d_path: Make d_path() use a struct path
[linux-2.6.git] / drivers / md / bitmap.c
1 /*
2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
3  *
4  * bitmap_create  - sets up the bitmap structure
5  * bitmap_destroy - destroys the bitmap structure
6  *
7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
8  * - added disk storage for bitmap
9  * - changes to allow various bitmap chunk sizes
10  */
11
12 /*
13  * Still to do:
14  *
15  * flush after percent set rather than just time based. (maybe both).
16  * wait if count gets too high, wake when it drops to half.
17  */
18
19 #include <linux/module.h>
20 #include <linux/errno.h>
21 #include <linux/slab.h>
22 #include <linux/init.h>
23 #include <linux/timer.h>
24 #include <linux/sched.h>
25 #include <linux/list.h>
26 #include <linux/file.h>
27 #include <linux/mount.h>
28 #include <linux/buffer_head.h>
29 #include <linux/raid/md.h>
30 #include <linux/raid/bitmap.h>
31
32 /* debug macros */
33
34 #define DEBUG 0
35
36 #if DEBUG
37 /* these are for debugging purposes only! */
38
39 /* define one and only one of these */
40 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
41 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
42 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
43 #define INJECT_FAULTS_4 0 /* undef */
44 #define INJECT_FAULTS_5 0 /* undef */
45 #define INJECT_FAULTS_6 0
46
47 /* if these are defined, the driver will fail! debug only */
48 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
49 #define INJECT_FATAL_FAULT_2 0 /* undef */
50 #define INJECT_FATAL_FAULT_3 0 /* undef */
51 #endif
52
53 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
54 #define DPRINTK(x...) do { } while(0)
55
56 #ifndef PRINTK
57 #  if DEBUG > 0
58 #    define PRINTK(x...) printk(KERN_DEBUG x)
59 #  else
60 #    define PRINTK(x...)
61 #  endif
62 #endif
63
64 static inline char * bmname(struct bitmap *bitmap)
65 {
66         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
67 }
68
69
70 /*
71  * just a placeholder - calls kmalloc for bitmap pages
72  */
73 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
74 {
75         unsigned char *page;
76
77 #ifdef INJECT_FAULTS_1
78         page = NULL;
79 #else
80         page = kmalloc(PAGE_SIZE, GFP_NOIO);
81 #endif
82         if (!page)
83                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
84         else
85                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
86                         bmname(bitmap), page);
87         return page;
88 }
89
90 /*
91  * for now just a placeholder -- just calls kfree for bitmap pages
92  */
93 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
94 {
95         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
96         kfree(page);
97 }
98
99 /*
100  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
101  *
102  * 1) check to see if this page is allocated, if it's not then try to alloc
103  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
104  *    page pointer directly as a counter
105  *
106  * if we find our page, we increment the page's refcount so that it stays
107  * allocated while we're using it
108  */
109 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
110 {
111         unsigned char *mappage;
112
113         if (page >= bitmap->pages) {
114                 printk(KERN_ALERT
115                         "%s: invalid bitmap page request: %lu (> %lu)\n",
116                         bmname(bitmap), page, bitmap->pages-1);
117                 return -EINVAL;
118         }
119
120
121         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
122                 return 0;
123
124         if (bitmap->bp[page].map) /* page is already allocated, just return */
125                 return 0;
126
127         if (!create)
128                 return -ENOENT;
129
130         spin_unlock_irq(&bitmap->lock);
131
132         /* this page has not been allocated yet */
133
134         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
135                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
136                         bmname(bitmap));
137                 /* failed - set the hijacked flag so that we can use the
138                  * pointer as a counter */
139                 spin_lock_irq(&bitmap->lock);
140                 if (!bitmap->bp[page].map)
141                         bitmap->bp[page].hijacked = 1;
142                 goto out;
143         }
144
145         /* got a page */
146
147         spin_lock_irq(&bitmap->lock);
148
149         /* recheck the page */
150
151         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
152                 /* somebody beat us to getting the page */
153                 bitmap_free_page(bitmap, mappage);
154                 return 0;
155         }
156
157         /* no page was in place and we have one, so install it */
158
159         memset(mappage, 0, PAGE_SIZE);
160         bitmap->bp[page].map = mappage;
161         bitmap->missing_pages--;
162 out:
163         return 0;
164 }
165
166
167 /* if page is completely empty, put it back on the free list, or dealloc it */
168 /* if page was hijacked, unmark the flag so it might get alloced next time */
169 /* Note: lock should be held when calling this */
170 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
171 {
172         char *ptr;
173
174         if (bitmap->bp[page].count) /* page is still busy */
175                 return;
176
177         /* page is no longer in use, it can be released */
178
179         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
180                 bitmap->bp[page].hijacked = 0;
181                 bitmap->bp[page].map = NULL;
182                 return;
183         }
184
185         /* normal case, free the page */
186
187 #if 0
188 /* actually ... let's not.  We will probably need the page again exactly when
189  * memory is tight and we are flusing to disk
190  */
191         return;
192 #else
193         ptr = bitmap->bp[page].map;
194         bitmap->bp[page].map = NULL;
195         bitmap->missing_pages++;
196         bitmap_free_page(bitmap, ptr);
197         return;
198 #endif
199 }
200
201
202 /*
203  * bitmap file handling - read and write the bitmap file and its superblock
204  */
205
206 /* copy the pathname of a file to a buffer */
207 char *file_path(struct file *file, char *buf, int count)
208 {
209         if (!buf)
210                 return NULL;
211
212         buf = d_path(&file->f_path, buf, count);
213
214         return IS_ERR(buf) ? NULL : buf;
215 }
216
217 /*
218  * basic page I/O operations
219  */
220
221 /* IO operations when bitmap is stored near all superblocks */
222 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
223 {
224         /* choose a good rdev and read the page from there */
225
226         mdk_rdev_t *rdev;
227         struct list_head *tmp;
228         struct page *page = alloc_page(GFP_KERNEL);
229         sector_t target;
230
231         if (!page)
232                 return ERR_PTR(-ENOMEM);
233
234         rdev_for_each(rdev, tmp, mddev) {
235                 if (! test_bit(In_sync, &rdev->flags)
236                     || test_bit(Faulty, &rdev->flags))
237                         continue;
238
239                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
240
241                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
242                         page->index = index;
243                         attach_page_buffers(page, NULL); /* so that free_buffer will
244                                                           * quietly no-op */
245                         return page;
246                 }
247         }
248         return ERR_PTR(-EIO);
249
250 }
251
252 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
253 {
254         mdk_rdev_t *rdev;
255         struct list_head *tmp;
256         mddev_t *mddev = bitmap->mddev;
257
258         rdev_for_each(rdev, tmp, mddev)
259                 if (test_bit(In_sync, &rdev->flags)
260                     && !test_bit(Faulty, &rdev->flags)) {
261                         int size = PAGE_SIZE;
262                         if (page->index == bitmap->file_pages-1)
263                                 size = roundup(bitmap->last_page_size,
264                                                bdev_hardsect_size(rdev->bdev));
265                         /* Just make sure we aren't corrupting data or
266                          * metadata
267                          */
268                         if (bitmap->offset < 0) {
269                                 /* DATA  BITMAP METADATA  */
270                                 if (bitmap->offset
271                                     + (long)(page->index * (PAGE_SIZE/512))
272                                     + size/512 > 0)
273                                         /* bitmap runs in to metadata */
274                                         return -EINVAL;
275                                 if (rdev->data_offset + mddev->size*2
276                                     > rdev->sb_offset*2 + bitmap->offset)
277                                         /* data runs in to bitmap */
278                                         return -EINVAL;
279                         } else if (rdev->sb_offset*2 < rdev->data_offset) {
280                                 /* METADATA BITMAP DATA */
281                                 if (rdev->sb_offset*2
282                                     + bitmap->offset
283                                     + page->index*(PAGE_SIZE/512) + size/512
284                                     > rdev->data_offset)
285                                         /* bitmap runs in to data */
286                                         return -EINVAL;
287                         } else {
288                                 /* DATA METADATA BITMAP - no problems */
289                         }
290                         md_super_write(mddev, rdev,
291                                        (rdev->sb_offset<<1) + bitmap->offset
292                                        + page->index * (PAGE_SIZE/512),
293                                        size,
294                                        page);
295                 }
296
297         if (wait)
298                 md_super_wait(mddev);
299         return 0;
300 }
301
302 static void bitmap_file_kick(struct bitmap *bitmap);
303 /*
304  * write out a page to a file
305  */
306 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
307 {
308         struct buffer_head *bh;
309
310         if (bitmap->file == NULL) {
311                 switch (write_sb_page(bitmap, page, wait)) {
312                 case -EINVAL:
313                         bitmap->flags |= BITMAP_WRITE_ERROR;
314                 }
315         } else {
316
317                 bh = page_buffers(page);
318
319                 while (bh && bh->b_blocknr) {
320                         atomic_inc(&bitmap->pending_writes);
321                         set_buffer_locked(bh);
322                         set_buffer_mapped(bh);
323                         submit_bh(WRITE, bh);
324                         bh = bh->b_this_page;
325                 }
326
327                 if (wait) {
328                         wait_event(bitmap->write_wait,
329                                    atomic_read(&bitmap->pending_writes)==0);
330                 }
331         }
332         if (bitmap->flags & BITMAP_WRITE_ERROR)
333                 bitmap_file_kick(bitmap);
334 }
335
336 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
337 {
338         struct bitmap *bitmap = bh->b_private;
339         unsigned long flags;
340
341         if (!uptodate) {
342                 spin_lock_irqsave(&bitmap->lock, flags);
343                 bitmap->flags |= BITMAP_WRITE_ERROR;
344                 spin_unlock_irqrestore(&bitmap->lock, flags);
345         }
346         if (atomic_dec_and_test(&bitmap->pending_writes))
347                 wake_up(&bitmap->write_wait);
348 }
349
350 /* copied from buffer.c */
351 static void
352 __clear_page_buffers(struct page *page)
353 {
354         ClearPagePrivate(page);
355         set_page_private(page, 0);
356         page_cache_release(page);
357 }
358 static void free_buffers(struct page *page)
359 {
360         struct buffer_head *bh = page_buffers(page);
361
362         while (bh) {
363                 struct buffer_head *next = bh->b_this_page;
364                 free_buffer_head(bh);
365                 bh = next;
366         }
367         __clear_page_buffers(page);
368         put_page(page);
369 }
370
371 /* read a page from a file.
372  * We both read the page, and attach buffers to the page to record the
373  * address of each block (using bmap).  These addresses will be used
374  * to write the block later, completely bypassing the filesystem.
375  * This usage is similar to how swap files are handled, and allows us
376  * to write to a file with no concerns of memory allocation failing.
377  */
378 static struct page *read_page(struct file *file, unsigned long index,
379                               struct bitmap *bitmap,
380                               unsigned long count)
381 {
382         struct page *page = NULL;
383         struct inode *inode = file->f_path.dentry->d_inode;
384         struct buffer_head *bh;
385         sector_t block;
386
387         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
388                         (unsigned long long)index << PAGE_SHIFT);
389
390         page = alloc_page(GFP_KERNEL);
391         if (!page)
392                 page = ERR_PTR(-ENOMEM);
393         if (IS_ERR(page))
394                 goto out;
395
396         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
397         if (!bh) {
398                 put_page(page);
399                 page = ERR_PTR(-ENOMEM);
400                 goto out;
401         }
402         attach_page_buffers(page, bh);
403         block = index << (PAGE_SHIFT - inode->i_blkbits);
404         while (bh) {
405                 if (count == 0)
406                         bh->b_blocknr = 0;
407                 else {
408                         bh->b_blocknr = bmap(inode, block);
409                         if (bh->b_blocknr == 0) {
410                                 /* Cannot use this file! */
411                                 free_buffers(page);
412                                 page = ERR_PTR(-EINVAL);
413                                 goto out;
414                         }
415                         bh->b_bdev = inode->i_sb->s_bdev;
416                         if (count < (1<<inode->i_blkbits))
417                                 count = 0;
418                         else
419                                 count -= (1<<inode->i_blkbits);
420
421                         bh->b_end_io = end_bitmap_write;
422                         bh->b_private = bitmap;
423                         atomic_inc(&bitmap->pending_writes);
424                         set_buffer_locked(bh);
425                         set_buffer_mapped(bh);
426                         submit_bh(READ, bh);
427                 }
428                 block++;
429                 bh = bh->b_this_page;
430         }
431         page->index = index;
432
433         wait_event(bitmap->write_wait,
434                    atomic_read(&bitmap->pending_writes)==0);
435         if (bitmap->flags & BITMAP_WRITE_ERROR) {
436                 free_buffers(page);
437                 page = ERR_PTR(-EIO);
438         }
439 out:
440         if (IS_ERR(page))
441                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
442                         (int)PAGE_SIZE,
443                         (unsigned long long)index << PAGE_SHIFT,
444                         PTR_ERR(page));
445         return page;
446 }
447
448 /*
449  * bitmap file superblock operations
450  */
451
452 /* update the event counter and sync the superblock to disk */
453 void bitmap_update_sb(struct bitmap *bitmap)
454 {
455         bitmap_super_t *sb;
456         unsigned long flags;
457
458         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
459                 return;
460         spin_lock_irqsave(&bitmap->lock, flags);
461         if (!bitmap->sb_page) { /* no superblock */
462                 spin_unlock_irqrestore(&bitmap->lock, flags);
463                 return;
464         }
465         spin_unlock_irqrestore(&bitmap->lock, flags);
466         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
467         sb->events = cpu_to_le64(bitmap->mddev->events);
468         if (!bitmap->mddev->degraded)
469                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
470         kunmap_atomic(sb, KM_USER0);
471         write_page(bitmap, bitmap->sb_page, 1);
472 }
473
474 /* print out the bitmap file superblock */
475 void bitmap_print_sb(struct bitmap *bitmap)
476 {
477         bitmap_super_t *sb;
478
479         if (!bitmap || !bitmap->sb_page)
480                 return;
481         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
482         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
483         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
484         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
485         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
486                                         *(__u32 *)(sb->uuid+0),
487                                         *(__u32 *)(sb->uuid+4),
488                                         *(__u32 *)(sb->uuid+8),
489                                         *(__u32 *)(sb->uuid+12));
490         printk(KERN_DEBUG "        events: %llu\n",
491                         (unsigned long long) le64_to_cpu(sb->events));
492         printk(KERN_DEBUG "events cleared: %llu\n",
493                         (unsigned long long) le64_to_cpu(sb->events_cleared));
494         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
495         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
496         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
497         printk(KERN_DEBUG "     sync size: %llu KB\n",
498                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
499         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
500         kunmap_atomic(sb, KM_USER0);
501 }
502
503 /* read the superblock from the bitmap file and initialize some bitmap fields */
504 static int bitmap_read_sb(struct bitmap *bitmap)
505 {
506         char *reason = NULL;
507         bitmap_super_t *sb;
508         unsigned long chunksize, daemon_sleep, write_behind;
509         unsigned long long events;
510         int err = -EINVAL;
511
512         /* page 0 is the superblock, read it... */
513         if (bitmap->file) {
514                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
515                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
516
517                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
518         } else {
519                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
520         }
521         if (IS_ERR(bitmap->sb_page)) {
522                 err = PTR_ERR(bitmap->sb_page);
523                 bitmap->sb_page = NULL;
524                 return err;
525         }
526
527         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
528
529         chunksize = le32_to_cpu(sb->chunksize);
530         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
531         write_behind = le32_to_cpu(sb->write_behind);
532
533         /* verify that the bitmap-specific fields are valid */
534         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
535                 reason = "bad magic";
536         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
537                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
538                 reason = "unrecognized superblock version";
539         else if (chunksize < PAGE_SIZE)
540                 reason = "bitmap chunksize too small";
541         else if ((1 << ffz(~chunksize)) != chunksize)
542                 reason = "bitmap chunksize not a power of 2";
543         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
544                 reason = "daemon sleep period out of range";
545         else if (write_behind > COUNTER_MAX)
546                 reason = "write-behind limit out of range (0 - 16383)";
547         if (reason) {
548                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
549                         bmname(bitmap), reason);
550                 goto out;
551         }
552
553         /* keep the array size field of the bitmap superblock up to date */
554         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
555
556         if (!bitmap->mddev->persistent)
557                 goto success;
558
559         /*
560          * if we have a persistent array superblock, compare the
561          * bitmap's UUID and event counter to the mddev's
562          */
563         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
564                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
565                         bmname(bitmap));
566                 goto out;
567         }
568         events = le64_to_cpu(sb->events);
569         if (events < bitmap->mddev->events) {
570                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
571                         "-- forcing full recovery\n", bmname(bitmap), events,
572                         (unsigned long long) bitmap->mddev->events);
573                 sb->state |= cpu_to_le32(BITMAP_STALE);
574         }
575 success:
576         /* assign fields using values from superblock */
577         bitmap->chunksize = chunksize;
578         bitmap->daemon_sleep = daemon_sleep;
579         bitmap->daemon_lastrun = jiffies;
580         bitmap->max_write_behind = write_behind;
581         bitmap->flags |= le32_to_cpu(sb->state);
582         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
583                 bitmap->flags |= BITMAP_HOSTENDIAN;
584         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
585         if (sb->state & cpu_to_le32(BITMAP_STALE))
586                 bitmap->events_cleared = bitmap->mddev->events;
587         err = 0;
588 out:
589         kunmap_atomic(sb, KM_USER0);
590         if (err)
591                 bitmap_print_sb(bitmap);
592         return err;
593 }
594
595 enum bitmap_mask_op {
596         MASK_SET,
597         MASK_UNSET
598 };
599
600 /* record the state of the bitmap in the superblock.  Return the old value */
601 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
602                              enum bitmap_mask_op op)
603 {
604         bitmap_super_t *sb;
605         unsigned long flags;
606         int old;
607
608         spin_lock_irqsave(&bitmap->lock, flags);
609         if (!bitmap->sb_page) { /* can't set the state */
610                 spin_unlock_irqrestore(&bitmap->lock, flags);
611                 return 0;
612         }
613         spin_unlock_irqrestore(&bitmap->lock, flags);
614         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
615         old = le32_to_cpu(sb->state) & bits;
616         switch (op) {
617                 case MASK_SET: sb->state |= cpu_to_le32(bits);
618                                 break;
619                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
620                                 break;
621                 default: BUG();
622         }
623         kunmap_atomic(sb, KM_USER0);
624         return old;
625 }
626
627 /*
628  * general bitmap file operations
629  */
630
631 /* calculate the index of the page that contains this bit */
632 static inline unsigned long file_page_index(unsigned long chunk)
633 {
634         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
635 }
636
637 /* calculate the (bit) offset of this bit within a page */
638 static inline unsigned long file_page_offset(unsigned long chunk)
639 {
640         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
641 }
642
643 /*
644  * return a pointer to the page in the filemap that contains the given bit
645  *
646  * this lookup is complicated by the fact that the bitmap sb might be exactly
647  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
648  * 0 or page 1
649  */
650 static inline struct page *filemap_get_page(struct bitmap *bitmap,
651                                         unsigned long chunk)
652 {
653         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
654         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
655 }
656
657
658 static void bitmap_file_unmap(struct bitmap *bitmap)
659 {
660         struct page **map, *sb_page;
661         unsigned long *attr;
662         int pages;
663         unsigned long flags;
664
665         spin_lock_irqsave(&bitmap->lock, flags);
666         map = bitmap->filemap;
667         bitmap->filemap = NULL;
668         attr = bitmap->filemap_attr;
669         bitmap->filemap_attr = NULL;
670         pages = bitmap->file_pages;
671         bitmap->file_pages = 0;
672         sb_page = bitmap->sb_page;
673         bitmap->sb_page = NULL;
674         spin_unlock_irqrestore(&bitmap->lock, flags);
675
676         while (pages--)
677                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
678                         free_buffers(map[pages]);
679         kfree(map);
680         kfree(attr);
681
682         if (sb_page)
683                 free_buffers(sb_page);
684 }
685
686 static void bitmap_file_put(struct bitmap *bitmap)
687 {
688         struct file *file;
689         unsigned long flags;
690
691         spin_lock_irqsave(&bitmap->lock, flags);
692         file = bitmap->file;
693         bitmap->file = NULL;
694         spin_unlock_irqrestore(&bitmap->lock, flags);
695
696         if (file)
697                 wait_event(bitmap->write_wait,
698                            atomic_read(&bitmap->pending_writes)==0);
699         bitmap_file_unmap(bitmap);
700
701         if (file) {
702                 struct inode *inode = file->f_path.dentry->d_inode;
703                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
704                 fput(file);
705         }
706 }
707
708
709 /*
710  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
711  * then it is no longer reliable, so we stop using it and we mark the file
712  * as failed in the superblock
713  */
714 static void bitmap_file_kick(struct bitmap *bitmap)
715 {
716         char *path, *ptr = NULL;
717
718         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
719                 bitmap_update_sb(bitmap);
720
721                 if (bitmap->file) {
722                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
723                         if (path)
724                                 ptr = file_path(bitmap->file, path, PAGE_SIZE);
725
726                         printk(KERN_ALERT
727                               "%s: kicking failed bitmap file %s from array!\n",
728                               bmname(bitmap), ptr ? ptr : "");
729
730                         kfree(path);
731                 } else
732                         printk(KERN_ALERT
733                                "%s: disabling internal bitmap due to errors\n",
734                                bmname(bitmap));
735         }
736
737         bitmap_file_put(bitmap);
738
739         return;
740 }
741
742 enum bitmap_page_attr {
743         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
744         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
745         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
746 };
747
748 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
749                                 enum bitmap_page_attr attr)
750 {
751         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
752 }
753
754 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
755                                 enum bitmap_page_attr attr)
756 {
757         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
758 }
759
760 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
761                                            enum bitmap_page_attr attr)
762 {
763         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
764 }
765
766 /*
767  * bitmap_file_set_bit -- called before performing a write to the md device
768  * to set (and eventually sync) a particular bit in the bitmap file
769  *
770  * we set the bit immediately, then we record the page number so that
771  * when an unplug occurs, we can flush the dirty pages out to disk
772  */
773 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
774 {
775         unsigned long bit;
776         struct page *page;
777         void *kaddr;
778         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
779
780         if (!bitmap->filemap) {
781                 return;
782         }
783
784         page = filemap_get_page(bitmap, chunk);
785         if (!page) return;
786         bit = file_page_offset(chunk);
787
788         /* set the bit */
789         kaddr = kmap_atomic(page, KM_USER0);
790         if (bitmap->flags & BITMAP_HOSTENDIAN)
791                 set_bit(bit, kaddr);
792         else
793                 ext2_set_bit(bit, kaddr);
794         kunmap_atomic(kaddr, KM_USER0);
795         PRINTK("set file bit %lu page %lu\n", bit, page->index);
796
797         /* record page number so it gets flushed to disk when unplug occurs */
798         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
799
800 }
801
802 /* this gets called when the md device is ready to unplug its underlying
803  * (slave) device queues -- before we let any writes go down, we need to
804  * sync the dirty pages of the bitmap file to disk */
805 void bitmap_unplug(struct bitmap *bitmap)
806 {
807         unsigned long i, flags;
808         int dirty, need_write;
809         struct page *page;
810         int wait = 0;
811
812         if (!bitmap)
813                 return;
814
815         /* look at each page to see if there are any set bits that need to be
816          * flushed out to disk */
817         for (i = 0; i < bitmap->file_pages; i++) {
818                 spin_lock_irqsave(&bitmap->lock, flags);
819                 if (!bitmap->filemap) {
820                         spin_unlock_irqrestore(&bitmap->lock, flags);
821                         return;
822                 }
823                 page = bitmap->filemap[i];
824                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
825                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
826                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
827                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
828                 if (dirty)
829                         wait = 1;
830                 spin_unlock_irqrestore(&bitmap->lock, flags);
831
832                 if (dirty | need_write)
833                         write_page(bitmap, page, 0);
834         }
835         if (wait) { /* if any writes were performed, we need to wait on them */
836                 if (bitmap->file)
837                         wait_event(bitmap->write_wait,
838                                    atomic_read(&bitmap->pending_writes)==0);
839                 else
840                         md_super_wait(bitmap->mddev);
841         }
842         if (bitmap->flags & BITMAP_WRITE_ERROR)
843                 bitmap_file_kick(bitmap);
844 }
845
846 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
847 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
848  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
849  * memory mapping of the bitmap file
850  * Special cases:
851  *   if there's no bitmap file, or if the bitmap file had been
852  *   previously kicked from the array, we mark all the bits as
853  *   1's in order to cause a full resync.
854  *
855  * We ignore all bits for sectors that end earlier than 'start'.
856  * This is used when reading an out-of-date bitmap...
857  */
858 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
859 {
860         unsigned long i, chunks, index, oldindex, bit;
861         struct page *page = NULL, *oldpage = NULL;
862         unsigned long num_pages, bit_cnt = 0;
863         struct file *file;
864         unsigned long bytes, offset;
865         int outofdate;
866         int ret = -ENOSPC;
867         void *paddr;
868
869         chunks = bitmap->chunks;
870         file = bitmap->file;
871
872         BUG_ON(!file && !bitmap->offset);
873
874 #ifdef INJECT_FAULTS_3
875         outofdate = 1;
876 #else
877         outofdate = bitmap->flags & BITMAP_STALE;
878 #endif
879         if (outofdate)
880                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
881                         "recovery\n", bmname(bitmap));
882
883         bytes = (chunks + 7) / 8;
884
885         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
886
887         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
888                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
889                         bmname(bitmap),
890                         (unsigned long) i_size_read(file->f_mapping->host),
891                         bytes + sizeof(bitmap_super_t));
892                 goto err;
893         }
894
895         ret = -ENOMEM;
896
897         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
898         if (!bitmap->filemap)
899                 goto err;
900
901         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
902         bitmap->filemap_attr = kzalloc(
903                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
904                 GFP_KERNEL);
905         if (!bitmap->filemap_attr)
906                 goto err;
907
908         oldindex = ~0L;
909
910         for (i = 0; i < chunks; i++) {
911                 int b;
912                 index = file_page_index(i);
913                 bit = file_page_offset(i);
914                 if (index != oldindex) { /* this is a new page, read it in */
915                         int count;
916                         /* unmap the old page, we're done with it */
917                         if (index == num_pages-1)
918                                 count = bytes + sizeof(bitmap_super_t)
919                                         - index * PAGE_SIZE;
920                         else
921                                 count = PAGE_SIZE;
922                         if (index == 0) {
923                                 /*
924                                  * if we're here then the superblock page
925                                  * contains some bits (PAGE_SIZE != sizeof sb)
926                                  * we've already read it in, so just use it
927                                  */
928                                 page = bitmap->sb_page;
929                                 offset = sizeof(bitmap_super_t);
930                         } else if (file) {
931                                 page = read_page(file, index, bitmap, count);
932                                 offset = 0;
933                         } else {
934                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
935                                 offset = 0;
936                         }
937                         if (IS_ERR(page)) { /* read error */
938                                 ret = PTR_ERR(page);
939                                 goto err;
940                         }
941
942                         oldindex = index;
943                         oldpage = page;
944
945                         if (outofdate) {
946                                 /*
947                                  * if bitmap is out of date, dirty the
948                                  * whole page and write it out
949                                  */
950                                 paddr = kmap_atomic(page, KM_USER0);
951                                 memset(paddr + offset, 0xff,
952                                        PAGE_SIZE - offset);
953                                 kunmap_atomic(paddr, KM_USER0);
954                                 write_page(bitmap, page, 1);
955
956                                 ret = -EIO;
957                                 if (bitmap->flags & BITMAP_WRITE_ERROR) {
958                                         /* release, page not in filemap yet */
959                                         put_page(page);
960                                         goto err;
961                                 }
962                         }
963
964                         bitmap->filemap[bitmap->file_pages++] = page;
965                         bitmap->last_page_size = count;
966                 }
967                 paddr = kmap_atomic(page, KM_USER0);
968                 if (bitmap->flags & BITMAP_HOSTENDIAN)
969                         b = test_bit(bit, paddr);
970                 else
971                         b = ext2_test_bit(bit, paddr);
972                 kunmap_atomic(paddr, KM_USER0);
973                 if (b) {
974                         /* if the disk bit is set, set the memory bit */
975                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
976                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
977                                 );
978                         bit_cnt++;
979                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
980                 }
981         }
982
983         /* everything went OK */
984         ret = 0;
985         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
986
987         if (bit_cnt) { /* Kick recovery if any bits were set */
988                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
989                 md_wakeup_thread(bitmap->mddev->thread);
990         }
991
992         printk(KERN_INFO "%s: bitmap initialized from disk: "
993                 "read %lu/%lu pages, set %lu bits\n",
994                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
995
996         return 0;
997
998  err:
999         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1000                bmname(bitmap), ret);
1001         return ret;
1002 }
1003
1004 void bitmap_write_all(struct bitmap *bitmap)
1005 {
1006         /* We don't actually write all bitmap blocks here,
1007          * just flag them as needing to be written
1008          */
1009         int i;
1010
1011         for (i=0; i < bitmap->file_pages; i++)
1012                 set_page_attr(bitmap, bitmap->filemap[i],
1013                               BITMAP_PAGE_NEEDWRITE);
1014 }
1015
1016
1017 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1018 {
1019         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1020         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1021         bitmap->bp[page].count += inc;
1022 /*
1023         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
1024                               (unsigned long long)offset, inc, bitmap->bp[page].count);
1025 */
1026         bitmap_checkfree(bitmap, page);
1027 }
1028 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1029                                             sector_t offset, int *blocks,
1030                                             int create);
1031
1032 /*
1033  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1034  *                      out to disk
1035  */
1036
1037 void bitmap_daemon_work(struct bitmap *bitmap)
1038 {
1039         unsigned long j;
1040         unsigned long flags;
1041         struct page *page = NULL, *lastpage = NULL;
1042         int blocks;
1043         void *paddr;
1044
1045         if (bitmap == NULL)
1046                 return;
1047         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1048                 return;
1049         bitmap->daemon_lastrun = jiffies;
1050
1051         for (j = 0; j < bitmap->chunks; j++) {
1052                 bitmap_counter_t *bmc;
1053                 spin_lock_irqsave(&bitmap->lock, flags);
1054                 if (!bitmap->filemap) {
1055                         /* error or shutdown */
1056                         spin_unlock_irqrestore(&bitmap->lock, flags);
1057                         break;
1058                 }
1059
1060                 page = filemap_get_page(bitmap, j);
1061
1062                 if (page != lastpage) {
1063                         /* skip this page unless it's marked as needing cleaning */
1064                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1065                                 int need_write = test_page_attr(bitmap, page,
1066                                                                 BITMAP_PAGE_NEEDWRITE);
1067                                 if (need_write)
1068                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1069
1070                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1071                                 if (need_write)
1072                                         write_page(bitmap, page, 0);
1073                                 continue;
1074                         }
1075
1076                         /* grab the new page, sync and release the old */
1077                         if (lastpage != NULL) {
1078                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1079                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1080                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1081                                         write_page(bitmap, lastpage, 0);
1082                                 } else {
1083                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1084                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1085                                 }
1086                         } else
1087                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1088                         lastpage = page;
1089 /*
1090                         printk("bitmap clean at page %lu\n", j);
1091 */
1092                         spin_lock_irqsave(&bitmap->lock, flags);
1093                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1094                 }
1095                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1096                                         &blocks, 0);
1097                 if (bmc) {
1098 /*
1099   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1100 */
1101                         if (*bmc == 2) {
1102                                 *bmc=1; /* maybe clear the bit next time */
1103                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1104                         } else if (*bmc == 1) {
1105                                 /* we can clear the bit */
1106                                 *bmc = 0;
1107                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1108                                                   -1);
1109
1110                                 /* clear the bit */
1111                                 paddr = kmap_atomic(page, KM_USER0);
1112                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1113                                         clear_bit(file_page_offset(j), paddr);
1114                                 else
1115                                         ext2_clear_bit(file_page_offset(j), paddr);
1116                                 kunmap_atomic(paddr, KM_USER0);
1117                         }
1118                 }
1119                 spin_unlock_irqrestore(&bitmap->lock, flags);
1120         }
1121
1122         /* now sync the final page */
1123         if (lastpage != NULL) {
1124                 spin_lock_irqsave(&bitmap->lock, flags);
1125                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1126                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1127                         spin_unlock_irqrestore(&bitmap->lock, flags);
1128                         write_page(bitmap, lastpage, 0);
1129                 } else {
1130                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1131                         spin_unlock_irqrestore(&bitmap->lock, flags);
1132                 }
1133         }
1134
1135 }
1136
1137 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1138                                             sector_t offset, int *blocks,
1139                                             int create)
1140 {
1141         /* If 'create', we might release the lock and reclaim it.
1142          * The lock must have been taken with interrupts enabled.
1143          * If !create, we don't release the lock.
1144          */
1145         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1146         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1147         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1148         sector_t csize;
1149
1150         if (bitmap_checkpage(bitmap, page, create) < 0) {
1151                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1152                 *blocks = csize - (offset & (csize- 1));
1153                 return NULL;
1154         }
1155         /* now locked ... */
1156
1157         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1158                 /* should we use the first or second counter field
1159                  * of the hijacked pointer? */
1160                 int hi = (pageoff > PAGE_COUNTER_MASK);
1161                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1162                                           PAGE_COUNTER_SHIFT - 1);
1163                 *blocks = csize - (offset & (csize- 1));
1164                 return  &((bitmap_counter_t *)
1165                           &bitmap->bp[page].map)[hi];
1166         } else { /* page is allocated */
1167                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1168                 *blocks = csize - (offset & (csize- 1));
1169                 return (bitmap_counter_t *)
1170                         &(bitmap->bp[page].map[pageoff]);
1171         }
1172 }
1173
1174 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1175 {
1176         if (!bitmap) return 0;
1177
1178         if (behind) {
1179                 atomic_inc(&bitmap->behind_writes);
1180                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1181                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1182         }
1183
1184         while (sectors) {
1185                 int blocks;
1186                 bitmap_counter_t *bmc;
1187
1188                 spin_lock_irq(&bitmap->lock);
1189                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1190                 if (!bmc) {
1191                         spin_unlock_irq(&bitmap->lock);
1192                         return 0;
1193                 }
1194
1195                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1196                         DEFINE_WAIT(__wait);
1197                         /* note that it is safe to do the prepare_to_wait
1198                          * after the test as long as we do it before dropping
1199                          * the spinlock.
1200                          */
1201                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1202                                         TASK_UNINTERRUPTIBLE);
1203                         spin_unlock_irq(&bitmap->lock);
1204                         blk_unplug(bitmap->mddev->queue);
1205                         schedule();
1206                         finish_wait(&bitmap->overflow_wait, &__wait);
1207                         continue;
1208                 }
1209
1210                 switch(*bmc) {
1211                 case 0:
1212                         bitmap_file_set_bit(bitmap, offset);
1213                         bitmap_count_page(bitmap,offset, 1);
1214                         blk_plug_device(bitmap->mddev->queue);
1215                         /* fall through */
1216                 case 1:
1217                         *bmc = 2;
1218                 }
1219
1220                 (*bmc)++;
1221
1222                 spin_unlock_irq(&bitmap->lock);
1223
1224                 offset += blocks;
1225                 if (sectors > blocks)
1226                         sectors -= blocks;
1227                 else sectors = 0;
1228         }
1229         return 0;
1230 }
1231
1232 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1233                      int success, int behind)
1234 {
1235         if (!bitmap) return;
1236         if (behind) {
1237                 atomic_dec(&bitmap->behind_writes);
1238                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1239                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1240         }
1241
1242         while (sectors) {
1243                 int blocks;
1244                 unsigned long flags;
1245                 bitmap_counter_t *bmc;
1246
1247                 spin_lock_irqsave(&bitmap->lock, flags);
1248                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1249                 if (!bmc) {
1250                         spin_unlock_irqrestore(&bitmap->lock, flags);
1251                         return;
1252                 }
1253
1254                 if (!success && ! (*bmc & NEEDED_MASK))
1255                         *bmc |= NEEDED_MASK;
1256
1257                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1258                         wake_up(&bitmap->overflow_wait);
1259
1260                 (*bmc)--;
1261                 if (*bmc <= 2) {
1262                         set_page_attr(bitmap,
1263                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1264                                       BITMAP_PAGE_CLEAN);
1265                 }
1266                 spin_unlock_irqrestore(&bitmap->lock, flags);
1267                 offset += blocks;
1268                 if (sectors > blocks)
1269                         sectors -= blocks;
1270                 else sectors = 0;
1271         }
1272 }
1273
1274 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1275                         int degraded)
1276 {
1277         bitmap_counter_t *bmc;
1278         int rv;
1279         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1280                 *blocks = 1024;
1281                 return 1; /* always resync if no bitmap */
1282         }
1283         spin_lock_irq(&bitmap->lock);
1284         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1285         rv = 0;
1286         if (bmc) {
1287                 /* locked */
1288                 if (RESYNC(*bmc))
1289                         rv = 1;
1290                 else if (NEEDED(*bmc)) {
1291                         rv = 1;
1292                         if (!degraded) { /* don't set/clear bits if degraded */
1293                                 *bmc |= RESYNC_MASK;
1294                                 *bmc &= ~NEEDED_MASK;
1295                         }
1296                 }
1297         }
1298         spin_unlock_irq(&bitmap->lock);
1299         return rv;
1300 }
1301
1302 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1303 {
1304         bitmap_counter_t *bmc;
1305         unsigned long flags;
1306 /*
1307         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1308 */      if (bitmap == NULL) {
1309                 *blocks = 1024;
1310                 return;
1311         }
1312         spin_lock_irqsave(&bitmap->lock, flags);
1313         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1314         if (bmc == NULL)
1315                 goto unlock;
1316         /* locked */
1317 /*
1318         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1319 */
1320         if (RESYNC(*bmc)) {
1321                 *bmc &= ~RESYNC_MASK;
1322
1323                 if (!NEEDED(*bmc) && aborted)
1324                         *bmc |= NEEDED_MASK;
1325                 else {
1326                         if (*bmc <= 2) {
1327                                 set_page_attr(bitmap,
1328                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1329                                               BITMAP_PAGE_CLEAN);
1330                         }
1331                 }
1332         }
1333  unlock:
1334         spin_unlock_irqrestore(&bitmap->lock, flags);
1335 }
1336
1337 void bitmap_close_sync(struct bitmap *bitmap)
1338 {
1339         /* Sync has finished, and any bitmap chunks that weren't synced
1340          * properly have been aborted.  It remains to us to clear the
1341          * RESYNC bit wherever it is still on
1342          */
1343         sector_t sector = 0;
1344         int blocks;
1345         if (!bitmap)
1346                 return;
1347         while (sector < bitmap->mddev->resync_max_sectors) {
1348                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1349                 sector += blocks;
1350         }
1351 }
1352
1353 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1354 {
1355         sector_t s = 0;
1356         int blocks;
1357
1358         if (!bitmap)
1359                 return;
1360         if (sector == 0) {
1361                 bitmap->last_end_sync = jiffies;
1362                 return;
1363         }
1364         if (time_before(jiffies, (bitmap->last_end_sync
1365                                   + bitmap->daemon_sleep * HZ)))
1366                 return;
1367         wait_event(bitmap->mddev->recovery_wait,
1368                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1369
1370         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1371         s = 0;
1372         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1373                 bitmap_end_sync(bitmap, s, &blocks, 0);
1374                 s += blocks;
1375         }
1376         bitmap->last_end_sync = jiffies;
1377 }
1378
1379 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1380 {
1381         /* For each chunk covered by any of these sectors, set the
1382          * counter to 1 and set resync_needed.  They should all
1383          * be 0 at this point
1384          */
1385
1386         int secs;
1387         bitmap_counter_t *bmc;
1388         spin_lock_irq(&bitmap->lock);
1389         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1390         if (!bmc) {
1391                 spin_unlock_irq(&bitmap->lock);
1392                 return;
1393         }
1394         if (! *bmc) {
1395                 struct page *page;
1396                 *bmc = 1 | (needed?NEEDED_MASK:0);
1397                 bitmap_count_page(bitmap, offset, 1);
1398                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1399                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1400         }
1401         spin_unlock_irq(&bitmap->lock);
1402
1403 }
1404
1405 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1406 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1407 {
1408         unsigned long chunk;
1409
1410         for (chunk = s; chunk <= e; chunk++) {
1411                 sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
1412                 bitmap_set_memory_bits(bitmap, sec, 1);
1413                 bitmap_file_set_bit(bitmap, sec);
1414         }
1415 }
1416
1417 /*
1418  * flush out any pending updates
1419  */
1420 void bitmap_flush(mddev_t *mddev)
1421 {
1422         struct bitmap *bitmap = mddev->bitmap;
1423         int sleep;
1424
1425         if (!bitmap) /* there was no bitmap */
1426                 return;
1427
1428         /* run the daemon_work three time to ensure everything is flushed
1429          * that can be
1430          */
1431         sleep = bitmap->daemon_sleep;
1432         bitmap->daemon_sleep = 0;
1433         bitmap_daemon_work(bitmap);
1434         bitmap_daemon_work(bitmap);
1435         bitmap_daemon_work(bitmap);
1436         bitmap->daemon_sleep = sleep;
1437         bitmap_update_sb(bitmap);
1438 }
1439
1440 /*
1441  * free memory that was allocated
1442  */
1443 static void bitmap_free(struct bitmap *bitmap)
1444 {
1445         unsigned long k, pages;
1446         struct bitmap_page *bp;
1447
1448         if (!bitmap) /* there was no bitmap */
1449                 return;
1450
1451         /* release the bitmap file and kill the daemon */
1452         bitmap_file_put(bitmap);
1453
1454         bp = bitmap->bp;
1455         pages = bitmap->pages;
1456
1457         /* free all allocated memory */
1458
1459         if (bp) /* deallocate the page memory */
1460                 for (k = 0; k < pages; k++)
1461                         if (bp[k].map && !bp[k].hijacked)
1462                                 kfree(bp[k].map);
1463         kfree(bp);
1464         kfree(bitmap);
1465 }
1466 void bitmap_destroy(mddev_t *mddev)
1467 {
1468         struct bitmap *bitmap = mddev->bitmap;
1469
1470         if (!bitmap) /* there was no bitmap */
1471                 return;
1472
1473         mddev->bitmap = NULL; /* disconnect from the md device */
1474         if (mddev->thread)
1475                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1476
1477         bitmap_free(bitmap);
1478 }
1479
1480 /*
1481  * initialize the bitmap structure
1482  * if this returns an error, bitmap_destroy must be called to do clean up
1483  */
1484 int bitmap_create(mddev_t *mddev)
1485 {
1486         struct bitmap *bitmap;
1487         unsigned long blocks = mddev->resync_max_sectors;
1488         unsigned long chunks;
1489         unsigned long pages;
1490         struct file *file = mddev->bitmap_file;
1491         int err;
1492         sector_t start;
1493
1494         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1495
1496         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1497                 return 0;
1498
1499         BUG_ON(file && mddev->bitmap_offset);
1500
1501         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1502         if (!bitmap)
1503                 return -ENOMEM;
1504
1505         spin_lock_init(&bitmap->lock);
1506         atomic_set(&bitmap->pending_writes, 0);
1507         init_waitqueue_head(&bitmap->write_wait);
1508         init_waitqueue_head(&bitmap->overflow_wait);
1509
1510         bitmap->mddev = mddev;
1511
1512         bitmap->file = file;
1513         bitmap->offset = mddev->bitmap_offset;
1514         if (file) {
1515                 get_file(file);
1516                 do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
1517                                       SYNC_FILE_RANGE_WAIT_BEFORE |
1518                                       SYNC_FILE_RANGE_WRITE |
1519                                       SYNC_FILE_RANGE_WAIT_AFTER);
1520         }
1521         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1522         err = bitmap_read_sb(bitmap);
1523         if (err)
1524                 goto error;
1525
1526         bitmap->chunkshift = ffz(~bitmap->chunksize);
1527
1528         /* now that chunksize and chunkshift are set, we can use these macros */
1529         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1530                         CHUNK_BLOCK_RATIO(bitmap);
1531         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1532
1533         BUG_ON(!pages);
1534
1535         bitmap->chunks = chunks;
1536         bitmap->pages = pages;
1537         bitmap->missing_pages = pages;
1538         bitmap->counter_bits = COUNTER_BITS;
1539
1540         bitmap->syncchunk = ~0UL;
1541
1542 #ifdef INJECT_FATAL_FAULT_1
1543         bitmap->bp = NULL;
1544 #else
1545         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1546 #endif
1547         err = -ENOMEM;
1548         if (!bitmap->bp)
1549                 goto error;
1550
1551         /* now that we have some pages available, initialize the in-memory
1552          * bitmap from the on-disk bitmap */
1553         start = 0;
1554         if (mddev->degraded == 0
1555             || bitmap->events_cleared == mddev->events)
1556                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1557                 start = mddev->recovery_cp;
1558         err = bitmap_init_from_disk(bitmap, start);
1559
1560         if (err)
1561                 goto error;
1562
1563         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1564                 pages, bmname(bitmap));
1565
1566         mddev->bitmap = bitmap;
1567
1568         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1569
1570         bitmap_update_sb(bitmap);
1571
1572         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1573
1574  error:
1575         bitmap_free(bitmap);
1576         return err;
1577 }
1578
1579 /* the bitmap API -- for raid personalities */
1580 EXPORT_SYMBOL(bitmap_startwrite);
1581 EXPORT_SYMBOL(bitmap_endwrite);
1582 EXPORT_SYMBOL(bitmap_start_sync);
1583 EXPORT_SYMBOL(bitmap_end_sync);
1584 EXPORT_SYMBOL(bitmap_unplug);
1585 EXPORT_SYMBOL(bitmap_close_sync);
1586 EXPORT_SYMBOL(bitmap_cond_end_sync);