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Commit e384e585 authored by NeilBrown's avatar NeilBrown
Browse files

md/bitmap: prepare for storing write-intent-bitmap via dm-dirty-log. 



This allows md/raid5 to fully work as a dm target.

Normally md uses a 'filemap' which contains a list of pages of bits
each of which may be written separately.
dm-log uses and all-or-nothing approach to writing the log, so
when using a dm-log, ->filemap is NULL and the flags normally stored
in filemap_attr are stored in ->logattrs instead.



Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent ef425673

drivers/md/bitmap.c

+89 −39
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include "md.h"

#include "bitmap.h"



#include <linux/dm-dirty-log.h>

/* debug macros */



#define DEBUG 0
@@ -694,6 +695,8 @@ static inline unsigned long file_page_offset(struct bitmap *bitmap, unsigned lon 
static inline struct page *filemap_get_page(struct bitmap *bitmap,

					unsigned long chunk)

{

	if (bitmap->filemap == NULL)

		return NULL;

	if (file_page_index(bitmap, chunk) >= bitmap->file_pages)

		return NULL;

	return bitmap->filemap[file_page_index(bitmap, chunk)
@@ -793,19 +796,28 @@ enum bitmap_page_attr { 
static inline void set_page_attr(struct bitmap *bitmap, struct page *page,

				enum bitmap_page_attr attr)

{

	if (page)

		__set_bit((page->index<<2) + attr, bitmap->filemap_attr);

	else

		__set_bit(attr, &bitmap->logattrs);

}



static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,

				enum bitmap_page_attr attr)

{

	if (page)

		__clear_bit((page->index<<2) + attr, bitmap->filemap_attr);

	else

		__clear_bit(attr, &bitmap->logattrs);

}



static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,

					   enum bitmap_page_attr attr)

{

	if (page)

		return test_bit((page->index<<2) + attr, bitmap->filemap_attr);

	else

		return test_bit(attr, &bitmap->logattrs);

}



/*
@@ -818,12 +830,15 @@ static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *p 
static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)

{

	unsigned long bit;

	struct page *page;

	struct page *page = NULL;

	void *kaddr;

	unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);



	if (!bitmap->filemap)

		return;

	if (!bitmap->filemap) {

		struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;

		if (log)

			log->type->mark_region(log, chunk);

	} else {



		page = filemap_get_page(bitmap, chunk);

		if (!page)
@@ -838,7 +853,7 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block) 
			ext2_set_bit(bit, kaddr);

		kunmap_atomic(kaddr, KM_USER0);

		PRINTK("set file bit %lu page %lu\n", bit, page->index);



	}

	/* record page number so it gets flushed to disk when unplug occurs */

	set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);

}
@@ -855,6 +870,16 @@ void bitmap_unplug(struct bitmap *bitmap) 


	if (!bitmap)

		return;

	if (!bitmap->filemap) {

		/* Must be using a dirty_log */

		struct dm_dirty_log *log = bitmap->mddev->bitmap_info.log;

		dirty = test_and_clear_bit(BITMAP_PAGE_DIRTY, &bitmap->logattrs);

		need_write = test_and_clear_bit(BITMAP_PAGE_NEEDWRITE, &bitmap->logattrs);

		if (dirty || need_write)

			if (log->type->flush(log))

				bitmap->flags |= BITMAP_WRITE_ERROR;

		goto out;

	}



	/* look at each page to see if there are any set bits that need to be

	 * flushed out to disk */
@@ -883,6 +908,7 @@ void bitmap_unplug(struct bitmap *bitmap) 
		else

			md_super_wait(bitmap->mddev);

	}

out:

	if (bitmap->flags & BITMAP_WRITE_ERROR)

		bitmap_file_kick(bitmap);

}
@@ -925,11 +951,11 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start) 
		printk(KERN_INFO "%s: bitmap file is out of date, doing full "

			"recovery\n", bmname(bitmap));



	bytes = (chunks + 7) / 8;

	bytes = DIV_ROUND_UP(bitmap->chunks, 8);

	if (!bitmap->mddev->bitmap_info.external)

		bytes += sizeof(bitmap_super_t);



	num_pages = (bytes + PAGE_SIZE - 1) / PAGE_SIZE;

	num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);



	if (file && i_size_read(file->f_mapping->host) < bytes) {

		printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
@@ -1090,6 +1116,7 @@ void bitmap_daemon_work(mddev_t *mddev) 
	struct page *page = NULL, *lastpage = NULL;

	int blocks;

	void *paddr;

	struct dm_dirty_log *log = mddev->bitmap_info.log;



	/* Use a mutex to guard daemon_work against

	 * bitmap_destroy.
@@ -1114,10 +1141,11 @@ void bitmap_daemon_work(mddev_t *mddev) 
	spin_lock_irqsave(&bitmap->lock, flags);

	for (j = 0; j < bitmap->chunks; j++) {

		bitmap_counter_t *bmc;

		if (!bitmap->filemap)

		if (!bitmap->filemap) {

			if (!log)

				/* error or shutdown */

				break;



		} else

			page = filemap_get_page(bitmap, j);



		if (page != lastpage) {
@@ -1187,6 +1215,7 @@ void bitmap_daemon_work(mddev_t *mddev) 
						  -1);



				/* clear the bit */

				if (page) {

					paddr = kmap_atomic(page, KM_USER0);

					if (bitmap->flags & BITMAP_HOSTENDIAN)

						clear_bit(file_page_offset(bitmap, j),
@@ -1195,6 +1224,8 @@ void bitmap_daemon_work(mddev_t *mddev) 
						ext2_clear_bit(file_page_offset(bitmap, j),

							       paddr);

					kunmap_atomic(paddr, KM_USER0);

				} else

					log->type->clear_region(log, j);

			}

		} else

			j |= PAGE_COUNTER_MASK;
@@ -1202,12 +1233,16 @@ void bitmap_daemon_work(mddev_t *mddev) 
	spin_unlock_irqrestore(&bitmap->lock, flags);



	/* now sync the final page */

	if (lastpage != NULL) {

	if (lastpage != NULL || log != NULL) {

		spin_lock_irqsave(&bitmap->lock, flags);

		if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {

			clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);

			spin_unlock_irqrestore(&bitmap->lock, flags);

			if (lastpage)

				write_page(bitmap, lastpage, 0);

			else

				if (log->type->flush(log))

					bitmap->flags |= BITMAP_WRITE_ERROR;

		} else {

			set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);

			spin_unlock_irqrestore(&bitmap->lock, flags);
@@ -1372,7 +1407,9 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto 
		(*bmc)--;

		if (*bmc <= 2)

			set_page_attr(bitmap,

				      filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),

				      filemap_get_page(

					      bitmap,

					      offset >> CHUNK_BLOCK_SHIFT(bitmap)),

				      BITMAP_PAGE_CLEAN);



		spin_unlock_irqrestore(&bitmap->lock, flags);
@@ -1649,10 +1686,13 @@ int bitmap_create(mddev_t *mddev) 


	BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);



	if (!file && !mddev->bitmap_info.offset) /* bitmap disabled, nothing to do */

	if (!file

	    && !mddev->bitmap_info.offset

	    && !mddev->bitmap_info.log) /* bitmap disabled, nothing to do */

		return 0;



	BUG_ON(file && mddev->bitmap_info.offset);

	BUG_ON(mddev->bitmap_info.offset && mddev->bitmap_info.log);



	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);

	if (!bitmap)
@@ -1730,6 +1770,16 @@ int bitmap_create(mddev_t *mddev) 
	    || bitmap->events_cleared == mddev->events)

		/* no need to keep dirty bits to optimise a re-add of a missing device */

		start = mddev->recovery_cp;

	if (mddev->bitmap_info.log) {

		unsigned long i;

		struct dm_dirty_log *log = mddev->bitmap_info.log;

		for (i = 0; i < bitmap->chunks; i++)

			if (!log->type->in_sync(log, i, 1))

				bitmap_set_memory_bits(bitmap,

						       (sector_t)i << CHUNK_BLOCK_SHIFT(bitmap),

						       1);

		err = 0;

	} else

		err = bitmap_init_from_disk(bitmap, start);



	if (err)

drivers/md/bitmap.h

+5 −0
Original line number Diff line number Diff line
@@ -222,6 +222,10 @@ struct bitmap { 
	unsigned long file_pages; /* number of pages in the file */

	int last_page_size; /* bytes in the last page */



	unsigned long logattrs; /* used when filemap_attr doesn't exist

				 * because we are working with a dirty_log

				 */



	unsigned long flags;



	int allclean;
@@ -243,6 +247,7 @@ struct bitmap { 
	wait_queue_head_t behind_wait;



	struct sysfs_dirent *sysfs_can_clear;



};



/* the bitmap API */

drivers/md/md.h

+5 −0
Original line number Diff line number Diff line
@@ -317,6 +317,11 @@ struct mddev_s 
							 * hot-adding a bitmap.  It should

							 * eventually be settable by sysfs.

							 */

		/* When md is serving under dm, it might use a

		 * dirty_log to store the bits.

		 */

		struct dm_dirty_log *log;



		struct mutex		mutex;

		unsigned long		chunksize;

		unsigned long		daemon_sleep; /* how many jiffies between updates? */