md: change ITERATE_RDEV to rdev_for_each
[linux-2.6.git] / drivers / md / bitmap.c
1 /*
2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
3  *
4  * bitmap_create  - sets up the bitmap structure
5  * bitmap_destroy - destroys the bitmap structure
6  *
7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
8  * - added disk storage for bitmap
9  * - changes to allow various bitmap chunk sizes
10  */
11
12 /*
13  * Still to do:
14  *
15  * flush after percent set rather than just time based. (maybe both).
16  * wait if count gets too high, wake when it drops to half.
17  */
18
19 #include <linux/module.h>
20 #include <linux/errno.h>
21 #include <linux/slab.h>
22 #include <linux/init.h>
23 #include <linux/timer.h>
24 #include <linux/sched.h>
25 #include <linux/list.h>
26 #include <linux/file.h>
27 #include <linux/mount.h>
28 #include <linux/buffer_head.h>
29 #include <linux/raid/md.h>
30 #include <linux/raid/bitmap.h>
31
32 /* debug macros */
33
34 #define DEBUG 0
35
36 #if DEBUG
37 /* these are for debugging purposes only! */
38
39 /* define one and only one of these */
40 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
41 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
42 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
43 #define INJECT_FAULTS_4 0 /* undef */
44 #define INJECT_FAULTS_5 0 /* undef */
45 #define INJECT_FAULTS_6 0
46
47 /* if these are defined, the driver will fail! debug only */
48 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
49 #define INJECT_FATAL_FAULT_2 0 /* undef */
50 #define INJECT_FATAL_FAULT_3 0 /* undef */
51 #endif
52
53 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
54 #define DPRINTK(x...) do { } while(0)
55
56 #ifndef PRINTK
57 #  if DEBUG > 0
58 #    define PRINTK(x...) printk(KERN_DEBUG x)
59 #  else
60 #    define PRINTK(x...)
61 #  endif
62 #endif
63
64 static inline char * bmname(struct bitmap *bitmap)
65 {
66         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
67 }
68
69
70 /*
71  * just a placeholder - calls kmalloc for bitmap pages
72  */
73 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
74 {
75         unsigned char *page;
76
77 #ifdef INJECT_FAULTS_1
78         page = NULL;
79 #else
80         page = kmalloc(PAGE_SIZE, GFP_NOIO);
81 #endif
82         if (!page)
83                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
84         else
85                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
86                         bmname(bitmap), page);
87         return page;
88 }
89
90 /*
91  * for now just a placeholder -- just calls kfree for bitmap pages
92  */
93 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
94 {
95         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
96         kfree(page);
97 }
98
99 /*
100  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
101  *
102  * 1) check to see if this page is allocated, if it's not then try to alloc
103  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
104  *    page pointer directly as a counter
105  *
106  * if we find our page, we increment the page's refcount so that it stays
107  * allocated while we're using it
108  */
109 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
110 {
111         unsigned char *mappage;
112
113         if (page >= bitmap->pages) {
114                 printk(KERN_ALERT
115                         "%s: invalid bitmap page request: %lu (> %lu)\n",
116                         bmname(bitmap), page, bitmap->pages-1);
117                 return -EINVAL;
118         }
119
120
121         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
122                 return 0;
123
124         if (bitmap->bp[page].map) /* page is already allocated, just return */
125                 return 0;
126
127         if (!create)
128                 return -ENOENT;
129
130         spin_unlock_irq(&bitmap->lock);
131
132         /* this page has not been allocated yet */
133
134         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
135                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
136                         bmname(bitmap));
137                 /* failed - set the hijacked flag so that we can use the
138                  * pointer as a counter */
139                 spin_lock_irq(&bitmap->lock);
140                 if (!bitmap->bp[page].map)
141                         bitmap->bp[page].hijacked = 1;
142                 goto out;
143         }
144
145         /* got a page */
146
147         spin_lock_irq(&bitmap->lock);
148
149         /* recheck the page */
150
151         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
152                 /* somebody beat us to getting the page */
153                 bitmap_free_page(bitmap, mappage);
154                 return 0;
155         }
156
157         /* no page was in place and we have one, so install it */
158
159         memset(mappage, 0, PAGE_SIZE);
160         bitmap->bp[page].map = mappage;
161         bitmap->missing_pages--;
162 out:
163         return 0;
164 }
165
166
167 /* if page is completely empty, put it back on the free list, or dealloc it */
168 /* if page was hijacked, unmark the flag so it might get alloced next time */
169 /* Note: lock should be held when calling this */
170 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
171 {
172         char *ptr;
173
174         if (bitmap->bp[page].count) /* page is still busy */
175                 return;
176
177         /* page is no longer in use, it can be released */
178
179         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
180                 bitmap->bp[page].hijacked = 0;
181                 bitmap->bp[page].map = NULL;
182                 return;
183         }
184
185         /* normal case, free the page */
186
187 #if 0
188 /* actually ... let's not.  We will probably need the page again exactly when
189  * memory is tight and we are flusing to disk
190  */
191         return;
192 #else
193         ptr = bitmap->bp[page].map;
194         bitmap->bp[page].map = NULL;
195         bitmap->missing_pages++;
196         bitmap_free_page(bitmap, ptr);
197         return;
198 #endif
199 }
200
201
202 /*
203  * bitmap file handling - read and write the bitmap file and its superblock
204  */
205
206 /* copy the pathname of a file to a buffer */
207 char *file_path(struct file *file, char *buf, int count)
208 {
209         struct dentry *d;
210         struct vfsmount *v;
211
212         if (!buf)
213                 return NULL;
214
215         d = file->f_path.dentry;
216         v = file->f_path.mnt;
217
218         buf = d_path(d, v, buf, count);
219
220         return IS_ERR(buf) ? NULL : buf;
221 }
222
223 /*
224  * basic page I/O operations
225  */
226
227 /* IO operations when bitmap is stored near all superblocks */
228 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
229 {
230         /* choose a good rdev and read the page from there */
231
232         mdk_rdev_t *rdev;
233         struct list_head *tmp;
234         struct page *page = alloc_page(GFP_KERNEL);
235         sector_t target;
236
237         if (!page)
238                 return ERR_PTR(-ENOMEM);
239
240         rdev_for_each(rdev, tmp, mddev) {
241                 if (! test_bit(In_sync, &rdev->flags)
242                     || test_bit(Faulty, &rdev->flags))
243                         continue;
244
245                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
246
247                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
248                         page->index = index;
249                         attach_page_buffers(page, NULL); /* so that free_buffer will
250                                                           * quietly no-op */
251                         return page;
252                 }
253         }
254         return ERR_PTR(-EIO);
255
256 }
257
258 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
259 {
260         mdk_rdev_t *rdev;
261         struct list_head *tmp;
262         mddev_t *mddev = bitmap->mddev;
263
264         rdev_for_each(rdev, tmp, mddev)
265                 if (test_bit(In_sync, &rdev->flags)
266                     && !test_bit(Faulty, &rdev->flags)) {
267                         int size = PAGE_SIZE;
268                         if (page->index == bitmap->file_pages-1)
269                                 size = roundup(bitmap->last_page_size,
270                                                bdev_hardsect_size(rdev->bdev));
271                         /* Just make sure we aren't corrupting data or
272                          * metadata
273                          */
274                         if (bitmap->offset < 0) {
275                                 /* DATA  BITMAP METADATA  */
276                                 if (bitmap->offset
277                                     + (long)(page->index * (PAGE_SIZE/512))
278                                     + size/512 > 0)
279                                         /* bitmap runs in to metadata */
280                                         return -EINVAL;
281                                 if (rdev->data_offset + mddev->size*2
282                                     > rdev->sb_offset*2 + bitmap->offset)
283                                         /* data runs in to bitmap */
284                                         return -EINVAL;
285                         } else if (rdev->sb_offset*2 < rdev->data_offset) {
286                                 /* METADATA BITMAP DATA */
287                                 if (rdev->sb_offset*2
288                                     + bitmap->offset
289                                     + page->index*(PAGE_SIZE/512) + size/512
290                                     > rdev->data_offset)
291                                         /* bitmap runs in to data */
292                                         return -EINVAL;
293                         } else {
294                                 /* DATA METADATA BITMAP - no problems */
295                         }
296                         md_super_write(mddev, rdev,
297                                        (rdev->sb_offset<<1) + bitmap->offset
298                                        + page->index * (PAGE_SIZE/512),
299                                        size,
300                                        page);
301                 }
302
303         if (wait)
304                 md_super_wait(mddev);
305         return 0;
306 }
307
308 static void bitmap_file_kick(struct bitmap *bitmap);
309 /*
310  * write out a page to a file
311  */
312 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
313 {
314         struct buffer_head *bh;
315
316         if (bitmap->file == NULL) {
317                 switch (write_sb_page(bitmap, page, wait)) {
318                 case -EINVAL:
319                         bitmap->flags |= BITMAP_WRITE_ERROR;
320                 }
321         } else {
322
323                 bh = page_buffers(page);
324
325                 while (bh && bh->b_blocknr) {
326                         atomic_inc(&bitmap->pending_writes);
327                         set_buffer_locked(bh);
328                         set_buffer_mapped(bh);
329                         submit_bh(WRITE, bh);
330                         bh = bh->b_this_page;
331                 }
332
333                 if (wait) {
334                         wait_event(bitmap->write_wait,
335                                    atomic_read(&bitmap->pending_writes)==0);
336                 }
337         }
338         if (bitmap->flags & BITMAP_WRITE_ERROR)
339                 bitmap_file_kick(bitmap);
340 }
341
342 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
343 {
344         struct bitmap *bitmap = bh->b_private;
345         unsigned long flags;
346
347         if (!uptodate) {
348                 spin_lock_irqsave(&bitmap->lock, flags);
349                 bitmap->flags |= BITMAP_WRITE_ERROR;
350                 spin_unlock_irqrestore(&bitmap->lock, flags);
351         }
352         if (atomic_dec_and_test(&bitmap->pending_writes))
353                 wake_up(&bitmap->write_wait);
354 }
355
356 /* copied from buffer.c */
357 static void
358 __clear_page_buffers(struct page *page)
359 {
360         ClearPagePrivate(page);
361         set_page_private(page, 0);
362         page_cache_release(page);
363 }
364 static void free_buffers(struct page *page)
365 {
366         struct buffer_head *bh = page_buffers(page);
367
368         while (bh) {
369                 struct buffer_head *next = bh->b_this_page;
370                 free_buffer_head(bh);
371                 bh = next;
372         }
373         __clear_page_buffers(page);
374         put_page(page);
375 }
376
377 /* read a page from a file.
378  * We both read the page, and attach buffers to the page to record the
379  * address of each block (using bmap).  These addresses will be used
380  * to write the block later, completely bypassing the filesystem.
381  * This usage is similar to how swap files are handled, and allows us
382  * to write to a file with no concerns of memory allocation failing.
383  */
384 static struct page *read_page(struct file *file, unsigned long index,
385                               struct bitmap *bitmap,
386                               unsigned long count)
387 {
388         struct page *page = NULL;
389         struct inode *inode = file->f_path.dentry->d_inode;
390         struct buffer_head *bh;
391         sector_t block;
392
393         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
394                         (unsigned long long)index << PAGE_SHIFT);
395
396         page = alloc_page(GFP_KERNEL);
397         if (!page)
398                 page = ERR_PTR(-ENOMEM);
399         if (IS_ERR(page))
400                 goto out;
401
402         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
403         if (!bh) {
404                 put_page(page);
405                 page = ERR_PTR(-ENOMEM);
406                 goto out;
407         }
408         attach_page_buffers(page, bh);
409         block = index << (PAGE_SHIFT - inode->i_blkbits);
410         while (bh) {
411                 if (count == 0)
412                         bh->b_blocknr = 0;
413                 else {
414                         bh->b_blocknr = bmap(inode, block);
415                         if (bh->b_blocknr == 0) {
416                                 /* Cannot use this file! */
417                                 free_buffers(page);
418                                 page = ERR_PTR(-EINVAL);
419                                 goto out;
420                         }
421                         bh->b_bdev = inode->i_sb->s_bdev;
422                         if (count < (1<<inode->i_blkbits))
423                                 count = 0;
424                         else
425                                 count -= (1<<inode->i_blkbits);
426
427                         bh->b_end_io = end_bitmap_write;
428                         bh->b_private = bitmap;
429                         atomic_inc(&bitmap->pending_writes);
430                         set_buffer_locked(bh);
431                         set_buffer_mapped(bh);
432                         submit_bh(READ, bh);
433                 }
434                 block++;
435                 bh = bh->b_this_page;
436         }
437         page->index = index;
438
439         wait_event(bitmap->write_wait,
440                    atomic_read(&bitmap->pending_writes)==0);
441         if (bitmap->flags & BITMAP_WRITE_ERROR) {
442                 free_buffers(page);
443                 page = ERR_PTR(-EIO);
444         }
445 out:
446         if (IS_ERR(page))
447                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
448                         (int)PAGE_SIZE,
449                         (unsigned long long)index << PAGE_SHIFT,
450                         PTR_ERR(page));
451         return page;
452 }
453
454 /*
455  * bitmap file superblock operations
456  */
457
458 /* update the event counter and sync the superblock to disk */
459 void bitmap_update_sb(struct bitmap *bitmap)
460 {
461         bitmap_super_t *sb;
462         unsigned long flags;
463
464         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
465                 return;
466         spin_lock_irqsave(&bitmap->lock, flags);
467         if (!bitmap->sb_page) { /* no superblock */
468                 spin_unlock_irqrestore(&bitmap->lock, flags);
469                 return;
470         }
471         spin_unlock_irqrestore(&bitmap->lock, flags);
472         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
473         sb->events = cpu_to_le64(bitmap->mddev->events);
474         if (!bitmap->mddev->degraded)
475                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
476         kunmap_atomic(sb, KM_USER0);
477         write_page(bitmap, bitmap->sb_page, 1);
478 }
479
480 /* print out the bitmap file superblock */
481 void bitmap_print_sb(struct bitmap *bitmap)
482 {
483         bitmap_super_t *sb;
484
485         if (!bitmap || !bitmap->sb_page)
486                 return;
487         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
488         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
489         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
490         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
491         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
492                                         *(__u32 *)(sb->uuid+0),
493                                         *(__u32 *)(sb->uuid+4),
494                                         *(__u32 *)(sb->uuid+8),
495                                         *(__u32 *)(sb->uuid+12));
496         printk(KERN_DEBUG "        events: %llu\n",
497                         (unsigned long long) le64_to_cpu(sb->events));
498         printk(KERN_DEBUG "events cleared: %llu\n",
499                         (unsigned long long) le64_to_cpu(sb->events_cleared));
500         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
501         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
502         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
503         printk(KERN_DEBUG "     sync size: %llu KB\n",
504                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
505         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
506         kunmap_atomic(sb, KM_USER0);
507 }
508
509 /* read the superblock from the bitmap file and initialize some bitmap fields */
510 static int bitmap_read_sb(struct bitmap *bitmap)
511 {
512         char *reason = NULL;
513         bitmap_super_t *sb;
514         unsigned long chunksize, daemon_sleep, write_behind;
515         unsigned long long events;
516         int err = -EINVAL;
517
518         /* page 0 is the superblock, read it... */
519         if (bitmap->file) {
520                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
521                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
522
523                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
524         } else {
525                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
526         }
527         if (IS_ERR(bitmap->sb_page)) {
528                 err = PTR_ERR(bitmap->sb_page);
529                 bitmap->sb_page = NULL;
530                 return err;
531         }
532
533         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
534
535         chunksize = le32_to_cpu(sb->chunksize);
536         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
537         write_behind = le32_to_cpu(sb->write_behind);
538
539         /* verify that the bitmap-specific fields are valid */
540         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
541                 reason = "bad magic";
542         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
543                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
544                 reason = "unrecognized superblock version";
545         else if (chunksize < PAGE_SIZE)
546                 reason = "bitmap chunksize too small";
547         else if ((1 << ffz(~chunksize)) != chunksize)
548                 reason = "bitmap chunksize not a power of 2";
549         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
550                 reason = "daemon sleep period out of range";
551         else if (write_behind > COUNTER_MAX)
552                 reason = "write-behind limit out of range (0 - 16383)";
553         if (reason) {
554                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
555                         bmname(bitmap), reason);
556                 goto out;
557         }
558
559         /* keep the array size field of the bitmap superblock up to date */
560         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
561
562         if (!bitmap->mddev->persistent)
563                 goto success;
564
565         /*
566          * if we have a persistent array superblock, compare the
567          * bitmap's UUID and event counter to the mddev's
568          */
569         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
570                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
571                         bmname(bitmap));
572                 goto out;
573         }
574         events = le64_to_cpu(sb->events);
575         if (events < bitmap->mddev->events) {
576                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
577                         "-- forcing full recovery\n", bmname(bitmap), events,
578                         (unsigned long long) bitmap->mddev->events);
579                 sb->state |= cpu_to_le32(BITMAP_STALE);
580         }
581 success:
582         /* assign fields using values from superblock */
583         bitmap->chunksize = chunksize;
584         bitmap->daemon_sleep = daemon_sleep;
585         bitmap->daemon_lastrun = jiffies;
586         bitmap->max_write_behind = write_behind;
587         bitmap->flags |= le32_to_cpu(sb->state);
588         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
589                 bitmap->flags |= BITMAP_HOSTENDIAN;
590         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
591         if (sb->state & cpu_to_le32(BITMAP_STALE))
592                 bitmap->events_cleared = bitmap->mddev->events;
593         err = 0;
594 out:
595         kunmap_atomic(sb, KM_USER0);
596         if (err)
597                 bitmap_print_sb(bitmap);
598         return err;
599 }
600
601 enum bitmap_mask_op {
602         MASK_SET,
603         MASK_UNSET
604 };
605
606 /* record the state of the bitmap in the superblock.  Return the old value */
607 static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
608                              enum bitmap_mask_op op)
609 {
610         bitmap_super_t *sb;
611         unsigned long flags;
612         int old;
613
614         spin_lock_irqsave(&bitmap->lock, flags);
615         if (!bitmap->sb_page) { /* can't set the state */
616                 spin_unlock_irqrestore(&bitmap->lock, flags);
617                 return 0;
618         }
619         spin_unlock_irqrestore(&bitmap->lock, flags);
620         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
621         old = le32_to_cpu(sb->state) & bits;
622         switch (op) {
623                 case MASK_SET: sb->state |= cpu_to_le32(bits);
624                                 break;
625                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
626                                 break;
627                 default: BUG();
628         }
629         kunmap_atomic(sb, KM_USER0);
630         return old;
631 }
632
633 /*
634  * general bitmap file operations
635  */
636
637 /* calculate the index of the page that contains this bit */
638 static inline unsigned long file_page_index(unsigned long chunk)
639 {
640         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
641 }
642
643 /* calculate the (bit) offset of this bit within a page */
644 static inline unsigned long file_page_offset(unsigned long chunk)
645 {
646         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
647 }
648
649 /*
650  * return a pointer to the page in the filemap that contains the given bit
651  *
652  * this lookup is complicated by the fact that the bitmap sb might be exactly
653  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
654  * 0 or page 1
655  */
656 static inline struct page *filemap_get_page(struct bitmap *bitmap,
657                                         unsigned long chunk)
658 {
659         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
660         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
661 }
662
663
664 static void bitmap_file_unmap(struct bitmap *bitmap)
665 {
666         struct page **map, *sb_page;
667         unsigned long *attr;
668         int pages;
669         unsigned long flags;
670
671         spin_lock_irqsave(&bitmap->lock, flags);
672         map = bitmap->filemap;
673         bitmap->filemap = NULL;
674         attr = bitmap->filemap_attr;
675         bitmap->filemap_attr = NULL;
676         pages = bitmap->file_pages;
677         bitmap->file_pages = 0;
678         sb_page = bitmap->sb_page;
679         bitmap->sb_page = NULL;
680         spin_unlock_irqrestore(&bitmap->lock, flags);
681
682         while (pages--)
683                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
684                         free_buffers(map[pages]);
685         kfree(map);
686         kfree(attr);
687
688         if (sb_page)
689                 free_buffers(sb_page);
690 }
691
692 static void bitmap_file_put(struct bitmap *bitmap)
693 {
694         struct file *file;
695         unsigned long flags;
696
697         spin_lock_irqsave(&bitmap->lock, flags);
698         file = bitmap->file;
699         bitmap->file = NULL;
700         spin_unlock_irqrestore(&bitmap->lock, flags);
701
702         if (file)
703                 wait_event(bitmap->write_wait,
704                            atomic_read(&bitmap->pending_writes)==0);
705         bitmap_file_unmap(bitmap);
706
707         if (file) {
708                 struct inode *inode = file->f_path.dentry->d_inode;
709                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
710                 fput(file);
711         }
712 }
713
714
715 /*
716  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
717  * then it is no longer reliable, so we stop using it and we mark the file
718  * as failed in the superblock
719  */
720 static void bitmap_file_kick(struct bitmap *bitmap)
721 {
722         char *path, *ptr = NULL;
723
724         if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
725                 bitmap_update_sb(bitmap);
726
727                 if (bitmap->file) {
728                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
729                         if (path)
730                                 ptr = file_path(bitmap->file, path, PAGE_SIZE);
731
732                         printk(KERN_ALERT
733                               "%s: kicking failed bitmap file %s from array!\n",
734                               bmname(bitmap), ptr ? ptr : "");
735
736                         kfree(path);
737                 } else
738                         printk(KERN_ALERT
739                                "%s: disabling internal bitmap due to errors\n",
740                                bmname(bitmap));
741         }
742
743         bitmap_file_put(bitmap);
744
745         return;
746 }
747
748 enum bitmap_page_attr {
749         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
750         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
751         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
752 };
753
754 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
755                                 enum bitmap_page_attr attr)
756 {
757         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
758 }
759
760 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
761                                 enum bitmap_page_attr attr)
762 {
763         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
764 }
765
766 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
767                                            enum bitmap_page_attr attr)
768 {
769         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
770 }
771
772 /*
773  * bitmap_file_set_bit -- called before performing a write to the md device
774  * to set (and eventually sync) a particular bit in the bitmap file
775  *
776  * we set the bit immediately, then we record the page number so that
777  * when an unplug occurs, we can flush the dirty pages out to disk
778  */
779 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
780 {
781         unsigned long bit;
782         struct page *page;
783         void *kaddr;
784         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
785
786         if (!bitmap->filemap) {
787                 return;
788         }
789
790         page = filemap_get_page(bitmap, chunk);
791         if (!page) return;
792         bit = file_page_offset(chunk);
793
794         /* set the bit */
795         kaddr = kmap_atomic(page, KM_USER0);
796         if (bitmap->flags & BITMAP_HOSTENDIAN)
797                 set_bit(bit, kaddr);
798         else
799                 ext2_set_bit(bit, kaddr);
800         kunmap_atomic(kaddr, KM_USER0);
801         PRINTK("set file bit %lu page %lu\n", bit, page->index);
802
803         /* record page number so it gets flushed to disk when unplug occurs */
804         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
805
806 }
807
808 /* this gets called when the md device is ready to unplug its underlying
809  * (slave) device queues -- before we let any writes go down, we need to
810  * sync the dirty pages of the bitmap file to disk */
811 void bitmap_unplug(struct bitmap *bitmap)
812 {
813         unsigned long i, flags;
814         int dirty, need_write;
815         struct page *page;
816         int wait = 0;
817
818         if (!bitmap)
819                 return;
820
821         /* look at each page to see if there are any set bits that need to be
822          * flushed out to disk */
823         for (i = 0; i < bitmap->file_pages; i++) {
824                 spin_lock_irqsave(&bitmap->lock, flags);
825                 if (!bitmap->filemap) {
826                         spin_unlock_irqrestore(&bitmap->lock, flags);
827                         return;
828                 }
829                 page = bitmap->filemap[i];
830                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
831                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
832                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
833                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
834                 if (dirty)
835                         wait = 1;
836                 spin_unlock_irqrestore(&bitmap->lock, flags);
837
838                 if (dirty | need_write)
839                         write_page(bitmap, page, 0);
840         }
841         if (wait) { /* if any writes were performed, we need to wait on them */
842                 if (bitmap->file)
843                         wait_event(bitmap->write_wait,
844                                    atomic_read(&bitmap->pending_writes)==0);
845                 else
846                         md_super_wait(bitmap->mddev);
847         }
848         if (bitmap->flags & BITMAP_WRITE_ERROR)
849                 bitmap_file_kick(bitmap);
850 }
851
852 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
853 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
854  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
855  * memory mapping of the bitmap file
856  * Special cases:
857  *   if there's no bitmap file, or if the bitmap file had been
858  *   previously kicked from the array, we mark all the bits as
859  *   1's in order to cause a full resync.
860  *
861  * We ignore all bits for sectors that end earlier than 'start'.
862  * This is used when reading an out-of-date bitmap...
863  */
864 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
865 {
866         unsigned long i, chunks, index, oldindex, bit;
867         struct page *page = NULL, *oldpage = NULL;
868         unsigned long num_pages, bit_cnt = 0;
869         struct file *file;
870         unsigned long bytes, offset;
871         int outofdate;
872         int ret = -ENOSPC;
873         void *paddr;
874
875         chunks = bitmap->chunks;
876         file = bitmap->file;
877
878         BUG_ON(!file && !bitmap->offset);
879
880 #ifdef INJECT_FAULTS_3
881         outofdate = 1;
882 #else
883         outofdate = bitmap->flags & BITMAP_STALE;
884 #endif
885         if (outofdate)
886                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
887                         "recovery\n", bmname(bitmap));
888
889         bytes = (chunks + 7) / 8;
890
891         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
892
893         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
894                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
895                         bmname(bitmap),
896                         (unsigned long) i_size_read(file->f_mapping->host),
897                         bytes + sizeof(bitmap_super_t));
898                 goto err;
899         }
900
901         ret = -ENOMEM;
902
903         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
904         if (!bitmap->filemap)
905                 goto err;
906
907         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
908         bitmap->filemap_attr = kzalloc(
909                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
910                 GFP_KERNEL);
911         if (!bitmap->filemap_attr)
912                 goto err;
913
914         oldindex = ~0L;
915
916         for (i = 0; i < chunks; i++) {
917                 int b;
918                 index = file_page_index(i);
919                 bit = file_page_offset(i);
920                 if (index != oldindex) { /* this is a new page, read it in */
921                         int count;
922                         /* unmap the old page, we're done with it */
923                         if (index == num_pages-1)
924                                 count = bytes + sizeof(bitmap_super_t)
925                                         - index * PAGE_SIZE;
926                         else
927                                 count = PAGE_SIZE;
928                         if (index == 0) {
929                                 /*
930                                  * if we're here then the superblock page
931                                  * contains some bits (PAGE_SIZE != sizeof sb)
932                                  * we've already read it in, so just use it
933                                  */
934                                 page = bitmap->sb_page;
935                                 offset = sizeof(bitmap_super_t);
936                         } else if (file) {
937                                 page = read_page(file, index, bitmap, count);
938                                 offset = 0;
939                         } else {
940                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
941                                 offset = 0;
942                         }
943                         if (IS_ERR(page)) { /* read error */
944                                 ret = PTR_ERR(page);
945                                 goto err;
946                         }
947
948                         oldindex = index;
949                         oldpage = page;
950
951                         if (outofdate) {
952                                 /*
953                                  * if bitmap is out of date, dirty the
954                                  * whole page and write it out
955                                  */
956                                 paddr = kmap_atomic(page, KM_USER0);
957                                 memset(paddr + offset, 0xff,
958                                        PAGE_SIZE - offset);
959                                 kunmap_atomic(paddr, KM_USER0);
960                                 write_page(bitmap, page, 1);
961
962                                 ret = -EIO;
963                                 if (bitmap->flags & BITMAP_WRITE_ERROR) {
964                                         /* release, page not in filemap yet */
965                                         put_page(page);
966                                         goto err;
967                                 }
968                         }
969
970                         bitmap->filemap[bitmap->file_pages++] = page;
971                         bitmap->last_page_size = count;
972                 }
973                 paddr = kmap_atomic(page, KM_USER0);
974                 if (bitmap->flags & BITMAP_HOSTENDIAN)
975                         b = test_bit(bit, paddr);
976                 else
977                         b = ext2_test_bit(bit, paddr);
978                 kunmap_atomic(paddr, KM_USER0);
979                 if (b) {
980                         /* if the disk bit is set, set the memory bit */
981                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
982                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
983                                 );
984                         bit_cnt++;
985                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
986                 }
987         }
988
989         /* everything went OK */
990         ret = 0;
991         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
992
993         if (bit_cnt) { /* Kick recovery if any bits were set */
994                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
995                 md_wakeup_thread(bitmap->mddev->thread);
996         }
997
998         printk(KERN_INFO "%s: bitmap initialized from disk: "
999                 "read %lu/%lu pages, set %lu bits\n",
1000                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
1001
1002         return 0;
1003
1004  err:
1005         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1006                bmname(bitmap), ret);
1007         return ret;
1008 }
1009
1010 void bitmap_write_all(struct bitmap *bitmap)
1011 {
1012         /* We don't actually write all bitmap blocks here,
1013          * just flag them as needing to be written
1014          */
1015         int i;
1016
1017         for (i=0; i < bitmap->file_pages; i++)
1018                 set_page_attr(bitmap, bitmap->filemap[i],
1019                               BITMAP_PAGE_NEEDWRITE);
1020 }
1021
1022
1023 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
1024 {
1025         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1026         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1027         bitmap->bp[page].count += inc;
1028 /*
1029         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
1030                               (unsigned long long)offset, inc, bitmap->bp[page].count);
1031 */
1032         bitmap_checkfree(bitmap, page);
1033 }
1034 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1035                                             sector_t offset, int *blocks,
1036                                             int create);
1037
1038 /*
1039  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1040  *                      out to disk
1041  */
1042
1043 void bitmap_daemon_work(struct bitmap *bitmap)
1044 {
1045         unsigned long j;
1046         unsigned long flags;
1047         struct page *page = NULL, *lastpage = NULL;
1048         int blocks;
1049         void *paddr;
1050
1051         if (bitmap == NULL)
1052                 return;
1053         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1054                 return;
1055         bitmap->daemon_lastrun = jiffies;
1056
1057         for (j = 0; j < bitmap->chunks; j++) {
1058                 bitmap_counter_t *bmc;
1059                 spin_lock_irqsave(&bitmap->lock, flags);
1060                 if (!bitmap->filemap) {
1061                         /* error or shutdown */
1062                         spin_unlock_irqrestore(&bitmap->lock, flags);
1063                         break;
1064                 }
1065
1066                 page = filemap_get_page(bitmap, j);
1067
1068                 if (page != lastpage) {
1069                         /* skip this page unless it's marked as needing cleaning */
1070                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1071                                 int need_write = test_page_attr(bitmap, page,
1072                                                                 BITMAP_PAGE_NEEDWRITE);
1073                                 if (need_write)
1074                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1075
1076                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1077                                 if (need_write)
1078                                         write_page(bitmap, page, 0);
1079                                 continue;
1080                         }
1081
1082                         /* grab the new page, sync and release the old */
1083                         if (lastpage != NULL) {
1084                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1085                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1086                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1087                                         write_page(bitmap, lastpage, 0);
1088                                 } else {
1089                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1090                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1091                                 }
1092                         } else
1093                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1094                         lastpage = page;
1095 /*
1096                         printk("bitmap clean at page %lu\n", j);
1097 */
1098                         spin_lock_irqsave(&bitmap->lock, flags);
1099                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1100                 }
1101                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1102                                         &blocks, 0);
1103                 if (bmc) {
1104 /*
1105   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1106 */
1107                         if (*bmc == 2) {
1108                                 *bmc=1; /* maybe clear the bit next time */
1109                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1110                         } else if (*bmc == 1) {
1111                                 /* we can clear the bit */
1112                                 *bmc = 0;
1113                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1114                                                   -1);
1115
1116                                 /* clear the bit */
1117                                 paddr = kmap_atomic(page, KM_USER0);
1118                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1119                                         clear_bit(file_page_offset(j), paddr);
1120                                 else
1121                                         ext2_clear_bit(file_page_offset(j), paddr);
1122                                 kunmap_atomic(paddr, KM_USER0);
1123                         }
1124                 }
1125                 spin_unlock_irqrestore(&bitmap->lock, flags);
1126         }
1127
1128         /* now sync the final page */
1129         if (lastpage != NULL) {
1130                 spin_lock_irqsave(&bitmap->lock, flags);
1131                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1132                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1133                         spin_unlock_irqrestore(&bitmap->lock, flags);
1134                         write_page(bitmap, lastpage, 0);
1135                 } else {
1136                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1137                         spin_unlock_irqrestore(&bitmap->lock, flags);
1138                 }
1139         }
1140
1141 }
1142
1143 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1144                                             sector_t offset, int *blocks,
1145                                             int create)
1146 {
1147         /* If 'create', we might release the lock and reclaim it.
1148          * The lock must have been taken with interrupts enabled.
1149          * If !create, we don't release the lock.
1150          */
1151         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1152         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1153         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1154         sector_t csize;
1155
1156         if (bitmap_checkpage(bitmap, page, create) < 0) {
1157                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1158                 *blocks = csize - (offset & (csize- 1));
1159                 return NULL;
1160         }
1161         /* now locked ... */
1162
1163         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1164                 /* should we use the first or second counter field
1165                  * of the hijacked pointer? */
1166                 int hi = (pageoff > PAGE_COUNTER_MASK);
1167                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1168                                           PAGE_COUNTER_SHIFT - 1);
1169                 *blocks = csize - (offset & (csize- 1));
1170                 return  &((bitmap_counter_t *)
1171                           &bitmap->bp[page].map)[hi];
1172         } else { /* page is allocated */
1173                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1174                 *blocks = csize - (offset & (csize- 1));
1175                 return (bitmap_counter_t *)
1176                         &(bitmap->bp[page].map[pageoff]);
1177         }
1178 }
1179
1180 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1181 {
1182         if (!bitmap) return 0;
1183
1184         if (behind) {
1185                 atomic_inc(&bitmap->behind_writes);
1186                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1187                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1188         }
1189
1190         while (sectors) {
1191                 int blocks;
1192                 bitmap_counter_t *bmc;
1193
1194                 spin_lock_irq(&bitmap->lock);
1195                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1196                 if (!bmc) {
1197                         spin_unlock_irq(&bitmap->lock);
1198                         return 0;
1199                 }
1200
1201                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1202                         DEFINE_WAIT(__wait);
1203                         /* note that it is safe to do the prepare_to_wait
1204                          * after the test as long as we do it before dropping
1205                          * the spinlock.
1206                          */
1207                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1208                                         TASK_UNINTERRUPTIBLE);
1209                         spin_unlock_irq(&bitmap->lock);
1210                         blk_unplug(bitmap->mddev->queue);
1211                         schedule();
1212                         finish_wait(&bitmap->overflow_wait, &__wait);
1213                         continue;
1214                 }
1215
1216                 switch(*bmc) {
1217                 case 0:
1218                         bitmap_file_set_bit(bitmap, offset);
1219                         bitmap_count_page(bitmap,offset, 1);
1220                         blk_plug_device(bitmap->mddev->queue);
1221                         /* fall through */
1222                 case 1:
1223                         *bmc = 2;
1224                 }
1225
1226                 (*bmc)++;
1227
1228                 spin_unlock_irq(&bitmap->lock);
1229
1230                 offset += blocks;
1231                 if (sectors > blocks)
1232                         sectors -= blocks;
1233                 else sectors = 0;
1234         }
1235         return 0;
1236 }
1237
1238 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1239                      int success, int behind)
1240 {
1241         if (!bitmap) return;
1242         if (behind) {
1243                 atomic_dec(&bitmap->behind_writes);
1244                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1245                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1246         }
1247
1248         while (sectors) {
1249                 int blocks;
1250                 unsigned long flags;
1251                 bitmap_counter_t *bmc;
1252
1253                 spin_lock_irqsave(&bitmap->lock, flags);
1254                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1255                 if (!bmc) {
1256                         spin_unlock_irqrestore(&bitmap->lock, flags);
1257                         return;
1258                 }
1259
1260                 if (!success && ! (*bmc & NEEDED_MASK))
1261                         *bmc |= NEEDED_MASK;
1262
1263                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1264                         wake_up(&bitmap->overflow_wait);
1265
1266                 (*bmc)--;
1267                 if (*bmc <= 2) {
1268                         set_page_attr(bitmap,
1269                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1270                                       BITMAP_PAGE_CLEAN);
1271                 }
1272                 spin_unlock_irqrestore(&bitmap->lock, flags);
1273                 offset += blocks;
1274                 if (sectors > blocks)
1275                         sectors -= blocks;
1276                 else sectors = 0;
1277         }
1278 }
1279
1280 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1281                         int degraded)
1282 {
1283         bitmap_counter_t *bmc;
1284         int rv;
1285         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1286                 *blocks = 1024;
1287                 return 1; /* always resync if no bitmap */
1288         }
1289         spin_lock_irq(&bitmap->lock);
1290         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1291         rv = 0;
1292         if (bmc) {
1293                 /* locked */
1294                 if (RESYNC(*bmc))
1295                         rv = 1;
1296                 else if (NEEDED(*bmc)) {
1297                         rv = 1;
1298                         if (!degraded) { /* don't set/clear bits if degraded */
1299                                 *bmc |= RESYNC_MASK;
1300                                 *bmc &= ~NEEDED_MASK;
1301                         }
1302                 }
1303         }
1304         spin_unlock_irq(&bitmap->lock);
1305         return rv;
1306 }
1307
1308 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1309 {
1310         bitmap_counter_t *bmc;
1311         unsigned long flags;
1312 /*
1313         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1314 */      if (bitmap == NULL) {
1315                 *blocks = 1024;
1316                 return;
1317         }
1318         spin_lock_irqsave(&bitmap->lock, flags);
1319         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1320         if (bmc == NULL)
1321                 goto unlock;
1322         /* locked */
1323 /*
1324         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1325 */
1326         if (RESYNC(*bmc)) {
1327                 *bmc &= ~RESYNC_MASK;
1328
1329                 if (!NEEDED(*bmc) && aborted)
1330                         *bmc |= NEEDED_MASK;
1331                 else {
1332                         if (*bmc <= 2) {
1333                                 set_page_attr(bitmap,
1334                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1335                                               BITMAP_PAGE_CLEAN);
1336                         }
1337                 }
1338         }
1339  unlock:
1340         spin_unlock_irqrestore(&bitmap->lock, flags);
1341 }
1342
1343 void bitmap_close_sync(struct bitmap *bitmap)
1344 {
1345         /* Sync has finished, and any bitmap chunks that weren't synced
1346          * properly have been aborted.  It remains to us to clear the
1347          * RESYNC bit wherever it is still on
1348          */
1349         sector_t sector = 0;
1350         int blocks;
1351         if (!bitmap)
1352                 return;
1353         while (sector < bitmap->mddev->resync_max_sectors) {
1354                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1355                 sector += blocks;
1356         }
1357 }
1358
1359 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1360 {
1361         sector_t s = 0;
1362         int blocks;
1363
1364         if (!bitmap)
1365                 return;
1366         if (sector == 0) {
1367                 bitmap->last_end_sync = jiffies;
1368                 return;
1369         }
1370         if (time_before(jiffies, (bitmap->last_end_sync
1371                                   + bitmap->daemon_sleep * HZ)))
1372                 return;
1373         wait_event(bitmap->mddev->recovery_wait,
1374                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1375
1376         sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
1377         s = 0;
1378         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1379                 bitmap_end_sync(bitmap, s, &blocks, 0);
1380                 s += blocks;
1381         }
1382         bitmap->last_end_sync = jiffies;
1383 }
1384
1385 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1386 {
1387         /* For each chunk covered by any of these sectors, set the
1388          * counter to 1 and set resync_needed.  They should all
1389          * be 0 at this point
1390          */
1391
1392         int secs;
1393         bitmap_counter_t *bmc;
1394         spin_lock_irq(&bitmap->lock);
1395         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1396         if (!bmc) {
1397                 spin_unlock_irq(&bitmap->lock);
1398                 return;
1399         }
1400         if (! *bmc) {
1401                 struct page *page;
1402                 *bmc = 1 | (needed?NEEDED_MASK:0);
1403                 bitmap_count_page(bitmap, offset, 1);
1404                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1405                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1406         }
1407         spin_unlock_irq(&bitmap->lock);
1408
1409 }
1410
1411 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1412 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1413 {
1414         unsigned long chunk;
1415
1416         for (chunk = s; chunk <= e; chunk++) {
1417                 sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
1418                 bitmap_set_memory_bits(bitmap, sec, 1);
1419                 bitmap_file_set_bit(bitmap, sec);
1420         }
1421 }
1422
1423 /*
1424  * flush out any pending updates
1425  */
1426 void bitmap_flush(mddev_t *mddev)
1427 {
1428         struct bitmap *bitmap = mddev->bitmap;
1429         int sleep;
1430
1431         if (!bitmap) /* there was no bitmap */
1432                 return;
1433
1434         /* run the daemon_work three time to ensure everything is flushed
1435          * that can be
1436          */
1437         sleep = bitmap->daemon_sleep;
1438         bitmap->daemon_sleep = 0;
1439         bitmap_daemon_work(bitmap);
1440         bitmap_daemon_work(bitmap);
1441         bitmap_daemon_work(bitmap);
1442         bitmap->daemon_sleep = sleep;
1443         bitmap_update_sb(bitmap);
1444 }
1445
1446 /*
1447  * free memory that was allocated
1448  */
1449 static void bitmap_free(struct bitmap *bitmap)
1450 {
1451         unsigned long k, pages;
1452         struct bitmap_page *bp;
1453
1454         if (!bitmap) /* there was no bitmap */
1455                 return;
1456
1457         /* release the bitmap file and kill the daemon */
1458         bitmap_file_put(bitmap);
1459
1460         bp = bitmap->bp;
1461         pages = bitmap->pages;
1462
1463         /* free all allocated memory */
1464
1465         if (bp) /* deallocate the page memory */
1466                 for (k = 0; k < pages; k++)
1467                         if (bp[k].map && !bp[k].hijacked)
1468                                 kfree(bp[k].map);
1469         kfree(bp);
1470         kfree(bitmap);
1471 }
1472 void bitmap_destroy(mddev_t *mddev)
1473 {
1474         struct bitmap *bitmap = mddev->bitmap;
1475
1476         if (!bitmap) /* there was no bitmap */
1477                 return;
1478
1479         mddev->bitmap = NULL; /* disconnect from the md device */
1480         if (mddev->thread)
1481                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1482
1483         bitmap_free(bitmap);
1484 }
1485
1486 /*
1487  * initialize the bitmap structure
1488  * if this returns an error, bitmap_destroy must be called to do clean up
1489  */
1490 int bitmap_create(mddev_t *mddev)
1491 {
1492         struct bitmap *bitmap;
1493         unsigned long blocks = mddev->resync_max_sectors;
1494         unsigned long chunks;
1495         unsigned long pages;
1496         struct file *file = mddev->bitmap_file;
1497         int err;
1498         sector_t start;
1499
1500         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1501
1502         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1503                 return 0;
1504
1505         BUG_ON(file && mddev->bitmap_offset);
1506
1507         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1508         if (!bitmap)
1509                 return -ENOMEM;
1510
1511         spin_lock_init(&bitmap->lock);
1512         atomic_set(&bitmap->pending_writes, 0);
1513         init_waitqueue_head(&bitmap->write_wait);
1514         init_waitqueue_head(&bitmap->overflow_wait);
1515
1516         bitmap->mddev = mddev;
1517
1518         bitmap->file = file;
1519         bitmap->offset = mddev->bitmap_offset;
1520         if (file) {
1521                 get_file(file);
1522                 do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
1523                                       SYNC_FILE_RANGE_WAIT_BEFORE |
1524                                       SYNC_FILE_RANGE_WRITE |
1525                                       SYNC_FILE_RANGE_WAIT_AFTER);
1526         }
1527         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1528         err = bitmap_read_sb(bitmap);
1529         if (err)
1530                 goto error;
1531
1532         bitmap->chunkshift = ffz(~bitmap->chunksize);
1533
1534         /* now that chunksize and chunkshift are set, we can use these macros */
1535         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1536                         CHUNK_BLOCK_RATIO(bitmap);
1537         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1538
1539         BUG_ON(!pages);
1540
1541         bitmap->chunks = chunks;
1542         bitmap->pages = pages;
1543         bitmap->missing_pages = pages;
1544         bitmap->counter_bits = COUNTER_BITS;
1545
1546         bitmap->syncchunk = ~0UL;
1547
1548 #ifdef INJECT_FATAL_FAULT_1
1549         bitmap->bp = NULL;
1550 #else
1551         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1552 #endif
1553         err = -ENOMEM;
1554         if (!bitmap->bp)
1555                 goto error;
1556
1557         /* now that we have some pages available, initialize the in-memory
1558          * bitmap from the on-disk bitmap */
1559         start = 0;
1560         if (mddev->degraded == 0
1561             || bitmap->events_cleared == mddev->events)
1562                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1563                 start = mddev->recovery_cp;
1564         err = bitmap_init_from_disk(bitmap, start);
1565
1566         if (err)
1567                 goto error;
1568
1569         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1570                 pages, bmname(bitmap));
1571
1572         mddev->bitmap = bitmap;
1573
1574         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1575
1576         bitmap_update_sb(bitmap);
1577
1578         return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
1579
1580  error:
1581         bitmap_free(bitmap);
1582         return err;
1583 }
1584
1585 /* the bitmap API -- for raid personalities */
1586 EXPORT_SYMBOL(bitmap_startwrite);
1587 EXPORT_SYMBOL(bitmap_endwrite);
1588 EXPORT_SYMBOL(bitmap_start_sync);
1589 EXPORT_SYMBOL(bitmap_end_sync);
1590 EXPORT_SYMBOL(bitmap_unplug);
1591 EXPORT_SYMBOL(bitmap_close_sync);
1592 EXPORT_SYMBOL(bitmap_cond_end_sync);