ARM: tegra11: clock: Update EMC clock mux
[linux-2.6.git] / fs / ocfs2 / buffer_head_io.c
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * io.c
5  *
6  * Buffer cache handling
7  *
8  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public
12  * License as published by the Free Software Foundation; either
13  * version 2 of the License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public
21  * License along with this program; if not, write to the
22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23  * Boston, MA 021110-1307, USA.
24  */
25
26 #include <linux/fs.h>
27 #include <linux/types.h>
28 #include <linux/highmem.h>
29
30 #include <cluster/masklog.h>
31
32 #include "ocfs2.h"
33
34 #include "alloc.h"
35 #include "inode.h"
36 #include "journal.h"
37 #include "uptodate.h"
38 #include "buffer_head_io.h"
39 #include "ocfs2_trace.h"
40
41 /*
42  * Bits on bh->b_state used by ocfs2.
43  *
44  * These MUST be after the JBD2 bits.  Hence, we use BH_JBDPrivateStart.
45  */
46 enum ocfs2_state_bits {
47         BH_NeedsValidate = BH_JBDPrivateStart,
48 };
49
50 /* Expand the magic b_state functions */
51 BUFFER_FNS(NeedsValidate, needs_validate);
52
53 int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
54                       struct ocfs2_caching_info *ci)
55 {
56         int ret = 0;
57
58         trace_ocfs2_write_block((unsigned long long)bh->b_blocknr, ci);
59
60         BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO);
61         BUG_ON(buffer_jbd(bh));
62
63         /* No need to check for a soft readonly file system here. non
64          * journalled writes are only ever done on system files which
65          * can get modified during recovery even if read-only. */
66         if (ocfs2_is_hard_readonly(osb)) {
67                 ret = -EROFS;
68                 mlog_errno(ret);
69                 goto out;
70         }
71
72         ocfs2_metadata_cache_io_lock(ci);
73
74         lock_buffer(bh);
75         set_buffer_uptodate(bh);
76
77         /* remove from dirty list before I/O. */
78         clear_buffer_dirty(bh);
79
80         get_bh(bh); /* for end_buffer_write_sync() */
81         bh->b_end_io = end_buffer_write_sync;
82         submit_bh(WRITE, bh);
83
84         wait_on_buffer(bh);
85
86         if (buffer_uptodate(bh)) {
87                 ocfs2_set_buffer_uptodate(ci, bh);
88         } else {
89                 /* We don't need to remove the clustered uptodate
90                  * information for this bh as it's not marked locally
91                  * uptodate. */
92                 ret = -EIO;
93                 put_bh(bh);
94                 mlog_errno(ret);
95         }
96
97         ocfs2_metadata_cache_io_unlock(ci);
98 out:
99         return ret;
100 }
101
102 int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block,
103                            unsigned int nr, struct buffer_head *bhs[])
104 {
105         int status = 0;
106         unsigned int i;
107         struct buffer_head *bh;
108
109         trace_ocfs2_read_blocks_sync((unsigned long long)block, nr);
110
111         if (!nr)
112                 goto bail;
113
114         for (i = 0 ; i < nr ; i++) {
115                 if (bhs[i] == NULL) {
116                         bhs[i] = sb_getblk(osb->sb, block++);
117                         if (bhs[i] == NULL) {
118                                 status = -EIO;
119                                 mlog_errno(status);
120                                 goto bail;
121                         }
122                 }
123                 bh = bhs[i];
124
125                 if (buffer_jbd(bh)) {
126                         trace_ocfs2_read_blocks_sync_jbd(
127                                         (unsigned long long)bh->b_blocknr);
128                         continue;
129                 }
130
131                 if (buffer_dirty(bh)) {
132                         /* This should probably be a BUG, or
133                          * at least return an error. */
134                         mlog(ML_ERROR,
135                              "trying to sync read a dirty "
136                              "buffer! (blocknr = %llu), skipping\n",
137                              (unsigned long long)bh->b_blocknr);
138                         continue;
139                 }
140
141                 lock_buffer(bh);
142                 if (buffer_jbd(bh)) {
143                         mlog(ML_ERROR,
144                              "block %llu had the JBD bit set "
145                              "while I was in lock_buffer!",
146                              (unsigned long long)bh->b_blocknr);
147                         BUG();
148                 }
149
150                 clear_buffer_uptodate(bh);
151                 get_bh(bh); /* for end_buffer_read_sync() */
152                 bh->b_end_io = end_buffer_read_sync;
153                 submit_bh(READ, bh);
154         }
155
156         for (i = nr; i > 0; i--) {
157                 bh = bhs[i - 1];
158
159                 /* No need to wait on the buffer if it's managed by JBD. */
160                 if (!buffer_jbd(bh))
161                         wait_on_buffer(bh);
162
163                 if (!buffer_uptodate(bh)) {
164                         /* Status won't be cleared from here on out,
165                          * so we can safely record this and loop back
166                          * to cleanup the other buffers. */
167                         status = -EIO;
168                         put_bh(bh);
169                         bhs[i - 1] = NULL;
170                 }
171         }
172
173 bail:
174         return status;
175 }
176
177 int ocfs2_read_blocks(struct ocfs2_caching_info *ci, u64 block, int nr,
178                       struct buffer_head *bhs[], int flags,
179                       int (*validate)(struct super_block *sb,
180                                       struct buffer_head *bh))
181 {
182         int status = 0;
183         int i, ignore_cache = 0;
184         struct buffer_head *bh;
185         struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
186
187         trace_ocfs2_read_blocks_begin(ci, (unsigned long long)block, nr, flags);
188
189         BUG_ON(!ci);
190         BUG_ON((flags & OCFS2_BH_READAHEAD) &&
191                (flags & OCFS2_BH_IGNORE_CACHE));
192
193         if (bhs == NULL) {
194                 status = -EINVAL;
195                 mlog_errno(status);
196                 goto bail;
197         }
198
199         if (nr < 0) {
200                 mlog(ML_ERROR, "asked to read %d blocks!\n", nr);
201                 status = -EINVAL;
202                 mlog_errno(status);
203                 goto bail;
204         }
205
206         if (nr == 0) {
207                 status = 0;
208                 goto bail;
209         }
210
211         ocfs2_metadata_cache_io_lock(ci);
212         for (i = 0 ; i < nr ; i++) {
213                 if (bhs[i] == NULL) {
214                         bhs[i] = sb_getblk(sb, block++);
215                         if (bhs[i] == NULL) {
216                                 ocfs2_metadata_cache_io_unlock(ci);
217                                 status = -EIO;
218                                 mlog_errno(status);
219                                 goto bail;
220                         }
221                 }
222                 bh = bhs[i];
223                 ignore_cache = (flags & OCFS2_BH_IGNORE_CACHE);
224
225                 /* There are three read-ahead cases here which we need to
226                  * be concerned with. All three assume a buffer has
227                  * previously been submitted with OCFS2_BH_READAHEAD
228                  * and it hasn't yet completed I/O.
229                  *
230                  * 1) The current request is sync to disk. This rarely
231                  *    happens these days, and never when performance
232                  *    matters - the code can just wait on the buffer
233                  *    lock and re-submit.
234                  *
235                  * 2) The current request is cached, but not
236                  *    readahead. ocfs2_buffer_uptodate() will return
237                  *    false anyway, so we'll wind up waiting on the
238                  *    buffer lock to do I/O. We re-check the request
239                  *    with after getting the lock to avoid a re-submit.
240                  *
241                  * 3) The current request is readahead (and so must
242                  *    also be a caching one). We short circuit if the
243                  *    buffer is locked (under I/O) and if it's in the
244                  *    uptodate cache. The re-check from #2 catches the
245                  *    case that the previous read-ahead completes just
246                  *    before our is-it-in-flight check.
247                  */
248
249                 if (!ignore_cache && !ocfs2_buffer_uptodate(ci, bh)) {
250                         trace_ocfs2_read_blocks_from_disk(
251                              (unsigned long long)bh->b_blocknr,
252                              (unsigned long long)ocfs2_metadata_cache_owner(ci));
253                         /* We're using ignore_cache here to say
254                          * "go to disk" */
255                         ignore_cache = 1;
256                 }
257
258                 trace_ocfs2_read_blocks_bh((unsigned long long)bh->b_blocknr,
259                         ignore_cache, buffer_jbd(bh), buffer_dirty(bh));
260
261                 if (buffer_jbd(bh)) {
262                         continue;
263                 }
264
265                 if (ignore_cache) {
266                         if (buffer_dirty(bh)) {
267                                 /* This should probably be a BUG, or
268                                  * at least return an error. */
269                                 continue;
270                         }
271
272                         /* A read-ahead request was made - if the
273                          * buffer is already under read-ahead from a
274                          * previously submitted request than we are
275                          * done here. */
276                         if ((flags & OCFS2_BH_READAHEAD)
277                             && ocfs2_buffer_read_ahead(ci, bh))
278                                 continue;
279
280                         lock_buffer(bh);
281                         if (buffer_jbd(bh)) {
282 #ifdef CATCH_BH_JBD_RACES
283                                 mlog(ML_ERROR, "block %llu had the JBD bit set "
284                                                "while I was in lock_buffer!",
285                                      (unsigned long long)bh->b_blocknr);
286                                 BUG();
287 #else
288                                 unlock_buffer(bh);
289                                 continue;
290 #endif
291                         }
292
293                         /* Re-check ocfs2_buffer_uptodate() as a
294                          * previously read-ahead buffer may have
295                          * completed I/O while we were waiting for the
296                          * buffer lock. */
297                         if (!(flags & OCFS2_BH_IGNORE_CACHE)
298                             && !(flags & OCFS2_BH_READAHEAD)
299                             && ocfs2_buffer_uptodate(ci, bh)) {
300                                 unlock_buffer(bh);
301                                 continue;
302                         }
303
304                         clear_buffer_uptodate(bh);
305                         get_bh(bh); /* for end_buffer_read_sync() */
306                         if (validate)
307                                 set_buffer_needs_validate(bh);
308                         bh->b_end_io = end_buffer_read_sync;
309                         submit_bh(READ, bh);
310                         continue;
311                 }
312         }
313
314         status = 0;
315
316         for (i = (nr - 1); i >= 0; i--) {
317                 bh = bhs[i];
318
319                 if (!(flags & OCFS2_BH_READAHEAD)) {
320                         /* We know this can't have changed as we hold the
321                          * owner sem. Avoid doing any work on the bh if the
322                          * journal has it. */
323                         if (!buffer_jbd(bh))
324                                 wait_on_buffer(bh);
325
326                         if (!buffer_uptodate(bh)) {
327                                 /* Status won't be cleared from here on out,
328                                  * so we can safely record this and loop back
329                                  * to cleanup the other buffers. Don't need to
330                                  * remove the clustered uptodate information
331                                  * for this bh as it's not marked locally
332                                  * uptodate. */
333                                 status = -EIO;
334                                 put_bh(bh);
335                                 bhs[i] = NULL;
336                                 continue;
337                         }
338
339                         if (buffer_needs_validate(bh)) {
340                                 /* We never set NeedsValidate if the
341                                  * buffer was held by the journal, so
342                                  * that better not have changed */
343                                 BUG_ON(buffer_jbd(bh));
344                                 clear_buffer_needs_validate(bh);
345                                 status = validate(sb, bh);
346                                 if (status) {
347                                         put_bh(bh);
348                                         bhs[i] = NULL;
349                                         continue;
350                                 }
351                         }
352                 }
353
354                 /* Always set the buffer in the cache, even if it was
355                  * a forced read, or read-ahead which hasn't yet
356                  * completed. */
357                 ocfs2_set_buffer_uptodate(ci, bh);
358         }
359         ocfs2_metadata_cache_io_unlock(ci);
360
361         trace_ocfs2_read_blocks_end((unsigned long long)block, nr,
362                                     flags, ignore_cache);
363
364 bail:
365
366         return status;
367 }
368
369 /* Check whether the blkno is the super block or one of the backups. */
370 static void ocfs2_check_super_or_backup(struct super_block *sb,
371                                         sector_t blkno)
372 {
373         int i;
374         u64 backup_blkno;
375
376         if (blkno == OCFS2_SUPER_BLOCK_BLKNO)
377                 return;
378
379         for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) {
380                 backup_blkno = ocfs2_backup_super_blkno(sb, i);
381                 if (backup_blkno == blkno)
382                         return;
383         }
384
385         BUG();
386 }
387
388 /*
389  * Write super block and backups doesn't need to collaborate with journal,
390  * so we don't need to lock ip_io_mutex and ci doesn't need to bea passed
391  * into this function.
392  */
393 int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
394                                 struct buffer_head *bh)
395 {
396         int ret = 0;
397         struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;
398
399         BUG_ON(buffer_jbd(bh));
400         ocfs2_check_super_or_backup(osb->sb, bh->b_blocknr);
401
402         if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) {
403                 ret = -EROFS;
404                 mlog_errno(ret);
405                 goto out;
406         }
407
408         lock_buffer(bh);
409         set_buffer_uptodate(bh);
410
411         /* remove from dirty list before I/O. */
412         clear_buffer_dirty(bh);
413
414         get_bh(bh); /* for end_buffer_write_sync() */
415         bh->b_end_io = end_buffer_write_sync;
416         ocfs2_compute_meta_ecc(osb->sb, bh->b_data, &di->i_check);
417         submit_bh(WRITE, bh);
418
419         wait_on_buffer(bh);
420
421         if (!buffer_uptodate(bh)) {
422                 ret = -EIO;
423                 put_bh(bh);
424                 mlog_errno(ret);
425         }
426
427 out:
428         return ret;
429 }