1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * io.c
4 *
5 * Buffer cache handling
6 *
7 * Copyright (C) 2002, 2004 Oracle. All rights reserved.
8 */
9
10 #include <linux/fs.h>
11 #include <linux/types.h>
12 #include <linux/highmem.h>
13 #include <linux/bio.h>
14
15 #include <cluster/masklog.h>
16
17 #include "ocfs2.h"
18
19 #include "alloc.h"
20 #include "inode.h"
21 #include "journal.h"
22 #include "uptodate.h"
23 #include "buffer_head_io.h"
24 #include "ocfs2_trace.h"
25
26 /*
27 * Bits on bh->b_state used by ocfs2.
28 *
29 * These MUST be after the JBD2 bits. Hence, we use BH_JBDPrivateStart.
30 */
31 enum ocfs2_state_bits {
32 BH_NeedsValidate = BH_JBDPrivateStart,
33 };
34
35 /* Expand the magic b_state functions */
36 BUFFER_FNS(NeedsValidate, needs_validate);
37
38 int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
39 struct ocfs2_caching_info *ci)
40 {
41 int ret = 0;
42
43 trace_ocfs2_write_block((unsigned long long)bh->b_blocknr, ci);
44
45 BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO);
46 BUG_ON(buffer_jbd(bh));
47
48 /* No need to check for a soft readonly file system here. non
49 * journalled writes are only ever done on system files which
50 * can get modified during recovery even if read-only. */
51 if (ocfs2_is_hard_readonly(osb)) {
52 ret = -EROFS;
53 mlog_errno(ret);
54 goto out;
55 }
56
57 ocfs2_metadata_cache_io_lock(ci);
58
59 lock_buffer(bh);
60 set_buffer_uptodate(bh);
61
62 /* remove from dirty list before I/O. */
63 clear_buffer_dirty(bh);
64
65 get_bh(bh); /* for end_buffer_write_sync() */
66 bh->b_end_io = end_buffer_write_sync;
67 submit_bh(REQ_OP_WRITE, bh);
68
69 wait_on_buffer(bh);
70
71 if (buffer_uptodate(bh)) {
72 ocfs2_set_buffer_uptodate(ci, bh);
73 } else {
74 /* We don't need to remove the clustered uptodate
75 * information for this bh as it's not marked locally
76 * uptodate. */
77 ret = -EIO;
78 mlog_errno(ret);
79 }
80
81 ocfs2_metadata_cache_io_unlock(ci);
82 out:
83 return ret;
84 }
85
86 /* Caller must provide a bhs[] with all NULL or non-NULL entries, so it
87 * will be easier to handle read failure.
88 */
89 int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block,
90 unsigned int nr, struct buffer_head *bhs[])
91 {
92 int status = 0;
93 unsigned int i;
94 struct buffer_head *bh;
95 int new_bh = 0;
96
97 trace_ocfs2_read_blocks_sync((unsigned long long)block, nr);
98
99 if (!nr)
100 goto bail;
101
102 /* Don't put buffer head and re-assign it to NULL if it is allocated
103 * outside since the caller can't be aware of this alternation!
104 */
105 new_bh = (bhs[0] == NULL);
106
107 for (i = 0 ; i < nr ; i++) {
108 if (bhs[i] == NULL) {
109 bhs[i] = sb_getblk(osb->sb, block++);
110 if (bhs[i] == NULL) {
111 status = -ENOMEM;
112 mlog_errno(status);
113 break;
114 }
115 }
116 bh = bhs[i];
117
118 if (buffer_jbd(bh)) {
119 trace_ocfs2_read_blocks_sync_jbd(
120 (unsigned long long)bh->b_blocknr);
121 continue;
122 }
123
124 if (buffer_dirty(bh)) {
125 /* This should probably be a BUG, or
126 * at least return an error. */
127 mlog(ML_ERROR,
128 "trying to sync read a dirty "
129 "buffer! (blocknr = %llu), skipping\n",
130 (unsigned long long)bh->b_blocknr);
131 continue;
132 }
133
134 lock_buffer(bh);
135 if (buffer_jbd(bh)) {
136 #ifdef CATCH_BH_JBD_RACES
137 mlog(ML_ERROR,
138 "block %llu had the JBD bit set "
139 "while I was in lock_buffer!",
140 (unsigned long long)bh->b_blocknr);
141 BUG();
142 #else
143 unlock_buffer(bh);
144 continue;
145 #endif
146 }
147
148 get_bh(bh); /* for end_buffer_read_sync() */
149 bh->b_end_io = end_buffer_read_sync;
150 submit_bh(REQ_OP_READ, bh);
151 }
152
153 read_failure:
154 for (i = nr; i > 0; i--) {
155 bh = bhs[i - 1];
156
157 if (unlikely(status)) {
158 if (new_bh && bh) {
159 /* If middle bh fails, let previous bh
160 * finish its read and then put it to
161 * avoid bh leak
162 */
163 if (!buffer_jbd(bh))
164 wait_on_buffer(bh);
165 put_bh(bh);
166 bhs[i - 1] = NULL;
167 } else if (bh && buffer_uptodate(bh)) {
168 clear_buffer_uptodate(bh);
169 }
170 continue;
171 }
172
173 /* No need to wait on the buffer if it's managed by JBD. */
174 if (!buffer_jbd(bh))
175 wait_on_buffer(bh);
176
177 if (!buffer_uptodate(bh)) {
178 /* Status won't be cleared from here on out,
179 * so we can safely record this and loop back
180 * to cleanup the other buffers. */
181 status = -EIO;
182 goto read_failure;
183 }
184 }
185
186 bail:
187 return status;
188 }
189
190 /* Caller must provide a bhs[] with all NULL or non-NULL entries, so it
191 * will be easier to handle read failure.
192 */
193 int ocfs2_read_blocks(struct ocfs2_caching_info *ci, u64 block, int nr,
194 struct buffer_head *bhs[], int flags,
195 int (*validate)(struct super_block *sb,
196 struct buffer_head *bh))
197 {
198 int status = 0;
199 int i, ignore_cache = 0;
200 struct buffer_head *bh;
201 struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
202 int new_bh = 0;
203
204 trace_ocfs2_read_blocks_begin(ci, (unsigned long long)block, nr, flags);
205
206 BUG_ON(!ci);
207 BUG_ON((flags & OCFS2_BH_READAHEAD) &&
208 (flags & OCFS2_BH_IGNORE_CACHE));
209
210 if (bhs == NULL) {
211 status = -EINVAL;
212 mlog_errno(status);
213 goto bail;
214 }
215
216 if (nr < 0) {
217 mlog(ML_ERROR, "asked to read %d blocks!\n", nr);
218 status = -EINVAL;
219 mlog_errno(status);
220 goto bail;
221 }
222
223 if (nr == 0) {
224 status = 0;
225 goto bail;
226 }
227
228 /* Don't put buffer head and re-assign it to NULL if it is allocated
229 * outside since the caller can't be aware of this alternation!
230 */
231 new_bh = (bhs[0] == NULL);
232
233 ocfs2_metadata_cache_io_lock(ci);
234 for (i = 0 ; i < nr ; i++) {
235 if (bhs[i] == NULL) {
236 bhs[i] = sb_getblk(sb, block++);
237 if (bhs[i] == NULL) {
238 status = -ENOMEM;
239 mlog_errno(status);
240 /* Don't forget to put previous bh! */
241 break;
242 }
243 }
244 bh = bhs[i];
245 ignore_cache = (flags & OCFS2_BH_IGNORE_CACHE);
246
247 /* There are three read-ahead cases here which we need to
248 * be concerned with. All three assume a buffer has
249 * previously been submitted with OCFS2_BH_READAHEAD
250 * and it hasn't yet completed I/O.
251 *
252 * 1) The current request is sync to disk. This rarely
253 * happens these days, and never when performance
254 * matters - the code can just wait on the buffer
255 * lock and re-submit.
256 *
257 * 2) The current request is cached, but not
258 * readahead. ocfs2_buffer_uptodate() will return
259 * false anyway, so we'll wind up waiting on the
260 * buffer lock to do I/O. We re-check the request
261 * with after getting the lock to avoid a re-submit.
262 *
263 * 3) The current request is readahead (and so must
264 * also be a caching one). We short circuit if the
265 * buffer is locked (under I/O) and if it's in the
266 * uptodate cache. The re-check from #2 catches the
267 * case that the previous read-ahead completes just
268 * before our is-it-in-flight check.
269 */
270
271 if (!ignore_cache && !ocfs2_buffer_uptodate(ci, bh)) {
272 trace_ocfs2_read_blocks_from_disk(
273 (unsigned long long)bh->b_blocknr,
274 (unsigned long long)ocfs2_metadata_cache_owner(ci));
275 /* We're using ignore_cache here to say
276 * "go to disk" */
277 ignore_cache = 1;
278 }
279
280 trace_ocfs2_read_blocks_bh((unsigned long long)bh->b_blocknr,
281 ignore_cache, buffer_jbd(bh), buffer_dirty(bh));
282
283 if (buffer_jbd(bh)) {
284 continue;
285 }
286
287 if (ignore_cache) {
288 if (buffer_dirty(bh)) {
289 /* This should probably be a BUG, or
290 * at least return an error. */
291 continue;
292 }
293
294 /* A read-ahead request was made - if the
295 * buffer is already under read-ahead from a
296 * previously submitted request than we are
297 * done here. */
298 if ((flags & OCFS2_BH_READAHEAD)
299 && ocfs2_buffer_read_ahead(ci, bh))
300 continue;
301
302 lock_buffer(bh);
303 if (buffer_jbd(bh)) {
304 #ifdef CATCH_BH_JBD_RACES
305 mlog(ML_ERROR, "block %llu had the JBD bit set "
306 "while I was in lock_buffer!",
307 (unsigned long long)bh->b_blocknr);
308 BUG();
309 #else
310 unlock_buffer(bh);
311 continue;
312 #endif
313 }
314
315 /* Re-check ocfs2_buffer_uptodate() as a
316 * previously read-ahead buffer may have
317 * completed I/O while we were waiting for the
318 * buffer lock. */
319 if (!(flags & OCFS2_BH_IGNORE_CACHE)
320 && !(flags & OCFS2_BH_READAHEAD)
321 && ocfs2_buffer_uptodate(ci, bh)) {
322 unlock_buffer(bh);
323 continue;
324 }
325
326 get_bh(bh); /* for end_buffer_read_sync() */
327 if (validate)
328 set_buffer_needs_validate(bh);
329 bh->b_end_io = end_buffer_read_sync;
330 submit_bh(REQ_OP_READ, bh);
331 continue;
332 }
333 }
334
335 read_failure:
336 for (i = (nr - 1); i >= 0; i--) {
337 bh = bhs[i];
338
339 if (!(flags & OCFS2_BH_READAHEAD)) {
340 if (unlikely(status)) {
341 /* Clear the buffers on error including those
342 * ever succeeded in reading
343 */
344 if (new_bh && bh) {
345 /* If middle bh fails, let previous bh
346 * finish its read and then put it to
347 * avoid bh leak
348 */
349 if (!buffer_jbd(bh))
350 wait_on_buffer(bh);
351 put_bh(bh);
352 bhs[i] = NULL;
353 } else if (bh && buffer_uptodate(bh)) {
354 clear_buffer_uptodate(bh);
355 }
356 continue;
357 }
358 /* We know this can't have changed as we hold the
359 * owner sem. Avoid doing any work on the bh if the
360 * journal has it. */
361 if (!buffer_jbd(bh))
362 wait_on_buffer(bh);
363
364 if (!buffer_uptodate(bh)) {
365 /* Status won't be cleared from here on out,
366 * so we can safely record this and loop back
367 * to cleanup the other buffers. Don't need to
368 * remove the clustered uptodate information
369 * for this bh as it's not marked locally
370 * uptodate. */
371 status = -EIO;
372 clear_buffer_needs_validate(bh);
373 goto read_failure;
374 }
375
376 if (buffer_needs_validate(bh)) {
377 /* We never set NeedsValidate if the
378 * buffer was held by the journal, so
379 * that better not have changed */
380 BUG_ON(buffer_jbd(bh));
381 clear_buffer_needs_validate(bh);
382 status = validate(sb, bh);
383 if (status)
384 goto read_failure;
385 }
386 }
387
388 /* Always set the buffer in the cache, even if it was
389 * a forced read, or read-ahead which hasn't yet
390 * completed. */
391 if (bh)
392 ocfs2_set_buffer_uptodate(ci, bh);
393 }
394 ocfs2_metadata_cache_io_unlock(ci);
395
396 trace_ocfs2_read_blocks_end((unsigned long long)block, nr,
397 flags, ignore_cache);
398
399 bail:
400
401 return status;
402 }
403
404 /* Check whether the blkno is the super block or one of the backups. */
405 static void ocfs2_check_super_or_backup(struct super_block *sb,
406 sector_t blkno)
407 {
408 int i;
409 u64 backup_blkno;
410
411 if (blkno == OCFS2_SUPER_BLOCK_BLKNO)
412 return;
413
414 for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
415 backup_blkno = ocfs2_backup_super_blkno(sb, i);
416 if (backup_blkno == blkno)
417 return;
418 }
419
420 BUG();
421 }
422
423 /*
424 * Write super block and backups doesn't need to collaborate with journal,
425 * so we don't need to lock ip_io_mutex and ci doesn't need to bea passed
426 * into this function.
427 */
428 int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
429 struct buffer_head *bh)
430 {
431 int ret = 0;
432 struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;
433
434 BUG_ON(buffer_jbd(bh));
435 ocfs2_check_super_or_backup(osb->sb, bh->b_blocknr);
436
437 if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) {
438 ret = -EROFS;
439 mlog_errno(ret);
440 goto out;
441 }
442
443 lock_buffer(bh);
444 set_buffer_uptodate(bh);
445
446 /* remove from dirty list before I/O. */
447 clear_buffer_dirty(bh);
448
449 get_bh(bh); /* for end_buffer_write_sync() */
450 bh->b_end_io = end_buffer_write_sync;
451 ocfs2_compute_meta_ecc(osb->sb, bh->b_data, &di->i_check);
452 submit_bh(REQ_OP_WRITE, bh);
453
454 wait_on_buffer(bh);
455
456 if (!buffer_uptodate(bh)) {
457 ret = -EIO;
458 mlog_errno(ret);
459 }
460
461 out:
462 return ret;
463 }
464
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