xref: /openbmc/linux/drivers/md/md-bitmap.c (revision 023e4163)
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 md_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 md_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 md_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 		md_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, false);
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  * md_bitmap_wait_writes() should be called before writing any bitmap
425  * blocks, to ensure previous writes, particularly from
426  * md_bitmap_daemon_work(), have completed.
427  */
428 static void md_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 md_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(md_bitmap_update_sb);
480 
481 /* print out the bitmap file superblock */
482 void md_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 md_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 md_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 		md_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 md_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_array(num_pages, sizeof(struct page *),
793 				       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 md_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 md_bitmap_file_kick(struct bitmap *bitmap)
866 {
867 	char *path, *ptr = NULL;
868 
869 	if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
870 		md_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 md_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 md_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 md_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 md_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 				md_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 		md_bitmap_wait_writes(bitmap);
1040 
1041 	if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1042 		md_bitmap_file_kick(bitmap);
1043 }
1044 EXPORT_SYMBOL(md_bitmap_unplug);
1045 
1046 static void md_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 md_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 			md_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 			md_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 md_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 md_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 	md_bitmap_checkfree(bitmap, page);
1208 }
1209 
1210 static void md_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 *md_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 md_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 
1305 		bmc = md_bitmap_get_counter(counts, block, &blocks, 0);
1306 		if (!bmc) {
1307 			j |= PAGE_COUNTER_MASK;
1308 			continue;
1309 		}
1310 		if (*bmc == 1 && !bitmap->need_sync) {
1311 			/* We can clear the bit */
1312 			*bmc = 0;
1313 			md_bitmap_count_page(counts, block, -1);
1314 			md_bitmap_file_clear_bit(bitmap, block);
1315 		} else if (*bmc && *bmc <= 2) {
1316 			*bmc = 1;
1317 			md_bitmap_set_pending(counts, block);
1318 			bitmap->allclean = 0;
1319 		}
1320 	}
1321 	spin_unlock_irq(&counts->lock);
1322 
1323 	md_bitmap_wait_writes(bitmap);
1324 	/* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1325 	 * DIRTY pages need to be written by bitmap_unplug so it can wait
1326 	 * for them.
1327 	 * If we find any DIRTY page we stop there and let bitmap_unplug
1328 	 * handle all the rest.  This is important in the case where
1329 	 * the first blocking holds the superblock and it has been updated.
1330 	 * We mustn't write any other blocks before the superblock.
1331 	 */
1332 	for (j = 0;
1333 	     j < bitmap->storage.file_pages
1334 		     && !test_bit(BITMAP_STALE, &bitmap->flags);
1335 	     j++) {
1336 		if (test_page_attr(bitmap, j,
1337 				   BITMAP_PAGE_DIRTY))
1338 			/* bitmap_unplug will handle the rest */
1339 			break;
1340 		if (test_and_clear_page_attr(bitmap, j,
1341 					     BITMAP_PAGE_NEEDWRITE)) {
1342 			write_page(bitmap, bitmap->storage.filemap[j], 0);
1343 		}
1344 	}
1345 
1346  done:
1347 	if (bitmap->allclean == 0)
1348 		mddev->thread->timeout =
1349 			mddev->bitmap_info.daemon_sleep;
1350 	mutex_unlock(&mddev->bitmap_info.mutex);
1351 }
1352 
1353 static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1354 					       sector_t offset, sector_t *blocks,
1355 					       int create)
1356 __releases(bitmap->lock)
1357 __acquires(bitmap->lock)
1358 {
1359 	/* If 'create', we might release the lock and reclaim it.
1360 	 * The lock must have been taken with interrupts enabled.
1361 	 * If !create, we don't release the lock.
1362 	 */
1363 	sector_t chunk = offset >> bitmap->chunkshift;
1364 	unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1365 	unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1366 	sector_t csize;
1367 	int err;
1368 
1369 	err = md_bitmap_checkpage(bitmap, page, create, 0);
1370 
1371 	if (bitmap->bp[page].hijacked ||
1372 	    bitmap->bp[page].map == NULL)
1373 		csize = ((sector_t)1) << (bitmap->chunkshift +
1374 					  PAGE_COUNTER_SHIFT - 1);
1375 	else
1376 		csize = ((sector_t)1) << bitmap->chunkshift;
1377 	*blocks = csize - (offset & (csize - 1));
1378 
1379 	if (err < 0)
1380 		return NULL;
1381 
1382 	/* now locked ... */
1383 
1384 	if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1385 		/* should we use the first or second counter field
1386 		 * of the hijacked pointer? */
1387 		int hi = (pageoff > PAGE_COUNTER_MASK);
1388 		return  &((bitmap_counter_t *)
1389 			  &bitmap->bp[page].map)[hi];
1390 	} else /* page is allocated */
1391 		return (bitmap_counter_t *)
1392 			&(bitmap->bp[page].map[pageoff]);
1393 }
1394 
1395 int md_bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1396 {
1397 	if (!bitmap)
1398 		return 0;
1399 
1400 	if (behind) {
1401 		int bw;
1402 		atomic_inc(&bitmap->behind_writes);
1403 		bw = atomic_read(&bitmap->behind_writes);
1404 		if (bw > bitmap->behind_writes_used)
1405 			bitmap->behind_writes_used = bw;
1406 
1407 		pr_debug("inc write-behind count %d/%lu\n",
1408 			 bw, bitmap->mddev->bitmap_info.max_write_behind);
1409 	}
1410 
1411 	while (sectors) {
1412 		sector_t blocks;
1413 		bitmap_counter_t *bmc;
1414 
1415 		spin_lock_irq(&bitmap->counts.lock);
1416 		bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1417 		if (!bmc) {
1418 			spin_unlock_irq(&bitmap->counts.lock);
1419 			return 0;
1420 		}
1421 
1422 		if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1423 			DEFINE_WAIT(__wait);
1424 			/* note that it is safe to do the prepare_to_wait
1425 			 * after the test as long as we do it before dropping
1426 			 * the spinlock.
1427 			 */
1428 			prepare_to_wait(&bitmap->overflow_wait, &__wait,
1429 					TASK_UNINTERRUPTIBLE);
1430 			spin_unlock_irq(&bitmap->counts.lock);
1431 			schedule();
1432 			finish_wait(&bitmap->overflow_wait, &__wait);
1433 			continue;
1434 		}
1435 
1436 		switch (*bmc) {
1437 		case 0:
1438 			md_bitmap_file_set_bit(bitmap, offset);
1439 			md_bitmap_count_page(&bitmap->counts, offset, 1);
1440 			/* fall through */
1441 		case 1:
1442 			*bmc = 2;
1443 		}
1444 
1445 		(*bmc)++;
1446 
1447 		spin_unlock_irq(&bitmap->counts.lock);
1448 
1449 		offset += blocks;
1450 		if (sectors > blocks)
1451 			sectors -= blocks;
1452 		else
1453 			sectors = 0;
1454 	}
1455 	return 0;
1456 }
1457 EXPORT_SYMBOL(md_bitmap_startwrite);
1458 
1459 void md_bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
1460 			unsigned long sectors, int success, int behind)
1461 {
1462 	if (!bitmap)
1463 		return;
1464 	if (behind) {
1465 		if (atomic_dec_and_test(&bitmap->behind_writes))
1466 			wake_up(&bitmap->behind_wait);
1467 		pr_debug("dec write-behind count %d/%lu\n",
1468 			 atomic_read(&bitmap->behind_writes),
1469 			 bitmap->mddev->bitmap_info.max_write_behind);
1470 	}
1471 
1472 	while (sectors) {
1473 		sector_t blocks;
1474 		unsigned long flags;
1475 		bitmap_counter_t *bmc;
1476 
1477 		spin_lock_irqsave(&bitmap->counts.lock, flags);
1478 		bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1479 		if (!bmc) {
1480 			spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1481 			return;
1482 		}
1483 
1484 		if (success && !bitmap->mddev->degraded &&
1485 		    bitmap->events_cleared < bitmap->mddev->events) {
1486 			bitmap->events_cleared = bitmap->mddev->events;
1487 			bitmap->need_sync = 1;
1488 			sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1489 		}
1490 
1491 		if (!success && !NEEDED(*bmc))
1492 			*bmc |= NEEDED_MASK;
1493 
1494 		if (COUNTER(*bmc) == COUNTER_MAX)
1495 			wake_up(&bitmap->overflow_wait);
1496 
1497 		(*bmc)--;
1498 		if (*bmc <= 2) {
1499 			md_bitmap_set_pending(&bitmap->counts, offset);
1500 			bitmap->allclean = 0;
1501 		}
1502 		spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1503 		offset += blocks;
1504 		if (sectors > blocks)
1505 			sectors -= blocks;
1506 		else
1507 			sectors = 0;
1508 	}
1509 }
1510 EXPORT_SYMBOL(md_bitmap_endwrite);
1511 
1512 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1513 			       int degraded)
1514 {
1515 	bitmap_counter_t *bmc;
1516 	int rv;
1517 	if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1518 		*blocks = 1024;
1519 		return 1; /* always resync if no bitmap */
1520 	}
1521 	spin_lock_irq(&bitmap->counts.lock);
1522 	bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1523 	rv = 0;
1524 	if (bmc) {
1525 		/* locked */
1526 		if (RESYNC(*bmc))
1527 			rv = 1;
1528 		else if (NEEDED(*bmc)) {
1529 			rv = 1;
1530 			if (!degraded) { /* don't set/clear bits if degraded */
1531 				*bmc |= RESYNC_MASK;
1532 				*bmc &= ~NEEDED_MASK;
1533 			}
1534 		}
1535 	}
1536 	spin_unlock_irq(&bitmap->counts.lock);
1537 	return rv;
1538 }
1539 
1540 int md_bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1541 			 int degraded)
1542 {
1543 	/* bitmap_start_sync must always report on multiples of whole
1544 	 * pages, otherwise resync (which is very PAGE_SIZE based) will
1545 	 * get confused.
1546 	 * So call __bitmap_start_sync repeatedly (if needed) until
1547 	 * At least PAGE_SIZE>>9 blocks are covered.
1548 	 * Return the 'or' of the result.
1549 	 */
1550 	int rv = 0;
1551 	sector_t blocks1;
1552 
1553 	*blocks = 0;
1554 	while (*blocks < (PAGE_SIZE>>9)) {
1555 		rv |= __bitmap_start_sync(bitmap, offset,
1556 					  &blocks1, degraded);
1557 		offset += blocks1;
1558 		*blocks += blocks1;
1559 	}
1560 	return rv;
1561 }
1562 EXPORT_SYMBOL(md_bitmap_start_sync);
1563 
1564 void md_bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1565 {
1566 	bitmap_counter_t *bmc;
1567 	unsigned long flags;
1568 
1569 	if (bitmap == NULL) {
1570 		*blocks = 1024;
1571 		return;
1572 	}
1573 	spin_lock_irqsave(&bitmap->counts.lock, flags);
1574 	bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1575 	if (bmc == NULL)
1576 		goto unlock;
1577 	/* locked */
1578 	if (RESYNC(*bmc)) {
1579 		*bmc &= ~RESYNC_MASK;
1580 
1581 		if (!NEEDED(*bmc) && aborted)
1582 			*bmc |= NEEDED_MASK;
1583 		else {
1584 			if (*bmc <= 2) {
1585 				md_bitmap_set_pending(&bitmap->counts, offset);
1586 				bitmap->allclean = 0;
1587 			}
1588 		}
1589 	}
1590  unlock:
1591 	spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1592 }
1593 EXPORT_SYMBOL(md_bitmap_end_sync);
1594 
1595 void md_bitmap_close_sync(struct bitmap *bitmap)
1596 {
1597 	/* Sync has finished, and any bitmap chunks that weren't synced
1598 	 * properly have been aborted.  It remains to us to clear the
1599 	 * RESYNC bit wherever it is still on
1600 	 */
1601 	sector_t sector = 0;
1602 	sector_t blocks;
1603 	if (!bitmap)
1604 		return;
1605 	while (sector < bitmap->mddev->resync_max_sectors) {
1606 		md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1607 		sector += blocks;
1608 	}
1609 }
1610 EXPORT_SYMBOL(md_bitmap_close_sync);
1611 
1612 void md_bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
1613 {
1614 	sector_t s = 0;
1615 	sector_t blocks;
1616 
1617 	if (!bitmap)
1618 		return;
1619 	if (sector == 0) {
1620 		bitmap->last_end_sync = jiffies;
1621 		return;
1622 	}
1623 	if (!force && time_before(jiffies, (bitmap->last_end_sync
1624 				  + bitmap->mddev->bitmap_info.daemon_sleep)))
1625 		return;
1626 	wait_event(bitmap->mddev->recovery_wait,
1627 		   atomic_read(&bitmap->mddev->recovery_active) == 0);
1628 
1629 	bitmap->mddev->curr_resync_completed = sector;
1630 	set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
1631 	sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1632 	s = 0;
1633 	while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1634 		md_bitmap_end_sync(bitmap, s, &blocks, 0);
1635 		s += blocks;
1636 	}
1637 	bitmap->last_end_sync = jiffies;
1638 	sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1639 }
1640 EXPORT_SYMBOL(md_bitmap_cond_end_sync);
1641 
1642 void md_bitmap_sync_with_cluster(struct mddev *mddev,
1643 			      sector_t old_lo, sector_t old_hi,
1644 			      sector_t new_lo, sector_t new_hi)
1645 {
1646 	struct bitmap *bitmap = mddev->bitmap;
1647 	sector_t sector, blocks = 0;
1648 
1649 	for (sector = old_lo; sector < new_lo; ) {
1650 		md_bitmap_end_sync(bitmap, sector, &blocks, 0);
1651 		sector += blocks;
1652 	}
1653 	WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1654 
1655 	for (sector = old_hi; sector < new_hi; ) {
1656 		md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1657 		sector += blocks;
1658 	}
1659 	WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1660 }
1661 EXPORT_SYMBOL(md_bitmap_sync_with_cluster);
1662 
1663 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1664 {
1665 	/* For each chunk covered by any of these sectors, set the
1666 	 * counter to 2 and possibly set resync_needed.  They should all
1667 	 * be 0 at this point
1668 	 */
1669 
1670 	sector_t secs;
1671 	bitmap_counter_t *bmc;
1672 	spin_lock_irq(&bitmap->counts.lock);
1673 	bmc = md_bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1674 	if (!bmc) {
1675 		spin_unlock_irq(&bitmap->counts.lock);
1676 		return;
1677 	}
1678 	if (!*bmc) {
1679 		*bmc = 2;
1680 		md_bitmap_count_page(&bitmap->counts, offset, 1);
1681 		md_bitmap_set_pending(&bitmap->counts, offset);
1682 		bitmap->allclean = 0;
1683 	}
1684 	if (needed)
1685 		*bmc |= NEEDED_MASK;
1686 	spin_unlock_irq(&bitmap->counts.lock);
1687 }
1688 
1689 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1690 void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1691 {
1692 	unsigned long chunk;
1693 
1694 	for (chunk = s; chunk <= e; chunk++) {
1695 		sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1696 		md_bitmap_set_memory_bits(bitmap, sec, 1);
1697 		md_bitmap_file_set_bit(bitmap, sec);
1698 		if (sec < bitmap->mddev->recovery_cp)
1699 			/* We are asserting that the array is dirty,
1700 			 * so move the recovery_cp address back so
1701 			 * that it is obvious that it is dirty
1702 			 */
1703 			bitmap->mddev->recovery_cp = sec;
1704 	}
1705 }
1706 
1707 /*
1708  * flush out any pending updates
1709  */
1710 void md_bitmap_flush(struct mddev *mddev)
1711 {
1712 	struct bitmap *bitmap = mddev->bitmap;
1713 	long sleep;
1714 
1715 	if (!bitmap) /* there was no bitmap */
1716 		return;
1717 
1718 	/* run the daemon_work three time to ensure everything is flushed
1719 	 * that can be
1720 	 */
1721 	sleep = mddev->bitmap_info.daemon_sleep * 2;
1722 	bitmap->daemon_lastrun -= sleep;
1723 	md_bitmap_daemon_work(mddev);
1724 	bitmap->daemon_lastrun -= sleep;
1725 	md_bitmap_daemon_work(mddev);
1726 	bitmap->daemon_lastrun -= sleep;
1727 	md_bitmap_daemon_work(mddev);
1728 	md_bitmap_update_sb(bitmap);
1729 }
1730 
1731 /*
1732  * free memory that was allocated
1733  */
1734 void md_bitmap_free(struct bitmap *bitmap)
1735 {
1736 	unsigned long k, pages;
1737 	struct bitmap_page *bp;
1738 
1739 	if (!bitmap) /* there was no bitmap */
1740 		return;
1741 
1742 	if (bitmap->sysfs_can_clear)
1743 		sysfs_put(bitmap->sysfs_can_clear);
1744 
1745 	if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
1746 		bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
1747 		md_cluster_stop(bitmap->mddev);
1748 
1749 	/* Shouldn't be needed - but just in case.... */
1750 	wait_event(bitmap->write_wait,
1751 		   atomic_read(&bitmap->pending_writes) == 0);
1752 
1753 	/* release the bitmap file  */
1754 	md_bitmap_file_unmap(&bitmap->storage);
1755 
1756 	bp = bitmap->counts.bp;
1757 	pages = bitmap->counts.pages;
1758 
1759 	/* free all allocated memory */
1760 
1761 	if (bp) /* deallocate the page memory */
1762 		for (k = 0; k < pages; k++)
1763 			if (bp[k].map && !bp[k].hijacked)
1764 				kfree(bp[k].map);
1765 	kfree(bp);
1766 	kfree(bitmap);
1767 }
1768 EXPORT_SYMBOL(md_bitmap_free);
1769 
1770 void md_bitmap_wait_behind_writes(struct mddev *mddev)
1771 {
1772 	struct bitmap *bitmap = mddev->bitmap;
1773 
1774 	/* wait for behind writes to complete */
1775 	if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1776 		pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
1777 			 mdname(mddev));
1778 		/* need to kick something here to make sure I/O goes? */
1779 		wait_event(bitmap->behind_wait,
1780 			   atomic_read(&bitmap->behind_writes) == 0);
1781 	}
1782 }
1783 
1784 void md_bitmap_destroy(struct mddev *mddev)
1785 {
1786 	struct bitmap *bitmap = mddev->bitmap;
1787 
1788 	if (!bitmap) /* there was no bitmap */
1789 		return;
1790 
1791 	md_bitmap_wait_behind_writes(mddev);
1792 
1793 	mutex_lock(&mddev->bitmap_info.mutex);
1794 	spin_lock(&mddev->lock);
1795 	mddev->bitmap = NULL; /* disconnect from the md device */
1796 	spin_unlock(&mddev->lock);
1797 	mutex_unlock(&mddev->bitmap_info.mutex);
1798 	if (mddev->thread)
1799 		mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1800 
1801 	md_bitmap_free(bitmap);
1802 }
1803 
1804 /*
1805  * initialize the bitmap structure
1806  * if this returns an error, bitmap_destroy must be called to do clean up
1807  * once mddev->bitmap is set
1808  */
1809 struct bitmap *md_bitmap_create(struct mddev *mddev, int slot)
1810 {
1811 	struct bitmap *bitmap;
1812 	sector_t blocks = mddev->resync_max_sectors;
1813 	struct file *file = mddev->bitmap_info.file;
1814 	int err;
1815 	struct kernfs_node *bm = NULL;
1816 
1817 	BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1818 
1819 	BUG_ON(file && mddev->bitmap_info.offset);
1820 
1821 	if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
1822 		pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
1823 			  mdname(mddev));
1824 		return ERR_PTR(-EBUSY);
1825 	}
1826 
1827 	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1828 	if (!bitmap)
1829 		return ERR_PTR(-ENOMEM);
1830 
1831 	spin_lock_init(&bitmap->counts.lock);
1832 	atomic_set(&bitmap->pending_writes, 0);
1833 	init_waitqueue_head(&bitmap->write_wait);
1834 	init_waitqueue_head(&bitmap->overflow_wait);
1835 	init_waitqueue_head(&bitmap->behind_wait);
1836 
1837 	bitmap->mddev = mddev;
1838 	bitmap->cluster_slot = slot;
1839 
1840 	if (mddev->kobj.sd)
1841 		bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
1842 	if (bm) {
1843 		bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
1844 		sysfs_put(bm);
1845 	} else
1846 		bitmap->sysfs_can_clear = NULL;
1847 
1848 	bitmap->storage.file = file;
1849 	if (file) {
1850 		get_file(file);
1851 		/* As future accesses to this file will use bmap,
1852 		 * and bypass the page cache, we must sync the file
1853 		 * first.
1854 		 */
1855 		vfs_fsync(file, 1);
1856 	}
1857 	/* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1858 	if (!mddev->bitmap_info.external) {
1859 		/*
1860 		 * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1861 		 * instructing us to create a new on-disk bitmap instance.
1862 		 */
1863 		if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1864 			err = md_bitmap_new_disk_sb(bitmap);
1865 		else
1866 			err = md_bitmap_read_sb(bitmap);
1867 	} else {
1868 		err = 0;
1869 		if (mddev->bitmap_info.chunksize == 0 ||
1870 		    mddev->bitmap_info.daemon_sleep == 0)
1871 			/* chunksize and time_base need to be
1872 			 * set first. */
1873 			err = -EINVAL;
1874 	}
1875 	if (err)
1876 		goto error;
1877 
1878 	bitmap->daemon_lastrun = jiffies;
1879 	err = md_bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1880 	if (err)
1881 		goto error;
1882 
1883 	pr_debug("created bitmap (%lu pages) for device %s\n",
1884 		 bitmap->counts.pages, bmname(bitmap));
1885 
1886 	err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1887 	if (err)
1888 		goto error;
1889 
1890 	return bitmap;
1891  error:
1892 	md_bitmap_free(bitmap);
1893 	return ERR_PTR(err);
1894 }
1895 
1896 int md_bitmap_load(struct mddev *mddev)
1897 {
1898 	int err = 0;
1899 	sector_t start = 0;
1900 	sector_t sector = 0;
1901 	struct bitmap *bitmap = mddev->bitmap;
1902 
1903 	if (!bitmap)
1904 		goto out;
1905 
1906 	if (mddev_is_clustered(mddev))
1907 		md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
1908 
1909 	/* Clear out old bitmap info first:  Either there is none, or we
1910 	 * are resuming after someone else has possibly changed things,
1911 	 * so we should forget old cached info.
1912 	 * All chunks should be clean, but some might need_sync.
1913 	 */
1914 	while (sector < mddev->resync_max_sectors) {
1915 		sector_t blocks;
1916 		md_bitmap_start_sync(bitmap, sector, &blocks, 0);
1917 		sector += blocks;
1918 	}
1919 	md_bitmap_close_sync(bitmap);
1920 
1921 	if (mddev->degraded == 0
1922 	    || bitmap->events_cleared == mddev->events)
1923 		/* no need to keep dirty bits to optimise a
1924 		 * re-add of a missing device */
1925 		start = mddev->recovery_cp;
1926 
1927 	mutex_lock(&mddev->bitmap_info.mutex);
1928 	err = md_bitmap_init_from_disk(bitmap, start);
1929 	mutex_unlock(&mddev->bitmap_info.mutex);
1930 
1931 	if (err)
1932 		goto out;
1933 	clear_bit(BITMAP_STALE, &bitmap->flags);
1934 
1935 	/* Kick recovery in case any bits were set */
1936 	set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1937 
1938 	mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1939 	md_wakeup_thread(mddev->thread);
1940 
1941 	md_bitmap_update_sb(bitmap);
1942 
1943 	if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1944 		err = -EIO;
1945 out:
1946 	return err;
1947 }
1948 EXPORT_SYMBOL_GPL(md_bitmap_load);
1949 
1950 struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
1951 {
1952 	int rv = 0;
1953 	struct bitmap *bitmap;
1954 
1955 	bitmap = md_bitmap_create(mddev, slot);
1956 	if (IS_ERR(bitmap)) {
1957 		rv = PTR_ERR(bitmap);
1958 		return ERR_PTR(rv);
1959 	}
1960 
1961 	rv = md_bitmap_init_from_disk(bitmap, 0);
1962 	if (rv) {
1963 		md_bitmap_free(bitmap);
1964 		return ERR_PTR(rv);
1965 	}
1966 
1967 	return bitmap;
1968 }
1969 EXPORT_SYMBOL(get_bitmap_from_slot);
1970 
1971 /* Loads the bitmap associated with slot and copies the resync information
1972  * to our bitmap
1973  */
1974 int md_bitmap_copy_from_slot(struct mddev *mddev, int slot,
1975 		sector_t *low, sector_t *high, bool clear_bits)
1976 {
1977 	int rv = 0, i, j;
1978 	sector_t block, lo = 0, hi = 0;
1979 	struct bitmap_counts *counts;
1980 	struct bitmap *bitmap;
1981 
1982 	bitmap = get_bitmap_from_slot(mddev, slot);
1983 	if (IS_ERR(bitmap)) {
1984 		pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
1985 		return -1;
1986 	}
1987 
1988 	counts = &bitmap->counts;
1989 	for (j = 0; j < counts->chunks; j++) {
1990 		block = (sector_t)j << counts->chunkshift;
1991 		if (md_bitmap_file_test_bit(bitmap, block)) {
1992 			if (!lo)
1993 				lo = block;
1994 			hi = block;
1995 			md_bitmap_file_clear_bit(bitmap, block);
1996 			md_bitmap_set_memory_bits(mddev->bitmap, block, 1);
1997 			md_bitmap_file_set_bit(mddev->bitmap, block);
1998 		}
1999 	}
2000 
2001 	if (clear_bits) {
2002 		md_bitmap_update_sb(bitmap);
2003 		/* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
2004 		 * BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
2005 		for (i = 0; i < bitmap->storage.file_pages; i++)
2006 			if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
2007 				set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
2008 		md_bitmap_unplug(bitmap);
2009 	}
2010 	md_bitmap_unplug(mddev->bitmap);
2011 	*low = lo;
2012 	*high = hi;
2013 
2014 	return rv;
2015 }
2016 EXPORT_SYMBOL_GPL(md_bitmap_copy_from_slot);
2017 
2018 
2019 void md_bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
2020 {
2021 	unsigned long chunk_kb;
2022 	struct bitmap_counts *counts;
2023 
2024 	if (!bitmap)
2025 		return;
2026 
2027 	counts = &bitmap->counts;
2028 
2029 	chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
2030 	seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
2031 		   "%lu%s chunk",
2032 		   counts->pages - counts->missing_pages,
2033 		   counts->pages,
2034 		   (counts->pages - counts->missing_pages)
2035 		   << (PAGE_SHIFT - 10),
2036 		   chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
2037 		   chunk_kb ? "KB" : "B");
2038 	if (bitmap->storage.file) {
2039 		seq_printf(seq, ", file: ");
2040 		seq_file_path(seq, bitmap->storage.file, " \t\n");
2041 	}
2042 
2043 	seq_printf(seq, "\n");
2044 }
2045 
2046 int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2047 		  int chunksize, int init)
2048 {
2049 	/* If chunk_size is 0, choose an appropriate chunk size.
2050 	 * Then possibly allocate new storage space.
2051 	 * Then quiesce, copy bits, replace bitmap, and re-start
2052 	 *
2053 	 * This function is called both to set up the initial bitmap
2054 	 * and to resize the bitmap while the array is active.
2055 	 * If this happens as a result of the array being resized,
2056 	 * chunksize will be zero, and we need to choose a suitable
2057 	 * chunksize, otherwise we use what we are given.
2058 	 */
2059 	struct bitmap_storage store;
2060 	struct bitmap_counts old_counts;
2061 	unsigned long chunks;
2062 	sector_t block;
2063 	sector_t old_blocks, new_blocks;
2064 	int chunkshift;
2065 	int ret = 0;
2066 	long pages;
2067 	struct bitmap_page *new_bp;
2068 
2069 	if (bitmap->storage.file && !init) {
2070 		pr_info("md: cannot resize file-based bitmap\n");
2071 		return -EINVAL;
2072 	}
2073 
2074 	if (chunksize == 0) {
2075 		/* If there is enough space, leave the chunk size unchanged,
2076 		 * else increase by factor of two until there is enough space.
2077 		 */
2078 		long bytes;
2079 		long space = bitmap->mddev->bitmap_info.space;
2080 
2081 		if (space == 0) {
2082 			/* We don't know how much space there is, so limit
2083 			 * to current size - in sectors.
2084 			 */
2085 			bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2086 			if (!bitmap->mddev->bitmap_info.external)
2087 				bytes += sizeof(bitmap_super_t);
2088 			space = DIV_ROUND_UP(bytes, 512);
2089 			bitmap->mddev->bitmap_info.space = space;
2090 		}
2091 		chunkshift = bitmap->counts.chunkshift;
2092 		chunkshift--;
2093 		do {
2094 			/* 'chunkshift' is shift from block size to chunk size */
2095 			chunkshift++;
2096 			chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2097 			bytes = DIV_ROUND_UP(chunks, 8);
2098 			if (!bitmap->mddev->bitmap_info.external)
2099 				bytes += sizeof(bitmap_super_t);
2100 		} while (bytes > (space << 9));
2101 	} else
2102 		chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2103 
2104 	chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2105 	memset(&store, 0, sizeof(store));
2106 	if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2107 		ret = md_bitmap_storage_alloc(&store, chunks,
2108 					      !bitmap->mddev->bitmap_info.external,
2109 					      mddev_is_clustered(bitmap->mddev)
2110 					      ? bitmap->cluster_slot : 0);
2111 	if (ret) {
2112 		md_bitmap_file_unmap(&store);
2113 		goto err;
2114 	}
2115 
2116 	pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2117 
2118 	new_bp = kcalloc(pages, sizeof(*new_bp), GFP_KERNEL);
2119 	ret = -ENOMEM;
2120 	if (!new_bp) {
2121 		md_bitmap_file_unmap(&store);
2122 		goto err;
2123 	}
2124 
2125 	if (!init)
2126 		bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2127 
2128 	store.file = bitmap->storage.file;
2129 	bitmap->storage.file = NULL;
2130 
2131 	if (store.sb_page && bitmap->storage.sb_page)
2132 		memcpy(page_address(store.sb_page),
2133 		       page_address(bitmap->storage.sb_page),
2134 		       sizeof(bitmap_super_t));
2135 	md_bitmap_file_unmap(&bitmap->storage);
2136 	bitmap->storage = store;
2137 
2138 	old_counts = bitmap->counts;
2139 	bitmap->counts.bp = new_bp;
2140 	bitmap->counts.pages = pages;
2141 	bitmap->counts.missing_pages = pages;
2142 	bitmap->counts.chunkshift = chunkshift;
2143 	bitmap->counts.chunks = chunks;
2144 	bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
2145 						     BITMAP_BLOCK_SHIFT);
2146 
2147 	blocks = min(old_counts.chunks << old_counts.chunkshift,
2148 		     chunks << chunkshift);
2149 
2150 	spin_lock_irq(&bitmap->counts.lock);
2151 	/* For cluster raid, need to pre-allocate bitmap */
2152 	if (mddev_is_clustered(bitmap->mddev)) {
2153 		unsigned long page;
2154 		for (page = 0; page < pages; page++) {
2155 			ret = md_bitmap_checkpage(&bitmap->counts, page, 1, 1);
2156 			if (ret) {
2157 				unsigned long k;
2158 
2159 				/* deallocate the page memory */
2160 				for (k = 0; k < page; k++) {
2161 					kfree(new_bp[k].map);
2162 				}
2163 				kfree(new_bp);
2164 
2165 				/* restore some fields from old_counts */
2166 				bitmap->counts.bp = old_counts.bp;
2167 				bitmap->counts.pages = old_counts.pages;
2168 				bitmap->counts.missing_pages = old_counts.pages;
2169 				bitmap->counts.chunkshift = old_counts.chunkshift;
2170 				bitmap->counts.chunks = old_counts.chunks;
2171 				bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
2172 									     BITMAP_BLOCK_SHIFT);
2173 				blocks = old_counts.chunks << old_counts.chunkshift;
2174 				pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2175 				break;
2176 			} else
2177 				bitmap->counts.bp[page].count += 1;
2178 		}
2179 	}
2180 
2181 	for (block = 0; block < blocks; ) {
2182 		bitmap_counter_t *bmc_old, *bmc_new;
2183 		int set;
2184 
2185 		bmc_old = md_bitmap_get_counter(&old_counts, block, &old_blocks, 0);
2186 		set = bmc_old && NEEDED(*bmc_old);
2187 
2188 		if (set) {
2189 			bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2190 			if (*bmc_new == 0) {
2191 				/* need to set on-disk bits too. */
2192 				sector_t end = block + new_blocks;
2193 				sector_t start = block >> chunkshift;
2194 				start <<= chunkshift;
2195 				while (start < end) {
2196 					md_bitmap_file_set_bit(bitmap, block);
2197 					start += 1 << chunkshift;
2198 				}
2199 				*bmc_new = 2;
2200 				md_bitmap_count_page(&bitmap->counts, block, 1);
2201 				md_bitmap_set_pending(&bitmap->counts, block);
2202 			}
2203 			*bmc_new |= NEEDED_MASK;
2204 			if (new_blocks < old_blocks)
2205 				old_blocks = new_blocks;
2206 		}
2207 		block += old_blocks;
2208 	}
2209 
2210 	if (bitmap->counts.bp != old_counts.bp) {
2211 		unsigned long k;
2212 		for (k = 0; k < old_counts.pages; k++)
2213 			if (!old_counts.bp[k].hijacked)
2214 				kfree(old_counts.bp[k].map);
2215 		kfree(old_counts.bp);
2216 	}
2217 
2218 	if (!init) {
2219 		int i;
2220 		while (block < (chunks << chunkshift)) {
2221 			bitmap_counter_t *bmc;
2222 			bmc = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
2223 			if (bmc) {
2224 				/* new space.  It needs to be resynced, so
2225 				 * we set NEEDED_MASK.
2226 				 */
2227 				if (*bmc == 0) {
2228 					*bmc = NEEDED_MASK | 2;
2229 					md_bitmap_count_page(&bitmap->counts, block, 1);
2230 					md_bitmap_set_pending(&bitmap->counts, 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 		md_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(md_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_suspend(mddev);
2292 			md_bitmap_destroy(mddev);
2293 			mddev_resume(mddev);
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 				bitmap = md_bitmap_create(mddev, -1);
2331 				mddev_suspend(mddev);
2332 				if (IS_ERR(bitmap))
2333 					rv = PTR_ERR(bitmap);
2334 				else {
2335 					mddev->bitmap = bitmap;
2336 					rv = md_bitmap_load(mddev);
2337 					if (rv)
2338 						mddev->bitmap_info.offset = 0;
2339 				}
2340 				if (rv) {
2341 					md_bitmap_destroy(mddev);
2342 					mddev_resume(mddev);
2343 					goto out;
2344 				}
2345 				mddev_resume(mddev);
2346 			}
2347 		}
2348 	}
2349 	if (!mddev->external) {
2350 		/* Ensure new bitmap info is stored in
2351 		 * metadata promptly.
2352 		 */
2353 		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2354 		md_wakeup_thread(mddev->thread);
2355 	}
2356 	rv = 0;
2357 out:
2358 	mddev_unlock(mddev);
2359 	if (rv)
2360 		return rv;
2361 	return len;
2362 }
2363 
2364 static struct md_sysfs_entry bitmap_location =
2365 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2366 
2367 /* 'bitmap/space' is the space available at 'location' for the
2368  * bitmap.  This allows the kernel to know when it is safe to
2369  * resize the bitmap to match a resized array.
2370  */
2371 static ssize_t
2372 space_show(struct mddev *mddev, char *page)
2373 {
2374 	return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2375 }
2376 
2377 static ssize_t
2378 space_store(struct mddev *mddev, const char *buf, size_t len)
2379 {
2380 	unsigned long sectors;
2381 	int rv;
2382 
2383 	rv = kstrtoul(buf, 10, &sectors);
2384 	if (rv)
2385 		return rv;
2386 
2387 	if (sectors == 0)
2388 		return -EINVAL;
2389 
2390 	if (mddev->bitmap &&
2391 	    sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2392 		return -EFBIG; /* Bitmap is too big for this small space */
2393 
2394 	/* could make sure it isn't too big, but that isn't really
2395 	 * needed - user-space should be careful.
2396 	 */
2397 	mddev->bitmap_info.space = sectors;
2398 	return len;
2399 }
2400 
2401 static struct md_sysfs_entry bitmap_space =
2402 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2403 
2404 static ssize_t
2405 timeout_show(struct mddev *mddev, char *page)
2406 {
2407 	ssize_t len;
2408 	unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2409 	unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2410 
2411 	len = sprintf(page, "%lu", secs);
2412 	if (jifs)
2413 		len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2414 	len += sprintf(page+len, "\n");
2415 	return len;
2416 }
2417 
2418 static ssize_t
2419 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2420 {
2421 	/* timeout can be set at any time */
2422 	unsigned long timeout;
2423 	int rv = strict_strtoul_scaled(buf, &timeout, 4);
2424 	if (rv)
2425 		return rv;
2426 
2427 	/* just to make sure we don't overflow... */
2428 	if (timeout >= LONG_MAX / HZ)
2429 		return -EINVAL;
2430 
2431 	timeout = timeout * HZ / 10000;
2432 
2433 	if (timeout >= MAX_SCHEDULE_TIMEOUT)
2434 		timeout = MAX_SCHEDULE_TIMEOUT-1;
2435 	if (timeout < 1)
2436 		timeout = 1;
2437 	mddev->bitmap_info.daemon_sleep = timeout;
2438 	if (mddev->thread) {
2439 		/* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2440 		 * the bitmap is all clean and we don't need to
2441 		 * adjust the timeout right now
2442 		 */
2443 		if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2444 			mddev->thread->timeout = timeout;
2445 			md_wakeup_thread(mddev->thread);
2446 		}
2447 	}
2448 	return len;
2449 }
2450 
2451 static struct md_sysfs_entry bitmap_timeout =
2452 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2453 
2454 static ssize_t
2455 backlog_show(struct mddev *mddev, char *page)
2456 {
2457 	return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2458 }
2459 
2460 static ssize_t
2461 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2462 {
2463 	unsigned long backlog;
2464 	int rv = kstrtoul(buf, 10, &backlog);
2465 	if (rv)
2466 		return rv;
2467 	if (backlog > COUNTER_MAX)
2468 		return -EINVAL;
2469 	mddev->bitmap_info.max_write_behind = backlog;
2470 	return len;
2471 }
2472 
2473 static struct md_sysfs_entry bitmap_backlog =
2474 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2475 
2476 static ssize_t
2477 chunksize_show(struct mddev *mddev, char *page)
2478 {
2479 	return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2480 }
2481 
2482 static ssize_t
2483 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2484 {
2485 	/* Can only be changed when no bitmap is active */
2486 	int rv;
2487 	unsigned long csize;
2488 	if (mddev->bitmap)
2489 		return -EBUSY;
2490 	rv = kstrtoul(buf, 10, &csize);
2491 	if (rv)
2492 		return rv;
2493 	if (csize < 512 ||
2494 	    !is_power_of_2(csize))
2495 		return -EINVAL;
2496 	mddev->bitmap_info.chunksize = csize;
2497 	return len;
2498 }
2499 
2500 static struct md_sysfs_entry bitmap_chunksize =
2501 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2502 
2503 static ssize_t metadata_show(struct mddev *mddev, char *page)
2504 {
2505 	if (mddev_is_clustered(mddev))
2506 		return sprintf(page, "clustered\n");
2507 	return sprintf(page, "%s\n", (mddev->bitmap_info.external
2508 				      ? "external" : "internal"));
2509 }
2510 
2511 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2512 {
2513 	if (mddev->bitmap ||
2514 	    mddev->bitmap_info.file ||
2515 	    mddev->bitmap_info.offset)
2516 		return -EBUSY;
2517 	if (strncmp(buf, "external", 8) == 0)
2518 		mddev->bitmap_info.external = 1;
2519 	else if ((strncmp(buf, "internal", 8) == 0) ||
2520 			(strncmp(buf, "clustered", 9) == 0))
2521 		mddev->bitmap_info.external = 0;
2522 	else
2523 		return -EINVAL;
2524 	return len;
2525 }
2526 
2527 static struct md_sysfs_entry bitmap_metadata =
2528 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2529 
2530 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2531 {
2532 	int len;
2533 	spin_lock(&mddev->lock);
2534 	if (mddev->bitmap)
2535 		len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2536 					     "false" : "true"));
2537 	else
2538 		len = sprintf(page, "\n");
2539 	spin_unlock(&mddev->lock);
2540 	return len;
2541 }
2542 
2543 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2544 {
2545 	if (mddev->bitmap == NULL)
2546 		return -ENOENT;
2547 	if (strncmp(buf, "false", 5) == 0)
2548 		mddev->bitmap->need_sync = 1;
2549 	else if (strncmp(buf, "true", 4) == 0) {
2550 		if (mddev->degraded)
2551 			return -EBUSY;
2552 		mddev->bitmap->need_sync = 0;
2553 	} else
2554 		return -EINVAL;
2555 	return len;
2556 }
2557 
2558 static struct md_sysfs_entry bitmap_can_clear =
2559 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2560 
2561 static ssize_t
2562 behind_writes_used_show(struct mddev *mddev, char *page)
2563 {
2564 	ssize_t ret;
2565 	spin_lock(&mddev->lock);
2566 	if (mddev->bitmap == NULL)
2567 		ret = sprintf(page, "0\n");
2568 	else
2569 		ret = sprintf(page, "%lu\n",
2570 			      mddev->bitmap->behind_writes_used);
2571 	spin_unlock(&mddev->lock);
2572 	return ret;
2573 }
2574 
2575 static ssize_t
2576 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2577 {
2578 	if (mddev->bitmap)
2579 		mddev->bitmap->behind_writes_used = 0;
2580 	return len;
2581 }
2582 
2583 static struct md_sysfs_entry max_backlog_used =
2584 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2585        behind_writes_used_show, behind_writes_used_reset);
2586 
2587 static struct attribute *md_bitmap_attrs[] = {
2588 	&bitmap_location.attr,
2589 	&bitmap_space.attr,
2590 	&bitmap_timeout.attr,
2591 	&bitmap_backlog.attr,
2592 	&bitmap_chunksize.attr,
2593 	&bitmap_metadata.attr,
2594 	&bitmap_can_clear.attr,
2595 	&max_backlog_used.attr,
2596 	NULL
2597 };
2598 struct attribute_group md_bitmap_group = {
2599 	.name = "bitmap",
2600 	.attrs = md_bitmap_attrs,
2601 };
2602 
2603