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 /*
153 * If the caller is probing to see if repair works but repair isn't
154 * built into the kernel, return EOPNOTSUPP because that's the signal
155 * that userspace expects. If online repair is built in, set the
156 * CORRUPT flag (without any of the usual tracing/logging) to force us
157 * into xrep_probe.
158 */
159 if (xchk_could_repair(sc)) {
160 if (!IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR))
161 return -EOPNOTSUPP;
162 sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
163 }
164 return 0;
165 }
166
167 /* Scrub setup and teardown */
168
169 static inline void
xchk_fsgates_disable(struct xfs_scrub * sc)170 xchk_fsgates_disable(
171 struct xfs_scrub *sc)
172 {
173 if (!(sc->flags & XCHK_FSGATES_ALL))
174 return;
175
176 trace_xchk_fsgates_disable(sc, sc->flags & XCHK_FSGATES_ALL);
177
178 if (sc->flags & XCHK_FSGATES_DRAIN)
179 xfs_drain_wait_disable();
180
181 if (sc->flags & XCHK_FSGATES_QUOTA)
182 xfs_dqtrx_hook_disable();
183
184 if (sc->flags & XCHK_FSGATES_DIRENTS)
185 xfs_dir_hook_disable();
186
187 if (sc->flags & XCHK_FSGATES_RMAP)
188 xfs_rmap_hook_disable();
189
190 sc->flags &= ~XCHK_FSGATES_ALL;
191 }
192
193 /* Free the resources associated with a scrub subtype. */
194 void
xchk_scrub_free_subord(struct xfs_scrub_subord * sub)195 xchk_scrub_free_subord(
196 struct xfs_scrub_subord *sub)
197 {
198 struct xfs_scrub *sc = sub->parent_sc;
199
200 ASSERT(sc->ip == sub->sc.ip);
201 ASSERT(sc->orphanage == sub->sc.orphanage);
202 ASSERT(sc->tempip == sub->sc.tempip);
203
204 sc->sm->sm_type = sub->old_smtype;
205 sc->sm->sm_flags = sub->old_smflags |
206 (sc->sm->sm_flags & XFS_SCRUB_FLAGS_OUT);
207 sc->tp = sub->sc.tp;
208
209 if (sub->sc.buf) {
210 if (sub->sc.buf_cleanup)
211 sub->sc.buf_cleanup(sub->sc.buf);
212 kvfree(sub->sc.buf);
213 }
214 if (sub->sc.xmbtp)
215 xmbuf_free(sub->sc.xmbtp);
216 if (sub->sc.xfile)
217 xfile_destroy(sub->sc.xfile);
218
219 sc->ilock_flags = sub->sc.ilock_flags;
220 sc->orphanage_ilock_flags = sub->sc.orphanage_ilock_flags;
221 sc->temp_ilock_flags = sub->sc.temp_ilock_flags;
222
223 kfree(sub);
224 }
225
226 /* Free all the resources and finish the transactions. */
227 STATIC int
xchk_teardown(struct xfs_scrub * sc,int error)228 xchk_teardown(
229 struct xfs_scrub *sc,
230 int error)
231 {
232 xchk_ag_free(sc, &sc->sa);
233 if (sc->tp) {
234 if (error == 0 && (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
235 error = xfs_trans_commit(sc->tp);
236 else
237 xfs_trans_cancel(sc->tp);
238 sc->tp = NULL;
239 }
240 if (sc->ip) {
241 if (sc->ilock_flags)
242 xchk_iunlock(sc, sc->ilock_flags);
243 xchk_irele(sc, sc->ip);
244 sc->ip = NULL;
245 }
246 if (sc->flags & XCHK_HAVE_FREEZE_PROT) {
247 sc->flags &= ~XCHK_HAVE_FREEZE_PROT;
248 mnt_drop_write_file(sc->file);
249 }
250 if (sc->xmbtp) {
251 xmbuf_free(sc->xmbtp);
252 sc->xmbtp = NULL;
253 }
254 if (sc->xfile) {
255 xfile_destroy(sc->xfile);
256 sc->xfile = NULL;
257 }
258 if (sc->buf) {
259 if (sc->buf_cleanup)
260 sc->buf_cleanup(sc->buf);
261 kvfree(sc->buf);
262 sc->buf_cleanup = NULL;
263 sc->buf = NULL;
264 }
265
266 xrep_tempfile_rele(sc);
267 xrep_orphanage_rele(sc);
268 xchk_fsgates_disable(sc);
269 return error;
270 }
271
272 /* Scrubbing dispatch. */
273
274 static const struct xchk_meta_ops meta_scrub_ops[] = {
275 [XFS_SCRUB_TYPE_PROBE] = { /* ioctl presence test */
276 .type = ST_NONE,
277 .setup = xchk_setup_fs,
278 .scrub = xchk_probe,
279 .repair = xrep_probe,
280 },
281 [XFS_SCRUB_TYPE_SB] = { /* superblock */
282 .type = ST_PERAG,
283 .setup = xchk_setup_agheader,
284 .scrub = xchk_superblock,
285 .repair = xrep_superblock,
286 },
287 [XFS_SCRUB_TYPE_AGF] = { /* agf */
288 .type = ST_PERAG,
289 .setup = xchk_setup_agheader,
290 .scrub = xchk_agf,
291 .repair = xrep_agf,
292 },
293 [XFS_SCRUB_TYPE_AGFL]= { /* agfl */
294 .type = ST_PERAG,
295 .setup = xchk_setup_agheader,
296 .scrub = xchk_agfl,
297 .repair = xrep_agfl,
298 },
299 [XFS_SCRUB_TYPE_AGI] = { /* agi */
300 .type = ST_PERAG,
301 .setup = xchk_setup_agheader,
302 .scrub = xchk_agi,
303 .repair = xrep_agi,
304 },
305 [XFS_SCRUB_TYPE_BNOBT] = { /* bnobt */
306 .type = ST_PERAG,
307 .setup = xchk_setup_ag_allocbt,
308 .scrub = xchk_allocbt,
309 .repair = xrep_allocbt,
310 .repair_eval = xrep_revalidate_allocbt,
311 },
312 [XFS_SCRUB_TYPE_CNTBT] = { /* cntbt */
313 .type = ST_PERAG,
314 .setup = xchk_setup_ag_allocbt,
315 .scrub = xchk_allocbt,
316 .repair = xrep_allocbt,
317 .repair_eval = xrep_revalidate_allocbt,
318 },
319 [XFS_SCRUB_TYPE_INOBT] = { /* inobt */
320 .type = ST_PERAG,
321 .setup = xchk_setup_ag_iallocbt,
322 .scrub = xchk_iallocbt,
323 .repair = xrep_iallocbt,
324 .repair_eval = xrep_revalidate_iallocbt,
325 },
326 [XFS_SCRUB_TYPE_FINOBT] = { /* finobt */
327 .type = ST_PERAG,
328 .setup = xchk_setup_ag_iallocbt,
329 .scrub = xchk_iallocbt,
330 .has = xfs_has_finobt,
331 .repair = xrep_iallocbt,
332 .repair_eval = xrep_revalidate_iallocbt,
333 },
334 [XFS_SCRUB_TYPE_RMAPBT] = { /* rmapbt */
335 .type = ST_PERAG,
336 .setup = xchk_setup_ag_rmapbt,
337 .scrub = xchk_rmapbt,
338 .has = xfs_has_rmapbt,
339 .repair = xrep_rmapbt,
340 },
341 [XFS_SCRUB_TYPE_REFCNTBT] = { /* refcountbt */
342 .type = ST_PERAG,
343 .setup = xchk_setup_ag_refcountbt,
344 .scrub = xchk_refcountbt,
345 .has = xfs_has_reflink,
346 .repair = xrep_refcountbt,
347 },
348 [XFS_SCRUB_TYPE_INODE] = { /* inode record */
349 .type = ST_INODE,
350 .setup = xchk_setup_inode,
351 .scrub = xchk_inode,
352 .repair = xrep_inode,
353 },
354 [XFS_SCRUB_TYPE_BMBTD] = { /* inode data fork */
355 .type = ST_INODE,
356 .setup = xchk_setup_inode_bmap,
357 .scrub = xchk_bmap_data,
358 .repair = xrep_bmap_data,
359 },
360 [XFS_SCRUB_TYPE_BMBTA] = { /* inode attr fork */
361 .type = ST_INODE,
362 .setup = xchk_setup_inode_bmap,
363 .scrub = xchk_bmap_attr,
364 .repair = xrep_bmap_attr,
365 },
366 [XFS_SCRUB_TYPE_BMBTC] = { /* inode CoW fork */
367 .type = ST_INODE,
368 .setup = xchk_setup_inode_bmap,
369 .scrub = xchk_bmap_cow,
370 .repair = xrep_bmap_cow,
371 },
372 [XFS_SCRUB_TYPE_DIR] = { /* directory */
373 .type = ST_INODE,
374 .setup = xchk_setup_directory,
375 .scrub = xchk_directory,
376 .repair = xrep_directory,
377 },
378 [XFS_SCRUB_TYPE_XATTR] = { /* extended attributes */
379 .type = ST_INODE,
380 .setup = xchk_setup_xattr,
381 .scrub = xchk_xattr,
382 .repair = xrep_xattr,
383 },
384 [XFS_SCRUB_TYPE_SYMLINK] = { /* symbolic link */
385 .type = ST_INODE,
386 .setup = xchk_setup_symlink,
387 .scrub = xchk_symlink,
388 .repair = xrep_symlink,
389 },
390 [XFS_SCRUB_TYPE_PARENT] = { /* parent pointers */
391 .type = ST_INODE,
392 .setup = xchk_setup_parent,
393 .scrub = xchk_parent,
394 .repair = xrep_parent,
395 },
396 [XFS_SCRUB_TYPE_RTBITMAP] = { /* realtime bitmap */
397 .type = ST_FS,
398 .setup = xchk_setup_rtbitmap,
399 .scrub = xchk_rtbitmap,
400 .repair = xrep_rtbitmap,
401 },
402 [XFS_SCRUB_TYPE_RTSUM] = { /* realtime summary */
403 .type = ST_FS,
404 .setup = xchk_setup_rtsummary,
405 .scrub = xchk_rtsummary,
406 .repair = xrep_rtsummary,
407 },
408 [XFS_SCRUB_TYPE_UQUOTA] = { /* user quota */
409 .type = ST_FS,
410 .setup = xchk_setup_quota,
411 .scrub = xchk_quota,
412 .repair = xrep_quota,
413 },
414 [XFS_SCRUB_TYPE_GQUOTA] = { /* group quota */
415 .type = ST_FS,
416 .setup = xchk_setup_quota,
417 .scrub = xchk_quota,
418 .repair = xrep_quota,
419 },
420 [XFS_SCRUB_TYPE_PQUOTA] = { /* project quota */
421 .type = ST_FS,
422 .setup = xchk_setup_quota,
423 .scrub = xchk_quota,
424 .repair = xrep_quota,
425 },
426 [XFS_SCRUB_TYPE_FSCOUNTERS] = { /* fs summary counters */
427 .type = ST_FS,
428 .setup = xchk_setup_fscounters,
429 .scrub = xchk_fscounters,
430 .repair = xrep_fscounters,
431 },
432 [XFS_SCRUB_TYPE_QUOTACHECK] = { /* quota counters */
433 .type = ST_FS,
434 .setup = xchk_setup_quotacheck,
435 .scrub = xchk_quotacheck,
436 .repair = xrep_quotacheck,
437 },
438 [XFS_SCRUB_TYPE_NLINKS] = { /* inode link counts */
439 .type = ST_FS,
440 .setup = xchk_setup_nlinks,
441 .scrub = xchk_nlinks,
442 .repair = xrep_nlinks,
443 },
444 [XFS_SCRUB_TYPE_HEALTHY] = { /* fs healthy; clean all reminders */
445 .type = ST_FS,
446 .setup = xchk_setup_fs,
447 .scrub = xchk_health_record,
448 .repair = xrep_notsupported,
449 },
450 [XFS_SCRUB_TYPE_DIRTREE] = { /* directory tree structure */
451 .type = ST_INODE,
452 .setup = xchk_setup_dirtree,
453 .scrub = xchk_dirtree,
454 .has = xfs_has_parent,
455 .repair = xrep_dirtree,
456 },
457 };
458
459 static int
xchk_validate_inputs(struct xfs_mount * mp,struct xfs_scrub_metadata * sm)460 xchk_validate_inputs(
461 struct xfs_mount *mp,
462 struct xfs_scrub_metadata *sm)
463 {
464 int error;
465 const struct xchk_meta_ops *ops;
466
467 error = -EINVAL;
468 /* Check our inputs. */
469 sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
470 if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN)
471 goto out;
472 /* sm_reserved[] must be zero */
473 if (memchr_inv(sm->sm_reserved, 0, sizeof(sm->sm_reserved)))
474 goto out;
475
476 error = -ENOENT;
477 /* Do we know about this type of metadata? */
478 if (sm->sm_type >= XFS_SCRUB_TYPE_NR)
479 goto out;
480 ops = &meta_scrub_ops[sm->sm_type];
481 if (ops->setup == NULL || ops->scrub == NULL)
482 goto out;
483 /* Does this fs even support this type of metadata? */
484 if (ops->has && !ops->has(mp))
485 goto out;
486
487 error = -EINVAL;
488 /* restricting fields must be appropriate for type */
489 switch (ops->type) {
490 case ST_NONE:
491 case ST_FS:
492 if (sm->sm_ino || sm->sm_gen || sm->sm_agno)
493 goto out;
494 break;
495 case ST_PERAG:
496 if (sm->sm_ino || sm->sm_gen ||
497 sm->sm_agno >= mp->m_sb.sb_agcount)
498 goto out;
499 break;
500 case ST_INODE:
501 if (sm->sm_agno || (sm->sm_gen && !sm->sm_ino))
502 goto out;
503 break;
504 default:
505 goto out;
506 }
507
508 /* No rebuild without repair. */
509 if ((sm->sm_flags & XFS_SCRUB_IFLAG_FORCE_REBUILD) &&
510 !(sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
511 return -EINVAL;
512
513 /*
514 * We only want to repair read-write v5+ filesystems. Defer the check
515 * for ops->repair until after our scrub confirms that we need to
516 * perform repairs so that we avoid failing due to not supporting
517 * repairing an object that doesn't need repairs.
518 */
519 if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
520 error = -EOPNOTSUPP;
521 if (!xfs_has_crc(mp))
522 goto out;
523
524 error = -EROFS;
525 if (xfs_is_readonly(mp))
526 goto out;
527 }
528
529 error = 0;
530 out:
531 return error;
532 }
533
534 #ifdef CONFIG_XFS_ONLINE_REPAIR
xchk_postmortem(struct xfs_scrub * sc)535 static inline void xchk_postmortem(struct xfs_scrub *sc)
536 {
537 /*
538 * Userspace asked us to repair something, we repaired it, rescanned
539 * it, and the rescan says it's still broken. Scream about this in
540 * the system logs.
541 */
542 if ((sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) &&
543 (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
544 XFS_SCRUB_OFLAG_XCORRUPT)))
545 xrep_failure(sc->mp);
546 }
547 #else
xchk_postmortem(struct xfs_scrub * sc)548 static inline void xchk_postmortem(struct xfs_scrub *sc)
549 {
550 /*
551 * Userspace asked us to scrub something, it's broken, and we have no
552 * way of fixing it. Scream in the logs.
553 */
554 if (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
555 XFS_SCRUB_OFLAG_XCORRUPT))
556 xfs_alert_ratelimited(sc->mp,
557 "Corruption detected during scrub.");
558 }
559 #endif /* CONFIG_XFS_ONLINE_REPAIR */
560
561 /*
562 * Create a new scrub context from an existing one, but with a different scrub
563 * type.
564 */
565 struct xfs_scrub_subord *
xchk_scrub_create_subord(struct xfs_scrub * sc,unsigned int subtype)566 xchk_scrub_create_subord(
567 struct xfs_scrub *sc,
568 unsigned int subtype)
569 {
570 struct xfs_scrub_subord *sub;
571
572 sub = kzalloc(sizeof(*sub), XCHK_GFP_FLAGS);
573 if (!sub)
574 return ERR_PTR(-ENOMEM);
575
576 sub->old_smtype = sc->sm->sm_type;
577 sub->old_smflags = sc->sm->sm_flags;
578 sub->parent_sc = sc;
579 memcpy(&sub->sc, sc, sizeof(struct xfs_scrub));
580 sub->sc.ops = &meta_scrub_ops[subtype];
581 sub->sc.sm->sm_type = subtype;
582 sub->sc.sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
583 sub->sc.buf = NULL;
584 sub->sc.buf_cleanup = NULL;
585 sub->sc.xfile = NULL;
586 sub->sc.xmbtp = NULL;
587
588 return sub;
589 }
590
591 /* Dispatch metadata scrubbing. */
592 STATIC int
xfs_scrub_metadata(struct file * file,struct xfs_scrub_metadata * sm)593 xfs_scrub_metadata(
594 struct file *file,
595 struct xfs_scrub_metadata *sm)
596 {
597 struct xchk_stats_run run = { };
598 struct xfs_scrub *sc;
599 struct xfs_mount *mp = XFS_I(file_inode(file))->i_mount;
600 u64 check_start;
601 int error = 0;
602
603 BUILD_BUG_ON(sizeof(meta_scrub_ops) !=
604 (sizeof(struct xchk_meta_ops) * XFS_SCRUB_TYPE_NR));
605
606 trace_xchk_start(XFS_I(file_inode(file)), sm, error);
607
608 /* Forbidden if we are shut down or mounted norecovery. */
609 error = -ESHUTDOWN;
610 if (xfs_is_shutdown(mp))
611 goto out;
612 error = -ENOTRECOVERABLE;
613 if (xfs_has_norecovery(mp))
614 goto out;
615
616 error = xchk_validate_inputs(mp, sm);
617 if (error)
618 goto out;
619
620 xfs_warn_mount(mp, XFS_OPSTATE_WARNED_SCRUB,
621 "EXPERIMENTAL online scrub feature in use. Use at your own risk!");
622
623 sc = kzalloc(sizeof(struct xfs_scrub), XCHK_GFP_FLAGS);
624 if (!sc) {
625 error = -ENOMEM;
626 goto out;
627 }
628
629 sc->mp = mp;
630 sc->file = file;
631 sc->sm = sm;
632 sc->ops = &meta_scrub_ops[sm->sm_type];
633 sc->sick_mask = xchk_health_mask_for_scrub_type(sm->sm_type);
634 sc->relax = INIT_XCHK_RELAX;
635 retry_op:
636 /*
637 * When repairs are allowed, prevent freezing or readonly remount while
638 * scrub is running with a real transaction.
639 */
640 if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
641 error = mnt_want_write_file(sc->file);
642 if (error)
643 goto out_sc;
644
645 sc->flags |= XCHK_HAVE_FREEZE_PROT;
646 }
647
648 /* Set up for the operation. */
649 error = sc->ops->setup(sc);
650 if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER))
651 goto try_harder;
652 if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN))
653 goto need_drain;
654 if (error)
655 goto out_teardown;
656
657 /* Scrub for errors. */
658 check_start = xchk_stats_now();
659 if ((sc->flags & XREP_ALREADY_FIXED) && sc->ops->repair_eval != NULL)
660 error = sc->ops->repair_eval(sc);
661 else
662 error = sc->ops->scrub(sc);
663 run.scrub_ns += xchk_stats_elapsed_ns(check_start);
664 if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER))
665 goto try_harder;
666 if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN))
667 goto need_drain;
668 if (error || (sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE))
669 goto out_teardown;
670
671 xchk_update_health(sc);
672
673 if (xchk_could_repair(sc)) {
674 /*
675 * If userspace asked for a repair but it wasn't necessary,
676 * report that back to userspace.
677 */
678 if (!xrep_will_attempt(sc)) {
679 sc->sm->sm_flags |= XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED;
680 goto out_nofix;
681 }
682
683 /*
684 * If it's broken, userspace wants us to fix it, and we haven't
685 * already tried to fix it, then attempt a repair.
686 */
687 error = xrep_attempt(sc, &run);
688 if (error == -EAGAIN) {
689 /*
690 * Either the repair function succeeded or it couldn't
691 * get all the resources it needs; either way, we go
692 * back to the beginning and call the scrub function.
693 */
694 error = xchk_teardown(sc, 0);
695 if (error) {
696 xrep_failure(mp);
697 goto out_sc;
698 }
699 goto retry_op;
700 }
701 }
702
703 out_nofix:
704 xchk_postmortem(sc);
705 out_teardown:
706 error = xchk_teardown(sc, error);
707 out_sc:
708 if (error != -ENOENT)
709 xchk_stats_merge(mp, sm, &run);
710 kfree(sc);
711 out:
712 trace_xchk_done(XFS_I(file_inode(file)), sm, error);
713 if (error == -EFSCORRUPTED || error == -EFSBADCRC) {
714 sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
715 error = 0;
716 }
717 return error;
718 need_drain:
719 error = xchk_teardown(sc, 0);
720 if (error)
721 goto out_sc;
722 sc->flags |= XCHK_NEED_DRAIN;
723 run.retries++;
724 goto retry_op;
725 try_harder:
726 /*
727 * Scrubbers return -EDEADLOCK to mean 'try harder'. Tear down
728 * everything we hold, then set up again with preparation for
729 * worst-case scenarios.
730 */
731 error = xchk_teardown(sc, 0);
732 if (error)
733 goto out_sc;
734 sc->flags |= XCHK_TRY_HARDER;
735 run.retries++;
736 goto retry_op;
737 }
738
739 /* Scrub one aspect of one piece of metadata. */
740 int
xfs_ioc_scrub_metadata(struct file * file,void __user * arg)741 xfs_ioc_scrub_metadata(
742 struct file *file,
743 void __user *arg)
744 {
745 struct xfs_scrub_metadata scrub;
746 int error;
747
748 if (!capable(CAP_SYS_ADMIN))
749 return -EPERM;
750
751 if (copy_from_user(&scrub, arg, sizeof(scrub)))
752 return -EFAULT;
753
754 error = xfs_scrub_metadata(file, &scrub);
755 if (error)
756 return error;
757
758 if (copy_to_user(arg, &scrub, sizeof(scrub)))
759 return -EFAULT;
760
761 return 0;
762 }
763
764 /* Decide if there have been any scrub failures up to this point. */
765 static inline int
xfs_scrubv_check_barrier(struct xfs_mount * mp,const struct xfs_scrub_vec * vectors,const struct xfs_scrub_vec * stop_vec)766 xfs_scrubv_check_barrier(
767 struct xfs_mount *mp,
768 const struct xfs_scrub_vec *vectors,
769 const struct xfs_scrub_vec *stop_vec)
770 {
771 const struct xfs_scrub_vec *v;
772 __u32 failmask;
773
774 failmask = stop_vec->sv_flags & XFS_SCRUB_FLAGS_OUT;
775
776 for (v = vectors; v < stop_vec; v++) {
777 if (v->sv_type == XFS_SCRUB_TYPE_BARRIER)
778 continue;
779
780 /*
781 * Runtime errors count as a previous failure, except the ones
782 * used to ask userspace to retry.
783 */
784 switch (v->sv_ret) {
785 case -EBUSY:
786 case -ENOENT:
787 case -EUSERS:
788 case 0:
789 break;
790 default:
791 return -ECANCELED;
792 }
793
794 /*
795 * If any of the out-flags on the scrub vector match the mask
796 * that was set on the barrier vector, that's a previous fail.
797 */
798 if (v->sv_flags & failmask)
799 return -ECANCELED;
800 }
801
802 return 0;
803 }
804
805 /*
806 * If the caller provided us with a nonzero inode number that isn't the ioctl
807 * file, try to grab a reference to it to eliminate all further untrusted inode
808 * lookups. If we can't get the inode, let each scrub function try again.
809 */
810 STATIC struct xfs_inode *
xchk_scrubv_open_by_handle(struct xfs_mount * mp,const struct xfs_scrub_vec_head * head)811 xchk_scrubv_open_by_handle(
812 struct xfs_mount *mp,
813 const struct xfs_scrub_vec_head *head)
814 {
815 struct xfs_trans *tp;
816 struct xfs_inode *ip;
817 int error;
818
819 error = xfs_trans_alloc_empty(mp, &tp);
820 if (error)
821 return NULL;
822
823 error = xfs_iget(mp, tp, head->svh_ino, XCHK_IGET_FLAGS, 0, &ip);
824 xfs_trans_cancel(tp);
825 if (error)
826 return NULL;
827
828 if (VFS_I(ip)->i_generation != head->svh_gen) {
829 xfs_irele(ip);
830 return NULL;
831 }
832
833 return ip;
834 }
835
836 /* Vectored scrub implementation to reduce ioctl calls. */
837 int
xfs_ioc_scrubv_metadata(struct file * file,void __user * arg)838 xfs_ioc_scrubv_metadata(
839 struct file *file,
840 void __user *arg)
841 {
842 struct xfs_scrub_vec_head head;
843 struct xfs_scrub_vec_head __user *uhead = arg;
844 struct xfs_scrub_vec *vectors;
845 struct xfs_scrub_vec __user *uvectors;
846 struct xfs_inode *ip_in = XFS_I(file_inode(file));
847 struct xfs_mount *mp = ip_in->i_mount;
848 struct xfs_inode *handle_ip = NULL;
849 struct xfs_scrub_vec *v;
850 size_t vec_bytes;
851 unsigned int i;
852 int error = 0;
853
854 if (!capable(CAP_SYS_ADMIN))
855 return -EPERM;
856
857 if (copy_from_user(&head, uhead, sizeof(head)))
858 return -EFAULT;
859
860 if (head.svh_reserved)
861 return -EINVAL;
862 if (head.svh_flags & ~XFS_SCRUB_VEC_FLAGS_ALL)
863 return -EINVAL;
864 if (head.svh_nr == 0)
865 return 0;
866
867 vec_bytes = array_size(head.svh_nr, sizeof(struct xfs_scrub_vec));
868 if (vec_bytes > PAGE_SIZE)
869 return -ENOMEM;
870
871 uvectors = u64_to_user_ptr(head.svh_vectors);
872 vectors = memdup_user(uvectors, vec_bytes);
873 if (IS_ERR(vectors))
874 return PTR_ERR(vectors);
875
876 trace_xchk_scrubv_start(ip_in, &head);
877
878 for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
879 if (v->sv_reserved) {
880 error = -EINVAL;
881 goto out_free;
882 }
883
884 if (v->sv_type == XFS_SCRUB_TYPE_BARRIER &&
885 (v->sv_flags & ~XFS_SCRUB_FLAGS_OUT)) {
886 error = -EINVAL;
887 goto out_free;
888 }
889
890 trace_xchk_scrubv_item(mp, &head, i, v);
891 }
892
893 /*
894 * If the caller wants us to do a scrub-by-handle and the file used to
895 * call the ioctl is not the same file, load the incore inode and pin
896 * it across all the scrubv actions to avoid repeated UNTRUSTED
897 * lookups. The reference is not passed to deeper layers of scrub
898 * because each scrubber gets to decide its own strategy and return
899 * values for getting an inode.
900 */
901 if (head.svh_ino && head.svh_ino != ip_in->i_ino)
902 handle_ip = xchk_scrubv_open_by_handle(mp, &head);
903
904 /* Run all the scrubbers. */
905 for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
906 struct xfs_scrub_metadata sm = {
907 .sm_type = v->sv_type,
908 .sm_flags = v->sv_flags,
909 .sm_ino = head.svh_ino,
910 .sm_gen = head.svh_gen,
911 .sm_agno = head.svh_agno,
912 };
913
914 if (v->sv_type == XFS_SCRUB_TYPE_BARRIER) {
915 v->sv_ret = xfs_scrubv_check_barrier(mp, vectors, v);
916 if (v->sv_ret) {
917 trace_xchk_scrubv_barrier_fail(mp, &head, i, v);
918 break;
919 }
920
921 continue;
922 }
923
924 v->sv_ret = xfs_scrub_metadata(file, &sm);
925 v->sv_flags = sm.sm_flags;
926
927 trace_xchk_scrubv_outcome(mp, &head, i, v);
928
929 if (head.svh_rest_us) {
930 ktime_t expires;
931
932 expires = ktime_add_ns(ktime_get(),
933 head.svh_rest_us * 1000);
934 set_current_state(TASK_KILLABLE);
935 schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
936 }
937
938 if (fatal_signal_pending(current)) {
939 error = -EINTR;
940 goto out_free;
941 }
942 }
943
944 if (copy_to_user(uvectors, vectors, vec_bytes) ||
945 copy_to_user(uhead, &head, sizeof(head))) {
946 error = -EFAULT;
947 goto out_free;
948 }
949
950 out_free:
951 if (handle_ip)
952 xfs_irele(handle_ip);
953 kfree(vectors);
954 return error;
955 }
956