xref: /linux/fs/xfs/xfs_mount.c (revision e814f3fd16acfb7f9966773953de8f740a1e3202)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4  * All Rights Reserved.
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_bit.h"
13 #include "xfs_sb.h"
14 #include "xfs_mount.h"
15 #include "xfs_inode.h"
16 #include "xfs_dir2.h"
17 #include "xfs_ialloc.h"
18 #include "xfs_alloc.h"
19 #include "xfs_rtalloc.h"
20 #include "xfs_bmap.h"
21 #include "xfs_trans.h"
22 #include "xfs_trans_priv.h"
23 #include "xfs_log.h"
24 #include "xfs_log_priv.h"
25 #include "xfs_error.h"
26 #include "xfs_quota.h"
27 #include "xfs_fsops.h"
28 #include "xfs_icache.h"
29 #include "xfs_sysfs.h"
30 #include "xfs_rmap_btree.h"
31 #include "xfs_refcount_btree.h"
32 #include "xfs_reflink.h"
33 #include "xfs_extent_busy.h"
34 #include "xfs_health.h"
35 #include "xfs_trace.h"
36 #include "xfs_ag.h"
37 #include "xfs_rtbitmap.h"
38 #include "xfs_metafile.h"
39 #include "xfs_rtgroup.h"
40 #include "xfs_rtrmap_btree.h"
41 #include "xfs_rtrefcount_btree.h"
42 #include "scrub/stats.h"
43 
44 static DEFINE_MUTEX(xfs_uuid_table_mutex);
45 static int xfs_uuid_table_size;
46 static uuid_t *xfs_uuid_table;
47 
48 void
49 xfs_uuid_table_free(void)
50 {
51 	if (xfs_uuid_table_size == 0)
52 		return;
53 	kfree(xfs_uuid_table);
54 	xfs_uuid_table = NULL;
55 	xfs_uuid_table_size = 0;
56 }
57 
58 /*
59  * See if the UUID is unique among mounted XFS filesystems.
60  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
61  */
62 STATIC int
63 xfs_uuid_mount(
64 	struct xfs_mount	*mp)
65 {
66 	uuid_t			*uuid = &mp->m_sb.sb_uuid;
67 	int			hole, i;
68 
69 	/* Publish UUID in struct super_block */
70 	super_set_uuid(mp->m_super, uuid->b, sizeof(*uuid));
71 
72 	if (xfs_has_nouuid(mp))
73 		return 0;
74 
75 	if (uuid_is_null(uuid)) {
76 		xfs_warn(mp, "Filesystem has null UUID - can't mount");
77 		return -EINVAL;
78 	}
79 
80 	mutex_lock(&xfs_uuid_table_mutex);
81 	for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
82 		if (uuid_is_null(&xfs_uuid_table[i])) {
83 			hole = i;
84 			continue;
85 		}
86 		if (uuid_equal(uuid, &xfs_uuid_table[i]))
87 			goto out_duplicate;
88 	}
89 
90 	if (hole < 0) {
91 		xfs_uuid_table = krealloc(xfs_uuid_table,
92 			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
93 			GFP_KERNEL | __GFP_NOFAIL);
94 		hole = xfs_uuid_table_size++;
95 	}
96 	xfs_uuid_table[hole] = *uuid;
97 	mutex_unlock(&xfs_uuid_table_mutex);
98 
99 	return 0;
100 
101  out_duplicate:
102 	mutex_unlock(&xfs_uuid_table_mutex);
103 	xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
104 	return -EINVAL;
105 }
106 
107 STATIC void
108 xfs_uuid_unmount(
109 	struct xfs_mount	*mp)
110 {
111 	uuid_t			*uuid = &mp->m_sb.sb_uuid;
112 	int			i;
113 
114 	if (xfs_has_nouuid(mp))
115 		return;
116 
117 	mutex_lock(&xfs_uuid_table_mutex);
118 	for (i = 0; i < xfs_uuid_table_size; i++) {
119 		if (uuid_is_null(&xfs_uuid_table[i]))
120 			continue;
121 		if (!uuid_equal(uuid, &xfs_uuid_table[i]))
122 			continue;
123 		memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
124 		break;
125 	}
126 	ASSERT(i < xfs_uuid_table_size);
127 	mutex_unlock(&xfs_uuid_table_mutex);
128 }
129 
130 /*
131  * Check size of device based on the (data/realtime) block count.
132  * Note: this check is used by the growfs code as well as mount.
133  */
134 int
135 xfs_sb_validate_fsb_count(
136 	xfs_sb_t	*sbp,
137 	uint64_t	nblocks)
138 {
139 	uint64_t		max_bytes;
140 
141 	ASSERT(sbp->sb_blocklog >= BBSHIFT);
142 
143 	if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
144 		return -EFBIG;
145 
146 	/* Limited by ULONG_MAX of page cache index */
147 	if (max_bytes >> PAGE_SHIFT > ULONG_MAX)
148 		return -EFBIG;
149 	return 0;
150 }
151 
152 /*
153  * xfs_readsb
154  *
155  * Does the initial read of the superblock.
156  */
157 int
158 xfs_readsb(
159 	struct xfs_mount *mp,
160 	int		flags)
161 {
162 	unsigned int	sector_size;
163 	struct xfs_buf	*bp;
164 	struct xfs_sb	*sbp = &mp->m_sb;
165 	int		error;
166 	int		loud = !(flags & XFS_MFSI_QUIET);
167 	const struct xfs_buf_ops *buf_ops;
168 
169 	ASSERT(mp->m_sb_bp == NULL);
170 	ASSERT(mp->m_ddev_targp != NULL);
171 
172 	/*
173 	 * For the initial read, we must guess at the sector
174 	 * size based on the block device.  It's enough to
175 	 * get the sb_sectsize out of the superblock and
176 	 * then reread with the proper length.
177 	 * We don't verify it yet, because it may not be complete.
178 	 */
179 	sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
180 	buf_ops = NULL;
181 
182 	/*
183 	 * Allocate a (locked) buffer to hold the superblock. This will be kept
184 	 * around at all times to optimize access to the superblock. Therefore,
185 	 * set XBF_NO_IOACCT to make sure it doesn't hold the buftarg count
186 	 * elevated.
187 	 */
188 reread:
189 	error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
190 				      BTOBB(sector_size), XBF_NO_IOACCT, &bp,
191 				      buf_ops);
192 	if (error) {
193 		if (loud)
194 			xfs_warn(mp, "SB validate failed with error %d.", error);
195 		/* bad CRC means corrupted metadata */
196 		if (error == -EFSBADCRC)
197 			error = -EFSCORRUPTED;
198 		return error;
199 	}
200 
201 	/*
202 	 * Initialize the mount structure from the superblock.
203 	 */
204 	xfs_sb_from_disk(sbp, bp->b_addr);
205 
206 	/*
207 	 * If we haven't validated the superblock, do so now before we try
208 	 * to check the sector size and reread the superblock appropriately.
209 	 */
210 	if (sbp->sb_magicnum != XFS_SB_MAGIC) {
211 		if (loud)
212 			xfs_warn(mp, "Invalid superblock magic number");
213 		error = -EINVAL;
214 		goto release_buf;
215 	}
216 
217 	/*
218 	 * We must be able to do sector-sized and sector-aligned IO.
219 	 */
220 	if (sector_size > sbp->sb_sectsize) {
221 		if (loud)
222 			xfs_warn(mp, "device supports %u byte sectors (not %u)",
223 				sector_size, sbp->sb_sectsize);
224 		error = -ENOSYS;
225 		goto release_buf;
226 	}
227 
228 	if (buf_ops == NULL) {
229 		/*
230 		 * Re-read the superblock so the buffer is correctly sized,
231 		 * and properly verified.
232 		 */
233 		xfs_buf_relse(bp);
234 		sector_size = sbp->sb_sectsize;
235 		buf_ops = loud ? &xfs_sb_buf_ops : &xfs_sb_quiet_buf_ops;
236 		goto reread;
237 	}
238 
239 	mp->m_features |= xfs_sb_version_to_features(sbp);
240 	xfs_reinit_percpu_counters(mp);
241 
242 	/*
243 	 * If logged xattrs are enabled after log recovery finishes, then set
244 	 * the opstate so that log recovery will work properly.
245 	 */
246 	if (xfs_sb_version_haslogxattrs(&mp->m_sb))
247 		xfs_set_using_logged_xattrs(mp);
248 
249 	/* no need to be quiet anymore, so reset the buf ops */
250 	bp->b_ops = &xfs_sb_buf_ops;
251 
252 	mp->m_sb_bp = bp;
253 	xfs_buf_unlock(bp);
254 	return 0;
255 
256 release_buf:
257 	xfs_buf_relse(bp);
258 	return error;
259 }
260 
261 /*
262  * If the sunit/swidth change would move the precomputed root inode value, we
263  * must reject the ondisk change because repair will stumble over that.
264  * However, we allow the mount to proceed because we never rejected this
265  * combination before.  Returns true to update the sb, false otherwise.
266  */
267 static inline int
268 xfs_check_new_dalign(
269 	struct xfs_mount	*mp,
270 	int			new_dalign,
271 	bool			*update_sb)
272 {
273 	struct xfs_sb		*sbp = &mp->m_sb;
274 	xfs_ino_t		calc_ino;
275 
276 	calc_ino = xfs_ialloc_calc_rootino(mp, new_dalign);
277 	trace_xfs_check_new_dalign(mp, new_dalign, calc_ino);
278 
279 	if (sbp->sb_rootino == calc_ino) {
280 		*update_sb = true;
281 		return 0;
282 	}
283 
284 	xfs_warn(mp,
285 "Cannot change stripe alignment; would require moving root inode.");
286 
287 	/*
288 	 * XXX: Next time we add a new incompat feature, this should start
289 	 * returning -EINVAL to fail the mount.  Until then, spit out a warning
290 	 * that we're ignoring the administrator's instructions.
291 	 */
292 	xfs_warn(mp, "Skipping superblock stripe alignment update.");
293 	*update_sb = false;
294 	return 0;
295 }
296 
297 /*
298  * If we were provided with new sunit/swidth values as mount options, make sure
299  * that they pass basic alignment and superblock feature checks, and convert
300  * them into the same units (FSB) that everything else expects.  This step
301  * /must/ be done before computing the inode geometry.
302  */
303 STATIC int
304 xfs_validate_new_dalign(
305 	struct xfs_mount	*mp)
306 {
307 	if (mp->m_dalign == 0)
308 		return 0;
309 
310 	/*
311 	 * If stripe unit and stripe width are not multiples
312 	 * of the fs blocksize turn off alignment.
313 	 */
314 	if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
315 	    (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
316 		xfs_warn(mp,
317 	"alignment check failed: sunit/swidth vs. blocksize(%d)",
318 			mp->m_sb.sb_blocksize);
319 		return -EINVAL;
320 	}
321 
322 	/*
323 	 * Convert the stripe unit and width to FSBs.
324 	 */
325 	mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
326 	if (mp->m_dalign && (mp->m_sb.sb_agblocks % mp->m_dalign)) {
327 		xfs_warn(mp,
328 	"alignment check failed: sunit/swidth vs. agsize(%d)",
329 			mp->m_sb.sb_agblocks);
330 		return -EINVAL;
331 	}
332 
333 	if (!mp->m_dalign) {
334 		xfs_warn(mp,
335 	"alignment check failed: sunit(%d) less than bsize(%d)",
336 			mp->m_dalign, mp->m_sb.sb_blocksize);
337 		return -EINVAL;
338 	}
339 
340 	mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
341 
342 	if (!xfs_has_dalign(mp)) {
343 		xfs_warn(mp,
344 "cannot change alignment: superblock does not support data alignment");
345 		return -EINVAL;
346 	}
347 
348 	return 0;
349 }
350 
351 /* Update alignment values based on mount options and sb values. */
352 STATIC int
353 xfs_update_alignment(
354 	struct xfs_mount	*mp)
355 {
356 	struct xfs_sb		*sbp = &mp->m_sb;
357 
358 	if (mp->m_dalign) {
359 		bool		update_sb;
360 		int		error;
361 
362 		if (sbp->sb_unit == mp->m_dalign &&
363 		    sbp->sb_width == mp->m_swidth)
364 			return 0;
365 
366 		error = xfs_check_new_dalign(mp, mp->m_dalign, &update_sb);
367 		if (error || !update_sb)
368 			return error;
369 
370 		sbp->sb_unit = mp->m_dalign;
371 		sbp->sb_width = mp->m_swidth;
372 		mp->m_update_sb = true;
373 	} else if (!xfs_has_noalign(mp) && xfs_has_dalign(mp)) {
374 		mp->m_dalign = sbp->sb_unit;
375 		mp->m_swidth = sbp->sb_width;
376 	}
377 
378 	return 0;
379 }
380 
381 /*
382  * precalculate the low space thresholds for dynamic speculative preallocation.
383  */
384 void
385 xfs_set_low_space_thresholds(
386 	struct xfs_mount	*mp)
387 {
388 	uint64_t		dblocks = mp->m_sb.sb_dblocks;
389 	uint64_t		rtexts = mp->m_sb.sb_rextents;
390 	int			i;
391 
392 	do_div(dblocks, 100);
393 	do_div(rtexts, 100);
394 
395 	for (i = 0; i < XFS_LOWSP_MAX; i++) {
396 		mp->m_low_space[i] = dblocks * (i + 1);
397 		mp->m_low_rtexts[i] = rtexts * (i + 1);
398 	}
399 }
400 
401 /*
402  * Check that the data (and log if separate) is an ok size.
403  */
404 STATIC int
405 xfs_check_sizes(
406 	struct xfs_mount *mp)
407 {
408 	struct xfs_buf	*bp;
409 	xfs_daddr_t	d;
410 	int		error;
411 
412 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
413 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
414 		xfs_warn(mp, "filesystem size mismatch detected");
415 		return -EFBIG;
416 	}
417 	error = xfs_buf_read_uncached(mp->m_ddev_targp,
418 					d - XFS_FSS_TO_BB(mp, 1),
419 					XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
420 	if (error) {
421 		xfs_warn(mp, "last sector read failed");
422 		return error;
423 	}
424 	xfs_buf_relse(bp);
425 
426 	if (mp->m_logdev_targp == mp->m_ddev_targp)
427 		return 0;
428 
429 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
430 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
431 		xfs_warn(mp, "log size mismatch detected");
432 		return -EFBIG;
433 	}
434 	error = xfs_buf_read_uncached(mp->m_logdev_targp,
435 					d - XFS_FSB_TO_BB(mp, 1),
436 					XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
437 	if (error) {
438 		xfs_warn(mp, "log device read failed");
439 		return error;
440 	}
441 	xfs_buf_relse(bp);
442 	return 0;
443 }
444 
445 /*
446  * Clear the quotaflags in memory and in the superblock.
447  */
448 int
449 xfs_mount_reset_sbqflags(
450 	struct xfs_mount	*mp)
451 {
452 	mp->m_qflags = 0;
453 
454 	/* It is OK to look at sb_qflags in the mount path without m_sb_lock. */
455 	if (mp->m_sb.sb_qflags == 0)
456 		return 0;
457 	spin_lock(&mp->m_sb_lock);
458 	mp->m_sb.sb_qflags = 0;
459 	spin_unlock(&mp->m_sb_lock);
460 
461 	if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
462 		return 0;
463 
464 	return xfs_sync_sb(mp, false);
465 }
466 
467 uint64_t
468 xfs_default_resblks(xfs_mount_t *mp)
469 {
470 	uint64_t resblks;
471 
472 	/*
473 	 * We default to 5% or 8192 fsbs of space reserved, whichever is
474 	 * smaller.  This is intended to cover concurrent allocation
475 	 * transactions when we initially hit enospc. These each require a 4
476 	 * block reservation. Hence by default we cover roughly 2000 concurrent
477 	 * allocation reservations.
478 	 */
479 	resblks = mp->m_sb.sb_dblocks;
480 	do_div(resblks, 20);
481 	resblks = min_t(uint64_t, resblks, 8192);
482 	return resblks;
483 }
484 
485 /* Ensure the summary counts are correct. */
486 STATIC int
487 xfs_check_summary_counts(
488 	struct xfs_mount	*mp)
489 {
490 	int			error = 0;
491 
492 	/*
493 	 * The AG0 superblock verifier rejects in-progress filesystems,
494 	 * so we should never see the flag set this far into mounting.
495 	 */
496 	if (mp->m_sb.sb_inprogress) {
497 		xfs_err(mp, "sb_inprogress set after log recovery??");
498 		WARN_ON(1);
499 		return -EFSCORRUPTED;
500 	}
501 
502 	/*
503 	 * Now the log is mounted, we know if it was an unclean shutdown or
504 	 * not. If it was, with the first phase of recovery has completed, we
505 	 * have consistent AG blocks on disk. We have not recovered EFIs yet,
506 	 * but they are recovered transactionally in the second recovery phase
507 	 * later.
508 	 *
509 	 * If the log was clean when we mounted, we can check the summary
510 	 * counters.  If any of them are obviously incorrect, we can recompute
511 	 * them from the AGF headers in the next step.
512 	 */
513 	if (xfs_is_clean(mp) &&
514 	    (mp->m_sb.sb_fdblocks > mp->m_sb.sb_dblocks ||
515 	     !xfs_verify_icount(mp, mp->m_sb.sb_icount) ||
516 	     mp->m_sb.sb_ifree > mp->m_sb.sb_icount))
517 		xfs_fs_mark_sick(mp, XFS_SICK_FS_COUNTERS);
518 
519 	/*
520 	 * We can safely re-initialise incore superblock counters from the
521 	 * per-ag data. These may not be correct if the filesystem was not
522 	 * cleanly unmounted, so we waited for recovery to finish before doing
523 	 * this.
524 	 *
525 	 * If the filesystem was cleanly unmounted or the previous check did
526 	 * not flag anything weird, then we can trust the values in the
527 	 * superblock to be correct and we don't need to do anything here.
528 	 * Otherwise, recalculate the summary counters.
529 	 */
530 	if ((xfs_has_lazysbcount(mp) && !xfs_is_clean(mp)) ||
531 	    xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS)) {
532 		error = xfs_initialize_perag_data(mp, mp->m_sb.sb_agcount);
533 		if (error)
534 			return error;
535 	}
536 
537 	/*
538 	 * Older kernels misused sb_frextents to reflect both incore
539 	 * reservations made by running transactions and the actual count of
540 	 * free rt extents in the ondisk metadata.  Transactions committed
541 	 * during runtime can therefore contain a superblock update that
542 	 * undercounts the number of free rt extents tracked in the rt bitmap.
543 	 * A clean unmount record will have the correct frextents value since
544 	 * there can be no other transactions running at that point.
545 	 *
546 	 * If we're mounting the rt volume after recovering the log, recompute
547 	 * frextents from the rtbitmap file to fix the inconsistency.
548 	 */
549 	if (xfs_has_realtime(mp) && !xfs_is_clean(mp)) {
550 		error = xfs_rtalloc_reinit_frextents(mp);
551 		if (error)
552 			return error;
553 	}
554 
555 	return 0;
556 }
557 
558 static void
559 xfs_unmount_check(
560 	struct xfs_mount	*mp)
561 {
562 	if (xfs_is_shutdown(mp))
563 		return;
564 
565 	if (percpu_counter_sum(&mp->m_ifree) >
566 			percpu_counter_sum(&mp->m_icount)) {
567 		xfs_alert(mp, "ifree/icount mismatch at unmount");
568 		xfs_fs_mark_sick(mp, XFS_SICK_FS_COUNTERS);
569 	}
570 }
571 
572 /*
573  * Flush and reclaim dirty inodes in preparation for unmount. Inodes and
574  * internal inode structures can be sitting in the CIL and AIL at this point,
575  * so we need to unpin them, write them back and/or reclaim them before unmount
576  * can proceed.  In other words, callers are required to have inactivated all
577  * inodes.
578  *
579  * An inode cluster that has been freed can have its buffer still pinned in
580  * memory because the transaction is still sitting in a iclog. The stale inodes
581  * on that buffer will be pinned to the buffer until the transaction hits the
582  * disk and the callbacks run. Pushing the AIL will skip the stale inodes and
583  * may never see the pinned buffer, so nothing will push out the iclog and
584  * unpin the buffer.
585  *
586  * Hence we need to force the log to unpin everything first. However, log
587  * forces don't wait for the discards they issue to complete, so we have to
588  * explicitly wait for them to complete here as well.
589  *
590  * Then we can tell the world we are unmounting so that error handling knows
591  * that the filesystem is going away and we should error out anything that we
592  * have been retrying in the background.  This will prevent never-ending
593  * retries in AIL pushing from hanging the unmount.
594  *
595  * Finally, we can push the AIL to clean all the remaining dirty objects, then
596  * reclaim the remaining inodes that are still in memory at this point in time.
597  */
598 static void
599 xfs_unmount_flush_inodes(
600 	struct xfs_mount	*mp)
601 {
602 	xfs_log_force(mp, XFS_LOG_SYNC);
603 	xfs_extent_busy_wait_all(mp);
604 	flush_workqueue(xfs_discard_wq);
605 
606 	xfs_set_unmounting(mp);
607 
608 	xfs_ail_push_all_sync(mp->m_ail);
609 	xfs_inodegc_stop(mp);
610 	cancel_delayed_work_sync(&mp->m_reclaim_work);
611 	xfs_reclaim_inodes(mp);
612 	xfs_health_unmount(mp);
613 }
614 
615 static void
616 xfs_mount_setup_inode_geom(
617 	struct xfs_mount	*mp)
618 {
619 	struct xfs_ino_geometry *igeo = M_IGEO(mp);
620 
621 	igeo->attr_fork_offset = xfs_bmap_compute_attr_offset(mp);
622 	ASSERT(igeo->attr_fork_offset < XFS_LITINO(mp));
623 
624 	xfs_ialloc_setup_geometry(mp);
625 }
626 
627 /* Mount the metadata directory tree root. */
628 STATIC int
629 xfs_mount_setup_metadir(
630 	struct xfs_mount	*mp)
631 {
632 	int			error;
633 
634 	/* Load the metadata directory root inode into memory. */
635 	error = xfs_metafile_iget(mp, mp->m_sb.sb_metadirino, XFS_METAFILE_DIR,
636 			&mp->m_metadirip);
637 	if (error)
638 		xfs_warn(mp, "Failed to load metadir root directory, error %d",
639 				error);
640 	return error;
641 }
642 
643 /* Compute maximum possible height for per-AG btree types for this fs. */
644 static inline void
645 xfs_agbtree_compute_maxlevels(
646 	struct xfs_mount	*mp)
647 {
648 	unsigned int		levels;
649 
650 	levels = max(mp->m_alloc_maxlevels, M_IGEO(mp)->inobt_maxlevels);
651 	levels = max(levels, mp->m_rmap_maxlevels);
652 	mp->m_agbtree_maxlevels = max(levels, mp->m_refc_maxlevels);
653 }
654 
655 /* Compute maximum possible height for realtime btree types for this fs. */
656 static inline void
657 xfs_rtbtree_compute_maxlevels(
658 	struct xfs_mount	*mp)
659 {
660 	mp->m_rtbtree_maxlevels = max(mp->m_rtrmap_maxlevels,
661 				      mp->m_rtrefc_maxlevels);
662 }
663 
664 /*
665  * This function does the following on an initial mount of a file system:
666  *	- reads the superblock from disk and init the mount struct
667  *	- if we're a 32-bit kernel, do a size check on the superblock
668  *		so we don't mount terabyte filesystems
669  *	- init mount struct realtime fields
670  *	- allocate inode hash table for fs
671  *	- init directory manager
672  *	- perform recovery and init the log manager
673  */
674 int
675 xfs_mountfs(
676 	struct xfs_mount	*mp)
677 {
678 	struct xfs_sb		*sbp = &(mp->m_sb);
679 	struct xfs_inode	*rip;
680 	struct xfs_ino_geometry	*igeo = M_IGEO(mp);
681 	uint			quotamount = 0;
682 	uint			quotaflags = 0;
683 	int			error = 0;
684 
685 	xfs_sb_mount_common(mp, sbp);
686 
687 	/*
688 	 * Check for a mismatched features2 values.  Older kernels read & wrote
689 	 * into the wrong sb offset for sb_features2 on some platforms due to
690 	 * xfs_sb_t not being 64bit size aligned when sb_features2 was added,
691 	 * which made older superblock reading/writing routines swap it as a
692 	 * 64-bit value.
693 	 *
694 	 * For backwards compatibility, we make both slots equal.
695 	 *
696 	 * If we detect a mismatched field, we OR the set bits into the existing
697 	 * features2 field in case it has already been modified; we don't want
698 	 * to lose any features.  We then update the bad location with the ORed
699 	 * value so that older kernels will see any features2 flags. The
700 	 * superblock writeback code ensures the new sb_features2 is copied to
701 	 * sb_bad_features2 before it is logged or written to disk.
702 	 */
703 	if (xfs_sb_has_mismatched_features2(sbp)) {
704 		xfs_warn(mp, "correcting sb_features alignment problem");
705 		sbp->sb_features2 |= sbp->sb_bad_features2;
706 		mp->m_update_sb = true;
707 	}
708 
709 
710 	/* always use v2 inodes by default now */
711 	if (!(mp->m_sb.sb_versionnum & XFS_SB_VERSION_NLINKBIT)) {
712 		mp->m_sb.sb_versionnum |= XFS_SB_VERSION_NLINKBIT;
713 		mp->m_features |= XFS_FEAT_NLINK;
714 		mp->m_update_sb = true;
715 	}
716 
717 	/*
718 	 * If we were given new sunit/swidth options, do some basic validation
719 	 * checks and convert the incore dalign and swidth values to the
720 	 * same units (FSB) that everything else uses.  This /must/ happen
721 	 * before computing the inode geometry.
722 	 */
723 	error = xfs_validate_new_dalign(mp);
724 	if (error)
725 		goto out;
726 
727 	xfs_alloc_compute_maxlevels(mp);
728 	xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
729 	xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
730 	xfs_mount_setup_inode_geom(mp);
731 	xfs_rmapbt_compute_maxlevels(mp);
732 	xfs_rtrmapbt_compute_maxlevels(mp);
733 	xfs_refcountbt_compute_maxlevels(mp);
734 	xfs_rtrefcountbt_compute_maxlevels(mp);
735 
736 	xfs_agbtree_compute_maxlevels(mp);
737 	xfs_rtbtree_compute_maxlevels(mp);
738 
739 	/*
740 	 * Check if sb_agblocks is aligned at stripe boundary.  If sb_agblocks
741 	 * is NOT aligned turn off m_dalign since allocator alignment is within
742 	 * an ag, therefore ag has to be aligned at stripe boundary.  Note that
743 	 * we must compute the free space and rmap btree geometry before doing
744 	 * this.
745 	 */
746 	error = xfs_update_alignment(mp);
747 	if (error)
748 		goto out;
749 
750 	/* enable fail_at_unmount as default */
751 	mp->m_fail_unmount = true;
752 
753 	super_set_sysfs_name_id(mp->m_super);
754 
755 	error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype,
756 			       NULL, mp->m_super->s_id);
757 	if (error)
758 		goto out;
759 
760 	error = xfs_sysfs_init(&mp->m_stats.xs_kobj, &xfs_stats_ktype,
761 			       &mp->m_kobj, "stats");
762 	if (error)
763 		goto out_remove_sysfs;
764 
765 	xchk_stats_register(mp->m_scrub_stats, mp->m_debugfs);
766 
767 	error = xfs_error_sysfs_init(mp);
768 	if (error)
769 		goto out_remove_scrub_stats;
770 
771 	error = xfs_errortag_init(mp);
772 	if (error)
773 		goto out_remove_error_sysfs;
774 
775 	error = xfs_uuid_mount(mp);
776 	if (error)
777 		goto out_remove_errortag;
778 
779 	/*
780 	 * Update the preferred write size based on the information from the
781 	 * on-disk superblock.
782 	 */
783 	mp->m_allocsize_log =
784 		max_t(uint32_t, sbp->sb_blocklog, mp->m_allocsize_log);
785 	mp->m_allocsize_blocks = 1U << (mp->m_allocsize_log - sbp->sb_blocklog);
786 
787 	/* set the low space thresholds for dynamic preallocation */
788 	xfs_set_low_space_thresholds(mp);
789 
790 	/*
791 	 * If enabled, sparse inode chunk alignment is expected to match the
792 	 * cluster size. Full inode chunk alignment must match the chunk size,
793 	 * but that is checked on sb read verification...
794 	 */
795 	if (xfs_has_sparseinodes(mp) &&
796 	    mp->m_sb.sb_spino_align !=
797 			XFS_B_TO_FSBT(mp, igeo->inode_cluster_size_raw)) {
798 		xfs_warn(mp,
799 	"Sparse inode block alignment (%u) must match cluster size (%llu).",
800 			 mp->m_sb.sb_spino_align,
801 			 XFS_B_TO_FSBT(mp, igeo->inode_cluster_size_raw));
802 		error = -EINVAL;
803 		goto out_remove_uuid;
804 	}
805 
806 	/*
807 	 * Check that the data (and log if separate) is an ok size.
808 	 */
809 	error = xfs_check_sizes(mp);
810 	if (error)
811 		goto out_remove_uuid;
812 
813 	/*
814 	 * Initialize realtime fields in the mount structure
815 	 */
816 	error = xfs_rtmount_init(mp);
817 	if (error) {
818 		xfs_warn(mp, "RT mount failed");
819 		goto out_remove_uuid;
820 	}
821 
822 	/*
823 	 *  Copies the low order bits of the timestamp and the randomly
824 	 *  set "sequence" number out of a UUID.
825 	 */
826 	mp->m_fixedfsid[0] =
827 		(get_unaligned_be16(&sbp->sb_uuid.b[8]) << 16) |
828 		 get_unaligned_be16(&sbp->sb_uuid.b[4]);
829 	mp->m_fixedfsid[1] = get_unaligned_be32(&sbp->sb_uuid.b[0]);
830 
831 	error = xfs_da_mount(mp);
832 	if (error) {
833 		xfs_warn(mp, "Failed dir/attr init: %d", error);
834 		goto out_remove_uuid;
835 	}
836 
837 	/*
838 	 * Initialize the precomputed transaction reservations values.
839 	 */
840 	xfs_trans_init(mp);
841 
842 	/*
843 	 * Allocate and initialize the per-ag data.
844 	 */
845 	error = xfs_initialize_perag(mp, 0, sbp->sb_agcount,
846 			mp->m_sb.sb_dblocks, &mp->m_maxagi);
847 	if (error) {
848 		xfs_warn(mp, "Failed per-ag init: %d", error);
849 		goto out_free_dir;
850 	}
851 
852 	error = xfs_initialize_rtgroups(mp, 0, sbp->sb_rgcount,
853 			mp->m_sb.sb_rextents);
854 	if (error) {
855 		xfs_warn(mp, "Failed rtgroup init: %d", error);
856 		goto out_free_perag;
857 	}
858 
859 	if (XFS_IS_CORRUPT(mp, !sbp->sb_logblocks)) {
860 		xfs_warn(mp, "no log defined");
861 		error = -EFSCORRUPTED;
862 		goto out_free_rtgroup;
863 	}
864 
865 	error = xfs_inodegc_register_shrinker(mp);
866 	if (error)
867 		goto out_fail_wait;
868 
869 	/*
870 	 * If we're resuming quota status, pick up the preliminary qflags from
871 	 * the ondisk superblock so that we know if we should recover dquots.
872 	 */
873 	if (xfs_is_resuming_quotaon(mp))
874 		xfs_qm_resume_quotaon(mp);
875 
876 	/*
877 	 * Log's mount-time initialization. The first part of recovery can place
878 	 * some items on the AIL, to be handled when recovery is finished or
879 	 * cancelled.
880 	 */
881 	error = xfs_log_mount(mp, mp->m_logdev_targp,
882 			      XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
883 			      XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
884 	if (error) {
885 		xfs_warn(mp, "log mount failed");
886 		goto out_inodegc_shrinker;
887 	}
888 
889 	/*
890 	 * If we're resuming quota status and recovered the log, re-sample the
891 	 * qflags from the ondisk superblock now that we've recovered it, just
892 	 * in case someone shut down enforcement just before a crash.
893 	 */
894 	if (xfs_clear_resuming_quotaon(mp) && xlog_recovery_needed(mp->m_log))
895 		xfs_qm_resume_quotaon(mp);
896 
897 	/*
898 	 * If logged xattrs are still enabled after log recovery finishes, then
899 	 * they'll be available until unmount.  Otherwise, turn them off.
900 	 */
901 	if (xfs_sb_version_haslogxattrs(&mp->m_sb))
902 		xfs_set_using_logged_xattrs(mp);
903 	else
904 		xfs_clear_using_logged_xattrs(mp);
905 
906 	/* Enable background inode inactivation workers. */
907 	xfs_inodegc_start(mp);
908 	xfs_blockgc_start(mp);
909 
910 	/*
911 	 * Now that we've recovered any pending superblock feature bit
912 	 * additions, we can finish setting up the attr2 behaviour for the
913 	 * mount. The noattr2 option overrides the superblock flag, so only
914 	 * check the superblock feature flag if the mount option is not set.
915 	 */
916 	if (xfs_has_noattr2(mp)) {
917 		mp->m_features &= ~XFS_FEAT_ATTR2;
918 	} else if (!xfs_has_attr2(mp) &&
919 		   (mp->m_sb.sb_features2 & XFS_SB_VERSION2_ATTR2BIT)) {
920 		mp->m_features |= XFS_FEAT_ATTR2;
921 	}
922 
923 	if (xfs_has_metadir(mp)) {
924 		error = xfs_mount_setup_metadir(mp);
925 		if (error)
926 			goto out_free_metadir;
927 	}
928 
929 	/*
930 	 * Get and sanity-check the root inode.
931 	 * Save the pointer to it in the mount structure.
932 	 */
933 	error = xfs_iget(mp, NULL, sbp->sb_rootino, XFS_IGET_UNTRUSTED,
934 			 XFS_ILOCK_EXCL, &rip);
935 	if (error) {
936 		xfs_warn(mp,
937 			"Failed to read root inode 0x%llx, error %d",
938 			sbp->sb_rootino, -error);
939 		goto out_free_metadir;
940 	}
941 
942 	ASSERT(rip != NULL);
943 
944 	if (XFS_IS_CORRUPT(mp, !S_ISDIR(VFS_I(rip)->i_mode))) {
945 		xfs_warn(mp, "corrupted root inode %llu: not a directory",
946 			(unsigned long long)rip->i_ino);
947 		xfs_iunlock(rip, XFS_ILOCK_EXCL);
948 		error = -EFSCORRUPTED;
949 		goto out_rele_rip;
950 	}
951 	mp->m_rootip = rip;	/* save it */
952 
953 	xfs_iunlock(rip, XFS_ILOCK_EXCL);
954 
955 	/*
956 	 * Initialize realtime inode pointers in the mount structure
957 	 */
958 	error = xfs_rtmount_inodes(mp);
959 	if (error) {
960 		/*
961 		 * Free up the root inode.
962 		 */
963 		xfs_warn(mp, "failed to read RT inodes");
964 		goto out_rele_rip;
965 	}
966 
967 	/* Make sure the summary counts are ok. */
968 	error = xfs_check_summary_counts(mp);
969 	if (error)
970 		goto out_rtunmount;
971 
972 	/*
973 	 * If this is a read-only mount defer the superblock updates until
974 	 * the next remount into writeable mode.  Otherwise we would never
975 	 * perform the update e.g. for the root filesystem.
976 	 */
977 	if (mp->m_update_sb && !xfs_is_readonly(mp)) {
978 		error = xfs_sync_sb(mp, false);
979 		if (error) {
980 			xfs_warn(mp, "failed to write sb changes");
981 			goto out_rtunmount;
982 		}
983 	}
984 
985 	/*
986 	 * Initialise the XFS quota management subsystem for this mount
987 	 */
988 	if (XFS_IS_QUOTA_ON(mp)) {
989 		error = xfs_qm_newmount(mp, &quotamount, &quotaflags);
990 		if (error)
991 			goto out_rtunmount;
992 	} else {
993 		/*
994 		 * If a file system had quotas running earlier, but decided to
995 		 * mount without -o uquota/pquota/gquota options, revoke the
996 		 * quotachecked license.
997 		 */
998 		if (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_ACCT) {
999 			xfs_notice(mp, "resetting quota flags");
1000 			error = xfs_mount_reset_sbqflags(mp);
1001 			if (error)
1002 				goto out_rtunmount;
1003 		}
1004 	}
1005 
1006 	/*
1007 	 * Finish recovering the file system.  This part needed to be delayed
1008 	 * until after the root and real-time bitmap inodes were consistently
1009 	 * read in.  Temporarily create per-AG space reservations for metadata
1010 	 * btree shape changes because space freeing transactions (for inode
1011 	 * inactivation) require the per-AG reservation in lieu of reserving
1012 	 * blocks.
1013 	 */
1014 	error = xfs_fs_reserve_ag_blocks(mp);
1015 	if (error && error == -ENOSPC)
1016 		xfs_warn(mp,
1017 	"ENOSPC reserving per-AG metadata pool, log recovery may fail.");
1018 	error = xfs_log_mount_finish(mp);
1019 	xfs_fs_unreserve_ag_blocks(mp);
1020 	if (error) {
1021 		xfs_warn(mp, "log mount finish failed");
1022 		goto out_rtunmount;
1023 	}
1024 
1025 	/*
1026 	 * Now the log is fully replayed, we can transition to full read-only
1027 	 * mode for read-only mounts. This will sync all the metadata and clean
1028 	 * the log so that the recovery we just performed does not have to be
1029 	 * replayed again on the next mount.
1030 	 *
1031 	 * We use the same quiesce mechanism as the rw->ro remount, as they are
1032 	 * semantically identical operations.
1033 	 */
1034 	if (xfs_is_readonly(mp) && !xfs_has_norecovery(mp))
1035 		xfs_log_clean(mp);
1036 
1037 	/*
1038 	 * Complete the quota initialisation, post-log-replay component.
1039 	 */
1040 	if (quotamount) {
1041 		ASSERT(mp->m_qflags == 0);
1042 		mp->m_qflags = quotaflags;
1043 
1044 		xfs_qm_mount_quotas(mp);
1045 	}
1046 
1047 	/*
1048 	 * Now we are mounted, reserve a small amount of unused space for
1049 	 * privileged transactions. This is needed so that transaction
1050 	 * space required for critical operations can dip into this pool
1051 	 * when at ENOSPC. This is needed for operations like create with
1052 	 * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
1053 	 * are not allowed to use this reserved space.
1054 	 *
1055 	 * This may drive us straight to ENOSPC on mount, but that implies
1056 	 * we were already there on the last unmount. Warn if this occurs.
1057 	 */
1058 	if (!xfs_is_readonly(mp)) {
1059 		error = xfs_reserve_blocks(mp, xfs_default_resblks(mp));
1060 		if (error)
1061 			xfs_warn(mp,
1062 	"Unable to allocate reserve blocks. Continuing without reserve pool.");
1063 
1064 		/* Reserve AG blocks for future btree expansion. */
1065 		error = xfs_fs_reserve_ag_blocks(mp);
1066 		if (error && error != -ENOSPC)
1067 			goto out_agresv;
1068 	}
1069 
1070 	return 0;
1071 
1072  out_agresv:
1073 	xfs_fs_unreserve_ag_blocks(mp);
1074 	xfs_qm_unmount_quotas(mp);
1075  out_rtunmount:
1076 	xfs_rtunmount_inodes(mp);
1077  out_rele_rip:
1078 	xfs_irele(rip);
1079 	/* Clean out dquots that might be in memory after quotacheck. */
1080 	xfs_qm_unmount(mp);
1081  out_free_metadir:
1082 	if (mp->m_metadirip)
1083 		xfs_irele(mp->m_metadirip);
1084 
1085 	/*
1086 	 * Inactivate all inodes that might still be in memory after a log
1087 	 * intent recovery failure so that reclaim can free them.  Metadata
1088 	 * inodes and the root directory shouldn't need inactivation, but the
1089 	 * mount failed for some reason, so pull down all the state and flee.
1090 	 */
1091 	xfs_inodegc_flush(mp);
1092 
1093 	/*
1094 	 * Flush all inode reclamation work and flush the log.
1095 	 * We have to do this /after/ rtunmount and qm_unmount because those
1096 	 * two will have scheduled delayed reclaim for the rt/quota inodes.
1097 	 *
1098 	 * This is slightly different from the unmountfs call sequence
1099 	 * because we could be tearing down a partially set up mount.  In
1100 	 * particular, if log_mount_finish fails we bail out without calling
1101 	 * qm_unmount_quotas and therefore rely on qm_unmount to release the
1102 	 * quota inodes.
1103 	 */
1104 	xfs_unmount_flush_inodes(mp);
1105 	xfs_log_mount_cancel(mp);
1106  out_inodegc_shrinker:
1107 	shrinker_free(mp->m_inodegc_shrinker);
1108  out_fail_wait:
1109 	if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
1110 		xfs_buftarg_drain(mp->m_logdev_targp);
1111 	xfs_buftarg_drain(mp->m_ddev_targp);
1112  out_free_rtgroup:
1113 	xfs_free_rtgroups(mp, 0, mp->m_sb.sb_rgcount);
1114  out_free_perag:
1115 	xfs_free_perag_range(mp, 0, mp->m_sb.sb_agcount);
1116  out_free_dir:
1117 	xfs_da_unmount(mp);
1118  out_remove_uuid:
1119 	xfs_uuid_unmount(mp);
1120  out_remove_errortag:
1121 	xfs_errortag_del(mp);
1122  out_remove_error_sysfs:
1123 	xfs_error_sysfs_del(mp);
1124  out_remove_scrub_stats:
1125 	xchk_stats_unregister(mp->m_scrub_stats);
1126 	xfs_sysfs_del(&mp->m_stats.xs_kobj);
1127  out_remove_sysfs:
1128 	xfs_sysfs_del(&mp->m_kobj);
1129  out:
1130 	return error;
1131 }
1132 
1133 /*
1134  * This flushes out the inodes,dquots and the superblock, unmounts the
1135  * log and makes sure that incore structures are freed.
1136  */
1137 void
1138 xfs_unmountfs(
1139 	struct xfs_mount	*mp)
1140 {
1141 	int			error;
1142 
1143 	/*
1144 	 * Perform all on-disk metadata updates required to inactivate inodes
1145 	 * that the VFS evicted earlier in the unmount process.  Freeing inodes
1146 	 * and discarding CoW fork preallocations can cause shape changes to
1147 	 * the free inode and refcount btrees, respectively, so we must finish
1148 	 * this before we discard the metadata space reservations.  Metadata
1149 	 * inodes and the root directory do not require inactivation.
1150 	 */
1151 	xfs_inodegc_flush(mp);
1152 
1153 	xfs_blockgc_stop(mp);
1154 	xfs_fs_unreserve_ag_blocks(mp);
1155 	xfs_qm_unmount_quotas(mp);
1156 	xfs_rtunmount_inodes(mp);
1157 	xfs_irele(mp->m_rootip);
1158 	if (mp->m_metadirip)
1159 		xfs_irele(mp->m_metadirip);
1160 
1161 	xfs_unmount_flush_inodes(mp);
1162 
1163 	xfs_qm_unmount(mp);
1164 
1165 	/*
1166 	 * Unreserve any blocks we have so that when we unmount we don't account
1167 	 * the reserved free space as used. This is really only necessary for
1168 	 * lazy superblock counting because it trusts the incore superblock
1169 	 * counters to be absolutely correct on clean unmount.
1170 	 *
1171 	 * We don't bother correcting this elsewhere for lazy superblock
1172 	 * counting because on mount of an unclean filesystem we reconstruct the
1173 	 * correct counter value and this is irrelevant.
1174 	 *
1175 	 * For non-lazy counter filesystems, this doesn't matter at all because
1176 	 * we only every apply deltas to the superblock and hence the incore
1177 	 * value does not matter....
1178 	 */
1179 	error = xfs_reserve_blocks(mp, 0);
1180 	if (error)
1181 		xfs_warn(mp, "Unable to free reserved block pool. "
1182 				"Freespace may not be correct on next mount.");
1183 	xfs_unmount_check(mp);
1184 
1185 	/*
1186 	 * Indicate that it's ok to clear log incompat bits before cleaning
1187 	 * the log and writing the unmount record.
1188 	 */
1189 	xfs_set_done_with_log_incompat(mp);
1190 	xfs_log_unmount(mp);
1191 	xfs_da_unmount(mp);
1192 	xfs_uuid_unmount(mp);
1193 
1194 #if defined(DEBUG)
1195 	xfs_errortag_clearall(mp);
1196 #endif
1197 	shrinker_free(mp->m_inodegc_shrinker);
1198 	xfs_free_rtgroups(mp, 0, mp->m_sb.sb_rgcount);
1199 	xfs_free_perag_range(mp, 0, mp->m_sb.sb_agcount);
1200 	xfs_errortag_del(mp);
1201 	xfs_error_sysfs_del(mp);
1202 	xchk_stats_unregister(mp->m_scrub_stats);
1203 	xfs_sysfs_del(&mp->m_stats.xs_kobj);
1204 	xfs_sysfs_del(&mp->m_kobj);
1205 }
1206 
1207 /*
1208  * Determine whether modifications can proceed. The caller specifies the minimum
1209  * freeze level for which modifications should not be allowed. This allows
1210  * certain operations to proceed while the freeze sequence is in progress, if
1211  * necessary.
1212  */
1213 bool
1214 xfs_fs_writable(
1215 	struct xfs_mount	*mp,
1216 	int			level)
1217 {
1218 	ASSERT(level > SB_UNFROZEN);
1219 	if ((mp->m_super->s_writers.frozen >= level) ||
1220 	    xfs_is_shutdown(mp) || xfs_is_readonly(mp))
1221 		return false;
1222 
1223 	return true;
1224 }
1225 
1226 void
1227 xfs_add_freecounter(
1228 	struct xfs_mount	*mp,
1229 	struct percpu_counter	*counter,
1230 	uint64_t		delta)
1231 {
1232 	bool			has_resv_pool = (counter == &mp->m_fdblocks);
1233 	uint64_t		res_used;
1234 
1235 	/*
1236 	 * If the reserve pool is depleted, put blocks back into it first.
1237 	 * Most of the time the pool is full.
1238 	 */
1239 	if (!has_resv_pool || mp->m_resblks == mp->m_resblks_avail) {
1240 		percpu_counter_add(counter, delta);
1241 		return;
1242 	}
1243 
1244 	spin_lock(&mp->m_sb_lock);
1245 	res_used = mp->m_resblks - mp->m_resblks_avail;
1246 	if (res_used > delta) {
1247 		mp->m_resblks_avail += delta;
1248 	} else {
1249 		delta -= res_used;
1250 		mp->m_resblks_avail = mp->m_resblks;
1251 		percpu_counter_add(counter, delta);
1252 	}
1253 	spin_unlock(&mp->m_sb_lock);
1254 }
1255 
1256 int
1257 xfs_dec_freecounter(
1258 	struct xfs_mount	*mp,
1259 	struct percpu_counter	*counter,
1260 	uint64_t		delta,
1261 	bool			rsvd)
1262 {
1263 	int64_t			lcounter;
1264 	uint64_t		set_aside = 0;
1265 	s32			batch;
1266 	bool			has_resv_pool;
1267 
1268 	ASSERT(counter == &mp->m_fdblocks || counter == &mp->m_frextents);
1269 	has_resv_pool = (counter == &mp->m_fdblocks);
1270 	if (rsvd)
1271 		ASSERT(has_resv_pool);
1272 
1273 	/*
1274 	 * Taking blocks away, need to be more accurate the closer we
1275 	 * are to zero.
1276 	 *
1277 	 * If the counter has a value of less than 2 * max batch size,
1278 	 * then make everything serialise as we are real close to
1279 	 * ENOSPC.
1280 	 */
1281 	if (__percpu_counter_compare(counter, 2 * XFS_FDBLOCKS_BATCH,
1282 				     XFS_FDBLOCKS_BATCH) < 0)
1283 		batch = 1;
1284 	else
1285 		batch = XFS_FDBLOCKS_BATCH;
1286 
1287 	/*
1288 	 * Set aside allocbt blocks because these blocks are tracked as free
1289 	 * space but not available for allocation. Technically this means that a
1290 	 * single reservation cannot consume all remaining free space, but the
1291 	 * ratio of allocbt blocks to usable free blocks should be rather small.
1292 	 * The tradeoff without this is that filesystems that maintain high
1293 	 * perag block reservations can over reserve physical block availability
1294 	 * and fail physical allocation, which leads to much more serious
1295 	 * problems (i.e. transaction abort, pagecache discards, etc.) than
1296 	 * slightly premature -ENOSPC.
1297 	 */
1298 	if (has_resv_pool)
1299 		set_aside = xfs_fdblocks_unavailable(mp);
1300 	percpu_counter_add_batch(counter, -((int64_t)delta), batch);
1301 	if (__percpu_counter_compare(counter, set_aside,
1302 				     XFS_FDBLOCKS_BATCH) >= 0) {
1303 		/* we had space! */
1304 		return 0;
1305 	}
1306 
1307 	/*
1308 	 * lock up the sb for dipping into reserves before releasing the space
1309 	 * that took us to ENOSPC.
1310 	 */
1311 	spin_lock(&mp->m_sb_lock);
1312 	percpu_counter_add(counter, delta);
1313 	if (!has_resv_pool || !rsvd)
1314 		goto fdblocks_enospc;
1315 
1316 	lcounter = (long long)mp->m_resblks_avail - delta;
1317 	if (lcounter >= 0) {
1318 		mp->m_resblks_avail = lcounter;
1319 		spin_unlock(&mp->m_sb_lock);
1320 		return 0;
1321 	}
1322 	xfs_warn_once(mp,
1323 "Reserve blocks depleted! Consider increasing reserve pool size.");
1324 
1325 fdblocks_enospc:
1326 	spin_unlock(&mp->m_sb_lock);
1327 	return -ENOSPC;
1328 }
1329 
1330 /*
1331  * Used to free the superblock along various error paths.
1332  */
1333 void
1334 xfs_freesb(
1335 	struct xfs_mount	*mp)
1336 {
1337 	struct xfs_buf		*bp = mp->m_sb_bp;
1338 
1339 	xfs_buf_lock(bp);
1340 	mp->m_sb_bp = NULL;
1341 	xfs_buf_relse(bp);
1342 }
1343 
1344 /*
1345  * If the underlying (data/log/rt) device is readonly, there are some
1346  * operations that cannot proceed.
1347  */
1348 int
1349 xfs_dev_is_read_only(
1350 	struct xfs_mount	*mp,
1351 	char			*message)
1352 {
1353 	if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1354 	    xfs_readonly_buftarg(mp->m_logdev_targp) ||
1355 	    (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1356 		xfs_notice(mp, "%s required on read-only device.", message);
1357 		xfs_notice(mp, "write access unavailable, cannot proceed.");
1358 		return -EROFS;
1359 	}
1360 	return 0;
1361 }
1362 
1363 /* Force the summary counters to be recalculated at next mount. */
1364 void
1365 xfs_force_summary_recalc(
1366 	struct xfs_mount	*mp)
1367 {
1368 	if (!xfs_has_lazysbcount(mp))
1369 		return;
1370 
1371 	xfs_fs_mark_sick(mp, XFS_SICK_FS_COUNTERS);
1372 }
1373 
1374 /*
1375  * Enable a log incompat feature flag in the primary superblock.  The caller
1376  * cannot have any other transactions in progress.
1377  */
1378 int
1379 xfs_add_incompat_log_feature(
1380 	struct xfs_mount	*mp,
1381 	uint32_t		feature)
1382 {
1383 	struct xfs_dsb		*dsb;
1384 	int			error;
1385 
1386 	ASSERT(hweight32(feature) == 1);
1387 	ASSERT(!(feature & XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
1388 
1389 	/*
1390 	 * Force the log to disk and kick the background AIL thread to reduce
1391 	 * the chances that the bwrite will stall waiting for the AIL to unpin
1392 	 * the primary superblock buffer.  This isn't a data integrity
1393 	 * operation, so we don't need a synchronous push.
1394 	 */
1395 	error = xfs_log_force(mp, XFS_LOG_SYNC);
1396 	if (error)
1397 		return error;
1398 	xfs_ail_push_all(mp->m_ail);
1399 
1400 	/*
1401 	 * Lock the primary superblock buffer to serialize all callers that
1402 	 * are trying to set feature bits.
1403 	 */
1404 	xfs_buf_lock(mp->m_sb_bp);
1405 	xfs_buf_hold(mp->m_sb_bp);
1406 
1407 	if (xfs_is_shutdown(mp)) {
1408 		error = -EIO;
1409 		goto rele;
1410 	}
1411 
1412 	if (xfs_sb_has_incompat_log_feature(&mp->m_sb, feature))
1413 		goto rele;
1414 
1415 	/*
1416 	 * Write the primary superblock to disk immediately, because we need
1417 	 * the log_incompat bit to be set in the primary super now to protect
1418 	 * the log items that we're going to commit later.
1419 	 */
1420 	dsb = mp->m_sb_bp->b_addr;
1421 	xfs_sb_to_disk(dsb, &mp->m_sb);
1422 	dsb->sb_features_log_incompat |= cpu_to_be32(feature);
1423 	error = xfs_bwrite(mp->m_sb_bp);
1424 	if (error)
1425 		goto shutdown;
1426 
1427 	/*
1428 	 * Add the feature bits to the incore superblock before we unlock the
1429 	 * buffer.
1430 	 */
1431 	xfs_sb_add_incompat_log_features(&mp->m_sb, feature);
1432 	xfs_buf_relse(mp->m_sb_bp);
1433 
1434 	/* Log the superblock to disk. */
1435 	return xfs_sync_sb(mp, false);
1436 shutdown:
1437 	xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
1438 rele:
1439 	xfs_buf_relse(mp->m_sb_bp);
1440 	return error;
1441 }
1442 
1443 /*
1444  * Clear all the log incompat flags from the superblock.
1445  *
1446  * The caller cannot be in a transaction, must ensure that the log does not
1447  * contain any log items protected by any log incompat bit, and must ensure
1448  * that there are no other threads that depend on the state of the log incompat
1449  * feature flags in the primary super.
1450  *
1451  * Returns true if the superblock is dirty.
1452  */
1453 bool
1454 xfs_clear_incompat_log_features(
1455 	struct xfs_mount	*mp)
1456 {
1457 	bool			ret = false;
1458 
1459 	if (!xfs_has_crc(mp) ||
1460 	    !xfs_sb_has_incompat_log_feature(&mp->m_sb,
1461 				XFS_SB_FEAT_INCOMPAT_LOG_ALL) ||
1462 	    xfs_is_shutdown(mp) ||
1463 	    !xfs_is_done_with_log_incompat(mp))
1464 		return false;
1465 
1466 	/*
1467 	 * Update the incore superblock.  We synchronize on the primary super
1468 	 * buffer lock to be consistent with the add function, though at least
1469 	 * in theory this shouldn't be necessary.
1470 	 */
1471 	xfs_buf_lock(mp->m_sb_bp);
1472 	xfs_buf_hold(mp->m_sb_bp);
1473 
1474 	if (xfs_sb_has_incompat_log_feature(&mp->m_sb,
1475 				XFS_SB_FEAT_INCOMPAT_LOG_ALL)) {
1476 		xfs_sb_remove_incompat_log_features(&mp->m_sb);
1477 		ret = true;
1478 	}
1479 
1480 	xfs_buf_relse(mp->m_sb_bp);
1481 	return ret;
1482 }
1483 
1484 /*
1485  * Update the in-core delayed block counter.
1486  *
1487  * We prefer to update the counter without having to take a spinlock for every
1488  * counter update (i.e. batching).  Each change to delayed allocation
1489  * reservations can change can easily exceed the default percpu counter
1490  * batching, so we use a larger batch factor here.
1491  *
1492  * Note that we don't currently have any callers requiring fast summation
1493  * (e.g. percpu_counter_read) so we can use a big batch value here.
1494  */
1495 #define XFS_DELALLOC_BATCH	(4096)
1496 void
1497 xfs_mod_delalloc(
1498 	struct xfs_inode	*ip,
1499 	int64_t			data_delta,
1500 	int64_t			ind_delta)
1501 {
1502 	struct xfs_mount	*mp = ip->i_mount;
1503 
1504 	if (XFS_IS_REALTIME_INODE(ip)) {
1505 		percpu_counter_add_batch(&mp->m_delalloc_rtextents,
1506 				xfs_blen_to_rtbxlen(mp, data_delta),
1507 				XFS_DELALLOC_BATCH);
1508 		if (!ind_delta)
1509 			return;
1510 		data_delta = 0;
1511 	}
1512 	percpu_counter_add_batch(&mp->m_delalloc_blks, data_delta + ind_delta,
1513 			XFS_DELALLOC_BATCH);
1514 }
1515