Remove do_sync_file_range()
[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         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_path.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                 loff_t isize = i_size_read(bitmap->file->f_mapping->host);
484                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
485
486                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
487         } else {
488                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
489         }
490         if (IS_ERR(bitmap->sb_page)) {
491                 err = PTR_ERR(bitmap->sb_page);
492                 bitmap->sb_page = NULL;
493                 return err;
494         }
495
496         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
497
498         chunksize = le32_to_cpu(sb->chunksize);
499         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
500         write_behind = le32_to_cpu(sb->write_behind);
501
502         /* verify that the bitmap-specific fields are valid */
503         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
504                 reason = "bad magic";
505         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
506                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
507                 reason = "unrecognized superblock version";
508         else if (chunksize < PAGE_SIZE)
509                 reason = "bitmap chunksize too small";
510         else if ((1 << ffz(~chunksize)) != chunksize)
511                 reason = "bitmap chunksize not a power of 2";
512         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
513                 reason = "daemon sleep period out of range";
514         else if (write_behind > COUNTER_MAX)
515                 reason = "write-behind limit out of range (0 - 16383)";
516         if (reason) {
517                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
518                         bmname(bitmap), reason);
519                 goto out;
520         }
521
522         /* keep the array size field of the bitmap superblock up to date */
523         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
524
525         if (!bitmap->mddev->persistent)
526                 goto success;
527
528         /*
529          * if we have a persistent array superblock, compare the
530          * bitmap's UUID and event counter to the mddev's
531          */
532         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
533                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
534                         bmname(bitmap));
535                 goto out;
536         }
537         events = le64_to_cpu(sb->events);
538         if (events < bitmap->mddev->events) {
539                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
540                         "-- forcing full recovery\n", bmname(bitmap), events,
541                         (unsigned long long) bitmap->mddev->events);
542                 sb->state |= cpu_to_le32(BITMAP_STALE);
543         }
544 success:
545         /* assign fields using values from superblock */
546         bitmap->chunksize = chunksize;
547         bitmap->daemon_sleep = daemon_sleep;
548         bitmap->daemon_lastrun = jiffies;
549         bitmap->max_write_behind = write_behind;
550         bitmap->flags |= le32_to_cpu(sb->state);
551         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
552                 bitmap->flags |= BITMAP_HOSTENDIAN;
553         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
554         if (sb->state & cpu_to_le32(BITMAP_STALE))
555                 bitmap->events_cleared = bitmap->mddev->events;
556         err = 0;
557 out:
558         kunmap_atomic(sb, KM_USER0);
559         if (err)
560                 bitmap_print_sb(bitmap);
561         return err;
562 }
563
564 enum bitmap_mask_op {
565         MASK_SET,
566         MASK_UNSET
567 };
568
569 /* record the state of the bitmap in the superblock */
570 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
571                                 enum bitmap_mask_op op)
572 {
573         bitmap_super_t *sb;
574         unsigned long flags;
575
576         spin_lock_irqsave(&bitmap->lock, flags);
577         if (!bitmap->sb_page) { /* can't set the state */
578                 spin_unlock_irqrestore(&bitmap->lock, flags);
579                 return;
580         }
581         spin_unlock_irqrestore(&bitmap->lock, flags);
582         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
583         switch (op) {
584                 case MASK_SET: sb->state |= cpu_to_le32(bits);
585                                 break;
586                 case MASK_UNSET: sb->state &= cpu_to_le32(~bits);
587                                 break;
588                 default: BUG();
589         }
590         kunmap_atomic(sb, KM_USER0);
591 }
592
593 /*
594  * general bitmap file operations
595  */
596
597 /* calculate the index of the page that contains this bit */
598 static inline unsigned long file_page_index(unsigned long chunk)
599 {
600         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
601 }
602
603 /* calculate the (bit) offset of this bit within a page */
604 static inline unsigned long file_page_offset(unsigned long chunk)
605 {
606         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
607 }
608
609 /*
610  * return a pointer to the page in the filemap that contains the given bit
611  *
612  * this lookup is complicated by the fact that the bitmap sb might be exactly
613  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
614  * 0 or page 1
615  */
616 static inline struct page *filemap_get_page(struct bitmap *bitmap,
617                                         unsigned long chunk)
618 {
619         if (file_page_index(chunk) >= bitmap->file_pages) return NULL;
620         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
621 }
622
623
624 static void bitmap_file_unmap(struct bitmap *bitmap)
625 {
626         struct page **map, *sb_page;
627         unsigned long *attr;
628         int pages;
629         unsigned long flags;
630
631         spin_lock_irqsave(&bitmap->lock, flags);
632         map = bitmap->filemap;
633         bitmap->filemap = NULL;
634         attr = bitmap->filemap_attr;
635         bitmap->filemap_attr = NULL;
636         pages = bitmap->file_pages;
637         bitmap->file_pages = 0;
638         sb_page = bitmap->sb_page;
639         bitmap->sb_page = NULL;
640         spin_unlock_irqrestore(&bitmap->lock, flags);
641
642         while (pages--)
643                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
644                         free_buffers(map[pages]);
645         kfree(map);
646         kfree(attr);
647
648         if (sb_page)
649                 free_buffers(sb_page);
650 }
651
652 static void bitmap_file_put(struct bitmap *bitmap)
653 {
654         struct file *file;
655         unsigned long flags;
656
657         spin_lock_irqsave(&bitmap->lock, flags);
658         file = bitmap->file;
659         bitmap->file = NULL;
660         spin_unlock_irqrestore(&bitmap->lock, flags);
661
662         if (file)
663                 wait_event(bitmap->write_wait,
664                            atomic_read(&bitmap->pending_writes)==0);
665         bitmap_file_unmap(bitmap);
666
667         if (file) {
668                 struct inode *inode = file->f_path.dentry->d_inode;
669                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
670                 fput(file);
671         }
672 }
673
674
675 /*
676  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
677  * then it is no longer reliable, so we stop using it and we mark the file
678  * as failed in the superblock
679  */
680 static void bitmap_file_kick(struct bitmap *bitmap)
681 {
682         char *path, *ptr = NULL;
683
684         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
685         bitmap_update_sb(bitmap);
686
687         if (bitmap->file) {
688                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
689                 if (path)
690                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
691
692                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
693                        bmname(bitmap), ptr ? ptr : "");
694
695                 kfree(path);
696         }
697
698         bitmap_file_put(bitmap);
699
700         return;
701 }
702
703 enum bitmap_page_attr {
704         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
705         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
706         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
707 };
708
709 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
710                                 enum bitmap_page_attr attr)
711 {
712         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
713 }
714
715 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
716                                 enum bitmap_page_attr attr)
717 {
718         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
719 }
720
721 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
722                                            enum bitmap_page_attr attr)
723 {
724         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
725 }
726
727 /*
728  * bitmap_file_set_bit -- called before performing a write to the md device
729  * to set (and eventually sync) a particular bit in the bitmap file
730  *
731  * we set the bit immediately, then we record the page number so that
732  * when an unplug occurs, we can flush the dirty pages out to disk
733  */
734 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
735 {
736         unsigned long bit;
737         struct page *page;
738         void *kaddr;
739         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
740
741         if (!bitmap->filemap) {
742                 return;
743         }
744
745         page = filemap_get_page(bitmap, chunk);
746         if (!page) return;
747         bit = file_page_offset(chunk);
748
749         /* set the bit */
750         kaddr = kmap_atomic(page, KM_USER0);
751         if (bitmap->flags & BITMAP_HOSTENDIAN)
752                 set_bit(bit, kaddr);
753         else
754                 ext2_set_bit(bit, kaddr);
755         kunmap_atomic(kaddr, KM_USER0);
756         PRINTK("set file bit %lu page %lu\n", bit, page->index);
757
758         /* record page number so it gets flushed to disk when unplug occurs */
759         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
760
761 }
762
763 /* this gets called when the md device is ready to unplug its underlying
764  * (slave) device queues -- before we let any writes go down, we need to
765  * sync the dirty pages of the bitmap file to disk */
766 int bitmap_unplug(struct bitmap *bitmap)
767 {
768         unsigned long i, flags;
769         int dirty, need_write;
770         struct page *page;
771         int wait = 0;
772         int err;
773
774         if (!bitmap)
775                 return 0;
776
777         /* look at each page to see if there are any set bits that need to be
778          * flushed out to disk */
779         for (i = 0; i < bitmap->file_pages; i++) {
780                 spin_lock_irqsave(&bitmap->lock, flags);
781                 if (!bitmap->filemap) {
782                         spin_unlock_irqrestore(&bitmap->lock, flags);
783                         return 0;
784                 }
785                 page = bitmap->filemap[i];
786                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
787                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
788                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
789                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
790                 if (dirty)
791                         wait = 1;
792                 spin_unlock_irqrestore(&bitmap->lock, flags);
793
794                 if (dirty | need_write)
795                         err = write_page(bitmap, page, 0);
796         }
797         if (wait) { /* if any writes were performed, we need to wait on them */
798                 if (bitmap->file)
799                         wait_event(bitmap->write_wait,
800                                    atomic_read(&bitmap->pending_writes)==0);
801                 else
802                         md_super_wait(bitmap->mddev);
803         }
804         if (bitmap->flags & BITMAP_WRITE_ERROR)
805                 bitmap_file_kick(bitmap);
806         return 0;
807 }
808
809 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
810 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
811  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
812  * memory mapping of the bitmap file
813  * Special cases:
814  *   if there's no bitmap file, or if the bitmap file had been
815  *   previously kicked from the array, we mark all the bits as
816  *   1's in order to cause a full resync.
817  *
818  * We ignore all bits for sectors that end earlier than 'start'.
819  * This is used when reading an out-of-date bitmap...
820  */
821 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
822 {
823         unsigned long i, chunks, index, oldindex, bit;
824         struct page *page = NULL, *oldpage = NULL;
825         unsigned long num_pages, bit_cnt = 0;
826         struct file *file;
827         unsigned long bytes, offset;
828         int outofdate;
829         int ret = -ENOSPC;
830         void *paddr;
831
832         chunks = bitmap->chunks;
833         file = bitmap->file;
834
835         BUG_ON(!file && !bitmap->offset);
836
837 #ifdef INJECT_FAULTS_3
838         outofdate = 1;
839 #else
840         outofdate = bitmap->flags & BITMAP_STALE;
841 #endif
842         if (outofdate)
843                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
844                         "recovery\n", bmname(bitmap));
845
846         bytes = (chunks + 7) / 8;
847
848         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
849
850         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
851                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
852                         bmname(bitmap),
853                         (unsigned long) i_size_read(file->f_mapping->host),
854                         bytes + sizeof(bitmap_super_t));
855                 goto out;
856         }
857
858         ret = -ENOMEM;
859
860         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
861         if (!bitmap->filemap)
862                 goto out;
863
864         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
865         bitmap->filemap_attr = kzalloc(
866                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
867                 GFP_KERNEL);
868         if (!bitmap->filemap_attr)
869                 goto out;
870
871         oldindex = ~0L;
872
873         for (i = 0; i < chunks; i++) {
874                 int b;
875                 index = file_page_index(i);
876                 bit = file_page_offset(i);
877                 if (index != oldindex) { /* this is a new page, read it in */
878                         int count;
879                         /* unmap the old page, we're done with it */
880                         if (index == num_pages-1)
881                                 count = bytes + sizeof(bitmap_super_t)
882                                         - index * PAGE_SIZE;
883                         else
884                                 count = PAGE_SIZE;
885                         if (index == 0) {
886                                 /*
887                                  * if we're here then the superblock page
888                                  * contains some bits (PAGE_SIZE != sizeof sb)
889                                  * we've already read it in, so just use it
890                                  */
891                                 page = bitmap->sb_page;
892                                 offset = sizeof(bitmap_super_t);
893                         } else if (file) {
894                                 page = read_page(file, index, bitmap, count);
895                                 offset = 0;
896                         } else {
897                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
898                                 offset = 0;
899                         }
900                         if (IS_ERR(page)) { /* read error */
901                                 ret = PTR_ERR(page);
902                                 goto out;
903                         }
904
905                         oldindex = index;
906                         oldpage = page;
907
908                         if (outofdate) {
909                                 /*
910                                  * if bitmap is out of date, dirty the
911                                  * whole page and write it out
912                                  */
913                                 paddr = kmap_atomic(page, KM_USER0);
914                                 memset(paddr + offset, 0xff,
915                                        PAGE_SIZE - offset);
916                                 kunmap_atomic(paddr, KM_USER0);
917                                 ret = write_page(bitmap, page, 1);
918                                 if (ret) {
919                                         /* release, page not in filemap yet */
920                                         put_page(page);
921                                         goto out;
922                                 }
923                         }
924
925                         bitmap->filemap[bitmap->file_pages++] = page;
926                 }
927                 paddr = kmap_atomic(page, KM_USER0);
928                 if (bitmap->flags & BITMAP_HOSTENDIAN)
929                         b = test_bit(bit, paddr);
930                 else
931                         b = ext2_test_bit(bit, paddr);
932                 kunmap_atomic(paddr, KM_USER0);
933                 if (b) {
934                         /* if the disk bit is set, set the memory bit */
935                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
936                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
937                                 );
938                         bit_cnt++;
939                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
940                 }
941         }
942
943         /* everything went OK */
944         ret = 0;
945         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
946
947         if (bit_cnt) { /* Kick recovery if any bits were set */
948                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
949                 md_wakeup_thread(bitmap->mddev->thread);
950         }
951
952 out:
953         printk(KERN_INFO "%s: bitmap initialized from disk: "
954                 "read %lu/%lu pages, set %lu bits, status: %d\n",
955                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
956
957         return ret;
958 }
959
960 void bitmap_write_all(struct bitmap *bitmap)
961 {
962         /* We don't actually write all bitmap blocks here,
963          * just flag them as needing to be written
964          */
965         int i;
966
967         for (i=0; i < bitmap->file_pages; i++)
968                 set_page_attr(bitmap, bitmap->filemap[i],
969                               BITMAP_PAGE_NEEDWRITE);
970 }
971
972
973 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
974 {
975         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
976         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
977         bitmap->bp[page].count += inc;
978 /*
979         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
980                               (unsigned long long)offset, inc, bitmap->bp[page].count);
981 */
982         bitmap_checkfree(bitmap, page);
983 }
984 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
985                                             sector_t offset, int *blocks,
986                                             int create);
987
988 /*
989  * bitmap daemon -- periodically wakes up to clean bits and flush pages
990  *                      out to disk
991  */
992
993 int bitmap_daemon_work(struct bitmap *bitmap)
994 {
995         unsigned long j;
996         unsigned long flags;
997         struct page *page = NULL, *lastpage = NULL;
998         int err = 0;
999         int blocks;
1000         void *paddr;
1001
1002         if (bitmap == NULL)
1003                 return 0;
1004         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1005                 return 0;
1006         bitmap->daemon_lastrun = jiffies;
1007
1008         for (j = 0; j < bitmap->chunks; j++) {
1009                 bitmap_counter_t *bmc;
1010                 spin_lock_irqsave(&bitmap->lock, flags);
1011                 if (!bitmap->filemap) {
1012                         /* error or shutdown */
1013                         spin_unlock_irqrestore(&bitmap->lock, flags);
1014                         break;
1015                 }
1016
1017                 page = filemap_get_page(bitmap, j);
1018
1019                 if (page != lastpage) {
1020                         /* skip this page unless it's marked as needing cleaning */
1021                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1022                                 int need_write = test_page_attr(bitmap, page,
1023                                                                 BITMAP_PAGE_NEEDWRITE);
1024                                 if (need_write)
1025                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1026
1027                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1028                                 if (need_write) {
1029                                         switch (write_page(bitmap, page, 0)) {
1030                                         case 0:
1031                                                 break;
1032                                         default:
1033                                                 bitmap_file_kick(bitmap);
1034                                         }
1035                                 }
1036                                 continue;
1037                         }
1038
1039                         /* grab the new page, sync and release the old */
1040                         if (lastpage != NULL) {
1041                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1042                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1043                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1044                                         err = write_page(bitmap, lastpage, 0);
1045                                 } else {
1046                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1047                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1048                                 }
1049                                 if (err)
1050                                         bitmap_file_kick(bitmap);
1051                         } else
1052                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1053                         lastpage = page;
1054 /*
1055                         printk("bitmap clean at page %lu\n", j);
1056 */
1057                         spin_lock_irqsave(&bitmap->lock, flags);
1058                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1059                 }
1060                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1061                                         &blocks, 0);
1062                 if (bmc) {
1063 /*
1064   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1065 */
1066                         if (*bmc == 2) {
1067                                 *bmc=1; /* maybe clear the bit next time */
1068                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1069                         } else if (*bmc == 1) {
1070                                 /* we can clear the bit */
1071                                 *bmc = 0;
1072                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1073                                                   -1);
1074
1075                                 /* clear the bit */
1076                                 paddr = kmap_atomic(page, KM_USER0);
1077                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1078                                         clear_bit(file_page_offset(j), paddr);
1079                                 else
1080                                         ext2_clear_bit(file_page_offset(j), paddr);
1081                                 kunmap_atomic(paddr, KM_USER0);
1082                         }
1083                 }
1084                 spin_unlock_irqrestore(&bitmap->lock, flags);
1085         }
1086
1087         /* now sync the final page */
1088         if (lastpage != NULL) {
1089                 spin_lock_irqsave(&bitmap->lock, flags);
1090                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1091                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1092                         spin_unlock_irqrestore(&bitmap->lock, flags);
1093                         err = write_page(bitmap, lastpage, 0);
1094                 } else {
1095                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1096                         spin_unlock_irqrestore(&bitmap->lock, flags);
1097                 }
1098         }
1099
1100         return err;
1101 }
1102
1103 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1104                                             sector_t offset, int *blocks,
1105                                             int create)
1106 {
1107         /* If 'create', we might release the lock and reclaim it.
1108          * The lock must have been taken with interrupts enabled.
1109          * If !create, we don't release the lock.
1110          */
1111         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1112         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1113         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1114         sector_t csize;
1115
1116         if (bitmap_checkpage(bitmap, page, create) < 0) {
1117                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1118                 *blocks = csize - (offset & (csize- 1));
1119                 return NULL;
1120         }
1121         /* now locked ... */
1122
1123         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1124                 /* should we use the first or second counter field
1125                  * of the hijacked pointer? */
1126                 int hi = (pageoff > PAGE_COUNTER_MASK);
1127                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1128                                           PAGE_COUNTER_SHIFT - 1);
1129                 *blocks = csize - (offset & (csize- 1));
1130                 return  &((bitmap_counter_t *)
1131                           &bitmap->bp[page].map)[hi];
1132         } else { /* page is allocated */
1133                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1134                 *blocks = csize - (offset & (csize- 1));
1135                 return (bitmap_counter_t *)
1136                         &(bitmap->bp[page].map[pageoff]);
1137         }
1138 }
1139
1140 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1141 {
1142         if (!bitmap) return 0;
1143
1144         if (behind) {
1145                 atomic_inc(&bitmap->behind_writes);
1146                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1147                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1148         }
1149
1150         while (sectors) {
1151                 int blocks;
1152                 bitmap_counter_t *bmc;
1153
1154                 spin_lock_irq(&bitmap->lock);
1155                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1156                 if (!bmc) {
1157                         spin_unlock_irq(&bitmap->lock);
1158                         return 0;
1159                 }
1160
1161                 if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
1162                         DEFINE_WAIT(__wait);
1163                         /* note that it is safe to do the prepare_to_wait
1164                          * after the test as long as we do it before dropping
1165                          * the spinlock.
1166                          */
1167                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1168                                         TASK_UNINTERRUPTIBLE);
1169                         spin_unlock_irq(&bitmap->lock);
1170                         bitmap->mddev->queue
1171                                 ->unplug_fn(bitmap->mddev->queue);
1172                         schedule();
1173                         finish_wait(&bitmap->overflow_wait, &__wait);
1174                         continue;
1175                 }
1176
1177                 switch(*bmc) {
1178                 case 0:
1179                         bitmap_file_set_bit(bitmap, offset);
1180                         bitmap_count_page(bitmap,offset, 1);
1181                         blk_plug_device(bitmap->mddev->queue);
1182                         /* fall through */
1183                 case 1:
1184                         *bmc = 2;
1185                 }
1186
1187                 (*bmc)++;
1188
1189                 spin_unlock_irq(&bitmap->lock);
1190
1191                 offset += blocks;
1192                 if (sectors > blocks)
1193                         sectors -= blocks;
1194                 else sectors = 0;
1195         }
1196         return 0;
1197 }
1198
1199 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1200                      int success, int behind)
1201 {
1202         if (!bitmap) return;
1203         if (behind) {
1204                 atomic_dec(&bitmap->behind_writes);
1205                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1206                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1207         }
1208
1209         while (sectors) {
1210                 int blocks;
1211                 unsigned long flags;
1212                 bitmap_counter_t *bmc;
1213
1214                 spin_lock_irqsave(&bitmap->lock, flags);
1215                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1216                 if (!bmc) {
1217                         spin_unlock_irqrestore(&bitmap->lock, flags);
1218                         return;
1219                 }
1220
1221                 if (!success && ! (*bmc & NEEDED_MASK))
1222                         *bmc |= NEEDED_MASK;
1223
1224                 if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
1225                         wake_up(&bitmap->overflow_wait);
1226
1227                 (*bmc)--;
1228                 if (*bmc <= 2) {
1229                         set_page_attr(bitmap,
1230                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1231                                       BITMAP_PAGE_CLEAN);
1232                 }
1233                 spin_unlock_irqrestore(&bitmap->lock, flags);
1234                 offset += blocks;
1235                 if (sectors > blocks)
1236                         sectors -= blocks;
1237                 else sectors = 0;
1238         }
1239 }
1240
1241 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1242                         int degraded)
1243 {
1244         bitmap_counter_t *bmc;
1245         int rv;
1246         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1247                 *blocks = 1024;
1248                 return 1; /* always resync if no bitmap */
1249         }
1250         spin_lock_irq(&bitmap->lock);
1251         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1252         rv = 0;
1253         if (bmc) {
1254                 /* locked */
1255                 if (RESYNC(*bmc))
1256                         rv = 1;
1257                 else if (NEEDED(*bmc)) {
1258                         rv = 1;
1259                         if (!degraded) { /* don't set/clear bits if degraded */
1260                                 *bmc |= RESYNC_MASK;
1261                                 *bmc &= ~NEEDED_MASK;
1262                         }
1263                 }
1264         }
1265         spin_unlock_irq(&bitmap->lock);
1266         return rv;
1267 }
1268
1269 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1270 {
1271         bitmap_counter_t *bmc;
1272         unsigned long flags;
1273 /*
1274         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1275 */      if (bitmap == NULL) {
1276                 *blocks = 1024;
1277                 return;
1278         }
1279         spin_lock_irqsave(&bitmap->lock, flags);
1280         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1281         if (bmc == NULL)
1282                 goto unlock;
1283         /* locked */
1284 /*
1285         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1286 */
1287         if (RESYNC(*bmc)) {
1288                 *bmc &= ~RESYNC_MASK;
1289
1290                 if (!NEEDED(*bmc) && aborted)
1291                         *bmc |= NEEDED_MASK;
1292                 else {
1293                         if (*bmc <= 2) {
1294                                 set_page_attr(bitmap,
1295                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1296                                               BITMAP_PAGE_CLEAN);
1297                         }
1298                 }
1299         }
1300  unlock:
1301         spin_unlock_irqrestore(&bitmap->lock, flags);
1302 }
1303
1304 void bitmap_close_sync(struct bitmap *bitmap)
1305 {
1306         /* Sync has finished, and any bitmap chunks that weren't synced
1307          * properly have been aborted.  It remains to us to clear the
1308          * RESYNC bit wherever it is still on
1309          */
1310         sector_t sector = 0;
1311         int blocks;
1312         if (!bitmap) return;
1313         while (sector < bitmap->mddev->resync_max_sectors) {
1314                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1315 /*
1316                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1317                                          (unsigned long long)sector, blocks);
1318 */              sector += blocks;
1319         }
1320 }
1321
1322 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1323 {
1324         /* For each chunk covered by any of these sectors, set the
1325          * counter to 1 and set resync_needed.  They should all
1326          * be 0 at this point
1327          */
1328
1329         int secs;
1330         bitmap_counter_t *bmc;
1331         spin_lock_irq(&bitmap->lock);
1332         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1333         if (!bmc) {
1334                 spin_unlock_irq(&bitmap->lock);
1335                 return;
1336         }
1337         if (! *bmc) {
1338                 struct page *page;
1339                 *bmc = 1 | (needed?NEEDED_MASK:0);
1340                 bitmap_count_page(bitmap, offset, 1);
1341                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1342                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1343         }
1344         spin_unlock_irq(&bitmap->lock);
1345
1346 }
1347
1348 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1349 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1350 {
1351         unsigned long chunk;
1352
1353         for (chunk = s; chunk <= e; chunk++) {
1354                 sector_t sec = chunk << CHUNK_BLOCK_SHIFT(bitmap);
1355                 bitmap_set_memory_bits(bitmap, sec, 1);
1356                 bitmap_file_set_bit(bitmap, sec);
1357         }
1358 }
1359
1360 /*
1361  * flush out any pending updates
1362  */
1363 void bitmap_flush(mddev_t *mddev)
1364 {
1365         struct bitmap *bitmap = mddev->bitmap;
1366         int sleep;
1367
1368         if (!bitmap) /* there was no bitmap */
1369                 return;
1370
1371         /* run the daemon_work three time to ensure everything is flushed
1372          * that can be
1373          */
1374         sleep = bitmap->daemon_sleep;
1375         bitmap->daemon_sleep = 0;
1376         bitmap_daemon_work(bitmap);
1377         bitmap_daemon_work(bitmap);
1378         bitmap_daemon_work(bitmap);
1379         bitmap->daemon_sleep = sleep;
1380         bitmap_update_sb(bitmap);
1381 }
1382
1383 /*
1384  * free memory that was allocated
1385  */
1386 static void bitmap_free(struct bitmap *bitmap)
1387 {
1388         unsigned long k, pages;
1389         struct bitmap_page *bp;
1390
1391         if (!bitmap) /* there was no bitmap */
1392                 return;
1393
1394         /* release the bitmap file and kill the daemon */
1395         bitmap_file_put(bitmap);
1396
1397         bp = bitmap->bp;
1398         pages = bitmap->pages;
1399
1400         /* free all allocated memory */
1401
1402         if (bp) /* deallocate the page memory */
1403                 for (k = 0; k < pages; k++)
1404                         if (bp[k].map && !bp[k].hijacked)
1405                                 kfree(bp[k].map);
1406         kfree(bp);
1407         kfree(bitmap);
1408 }
1409 void bitmap_destroy(mddev_t *mddev)
1410 {
1411         struct bitmap *bitmap = mddev->bitmap;
1412
1413         if (!bitmap) /* there was no bitmap */
1414                 return;
1415
1416         mddev->bitmap = NULL; /* disconnect from the md device */
1417         if (mddev->thread)
1418                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1419
1420         bitmap_free(bitmap);
1421 }
1422
1423 /*
1424  * initialize the bitmap structure
1425  * if this returns an error, bitmap_destroy must be called to do clean up
1426  */
1427 int bitmap_create(mddev_t *mddev)
1428 {
1429         struct bitmap *bitmap;
1430         unsigned long blocks = mddev->resync_max_sectors;
1431         unsigned long chunks;
1432         unsigned long pages;
1433         struct file *file = mddev->bitmap_file;
1434         int err;
1435         sector_t start;
1436
1437         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1438
1439         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1440                 return 0;
1441
1442         BUG_ON(file && mddev->bitmap_offset);
1443
1444         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1445         if (!bitmap)
1446                 return -ENOMEM;
1447
1448         spin_lock_init(&bitmap->lock);
1449         atomic_set(&bitmap->pending_writes, 0);
1450         init_waitqueue_head(&bitmap->write_wait);
1451         init_waitqueue_head(&bitmap->overflow_wait);
1452
1453         bitmap->mddev = mddev;
1454
1455         bitmap->file = file;
1456         bitmap->offset = mddev->bitmap_offset;
1457         if (file) {
1458                 get_file(file);
1459                 do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
1460                                       SYNC_FILE_RANGE_WAIT_BEFORE |
1461                                       SYNC_FILE_RANGE_WRITE |
1462                                       SYNC_FILE_RANGE_WAIT_AFTER);
1463         }
1464         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1465         err = bitmap_read_sb(bitmap);
1466         if (err)
1467                 goto error;
1468
1469         bitmap->chunkshift = ffz(~bitmap->chunksize);
1470
1471         /* now that chunksize and chunkshift are set, we can use these macros */
1472         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1473                         CHUNK_BLOCK_RATIO(bitmap);
1474         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1475
1476         BUG_ON(!pages);
1477
1478         bitmap->chunks = chunks;
1479         bitmap->pages = pages;
1480         bitmap->missing_pages = pages;
1481         bitmap->counter_bits = COUNTER_BITS;
1482
1483         bitmap->syncchunk = ~0UL;
1484
1485 #ifdef INJECT_FATAL_FAULT_1
1486         bitmap->bp = NULL;
1487 #else
1488         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1489 #endif
1490         err = -ENOMEM;
1491         if (!bitmap->bp)
1492                 goto error;
1493
1494         /* now that we have some pages available, initialize the in-memory
1495          * bitmap from the on-disk bitmap */
1496         start = 0;
1497         if (mddev->degraded == 0
1498             || bitmap->events_cleared == mddev->events)
1499                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1500                 start = mddev->recovery_cp;
1501         err = bitmap_init_from_disk(bitmap, start);
1502
1503         if (err)
1504                 goto error;
1505
1506         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1507                 pages, bmname(bitmap));
1508
1509         mddev->bitmap = bitmap;
1510
1511         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1512
1513         return bitmap_update_sb(bitmap);
1514
1515  error:
1516         bitmap_free(bitmap);
1517         return err;
1518 }
1519
1520 /* the bitmap API -- for raid personalities */
1521 EXPORT_SYMBOL(bitmap_startwrite);
1522 EXPORT_SYMBOL(bitmap_endwrite);
1523 EXPORT_SYMBOL(bitmap_start_sync);
1524 EXPORT_SYMBOL(bitmap_end_sync);
1525 EXPORT_SYMBOL(bitmap_unplug);
1526 EXPORT_SYMBOL(bitmap_close_sync);