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

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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: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2010-06-01 19:37:34 +10:00
parent ef42567335
commit e384e58549
3 changed files with 99 additions and 39 deletions
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128
drivers/md/bitmap.c
View File

@ -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)
{
__set_bit((page->index<<2) + attr, bitmap->filemap_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)
{
__clear_bit((page->index<<2) + attr, bitmap->filemap_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)
{
return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
if (page)
return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
else
return test_bit(attr, &bitmap->logattrs);
}
/*
@ -818,27 +830,30 @@ 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)
return;
bit = file_page_offset(bitmap, chunk);
/* set the bit */
kaddr = kmap_atomic(page, KM_USER0);
if (bitmap->flags & BITMAP_HOSTENDIAN)
set_bit(bit, kaddr);
else
ext2_set_bit(bit, kaddr);
kunmap_atomic(kaddr, KM_USER0);
PRINTK("set file bit %lu page %lu\n", bit, page->index);
page = filemap_get_page(bitmap, chunk);
if (!page)
return;
bit = file_page_offset(bitmap, chunk);
/* set the bit */
kaddr = kmap_atomic(page, KM_USER0);
if (bitmap->flags & BITMAP_HOSTENDIAN)
set_bit(bit, kaddr);
else
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.
@ -1114,11 +1141,12 @@ 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)
/* error or shutdown */
break;
page = filemap_get_page(bitmap, j);
if (!bitmap->filemap) {
if (!log)
/* error or shutdown */
break;
} else
page = filemap_get_page(bitmap, j);
if (page != lastpage) {
/* skip this page unless it's marked as needing cleaning */
@ -1187,14 +1215,17 @@ void bitmap_daemon_work(mddev_t *mddev)
-1);
/* clear the bit */
paddr = kmap_atomic(page, KM_USER0);
if (bitmap->flags & BITMAP_HOSTENDIAN)
clear_bit(file_page_offset(bitmap, j),
paddr);
else
ext2_clear_bit(file_page_offset(bitmap, j),
paddr);
kunmap_atomic(paddr, KM_USER0);
if (page) {
paddr = kmap_atomic(page, KM_USER0);
if (bitmap->flags & BITMAP_HOSTENDIAN)
clear_bit(file_page_offset(bitmap, j),
paddr);
else
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);
write_page(bitmap, lastpage, 0);
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)
@ -1730,7 +1770,17 @@ 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;
err = bitmap_init_from_disk(bitmap, start);
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)
goto error;

5
drivers/md/bitmap.h
View File

@ -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 */

5
drivers/md/md.h
View File

@ -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? */