/*
drbd_bitmap.c
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2004-2008, LINBIT Information Technologies GmbH.
Copyright (C) 2004-2008, Philipp Reisner <philipp.reisner@linbit.com>.
Copyright (C) 2004-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
drbd is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
drbd is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with drbd; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/bitops.h>
#include <linux/vmalloc.h>
#include <linux/string.h>
#include <linux/drbd.h>
#include <linux/slab.h>
#include <asm/kmap_types.h>
#include "drbd_int.h"
/* OPAQUE outside this file!
* interface defined in drbd_int.h
* convention:
* function name drbd_bm_... => used elsewhere, "public".
* function name bm_... => internal to implementation, "private".
* Note that since find_first_bit returns int, at the current granularity of
* the bitmap (4KB per byte), this implementation "only" supports up to
* 1<<(32+12) == 16 TB...
*/
/*
* NOTE
* Access to the *bm_pages is protected by bm_lock.
* It is safe to read the other members within the lock.
*
* drbd_bm_set_bits is called from bio_endio callbacks,
* We may be called with irq already disabled,
* so we need spin_lock_irqsave().
* And we need the kmap_atomic.
*/
struct drbd_bitmap {
struct page **bm_pages;
spinlock_t bm_lock;
/* WARNING unsigned long bm_*:
* 32bit number of bit offset is just enough for 512 MB bitmap.
* it will blow up if we make the bitmap bigger...
* not that it makes much sense to have a bitmap that large,
* rather change the granularity to 16k or 64k or something.
* (that implies other problems, however...)
*/
unsigned long bm_set; /* nr of set bits; THINK maybe atomic_t? */
unsigned long bm_bits;
size_t bm_words;
size_t bm_number_of_pages;
sector_t bm_dev_capacity;
struct mutex bm_change; /* serializes resize operations */
atomic_t bm_async_io;
wait_queue_head_t bm_io_wait;
unsigned long bm_flags;
/* debugging aid, in case we are still racy somewhere */
char *bm_why;
struct task_struct *bm_task;
};
/* definition of bits in bm_flags */
#define BM_LOCKED 0
#define BM_MD_IO_ERROR 1
#define BM_P_VMALLOCED 2
static int __bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
unsigned long e, int val, const enum km_type km);
static int bm_is_locked(struct drbd_bitmap *b)
{
return test_bit(BM_LOCKED, &b->bm_flags);
}
#define bm_print_lock_info(m) __bm_print_lock_info(m, __func__)
static void __bm_print_lock_info(struct drbd_conf *mdev, const char *func)
{
struct drbd_bitmap *b = mdev->bitmap;
if (!__ratelimit(&drbd_ratelimit_state))
return;
dev_err(DEV, "FIXME %s in %s, bitmap locked for '%s' by %s\n",
current == mdev->receiver.task ? "receiver" :
current == mdev->asender.task ? "asender" :
current == mdev->worker.task ? "worker" : current->comm,
func, b->bm_why ?: "?",
b->bm_task == mdev->receiver.task ? "receiver" :
b->bm_task == mdev->asender.task ? "asender" :
b->bm_task == mdev->worker.task ? "worker" : "?");
}
void drbd_bm_lock(struct drbd_conf *mdev, char *why)
{
struct drbd_bitmap *b = mdev->bitmap;
int trylock_failed;
if (!b) {
dev_err(DEV, "FIXME no bitmap in drbd_bm_lock!?\n");
return;
}
trylock_failed = !mutex_trylock(&b->bm_change);
if (trylock_failed) {
dev_warn(DEV, "%s going to '%s' but bitmap already locked for '%s' by %s\n",
current == mdev->receiver.task ? "receiver" :
current == mdev->asender.task ? "asender" :
current == mdev->worker.task ? "worker" : current->comm,
why, b->bm_why ?: "?",
b->bm_task == mdev->receiver.task ? "receiver" :
b->bm_task == mdev->asender.task ? "asender" :
b->bm_task == mdev->worker.task ? "worker" : "?");
mutex_lock(&b->bm_change);
}
if (__test_and_set_bit(BM_LOCKED, &b->bm_flags))
dev_err(DEV, "FIXME bitmap already locked in bm_lock\n");
b->bm_why = why;
b->bm_task = current;
}
void drbd_bm_unlock(struct drbd_conf *mdev)
{
struct drbd_bitmap *b = mdev->bitmap;
if (!b) {
dev_err(DEV, "FIXME no bitmap in drbd_bm_unlock!?\n");
return;
}
if (!__test_and_clear_bit(BM_LOCKED, &mdev->bitmap->bm_flags))
dev_err(DEV, "FIXME bitmap not locked in bm_unlock\n");
b->bm_why = NULL;
b->bm_task = NULL;
mutex_unlock(&b->bm_change);
}
/* word offset to long pointer */
static unsigned long *__bm_map_paddr(struct drbd_bitmap *b, unsigned long offset, const enum km_type km)
{
struct page *page;
unsigned long page_nr;
/* page_nr = (word*sizeof(long)) >> PAGE_SHIFT; */
page_nr = offset >> (PAGE_SHIFT - LN2_BPL + 3);
BUG_ON(page_nr >= b->bm_number_of_pages);
page = b->bm_pages[page_nr];
return (unsigned long *) kmap_atomic(page, km);
}
static unsigned long * bm_map_paddr(struct drbd_bitmap *b, unsigned long offset)
{
return __bm_map_paddr(b, offset, KM_IRQ1);
}
static void __bm_unmap(unsigned long *p_addr, const enum km_type km)
{
kunmap_atomic(p_addr, km);
};
static void bm_unmap(unsigned long *p_addr)
{
return __bm_unmap(p_addr, KM_IRQ1);
}
/* long word offset of _bitmap_ sector */
#define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL))
/* word offset from start of bitmap to word number _in_page_
* modulo longs per page
#define MLPP(X) ((X) % (PAGE_SIZE/sizeof(long))
hm, well, Philipp thinks gcc might not optimze the % into & (... - 1)
so do it explicitly:
*/
#define MLPP(X) ((X) & ((PAGE_SIZE/sizeof(long))-1))
/* Long words per page */
#define LWPP (PAGE_SIZE/sizeof(long))
/*
* actually most functions herein should take a struct drbd_bitmap*, not a
* struct drbd_conf*, but for the debug macros I like to have the mdev around
* to be able to report device specific.
*/
static void bm_free_pages(struct page **pages, unsigned long number)
{
unsigned long i;
if (!pages)
return;
for (i = 0; i < number; i++) {
if (!pages[i]) {
printk(KERN_ALERT "drbd: bm_free_pages tried to free "
"a NULL pointer; i=%lu n=%lu\n",
i, number);
continue;
}
__free_page(pages[i]);
pages[i] = NULL;
}
}
static void bm_vk_free(void *ptr, int v)
{
if (v)
vfree(ptr);
else
kfree(ptr);
}
/*
* "have" and "want" are NUMBER OF PAGES.
*/
static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want)
{
struct page **old_pages = b->bm_pages;
struct page **new_pages, *page;
unsigned int i, bytes, vmalloced = 0;
unsigned long have = b->bm_number_of_pages;
BUG_ON(have == 0 && old_pages != NULL);
BUG_ON(have != 0 && old_pages == NULL);
if (have == want)
return old_pages;
/* Trying kmalloc first, falling back to vmalloc.
* GFP_KERNEL is ok, as this is done when a lower level disk is
* "attached" to the drbd. Context is receiver thread or cqueue
* thread. As we have no disk yet, we are not in the IO path,
* not even the IO path of the peer. */
bytes = sizeof(struct page *)*want;
new_pages = kmalloc(bytes, GFP_KERNEL);
if (!new_pages) {
new_pages = vmalloc(bytes);
if (!new_pages)
return NULL;
vmalloced = 1;
}
memset(new_pages, 0, bytes);
if (want >= have) {
for (i = 0; i < have; i++)
new_pages[i] = old_pages[i];
for (; i < want; i++) {
page = alloc_page(GFP_HIGHUSER);
if (!page) {
bm_free_pages(new_pages + have, i - have);
bm_vk_free(new_pages, vmalloced);
return NULL;
}
new_pages[i] = page;
}
} else {
for (i = 0; i < want; i++)
new_pages[i] = old_pages[i];
/* NOT HERE, we are outside the spinlock!
bm_free_pages(old_pages + want, have - want);
*/
}
if (vmalloced)
set_bit(BM_P_VMALLOCED, &b->bm_flags);
else
clear_bit(BM_P_VMALLOCED, &b->bm_flags);
return new_pages;
}
/*
* called on driver init only. TODO call when a device is created.
* allocates the drbd_bitmap, and stores it in mdev->bitmap.
*/
int drbd_bm_init(struct drbd_conf *mdev)
{
struct drbd_bitmap *b = mdev->bitmap;
WARN_ON(b != NULL);
b = kzalloc(sizeof(struct drbd_bitmap), GFP_KERNEL);
if (!b)
return -ENOMEM;
spin_lock_init(&b->bm_lock);
mutex_init(&b->bm_change);
init_waitqueue_head(&b->bm_io_wait);
mdev->bitmap = b;
return 0;
}
sector_t drbd_bm_capacity(struct drbd_conf *mdev)
{
ERR_IF(!mdev->bitmap) return 0;
return mdev->bitmap->bm_dev_capacity;
}
/* called on driver unload. TODO: call when a device is destroyed.
*/
void drbd_bm_cleanup(struct drbd_conf *mdev)
{
ERR_IF (!mdev->bitmap) return;
bm_free_pages(mdev->bitmap->bm_pages, mdev->bitmap->bm_number_of_pages);
bm_vk_free(mdev->bitmap->bm_pages, test_bit(BM_P_VMALLOCED, &mdev->bitmap->bm_flags));
kfree(mdev->bitmap);
mdev->bitmap = NULL;
}
/*
* since (b->bm_bits % BITS_PER_LONG) != 0,
* this masks out the remaining bits.
* Returns the number of bits cleared.
*/
static int bm_clear_surplus(struct drbd_bitmap *b)
{
const unsigned long mask = (1UL << (b->bm_bits & (BITS_PER_LONG-1))) - 1;
size_t w = b->bm_bits >> LN2_BPL;
int cleared = 0;
unsigned long *p_addr, *bm;
p_addr = bm_map_paddr(b, w);
bm = p_addr + MLPP(w);
if (w < b->bm_words) {
cleared = hweight_long(*bm & ~mask);
*bm &= mask;
w++; bm++;
}
if (w < b->bm_words) {
cleared += hweight_long(*bm);
*bm = 0;
}
bm_unmap(p_addr);
return cleared;
}
static void bm_set_surplus(struct drbd_bitmap *b)
{
const unsigned long mask = (1UL << (b->bm_bits & (BITS_PER_LONG-1))) - 1;
size_t w = b->bm_bits >> LN2_BPL;
unsigned long *p_addr, *bm;
p_addr = bm_map_paddr(b, w);
bm = p_addr + MLPP(w);
if (w < b->bm_words) {
*bm |= ~mask;
bm++; w++;
}
if (w < b->bm_words) {
*bm = ~(0UL);
}
bm_unmap(p_addr);
}
static unsigned long __bm_count_bits(struct drbd_bitmap *b, const int swap_endian)
{
unsigned long *p_addr, *bm, offset = 0;
unsigned long bits = 0;
unsigned long i, do_now;
while (offset < b->bm_words) {
i = do_now = min_t(size_t, b->bm_words-offset, LWPP);
p_addr = __bm_map_paddr(b, offset, KM_USER0);
bm = p_addr + MLPP(offset);
while (i--) {
#ifndef __LITTLE_ENDIAN
if (swap_endian)
*bm = lel_to_cpu(*bm);
#endif
bits += hweight_long(*bm++);
}
__bm_unmap(p_addr, KM_USER0);
offset += do_now;
cond_resched();
}
return bits;
}
static unsigned long bm_count_bits(struct drbd_bitmap *b)
{
return __bm_count_bits(b, 0);
}
static unsigned long bm_count_bits_swap_endian(struct drbd_bitmap *b)
{
return __bm_count_bits(b, 1);
}
/* offset and len in long words.*/
static void bm_memset(struct drbd_bitmap *b, size_t offset, int c, size_t len)
{
unsigned long *p_addr, *bm;
size_t do_now, end;
#define BM_SECTORS_PER_BIT (BM_BLOCK_SIZE/512)
end = offset + len;
if (end > b->bm_words) {
printk(KERN_ALERT "drbd: bm_memset end > bm_words\n");
return;
}
while (offset < end) {
do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset;
p_addr = bm_map_paddr(b, offset);
bm = p_addr + MLPP(offset);
if (bm+do_now > p_addr + LWPP) {
printk(KERN_ALERT "drbd: BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n",
p_addr, bm, (int)do_now);
break; /* breaks to after catch_oob_access_end() only! */
}
memset(bm, c, do_now * sizeof(long));
bm_unmap(p_addr);
offset += do_now;
}
}
/*
* make sure the bitmap has enough room for the attached storage,
* if necessary, resize.
* called whenever we may have changed the device size.
* returns -ENOMEM if we could not allocate enough memory, 0 on success.
* In case this is actually a resize, we copy the old bitmap into the new one.
* Otherwise, the bitmap is initialized to all bits set.
*/
int drbd_bm_resize(struct drbd_conf *mdev, sector_t capacity, int set_new_bits)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long bits, words, owords, obits, *p_addr, *bm;
unsigned long want, have, onpages; /* number of pages */
struct page **npages, **opages = NULL;
int err = 0, growing;
int opages_vmalloced;
ERR_IF(!b) return -ENOMEM;
drbd_bm_lock(mdev, "resize");
dev_info(DEV, "drbd_bm_resize called with capacity == %llu\n",
(unsigned long long)capacity);
if (capacity == b->bm_dev_capacity)
goto out;
opages_vmalloced = test_bit(BM_P_VMALLOCED, &b->bm_flags);
if (capacity == 0) {
spin_lock_irq(&b->bm_lock);
opages = b->bm_pages;
onpages = b->bm_number_of_pages;
owords = b->bm_words;
b->bm_pages = NULL;
b->bm_number_of_pages =
b->bm_set =
b->bm_bits =
b->bm_words =
b->bm_dev_capacity = 0;
spin_unlock_irq(&b->bm_lock);
bm_free_pages(opages, onpages);
bm_vk_free(opages, opages_vmalloced);
goto out;
}
bits = BM_SECT_TO_BIT(ALIGN(capacity, BM_SECT_PER_BIT));
/* if we would use
words = ALIGN(bits,BITS_PER_LONG) >> LN2_BPL;
a 32bit host could present the wrong number of words
to a 64bit host.
*/
words = ALIGN(bits, 64) >> LN2_BPL;
if (get_ldev(mdev)) {
D_ASSERT((u64)bits <= (((u64)mdev->ldev->md.md_size_sect-MD_BM_OFFSET) << 12));
put_ldev(mdev);
}
/* one extra long to catch off by one errors */
want = ALIGN((words+1)*sizeof(long), PAGE_SIZE) >> PAGE_SHIFT;
have = b->bm_number_of_pages;
if (want == have) {
D_ASSERT(b->bm_pages != NULL);
npages = b->bm_pages;
} else {
if (FAULT_ACTIVE(mdev, DRBD_FAULT_BM_ALLOC))
npages = NULL;
else
npages = bm_realloc_pages(b, want);
}
if (!npages) {
err = -ENOMEM;
goto out;
}
spin_lock_irq(&b->bm_lock);
opages = b->bm_pages;
owords = b->bm_words;
obits = b->bm_bits;
growing = bits > obits;
if (opages && growing && set_new_bits)
bm_set_surplus(b);
b->bm_pages = npages;
b->bm_number_of_pages = want;
b->bm_bits = bits;
b->bm_words = words;
b->bm_dev_capacity = capacity;
if (growing) {
if (set_new_bits) {
bm_memset(b, owords, 0xff, words-owords);
b->bm_set += bits - obits;
} else
bm_memset(b, owords, 0x00, words-owords);
}
if (want < have) {
/* implicit: (opages != NULL) && (opages != npages) */
bm_free_pages(opages + want, have - want);
}
p_addr = bm_map_paddr(b, words);
bm = p_addr + MLPP(words);
*bm = DRBD_MAGIC;
bm_unmap(p_addr);
(void)bm_clear_surplus(b);
spin_unlock_irq(&b->bm_lock);
if (opages != npages)
bm_vk_free(opages, opages_vmalloced);
if (!growing)
b->bm_set = bm_count_bits(b);
dev_info(DEV, "resync bitmap: bits=%lu words=%lu\n", bits, words);
out:
drbd_bm_unlock(mdev);
return err;
}
/* inherently racy:
* if not protected by other means, return value may be out of date when
* leaving this function...
* we still need to lock it, since it is important that this returns
* bm_set == 0 precisely.
*
* maybe bm_set should be atomic_t ?
*/
static unsigned long _drbd_bm_total_weight(struct drbd_conf *mdev)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long s;
unsigned long flags;
ERR_IF(!b) return 0;
ERR_IF(!b->bm_pages) return 0;
spin_lock_irqsave(&b->bm_lock, flags);
s = b->bm_set;
spin_unlock_irqrestore(&b->bm_lock, flags);
return s;
}
unsigned long drbd_bm_total_weight(struct drbd_conf *mdev)
{
unsigned long s;
/* if I don't have a disk, I don't know about out-of-sync status */
if (!get_ldev_if_state(mdev, D_NEGOTIATING))
return 0;
s = _drbd_bm_total_weight(mdev);
put_ldev(mdev);
return s;
}
size_t drbd_bm_words(struct drbd_conf *mdev)
{
struct drbd_bitmap *b = mdev->bitmap;
ERR_IF(!b) return 0;
ERR_IF(!b->bm_pages) return 0;
return b->bm_words;
}
unsigned long drbd_bm_bits(struct drbd_conf *mdev)
{
struct drbd_bitmap *b = mdev->bitmap;
ERR_IF(!b) return 0;
return b->bm_bits;
}
/* merge number words from buffer into the bitmap starting at offset.
* buffer[i] is expected to be little endian unsigned long.
* bitmap must be locked by drbd_bm_lock.
* currently only used from receive_bitmap.
*/
void drbd_bm_merge_lel(struct drbd_conf *mdev, size_t offset, size_t number,
unsigned long *buffer)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr, *bm;
unsigned long word, bits;
size_t end, do_now;
end = offset + number;
ERR_IF(!b) return;
ERR_IF(!b->bm_pages) return;
if (number == 0)
return;
WARN_ON(offset >= b->bm_words);
WARN_ON(end > b->bm_words);
spin_lock_irq(&b->bm_lock);
while (offset < end) {
do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
p_addr = bm_map_paddr(b, offset);
bm = p_addr + MLPP(offset);
offset += do_now;
while (do_now--) {
bits = hweight_long(*bm);
word = *bm | lel_to_cpu(*buffer++);
*bm++ = word;
b->bm_set += hweight_long(word) - bits;
}
bm_unmap(p_addr);
}
/* with 32bit <-> 64bit cross-platform connect
* this is only correct for current usage,
* where we _know_ that we are 64 bit aligned,
* and know that this function is used in this way, too...
*/
if (end == b->bm_words)
b->bm_set -= bm_clear_surplus(b);
spin_unlock_irq(&b->bm_lock);
}
/* copy number words from the bitmap starting at offset into the buffer.
* buffer[i] will be little endian unsigned long.
*/
void drbd_bm_get_lel(struct drbd_conf *mdev, size_t offset, size_t number,
unsigned long *buffer)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr, *bm;
size_t end, do_now;
end = offset + number;
ERR_IF(!b) return;
ERR_IF(!b->bm_pages) return;
spin_lock_irq(&b->bm_lock);
if ((offset >= b->bm_words) ||
(end > b->bm_words) ||
(number <= 0))
dev_err(DEV, "offset=%lu number=%lu bm_words=%lu\n",
(unsigned long) offset,
(unsigned long) number,
(unsigned long) b->bm_words);
else {
while (offset < end) {
do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
p_addr = bm_map_paddr(b, offset);
bm = p_addr + MLPP(offset);
offset += do_now;
while (do_now--)
*buffer++ = cpu_to_lel(*bm++);
bm_unmap(p_addr);
}
}
spin_unlock_irq(&b->bm_lock);
}
/* set all bits in the bitmap */
void drbd_bm_set_all(struct drbd_conf *mdev)
{
struct drbd_bitmap *b = mdev->bitmap;
ERR_IF(!b) return;
ERR_IF(!b->bm_pages) return;
spin_lock_irq(&b->bm_lock);
bm_memset(b, 0, 0xff, b->bm_words);
(void)bm_clear_surplus(b);
b->bm_set = b->bm_bits;
spin_unlock_irq(&b->bm_lock);
}
/* clear all bits in the bitmap */
void drbd_bm_clear_all(struct drbd_conf *mdev)
{
struct drbd_bitmap *b = mdev->bitmap;
ERR_IF(!b) return;
ERR_IF(!b->bm_pages) return;
spin_lock_irq(&b->bm_lock);
bm_memset(b, 0, 0, b->bm_words);
b->bm_set = 0;
spin_unlock_irq(&b->bm_lock);
}
static void bm_async_io_complete(struct bio *bio, int error)
{
struct drbd_bitmap *b = bio->bi_private;
int uptodate = bio_flagged(bio, BIO_UPTODATE);
/* strange behavior of some lower level drivers...
* fail the request by clearing the uptodate flag,
* but do not return any error?!
* do we want to WARN() on this? */
if (!error && !uptodate)
error = -EIO;
if (error) {
/* doh. what now?
* for now, set all bits, and flag MD_IO_ERROR */
__set_bit(BM_MD_IO_ERROR, &b->bm_flags);
}
if (atomic_dec_and_test(&b->bm_async_io))
wake_up(&b->bm_io_wait);
bio_put(bio);
}
static void bm_page_io_async(struct drbd_conf *mdev, struct drbd_bitmap *b, int page_nr, int rw) __must_hold(local)
{
/* we are process context. we always get a bio */
struct bio *bio = bio_alloc(GFP_KERNEL, 1);
unsigned int len;
sector_t on_disk_sector =
mdev->ldev->md.md_offset + mdev->ldev->md.bm_offset;
on_disk_sector += ((sector_t)page_nr) << (PAGE_SHIFT-9);
/* this might happen with very small
* flexible external meta data device */
len = min_t(unsigned int, PAGE_SIZE,
(drbd_md_last_sector(mdev->ldev) - on_disk_sector + 1)<<9);
bio->bi_bdev = mdev->ldev->md_bdev;
bio->bi_sector = on_disk_sector;
bio_add_page(bio, b->bm_pages[page_nr], len, 0);
bio->bi_private = b;
bio->bi_end_io = bm_async_io_complete;
if (FAULT_ACTIVE(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
bio->bi_rw |= rw;
bio_endio(bio, -EIO);
} else {
submit_bio(rw, bio);
}
}
# if defined(__LITTLE_ENDIAN)
/* nothing to do, on disk == in memory */
# define bm_cpu_to_lel(x) ((void)0)
# else
static void bm_cpu_to_lel(struct drbd_bitmap *b)
{
/* need to cpu_to_lel all the pages ...
* this may be optimized by using
* cpu_to_lel(-1) == -1 and cpu_to_lel(0) == 0;
* the following is still not optimal, but better than nothing */
unsigned int i;
unsigned long *p_addr, *bm;
if (b->bm_set == 0) {
/* no page at all; avoid swap if all is 0 */
i = b->bm_number_of_pages;
} else if (b->bm_set == b->bm_bits) {
/* only the last page */
i = b->bm_number_of_pages - 1;
} else {
/* all pages */
i = 0;
}
for (; i < b->bm_number_of_pages; i++) {
p_addr = kmap_atomic(b->bm_pages[i], KM_USER0);
for (bm = p_addr; bm < p_addr + PAGE_SIZE/sizeof(long); bm++)
*bm = cpu_to_lel(*bm);
kunmap_atomic(p_addr, KM_USER0);
}
}
# endif
/* lel_to_cpu == cpu_to_lel */
# define bm_lel_to_cpu(x) bm_cpu_to_lel(x)
/*
* bm_rw: read/write the whole bitmap from/to its on disk location.
*/
static int bm_rw(struct drbd_conf *mdev, int rw) __must_hold(local)
{
struct drbd_bitmap *b = mdev->bitmap;
/* sector_t sector; */
int bm_words, num_pages, i;
unsigned long now;
char ppb[10];
int err = 0;
WARN_ON(!bm_is_locked(b));
/* no spinlock here, the drbd_bm_lock should be enough! */
bm_words = drbd_bm_words(mdev);
num_pages = (bm_words*sizeof(long) + PAGE_SIZE-1) >> PAGE_SHIFT;
/* on disk bitmap is little endian */
if (rw == WRITE)
bm_cpu_to_lel(b);
now = jiffies;
atomic_set(&b->bm_async_io, num_pages);
__clear_bit(BM_MD_IO_ERROR, &b->bm_flags);
/* let the layers below us try to merge these bios... */
for (i = 0; i < num_pages; i++)
bm_page_io_async(mdev, b, i, rw);
drbd_blk_run_queue(bdev_get_queue(mdev->ldev->md_bdev));
wait_event(b->bm_io_wait, atomic_read(&b->bm_async_io) == 0);
if (test_bit(BM_MD_IO_ERROR, &b->bm_flags)) {
dev_alert(DEV, "we had at least one MD IO ERROR during bitmap IO\n");
drbd_chk_io_error(mdev, 1, TRUE);
err = -EIO;
}
now = jiffies;
if (rw == WRITE) {
/* swap back endianness */
bm_lel_to_cpu(b);
/* flush bitmap to stable storage */
drbd_md_flush(mdev);
} else /* rw == READ */ {
/* just read, if necessary adjust endianness */
b->bm_set = bm_count_bits_swap_endian(b);
dev_info(DEV, "recounting of set bits took additional %lu jiffies\n",
jiffies - now);
}
now = b->bm_set;
dev_info(DEV, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n",
ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now);
return err;
}
/**
* drbd_bm_read() - Read the whole bitmap from its on disk location.
* @mdev: DRBD device.
*/
int drbd_bm_read(struct drbd_conf *mdev) __must_hold(local)
{
return bm_rw(mdev, READ);
}
/**
* drbd_bm_write() - Write the whole bitmap to its on disk location.
* @mdev: DRBD device.
*/
int drbd_bm_write(struct drbd_conf *mdev) __must_hold(local)
{
return bm_rw(mdev, WRITE);
}
/**
* drbd_bm_write_sect: Writes a 512 (MD_SECTOR_SIZE) byte piece of the bitmap
* @mdev: DRBD device.
* @enr: Extent number in the resync lru (happens to be sector offset)
*
* The BM_EXT_SIZE is on purpose exactly the amount of the bitmap covered
* by a single sector write. Therefore enr == sector offset from the
* start of the bitmap.
*/
int drbd_bm_write_sect(struct drbd_conf *mdev, unsigned long enr) __must_hold(local)
{
sector_t on_disk_sector = enr + mdev->ldev->md.md_offset
+ mdev->ldev->md.bm_offset;
int bm_words, num_words, offset;
int err = 0;
mutex_lock(&mdev->md_io_mutex);
bm_words = drbd_bm_words(mdev);
offset = S2W(enr); /* word offset into bitmap */
num_words = min(S2W(1), bm_words - offset);
if (num_words < S2W(1))
memset(page_address(mdev->md_io_page), 0, MD_SECTOR_SIZE);
drbd_bm_get_lel(mdev, offset, num_words,
page_address(mdev->md_io_page));
if (!drbd_md_sync_page_io(mdev, mdev->ldev, on_disk_sector, WRITE)) {
int i;
err = -EIO;
dev_err(DEV, "IO ERROR writing bitmap sector %lu "
"(meta-disk sector %llus)\n",
enr, (unsigned long long)on_disk_sector);
drbd_chk_io_error(mdev, 1, TRUE);
for (i = 0; i < AL_EXT_PER_BM_SECT; i++)
drbd_bm_ALe_set_all(mdev, enr*AL_EXT_PER_BM_SECT+i);
}
mdev->bm_writ_cnt++;
mutex_unlock(&mdev->md_io_mutex);
return err;
}
/* NOTE
* find_first_bit returns int, we return unsigned long.
* should not make much difference anyways, but ...
*
* this returns a bit number, NOT a sector!
*/
#define BPP_MASK ((1UL << (PAGE_SHIFT+3)) - 1)
static unsigned long __bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo,
const int find_zero_bit, const enum km_type km)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long i = -1UL;
unsigned long *p_addr;
unsigned long bit_offset; /* bit offset of the mapped page. */
if (bm_fo > b->bm_bits) {
dev_err(DEV, "bm_fo=%lu bm_bits=%lu\n", bm_fo, b->bm_bits);
} else {
while (bm_fo < b->bm_bits) {
unsigned long offset;
bit_offset = bm_fo & ~BPP_MASK; /* bit offset of the page */
offset = bit_offset >> LN2_BPL; /* word offset of the page */
p_addr = __bm_map_paddr(b, offset, km);
if (find_zero_bit)
i = find_next_zero_bit(p_addr, PAGE_SIZE*8, bm_fo & BPP_MASK);
else
i = find_next_bit(p_addr, PAGE_SIZE*8, bm_fo & BPP_MASK);
__bm_unmap(p_addr, km);
if (i < PAGE_SIZE*8) {
i = bit_offset + i;
if (i >= b->bm_bits)
break;
goto found;
}
bm_fo = bit_offset + PAGE_SIZE*8;
}
i = -1UL;
}
found:
return i;
}
static unsigned long bm_find_next(struct drbd_conf *mdev,
unsigned long bm_fo, const int find_zero_bit)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long i = -1UL;
ERR_IF(!b) return i;
ERR_IF(!b->bm_pages) return i;
spin_lock_irq(&b->bm_lock);
if (bm_is_locked(b))
bm_print_lock_info(mdev);
i = __bm_find_next(mdev, bm_fo, find_zero_bit, KM_IRQ1);
spin_unlock_irq(&b->bm_lock);
return i;
}
unsigned long drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo)
{
return bm_find_next(mdev, bm_fo, 0);
}
#if 0
/* not yet needed for anything. */
unsigned long drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo)
{
return bm_find_next(mdev, bm_fo, 1);
}
#endif
/* does not spin_lock_irqsave.
* you must take drbd_bm_lock() first */
unsigned long _drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo)
{
/* WARN_ON(!bm_is_locked(mdev)); */
return __bm_find_next(mdev, bm_fo, 0, KM_USER1);
}
unsigned long _drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo)
{
/* WARN_ON(!bm_is_locked(mdev)); */
return __bm_find_next(mdev, bm_fo, 1, KM_USER1);
}
/* returns number of bits actually changed.
* for val != 0, we change 0 -> 1, return code positive
* for val == 0, we change 1 -> 0, return code negative
* wants bitnr, not sector.
* expected to be called for only a few bits (e - s about BITS_PER_LONG).
* Must hold bitmap lock already. */
static int __bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
unsigned long e, int val, const enum km_type km)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr = NULL;
unsigned long bitnr;
unsigned long last_page_nr = -1UL;
int c = 0;
if (e >= b->bm_bits) {
dev_err(DEV, "ASSERT FAILED: bit_s=%lu bit_e=%lu bm_bits=%lu\n",
s, e, b->bm_bits);
e = b->bm_bits ? b->bm_bits -1 : 0;
}
for (bitnr = s; bitnr <= e; bitnr++) {
unsigned long offset = bitnr>>LN2_BPL;
unsigned long page_nr = offset >> (PAGE_SHIFT - LN2_BPL + 3);
if (page_nr != last_page_nr) {
if (p_addr)
__bm_unmap(p_addr, km);
p_addr = __bm_map_paddr(b, offset, km);
last_page_nr = page_nr;
}
if (val)
c += (0 == __test_and_set_bit(bitnr & BPP_MASK, p_addr));
else
c -= (0 != __test_and_clear_bit(bitnr & BPP_MASK, p_addr));
}
if (p_addr)
__bm_unmap(p_addr, km);
b->bm_set += c;
return c;
}
/* returns number of bits actually changed.
* for val != 0, we change 0 -> 1, return code positive
* for val == 0, we change 1 -> 0, return code negative
* wants bitnr, not sector */
static int bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
const unsigned long e, int val)
{
unsigned long flags;
struct drbd_bitmap *b = mdev->bitmap;
int c = 0;
ERR_IF(!b) return 1;
ERR_IF(!b->bm_pages) return 0;
spin_lock_irqsave(&b->bm_lock, flags);
if (bm_is_locked(b))
bm_print_lock_info(mdev);
c = __bm_change_bits_to(mdev, s, e, val, KM_IRQ1);
spin_unlock_irqrestore(&b->bm_lock, flags);
return c;
}
/* returns number of bits changed 0 -> 1 */
int drbd_bm_set_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
{
return bm_change_bits_to(mdev, s, e, 1);
}
/* returns number of bits changed 1 -> 0 */
int drbd_bm_clear_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
{
return -bm_change_bits_to(mdev, s, e, 0);
}
/* sets all bits in full words,
* from first_word up to, but not including, last_word */
static inline void bm_set_full_words_within_one_page(struct drbd_bitmap *b,
int page_nr, int first_word, int last_word)
{
int i;
int bits;
unsigned long *paddr = kmap_atomic(b->bm_pages[page_nr], KM_USER0);
for (i = first_word; i < last_word; i++) {
bits = hweight_long(paddr[i]);
paddr[i] = ~0UL;
b->bm_set += BITS_PER_LONG - bits;
}
kunmap_atomic(paddr, KM_USER0);
}
/* Same thing as drbd_bm_set_bits, but without taking the spin_lock_irqsave.
* You must first drbd_bm_lock().
* Can be called to set the whole bitmap in one go.
* Sets bits from s to e _inclusive_. */
void _drbd_bm_set_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
{
/* First set_bit from the first bit (s)
* up to the next long boundary (sl),
* then assign full words up to the last long boundary (el),
* then set_bit up to and including the last bit (e).
*
* Do not use memset, because we must account for changes,
* so we need to loop over the words with hweight() anyways.
*/
unsigned long sl = ALIGN(s,BITS_PER_LONG);
unsigned long el = (e+1) & ~((unsigned long)BITS_PER_LONG-1);
int first_page;
int last_page;
int page_nr;
int first_word;
int last_word;
if (e - s <= 3*BITS_PER_LONG) {
/* don't bother; el and sl may even be wrong. */
__bm_change_bits_to(mdev, s, e, 1, KM_USER0);
return;
}
/* difference is large enough that we can trust sl and el */
/* bits filling the current long */
if (sl)
__bm_change_bits_to(mdev, s, sl-1, 1, KM_USER0);
first_page = sl >> (3 + PAGE_SHIFT);
last_page = el >> (3 + PAGE_SHIFT);
/* MLPP: modulo longs per page */
/* LWPP: long words per page */
first_word = MLPP(sl >> LN2_BPL);
last_word = LWPP;
/* first and full pages, unless first page == last page */
for (page_nr = first_page; page_nr < last_page; page_nr++) {
bm_set_full_words_within_one_page(mdev->bitmap, page_nr, first_word, last_word);
cond_resched();
first_word = 0;
}
/* last page (respectively only page, for first page == last page) */
last_word = MLPP(el >> LN2_BPL);
bm_set_full_words_within_one_page(mdev->bitmap, last_page, first_word, last_word);
/* possibly trailing bits.
* example: (e & 63) == 63, el will be e+1.
* if that even was the very last bit,
* it would trigger an assert in __bm_change_bits_to()
*/
if (el <= e)
__bm_change_bits_to(mdev, el, e, 1, KM_USER0);
}
/* returns bit state
* wants bitnr, NOT sector.
* inherently racy... area needs to be locked by means of {al,rs}_lru
* 1 ... bit set
* 0 ... bit not set
* -1 ... first out of bounds access, stop testing for bits!
*/
int drbd_bm_test_bit(struct drbd_conf *mdev, const unsigned long bitnr)
{
unsigned long flags;
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr;
int i;
ERR_IF(!b) return 0;
ERR_IF(!b->bm_pages) return 0;
spin_lock_irqsave(&b->bm_lock, flags);
if (bm_is_locked(b))
bm_print_lock_info(mdev);
if (bitnr < b->bm_bits) {
unsigned long offset = bitnr>>LN2_BPL;
p_addr = bm_map_paddr(b, offset);
i = test_bit(bitnr & BPP_MASK, p_addr) ? 1 : 0;
bm_unmap(p_addr);
} else if (bitnr == b->bm_bits) {
i = -1;
} else { /* (bitnr > b->bm_bits) */
dev_err(DEV, "bitnr=%lu > bm_bits=%lu\n", bitnr, b->bm_bits);
i = 0;
}
spin_unlock_irqrestore(&b->bm_lock, flags);
return i;
}
/* returns number of bits set in the range [s, e] */
int drbd_bm_count_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
{
unsigned long flags;
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr = NULL, page_nr = -1;
unsigned long bitnr;
int c = 0;
size_t w;
/* If this is called without a bitmap, that is a bug. But just to be
* robust in case we screwed up elsewhere, in that case pretend there
* was one dirty bit in the requested area, so we won't try to do a
* local read there (no bitmap probably implies no disk) */
ERR_IF(!b) return 1;
ERR_IF(!b->bm_pages) return 1;
spin_lock_irqsave(&b->bm_lock, flags);
if (bm_is_locked(b))
bm_print_lock_info(mdev);
for (bitnr = s; bitnr <= e; bitnr++) {
w = bitnr >> LN2_BPL;
if (page_nr != w >> (PAGE_SHIFT - LN2_BPL + 3)) {
page_nr = w >> (PAGE_SHIFT - LN2_BPL + 3);
if (p_addr)
bm_unmap(p_addr);
p_addr = bm_map_paddr(b, w);
}
ERR_IF (bitnr >= b->bm_bits) {
dev_err(DEV, "bitnr=%lu bm_bits=%lu\n", bitnr, b->bm_bits);
} else {
c += (0 != test_bit(bitnr - (page_nr << (PAGE_SHIFT+3)), p_addr));
}
}
if (p_addr)
bm_unmap(p_addr);
spin_unlock_irqrestore(&b->bm_lock, flags);
return c;
}
/* inherently racy...
* return value may be already out-of-date when this function returns.
* but the general usage is that this is only use during a cstate when bits are
* only cleared, not set, and typically only care for the case when the return
* value is zero, or we already "locked" this "bitmap extent" by other means.
*
* enr is bm-extent number, since we chose to name one sector (512 bytes)
* worth of the bitmap a "bitmap extent".
*
* TODO
* I think since we use it like a reference count, we should use the real
* reference count of some bitmap extent element from some lru instead...
*
*/
int drbd_bm_e_weight(struct drbd_conf *mdev, unsigned long enr)
{
struct drbd_bitmap *b = mdev->bitmap;
int count, s, e;
unsigned long flags;
unsigned long *p_addr, *bm;
ERR_IF(!b) return 0;
ERR_IF(!b->bm_pages) return 0;
spin_lock_irqsave(&b->bm_lock, flags);
if (bm_is_locked(b))
bm_print_lock_info(mdev);
s = S2W(enr);
e = min((size_t)S2W(enr+1), b->bm_words);
count = 0;
if (s < b->bm_words) {
int n = e-s;
p_addr = bm_map_paddr(b, s);
bm = p_addr + MLPP(s);
while (n--)
count += hweight_long(*bm++);
bm_unmap(p_addr);
} else {
dev_err(DEV, "start offset (%d) too large in drbd_bm_e_weight\n", s);
}
spin_unlock_irqrestore(&b->bm_lock, flags);
return count;
}
/* set all bits covered by the AL-extent al_enr */
unsigned long drbd_bm_ALe_set_all(struct drbd_conf *mdev, unsigned long al_enr)
{
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr, *bm;
unsigned long weight;
int count, s, e, i, do_now;
ERR_IF(!b) return 0;
ERR_IF(!b->bm_pages) return 0;
spin_lock_irq(&b->bm_lock);
if (bm_is_locked(b))
bm_print_lock_info(mdev);
weight = b->bm_set;
s = al_enr * BM_WORDS_PER_AL_EXT;
e = min_t(size_t, s + BM_WORDS_PER_AL_EXT, b->bm_words);
/* assert that s and e are on the same page */
D_ASSERT((e-1) >> (PAGE_SHIFT - LN2_BPL + 3)
== s >> (PAGE_SHIFT - LN2_BPL + 3));
count = 0;
if (s < b->bm_words) {
i = do_now = e-s;
p_addr = bm_map_paddr(b, s);
bm = p_addr + MLPP(s);
while (i--) {
count += hweight_long(*bm);
*bm = -1UL;
bm++;
}
bm_unmap(p_addr);
b->bm_set += do_now*BITS_PER_LONG - count;
if (e == b->bm_words)
b->bm_set -= bm_clear_surplus(b);
} else {
dev_err(DEV, "start offset (%d) too large in drbd_bm_ALe_set_all\n", s);
}
weight = b->bm_set - weight;
spin_unlock_irq(&b->bm_lock);
return weight;
}
