1	// SPDX-License-Identifier: GPL-2.0-only
2	/*
3	* bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
4	*
5	* bitmap_create - sets up the bitmap structure
6	* bitmap_destroy - destroys the bitmap structure
7	*
8	* additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
9	* - added disk storage for bitmap
10	* - changes to allow various bitmap chunk sizes
11	*/
12
13	/*
14	* Still to do:
15	*
16	* flush after percent set rather than just time based. (maybe both).
17	*/
18
19	#include <linux/blkdev.h>
20	#include <linux/module.h>
21	#include <linux/errno.h>
22	#include <linux/slab.h>
23	#include <linux/init.h>
24	#include <linux/timer.h>
25	#include <linux/sched.h>
26	#include <linux/list.h>
27	#include <linux/file.h>
28	#include <linux/mount.h>
29	#include <linux/buffer_head.h>
30	#include <linux/seq_file.h>
31	#include <trace/events/block.h>
32
33	#include "md.h"
34	#include "md-bitmap.h"
35	#include "md-cluster.h"
36
37	/*
38	* in-memory bitmap:
39	*
40	* Use 16 bit block counters to track pending writes to each "chunk".
41	* The 2 high order bits are special-purpose, the first is a flag indicating
42	* whether a resync is needed. The second is a flag indicating whether a
43	* resync is active.
44	* This means that the counter is actually 14 bits:
45	*
46	* +--------+--------+------------------------------------------------+
47	* | resync | resync | counter |
48	* | needed | active | |
49	* | (0-1) | (0-1) | (0-16383) |
50	* +--------+--------+------------------------------------------------+
51	*
52	* The "resync needed" bit is set when:
53	* a '1' bit is read from storage at startup.
54	* a write request fails on some drives
55	* a resync is aborted on a chunk with 'resync active' set
56	* It is cleared (and resync-active set) when a resync starts across all drives
57	* of the chunk.
58	*
59	*
60	* The "resync active" bit is set when:
61	* a resync is started on all drives, and resync_needed is set.
62	* resync_needed will be cleared (as long as resync_active wasn't already set).
63	* It is cleared when a resync completes.
64	*
65	* The counter counts pending write requests, plus the on-disk bit.
66	* When the counter is '1' and the resync bits are clear, the on-disk
67	* bit can be cleared as well, thus setting the counter to 0.
68	* When we set a bit, or in the counter (to start a write), if the fields is
69	* 0, we first set the disk bit and set the counter to 1.
70	*
71	* If the counter is 0, the on-disk bit is clear and the stripe is clean
72	* Anything that dirties the stripe pushes the counter to 2 (at least)
73	* and sets the on-disk bit (lazily).
74	* If a periodic sweep find the counter at 2, it is decremented to 1.
75	* If the sweep find the counter at 1, the on-disk bit is cleared and the
76	* counter goes to zero.
77	*
78	* Also, we'll hijack the "map" pointer itself and use it as two 16 bit block
79	* counters as a fallback when "page" memory cannot be allocated:
80	*
81	* Normal case (page memory allocated):
82	*
83	* page pointer (32-bit)
84	*
85	* [ ] ------+
86	* |
87	* +-------> [ ][ ]..[ ] (4096 byte page == 2048 counters)
88	* c1 c2 c2048
89	*
90	* Hijacked case (page memory allocation failed):
91	*
92	* hijacked page pointer (32-bit)
93	*
94	* [ ][ ] (no page memory allocated)
95	* counter #1 (16-bit) counter #2 (16-bit)
96	*
97	*/
98
99	typedef __u16 bitmap_counter_t;
100
101	#define PAGE_BITS (PAGE_SIZE << 3)
102	#define PAGE_BIT_SHIFT (PAGE_SHIFT + 3)
103
104	#define COUNTER_BITS 16
105	#define COUNTER_BIT_SHIFT 4
106	#define COUNTER_BYTE_SHIFT (COUNTER_BIT_SHIFT - 3)
107
108	#define NEEDED_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 1)))
109	#define RESYNC_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 2)))
110	#define COUNTER_MAX ((bitmap_counter_t) RESYNC_MASK - 1)
111
112	#define NEEDED(x) (((bitmap_counter_t) x) & NEEDED_MASK)
113	#define RESYNC(x) (((bitmap_counter_t) x) & RESYNC_MASK)
114	#define COUNTER(x) (((bitmap_counter_t) x) & COUNTER_MAX)
115
116	/* how many counters per page? */
117	#define PAGE_COUNTER_RATIO (PAGE_BITS / COUNTER_BITS)
118	/* same, except a shift value for more efficient bitops */
119	#define PAGE_COUNTER_SHIFT (PAGE_BIT_SHIFT - COUNTER_BIT_SHIFT)
120	/* same, except a mask value for more efficient bitops */
121	#define PAGE_COUNTER_MASK (PAGE_COUNTER_RATIO - 1)
122
123	#define BITMAP_BLOCK_SHIFT 9
124
125	/*
126	* bitmap structures:
127	*/
128
129	/* the in-memory bitmap is represented by bitmap_pages */
130	struct bitmap_page {
131	/*
132	* map points to the actual memory page
133	*/
134	char *map;
135	/*
136	* in emergencies (when map cannot be alloced), hijack the map
137	* pointer and use it as two counters itself
138	*/
139	unsigned int hijacked:1;
140	/*
141	* If any counter in this page is '1' or '2' - and so could be
142	* cleared then that page is marked as 'pending'
143	*/
144	unsigned int pending:1;
145	/*
146	* count of dirty bits on the page
147	*/
148	unsigned int count:30;
149	};
150
151	/* the main bitmap structure - one per mddev */
152	struct bitmap {
153
154	struct bitmap_counts {
155	spinlock_t lock;
156	struct bitmap_page *bp;
157	/* total number of pages in the bitmap */
158	unsigned long pages;
159	/* number of pages not yet allocated */
160	unsigned long missing_pages;
161	/* chunksize = 2^chunkshift (for bitops) */
162	unsigned long chunkshift;
163	/* total number of data chunks for the array */
164	unsigned long chunks;
165	} counts;
166
167	struct mddev *mddev; /* the md device that the bitmap is for */
168
169	__u64 events_cleared;
170	int need_sync;
171
172	struct bitmap_storage {
173	/* backing disk file */
174	struct file *file;
175	/* cached copy of the bitmap file superblock */
176	struct page *sb_page;
177	unsigned long sb_index;
178	/* list of cache pages for the file */
179	struct page **filemap;
180	/* attributes associated filemap pages */
181	unsigned long *filemap_attr;
182	/* number of pages in the file */
183	unsigned long file_pages;
184	/* total bytes in the bitmap */
185	unsigned long bytes;
186	} storage;
187
188	unsigned long flags;
189
190	int allclean;
191
192	atomic_t behind_writes;
193	/* highest actual value at runtime */
194	unsigned long behind_writes_used;
195
196	/*
197	* the bitmap daemon - periodically wakes up and sweeps the bitmap
198	* file, cleaning up bits and flushing out pages to disk as necessary
199	*/
200	unsigned long daemon_lastrun; /* jiffies of last run */
201	/*
202	* when we lasted called end_sync to update bitmap with resync
203	* progress.
204	*/
205	unsigned long last_end_sync;
206
207	/* pending writes to the bitmap file */
208	atomic_t pending_writes;
209	wait_queue_head_t write_wait;
210	wait_queue_head_t overflow_wait;
211	wait_queue_head_t behind_wait;
212
213	struct kernfs_node *sysfs_can_clear;
214	/* slot offset for clustered env */
215	int cluster_slot;
216	};
217
218	static struct workqueue_struct *md_bitmap_wq;
219
220	static int __bitmap_resize(struct bitmap *bitmap, sector_t blocks,
221	int chunksize, bool init);
222
223	static inline char *bmname(struct bitmap *bitmap)
224	{
225	return bitmap->mddev ? mdname(mddev: bitmap->mddev) : "mdX";
226	}
227
228	static bool bitmap_enabled(void *data, bool flush)
229	{
230	struct bitmap *bitmap = data;
231
232	if (!flush)
233	return true;
234
235	/*
236	* If caller want to flush bitmap pages to underlying disks, check if
237	* there are cached pages in filemap.
238	*/
239	return !test_bit(BITMAP_STALE, &bitmap->flags) &&
240	bitmap->storage.filemap != NULL;
241	}
242
243	/*
244	* check a page and, if necessary, allocate it (or hijack it if the alloc fails)
245	*
246	* 1) check to see if this page is allocated, if it's not then try to alloc
247	* 2) if the alloc fails, set the page's hijacked flag so we'll use the
248	* page pointer directly as a counter
249	*
250	* if we find our page, we increment the page's refcount so that it stays
251	* allocated while we're using it
252	*/
253	static int md_bitmap_checkpage(struct bitmap_counts *bitmap,
254	unsigned long page, int create, int no_hijack)
255	__releases(bitmap->lock)
256	__acquires(bitmap->lock)
257	{
258	unsigned char *mappage;
259
260	WARN_ON_ONCE(page >= bitmap->pages);
261	if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
262	return 0;
263
264	if (bitmap->bp[page].map) /* page is already allocated, just return */
265	return 0;
266
267	if (!create)
268	return -ENOENT;
269
270	/* this page has not been allocated yet */
271
272	spin_unlock_irq(lock: &bitmap->lock);
273	/* It is possible that this is being called inside a
274	* prepare_to_wait/finish_wait loop from raid5c:make_request().
275	* In general it is not permitted to sleep in that context as it
276	* can cause the loop to spin freely.
277	* That doesn't apply here as we can only reach this point
278	* once with any loop.
279	* When this function completes, either bp[page].map or
280	* bp[page].hijacked. In either case, this function will
281	* abort before getting to this point again. So there is
282	* no risk of a free-spin, and so it is safe to assert
283	* that sleeping here is allowed.
284	*/
285	sched_annotate_sleep();
286	mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
287	spin_lock_irq(lock: &bitmap->lock);
288
289	if (mappage == NULL) {
290	pr_debug("md/bitmap: map page allocation failed, hijacking\n");
291	/* We don't support hijack for cluster raid */
292	if (no_hijack)
293	return -ENOMEM;
294	/* failed - set the hijacked flag so that we can use the
295	* pointer as a counter */
296	if (!bitmap->bp[page].map)
297	bitmap->bp[page].hijacked = 1;
298	} else if (bitmap->bp[page].map ||
299	bitmap->bp[page].hijacked) {
300	/* somebody beat us to getting the page */
301	kfree(objp: mappage);
302	} else {
303
304	/* no page was in place and we have one, so install it */
305
306	bitmap->bp[page].map = mappage;
307	bitmap->missing_pages--;
308	}
309	return 0;
310	}
311
312	/* if page is completely empty, put it back on the free list, or dealloc it */
313	/* if page was hijacked, unmark the flag so it might get alloced next time */
314	/* Note: lock should be held when calling this */
315	static void md_bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
316	{
317	char *ptr;
318
319	if (bitmap->bp[page].count) /* page is still busy */
320	return;
321
322	/* page is no longer in use, it can be released */
323
324	if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
325	bitmap->bp[page].hijacked = 0;
326	bitmap->bp[page].map = NULL;
327	} else {
328	/* normal case, free the page */
329	ptr = bitmap->bp[page].map;
330	bitmap->bp[page].map = NULL;
331	bitmap->missing_pages++;
332	kfree(objp: ptr);
333	}
334	}
335
336	/*
337	* bitmap file handling - read and write the bitmap file and its superblock
338	*/
339
340	/*
341	* basic page I/O operations
342	*/
343
344	/* IO operations when bitmap is stored near all superblocks */
345
346	/* choose a good rdev and read the page from there */
347	static int read_sb_page(struct mddev *mddev, loff_t offset,
348	struct page *page, unsigned long index, int size)
349	{
350
351	sector_t sector = mddev->bitmap_info.offset + offset +
352	index * (PAGE_SIZE / SECTOR_SIZE);
353	struct md_rdev *rdev;
354
355	rdev_for_each(rdev, mddev) {
356	u32 iosize = roundup(size, bdev_logical_block_size(rdev->bdev));
357
358	if (!test_bit(In_sync, &rdev->flags) ||
359	test_bit(Faulty, &rdev->flags) ||
360	test_bit(Bitmap_sync, &rdev->flags))
361	continue;
362
363	if (sync_page_io(rdev, sector, size: iosize, page, opf: REQ_OP_READ, metadata_op: true))
364	return 0;
365	}
366	return -EIO;
367	}
368
369	static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
370	{
371	/* Iterate the disks of an mddev, using rcu to protect access to the
372	* linked list, and raising the refcount of devices we return to ensure
373	* they don't disappear while in use.
374	* As devices are only added or removed when raid_disk is < 0 and
375	* nr_pending is 0 and In_sync is clear, the entries we return will
376	* still be in the same position on the list when we re-enter
377	* list_for_each_entry_continue_rcu.
378	*
379	* Note that if entered with 'rdev == NULL' to start at the
380	* beginning, we temporarily assign 'rdev' to an address which
381	* isn't really an rdev, but which can be used by
382	* list_for_each_entry_continue_rcu() to find the first entry.
383	*/
384	rcu_read_lock();
385	if (rdev == NULL)
386	/* start at the beginning */
387	rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
388	else {
389	/* release the previous rdev and start from there. */
390	rdev_dec_pending(rdev, mddev);
391	}
392	list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
393	if (rdev->raid_disk >= 0 &&
394	!test_bit(Faulty, &rdev->flags)) {
395	/* this is a usable devices */
396	atomic_inc(v: &rdev->nr_pending);
397	rcu_read_unlock();
398	return rdev;
399	}
400	}
401	rcu_read_unlock();
402	return NULL;
403	}
404
405	static unsigned int optimal_io_size(struct block_device *bdev,
406	unsigned int last_page_size,
407	unsigned int io_size)
408	{
409	if (bdev_io_opt(bdev) > bdev_logical_block_size(bdev))
410	return roundup(last_page_size, bdev_io_opt(bdev));
411	return io_size;
412	}
413
414	static unsigned int bitmap_io_size(unsigned int io_size, unsigned int opt_size,
415	loff_t start, loff_t boundary)
416	{
417	if (io_size != opt_size &&
418	start + opt_size / SECTOR_SIZE <= boundary)
419	return opt_size;
420	if (start + io_size / SECTOR_SIZE <= boundary)
421	return io_size;
422
423	/* Overflows boundary */
424	return 0;
425	}
426
427	static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
428	unsigned long pg_index, struct page *page)
429	{
430	struct block_device *bdev;
431	struct mddev *mddev = bitmap->mddev;
432	struct bitmap_storage *store = &bitmap->storage;
433	unsigned long num_pages = bitmap->storage.file_pages;
434	unsigned int bitmap_limit = (num_pages - pg_index % num_pages) << PAGE_SHIFT;
435	loff_t sboff, offset = mddev->bitmap_info.offset;
436	sector_t ps = pg_index * PAGE_SIZE / SECTOR_SIZE;
437	unsigned int size = PAGE_SIZE;
438	unsigned int opt_size = PAGE_SIZE;
439	sector_t doff;
440
441	bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
442	/* we compare length (page numbers), not page offset. */
443	if ((pg_index - store->sb_index) == num_pages - 1) {
444	unsigned int last_page_size = store->bytes & (PAGE_SIZE - 1);
445
446	if (last_page_size == 0)
447	last_page_size = PAGE_SIZE;
448	size = roundup(last_page_size, bdev_logical_block_size(bdev));
449	opt_size = optimal_io_size(bdev, last_page_size, io_size: size);
450	}
451
452	sboff = rdev->sb_start + offset;
453	doff = rdev->data_offset;
454
455	/* Just make sure we aren't corrupting data or metadata */
456	if (mddev->external) {
457	/* Bitmap could be anywhere. */
458	if (sboff + ps > doff &&
459	sboff < (doff + mddev->dev_sectors + PAGE_SIZE / SECTOR_SIZE))
460	return -EINVAL;
461	} else if (offset < 0) {
462	/* DATA BITMAP METADATA */
463	size = bitmap_io_size(io_size: size, opt_size, start: offset + ps, boundary: 0);
464	if (size == 0)
465	/* bitmap runs in to metadata */
466	return -EINVAL;
467
468	if (doff + mddev->dev_sectors > sboff)
469	/* data runs in to bitmap */
470	return -EINVAL;
471	} else if (rdev->sb_start < rdev->data_offset) {
472	/* METADATA BITMAP DATA */
473	size = bitmap_io_size(io_size: size, opt_size, start: sboff + ps, boundary: doff);
474	if (size == 0)
475	/* bitmap runs in to data */
476	return -EINVAL;
477	}
478
479	md_write_metadata(mddev, rdev, sector: sboff + ps, size: (int)min(size, bitmap_limit),
480	page, offset: 0);
481	return 0;
482	}
483
484	static void write_sb_page(struct bitmap *bitmap, unsigned long pg_index,
485	struct page *page, bool wait)
486	{
487	struct mddev *mddev = bitmap->mddev;
488
489	do {
490	struct md_rdev *rdev = NULL;
491
492	while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
493	if (__write_sb_page(rdev, bitmap, pg_index, page) < 0) {
494	set_bit(nr: BITMAP_WRITE_ERROR, addr: &bitmap->flags);
495	return;
496	}
497	}
498	} while (wait && md_super_wait(mddev) < 0);
499	}
500
501	static void md_bitmap_file_kick(struct bitmap *bitmap);
502
503	#ifdef CONFIG_MD_BITMAP_FILE
504	static void write_file_page(struct bitmap *bitmap, struct page *page, int wait)
505	{
506	struct buffer_head *bh = page_buffers(page);
507
508	while (bh && bh->b_blocknr) {
509	atomic_inc(v: &bitmap->pending_writes);
510	set_buffer_locked(bh);
511	set_buffer_mapped(bh);
512	submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
513	bh = bh->b_this_page;
514	}
515
516	if (wait)
517	wait_event(bitmap->write_wait,
518	atomic_read(&bitmap->pending_writes) == 0);
519	}
520
521	static void end_bitmap_write(struct buffer_head *bh, int uptodate)
522	{
523	struct bitmap *bitmap = bh->b_private;
524
525	if (!uptodate)
526	set_bit(nr: BITMAP_WRITE_ERROR, addr: &bitmap->flags);
527	if (atomic_dec_and_test(v: &bitmap->pending_writes))
528	wake_up(&bitmap->write_wait);
529	}
530
531	static void free_buffers(struct page *page)
532	{
533	struct buffer_head *bh;
534
535	if (!PagePrivate(page))
536	return;
537
538	bh = page_buffers(page);
539	while (bh) {
540	struct buffer_head *next = bh->b_this_page;
541	free_buffer_head(bh);
542	bh = next;
543	}
544	detach_page_private(page);
545	put_page(page);
546	}
547
548	/* read a page from a file.
549	* We both read the page, and attach buffers to the page to record the
550	* address of each block (using bmap). These addresses will be used
551	* to write the block later, completely bypassing the filesystem.
552	* This usage is similar to how swap files are handled, and allows us
553	* to write to a file with no concerns of memory allocation failing.
554	*/
555	static int read_file_page(struct file *file, unsigned long index,
556	struct bitmap *bitmap, unsigned long count, struct page *page)
557	{
558	int ret = 0;
559	struct inode *inode = file_inode(f: file);
560	struct buffer_head *bh;
561	sector_t block, blk_cur;
562	unsigned long blocksize = i_blocksize(node: inode);
563
564	pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
565	(unsigned long long)index << PAGE_SHIFT);
566
567	bh = alloc_page_buffers(page, size: blocksize);
568	if (!bh) {
569	ret = -ENOMEM;
570	goto out;
571	}
572	attach_page_private(page, data: bh);
573	blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
574	while (bh) {
575	block = blk_cur;
576
577	if (count == 0)
578	bh->b_blocknr = 0;
579	else {
580	ret = bmap(inode, block: &block);
581	if (ret || !block) {
582	ret = -EINVAL;
583	bh->b_blocknr = 0;
584	goto out;
585	}
586
587	bh->b_blocknr = block;
588	bh->b_bdev = inode->i_sb->s_bdev;
589	if (count < blocksize)
590	count = 0;
591	else
592	count -= blocksize;
593
594	bh->b_end_io = end_bitmap_write;
595	bh->b_private = bitmap;
596	atomic_inc(v: &bitmap->pending_writes);
597	set_buffer_locked(bh);
598	set_buffer_mapped(bh);
599	submit_bh(REQ_OP_READ, bh);
600	}
601	blk_cur++;
602	bh = bh->b_this_page;
603	}
604
605	wait_event(bitmap->write_wait,
606	atomic_read(&bitmap->pending_writes)==0);
607	if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
608	ret = -EIO;
609	out:
610	if (ret)
611	pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
612	(int)PAGE_SIZE,
613	(unsigned long long)index << PAGE_SHIFT,
614	ret);
615	return ret;
616	}
617	#else /* CONFIG_MD_BITMAP_FILE */
618	static void write_file_page(struct bitmap *bitmap, struct page *page, int wait)
619	{
620	}
621	static int read_file_page(struct file *file, unsigned long index,
622	struct bitmap *bitmap, unsigned long count, struct page *page)
623	{
624	return -EIO;
625	}
626	static void free_buffers(struct page *page)
627	{
628	put_page(page);
629	}
630	#endif /* CONFIG_MD_BITMAP_FILE */
631
632	/*
633	* bitmap file superblock operations
634	*/
635
636	/*
637	* write out a page to a file
638	*/
639	static void filemap_write_page(struct bitmap *bitmap, unsigned long pg_index,
640	bool wait)
641	{
642	struct bitmap_storage *store = &bitmap->storage;
643	struct page *page = store->filemap[pg_index];
644
645	if (mddev_is_clustered(mddev: bitmap->mddev)) {
646	/* go to node bitmap area starting point */
647	pg_index += store->sb_index;
648	}
649
650	if (store->file)
651	write_file_page(bitmap, page, wait);
652	else
653	write_sb_page(bitmap, pg_index, page, wait);
654	}
655
656	/*
657	* md_bitmap_wait_writes() should be called before writing any bitmap
658	* blocks, to ensure previous writes, particularly from
659	* md_bitmap_daemon_work(), have completed.
660	*/
661	static void md_bitmap_wait_writes(struct bitmap *bitmap)
662	{
663	if (bitmap->storage.file)
664	wait_event(bitmap->write_wait,
665	atomic_read(&bitmap->pending_writes)==0);
666	else
667	/* Note that we ignore the return value. The writes
668	* might have failed, but that would just mean that
669	* some bits which should be cleared haven't been,
670	* which is safe. The relevant bitmap blocks will
671	* probably get written again, but there is no great
672	* loss if they aren't.
673	*/
674	md_super_wait(mddev: bitmap->mddev);
675	}
676
677
678	/* update the event counter and sync the superblock to disk */
679	static void bitmap_update_sb(void *data)
680	{
681	bitmap_super_t *sb;
682	struct bitmap *bitmap = data;
683
684	if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
685	return;
686	if (bitmap->mddev->bitmap_info.external)
687	return;
688	if (!bitmap->storage.sb_page) /* no superblock */
689	return;
690	sb = kmap_local_page(page: bitmap->storage.sb_page);
691	sb->events = cpu_to_le64(bitmap->mddev->events);
692	if (bitmap->mddev->events < bitmap->events_cleared)
693	/* rocking back to read-only */
694	bitmap->events_cleared = bitmap->mddev->events;
695	sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
696	/*
697	* clear BITMAP_WRITE_ERROR bit to protect against the case that
698	* a bitmap write error occurred but the later writes succeeded.
699	*/
700	sb->state = cpu_to_le32(bitmap->flags & ~BIT(BITMAP_WRITE_ERROR));
701	/* Just in case these have been changed via sysfs: */
702	sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
703	sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
704	/* This might have been changed by a reshape */
705	sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
706	sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
707	sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
708	sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
709	bitmap_info.space);
710	kunmap_local(sb);
711
712	if (bitmap->storage.file)
713	write_file_page(bitmap, page: bitmap->storage.sb_page, wait: 1);
714	else
715	write_sb_page(bitmap, pg_index: bitmap->storage.sb_index,
716	page: bitmap->storage.sb_page, wait: 1);
717	}
718
719	static void bitmap_print_sb(struct bitmap *bitmap)
720	{
721	bitmap_super_t *sb;
722
723	if (!bitmap || !bitmap->storage.sb_page)
724	return;
725	sb = kmap_local_page(page: bitmap->storage.sb_page);
726	pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
727	pr_debug(" magic: %08x\n", le32_to_cpu(sb->magic));
728	pr_debug(" version: %u\n", le32_to_cpu(sb->version));
729	pr_debug(" uuid: %08x.%08x.%08x.%08x\n",
730	le32_to_cpu(*(__le32 *)(sb->uuid+0)),
731	le32_to_cpu(*(__le32 *)(sb->uuid+4)),
732	le32_to_cpu(*(__le32 *)(sb->uuid+8)),
733	le32_to_cpu(*(__le32 *)(sb->uuid+12)));
734	pr_debug(" events: %llu\n",
735	(unsigned long long) le64_to_cpu(sb->events));
736	pr_debug("events cleared: %llu\n",
737	(unsigned long long) le64_to_cpu(sb->events_cleared));
738	pr_debug(" state: %08x\n", le32_to_cpu(sb->state));
739	pr_debug(" chunksize: %u B\n", le32_to_cpu(sb->chunksize));
740	pr_debug(" daemon sleep: %us\n", le32_to_cpu(sb->daemon_sleep));
741	pr_debug(" sync size: %llu KB\n",
742	(unsigned long long)le64_to_cpu(sb->sync_size)/2);
743	pr_debug("max write behind: %u\n", le32_to_cpu(sb->write_behind));
744	kunmap_local(sb);
745	}
746
747	/*
748	* bitmap_new_disk_sb
749	* @bitmap
750	*
751	* This function is somewhat the reverse of bitmap_read_sb. bitmap_read_sb
752	* reads and verifies the on-disk bitmap superblock and populates bitmap_info.
753	* This function verifies 'bitmap_info' and populates the on-disk bitmap
754	* structure, which is to be written to disk.
755	*
756	* Returns: 0 on success, -Exxx on error
757	*/
758	static int md_bitmap_new_disk_sb(struct bitmap *bitmap)
759	{
760	bitmap_super_t *sb;
761	unsigned long chunksize, daemon_sleep, write_behind;
762
763	bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
764	if (bitmap->storage.sb_page == NULL)
765	return -ENOMEM;
766	bitmap->storage.sb_index = 0;
767
768	sb = kmap_local_page(page: bitmap->storage.sb_page);
769
770	sb->magic = cpu_to_le32(BITMAP_MAGIC);
771	sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
772
773	chunksize = bitmap->mddev->bitmap_info.chunksize;
774	BUG_ON(!chunksize);
775	if (!is_power_of_2(n: chunksize)) {
776	kunmap_local(sb);
777	pr_warn("bitmap chunksize not a power of 2\n");
778	return -EINVAL;
779	}
780	sb->chunksize = cpu_to_le32(chunksize);
781
782	daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
783	if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
784	pr_debug("Choosing daemon_sleep default (5 sec)\n");
785	daemon_sleep = 5 * HZ;
786	}
787	sb->daemon_sleep = cpu_to_le32(daemon_sleep);
788	bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
789
790	/*
791	* FIXME: write_behind for RAID1. If not specified, what
792	* is a good choice? We choose COUNTER_MAX / 2 arbitrarily.
793	*/
794	write_behind = bitmap->mddev->bitmap_info.max_write_behind;
795	if (write_behind > COUNTER_MAX / 2)
796	write_behind = COUNTER_MAX / 2;
797	sb->write_behind = cpu_to_le32(write_behind);
798	bitmap->mddev->bitmap_info.max_write_behind = write_behind;
799
800	/* keep the array size field of the bitmap superblock up to date */
801	sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
802
803	memcpy(sb->uuid, bitmap->mddev->uuid, 16);
804
805	set_bit(nr: BITMAP_STALE, addr: &bitmap->flags);
806	sb->state = cpu_to_le32(bitmap->flags);
807	bitmap->events_cleared = bitmap->mddev->events;
808	sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
809	bitmap->mddev->bitmap_info.nodes = 0;
810
811	kunmap_local(sb);
812
813	return 0;
814	}
815
816	/* read the superblock from the bitmap file and initialize some bitmap fields */
817	static int md_bitmap_read_sb(struct bitmap *bitmap)
818	{
819	char *reason = NULL;
820	bitmap_super_t *sb;
821	unsigned long chunksize, daemon_sleep, write_behind;
822	unsigned long long events;
823	int nodes = 0;
824	unsigned long sectors_reserved = 0;
825	int err = -EINVAL;
826	struct page *sb_page;
827	loff_t offset = 0;
828
829	if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
830	chunksize = 128 * 1024 * 1024;
831	daemon_sleep = 5 * HZ;
832	write_behind = 0;
833	set_bit(nr: BITMAP_STALE, addr: &bitmap->flags);
834	err = 0;
835	goto out_no_sb;
836	}
837	/* page 0 is the superblock, read it... */
838	sb_page = alloc_page(GFP_KERNEL);
839	if (!sb_page)
840	return -ENOMEM;
841	bitmap->storage.sb_page = sb_page;
842
843	re_read:
844	/* If cluster_slot is set, the cluster is setup */
845	if (bitmap->cluster_slot >= 0) {
846	sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
847
848	bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks,
849	(bitmap->mddev->bitmap_info.chunksize >> 9));
850	/* bits to bytes */
851	bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
852	/* to 4k blocks */
853	bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
854	offset = bitmap->cluster_slot * (bm_blocks << 3);
855	pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
856	bitmap->cluster_slot, offset);
857	}
858
859	if (bitmap->storage.file) {
860	loff_t isize = i_size_read(inode: bitmap->storage.file->f_mapping->host);
861	int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
862
863	err = read_file_page(file: bitmap->storage.file, index: 0,
864	bitmap, count: bytes, page: sb_page);
865	} else {
866	err = read_sb_page(mddev: bitmap->mddev, offset, page: sb_page, index: 0,
867	size: sizeof(bitmap_super_t));
868	}
869	if (err)
870	return err;
871
872	err = -EINVAL;
873	sb = kmap_local_page(page: sb_page);
874
875	chunksize = le32_to_cpu(sb->chunksize);
876	daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
877	write_behind = le32_to_cpu(sb->write_behind);
878	sectors_reserved = le32_to_cpu(sb->sectors_reserved);
879
880	/* verify that the bitmap-specific fields are valid */
881	if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
882	reason = "bad magic";
883	else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
884	le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
885	reason = "unrecognized superblock version";
886	else if (chunksize < 512)
887	reason = "bitmap chunksize too small";
888	else if (!is_power_of_2(n: chunksize))
889	reason = "bitmap chunksize not a power of 2";
890	else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
891	reason = "daemon sleep period out of range";
892	else if (write_behind > COUNTER_MAX)
893	reason = "write-behind limit out of range (0 - 16383)";
894	if (reason) {
895	pr_warn("%s: invalid bitmap file superblock: %s\n",
896	bmname(bitmap), reason);
897	goto out;
898	}
899
900	/*
901	* Setup nodes/clustername only if bitmap version is
902	* cluster-compatible
903	*/
904	if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
905	nodes = le32_to_cpu(sb->nodes);
906	strscpy(bitmap->mddev->bitmap_info.cluster_name,
907	sb->cluster_name, 64);
908	}
909
910	/* keep the array size field of the bitmap superblock up to date */
911	sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
912
913	if (bitmap->mddev->persistent) {
914	/*
915	* We have a persistent array superblock, so compare the
916	* bitmap's UUID and event counter to the mddev's
917	*/
918	if (memcmp(p: sb->uuid, q: bitmap->mddev->uuid, size: 16)) {
919	pr_warn("%s: bitmap superblock UUID mismatch\n",
920	bmname(bitmap));
921	goto out;
922	}
923	events = le64_to_cpu(sb->events);
924	if (!nodes && (events < bitmap->mddev->events)) {
925	pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
926	bmname(bitmap), events,
927	(unsigned long long) bitmap->mddev->events);
928	set_bit(nr: BITMAP_STALE, addr: &bitmap->flags);
929	}
930	}
931
932	/* assign fields using values from superblock */
933	bitmap->flags |= le32_to_cpu(sb->state);
934	if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
935	set_bit(nr: BITMAP_HOSTENDIAN, addr: &bitmap->flags);
936	bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
937	err = 0;
938
939	out:
940	kunmap_local(sb);
941	if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
942	/* Assigning chunksize is required for "re_read" */
943	bitmap->mddev->bitmap_info.chunksize = chunksize;
944	err = md_setup_cluster(mddev: bitmap->mddev, nodes);
945	if (err) {
946	pr_warn("%s: Could not setup cluster service (%d)\n",
947	bmname(bitmap), err);
948	goto out_no_sb;
949	}
950	bitmap->cluster_slot = bitmap->mddev->cluster_ops->slot_number(bitmap->mddev);
951	goto re_read;
952	}
953
954	out_no_sb:
955	if (err == 0) {
956	if (test_bit(BITMAP_STALE, &bitmap->flags))
957	bitmap->events_cleared = bitmap->mddev->events;
958	bitmap->mddev->bitmap_info.chunksize = chunksize;
959	bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
960	bitmap->mddev->bitmap_info.max_write_behind = write_behind;
961	bitmap->mddev->bitmap_info.nodes = nodes;
962	if (bitmap->mddev->bitmap_info.space == 0 ||
963	bitmap->mddev->bitmap_info.space > sectors_reserved)
964	bitmap->mddev->bitmap_info.space = sectors_reserved;
965	} else {
966	bitmap_print_sb(bitmap);
967	if (bitmap->cluster_slot < 0)
968	md_cluster_stop(mddev: bitmap->mddev);
969	}
970	return err;
971	}
972
973	/*
974	* general bitmap file operations
975	*/
976
977	/*
978	* on-disk bitmap:
979	*
980	* Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
981	* file a page at a time. There's a superblock at the start of the file.
982	*/
983	/* calculate the index of the page that contains this bit */
984	static inline unsigned long file_page_index(struct bitmap_storage *store,
985	unsigned long chunk)
986	{
987	if (store->sb_page)
988	chunk += sizeof(bitmap_super_t) << 3;
989	return chunk >> PAGE_BIT_SHIFT;
990	}
991
992	/* calculate the (bit) offset of this bit within a page */
993	static inline unsigned long file_page_offset(struct bitmap_storage *store,
994	unsigned long chunk)
995	{
996	if (store->sb_page)
997	chunk += sizeof(bitmap_super_t) << 3;
998	return chunk & (PAGE_BITS - 1);
999	}
1000
1001	/*
1002	* return a pointer to the page in the filemap that contains the given bit
1003	*
1004	*/
1005	static inline struct page *filemap_get_page(struct bitmap_storage *store,
1006	unsigned long chunk)
1007	{
1008	if (file_page_index(store, chunk) >= store->file_pages)
1009	return NULL;
1010	return store->filemap[file_page_index(store, chunk)];
1011	}
1012
1013	static int md_bitmap_storage_alloc(struct bitmap_storage *store,
1014	unsigned long chunks, int with_super,
1015	int slot_number)
1016	{
1017	int pnum, offset = 0;
1018	unsigned long num_pages;
1019	unsigned long bytes;
1020
1021	bytes = DIV_ROUND_UP(chunks, 8);
1022	if (with_super)
1023	bytes += sizeof(bitmap_super_t);
1024
1025	num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
1026	offset = slot_number * num_pages;
1027
1028	store->filemap = kmalloc_array(num_pages, sizeof(struct page *),
1029	GFP_KERNEL);
1030	if (!store->filemap)
1031	return -ENOMEM;
1032
1033	if (with_super && !store->sb_page) {
1034	store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
1035	if (store->sb_page == NULL)
1036	return -ENOMEM;
1037	}
1038
1039	pnum = 0;
1040	if (store->sb_page) {
1041	store->filemap[0] = store->sb_page;
1042	pnum = 1;
1043	store->sb_index = offset;
1044	}
1045
1046	for ( ; pnum < num_pages; pnum++) {
1047	store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
1048	if (!store->filemap[pnum]) {
1049	store->file_pages = pnum;
1050	return -ENOMEM;
1051	}
1052	}
1053	store->file_pages = pnum;
1054
1055	/* We need 4 bits per page, rounded up to a multiple
1056	* of sizeof(unsigned long) */
1057	store->filemap_attr = kzalloc(
1058	roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
1059	GFP_KERNEL);
1060	if (!store->filemap_attr)
1061	return -ENOMEM;
1062
1063	store->bytes = bytes;
1064
1065	return 0;
1066	}
1067
1068	static void md_bitmap_file_unmap(struct bitmap_storage *store)
1069	{
1070	struct file *file = store->file;
1071	struct page *sb_page = store->sb_page;
1072	struct page **map = store->filemap;
1073	int pages = store->file_pages;
1074
1075	while (pages--)
1076	if (map[pages] != sb_page) /* 0 is sb_page, release it below */
1077	free_buffers(page: map[pages]);
1078	kfree(objp: map);
1079	kfree(objp: store->filemap_attr);
1080
1081	if (sb_page)
1082	free_buffers(page: sb_page);
1083
1084	if (file) {
1085	struct inode *inode = file_inode(f: file);
1086	invalidate_mapping_pages(mapping: inode->i_mapping, start: 0, end: -1);
1087	fput(file);
1088	}
1089	}
1090
1091	/*
1092	* bitmap_file_kick - if an error occurs while manipulating the bitmap file
1093	* then it is no longer reliable, so we stop using it and we mark the file
1094	* as failed in the superblock
1095	*/
1096	static void md_bitmap_file_kick(struct bitmap *bitmap)
1097	{
1098	if (!test_and_set_bit(nr: BITMAP_STALE, addr: &bitmap->flags)) {
1099	bitmap_update_sb(data: bitmap);
1100
1101	if (bitmap->storage.file) {
1102	pr_warn("%s: kicking failed bitmap file %pD4 from array!\n",
1103	bmname(bitmap), bitmap->storage.file);
1104
1105	} else
1106	pr_warn("%s: disabling internal bitmap due to errors\n",
1107	bmname(bitmap));
1108	}
1109	}
1110
1111	enum bitmap_page_attr {
1112	BITMAP_PAGE_DIRTY = 0, /* there are set bits that need to be synced */
1113	BITMAP_PAGE_PENDING = 1, /* there are bits that are being cleaned.
1114	* i.e. counter is 1 or 2. */
1115	BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
1116	};
1117
1118	static inline void set_page_attr(struct bitmap *bitmap, int pnum,
1119	enum bitmap_page_attr attr)
1120	{
1121	set_bit(nr: (pnum<<2) + attr, addr: bitmap->storage.filemap_attr);
1122	}
1123
1124	static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
1125	enum bitmap_page_attr attr)
1126	{
1127	clear_bit(nr: (pnum<<2) + attr, addr: bitmap->storage.filemap_attr);
1128	}
1129
1130	static inline int test_page_attr(struct bitmap *bitmap, int pnum,
1131	enum bitmap_page_attr attr)
1132	{
1133	return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
1134	}
1135
1136	static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
1137	enum bitmap_page_attr attr)
1138	{
1139	return test_and_clear_bit(nr: (pnum<<2) + attr,
1140	addr: bitmap->storage.filemap_attr);
1141	}
1142	/*
1143	* bitmap_file_set_bit -- called before performing a write to the md device
1144	* to set (and eventually sync) a particular bit in the bitmap file
1145	*
1146	* we set the bit immediately, then we record the page number so that
1147	* when an unplug occurs, we can flush the dirty pages out to disk
1148	*/
1149	static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
1150	{
1151	unsigned long bit;
1152	struct page *page;
1153	void *kaddr;
1154	unsigned long chunk = block >> bitmap->counts.chunkshift;
1155	struct bitmap_storage *store = &bitmap->storage;
1156	unsigned long index = file_page_index(store, chunk);
1157	unsigned long node_offset = 0;
1158
1159	index += store->sb_index;
1160	if (mddev_is_clustered(mddev: bitmap->mddev))
1161	node_offset = bitmap->cluster_slot * store->file_pages;
1162
1163	page = filemap_get_page(store: &bitmap->storage, chunk);
1164	if (!page)
1165	return;
1166	bit = file_page_offset(store: &bitmap->storage, chunk);
1167
1168	/* set the bit */
1169	kaddr = kmap_local_page(page);
1170	if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1171	set_bit(nr: bit, addr: kaddr);
1172	else
1173	set_bit_le(nr: bit, addr: kaddr);
1174	kunmap_local(kaddr);
1175	pr_debug("set file bit %lu page %lu\n", bit, index);
1176	/* record page number so it gets flushed to disk when unplug occurs */
1177	set_page_attr(bitmap, pnum: index - node_offset, attr: BITMAP_PAGE_DIRTY);
1178	}
1179
1180	static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
1181	{
1182	unsigned long bit;
1183	struct page *page;
1184	void *paddr;
1185	unsigned long chunk = block >> bitmap->counts.chunkshift;
1186	struct bitmap_storage *store = &bitmap->storage;
1187	unsigned long index = file_page_index(store, chunk);
1188	unsigned long node_offset = 0;
1189
1190	index += store->sb_index;
1191	if (mddev_is_clustered(mddev: bitmap->mddev))
1192	node_offset = bitmap->cluster_slot * store->file_pages;
1193
1194	page = filemap_get_page(store: &bitmap->storage, chunk);
1195	if (!page)
1196	return;
1197	bit = file_page_offset(store: &bitmap->storage, chunk);
1198	paddr = kmap_local_page(page);
1199	if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1200	clear_bit(nr: bit, addr: paddr);
1201	else
1202	clear_bit_le(nr: bit, addr: paddr);
1203	kunmap_local(paddr);
1204	if (!test_page_attr(bitmap, pnum: index - node_offset, attr: BITMAP_PAGE_NEEDWRITE)) {
1205	set_page_attr(bitmap, pnum: index - node_offset, attr: BITMAP_PAGE_PENDING);
1206	bitmap->allclean = 0;
1207	}
1208	}
1209
1210	static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
1211	{
1212	unsigned long bit;
1213	struct page *page;
1214	void *paddr;
1215	unsigned long chunk = block >> bitmap->counts.chunkshift;
1216	int set = 0;
1217
1218	page = filemap_get_page(store: &bitmap->storage, chunk);
1219	if (!page)
1220	return -EINVAL;
1221	bit = file_page_offset(store: &bitmap->storage, chunk);
1222	paddr = kmap_local_page(page);
1223	if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1224	set = test_bit(bit, paddr);
1225	else
1226	set = test_bit_le(nr: bit, addr: paddr);
1227	kunmap_local(paddr);
1228	return set;
1229	}
1230
1231	/* this gets called when the md device is ready to unplug its underlying
1232	* (slave) device queues -- before we let any writes go down, we need to
1233	* sync the dirty pages of the bitmap file to disk */
1234	static void __bitmap_unplug(struct bitmap *bitmap)
1235	{
1236	unsigned long i;
1237	int dirty, need_write;
1238	int writing = 0;
1239
1240	if (!bitmap_enabled(data: bitmap, flush: true))
1241	return;
1242
1243	/* look at each page to see if there are any set bits that need to be
1244	* flushed out to disk */
1245	for (i = 0; i < bitmap->storage.file_pages; i++) {
1246	dirty = test_and_clear_page_attr(bitmap, pnum: i, attr: BITMAP_PAGE_DIRTY);
1247	need_write = test_and_clear_page_attr(bitmap, pnum: i,
1248	attr: BITMAP_PAGE_NEEDWRITE);
1249	if (dirty || need_write) {
1250	if (!writing) {
1251	md_bitmap_wait_writes(bitmap);
1252	mddev_add_trace_msg(bitmap->mddev,
1253	"md bitmap_unplug");
1254	}
1255	clear_page_attr(bitmap, pnum: i, attr: BITMAP_PAGE_PENDING);
1256	filemap_write_page(bitmap, pg_index: i, wait: false);
1257	writing = 1;
1258	}
1259	}
1260	if (writing)
1261	md_bitmap_wait_writes(bitmap);
1262
1263	if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1264	md_bitmap_file_kick(bitmap);
1265	}
1266
1267	struct bitmap_unplug_work {
1268	struct work_struct work;
1269	struct bitmap *bitmap;
1270	struct completion *done;
1271	};
1272
1273	static void md_bitmap_unplug_fn(struct work_struct *work)
1274	{
1275	struct bitmap_unplug_work *unplug_work =
1276	container_of(work, struct bitmap_unplug_work, work);
1277
1278	__bitmap_unplug(bitmap: unplug_work->bitmap);
1279	complete(unplug_work->done);
1280	}
1281
1282	static void bitmap_unplug_async(struct bitmap *bitmap)
1283	{
1284	DECLARE_COMPLETION_ONSTACK(done);
1285	struct bitmap_unplug_work unplug_work;
1286
1287	INIT_WORK_ONSTACK(&unplug_work.work, md_bitmap_unplug_fn);
1288	unplug_work.bitmap = bitmap;
1289	unplug_work.done = &done;
1290
1291	queue_work(wq: md_bitmap_wq, work: &unplug_work.work);
1292	wait_for_completion(&done);
1293	destroy_work_on_stack(work: &unplug_work.work);
1294	}
1295
1296	static void bitmap_unplug(struct mddev *mddev, bool sync)
1297	{
1298	struct bitmap *bitmap = mddev->bitmap;
1299
1300	if (!bitmap)
1301	return;
1302
1303	if (sync)
1304	__bitmap_unplug(bitmap);
1305	else
1306	bitmap_unplug_async(bitmap);
1307	}
1308
1309	static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
1310
1311	/*
1312	* Initialize the in-memory bitmap from the on-disk bitmap and set up the memory
1313	* mapping of the bitmap file.
1314	*
1315	* Special case: If there's no bitmap file, or if the bitmap file had been
1316	* previously kicked from the array, we mark all the bits as 1's in order to
1317	* cause a full resync.
1318	*
1319	* We ignore all bits for sectors that end earlier than 'start'.
1320	* This is used when reading an out-of-date bitmap.
1321	*/
1322	static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
1323	{
1324	bool outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
1325	struct mddev *mddev = bitmap->mddev;
1326	unsigned long chunks = bitmap->counts.chunks;
1327	struct bitmap_storage *store = &bitmap->storage;
1328	struct file *file = store->file;
1329	unsigned long node_offset = 0;
1330	unsigned long bit_cnt = 0;
1331	unsigned long i;
1332	int ret;
1333
1334	if (!file && !mddev->bitmap_info.offset) {
1335	/* No permanent bitmap - fill with '1s'. */
1336	store->filemap = NULL;
1337	store->file_pages = 0;
1338	for (i = 0; i < chunks ; i++) {
1339	/* if the disk bit is set, set the memory bit */
1340	int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
1341	>= start);
1342	md_bitmap_set_memory_bits(bitmap,
1343	offset: (sector_t)i << bitmap->counts.chunkshift,
1344	needed);
1345	}
1346	return 0;
1347	}
1348
1349	if (file && i_size_read(inode: file->f_mapping->host) < store->bytes) {
1350	pr_warn("%s: bitmap file too short %lu < %lu\n",
1351	bmname(bitmap),
1352	(unsigned long) i_size_read(file->f_mapping->host),
1353	store->bytes);
1354	ret = -ENOSPC;
1355	goto err;
1356	}
1357
1358	if (mddev_is_clustered(mddev))
1359	node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
1360
1361	for (i = 0; i < store->file_pages; i++) {
1362	struct page *page = store->filemap[i];
1363	int count;
1364
1365	/* unmap the old page, we're done with it */
1366	if (i == store->file_pages - 1)
1367	count = store->bytes - i * PAGE_SIZE;
1368	else
1369	count = PAGE_SIZE;
1370
1371	if (file)
1372	ret = read_file_page(file, index: i, bitmap, count, page);
1373	else
1374	ret = read_sb_page(mddev, offset: 0, page, index: i + node_offset,
1375	size: count);
1376	if (ret)
1377	goto err;
1378	}
1379
1380	if (outofdate) {
1381	pr_warn("%s: bitmap file is out of date, doing full recovery\n",
1382	bmname(bitmap));
1383
1384	for (i = 0; i < store->file_pages; i++) {
1385	struct page *page = store->filemap[i];
1386	unsigned long offset = 0;
1387	void *paddr;
1388
1389	if (i == 0 && !mddev->bitmap_info.external)
1390	offset = sizeof(bitmap_super_t);
1391
1392	/*
1393	* If the bitmap is out of date, dirty the whole page
1394	* and write it out
1395	*/
1396	paddr = kmap_local_page(page);
1397	memset(paddr + offset, 0xff, PAGE_SIZE - offset);
1398	kunmap_local(paddr);
1399
1400	filemap_write_page(bitmap, pg_index: i, wait: true);
1401	if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags)) {
1402	ret = -EIO;
1403	goto err;
1404	}
1405	}
1406	}
1407
1408	for (i = 0; i < chunks; i++) {
1409	struct page *page = filemap_get_page(store: &bitmap->storage, chunk: i);
1410	unsigned long bit = file_page_offset(store: &bitmap->storage, chunk: i);
1411	void *paddr;
1412	bool was_set;
1413
1414	paddr = kmap_local_page(page);
1415	if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1416	was_set = test_bit(bit, paddr);
1417	else
1418	was_set = test_bit_le(nr: bit, addr: paddr);
1419	kunmap_local(paddr);
1420
1421	if (was_set) {
1422	/* if the disk bit is set, set the memory bit */
1423	int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1424	>= start);
1425	md_bitmap_set_memory_bits(bitmap,
1426	offset: (sector_t)i << bitmap->counts.chunkshift,
1427	needed);
1428	bit_cnt++;
1429	}
1430	}
1431
1432	pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
1433	bmname(bitmap), store->file_pages,
1434	bit_cnt, chunks);
1435
1436	return 0;
1437
1438	err:
1439	pr_warn("%s: bitmap initialisation failed: %d\n",
1440	bmname(bitmap), ret);
1441	return ret;
1442	}
1443
1444	/* just flag bitmap pages as needing to be written. */
1445	static void bitmap_write_all(struct mddev *mddev)
1446	{
1447	int i;
1448	struct bitmap *bitmap = mddev->bitmap;
1449
1450	if (!bitmap || !bitmap->storage.filemap)
1451	return;
1452
1453	/* Only one copy, so nothing needed */
1454	if (bitmap->storage.file)
1455	return;
1456
1457	for (i = 0; i < bitmap->storage.file_pages; i++)
1458	set_page_attr(bitmap, pnum: i, attr: BITMAP_PAGE_NEEDWRITE);
1459	bitmap->allclean = 0;
1460	}
1461
1462	static void md_bitmap_count_page(struct bitmap_counts *bitmap,
1463	sector_t offset, int inc)
1464	{
1465	sector_t chunk = offset >> bitmap->chunkshift;
1466	unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1467	bitmap->bp[page].count += inc;
1468	md_bitmap_checkfree(bitmap, page);
1469	}
1470
1471	static void md_bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1472	{
1473	sector_t chunk = offset >> bitmap->chunkshift;
1474	unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1475	struct bitmap_page *bp = &bitmap->bp[page];
1476
1477	if (!bp->pending)
1478	bp->pending = 1;
1479	}
1480
1481	static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1482	sector_t offset, sector_t *blocks,
1483	int create);
1484
1485	static void mddev_set_timeout(struct mddev *mddev, unsigned long timeout,
1486	bool force)
1487	{
1488	struct md_thread *thread;
1489
1490	rcu_read_lock();
1491	thread = rcu_dereference(mddev->thread);
1492
1493	if (!thread)
1494	goto out;
1495
1496	if (force || thread->timeout < MAX_SCHEDULE_TIMEOUT)
1497	thread->timeout = timeout;
1498
1499	out:
1500	rcu_read_unlock();
1501	}
1502
1503	/*
1504	* bitmap daemon -- periodically wakes up to clean bits and flush pages
1505	* out to disk
1506	*/
1507	static void bitmap_daemon_work(struct mddev *mddev)
1508	{
1509	struct bitmap *bitmap;
1510	unsigned long j;
1511	unsigned long nextpage;
1512	sector_t blocks;
1513	struct bitmap_counts *counts;
1514
1515	/* Use a mutex to guard daemon_work against
1516	* bitmap_destroy.
1517	*/
1518	mutex_lock(&mddev->bitmap_info.mutex);
1519	bitmap = mddev->bitmap;
1520	if (bitmap == NULL) {
1521	mutex_unlock(lock: &mddev->bitmap_info.mutex);
1522	return;
1523	}
1524	if (time_before(jiffies, bitmap->daemon_lastrun
1525	+ mddev->bitmap_info.daemon_sleep))
1526	goto done;
1527
1528	bitmap->daemon_lastrun = jiffies;
1529	if (bitmap->allclean) {
1530	mddev_set_timeout(mddev, MAX_SCHEDULE_TIMEOUT, force: true);
1531	goto done;
1532	}
1533	bitmap->allclean = 1;
1534
1535	mddev_add_trace_msg(bitmap->mddev, "md bitmap_daemon_work");
1536
1537	/* Any file-page which is PENDING now needs to be written.
1538	* So set NEEDWRITE now, then after we make any last-minute changes
1539	* we will write it.
1540	*/
1541	for (j = 0; j < bitmap->storage.file_pages; j++)
1542	if (test_and_clear_page_attr(bitmap, pnum: j,
1543	attr: BITMAP_PAGE_PENDING))
1544	set_page_attr(bitmap, pnum: j,
1545	attr: BITMAP_PAGE_NEEDWRITE);
1546
1547	if (bitmap->need_sync &&
1548	mddev->bitmap_info.external == 0) {
1549	/* Arrange for superblock update as well as
1550	* other changes */
1551	bitmap_super_t *sb;
1552	bitmap->need_sync = 0;
1553	if (bitmap->storage.filemap) {
1554	sb = kmap_local_page(page: bitmap->storage.sb_page);
1555	sb->events_cleared =
1556	cpu_to_le64(bitmap->events_cleared);
1557	kunmap_local(sb);
1558	set_page_attr(bitmap, pnum: 0,
1559	attr: BITMAP_PAGE_NEEDWRITE);
1560	}
1561	}
1562	/* Now look at the bitmap counters and if any are '2' or '1',
1563	* decrement and handle accordingly.
1564	*/
1565	counts = &bitmap->counts;
1566	spin_lock_irq(lock: &counts->lock);
1567	nextpage = 0;
1568	for (j = 0; j < counts->chunks; j++) {
1569	bitmap_counter_t *bmc;
1570	sector_t block = (sector_t)j << counts->chunkshift;
1571
1572	if (j == nextpage) {
1573	nextpage += PAGE_COUNTER_RATIO;
1574	if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1575	j |= PAGE_COUNTER_MASK;
1576	continue;
1577	}
1578	counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1579	}
1580
1581	bmc = md_bitmap_get_counter(bitmap: counts, offset: block, blocks: &blocks, create: 0);
1582	if (!bmc) {
1583	j |= PAGE_COUNTER_MASK;
1584	continue;
1585	}
1586	if (*bmc == 1 && !bitmap->need_sync) {
1587	/* We can clear the bit */
1588	*bmc = 0;
1589	md_bitmap_count_page(bitmap: counts, offset: block, inc: -1);
1590	md_bitmap_file_clear_bit(bitmap, block);
1591	} else if (*bmc && *bmc <= 2) {
1592	*bmc = 1;
1593	md_bitmap_set_pending(bitmap: counts, offset: block);
1594	bitmap->allclean = 0;
1595	}
1596	}
1597	spin_unlock_irq(lock: &counts->lock);
1598
1599	md_bitmap_wait_writes(bitmap);
1600	/* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1601	* DIRTY pages need to be written by bitmap_unplug so it can wait
1602	* for them.
1603	* If we find any DIRTY page we stop there and let bitmap_unplug
1604	* handle all the rest. This is important in the case where
1605	* the first blocking holds the superblock and it has been updated.
1606	* We mustn't write any other blocks before the superblock.
1607	*/
1608	for (j = 0;
1609	j < bitmap->storage.file_pages
1610	&& !test_bit(BITMAP_STALE, &bitmap->flags);
1611	j++) {
1612	if (test_page_attr(bitmap, pnum: j,
1613	attr: BITMAP_PAGE_DIRTY))
1614	/* bitmap_unplug will handle the rest */
1615	break;
1616	if (bitmap->storage.filemap &&
1617	test_and_clear_page_attr(bitmap, pnum: j,
1618	attr: BITMAP_PAGE_NEEDWRITE))
1619	filemap_write_page(bitmap, pg_index: j, wait: false);
1620	}
1621
1622	done:
1623	if (bitmap->allclean == 0)
1624	mddev_set_timeout(mddev, timeout: mddev->bitmap_info.daemon_sleep, force: true);
1625	mutex_unlock(lock: &mddev->bitmap_info.mutex);
1626	}
1627
1628	static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
1629	sector_t offset, sector_t *blocks,
1630	int create)
1631	__releases(bitmap->lock)
1632	__acquires(bitmap->lock)
1633	{
1634	/* If 'create', we might release the lock and reclaim it.
1635	* The lock must have been taken with interrupts enabled.
1636	* If !create, we don't release the lock.
1637	*/
1638	sector_t chunk = offset >> bitmap->chunkshift;
1639	unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1640	unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1641	sector_t csize = ((sector_t)1) << bitmap->chunkshift;
1642	int err;
1643
1644	if (page >= bitmap->pages) {
1645	/*
1646	* This can happen if bitmap_start_sync goes beyond
1647	* End-of-device while looking for a whole page or
1648	* user set a huge number to sysfs bitmap_set_bits.
1649	*/
1650	*blocks = csize - (offset & (csize - 1));
1651	return NULL;
1652	}
1653	err = md_bitmap_checkpage(bitmap, page, create, no_hijack: 0);
1654
1655	if (bitmap->bp[page].hijacked ||
1656	bitmap->bp[page].map == NULL)
1657	csize = ((sector_t)1) << (bitmap->chunkshift +
1658	PAGE_COUNTER_SHIFT);
1659
1660	*blocks = csize - (offset & (csize - 1));
1661
1662	if (err < 0)
1663	return NULL;
1664
1665	/* now locked ... */
1666
1667	if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1668	/* should we use the first or second counter field
1669	* of the hijacked pointer? */
1670	int hi = (pageoff > PAGE_COUNTER_MASK);
1671	return &((bitmap_counter_t *)
1672	&bitmap->bp[page].map)[hi];
1673	} else /* page is allocated */
1674	return (bitmap_counter_t *)
1675	&(bitmap->bp[page].map[pageoff]);
1676	}
1677
1678	static void bitmap_start_write(struct mddev *mddev, sector_t offset,
1679	unsigned long sectors)
1680	{
1681	struct bitmap *bitmap = mddev->bitmap;
1682
1683	if (!bitmap)
1684	return;
1685
1686	while (sectors) {
1687	sector_t blocks;
1688	bitmap_counter_t *bmc;
1689
1690	spin_lock_irq(lock: &bitmap->counts.lock);
1691	bmc = md_bitmap_get_counter(bitmap: &bitmap->counts, offset, blocks: &blocks, create: 1);
1692	if (!bmc) {
1693	spin_unlock_irq(lock: &bitmap->counts.lock);
1694	return;
1695	}
1696
1697	if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1698	DEFINE_WAIT(__wait);
1699	/* note that it is safe to do the prepare_to_wait
1700	* after the test as long as we do it before dropping
1701	* the spinlock.
1702	*/
1703	prepare_to_wait(wq_head: &bitmap->overflow_wait, wq_entry: &__wait,
1704	TASK_UNINTERRUPTIBLE);
1705	spin_unlock_irq(lock: &bitmap->counts.lock);
1706	schedule();
1707	finish_wait(wq_head: &bitmap->overflow_wait, wq_entry: &__wait);
1708	continue;
1709	}
1710
1711	switch (*bmc) {
1712	case 0:
1713	md_bitmap_file_set_bit(bitmap, block: offset);
1714	md_bitmap_count_page(bitmap: &bitmap->counts, offset, inc: 1);
1715	fallthrough;
1716	case 1:
1717	*bmc = 2;
1718	}
1719
1720	(*bmc)++;
1721
1722	spin_unlock_irq(lock: &bitmap->counts.lock);
1723
1724	offset += blocks;
1725	if (sectors > blocks)
1726	sectors -= blocks;
1727	else
1728	sectors = 0;
1729	}
1730	}
1731
1732	static void bitmap_end_write(struct mddev *mddev, sector_t offset,
1733	unsigned long sectors)
1734	{
1735	struct bitmap *bitmap = mddev->bitmap;
1736
1737	if (!bitmap)
1738	return;
1739
1740	while (sectors) {
1741	sector_t blocks;
1742	unsigned long flags;
1743	bitmap_counter_t *bmc;
1744
1745	spin_lock_irqsave(&bitmap->counts.lock, flags);
1746	bmc = md_bitmap_get_counter(bitmap: &bitmap->counts, offset, blocks: &blocks, create: 0);
1747	if (!bmc) {
1748	spin_unlock_irqrestore(lock: &bitmap->counts.lock, flags);
1749	return;
1750	}
1751
1752	if (!bitmap->mddev->degraded) {
1753	if (bitmap->events_cleared < bitmap->mddev->events) {
1754	bitmap->events_cleared = bitmap->mddev->events;
1755	bitmap->need_sync = 1;
1756	sysfs_notify_dirent_safe(
1757	sd: bitmap->sysfs_can_clear);
1758	}
1759	} else if (!NEEDED(*bmc)) {
1760	*bmc |= NEEDED_MASK;
1761	}
1762
1763	if (COUNTER(*bmc) == COUNTER_MAX)
1764	wake_up(&bitmap->overflow_wait);
1765
1766	(*bmc)--;
1767	if (*bmc <= 2) {
1768	md_bitmap_set_pending(bitmap: &bitmap->counts, offset);
1769	bitmap->allclean = 0;
1770	}
1771	spin_unlock_irqrestore(lock: &bitmap->counts.lock, flags);
1772	offset += blocks;
1773	if (sectors > blocks)
1774	sectors -= blocks;
1775	else
1776	sectors = 0;
1777	}
1778	}
1779
1780	static bool __bitmap_start_sync(struct bitmap *bitmap, sector_t offset,
1781	sector_t *blocks, bool degraded)
1782	{
1783	bitmap_counter_t *bmc;
1784	bool rv = false;
1785
1786	spin_lock_irq(lock: &bitmap->counts.lock);
1787	bmc = md_bitmap_get_counter(bitmap: &bitmap->counts, offset, blocks, create: 0);
1788	if (bmc) {
1789	/* locked */
1790	if (RESYNC(*bmc)) {
1791	rv = true;
1792	} else if (NEEDED(*bmc)) {
1793	rv = true;
1794	if (!degraded) { /* don't set/clear bits if degraded */
1795	*bmc |= RESYNC_MASK;
1796	*bmc &= ~NEEDED_MASK;
1797	}
1798	}
1799	}
1800	spin_unlock_irq(lock: &bitmap->counts.lock);
1801
1802	return rv;
1803	}
1804
1805	static bool bitmap_start_sync(struct mddev *mddev, sector_t offset,
1806	sector_t *blocks, bool degraded)
1807	{
1808	/* bitmap_start_sync must always report on multiples of whole
1809	* pages, otherwise resync (which is very PAGE_SIZE based) will
1810	* get confused.
1811	* So call __bitmap_start_sync repeatedly (if needed) until
1812	* At least PAGE_SIZE>>9 blocks are covered.
1813	* Return the 'or' of the result.
1814	*/
1815	bool rv = false;
1816	sector_t blocks1;
1817
1818	*blocks = 0;
1819	while (*blocks < (PAGE_SIZE>>9)) {
1820	rv |= __bitmap_start_sync(bitmap: mddev->bitmap, offset,
1821	blocks: &blocks1, degraded);
1822	offset += blocks1;
1823	*blocks += blocks1;
1824	}
1825
1826	return rv;
1827	}
1828
1829	static void __bitmap_end_sync(struct bitmap *bitmap, sector_t offset,
1830	sector_t *blocks, bool aborted)
1831	{
1832	bitmap_counter_t *bmc;
1833	unsigned long flags;
1834
1835	spin_lock_irqsave(&bitmap->counts.lock, flags);
1836	bmc = md_bitmap_get_counter(bitmap: &bitmap->counts, offset, blocks, create: 0);
1837	if (bmc == NULL)
1838	goto unlock;
1839	/* locked */
1840	if (RESYNC(*bmc)) {
1841	*bmc &= ~RESYNC_MASK;
1842
1843	if (!NEEDED(*bmc) && aborted)
1844	*bmc |= NEEDED_MASK;
1845	else {
1846	if (*bmc <= 2) {
1847	md_bitmap_set_pending(bitmap: &bitmap->counts, offset);
1848	bitmap->allclean = 0;
1849	}
1850	}
1851	}
1852	unlock:
1853	spin_unlock_irqrestore(lock: &bitmap->counts.lock, flags);
1854	}
1855
1856	static void bitmap_end_sync(struct mddev *mddev, sector_t offset,
1857	sector_t *blocks)
1858	{
1859	__bitmap_end_sync(bitmap: mddev->bitmap, offset, blocks, aborted: true);
1860	}
1861
1862	static void bitmap_close_sync(struct mddev *mddev)
1863	{
1864	/* Sync has finished, and any bitmap chunks that weren't synced
1865	* properly have been aborted. It remains to us to clear the
1866	* RESYNC bit wherever it is still on
1867	*/
1868	sector_t sector = 0;
1869	sector_t blocks;
1870	struct bitmap *bitmap = mddev->bitmap;
1871
1872	if (!bitmap)
1873	return;
1874
1875	while (sector < bitmap->mddev->resync_max_sectors) {
1876	__bitmap_end_sync(bitmap, offset: sector, blocks: &blocks, aborted: false);
1877	sector += blocks;
1878	}
1879	}
1880
1881	static void bitmap_cond_end_sync(struct mddev *mddev, sector_t sector,
1882	bool force)
1883	{
1884	sector_t s = 0;
1885	sector_t blocks;
1886	struct bitmap *bitmap = mddev->bitmap;
1887
1888	if (!bitmap)
1889	return;
1890	if (sector == 0) {
1891	bitmap->last_end_sync = jiffies;
1892	return;
1893	}
1894	if (!force && time_before(jiffies, (bitmap->last_end_sync
1895	+ bitmap->mddev->bitmap_info.daemon_sleep)))
1896	return;
1897	wait_event(bitmap->mddev->recovery_wait,
1898	atomic_read(&bitmap->mddev->recovery_active) == 0);
1899
1900	bitmap->mddev->curr_resync_completed = sector;
1901	set_bit(nr: MD_SB_CHANGE_CLEAN, addr: &bitmap->mddev->sb_flags);
1902	sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1903	s = 0;
1904	while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1905	__bitmap_end_sync(bitmap, offset: s, blocks: &blocks, aborted: false);
1906	s += blocks;
1907	}
1908	bitmap->last_end_sync = jiffies;
1909	sysfs_notify_dirent_safe(sd: bitmap->mddev->sysfs_completed);
1910	}
1911
1912	static void bitmap_sync_with_cluster(struct mddev *mddev,
1913	sector_t old_lo, sector_t old_hi,
1914	sector_t new_lo, sector_t new_hi)
1915	{
1916	struct bitmap *bitmap = mddev->bitmap;
1917	sector_t sector, blocks = 0;
1918
1919	for (sector = old_lo; sector < new_lo; ) {
1920	__bitmap_end_sync(bitmap, offset: sector, blocks: &blocks, aborted: false);
1921	sector += blocks;
1922	}
1923	WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
1924
1925	for (sector = old_hi; sector < new_hi; ) {
1926	bitmap_start_sync(mddev, offset: sector, blocks: &blocks, degraded: false);
1927	sector += blocks;
1928	}
1929	WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
1930	}
1931
1932	static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1933	{
1934	/* For each chunk covered by any of these sectors, set the
1935	* counter to 2 and possibly set resync_needed. They should all
1936	* be 0 at this point
1937	*/
1938
1939	sector_t secs;
1940	bitmap_counter_t *bmc;
1941	spin_lock_irq(lock: &bitmap->counts.lock);
1942	bmc = md_bitmap_get_counter(bitmap: &bitmap->counts, offset, blocks: &secs, create: 1);
1943	if (!bmc) {
1944	spin_unlock_irq(lock: &bitmap->counts.lock);
1945	return;
1946	}
1947	if (!*bmc) {
1948	*bmc = 2;
1949	md_bitmap_count_page(bitmap: &bitmap->counts, offset, inc: 1);
1950	md_bitmap_set_pending(bitmap: &bitmap->counts, offset);
1951	bitmap->allclean = 0;
1952	}
1953	if (needed)
1954	*bmc |= NEEDED_MASK;
1955	spin_unlock_irq(lock: &bitmap->counts.lock);
1956	}
1957
1958	/* dirty the memory and file bits for bitmap chunks "s" to "e" */
1959	static void bitmap_dirty_bits(struct mddev *mddev, unsigned long s,
1960	unsigned long e)
1961	{
1962	unsigned long chunk;
1963	struct bitmap *bitmap = mddev->bitmap;
1964
1965	if (!bitmap)
1966	return;
1967
1968	for (chunk = s; chunk <= e; chunk++) {
1969	sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1970
1971	md_bitmap_set_memory_bits(bitmap, offset: sec, needed: 1);
1972	md_bitmap_file_set_bit(bitmap, block: sec);
1973	if (sec < bitmap->mddev->resync_offset)
1974	/* We are asserting that the array is dirty,
1975	* so move the resync_offset address back so
1976	* that it is obvious that it is dirty
1977	*/
1978	bitmap->mddev->resync_offset = sec;
1979	}
1980	}
1981
1982	static void bitmap_flush(struct mddev *mddev)
1983	{
1984	struct bitmap *bitmap = mddev->bitmap;
1985	long sleep;
1986
1987	if (!bitmap) /* there was no bitmap */
1988	return;
1989
1990	/* run the daemon_work three time to ensure everything is flushed
1991	* that can be
1992	*/
1993	sleep = mddev->bitmap_info.daemon_sleep * 2;
1994	bitmap->daemon_lastrun -= sleep;
1995	bitmap_daemon_work(mddev);
1996	bitmap->daemon_lastrun -= sleep;
1997	bitmap_daemon_work(mddev);
1998	bitmap->daemon_lastrun -= sleep;
1999	bitmap_daemon_work(mddev);
2000	if (mddev->bitmap_info.external)
2001	md_super_wait(mddev);
2002	bitmap_update_sb(data: bitmap);
2003	}
2004
2005	static void md_bitmap_free(void *data)
2006	{
2007	unsigned long k, pages;
2008	struct bitmap_page *bp;
2009	struct bitmap *bitmap = data;
2010
2011	if (!bitmap) /* there was no bitmap */
2012	return;
2013
2014	if (bitmap->sysfs_can_clear)
2015	sysfs_put(kn: bitmap->sysfs_can_clear);
2016
2017	if (mddev_is_clustered(mddev: bitmap->mddev) && bitmap->mddev->cluster_info &&
2018	bitmap->cluster_slot == bitmap->mddev->cluster_ops->slot_number(bitmap->mddev))
2019	md_cluster_stop(mddev: bitmap->mddev);
2020
2021	/* Shouldn't be needed - but just in case.... */
2022	wait_event(bitmap->write_wait,
2023	atomic_read(&bitmap->pending_writes) == 0);
2024
2025	/* release the bitmap file */
2026	md_bitmap_file_unmap(store: &bitmap->storage);
2027
2028	bp = bitmap->counts.bp;
2029	pages = bitmap->counts.pages;
2030
2031	/* free all allocated memory */
2032
2033	if (bp) /* deallocate the page memory */
2034	for (k = 0; k < pages; k++)
2035	if (bp[k].map && !bp[k].hijacked)
2036	kfree(objp: bp[k].map);
2037	kfree(objp: bp);
2038	kfree(objp: bitmap);
2039	}
2040
2041	static void bitmap_start_behind_write(struct mddev *mddev)
2042	{
2043	struct bitmap *bitmap = mddev->bitmap;
2044	int bw;
2045
2046	atomic_inc(v: &bitmap->behind_writes);
2047	bw = atomic_read(v: &bitmap->behind_writes);
2048	if (bw > bitmap->behind_writes_used)
2049	bitmap->behind_writes_used = bw;
2050
2051	pr_debug("inc write-behind count %d/%lu\n",
2052	bw, bitmap->mddev->bitmap_info.max_write_behind);
2053	}
2054
2055	static void bitmap_end_behind_write(struct mddev *mddev)
2056	{
2057	struct bitmap *bitmap = mddev->bitmap;
2058
2059	if (atomic_dec_and_test(v: &bitmap->behind_writes))
2060	wake_up(&bitmap->behind_wait);
2061	pr_debug("dec write-behind count %d/%lu\n",
2062	atomic_read(&bitmap->behind_writes),
2063	bitmap->mddev->bitmap_info.max_write_behind);
2064	}
2065
2066	static void bitmap_wait_behind_writes(struct mddev *mddev)
2067	{
2068	struct bitmap *bitmap = mddev->bitmap;
2069
2070	/* wait for behind writes to complete */
2071	if (bitmap && atomic_read(v: &bitmap->behind_writes) > 0) {
2072	pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
2073	mdname(mddev));
2074	/* need to kick something here to make sure I/O goes? */
2075	wait_event(bitmap->behind_wait,
2076	atomic_read(&bitmap->behind_writes) == 0);
2077	}
2078	}
2079
2080	static void bitmap_destroy(struct mddev *mddev)
2081	{
2082	struct bitmap *bitmap = mddev->bitmap;
2083
2084	if (!bitmap) /* there was no bitmap */
2085	return;
2086
2087	bitmap_wait_behind_writes(mddev);
2088	if (!mddev->serialize_policy)
2089	mddev_destroy_serial_pool(mddev, NULL);
2090
2091	mutex_lock(&mddev->bitmap_info.mutex);
2092	spin_lock(lock: &mddev->lock);
2093	mddev->bitmap = NULL; /* disconnect from the md device */
2094	spin_unlock(lock: &mddev->lock);
2095	mutex_unlock(lock: &mddev->bitmap_info.mutex);
2096	mddev_set_timeout(mddev, MAX_SCHEDULE_TIMEOUT, force: true);
2097
2098	md_bitmap_free(data: bitmap);
2099	}
2100
2101	/*
2102	* initialize the bitmap structure
2103	* if this returns an error, bitmap_destroy must be called to do clean up
2104	* once mddev->bitmap is set
2105	*/
2106	static struct bitmap *__bitmap_create(struct mddev *mddev, int slot)
2107	{
2108	struct bitmap *bitmap;
2109	sector_t blocks = mddev->resync_max_sectors;
2110	struct file *file = mddev->bitmap_info.file;
2111	int err;
2112	struct kernfs_node *bm = NULL;
2113
2114	BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
2115
2116	BUG_ON(file && mddev->bitmap_info.offset);
2117
2118	if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
2119	pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
2120	mdname(mddev));
2121	return ERR_PTR(error: -EBUSY);
2122	}
2123
2124	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
2125	if (!bitmap)
2126	return ERR_PTR(error: -ENOMEM);
2127
2128	spin_lock_init(&bitmap->counts.lock);
2129	atomic_set(v: &bitmap->pending_writes, i: 0);
2130	init_waitqueue_head(&bitmap->write_wait);
2131	init_waitqueue_head(&bitmap->overflow_wait);
2132	init_waitqueue_head(&bitmap->behind_wait);
2133
2134	bitmap->mddev = mddev;
2135	bitmap->cluster_slot = slot;
2136
2137	if (mddev->kobj.sd)
2138	bm = sysfs_get_dirent(parent: mddev->kobj.sd, name: "bitmap");
2139	if (bm) {
2140	bitmap->sysfs_can_clear = sysfs_get_dirent(parent: bm, name: "can_clear");
2141	sysfs_put(kn: bm);
2142	} else
2143	bitmap->sysfs_can_clear = NULL;
2144
2145	bitmap->storage.file = file;
2146	if (file) {
2147	get_file(f: file);
2148	/* As future accesses to this file will use bmap,
2149	* and bypass the page cache, we must sync the file
2150	* first.
2151	*/
2152	vfs_fsync(file, datasync: 1);
2153	}
2154	/* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
2155	if (!mddev->bitmap_info.external) {
2156	/*
2157	* If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
2158	* instructing us to create a new on-disk bitmap instance.
2159	*/
2160	if (test_and_clear_bit(nr: MD_ARRAY_FIRST_USE, addr: &mddev->flags))
2161	err = md_bitmap_new_disk_sb(bitmap);
2162	else
2163	err = md_bitmap_read_sb(bitmap);
2164	} else {
2165	err = 0;
2166	if (mddev->bitmap_info.chunksize == 0 ||
2167	mddev->bitmap_info.daemon_sleep == 0)
2168	/* chunksize and time_base need to be
2169	* set first. */
2170	err = -EINVAL;
2171	}
2172	if (err)
2173	goto error;
2174
2175	bitmap->daemon_lastrun = jiffies;
2176	err = __bitmap_resize(bitmap, blocks, chunksize: mddev->bitmap_info.chunksize,
2177	init: true);
2178	if (err)
2179	goto error;
2180
2181	pr_debug("created bitmap (%lu pages) for device %s\n",
2182	bitmap->counts.pages, bmname(bitmap));
2183
2184	err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
2185	if (err)
2186	goto error;
2187
2188	return bitmap;
2189	error:
2190	md_bitmap_free(data: bitmap);
2191	return ERR_PTR(error: err);
2192	}
2193
2194	static int bitmap_create(struct mddev *mddev)
2195	{
2196	struct bitmap *bitmap = __bitmap_create(mddev, slot: -1);
2197
2198	if (IS_ERR(ptr: bitmap))
2199	return PTR_ERR(ptr: bitmap);
2200
2201	mddev->bitmap = bitmap;
2202	return 0;
2203	}
2204
2205	static int bitmap_load(struct mddev *mddev)
2206	{
2207	int err = 0;
2208	sector_t start = 0;
2209	sector_t sector = 0;
2210	struct bitmap *bitmap = mddev->bitmap;
2211	struct md_rdev *rdev;
2212
2213	if (!bitmap)
2214	goto out;
2215
2216	rdev_for_each(rdev, mddev)
2217	mddev_create_serial_pool(mddev, rdev);
2218
2219	if (mddev_is_clustered(mddev))
2220	mddev->cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
2221
2222	/* Clear out old bitmap info first: Either there is none, or we
2223	* are resuming after someone else has possibly changed things,
2224	* so we should forget old cached info.
2225	* All chunks should be clean, but some might need_sync.
2226	*/
2227	while (sector < mddev->resync_max_sectors) {
2228	sector_t blocks;
2229	bitmap_start_sync(mddev, offset: sector, blocks: &blocks, degraded: false);
2230	sector += blocks;
2231	}
2232	bitmap_close_sync(mddev);
2233
2234	if (mddev->degraded == 0
2235	|| bitmap->events_cleared == mddev->events)
2236	/* no need to keep dirty bits to optimise a
2237	* re-add of a missing device */
2238	start = mddev->resync_offset;
2239
2240	mutex_lock(&mddev->bitmap_info.mutex);
2241	err = md_bitmap_init_from_disk(bitmap, start);
2242	mutex_unlock(lock: &mddev->bitmap_info.mutex);
2243
2244	if (err)
2245	goto out;
2246	clear_bit(nr: BITMAP_STALE, addr: &bitmap->flags);
2247
2248	/* Kick recovery in case any bits were set */
2249	set_bit(nr: MD_RECOVERY_NEEDED, addr: &bitmap->mddev->recovery);
2250
2251	mddev_set_timeout(mddev, timeout: mddev->bitmap_info.daemon_sleep, force: true);
2252	md_wakeup_thread(mddev->thread);
2253
2254	bitmap_update_sb(data: bitmap);
2255
2256	if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
2257	err = -EIO;
2258	out:
2259	return err;
2260	}
2261
2262	/* caller need to free returned bitmap with md_bitmap_free() */
2263	static void *bitmap_get_from_slot(struct mddev *mddev, int slot)
2264	{
2265	int rv = 0;
2266	struct bitmap *bitmap;
2267
2268	bitmap = __bitmap_create(mddev, slot);
2269	if (IS_ERR(ptr: bitmap)) {
2270	rv = PTR_ERR(ptr: bitmap);
2271	return ERR_PTR(error: rv);
2272	}
2273
2274	rv = md_bitmap_init_from_disk(bitmap, start: 0);
2275	if (rv) {
2276	md_bitmap_free(data: bitmap);
2277	return ERR_PTR(error: rv);
2278	}
2279
2280	return bitmap;
2281	}
2282
2283	/* Loads the bitmap associated with slot and copies the resync information
2284	* to our bitmap
2285	*/
2286	static int bitmap_copy_from_slot(struct mddev *mddev, int slot, sector_t *low,
2287	sector_t *high, bool clear_bits)
2288	{
2289	int rv = 0, i, j;
2290	sector_t block, lo = 0, hi = 0;
2291	struct bitmap_counts *counts;
2292	struct bitmap *bitmap;
2293
2294	bitmap = bitmap_get_from_slot(mddev, slot);
2295	if (IS_ERR(ptr: bitmap)) {
2296	pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
2297	return -1;
2298	}
2299
2300	counts = &bitmap->counts;
2301	for (j = 0; j < counts->chunks; j++) {
2302	block = (sector_t)j << counts->chunkshift;
2303	if (md_bitmap_file_test_bit(bitmap, block)) {
2304	if (!lo)
2305	lo = block;
2306	hi = block;
2307	md_bitmap_file_clear_bit(bitmap, block);
2308	md_bitmap_set_memory_bits(bitmap: mddev->bitmap, offset: block, needed: 1);
2309	md_bitmap_file_set_bit(bitmap: mddev->bitmap, block);
2310	}
2311	}
2312
2313	if (clear_bits) {
2314	bitmap_update_sb(data: bitmap);
2315	/* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
2316	* BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
2317	for (i = 0; i < bitmap->storage.file_pages; i++)
2318	if (test_page_attr(bitmap, pnum: i, attr: BITMAP_PAGE_PENDING))
2319	set_page_attr(bitmap, pnum: i, attr: BITMAP_PAGE_NEEDWRITE);
2320	__bitmap_unplug(bitmap);
2321	}
2322	__bitmap_unplug(bitmap: mddev->bitmap);
2323	*low = lo;
2324	*high = hi;
2325	md_bitmap_free(data: bitmap);
2326
2327	return rv;
2328	}
2329
2330	static void bitmap_set_pages(void *data, unsigned long pages)
2331	{
2332	struct bitmap *bitmap = data;
2333
2334	bitmap->counts.pages = pages;
2335	}
2336
2337	static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)
2338	{
2339	struct bitmap_storage *storage;
2340	struct bitmap_counts *counts;
2341	struct bitmap *bitmap = data;
2342	bitmap_super_t *sb;
2343
2344	if (!bitmap)
2345	return -ENOENT;
2346	if (!bitmap->storage.sb_page)
2347	return -EINVAL;
2348	sb = kmap_local_page(page: bitmap->storage.sb_page);
2349	stats->sync_size = le64_to_cpu(sb->sync_size);
2350	kunmap_local(sb);
2351
2352	counts = &bitmap->counts;
2353	stats->missing_pages = counts->missing_pages;
2354	stats->pages = counts->pages;
2355
2356	storage = &bitmap->storage;
2357	stats->file_pages = storage->file_pages;
2358	stats->file = storage->file;
2359
2360	stats->behind_writes = atomic_read(v: &bitmap->behind_writes);
2361	stats->behind_wait = wq_has_sleeper(wq_head: &bitmap->behind_wait);
2362	stats->events_cleared = bitmap->events_cleared;
2363	return 0;
2364	}
2365
2366	static int __bitmap_resize(struct bitmap *bitmap, sector_t blocks,
2367	int chunksize, bool init)
2368	{
2369	/* If chunk_size is 0, choose an appropriate chunk size.
2370	* Then possibly allocate new storage space.
2371	* Then quiesce, copy bits, replace bitmap, and re-start
2372	*
2373	* This function is called both to set up the initial bitmap
2374	* and to resize the bitmap while the array is active.
2375	* If this happens as a result of the array being resized,
2376	* chunksize will be zero, and we need to choose a suitable
2377	* chunksize, otherwise we use what we are given.
2378	*/
2379	struct bitmap_storage store;
2380	struct bitmap_counts old_counts;
2381	unsigned long chunks;
2382	sector_t block;
2383	sector_t old_blocks, new_blocks;
2384	int chunkshift;
2385	int ret = 0;
2386	long pages;
2387	struct bitmap_page *new_bp;
2388
2389	if (bitmap->storage.file && !init) {
2390	pr_info("md: cannot resize file-based bitmap\n");
2391	return -EINVAL;
2392	}
2393
2394	if (chunksize == 0) {
2395	/* If there is enough space, leave the chunk size unchanged,
2396	* else increase by factor of two until there is enough space.
2397	*/
2398	long bytes;
2399	long space = bitmap->mddev->bitmap_info.space;
2400
2401	if (space == 0) {
2402	/* We don't know how much space there is, so limit
2403	* to current size - in sectors.
2404	*/
2405	bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
2406	if (!bitmap->mddev->bitmap_info.external)
2407	bytes += sizeof(bitmap_super_t);
2408	space = DIV_ROUND_UP(bytes, 512);
2409	bitmap->mddev->bitmap_info.space = space;
2410	}
2411	chunkshift = bitmap->counts.chunkshift;
2412	chunkshift--;
2413	do {
2414	/* 'chunkshift' is shift from block size to chunk size */
2415	chunkshift++;
2416	chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2417	bytes = DIV_ROUND_UP(chunks, 8);
2418	if (!bitmap->mddev->bitmap_info.external)
2419	bytes += sizeof(bitmap_super_t);
2420	} while (bytes > (space << 9) && (chunkshift + BITMAP_BLOCK_SHIFT) <
2421	(BITS_PER_BYTE * sizeof(((bitmap_super_t *)0)->chunksize) - 1));
2422	} else
2423	chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
2424
2425	chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
2426	memset(&store, 0, sizeof(store));
2427	if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
2428	ret = md_bitmap_storage_alloc(store: &store, chunks,
2429	with_super: !bitmap->mddev->bitmap_info.external,
2430	slot_number: mddev_is_clustered(mddev: bitmap->mddev)
2431	? bitmap->cluster_slot : 0);
2432	if (ret) {
2433	md_bitmap_file_unmap(store: &store);
2434	goto err;
2435	}
2436
2437	pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
2438
2439	new_bp = kcalloc(pages, sizeof(*new_bp), GFP_KERNEL);
2440	ret = -ENOMEM;
2441	if (!new_bp) {
2442	md_bitmap_file_unmap(store: &store);
2443	goto err;
2444	}
2445
2446	if (!init)
2447	bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
2448
2449	store.file = bitmap->storage.file;
2450	bitmap->storage.file = NULL;
2451
2452	if (store.sb_page && bitmap->storage.sb_page)
2453	memcpy(page_address(store.sb_page),
2454	page_address(bitmap->storage.sb_page),
2455	sizeof(bitmap_super_t));
2456	spin_lock_irq(lock: &bitmap->counts.lock);
2457	md_bitmap_file_unmap(store: &bitmap->storage);
2458	bitmap->storage = store;
2459
2460	old_counts = bitmap->counts;
2461	bitmap->counts.bp = new_bp;
2462	bitmap->counts.pages = pages;
2463	bitmap->counts.missing_pages = pages;
2464	bitmap->counts.chunkshift = chunkshift;
2465	bitmap->counts.chunks = chunks;
2466	bitmap->mddev->bitmap_info.chunksize = 1UL << (chunkshift +
2467	BITMAP_BLOCK_SHIFT);
2468
2469	blocks = min(old_counts.chunks << old_counts.chunkshift,
2470	chunks << chunkshift);
2471
2472	/* For cluster raid, need to pre-allocate bitmap */
2473	if (mddev_is_clustered(mddev: bitmap->mddev)) {
2474	unsigned long page;
2475	for (page = 0; page < pages; page++) {
2476	ret = md_bitmap_checkpage(bitmap: &bitmap->counts, page, create: 1, no_hijack: 1);
2477	if (ret) {
2478	unsigned long k;
2479
2480	/* deallocate the page memory */
2481	for (k = 0; k < page; k++) {
2482	kfree(objp: new_bp[k].map);
2483	}
2484	kfree(objp: new_bp);
2485
2486	/* restore some fields from old_counts */
2487	bitmap->counts.bp = old_counts.bp;
2488	bitmap->counts.pages = old_counts.pages;
2489	bitmap->counts.missing_pages = old_counts.pages;
2490	bitmap->counts.chunkshift = old_counts.chunkshift;
2491	bitmap->counts.chunks = old_counts.chunks;
2492	bitmap->mddev->bitmap_info.chunksize =
2493	1UL << (old_counts.chunkshift + BITMAP_BLOCK_SHIFT);
2494	blocks = old_counts.chunks << old_counts.chunkshift;
2495	pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
2496	break;
2497	} else
2498	bitmap->counts.bp[page].count += 1;
2499	}
2500	}
2501
2502	for (block = 0; block < blocks; ) {
2503	bitmap_counter_t *bmc_old, *bmc_new;
2504	int set;
2505
2506	bmc_old = md_bitmap_get_counter(bitmap: &old_counts, offset: block, blocks: &old_blocks, create: 0);
2507	set = bmc_old && NEEDED(*bmc_old);
2508
2509	if (set) {
2510	bmc_new = md_bitmap_get_counter(bitmap: &bitmap->counts, offset: block, blocks: &new_blocks, create: 1);
2511	if (bmc_new) {
2512	if (*bmc_new == 0) {
2513	/* need to set on-disk bits too. */
2514	sector_t end = block + new_blocks;
2515	sector_t start = block >> chunkshift;
2516
2517	start <<= chunkshift;
2518	while (start < end) {
2519	md_bitmap_file_set_bit(bitmap, block);
2520	start += 1 << chunkshift;
2521	}
2522	*bmc_new = 2;
2523	md_bitmap_count_page(bitmap: &bitmap->counts, offset: block, inc: 1);
2524	md_bitmap_set_pending(bitmap: &bitmap->counts, offset: block);
2525	}
2526	*bmc_new |= NEEDED_MASK;
2527	}
2528	if (new_blocks < old_blocks)
2529	old_blocks = new_blocks;
2530	}
2531	block += old_blocks;
2532	}
2533
2534	if (bitmap->counts.bp != old_counts.bp) {
2535	unsigned long k;
2536	for (k = 0; k < old_counts.pages; k++)
2537	if (!old_counts.bp[k].hijacked)
2538	kfree(objp: old_counts.bp[k].map);
2539	kfree(objp: old_counts.bp);
2540	}
2541
2542	if (!init) {
2543	int i;
2544	while (block < (chunks << chunkshift)) {
2545	bitmap_counter_t *bmc;
2546	bmc = md_bitmap_get_counter(bitmap: &bitmap->counts, offset: block, blocks: &new_blocks, create: 1);
2547	if (bmc) {
2548	/* new space. It needs to be resynced, so
2549	* we set NEEDED_MASK.
2550	*/
2551	if (*bmc == 0) {
2552	*bmc = NEEDED_MASK | 2;
2553	md_bitmap_count_page(bitmap: &bitmap->counts, offset: block, inc: 1);
2554	md_bitmap_set_pending(bitmap: &bitmap->counts, offset: block);
2555	}
2556	}
2557	block += new_blocks;
2558	}
2559	for (i = 0; i < bitmap->storage.file_pages; i++)
2560	set_page_attr(bitmap, pnum: i, attr: BITMAP_PAGE_DIRTY);
2561	}
2562	spin_unlock_irq(lock: &bitmap->counts.lock);
2563
2564	if (!init) {
2565	__bitmap_unplug(bitmap);
2566	bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
2567	}
2568	ret = 0;
2569	err:
2570	return ret;
2571	}
2572
2573	static int bitmap_resize(struct mddev *mddev, sector_t blocks, int chunksize)
2574	{
2575	struct bitmap *bitmap = mddev->bitmap;
2576
2577	if (!bitmap)
2578	return 0;
2579
2580	return __bitmap_resize(bitmap, blocks, chunksize, init: false);
2581	}
2582
2583	static ssize_t
2584	location_show(struct mddev *mddev, char *page)
2585	{
2586	ssize_t len;
2587	if (mddev->bitmap_info.file)
2588	len = sprintf(buf: page, fmt: "file");
2589	else if (mddev->bitmap_info.offset)
2590	len = sprintf(buf: page, fmt: "%+lld", (long long)mddev->bitmap_info.offset);
2591	else
2592	len = sprintf(buf: page, fmt: "none");
2593	len += sprintf(buf: page+len, fmt: "\n");
2594	return len;
2595	}
2596
2597	static ssize_t
2598	location_store(struct mddev *mddev, const char *buf, size_t len)
2599	{
2600	int rv;
2601
2602	rv = mddev_suspend_and_lock(mddev);
2603	if (rv)
2604	return rv;
2605
2606	if (mddev->pers) {
2607	if (mddev->recovery || mddev->sync_thread) {
2608	rv = -EBUSY;
2609	goto out;
2610	}
2611	}
2612
2613	if (mddev->bitmap || mddev->bitmap_info.file ||
2614	mddev->bitmap_info.offset) {
2615	/* bitmap already configured. Only option is to clear it */
2616	if (strncmp(buf, "none", 4) != 0) {
2617	rv = -EBUSY;
2618	goto out;
2619	}
2620
2621	bitmap_destroy(mddev);
2622	mddev->bitmap_info.offset = 0;
2623	if (mddev->bitmap_info.file) {
2624	struct file *f = mddev->bitmap_info.file;
2625	mddev->bitmap_info.file = NULL;
2626	fput(f);
2627	}
2628	} else {
2629	/* No bitmap, OK to set a location */
2630	long long offset;
2631
2632	if (strncmp(buf, "none", 4) == 0)
2633	/* nothing to be done */;
2634	else if (strncmp(buf, "file:", 5) == 0) {
2635	/* Not supported yet */
2636	rv = -EINVAL;
2637	goto out;
2638	} else {
2639	if (buf[0] == '+')
2640	rv = kstrtoll(s: buf+1, base: 10, res: &offset);
2641	else
2642	rv = kstrtoll(s: buf, base: 10, res: &offset);
2643	if (rv)
2644	goto out;
2645	if (offset == 0) {
2646	rv = -EINVAL;
2647	goto out;
2648	}
2649	if (mddev->bitmap_info.external == 0 &&
2650	mddev->major_version == 0 &&
2651	offset != mddev->bitmap_info.default_offset) {
2652	rv = -EINVAL;
2653	goto out;
2654	}
2655
2656	mddev->bitmap_info.offset = offset;
2657	rv = bitmap_create(mddev);
2658	if (rv)
2659	goto out;
2660
2661	rv = bitmap_load(mddev);
2662	if (rv) {
2663	mddev->bitmap_info.offset = 0;
2664	bitmap_destroy(mddev);
2665	goto out;
2666	}
2667	}
2668	}
2669	if (!mddev->external) {
2670	/* Ensure new bitmap info is stored in
2671	* metadata promptly.
2672	*/
2673	set_bit(nr: MD_SB_CHANGE_DEVS, addr: &mddev->sb_flags);
2674	md_wakeup_thread(mddev->thread);
2675	}
2676	rv = 0;
2677	out:
2678	mddev_unlock_and_resume(mddev);
2679	if (rv)
2680	return rv;
2681	return len;
2682	}
2683
2684	static struct md_sysfs_entry bitmap_location =
2685	__ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2686
2687	/* 'bitmap/space' is the space available at 'location' for the
2688	* bitmap. This allows the kernel to know when it is safe to
2689	* resize the bitmap to match a resized array.
2690	*/
2691	static ssize_t
2692	space_show(struct mddev *mddev, char *page)
2693	{
2694	return sprintf(buf: page, fmt: "%lu\n", mddev->bitmap_info.space);
2695	}
2696
2697	static ssize_t
2698	space_store(struct mddev *mddev, const char *buf, size_t len)
2699	{
2700	struct bitmap *bitmap;
2701	unsigned long sectors;
2702	int rv;
2703
2704	rv = kstrtoul(s: buf, base: 10, res: &sectors);
2705	if (rv)
2706	return rv;
2707
2708	if (sectors == 0)
2709	return -EINVAL;
2710
2711	bitmap = mddev->bitmap;
2712	if (bitmap && sectors < (bitmap->storage.bytes + 511) >> 9)
2713	return -EFBIG; /* Bitmap is too big for this small space */
2714
2715	/* could make sure it isn't too big, but that isn't really
2716	* needed - user-space should be careful.
2717	*/
2718	mddev->bitmap_info.space = sectors;
2719	return len;
2720	}
2721
2722	static struct md_sysfs_entry bitmap_space =
2723	__ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2724
2725	static ssize_t
2726	timeout_show(struct mddev *mddev, char *page)
2727	{
2728	ssize_t len;
2729	unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2730	unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2731
2732	len = sprintf(buf: page, fmt: "%lu", secs);
2733	if (jifs)
2734	len += sprintf(buf: page+len, fmt: ".%03u", jiffies_to_msecs(j: jifs));
2735	len += sprintf(buf: page+len, fmt: "\n");
2736	return len;
2737	}
2738
2739	static ssize_t
2740	timeout_store(struct mddev *mddev, const char *buf, size_t len)
2741	{
2742	/* timeout can be set at any time */
2743	unsigned long timeout;
2744	int rv = strict_strtoul_scaled(cp: buf, res: &timeout, scale: 4);
2745	if (rv)
2746	return rv;
2747
2748	/* just to make sure we don't overflow... */
2749	if (timeout >= LONG_MAX / HZ)
2750	return -EINVAL;
2751
2752	timeout = timeout * HZ / 10000;
2753
2754	if (timeout >= MAX_SCHEDULE_TIMEOUT)
2755	timeout = MAX_SCHEDULE_TIMEOUT-1;
2756	if (timeout < 1)
2757	timeout = 1;
2758
2759	mddev->bitmap_info.daemon_sleep = timeout;
2760	mddev_set_timeout(mddev, timeout, force: false);
2761	md_wakeup_thread(mddev->thread);
2762
2763	return len;
2764	}
2765
2766	static struct md_sysfs_entry bitmap_timeout =
2767	__ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2768
2769	static ssize_t
2770	backlog_show(struct mddev *mddev, char *page)
2771	{
2772	return sprintf(buf: page, fmt: "%lu\n", mddev->bitmap_info.max_write_behind);
2773	}
2774
2775	static ssize_t
2776	backlog_store(struct mddev *mddev, const char *buf, size_t len)
2777	{
2778	unsigned long backlog;
2779	unsigned long old_mwb = mddev->bitmap_info.max_write_behind;
2780	struct md_rdev *rdev;
2781	bool has_write_mostly = false;
2782	int rv = kstrtoul(s: buf, base: 10, res: &backlog);
2783	if (rv)
2784	return rv;
2785	if (backlog > COUNTER_MAX)
2786	return -EINVAL;
2787
2788	rv = mddev_suspend_and_lock(mddev);
2789	if (rv)
2790	return rv;
2791
2792	/*
2793	* Without write mostly device, it doesn't make sense to set
2794	* backlog for max_write_behind.
2795	*/
2796	rdev_for_each(rdev, mddev) {
2797	if (test_bit(WriteMostly, &rdev->flags)) {
2798	has_write_mostly = true;
2799	break;
2800	}
2801	}
2802	if (!has_write_mostly) {
2803	pr_warn_ratelimited("%s: can't set backlog, no write mostly device available\n",
2804	mdname(mddev));
2805	mddev_unlock(mddev);
2806	return -EINVAL;
2807	}
2808
2809	mddev->bitmap_info.max_write_behind = backlog;
2810	if (!backlog && mddev->serial_info_pool) {
2811	/* serial_info_pool is not needed if backlog is zero */
2812	if (!mddev->serialize_policy)
2813	mddev_destroy_serial_pool(mddev, NULL);
2814	} else if (backlog && !mddev->serial_info_pool) {
2815	/* serial_info_pool is needed since backlog is not zero */
2816	rdev_for_each(rdev, mddev)
2817	mddev_create_serial_pool(mddev, rdev);
2818	}
2819	if (old_mwb != backlog)
2820	bitmap_update_sb(data: mddev->bitmap);
2821
2822	mddev_unlock_and_resume(mddev);
2823	return len;
2824	}
2825
2826	static struct md_sysfs_entry bitmap_backlog =
2827	__ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2828
2829	static ssize_t
2830	chunksize_show(struct mddev *mddev, char *page)
2831	{
2832	return sprintf(buf: page, fmt: "%lu\n", mddev->bitmap_info.chunksize);
2833	}
2834
2835	static ssize_t
2836	chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2837	{
2838	/* Can only be changed when no bitmap is active */
2839	int rv;
2840	unsigned long csize;
2841	if (mddev->bitmap)
2842	return -EBUSY;
2843	rv = kstrtoul(s: buf, base: 10, res: &csize);
2844	if (rv)
2845	return rv;
2846	if (csize < 512 ||
2847	!is_power_of_2(n: csize))
2848	return -EINVAL;
2849	if (BITS_PER_LONG > 32 && csize >= (1ULL << (BITS_PER_BYTE *
2850	sizeof(((bitmap_super_t *)0)->chunksize))))
2851	return -EOVERFLOW;
2852	mddev->bitmap_info.chunksize = csize;
2853	return len;
2854	}
2855
2856	static struct md_sysfs_entry bitmap_chunksize =
2857	__ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2858
2859	static ssize_t metadata_show(struct mddev *mddev, char *page)
2860	{
2861	if (mddev_is_clustered(mddev))
2862	return sprintf(buf: page, fmt: "clustered\n");
2863	return sprintf(buf: page, fmt: "%s\n", (mddev->bitmap_info.external
2864	? "external" : "internal"));
2865	}
2866
2867	static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2868	{
2869	if (mddev->bitmap ||
2870	mddev->bitmap_info.file ||
2871	mddev->bitmap_info.offset)
2872	return -EBUSY;
2873	if (strncmp(buf, "external", 8) == 0)
2874	mddev->bitmap_info.external = 1;
2875	else if ((strncmp(buf, "internal", 8) == 0) ||
2876	(strncmp(buf, "clustered", 9) == 0))
2877	mddev->bitmap_info.external = 0;
2878	else
2879	return -EINVAL;
2880	return len;
2881	}
2882
2883	static struct md_sysfs_entry bitmap_metadata =
2884	__ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2885
2886	static ssize_t can_clear_show(struct mddev *mddev, char *page)
2887	{
2888	int len;
2889	struct bitmap *bitmap;
2890
2891	spin_lock(lock: &mddev->lock);
2892	bitmap = mddev->bitmap;
2893	if (bitmap)
2894	len = sprintf(buf: page, fmt: "%s\n", (bitmap->need_sync ? "false" :
2895	"true"));
2896	else
2897	len = sprintf(buf: page, fmt: "\n");
2898	spin_unlock(lock: &mddev->lock);
2899	return len;
2900	}
2901
2902	static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2903	{
2904	struct bitmap *bitmap = mddev->bitmap;
2905
2906	if (!bitmap)
2907	return -ENOENT;
2908
2909	if (strncmp(buf, "false", 5) == 0) {
2910	bitmap->need_sync = 1;
2911	return len;
2912	}
2913
2914	if (strncmp(buf, "true", 4) == 0) {
2915	if (mddev->degraded)
2916	return -EBUSY;
2917	bitmap->need_sync = 0;
2918	return len;
2919	}
2920
2921	return -EINVAL;
2922	}
2923
2924	static struct md_sysfs_entry bitmap_can_clear =
2925	__ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2926
2927	static ssize_t
2928	behind_writes_used_show(struct mddev *mddev, char *page)
2929	{
2930	ssize_t ret;
2931	struct bitmap *bitmap;
2932
2933	spin_lock(lock: &mddev->lock);
2934	bitmap = mddev->bitmap;
2935	if (!bitmap)
2936	ret = sprintf(buf: page, fmt: "0\n");
2937	else
2938	ret = sprintf(buf: page, fmt: "%lu\n", bitmap->behind_writes_used);
2939	spin_unlock(lock: &mddev->lock);
2940
2941	return ret;
2942	}
2943
2944	static ssize_t
2945	behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2946	{
2947	struct bitmap *bitmap = mddev->bitmap;
2948
2949	if (bitmap)
2950	bitmap->behind_writes_used = 0;
2951	return len;
2952	}
2953
2954	static struct md_sysfs_entry max_backlog_used =
2955	__ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2956	behind_writes_used_show, behind_writes_used_reset);
2957
2958	static struct attribute *md_bitmap_attrs[] = {
2959	&bitmap_location.attr,
2960	&bitmap_space.attr,
2961	&bitmap_timeout.attr,
2962	&bitmap_backlog.attr,
2963	&bitmap_chunksize.attr,
2964	&bitmap_metadata.attr,
2965	&bitmap_can_clear.attr,
2966	&max_backlog_used.attr,
2967	NULL
2968	};
2969
2970	static struct attribute_group md_bitmap_group = {
2971	.name = "bitmap",
2972	.attrs = md_bitmap_attrs,
2973	};
2974
2975	static struct bitmap_operations bitmap_ops = {
2976	.head = {
2977	.type = MD_BITMAP,
2978	.id = ID_BITMAP,
2979	.name = "bitmap",
2980	},
2981
2982	.enabled = bitmap_enabled,
2983	.create = bitmap_create,
2984	.resize = bitmap_resize,
2985	.load = bitmap_load,
2986	.destroy = bitmap_destroy,
2987	.flush = bitmap_flush,
2988	.write_all = bitmap_write_all,
2989	.dirty_bits = bitmap_dirty_bits,
2990	.unplug = bitmap_unplug,
2991	.daemon_work = bitmap_daemon_work,
2992
2993	.start_behind_write = bitmap_start_behind_write,
2994	.end_behind_write = bitmap_end_behind_write,
2995	.wait_behind_writes = bitmap_wait_behind_writes,
2996
2997	.start_write = bitmap_start_write,
2998	.end_write = bitmap_end_write,
2999	.start_discard = bitmap_start_write,
3000	.end_discard = bitmap_end_write,
3001
3002	.start_sync = bitmap_start_sync,
3003	.end_sync = bitmap_end_sync,
3004	.cond_end_sync = bitmap_cond_end_sync,
3005	.close_sync = bitmap_close_sync,
3006
3007	.update_sb = bitmap_update_sb,
3008	.get_stats = bitmap_get_stats,
3009
3010	.sync_with_cluster = bitmap_sync_with_cluster,
3011	.get_from_slot = bitmap_get_from_slot,
3012	.copy_from_slot = bitmap_copy_from_slot,
3013	.set_pages = bitmap_set_pages,
3014	.free = md_bitmap_free,
3015
3016	.group = &md_bitmap_group,
3017	};
3018
3019	int md_bitmap_init(void)
3020	{
3021	md_bitmap_wq = alloc_workqueue("md_bitmap", WQ_MEM_RECLAIM | WQ_UNBOUND,
3022	0);
3023	if (!md_bitmap_wq)
3024	return -ENOMEM;
3025
3026	return register_md_submodule(msh: &bitmap_ops.head);
3027	}
3028
3029	void md_bitmap_exit(void)
3030	{
3031	destroy_workqueue(wq: md_bitmap_wq);
3032	unregister_md_submodule(msh: &bitmap_ops.head);
3033	}
3034