&c->writes[i]);
509 	}
510 #endif
511 	if (!early) {
512 		ret = bch2_fs_read_write_late(c);
513 		if (ret)
514 			goto err;
515 	}
516 
517 	bch2_do_discards(c);
518 	bch2_do_invalidates(c);
519 	bch2_do_stripe_deletes(c);
520 	bch2_do_pending_node_rewrites(c);
521 	return 0;
522 err:
523 	if (test_bit(BCH_FS_rw, &c->flags))
524 		bch2_fs_read_only(c);
525 	else
526 		__bch2_fs_read_only(c);
527 	return ret;
528 }
529 
530 int bch2_fs_read_write(struct bch_fs *c)
531 {
532 	if (c->opts.recovery_pass_last &&
533 	    c->opts.recovery_pass_last < BCH_RECOVERY_PASS_journal_replay)
534 		return -BCH_ERR_erofs_norecovery;
535 
536 	if (c->opts.nochanges)
537 		return -BCH_ERR_erofs_nochanges;
538 
539 	return __bch2_fs_read_write(c, false);
540 }
541 
542 int bch2_fs_read_write_early(struct bch_fs *c)
543 {
544 	down_write(&c->state_lock);
545 	int ret = __bch2_fs_read_write(c, true);
546 	up_write(&c->state_lock);
547 
548 	return ret;
549 }
550 
551 /* Filesystem startup/shutdown: */
552 
553 static void __bch2_fs_free(struct bch_fs *c)
554 {
555 	for (unsigned i = 0; i < BCH_TIME_STAT_NR; i++)
556 		bch2_time_stats_exit(&c->times[i]);
557 
558 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
559 	bch2_free_pending_node_rewrites(c);
560 	bch2_fs_accounting_exit(c);
561 	bch2_fs_sb_errors_exit(c);
562 	bch2_fs_counters_exit(c);
563 	bch2_fs_snapshots_exit(c);
564 	bch2_fs_quota_exit(c);
565 	bch2_fs_fs_io_direct_exit(c);
566 	bch2_fs_fs_io_buffered_exit(c);
567 	bch2_fs_fsio_exit(c);
568 	bch2_fs_vfs_exit(c);
569 	bch2_fs_ec_exit(c);
570 	bch2_fs_encryption_exit(c);
571 	bch2_fs_nocow_locking_exit(c);
572 	bch2_fs_io_write_exit(c);
573 	bch2_fs_io_read_exit(c);
574 	bch2_fs_buckets_waiting_for_journal_exit(c);
575 	bch2_fs_btree_interior_update_exit(c);
576 	bch2_fs_btree_key_cache_exit(&c->btree_key_cache);
577 	bch2_fs_btree_cache_exit(c);
578 	bch2_fs_btree_iter_exit(c);
579 	bch2_fs_replicas_exit(c);
580 	bch2_fs_journal_exit(&c->journal);
581 	bch2_io_clock_exit(&c->io_clock[WRITE]);
582 	bch2_io_clock_exit(&c->io_clock[READ]);
583 	bch2_fs_compress_exit(c);
584 	bch2_fs_btree_gc_exit(c);
585 	bch2_journal_keys_put_initial(c);
586 	bch2_find_btree_nodes_exit(&c->found_btree_nodes);
587 	BUG_ON(atomic_read(&c->journal_keys.ref));
588 	bch2_fs_btree_write_buffer_exit(c);
589 	percpu_free_rwsem(&c->mark_lock);
590 	if (c->online_reserved) {
591 		u64 v = percpu_u64_get(c->online_reserved);
592 		WARN(v, "online_reserved not 0 at shutdown: %lli", v);
593 		free_percpu(c->online_reserved);
594 	}
595 
596 	darray_exit(&c->btree_roots_extra);
597 	free_percpu(c->pcpu);
598 	free_percpu(c->usage);
599 	mempool_exit(&c->large_bkey_pool);
600 	mempool_exit(&c->btree_bounce_pool);
601 	bioset_exit(&c->btree_bio);
602 	mempool_exit(&c->fill_iter);
603 #ifndef BCH_WRITE_REF_DEBUG
604 	percpu_ref_exit(&c->writes);
605 #endif
606 	kfree(rcu_dereference_protected(c->disk_groups, 1));
607 	kfree(c->journal_seq_blacklist_table);
608 
609 	if (c->write_ref_wq)
610 		destroy_workqueue(c->write_ref_wq);
611 	if (c->btree_write_submit_wq)
612 		destroy_workqueue(c->btree_write_submit_wq);
613 	if (c->btree_read_complete_wq)
614 		destroy_workqueue(c->btree_read_complete_wq);
615 	if (c->copygc_wq)
616 		destroy_workqueue(c->copygc_wq);
617 	if (c->btree_io_complete_wq)
618 		destroy_workqueue(c->btree_io_complete_wq);
619 	if (c->btree_update_wq)
620 		destroy_workqueue(c->btree_update_wq);
621 
622 	bch2_free_super(&c->disk_sb);
623 	kvfree(c);
624 	module_put(THIS_MODULE);
625 }
626 
627 static void bch2_fs_release(struct kobject *kobj)
628 {
629 	struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
630 
631 	__bch2_fs_free(c);
632 }
633 
634 void __bch2_fs_stop(struct bch_fs *c)
635 {
636 	bch_verbose(c, "shutting down");
637 
638 	set_bit(BCH_FS_stopping, &c->flags);
639 
640 	down_write(&c->state_lock);
641 	bch2_fs_read_only(c);
642 	up_write(&c->state_lock);
643 
644 	for_each_member_device(c, ca)
645 		bch2_dev_unlink(ca);
646 
647 	if (c->kobj.state_in_sysfs)
648 		kobject_del(&c->kobj);
649 
650 	bch2_fs_debug_exit(c);
651 	bch2_fs_chardev_exit(c);
652 
653 	bch2_ro_ref_put(c);
654 	wait_event(c->ro_ref_wait, !refcount_read(&c->ro_ref));
655 
656 	kobject_put(&c->counters_kobj);
657 	kobject_put(&c->time_stats);
658 	kobject_put(&c->opts_dir);
659 	kobject_put(&c->internal);
660 
661 	/* btree prefetch might have kicked off reads in the background: */
662 	bch2_btree_flush_all_reads(c);
663 
664 	for_each_member_device(c, ca)
665 		cancel_work_sync(&ca->io_error_work);
666 
667 	cancel_work_sync(&c->read_only_work);
668 }
669 
670 void bch2_fs_free(struct bch_fs *c)
671 {
672 	unsigned i;
673 
674 	mutex_lock(&bch_fs_list_lock);
675 	list_del(&c->list);
676 	mutex_unlock(&bch_fs_list_lock);
677 
678 	closure_sync(&c->cl);
679 	closure_debug_destroy(&c->cl);
680 
681 	for (i = 0; i < c->sb.nr_devices; i++) {
682 		struct bch_dev *ca = rcu_dereference_protected(c->devs[i], true);
683 
684 		if (ca) {
685 			EBUG_ON(atomic_long_read(&ca->ref) != 1);
686 			bch2_dev_io_ref_stop(ca, READ);
687 			bch2_free_super(&ca->disk_sb);
688 			bch2_dev_free(ca);
689 		}
690 	}
691 
692 	bch_verbose(c, "shutdown complete");
693 
694 	kobject_put(&c->kobj);
695 }
696 
697 void bch2_fs_stop(struct bch_fs *c)
698 {
699 	__bch2_fs_stop(c);
700 	bch2_fs_free(c);
701 }
702 
703 static int bch2_fs_online(struct bch_fs *c)
704 {
705 	int ret = 0;
706 
707 	lockdep_assert_held(&bch_fs_list_lock);
708 
709 	if (__bch2_uuid_to_fs(c->sb.uuid)) {
710 		bch_err(c, "filesystem UUID already open");
711 		return -EINVAL;
712 	}
713 
714 	ret = bch2_fs_chardev_init(c);
715 	if (ret) {
716 		bch_err(c, "error creating character device");
717 		return ret;
718 	}
719 
720 	bch2_fs_debug_init(c);
721 
722 	ret = kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b) ?:
723 	    kobject_add(&c->internal, &c->kobj, "internal") ?:
724 	    kobject_add(&c->opts_dir, &c->kobj, "options") ?:
725 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
726 	    kobject_add(&c->time_stats, &c->kobj, "time_stats") ?:
727 #endif
728 	    kobject_add(&c->counters_kobj, &c->kobj, "counters") ?:
729 	    bch2_opts_create_sysfs_files(&c->opts_dir, OPT_FS);
730 	if (ret) {
731 		bch_err(c, "error creating sysfs objects");
732 		return ret;
733 	}
734 
735 	down_write(&c->state_lock);
736 
737 	for_each_member_device(c, ca) {
738 		ret = bch2_dev_sysfs_online(c, ca);
739 		if (ret) {
740 			bch_err(c, "error creating sysfs objects");
741 			bch2_dev_put(ca);
742 			goto err;
743 		}
744 	}
745 
746 	BUG_ON(!list_empty(&c->list));
747 	list_add(&c->list, &bch_fs_list);
748 err:
749 	up_write(&c->state_lock);
750 	return ret;
751 }
752 
753 static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
754 {
755 	struct bch_fs *c;
756 	struct printbuf name = PRINTBUF;
757 	unsigned i, iter_size;
758 	int ret = 0;
759 
760 	c = kvmalloc(sizeof(struct bch_fs), GFP_KERNEL|__GFP_ZERO);
761 	if (!c) {
762 		c = ERR_PTR(-BCH_ERR_ENOMEM_fs_alloc);
763 		goto out;
764 	}
765 
766 	c->stdio = (void *)(unsigned long) opts.stdio;
767 
768 	__module_get(THIS_MODULE);
769 
770 	closure_init(&c->cl, NULL);
771 
772 	c->kobj.kset = bcachefs_kset;
773 	kobject_init(&c->kobj, &bch2_fs_ktype);
774 	kobject_init(&c->internal, &bch2_fs_internal_ktype);
775 	kobject_init(&c->opts_dir, &bch2_fs_opts_dir_ktype);
776 	kobject_init(&c->time_stats, &bch2_fs_time_stats_ktype);
777 	kobject_init(&c->counters_kobj, &bch2_fs_counters_ktype);
778 
779 	c->minor		= -1;
780 	c->disk_sb.fs_sb	= true;
781 
782 	init_rwsem(&c->state_lock);
783 	mutex_init(&c->sb_lock);
784 	mutex_init(&c->replicas_gc_lock);
785 	mutex_init(&c->btree_root_lock);
786 	INIT_WORK(&c->read_only_work, bch2_fs_read_only_work);
787 
788 	refcount_set(&c->ro_ref, 1);
789 	init_waitqueue_head(&c->ro_ref_wait);
790 	spin_lock_init(&c->recovery_pass_lock);
791 	sema_init(&c->online_fsck_mutex, 1);
792 
793 	for (i = 0; i < BCH_TIME_STAT_NR; i++)
794 		bch2_time_stats_init(&c->times[i]);
795 
796 	bch2_fs_copygc_init(c);
797 	bch2_fs_btree_key_cache_init_early(&c->btree_key_cache);
798 	bch2_fs_btree_iter_init_early(c);
799 	bch2_fs_btree_interior_update_init_early(c);
800 	bch2_fs_journal_keys_init(c);
801 	bch2_fs_allocator_background_init(c);
802 	bch2_fs_allocator_foreground_init(c);
803 	bch2_fs_rebalance_init(c);
804 	bch2_fs_quota_init(c);
805 	bch2_fs_ec_init_early(c);
806 	bch2_fs_move_init(c);
807 	bch2_fs_sb_errors_init_early(c);
808 
809 	INIT_LIST_HEAD(&c->list);
810 
811 	mutex_init(&c->bio_bounce_pages_lock);
812 	mutex_init(&c->snapshot_table_lock);
813 	init_rwsem(&c->snapshot_create_lock);
814 
815 	spin_lock_init(&c->btree_write_error_lock);
816 
817 	INIT_LIST_HEAD(&c->journal_iters);
818 
819 	INIT_LIST_HEAD(&c->fsck_error_msgs);
820 	mutex_init(&c->fsck_error_msgs_lock);
821 
822 	seqcount_init(&c->usage_lock);
823 
824 	sema_init(&c->io_in_flight, 128);
825 
826 	INIT_LIST_HEAD(&c->vfs_inodes_list);
827 	mutex_init(&c->vfs_inodes_lock);
828 
829 	c->journal.flush_write_time	= &c->times[BCH_TIME_journal_flush_write];
830 	c->journal.noflush_write_time	= &c->times[BCH_TIME_journal_noflush_write];
831 	c->journal.flush_seq_time	= &c->times[BCH_TIME_journal_flush_seq];
832 
833 	bch2_fs_btree_cache_init_early(&c->btree_cache);
834 
835 	mutex_init(&c->sectors_available_lock);
836 
837 	ret = percpu_init_rwsem(&c->mark_lock);
838 	if (ret)
839 		goto err;
840 
841 	mutex_lock(&c->sb_lock);
842 	ret = bch2_sb_to_fs(c, sb);
843 	mutex_unlock(&c->sb_lock);
844 
845 	if (ret)
846 		goto err;
847 
848 #ifdef CONFIG_UNICODE
849 	/* Default encoding until we can potentially have more as an option. */
850 	c->cf_encoding = utf8_load(BCH_FS_DEFAULT_UTF8_ENCODING);
851 	if (IS_ERR(c->cf_encoding)) {
852 		printk(KERN_ERR "Cannot load UTF-8 encoding for filesystem. Version: %u.%u.%u",
853 			unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
854 			unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
855 			unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
856 		ret = -EINVAL;
857 		goto err;
858 	}
859 #else
860 	if (c->sb.features & BIT_ULL(BCH_FEATURE_casefolding)) {
861 		printk(KERN_ERR "Cannot mount a filesystem with casefolding on a kernel without CONFIG_UNICODE\n");
862 		ret = -EINVAL;
863 		goto err;
864 	}
865 #endif
866 
867 	pr_uuid(&name, c->sb.user_uuid.b);
868 	ret = name.allocation_failure ? -BCH_ERR_ENOMEM_fs_name_alloc : 0;
869 	if (ret)
870 		goto err;
871 
872 	strscpy(c->name, name.buf, sizeof(c->name));
873 	printbuf_exit(&name);
874 
875 	/* Compat: */
876 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
877 	    !BCH_SB_JOURNAL_FLUSH_DELAY(sb))
878 		SET_BCH_SB_JOURNAL_FLUSH_DELAY(sb, 1000);
879 
880 	if (le16_to_cpu(sb->version) <= bcachefs_metadata_version_inode_v2 &&
881 	    !BCH_SB_JOURNAL_RECLAIM_DELAY(sb))
882 		SET_BCH_SB_JOURNAL_RECLAIM_DELAY(sb, 100);
883 
884 	c->opts = bch2_opts_default;
885 	ret = bch2_opts_from_sb(&c->opts, sb);
886 	if (ret)
887 		goto err;
888 
889 	bch2_opts_apply(&c->opts, opts);
890 
891 	c->btree_key_cache_btrees |= 1U << BTREE_ID_alloc;
892 	if (c->opts.inodes_use_key_cache)
893 		c->btree_key_cache_btrees |= 1U << BTREE_ID_inodes;
894 	c->btree_key_cache_btrees |= 1U << BTREE_ID_logged_ops;
895 
896 	c->block_bits		= ilog2(block_sectors(c));
897 	c->btree_foreground_merge_threshold = BTREE_FOREGROUND_MERGE_THRESHOLD(c);
898 
899 	if (bch2_fs_init_fault("fs_alloc")) {
900 		bch_err(c, "fs_alloc fault injected");
901 		ret = -EFAULT;
902 		goto err;
903 	}
904 
905 	iter_size = sizeof(struct sort_iter) +
906 		(btree_blocks(c) + 1) * 2 *
907 		sizeof(struct sort_iter_set);
908 
909 	if (!(c->btree_update_wq = alloc_workqueue("bcachefs",
910 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_UNBOUND, 512)) ||
911 	    !(c->btree_io_complete_wq = alloc_workqueue("bcachefs_btree_io",
912 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
913 	    !(c->copygc_wq = alloc_workqueue("bcachefs_copygc",
914 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 1)) ||
915 	    !(c->btree_read_complete_wq = alloc_workqueue("bcachefs_btree_read_complete",
916 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 512)) ||
917 	    !(c->btree_write_submit_wq = alloc_workqueue("bcachefs_btree_write_sumit",
918 				WQ_HIGHPRI|WQ_FREEZABLE|WQ_MEM_RECLAIM, 1)) ||
919 	    !(c->write_ref_wq = alloc_workqueue("bcachefs_write_ref",
920 				WQ_FREEZABLE, 0)) ||
921 #ifndef BCH_WRITE_REF_DEBUG
922 	    percpu_ref_init(&c->writes, bch2_writes_disabled,
923 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
924 #endif
925 	    mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
926 	    bioset_init(&c->btree_bio, 1,
927 			max(offsetof(struct btree_read_bio, bio),
928 			    offsetof(struct btree_write_bio, wbio.bio)),
929 			BIOSET_NEED_BVECS) ||
930 	    !(c->pcpu = alloc_percpu(struct bch_fs_pcpu)) ||
931 	    !(c->usage = alloc_percpu(struct bch_fs_usage_base)) ||
932 	    !(c->online_reserved = alloc_percpu(u64)) ||
933 	    mempool_init_kvmalloc_pool(&c->btree_bounce_pool, 1,
934 				       c->opts.btree_node_size) ||
935 	    mempool_init_kmalloc_pool(&c->large_bkey_pool, 1, 2048)) {
936 		ret = -BCH_ERR_ENOMEM_fs_other_alloc;
937 		goto err;
938 	}
939 
940 	ret = bch2_fs_counters_init(c) ?:
941 	    bch2_fs_sb_errors_init(c) ?:
942 	    bch2_io_clock_init(&c->io_clock[READ]) ?:
943 	    bch2_io_clock_init(&c->io_clock[WRITE]) ?:
944 	    bch2_fs_journal_init(&c->journal) ?:
945 	    bch2_fs_btree_iter_init(c) ?:
946 	    bch2_fs_btree_cache_init(c) ?:
947 	    bch2_fs_btree_key_cache_init(&c->btree_key_cache) ?:
948 	    bch2_fs_btree_interior_update_init(c) ?:
949 	    bch2_fs_btree_gc_init(c) ?:
950 	    bch2_fs_buckets_waiting_for_journal_init(c) ?:
951 	    bch2_fs_btree_write_buffer_init(c) ?:
952 	    bch2_fs_subvolumes_init(c) ?:
953 	    bch2_fs_io_read_init(c) ?:
954 	    bch2_fs_io_write_init(c) ?:
955 	    bch2_fs_nocow_locking_init(c) ?:
956 	    bch2_fs_encryption_init(c) ?:
957 	    bch2_fs_compress_init(c) ?:
958 	    bch2_fs_ec_init(c) ?:
959 	    bch2_fs_vfs_init(c) ?:
960 	    bch2_fs_fsio_init(c) ?:
961 	    bch2_fs_fs_io_buffered_init(c) ?:
962 	    bch2_fs_fs_io_direct_init(c);
963 	if (ret)
964 		goto err;
965 
966 	for (i = 0; i < c->sb.nr_devices; i++) {
967 		if (!bch2_member_exists(c->disk_sb.sb, i))
968 			continue;
969 		ret = bch2_dev_alloc(c, i);
970 		if (ret)
971 			goto err;
972 	}
973 
974 	bch2_journal_entry_res_resize(&c->journal,
975 			&c->btree_root_journal_res,
976 			BTREE_ID_NR * (JSET_KEYS_U64s + BKEY_BTREE_PTR_U64s_MAX));
977 	bch2_journal_entry_res_resize(&c->journal,
978 			&c->clock_journal_res,
979 			(sizeof(struct jset_entry_clock) / sizeof(u64)) * 2);
980 
981 	mutex_lock(&bch_fs_list_lock);
982 	ret = bch2_fs_online(c);
983 	mutex_unlock(&bch_fs_list_lock);
984 
985 	if (ret)
986 		goto err;
987 out:
988 	return c;
989 err:
990 	bch2_fs_free(c);
991 	c = ERR_PTR(ret);
992 	goto out;
993 }
994 
995 noinline_for_stack
996 static void print_mount_opts(struct bch_fs *c)
997 {
998 	enum bch_opt_id i;
999 	struct printbuf p = PRINTBUF;
1000 	bool first = true;
1001 
1002 	prt_str(&p, "starting version ");
1003 	bch2_version_to_text(&p, c->sb.version);
1004 
1005 	if (c->opts.read_only) {
1006 		prt_str(&p, " opts=");
1007 		first = false;
1008 		prt_printf(&p, "ro");
1009 	}
1010 
1011 	for (i = 0; i < bch2_opts_nr; i++) {
1012 		const struct bch_option *opt = &bch2_opt_table[i];
1013 		u64 v = bch2_opt_get_by_id(&c->opts, i);
1014 
1015 		if (!(opt->flags & OPT_MOUNT))
1016 			continue;
1017 
1018 		if (v == bch2_opt_get_by_id(&bch2_opts_default, i))
1019 			continue;
1020 
1021 		prt_str(&p, first ? " opts=" : ",");
1022 		first = false;
1023 		bch2_opt_to_text(&p, c, c->disk_sb.sb, opt, v, OPT_SHOW_MOUNT_STYLE);
1024 	}
1025 
1026 	bch_info(c, "%s", p.buf);
1027 	printbuf_exit(&p);
1028 }
1029 
1030 int bch2_fs_start(struct bch_fs *c)
1031 {
1032 	time64_t now = ktime_get_real_seconds();
1033 	int ret = 0;
1034 
1035 	print_mount_opts(c);
1036 
1037 	down_write(&c->state_lock);
1038 	mutex_lock(&c->sb_lock);
1039 
1040 	BUG_ON(test_bit(BCH_FS_started, &c->flags));
1041 
1042 	if (!bch2_sb_field_get_minsize(&c->disk_sb, ext,
1043 			sizeof(struct bch_sb_field_ext) / sizeof(u64))) {
1044 		mutex_unlock(&c->sb_lock);
1045 		up_write(&c->state_lock);
1046 		ret = -BCH_ERR_ENOSPC_sb;
1047 		goto err;
1048 	}
1049 
1050 	ret = bch2_sb_members_v2_init(c);
1051 	if (ret) {
1052 		mutex_unlock(&c->sb_lock);
1053 		up_write(&c->state_lock);
1054 		goto err;
1055 	}
1056 
1057 	for_each_online_member(c, ca)
1058 		bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount = cpu_to_le64(now);
1059 
1060 	mutex_unlock(&c->sb_lock);
1061 
1062 	for_each_rw_member(c, ca)
1063 		bch2_dev_allocator_add(c, ca);
1064 	bch2_recalc_capacity(c);
1065 	up_write(&c->state_lock);
1066 
1067 	c->recovery_task = current;
1068 	ret = BCH_SB_INITIALIZED(c->disk_sb.sb)
1069 		? bch2_fs_recovery(c)
1070 		: bch2_fs_initialize(c);
1071 	c->recovery_task = NULL;
1072 
1073 	if (ret)
1074 		goto err;
1075 
1076 	ret = bch2_opts_check_may_set(c);
1077 	if (ret)
1078 		goto err;
1079 
1080 	if (bch2_fs_init_fault("fs_start")) {
1081 		ret = -BCH_ERR_injected_fs_start;
1082 		goto err;
1083 	}
1084 
1085 	set_bit(BCH_FS_started, &c->flags);
1086 	wake_up(&c->ro_ref_wait);
1087 
1088 	down_write(&c->state_lock);
1089 	if (c->opts.read_only) {
1090 		bch2_fs_read_only(c);
1091 	} else {
1092 		ret = !test_bit(BCH_FS_rw, &c->flags)
1093 			? bch2_fs_read_write(c)
1094 			: bch2_fs_read_write_late(c);
1095 	}
1096 	up_write(&c->state_lock);
1097 
1098 err:
1099 	if (ret)
1100 		bch_err_msg(c, ret, "starting filesystem");
1101 	else
1102 		bch_verbose(c, "done starting filesystem");
1103 	return ret;
1104 }
1105 
1106 static int bch2_dev_may_add(struct bch_sb *sb, struct bch_fs *c)
1107 {
1108 	struct bch_member m = bch2_sb_member_get(sb, sb->dev_idx);
1109 
1110 	if (le16_to_cpu(sb->block_size) != block_sectors(c))
1111 		return -BCH_ERR_mismatched_block_size;
1112 
1113 	if (le16_to_cpu(m.bucket_size) <
1114 	    BCH_SB_BTREE_NODE_SIZE(c->disk_sb.sb))
1115 		return -BCH_ERR_bucket_size_too_small;
1116 
1117 	return 0;
1118 }
1119 
1120 static int bch2_dev_in_fs(struct bch_sb_handle *fs,
1121 			  struct bch_sb_handle *sb,
1122 			  struct bch_opts *opts)
1123 {
1124 	if (fs == sb)
1125 		return 0;
1126 
1127 	if (!uuid_equal(&fs->sb->uuid, &sb->sb->uuid))
1128 		return -BCH_ERR_device_not_a_member_of_filesystem;
1129 
1130 	if (!bch2_member_exists(fs->sb, sb->sb->dev_idx))
1131 		return -BCH_ERR_device_has_been_removed;
1132 
1133 	if (fs->sb->block_size != sb->sb->block_size)
1134 		return -BCH_ERR_mismatched_block_size;
1135 
1136 	if (le16_to_cpu(fs->sb->version) < bcachefs_metadata_version_member_seq ||
1137 	    le16_to_cpu(sb->sb->version) < bcachefs_metadata_version_member_seq)
1138 		return 0;
1139 
1140 	if (fs->sb->seq == sb->sb->seq &&
1141 	    fs->sb->write_time != sb->sb->write_time) {
1142 		struct printbuf buf = PRINTBUF;
1143 
1144 		prt_str(&buf, "Split brain detected between ");
1145 		prt_bdevname(&buf, sb->bdev);
1146 		prt_str(&buf, " and ");
1147 		prt_bdevname(&buf, fs->bdev);
1148 		prt_char(&buf, ':');
1149 		prt_newline(&buf);
1150 		prt_printf(&buf, "seq=%llu but write_time different, got", le64_to_cpu(sb->sb->seq));
1151 		prt_newline(&buf);
1152 
1153 		prt_bdevname(&buf, fs->bdev);
1154 		prt_char(&buf, ' ');
1155 		bch2_prt_datetime(&buf, le64_to_cpu(fs->sb->write_time));
1156 		prt_newline(&buf);
1157 
1158 		prt_bdevname(&buf, sb->bdev);
1159 		prt_char(&buf, ' ');
1160 		bch2_prt_datetime(&buf, le64_to_cpu(sb->sb->write_time));
1161 		prt_newline(&buf);
1162 
1163 		if (!opts->no_splitbrain_check)
1164 			prt_printf(&buf, "Not using older sb");
1165 
1166 		pr_err("%s", buf.buf);
1167 		printbuf_exit(&buf);
1168 
1169 		if (!opts->no_splitbrain_check)
1170 			return -BCH_ERR_device_splitbrain;
1171 	}
1172 
1173 	struct bch_member m = bch2_sb_member_get(fs->sb, sb->sb->dev_idx);
1174 	u64 seq_from_fs		= le64_to_cpu(m.seq);
1175 	u64 seq_from_member	= le64_to_cpu(sb->sb->seq);
1176 
1177 	if (seq_from_fs && seq_from_fs < seq_from_member) {
1178 		struct printbuf buf = PRINTBUF;
1179 
1180 		prt_str(&buf, "Split brain detected between ");
1181 		prt_bdevname(&buf, sb->bdev);
1182 		prt_str(&buf, " and ");
1183 		prt_bdevname(&buf, fs->bdev);
1184 		prt_char(&buf, ':');
1185 		prt_newline(&buf);
1186 
1187 		prt_bdevname(&buf, fs->bdev);
1188 		prt_str(&buf, " believes seq of ");
1189 		prt_bdevname(&buf, sb->bdev);
1190 		prt_printf(&buf, " to be %llu, but ", seq_from_fs);
1191 		prt_bdevname(&buf, sb->bdev);
1192 		prt_printf(&buf, " has %llu\n", seq_from_member);
1193 
1194 		if (!opts->no_splitbrain_check) {
1195 			prt_str(&buf, "Not using ");
1196 			prt_bdevname(&buf, sb->bdev);
1197 		}
1198 
1199 		pr_err("%s", buf.buf);
1200 		printbuf_exit(&buf);
1201 
1202 		if (!opts->no_splitbrain_check)
1203 			return -BCH_ERR_device_splitbrain;
1204 	}
1205 
1206 	return 0;
1207 }
1208 
1209 /* Device startup/shutdown: */
1210 
1211 static void bch2_dev_io_ref_stop(struct bch_dev *ca, int rw)
1212 {
1213 	if (!percpu_ref_is_zero(&ca->io_ref[rw])) {
1214 		reinit_completion(&ca->io_ref_completion[rw]);
1215 		percpu_ref_kill(&ca->io_ref[rw]);
1216 		wait_for_completion(&ca->io_ref_completion[rw]);
1217 	}
1218 }
1219 
1220 static void bch2_dev_release(struct kobject *kobj)
1221 {
1222 	struct bch_dev *ca = container_of(kobj, struct bch_dev, kobj);
1223 
1224 	kfree(ca);
1225 }
1226 
1227 static void bch2_dev_free(struct bch_dev *ca)
1228 {
1229 	WARN_ON(!percpu_ref_is_zero(&ca->io_ref[WRITE]));
1230 	WARN_ON(!percpu_ref_is_zero(&ca->io_ref[READ]));
1231 
1232 	cancel_work_sync(&ca->io_error_work);
1233 
1234 	bch2_dev_unlink(ca);
1235 
1236 	if (ca->kobj.state_in_sysfs)
1237 		kobject_del(&ca->kobj);
1238 
1239 	bch2_free_super(&ca->disk_sb);
1240 	bch2_dev_allocator_background_exit(ca);
1241 	bch2_dev_journal_exit(ca);
1242 
1243 	free_percpu(ca->io_done);
1244 	bch2_dev_buckets_free(ca);
1245 	kfree(ca->sb_read_scratch);
1246 
1247 	bch2_time_stats_quantiles_exit(&ca->io_latency[WRITE]);
1248 	bch2_time_stats_quantiles_exit(&ca->io_latency[READ]);
1249 
1250 	percpu_ref_exit(&ca->io_ref[WRITE]);
1251 	percpu_ref_exit(&ca->io_ref[READ]);
1252 #ifndef CONFIG_BCACHEFS_DEBUG
1253 	percpu_ref_exit(&ca->ref);
1254 #endif
1255 	kobject_put(&ca->kobj);
1256 }
1257 
1258 static void __bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca)
1259 {
1260 
1261 	lockdep_assert_held(&c->state_lock);
1262 
1263 	if (percpu_ref_is_zero(&ca->io_ref[READ]))
1264 		return;
1265 
1266 	__bch2_dev_read_only(c, ca);
1267 
1268 	bch2_dev_io_ref_stop(ca, READ);
1269 
1270 	bch2_dev_unlink(ca);
1271 
1272 	bch2_free_super(&ca->disk_sb);
1273 	bch2_dev_journal_exit(ca);
1274 }
1275 
1276 #ifndef CONFIG_BCACHEFS_DEBUG
1277 static void bch2_dev_ref_complete(struct percpu_ref *ref)
1278 {
1279 	struct bch_dev *ca = container_of(ref, struct bch_dev, ref);
1280 
1281 	complete(&ca->ref_completion);
1282 }
1283 #endif
1284 
1285 static void bch2_dev_io_ref_read_complete(struct percpu_ref *ref)
1286 {
1287 	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref[READ]);
1288 
1289 	complete(&ca->io_ref_completion[READ]);
1290 }
1291 
1292 static void bch2_dev_io_ref_write_complete(struct percpu_ref *ref)
1293 {
1294 	struct bch_dev *ca = container_of(ref, struct bch_dev, io_ref[WRITE]);
1295 
1296 	complete(&ca->io_ref_completion[WRITE]);
1297 }
1298 
1299 static void bch2_dev_unlink(struct bch_dev *ca)
1300 {
1301 	struct kobject *b;
1302 
1303 	/*
1304 	 * This is racy w.r.t. the underlying block device being hot-removed,
1305 	 * which removes it from sysfs.
1306 	 *
1307 	 * It'd be lovely if we had a way to handle this race, but the sysfs
1308 	 * code doesn't appear to provide a good method and block/holder.c is
1309 	 * susceptible as well:
1310 	 */
1311 	if (ca->kobj.state_in_sysfs &&
1312 	    ca->disk_sb.bdev &&
1313 	    (b = bdev_kobj(ca->disk_sb.bdev))->state_in_sysfs) {
1314 		sysfs_remove_link(b, "bcachefs");
1315 		sysfs_remove_link(&ca->kobj, "block");
1316 	}
1317 }
1318 
1319 static int bch2_dev_sysfs_online(struct bch_fs *c, struct bch_dev *ca)
1320 {
1321 	int ret;
1322 
1323 	if (!c->kobj.state_in_sysfs)
1324 		return 0;
1325 
1326 	if (!ca->kobj.state_in_sysfs) {
1327 		ret =   kobject_add(&ca->kobj, &c->kobj, "dev-%u", ca->dev_idx) ?:
1328 			bch2_opts_create_sysfs_files(&ca->kobj, OPT_DEVICE);
1329 		if (ret)
1330 			return ret;
1331 	}
1332 
1333 	if (ca->disk_sb.bdev) {
1334 		struct kobject *block = bdev_kobj(ca->disk_sb.bdev);
1335 
1336 		ret = sysfs_create_link(block, &ca->kobj, "bcachefs");
1337 		if (ret)
1338 			return ret;
1339 
1340 		ret = sysfs_create_link(&ca->kobj, block, "block");
1341 		if (ret)
1342 			return ret;
1343 	}
1344 
1345 	return 0;
1346 }
1347 
1348 static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
1349 					struct bch_member *member)
1350 {
1351 	struct bch_dev *ca;
1352 	unsigned i;
1353 
1354 	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
1355 	if (!ca)
1356 		return NULL;
1357 
1358 	kobject_init(&ca->kobj, &bch2_dev_ktype);
1359 	init_completion(&ca->ref_completion);
1360 	init_completion(&ca->io_ref_completion[READ]);
1361 	init_completion(&ca->io_ref_completion[WRITE]);
1362 
1363 	INIT_WORK(&ca->io_error_work, bch2_io_error_work);
1364 
1365 	bch2_time_stats_quantiles_init(&ca->io_latency[READ]);
1366 	bch2_time_stats_quantiles_init(&ca->io_latency[WRITE]);
1367 
1368 	ca->mi = bch2_mi_to_cpu(member);
1369 
1370 	for (i = 0; i < ARRAY_SIZE(member->errors); i++)
1371 		atomic64_set(&ca->errors[i], le64_to_cpu(member->errors[i]));
1372 
1373 	ca->uuid = member->uuid;
1374 
1375 	ca->nr_btree_reserve = DIV_ROUND_UP(BTREE_NODE_RESERVE,
1376 			     ca->mi.bucket_size / btree_sectors(c));
1377 
1378 #ifndef CONFIG_BCACHEFS_DEBUG
1379 	if (percpu_ref_init(&ca->ref, bch2_dev_ref_complete, 0, GFP_KERNEL))
1380 		goto err;
1381 #else
1382 	atomic_long_set(&ca->ref, 1);
1383 #endif
1384 
1385 	bch2_dev_allocator_background_init(ca);
1386 
1387 	if (percpu_ref_init(&ca->io_ref[READ], bch2_dev_io_ref_read_complete,
1388 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
1389 	    percpu_ref_init(&ca->io_ref[WRITE], bch2_dev_io_ref_write_complete,
1390 			    PERCPU_REF_INIT_DEAD, GFP_KERNEL) ||
1391 	    !(ca->sb_read_scratch = kmalloc(BCH_SB_READ_SCRATCH_BUF_SIZE, GFP_KERNEL)) ||
1392 	    bch2_dev_buckets_alloc(c, ca) ||
1393 	    !(ca->io_done	= alloc_percpu(*ca->io_done)))
1394 		goto err;
1395 
1396 	return ca;
1397 err:
1398 	bch2_dev_free(ca);
1399 	return NULL;
1400 }
1401 
1402 static void bch2_dev_attach(struct bch_fs *c, struct bch_dev *ca,
1403 			    unsigned dev_idx)
1404 {
1405 	ca->dev_idx = dev_idx;
1406 	__set_bit(ca->dev_idx, ca->self.d);
1407 	scnprintf(ca->name, sizeof(ca->name), "dev-%u", dev_idx);
1408 
1409 	ca->fs = c;
1410 	rcu_assign_pointer(c->devs[ca->dev_idx], ca);
1411 
1412 	if (bch2_dev_sysfs_online(c, ca))
1413 		pr_warn("error creating sysfs objects");
1414 }
1415 
1416 static int bch2_dev_alloc(struct bch_fs *c, unsigned dev_idx)
1417 {
1418 	struct bch_member member = bch2_sb_member_get(c->disk_sb.sb, dev_idx);
1419 	struct bch_dev *ca = NULL;
1420 
1421 	if (bch2_fs_init_fault("dev_alloc"))
1422 		goto err;
1423 
1424 	ca = __bch2_dev_alloc(c, &member);
1425 	if (!ca)
1426 		goto err;
1427 
1428 	ca->fs = c;
1429 
1430 	bch2_dev_attach(c, ca, dev_idx);
1431 	return 0;
1432 err:
1433 	return -BCH_ERR_ENOMEM_dev_alloc;
1434 }
1435 
1436 static int __bch2_dev_attach_bdev(struct bch_dev *ca, struct bch_sb_handle *sb)
1437 {
1438 	unsigned ret;
1439 
1440 	if (bch2_dev_is_online(ca)) {
1441 		bch_err(ca, "already have device online in slot %u",
1442 			sb->sb->dev_idx);
1443 		return -BCH_ERR_device_already_online;
1444 	}
1445 
1446 	if (get_capacity(sb->bdev->bd_disk) <
1447 	    ca->mi.bucket_size * ca->mi.nbuckets) {
1448 		bch_err(ca, "cannot online: device too small");
1449 		return -BCH_ERR_device_size_too_small;
1450 	}
1451 
1452 	BUG_ON(!percpu_ref_is_zero(&ca->io_ref[READ]));
1453 	BUG_ON(!percpu_ref_is_zero(&ca->io_ref[WRITE]));
1454 
1455 	ret = bch2_dev_journal_init(ca, sb->sb);
1456 	if (ret)
1457 		return ret;
1458 
1459 	/* Commit: */
1460 	ca->disk_sb = *sb;
1461 	memset(sb, 0, sizeof(*sb));
1462 
1463 	/*
1464 	 * Stash pointer to the filesystem for blk_holder_ops - note that once
1465 	 * attached to a filesystem, we will always close the block device
1466 	 * before tearing down the filesystem object.
1467 	 */
1468 	ca->disk_sb.holder->c = ca->fs;
1469 
1470 	ca->dev = ca->disk_sb.bdev->bd_dev;
1471 
1472 	percpu_ref_reinit(&ca->io_ref[READ]);
1473 
1474 	return 0;
1475 }
1476 
1477 static int bch2_dev_attach_bdev(struct bch_fs *c, struct bch_sb_handle *sb)
1478 {
1479 	struct bch_dev *ca;
1480 	int ret;
1481 
1482 	lockdep_assert_held(&c->state_lock);
1483 
1484 	if (le64_to_cpu(sb->sb->seq) >
1485 	    le64_to_cpu(c->disk_sb.sb->seq))
1486 		bch2_sb_to_fs(c, sb->sb);
1487 
1488 	BUG_ON(!bch2_dev_exists(c, sb->sb->dev_idx));
1489 
1490 	ca = bch2_dev_locked(c, sb->sb->dev_idx);
1491 
1492 	ret = __bch2_dev_attach_bdev(ca, sb);
1493 	if (ret)
1494 		return ret;
1495 
1496 	bch2_dev_sysfs_online(c, ca);
1497 
1498 	struct printbuf name = PRINTBUF;
1499 	prt_bdevname(&name, ca->disk_sb.bdev);
1500 
1501 	if (c->sb.nr_devices == 1)
1502 		strscpy(c->name, name.buf, sizeof(c->name));
1503 	strscpy(ca->name, name.buf, sizeof(ca->name));
1504 
1505 	printbuf_exit(&name);
1506 
1507 	rebalance_wakeup(c);
1508 	return 0;
1509 }
1510 
1511 /* Device management: */
1512 
1513 /*
1514  * Note: this function is also used by the error paths - when a particular
1515  * device sees an error, we call it to determine whether we can just set the
1516  * device RO, or - if this function returns false - we'll set the whole
1517  * filesystem RO:
1518  *
1519  * XXX: maybe we should be more explicit about whether we're changing state
1520  * because we got an error or what have you?
1521  */
1522 bool bch2_dev_state_allowed(struct bch_fs *c, struct bch_dev *ca,
1523 			    enum bch_member_state new_state, int flags)
1524 {
1525 	struct bch_devs_mask new_online_devs;
1526 	int nr_rw = 0, required;
1527 
1528 	lockdep_assert_held(&c->state_lock);
1529 
1530 	switch (new_state) {
1531 	case BCH_MEMBER_STATE_rw:
1532 		return true;
1533 	case BCH_MEMBER_STATE_ro:
1534 		if (ca->mi.state != BCH_MEMBER_STATE_rw)
1535 			return true;
1536 
1537 		/* do we have enough devices to write to?  */
1538 		for_each_member_device(c, ca2)
1539 			if (ca2 != ca)
1540 				nr_rw += ca2->mi.state == BCH_MEMBER_STATE_rw;
1541 
1542 		required = max(!(flags & BCH_FORCE_IF_METADATA_DEGRADED)
1543 			       ? c->opts.metadata_replicas
1544 			       : metadata_replicas_required(c),
1545 			       !(flags & BCH_FORCE_IF_DATA_DEGRADED)
1546 			       ? c->opts.data_replicas
1547 			       : data_replicas_required(c));
1548 
1549 		return nr_rw >= required;
1550 	case BCH_MEMBER_STATE_failed:
1551 	case BCH_MEMBER_STATE_spare:
1552 		if (ca->mi.state != BCH_MEMBER_STATE_rw &&
1553 		    ca->mi.state != BCH_MEMBER_STATE_ro)
1554 			return true;
1555 
1556 		/* do we have enough devices to read from?  */
1557 		new_online_devs = bch2_online_devs(c);
1558 		__clear_bit(ca->dev_idx, new_online_devs.d);
1559 
1560 		return bch2_have_enough_devs(c, new_online_devs, flags, false);
1561 	default:
1562 		BUG();
1563 	}
1564 }
1565 
1566 static bool bch2_fs_may_start(struct bch_fs *c)
1567 {
1568 	struct bch_dev *ca;
1569 	unsigned i, flags = 0;
1570 
1571 	if (c->opts.very_degraded)
1572 		flags |= BCH_FORCE_IF_DEGRADED|BCH_FORCE_IF_LOST;
1573 
1574 	if (c->opts.degraded)
1575 		flags |= BCH_FORCE_IF_DEGRADED;
1576 
1577 	if (!c->opts.degraded &&
1578 	    !c->opts.very_degraded) {
1579 		mutex_lock(&c->sb_lock);
1580 
1581 		for (i = 0; i < c->disk_sb.sb->nr_devices; i++) {
1582 			if (!bch2_member_exists(c->disk_sb.sb, i))
1583 				continue;
1584 
1585 			ca = bch2_dev_locked(c, i);
1586 
1587 			if (!bch2_dev_is_online(ca) &&
1588 			    (ca->mi.state == BCH_MEMBER_STATE_rw ||
1589 			     ca->mi.state == BCH_MEMBER_STATE_ro)) {
1590 				mutex_unlock(&c->sb_lock);
1591 				return false;
1592 			}
1593 		}
1594 		mutex_unlock(&c->sb_lock);
1595 	}
1596 
1597 	return bch2_have_enough_devs(c, bch2_online_devs(c), flags, true);
1598 }
1599 
1600 static void __bch2_dev_read_only(struct bch_fs *c, struct bch_dev *ca)
1601 {
1602 	bch2_dev_io_ref_stop(ca, WRITE);
1603 
1604 	/*
1605 	 * The allocator thread itself allocates btree nodes, so stop it first:
1606 	 */
1607 	bch2_dev_allocator_remove(c, ca);
1608 	bch2_recalc_capacity(c);
1609 	bch2_dev_journal_stop(&c->journal, ca);
1610 }
1611 
1612 static void __bch2_dev_read_write(struct bch_fs *c, struct bch_dev *ca)
1613 {
1614 	lockdep_assert_held(&c->state_lock);
1615 
1616 	BUG_ON(ca->mi.state != BCH_MEMBER_STATE_rw);
1617 
1618 	bch2_dev_allocator_add(c, ca);
1619 	bch2_recalc_capacity(c);
1620 
1621 	if (percpu_ref_is_zero(&ca->io_ref[WRITE]))
1622 		percpu_ref_reinit(&ca->io_ref[WRITE]);
1623 
1624 	bch2_dev_do_discards(ca);
1625 }
1626 
1627 int __bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1628 			 enum bch_member_state new_state, int flags)
1629 {
1630 	struct bch_member *m;
1631 	int ret = 0;
1632 
1633 	if (ca->mi.state == new_state)
1634 		return 0;
1635 
1636 	if (!bch2_dev_state_allowed(c, ca, new_state, flags))
1637 		return -BCH_ERR_device_state_not_allowed;
1638 
1639 	if (new_state != BCH_MEMBER_STATE_rw)
1640 		__bch2_dev_read_only(c, ca);
1641 
1642 	bch_notice(ca, "%s", bch2_member_states[new_state]);
1643 
1644 	mutex_lock(&c->sb_lock);
1645 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
1646 	SET_BCH_MEMBER_STATE(m, new_state);
1647 	bch2_write_super(c);
1648 	mutex_unlock(&c->sb_lock);
1649 
1650 	if (new_state == BCH_MEMBER_STATE_rw)
1651 		__bch2_dev_read_write(c, ca);
1652 
1653 	rebalance_wakeup(c);
1654 
1655 	return ret;
1656 }
1657 
1658 int bch2_dev_set_state(struct bch_fs *c, struct bch_dev *ca,
1659 		       enum bch_member_state new_state, int flags)
1660 {
1661 	int ret;
1662 
1663 	down_write(&c->state_lock);
1664 	ret = __bch2_dev_set_state(c, ca, new_state, flags);
1665 	up_write(&c->state_lock);
1666 
1667 	return ret;
1668 }
1669 
1670 /* Device add/removal: */
1671 
1672 int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
1673 {
1674 	struct bch_member *m;
1675 	unsigned dev_idx = ca->dev_idx, data;
1676 	int ret;
1677 
1678 	down_write(&c->state_lock);
1679 
1680 	/*
1681 	 * We consume a reference to ca->ref, regardless of whether we succeed
1682 	 * or fail:
1683 	 */
1684 	bch2_dev_put(ca);
1685 
1686 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1687 		bch_err(ca, "Cannot remove without losing data");
1688 		ret = -BCH_ERR_device_state_not_allowed;
1689 		goto err;
1690 	}
1691 
1692 	__bch2_dev_read_only(c, ca);
1693 
1694 	ret = bch2_dev_data_drop(c, ca->dev_idx, flags);
1695 	bch_err_msg(ca, ret, "bch2_dev_data_drop()");
1696 	if (ret)
1697 		goto err;
1698 
1699 	ret = bch2_dev_remove_alloc(c, ca);
1700 	bch_err_msg(ca, ret, "bch2_dev_remove_alloc()");
1701 	if (ret)
1702 		goto err;
1703 
1704 	/*
1705 	 * We need to flush the entire journal to get rid of keys that reference
1706 	 * the device being removed before removing the superblock entry
1707 	 */
1708 	bch2_journal_flush_all_pins(&c->journal);
1709 
1710 	/*
1711 	 * this is really just needed for the bch2_replicas_gc_(start|end)
1712 	 * calls, and could be cleaned up:
1713 	 */
1714 	ret = bch2_journal_flush_device_pins(&c->journal, ca->dev_idx);
1715 	bch_err_msg(ca, ret, "bch2_journal_flush_device_pins()");
1716 	if (ret)
1717 		goto err;
1718 
1719 	ret = bch2_journal_flush(&c->journal);
1720 	bch_err_msg(ca, ret, "bch2_journal_flush()");
1721 	if (ret)
1722 		goto err;
1723 
1724 	ret = bch2_replicas_gc2(c);
1725 	bch_err_msg(ca, ret, "bch2_replicas_gc2()");
1726 	if (ret)
1727 		goto err;
1728 
1729 	data = bch2_dev_has_data(c, ca);
1730 	if (data) {
1731 		struct printbuf data_has = PRINTBUF;
1732 
1733 		prt_bitflags(&data_has, __bch2_data_types, data);
1734 		bch_err(ca, "Remove failed, still has data (%s)", data_has.buf);
1735 		printbuf_exit(&data_has);
1736 		ret = -EBUSY;
1737 		goto err;
1738 	}
1739 
1740 	__bch2_dev_offline(c, ca);
1741 
1742 	mutex_lock(&c->sb_lock);
1743 	rcu_assign_pointer(c->devs[ca->dev_idx], NULL);
1744 	mutex_unlock(&c->sb_lock);
1745 
1746 #ifndef CONFIG_BCACHEFS_DEBUG
1747 	percpu_ref_kill(&ca->ref);
1748 #else
1749 	ca->dying = true;
1750 	bch2_dev_put(ca);
1751 #endif
1752 	wait_for_completion(&ca->ref_completion);
1753 
1754 	bch2_dev_free(ca);
1755 
1756 	/*
1757 	 * Free this device's slot in the bch_member array - all pointers to
1758 	 * this device must be gone:
1759 	 */
1760 	mutex_lock(&c->sb_lock);
1761 	m = bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx);
1762 	memset(&m->uuid, 0, sizeof(m->uuid));
1763 
1764 	bch2_write_super(c);
1765 
1766 	mutex_unlock(&c->sb_lock);
1767 	up_write(&c->state_lock);
1768 	return 0;
1769 err:
1770 	if (ca->mi.state == BCH_MEMBER_STATE_rw &&
1771 	    !percpu_ref_is_zero(&ca->io_ref[READ]))
1772 		__bch2_dev_read_write(c, ca);
1773 	up_write(&c->state_lock);
1774 	return ret;
1775 }
1776 
1777 /* Add new device to running filesystem: */
1778 int bch2_dev_add(struct bch_fs *c, const char *path)
1779 {
1780 	struct bch_opts opts = bch2_opts_empty();
1781 	struct bch_sb_handle sb;
1782 	struct bch_dev *ca = NULL;
1783 	struct printbuf errbuf = PRINTBUF;
1784 	struct printbuf label = PRINTBUF;
1785 	int ret;
1786 
1787 	ret = bch2_read_super(path, &opts, &sb);
1788 	bch_err_msg(c, ret, "reading super");
1789 	if (ret)
1790 		goto err;
1791 
1792 	struct bch_member dev_mi = bch2_sb_member_get(sb.sb, sb.sb->dev_idx);
1793 
1794 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1795 		bch2_disk_path_to_text_sb(&label, sb.sb, BCH_MEMBER_GROUP(&dev_mi) - 1);
1796 		if (label.allocation_failure) {
1797 			ret = -ENOMEM;
1798 			goto err;
1799 		}
1800 	}
1801 
1802 	ret = bch2_dev_may_add(sb.sb, c);
1803 	if (ret)
1804 		goto err;
1805 
1806 	ca = __bch2_dev_alloc(c, &dev_mi);
1807 	if (!ca) {
1808 		ret = -ENOMEM;
1809 		goto err;
1810 	}
1811 
1812 	ret = __bch2_dev_attach_bdev(ca, &sb);
1813 	if (ret)
1814 		goto err;
1815 
1816 	down_write(&c->state_lock);
1817 	mutex_lock(&c->sb_lock);
1818 
1819 	ret = bch2_sb_from_fs(c, ca);
1820 	bch_err_msg(c, ret, "setting up new superblock");
1821 	if (ret)
1822 		goto err_unlock;
1823 
1824 	if (dynamic_fault("bcachefs:add:no_slot"))
1825 		goto err_unlock;
1826 
1827 	ret = bch2_sb_member_alloc(c);
1828 	if (ret < 0) {
1829 		bch_err_msg(c, ret, "setting up new superblock");
1830 		goto err_unlock;
1831 	}
1832 	unsigned dev_idx = ret;
1833 
1834 	/* success: */
1835 
1836 	dev_mi.last_mount = cpu_to_le64(ktime_get_real_seconds());
1837 	*bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx) = dev_mi;
1838 
1839 	ca->disk_sb.sb->dev_idx	= dev_idx;
1840 	bch2_dev_attach(c, ca, dev_idx);
1841 
1842 	if (BCH_MEMBER_GROUP(&dev_mi)) {
1843 		ret = __bch2_dev_group_set(c, ca, label.buf);
1844 		bch_err_msg(c, ret, "creating new label");
1845 		if (ret)
1846 			goto err_unlock;
1847 	}
1848 
1849 	bch2_write_super(c);
1850 	mutex_unlock(&c->sb_lock);
1851 
1852 	ret = bch2_dev_usage_init(ca, false);
1853 	if (ret)
1854 		goto err_late;
1855 
1856 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1857 	bch_err_msg(ca, ret, "marking new superblock");
1858 	if (ret)
1859 		goto err_late;
1860 
1861 	ret = bch2_fs_freespace_init(c);
1862 	bch_err_msg(ca, ret, "initializing free space");
1863 	if (ret)
1864 		goto err_late;
1865 
1866 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1867 		__bch2_dev_read_write(c, ca);
1868 
1869 	ret = bch2_dev_journal_alloc(ca, false);
1870 	bch_err_msg(c, ret, "allocating journal");
1871 	if (ret)
1872 		goto err_late;
1873 
1874 	up_write(&c->state_lock);
1875 out:
1876 	printbuf_exit(&label);
1877 	printbuf_exit(&errbuf);
1878 	bch_err_fn(c, ret);
1879 	return ret;
1880 
1881 err_unlock:
1882 	mutex_unlock(&c->sb_lock);
1883 	up_write(&c->state_lock);
1884 err:
1885 	if (ca)
1886 		bch2_dev_free(ca);
1887 	bch2_free_super(&sb);
1888 	goto out;
1889 err_late:
1890 	up_write(&c->state_lock);
1891 	ca = NULL;
1892 	goto err;
1893 }
1894 
1895 /* Hot add existing device to running filesystem: */
1896 int bch2_dev_online(struct bch_fs *c, const char *path)
1897 {
1898 	struct bch_opts opts = bch2_opts_empty();
1899 	struct bch_sb_handle sb = { NULL };
1900 	struct bch_dev *ca;
1901 	unsigned dev_idx;
1902 	int ret;
1903 
1904 	down_write(&c->state_lock);
1905 
1906 	ret = bch2_read_super(path, &opts, &sb);
1907 	if (ret) {
1908 		up_write(&c->state_lock);
1909 		return ret;
1910 	}
1911 
1912 	dev_idx = sb.sb->dev_idx;
1913 
1914 	ret = bch2_dev_in_fs(&c->disk_sb, &sb, &c->opts);
1915 	bch_err_msg(c, ret, "bringing %s online", path);
1916 	if (ret)
1917 		goto err;
1918 
1919 	ret = bch2_dev_attach_bdev(c, &sb);
1920 	if (ret)
1921 		goto err;
1922 
1923 	ca = bch2_dev_locked(c, dev_idx);
1924 
1925 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
1926 	bch_err_msg(c, ret, "bringing %s online: error from bch2_trans_mark_dev_sb", path);
1927 	if (ret)
1928 		goto err;
1929 
1930 	if (ca->mi.state == BCH_MEMBER_STATE_rw)
1931 		__bch2_dev_read_write(c, ca);
1932 
1933 	if (!ca->mi.freespace_initialized) {
1934 		ret = bch2_dev_freespace_init(c, ca, 0, ca->mi.nbuckets);
1935 		bch_err_msg(ca, ret, "initializing free space");
1936 		if (ret)
1937 			goto err;
1938 	}
1939 
1940 	if (!ca->journal.nr) {
1941 		ret = bch2_dev_journal_alloc(ca, false);
1942 		bch_err_msg(ca, ret, "allocating journal");
1943 		if (ret)
1944 			goto err;
1945 	}
1946 
1947 	mutex_lock(&c->sb_lock);
1948 	bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx)->last_mount =
1949 		cpu_to_le64(ktime_get_real_seconds());
1950 	bch2_write_super(c);
1951 	mutex_unlock(&c->sb_lock);
1952 
1953 	up_write(&c->state_lock);
1954 	return 0;
1955 err:
1956 	up_write(&c->state_lock);
1957 	bch2_free_super(&sb);
1958 	return ret;
1959 }
1960 
1961 int bch2_dev_offline(struct bch_fs *c, struct bch_dev *ca, int flags)
1962 {
1963 	down_write(&c->state_lock);
1964 
1965 	if (!bch2_dev_is_online(ca)) {
1966 		bch_err(ca, "Already offline");
1967 		up_write(&c->state_lock);
1968 		return 0;
1969 	}
1970 
1971 	if (!bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, flags)) {
1972 		bch_err(ca, "Cannot offline required disk");
1973 		up_write(&c->state_lock);
1974 		return -BCH_ERR_device_state_not_allowed;
1975 	}
1976 
1977 	__bch2_dev_offline(c, ca);
1978 
1979 	up_write(&c->state_lock);
1980 	return 0;
1981 }
1982 
1983 int bch2_dev_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
1984 {
1985 	struct bch_member *m;
1986 	u64 old_nbuckets;
1987 	int ret = 0;
1988 
1989 	down_write(&c->state_lock);
1990 	old_nbuckets = ca->mi.nbuckets;
1991 
1992 	if (nbuckets < ca->mi.nbuckets) {
1993 		bch_err(ca, "Cannot shrink yet");
1994 		ret = -EINVAL;
1995 		goto err;
1996 	}
1997 
1998 	if (nbuckets > BCH_MEMBER_NBUCKETS_MAX) {
1999 		bch_err(ca, "New device size too big (%llu greater than max %u)",
2000 			nbuckets, BCH_MEMBER_NBUCKETS_MAX);
2001 		ret = -BCH_ERR_device_size_too_big;
2002 		goto err;
2003 	}
2004 
2005 	if (bch2_dev_is_online(ca) &&
2006 	    get_capacity(ca->disk_sb.bdev->bd_disk) <
2007 	    ca->mi.bucket_size * nbuckets) {
2008 		bch_err(ca, "New size larger than device");
2009 		ret = -BCH_ERR_device_size_too_small;
2010 		goto err;
2011 	}
2012 
2013 	ret = bch2_dev_buckets_resize(c, ca, nbuckets);
2014 	bch_err_msg(ca, ret, "resizing buckets");
2015 	if (ret)
2016 		goto err;
2017 
2018 	ret = bch2_trans_mark_dev_sb(c, ca, BTREE_TRIGGER_transactional);
2019 	if (ret)
2020 		goto err;
2021 
2022 	mutex_lock(&c->sb_lock);
2023 	m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
2024 	m->nbuckets = cpu_to_le64(nbuckets);
2025 
2026 	bch2_write_super(c);
2027 	mutex_unlock(&c->sb_lock);
2028 
2029 	if (ca->mi.freespace_initialized) {
2030 		u64 v[3] = { nbuckets - old_nbuckets, 0, 0 };
2031 
2032 		ret   = bch2_trans_commit_do(ca->fs, NULL, NULL, 0,
2033 				bch2_disk_accounting_mod2(trans, false, v, dev_data_type,
2034 							  .dev = ca->dev_idx,
2035 							  .data_type = BCH_DATA_free)) ?:
2036 			bch2_dev_freespace_init(c, ca, old_nbuckets, nbuckets);
2037 		if (ret)
2038 			goto err;
2039 	}
2040 
2041 	bch2_recalc_capacity(c);
2042 err:
2043 	up_write(&c->state_lock);
2044 	return ret;
2045 }
2046 
2047 /* return with ref on ca->ref: */
2048 struct bch_dev *bch2_dev_lookup(struct bch_fs *c, const char *name)
2049 {
2050 	if (!strncmp(name, "/dev/", strlen("/dev/")))
2051 		name += strlen("/dev/");
2052 
2053 	for_each_member_device(c, ca)
2054 		if (!strcmp(name, ca->name))
2055 			return ca;
2056 	return ERR_PTR(-BCH_ERR_ENOENT_dev_not_found);
2057 }
2058 
2059 /* blk_holder_ops: */
2060 
2061 static struct bch_fs *bdev_get_fs(struct block_device *bdev)
2062 	__releases(&bdev->bd_holder_lock)
2063 {
2064 	struct bch_sb_handle_holder *holder = bdev->bd_holder;
2065 	struct bch_fs *c = holder->c;
2066 
2067 	if (c && !bch2_ro_ref_tryget(c))
2068 		c = NULL;
2069 
2070 	mutex_unlock(&bdev->bd_holder_lock);
2071 
2072 	if (c)
2073 		wait_event(c->ro_ref_wait, test_bit(BCH_FS_started, &c->flags));
2074 	return c;
2075 }
2076 
2077 /* returns with ref on ca->ref */
2078 static struct bch_dev *bdev_to_bch_dev(struct bch_fs *c, struct block_device *bdev)
2079 {
2080 	for_each_member_device(c, ca)
2081 		if (ca->disk_sb.bdev == bdev)
2082 			return ca;
2083 	return NULL;
2084 }
2085 
2086 static void bch2_fs_bdev_mark_dead(struct block_device *bdev, bool surprise)
2087 {
2088 	struct bch_fs *c = bdev_get_fs(bdev);
2089 	if (!c)
2090 		return;
2091 
2092 	struct super_block *sb = c->vfs_sb;
2093 	if (sb) {
2094 		/*
2095 		 * Not necessary, c->ro_ref guards against the filesystem being
2096 		 * unmounted - we only take this to avoid a warning in
2097 		 * sync_filesystem:
2098 		 */
2099 		down_read(&sb->s_umount);
2100 	}
2101 
2102 	down_write(&c->state_lock);
2103 	struct bch_dev *ca = bdev_to_bch_dev(c, bdev);
2104 	if (!ca)
2105 		goto unlock;
2106 
2107 	if (bch2_dev_state_allowed(c, ca, BCH_MEMBER_STATE_failed, BCH_FORCE_IF_DEGRADED)) {
2108 		__bch2_dev_offline(c, ca);
2109 	} else {
2110 		if (sb) {
2111 			if (!surprise)
2112 				sync_filesystem(sb);
2113 			shrink_dcache_sb(sb);
2114 			evict_inodes(sb);
2115 		}
2116 
2117 		bch2_journal_flush(&c->journal);
2118 		bch2_fs_emergency_read_only(c);
2119 	}
2120 
2121 	bch2_dev_put(ca);
2122 unlock:
2123 	if (sb)
2124 		up_read(&sb->s_umount);
2125 	up_write(&c->state_lock);
2126 	bch2_ro_ref_put(c);
2127 }
2128 
2129 static void bch2_fs_bdev_sync(struct block_device *bdev)
2130 {
2131 	struct bch_fs *c = bdev_get_fs(bdev);
2132 	if (!c)
2133 		return;
2134 
2135 	struct super_block *sb = c->vfs_sb;
2136 	if (sb) {
2137 		/*
2138 		 * Not necessary, c->ro_ref guards against the filesystem being
2139 		 * unmounted - we only take this to avoid a warning in
2140 		 * sync_filesystem:
2141 		 */
2142 		down_read(&sb->s_umount);
2143 		sync_filesystem(sb);
2144 		up_read(&sb->s_umount);
2145 	}
2146 
2147 	bch2_ro_ref_put(c);
2148 }
2149 
2150 const struct blk_holder_ops bch2_sb_handle_bdev_ops = {
2151 	.mark_dead		= bch2_fs_bdev_mark_dead,
2152 	.sync			= bch2_fs_bdev_sync,
2153 };
2154 
2155 /* Filesystem open: */
2156 
2157 static inline int sb_cmp(struct bch_sb *l, struct bch_sb *r)
2158 {
2159 	return  cmp_int(le64_to_cpu(l->seq), le64_to_cpu(r->seq)) ?:
2160 		cmp_int(le64_to_cpu(l->write_time), le64_to_cpu(r->write_time));
2161 }
2162 
2163 struct bch_fs *bch2_fs_open(char * const *devices, unsigned nr_devices,
2164 			    struct bch_opts opts)
2165 {
2166 	DARRAY(struct bch_sb_handle) sbs = { 0 };
2167 	struct bch_fs *c = NULL;
2168 	struct bch_sb_handle *best = NULL;
2169 	struct printbuf errbuf = PRINTBUF;
2170 	int ret = 0;
2171 
2172 	if (!try_module_get(THIS_MODULE))
2173 		return ERR_PTR(-ENODEV);
2174 
2175 	if (!nr_devices) {
2176 		ret = -EINVAL;
2177 		goto err;
2178 	}
2179 
2180 	ret = darray_make_room(&sbs, nr_devices);
2181 	if (ret)
2182 		goto err;
2183 
2184 	for (unsigned i = 0; i < nr_devices; i++) {
2185 		struct bch_sb_handle sb = { NULL };
2186 
2187 		ret = bch2_read_super(devices[i], &opts, &sb);
2188 		if (ret)
2189 			goto err;
2190 
2191 		BUG_ON(darray_push(&sbs, sb));
2192 	}
2193 
2194 	if (opts.nochanges && !opts.read_only) {
2195 		ret = -BCH_ERR_erofs_nochanges;
2196 		goto err_print;
2197 	}
2198 
2199 	darray_for_each(sbs, sb)
2200 		if (!best || sb_cmp(sb->sb, best->sb) > 0)
2201 			best = sb;
2202 
2203 	darray_for_each_reverse(sbs, sb) {
2204 		ret = bch2_dev_in_fs(best, sb, &opts);
2205 
2206 		if (ret == -BCH_ERR_device_has_been_removed ||
2207 		    ret == -BCH_ERR_device_splitbrain) {
2208 			bch2_free_super(sb);
2209 			darray_remove_item(&sbs, sb);
2210 			best -= best > sb;
2211 			ret = 0;
2212 			continue;
2213 		}
2214 
2215 		if (ret)
2216 			goto err_print;
2217 	}
2218 
2219 	c = bch2_fs_alloc(best->sb, opts);
2220 	ret = PTR_ERR_OR_ZERO(c);
2221 	if (ret)
2222 		goto err;
2223 
2224 	down_write(&c->state_lock);
2225 	darray_for_each(sbs, sb) {
2226 		ret = bch2_dev_attach_bdev(c, sb);
2227 		if (ret) {
2228 			up_write(&c->state_lock);
2229 			goto err;
2230 		}
2231 	}
2232 	up_write(&c->state_lock);
2233 
2234 	if (!bch2_fs_may_start(c)) {
2235 		ret = -BCH_ERR_insufficient_devices_to_start;
2236 		goto err_print;
2237 	}
2238 
2239 	if (!c->opts.nostart) {
2240 		ret = bch2_fs_start(c);
2241 		if (ret)
2242 			goto err;
2243 	}
2244 out:
2245 	darray_for_each(sbs, sb)
2246 		bch2_free_super(sb);
2247 	darray_exit(&sbs);
2248 	printbuf_exit(&errbuf);
2249 	module_put(THIS_MODULE);
2250 	return c;
2251 err_print:
2252 	pr_err("bch_fs_open err opening %s: %s",
2253 	       devices[0], bch2_err_str(ret));
2254 err:
2255 	if (!IS_ERR_OR_NULL(c))
2256 		bch2_fs_stop(c);
2257 	c = ERR_PTR(ret);
2258 	goto out;
2259 }
2260 
2261 /* Global interfaces/init */
2262 
2263 static void bcachefs_exit(void)
2264 {
2265 	bch2_debug_exit();
2266 	bch2_vfs_exit();
2267 	bch2_chardev_exit();
2268 	bch2_btree_key_cache_exit();
2269 	if (bcachefs_kset)
2270 		kset_unregister(bcachefs_kset);
2271 }
2272 
2273 static int __init bcachefs_init(void)
2274 {
2275 	bch2_bkey_pack_test();
2276 
2277 	if (!(bcachefs_kset = kset_create_and_add("bcachefs", NULL, fs_kobj)) ||
2278 	    bch2_btree_key_cache_init() ||
2279 	    bch2_chardev_init() ||
2280 	    bch2_vfs_init() ||
2281 	    bch2_debug_init())
2282 		goto err;
2283 
2284 	return 0;
2285 err:
2286 	bcachefs_exit();
2287 	return -ENOMEM;
2288 }
2289 
2290 #define BCH_DEBUG_PARAM(name, description)			\
2291 	bool bch2_##name;					\
2292 	module_param_named(name, bch2_##name, bool, 0644);	\
2293 	MODULE_PARM_DESC(name, description);
2294 BCH_DEBUG_PARAMS()
2295 #undef BCH_DEBUG_PARAM
2296 
2297 __maybe_unused
2298 static unsigned bch2_metadata_version = bcachefs_metadata_version_current;
2299 module_param_named(version, bch2_metadata_version, uint, 0444);
2300 
2301 module_exit(bcachefs_exit);
2302 module_init(bcachefs_init);
2303