[PATCH] gfp_t: remaining bits of drivers/*
[linux-2.6.git] / drivers / md / bitmap.c
1 /*
2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
3  *
4  * bitmap_create  - sets up the bitmap structure
5  * bitmap_destroy - destroys the bitmap structure
6  *
7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
8  * - added disk storage for bitmap
9  * - changes to allow various bitmap chunk sizes
10  * - 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(gfp_t 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 #ifdef 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
274         ITERATE_RDEV(mddev, rdev, tmp) {
275                 if (! rdev->in_sync || rdev->faulty)
276                         continue;
277
278                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
279
280                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
281                         page->index = index;
282                         return page;
283                 }
284         }
285         return ERR_PTR(-EIO);
286
287 }
288
289 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
290 {
291         mdk_rdev_t *rdev;
292         struct list_head *tmp;
293
294         ITERATE_RDEV(mddev, rdev, tmp)
295                 if (rdev->in_sync && !rdev->faulty)
296                         md_super_write(mddev, rdev,
297                                        (rdev->sb_offset<<1) + offset
298                                        + page->index * (PAGE_SIZE/512),
299                                        PAGE_SIZE,
300                                        page);
301
302         if (wait)
303                 wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
304         return 0;
305 }
306
307 /*
308  * write out a page to a file
309  */
310 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
311 {
312         int ret = -ENOMEM;
313
314         if (bitmap->file == NULL)
315                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
316
317         if (wait)
318                 lock_page(page);
319         else {
320                 if (TestSetPageLocked(page))
321                         return -EAGAIN; /* already locked */
322                 if (PageWriteback(page)) {
323                         unlock_page(page);
324                         return -EAGAIN;
325                 }
326         }
327
328         ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
329         if (!ret)
330                 ret = page->mapping->a_ops->commit_write(NULL, page, 0,
331                         PAGE_SIZE);
332         if (ret) {
333                 unlock_page(page);
334                 return ret;
335         }
336
337         set_page_dirty(page); /* force it to be written out */
338
339         if (!wait) {
340                 /* add to list to be waited for by daemon */
341                 struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
342                 item->page = page;
343                 page_cache_get(page);
344                 spin_lock(&bitmap->write_lock);
345                 list_add(&item->list, &bitmap->complete_pages);
346                 spin_unlock(&bitmap->write_lock);
347                 md_wakeup_thread(bitmap->writeback_daemon);
348         }
349         return write_one_page(page, wait);
350 }
351
352 /* read a page from a file, pinning it into cache, and return bytes_read */
353 static struct page *read_page(struct file *file, unsigned long index,
354                                         unsigned long *bytes_read)
355 {
356         struct inode *inode = file->f_mapping->host;
357         struct page *page = NULL;
358         loff_t isize = i_size_read(inode);
359         unsigned long end_index = isize >> PAGE_CACHE_SHIFT;
360
361         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_CACHE_SIZE,
362                         (unsigned long long)index << PAGE_CACHE_SHIFT);
363
364         page = read_cache_page(inode->i_mapping, index,
365                         (filler_t *)inode->i_mapping->a_ops->readpage, file);
366         if (IS_ERR(page))
367                 goto out;
368         wait_on_page_locked(page);
369         if (!PageUptodate(page) || PageError(page)) {
370                 page_cache_release(page);
371                 page = ERR_PTR(-EIO);
372                 goto out;
373         }
374
375         if (index > end_index) /* we have read beyond EOF */
376                 *bytes_read = 0;
377         else if (index == end_index) /* possible short read */
378                 *bytes_read = isize & ~PAGE_CACHE_MASK;
379         else
380                 *bytes_read = PAGE_CACHE_SIZE; /* got a full page */
381 out:
382         if (IS_ERR(page))
383                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
384                         (int)PAGE_CACHE_SIZE,
385                         (unsigned long long)index << PAGE_CACHE_SHIFT,
386                         PTR_ERR(page));
387         return page;
388 }
389
390 /*
391  * bitmap file superblock operations
392  */
393
394 /* update the event counter and sync the superblock to disk */
395 int bitmap_update_sb(struct bitmap *bitmap)
396 {
397         bitmap_super_t *sb;
398         unsigned long flags;
399
400         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
401                 return 0;
402         spin_lock_irqsave(&bitmap->lock, flags);
403         if (!bitmap->sb_page) { /* no superblock */
404                 spin_unlock_irqrestore(&bitmap->lock, flags);
405                 return 0;
406         }
407         spin_unlock_irqrestore(&bitmap->lock, flags);
408         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
409         sb->events = cpu_to_le64(bitmap->mddev->events);
410         if (!bitmap->mddev->degraded)
411                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
412         kunmap(bitmap->sb_page);
413         return write_page(bitmap, bitmap->sb_page, 1);
414 }
415
416 /* print out the bitmap file superblock */
417 void bitmap_print_sb(struct bitmap *bitmap)
418 {
419         bitmap_super_t *sb;
420
421         if (!bitmap || !bitmap->sb_page)
422                 return;
423         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
424         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
425         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
426         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
427         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
428                                         *(__u32 *)(sb->uuid+0),
429                                         *(__u32 *)(sb->uuid+4),
430                                         *(__u32 *)(sb->uuid+8),
431                                         *(__u32 *)(sb->uuid+12));
432         printk(KERN_DEBUG "        events: %llu\n",
433                         (unsigned long long) le64_to_cpu(sb->events));
434         printk(KERN_DEBUG "events cleared: %llu\n",
435                         (unsigned long long) le64_to_cpu(sb->events_cleared));
436         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
437         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
438         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
439         printk(KERN_DEBUG "     sync size: %llu KB\n",
440                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
441         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
442         kunmap(bitmap->sb_page);
443 }
444
445 /* read the superblock from the bitmap file and initialize some bitmap fields */
446 static int bitmap_read_sb(struct bitmap *bitmap)
447 {
448         char *reason = NULL;
449         bitmap_super_t *sb;
450         unsigned long chunksize, daemon_sleep, write_behind;
451         unsigned long bytes_read;
452         unsigned long long events;
453         int err = -EINVAL;
454
455         /* page 0 is the superblock, read it... */
456         if (bitmap->file)
457                 bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
458         else {
459                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
460                 bytes_read = PAGE_SIZE;
461         }
462         if (IS_ERR(bitmap->sb_page)) {
463                 err = PTR_ERR(bitmap->sb_page);
464                 bitmap->sb_page = NULL;
465                 return err;
466         }
467
468         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
469
470         if (bytes_read < sizeof(*sb)) { /* short read */
471                 printk(KERN_INFO "%s: bitmap file superblock truncated\n",
472                         bmname(bitmap));
473                 err = -ENOSPC;
474                 goto out;
475         }
476
477         chunksize = le32_to_cpu(sb->chunksize);
478         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
479         write_behind = le32_to_cpu(sb->write_behind);
480
481         /* verify that the bitmap-specific fields are valid */
482         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
483                 reason = "bad magic";
484         else if (sb->version != cpu_to_le32(BITMAP_MAJOR))
485                 reason = "unrecognized superblock version";
486         else if (chunksize < 512 || chunksize > (1024 * 1024 * 4))
487                 reason = "bitmap chunksize out of range (512B - 4MB)";
488         else if ((1 << ffz(~chunksize)) != chunksize)
489                 reason = "bitmap chunksize not a power of 2";
490         else if (daemon_sleep < 1 || daemon_sleep > 15)
491                 reason = "daemon sleep period out of range (1-15s)";
492         else if (write_behind > COUNTER_MAX)
493                 reason = "write-behind limit out of range (0 - 16383)";
494         if (reason) {
495                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
496                         bmname(bitmap), reason);
497                 goto out;
498         }
499
500         /* keep the array size field of the bitmap superblock up to date */
501         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
502
503         if (!bitmap->mddev->persistent)
504                 goto success;
505
506         /*
507          * if we have a persistent array superblock, compare the
508          * bitmap's UUID and event counter to the mddev's
509          */
510         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
511                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
512                         bmname(bitmap));
513                 goto out;
514         }
515         events = le64_to_cpu(sb->events);
516         if (events < bitmap->mddev->events) {
517                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
518                         "-- forcing full recovery\n", bmname(bitmap), events,
519                         (unsigned long long) bitmap->mddev->events);
520                 sb->state |= BITMAP_STALE;
521         }
522 success:
523         /* assign fields using values from superblock */
524         bitmap->chunksize = chunksize;
525         bitmap->daemon_sleep = daemon_sleep;
526         bitmap->daemon_lastrun = jiffies;
527         bitmap->max_write_behind = write_behind;
528         bitmap->flags |= sb->state;
529         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
530         if (sb->state & BITMAP_STALE)
531                 bitmap->events_cleared = bitmap->mddev->events;
532         err = 0;
533 out:
534         kunmap(bitmap->sb_page);
535         if (err)
536                 bitmap_print_sb(bitmap);
537         return err;
538 }
539
540 enum bitmap_mask_op {
541         MASK_SET,
542         MASK_UNSET
543 };
544
545 /* record the state of the bitmap in the superblock */
546 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
547                                 enum bitmap_mask_op op)
548 {
549         bitmap_super_t *sb;
550         unsigned long flags;
551
552         spin_lock_irqsave(&bitmap->lock, flags);
553         if (!bitmap || !bitmap->sb_page) { /* can't set the state */
554                 spin_unlock_irqrestore(&bitmap->lock, flags);
555                 return;
556         }
557         page_cache_get(bitmap->sb_page);
558         spin_unlock_irqrestore(&bitmap->lock, flags);
559         sb = (bitmap_super_t *)kmap(bitmap->sb_page);
560         switch (op) {
561                 case MASK_SET: sb->state |= bits;
562                                 break;
563                 case MASK_UNSET: sb->state &= ~bits;
564                                 break;
565                 default: BUG();
566         }
567         kunmap(bitmap->sb_page);
568         page_cache_release(bitmap->sb_page);
569 }
570
571 /*
572  * general bitmap file operations
573  */
574
575 /* calculate the index of the page that contains this bit */
576 static inline unsigned long file_page_index(unsigned long chunk)
577 {
578         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
579 }
580
581 /* calculate the (bit) offset of this bit within a page */
582 static inline unsigned long file_page_offset(unsigned long chunk)
583 {
584         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
585 }
586
587 /*
588  * return a pointer to the page in the filemap that contains the given bit
589  *
590  * this lookup is complicated by the fact that the bitmap sb might be exactly
591  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
592  * 0 or page 1
593  */
594 static inline struct page *filemap_get_page(struct bitmap *bitmap,
595                                         unsigned long chunk)
596 {
597         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
598 }
599
600
601 static void bitmap_file_unmap(struct bitmap *bitmap)
602 {
603         struct page **map, *sb_page;
604         unsigned long *attr;
605         int pages;
606         unsigned long flags;
607
608         spin_lock_irqsave(&bitmap->lock, flags);
609         map = bitmap->filemap;
610         bitmap->filemap = NULL;
611         attr = bitmap->filemap_attr;
612         bitmap->filemap_attr = NULL;
613         pages = bitmap->file_pages;
614         bitmap->file_pages = 0;
615         sb_page = bitmap->sb_page;
616         bitmap->sb_page = NULL;
617         spin_unlock_irqrestore(&bitmap->lock, flags);
618
619         while (pages--)
620                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
621                         page_cache_release(map[pages]);
622         kfree(map);
623         kfree(attr);
624
625         if (sb_page)
626                 page_cache_release(sb_page);
627 }
628
629 static void bitmap_stop_daemon(struct bitmap *bitmap);
630
631 /* dequeue the next item in a page list -- don't call from irq context */
632 static struct page_list *dequeue_page(struct bitmap *bitmap)
633 {
634         struct page_list *item = NULL;
635         struct list_head *head = &bitmap->complete_pages;
636
637         spin_lock(&bitmap->write_lock);
638         if (list_empty(head))
639                 goto out;
640         item = list_entry(head->prev, struct page_list, list);
641         list_del(head->prev);
642 out:
643         spin_unlock(&bitmap->write_lock);
644         return item;
645 }
646
647 static void drain_write_queues(struct bitmap *bitmap)
648 {
649         struct page_list *item;
650
651         while ((item = dequeue_page(bitmap))) {
652                 /* don't bother to wait */
653                 page_cache_release(item->page);
654                 mempool_free(item, bitmap->write_pool);
655         }
656
657         wake_up(&bitmap->write_wait);
658 }
659
660 static void bitmap_file_put(struct bitmap *bitmap)
661 {
662         struct file *file;
663         struct inode *inode;
664         unsigned long flags;
665
666         spin_lock_irqsave(&bitmap->lock, flags);
667         file = bitmap->file;
668         bitmap->file = NULL;
669         spin_unlock_irqrestore(&bitmap->lock, flags);
670
671         bitmap_stop_daemon(bitmap);
672
673         drain_write_queues(bitmap);
674
675         bitmap_file_unmap(bitmap);
676
677         if (file) {
678                 inode = file->f_mapping->host;
679                 spin_lock(&inode->i_lock);
680                 atomic_set(&inode->i_writecount, 1); /* allow writes again */
681                 spin_unlock(&inode->i_lock);
682                 fput(file);
683         }
684 }
685
686
687 /*
688  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
689  * then it is no longer reliable, so we stop using it and we mark the file
690  * as failed in the superblock
691  */
692 static void bitmap_file_kick(struct bitmap *bitmap)
693 {
694         char *path, *ptr = NULL;
695
696         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
697         bitmap_update_sb(bitmap);
698
699         if (bitmap->file) {
700                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
701                 if (path)
702                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
703
704                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
705                        bmname(bitmap), ptr ? ptr : "");
706
707                 kfree(path);
708         }
709
710         bitmap_file_put(bitmap);
711
712         return;
713 }
714
715 enum bitmap_page_attr {
716         BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
717         BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
718         BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
719 };
720
721 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
722                                 enum bitmap_page_attr attr)
723 {
724         bitmap->filemap_attr[page->index] |= attr;
725 }
726
727 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
728                                 enum bitmap_page_attr attr)
729 {
730         bitmap->filemap_attr[page->index] &= ~attr;
731 }
732
733 static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
734 {
735         return bitmap->filemap_attr[page->index];
736 }
737
738 /*
739  * bitmap_file_set_bit -- called before performing a write to the md device
740  * to set (and eventually sync) a particular bit in the bitmap file
741  *
742  * we set the bit immediately, then we record the page number so that
743  * when an unplug occurs, we can flush the dirty pages out to disk
744  */
745 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
746 {
747         unsigned long bit;
748         struct page *page;
749         void *kaddr;
750         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
751
752         if (!bitmap->filemap) {
753                 return;
754         }
755
756         page = filemap_get_page(bitmap, chunk);
757         bit = file_page_offset(chunk);
758
759
760         /* make sure the page stays cached until it gets written out */
761         if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
762                 page_cache_get(page);
763
764         /* set the bit */
765         kaddr = kmap_atomic(page, KM_USER0);
766         set_bit(bit, kaddr);
767         kunmap_atomic(kaddr, KM_USER0);
768         PRINTK("set file bit %lu page %lu\n", bit, page->index);
769
770         /* record page number so it gets flushed to disk when unplug occurs */
771         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
772
773 }
774
775 /* this gets called when the md device is ready to unplug its underlying
776  * (slave) device queues -- before we let any writes go down, we need to
777  * sync the dirty pages of the bitmap file to disk */
778 int bitmap_unplug(struct bitmap *bitmap)
779 {
780         unsigned long i, attr, flags;
781         struct page *page;
782         int wait = 0;
783         int err;
784
785         if (!bitmap)
786                 return 0;
787
788         /* look at each page to see if there are any set bits that need to be
789          * flushed out to disk */
790         for (i = 0; i < bitmap->file_pages; i++) {
791                 spin_lock_irqsave(&bitmap->lock, flags);
792                 if (!bitmap->filemap) {
793                         spin_unlock_irqrestore(&bitmap->lock, flags);
794                         return 0;
795                 }
796                 page = bitmap->filemap[i];
797                 attr = get_page_attr(bitmap, page);
798                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
799                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
800                 if ((attr & BITMAP_PAGE_DIRTY))
801                         wait = 1;
802                 spin_unlock_irqrestore(&bitmap->lock, flags);
803
804                 if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE)) {
805                         err = write_page(bitmap, page, 0);
806                         if (err == -EAGAIN) {
807                                 if (attr & BITMAP_PAGE_DIRTY)
808                                         err = write_page(bitmap, page, 1);
809                                 else
810                                         err = 0;
811                         }
812                         if (err)
813                                 return 1;
814                 }
815         }
816         if (wait) { /* if any writes were performed, we need to wait on them */
817                 if (bitmap->file) {
818                         spin_lock_irq(&bitmap->write_lock);
819                         wait_event_lock_irq(bitmap->write_wait,
820                                             list_empty(&bitmap->complete_pages), bitmap->write_lock,
821                                             wake_up_process(bitmap->writeback_daemon->tsk));
822                         spin_unlock_irq(&bitmap->write_lock);
823                 } else
824                         wait_event(bitmap->mddev->sb_wait,
825                                    atomic_read(&bitmap->mddev->pending_writes)==0);
826         }
827         return 0;
828 }
829
830 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
831 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
832  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
833  * memory mapping of the bitmap file
834  * Special cases:
835  *   if there's no bitmap file, or if the bitmap file had been
836  *   previously kicked from the array, we mark all the bits as
837  *   1's in order to cause a full resync.
838  *
839  * We ignore all bits for sectors that end earlier than 'start'.
840  * This is used when reading an out-of-date bitmap...
841  */
842 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
843 {
844         unsigned long i, chunks, index, oldindex, bit;
845         struct page *page = NULL, *oldpage = NULL;
846         unsigned long num_pages, bit_cnt = 0;
847         struct file *file;
848         unsigned long bytes, offset, dummy;
849         int outofdate;
850         int ret = -ENOSPC;
851
852         chunks = bitmap->chunks;
853         file = bitmap->file;
854
855         BUG_ON(!file && !bitmap->offset);
856
857 #ifdef INJECT_FAULTS_3
858         outofdate = 1;
859 #else
860         outofdate = bitmap->flags & BITMAP_STALE;
861 #endif
862         if (outofdate)
863                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
864                         "recovery\n", bmname(bitmap));
865
866         bytes = (chunks + 7) / 8;
867
868         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
869
870         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
871                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
872                         bmname(bitmap),
873                         (unsigned long) i_size_read(file->f_mapping->host),
874                         bytes + sizeof(bitmap_super_t));
875                 goto out;
876         }
877
878         ret = -ENOMEM;
879
880         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
881         if (!bitmap->filemap)
882                 goto out;
883
884         bitmap->filemap_attr = kmalloc(sizeof(long) * num_pages, GFP_KERNEL);
885         if (!bitmap->filemap_attr)
886                 goto out;
887
888         memset(bitmap->filemap_attr, 0, sizeof(long) * num_pages);
889
890         oldindex = ~0L;
891
892         for (i = 0; i < chunks; i++) {
893                 index = file_page_index(i);
894                 bit = file_page_offset(i);
895                 if (index != oldindex) { /* this is a new page, read it in */
896                         /* unmap the old page, we're done with it */
897                         if (oldpage != NULL)
898                                 kunmap(oldpage);
899                         if (index == 0) {
900                                 /*
901                                  * if we're here then the superblock page
902                                  * contains some bits (PAGE_SIZE != sizeof sb)
903                                  * we've already read it in, so just use it
904                                  */
905                                 page = bitmap->sb_page;
906                                 offset = sizeof(bitmap_super_t);
907                         } else if (file) {
908                                 page = read_page(file, index, &dummy);
909                                 offset = 0;
910                         } else {
911                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
912                                 offset = 0;
913                         }
914                         if (IS_ERR(page)) { /* read error */
915                                 ret = PTR_ERR(page);
916                                 goto out;
917                         }
918
919                         oldindex = index;
920                         oldpage = page;
921                         kmap(page);
922
923                         if (outofdate) {
924                                 /*
925                                  * if bitmap is out of date, dirty the
926                                  * whole page and write it out
927                                  */
928                                 memset(page_address(page) + offset, 0xff,
929                                        PAGE_SIZE - offset);
930                                 ret = write_page(bitmap, page, 1);
931                                 if (ret) {
932                                         kunmap(page);
933                                         /* release, page not in filemap yet */
934                                         page_cache_release(page);
935                                         goto out;
936                                 }
937                         }
938
939                         bitmap->filemap[bitmap->file_pages++] = page;
940                 }
941                 if (test_bit(bit, page_address(page))) {
942                         /* if the disk bit is set, set the memory bit */
943                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
944                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
945                                 );
946                         bit_cnt++;
947                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
948                 }
949         }
950
951         /* everything went OK */
952         ret = 0;
953         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
954
955         if (page) /* unmap the last page */
956                 kunmap(page);
957
958         if (bit_cnt) { /* Kick recovery if any bits were set */
959                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
960                 md_wakeup_thread(bitmap->mddev->thread);
961         }
962
963 out:
964         printk(KERN_INFO "%s: bitmap initialized from disk: "
965                 "read %lu/%lu pages, set %lu bits, status: %d\n",
966                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
967
968         return ret;
969 }
970
971 void bitmap_write_all(struct bitmap *bitmap)
972 {
973         /* We don't actually write all bitmap blocks here,
974          * just flag them as needing to be written
975          */
976
977         unsigned long chunks = bitmap->chunks;
978         unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
979         unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
980         while (num_pages--)
981                 bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
982 }
983
984
985 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
986 {
987         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
988         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
989         bitmap->bp[page].count += inc;
990 /*
991         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
992                               (unsigned long long)offset, inc, bitmap->bp[page].count);
993 */
994         bitmap_checkfree(bitmap, page);
995 }
996 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
997                                             sector_t offset, int *blocks,
998                                             int create);
999
1000 /*
1001  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1002  *                      out to disk
1003  */
1004
1005 int bitmap_daemon_work(struct bitmap *bitmap)
1006 {
1007         unsigned long j;
1008         unsigned long flags;
1009         struct page *page = NULL, *lastpage = NULL;
1010         int err = 0;
1011         int blocks;
1012         int attr;
1013
1014         if (bitmap == NULL)
1015                 return 0;
1016         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1017                 return 0;
1018         bitmap->daemon_lastrun = jiffies;
1019
1020         for (j = 0; j < bitmap->chunks; j++) {
1021                 bitmap_counter_t *bmc;
1022                 spin_lock_irqsave(&bitmap->lock, flags);
1023                 if (!bitmap->filemap) {
1024                         /* error or shutdown */
1025                         spin_unlock_irqrestore(&bitmap->lock, flags);
1026                         break;
1027                 }
1028
1029                 page = filemap_get_page(bitmap, j);
1030
1031                 if (page != lastpage) {
1032                         /* skip this page unless it's marked as needing cleaning */
1033                         if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
1034                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1035                                         page_cache_get(page);
1036                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1037                                 }
1038                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1039                                 if (attr & BITMAP_PAGE_NEEDWRITE) {
1040                                         switch (write_page(bitmap, page, 0)) {
1041                                         case -EAGAIN:
1042                                                 set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1043                                                 break;
1044                                         case 0:
1045                                                 break;
1046                                         default:
1047                                                 bitmap_file_kick(bitmap);
1048                                         }
1049                                         page_cache_release(page);
1050                                 }
1051                                 continue;
1052                         }
1053
1054                         /* grab the new page, sync and release the old */
1055                         page_cache_get(page);
1056                         if (lastpage != NULL) {
1057                                 if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
1058                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1059                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1060                                         err = write_page(bitmap, lastpage, 0);
1061                                         if (err == -EAGAIN) {
1062                                                 err = 0;
1063                                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1064                                         }
1065                                 } else {
1066                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1067                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1068                                 }
1069                                 kunmap(lastpage);
1070                                 page_cache_release(lastpage);
1071                                 if (err)
1072                                         bitmap_file_kick(bitmap);
1073                         } else
1074                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1075                         lastpage = page;
1076                         kmap(page);
1077 /*
1078                         printk("bitmap clean at page %lu\n", j);
1079 */
1080                         spin_lock_irqsave(&bitmap->lock, flags);
1081                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1082                 }
1083                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1084                                         &blocks, 0);
1085                 if (bmc) {
1086 /*
1087   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1088 */
1089                         if (*bmc == 2) {
1090                                 *bmc=1; /* maybe clear the bit next time */
1091                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1092                         } else if (*bmc == 1) {
1093                                 /* we can clear the bit */
1094                                 *bmc = 0;
1095                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1096                                                   -1);
1097
1098                                 /* clear the bit */
1099                                 clear_bit(file_page_offset(j), page_address(page));
1100                         }
1101                 }
1102                 spin_unlock_irqrestore(&bitmap->lock, flags);
1103         }
1104
1105         /* now sync the final page */
1106         if (lastpage != NULL) {
1107                 kunmap(lastpage);
1108                 spin_lock_irqsave(&bitmap->lock, flags);
1109                 if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
1110                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1111                         spin_unlock_irqrestore(&bitmap->lock, flags);
1112                         err = write_page(bitmap, lastpage, 0);
1113                         if (err == -EAGAIN) {
1114                                 set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1115                                 err = 0;
1116                         }
1117                 } else {
1118                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1119                         spin_unlock_irqrestore(&bitmap->lock, flags);
1120                 }
1121
1122                 page_cache_release(lastpage);
1123         }
1124
1125         return err;
1126 }
1127
1128 static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
1129 {
1130         mdk_thread_t *dmn;
1131         unsigned long flags;
1132
1133         /* if no one is waiting on us, we'll free the md thread struct
1134          * and exit, otherwise we let the waiter clean things up */
1135         spin_lock_irqsave(&bitmap->lock, flags);
1136         if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
1137                 *daemon = NULL;
1138                 spin_unlock_irqrestore(&bitmap->lock, flags);
1139                 kfree(dmn);
1140                 complete_and_exit(NULL, 0); /* do_exit not exported */
1141         }
1142         spin_unlock_irqrestore(&bitmap->lock, flags);
1143 }
1144
1145 static void bitmap_writeback_daemon(mddev_t *mddev)
1146 {
1147         struct bitmap *bitmap = mddev->bitmap;
1148         struct page *page;
1149         struct page_list *item;
1150         int err = 0;
1151
1152         if (signal_pending(current)) {
1153                 printk(KERN_INFO
1154                        "%s: bitmap writeback daemon got signal, exiting...\n",
1155                        bmname(bitmap));
1156                 err = -EINTR;
1157                 goto out;
1158         }
1159         if (bitmap == NULL)
1160                 /* about to be stopped. */
1161                 return;
1162
1163         PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
1164         /* wait on bitmap page writebacks */
1165         while ((item = dequeue_page(bitmap))) {
1166                 page = item->page;
1167                 mempool_free(item, bitmap->write_pool);
1168                 PRINTK("wait on page writeback: %p\n", page);
1169                 wait_on_page_writeback(page);
1170                 PRINTK("finished page writeback: %p\n", page);
1171
1172                 err = PageError(page);
1173                 page_cache_release(page);
1174                 if (err) {
1175                         printk(KERN_WARNING "%s: bitmap file writeback "
1176                                "failed (page %lu): %d\n",
1177                                bmname(bitmap), page->index, err);
1178                         bitmap_file_kick(bitmap);
1179                         goto out;
1180                 }
1181         }
1182  out:
1183         wake_up(&bitmap->write_wait);
1184         if (err) {
1185                 printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1186                        bmname(bitmap), err);
1187                 daemon_exit(bitmap, &bitmap->writeback_daemon);
1188         }
1189 }
1190
1191 static mdk_thread_t *bitmap_start_daemon(struct bitmap *bitmap,
1192                                 void (*func)(mddev_t *), char *name)
1193 {
1194         mdk_thread_t *daemon;
1195         char namebuf[32];
1196
1197 #ifdef INJECT_FATAL_FAULT_2
1198         daemon = NULL;
1199 #else
1200         sprintf(namebuf, "%%s_%s", name);
1201         daemon = md_register_thread(func, bitmap->mddev, namebuf);
1202 #endif
1203         if (!daemon) {
1204                 printk(KERN_ERR "%s: failed to start bitmap daemon\n",
1205                         bmname(bitmap));
1206                 return ERR_PTR(-ECHILD);
1207         }
1208
1209         md_wakeup_thread(daemon); /* start it running */
1210
1211         PRINTK("%s: %s daemon (pid %d) started...\n",
1212                 bmname(bitmap), name, daemon->tsk->pid);
1213
1214         return daemon;
1215 }
1216
1217 static void bitmap_stop_daemon(struct bitmap *bitmap)
1218 {
1219         /* the daemon can't stop itself... it'll just exit instead... */
1220         if (bitmap->writeback_daemon && ! IS_ERR(bitmap->writeback_daemon) &&
1221             current->pid != bitmap->writeback_daemon->tsk->pid) {
1222                 mdk_thread_t *daemon;
1223                 unsigned long flags;
1224
1225                 spin_lock_irqsave(&bitmap->lock, flags);
1226                 daemon = bitmap->writeback_daemon;
1227                 bitmap->writeback_daemon = NULL;
1228                 spin_unlock_irqrestore(&bitmap->lock, flags);
1229                 if (daemon && ! IS_ERR(daemon))
1230                         md_unregister_thread(daemon); /* destroy the thread */
1231         }
1232 }
1233
1234 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1235                                             sector_t offset, int *blocks,
1236                                             int create)
1237 {
1238         /* If 'create', we might release the lock and reclaim it.
1239          * The lock must have been taken with interrupts enabled.
1240          * If !create, we don't release the lock.
1241          */
1242         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1243         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1244         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1245         sector_t csize;
1246
1247         if (bitmap_checkpage(bitmap, page, create) < 0) {
1248                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1249                 *blocks = csize - (offset & (csize- 1));
1250                 return NULL;
1251         }
1252         /* now locked ... */
1253
1254         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1255                 /* should we use the first or second counter field
1256                  * of the hijacked pointer? */
1257                 int hi = (pageoff > PAGE_COUNTER_MASK);
1258                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1259                                           PAGE_COUNTER_SHIFT - 1);
1260                 *blocks = csize - (offset & (csize- 1));
1261                 return  &((bitmap_counter_t *)
1262                           &bitmap->bp[page].map)[hi];
1263         } else { /* page is allocated */
1264                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1265                 *blocks = csize - (offset & (csize- 1));
1266                 return (bitmap_counter_t *)
1267                         &(bitmap->bp[page].map[pageoff]);
1268         }
1269 }
1270
1271 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1272 {
1273         if (!bitmap) return 0;
1274
1275         if (behind) {
1276                 atomic_inc(&bitmap->behind_writes);
1277                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1278                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1279         }
1280
1281         while (sectors) {
1282                 int blocks;
1283                 bitmap_counter_t *bmc;
1284
1285                 spin_lock_irq(&bitmap->lock);
1286                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1287                 if (!bmc) {
1288                         spin_unlock_irq(&bitmap->lock);
1289                         return 0;
1290                 }
1291
1292                 switch(*bmc) {
1293                 case 0:
1294                         bitmap_file_set_bit(bitmap, offset);
1295                         bitmap_count_page(bitmap,offset, 1);
1296                         blk_plug_device(bitmap->mddev->queue);
1297                         /* fall through */
1298                 case 1:
1299                         *bmc = 2;
1300                 }
1301                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX) BUG();
1302                 (*bmc)++;
1303
1304                 spin_unlock_irq(&bitmap->lock);
1305
1306                 offset += blocks;
1307                 if (sectors > blocks)
1308                         sectors -= blocks;
1309                 else sectors = 0;
1310         }
1311         return 0;
1312 }
1313
1314 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1315                      int success, int behind)
1316 {
1317         if (!bitmap) return;
1318         if (behind) {
1319                 atomic_dec(&bitmap->behind_writes);
1320                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1321                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1322         }
1323
1324         while (sectors) {
1325                 int blocks;
1326                 unsigned long flags;
1327                 bitmap_counter_t *bmc;
1328
1329                 spin_lock_irqsave(&bitmap->lock, flags);
1330                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1331                 if (!bmc) {
1332                         spin_unlock_irqrestore(&bitmap->lock, flags);
1333                         return;
1334                 }
1335
1336                 if (!success && ! (*bmc & NEEDED_MASK))
1337                         *bmc |= NEEDED_MASK;
1338
1339                 (*bmc)--;
1340                 if (*bmc <= 2) {
1341                         set_page_attr(bitmap,
1342                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1343                                       BITMAP_PAGE_CLEAN);
1344                 }
1345                 spin_unlock_irqrestore(&bitmap->lock, flags);
1346                 offset += blocks;
1347                 if (sectors > blocks)
1348                         sectors -= blocks;
1349                 else sectors = 0;
1350         }
1351 }
1352
1353 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1354                         int degraded)
1355 {
1356         bitmap_counter_t *bmc;
1357         int rv;
1358         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1359                 *blocks = 1024;
1360                 return 1; /* always resync if no bitmap */
1361         }
1362         spin_lock_irq(&bitmap->lock);
1363         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1364         rv = 0;
1365         if (bmc) {
1366                 /* locked */
1367                 if (RESYNC(*bmc))
1368                         rv = 1;
1369                 else if (NEEDED(*bmc)) {
1370                         rv = 1;
1371                         if (!degraded) { /* don't set/clear bits if degraded */
1372                                 *bmc |= RESYNC_MASK;
1373                                 *bmc &= ~NEEDED_MASK;
1374                         }
1375                 }
1376         }
1377         spin_unlock_irq(&bitmap->lock);
1378         return rv;
1379 }
1380
1381 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1382 {
1383         bitmap_counter_t *bmc;
1384         unsigned long flags;
1385 /*
1386         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1387 */      if (bitmap == NULL) {
1388                 *blocks = 1024;
1389                 return;
1390         }
1391         spin_lock_irqsave(&bitmap->lock, flags);
1392         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1393         if (bmc == NULL)
1394                 goto unlock;
1395         /* locked */
1396 /*
1397         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1398 */
1399         if (RESYNC(*bmc)) {
1400                 *bmc &= ~RESYNC_MASK;
1401
1402                 if (!NEEDED(*bmc) && aborted)
1403                         *bmc |= NEEDED_MASK;
1404                 else {
1405                         if (*bmc <= 2) {
1406                                 set_page_attr(bitmap,
1407                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1408                                               BITMAP_PAGE_CLEAN);
1409                         }
1410                 }
1411         }
1412  unlock:
1413         spin_unlock_irqrestore(&bitmap->lock, flags);
1414 }
1415
1416 void bitmap_close_sync(struct bitmap *bitmap)
1417 {
1418         /* Sync has finished, and any bitmap chunks that weren't synced
1419          * properly have been aborted.  It remains to us to clear the
1420          * RESYNC bit wherever it is still on
1421          */
1422         sector_t sector = 0;
1423         int blocks;
1424         if (!bitmap) return;
1425         while (sector < bitmap->mddev->resync_max_sectors) {
1426                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1427 /*
1428                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1429                                          (unsigned long long)sector, blocks);
1430 */              sector += blocks;
1431         }
1432 }
1433
1434 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1435 {
1436         /* For each chunk covered by any of these sectors, set the
1437          * counter to 1 and set resync_needed.  They should all
1438          * be 0 at this point
1439          */
1440
1441         int secs;
1442         bitmap_counter_t *bmc;
1443         spin_lock_irq(&bitmap->lock);
1444         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1445         if (!bmc) {
1446                 spin_unlock_irq(&bitmap->lock);
1447                 return;
1448         }
1449         if (! *bmc) {
1450                 struct page *page;
1451                 *bmc = 1 | (needed?NEEDED_MASK:0);
1452                 bitmap_count_page(bitmap, offset, 1);
1453                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1454                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1455         }
1456         spin_unlock_irq(&bitmap->lock);
1457
1458 }
1459
1460 /*
1461  * flush out any pending updates
1462  */
1463 void bitmap_flush(mddev_t *mddev)
1464 {
1465         struct bitmap *bitmap = mddev->bitmap;
1466         int sleep;
1467
1468         if (!bitmap) /* there was no bitmap */
1469                 return;
1470
1471         /* run the daemon_work three time to ensure everything is flushed
1472          * that can be
1473          */
1474         sleep = bitmap->daemon_sleep;
1475         bitmap->daemon_sleep = 0;
1476         bitmap_daemon_work(bitmap);
1477         bitmap_daemon_work(bitmap);
1478         bitmap_daemon_work(bitmap);
1479         bitmap->daemon_sleep = sleep;
1480         bitmap_update_sb(bitmap);
1481 }
1482
1483 /*
1484  * free memory that was allocated
1485  */
1486 static void bitmap_free(struct bitmap *bitmap)
1487 {
1488         unsigned long k, pages;
1489         struct bitmap_page *bp;
1490
1491         if (!bitmap) /* there was no bitmap */
1492                 return;
1493
1494         /* release the bitmap file and kill the daemon */
1495         bitmap_file_put(bitmap);
1496
1497         bp = bitmap->bp;
1498         pages = bitmap->pages;
1499
1500         /* free all allocated memory */
1501
1502         mempool_destroy(bitmap->write_pool);
1503
1504         if (bp) /* deallocate the page memory */
1505                 for (k = 0; k < pages; k++)
1506                         if (bp[k].map && !bp[k].hijacked)
1507                                 kfree(bp[k].map);
1508         kfree(bp);
1509         kfree(bitmap);
1510 }
1511 void bitmap_destroy(mddev_t *mddev)
1512 {
1513         struct bitmap *bitmap = mddev->bitmap;
1514
1515         if (!bitmap) /* there was no bitmap */
1516                 return;
1517
1518         mddev->bitmap = NULL; /* disconnect from the md device */
1519
1520         bitmap_free(bitmap);
1521 }
1522
1523 /*
1524  * initialize the bitmap structure
1525  * if this returns an error, bitmap_destroy must be called to do clean up
1526  */
1527 int bitmap_create(mddev_t *mddev)
1528 {
1529         struct bitmap *bitmap;
1530         unsigned long blocks = mddev->resync_max_sectors;
1531         unsigned long chunks;
1532         unsigned long pages;
1533         struct file *file = mddev->bitmap_file;
1534         int err;
1535         sector_t start;
1536
1537         BUG_ON(sizeof(bitmap_super_t) != 256);
1538
1539         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1540                 return 0;
1541
1542         BUG_ON(file && mddev->bitmap_offset);
1543
1544         bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
1545         if (!bitmap)
1546                 return -ENOMEM;
1547
1548         memset(bitmap, 0, sizeof(*bitmap));
1549
1550         spin_lock_init(&bitmap->lock);
1551         bitmap->mddev = mddev;
1552
1553         spin_lock_init(&bitmap->write_lock);
1554         INIT_LIST_HEAD(&bitmap->complete_pages);
1555         init_waitqueue_head(&bitmap->write_wait);
1556         bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
1557                                 write_pool_free, NULL);
1558         err = -ENOMEM;
1559         if (!bitmap->write_pool)
1560                 goto error;
1561
1562         bitmap->file = file;
1563         bitmap->offset = mddev->bitmap_offset;
1564         if (file) get_file(file);
1565         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1566         err = bitmap_read_sb(bitmap);
1567         if (err)
1568                 goto error;
1569
1570         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1571                                         sizeof(bitmap->chunksize));
1572
1573         /* now that chunksize and chunkshift are set, we can use these macros */
1574         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1575                         CHUNK_BLOCK_RATIO(bitmap);
1576         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1577
1578         BUG_ON(!pages);
1579
1580         bitmap->chunks = chunks;
1581         bitmap->pages = pages;
1582         bitmap->missing_pages = pages;
1583         bitmap->counter_bits = COUNTER_BITS;
1584
1585         bitmap->syncchunk = ~0UL;
1586
1587 #ifdef INJECT_FATAL_FAULT_1
1588         bitmap->bp = NULL;
1589 #else
1590         bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1591 #endif
1592         err = -ENOMEM;
1593         if (!bitmap->bp)
1594                 goto error;
1595         memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));
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         return bitmap_update_sb(bitmap);
1626
1627  error:
1628         bitmap_free(bitmap);
1629         return err;
1630 }
1631
1632 /* the bitmap API -- for raid personalities */
1633 EXPORT_SYMBOL(bitmap_startwrite);
1634 EXPORT_SYMBOL(bitmap_endwrite);
1635 EXPORT_SYMBOL(bitmap_start_sync);
1636 EXPORT_SYMBOL(bitmap_end_sync);
1637 EXPORT_SYMBOL(bitmap_unplug);
1638 EXPORT_SYMBOL(bitmap_close_sync);
1639 EXPORT_SYMBOL(bitmap_daemon_work);