Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6] / 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  * - added bitmap daemon (to asynchronously clear bitmap bits from disk)
11  */
12
13 /*
14  * Still to do:
15  *
16  * flush after percent set rather than just time based. (maybe both).
17  * wait if count gets too high, wake when it drops to half.
18  * allow bitmap to be mirrored with superblock (before or after...)
19  * allow hot-add to re-instate a current device.
20  * allow hot-add of bitmap after quiessing device
21  */
22
23 #include <linux/module.h>
24 #include <linux/version.h>
25 #include <linux/errno.h>
26 #include <linux/slab.h>
27 #include <linux/init.h>
28 #include <linux/config.h>
29 #include <linux/timer.h>
30 #include <linux/sched.h>
31 #include <linux/list.h>
32 #include <linux/file.h>
33 #include <linux/mount.h>
34 #include <linux/buffer_head.h>
35 #include <linux/raid/md.h>
36 #include <linux/raid/bitmap.h>
37
38 /* debug macros */
39
40 #define DEBUG 0
41
42 #if DEBUG
43 /* these are for debugging purposes only! */
44
45 /* define one and only one of these */
46 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
47 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
48 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
49 #define INJECT_FAULTS_4 0 /* undef */
50 #define INJECT_FAULTS_5 0 /* undef */
51 #define INJECT_FAULTS_6 0
52
53 /* if these are defined, the driver will fail! debug only */
54 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
55 #define INJECT_FATAL_FAULT_2 0 /* undef */
56 #define INJECT_FATAL_FAULT_3 0 /* undef */
57 #endif
58
59 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
60 #define DPRINTK(x...) do { } while(0)
61
62 #ifndef PRINTK
63 #  if DEBUG > 0
64 #    define PRINTK(x...) printk(KERN_DEBUG x)
65 #  else
66 #    define PRINTK(x...)
67 #  endif
68 #endif
69
70 static inline char * bmname(struct bitmap *bitmap)
71 {
72         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
73 }
74
75
76 /*
77  * test if the bitmap is active
78  */
79 int bitmap_active(struct bitmap *bitmap)
80 {
81         unsigned long flags;
82         int res = 0;
83
84         if (!bitmap)
85                 return res;
86         spin_lock_irqsave(&bitmap->lock, flags);
87         res = bitmap->flags & BITMAP_ACTIVE;
88         spin_unlock_irqrestore(&bitmap->lock, flags);
89         return res;
90 }
91
92 #define WRITE_POOL_SIZE 256
93 /* mempool for queueing pending writes on the bitmap file */
94 static void *write_pool_alloc(unsigned int gfp_flags, void *data)
95 {
96         return kmalloc(sizeof(struct page_list), gfp_flags);
97 }
98
99 static void write_pool_free(void *ptr, void *data)
100 {
101         kfree(ptr);
102 }
103
104 /*
105  * just a placeholder - calls kmalloc for bitmap pages
106  */
107 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
108 {
109         unsigned char *page;
110
111 #if INJECT_FAULTS_1
112         page = NULL;
113 #else
114         page = kmalloc(PAGE_SIZE, GFP_NOIO);
115 #endif
116         if (!page)
117                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
118         else
119                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
120                         bmname(bitmap), page);
121         return page;
122 }
123
124 /*
125  * for now just a placeholder -- just calls kfree for bitmap pages
126  */
127 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
128 {
129         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
130         kfree(page);
131 }
132
133 /*
134  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
135  *
136  * 1) check to see if this page is allocated, if it's not then try to alloc
137  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
138  *    page pointer directly as a counter
139  *
140  * if we find our page, we increment the page's refcount so that it stays
141  * allocated while we're using it
142  */
143 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
144 {
145         unsigned char *mappage;
146
147         if (page >= bitmap->pages) {
148                 printk(KERN_ALERT
149                         "%s: invalid bitmap page request: %lu (> %lu)\n",
150                         bmname(bitmap), page, bitmap->pages-1);
151                 return -EINVAL;
152         }
153
154
155         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
156                 return 0;
157
158         if (bitmap->bp[page].map) /* page is already allocated, just return */
159                 return 0;
160
161         if (!create)
162                 return -ENOENT;
163
164         spin_unlock_irq(&bitmap->lock);
165
166         /* this page has not been allocated yet */
167
168         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
169                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
170                         bmname(bitmap));
171                 /* failed - set the hijacked flag so that we can use the
172                  * pointer as a counter */
173                 spin_lock_irq(&bitmap->lock);
174                 if (!bitmap->bp[page].map)
175                         bitmap->bp[page].hijacked = 1;
176                 goto out;
177         }
178
179         /* got a page */
180
181         spin_lock_irq(&bitmap->lock);
182
183         /* recheck the page */
184
185         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
186                 /* somebody beat us to getting the page */
187                 bitmap_free_page(bitmap, mappage);
188                 return 0;
189         }
190
191         /* no page was in place and we have one, so install it */
192
193         memset(mappage, 0, PAGE_SIZE);
194         bitmap->bp[page].map = mappage;
195         bitmap->missing_pages--;
196 out:
197         return 0;
198 }
199
200
201 /* if page is completely empty, put it back on the free list, or dealloc it */
202 /* if page was hijacked, unmark the flag so it might get alloced next time */
203 /* Note: lock should be held when calling this */
204 static inline void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
205 {
206         char *ptr;
207
208         if (bitmap->bp[page].count) /* page is still busy */
209                 return;
210
211         /* page is no longer in use, it can be released */
212
213         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
214                 bitmap->bp[page].hijacked = 0;
215                 bitmap->bp[page].map = NULL;
216                 return;
217         }
218
219         /* normal case, free the page */
220
221 #if 0
222 /* actually ... let's not.  We will probably need the page again exactly when
223  * memory is tight and we are flusing to disk
224  */
225         return;
226 #else
227         ptr = bitmap->bp[page].map;
228         bitmap->bp[page].map = NULL;
229         bitmap->missing_pages++;
230         bitmap_free_page(bitmap, ptr);
231         return;
232 #endif
233 }
234
235
236 /*
237  * bitmap file handling - read and write the bitmap file and its superblock
238  */
239
240 /* copy the pathname of a file to a buffer */
241 char *file_path(struct file *file, char *buf, int count)
242 {
243         struct dentry *d;
244         struct vfsmount *v;
245
246         if (!buf)
247                 return NULL;
248
249         d = file->f_dentry;
250         v = file->f_vfsmnt;
251
252         buf = d_path(d, v, buf, count);
253
254         return IS_ERR(buf) ? NULL : buf;
255 }
256
257 /*
258  * basic page I/O operations
259  */
260
261 /* IO operations when bitmap is stored near all superblocks */
262 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
263 {
264         /* choose a good rdev and read the page from there */
265
266         mdk_rdev_t *rdev;
267         struct list_head *tmp;
268         struct page *page = alloc_page(GFP_KERNEL);
269         sector_t target;
270
271         if (!page)
272                 return ERR_PTR(-ENOMEM);
273         do {
274                 ITERATE_RDEV(mddev, rdev, tmp)
275                         if (rdev->in_sync && !rdev->faulty)
276                                 goto found;
277                 return ERR_PTR(-EIO);
278
279         found:
280                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
281
282         } while (!sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ));
283
284         page->index = index;
285         return page;
286 }
287
288 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
289 {
290         mdk_rdev_t *rdev;
291         struct list_head *tmp;
292
293         ITERATE_RDEV(mddev, rdev, tmp)
294                 if (rdev->in_sync && !rdev->faulty)
295                         md_super_write(mddev, rdev,
296                                        (rdev->sb_offset<<1) + offset
297                                        + page->index * (PAGE_SIZE/512),
298                                        PAGE_SIZE,
299                                        page);
300
301         if (wait)
302                 wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
303         return 0;
304 }
305
306 /*
307  * write out a page to a file
308  */
309 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
310 {
311         int ret = -ENOMEM;
312
313         if (bitmap->file == NULL)
314                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
315
316         if (wait)
317                 lock_page(page);
318         else {
319                 if (TestSetPageLocked(page))
320                         return -EAGAIN; /* already locked */
321                 if (PageWriteback(page)) {
322                         unlock_page(page);
323                         return -EAGAIN;
324                 }
325         }
326
327         ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
328         if (!ret)
329                 ret = page->mapping->a_ops->commit_write(NULL, page, 0,
330                         PAGE_SIZE);
331         if (ret) {
332                 unlock_page(page);
333                 return ret;
334         }
335
336         set_page_dirty(page); /* force it to be written out */
337
338         if (!wait) {
339                 /* add to list to be waited for by daemon */
340                 struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
341                 item->page = page;
342                 page_cache_get(page);
343                 spin_lock(&bitmap->write_lock);
344                 list_add(&item->list, &bitmap->complete_pages);
345                 spin_unlock(&bitmap->write_lock);
346                 md_wakeup_thread(bitmap->writeback_daemon);
347         }
348         return write_one_page(page, wait);
349 }
350
351 /* read a page from a file, pinning it into cache, and return bytes_read */
352 static struct page *read_page(struct file *file, unsigned long index,
353                                         unsigned long *bytes_read)
354 {
355         struct inode *inode = file->f_mapping->host;
356         struct page *page = NULL;
357         loff_t isize = i_size_read(inode);
358         unsigned long end_index = isize >> PAGE_CACHE_SHIFT;
359
360         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_CACHE_SIZE,
361                         (unsigned long long)index << PAGE_CACHE_SHIFT);
362
363         page = read_cache_page(inode->i_mapping, index,
364                         (filler_t *)inode->i_mapping->a_ops->readpage, file);
365         if (IS_ERR(page))
366                 goto out;
367         wait_on_page_locked(page);
368         if (!PageUptodate(page) || PageError(page)) {
369                 page_cache_release(page);
370                 page = ERR_PTR(-EIO);
371                 goto out;
372         }
373
374         if (index > end_index) /* we have read beyond EOF */
375                 *bytes_read = 0;
376         else if (index == end_index) /* possible short read */
377                 *bytes_read = isize & ~PAGE_CACHE_MASK;
378         else
379                 *bytes_read = PAGE_CACHE_SIZE; /* got a full page */
380 out:
381         if (IS_ERR(page))
382                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
383                         (int)PAGE_CACHE_SIZE,
384                         (unsigned long long)index << PAGE_CACHE_SHIFT,
385                         PTR_ERR(page));
386         return page;
387 }
388
389 /*
390  * bitmap file superblock operations
391  */
392
393 /* update the event counter and sync the superblock to disk */
394 int bitmap_update_sb(struct bitmap *bitmap)
395 {
396         bitmap_super_t *sb;
397         unsigned long flags;
398
399         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
400                 return 0;
401         spin_lock_irqsave(&bitmap->lock, flags);
402         if (!bitmap->sb_page) { /* no superblock */
403                 spin_unlock_irqrestore(&bitmap->lock, flags);
404                 return 0;
405         }
406         spin_unlock_irqrestore(&bitmap->lock, flags);
407         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
408         sb->events = cpu_to_le64(bitmap->mddev->events);
409         if (!bitmap->mddev->degraded)
410                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
411         kunmap(bitmap->sb_page);
412         return write_page(bitmap, bitmap->sb_page, 1);
413 }
414
415 /* print out the bitmap file superblock */
416 void bitmap_print_sb(struct bitmap *bitmap)
417 {
418         bitmap_super_t *sb;
419
420         if (!bitmap || !bitmap->sb_page)
421                 return;
422         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
423         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
424         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
425         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
426         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
427                                         *(__u32 *)(sb->uuid+0),
428                                         *(__u32 *)(sb->uuid+4),
429                                         *(__u32 *)(sb->uuid+8),
430                                         *(__u32 *)(sb->uuid+12));
431         printk(KERN_DEBUG "        events: %llu\n",
432                         (unsigned long long) le64_to_cpu(sb->events));
433         printk(KERN_DEBUG "events cleared: %llu\n",
434                         (unsigned long long) le64_to_cpu(sb->events_cleared));
435         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
436         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
437         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
438         printk(KERN_DEBUG "     sync size: %llu KB\n",
439                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
440         kunmap(bitmap->sb_page);
441 }
442
443 /* read the superblock from the bitmap file and initialize some bitmap fields */
444 static int bitmap_read_sb(struct bitmap *bitmap)
445 {
446         char *reason = NULL;
447         bitmap_super_t *sb;
448         unsigned long chunksize, daemon_sleep;
449         unsigned long bytes_read;
450         unsigned long long events;
451         int err = -EINVAL;
452
453         /* page 0 is the superblock, read it... */
454         if (bitmap->file)
455                 bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
456         else {
457                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
458                 bytes_read = PAGE_SIZE;
459         }
460         if (IS_ERR(bitmap->sb_page)) {
461                 err = PTR_ERR(bitmap->sb_page);
462                 bitmap->sb_page = NULL;
463                 return err;
464         }
465
466         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
467
468         if (bytes_read < sizeof(*sb)) { /* short read */
469                 printk(KERN_INFO "%s: bitmap file superblock truncated\n",
470                         bmname(bitmap));
471                 err = -ENOSPC;
472                 goto out;
473         }
474
475         chunksize = le32_to_cpu(sb->chunksize);
476         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
477
478         /* verify that the bitmap-specific fields are valid */
479         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
480                 reason = "bad magic";
481         else if (sb->version != cpu_to_le32(BITMAP_MAJOR))
482                 reason = "unrecognized superblock version";
483         else if (chunksize < 512 || chunksize > (1024 * 1024 * 4))
484                 reason = "bitmap chunksize out of range (512B - 4MB)";
485         else if ((1 << ffz(~chunksize)) != chunksize)
486                 reason = "bitmap chunksize not a power of 2";
487         else if (daemon_sleep < 1 || daemon_sleep > 15)
488                 reason = "daemon sleep period out of range";
489         if (reason) {
490                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
491                         bmname(bitmap), reason);
492                 goto out;
493         }
494
495         /* keep the array size field of the bitmap superblock up to date */
496         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
497
498         if (!bitmap->mddev->persistent)
499                 goto success;
500
501         /*
502          * if we have a persistent array superblock, compare the
503          * bitmap's UUID and event counter to the mddev's
504          */
505         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
506                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
507                         bmname(bitmap));
508                 goto out;
509         }
510         events = le64_to_cpu(sb->events);
511         if (events < bitmap->mddev->events) {
512                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
513                         "-- forcing full recovery\n", bmname(bitmap), events,
514                         (unsigned long long) bitmap->mddev->events);
515                 sb->state |= BITMAP_STALE;
516         }
517 success:
518         /* assign fields using values from superblock */
519         bitmap->chunksize = chunksize;
520         bitmap->daemon_sleep = daemon_sleep;
521         bitmap->flags |= sb->state;
522         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
523         err = 0;
524 out:
525         kunmap(bitmap->sb_page);
526         if (err)
527                 bitmap_print_sb(bitmap);
528         return err;
529 }
530
531 enum bitmap_mask_op {
532         MASK_SET,
533         MASK_UNSET
534 };
535
536 /* record the state of the bitmap in the superblock */
537 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
538                                 enum bitmap_mask_op op)
539 {
540         bitmap_super_t *sb;
541         unsigned long flags;
542
543         spin_lock_irqsave(&bitmap->lock, flags);
544         if (!bitmap || !bitmap->sb_page) { /* can't set the state */
545                 spin_unlock_irqrestore(&bitmap->lock, flags);
546                 return;
547         }
548         page_cache_get(bitmap->sb_page);
549         spin_unlock_irqrestore(&bitmap->lock, flags);
550         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
551         switch (op) {
552                 case MASK_SET: sb->state |= bits;
553                                 break;
554                 case MASK_UNSET: sb->state &= ~bits;
555                                 break;
556                 default: BUG();
557         }
558         kunmap(bitmap->sb_page);
559         page_cache_release(bitmap->sb_page);
560 }
561
562 /*
563  * general bitmap file operations
564  */
565
566 /* calculate the index of the page that contains this bit */
567 static inline unsigned long file_page_index(unsigned long chunk)
568 {
569         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
570 }
571
572 /* calculate the (bit) offset of this bit within a page */
573 static inline unsigned long file_page_offset(unsigned long chunk)
574 {
575         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
576 }
577
578 /*
579  * return a pointer to the page in the filemap that contains the given bit
580  *
581  * this lookup is complicated by the fact that the bitmap sb might be exactly
582  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
583  * 0 or page 1
584  */
585 static inline struct page *filemap_get_page(struct bitmap *bitmap,
586                                         unsigned long chunk)
587 {
588         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
589 }
590
591
592 static void bitmap_file_unmap(struct bitmap *bitmap)
593 {
594         struct page **map, *sb_page;
595         unsigned long *attr;
596         int pages;
597         unsigned long flags;
598
599         spin_lock_irqsave(&bitmap->lock, flags);
600         map = bitmap->filemap;
601         bitmap->filemap = NULL;
602         attr = bitmap->filemap_attr;
603         bitmap->filemap_attr = NULL;
604         pages = bitmap->file_pages;
605         bitmap->file_pages = 0;
606         sb_page = bitmap->sb_page;
607         bitmap->sb_page = NULL;
608         spin_unlock_irqrestore(&bitmap->lock, flags);
609
610         while (pages--)
611                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
612                         page_cache_release(map[pages]);
613         kfree(map);
614         kfree(attr);
615
616         if (sb_page)
617                 page_cache_release(sb_page);
618 }
619
620 static void bitmap_stop_daemons(struct bitmap *bitmap);
621
622 /* dequeue the next item in a page list -- don't call from irq context */
623 static struct page_list *dequeue_page(struct bitmap *bitmap)
624 {
625         struct page_list *item = NULL;
626         struct list_head *head = &bitmap->complete_pages;
627
628         spin_lock(&bitmap->write_lock);
629         if (list_empty(head))
630                 goto out;
631         item = list_entry(head->prev, struct page_list, list);
632         list_del(head->prev);
633 out:
634         spin_unlock(&bitmap->write_lock);
635         return item;
636 }
637
638 static void drain_write_queues(struct bitmap *bitmap)
639 {
640         struct page_list *item;
641
642         while ((item = dequeue_page(bitmap))) {
643                 /* don't bother to wait */
644                 page_cache_release(item->page);
645                 mempool_free(item, bitmap->write_pool);
646         }
647
648         wake_up(&bitmap->write_wait);
649 }
650
651 static void bitmap_file_put(struct bitmap *bitmap)
652 {
653         struct file *file;
654         struct inode *inode;
655         unsigned long flags;
656
657         spin_lock_irqsave(&bitmap->lock, flags);
658         file = bitmap->file;
659         bitmap->file = NULL;
660         spin_unlock_irqrestore(&bitmap->lock, flags);
661
662         bitmap_stop_daemons(bitmap);
663
664         drain_write_queues(bitmap);
665
666         bitmap_file_unmap(bitmap);
667
668         if (file) {
669                 inode = file->f_mapping->host;
670                 spin_lock(&inode->i_lock);
671                 atomic_set(&inode->i_writecount, 1); /* allow writes again */
672                 spin_unlock(&inode->i_lock);
673                 fput(file);
674         }
675 }
676
677
678 /*
679  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
680  * then it is no longer reliable, so we stop using it and we mark the file
681  * as failed in the superblock
682  */
683 static void bitmap_file_kick(struct bitmap *bitmap)
684 {
685         char *path, *ptr = NULL;
686
687         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
688         bitmap_update_sb(bitmap);
689
690         if (bitmap->file) {
691                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
692                 if (path)
693                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
694
695                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
696                        bmname(bitmap), ptr ? ptr : "");
697
698                 kfree(path);
699         }
700
701         bitmap_file_put(bitmap);
702
703         return;
704 }
705
706 enum bitmap_page_attr {
707         BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
708         BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
709         BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
710 };
711
712 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
713                                 enum bitmap_page_attr attr)
714 {
715         bitmap->filemap_attr[page->index] |= attr;
716 }
717
718 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
719                                 enum bitmap_page_attr attr)
720 {
721         bitmap->filemap_attr[page->index] &= ~attr;
722 }
723
724 static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
725 {
726         return bitmap->filemap_attr[page->index];
727 }
728
729 /*
730  * bitmap_file_set_bit -- called before performing a write to the md device
731  * to set (and eventually sync) a particular bit in the bitmap file
732  *
733  * we set the bit immediately, then we record the page number so that
734  * when an unplug occurs, we can flush the dirty pages out to disk
735  */
736 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
737 {
738         unsigned long bit;
739         struct page *page;
740         void *kaddr;
741         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
742
743         if (!bitmap->filemap) {
744                 return;
745         }
746
747         page = filemap_get_page(bitmap, chunk);
748         bit = file_page_offset(chunk);
749
750
751         /* make sure the page stays cached until it gets written out */
752         if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
753                 page_cache_get(page);
754
755         /* set the bit */
756         kaddr = kmap_atomic(page, KM_USER0);
757         set_bit(bit, kaddr);
758         kunmap_atomic(kaddr, KM_USER0);
759         PRINTK("set file bit %lu page %lu\n", bit, page->index);
760
761         /* record page number so it gets flushed to disk when unplug occurs */
762         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
763
764 }
765
766 /* this gets called when the md device is ready to unplug its underlying
767  * (slave) device queues -- before we let any writes go down, we need to
768  * sync the dirty pages of the bitmap file to disk */
769 int bitmap_unplug(struct bitmap *bitmap)
770 {
771         unsigned long i, attr, flags;
772         struct page *page;
773         int wait = 0;
774         int err;
775
776         if (!bitmap)
777                 return 0;
778
779         /* look at each page to see if there are any set bits that need to be
780          * flushed out to disk */
781         for (i = 0; i < bitmap->file_pages; i++) {
782                 spin_lock_irqsave(&bitmap->lock, flags);
783                 if (!bitmap->filemap) {
784                         spin_unlock_irqrestore(&bitmap->lock, flags);
785                         return 0;
786                 }
787                 page = bitmap->filemap[i];
788                 attr = get_page_attr(bitmap, page);
789                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
790                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
791                 if ((attr & BITMAP_PAGE_DIRTY))
792                         wait = 1;
793                 spin_unlock_irqrestore(&bitmap->lock, flags);
794
795                 if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE)) {
796                         err = write_page(bitmap, page, 0);
797                         if (err == -EAGAIN) {
798                                 if (attr & BITMAP_PAGE_DIRTY)
799                                         err = write_page(bitmap, page, 1);
800                                 else
801                                         err = 0;
802                         }
803                         if (err)
804                                 return 1;
805                 }
806         }
807         if (wait) { /* if any writes were performed, we need to wait on them */
808                 if (bitmap->file) {
809                         spin_lock_irq(&bitmap->write_lock);
810                         wait_event_lock_irq(bitmap->write_wait,
811                                             list_empty(&bitmap->complete_pages), bitmap->write_lock,
812                                             wake_up_process(bitmap->writeback_daemon->tsk));
813                         spin_unlock_irq(&bitmap->write_lock);
814                 } else
815                         wait_event(bitmap->mddev->sb_wait,
816                                    atomic_read(&bitmap->mddev->pending_writes)==0);
817         }
818         return 0;
819 }
820
821 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
822         unsigned long sectors, int in_sync);
823 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
824  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
825  * memory mapping of the bitmap file
826  * Special cases:
827  *   if there's no bitmap file, or if the bitmap file had been
828  *   previously kicked from the array, we mark all the bits as
829  *   1's in order to cause a full resync.
830  */
831 static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
832 {
833         unsigned long i, chunks, index, oldindex, bit;
834         struct page *page = NULL, *oldpage = NULL;
835         unsigned long num_pages, bit_cnt = 0;
836         struct file *file;
837         unsigned long bytes, offset, dummy;
838         int outofdate;
839         int ret = -ENOSPC;
840
841         chunks = bitmap->chunks;
842         file = bitmap->file;
843
844         BUG_ON(!file && !bitmap->offset);
845
846 #if INJECT_FAULTS_3
847         outofdate = 1;
848 #else
849         outofdate = bitmap->flags & BITMAP_STALE;
850 #endif
851         if (outofdate)
852                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
853                         "recovery\n", bmname(bitmap));
854
855         bytes = (chunks + 7) / 8;
856
857         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
858
859         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
860                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
861                         bmname(bitmap),
862                         (unsigned long) i_size_read(file->f_mapping->host),
863                         bytes + sizeof(bitmap_super_t));
864                 goto out;
865         }
866
867         ret = -ENOMEM;
868
869         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
870         if (!bitmap->filemap)
871                 goto out;
872
873         bitmap->filemap_attr = kmalloc(sizeof(long) * num_pages, GFP_KERNEL);
874         if (!bitmap->filemap_attr)
875                 goto out;
876
877         memset(bitmap->filemap_attr, 0, sizeof(long) * num_pages);
878
879         oldindex = ~0L;
880
881         for (i = 0; i < chunks; i++) {
882                 index = file_page_index(i);
883                 bit = file_page_offset(i);
884                 if (index != oldindex) { /* this is a new page, read it in */
885                         /* unmap the old page, we're done with it */
886                         if (oldpage != NULL)
887                                 kunmap(oldpage);
888                         if (index == 0) {
889                                 /*
890                                  * if we're here then the superblock page
891                                  * contains some bits (PAGE_SIZE != sizeof sb)
892                                  * we've already read it in, so just use it
893                                  */
894                                 page = bitmap->sb_page;
895                                 offset = sizeof(bitmap_super_t);
896                         } else if (file) {
897                                 page = read_page(file, index, &dummy);
898                                 offset = 0;
899                         } else {
900                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
901                                 offset = 0;
902                         }
903                         if (IS_ERR(page)) { /* read error */
904                                 ret = PTR_ERR(page);
905                                 goto out;
906                         }
907
908                         oldindex = index;
909                         oldpage = page;
910                         kmap(page);
911
912                         if (outofdate) {
913                                 /*
914                                  * if bitmap is out of date, dirty the
915                                  * whole page and write it out
916                                  */
917                                 memset(page_address(page) + offset, 0xff,
918                                         PAGE_SIZE - offset);
919                                 ret = write_page(bitmap, page, 1);
920                                 if (ret) {
921                                         kunmap(page);
922                                         /* release, page not in filemap yet */
923                                         page_cache_release(page);
924                                         goto out;
925                                 }
926                         }
927
928                         bitmap->filemap[bitmap->file_pages++] = page;
929                 }
930                 if (test_bit(bit, page_address(page))) {
931                         /* if the disk bit is set, set the memory bit */
932                         bitmap_set_memory_bits(bitmap,
933                                         i << CHUNK_BLOCK_SHIFT(bitmap), 1, in_sync);
934                         bit_cnt++;
935                 }
936         }
937
938         /* everything went OK */
939         ret = 0;
940         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
941
942         if (page) /* unmap the last page */
943                 kunmap(page);
944
945         if (bit_cnt) { /* Kick recovery if any bits were set */
946                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
947                 md_wakeup_thread(bitmap->mddev->thread);
948         }
949
950 out:
951         printk(KERN_INFO "%s: bitmap initialized from disk: "
952                 "read %lu/%lu pages, set %lu bits, status: %d\n",
953                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
954
955         return ret;
956 }
957
958 void bitmap_write_all(struct bitmap *bitmap)
959 {
960         /* We don't actually write all bitmap blocks here,
961          * just flag them as needing to be written
962          */
963
964         unsigned long chunks = bitmap->chunks;
965         unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
966         unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
967         while (num_pages--)
968                 bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
969 }
970
971
972 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
973 {
974         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
975         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
976         bitmap->bp[page].count += inc;
977 /*
978         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
979                               (unsigned long long)offset, inc, bitmap->bp[page].count);
980 */
981         bitmap_checkfree(bitmap, page);
982 }
983 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
984                                             sector_t offset, int *blocks,
985                                             int create);
986
987 /*
988  * bitmap daemon -- periodically wakes up to clean bits and flush pages
989  *                      out to disk
990  */
991
992 int bitmap_daemon_work(struct bitmap *bitmap)
993 {
994         unsigned long j;
995         unsigned long flags;
996         struct page *page = NULL, *lastpage = NULL;
997         int err = 0;
998         int blocks;
999         int attr;
1000
1001         if (bitmap == NULL)
1002                 return 0;
1003         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1004                 return 0;
1005         bitmap->daemon_lastrun = jiffies;
1006
1007         for (j = 0; j < bitmap->chunks; j++) {
1008                 bitmap_counter_t *bmc;
1009                 spin_lock_irqsave(&bitmap->lock, flags);
1010                 if (!bitmap->filemap) {
1011                         /* error or shutdown */
1012                         spin_unlock_irqrestore(&bitmap->lock, flags);
1013                         break;
1014                 }
1015
1016                 page = filemap_get_page(bitmap, j);
1017
1018                 if (page != lastpage) {
1019                         /* skip this page unless it's marked as needing cleaning */
1020                         if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
1021                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1022                                         page_cache_get(page);
1023                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1024                                 }
1025                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1026                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1027                                         switch (write_page(bitmap, page, 0)) {
1028                                         case -EAGAIN:
1029                                                 set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1030                                                 break;
1031                                         case 0:
1032                                                 break;
1033                                         default:
1034                                                 bitmap_file_kick(bitmap);
1035                                         }
1036                                         page_cache_release(page);
1037                                 }
1038                                 continue;
1039                         }
1040
1041                         /* grab the new page, sync and release the old */
1042                         page_cache_get(page);
1043                         if (lastpage != NULL) {
1044                                 if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
1045                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1046                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1047                                         err = write_page(bitmap, lastpage, 0);
1048                                         if (err == -EAGAIN) {
1049                                                 err = 0;
1050                                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1051                                         }
1052                                 } else {
1053                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1054                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1055                                 }
1056                                 kunmap(lastpage);
1057                                 page_cache_release(lastpage);
1058                                 if (err)
1059                                         bitmap_file_kick(bitmap);
1060                         } else
1061                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1062                         lastpage = page;
1063                         kmap(page);
1064 /*
1065                         printk("bitmap clean at page %lu\n", j);
1066 */
1067                         spin_lock_irqsave(&bitmap->lock, flags);
1068                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1069                 }
1070                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1071                                         &blocks, 0);
1072                 if (bmc) {
1073 /*
1074   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1075 */
1076                         if (*bmc == 2) {
1077                                 *bmc=1; /* maybe clear the bit next time */
1078                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1079                         } else if (*bmc == 1) {
1080                                 /* we can clear the bit */
1081                                 *bmc = 0;
1082                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1083                                                   -1);
1084
1085                                 /* clear the bit */
1086                                 clear_bit(file_page_offset(j), page_address(page));
1087                         }
1088                 }
1089                 spin_unlock_irqrestore(&bitmap->lock, flags);
1090         }
1091
1092         /* now sync the final page */
1093         if (lastpage != NULL) {
1094                 kunmap(lastpage);
1095                 spin_lock_irqsave(&bitmap->lock, flags);
1096                 if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
1097                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1098                         spin_unlock_irqrestore(&bitmap->lock, flags);
1099                         err = write_page(bitmap, lastpage, 0);
1100                         if (err == -EAGAIN) {
1101                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1102                                 err = 0;
1103                         }
1104                 } else {
1105                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1106                         spin_unlock_irqrestore(&bitmap->lock, flags);
1107                 }
1108
1109                 page_cache_release(lastpage);
1110         }
1111
1112         return err;
1113 }
1114
1115 static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
1116 {
1117         mdk_thread_t *dmn;
1118         unsigned long flags;
1119
1120         /* if no one is waiting on us, we'll free the md thread struct
1121          * and exit, otherwise we let the waiter clean things up */
1122         spin_lock_irqsave(&bitmap->lock, flags);
1123         if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
1124                 *daemon = NULL;
1125                 spin_unlock_irqrestore(&bitmap->lock, flags);
1126                 kfree(dmn);
1127                 complete_and_exit(NULL, 0); /* do_exit not exported */
1128         }
1129         spin_unlock_irqrestore(&bitmap->lock, flags);
1130 }
1131
1132 static void bitmap_writeback_daemon(mddev_t *mddev)
1133 {
1134         struct bitmap *bitmap = mddev->bitmap;
1135         struct page *page;
1136         struct page_list *item;
1137         int err = 0;
1138
1139         if (signal_pending(current)) {
1140                 printk(KERN_INFO
1141                        "%s: bitmap writeback daemon got signal, exiting...\n",
1142                        bmname(bitmap));
1143                 err = -EINTR;
1144                 goto out;
1145         }
1146
1147         PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
1148         /* wait on bitmap page writebacks */
1149         while ((item = dequeue_page(bitmap))) {
1150                 page = item->page;
1151                 mempool_free(item, bitmap->write_pool);
1152                 PRINTK("wait on page writeback: %p\n", page);
1153                 wait_on_page_writeback(page);
1154                 PRINTK("finished page writeback: %p\n", page);
1155
1156                 err = PageError(page);
1157                 page_cache_release(page);
1158                 if (err) {
1159                         printk(KERN_WARNING "%s: bitmap file writeback "
1160                                "failed (page %lu): %d\n",
1161                                bmname(bitmap), page->index, err);
1162                         bitmap_file_kick(bitmap);
1163                         goto out;
1164                 }
1165         }
1166  out:
1167         wake_up(&bitmap->write_wait);
1168         if (err) {
1169                 printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1170                        bmname(bitmap), err);
1171                 daemon_exit(bitmap, &bitmap->writeback_daemon);
1172         }
1173 }
1174
1175 static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
1176                                 void (*func)(mddev_t *), char *name)
1177 {
1178         mdk_thread_t *daemon;
1179         unsigned long flags;
1180         char namebuf[32];
1181
1182         spin_lock_irqsave(&bitmap->lock, flags);
1183         *ptr = NULL;
1184
1185         if (!bitmap->file) /* no need for daemon if there's no backing file */
1186                 goto out_unlock;
1187
1188         spin_unlock_irqrestore(&bitmap->lock, flags);
1189
1190 #if INJECT_FATAL_FAULT_2
1191         daemon = NULL;
1192 #else
1193         sprintf(namebuf, "%%s_%s", name);
1194         daemon = md_register_thread(func, bitmap->mddev, namebuf);
1195 #endif
1196         if (!daemon) {
1197                 printk(KERN_ERR "%s: failed to start bitmap daemon\n",
1198                         bmname(bitmap));
1199                 return -ECHILD;
1200         }
1201
1202         spin_lock_irqsave(&bitmap->lock, flags);
1203         *ptr = daemon;
1204
1205         md_wakeup_thread(daemon); /* start it running */
1206
1207         PRINTK("%s: %s daemon (pid %d) started...\n",
1208                 bmname(bitmap), name, daemon->tsk->pid);
1209 out_unlock:
1210         spin_unlock_irqrestore(&bitmap->lock, flags);
1211         return 0;
1212 }
1213
1214 static int bitmap_start_daemons(struct bitmap *bitmap)
1215 {
1216         int err = bitmap_start_daemon(bitmap, &bitmap->writeback_daemon,
1217                                         bitmap_writeback_daemon, "bitmap_wb");
1218         return err;
1219 }
1220
1221 static void bitmap_stop_daemon(struct bitmap *bitmap, mdk_thread_t **ptr)
1222 {
1223         mdk_thread_t *daemon;
1224         unsigned long flags;
1225
1226         spin_lock_irqsave(&bitmap->lock, flags);
1227         daemon = *ptr;
1228         *ptr = NULL;
1229         spin_unlock_irqrestore(&bitmap->lock, flags);
1230         if (daemon)
1231                 md_unregister_thread(daemon); /* destroy the thread */
1232 }
1233
1234 static void bitmap_stop_daemons(struct bitmap *bitmap)
1235 {
1236         /* the daemons can't stop themselves... they'll just exit instead... */
1237         if (bitmap->writeback_daemon &&
1238             current->pid != bitmap->writeback_daemon->tsk->pid)
1239                 bitmap_stop_daemon(bitmap, &bitmap->writeback_daemon);
1240 }
1241
1242 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1243                                             sector_t offset, int *blocks,
1244                                             int create)
1245 {
1246         /* If 'create', we might release the lock and reclaim it.
1247          * The lock must have been taken with interrupts enabled.
1248          * If !create, we don't release the lock.
1249          */
1250         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1251         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1252         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1253         sector_t csize;
1254
1255         if (bitmap_checkpage(bitmap, page, create) < 0) {
1256                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1257                 *blocks = csize - (offset & (csize- 1));
1258                 return NULL;
1259         }
1260         /* now locked ... */
1261
1262         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1263                 /* should we use the first or second counter field
1264                  * of the hijacked pointer? */
1265                 int hi = (pageoff > PAGE_COUNTER_MASK);
1266                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1267                                           PAGE_COUNTER_SHIFT - 1);
1268                 *blocks = csize - (offset & (csize- 1));
1269                 return  &((bitmap_counter_t *)
1270                           &bitmap->bp[page].map)[hi];
1271         } else { /* page is allocated */
1272                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1273                 *blocks = csize - (offset & (csize- 1));
1274                 return (bitmap_counter_t *)
1275                         &(bitmap->bp[page].map[pageoff]);
1276         }
1277 }
1278
1279 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors)
1280 {
1281         if (!bitmap) return 0;
1282         while (sectors) {
1283                 int blocks;
1284                 bitmap_counter_t *bmc;
1285
1286                 spin_lock_irq(&bitmap->lock);
1287                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1288                 if (!bmc) {
1289                         spin_unlock_irq(&bitmap->lock);
1290                         return 0;
1291                 }
1292
1293                 switch(*bmc) {
1294                 case 0:
1295                         bitmap_file_set_bit(bitmap, offset);
1296                         bitmap_count_page(bitmap,offset, 1);
1297                         blk_plug_device(bitmap->mddev->queue);
1298                         /* fall through */
1299                 case 1:
1300                         *bmc = 2;
1301                 }
1302                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX) BUG();
1303                 (*bmc)++;
1304
1305                 spin_unlock_irq(&bitmap->lock);
1306
1307                 offset += blocks;
1308                 if (sectors > blocks)
1309                         sectors -= blocks;
1310                 else sectors = 0;
1311         }
1312         return 0;
1313 }
1314
1315 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1316                      int success)
1317 {
1318         if (!bitmap) return;
1319         while (sectors) {
1320                 int blocks;
1321                 unsigned long flags;
1322                 bitmap_counter_t *bmc;
1323
1324                 spin_lock_irqsave(&bitmap->lock, flags);
1325                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1326                 if (!bmc) {
1327                         spin_unlock_irqrestore(&bitmap->lock, flags);
1328                         return;
1329                 }
1330
1331                 if (!success && ! (*bmc & NEEDED_MASK))
1332                         *bmc |= NEEDED_MASK;
1333
1334                 (*bmc)--;
1335                 if (*bmc <= 2) {
1336                         set_page_attr(bitmap,
1337                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1338                                       BITMAP_PAGE_CLEAN);
1339                 }
1340                 spin_unlock_irqrestore(&bitmap->lock, flags);
1341                 offset += blocks;
1342                 if (sectors > blocks)
1343                         sectors -= blocks;
1344                 else sectors = 0;
1345         }
1346 }
1347
1348 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1349                         int degraded)
1350 {
1351         bitmap_counter_t *bmc;
1352         int rv;
1353         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1354                 *blocks = 1024;
1355                 return 1; /* always resync if no bitmap */
1356         }
1357         spin_lock_irq(&bitmap->lock);
1358         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1359         rv = 0;
1360         if (bmc) {
1361                 /* locked */
1362                 if (RESYNC(*bmc))
1363                         rv = 1;
1364                 else if (NEEDED(*bmc)) {
1365                         rv = 1;
1366                         if (!degraded) { /* don't set/clear bits if degraded */
1367                                 *bmc |= RESYNC_MASK;
1368                                 *bmc &= ~NEEDED_MASK;
1369                         }
1370                 }
1371         }
1372         spin_unlock_irq(&bitmap->lock);
1373         return rv;
1374 }
1375
1376 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1377 {
1378         bitmap_counter_t *bmc;
1379         unsigned long flags;
1380 /*
1381         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1382 */      if (bitmap == NULL) {
1383                 *blocks = 1024;
1384                 return;
1385         }
1386         spin_lock_irqsave(&bitmap->lock, flags);
1387         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1388         if (bmc == NULL)
1389                 goto unlock;
1390         /* locked */
1391 /*
1392         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1393 */
1394         if (RESYNC(*bmc)) {
1395                 *bmc &= ~RESYNC_MASK;
1396
1397                 if (!NEEDED(*bmc) && aborted)
1398                         *bmc |= NEEDED_MASK;
1399                 else {
1400                         if (*bmc <= 2) {
1401                                 set_page_attr(bitmap,
1402                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1403                                               BITMAP_PAGE_CLEAN);
1404                         }
1405                 }
1406         }
1407  unlock:
1408         spin_unlock_irqrestore(&bitmap->lock, flags);
1409 }
1410
1411 void bitmap_close_sync(struct bitmap *bitmap)
1412 {
1413         /* Sync has finished, and any bitmap chunks that weren't synced
1414          * properly have been aborted.  It remains to us to clear the
1415          * RESYNC bit wherever it is still on
1416          */
1417         sector_t sector = 0;
1418         int blocks;
1419         if (!bitmap) return;
1420         while (sector < bitmap->mddev->resync_max_sectors) {
1421                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1422 /*
1423                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1424                                          (unsigned long long)sector, blocks);
1425 */              sector += blocks;
1426         }
1427 }
1428
1429 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
1430                                    unsigned long sectors, int in_sync)
1431 {
1432         /* For each chunk covered by any of these sectors, set the
1433          * counter to 1 and set resync_needed unless in_sync.  They should all
1434          * be 0 at this point
1435          */
1436         while (sectors) {
1437                 int secs;
1438                 bitmap_counter_t *bmc;
1439                 spin_lock_irq(&bitmap->lock);
1440                 bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1441                 if (!bmc) {
1442                         spin_unlock_irq(&bitmap->lock);
1443                         return;
1444                 }
1445                 if (! *bmc) {
1446                         struct page *page;
1447                         *bmc = 1 | (in_sync? 0 : NEEDED_MASK);
1448                         bitmap_count_page(bitmap, offset, 1);
1449                         page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1450                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1451                 }
1452                 spin_unlock_irq(&bitmap->lock);
1453                 if (sectors > secs)
1454                         sectors -= secs;
1455                 else
1456                         sectors = 0;
1457         }
1458 }
1459
1460 /*
1461  * free memory that was allocated
1462  */
1463 void bitmap_destroy(mddev_t *mddev)
1464 {
1465         unsigned long k, pages;
1466         struct bitmap_page *bp;
1467         struct bitmap *bitmap = mddev->bitmap;
1468
1469         if (!bitmap) /* there was no bitmap */
1470                 return;
1471
1472         mddev->bitmap = NULL; /* disconnect from the md device */
1473
1474         /* release the bitmap file and kill the daemon */
1475         bitmap_file_put(bitmap);
1476
1477         bp = bitmap->bp;
1478         pages = bitmap->pages;
1479
1480         /* free all allocated memory */
1481
1482         mempool_destroy(bitmap->write_pool);
1483
1484         if (bp) /* deallocate the page memory */
1485                 for (k = 0; k < pages; k++)
1486                         if (bp[k].map && !bp[k].hijacked)
1487                                 kfree(bp[k].map);
1488         kfree(bp);
1489         kfree(bitmap);
1490 }
1491
1492 /*
1493  * initialize the bitmap structure
1494  * if this returns an error, bitmap_destroy must be called to do clean up
1495  */
1496 int bitmap_create(mddev_t *mddev)
1497 {
1498         struct bitmap *bitmap;
1499         unsigned long blocks = mddev->resync_max_sectors;
1500         unsigned long chunks;
1501         unsigned long pages;
1502         struct file *file = mddev->bitmap_file;
1503         int err;
1504
1505         BUG_ON(sizeof(bitmap_super_t) != 256);
1506
1507         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1508                 return 0;
1509
1510         BUG_ON(file && mddev->bitmap_offset);
1511
1512         bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
1513         if (!bitmap)
1514                 return -ENOMEM;
1515
1516         memset(bitmap, 0, sizeof(*bitmap));
1517
1518         spin_lock_init(&bitmap->lock);
1519         bitmap->mddev = mddev;
1520         mddev->bitmap = bitmap;
1521
1522         spin_lock_init(&bitmap->write_lock);
1523         INIT_LIST_HEAD(&bitmap->complete_pages);
1524         init_waitqueue_head(&bitmap->write_wait);
1525         bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
1526                                 write_pool_free, NULL);
1527         if (!bitmap->write_pool)
1528                 return -ENOMEM;
1529
1530         bitmap->file = file;
1531         bitmap->offset = mddev->bitmap_offset;
1532         if (file) get_file(file);
1533         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1534         err = bitmap_read_sb(bitmap);
1535         if (err)
1536                 return err;
1537
1538         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1539                                         sizeof(bitmap->chunksize));
1540
1541         /* now that chunksize and chunkshift are set, we can use these macros */
1542         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1543                         CHUNK_BLOCK_RATIO(bitmap);
1544         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1545
1546         BUG_ON(!pages);
1547
1548         bitmap->chunks = chunks;
1549         bitmap->pages = pages;
1550         bitmap->missing_pages = pages;
1551         bitmap->counter_bits = COUNTER_BITS;
1552
1553         bitmap->syncchunk = ~0UL;
1554
1555 #if INJECT_FATAL_FAULT_1
1556         bitmap->bp = NULL;
1557 #else
1558         bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1559 #endif
1560         if (!bitmap->bp)
1561                 return -ENOMEM;
1562         memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));
1563
1564         bitmap->flags |= BITMAP_ACTIVE;
1565
1566         /* now that we have some pages available, initialize the in-memory
1567          * bitmap from the on-disk bitmap */
1568         err = bitmap_init_from_disk(bitmap, mddev->recovery_cp == MaxSector);
1569         if (err)
1570                 return err;
1571
1572         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1573                 pages, bmname(bitmap));
1574
1575         /* kick off the bitmap daemons */
1576         err = bitmap_start_daemons(bitmap);
1577         if (err)
1578                 return err;
1579         return bitmap_update_sb(bitmap);
1580 }
1581
1582 /* the bitmap API -- for raid personalities */
1583 EXPORT_SYMBOL(bitmap_startwrite);
1584 EXPORT_SYMBOL(bitmap_endwrite);
1585 EXPORT_SYMBOL(bitmap_start_sync);
1586 EXPORT_SYMBOL(bitmap_end_sync);
1587 EXPORT_SYMBOL(bitmap_unplug);
1588 EXPORT_SYMBOL(bitmap_close_sync);
1589 EXPORT_SYMBOL(bitmap_daemon_work);