1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2017-2023 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <djwong@kernel.org>
5 */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_trans_resv.h"
11 #include "xfs_mount.h"
12 #include "xfs_log_format.h"
13 #include "xfs_trans.h"
14 #include "xfs_inode.h"
15 #include "xfs_quota.h"
16 #include "xfs_qm.h"
17 #include "xfs_scrub.h"
18 #include "xfs_buf_mem.h"
19 #include "xfs_rmap.h"
20 #include "xfs_exchrange.h"
21 #include "xfs_exchmaps.h"
22 #include "xfs_dir2.h"
23 #include "xfs_parent.h"
24 #include "xfs_icache.h"
25 #include "scrub/scrub.h"
26 #include "scrub/common.h"
27 #include "scrub/trace.h"
28 #include "scrub/repair.h"
29 #include "scrub/health.h"
30 #include "scrub/stats.h"
31 #include "scrub/xfile.h"
32 #include "scrub/tempfile.h"
33 #include "scrub/orphanage.h"
34
35 /*
36 * Online Scrub and Repair
37 *
38 * Traditionally, XFS (the kernel driver) did not know how to check or
39 * repair on-disk data structures. That task was left to the xfs_check
40 * and xfs_repair tools, both of which require taking the filesystem
41 * offline for a thorough but time consuming examination. Online
42 * scrub & repair, on the other hand, enables us to check the metadata
43 * for obvious errors while carefully stepping around the filesystem's
44 * ongoing operations, locking rules, etc.
45 *
46 * Given that most XFS metadata consist of records stored in a btree,
47 * most of the checking functions iterate the btree blocks themselves
48 * looking for irregularities. When a record block is encountered, each
49 * record can be checked for obviously bad values. Record values can
50 * also be cross-referenced against other btrees to look for potential
51 * misunderstandings between pieces of metadata.
52 *
53 * It is expected that the checkers responsible for per-AG metadata
54 * structures will lock the AG headers (AGI, AGF, AGFL), iterate the
55 * metadata structure, and perform any relevant cross-referencing before
56 * unlocking the AG and returning the results to userspace. These
57 * scrubbers must not keep an AG locked for too long to avoid tying up
58 * the block and inode allocators.
59 *
60 * Block maps and b-trees rooted in an inode present a special challenge
61 * because they can involve extents from any AG. The general scrubber
62 * structure of lock -> check -> xref -> unlock still holds, but AG
63 * locking order rules /must/ be obeyed to avoid deadlocks. The
64 * ordering rule, of course, is that we must lock in increasing AG
65 * order. Helper functions are provided to track which AG headers we've
66 * already locked. If we detect an imminent locking order violation, we
67 * can signal a potential deadlock, in which case the scrubber can jump
68 * out to the top level, lock all the AGs in order, and retry the scrub.
69 *
70 * For file data (directories, extended attributes, symlinks) scrub, we
71 * can simply lock the inode and walk the data. For btree data
72 * (directories and attributes) we follow the same btree-scrubbing
73 * strategy outlined previously to check the records.
74 *
75 * We use a bit of trickery with transactions to avoid buffer deadlocks
76 * if there is a cycle in the metadata. The basic problem is that
77 * travelling down a btree involves locking the current buffer at each
78 * tree level. If a pointer should somehow point back to a buffer that
79 * we've already examined, we will deadlock due to the second buffer
80 * locking attempt. Note however that grabbing a buffer in transaction
81 * context links the locked buffer to the transaction. If we try to
82 * re-grab the buffer in the context of the same transaction, we avoid
83 * the second lock attempt and continue. Between the verifier and the
84 * scrubber, something will notice that something is amiss and report
85 * the corruption. Therefore, each scrubber will allocate an empty
86 * transaction, attach buffers to it, and cancel the transaction at the
87 * end of the scrub run. Cancelling a non-dirty transaction simply
88 * unlocks the buffers.
89 *
90 * There are four pieces of data that scrub can communicate to
91 * userspace. The first is the error code (errno), which can be used to
92 * communicate operational errors in performing the scrub. There are
93 * also three flags that can be set in the scrub context. If the data
94 * structure itself is corrupt, the CORRUPT flag will be set. If
95 * the metadata is correct but otherwise suboptimal, the PREEN flag
96 * will be set.
97 *
98 * We perform secondary validation of filesystem metadata by
99 * cross-referencing every record with all other available metadata.
100 * For example, for block mapping extents, we verify that there are no
101 * records in the free space and inode btrees corresponding to that
102 * space extent and that there is a corresponding entry in the reverse
103 * mapping btree. Inconsistent metadata is noted by setting the
104 * XCORRUPT flag; btree query function errors are noted by setting the
105 * XFAIL flag and deleting the cursor to prevent further attempts to
106 * cross-reference with a defective btree.
107 *
108 * If a piece of metadata proves corrupt or suboptimal, the userspace
109 * program can ask the kernel to apply some tender loving care (TLC) to
110 * the metadata object by setting the REPAIR flag and re-calling the
111 * scrub ioctl. "Corruption" is defined by metadata violating the
112 * on-disk specification; operations cannot continue if the violation is
113 * left untreated. It is possible for XFS to continue if an object is
114 * "suboptimal", however performance may be degraded. Repairs are
115 * usually performed by rebuilding the metadata entirely out of
116 * redundant metadata. Optimizing, on the other hand, can sometimes be
117 * done without rebuilding entire structures.
118 *
119 * Generally speaking, the repair code has the following code structure:
120 * Lock -> scrub -> repair -> commit -> re-lock -> re-scrub -> unlock.
121 * The first check helps us figure out if we need to rebuild or simply
122 * optimize the structure so that the rebuild knows what to do. The
123 * second check evaluates the completeness of the repair; that is what
124 * is reported to userspace.
125 *
126 * A quick note on symbol prefixes:
127 * - "xfs_" are general XFS symbols.
128 * - "xchk_" are symbols related to metadata checking.
129 * - "xrep_" are symbols related to metadata repair.
130 * - "xfs_scrub_" are symbols that tie online fsck to the rest of XFS.
131 */
132
133 /*
134 * Scrub probe -- userspace uses this to probe if we're willing to scrub
135 * or repair a given mountpoint. This will be used by xfs_scrub to
136 * probe the kernel's abilities to scrub (and repair) the metadata. We
137 * do this by validating the ioctl inputs from userspace, preparing the
138 * filesystem for a scrub (or a repair) operation, and immediately
139 * returning to userspace. Userspace can use the returned errno and
140 * structure state to decide (in broad terms) if scrub/repair are
141 * supported by the running kernel.
142 */
143 static int
xchk_probe(struct xfs_scrub * sc)144 xchk_probe(
145 struct xfs_scrub *sc)
146 {
147 int error = 0;
148
149 if (xchk_should_terminate(sc, &error))
150 return error;
151
152 return 0;
153 }
154
155 /* Scrub setup and teardown */
156
157 static inline void
xchk_fsgates_disable(struct xfs_scrub * sc)158 xchk_fsgates_disable(
159 struct xfs_scrub *sc)
160 {
161 if (!(sc->flags & XCHK_FSGATES_ALL))
162 return;
163
164 trace_xchk_fsgates_disable(sc, sc->flags & XCHK_FSGATES_ALL);
165
166 if (sc->flags & XCHK_FSGATES_DRAIN)
167 xfs_drain_wait_disable();
168
169 if (sc->flags & XCHK_FSGATES_QUOTA)
170 xfs_dqtrx_hook_disable();
171
172 if (sc->flags & XCHK_FSGATES_DIRENTS)
173 xfs_dir_hook_disable();
174
175 if (sc->flags & XCHK_FSGATES_RMAP)
176 xfs_rmap_hook_disable();
177
178 sc->flags &= ~XCHK_FSGATES_ALL;
179 }
180
181 /* Free the resources associated with a scrub subtype. */
182 void
xchk_scrub_free_subord(struct xfs_scrub_subord * sub)183 xchk_scrub_free_subord(
184 struct xfs_scrub_subord *sub)
185 {
186 struct xfs_scrub *sc = sub->parent_sc;
187
188 ASSERT(sc->ip == sub->sc.ip);
189 ASSERT(sc->orphanage == sub->sc.orphanage);
190 ASSERT(sc->tempip == sub->sc.tempip);
191
192 sc->sm->sm_type = sub->old_smtype;
193 sc->sm->sm_flags = sub->old_smflags |
194 (sc->sm->sm_flags & XFS_SCRUB_FLAGS_OUT);
195 sc->tp = sub->sc.tp;
196
197 if (sub->sc.buf) {
198 if (sub->sc.buf_cleanup)
199 sub->sc.buf_cleanup(sub->sc.buf);
200 kvfree(sub->sc.buf);
201 }
202 if (sub->sc.xmbtp)
203 xmbuf_free(sub->sc.xmbtp);
204 if (sub->sc.xfile)
205 xfile_destroy(sub->sc.xfile);
206
207 sc->ilock_flags = sub->sc.ilock_flags;
208 sc->orphanage_ilock_flags = sub->sc.orphanage_ilock_flags;
209 sc->temp_ilock_flags = sub->sc.temp_ilock_flags;
210
211 kfree(sub);
212 }
213
214 /* Free all the resources and finish the transactions. */
215 STATIC int
xchk_teardown(struct xfs_scrub * sc,int error)216 xchk_teardown(
217 struct xfs_scrub *sc,
218 int error)
219 {
220 xchk_ag_free(sc, &sc->sa);
221 if (sc->tp) {
222 if (error == 0 && (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
223 error = xfs_trans_commit(sc->tp);
224 else
225 xfs_trans_cancel(sc->tp);
226 sc->tp = NULL;
227 }
228 if (sc->ip) {
229 if (sc->ilock_flags)
230 xchk_iunlock(sc, sc->ilock_flags);
231 xchk_irele(sc, sc->ip);
232 sc->ip = NULL;
233 }
234 if (sc->flags & XCHK_HAVE_FREEZE_PROT) {
235 sc->flags &= ~XCHK_HAVE_FREEZE_PROT;
236 mnt_drop_write_file(sc->file);
237 }
238 if (sc->xmbtp) {
239 xmbuf_free(sc->xmbtp);
240 sc->xmbtp = NULL;
241 }
242 if (sc->xfile) {
243 xfile_destroy(sc->xfile);
244 sc->xfile = NULL;
245 }
246 if (sc->buf) {
247 if (sc->buf_cleanup)
248 sc->buf_cleanup(sc->buf);
249 kvfree(sc->buf);
250 sc->buf_cleanup = NULL;
251 sc->buf = NULL;
252 }
253
254 xrep_tempfile_rele(sc);
255 xrep_orphanage_rele(sc);
256 xchk_fsgates_disable(sc);
257 return error;
258 }
259
260 /* Scrubbing dispatch. */
261
262 static const struct xchk_meta_ops meta_scrub_ops[] = {
263 [XFS_SCRUB_TYPE_PROBE] = { /* ioctl presence test */
264 .type = ST_NONE,
265 .setup = xchk_setup_fs,
266 .scrub = xchk_probe,
267 .repair = xrep_probe,
268 },
269 [XFS_SCRUB_TYPE_SB] = { /* superblock */
270 .type = ST_PERAG,
271 .setup = xchk_setup_agheader,
272 .scrub = xchk_superblock,
273 .repair = xrep_superblock,
274 },
275 [XFS_SCRUB_TYPE_AGF] = { /* agf */
276 .type = ST_PERAG,
277 .setup = xchk_setup_agheader,
278 .scrub = xchk_agf,
279 .repair = xrep_agf,
280 },
281 [XFS_SCRUB_TYPE_AGFL]= { /* agfl */
282 .type = ST_PERAG,
283 .setup = xchk_setup_agheader,
284 .scrub = xchk_agfl,
285 .repair = xrep_agfl,
286 },
287 [XFS_SCRUB_TYPE_AGI] = { /* agi */
288 .type = ST_PERAG,
289 .setup = xchk_setup_agheader,
290 .scrub = xchk_agi,
291 .repair = xrep_agi,
292 },
293 [XFS_SCRUB_TYPE_BNOBT] = { /* bnobt */
294 .type = ST_PERAG,
295 .setup = xchk_setup_ag_allocbt,
296 .scrub = xchk_allocbt,
297 .repair = xrep_allocbt,
298 .repair_eval = xrep_revalidate_allocbt,
299 },
300 [XFS_SCRUB_TYPE_CNTBT] = { /* cntbt */
301 .type = ST_PERAG,
302 .setup = xchk_setup_ag_allocbt,
303 .scrub = xchk_allocbt,
304 .repair = xrep_allocbt,
305 .repair_eval = xrep_revalidate_allocbt,
306 },
307 [XFS_SCRUB_TYPE_INOBT] = { /* inobt */
308 .type = ST_PERAG,
309 .setup = xchk_setup_ag_iallocbt,
310 .scrub = xchk_iallocbt,
311 .repair = xrep_iallocbt,
312 .repair_eval = xrep_revalidate_iallocbt,
313 },
314 [XFS_SCRUB_TYPE_FINOBT] = { /* finobt */
315 .type = ST_PERAG,
316 .setup = xchk_setup_ag_iallocbt,
317 .scrub = xchk_iallocbt,
318 .has = xfs_has_finobt,
319 .repair = xrep_iallocbt,
320 .repair_eval = xrep_revalidate_iallocbt,
321 },
322 [XFS_SCRUB_TYPE_RMAPBT] = { /* rmapbt */
323 .type = ST_PERAG,
324 .setup = xchk_setup_ag_rmapbt,
325 .scrub = xchk_rmapbt,
326 .has = xfs_has_rmapbt,
327 .repair = xrep_rmapbt,
328 },
329 [XFS_SCRUB_TYPE_REFCNTBT] = { /* refcountbt */
330 .type = ST_PERAG,
331 .setup = xchk_setup_ag_refcountbt,
332 .scrub = xchk_refcountbt,
333 .has = xfs_has_reflink,
334 .repair = xrep_refcountbt,
335 },
336 [XFS_SCRUB_TYPE_INODE] = { /* inode record */
337 .type = ST_INODE,
338 .setup = xchk_setup_inode,
339 .scrub = xchk_inode,
340 .repair = xrep_inode,
341 },
342 [XFS_SCRUB_TYPE_BMBTD] = { /* inode data fork */
343 .type = ST_INODE,
344 .setup = xchk_setup_inode_bmap,
345 .scrub = xchk_bmap_data,
346 .repair = xrep_bmap_data,
347 },
348 [XFS_SCRUB_TYPE_BMBTA] = { /* inode attr fork */
349 .type = ST_INODE,
350 .setup = xchk_setup_inode_bmap,
351 .scrub = xchk_bmap_attr,
352 .repair = xrep_bmap_attr,
353 },
354 [XFS_SCRUB_TYPE_BMBTC] = { /* inode CoW fork */
355 .type = ST_INODE,
356 .setup = xchk_setup_inode_bmap,
357 .scrub = xchk_bmap_cow,
358 .repair = xrep_bmap_cow,
359 },
360 [XFS_SCRUB_TYPE_DIR] = { /* directory */
361 .type = ST_INODE,
362 .setup = xchk_setup_directory,
363 .scrub = xchk_directory,
364 .repair = xrep_directory,
365 },
366 [XFS_SCRUB_TYPE_XATTR] = { /* extended attributes */
367 .type = ST_INODE,
368 .setup = xchk_setup_xattr,
369 .scrub = xchk_xattr,
370 .repair = xrep_xattr,
371 },
372 [XFS_SCRUB_TYPE_SYMLINK] = { /* symbolic link */
373 .type = ST_INODE,
374 .setup = xchk_setup_symlink,
375 .scrub = xchk_symlink,
376 .repair = xrep_symlink,
377 },
378 [XFS_SCRUB_TYPE_PARENT] = { /* parent pointers */
379 .type = ST_INODE,
380 .setup = xchk_setup_parent,
381 .scrub = xchk_parent,
382 .repair = xrep_parent,
383 },
384 [XFS_SCRUB_TYPE_RTBITMAP] = { /* realtime bitmap */
385 .type = ST_FS,
386 .setup = xchk_setup_rtbitmap,
387 .scrub = xchk_rtbitmap,
388 .repair = xrep_rtbitmap,
389 },
390 [XFS_SCRUB_TYPE_RTSUM] = { /* realtime summary */
391 .type = ST_FS,
392 .setup = xchk_setup_rtsummary,
393 .scrub = xchk_rtsummary,
394 .repair = xrep_rtsummary,
395 },
396 [XFS_SCRUB_TYPE_UQUOTA] = { /* user quota */
397 .type = ST_FS,
398 .setup = xchk_setup_quota,
399 .scrub = xchk_quota,
400 .repair = xrep_quota,
401 },
402 [XFS_SCRUB_TYPE_GQUOTA] = { /* group quota */
403 .type = ST_FS,
404 .setup = xchk_setup_quota,
405 .scrub = xchk_quota,
406 .repair = xrep_quota,
407 },
408 [XFS_SCRUB_TYPE_PQUOTA] = { /* project quota */
409 .type = ST_FS,
410 .setup = xchk_setup_quota,
411 .scrub = xchk_quota,
412 .repair = xrep_quota,
413 },
414 [XFS_SCRUB_TYPE_FSCOUNTERS] = { /* fs summary counters */
415 .type = ST_FS,
416 .setup = xchk_setup_fscounters,
417 .scrub = xchk_fscounters,
418 .repair = xrep_fscounters,
419 },
420 [XFS_SCRUB_TYPE_QUOTACHECK] = { /* quota counters */
421 .type = ST_FS,
422 .setup = xchk_setup_quotacheck,
423 .scrub = xchk_quotacheck,
424 .repair = xrep_quotacheck,
425 },
426 [XFS_SCRUB_TYPE_NLINKS] = { /* inode link counts */
427 .type = ST_FS,
428 .setup = xchk_setup_nlinks,
429 .scrub = xchk_nlinks,
430 .repair = xrep_nlinks,
431 },
432 [XFS_SCRUB_TYPE_HEALTHY] = { /* fs healthy; clean all reminders */
433 .type = ST_FS,
434 .setup = xchk_setup_fs,
435 .scrub = xchk_health_record,
436 .repair = xrep_notsupported,
437 },
438 [XFS_SCRUB_TYPE_DIRTREE] = { /* directory tree structure */
439 .type = ST_INODE,
440 .setup = xchk_setup_dirtree,
441 .scrub = xchk_dirtree,
442 .has = xfs_has_parent,
443 .repair = xrep_dirtree,
444 },
445 };
446
447 static int
xchk_validate_inputs(struct xfs_mount * mp,struct xfs_scrub_metadata * sm)448 xchk_validate_inputs(
449 struct xfs_mount *mp,
450 struct xfs_scrub_metadata *sm)
451 {
452 int error;
453 const struct xchk_meta_ops *ops;
454
455 error = -EINVAL;
456 /* Check our inputs. */
457 sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
458 if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN)
459 goto out;
460 /* sm_reserved[] must be zero */
461 if (memchr_inv(sm->sm_reserved, 0, sizeof(sm->sm_reserved)))
462 goto out;
463
464 error = -ENOENT;
465 /* Do we know about this type of metadata? */
466 if (sm->sm_type >= XFS_SCRUB_TYPE_NR)
467 goto out;
468 ops = &meta_scrub_ops[sm->sm_type];
469 if (ops->setup == NULL || ops->scrub == NULL)
470 goto out;
471 /* Does this fs even support this type of metadata? */
472 if (ops->has && !ops->has(mp))
473 goto out;
474
475 error = -EINVAL;
476 /* restricting fields must be appropriate for type */
477 switch (ops->type) {
478 case ST_NONE:
479 case ST_FS:
480 if (sm->sm_ino || sm->sm_gen || sm->sm_agno)
481 goto out;
482 break;
483 case ST_PERAG:
484 if (sm->sm_ino || sm->sm_gen ||
485 sm->sm_agno >= mp->m_sb.sb_agcount)
486 goto out;
487 break;
488 case ST_INODE:
489 if (sm->sm_agno || (sm->sm_gen && !sm->sm_ino))
490 goto out;
491 break;
492 default:
493 goto out;
494 }
495
496 /* No rebuild without repair. */
497 if ((sm->sm_flags & XFS_SCRUB_IFLAG_FORCE_REBUILD) &&
498 !(sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
499 return -EINVAL;
500
501 /*
502 * We only want to repair read-write v5+ filesystems. Defer the check
503 * for ops->repair until after our scrub confirms that we need to
504 * perform repairs so that we avoid failing due to not supporting
505 * repairing an object that doesn't need repairs.
506 */
507 if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
508 error = -EOPNOTSUPP;
509 if (!xfs_has_crc(mp))
510 goto out;
511
512 error = -EROFS;
513 if (xfs_is_readonly(mp))
514 goto out;
515 }
516
517 error = 0;
518 out:
519 return error;
520 }
521
522 #ifdef CONFIG_XFS_ONLINE_REPAIR
xchk_postmortem(struct xfs_scrub * sc)523 static inline void xchk_postmortem(struct xfs_scrub *sc)
524 {
525 /*
526 * Userspace asked us to repair something, we repaired it, rescanned
527 * it, and the rescan says it's still broken. Scream about this in
528 * the system logs.
529 */
530 if ((sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) &&
531 (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
532 XFS_SCRUB_OFLAG_XCORRUPT)))
533 xrep_failure(sc->mp);
534 }
535 #else
xchk_postmortem(struct xfs_scrub * sc)536 static inline void xchk_postmortem(struct xfs_scrub *sc)
537 {
538 /*
539 * Userspace asked us to scrub something, it's broken, and we have no
540 * way of fixing it. Scream in the logs.
541 */
542 if (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
543 XFS_SCRUB_OFLAG_XCORRUPT))
544 xfs_alert_ratelimited(sc->mp,
545 "Corruption detected during scrub.");
546 }
547 #endif /* CONFIG_XFS_ONLINE_REPAIR */
548
549 /*
550 * Create a new scrub context from an existing one, but with a different scrub
551 * type.
552 */
553 struct xfs_scrub_subord *
xchk_scrub_create_subord(struct xfs_scrub * sc,unsigned int subtype)554 xchk_scrub_create_subord(
555 struct xfs_scrub *sc,
556 unsigned int subtype)
557 {
558 struct xfs_scrub_subord *sub;
559
560 sub = kzalloc(sizeof(*sub), XCHK_GFP_FLAGS);
561 if (!sub)
562 return ERR_PTR(-ENOMEM);
563
564 sub->old_smtype = sc->sm->sm_type;
565 sub->old_smflags = sc->sm->sm_flags;
566 sub->parent_sc = sc;
567 memcpy(&sub->sc, sc, sizeof(struct xfs_scrub));
568 sub->sc.ops = &meta_scrub_ops[subtype];
569 sub->sc.sm->sm_type = subtype;
570 sub->sc.sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
571 sub->sc.buf = NULL;
572 sub->sc.buf_cleanup = NULL;
573 sub->sc.xfile = NULL;
574 sub->sc.xmbtp = NULL;
575
576 return sub;
577 }
578
579 /* Dispatch metadata scrubbing. */
580 STATIC int
xfs_scrub_metadata(struct file * file,struct xfs_scrub_metadata * sm)581 xfs_scrub_metadata(
582 struct file *file,
583 struct xfs_scrub_metadata *sm)
584 {
585 struct xchk_stats_run run = { };
586 struct xfs_scrub *sc;
587 struct xfs_mount *mp = XFS_I(file_inode(file))->i_mount;
588 u64 check_start;
589 int error = 0;
590
591 BUILD_BUG_ON(sizeof(meta_scrub_ops) !=
592 (sizeof(struct xchk_meta_ops) * XFS_SCRUB_TYPE_NR));
593
594 trace_xchk_start(XFS_I(file_inode(file)), sm, error);
595
596 /* Forbidden if we are shut down or mounted norecovery. */
597 error = -ESHUTDOWN;
598 if (xfs_is_shutdown(mp))
599 goto out;
600 error = -ENOTRECOVERABLE;
601 if (xfs_has_norecovery(mp))
602 goto out;
603
604 error = xchk_validate_inputs(mp, sm);
605 if (error)
606 goto out;
607
608 xfs_warn_mount(mp, XFS_OPSTATE_WARNED_SCRUB,
609 "EXPERIMENTAL online scrub feature in use. Use at your own risk!");
610
611 sc = kzalloc(sizeof(struct xfs_scrub), XCHK_GFP_FLAGS);
612 if (!sc) {
613 error = -ENOMEM;
614 goto out;
615 }
616
617 sc->mp = mp;
618 sc->file = file;
619 sc->sm = sm;
620 sc->ops = &meta_scrub_ops[sm->sm_type];
621 sc->sick_mask = xchk_health_mask_for_scrub_type(sm->sm_type);
622 sc->relax = INIT_XCHK_RELAX;
623 retry_op:
624 /*
625 * When repairs are allowed, prevent freezing or readonly remount while
626 * scrub is running with a real transaction.
627 */
628 if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
629 error = mnt_want_write_file(sc->file);
630 if (error)
631 goto out_sc;
632
633 sc->flags |= XCHK_HAVE_FREEZE_PROT;
634 }
635
636 /* Set up for the operation. */
637 error = sc->ops->setup(sc);
638 if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER))
639 goto try_harder;
640 if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN))
641 goto need_drain;
642 if (error)
643 goto out_teardown;
644
645 /* Scrub for errors. */
646 check_start = xchk_stats_now();
647 if ((sc->flags & XREP_ALREADY_FIXED) && sc->ops->repair_eval != NULL)
648 error = sc->ops->repair_eval(sc);
649 else
650 error = sc->ops->scrub(sc);
651 run.scrub_ns += xchk_stats_elapsed_ns(check_start);
652 if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER))
653 goto try_harder;
654 if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN))
655 goto need_drain;
656 if (error || (sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE))
657 goto out_teardown;
658
659 xchk_update_health(sc);
660
661 if (xchk_could_repair(sc)) {
662 /*
663 * If userspace asked for a repair but it wasn't necessary,
664 * report that back to userspace.
665 */
666 if (!xrep_will_attempt(sc)) {
667 sc->sm->sm_flags |= XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED;
668 goto out_nofix;
669 }
670
671 /*
672 * If it's broken, userspace wants us to fix it, and we haven't
673 * already tried to fix it, then attempt a repair.
674 */
675 error = xrep_attempt(sc, &run);
676 if (error == -EAGAIN) {
677 /*
678 * Either the repair function succeeded or it couldn't
679 * get all the resources it needs; either way, we go
680 * back to the beginning and call the scrub function.
681 */
682 error = xchk_teardown(sc, 0);
683 if (error) {
684 xrep_failure(mp);
685 goto out_sc;
686 }
687 goto retry_op;
688 }
689 }
690
691 out_nofix:
692 xchk_postmortem(sc);
693 out_teardown:
694 error = xchk_teardown(sc, error);
695 out_sc:
696 if (error != -ENOENT)
697 xchk_stats_merge(mp, sm, &run);
698 kfree(sc);
699 out:
700 trace_xchk_done(XFS_I(file_inode(file)), sm, error);
701 if (error == -EFSCORRUPTED || error == -EFSBADCRC) {
702 sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
703 error = 0;
704 }
705 return error;
706 need_drain:
707 error = xchk_teardown(sc, 0);
708 if (error)
709 goto out_sc;
710 sc->flags |= XCHK_NEED_DRAIN;
711 run.retries++;
712 goto retry_op;
713 try_harder:
714 /*
715 * Scrubbers return -EDEADLOCK to mean 'try harder'. Tear down
716 * everything we hold, then set up again with preparation for
717 * worst-case scenarios.
718 */
719 error = xchk_teardown(sc, 0);
720 if (error)
721 goto out_sc;
722 sc->flags |= XCHK_TRY_HARDER;
723 run.retries++;
724 goto retry_op;
725 }
726
727 /* Scrub one aspect of one piece of metadata. */
728 int
xfs_ioc_scrub_metadata(struct file * file,void __user * arg)729 xfs_ioc_scrub_metadata(
730 struct file *file,
731 void __user *arg)
732 {
733 struct xfs_scrub_metadata scrub;
734 int error;
735
736 if (!capable(CAP_SYS_ADMIN))
737 return -EPERM;
738
739 if (copy_from_user(&scrub, arg, sizeof(scrub)))
740 return -EFAULT;
741
742 error = xfs_scrub_metadata(file, &scrub);
743 if (error)
744 return error;
745
746 if (copy_to_user(arg, &scrub, sizeof(scrub)))
747 return -EFAULT;
748
749 return 0;
750 }
751
752 /* Decide if there have been any scrub failures up to this point. */
753 static inline int
xfs_scrubv_check_barrier(struct xfs_mount * mp,const struct xfs_scrub_vec * vectors,const struct xfs_scrub_vec * stop_vec)754 xfs_scrubv_check_barrier(
755 struct xfs_mount *mp,
756 const struct xfs_scrub_vec *vectors,
757 const struct xfs_scrub_vec *stop_vec)
758 {
759 const struct xfs_scrub_vec *v;
760 __u32 failmask;
761
762 failmask = stop_vec->sv_flags & XFS_SCRUB_FLAGS_OUT;
763
764 for (v = vectors; v < stop_vec; v++) {
765 if (v->sv_type == XFS_SCRUB_TYPE_BARRIER)
766 continue;
767
768 /*
769 * Runtime errors count as a previous failure, except the ones
770 * used to ask userspace to retry.
771 */
772 switch (v->sv_ret) {
773 case -EBUSY:
774 case -ENOENT:
775 case -EUSERS:
776 case 0:
777 break;
778 default:
779 return -ECANCELED;
780 }
781
782 /*
783 * If any of the out-flags on the scrub vector match the mask
784 * that was set on the barrier vector, that's a previous fail.
785 */
786 if (v->sv_flags & failmask)
787 return -ECANCELED;
788 }
789
790 return 0;
791 }
792
793 /*
794 * If the caller provided us with a nonzero inode number that isn't the ioctl
795 * file, try to grab a reference to it to eliminate all further untrusted inode
796 * lookups. If we can't get the inode, let each scrub function try again.
797 */
798 STATIC struct xfs_inode *
xchk_scrubv_open_by_handle(struct xfs_mount * mp,const struct xfs_scrub_vec_head * head)799 xchk_scrubv_open_by_handle(
800 struct xfs_mount *mp,
801 const struct xfs_scrub_vec_head *head)
802 {
803 struct xfs_trans *tp;
804 struct xfs_inode *ip;
805 int error;
806
807 error = xfs_trans_alloc_empty(mp, &tp);
808 if (error)
809 return NULL;
810
811 error = xfs_iget(mp, tp, head->svh_ino, XCHK_IGET_FLAGS, 0, &ip);
812 xfs_trans_cancel(tp);
813 if (error)
814 return NULL;
815
816 if (VFS_I(ip)->i_generation != head->svh_gen) {
817 xfs_irele(ip);
818 return NULL;
819 }
820
821 return ip;
822 }
823
824 /* Vectored scrub implementation to reduce ioctl calls. */
825 int
xfs_ioc_scrubv_metadata(struct file * file,void __user * arg)826 xfs_ioc_scrubv_metadata(
827 struct file *file,
828 void __user *arg)
829 {
830 struct xfs_scrub_vec_head head;
831 struct xfs_scrub_vec_head __user *uhead = arg;
832 struct xfs_scrub_vec *vectors;
833 struct xfs_scrub_vec __user *uvectors;
834 struct xfs_inode *ip_in = XFS_I(file_inode(file));
835 struct xfs_mount *mp = ip_in->i_mount;
836 struct xfs_inode *handle_ip = NULL;
837 struct xfs_scrub_vec *v;
838 size_t vec_bytes;
839 unsigned int i;
840 int error = 0;
841
842 if (!capable(CAP_SYS_ADMIN))
843 return -EPERM;
844
845 if (copy_from_user(&head, uhead, sizeof(head)))
846 return -EFAULT;
847
848 if (head.svh_reserved)
849 return -EINVAL;
850 if (head.svh_flags & ~XFS_SCRUB_VEC_FLAGS_ALL)
851 return -EINVAL;
852 if (head.svh_nr == 0)
853 return 0;
854
855 vec_bytes = array_size(head.svh_nr, sizeof(struct xfs_scrub_vec));
856 if (vec_bytes > PAGE_SIZE)
857 return -ENOMEM;
858
859 uvectors = u64_to_user_ptr(head.svh_vectors);
860 vectors = memdup_user(uvectors, vec_bytes);
861 if (IS_ERR(vectors))
862 return PTR_ERR(vectors);
863
864 trace_xchk_scrubv_start(ip_in, &head);
865
866 for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
867 if (v->sv_reserved) {
868 error = -EINVAL;
869 goto out_free;
870 }
871
872 if (v->sv_type == XFS_SCRUB_TYPE_BARRIER &&
873 (v->sv_flags & ~XFS_SCRUB_FLAGS_OUT)) {
874 error = -EINVAL;
875 goto out_free;
876 }
877
878 trace_xchk_scrubv_item(mp, &head, i, v);
879 }
880
881 /*
882 * If the caller wants us to do a scrub-by-handle and the file used to
883 * call the ioctl is not the same file, load the incore inode and pin
884 * it across all the scrubv actions to avoid repeated UNTRUSTED
885 * lookups. The reference is not passed to deeper layers of scrub
886 * because each scrubber gets to decide its own strategy and return
887 * values for getting an inode.
888 */
889 if (head.svh_ino && head.svh_ino != ip_in->i_ino)
890 handle_ip = xchk_scrubv_open_by_handle(mp, &head);
891
892 /* Run all the scrubbers. */
893 for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
894 struct xfs_scrub_metadata sm = {
895 .sm_type = v->sv_type,
896 .sm_flags = v->sv_flags,
897 .sm_ino = head.svh_ino,
898 .sm_gen = head.svh_gen,
899 .sm_agno = head.svh_agno,
900 };
901
902 if (v->sv_type == XFS_SCRUB_TYPE_BARRIER) {
903 v->sv_ret = xfs_scrubv_check_barrier(mp, vectors, v);
904 if (v->sv_ret) {
905 trace_xchk_scrubv_barrier_fail(mp, &head, i, v);
906 break;
907 }
908
909 continue;
910 }
911
912 v->sv_ret = xfs_scrub_metadata(file, &sm);
913 v->sv_flags = sm.sm_flags;
914
915 trace_xchk_scrubv_outcome(mp, &head, i, v);
916
917 if (head.svh_rest_us) {
918 ktime_t expires;
919
920 expires = ktime_add_ns(ktime_get(),
921 head.svh_rest_us * 1000);
922 set_current_state(TASK_KILLABLE);
923 schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
924 }
925
926 if (fatal_signal_pending(current)) {
927 error = -EINTR;
928 goto out_free;
929 }
930 }
931
932 if (copy_to_user(uvectors, vectors, vec_bytes) ||
933 copy_to_user(uhead, &head, sizeof(head))) {
934 error = -EFAULT;
935 goto out_free;
936 }
937
938 out_free:
939 if (handle_ip)
940 xfs_irele(handle_ip);
941 kfree(vectors);
942 return error;
943 }
944