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linux/drivers/block/drbd/drbd_actlog.c

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/*
drbd_actlog.c
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
Copyright (C) 2003-2008, 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/slab.h>
#include <linux/drbd.h>
#include "drbd_int.h"
#include "drbd_wrappers.h"
/* We maintain a trivial check sum in our on disk activity log.
* With that we can ensure correct operation even when the storage
* device might do a partial (last) sector write while loosing power.
*/
struct __packed al_transaction {
u32 magic;
u32 tr_number;
struct __packed {
u32 pos;
u32 extent; } updates[1 + AL_EXTENTS_PT];
u32 xor_sum;
};
struct update_odbm_work {
struct drbd_work w;
unsigned int enr;
};
struct update_al_work {
struct drbd_work w;
struct lc_element *al_ext;
struct completion event;
unsigned int enr;
/* if old_enr != LC_FREE, write corresponding bitmap sector, too */
unsigned int old_enr;
};
struct drbd_atodb_wait {
atomic_t count;
struct completion io_done;
struct drbd_conf *mdev;
int error;
};
int w_al_write_transaction(struct drbd_conf *, struct drbd_work *, int);
static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
struct drbd_backing_dev *bdev,
struct page *page, sector_t sector,
int rw, int size)
{
struct bio *bio;
struct drbd_md_io md_io;
int ok;
md_io.mdev = mdev;
init_completion(&md_io.event);
md_io.error = 0;
if ((rw & WRITE) && !test_bit(MD_NO_BARRIER, &mdev->flags))
rw |= (1 << BIO_RW_BARRIER);
rw |= ((1<<BIO_RW_UNPLUG) | (1<<BIO_RW_SYNCIO));
retry:
bio = bio_alloc(GFP_NOIO, 1);
bio->bi_bdev = bdev->md_bdev;
bio->bi_sector = sector;
ok = (bio_add_page(bio, page, size, 0) == size);
if (!ok)
goto out;
bio->bi_private = &md_io;
bio->bi_end_io = drbd_md_io_complete;
bio->bi_rw = rw;
if (FAULT_ACTIVE(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
bio_endio(bio, -EIO);
else
submit_bio(rw, bio);
wait_for_completion(&md_io.event);
ok = bio_flagged(bio, BIO_UPTODATE) && md_io.error == 0;
/* check for unsupported barrier op.
* would rather check on EOPNOTSUPP, but that is not reliable.
* don't try again for ANY return value != 0 */
if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER) && !ok)) {
/* Try again with no barrier */
dev_warn(DEV, "Barriers not supported on meta data device - disabling\n");
set_bit(MD_NO_BARRIER, &mdev->flags);
rw &= ~(1 << BIO_RW_BARRIER);
bio_put(bio);
goto retry;
}
out:
bio_put(bio);
return ok;
}
int drbd_md_sync_page_io(struct drbd_conf *mdev, struct drbd_backing_dev *bdev,
sector_t sector, int rw)
{
int logical_block_size, mask, ok;
int offset = 0;
struct page *iop = mdev->md_io_page;
D_ASSERT(mutex_is_locked(&mdev->md_io_mutex));
BUG_ON(!bdev->md_bdev);
logical_block_size = bdev_logical_block_size(bdev->md_bdev);
if (logical_block_size == 0)
logical_block_size = MD_SECTOR_SIZE;
/* in case logical_block_size != 512 [ s390 only? ] */
if (logical_block_size != MD_SECTOR_SIZE) {
mask = (logical_block_size / MD_SECTOR_SIZE) - 1;
D_ASSERT(mask == 1 || mask == 3 || mask == 7);
D_ASSERT(logical_block_size == (mask+1) * MD_SECTOR_SIZE);
offset = sector & mask;
sector = sector & ~mask;
iop = mdev->md_io_tmpp;
if (rw & WRITE) {
/* these are GFP_KERNEL pages, pre-allocated
* on device initialization */
void *p = page_address(mdev->md_io_page);
void *hp = page_address(mdev->md_io_tmpp);
ok = _drbd_md_sync_page_io(mdev, bdev, iop, sector,
READ, logical_block_size);
if (unlikely(!ok)) {
dev_err(DEV, "drbd_md_sync_page_io(,%llus,"
"READ [logical_block_size!=512]) failed!\n",
(unsigned long long)sector);
return 0;
}
memcpy(hp + offset*MD_SECTOR_SIZE, p, MD_SECTOR_SIZE);
}
}
if (sector < drbd_md_first_sector(bdev) ||
sector > drbd_md_last_sector(bdev))
dev_alert(DEV, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
current->comm, current->pid, __func__,
(unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
ok = _drbd_md_sync_page_io(mdev, bdev, iop, sector, rw, logical_block_size);
if (unlikely(!ok)) {
dev_err(DEV, "drbd_md_sync_page_io(,%llus,%s) failed!\n",
(unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
return 0;
}
if (logical_block_size != MD_SECTOR_SIZE && !(rw & WRITE)) {
void *p = page_address(mdev->md_io_page);
void *hp = page_address(mdev->md_io_tmpp);
memcpy(p, hp + offset*MD_SECTOR_SIZE, MD_SECTOR_SIZE);
}
return ok;
}
static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr)
{
struct lc_element *al_ext;
struct lc_element *tmp;
unsigned long al_flags = 0;
spin_lock_irq(&mdev->al_lock);
tmp = lc_find(mdev->resync, enr/AL_EXT_PER_BM_SECT);
if (unlikely(tmp != NULL)) {
struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
spin_unlock_irq(&mdev->al_lock);
return NULL;
}
}
al_ext = lc_get(mdev->act_log, enr);
al_flags = mdev->act_log->flags;
spin_unlock_irq(&mdev->al_lock);
/*
if (!al_ext) {
if (al_flags & LC_STARVING)
dev_warn(DEV, "Have to wait for LRU element (AL too small?)\n");
if (al_flags & LC_DIRTY)
dev_warn(DEV, "Ongoing AL update (AL device too slow?)\n");
}
*/
return al_ext;
}
void drbd_al_begin_io(struct drbd_conf *mdev, sector_t sector)
{
unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
struct lc_element *al_ext;
struct update_al_work al_work;
D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
wait_event(mdev->al_wait, (al_ext = _al_get(mdev, enr)));
if (al_ext->lc_number != enr) {
/* drbd_al_write_transaction(mdev,al_ext,enr);
* recurses into generic_make_request(), which
* disallows recursion, bios being serialized on the
* current->bio_tail list now.
* we have to delegate updates to the activity log
* to the worker thread. */
init_completion(&al_work.event);
al_work.al_ext = al_ext;
al_work.enr = enr;
al_work.old_enr = al_ext->lc_number;
al_work.w.cb = w_al_write_transaction;
drbd_queue_work_front(&mdev->data.work, &al_work.w);
wait_for_completion(&al_work.event);
mdev->al_writ_cnt++;
spin_lock_irq(&mdev->al_lock);
lc_changed(mdev->act_log, al_ext);
spin_unlock_irq(&mdev->al_lock);
wake_up(&mdev->al_wait);
}
}
void drbd_al_complete_io(struct drbd_conf *mdev, sector_t sector)
{
unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
struct lc_element *extent;
unsigned long flags;
spin_lock_irqsave(&mdev->al_lock, flags);
extent = lc_find(mdev->act_log, enr);
if (!extent) {
spin_unlock_irqrestore(&mdev->al_lock, flags);
dev_err(DEV, "al_complete_io() called on inactive extent %u\n", enr);
return;
}
if (lc_put(mdev->act_log, extent) == 0)
wake_up(&mdev->al_wait);
spin_unlock_irqrestore(&mdev->al_lock, flags);
}
int
w_al_write_transaction(struct drbd_conf *mdev, struct drbd_work *w, int unused)
{
struct update_al_work *aw = container_of(w, struct update_al_work, w);
struct lc_element *updated = aw->al_ext;
const unsigned int new_enr = aw->enr;
const unsigned int evicted = aw->old_enr;
struct al_transaction *buffer;
sector_t sector;
int i, n, mx;
unsigned int extent_nr;
u32 xor_sum = 0;
if (!get_ldev(mdev)) {
dev_err(DEV, "get_ldev() failed in w_al_write_transaction\n");
complete(&((struct update_al_work *)w)->event);
return 1;
}
/* do we have to do a bitmap write, first?
* TODO reduce maximum latency:
* submit both bios, then wait for both,
* instead of doing two synchronous sector writes. */
if (mdev->state.conn < C_CONNECTED && evicted != LC_FREE)
drbd_bm_write_sect(mdev, evicted/AL_EXT_PER_BM_SECT);
mutex_lock(&mdev->md_io_mutex); /* protects md_io_page, al_tr_cycle, ... */
buffer = (struct al_transaction *)page_address(mdev->md_io_page);
buffer->magic = __constant_cpu_to_be32(DRBD_MAGIC);
buffer->tr_number = cpu_to_be32(mdev->al_tr_number);
n = lc_index_of(mdev->act_log, updated);
buffer->updates[0].pos = cpu_to_be32(n);
buffer->updates[0].extent = cpu_to_be32(new_enr);
xor_sum ^= new_enr;
mx = min_t(int, AL_EXTENTS_PT,
mdev->act_log->nr_elements - mdev->al_tr_cycle);
for (i = 0; i < mx; i++) {
unsigned idx = mdev->al_tr_cycle + i;
extent_nr = lc_element_by_index(mdev->act_log, idx)->lc_number;
buffer->updates[i+1].pos = cpu_to_be32(idx);
buffer->updates[i+1].extent = cpu_to_be32(extent_nr);
xor_sum ^= extent_nr;
}
for (; i < AL_EXTENTS_PT; i++) {
buffer->updates[i+1].pos = __constant_cpu_to_be32(-1);
buffer->updates[i+1].extent = __constant_cpu_to_be32(LC_FREE);
xor_sum ^= LC_FREE;
}
mdev->al_tr_cycle += AL_EXTENTS_PT;
if (mdev->al_tr_cycle >= mdev->act_log->nr_elements)
mdev->al_tr_cycle = 0;
buffer->xor_sum = cpu_to_be32(xor_sum);
sector = mdev->ldev->md.md_offset
+ mdev->ldev->md.al_offset + mdev->al_tr_pos;
if (!drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE))
drbd_chk_io_error(mdev, 1, TRUE);
if (++mdev->al_tr_pos >
div_ceil(mdev->act_log->nr_elements, AL_EXTENTS_PT))
mdev->al_tr_pos = 0;
D_ASSERT(mdev->al_tr_pos < MD_AL_MAX_SIZE);
mdev->al_tr_number++;
mutex_unlock(&mdev->md_io_mutex);
complete(&((struct update_al_work *)w)->event);
put_ldev(mdev);
return 1;
}
/**
* drbd_al_read_tr() - Read a single transaction from the on disk activity log
* @mdev: DRBD device.
* @bdev: Block device to read form.
* @b: pointer to an al_transaction.
* @index: On disk slot of the transaction to read.
*
* Returns -1 on IO error, 0 on checksum error and 1 upon success.
*/
static int drbd_al_read_tr(struct drbd_conf *mdev,
struct drbd_backing_dev *bdev,
struct al_transaction *b,
int index)
{
sector_t sector;
int rv, i;
u32 xor_sum = 0;
sector = bdev->md.md_offset + bdev->md.al_offset + index;
/* Dont process error normally,
* as this is done before disk is attached! */
if (!drbd_md_sync_page_io(mdev, bdev, sector, READ))
return -1;
rv = (be32_to_cpu(b->magic) == DRBD_MAGIC);
for (i = 0; i < AL_EXTENTS_PT + 1; i++)
xor_sum ^= be32_to_cpu(b->updates[i].extent);
rv &= (xor_sum == be32_to_cpu(b->xor_sum));
return rv;
}
/**
* drbd_al_read_log() - Restores the activity log from its on disk representation.
* @mdev: DRBD device.
* @bdev: Block device to read form.
*
* Returns 1 on success, returns 0 when reading the log failed due to IO errors.
*/
int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
{
struct al_transaction *buffer;
int i;
int rv;
int mx;
int active_extents = 0;
int transactions = 0;
int found_valid = 0;
int from = 0;
int to = 0;
u32 from_tnr = 0;
u32 to_tnr = 0;
u32 cnr;
mx = div_ceil(mdev->act_log->nr_elements, AL_EXTENTS_PT);
/* lock out all other meta data io for now,
* and make sure the page is mapped.
*/
mutex_lock(&mdev->md_io_mutex);
buffer = page_address(mdev->md_io_page);
/* Find the valid transaction in the log */
for (i = 0; i <= mx; i++) {
rv = drbd_al_read_tr(mdev, bdev, buffer, i);
if (rv == 0)
continue;
if (rv == -1) {
mutex_unlock(&mdev->md_io_mutex);
return 0;
}
cnr = be32_to_cpu(buffer->tr_number);
if (++found_valid == 1) {
from = i;
to = i;
from_tnr = cnr;
to_tnr = cnr;
continue;
}
if ((int)cnr - (int)from_tnr < 0) {
D_ASSERT(from_tnr - cnr + i - from == mx+1);
from = i;
from_tnr = cnr;
}
if ((int)cnr - (int)to_tnr > 0) {
D_ASSERT(cnr - to_tnr == i - to);
to = i;
to_tnr = cnr;
}
}
if (!found_valid) {
dev_warn(DEV, "No usable activity log found.\n");
mutex_unlock(&mdev->md_io_mutex);
return 1;
}
/* Read the valid transactions.
* dev_info(DEV, "Reading from %d to %d.\n",from,to); */
i = from;
while (1) {
int j, pos;
unsigned int extent_nr;
unsigned int trn;
rv = drbd_al_read_tr(mdev, bdev, buffer, i);
ERR_IF(rv == 0) goto cancel;
if (rv == -1) {
mutex_unlock(&mdev->md_io_mutex);
return 0;
}
trn = be32_to_cpu(buffer->tr_number);
spin_lock_irq(&mdev->al_lock);
/* This loop runs backwards because in the cyclic
elements there might be an old version of the
updated element (in slot 0). So the element in slot 0
can overwrite old versions. */
for (j = AL_EXTENTS_PT; j >= 0; j--) {
pos = be32_to_cpu(buffer->updates[j].pos);
extent_nr = be32_to_cpu(buffer->updates[j].extent);
if (extent_nr == LC_FREE)
continue;
lc_set(mdev->act_log, extent_nr, pos);
active_extents++;
}
spin_unlock_irq(&mdev->al_lock);
transactions++;
cancel:
if (i == to)
break;
i++;
if (i > mx)
i = 0;
}
mdev->al_tr_number = to_tnr+1;
mdev->al_tr_pos = to;
if (++mdev->al_tr_pos >
div_ceil(mdev->act_log->nr_elements, AL_EXTENTS_PT))
mdev->al_tr_pos = 0;
/* ok, we are done with it */
mutex_unlock(&mdev->md_io_mutex);
dev_info(DEV, "Found %d transactions (%d active extents) in activity log.\n",
transactions, active_extents);
return 1;
}
static void atodb_endio(struct bio *bio, int error)
{
struct drbd_atodb_wait *wc = bio->bi_private;
struct drbd_conf *mdev = wc->mdev;
struct page *page;
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?! */
if (!error && !uptodate)
error = -EIO;
drbd_chk_io_error(mdev, error, TRUE);
if (error && wc->error == 0)
wc->error = error;
if (atomic_dec_and_test(&wc->count))
complete(&wc->io_done);
page = bio->bi_io_vec[0].bv_page;
put_page(page);
bio_put(bio);
mdev->bm_writ_cnt++;
put_ldev(mdev);
}
/* sector to word */
#define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL))
/* activity log to on disk bitmap -- prepare bio unless that sector
* is already covered by previously prepared bios */
static int atodb_prepare_unless_covered(struct drbd_conf *mdev,
struct bio **bios,
unsigned int enr,
struct drbd_atodb_wait *wc) __must_hold(local)
{
struct bio *bio;
struct page *page;
sector_t on_disk_sector;
unsigned int page_offset = PAGE_SIZE;
int offset;
int i = 0;
int err = -ENOMEM;
/* We always write aligned, full 4k blocks,
* so we can ignore the logical_block_size (for now) */
enr &= ~7U;
on_disk_sector = enr + mdev->ldev->md.md_offset
+ mdev->ldev->md.bm_offset;
D_ASSERT(!(on_disk_sector & 7U));
/* Check if that enr is already covered by an already created bio.
* Caution, bios[] is not NULL terminated,
* but only initialized to all NULL.
* For completely scattered activity log,
* the last invocation iterates over all bios,
* and finds the last NULL entry.
*/
while ((bio = bios[i])) {
if (bio->bi_sector == on_disk_sector)
return 0;
i++;
}
/* bios[i] == NULL, the next not yet used slot */
/* GFP_KERNEL, we are not in the write-out path */
bio = bio_alloc(GFP_KERNEL, 1);
if (bio == NULL)
return -ENOMEM;
if (i > 0) {
const struct bio_vec *prev_bv = bios[i-1]->bi_io_vec;
page_offset = prev_bv->bv_offset + prev_bv->bv_len;
page = prev_bv->bv_page;
}
if (page_offset == PAGE_SIZE) {
page = alloc_page(__GFP_HIGHMEM);
if (page == NULL)
goto out_bio_put;
page_offset = 0;
} else {
get_page(page);
}
offset = S2W(enr);
drbd_bm_get_lel(mdev, offset,
min_t(size_t, S2W(8), drbd_bm_words(mdev) - offset),
kmap(page) + page_offset);
kunmap(page);
bio->bi_private = wc;
bio->bi_end_io = atodb_endio;
bio->bi_bdev = mdev->ldev->md_bdev;
bio->bi_sector = on_disk_sector;
if (bio_add_page(bio, page, 4096, page_offset) != 4096)
goto out_put_page;
atomic_inc(&wc->count);
/* we already know that we may do this...
* get_ldev_if_state(mdev,D_ATTACHING);
* just get the extra reference, so that the local_cnt reflects
* the number of pending IO requests DRBD at its backing device.
*/
atomic_inc(&mdev->local_cnt);
bios[i] = bio;
return 0;
out_put_page:
err = -EINVAL;
put_page(page);
out_bio_put:
bio_put(bio);
return err;
}
/**
* drbd_al_to_on_disk_bm() - * Writes bitmap parts covered by active AL extents
* @mdev: DRBD device.
*
* Called when we detach (unconfigure) local storage,
* or when we go from R_PRIMARY to R_SECONDARY role.
*/
void drbd_al_to_on_disk_bm(struct drbd_conf *mdev)
{
int i, nr_elements;
unsigned int enr;
struct bio **bios;
struct drbd_atodb_wait wc;
ERR_IF (!get_ldev_if_state(mdev, D_ATTACHING))
return; /* sorry, I don't have any act_log etc... */
wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
nr_elements = mdev->act_log->nr_elements;
/* GFP_KERNEL, we are not in anyone's write-out path */
bios = kzalloc(sizeof(struct bio *) * nr_elements, GFP_KERNEL);
if (!bios)
goto submit_one_by_one;
atomic_set(&wc.count, 0);
init_completion(&wc.io_done);
wc.mdev = mdev;
wc.error = 0;
for (i = 0; i < nr_elements; i++) {
enr = lc_element_by_index(mdev->act_log, i)->lc_number;
if (enr == LC_FREE)
continue;
/* next statement also does atomic_inc wc.count and local_cnt */
if (atodb_prepare_unless_covered(mdev, bios,
enr/AL_EXT_PER_BM_SECT,
&wc))
goto free_bios_submit_one_by_one;
}
/* unnecessary optimization? */
lc_unlock(mdev->act_log);
wake_up(&mdev->al_wait);
/* all prepared, submit them */
for (i = 0; i < nr_elements; i++) {
if (bios[i] == NULL)
break;
if (FAULT_ACTIVE(mdev, DRBD_FAULT_MD_WR)) {
bios[i]->bi_rw = WRITE;
bio_endio(bios[i], -EIO);
} else {
submit_bio(WRITE, bios[i]);
}
}
drbd_blk_run_queue(bdev_get_queue(mdev->ldev->md_bdev));
/* always (try to) flush bitmap to stable storage */
drbd_md_flush(mdev);
/* In case we did not submit a single IO do not wait for
* them to complete. ( Because we would wait forever here. )
*
* In case we had IOs and they are already complete, there
* is not point in waiting anyways.
* Therefore this if () ... */
if (atomic_read(&wc.count))
wait_for_completion(&wc.io_done);
put_ldev(mdev);
kfree(bios);
return;
free_bios_submit_one_by_one:
/* free everything by calling the endio callback directly. */
for (i = 0; i < nr_elements && bios[i]; i++)
bio_endio(bios[i], 0);
kfree(bios);
submit_one_by_one:
dev_warn(DEV, "Using the slow drbd_al_to_on_disk_bm()\n");
for (i = 0; i < mdev->act_log->nr_elements; i++) {
enr = lc_element_by_index(mdev->act_log, i)->lc_number;
if (enr == LC_FREE)
continue;
/* Really slow: if we have al-extents 16..19 active,
* sector 4 will be written four times! Synchronous! */
drbd_bm_write_sect(mdev, enr/AL_EXT_PER_BM_SECT);
}
lc_unlock(mdev->act_log);
wake_up(&mdev->al_wait);
put_ldev(mdev);
}
/**
* drbd_al_apply_to_bm() - Sets the bitmap to diry(1) where covered ba active AL extents
* @mdev: DRBD device.
*/
void drbd_al_apply_to_bm(struct drbd_conf *mdev)
{
unsigned int enr;
unsigned long add = 0;
char ppb[10];
int i;
wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
for (i = 0; i < mdev->act_log->nr_elements; i++) {
enr = lc_element_by_index(mdev->act_log, i)->lc_number;
if (enr == LC_FREE)
continue;
add += drbd_bm_ALe_set_all(mdev, enr);
}
lc_unlock(mdev->act_log);
wake_up(&mdev->al_wait);
dev_info(DEV, "Marked additional %s as out-of-sync based on AL.\n",
ppsize(ppb, Bit2KB(add)));
}
static int _try_lc_del(struct drbd_conf *mdev, struct lc_element *al_ext)
{
int rv;
spin_lock_irq(&mdev->al_lock);
rv = (al_ext->refcnt == 0);
if (likely(rv))
lc_del(mdev->act_log, al_ext);
spin_unlock_irq(&mdev->al_lock);
return rv;
}
/**
* drbd_al_shrink() - Removes all active extents form the activity log
* @mdev: DRBD device.
*
* Removes all active extents form the activity log, waiting until
* the reference count of each entry dropped to 0 first, of course.
*
* You need to lock mdev->act_log with lc_try_lock() / lc_unlock()
*/
void drbd_al_shrink(struct drbd_conf *mdev)
{
struct lc_element *al_ext;
int i;
D_ASSERT(test_bit(__LC_DIRTY, &mdev->act_log->flags));
for (i = 0; i < mdev->act_log->nr_elements; i++) {
al_ext = lc_element_by_index(mdev->act_log, i);
if (al_ext->lc_number == LC_FREE)
continue;
wait_event(mdev->al_wait, _try_lc_del(mdev, al_ext));
}
wake_up(&mdev->al_wait);
}
static int w_update_odbm(struct drbd_conf *mdev, struct drbd_work *w, int unused)
{
struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
if (!get_ldev(mdev)) {
if (__ratelimit(&drbd_ratelimit_state))
dev_warn(DEV, "Can not update on disk bitmap, local IO disabled.\n");
kfree(udw);
return 1;
}
drbd_bm_write_sect(mdev, udw->enr);
put_ldev(mdev);
kfree(udw);
if (drbd_bm_total_weight(mdev) <= mdev->rs_failed) {
switch (mdev->state.conn) {
case C_SYNC_SOURCE: case C_SYNC_TARGET:
case C_PAUSED_SYNC_S: case C_PAUSED_SYNC_T:
drbd_resync_finished(mdev);
default:
/* nothing to do */
break;
}
}
drbd_bcast_sync_progress(mdev);
return 1;
}
/* ATTENTION. The AL's extents are 4MB each, while the extents in the
* resync LRU-cache are 16MB each.
* The caller of this function has to hold an get_ldev() reference.
*
* TODO will be obsoleted once we have a caching lru of the on disk bitmap
*/
static void drbd_try_clear_on_disk_bm(struct drbd_conf *mdev, sector_t sector,
int count, int success)
{
struct lc_element *e;
struct update_odbm_work *udw;
unsigned int enr;
D_ASSERT(atomic_read(&mdev->local_cnt));
/* I simply assume that a sector/size pair never crosses
* a 16 MB extent border. (Currently this is true...) */
enr = BM_SECT_TO_EXT(sector);
e = lc_get(mdev->resync, enr);
if (e) {
struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
if (ext->lce.lc_number == enr) {
if (success)
ext->rs_left -= count;
else
ext->rs_failed += count;
if (ext->rs_left < ext->rs_failed) {
dev_err(DEV, "BAD! sector=%llus enr=%u rs_left=%d "
"rs_failed=%d count=%d\n",
(unsigned long long)sector,
ext->lce.lc_number, ext->rs_left,
ext->rs_failed, count);
dump_stack();
lc_put(mdev->resync, &ext->lce);
drbd_force_state(mdev, NS(conn, C_DISCONNECTING));
return;
}
} else {
/* Normally this element should be in the cache,
* since drbd_rs_begin_io() pulled it already in.
*
* But maybe an application write finished, and we set
* something outside the resync lru_cache in sync.
*/
int rs_left = drbd_bm_e_weight(mdev, enr);
if (ext->flags != 0) {
dev_warn(DEV, "changing resync lce: %d[%u;%02lx]"
" -> %d[%u;00]\n",
ext->lce.lc_number, ext->rs_left,
ext->flags, enr, rs_left);
ext->flags = 0;
}
if (ext->rs_failed) {
dev_warn(DEV, "Kicking resync_lru element enr=%u "
"out with rs_failed=%d\n",
ext->lce.lc_number, ext->rs_failed);
set_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags);
}
ext->rs_left = rs_left;
ext->rs_failed = success ? 0 : count;
lc_changed(mdev->resync, &ext->lce);
}
lc_put(mdev->resync, &ext->lce);
/* no race, we are within the al_lock! */
if (ext->rs_left == ext->rs_failed) {
ext->rs_failed = 0;
udw = kmalloc(sizeof(*udw), GFP_ATOMIC);
if (udw) {
udw->enr = ext->lce.lc_number;
udw->w.cb = w_update_odbm;
drbd_queue_work_front(&mdev->data.work, &udw->w);
} else {
dev_warn(DEV, "Could not kmalloc an udw\n");
set_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags);
}
}
} else {
dev_err(DEV, "lc_get() failed! locked=%d/%d flags=%lu\n",
mdev->resync_locked,
mdev->resync->nr_elements,
mdev->resync->flags);
}
}
/* clear the bit corresponding to the piece of storage in question:
* size byte of data starting from sector. Only clear a bits of the affected
* one ore more _aligned_ BM_BLOCK_SIZE blocks.
*
* called by worker on C_SYNC_TARGET and receiver on SyncSource.
*
*/
void __drbd_set_in_sync(struct drbd_conf *mdev, sector_t sector, int size,
const char *file, const unsigned int line)
{
/* Is called from worker and receiver context _only_ */
unsigned long sbnr, ebnr, lbnr;
unsigned long count = 0;
sector_t esector, nr_sectors;
int wake_up = 0;
unsigned long flags;
if (size <= 0 || (size & 0x1ff) != 0 || size > DRBD_MAX_SEGMENT_SIZE) {
dev_err(DEV, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
(unsigned long long)sector, size);
return;
}
nr_sectors = drbd_get_capacity(mdev->this_bdev);
esector = sector + (size >> 9) - 1;
ERR_IF(sector >= nr_sectors) return;
ERR_IF(esector >= nr_sectors) esector = (nr_sectors-1);
lbnr = BM_SECT_TO_BIT(nr_sectors-1);
/* we clear it (in sync).
* round up start sector, round down end sector. we make sure we only
* clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
if (unlikely(esector < BM_SECT_PER_BIT-1))
return;
if (unlikely(esector == (nr_sectors-1)))
ebnr = lbnr;
else
ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
if (sbnr > ebnr)
return;
/*
* ok, (capacity & 7) != 0 sometimes, but who cares...
* we count rs_{total,left} in bits, not sectors.
*/
spin_lock_irqsave(&mdev->al_lock, flags);
count = drbd_bm_clear_bits(mdev, sbnr, ebnr);
if (count) {
/* we need the lock for drbd_try_clear_on_disk_bm */
if (jiffies - mdev->rs_mark_time > HZ*10) {
/* should be rolling marks,
* but we estimate only anyways. */
if (mdev->rs_mark_left != drbd_bm_total_weight(mdev) &&
mdev->state.conn != C_PAUSED_SYNC_T &&
mdev->state.conn != C_PAUSED_SYNC_S) {
mdev->rs_mark_time = jiffies;
mdev->rs_mark_left = drbd_bm_total_weight(mdev);
}
}
if (get_ldev(mdev)) {
drbd_try_clear_on_disk_bm(mdev, sector, count, TRUE);
put_ldev(mdev);
}
/* just wake_up unconditional now, various lc_chaged(),
* lc_put() in drbd_try_clear_on_disk_bm(). */
wake_up = 1;
}
spin_unlock_irqrestore(&mdev->al_lock, flags);
if (wake_up)
wake_up(&mdev->al_wait);
}
/*
* this is intended to set one request worth of data out of sync.
* affects at least 1 bit,
* and at most 1+DRBD_MAX_SEGMENT_SIZE/BM_BLOCK_SIZE bits.
*
* called by tl_clear and drbd_send_dblock (==drbd_make_request).
* so this can be _any_ process.
*/
void __drbd_set_out_of_sync(struct drbd_conf *mdev, sector_t sector, int size,
const char *file, const unsigned int line)
{
unsigned long sbnr, ebnr, lbnr, flags;
sector_t esector, nr_sectors;
unsigned int enr, count;
struct lc_element *e;
if (size <= 0 || (size & 0x1ff) != 0 || size > DRBD_MAX_SEGMENT_SIZE) {
dev_err(DEV, "sector: %llus, size: %d\n",
(unsigned long long)sector, size);
return;
}
if (!get_ldev(mdev))
return; /* no disk, no metadata, no bitmap to set bits in */
nr_sectors = drbd_get_capacity(mdev->this_bdev);
esector = sector + (size >> 9) - 1;
ERR_IF(sector >= nr_sectors)
goto out;
ERR_IF(esector >= nr_sectors)
esector = (nr_sectors-1);
lbnr = BM_SECT_TO_BIT(nr_sectors-1);
/* we set it out of sync,
* we do not need to round anything here */
sbnr = BM_SECT_TO_BIT(sector);
ebnr = BM_SECT_TO_BIT(esector);
/* ok, (capacity & 7) != 0 sometimes, but who cares...
* we count rs_{total,left} in bits, not sectors. */
spin_lock_irqsave(&mdev->al_lock, flags);
count = drbd_bm_set_bits(mdev, sbnr, ebnr);
enr = BM_SECT_TO_EXT(sector);
e = lc_find(mdev->resync, enr);
if (e)
lc_entry(e, struct bm_extent, lce)->rs_left += count;
spin_unlock_irqrestore(&mdev->al_lock, flags);
out:
put_ldev(mdev);
}
static
struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr)
{
struct lc_element *e;
struct bm_extent *bm_ext;
int wakeup = 0;
unsigned long rs_flags;
spin_lock_irq(&mdev->al_lock);
if (mdev->resync_locked > mdev->resync->nr_elements/2) {
spin_unlock_irq(&mdev->al_lock);
return NULL;
}
e = lc_get(mdev->resync, enr);
bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
if (bm_ext) {
if (bm_ext->lce.lc_number != enr) {
bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
bm_ext->rs_failed = 0;
lc_changed(mdev->resync, &bm_ext->lce);
wakeup = 1;
}
if (bm_ext->lce.refcnt == 1)
mdev->resync_locked++;
set_bit(BME_NO_WRITES, &bm_ext->flags);
}
rs_flags = mdev->resync->flags;
spin_unlock_irq(&mdev->al_lock);
if (wakeup)
wake_up(&mdev->al_wait);
if (!bm_ext) {
if (rs_flags & LC_STARVING)
dev_warn(DEV, "Have to wait for element"
" (resync LRU too small?)\n");
BUG_ON(rs_flags & LC_DIRTY);
}
return bm_ext;
}
static int _is_in_al(struct drbd_conf *mdev, unsigned int enr)
{
struct lc_element *al_ext;
int rv = 0;
spin_lock_irq(&mdev->al_lock);
if (unlikely(enr == mdev->act_log->new_number))
rv = 1;
else {
al_ext = lc_find(mdev->act_log, enr);
if (al_ext) {
if (al_ext->refcnt)
rv = 1;
}
}
spin_unlock_irq(&mdev->al_lock);
/*
if (unlikely(rv)) {
dev_info(DEV, "Delaying sync read until app's write is done\n");
}
*/
return rv;
}
/**
* drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
* @mdev: DRBD device.
* @sector: The sector number.
*
* This functions sleeps on al_wait. Returns 1 on success, 0 if interrupted.
*/
int drbd_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
{
unsigned int enr = BM_SECT_TO_EXT(sector);
struct bm_extent *bm_ext;
int i, sig;
sig = wait_event_interruptible(mdev->al_wait,
(bm_ext = _bme_get(mdev, enr)));
if (sig)
return 0;
if (test_bit(BME_LOCKED, &bm_ext->flags))
return 1;
for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
sig = wait_event_interruptible(mdev->al_wait,
!_is_in_al(mdev, enr * AL_EXT_PER_BM_SECT + i));
if (sig) {
spin_lock_irq(&mdev->al_lock);
if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
clear_bit(BME_NO_WRITES, &bm_ext->flags);
mdev->resync_locked--;
wake_up(&mdev->al_wait);
}
spin_unlock_irq(&mdev->al_lock);
return 0;
}
}
set_bit(BME_LOCKED, &bm_ext->flags);
return 1;
}
/**
* drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
* @mdev: DRBD device.
* @sector: The sector number.
*
* Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
* tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
* if there is still application IO going on in this area.
*/
int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
{
unsigned int enr = BM_SECT_TO_EXT(sector);
const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
struct lc_element *e;
struct bm_extent *bm_ext;
int i;
spin_lock_irq(&mdev->al_lock);
if (mdev->resync_wenr != LC_FREE && mdev->resync_wenr != enr) {
/* in case you have very heavy scattered io, it may
* stall the syncer undefined if we give up the ref count
* when we try again and requeue.
*
* if we don't give up the refcount, but the next time
* we are scheduled this extent has been "synced" by new
* application writes, we'd miss the lc_put on the
* extent we keep the refcount on.
* so we remembered which extent we had to try again, and
* if the next requested one is something else, we do
* the lc_put here...
* we also have to wake_up
*/
e = lc_find(mdev->resync, mdev->resync_wenr);
bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
if (bm_ext) {
D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
clear_bit(BME_NO_WRITES, &bm_ext->flags);
mdev->resync_wenr = LC_FREE;
if (lc_put(mdev->resync, &bm_ext->lce) == 0)
mdev->resync_locked--;
wake_up(&mdev->al_wait);
} else {
dev_alert(DEV, "LOGIC BUG\n");
}
}
/* TRY. */
e = lc_try_get(mdev->resync, enr);
bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
if (bm_ext) {
if (test_bit(BME_LOCKED, &bm_ext->flags))
goto proceed;
if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
mdev->resync_locked++;
} else {
/* we did set the BME_NO_WRITES,
* but then could not set BME_LOCKED,
* so we tried again.
* drop the extra reference. */
bm_ext->lce.refcnt--;
D_ASSERT(bm_ext->lce.refcnt > 0);
}
goto check_al;
} else {
/* do we rather want to try later? */
if (mdev->resync_locked > mdev->resync->nr_elements-3)
goto try_again;
/* Do or do not. There is no try. -- Yoda */
e = lc_get(mdev->resync, enr);
bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
if (!bm_ext) {
const unsigned long rs_flags = mdev->resync->flags;
if (rs_flags & LC_STARVING)
dev_warn(DEV, "Have to wait for element"
" (resync LRU too small?)\n");
BUG_ON(rs_flags & LC_DIRTY);
goto try_again;
}
if (bm_ext->lce.lc_number != enr) {
bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
bm_ext->rs_failed = 0;
lc_changed(mdev->resync, &bm_ext->lce);
wake_up(&mdev->al_wait);
D_ASSERT(test_bit(BME_LOCKED, &bm_ext->flags) == 0);
}
set_bit(BME_NO_WRITES, &bm_ext->flags);
D_ASSERT(bm_ext->lce.refcnt == 1);
mdev->resync_locked++;
goto check_al;
}
check_al:
for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
if (unlikely(al_enr+i == mdev->act_log->new_number))
goto try_again;
if (lc_is_used(mdev->act_log, al_enr+i))
goto try_again;
}
set_bit(BME_LOCKED, &bm_ext->flags);
proceed:
mdev->resync_wenr = LC_FREE;
spin_unlock_irq(&mdev->al_lock);
return 0;
try_again:
if (bm_ext)
mdev->resync_wenr = enr;
spin_unlock_irq(&mdev->al_lock);
return -EAGAIN;
}
void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector)
{
unsigned int enr = BM_SECT_TO_EXT(sector);
struct lc_element *e;
struct bm_extent *bm_ext;
unsigned long flags;
spin_lock_irqsave(&mdev->al_lock, flags);
e = lc_find(mdev->resync, enr);
bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
if (!bm_ext) {
spin_unlock_irqrestore(&mdev->al_lock, flags);
if (__ratelimit(&drbd_ratelimit_state))
dev_err(DEV, "drbd_rs_complete_io() called, but extent not found\n");
return;
}
if (bm_ext->lce.refcnt == 0) {
spin_unlock_irqrestore(&mdev->al_lock, flags);
dev_err(DEV, "drbd_rs_complete_io(,%llu [=%u]) called, "
"but refcnt is 0!?\n",
(unsigned long long)sector, enr);
return;
}
if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
clear_bit(BME_LOCKED, &bm_ext->flags);
clear_bit(BME_NO_WRITES, &bm_ext->flags);
mdev->resync_locked--;
wake_up(&mdev->al_wait);
}
spin_unlock_irqrestore(&mdev->al_lock, flags);
}
/**
* drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
* @mdev: DRBD device.
*/
void drbd_rs_cancel_all(struct drbd_conf *mdev)
{
spin_lock_irq(&mdev->al_lock);
if (get_ldev_if_state(mdev, D_FAILED)) { /* Makes sure ->resync is there. */
lc_reset(mdev->resync);
put_ldev(mdev);
}
mdev->resync_locked = 0;
mdev->resync_wenr = LC_FREE;
spin_unlock_irq(&mdev->al_lock);
wake_up(&mdev->al_wait);
}
/**
* drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
* @mdev: DRBD device.
*
* Returns 0 upon success, -EAGAIN if at least one reference count was
* not zero.
*/
int drbd_rs_del_all(struct drbd_conf *mdev)
{
struct lc_element *e;
struct bm_extent *bm_ext;
int i;
spin_lock_irq(&mdev->al_lock);
if (get_ldev_if_state(mdev, D_FAILED)) {
/* ok, ->resync is there. */
for (i = 0; i < mdev->resync->nr_elements; i++) {
e = lc_element_by_index(mdev->resync, i);
bm_ext = lc_entry(e, struct bm_extent, lce);
if (bm_ext->lce.lc_number == LC_FREE)
continue;
if (bm_ext->lce.lc_number == mdev->resync_wenr) {
dev_info(DEV, "dropping %u in drbd_rs_del_all, apparently"
" got 'synced' by application io\n",
mdev->resync_wenr);
D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
clear_bit(BME_NO_WRITES, &bm_ext->flags);
mdev->resync_wenr = LC_FREE;
lc_put(mdev->resync, &bm_ext->lce);
}
if (bm_ext->lce.refcnt != 0) {
dev_info(DEV, "Retrying drbd_rs_del_all() later. "
"refcnt=%d\n", bm_ext->lce.refcnt);
put_ldev(mdev);
spin_unlock_irq(&mdev->al_lock);
return -EAGAIN;
}
D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
D_ASSERT(!test_bit(BME_NO_WRITES, &bm_ext->flags));
lc_del(mdev->resync, &bm_ext->lce);
}
D_ASSERT(mdev->resync->used == 0);
put_ldev(mdev);
}
spin_unlock_irq(&mdev->al_lock);
return 0;
}
/**
* drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
* @mdev: DRBD device.
* @sector: The sector number.
* @size: Size of failed IO operation, in byte.
*/
void drbd_rs_failed_io(struct drbd_conf *mdev, sector_t sector, int size)
{
/* Is called from worker and receiver context _only_ */
unsigned long sbnr, ebnr, lbnr;
unsigned long count;
sector_t esector, nr_sectors;
int wake_up = 0;
if (size <= 0 || (size & 0x1ff) != 0 || size > DRBD_MAX_SEGMENT_SIZE) {
dev_err(DEV, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
(unsigned long long)sector, size);
return;
}
nr_sectors = drbd_get_capacity(mdev->this_bdev);
esector = sector + (size >> 9) - 1;
ERR_IF(sector >= nr_sectors) return;
ERR_IF(esector >= nr_sectors) esector = (nr_sectors-1);
lbnr = BM_SECT_TO_BIT(nr_sectors-1);
/*
* round up start sector, round down end sector. we make sure we only
* handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
if (unlikely(esector < BM_SECT_PER_BIT-1))
return;
if (unlikely(esector == (nr_sectors-1)))
ebnr = lbnr;
else
ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
if (sbnr > ebnr)
return;
/*
* ok, (capacity & 7) != 0 sometimes, but who cares...
* we count rs_{total,left} in bits, not sectors.
*/
spin_lock_irq(&mdev->al_lock);
count = drbd_bm_count_bits(mdev, sbnr, ebnr);
if (count) {
mdev->rs_failed += count;
if (get_ldev(mdev)) {
drbd_try_clear_on_disk_bm(mdev, sector, count, FALSE);
put_ldev(mdev);
}
/* just wake_up unconditional now, various lc_chaged(),
* lc_put() in drbd_try_clear_on_disk_bm(). */
wake_up = 1;
}
spin_unlock_irq(&mdev->al_lock);
if (wake_up)
wake_up(&mdev->al_wait);
}
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