md/bitmap: clear BITMAP_WRITE_ERROR bit before writing it to sb
[sfrench/cifs-2.6.git] / drivers / md / 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  */
17
18 #include <linux/blkdev.h>
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/seq_file.h>
30 #include <trace/events/block.h>
31 #include "md.h"
32 #include "md-bitmap.h"
33
34 static inline char *bmname(struct bitmap *bitmap)
35 {
36         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
37 }
38
39 /*
40  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
41  *
42  * 1) check to see if this page is allocated, if it's not then try to alloc
43  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
44  *    page pointer directly as a counter
45  *
46  * if we find our page, we increment the page's refcount so that it stays
47  * allocated while we're using it
48  */
49 static int bitmap_checkpage(struct bitmap_counts *bitmap,
50                             unsigned long page, int create, int no_hijack)
51 __releases(bitmap->lock)
52 __acquires(bitmap->lock)
53 {
54         unsigned char *mappage;
55
56         if (page >= bitmap->pages) {
57                 /* This can happen if bitmap_start_sync goes beyond
58                  * End-of-device while looking for a whole page.
59                  * It is harmless.
60                  */
61                 return -EINVAL;
62         }
63
64         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
65                 return 0;
66
67         if (bitmap->bp[page].map) /* page is already allocated, just return */
68                 return 0;
69
70         if (!create)
71                 return -ENOENT;
72
73         /* this page has not been allocated yet */
74
75         spin_unlock_irq(&bitmap->lock);
76         /* It is possible that this is being called inside a
77          * prepare_to_wait/finish_wait loop from raid5c:make_request().
78          * In general it is not permitted to sleep in that context as it
79          * can cause the loop to spin freely.
80          * That doesn't apply here as we can only reach this point
81          * once with any loop.
82          * When this function completes, either bp[page].map or
83          * bp[page].hijacked.  In either case, this function will
84          * abort before getting to this point again.  So there is
85          * no risk of a free-spin, and so it is safe to assert
86          * that sleeping here is allowed.
87          */
88         sched_annotate_sleep();
89         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
90         spin_lock_irq(&bitmap->lock);
91
92         if (mappage == NULL) {
93                 pr_debug("md/bitmap: map page allocation failed, hijacking\n");
94                 /* We don't support hijack for cluster raid */
95                 if (no_hijack)
96                         return -ENOMEM;
97                 /* failed - set the hijacked flag so that we can use the
98                  * pointer as a counter */
99                 if (!bitmap->bp[page].map)
100                         bitmap->bp[page].hijacked = 1;
101         } else if (bitmap->bp[page].map ||
102                    bitmap->bp[page].hijacked) {
103                 /* somebody beat us to getting the page */
104                 kfree(mappage);
105         } else {
106
107                 /* no page was in place and we have one, so install it */
108
109                 bitmap->bp[page].map = mappage;
110                 bitmap->missing_pages--;
111         }
112         return 0;
113 }
114
115 /* if page is completely empty, put it back on the free list, or dealloc it */
116 /* if page was hijacked, unmark the flag so it might get alloced next time */
117 /* Note: lock should be held when calling this */
118 static void bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
119 {
120         char *ptr;
121
122         if (bitmap->bp[page].count) /* page is still busy */
123                 return;
124
125         /* page is no longer in use, it can be released */
126
127         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
128                 bitmap->bp[page].hijacked = 0;
129                 bitmap->bp[page].map = NULL;
130         } else {
131                 /* normal case, free the page */
132                 ptr = bitmap->bp[page].map;
133                 bitmap->bp[page].map = NULL;
134                 bitmap->missing_pages++;
135                 kfree(ptr);
136         }
137 }
138
139 /*
140  * bitmap file handling - read and write the bitmap file and its superblock
141  */
142
143 /*
144  * basic page I/O operations
145  */
146
147 /* IO operations when bitmap is stored near all superblocks */
148 static int read_sb_page(struct mddev *mddev, loff_t offset,
149                         struct page *page,
150                         unsigned long index, int size)
151 {
152         /* choose a good rdev and read the page from there */
153
154         struct md_rdev *rdev;
155         sector_t target;
156
157         rdev_for_each(rdev, mddev) {
158                 if (! test_bit(In_sync, &rdev->flags)
159                     || test_bit(Faulty, &rdev->flags)
160                     || test_bit(Bitmap_sync, &rdev->flags))
161                         continue;
162
163                 target = offset + index * (PAGE_SIZE/512);
164
165                 if (sync_page_io(rdev, target,
166                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
167                                  page, REQ_OP_READ, 0, true)) {
168                         page->index = index;
169                         return 0;
170                 }
171         }
172         return -EIO;
173 }
174
175 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
176 {
177         /* Iterate the disks of an mddev, using rcu to protect access to the
178          * linked list, and raising the refcount of devices we return to ensure
179          * they don't disappear while in use.
180          * As devices are only added or removed when raid_disk is < 0 and
181          * nr_pending is 0 and In_sync is clear, the entries we return will
182          * still be in the same position on the list when we re-enter
183          * list_for_each_entry_continue_rcu.
184          *
185          * Note that if entered with 'rdev == NULL' to start at the
186          * beginning, we temporarily assign 'rdev' to an address which
187          * isn't really an rdev, but which can be used by
188          * list_for_each_entry_continue_rcu() to find the first entry.
189          */
190         rcu_read_lock();
191         if (rdev == NULL)
192                 /* start at the beginning */
193                 rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
194         else {
195                 /* release the previous rdev and start from there. */
196                 rdev_dec_pending(rdev, mddev);
197         }
198         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
199                 if (rdev->raid_disk >= 0 &&
200                     !test_bit(Faulty, &rdev->flags)) {
201                         /* this is a usable devices */
202                         atomic_inc(&rdev->nr_pending);
203                         rcu_read_unlock();
204                         return rdev;
205                 }
206         }
207         rcu_read_unlock();
208         return NULL;
209 }
210
211 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
212 {
213         struct md_rdev *rdev;
214         struct block_device *bdev;
215         struct mddev *mddev = bitmap->mddev;
216         struct bitmap_storage *store = &bitmap->storage;
217
218 restart:
219         rdev = NULL;
220         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
221                 int size = PAGE_SIZE;
222                 loff_t offset = mddev->bitmap_info.offset;
223
224                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
225
226                 if (page->index == store->file_pages-1) {
227                         int last_page_size = store->bytes & (PAGE_SIZE-1);
228                         if (last_page_size == 0)
229                                 last_page_size = PAGE_SIZE;
230                         size = roundup(last_page_size,
231                                        bdev_logical_block_size(bdev));
232                 }
233                 /* Just make sure we aren't corrupting data or
234                  * metadata
235                  */
236                 if (mddev->external) {
237                         /* Bitmap could be anywhere. */
238                         if (rdev->sb_start + offset + (page->index
239                                                        * (PAGE_SIZE/512))
240                             > rdev->data_offset
241                             &&
242                             rdev->sb_start + offset
243                             < (rdev->data_offset + mddev->dev_sectors
244                              + (PAGE_SIZE/512)))
245                                 goto bad_alignment;
246                 } else if (offset < 0) {
247                         /* DATA  BITMAP METADATA  */
248                         if (offset
249                             + (long)(page->index * (PAGE_SIZE/512))
250                             + size/512 > 0)
251                                 /* bitmap runs in to metadata */
252                                 goto bad_alignment;
253                         if (rdev->data_offset + mddev->dev_sectors
254                             > rdev->sb_start + offset)
255                                 /* data runs in to bitmap */
256                                 goto bad_alignment;
257                 } else if (rdev->sb_start < rdev->data_offset) {
258                         /* METADATA BITMAP DATA */
259                         if (rdev->sb_start
260                             + offset
261                             + page->index*(PAGE_SIZE/512) + size/512
262                             > rdev->data_offset)
263                                 /* bitmap runs in to data */
264                                 goto bad_alignment;
265                 } else {
266                         /* DATA METADATA BITMAP - no problems */
267                 }
268                 md_super_write(mddev, rdev,
269                                rdev->sb_start + offset
270                                + page->index * (PAGE_SIZE/512),
271                                size,
272                                page);
273         }
274
275         if (wait && md_super_wait(mddev) < 0)
276                 goto restart;
277         return 0;
278
279  bad_alignment:
280         return -EINVAL;
281 }
282
283 static void bitmap_file_kick(struct bitmap *bitmap);
284 /*
285  * write out a page to a file
286  */
287 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
288 {
289         struct buffer_head *bh;
290
291         if (bitmap->storage.file == NULL) {
292                 switch (write_sb_page(bitmap, page, wait)) {
293                 case -EINVAL:
294                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
295                 }
296         } else {
297
298                 bh = page_buffers(page);
299
300                 while (bh && bh->b_blocknr) {
301                         atomic_inc(&bitmap->pending_writes);
302                         set_buffer_locked(bh);
303                         set_buffer_mapped(bh);
304                         submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
305                         bh = bh->b_this_page;
306                 }
307
308                 if (wait)
309                         wait_event(bitmap->write_wait,
310                                    atomic_read(&bitmap->pending_writes)==0);
311         }
312         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
313                 bitmap_file_kick(bitmap);
314 }
315
316 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
317 {
318         struct bitmap *bitmap = bh->b_private;
319
320         if (!uptodate)
321                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
322         if (atomic_dec_and_test(&bitmap->pending_writes))
323                 wake_up(&bitmap->write_wait);
324 }
325
326 /* copied from buffer.c */
327 static void
328 __clear_page_buffers(struct page *page)
329 {
330         ClearPagePrivate(page);
331         set_page_private(page, 0);
332         put_page(page);
333 }
334 static void free_buffers(struct page *page)
335 {
336         struct buffer_head *bh;
337
338         if (!PagePrivate(page))
339                 return;
340
341         bh = page_buffers(page);
342         while (bh) {
343                 struct buffer_head *next = bh->b_this_page;
344                 free_buffer_head(bh);
345                 bh = next;
346         }
347         __clear_page_buffers(page);
348         put_page(page);
349 }
350
351 /* read a page from a file.
352  * We both read the page, and attach buffers to the page to record the
353  * address of each block (using bmap).  These addresses will be used
354  * to write the block later, completely bypassing the filesystem.
355  * This usage is similar to how swap files are handled, and allows us
356  * to write to a file with no concerns of memory allocation failing.
357  */
358 static int read_page(struct file *file, unsigned long index,
359                      struct bitmap *bitmap,
360                      unsigned long count,
361                      struct page *page)
362 {
363         int ret = 0;
364         struct inode *inode = file_inode(file);
365         struct buffer_head *bh;
366         sector_t block;
367
368         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
369                  (unsigned long long)index << PAGE_SHIFT);
370
371         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
372         if (!bh) {
373                 ret = -ENOMEM;
374                 goto out;
375         }
376         attach_page_buffers(page, bh);
377         block = index << (PAGE_SHIFT - inode->i_blkbits);
378         while (bh) {
379                 if (count == 0)
380                         bh->b_blocknr = 0;
381                 else {
382                         bh->b_blocknr = bmap(inode, block);
383                         if (bh->b_blocknr == 0) {
384                                 /* Cannot use this file! */
385                                 ret = -EINVAL;
386                                 goto out;
387                         }
388                         bh->b_bdev = inode->i_sb->s_bdev;
389                         if (count < (1<<inode->i_blkbits))
390                                 count = 0;
391                         else
392                                 count -= (1<<inode->i_blkbits);
393
394                         bh->b_end_io = end_bitmap_write;
395                         bh->b_private = bitmap;
396                         atomic_inc(&bitmap->pending_writes);
397                         set_buffer_locked(bh);
398                         set_buffer_mapped(bh);
399                         submit_bh(REQ_OP_READ, 0, bh);
400                 }
401                 block++;
402                 bh = bh->b_this_page;
403         }
404         page->index = index;
405
406         wait_event(bitmap->write_wait,
407                    atomic_read(&bitmap->pending_writes)==0);
408         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
409                 ret = -EIO;
410 out:
411         if (ret)
412                 pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
413                        (int)PAGE_SIZE,
414                        (unsigned long long)index << PAGE_SHIFT,
415                        ret);
416         return ret;
417 }
418
419 /*
420  * bitmap file superblock operations
421  */
422
423 /*
424  * bitmap_wait_writes() should be called before writing any bitmap
425  * blocks, to ensure previous writes, particularly from
426  * bitmap_daemon_work(), have completed.
427  */
428 static void bitmap_wait_writes(struct bitmap *bitmap)
429 {
430         if (bitmap->storage.file)
431                 wait_event(bitmap->write_wait,
432                            atomic_read(&bitmap->pending_writes)==0);
433         else
434                 /* Note that we ignore the return value.  The writes
435                  * might have failed, but that would just mean that
436                  * some bits which should be cleared haven't been,
437                  * which is safe.  The relevant bitmap blocks will
438                  * probably get written again, but there is no great
439                  * loss if they aren't.
440                  */
441                 md_super_wait(bitmap->mddev);
442 }
443
444
445 /* update the event counter and sync the superblock to disk */
446 void bitmap_update_sb(struct bitmap *bitmap)
447 {
448         bitmap_super_t *sb;
449
450         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
451                 return;
452         if (bitmap->mddev->bitmap_info.external)
453                 return;
454         if (!bitmap->storage.sb_page) /* no superblock */
455                 return;
456         sb = kmap_atomic(bitmap->storage.sb_page);
457         sb->events = cpu_to_le64(bitmap->mddev->events);
458         if (bitmap->mddev->events < bitmap->events_cleared)
459                 /* rocking back to read-only */
460                 bitmap->events_cleared = bitmap->mddev->events;
461         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
462         /*
463          * clear BITMAP_WRITE_ERROR bit to protect against the case that
464          * a bitmap write error occurred but the later writes succeeded.
465          */
466         sb->state = cpu_to_le32(bitmap->flags & ~BIT(BITMAP_WRITE_ERROR));
467         /* Just in case these have been changed via sysfs: */
468         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
469         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
470         /* This might have been changed by a reshape */
471         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
472         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
473         sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
474         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
475                                            bitmap_info.space);
476         kunmap_atomic(sb);
477         write_page(bitmap, bitmap->storage.sb_page, 1);
478 }
479 EXPORT_SYMBOL(bitmap_update_sb);
480
481 /* print out the bitmap file superblock */
482 void bitmap_print_sb(struct bitmap *bitmap)
483 {
484         bitmap_super_t *sb;
485
486         if (!bitmap || !bitmap->storage.sb_page)
487                 return;
488         sb = kmap_atomic(bitmap->storage.sb_page);
489         pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
490         pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
491         pr_debug("       version: %d\n", le32_to_cpu(sb->version));
492         pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
493                  le32_to_cpu(*(__u32 *)(sb->uuid+0)),
494                  le32_to_cpu(*(__u32 *)(sb->uuid+4)),
495                  le32_to_cpu(*(__u32 *)(sb->uuid+8)),
496                  le32_to_cpu(*(__u32 *)(sb->uuid+12)));
497         pr_debug("        events: %llu\n",
498                  (unsigned long long) le64_to_cpu(sb->events));
499         pr_debug("events cleared: %llu\n",
500                  (unsigned long long) le64_to_cpu(sb->events_cleared));
501         pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
502         pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
503         pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
504         pr_debug("     sync size: %llu KB\n",
505                  (unsigned long long)le64_to_cpu(sb->sync_size)/2);
506         pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
507         kunmap_atomic(sb);
508 }
509
510 /*
511  * bitmap_new_disk_sb
512  * @bitmap
513  *
514  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
515  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
516  * This function verifies 'bitmap_info' and populates the on-disk bitmap
517  * structure, which is to be written to disk.
518  *
519  * Returns: 0 on success, -Exxx on error
520  */
521 static int bitmap_new_disk_sb(struct bitmap *bitmap)
522 {
523         bitmap_super_t *sb;
524         unsigned long chunksize, daemon_sleep, write_behind;
525
526         bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
527         if (bitmap->storage.sb_page == NULL)
528                 return -ENOMEM;
529         bitmap->storage.sb_page->index = 0;
530
531         sb = kmap_atomic(bitmap->storage.sb_page);
532
533         sb->magic = cpu_to_le32(BITMAP_MAGIC);
534         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
535
536         chunksize = bitmap->mddev->bitmap_info.chunksize;
537         BUG_ON(!chunksize);
538         if (!is_power_of_2(chunksize)) {
539                 kunmap_atomic(sb);
540                 pr_warn("bitmap chunksize not a power of 2\n");
541                 return -EINVAL;
542         }
543         sb->chunksize = cpu_to_le32(chunksize);
544
545         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
546         if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
547                 pr_debug("Choosing daemon_sleep default (5 sec)\n");
548                 daemon_sleep = 5 * HZ;
549         }
550         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
551         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
552
553         /*
554          * FIXME: write_behind for RAID1.  If not specified, what
555          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
556          */
557         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
558         if (write_behind > COUNTER_MAX)
559                 write_behind = COUNTER_MAX / 2;
560         sb->write_behind = cpu_to_le32(write_behind);
561         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
562
563         /* keep the array size field of the bitmap superblock up to date */
564         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
565
566         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
567
568         set_bit(BITMAP_STALE, &bitmap->flags);
569         sb->state = cpu_to_le32(bitmap->flags);
570         bitmap->events_cleared = bitmap->mddev->events;
571         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
572         bitmap->mddev->bitmap_info.nodes = 0;
573
574         kunmap_atomic(sb);
575
576         return 0;
577 }
578
579 /* read the superblock from the bitmap file and initialize some bitmap fields */
580 static int bitmap_read_sb(struct bitmap *bitmap)
581 {
582         char *reason = NULL;
583         bitmap_super_t *sb;
584         unsigned long chunksize, daemon_sleep, write_behind;
585         unsigned long long events;
586         int nodes = 0;
587         unsigned long sectors_reserved = 0;
588         int err = -EINVAL;
589         struct page *sb_page;
590         loff_t offset = bitmap->mddev->bitmap_info.offset;
591
592         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
593                 chunksize = 128 * 1024 * 1024;
594                 daemon_sleep = 5 * HZ;
595                 write_behind = 0;
596                 set_bit(BITMAP_STALE, &bitmap->flags);
597                 err = 0;
598                 goto out_no_sb;
599         }
600         /* page 0 is the superblock, read it... */
601         sb_page = alloc_page(GFP_KERNEL);
602         if (!sb_page)
603                 return -ENOMEM;
604         bitmap->storage.sb_page = sb_page;
605
606 re_read:
607         /* If cluster_slot is set, the cluster is setup */
608         if (bitmap->cluster_slot >= 0) {
609                 sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
610
611                 sector_div(bm_blocks,
612                            bitmap->mddev->bitmap_info.chunksize >> 9);
613                 /* bits to bytes */
614                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
615                 /* to 4k blocks */
616                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
617                 offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
618                 pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
619                         bitmap->cluster_slot, offset);
620         }
621
622         if (bitmap->storage.file) {
623                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
624                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
625
626                 err = read_page(bitmap->storage.file, 0,
627                                 bitmap, bytes, sb_page);
628         } else {
629                 err = read_sb_page(bitmap->mddev,
630                                    offset,
631                                    sb_page,
632                                    0, sizeof(bitmap_super_t));
633         }
634         if (err)
635                 return err;
636
637         err = -EINVAL;
638         sb = kmap_atomic(sb_page);
639
640         chunksize = le32_to_cpu(sb->chunksize);
641         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
642         write_behind = le32_to_cpu(sb->write_behind);
643         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
644         /* Setup nodes/clustername only if bitmap version is
645          * cluster-compatible
646          */
647         if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
648                 nodes = le32_to_cpu(sb->nodes);
649                 strlcpy(bitmap->mddev->bitmap_info.cluster_name,
650                                 sb->cluster_name, 64);
651         }
652
653         /* verify that the bitmap-specific fields are valid */
654         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
655                 reason = "bad magic";
656         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
657                  le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
658                 reason = "unrecognized superblock version";
659         else if (chunksize < 512)
660                 reason = "bitmap chunksize too small";
661         else if (!is_power_of_2(chunksize))
662                 reason = "bitmap chunksize not a power of 2";
663         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
664                 reason = "daemon sleep period out of range";
665         else if (write_behind > COUNTER_MAX)
666                 reason = "write-behind limit out of range (0 - 16383)";
667         if (reason) {
668                 pr_warn("%s: invalid bitmap file superblock: %s\n",
669                         bmname(bitmap), reason);
670                 goto out;
671         }
672
673         /* keep the array size field of the bitmap superblock up to date */
674         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
675
676         if (bitmap->mddev->persistent) {
677                 /*
678                  * We have a persistent array superblock, so compare the
679                  * bitmap's UUID and event counter to the mddev's
680                  */
681                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
682                         pr_warn("%s: bitmap superblock UUID mismatch\n",
683                                 bmname(bitmap));
684                         goto out;
685                 }
686                 events = le64_to_cpu(sb->events);
687                 if (!nodes && (events < bitmap->mddev->events)) {
688                         pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
689                                 bmname(bitmap), events,
690                                 (unsigned long long) bitmap->mddev->events);
691                         set_bit(BITMAP_STALE, &bitmap->flags);
692                 }
693         }
694
695         /* assign fields using values from superblock */
696         bitmap->flags |= le32_to_cpu(sb->state);
697         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
698                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
699         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
700         strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
701         err = 0;
702
703 out:
704         kunmap_atomic(sb);
705         /* Assigning chunksize is required for "re_read" */
706         bitmap->mddev->bitmap_info.chunksize = chunksize;
707         if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
708                 err = md_setup_cluster(bitmap->mddev, nodes);
709                 if (err) {
710                         pr_warn("%s: Could not setup cluster service (%d)\n",
711                                 bmname(bitmap), err);
712                         goto out_no_sb;
713                 }
714                 bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
715                 goto re_read;
716         }
717
718
719 out_no_sb:
720         if (test_bit(BITMAP_STALE, &bitmap->flags))
721                 bitmap->events_cleared = bitmap->mddev->events;
722         bitmap->mddev->bitmap_info.chunksize = chunksize;
723         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
724         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
725         bitmap->mddev->bitmap_info.nodes = nodes;
726         if (bitmap->mddev->bitmap_info.space == 0 ||
727             bitmap->mddev->bitmap_info.space > sectors_reserved)
728                 bitmap->mddev->bitmap_info.space = sectors_reserved;
729         if (err) {
730                 bitmap_print_sb(bitmap);
731                 if (bitmap->cluster_slot < 0)
732                         md_cluster_stop(bitmap->mddev);
733         }
734         return err;
735 }
736
737 /*
738  * general bitmap file operations
739  */
740
741 /*
742  * on-disk bitmap:
743  *
744  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
745  * file a page at a time. There's a superblock at the start of the file.
746  */
747 /* calculate the index of the page that contains this bit */
748 static inline unsigned long file_page_index(struct bitmap_storage *store,
749                                             unsigned long chunk)
750 {
751         if (store->sb_page)
752                 chunk += sizeof(bitmap_super_t) << 3;
753         return chunk >> PAGE_BIT_SHIFT;
754 }
755
756 /* calculate the (bit) offset of this bit within a page */
757 static inline unsigned long file_page_offset(struct bitmap_storage *store,
758                                              unsigned long chunk)
759 {
760         if (store->sb_page)
761                 chunk += sizeof(bitmap_super_t) << 3;
762         return chunk & (PAGE_BITS - 1);
763 }
764
765 /*
766  * return a pointer to the page in the filemap that contains the given bit
767  *
768  */
769 static inline struct page *filemap_get_page(struct bitmap_storage *store,
770                                             unsigned long chunk)
771 {
772         if (file_page_index(store, chunk) >= store->file_pages)
773                 return NULL;
774         return store->filemap[file_page_index(store, chunk)];
775 }
776
777 static int bitmap_storage_alloc(struct bitmap_storage *store,
778                                 unsigned long chunks, int with_super,
779                                 int slot_number)
780 {
781         int pnum, offset = 0;
782         unsigned long num_pages;
783         unsigned long bytes;
784
785         bytes = DIV_ROUND_UP(chunks, 8);
786         if (with_super)
787                 bytes += sizeof(bitmap_super_t);
788
789         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
790         offset = slot_number * num_pages;
791
792         store->filemap = kmalloc(sizeof(struct page *)
793                                  * num_pages, GFP_KERNEL);
794         if (!store->filemap)
795                 return -ENOMEM;
796
797         if (with_super && !store->sb_page) {
798                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
799                 if (store->sb_page == NULL)
800                         return -ENOMEM;
801         }
802
803         pnum = 0;
804         if (store->sb_page) {
805                 store->filemap[0] = store->sb_page;
806                 pnum = 1;
807                 store->sb_page->index = offset;
808         }
809
810         for ( ; pnum < num_pages; pnum++) {
811                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
812                 if (!store->filemap[pnum]) {
813                         store->file_pages = pnum;
814                         return -ENOMEM;
815                 }
816                 store->filemap[pnum]->index = pnum + offset;
817         }
818         store->file_pages = pnum;
819
820         /* We need 4 bits per page, rounded up to a multiple
821          * of sizeof(unsigned long) */
822         store->filemap_attr = kzalloc(
823                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
824                 GFP_KERNEL);
825         if (!store->filemap_attr)
826                 return -ENOMEM;
827
828         store->bytes = bytes;
829
830         return 0;
831 }
832
833 static void bitmap_file_unmap(struct bitmap_storage *store)
834 {
835         struct page **map, *sb_page;
836         int pages;
837         struct file *file;
838
839         file = store->file;
840         map = store->filemap;
841         pages = store->file_pages;
842         sb_page = store->sb_page;
843
844         while (pages--)
845                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
846                         free_buffers(map[pages]);
847         kfree(map);
848         kfree(store->filemap_attr);
849
850         if (sb_page)
851                 free_buffers(sb_page);
852
853         if (file) {
854                 struct inode *inode = file_inode(file);
855                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
856                 fput(file);
857         }
858 }
859
860 /*
861  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
862  * then it is no longer reliable, so we stop using it and we mark the file
863  * as failed in the superblock
864  */
865 static void bitmap_file_kick(struct bitmap *bitmap)
866 {
867         char *path, *ptr = NULL;
868
869         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
870                 bitmap_update_sb(bitmap);
871
872                 if (bitmap->storage.file) {
873                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
874                         if (path)
875                                 ptr = file_path(bitmap->storage.file,
876                                              path, PAGE_SIZE);
877
878                         pr_warn("%s: kicking failed bitmap file %s from array!\n",
879                                 bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
880
881                         kfree(path);
882                 } else
883                         pr_warn("%s: disabling internal bitmap due to errors\n",
884                                 bmname(bitmap));
885         }
886 }
887
888 enum bitmap_page_attr {
889         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
890         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
891                                     * i.e. counter is 1 or 2. */
892         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
893 };
894
895 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
896                                  enum bitmap_page_attr attr)
897 {
898         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
899 }
900
901 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
902                                    enum bitmap_page_attr attr)
903 {
904         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
905 }
906
907 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
908                                  enum bitmap_page_attr attr)
909 {
910         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
911 }
912
913 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
914                                            enum bitmap_page_attr attr)
915 {
916         return test_and_clear_bit((pnum<<2) + attr,
917                                   bitmap->storage.filemap_attr);
918 }
919 /*
920  * bitmap_file_set_bit -- called before performing a write to the md device
921  * to set (and eventually sync) a particular bit in the bitmap file
922  *
923  * we set the bit immediately, then we record the page number so that
924  * when an unplug occurs, we can flush the dirty pages out to disk
925  */
926 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
927 {
928         unsigned long bit;
929         struct page *page;
930         void *kaddr;
931         unsigned long chunk = block >> bitmap->counts.chunkshift;
932         struct bitmap_storage *store = &bitmap->storage;
933         unsigned long node_offset = 0;
934
935         if (mddev_is_clustered(bitmap->mddev))
936                 node_offset = bitmap->cluster_slot * store->file_pages;
937
938         page = filemap_get_page(&bitmap->storage, chunk);
939         if (!page)
940                 return;
941         bit = file_page_offset(&bitmap->storage, chunk);
942
943         /* set the bit */
944         kaddr = kmap_atomic(page);
945         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
946                 set_bit(bit, kaddr);
947         else
948                 set_bit_le(bit, kaddr);
949         kunmap_atomic(kaddr);
950         pr_debug("set file bit %lu page %lu\n", bit, page->index);
951         /* record page number so it gets flushed to disk when unplug occurs */
952         set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
953 }
954
955 static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
956 {
957         unsigned long bit;
958         struct page *page;
959         void *paddr;
960         unsigned long chunk = block >> bitmap->counts.chunkshift;
961         struct bitmap_storage *store = &bitmap->storage;
962         unsigned long node_offset = 0;
963
964         if (mddev_is_clustered(bitmap->mddev))
965                 node_offset = bitmap->cluster_slot * store->file_pages;
966
967         page = filemap_get_page(&bitmap->storage, chunk);
968         if (!page)
969                 return;
970         bit = file_page_offset(&bitmap->storage, chunk);
971         paddr = kmap_atomic(page);
972         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
973                 clear_bit(bit, paddr);
974         else
975                 clear_bit_le(bit, paddr);
976         kunmap_atomic(paddr);
977         if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
978                 set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
979                 bitmap->allclean = 0;
980         }
981 }
982
983 static int bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
984 {
985         unsigned long bit;
986         struct page *page;
987         void *paddr;
988         unsigned long chunk = block >> bitmap->counts.chunkshift;
989         int set = 0;
990
991         page = filemap_get_page(&bitmap->storage, chunk);
992         if (!page)
993                 return -EINVAL;
994         bit = file_page_offset(&bitmap->storage, chunk);
995         paddr = kmap_atomic(page);
996         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
997                 set = test_bit(bit, paddr);
998         else
999                 set = test_bit_le(bit, paddr);
1000         kunmap_atomic(paddr);
1001         return set;
1002 }
1003
1004
1005 /* this gets called when the md device is ready to unplug its underlying
1006  * (slave) device queues -- before we let any writes go down, we need to
1007  * sync the dirty pages of the bitmap file to disk */
1008 void bitmap_unplug(struct bitmap *bitmap)
1009 {
1010         unsigned long i;
1011         int dirty, need_write;
1012         int writing = 0;
1013
1014         if (!bitmap || !bitmap->storage.filemap ||
1015             test_bit(BITMAP_STALE, &bitmap->flags))
1016                 return;
1017
1018         /* look at each page to see if there are any set bits that need to be
1019          * flushed out to disk */
1020         for (i = 0; i < bitmap->storage.file_pages; i++) {
1021                 if (!bitmap->storage.filemap)
1022                         return;
1023                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1024                 need_write = test_and_clear_page_attr(bitmap, i,
1025                                                       BITMAP_PAGE_NEEDWRITE);
1026                 if (dirty || need_write) {
1027                         if (!writing) {
1028                                 bitmap_wait_writes(bitmap);
1029                                 if (bitmap->mddev->queue)
1030                                         blk_add_trace_msg(bitmap->mddev->queue,
1031                                                           "md bitmap_unplug");
1032                         }
1033                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
1034                         write_page(bitmap, bitmap->storage.filemap[i], 0);
1035                         writing = 1;
1036                 }
1037         }
1038         if (writing)
1039                 bitmap_wait_writes(bitmap);
1040
1041         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1042                 bitmap_file_kick(bitmap);
1043 }
1044 EXPORT_SYMBOL(bitmap_unplug);
1045
1046 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1047 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
1048  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
1049  * memory mapping of the bitmap file
1050  * Special cases:
1051  *   if there's no bitmap file, or if the bitmap file had been
1052  *   previously kicked from the array, we mark all the bits as
1053  *   1's in order to cause a full resync.
1054  *
1055  * We ignore all bits for sectors that end earlier than 'start'.
1056  * This is used when reading an out-of-date bitmap...
1057  */
1058 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1059 {
1060         unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
1061         struct page *page = NULL;
1062         unsigned long bit_cnt = 0;
1063         struct file *file;
1064         unsigned long offset;
1065         int outofdate;
1066         int ret = -ENOSPC;
1067         void *paddr;
1068         struct bitmap_storage *store = &bitmap->storage;
1069
1070         chunks = bitmap->counts.chunks;
1071         file = store->file;
1072
1073         if (!file && !bitmap->mddev->bitmap_info.offset) {
1074                 /* No permanent bitmap - fill with '1s'. */
1075                 store->filemap = NULL;
1076                 store->file_pages = 0;
1077                 for (i = 0; i < chunks ; i++) {
1078                         /* if the disk bit is set, set the memory bit */
1079                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1080                                       >= start);
1081                         bitmap_set_memory_bits(bitmap,
1082                                                (sector_t)i << bitmap->counts.chunkshift,
1083                                                needed);
1084                 }
1085                 return 0;
1086         }
1087
1088         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1089         if (outofdate)
1090                 pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
1091
1092         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
1093                 pr_warn("%s: bitmap file too short %lu < %lu\n",
1094                         bmname(bitmap),
1095                         (unsigned long) i_size_read(file->f_mapping->host),
1096                         store->bytes);
1097                 goto err;
1098         }
1099
1100         oldindex = ~0L;
1101         offset = 0;
1102         if (!bitmap->mddev->bitmap_info.external)
1103                 offset = sizeof(bitmap_super_t);
1104
1105         if (mddev_is_clustered(bitmap->mddev))
1106                 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1107
1108         for (i = 0; i < chunks; i++) {
1109                 int b;
1110                 index = file_page_index(&bitmap->storage, i);
1111                 bit = file_page_offset(&bitmap->storage, i);
1112                 if (index != oldindex) { /* this is a new page, read it in */
1113                         int count;
1114                         /* unmap the old page, we're done with it */
1115                         if (index == store->file_pages-1)
1116                                 count = store->bytes - index * PAGE_SIZE;
1117                         else
1118                                 count = PAGE_SIZE;
1119                         page = store->filemap[index];
1120                         if (file)
1121                                 ret = read_page(file, index, bitmap,
1122                                                 count, page);
1123                         else
1124                                 ret = read_sb_page(
1125                                         bitmap->mddev,
1126                                         bitmap->mddev->bitmap_info.offset,
1127                                         page,
1128                                         index + node_offset, count);
1129
1130                         if (ret)
1131                                 goto err;
1132
1133                         oldindex = index;
1134
1135                         if (outofdate) {
1136                                 /*
1137                                  * if bitmap is out of date, dirty the
1138                                  * whole page and write it out
1139                                  */
1140                                 paddr = kmap_atomic(page);
1141                                 memset(paddr + offset, 0xff,
1142                                        PAGE_SIZE - offset);
1143                                 kunmap_atomic(paddr);
1144                                 write_page(bitmap, page, 1);
1145
1146                                 ret = -EIO;
1147                                 if (test_bit(BITMAP_WRITE_ERROR,
1148                                              &bitmap->flags))
1149                                         goto err;
1150                         }
1151                 }
1152                 paddr = kmap_atomic(page);
1153                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1154                         b = test_bit(bit, paddr);
1155                 else
1156                         b = test_bit_le(bit, paddr);
1157                 kunmap_atomic(paddr);
1158                 if (b) {
1159                         /* if the disk bit is set, set the memory bit */
1160                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1161                                       >= start);
1162                         bitmap_set_memory_bits(bitmap,
1163                                                (sector_t)i << bitmap->counts.chunkshift,
1164                                                needed);
1165                         bit_cnt++;
1166                 }
1167                 offset = 0;
1168         }
1169
1170         pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1171                  bmname(bitmap), store->file_pages,
1172                  bit_cnt, chunks);
1173
1174         return 0;
1175
1176  err:
1177         pr_warn("%s: bitmap initialisation failed: %d\n",
1178                 bmname(bitmap), ret);
1179         return ret;
1180 }
1181
1182 void bitmap_write_all(struct bitmap *bitmap)
1183 {
1184         /* We don't actually write all bitmap blocks here,
1185          * just flag them as needing to be written
1186          */
1187         int i;
1188
1189         if (!bitmap || !bitmap->storage.filemap)
1190                 return;
1191         if (bitmap->storage.file)
1192                 /* Only one copy, so nothing needed */
1193                 return;
1194
1195         for (i = 0; i < bitmap->storage.file_pages; i++)
1196                 set_page_attr(bitmap, i,
1197                               BITMAP_PAGE_NEEDWRITE);
1198         bitmap->allclean = 0;
1199 }
1200
1201 static void bitmap_count_page(struct bitmap_counts *bitmap,
1202                               sector_t offset, int inc)
1203 {
1204         sector_t chunk = offset >> bitmap->chunkshift;
1205         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1206         bitmap->bp[page].count += inc;
1207         bitmap_checkfree(bitmap, page);
1208 }
1209
1210 static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1211 {
1212         sector_t chunk = offset >> bitmap->chunkshift;
1213         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1214         struct bitmap_page *bp = &bitmap->bp[page];
1215
1216         if (!bp->pending)
1217                 bp->pending = 1;
1218 }
1219
1220 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1221                                             sector_t offset, sector_t *blocks,
1222                                             int create);
1223
1224 /*
1225  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1226  *                      out to disk
1227  */
1228
1229 void bitmap_daemon_work(struct mddev *mddev)
1230 {
1231         struct bitmap *bitmap;
1232         unsigned long j;
1233         unsigned long nextpage;
1234         sector_t blocks;
1235         struct bitmap_counts *counts;
1236
1237         /* Use a mutex to guard daemon_work against
1238          * bitmap_destroy.
1239          */
1240         mutex_lock(&mddev->bitmap_info.mutex);
1241         bitmap = mddev->bitmap;
1242         if (bitmap == NULL) {
1243                 mutex_unlock(&mddev->bitmap_info.mutex);
1244                 return;
1245         }
1246         if (time_before(jiffies, bitmap->daemon_lastrun
1247                         + mddev->bitmap_info.daemon_sleep))
1248                 goto done;
1249
1250         bitmap->daemon_lastrun = jiffies;
1251         if (bitmap->allclean) {
1252                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1253                 goto done;
1254         }
1255         bitmap->allclean = 1;
1256
1257         if (bitmap->mddev->queue)
1258                 blk_add_trace_msg(bitmap->mddev->queue,
1259                                   "md bitmap_daemon_work");
1260
1261         /* Any file-page which is PENDING now needs to be written.
1262          * So set NEEDWRITE now, then after we make any last-minute changes
1263          * we will write it.
1264          */
1265         for (j = 0; j < bitmap->storage.file_pages; j++)
1266                 if (test_and_clear_page_attr(bitmap, j,
1267                                              BITMAP_PAGE_PENDING))
1268                         set_page_attr(bitmap, j,
1269                                       BITMAP_PAGE_NEEDWRITE);
1270
1271         if (bitmap->need_sync &&
1272             mddev->bitmap_info.external == 0) {
1273                 /* Arrange for superblock update as well as
1274                  * other changes */
1275                 bitmap_super_t *sb;
1276                 bitmap->need_sync = 0;
1277                 if (bitmap->storage.filemap) {
1278                         sb = kmap_atomic(bitmap->storage.sb_page);
1279                         sb->events_cleared =
1280                                 cpu_to_le64(bitmap->events_cleared);
1281                         kunmap_atomic(sb);
1282                         set_page_attr(bitmap, 0,
1283                                       BITMAP_PAGE_NEEDWRITE);
1284                 }
1285         }
1286         /* Now look at the bitmap counters and if any are '2' or '1',
1287          * decrement and handle accordingly.
1288          */
1289         counts = &bitmap->counts;
1290         spin_lock_irq(&counts->lock);
1291         nextpage = 0;
1292         for (j = 0; j < counts->chunks; j++) {
1293                 bitmap_counter_t *bmc;
1294                 sector_t  block = (sector_t)j << counts->chunkshift;
1295
1296                 if (j == nextpage) {
1297                         nextpage += PAGE_COUNTER_RATIO;
1298                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1299                                 j |= PAGE_COUNTER_MASK;
1300                                 continue;
1301                         }
1302                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1303                 }
1304                 bmc = bitmap_get_counter(counts,
1305                                          block,
1306                                          &blocks, 0);
1307
1308                 if (!bmc) {
1309                         j |= PAGE_COUNTER_MASK;
1310                         continue;
1311                 }
1312                 if (*bmc == 1 && !bitmap->need_sync) {
1313                         /* We can clear the bit */
1314                         *bmc = 0;
1315                         bitmap_count_page(counts, block, -1);
1316                         bitmap_file_clear_bit(bitmap, block);
1317                 } else if (*bmc && *bmc <= 2) {
1318                         *bmc = 1;
1319                         bitmap_set_pending(counts, block);
1320                         bitmap->allclean = 0;
1321                 }
1322         }
1323         spin_unlock_irq(&counts->lock);
1324
1325         bitmap_wait_writes(bitmap);
1326         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1327          * DIRTY pages need to be written by bitmap_unplug so it can wait
1328          * for them.
1329          * If we find any DIRTY page we stop there and let bitmap_unplug
1330          * handle all the rest.  This is important in the case where
1331          * the first blocking holds the superblock and it has been updated.
1332          * We mustn't write any other blocks before the superblock.
1333          */
1334         for (j = 0;
1335              j < bitmap->storage.file_pages
1336                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1337              j++) {
1338                 if (test_page_attr(bitmap, j,
1339                                    BITMAP_PAGE_DIRTY))
1340                         /* bitmap_unplug will handle the rest */
1341                         break;
1342                 if (test_and_clear_page_attr(bitmap, j,
1343                                              BITMAP_PAGE_NEEDWRITE)) {
1344                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1345                 }
1346         }
1347
1348  done:
1349         if (bitmap->allclean == 0)
1350                 mddev->thread->timeout =
1351                         mddev->bitmap_info.daemon_sleep;
1352         mutex_unlock(&mddev->bitmap_info.mutex);
1353 }
1354
1355 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1356                                             sector_t offset, sector_t *blocks,
1357                                             int create)
1358 __releases(bitmap->lock)
1359 __acquires(bitmap->lock)
1360 {
1361         /* If 'create', we might release the lock and reclaim it.
1362          * The lock must have been taken with interrupts enabled.
1363          * If !create, we don't release the lock.
1364          */
1365         sector_t chunk = offset >> bitmap->chunkshift;
1366         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1367         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1368         sector_t csize;
1369         int err;
1370
1371         err = bitmap_checkpage(bitmap, page, create, 0);
1372
1373         if (bitmap->bp[page].hijacked ||
1374             bitmap->bp[page].map == NULL)
1375                 csize = ((sector_t)1) << (bitmap->chunkshift +
1376                                           PAGE_COUNTER_SHIFT - 1);
1377         else
1378                 csize = ((sector_t)1) << bitmap->chunkshift;
1379         *blocks = csize - (offset & (csize - 1));
1380
1381         if (err < 0)
1382                 return NULL;
1383
1384         /* now locked ... */
1385
1386         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1387                 /* should we use the first or second counter field
1388                  * of the hijacked pointer? */
1389                 int hi = (pageoff > PAGE_COUNTER_MASK);
1390                 return  &((bitmap_counter_t *)
1391                           &bitmap->bp[page].map)[hi];
1392         } else /* page is allocated */
1393                 return (bitmap_counter_t *)
1394                         &(bitmap->bp[page].map[pageoff]);
1395 }
1396
1397 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1398 {
1399         if (!bitmap)
1400                 return 0;
1401
1402         if (behind) {
1403                 int bw;
1404                 atomic_inc(&bitmap->behind_writes);
1405                 bw = atomic_read(&bitmap->behind_writes);
1406                 if (bw > bitmap->behind_writes_used)
1407                         bitmap->behind_writes_used = bw;
1408
1409                 pr_debug("inc write-behind count %d/%lu\n",
1410                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1411         }
1412
1413         while (sectors) {
1414                 sector_t blocks;
1415                 bitmap_counter_t *bmc;
1416
1417                 spin_lock_irq(&bitmap->counts.lock);
1418                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1419                 if (!bmc) {
1420                         spin_unlock_irq(&bitmap->counts.lock);
1421                         return 0;
1422                 }
1423
1424                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1425                         DEFINE_WAIT(__wait);
1426                         /* note that it is safe to do the prepare_to_wait
1427                          * after the test as long as we do it before dropping
1428                          * the spinlock.
1429                          */
1430                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1431                                         TASK_UNINTERRUPTIBLE);
1432                         spin_unlock_irq(&bitmap->counts.lock);
1433                         schedule();
1434                         finish_wait(&bitmap->overflow_wait, &__wait);
1435                         continue;
1436                 }
1437
1438                 switch (*bmc) {
1439                 case 0:
1440                         bitmap_file_set_bit(bitmap, offset);
1441                         bitmap_count_page(&bitmap->counts, offset, 1);
1442                         /* fall through */
1443                 case 1:
1444                         *bmc = 2;
1445                 }
1446
1447                 (*bmc)++;
1448
1449                 spin_unlock_irq(&bitmap->counts.lock);
1450
1451                 offset += blocks;
1452                 if (sectors > blocks)
1453                         sectors -= blocks;
1454                 else
1455                         sectors = 0;
1456         }
1457         return 0;
1458 }
1459 EXPORT_SYMBOL(bitmap_startwrite);
1460
1461 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1462                      int success, int behind)
1463 {
1464         if (!bitmap)
1465                 return;
1466         if (behind) {
1467                 if (atomic_dec_and_test(&bitmap->behind_writes))
1468                         wake_up(&bitmap->behind_wait);
1469                 pr_debug("dec write-behind count %d/%lu\n",
1470                          atomic_read(&bitmap->behind_writes),
1471                          bitmap->mddev->bitmap_info.max_write_behind);
1472         }
1473
1474         while (sectors) {
1475                 sector_t blocks;
1476                 unsigned long flags;
1477                 bitmap_counter_t *bmc;
1478
1479                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1480                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1481                 if (!bmc) {
1482                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1483                         return;
1484                 }
1485
1486                 if (success && !bitmap->mddev->degraded &&
1487                     bitmap->events_cleared < bitmap->mddev->events) {
1488                         bitmap->events_cleared = bitmap->mddev->events;
1489                         bitmap->need_sync = 1;
1490                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1491                 }
1492
1493                 if (!success && !NEEDED(*bmc))
1494                         *bmc |= NEEDED_MASK;
1495
1496                 if (COUNTER(*bmc) == COUNTER_MAX)
1497                         wake_up(&bitmap->overflow_wait);
1498
1499                 (*bmc)--;
1500                 if (*bmc <= 2) {
1501                         bitmap_set_pending(&bitmap->counts, offset);
1502                         bitmap->allclean = 0;
1503                 }
1504                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1505                 offset += blocks;
1506                 if (sectors > blocks)
1507                         sectors -= blocks;
1508                 else
1509                         sectors = 0;
1510         }
1511 }
1512 EXPORT_SYMBOL(bitmap_endwrite);
1513
1514 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1515                                int degraded)
1516 {
1517         bitmap_counter_t *bmc;
1518         int rv;
1519         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1520                 *blocks = 1024;
1521                 return 1; /* always resync if no bitmap */
1522         }
1523         spin_lock_irq(&bitmap->counts.lock);
1524         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1525         rv = 0;
1526         if (bmc) {
1527                 /* locked */
1528                 if (RESYNC(*bmc))
1529                         rv = 1;
1530                 else if (NEEDED(*bmc)) {
1531                         rv = 1;
1532                         if (!degraded) { /* don't set/clear bits if degraded */
1533                                 *bmc |= RESYNC_MASK;
1534                                 *bmc &= ~NEEDED_MASK;
1535                         }
1536                 }
1537         }
1538         spin_unlock_irq(&bitmap->counts.lock);
1539         return rv;
1540 }
1541
1542 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1543                       int degraded)
1544 {
1545         /* bitmap_start_sync must always report on multiples of whole
1546          * pages, otherwise resync (which is very PAGE_SIZE based) will
1547          * get confused.
1548          * So call __bitmap_start_sync repeatedly (if needed) until
1549          * At least PAGE_SIZE>>9 blocks are covered.
1550          * Return the 'or' of the result.
1551          */
1552         int rv = 0;
1553         sector_t blocks1;
1554
1555         *blocks = 0;
1556         while (*blocks < (PAGE_SIZE>>9)) {
1557                 rv |= __bitmap_start_sync(bitmap, offset,
1558                                           &blocks1, degraded);
1559                 offset += blocks1;
1560                 *blocks += blocks1;
1561         }
1562         return rv;
1563 }
1564 EXPORT_SYMBOL(bitmap_start_sync);
1565
1566 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1567 {
1568         bitmap_counter_t *bmc;
1569         unsigned long flags;
1570
1571         if (bitmap == NULL) {
1572                 *blocks = 1024;
1573                 return;
1574         }
1575         spin_lock_irqsave(&bitmap->counts.lock, flags);
1576         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1577         if (bmc == NULL)
1578                 goto unlock;
1579         /* locked */
1580         if (RESYNC(*bmc)) {
1581                 *bmc &= ~RESYNC_MASK;
1582
1583                 if (!NEEDED(*bmc) && aborted)
1584                         *bmc |= NEEDED_MASK;
1585                 else {
1586                         if (*bmc <= 2) {
1587                                 bitmap_set_pending(&bitmap->counts, offset);
1588                                 bitmap->allclean = 0;
1589                         }
1590                 }
1591         }
1592  unlock:
1593         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1594 }
1595 EXPORT_SYMBOL(bitmap_end_sync);
1596
1597 void bitmap_close_sync(struct bitmap *bitmap)
1598 {
1599         /* Sync has finished, and any bitmap chunks that weren't synced
1600          * properly have been aborted.  It remains to us to clear the
1601          * RESYNC bit wherever it is still on
1602          */
1603         sector_t sector = 0;
1604         sector_t blocks;
1605         if (!bitmap)
1606                 return;
1607         while (sector < bitmap->mddev->resync_max_sectors) {
1608                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1609                 sector += blocks;
1610         }
1611 }
1612 EXPORT_SYMBOL(bitmap_close_sync);
1613
1614 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1615 {
1616         sector_t s = 0;
1617         sector_t blocks;
1618
1619         if (!bitmap)
1620                 return;
1621         if (sector == 0) {
1622                 bitmap->last_end_sync = jiffies;
1623                 return;
1624         }
1625         if (!force && time_before(jiffies, (bitmap->last_end_sync
1626                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1627                 return;
1628         wait_event(bitmap->mddev->recovery_wait,
1629                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1630
1631         bitmap->mddev->curr_resync_completed = sector;
1632         set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1633         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1634         s = 0;
1635         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1636                 bitmap_end_sync(bitmap, s, &blocks, 0);
1637                 s += blocks;
1638         }
1639         bitmap->last_end_sync = jiffies;
1640         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1641 }
1642 EXPORT_SYMBOL(bitmap_cond_end_sync);
1643
1644 void bitmap_sync_with_cluster(struct mddev *mddev,
1645                               sector_t old_lo, sector_t old_hi,
1646                               sector_t new_lo, sector_t new_hi)
1647 {
1648         struct bitmap *bitmap = mddev->bitmap;
1649         sector_t sector, blocks = 0;
1650
1651         for (sector = old_lo; sector < new_lo; ) {
1652                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1653                 sector += blocks;
1654         }
1655         WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1656
1657         for (sector = old_hi; sector < new_hi; ) {
1658                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1659                 sector += blocks;
1660         }
1661         WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1662 }
1663 EXPORT_SYMBOL(bitmap_sync_with_cluster);
1664
1665 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1666 {
1667         /* For each chunk covered by any of these sectors, set the
1668          * counter to 2 and possibly set resync_needed.  They should all
1669          * be 0 at this point
1670          */
1671
1672         sector_t secs;
1673         bitmap_counter_t *bmc;
1674         spin_lock_irq(&bitmap->counts.lock);
1675         bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1676         if (!bmc) {
1677                 spin_unlock_irq(&bitmap->counts.lock);
1678                 return;
1679         }
1680         if (!*bmc) {
1681                 *bmc = 2;
1682                 bitmap_count_page(&bitmap->counts, offset, 1);
1683                 bitmap_set_pending(&bitmap->counts, offset);
1684                 bitmap->allclean = 0;
1685         }
1686         if (needed)
1687                 *bmc |= NEEDED_MASK;
1688         spin_unlock_irq(&bitmap->counts.lock);
1689 }
1690
1691 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1692 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1693 {
1694         unsigned long chunk;
1695
1696         for (chunk = s; chunk <= e; chunk++) {
1697                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1698                 bitmap_set_memory_bits(bitmap, sec, 1);
1699                 bitmap_file_set_bit(bitmap, sec);
1700                 if (sec < bitmap->mddev->recovery_cp)
1701                         /* We are asserting that the array is dirty,
1702                          * so move the recovery_cp address back so
1703                          * that it is obvious that it is dirty
1704                          */
1705                         bitmap->mddev->recovery_cp = sec;
1706         }
1707 }
1708
1709 /*
1710  * flush out any pending updates
1711  */
1712 void bitmap_flush(struct mddev *mddev)
1713 {
1714         struct bitmap *bitmap = mddev->bitmap;
1715         long sleep;
1716
1717         if (!bitmap) /* there was no bitmap */
1718                 return;
1719
1720         /* run the daemon_work three time to ensure everything is flushed
1721          * that can be
1722          */
1723         sleep = mddev->bitmap_info.daemon_sleep * 2;
1724         bitmap->daemon_lastrun -= sleep;
1725         bitmap_daemon_work(mddev);
1726         bitmap->daemon_lastrun -= sleep;
1727         bitmap_daemon_work(mddev);
1728         bitmap->daemon_lastrun -= sleep;
1729         bitmap_daemon_work(mddev);
1730         bitmap_update_sb(bitmap);
1731 }
1732
1733 /*
1734  * free memory that was allocated
1735  */
1736 void bitmap_free(struct bitmap *bitmap)
1737 {
1738         unsigned long k, pages;
1739         struct bitmap_page *bp;
1740
1741         if (!bitmap) /* there was no bitmap */
1742                 return;
1743
1744         if (bitmap->sysfs_can_clear)
1745                 sysfs_put(bitmap->sysfs_can_clear);
1746
1747         if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1748                 bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1749                 md_cluster_stop(bitmap->mddev);
1750
1751         /* Shouldn't be needed - but just in case.... */
1752         wait_event(bitmap->write_wait,
1753                    atomic_read(&bitmap->pending_writes) == 0);
1754
1755         /* release the bitmap file  */
1756         bitmap_file_unmap(&bitmap->storage);
1757
1758         bp = bitmap->counts.bp;
1759         pages = bitmap->counts.pages;
1760
1761         /* free all allocated memory */
1762
1763         if (bp) /* deallocate the page memory */
1764                 for (k = 0; k < pages; k++)
1765                         if (bp[k].map && !bp[k].hijacked)
1766                                 kfree(bp[k].map);
1767         kfree(bp);
1768         kfree(bitmap);
1769 }
1770 EXPORT_SYMBOL(bitmap_free);
1771
1772 void bitmap_wait_behind_writes(struct mddev *mddev)
1773 {
1774         struct bitmap *bitmap = mddev->bitmap;
1775
1776         /* wait for behind writes to complete */
1777         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1778                 pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1779                          mdname(mddev));
1780                 /* need to kick something here to make sure I/O goes? */
1781                 wait_event(bitmap->behind_wait,
1782                            atomic_read(&bitmap->behind_writes) == 0);
1783         }
1784 }
1785
1786 void bitmap_destroy(struct mddev *mddev)
1787 {
1788         struct bitmap *bitmap = mddev->bitmap;
1789
1790         if (!bitmap) /* there was no bitmap */
1791                 return;
1792
1793         bitmap_wait_behind_writes(mddev);
1794
1795         mutex_lock(&mddev->bitmap_info.mutex);
1796         spin_lock(&mddev->lock);
1797         mddev->bitmap = NULL; /* disconnect from the md device */
1798         spin_unlock(&mddev->lock);
1799         mutex_unlock(&mddev->bitmap_info.mutex);
1800         if (mddev->thread)
1801                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1802
1803         bitmap_free(bitmap);
1804 }
1805
1806 /*
1807  * initialize the bitmap structure
1808  * if this returns an error, bitmap_destroy must be called to do clean up
1809  * once mddev->bitmap is set
1810  */
1811 struct bitmap *bitmap_create(struct mddev *mddev, int slot)
1812 {
1813         struct bitmap *bitmap;
1814         sector_t blocks = mddev->resync_max_sectors;
1815         struct file *file = mddev->bitmap_info.file;
1816         int err;
1817         struct kernfs_node *bm = NULL;
1818
1819         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1820
1821         BUG_ON(file && mddev->bitmap_info.offset);
1822
1823         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
1824                 pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
1825                           mdname(mddev));
1826                 return ERR_PTR(-EBUSY);
1827         }
1828
1829         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1830         if (!bitmap)
1831                 return ERR_PTR(-ENOMEM);
1832
1833         spin_lock_init(&bitmap->counts.lock);
1834         atomic_set(&bitmap->pending_writes, 0);
1835         init_waitqueue_head(&bitmap->write_wait);
1836         init_waitqueue_head(&bitmap->overflow_wait);
1837         init_waitqueue_head(&bitmap->behind_wait);
1838
1839         bitmap->mddev = mddev;
1840         bitmap->cluster_slot = slot;
1841
1842         if (mddev->kobj.sd)
1843                 bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1844         if (bm) {
1845                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1846                 sysfs_put(bm);
1847         } else
1848                 bitmap->sysfs_can_clear = NULL;
1849
1850         bitmap->storage.file = file;
1851         if (file) {
1852                 get_file(file);
1853                 /* As future accesses to this file will use bmap,
1854                  * and bypass the page cache, we must sync the file
1855                  * first.
1856                  */
1857                 vfs_fsync(file, 1);
1858         }
1859         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1860         if (!mddev->bitmap_info.external) {
1861                 /*
1862                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1863                  * instructing us to create a new on-disk bitmap instance.
1864                  */
1865                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1866                         err = bitmap_new_disk_sb(bitmap);
1867                 else
1868                         err = bitmap_read_sb(bitmap);
1869         } else {
1870                 err = 0;
1871                 if (mddev->bitmap_info.chunksize == 0 ||
1872                     mddev->bitmap_info.daemon_sleep == 0)
1873                         /* chunksize and time_base need to be
1874                          * set first. */
1875                         err = -EINVAL;
1876         }
1877         if (err)
1878                 goto error;
1879
1880         bitmap->daemon_lastrun = jiffies;
1881         err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1882         if (err)
1883                 goto error;
1884
1885         pr_debug("created bitmap (%lu pages) for device %s\n",
1886                  bitmap->counts.pages, bmname(bitmap));
1887
1888         err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1889         if (err)
1890                 goto error;
1891
1892         return bitmap;
1893  error:
1894         bitmap_free(bitmap);
1895         return ERR_PTR(err);
1896 }
1897
1898 int bitmap_load(struct mddev *mddev)
1899 {
1900         int err = 0;
1901         sector_t start = 0;
1902         sector_t sector = 0;
1903         struct bitmap *bitmap = mddev->bitmap;
1904
1905         if (!bitmap)
1906                 goto out;
1907
1908         if (mddev_is_clustered(mddev))
1909                 md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1910
1911         /* Clear out old bitmap info first:  Either there is none, or we
1912          * are resuming after someone else has possibly changed things,
1913          * so we should forget old cached info.
1914          * All chunks should be clean, but some might need_sync.
1915          */
1916         while (sector < mddev->resync_max_sectors) {
1917                 sector_t blocks;
1918                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1919                 sector += blocks;
1920         }
1921         bitmap_close_sync(bitmap);
1922
1923         if (mddev->degraded == 0
1924             || bitmap->events_cleared == mddev->events)
1925                 /* no need to keep dirty bits to optimise a
1926                  * re-add of a missing device */
1927                 start = mddev->recovery_cp;
1928
1929         mutex_lock(&mddev->bitmap_info.mutex);
1930         err = bitmap_init_from_disk(bitmap, start);
1931         mutex_unlock(&mddev->bitmap_info.mutex);
1932
1933         if (err)
1934                 goto out;
1935         clear_bit(BITMAP_STALE, &bitmap->flags);
1936
1937         /* Kick recovery in case any bits were set */
1938         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1939
1940         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1941         md_wakeup_thread(mddev->thread);
1942
1943         bitmap_update_sb(bitmap);
1944
1945         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1946                 err = -EIO;
1947 out:
1948         return err;
1949 }
1950 EXPORT_SYMBOL_GPL(bitmap_load);
1951
1952 struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
1953 {
1954         int rv = 0;
1955         struct bitmap *bitmap;
1956
1957         bitmap = bitmap_create(mddev, slot);
1958         if (IS_ERR(bitmap)) {
1959                 rv = PTR_ERR(bitmap);
1960                 return ERR_PTR(rv);
1961         }
1962
1963         rv = bitmap_init_from_disk(bitmap, 0);
1964         if (rv) {
1965                 bitmap_free(bitmap);
1966                 return ERR_PTR(rv);
1967         }
1968
1969         return bitmap;
1970 }
1971 EXPORT_SYMBOL(get_bitmap_from_slot);
1972
1973 /* Loads the bitmap associated with slot and copies the resync information
1974  * to our bitmap
1975  */
1976 int bitmap_copy_from_slot(struct mddev *mddev, int slot,
1977                 sector_t *low, sector_t *high, bool clear_bits)
1978 {
1979         int rv = 0, i, j;
1980         sector_t block, lo = 0, hi = 0;
1981         struct bitmap_counts *counts;
1982         struct bitmap *bitmap;
1983
1984         bitmap = get_bitmap_from_slot(mddev, slot);
1985         if (IS_ERR(bitmap)) {
1986                 pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
1987                 return -1;
1988         }
1989
1990         counts = &bitmap->counts;
1991         for (j = 0; j < counts->chunks; j++) {
1992                 block = (sector_t)j << counts->chunkshift;
1993                 if (bitmap_file_test_bit(bitmap, block)) {
1994                         if (!lo)
1995                                 lo = block;
1996                         hi = block;
1997                         bitmap_file_clear_bit(bitmap, block);
1998                         bitmap_set_memory_bits(mddev->bitmap, block, 1);
1999                         bitmap_file_set_bit(mddev->bitmap, block);
2000                 }
2001         }
2002
2003         if (clear_bits) {
2004                 bitmap_update_sb(bitmap);
2005                 /* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
2006                  * BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
2007                 for (i = 0; i < bitmap->storage.file_pages; i++)
2008                         if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
2009                                 set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
2010                 bitmap_unplug(bitmap);
2011         }
2012         bitmap_unplug(mddev->bitmap);
2013         *low = lo;
2014         *high = hi;
2015
2016         return rv;
2017 }
2018 EXPORT_SYMBOL_GPL(bitmap_copy_from_slot);
2019
2020
2021 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2022 {
2023         unsigned long chunk_kb;
2024         struct bitmap_counts *counts;
2025
2026         if (!bitmap)
2027                 return;
2028
2029         counts = &bitmap->counts;
2030
2031         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2032         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2033                    "%lu%s chunk",
2034                    counts->pages - counts->missing_pages,
2035                    counts->pages,
2036                    (counts->pages - counts->missing_pages)
2037                    << (PAGE_SHIFT - 10),
2038                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2039                    chunk_kb ? "KB" : "B");
2040         if (bitmap->storage.file) {
2041                 seq_printf(seq, ", file: ");
2042                 seq_file_path(seq, bitmap->storage.file, " \t\n");
2043         }
2044
2045         seq_printf(seq, "\n");
2046 }
2047
2048 int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2049                   int chunksize, int init)
2050 {
2051         /* If chunk_size is 0, choose an appropriate chunk size.
2052          * Then possibly allocate new storage space.
2053          * Then quiesce, copy bits, replace bitmap, and re-start
2054          *
2055          * This function is called both to set up the initial bitmap
2056          * and to resize the bitmap while the array is active.
2057          * If this happens as a result of the array being resized,
2058          * chunksize will be zero, and we need to choose a suitable
2059          * chunksize, otherwise we use what we are given.
2060          */
2061         struct bitmap_storage store;
2062         struct bitmap_counts old_counts;
2063         unsigned long chunks;
2064         sector_t block;
2065         sector_t old_blocks, new_blocks;
2066         int chunkshift;
2067         int ret = 0;
2068         long pages;
2069         struct bitmap_page *new_bp;
2070
2071         if (bitmap->storage.file && !init) {
2072                 pr_info("md: cannot resize file-based bitmap\n");
2073                 return -EINVAL;
2074         }
2075
2076         if (chunksize == 0) {
2077                 /* If there is enough space, leave the chunk size unchanged,
2078                  * else increase by factor of two until there is enough space.
2079                  */
2080                 long bytes;
2081                 long space = bitmap->mddev->bitmap_info.space;
2082
2083                 if (space == 0) {
2084                         /* We don't know how much space there is, so limit
2085                          * to current size - in sectors.
2086                          */
2087                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2088                         if (!bitmap->mddev->bitmap_info.external)
2089                                 bytes += sizeof(bitmap_super_t);
2090                         space = DIV_ROUND_UP(bytes, 512);
2091                         bitmap->mddev->bitmap_info.space = space;
2092                 }
2093                 chunkshift = bitmap->counts.chunkshift;
2094                 chunkshift--;
2095                 do {
2096                         /* 'chunkshift' is shift from block size to chunk size */
2097                         chunkshift++;
2098                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2099                         bytes = DIV_ROUND_UP(chunks, 8);
2100                         if (!bitmap->mddev->bitmap_info.external)
2101                                 bytes += sizeof(bitmap_super_t);
2102                 } while (bytes > (space << 9));
2103         } else
2104                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2105
2106         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2107         memset(&store, 0, sizeof(store));
2108         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2109                 ret = bitmap_storage_alloc(&store, chunks,
2110                                            !bitmap->mddev->bitmap_info.external,
2111                                            mddev_is_clustered(bitmap->mddev)
2112                                            ? bitmap->cluster_slot : 0);
2113         if (ret) {
2114                 bitmap_file_unmap(&store);
2115                 goto err;
2116         }
2117
2118         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2119
2120         new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
2121         ret = -ENOMEM;
2122         if (!new_bp) {
2123                 bitmap_file_unmap(&store);
2124                 goto err;
2125         }
2126
2127         if (!init)
2128                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2129
2130         store.file = bitmap->storage.file;
2131         bitmap->storage.file = NULL;
2132
2133         if (store.sb_page && bitmap->storage.sb_page)
2134                 memcpy(page_address(store.sb_page),
2135                        page_address(bitmap->storage.sb_page),
2136                        sizeof(bitmap_super_t));
2137         bitmap_file_unmap(&bitmap->storage);
2138         bitmap->storage = store;
2139
2140         old_counts = bitmap->counts;
2141         bitmap->counts.bp = new_bp;
2142         bitmap->counts.pages = pages;
2143         bitmap->counts.missing_pages = pages;
2144         bitmap->counts.chunkshift = chunkshift;
2145         bitmap->counts.chunks = chunks;
2146         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2147                                                      BITMAP_BLOCK_SHIFT);
2148
2149         blocks = min(old_counts.chunks << old_counts.chunkshift,
2150                      chunks << chunkshift);
2151
2152         spin_lock_irq(&bitmap->counts.lock);
2153         /* For cluster raid, need to pre-allocate bitmap */
2154         if (mddev_is_clustered(bitmap->mddev)) {
2155                 unsigned long page;
2156                 for (page = 0; page < pages; page++) {
2157                         ret = bitmap_checkpage(&bitmap->counts, page, 1, 1);
2158                         if (ret) {
2159                                 unsigned long k;
2160
2161                                 /* deallocate the page memory */
2162                                 for (k = 0; k < page; k++) {
2163                                         kfree(new_bp[k].map);
2164                                 }
2165
2166                                 /* restore some fields from old_counts */
2167                                 bitmap->counts.bp = old_counts.bp;
2168                                 bitmap->counts.pages = old_counts.pages;
2169                                 bitmap->counts.missing_pages = old_counts.pages;
2170                                 bitmap->counts.chunkshift = old_counts.chunkshift;
2171                                 bitmap->counts.chunks = old_counts.chunks;
2172                                 bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
2173                                                                              BITMAP_BLOCK_SHIFT);
2174                                 blocks = old_counts.chunks << old_counts.chunkshift;
2175                                 pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2176                                 break;
2177                         } else
2178                                 bitmap->counts.bp[page].count += 1;
2179                 }
2180         }
2181
2182         for (block = 0; block < blocks; ) {
2183                 bitmap_counter_t *bmc_old, *bmc_new;
2184                 int set;
2185
2186                 bmc_old = bitmap_get_counter(&old_counts, block,
2187                                              &old_blocks, 0);
2188                 set = bmc_old && NEEDED(*bmc_old);
2189
2190                 if (set) {
2191                         bmc_new = bitmap_get_counter(&bitmap->counts, block,
2192                                                      &new_blocks, 1);
2193                         if (*bmc_new == 0) {
2194                                 /* need to set on-disk bits too. */
2195                                 sector_t end = block + new_blocks;
2196                                 sector_t start = block >> chunkshift;
2197                                 start <<= chunkshift;
2198                                 while (start < end) {
2199                                         bitmap_file_set_bit(bitmap, block);
2200                                         start += 1 << chunkshift;
2201                                 }
2202                                 *bmc_new = 2;
2203                                 bitmap_count_page(&bitmap->counts,
2204                                                   block, 1);
2205                                 bitmap_set_pending(&bitmap->counts,
2206                                                    block);
2207                         }
2208                         *bmc_new |= NEEDED_MASK;
2209                         if (new_blocks < old_blocks)
2210                                 old_blocks = new_blocks;
2211                 }
2212                 block += old_blocks;
2213         }
2214
2215         if (!init) {
2216                 int i;
2217                 while (block < (chunks << chunkshift)) {
2218                         bitmap_counter_t *bmc;
2219                         bmc = bitmap_get_counter(&bitmap->counts, block,
2220                                                  &new_blocks, 1);
2221                         if (bmc) {
2222                                 /* new space.  It needs to be resynced, so
2223                                  * we set NEEDED_MASK.
2224                                  */
2225                                 if (*bmc == 0) {
2226                                         *bmc = NEEDED_MASK | 2;
2227                                         bitmap_count_page(&bitmap->counts,
2228                                                           block, 1);
2229                                         bitmap_set_pending(&bitmap->counts,
2230                                                            block);
2231                                 }
2232                         }
2233                         block += new_blocks;
2234                 }
2235                 for (i = 0; i < bitmap->storage.file_pages; i++)
2236                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
2237         }
2238         spin_unlock_irq(&bitmap->counts.lock);
2239
2240         if (!init) {
2241                 bitmap_unplug(bitmap);
2242                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2243         }
2244         ret = 0;
2245 err:
2246         return ret;
2247 }
2248 EXPORT_SYMBOL_GPL(bitmap_resize);
2249
2250 static ssize_t
2251 location_show(struct mddev *mddev, char *page)
2252 {
2253         ssize_t len;
2254         if (mddev->bitmap_info.file)
2255                 len = sprintf(page, "file");
2256         else if (mddev->bitmap_info.offset)
2257                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
2258         else
2259                 len = sprintf(page, "none");
2260         len += sprintf(page+len, "\n");
2261         return len;
2262 }
2263
2264 static ssize_t
2265 location_store(struct mddev *mddev, const char *buf, size_t len)
2266 {
2267         int rv;
2268
2269         rv = mddev_lock(mddev);
2270         if (rv)
2271                 return rv;
2272         if (mddev->pers) {
2273                 if (!mddev->pers->quiesce) {
2274                         rv = -EBUSY;
2275                         goto out;
2276                 }
2277                 if (mddev->recovery || mddev->sync_thread) {
2278                         rv = -EBUSY;
2279                         goto out;
2280                 }
2281         }
2282
2283         if (mddev->bitmap || mddev->bitmap_info.file ||
2284             mddev->bitmap_info.offset) {
2285                 /* bitmap already configured.  Only option is to clear it */
2286                 if (strncmp(buf, "none", 4) != 0) {
2287                         rv = -EBUSY;
2288                         goto out;
2289                 }
2290                 if (mddev->pers) {
2291                         mddev->pers->quiesce(mddev, 1);
2292                         bitmap_destroy(mddev);
2293                         mddev->pers->quiesce(mddev, 0);
2294                 }
2295                 mddev->bitmap_info.offset = 0;
2296                 if (mddev->bitmap_info.file) {
2297                         struct file *f = mddev->bitmap_info.file;
2298                         mddev->bitmap_info.file = NULL;
2299                         fput(f);
2300                 }
2301         } else {
2302                 /* No bitmap, OK to set a location */
2303                 long long offset;
2304                 if (strncmp(buf, "none", 4) == 0)
2305                         /* nothing to be done */;
2306                 else if (strncmp(buf, "file:", 5) == 0) {
2307                         /* Not supported yet */
2308                         rv = -EINVAL;
2309                         goto out;
2310                 } else {
2311                         if (buf[0] == '+')
2312                                 rv = kstrtoll(buf+1, 10, &offset);
2313                         else
2314                                 rv = kstrtoll(buf, 10, &offset);
2315                         if (rv)
2316                                 goto out;
2317                         if (offset == 0) {
2318                                 rv = -EINVAL;
2319                                 goto out;
2320                         }
2321                         if (mddev->bitmap_info.external == 0 &&
2322                             mddev->major_version == 0 &&
2323                             offset != mddev->bitmap_info.default_offset) {
2324                                 rv = -EINVAL;
2325                                 goto out;
2326                         }
2327                         mddev->bitmap_info.offset = offset;
2328                         if (mddev->pers) {
2329                                 struct bitmap *bitmap;
2330                                 mddev->pers->quiesce(mddev, 1);
2331                                 bitmap = bitmap_create(mddev, -1);
2332                                 if (IS_ERR(bitmap))
2333                                         rv = PTR_ERR(bitmap);
2334                                 else {
2335                                         mddev->bitmap = bitmap;
2336                                         rv = bitmap_load(mddev);
2337                                         if (rv)
2338                                                 mddev->bitmap_info.offset = 0;
2339                                 }
2340                                 mddev->pers->quiesce(mddev, 0);
2341                                 if (rv) {
2342                                         bitmap_destroy(mddev);
2343                                         goto out;
2344                                 }
2345                         }
2346                 }
2347         }
2348         if (!mddev->external) {
2349                 /* Ensure new bitmap info is stored in
2350                  * metadata promptly.
2351                  */
2352                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2353                 md_wakeup_thread(mddev->thread);
2354         }
2355         rv = 0;
2356 out:
2357         mddev_unlock(mddev);
2358         if (rv)
2359                 return rv;
2360         return len;
2361 }
2362
2363 static struct md_sysfs_entry bitmap_location =
2364 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2365
2366 /* 'bitmap/space' is the space available at 'location' for the
2367  * bitmap.  This allows the kernel to know when it is safe to
2368  * resize the bitmap to match a resized array.
2369  */
2370 static ssize_t
2371 space_show(struct mddev *mddev, char *page)
2372 {
2373         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2374 }
2375
2376 static ssize_t
2377 space_store(struct mddev *mddev, const char *buf, size_t len)
2378 {
2379         unsigned long sectors;
2380         int rv;
2381
2382         rv = kstrtoul(buf, 10, &sectors);
2383         if (rv)
2384                 return rv;
2385
2386         if (sectors == 0)
2387                 return -EINVAL;
2388
2389         if (mddev->bitmap &&
2390             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2391                 return -EFBIG; /* Bitmap is too big for this small space */
2392
2393         /* could make sure it isn't too big, but that isn't really
2394          * needed - user-space should be careful.
2395          */
2396         mddev->bitmap_info.space = sectors;
2397         return len;
2398 }
2399
2400 static struct md_sysfs_entry bitmap_space =
2401 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2402
2403 static ssize_t
2404 timeout_show(struct mddev *mddev, char *page)
2405 {
2406         ssize_t len;
2407         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2408         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2409
2410         len = sprintf(page, "%lu", secs);
2411         if (jifs)
2412                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2413         len += sprintf(page+len, "\n");
2414         return len;
2415 }
2416
2417 static ssize_t
2418 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2419 {
2420         /* timeout can be set at any time */
2421         unsigned long timeout;
2422         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2423         if (rv)
2424                 return rv;
2425
2426         /* just to make sure we don't overflow... */
2427         if (timeout >= LONG_MAX / HZ)
2428                 return -EINVAL;
2429
2430         timeout = timeout * HZ / 10000;
2431
2432         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2433                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2434         if (timeout < 1)
2435                 timeout = 1;
2436         mddev->bitmap_info.daemon_sleep = timeout;
2437         if (mddev->thread) {
2438                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2439                  * the bitmap is all clean and we don't need to
2440                  * adjust the timeout right now
2441                  */
2442                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2443                         mddev->thread->timeout = timeout;
2444                         md_wakeup_thread(mddev->thread);
2445                 }
2446         }
2447         return len;
2448 }
2449
2450 static struct md_sysfs_entry bitmap_timeout =
2451 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2452
2453 static ssize_t
2454 backlog_show(struct mddev *mddev, char *page)
2455 {
2456         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2457 }
2458
2459 static ssize_t
2460 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2461 {
2462         unsigned long backlog;
2463         int rv = kstrtoul(buf, 10, &backlog);
2464         if (rv)
2465                 return rv;
2466         if (backlog > COUNTER_MAX)
2467                 return -EINVAL;
2468         mddev->bitmap_info.max_write_behind = backlog;
2469         return len;
2470 }
2471
2472 static struct md_sysfs_entry bitmap_backlog =
2473 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2474
2475 static ssize_t
2476 chunksize_show(struct mddev *mddev, char *page)
2477 {
2478         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2479 }
2480
2481 static ssize_t
2482 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2483 {
2484         /* Can only be changed when no bitmap is active */
2485         int rv;
2486         unsigned long csize;
2487         if (mddev->bitmap)
2488                 return -EBUSY;
2489         rv = kstrtoul(buf, 10, &csize);
2490         if (rv)
2491                 return rv;
2492         if (csize < 512 ||
2493             !is_power_of_2(csize))
2494                 return -EINVAL;
2495         mddev->bitmap_info.chunksize = csize;
2496         return len;
2497 }
2498
2499 static struct md_sysfs_entry bitmap_chunksize =
2500 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2501
2502 static ssize_t metadata_show(struct mddev *mddev, char *page)
2503 {
2504         if (mddev_is_clustered(mddev))
2505                 return sprintf(page, "clustered\n");
2506         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2507                                       ? "external" : "internal"));
2508 }
2509
2510 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2511 {
2512         if (mddev->bitmap ||
2513             mddev->bitmap_info.file ||
2514             mddev->bitmap_info.offset)
2515                 return -EBUSY;
2516         if (strncmp(buf, "external", 8) == 0)
2517                 mddev->bitmap_info.external = 1;
2518         else if ((strncmp(buf, "internal", 8) == 0) ||
2519                         (strncmp(buf, "clustered", 9) == 0))
2520                 mddev->bitmap_info.external = 0;
2521         else
2522                 return -EINVAL;
2523         return len;
2524 }
2525
2526 static struct md_sysfs_entry bitmap_metadata =
2527 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2528
2529 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2530 {
2531         int len;
2532         spin_lock(&mddev->lock);
2533         if (mddev->bitmap)
2534                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2535                                              "false" : "true"));
2536         else
2537                 len = sprintf(page, "\n");
2538         spin_unlock(&mddev->lock);
2539         return len;
2540 }
2541
2542 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2543 {
2544         if (mddev->bitmap == NULL)
2545                 return -ENOENT;
2546         if (strncmp(buf, "false", 5) == 0)
2547                 mddev->bitmap->need_sync = 1;
2548         else if (strncmp(buf, "true", 4) == 0) {
2549                 if (mddev->degraded)
2550                         return -EBUSY;
2551                 mddev->bitmap->need_sync = 0;
2552         } else
2553                 return -EINVAL;
2554         return len;
2555 }
2556
2557 static struct md_sysfs_entry bitmap_can_clear =
2558 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2559
2560 static ssize_t
2561 behind_writes_used_show(struct mddev *mddev, char *page)
2562 {
2563         ssize_t ret;
2564         spin_lock(&mddev->lock);
2565         if (mddev->bitmap == NULL)
2566                 ret = sprintf(page, "0\n");
2567         else
2568                 ret = sprintf(page, "%lu\n",
2569                               mddev->bitmap->behind_writes_used);
2570         spin_unlock(&mddev->lock);
2571         return ret;
2572 }
2573
2574 static ssize_t
2575 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2576 {
2577         if (mddev->bitmap)
2578                 mddev->bitmap->behind_writes_used = 0;
2579         return len;
2580 }
2581
2582 static struct md_sysfs_entry max_backlog_used =
2583 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2584        behind_writes_used_show, behind_writes_used_reset);
2585
2586 static struct attribute *md_bitmap_attrs[] = {
2587         &bitmap_location.attr,
2588         &bitmap_space.attr,
2589         &bitmap_timeout.attr,
2590         &bitmap_backlog.attr,
2591         &bitmap_chunksize.attr,
2592         &bitmap_metadata.attr,
2593         &bitmap_can_clear.attr,
2594         &max_backlog_used.attr,
2595         NULL
2596 };
2597 struct attribute_group md_bitmap_group = {
2598         .name = "bitmap",
2599         .attrs = md_bitmap_attrs,
2600 };
2601