[PATCH] md: new sysfs interface for setting bits in the write-intent-bitmap
[sfrench/cifs-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_dentry;
216         v = file->f_vfsmnt;
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         ITERATE_RDEV(mddev, rdev, tmp) {
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(mddev_t *mddev, long offset, struct page *page, int wait)
259 {
260         mdk_rdev_t *rdev;
261         struct list_head *tmp;
262
263         ITERATE_RDEV(mddev, rdev, tmp)
264                 if (test_bit(In_sync, &rdev->flags)
265                     && !test_bit(Faulty, &rdev->flags))
266                         md_super_write(mddev, rdev,
267                                        (rdev->sb_offset<<1) + offset
268                                        + page->index * (PAGE_SIZE/512),
269                                        PAGE_SIZE,
270                                        page);
271
272         if (wait)
273                 md_super_wait(mddev);
274         return 0;
275 }
276
277 /*
278  * write out a page to a file
279  */
280 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
281 {
282         struct buffer_head *bh;
283
284         if (bitmap->file == NULL)
285                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
286
287         bh = page_buffers(page);
288
289         while (bh && bh->b_blocknr) {
290                 atomic_inc(&bitmap->pending_writes);
291                 set_buffer_locked(bh);
292                 set_buffer_mapped(bh);
293                 submit_bh(WRITE, bh);
294                 bh = bh->b_this_page;
295         }
296
297         if (wait) {
298                 wait_event(bitmap->write_wait,
299                            atomic_read(&bitmap->pending_writes)==0);
300                 return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
301         }
302         return 0;
303 }
304
305 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
306 {
307         struct bitmap *bitmap = bh->b_private;
308         unsigned long flags;
309
310         if (!uptodate) {
311                 spin_lock_irqsave(&bitmap->lock, flags);
312                 bitmap->flags |= BITMAP_WRITE_ERROR;
313                 spin_unlock_irqrestore(&bitmap->lock, flags);
314         }
315         if (atomic_dec_and_test(&bitmap->pending_writes))
316                 wake_up(&bitmap->write_wait);
317 }
318
319 /* copied from buffer.c */
320 static void
321 __clear_page_buffers(struct page *page)
322 {
323         ClearPagePrivate(page);
324         set_page_private(page, 0);
325         page_cache_release(page);
326 }
327 static void free_buffers(struct page *page)
328 {
329         struct buffer_head *bh = page_buffers(page);
330
331         while (bh) {
332                 struct buffer_head *next = bh->b_this_page;
333                 free_buffer_head(bh);
334                 bh = next;
335         }
336         __clear_page_buffers(page);
337         put_page(page);
338 }
339
340 /* read a page from a file.
341  * We both read the page, and attach buffers to the page to record the
342  * address of each block (using bmap).  These addresses will be used
343  * to write the block later, completely bypassing the filesystem.
344  * This usage is similar to how swap files are handled, and allows us
345  * to write to a file with no concerns of memory allocation failing.
346  */
347 static struct page *read_page(struct file *file, unsigned long index,
348                               struct bitmap *bitmap,
349                               unsigned long count)
350 {
351         struct page *page = NULL;
352         struct inode *inode = file->f_dentry->d_inode;
353         struct buffer_head *bh;
354         sector_t block;
355
356         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
357                         (unsigned long long)index << PAGE_SHIFT);
358
359         page = alloc_page(GFP_KERNEL);
360         if (!page)
361                 page = ERR_PTR(-ENOMEM);
362         if (IS_ERR(page))
363                 goto out;
364
365         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
366         if (!bh) {
367                 put_page(page);
368                 page = ERR_PTR(-ENOMEM);
369                 goto out;
370         }
371         attach_page_buffers(page, bh);
372         block = index << (PAGE_SHIFT - inode->i_blkbits);
373         while (bh) {
374                 if (count == 0)
375                         bh->b_blocknr = 0;
376                 else {
377                         bh->b_blocknr = bmap(inode, block);
378                         if (bh->b_blocknr == 0) {
379                                 /* Cannot use this file! */
380                                 free_buffers(page);
381                                 page = ERR_PTR(-EINVAL);
382                                 goto out;
383                         }
384                         bh->b_bdev = inode->i_sb->s_bdev;
385                         if (count < (1<<inode->i_blkbits))
386                                 count = 0;
387                         else
388                                 count -= (1<<inode->i_blkbits);
389
390                         bh->b_end_io = end_bitmap_write;
391                         bh->b_private = bitmap;
392                         atomic_inc(&bitmap->pending_writes);
393                         set_buffer_locked(bh);
394                         set_buffer_mapped(bh);
395                         submit_bh(READ, bh);
396                 }
397                 block++;
398                 bh = bh->b_this_page;
399         }
400         page->index = index;
401
402         wait_event(bitmap->write_wait,
403                    atomic_read(&bitmap->pending_writes)==0);
404         if (bitmap->flags & BITMAP_WRITE_ERROR) {
405                 free_buffers(page);
406                 page = ERR_PTR(-EIO);
407         }
408 out:
409         if (IS_ERR(page))
410                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
411                         (int)PAGE_SIZE,
412                         (unsigned long long)index << PAGE_SHIFT,
413                         PTR_ERR(page));
414         return page;
415 }
416
417 /*
418  * bitmap file superblock operations
419  */
420
421 /* update the event counter and sync the superblock to disk */
422 int bitmap_update_sb(struct bitmap *bitmap)
423 {
424         bitmap_super_t *sb;
425         unsigned long flags;
426
427         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
428                 return 0;
429         spin_lock_irqsave(&bitmap->lock, flags);
430         if (!bitmap->sb_page) { /* no superblock */
431                 spin_unlock_irqrestore(&bitmap->lock, flags);
432                 return 0;
433         }
434         spin_unlock_irqrestore(&bitmap->lock, flags);
435         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
436         sb->events = cpu_to_le64(bitmap->mddev->events);
437         if (!bitmap->mddev->degraded)
438                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
439         kunmap_atomic(sb, KM_USER0);
440         return write_page(bitmap, bitmap->sb_page, 1);
441 }
442
443 /* print out the bitmap file superblock */
444 void bitmap_print_sb(struct bitmap *bitmap)
445 {
446         bitmap_super_t *sb;
447
448         if (!bitmap || !bitmap->sb_page)
449                 return;
450         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
451         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
452         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
453         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
454         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
455                                         *(__u32 *)(sb->uuid+0),
456                                         *(__u32 *)(sb->uuid+4),
457                                         *(__u32 *)(sb->uuid+8),
458                                         *(__u32 *)(sb->uuid+12));
459         printk(KERN_DEBUG "        events: %llu\n",
460                         (unsigned long long) le64_to_cpu(sb->events));
461         printk(KERN_DEBUG "events cleared: %llu\n",
462                         (unsigned long long) le64_to_cpu(sb->events_cleared));
463         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
464         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
465         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
466         printk(KERN_DEBUG "     sync size: %llu KB\n",
467                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
468         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
469         kunmap_atomic(sb, KM_USER0);
470 }
471
472 /* read the superblock from the bitmap file and initialize some bitmap fields */
473 static int bitmap_read_sb(struct bitmap *bitmap)
474 {
475         char *reason = NULL;
476         bitmap_super_t *sb;
477         unsigned long chunksize, daemon_sleep, write_behind;
478         unsigned long long events;
479         int err = -EINVAL;
480
481         /* page 0 is the superblock, read it... */
482         if (bitmap->file)
483                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
484         else {
485                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
486         }
487         if (IS_ERR(bitmap->sb_page)) {
488                 err = PTR_ERR(bitmap->sb_page);
489                 bitmap->sb_page = NULL;
490                 return err;
491         }
492
493         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
494
495         chunksize = le32_to_cpu(sb->chunksize);
496         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
497         write_behind = le32_to_cpu(sb->write_behind);
498
499         /* verify that the bitmap-specific fields are valid */
500         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
501                 reason = "bad magic";
502         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
503                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
504                 reason = "unrecognized superblock version";
505         else if (chunksize < PAGE_SIZE)
506                 reason = "bitmap chunksize too small";
507         else if ((1 << ffz(~chunksize)) != chunksize)
508                 reason = "bitmap chunksize not a power of 2";
509         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
510                 reason = "daemon sleep period out of range";
511         else if (write_behind > COUNTER_MAX)
512                 reason = "write-behind limit out of range (0 - 16383)";
513         if (reason) {
514                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
515                         bmname(bitmap), reason);
516                 goto out;
517         }
518
519         /* keep the array size field of the bitmap superblock up to date */
520         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
521
522         if (!bitmap->mddev->persistent)
523                 goto success;
524
525         /*
526          * if we have a persistent array superblock, compare the
527          * bitmap's UUID and event counter to the mddev's
528          */
529         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
530                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
531                         bmname(bitmap));
532                 goto out;
533         }
534         events = le64_to_cpu(sb->events);
535         if (events < bitmap->mddev->events) {
536                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
537                         "-- forcing full recovery\n", bmname(bitmap), events,
538                         (unsigned long long) bitmap->mddev->events);
539                 sb->state |= BITMAP_STALE;
540         }
541 success:
542         /* assign fields using values from superblock */
543         bitmap->chunksize = chunksize;
544         bitmap->daemon_sleep = daemon_sleep;
545         bitmap->daemon_lastrun = jiffies;
546         bitmap->max_write_behind = write_behind;
547         bitmap->flags |= sb->state;
548         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
549                 bitmap->flags |= BITMAP_HOSTENDIAN;
550         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
551         if (sb->state & BITMAP_STALE)
552                 bitmap->events_cleared = bitmap->mddev->events;
553         err = 0;
554 out:
555         kunmap_atomic(sb, KM_USER0);
556         if (err)
557                 bitmap_print_sb(bitmap);
558         return err;
559 }
560
561 enum bitmap_mask_op {
562         MASK_SET,
563         MASK_UNSET
564 };
565
566 /* record the state of the bitmap in the superblock */
567 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
568                                 enum bitmap_mask_op op)
569 {
570         bitmap_super_t *sb;
571         unsigned long flags;
572
573         spin_lock_irqsave(&bitmap->lock, flags);
574         if (!bitmap->sb_page) { /* can't set the state */
575                 spin_unlock_irqrestore(&bitmap->lock, flags);
576                 return;
577         }
578         spin_unlock_irqrestore(&bitmap->lock, flags);
579         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
580         switch (op) {
581                 case MASK_SET: sb->state |= bits;
582                                 break;
583                 case MASK_UNSET: sb->state &= ~bits;
584                                 break;
585                 default: BUG();
586         }
587         kunmap_atomic(sb, KM_USER0);
588 }
589
590 /*
591  * general bitmap file operations
592  */
593
594 /* calculate the index of the page that contains this bit */
595 static inline unsigned long file_page_index(unsigned long chunk)
596 {
597         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
598 }
599
600 /* calculate the (bit) offset of this bit within a page */
601 static inline unsigned long file_page_offset(unsigned long chunk)
602 {
603         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
604 }
605
606 /*
607  * return a pointer to the page in the filemap that contains the given bit
608  *
609  * this lookup is complicated by the fact that the bitmap sb might be exactly
610  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
611  * 0 or page 1
612  */
613 static inline struct page *filemap_get_page(struct bitmap *bitmap,
614                                         unsigned long chunk)
615 {
616         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
617         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
618 }
619
620
621 static void bitmap_file_unmap(struct bitmap *bitmap)
622 {
623         struct page **map, *sb_page;
624         unsigned long *attr;
625         int pages;
626         unsigned long flags;
627
628         spin_lock_irqsave(&bitmap->lock, flags);
629         map = bitmap->filemap;
630         bitmap->filemap = NULL;
631         attr = bitmap->filemap_attr;
632         bitmap->filemap_attr = NULL;
633         pages = bitmap->file_pages;
634         bitmap->file_pages = 0;
635         sb_page = bitmap->sb_page;
636         bitmap->sb_page = NULL;
637         spin_unlock_irqrestore(&bitmap->lock, flags);
638
639         while (pages--)
640                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
641                         free_buffers(map[pages]);
642         kfree(map);
643         kfree(attr);
644
645         if (sb_page)
646                 free_buffers(sb_page);
647 }
648
649 static void bitmap_file_put(struct bitmap *bitmap)
650 {
651         struct file *file;
652         unsigned long flags;
653
654         spin_lock_irqsave(&bitmap->lock, flags);
655         file = bitmap->file;
656         bitmap->file = NULL;
657         spin_unlock_irqrestore(&bitmap->lock, flags);
658
659         if (file)
660                 wait_event(bitmap->write_wait,
661                            atomic_read(&bitmap->pending_writes)==0);
662         bitmap_file_unmap(bitmap);
663
664         if (file) {
665                 struct inode *inode = file->f_dentry->d_inode;
666                 invalidate_inode_pages(inode->i_mapping);
667                 fput(file);
668         }
669 }
670
671
672 /*
673  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
674  * then it is no longer reliable, so we stop using it and we mark the file
675  * as failed in the superblock
676  */
677 static void bitmap_file_kick(struct bitmap *bitmap)
678 {
679         char *path, *ptr = NULL;
680
681         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
682         bitmap_update_sb(bitmap);
683
684         if (bitmap->file) {
685                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
686                 if (path)
687                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
688
689                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
690                        bmname(bitmap), ptr ? ptr : "");
691
692                 kfree(path);
693         }
694
695         bitmap_file_put(bitmap);
696
697         return;
698 }
699
700 enum bitmap_page_attr {
701         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
702         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
703         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
704 };
705
706 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
707                                 enum bitmap_page_attr attr)
708 {
709         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
710 }
711
712 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
713                                 enum bitmap_page_attr attr)
714 {
715         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
716 }
717
718 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
719                                            enum bitmap_page_attr attr)
720 {
721         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
722 }
723
724 /*
725  * bitmap_file_set_bit -- called before performing a write to the md device
726  * to set (and eventually sync) a particular bit in the bitmap file
727  *
728  * we set the bit immediately, then we record the page number so that
729  * when an unplug occurs, we can flush the dirty pages out to disk
730  */
731 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
732 {
733         unsigned long bit;
734         struct page *page;
735         void *kaddr;
736         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
737
738         if (!bitmap->filemap) {
739                 return;
740         }
741
742         page = filemap_get_page(bitmap, chunk);
743         if (!page) return;
744         bit = file_page_offset(chunk);
745
746         /* set the bit */
747         kaddr = kmap_atomic(page, KM_USER0);
748         if (bitmap->flags & BITMAP_HOSTENDIAN)
749                 set_bit(bit, kaddr);
750         else
751                 ext2_set_bit(bit, kaddr);
752         kunmap_atomic(kaddr, KM_USER0);
753         PRINTK("set file bit %lu page %lu\n", bit, page->index);
754
755         /* record page number so it gets flushed to disk when unplug occurs */
756         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
757
758 }
759
760 /* this gets called when the md device is ready to unplug its underlying
761  * (slave) device queues -- before we let any writes go down, we need to
762  * sync the dirty pages of the bitmap file to disk */
763 int bitmap_unplug(struct bitmap *bitmap)
764 {
765         unsigned long i, flags;
766         int dirty, need_write;
767         struct page *page;
768         int wait = 0;
769         int err;
770
771         if (!bitmap)
772                 return 0;
773
774         /* look at each page to see if there are any set bits that need to be
775          * flushed out to disk */
776         for (i = 0; i < bitmap->file_pages; i++) {
777                 spin_lock_irqsave(&bitmap->lock, flags);
778                 if (!bitmap->filemap) {
779                         spin_unlock_irqrestore(&bitmap->lock, flags);
780                         return 0;
781                 }
782                 page = bitmap->filemap[i];
783                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
784                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
785                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
786                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
787                 if (dirty)
788                         wait = 1;
789                 spin_unlock_irqrestore(&bitmap->lock, flags);
790
791                 if (dirty | need_write)
792                         err = write_page(bitmap, page, 0);
793         }
794         if (wait) { /* if any writes were performed, we need to wait on them */
795                 if (bitmap->file)
796                         wait_event(bitmap->write_wait,
797                                    atomic_read(&bitmap->pending_writes)==0);
798                 else
799                         md_super_wait(bitmap->mddev);
800         }
801         if (bitmap->flags & BITMAP_WRITE_ERROR)
802                 bitmap_file_kick(bitmap);
803         return 0;
804 }
805
806 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
807 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
808  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
809  * memory mapping of the bitmap file
810  * Special cases:
811  *   if there's no bitmap file, or if the bitmap file had been
812  *   previously kicked from the array, we mark all the bits as
813  *   1's in order to cause a full resync.
814  *
815  * We ignore all bits for sectors that end earlier than 'start'.
816  * This is used when reading an out-of-date bitmap...
817  */
818 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
819 {
820         unsigned long i, chunks, index, oldindex, bit;
821         struct page *page = NULL, *oldpage = NULL;
822         unsigned long num_pages, bit_cnt = 0;
823         struct file *file;
824         unsigned long bytes, offset;
825         int outofdate;
826         int ret = -ENOSPC;
827         void *paddr;
828
829         chunks = bitmap->chunks;
830         file = bitmap->file;
831
832         BUG_ON(!file && !bitmap->offset);
833
834 #ifdef INJECT_FAULTS_3
835         outofdate = 1;
836 #else
837         outofdate = bitmap->flags & BITMAP_STALE;
838 #endif
839         if (outofdate)
840                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
841                         "recovery\n", bmname(bitmap));
842
843         bytes = (chunks + 7) / 8;
844
845         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
846
847         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
848                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
849                         bmname(bitmap),
850                         (unsigned long) i_size_read(file->f_mapping->host),
851                         bytes + sizeof(bitmap_super_t));
852                 goto out;
853         }
854
855         ret = -ENOMEM;
856
857         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
858         if (!bitmap->filemap)
859                 goto out;
860
861         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
862         bitmap->filemap_attr = kzalloc(
863                 (((num_pages*4/8)+sizeof(unsigned long)-1)
864                  /sizeof(unsigned long))
865                 *sizeof(unsigned long),
866                 GFP_KERNEL);
867         if (!bitmap->filemap_attr)
868                 goto out;
869
870         oldindex = ~0L;
871
872         for (i = 0; i < chunks; i++) {
873                 int b;
874                 index = file_page_index(i);
875                 bit = file_page_offset(i);
876                 if (index != oldindex) { /* this is a new page, read it in */
877                         int count;
878                         /* unmap the old page, we're done with it */
879                         if (index == num_pages-1)
880                                 count = bytes - index * PAGE_SIZE;
881                         else
882                                 count = PAGE_SIZE;
883                         if (index == 0) {
884                                 /*
885                                  * if we're here then the superblock page
886                                  * contains some bits (PAGE_SIZE != sizeof sb)
887                                  * we've already read it in, so just use it
888                                  */
889                                 page = bitmap->sb_page;
890                                 offset = sizeof(bitmap_super_t);
891                         } else if (file) {
892                                 page = read_page(file, index, bitmap, count);
893                                 offset = 0;
894                         } else {
895                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
896                                 offset = 0;
897                         }
898                         if (IS_ERR(page)) { /* read error */
899                                 ret = PTR_ERR(page);
900                                 goto out;
901                         }
902
903                         oldindex = index;
904                         oldpage = page;
905
906                         if (outofdate) {
907                                 /*
908                                  * if bitmap is out of date, dirty the
909                                  * whole page and write it out
910                                  */
911                                 paddr = kmap_atomic(page, KM_USER0);
912                                 memset(paddr + offset, 0xff,
913                                        PAGE_SIZE - offset);
914                                 kunmap_atomic(paddr, KM_USER0);
915                                 ret = write_page(bitmap, page, 1);
916                                 if (ret) {
917                                         /* release, page not in filemap yet */
918                                         put_page(page);
919                                         goto out;
920                                 }
921                         }
922
923                         bitmap->filemap[bitmap->file_pages++] = page;
924                 }
925                 paddr = kmap_atomic(page, KM_USER0);
926                 if (bitmap->flags & BITMAP_HOSTENDIAN)
927                         b = test_bit(bit, paddr);
928                 else
929                         b = ext2_test_bit(bit, paddr);
930                 kunmap_atomic(paddr, KM_USER0);
931                 if (b) {
932                         /* if the disk bit is set, set the memory bit */
933                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
934                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
935                                 );
936                         bit_cnt++;
937                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
938                 }
939         }
940
941         /* everything went OK */
942         ret = 0;
943         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
944
945         if (bit_cnt) { /* Kick recovery if any bits were set */
946                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
947                 md_wakeup_thread(bitmap->mddev->thread);
948         }
949
950 out:
951         printk(KERN_INFO "%s: bitmap initialized from disk: "
952                 "read %lu/%lu pages, set %lu bits, status: %d\n",
953                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
954
955         return ret;
956 }
957
958 void bitmap_write_all(struct bitmap *bitmap)
959 {
960         /* We don't actually write all bitmap blocks here,
961          * just flag them as needing to be written
962          */
963         int i;
964
965         for (i=0; i < bitmap->file_pages; i++)
966                 set_page_attr(bitmap, bitmap->filemap[i],
967                               BITMAP_PAGE_NEEDWRITE);
968 }
969
970
971 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
972 {
973         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
974         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
975         bitmap->bp[page].count += inc;
976 /*
977         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
978                               (unsigned long long)offset, inc, bitmap->bp[page].count);
979 */
980         bitmap_checkfree(bitmap, page);
981 }
982 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
983                                             sector_t offset, int *blocks,
984                                             int create);
985
986 /*
987  * bitmap daemon -- periodically wakes up to clean bits and flush pages
988  *                      out to disk
989  */
990
991 int bitmap_daemon_work(struct bitmap *bitmap)
992 {
993         unsigned long j;
994         unsigned long flags;
995         struct page *page = NULL, *lastpage = NULL;
996         int err = 0;
997         int blocks;
998         void *paddr;
999
1000         if (bitmap == NULL)
1001                 return 0;
1002         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1003                 return 0;
1004         bitmap->daemon_lastrun = jiffies;
1005
1006         for (j = 0; j < bitmap->chunks; j++) {
1007                 bitmap_counter_t *bmc;
1008                 spin_lock_irqsave(&bitmap->lock, flags);
1009                 if (!bitmap->filemap) {
1010                         /* error or shutdown */
1011                         spin_unlock_irqrestore(&bitmap->lock, flags);
1012                         break;
1013                 }
1014
1015                 page = filemap_get_page(bitmap, j);
1016
1017                 if (page != lastpage) {
1018                         /* skip this page unless it's marked as needing cleaning */
1019                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1020                                 int need_write = test_page_attr(bitmap, page,
1021                                                                 BITMAP_PAGE_NEEDWRITE);
1022                                 if (need_write)
1023                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1024
1025                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1026                                 if (need_write) {
1027                                         switch (write_page(bitmap, page, 0)) {
1028                                         case 0:
1029                                                 break;
1030                                         default:
1031                                                 bitmap_file_kick(bitmap);
1032                                         }
1033                                 }
1034                                 continue;
1035                         }
1036
1037                         /* grab the new page, sync and release the old */
1038                         if (lastpage != NULL) {
1039                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1040                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1041                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1042                                         err = write_page(bitmap, lastpage, 0);
1043                                 } else {
1044                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1045                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1046                                 }
1047                                 if (err)
1048                                         bitmap_file_kick(bitmap);
1049                         } else
1050                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1051                         lastpage = page;
1052 /*
1053                         printk("bitmap clean at page %lu\n", j);
1054 */
1055                         spin_lock_irqsave(&bitmap->lock, flags);
1056                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1057                 }
1058                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1059                                         &blocks, 0);
1060                 if (bmc) {
1061 /*
1062   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1063 */
1064                         if (*bmc == 2) {
1065                                 *bmc=1; /* maybe clear the bit next time */
1066                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1067                         } else if (*bmc == 1) {
1068                                 /* we can clear the bit */
1069                                 *bmc = 0;
1070                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1071                                                   -1);
1072
1073                                 /* clear the bit */
1074                                 paddr = kmap_atomic(page, KM_USER0);
1075                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1076                                         clear_bit(file_page_offset(j), paddr);
1077                                 else
1078                                         ext2_clear_bit(file_page_offset(j), paddr);
1079                                 kunmap_atomic(paddr, KM_USER0);
1080                         }
1081                 }
1082                 spin_unlock_irqrestore(&bitmap->lock, flags);
1083         }
1084
1085         /* now sync the final page */
1086         if (lastpage != NULL) {
1087                 spin_lock_irqsave(&bitmap->lock, flags);
1088                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1089                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1090                         spin_unlock_irqrestore(&bitmap->lock, flags);
1091                         err = write_page(bitmap, lastpage, 0);
1092                 } else {
1093                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1094                         spin_unlock_irqrestore(&bitmap->lock, flags);
1095                 }
1096         }
1097
1098         return err;
1099 }
1100
1101 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1102                                             sector_t offset, int *blocks,
1103                                             int create)
1104 {
1105         /* If 'create', we might release the lock and reclaim it.
1106          * The lock must have been taken with interrupts enabled.
1107          * If !create, we don't release the lock.
1108          */
1109         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1110         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1111         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1112         sector_t csize;
1113
1114         if (bitmap_checkpage(bitmap, page, create) < 0) {
1115                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1116                 *blocks = csize - (offset & (csize- 1));
1117                 return NULL;
1118         }
1119         /* now locked ... */
1120
1121         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1122                 /* should we use the first or second counter field
1123                  * of the hijacked pointer? */
1124                 int hi = (pageoff > PAGE_COUNTER_MASK);
1125                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1126                                           PAGE_COUNTER_SHIFT - 1);
1127                 *blocks = csize - (offset & (csize- 1));
1128                 return  &((bitmap_counter_t *)
1129                           &bitmap->bp[page].map)[hi];
1130         } else { /* page is allocated */
1131                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1132                 *blocks = csize - (offset & (csize- 1));
1133                 return (bitmap_counter_t *)
1134                         &(bitmap->bp[page].map[pageoff]);
1135         }
1136 }
1137
1138 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1139 {
1140         if (!bitmap) return 0;
1141
1142         if (behind) {
1143                 atomic_inc(&bitmap->behind_writes);
1144                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1145                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1146         }
1147
1148         while (sectors) {
1149                 int blocks;
1150                 bitmap_counter_t *bmc;
1151
1152                 spin_lock_irq(&bitmap->lock);
1153                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1154                 if (!bmc) {
1155                         spin_unlock_irq(&bitmap->lock);
1156                         return 0;
1157                 }
1158
1159                 switch(*bmc) {
1160                 case 0:
1161                         bitmap_file_set_bit(bitmap, offset);
1162                         bitmap_count_page(bitmap,offset, 1);
1163                         blk_plug_device(bitmap->mddev->queue);
1164                         /* fall through */
1165                 case 1:
1166                         *bmc = 2;
1167                 }
1168                 BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
1169                 (*bmc)++;
1170
1171                 spin_unlock_irq(&bitmap->lock);
1172
1173                 offset += blocks;
1174                 if (sectors > blocks)
1175                         sectors -= blocks;
1176                 else sectors = 0;
1177         }
1178         return 0;
1179 }
1180
1181 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1182                      int success, int behind)
1183 {
1184         if (!bitmap) return;
1185         if (behind) {
1186                 atomic_dec(&bitmap->behind_writes);
1187                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1188                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1189         }
1190
1191         while (sectors) {
1192                 int blocks;
1193                 unsigned long flags;
1194                 bitmap_counter_t *bmc;
1195
1196                 spin_lock_irqsave(&bitmap->lock, flags);
1197                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1198                 if (!bmc) {
1199                         spin_unlock_irqrestore(&bitmap->lock, flags);
1200                         return;
1201                 }
1202
1203                 if (!success && ! (*bmc & NEEDED_MASK))
1204                         *bmc |= NEEDED_MASK;
1205
1206                 (*bmc)--;
1207                 if (*bmc <= 2) {
1208                         set_page_attr(bitmap,
1209                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1210                                       BITMAP_PAGE_CLEAN);
1211                 }
1212                 spin_unlock_irqrestore(&bitmap->lock, flags);
1213                 offset += blocks;
1214                 if (sectors > blocks)
1215                         sectors -= blocks;
1216                 else sectors = 0;
1217         }
1218 }
1219
1220 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1221                         int degraded)
1222 {
1223         bitmap_counter_t *bmc;
1224         int rv;
1225         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1226                 *blocks = 1024;
1227                 return 1; /* always resync if no bitmap */
1228         }
1229         spin_lock_irq(&bitmap->lock);
1230         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1231         rv = 0;
1232         if (bmc) {
1233                 /* locked */
1234                 if (RESYNC(*bmc))
1235                         rv = 1;
1236                 else if (NEEDED(*bmc)) {
1237                         rv = 1;
1238                         if (!degraded) { /* don't set/clear bits if degraded */
1239                                 *bmc |= RESYNC_MASK;
1240                                 *bmc &= ~NEEDED_MASK;
1241                         }
1242                 }
1243         }
1244         spin_unlock_irq(&bitmap->lock);
1245         return rv;
1246 }
1247
1248 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1249 {
1250         bitmap_counter_t *bmc;
1251         unsigned long flags;
1252 /*
1253         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1254 */      if (bitmap == NULL) {
1255                 *blocks = 1024;
1256                 return;
1257         }
1258         spin_lock_irqsave(&bitmap->lock, flags);
1259         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1260         if (bmc == NULL)
1261                 goto unlock;
1262         /* locked */
1263 /*
1264         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1265 */
1266         if (RESYNC(*bmc)) {
1267                 *bmc &= ~RESYNC_MASK;
1268
1269                 if (!NEEDED(*bmc) && aborted)
1270                         *bmc |= NEEDED_MASK;
1271                 else {
1272                         if (*bmc <= 2) {
1273                                 set_page_attr(bitmap,
1274                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1275                                               BITMAP_PAGE_CLEAN);
1276                         }
1277                 }
1278         }
1279  unlock:
1280         spin_unlock_irqrestore(&bitmap->lock, flags);
1281 }
1282
1283 void bitmap_close_sync(struct bitmap *bitmap)
1284 {
1285         /* Sync has finished, and any bitmap chunks that weren't synced
1286          * properly have been aborted.  It remains to us to clear the
1287          * RESYNC bit wherever it is still on
1288          */
1289         sector_t sector = 0;
1290         int blocks;
1291         if (!bitmap) return;
1292         while (sector < bitmap->mddev->resync_max_sectors) {
1293                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1294 /*
1295                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1296                                          (unsigned long long)sector, blocks);
1297 */              sector += blocks;
1298         }
1299 }
1300
1301 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1302 {
1303         /* For each chunk covered by any of these sectors, set the
1304          * counter to 1 and set resync_needed.  They should all
1305          * be 0 at this point
1306          */
1307
1308         int secs;
1309         bitmap_counter_t *bmc;
1310         spin_lock_irq(&bitmap->lock);
1311         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1312         if (!bmc) {
1313                 spin_unlock_irq(&bitmap->lock);
1314                 return;
1315         }
1316         if (! *bmc) {
1317                 struct page *page;
1318                 *bmc = 1 | (needed?NEEDED_MASK:0);
1319                 bitmap_count_page(bitmap, offset, 1);
1320                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1321                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1322         }
1323         spin_unlock_irq(&bitmap->lock);
1324
1325 }
1326
1327 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1328 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1329 {
1330         unsigned long chunk;
1331
1332         for (chunk = s; chunk <= e; chunk++) {
1333                 sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
1334                 bitmap_set_memory_bits(bitmap, sec, 1);
1335                 bitmap_file_set_bit(bitmap, sec);
1336         }
1337 }
1338
1339 /*
1340  * flush out any pending updates
1341  */
1342 void bitmap_flush(mddev_t *mddev)
1343 {
1344         struct bitmap *bitmap = mddev->bitmap;
1345         int sleep;
1346
1347         if (!bitmap) /* there was no bitmap */
1348                 return;
1349
1350         /* run the daemon_work three time to ensure everything is flushed
1351          * that can be
1352          */
1353         sleep = bitmap->daemon_sleep;
1354         bitmap->daemon_sleep = 0;
1355         bitmap_daemon_work(bitmap);
1356         bitmap_daemon_work(bitmap);
1357         bitmap_daemon_work(bitmap);
1358         bitmap->daemon_sleep = sleep;
1359         bitmap_update_sb(bitmap);
1360 }
1361
1362 /*
1363  * free memory that was allocated
1364  */
1365 static void bitmap_free(struct bitmap *bitmap)
1366 {
1367         unsigned long k, pages;
1368         struct bitmap_page *bp;
1369
1370         if (!bitmap) /* there was no bitmap */
1371                 return;
1372
1373         /* release the bitmap file and kill the daemon */
1374         bitmap_file_put(bitmap);
1375
1376         bp = bitmap->bp;
1377         pages = bitmap->pages;
1378
1379         /* free all allocated memory */
1380
1381         if (bp) /* deallocate the page memory */
1382                 for (k = 0; k < pages; k++)
1383                         if (bp[k].map && !bp[k].hijacked)
1384                                 kfree(bp[k].map);
1385         kfree(bp);
1386         kfree(bitmap);
1387 }
1388 void bitmap_destroy(mddev_t *mddev)
1389 {
1390         struct bitmap *bitmap = mddev->bitmap;
1391
1392         if (!bitmap) /* there was no bitmap */
1393                 return;
1394
1395         mddev->bitmap = NULL; /* disconnect from the md device */
1396         if (mddev->thread)
1397                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1398
1399         bitmap_free(bitmap);
1400 }
1401
1402 /*
1403  * initialize the bitmap structure
1404  * if this returns an error, bitmap_destroy must be called to do clean up
1405  */
1406 int bitmap_create(mddev_t *mddev)
1407 {
1408         struct bitmap *bitmap;
1409         unsigned long blocks = mddev->resync_max_sectors;
1410         unsigned long chunks;
1411         unsigned long pages;
1412         struct file *file = mddev->bitmap_file;
1413         int err;
1414         sector_t start;
1415
1416         BUG_ON(sizeof(bitmap_super_t) != 256);
1417
1418         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1419                 return 0;
1420
1421         BUG_ON(file && mddev->bitmap_offset);
1422
1423         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1424         if (!bitmap)
1425                 return -ENOMEM;
1426
1427         spin_lock_init(&bitmap->lock);
1428         atomic_set(&bitmap->pending_writes, 0);
1429         init_waitqueue_head(&bitmap->write_wait);
1430
1431         bitmap->mddev = mddev;
1432
1433         bitmap->file = file;
1434         bitmap->offset = mddev->bitmap_offset;
1435         if (file) {
1436                 get_file(file);
1437                 do_sync_file_range(file, 0, LLONG_MAX,
1438                                    SYNC_FILE_RANGE_WAIT_BEFORE |
1439                                    SYNC_FILE_RANGE_WRITE |
1440                                    SYNC_FILE_RANGE_WAIT_AFTER);
1441         }
1442         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1443         err = bitmap_read_sb(bitmap);
1444         if (err)
1445                 goto error;
1446
1447         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1448                                         sizeof(bitmap->chunksize));
1449
1450         /* now that chunksize and chunkshift are set, we can use these macros */
1451         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1452                         CHUNK_BLOCK_RATIO(bitmap);
1453         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1454
1455         BUG_ON(!pages);
1456
1457         bitmap->chunks = chunks;
1458         bitmap->pages = pages;
1459         bitmap->missing_pages = pages;
1460         bitmap->counter_bits = COUNTER_BITS;
1461
1462         bitmap->syncchunk = ~0UL;
1463
1464 #ifdef INJECT_FATAL_FAULT_1
1465         bitmap->bp = NULL;
1466 #else
1467         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1468 #endif
1469         err = -ENOMEM;
1470         if (!bitmap->bp)
1471                 goto error;
1472
1473         /* now that we have some pages available, initialize the in-memory
1474          * bitmap from the on-disk bitmap */
1475         start = 0;
1476         if (mddev->degraded == 0
1477             || bitmap->events_cleared == mddev->events)
1478                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1479                 start = mddev->recovery_cp;
1480         err = bitmap_init_from_disk(bitmap, start);
1481
1482         if (err)
1483                 goto error;
1484
1485         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1486                 pages, bmname(bitmap));
1487
1488         mddev->bitmap = bitmap;
1489
1490         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1491
1492         return bitmap_update_sb(bitmap);
1493
1494  error:
1495         bitmap_free(bitmap);
1496         return err;
1497 }
1498
1499 /* the bitmap API -- for raid personalities */
1500 EXPORT_SYMBOL(bitmap_startwrite);
1501 EXPORT_SYMBOL(bitmap_endwrite);
1502 EXPORT_SYMBOL(bitmap_start_sync);
1503 EXPORT_SYMBOL(bitmap_end_sync);
1504 EXPORT_SYMBOL(bitmap_unplug);
1505 EXPORT_SYMBOL(bitmap_close_sync);