Merge master.kernel.org:/home/rmk/linux-2.6-serial
[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/errno.h>
25 #include <linux/slab.h>
26 #include <linux/init.h>
27 #include <linux/config.h>
28 #include <linux/timer.h>
29 #include <linux/sched.h>
30 #include <linux/list.h>
31 #include <linux/file.h>
32 #include <linux/mount.h>
33 #include <linux/buffer_head.h>
34 #include <linux/raid/md.h>
35 #include <linux/raid/bitmap.h>
36
37 /* debug macros */
38
39 #define DEBUG 0
40
41 #if DEBUG
42 /* these are for debugging purposes only! */
43
44 /* define one and only one of these */
45 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
46 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
47 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
48 #define INJECT_FAULTS_4 0 /* undef */
49 #define INJECT_FAULTS_5 0 /* undef */
50 #define INJECT_FAULTS_6 0
51
52 /* if these are defined, the driver will fail! debug only */
53 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
54 #define INJECT_FATAL_FAULT_2 0 /* undef */
55 #define INJECT_FATAL_FAULT_3 0 /* undef */
56 #endif
57
58 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
59 #define DPRINTK(x...) do { } while(0)
60
61 #ifndef PRINTK
62 #  if DEBUG > 0
63 #    define PRINTK(x...) printk(KERN_DEBUG x)
64 #  else
65 #    define PRINTK(x...)
66 #  endif
67 #endif
68
69 static inline char * bmname(struct bitmap *bitmap)
70 {
71         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
72 }
73
74
75 /*
76  * test if the bitmap is active
77  */
78 int bitmap_active(struct bitmap *bitmap)
79 {
80         unsigned long flags;
81         int res = 0;
82
83         if (!bitmap)
84                 return res;
85         spin_lock_irqsave(&bitmap->lock, flags);
86         res = bitmap->flags & BITMAP_ACTIVE;
87         spin_unlock_irqrestore(&bitmap->lock, flags);
88         return res;
89 }
90
91 #define WRITE_POOL_SIZE 256
92
93 /*
94  * just a placeholder - calls kmalloc for bitmap pages
95  */
96 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
97 {
98         unsigned char *page;
99
100 #ifdef INJECT_FAULTS_1
101         page = NULL;
102 #else
103         page = kmalloc(PAGE_SIZE, GFP_NOIO);
104 #endif
105         if (!page)
106                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
107         else
108                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
109                         bmname(bitmap), page);
110         return page;
111 }
112
113 /*
114  * for now just a placeholder -- just calls kfree for bitmap pages
115  */
116 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
117 {
118         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
119         kfree(page);
120 }
121
122 /*
123  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
124  *
125  * 1) check to see if this page is allocated, if it's not then try to alloc
126  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
127  *    page pointer directly as a counter
128  *
129  * if we find our page, we increment the page's refcount so that it stays
130  * allocated while we're using it
131  */
132 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
133 {
134         unsigned char *mappage;
135
136         if (page >= bitmap->pages) {
137                 printk(KERN_ALERT
138                         "%s: invalid bitmap page request: %lu (> %lu)\n",
139                         bmname(bitmap), page, bitmap->pages-1);
140                 return -EINVAL;
141         }
142
143
144         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
145                 return 0;
146
147         if (bitmap->bp[page].map) /* page is already allocated, just return */
148                 return 0;
149
150         if (!create)
151                 return -ENOENT;
152
153         spin_unlock_irq(&bitmap->lock);
154
155         /* this page has not been allocated yet */
156
157         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
158                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
159                         bmname(bitmap));
160                 /* failed - set the hijacked flag so that we can use the
161                  * pointer as a counter */
162                 spin_lock_irq(&bitmap->lock);
163                 if (!bitmap->bp[page].map)
164                         bitmap->bp[page].hijacked = 1;
165                 goto out;
166         }
167
168         /* got a page */
169
170         spin_lock_irq(&bitmap->lock);
171
172         /* recheck the page */
173
174         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
175                 /* somebody beat us to getting the page */
176                 bitmap_free_page(bitmap, mappage);
177                 return 0;
178         }
179
180         /* no page was in place and we have one, so install it */
181
182         memset(mappage, 0, PAGE_SIZE);
183         bitmap->bp[page].map = mappage;
184         bitmap->missing_pages--;
185 out:
186         return 0;
187 }
188
189
190 /* if page is completely empty, put it back on the free list, or dealloc it */
191 /* if page was hijacked, unmark the flag so it might get alloced next time */
192 /* Note: lock should be held when calling this */
193 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
194 {
195         char *ptr;
196
197         if (bitmap->bp[page].count) /* page is still busy */
198                 return;
199
200         /* page is no longer in use, it can be released */
201
202         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
203                 bitmap->bp[page].hijacked = 0;
204                 bitmap->bp[page].map = NULL;
205                 return;
206         }
207
208         /* normal case, free the page */
209
210 #if 0
211 /* actually ... let's not.  We will probably need the page again exactly when
212  * memory is tight and we are flusing to disk
213  */
214         return;
215 #else
216         ptr = bitmap->bp[page].map;
217         bitmap->bp[page].map = NULL;
218         bitmap->missing_pages++;
219         bitmap_free_page(bitmap, ptr);
220         return;
221 #endif
222 }
223
224
225 /*
226  * bitmap file handling - read and write the bitmap file and its superblock
227  */
228
229 /* copy the pathname of a file to a buffer */
230 char *file_path(struct file *file, char *buf, int count)
231 {
232         struct dentry *d;
233         struct vfsmount *v;
234
235         if (!buf)
236                 return NULL;
237
238         d = file->f_dentry;
239         v = file->f_vfsmnt;
240
241         buf = d_path(d, v, buf, count);
242
243         return IS_ERR(buf) ? NULL : buf;
244 }
245
246 /*
247  * basic page I/O operations
248  */
249
250 /* IO operations when bitmap is stored near all superblocks */
251 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
252 {
253         /* choose a good rdev and read the page from there */
254
255         mdk_rdev_t *rdev;
256         struct list_head *tmp;
257         struct page *page = alloc_page(GFP_KERNEL);
258         sector_t target;
259
260         if (!page)
261                 return ERR_PTR(-ENOMEM);
262
263         ITERATE_RDEV(mddev, rdev, tmp) {
264                 if (! test_bit(In_sync, &rdev->flags)
265                     || test_bit(Faulty, &rdev->flags))
266                         continue;
267
268                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
269
270                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
271                         page->index = index;
272                         return page;
273                 }
274         }
275         return ERR_PTR(-EIO);
276
277 }
278
279 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
280 {
281         mdk_rdev_t *rdev;
282         struct list_head *tmp;
283
284         ITERATE_RDEV(mddev, rdev, tmp)
285                 if (test_bit(In_sync, &rdev->flags)
286                     && !test_bit(Faulty, &rdev->flags))
287                         md_super_write(mddev, rdev,
288                                        (rdev->sb_offset<<1) + offset
289                                        + page->index * (PAGE_SIZE/512),
290                                        PAGE_SIZE,
291                                        page);
292
293         if (wait)
294                 md_super_wait(mddev);
295         return 0;
296 }
297
298 /*
299  * write out a page to a file
300  */
301 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
302 {
303         int ret = -ENOMEM;
304
305         if (bitmap->file == NULL)
306                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
307
308         flush_dcache_page(page); /* make sure visible to anyone reading the file */
309
310         if (wait)
311                 lock_page(page);
312         else {
313                 if (TestSetPageLocked(page))
314                         return -EAGAIN; /* already locked */
315                 if (PageWriteback(page)) {
316                         unlock_page(page);
317                         return -EAGAIN;
318                 }
319         }
320
321         ret = page->mapping->a_ops->prepare_write(bitmap->file, page, 0, PAGE_SIZE);
322         if (!ret)
323                 ret = page->mapping->a_ops->commit_write(bitmap->file, page, 0,
324                         PAGE_SIZE);
325         if (ret) {
326                 unlock_page(page);
327                 return ret;
328         }
329
330         set_page_dirty(page); /* force it to be written out */
331
332         if (!wait) {
333                 /* add to list to be waited for by daemon */
334                 struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
335                 item->page = page;
336                 get_page(page);
337                 spin_lock(&bitmap->write_lock);
338                 list_add(&item->list, &bitmap->complete_pages);
339                 spin_unlock(&bitmap->write_lock);
340                 md_wakeup_thread(bitmap->writeback_daemon);
341         }
342         return write_one_page(page, wait);
343 }
344
345 /* read a page from a file, pinning it into cache, and return bytes_read */
346 static struct page *read_page(struct file *file, unsigned long index,
347                                         unsigned long *bytes_read)
348 {
349         struct inode *inode = file->f_mapping->host;
350         struct page *page = NULL;
351         loff_t isize = i_size_read(inode);
352         unsigned long end_index = isize >> PAGE_SHIFT;
353
354         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
355                         (unsigned long long)index << PAGE_SHIFT);
356
357         page = read_cache_page(inode->i_mapping, index,
358                         (filler_t *)inode->i_mapping->a_ops->readpage, file);
359         if (IS_ERR(page))
360                 goto out;
361         wait_on_page_locked(page);
362         if (!PageUptodate(page) || PageError(page)) {
363                 put_page(page);
364                 page = ERR_PTR(-EIO);
365                 goto out;
366         }
367
368         if (index > end_index) /* we have read beyond EOF */
369                 *bytes_read = 0;
370         else if (index == end_index) /* possible short read */
371                 *bytes_read = isize & ~PAGE_MASK;
372         else
373                 *bytes_read = PAGE_SIZE; /* got a full page */
374 out:
375         if (IS_ERR(page))
376                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
377                         (int)PAGE_SIZE,
378                         (unsigned long long)index << PAGE_SHIFT,
379                         PTR_ERR(page));
380         return page;
381 }
382
383 /*
384  * bitmap file superblock operations
385  */
386
387 /* update the event counter and sync the superblock to disk */
388 int bitmap_update_sb(struct bitmap *bitmap)
389 {
390         bitmap_super_t *sb;
391         unsigned long flags;
392
393         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
394                 return 0;
395         spin_lock_irqsave(&bitmap->lock, flags);
396         if (!bitmap->sb_page) { /* no superblock */
397                 spin_unlock_irqrestore(&bitmap->lock, flags);
398                 return 0;
399         }
400         spin_unlock_irqrestore(&bitmap->lock, flags);
401         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
402         sb->events = cpu_to_le64(bitmap->mddev->events);
403         if (!bitmap->mddev->degraded)
404                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
405         kunmap_atomic(sb, KM_USER0);
406         return write_page(bitmap, bitmap->sb_page, 1);
407 }
408
409 /* print out the bitmap file superblock */
410 void bitmap_print_sb(struct bitmap *bitmap)
411 {
412         bitmap_super_t *sb;
413
414         if (!bitmap || !bitmap->sb_page)
415                 return;
416         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
417         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
418         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
419         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
420         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
421                                         *(__u32 *)(sb->uuid+0),
422                                         *(__u32 *)(sb->uuid+4),
423                                         *(__u32 *)(sb->uuid+8),
424                                         *(__u32 *)(sb->uuid+12));
425         printk(KERN_DEBUG "        events: %llu\n",
426                         (unsigned long long) le64_to_cpu(sb->events));
427         printk(KERN_DEBUG "events cleared: %llu\n",
428                         (unsigned long long) le64_to_cpu(sb->events_cleared));
429         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
430         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
431         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
432         printk(KERN_DEBUG "     sync size: %llu KB\n",
433                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
434         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
435         kunmap_atomic(sb, KM_USER0);
436 }
437
438 /* read the superblock from the bitmap file and initialize some bitmap fields */
439 static int bitmap_read_sb(struct bitmap *bitmap)
440 {
441         char *reason = NULL;
442         bitmap_super_t *sb;
443         unsigned long chunksize, daemon_sleep, write_behind;
444         unsigned long bytes_read;
445         unsigned long long events;
446         int err = -EINVAL;
447
448         /* page 0 is the superblock, read it... */
449         if (bitmap->file)
450                 bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
451         else {
452                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
453                 bytes_read = PAGE_SIZE;
454         }
455         if (IS_ERR(bitmap->sb_page)) {
456                 err = PTR_ERR(bitmap->sb_page);
457                 bitmap->sb_page = NULL;
458                 return err;
459         }
460
461         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
462
463         if (bytes_read < sizeof(*sb)) { /* short read */
464                 printk(KERN_INFO "%s: bitmap file superblock truncated\n",
465                         bmname(bitmap));
466                 err = -ENOSPC;
467                 goto out;
468         }
469
470         chunksize = le32_to_cpu(sb->chunksize);
471         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
472         write_behind = le32_to_cpu(sb->write_behind);
473
474         /* verify that the bitmap-specific fields are valid */
475         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
476                 reason = "bad magic";
477         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
478                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
479                 reason = "unrecognized superblock version";
480         else if (chunksize < PAGE_SIZE)
481                 reason = "bitmap chunksize too small";
482         else if ((1 << ffz(~chunksize)) != chunksize)
483                 reason = "bitmap chunksize not a power of 2";
484         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
485                 reason = "daemon sleep period out of range";
486         else if (write_behind > COUNTER_MAX)
487                 reason = "write-behind limit out of range (0 - 16383)";
488         if (reason) {
489                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
490                         bmname(bitmap), reason);
491                 goto out;
492         }
493
494         /* keep the array size field of the bitmap superblock up to date */
495         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
496
497         if (!bitmap->mddev->persistent)
498                 goto success;
499
500         /*
501          * if we have a persistent array superblock, compare the
502          * bitmap's UUID and event counter to the mddev's
503          */
504         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
505                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
506                         bmname(bitmap));
507                 goto out;
508         }
509         events = le64_to_cpu(sb->events);
510         if (events < bitmap->mddev->events) {
511                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
512                         "-- forcing full recovery\n", bmname(bitmap), events,
513                         (unsigned long long) bitmap->mddev->events);
514                 sb->state |= BITMAP_STALE;
515         }
516 success:
517         /* assign fields using values from superblock */
518         bitmap->chunksize = chunksize;
519         bitmap->daemon_sleep = daemon_sleep;
520         bitmap->daemon_lastrun = jiffies;
521         bitmap->max_write_behind = write_behind;
522         bitmap->flags |= sb->state;
523         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
524                 bitmap->flags |= BITMAP_HOSTENDIAN;
525         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
526         if (sb->state & BITMAP_STALE)
527                 bitmap->events_cleared = bitmap->mddev->events;
528         err = 0;
529 out:
530         kunmap_atomic(sb, KM_USER0);
531         if (err)
532                 bitmap_print_sb(bitmap);
533         return err;
534 }
535
536 enum bitmap_mask_op {
537         MASK_SET,
538         MASK_UNSET
539 };
540
541 /* record the state of the bitmap in the superblock */
542 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
543                                 enum bitmap_mask_op op)
544 {
545         bitmap_super_t *sb;
546         unsigned long flags;
547
548         spin_lock_irqsave(&bitmap->lock, flags);
549         if (!bitmap->sb_page) { /* can't set the state */
550                 spin_unlock_irqrestore(&bitmap->lock, flags);
551                 return;
552         }
553         get_page(bitmap->sb_page);
554         spin_unlock_irqrestore(&bitmap->lock, flags);
555         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
556         switch (op) {
557                 case MASK_SET: sb->state |= bits;
558                                 break;
559                 case MASK_UNSET: sb->state &= ~bits;
560                                 break;
561                 default: BUG();
562         }
563         kunmap_atomic(sb, KM_USER0);
564         put_page(bitmap->sb_page);
565 }
566
567 /*
568  * general bitmap file operations
569  */
570
571 /* calculate the index of the page that contains this bit */
572 static inline unsigned long file_page_index(unsigned long chunk)
573 {
574         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
575 }
576
577 /* calculate the (bit) offset of this bit within a page */
578 static inline unsigned long file_page_offset(unsigned long chunk)
579 {
580         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
581 }
582
583 /*
584  * return a pointer to the page in the filemap that contains the given bit
585  *
586  * this lookup is complicated by the fact that the bitmap sb might be exactly
587  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
588  * 0 or page 1
589  */
590 static inline struct page *filemap_get_page(struct bitmap *bitmap,
591                                         unsigned long chunk)
592 {
593         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
594 }
595
596
597 static void bitmap_file_unmap(struct bitmap *bitmap)
598 {
599         struct page **map, *sb_page;
600         unsigned long *attr;
601         int pages;
602         unsigned long flags;
603
604         spin_lock_irqsave(&bitmap->lock, flags);
605         map = bitmap->filemap;
606         bitmap->filemap = NULL;
607         attr = bitmap->filemap_attr;
608         bitmap->filemap_attr = NULL;
609         pages = bitmap->file_pages;
610         bitmap->file_pages = 0;
611         sb_page = bitmap->sb_page;
612         bitmap->sb_page = NULL;
613         spin_unlock_irqrestore(&bitmap->lock, flags);
614
615         while (pages--)
616                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
617                         put_page(map[pages]);
618         kfree(map);
619         kfree(attr);
620
621         safe_put_page(sb_page);
622 }
623
624 static void bitmap_stop_daemon(struct bitmap *bitmap);
625
626 /* dequeue the next item in a page list -- don't call from irq context */
627 static struct page_list *dequeue_page(struct bitmap *bitmap)
628 {
629         struct page_list *item = NULL;
630         struct list_head *head = &bitmap->complete_pages;
631
632         spin_lock(&bitmap->write_lock);
633         if (list_empty(head))
634                 goto out;
635         item = list_entry(head->prev, struct page_list, list);
636         list_del(head->prev);
637 out:
638         spin_unlock(&bitmap->write_lock);
639         return item;
640 }
641
642 static void drain_write_queues(struct bitmap *bitmap)
643 {
644         struct page_list *item;
645
646         while ((item = dequeue_page(bitmap))) {
647                 /* don't bother to wait */
648                 put_page(item->page);
649                 mempool_free(item, bitmap->write_pool);
650         }
651
652         wake_up(&bitmap->write_wait);
653 }
654
655 static void bitmap_file_put(struct bitmap *bitmap)
656 {
657         struct file *file;
658         struct inode *inode;
659         unsigned long flags;
660
661         spin_lock_irqsave(&bitmap->lock, flags);
662         file = bitmap->file;
663         bitmap->file = NULL;
664         spin_unlock_irqrestore(&bitmap->lock, flags);
665
666         bitmap_stop_daemon(bitmap);
667
668         drain_write_queues(bitmap);
669
670         bitmap_file_unmap(bitmap);
671
672         if (file) {
673                 inode = file->f_mapping->host;
674                 spin_lock(&inode->i_lock);
675                 atomic_set(&inode->i_writecount, 1); /* allow writes again */
676                 spin_unlock(&inode->i_lock);
677                 fput(file);
678         }
679 }
680
681
682 /*
683  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
684  * then it is no longer reliable, so we stop using it and we mark the file
685  * as failed in the superblock
686  */
687 static void bitmap_file_kick(struct bitmap *bitmap)
688 {
689         char *path, *ptr = NULL;
690
691         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
692         bitmap_update_sb(bitmap);
693
694         if (bitmap->file) {
695                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
696                 if (path)
697                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
698
699                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
700                        bmname(bitmap), ptr ? ptr : "");
701
702                 kfree(path);
703         }
704
705         bitmap_file_put(bitmap);
706
707         return;
708 }
709
710 enum bitmap_page_attr {
711         BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
712         BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
713         BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
714 };
715
716 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
717                                 enum bitmap_page_attr attr)
718 {
719         bitmap->filemap_attr[page->index] |= attr;
720 }
721
722 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
723                                 enum bitmap_page_attr attr)
724 {
725         bitmap->filemap_attr[page->index] &= ~attr;
726 }
727
728 static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
729 {
730         return bitmap->filemap_attr[page->index];
731 }
732
733 /*
734  * bitmap_file_set_bit -- called before performing a write to the md device
735  * to set (and eventually sync) a particular bit in the bitmap file
736  *
737  * we set the bit immediately, then we record the page number so that
738  * when an unplug occurs, we can flush the dirty pages out to disk
739  */
740 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
741 {
742         unsigned long bit;
743         struct page *page;
744         void *kaddr;
745         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
746
747         if (!bitmap->filemap) {
748                 return;
749         }
750
751         page = filemap_get_page(bitmap, chunk);
752         bit = file_page_offset(chunk);
753
754
755         /* make sure the page stays cached until it gets written out */
756         if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
757                 get_page(page);
758
759         /* set the bit */
760         kaddr = kmap_atomic(page, KM_USER0);
761         if (bitmap->flags & BITMAP_HOSTENDIAN)
762                 set_bit(bit, kaddr);
763         else
764                 ext2_set_bit(bit, kaddr);
765         kunmap_atomic(kaddr, KM_USER0);
766         PRINTK("set file bit %lu page %lu\n", bit, page->index);
767
768         /* record page number so it gets flushed to disk when unplug occurs */
769         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
770
771 }
772
773 /* this gets called when the md device is ready to unplug its underlying
774  * (slave) device queues -- before we let any writes go down, we need to
775  * sync the dirty pages of the bitmap file to disk */
776 int bitmap_unplug(struct bitmap *bitmap)
777 {
778         unsigned long i, attr, flags;
779         struct page *page;
780         int wait = 0;
781         int err;
782
783         if (!bitmap)
784                 return 0;
785
786         /* look at each page to see if there are any set bits that need to be
787          * flushed out to disk */
788         for (i = 0; i < bitmap->file_pages; i++) {
789                 spin_lock_irqsave(&bitmap->lock, flags);
790                 if (!bitmap->filemap) {
791                         spin_unlock_irqrestore(&bitmap->lock, flags);
792                         return 0;
793                 }
794                 page = bitmap->filemap[i];
795                 attr = get_page_attr(bitmap, page);
796                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
797                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
798                 if ((attr & BITMAP_PAGE_DIRTY))
799                         wait = 1;
800                 spin_unlock_irqrestore(&bitmap->lock, flags);
801
802                 if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE)) {
803                         err = write_page(bitmap, page, 0);
804                         if (err == -EAGAIN) {
805                                 if (attr & BITMAP_PAGE_DIRTY)
806                                         err = write_page(bitmap, page, 1);
807                                 else
808                                         err = 0;
809                         }
810                         if (err)
811                                 return 1;
812                 }
813         }
814         if (wait) { /* if any writes were performed, we need to wait on them */
815                 if (bitmap->file) {
816                         spin_lock_irq(&bitmap->write_lock);
817                         wait_event_lock_irq(bitmap->write_wait,
818                                             list_empty(&bitmap->complete_pages), bitmap->write_lock,
819                                             wake_up_process(bitmap->writeback_daemon->tsk));
820                         spin_unlock_irq(&bitmap->write_lock);
821                 } else
822                         md_super_wait(bitmap->mddev);
823         }
824         return 0;
825 }
826
827 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
828 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
829  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
830  * memory mapping of the bitmap file
831  * Special cases:
832  *   if there's no bitmap file, or if the bitmap file had been
833  *   previously kicked from the array, we mark all the bits as
834  *   1's in order to cause a full resync.
835  *
836  * We ignore all bits for sectors that end earlier than 'start'.
837  * This is used when reading an out-of-date bitmap...
838  */
839 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
840 {
841         unsigned long i, chunks, index, oldindex, bit;
842         struct page *page = NULL, *oldpage = NULL;
843         unsigned long num_pages, bit_cnt = 0;
844         struct file *file;
845         unsigned long bytes, offset, dummy;
846         int outofdate;
847         int ret = -ENOSPC;
848         void *paddr;
849
850         chunks = bitmap->chunks;
851         file = bitmap->file;
852
853         BUG_ON(!file && !bitmap->offset);
854
855 #ifdef INJECT_FAULTS_3
856         outofdate = 1;
857 #else
858         outofdate = bitmap->flags & BITMAP_STALE;
859 #endif
860         if (outofdate)
861                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
862                         "recovery\n", bmname(bitmap));
863
864         bytes = (chunks + 7) / 8;
865
866         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
867
868         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
869                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
870                         bmname(bitmap),
871                         (unsigned long) i_size_read(file->f_mapping->host),
872                         bytes + sizeof(bitmap_super_t));
873                 goto out;
874         }
875
876         ret = -ENOMEM;
877
878         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
879         if (!bitmap->filemap)
880                 goto out;
881
882         bitmap->filemap_attr = kzalloc(sizeof(long) * num_pages, GFP_KERNEL);
883         if (!bitmap->filemap_attr)
884                 goto out;
885
886         oldindex = ~0L;
887
888         for (i = 0; i < chunks; i++) {
889                 int b;
890                 index = file_page_index(i);
891                 bit = file_page_offset(i);
892                 if (index != oldindex) { /* this is a new page, read it in */
893                         /* unmap the old page, we're done with it */
894                         if (index == 0) {
895                                 /*
896                                  * if we're here then the superblock page
897                                  * contains some bits (PAGE_SIZE != sizeof sb)
898                                  * we've already read it in, so just use it
899                                  */
900                                 page = bitmap->sb_page;
901                                 offset = sizeof(bitmap_super_t);
902                         } else if (file) {
903                                 page = read_page(file, index, &dummy);
904                                 offset = 0;
905                         } else {
906                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
907                                 offset = 0;
908                         }
909                         if (IS_ERR(page)) { /* read error */
910                                 ret = PTR_ERR(page);
911                                 goto out;
912                         }
913
914                         oldindex = index;
915                         oldpage = page;
916
917                         if (outofdate) {
918                                 /*
919                                  * if bitmap is out of date, dirty the
920                                  * whole page and write it out
921                                  */
922                                 paddr = kmap_atomic(page, KM_USER0);
923                                 memset(paddr + offset, 0xff,
924                                        PAGE_SIZE - offset);
925                                 kunmap_atomic(paddr, KM_USER0);
926                                 ret = write_page(bitmap, page, 1);
927                                 if (ret) {
928                                         /* release, page not in filemap yet */
929                                         put_page(page);
930                                         goto out;
931                                 }
932                         }
933
934                         bitmap->filemap[bitmap->file_pages++] = page;
935                 }
936                 paddr = kmap_atomic(page, KM_USER0);
937                 if (bitmap->flags & BITMAP_HOSTENDIAN)
938                         b = test_bit(bit, paddr);
939                 else
940                         b = ext2_test_bit(bit, paddr);
941                 kunmap_atomic(paddr, KM_USER0);
942                 if (b) {
943                         /* if the disk bit is set, set the memory bit */
944                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
945                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
946                                 );
947                         bit_cnt++;
948                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
949                 }
950         }
951
952         /* everything went OK */
953         ret = 0;
954         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
955
956         if (bit_cnt) { /* Kick recovery if any bits were set */
957                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
958                 md_wakeup_thread(bitmap->mddev->thread);
959         }
960
961 out:
962         printk(KERN_INFO "%s: bitmap initialized from disk: "
963                 "read %lu/%lu pages, set %lu bits, status: %d\n",
964                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
965
966         return ret;
967 }
968
969 void bitmap_write_all(struct bitmap *bitmap)
970 {
971         /* We don't actually write all bitmap blocks here,
972          * just flag them as needing to be written
973          */
974
975         unsigned long chunks = bitmap->chunks;
976         unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
977         unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
978         while (num_pages--)
979                 bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
980 }
981
982
983 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
984 {
985         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
986         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
987         bitmap->bp[page].count += inc;
988 /*
989         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
990                               (unsigned long long)offset, inc, bitmap->bp[page].count);
991 */
992         bitmap_checkfree(bitmap, page);
993 }
994 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
995                                             sector_t offset, int *blocks,
996                                             int create);
997
998 /*
999  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1000  *                      out to disk
1001  */
1002
1003 int bitmap_daemon_work(struct bitmap *bitmap)
1004 {
1005         unsigned long j;
1006         unsigned long flags;
1007         struct page *page = NULL, *lastpage = NULL;
1008         int err = 0;
1009         int blocks;
1010         int attr;
1011         void *paddr;
1012
1013         if (bitmap == NULL)
1014                 return 0;
1015         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1016                 return 0;
1017         bitmap->daemon_lastrun = jiffies;
1018
1019         for (j = 0; j < bitmap->chunks; j++) {
1020                 bitmap_counter_t *bmc;
1021                 spin_lock_irqsave(&bitmap->lock, flags);
1022                 if (!bitmap->filemap) {
1023                         /* error or shutdown */
1024                         spin_unlock_irqrestore(&bitmap->lock, flags);
1025                         break;
1026                 }
1027
1028                 page = filemap_get_page(bitmap, j);
1029
1030                 if (page != lastpage) {
1031                         /* skip this page unless it's marked as needing cleaning */
1032                         if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
1033                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1034                                         get_page(page);
1035                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1036                                 }
1037                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1038                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1039                                         switch (write_page(bitmap, page, 0)) {
1040                                         case -EAGAIN:
1041                                                 set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1042                                                 break;
1043                                         case 0:
1044                                                 break;
1045                                         default:
1046                                                 bitmap_file_kick(bitmap);
1047                                         }
1048                                         put_page(page);
1049                                 }
1050                                 continue;
1051                         }
1052
1053                         /* grab the new page, sync and release the old */
1054                         get_page(page);
1055                         if (lastpage != NULL) {
1056                                 if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
1057                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1058                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1059                                         err = write_page(bitmap, lastpage, 0);
1060                                         if (err == -EAGAIN) {
1061                                                 err = 0;
1062                                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1063                                         }
1064                                 } else {
1065                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1066                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1067                                 }
1068                                 put_page(lastpage);
1069                                 if (err)
1070                                         bitmap_file_kick(bitmap);
1071                         } else
1072                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1073                         lastpage = page;
1074 /*
1075                         printk("bitmap clean at page %lu\n", j);
1076 */
1077                         spin_lock_irqsave(&bitmap->lock, flags);
1078                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1079                 }
1080                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1081                                         &blocks, 0);
1082                 if (bmc) {
1083 /*
1084   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1085 */
1086                         if (*bmc == 2) {
1087                                 *bmc=1; /* maybe clear the bit next time */
1088                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1089                         } else if (*bmc == 1) {
1090                                 /* we can clear the bit */
1091                                 *bmc = 0;
1092                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1093                                                   -1);
1094
1095                                 /* clear the bit */
1096                                 paddr = kmap_atomic(page, KM_USER0);
1097                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1098                                         clear_bit(file_page_offset(j), paddr);
1099                                 else
1100                                         ext2_clear_bit(file_page_offset(j), paddr);
1101                                 kunmap_atomic(paddr, KM_USER0);
1102                         }
1103                 }
1104                 spin_unlock_irqrestore(&bitmap->lock, flags);
1105         }
1106
1107         /* now sync the final page */
1108         if (lastpage != NULL) {
1109                 spin_lock_irqsave(&bitmap->lock, flags);
1110                 if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
1111                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1112                         spin_unlock_irqrestore(&bitmap->lock, flags);
1113                         err = write_page(bitmap, lastpage, 0);
1114                         if (err == -EAGAIN) {
1115                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1116                                 err = 0;
1117                         }
1118                 } else {
1119                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1120                         spin_unlock_irqrestore(&bitmap->lock, flags);
1121                 }
1122
1123                 put_page(lastpage);
1124         }
1125
1126         return err;
1127 }
1128
1129 static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
1130 {
1131         mdk_thread_t *dmn;
1132         unsigned long flags;
1133
1134         /* if no one is waiting on us, we'll free the md thread struct
1135          * and exit, otherwise we let the waiter clean things up */
1136         spin_lock_irqsave(&bitmap->lock, flags);
1137         if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
1138                 *daemon = NULL;
1139                 spin_unlock_irqrestore(&bitmap->lock, flags);
1140                 kfree(dmn);
1141                 complete_and_exit(NULL, 0); /* do_exit not exported */
1142         }
1143         spin_unlock_irqrestore(&bitmap->lock, flags);
1144 }
1145
1146 static void bitmap_writeback_daemon(mddev_t *mddev)
1147 {
1148         struct bitmap *bitmap = mddev->bitmap;
1149         struct page *page;
1150         struct page_list *item;
1151         int err = 0;
1152
1153         if (signal_pending(current)) {
1154                 printk(KERN_INFO
1155                        "%s: bitmap writeback daemon got signal, exiting...\n",
1156                        bmname(bitmap));
1157                 err = -EINTR;
1158                 goto out;
1159         }
1160         if (bitmap == NULL)
1161                 /* about to be stopped. */
1162                 return;
1163
1164         PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
1165         /* wait on bitmap page writebacks */
1166         while ((item = dequeue_page(bitmap))) {
1167                 page = item->page;
1168                 mempool_free(item, bitmap->write_pool);
1169                 PRINTK("wait on page writeback: %p\n", page);
1170                 wait_on_page_writeback(page);
1171                 PRINTK("finished page writeback: %p\n", page);
1172
1173                 err = PageError(page);
1174                 put_page(page);
1175                 if (err) {
1176                         printk(KERN_WARNING "%s: bitmap file writeback "
1177                                "failed (page %lu): %d\n",
1178                                bmname(bitmap), page->index, err);
1179                         bitmap_file_kick(bitmap);
1180                         goto out;
1181                 }
1182         }
1183  out:
1184         wake_up(&bitmap->write_wait);
1185         if (err) {
1186                 printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1187                        bmname(bitmap), err);
1188                 daemon_exit(bitmap, &bitmap->writeback_daemon);
1189         }
1190 }
1191
1192 static mdk_thread_t *bitmap_start_daemon(struct bitmap *bitmap,
1193                                 void (*func)(mddev_t *), char *name)
1194 {
1195         mdk_thread_t *daemon;
1196         char namebuf[32];
1197
1198 #ifdef INJECT_FATAL_FAULT_2
1199         daemon = NULL;
1200 #else
1201         sprintf(namebuf, "%%s_%s", name);
1202         daemon = md_register_thread(func, bitmap->mddev, namebuf);
1203 #endif
1204         if (!daemon) {
1205                 printk(KERN_ERR "%s: failed to start bitmap daemon\n",
1206                         bmname(bitmap));
1207                 return ERR_PTR(-ECHILD);
1208         }
1209
1210         md_wakeup_thread(daemon); /* start it running */
1211
1212         PRINTK("%s: %s daemon (pid %d) started...\n",
1213                 bmname(bitmap), name, daemon->tsk->pid);
1214
1215         return daemon;
1216 }
1217
1218 static void bitmap_stop_daemon(struct bitmap *bitmap)
1219 {
1220         /* the daemon can't stop itself... it'll just exit instead... */
1221         if (bitmap->writeback_daemon && ! IS_ERR(bitmap->writeback_daemon) &&
1222             current->pid != bitmap->writeback_daemon->tsk->pid) {
1223                 mdk_thread_t *daemon;
1224                 unsigned long flags;
1225
1226                 spin_lock_irqsave(&bitmap->lock, flags);
1227                 daemon = bitmap->writeback_daemon;
1228                 bitmap->writeback_daemon = NULL;
1229                 spin_unlock_irqrestore(&bitmap->lock, flags);
1230                 if (daemon && ! IS_ERR(daemon))
1231                         md_unregister_thread(daemon); /* destroy the thread */
1232         }
1233 }
1234
1235 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1236                                             sector_t offset, int *blocks,
1237                                             int create)
1238 {
1239         /* If 'create', we might release the lock and reclaim it.
1240          * The lock must have been taken with interrupts enabled.
1241          * If !create, we don't release the lock.
1242          */
1243         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1244         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1245         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1246         sector_t csize;
1247
1248         if (bitmap_checkpage(bitmap, page, create) < 0) {
1249                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1250                 *blocks = csize - (offset & (csize- 1));
1251                 return NULL;
1252         }
1253         /* now locked ... */
1254
1255         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1256                 /* should we use the first or second counter field
1257                  * of the hijacked pointer? */
1258                 int hi = (pageoff > PAGE_COUNTER_MASK);
1259                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1260                                           PAGE_COUNTER_SHIFT - 1);
1261                 *blocks = csize - (offset & (csize- 1));
1262                 return  &((bitmap_counter_t *)
1263                           &bitmap->bp[page].map)[hi];
1264         } else { /* page is allocated */
1265                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1266                 *blocks = csize - (offset & (csize- 1));
1267                 return (bitmap_counter_t *)
1268                         &(bitmap->bp[page].map[pageoff]);
1269         }
1270 }
1271
1272 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1273 {
1274         if (!bitmap) return 0;
1275
1276         if (behind) {
1277                 atomic_inc(&bitmap->behind_writes);
1278                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1279                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1280         }
1281
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                 BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
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, int behind)
1317 {
1318         if (!bitmap) return;
1319         if (behind) {
1320                 atomic_dec(&bitmap->behind_writes);
1321                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1322                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1323         }
1324
1325         while (sectors) {
1326                 int blocks;
1327                 unsigned long flags;
1328                 bitmap_counter_t *bmc;
1329
1330                 spin_lock_irqsave(&bitmap->lock, flags);
1331                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1332                 if (!bmc) {
1333                         spin_unlock_irqrestore(&bitmap->lock, flags);
1334                         return;
1335                 }
1336
1337                 if (!success && ! (*bmc & NEEDED_MASK))
1338                         *bmc |= NEEDED_MASK;
1339
1340                 (*bmc)--;
1341                 if (*bmc <= 2) {
1342                         set_page_attr(bitmap,
1343                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1344                                       BITMAP_PAGE_CLEAN);
1345                 }
1346                 spin_unlock_irqrestore(&bitmap->lock, flags);
1347                 offset += blocks;
1348                 if (sectors > blocks)
1349                         sectors -= blocks;
1350                 else sectors = 0;
1351         }
1352 }
1353
1354 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1355                         int degraded)
1356 {
1357         bitmap_counter_t *bmc;
1358         int rv;
1359         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1360                 *blocks = 1024;
1361                 return 1; /* always resync if no bitmap */
1362         }
1363         spin_lock_irq(&bitmap->lock);
1364         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1365         rv = 0;
1366         if (bmc) {
1367                 /* locked */
1368                 if (RESYNC(*bmc))
1369                         rv = 1;
1370                 else if (NEEDED(*bmc)) {
1371                         rv = 1;
1372                         if (!degraded) { /* don't set/clear bits if degraded */
1373                                 *bmc |= RESYNC_MASK;
1374                                 *bmc &= ~NEEDED_MASK;
1375                         }
1376                 }
1377         }
1378         spin_unlock_irq(&bitmap->lock);
1379         return rv;
1380 }
1381
1382 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1383 {
1384         bitmap_counter_t *bmc;
1385         unsigned long flags;
1386 /*
1387         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1388 */      if (bitmap == NULL) {
1389                 *blocks = 1024;
1390                 return;
1391         }
1392         spin_lock_irqsave(&bitmap->lock, flags);
1393         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1394         if (bmc == NULL)
1395                 goto unlock;
1396         /* locked */
1397 /*
1398         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1399 */
1400         if (RESYNC(*bmc)) {
1401                 *bmc &= ~RESYNC_MASK;
1402
1403                 if (!NEEDED(*bmc) && aborted)
1404                         *bmc |= NEEDED_MASK;
1405                 else {
1406                         if (*bmc <= 2) {
1407                                 set_page_attr(bitmap,
1408                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1409                                               BITMAP_PAGE_CLEAN);
1410                         }
1411                 }
1412         }
1413  unlock:
1414         spin_unlock_irqrestore(&bitmap->lock, flags);
1415 }
1416
1417 void bitmap_close_sync(struct bitmap *bitmap)
1418 {
1419         /* Sync has finished, and any bitmap chunks that weren't synced
1420          * properly have been aborted.  It remains to us to clear the
1421          * RESYNC bit wherever it is still on
1422          */
1423         sector_t sector = 0;
1424         int blocks;
1425         if (!bitmap) return;
1426         while (sector < bitmap->mddev->resync_max_sectors) {
1427                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1428 /*
1429                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1430                                          (unsigned long long)sector, blocks);
1431 */              sector += blocks;
1432         }
1433 }
1434
1435 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1436 {
1437         /* For each chunk covered by any of these sectors, set the
1438          * counter to 1 and set resync_needed.  They should all
1439          * be 0 at this point
1440          */
1441
1442         int secs;
1443         bitmap_counter_t *bmc;
1444         spin_lock_irq(&bitmap->lock);
1445         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1446         if (!bmc) {
1447                 spin_unlock_irq(&bitmap->lock);
1448                 return;
1449         }
1450         if (! *bmc) {
1451                 struct page *page;
1452                 *bmc = 1 | (needed?NEEDED_MASK:0);
1453                 bitmap_count_page(bitmap, offset, 1);
1454                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1455                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1456         }
1457         spin_unlock_irq(&bitmap->lock);
1458
1459 }
1460
1461 /*
1462  * flush out any pending updates
1463  */
1464 void bitmap_flush(mddev_t *mddev)
1465 {
1466         struct bitmap *bitmap = mddev->bitmap;
1467         int sleep;
1468
1469         if (!bitmap) /* there was no bitmap */
1470                 return;
1471
1472         /* run the daemon_work three time to ensure everything is flushed
1473          * that can be
1474          */
1475         sleep = bitmap->daemon_sleep;
1476         bitmap->daemon_sleep = 0;
1477         bitmap_daemon_work(bitmap);
1478         bitmap_daemon_work(bitmap);
1479         bitmap_daemon_work(bitmap);
1480         bitmap->daemon_sleep = sleep;
1481         bitmap_update_sb(bitmap);
1482 }
1483
1484 /*
1485  * free memory that was allocated
1486  */
1487 static void bitmap_free(struct bitmap *bitmap)
1488 {
1489         unsigned long k, pages;
1490         struct bitmap_page *bp;
1491
1492         if (!bitmap) /* there was no bitmap */
1493                 return;
1494
1495         /* release the bitmap file and kill the daemon */
1496         bitmap_file_put(bitmap);
1497
1498         bp = bitmap->bp;
1499         pages = bitmap->pages;
1500
1501         /* free all allocated memory */
1502
1503         mempool_destroy(bitmap->write_pool);
1504
1505         if (bp) /* deallocate the page memory */
1506                 for (k = 0; k < pages; k++)
1507                         if (bp[k].map && !bp[k].hijacked)
1508                                 kfree(bp[k].map);
1509         kfree(bp);
1510         kfree(bitmap);
1511 }
1512 void bitmap_destroy(mddev_t *mddev)
1513 {
1514         struct bitmap *bitmap = mddev->bitmap;
1515
1516         if (!bitmap) /* there was no bitmap */
1517                 return;
1518
1519         mddev->bitmap = NULL; /* disconnect from the md device */
1520         if (mddev->thread)
1521                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1522
1523         bitmap_free(bitmap);
1524 }
1525
1526 /*
1527  * initialize the bitmap structure
1528  * if this returns an error, bitmap_destroy must be called to do clean up
1529  */
1530 int bitmap_create(mddev_t *mddev)
1531 {
1532         struct bitmap *bitmap;
1533         unsigned long blocks = mddev->resync_max_sectors;
1534         unsigned long chunks;
1535         unsigned long pages;
1536         struct file *file = mddev->bitmap_file;
1537         int err;
1538         sector_t start;
1539
1540         BUG_ON(sizeof(bitmap_super_t) != 256);
1541
1542         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1543                 return 0;
1544
1545         BUG_ON(file && mddev->bitmap_offset);
1546
1547         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1548         if (!bitmap)
1549                 return -ENOMEM;
1550
1551         spin_lock_init(&bitmap->lock);
1552         bitmap->mddev = mddev;
1553
1554         spin_lock_init(&bitmap->write_lock);
1555         INIT_LIST_HEAD(&bitmap->complete_pages);
1556         init_waitqueue_head(&bitmap->write_wait);
1557         bitmap->write_pool = mempool_create_kmalloc_pool(WRITE_POOL_SIZE,
1558                                                 sizeof(struct page_list));
1559         err = -ENOMEM;
1560         if (!bitmap->write_pool)
1561                 goto error;
1562
1563         bitmap->file = file;
1564         bitmap->offset = mddev->bitmap_offset;
1565         if (file) get_file(file);
1566         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1567         err = bitmap_read_sb(bitmap);
1568         if (err)
1569                 goto error;
1570
1571         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1572                                         sizeof(bitmap->chunksize));
1573
1574         /* now that chunksize and chunkshift are set, we can use these macros */
1575         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1576                         CHUNK_BLOCK_RATIO(bitmap);
1577         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1578
1579         BUG_ON(!pages);
1580
1581         bitmap->chunks = chunks;
1582         bitmap->pages = pages;
1583         bitmap->missing_pages = pages;
1584         bitmap->counter_bits = COUNTER_BITS;
1585
1586         bitmap->syncchunk = ~0UL;
1587
1588 #ifdef INJECT_FATAL_FAULT_1
1589         bitmap->bp = NULL;
1590 #else
1591         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1592 #endif
1593         err = -ENOMEM;
1594         if (!bitmap->bp)
1595                 goto error;
1596
1597         bitmap->flags |= BITMAP_ACTIVE;
1598
1599         /* now that we have some pages available, initialize the in-memory
1600          * bitmap from the on-disk bitmap */
1601         start = 0;
1602         if (mddev->degraded == 0
1603             || bitmap->events_cleared == mddev->events)
1604                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1605                 start = mddev->recovery_cp;
1606         err = bitmap_init_from_disk(bitmap, start);
1607
1608         if (err)
1609                 goto error;
1610
1611         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1612                 pages, bmname(bitmap));
1613
1614         mddev->bitmap = bitmap;
1615
1616         if (file)
1617                 /* kick off the bitmap writeback daemon */
1618                 bitmap->writeback_daemon =
1619                         bitmap_start_daemon(bitmap,
1620                                             bitmap_writeback_daemon,
1621                                             "bitmap_wb");
1622
1623         if (IS_ERR(bitmap->writeback_daemon))
1624                 return PTR_ERR(bitmap->writeback_daemon);
1625         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1626
1627         return bitmap_update_sb(bitmap);
1628
1629  error:
1630         bitmap_free(bitmap);
1631         return err;
1632 }
1633
1634 /* the bitmap API -- for raid personalities */
1635 EXPORT_SYMBOL(bitmap_startwrite);
1636 EXPORT_SYMBOL(bitmap_endwrite);
1637 EXPORT_SYMBOL(bitmap_start_sync);
1638 EXPORT_SYMBOL(bitmap_end_sync);
1639 EXPORT_SYMBOL(bitmap_unplug);
1640 EXPORT_SYMBOL(bitmap_close_sync);
1641 EXPORT_SYMBOL(bitmap_daemon_work);