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/*
* raid10.c : Multiple Devices driver for Linux
*
* Copyright (C) 2000-2004 Neil Brown
*
* RAID-10 support for md.
*
* Base on code in raid1.c. See raid1.c for further copyright information.
*
*
* This program 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.
*
* You should have received a copy of the GNU General Public License
* (for example /usr/src/linux/COPYING); if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/ratelimit.h>
#include <linux/kthread.h>
#include "md.h"
#include "raid10.h"
#include "raid0.h"
#include "bitmap.h"
/*
* RAID10 provides a combination of RAID0 and RAID1 functionality.
* The layout of data is defined by
* chunk_size
* raid_disks
* near_copies (stored in low byte of layout)
* far_copies (stored in second byte of layout)
* far_offset (stored in bit 16 of layout )
* use_far_sets (stored in bit 17 of layout )
* use_far_sets_bugfixed (stored in bit 18 of layout )
*
* The data to be stored is divided into chunks using chunksize. Each device
* is divided into far_copies sections. In each section, chunks are laid out
* in a style similar to raid0, but near_copies copies of each chunk is stored
* (each on a different drive). The starting device for each section is offset
* near_copies from the starting device of the previous section. Thus there
* are (near_copies * far_copies) of each chunk, and each is on a different
* drive. near_copies and far_copies must be at least one, and their product
* is at most raid_disks.
*
* If far_offset is true, then the far_copies are handled a bit differently.
* The copies are still in different stripes, but instead of being very far
* apart on disk, there are adjacent stripes.
*
* The far and offset algorithms are handled slightly differently if
* 'use_far_sets' is true. In this case, the array's devices are grouped into
* sets that are (near_copies * far_copies) in size. The far copied stripes
* are still shifted by 'near_copies' devices, but this shifting stays confined
* to the set rather than the entire array. This is done to improve the number
* of device combinations that can fail without causing the array to fail.
* Example 'far' algorithm w/o 'use_far_sets' (each letter represents a chunk
* on a device):
* A B C D A B C D E
* ... ...
* D A B C E A B C D
* Example 'far' algorithm w/ 'use_far_sets' enabled (sets illustrated w/ []'s):
* [A B] [C D] [A B] [C D E]
* |...| |...| |...| | ... |
* [B A] [D C] [B A] [E C D]
*/
/*
* Number of guaranteed r10bios in case of extreme VM load:
*/
#define NR_RAID10_BIOS 256
/* when we get a read error on a read-only array, we redirect to another
* device without failing the first device, or trying to over-write to
* correct the read error. To keep track of bad blocks on a per-bio
* level, we store IO_BLOCKED in the appropriate 'bios' pointer
*/
#define IO_BLOCKED ((struct bio *)1)
/* When we successfully write to a known bad-block, we need to remove the
* bad-block marking which must be done from process context. So we record
* the success by setting devs[n].bio to IO_MADE_GOOD
*/
#define IO_MADE_GOOD ((struct bio *)2)
#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
/* When there are this many requests queued to be written by
* the raid10 thread, we become 'congested' to provide back-pressure
* for writeback.
*/
static int max_queued_requests = 1024;
static void allow_barrier(struct r10conf *conf);
static void lower_barrier(struct r10conf *conf);
static int _enough(struct r10conf *conf, int previous, int ignore);
static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
int *skipped);
static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
static void end_reshape_write(struct bio *bio);
static void end_reshape(struct r10conf *conf);
static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
{
struct r10conf *conf = data;
int size = offsetof(struct r10bio, devs[conf->copies]);
/* allocate a r10bio with room for raid_disks entries in the
* bios array */
return kzalloc(size, gfp_flags);
}
static void r10bio_pool_free(void *r10_bio, void *data)
{
kfree(r10_bio);
}
/* Maximum size of each resync request */
#define RESYNC_BLOCK_SIZE (64*1024)
#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
/* amount of memory to reserve for resync requests */
#define RESYNC_WINDOW (1024*1024)
/* maximum number of concurrent requests, memory permitting */
#define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
/*
* When performing a resync, we need to read and compare, so
* we need as many pages are there are copies.
* When performing a recovery, we need 2 bios, one for read,
* one for write (we recover only one drive per r10buf)
*
*/
static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
{
struct r10conf *conf = data;
struct page *page;
struct r10bio *r10_bio;
struct bio *bio;
int i, j;
int nalloc;
r10_bio = r10bio_pool_alloc(gfp_flags, conf);
if (!r10_bio)
return NULL;
if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
nalloc = conf->copies; /* resync */
else
nalloc = 2; /* recovery */
/*
* Allocate bios.
*/
for (j = nalloc ; j-- ; ) {
bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
if (!bio)
goto out_free_bio;
r10_bio->devs[j].bio = bio;
if (!conf->have_replacement)
continue;
bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
if (!bio)
goto out_free_bio;
r10_bio->devs[j].repl_bio = bio;
}
/*
* Allocate RESYNC_PAGES data pages and attach them
* where needed.
*/
for (j = 0 ; j < nalloc; j++) {
struct bio *rbio = r10_bio->devs[j].repl_bio;
bio = r10_bio->devs[j].bio;
for (i = 0; i < RESYNC_PAGES; i++) {
if (j > 0 && !test_bit(MD_RECOVERY_SYNC,
&conf->mddev->recovery)) {
/* we can share bv_page's during recovery
* and reshape */
struct bio *rbio = r10_bio->devs[0].bio;
page = rbio->bi_io_vec[i].bv_page;
get_page(page);
} else
page = alloc_page(gfp_flags);
if (unlikely(!page))
goto out_free_pages;
bio->bi_io_vec[i].bv_page = page;
if (rbio)
rbio->bi_io_vec[i].bv_page = page;
}
}
return r10_bio;
out_free_pages:
for ( ; i > 0 ; i--)
safe_put_page(bio->bi_io_vec[i-1].bv_page);
while (j--)
for (i = 0; i < RESYNC_PAGES ; i++)
safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
j = 0;
out_free_bio:
for ( ; j < nalloc; j++) {
if (r10_bio->devs[j].bio)
bio_put(r10_bio->devs[j].bio);
if (r10_bio->devs[j].repl_bio)
bio_put(r10_bio->devs[j].repl_bio);
}
r10bio_pool_free(r10_bio, conf);
return NULL;
}
static void r10buf_pool_free(void *__r10_bio, void *data)
{
int i;
struct r10conf *conf = data;
struct r10bio *r10bio = __r10_bio;
int j;
for (j=0; j < conf->copies; j++) {
struct bio *bio = r10bio->devs[j].bio;
if (bio) {
for (i = 0; i < RESYNC_PAGES; i++) {
safe_put_page(bio->bi_io_vec[i].bv_page);
bio->bi_io_vec[i].bv_page = NULL;
}
bio_put(bio);
}
bio = r10bio->devs[j].repl_bio;
if (bio)
bio_put(bio);
}
r10bio_pool_free(r10bio, conf);
}
static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
{
int i;
for (i = 0; i < conf->copies; i++) {
struct bio **bio = & r10_bio->devs[i].bio;
if (!BIO_SPECIAL(*bio))
bio_put(*bio);
*bio = NULL;
bio = &r10_bio->devs[i].repl_bio;
if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
bio_put(*bio);
*bio = NULL;
}
}
static void free_r10bio(struct r10bio *r10_bio)
{
struct r10conf *conf = r10_bio->mddev->private;
put_all_bios(conf, r10_bio);
mempool_free(r10_bio, conf->r10bio_pool);
}
static void put_buf(struct r10bio *r10_bio)
{
struct r10conf *conf = r10_bio->mddev->private;
mempool_free(r10_bio, conf->r10buf_pool);
lower_barrier(conf);
}
static void reschedule_retry(struct r10bio *r10_bio)
{
unsigned long flags;
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
spin_lock_irqsave(&conf->device_lock, flags);
list_add(&r10_bio->retry_list, &conf->retry_list);
conf->nr_queued ++;
spin_unlock_irqrestore(&conf->device_lock, flags);
/* wake up frozen array... */
wake_up(&conf->wait_barrier);
md_wakeup_thread(mddev->thread);
}
/*
* raid_end_bio_io() is called when we have finished servicing a mirrored
* operation and are ready to return a success/failure code to the buffer
* cache layer.
*/
static void raid_end_bio_io(struct r10bio *r10_bio)
{
struct bio *bio = r10_bio->master_bio;
int done;
struct r10conf *conf = r10_bio->mddev->private;
if (bio->bi_phys_segments) {
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
bio->bi_phys_segments--;
done = (bio->bi_phys_segments == 0);
spin_unlock_irqrestore(&conf->device_lock, flags);
} else
done = 1;
if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
bio->bi_error = -EIO;
if (done) {
bio_endio(bio);
/*
* Wake up any possible resync thread that waits for the device
* to go idle.
*/
allow_barrier(conf);
}
free_r10bio(r10_bio);
}
/*
* Update disk head position estimator based on IRQ completion info.
*/
static inline void update_head_pos(int slot, struct r10bio *r10_bio)
{
struct r10conf *conf = r10_bio->mddev->private;
conf->mirrors[r10_bio->devs[slot].devnum].head_position =
r10_bio->devs[slot].addr + (r10_bio->sectors);
}
/*
* Find the disk number which triggered given bio
*/
static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
struct bio *bio, int *slotp, int *replp)
{
int slot;
int repl = 0;
for (slot = 0; slot < conf->copies; slot++) {
if (r10_bio->devs[slot].bio == bio)
break;
if (r10_bio->devs[slot].repl_bio == bio) {
repl = 1;
break;
}
}
BUG_ON(slot == conf->copies);
update_head_pos(slot, r10_bio);
if (slotp)
*slotp = slot;
if (replp)
*replp = repl;
return r10_bio->devs[slot].devnum;
}
static void raid10_end_read_request(struct bio *bio)
{
int uptodate = !bio->bi_error;
struct r10bio *r10_bio = bio->bi_private;
int slot, dev;
struct md_rdev *rdev;
struct r10conf *conf = r10_bio->mddev->private;
slot = r10_bio->read_slot;
dev = r10_bio->devs[slot].devnum;
rdev = r10_bio->devs[slot].rdev;
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
update_head_pos(slot, r10_bio);
if (uptodate) {
/*
* Set R10BIO_Uptodate in our master bio, so that
* we will return a good error code to the higher
* levels even if IO on some other mirrored buffer fails.
*
* The 'master' represents the composite IO operation to
* user-side. So if something waits for IO, then it will
* wait for the 'master' bio.
*/
set_bit(R10BIO_Uptodate, &r10_bio->state);
} else {
/* If all other devices that store this block have
* failed, we want to return the error upwards rather
* than fail the last device. Here we redefine
* "uptodate" to mean "Don't want to retry"
*/
if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
rdev->raid_disk))
uptodate = 1;
}
if (uptodate) {
raid_end_bio_io(r10_bio);
rdev_dec_pending(rdev, conf->mddev);
} else {
/*
* oops, read error - keep the refcount on the rdev
*/
char b[BDEVNAME_SIZE];
printk_ratelimited(KERN_ERR
"md/raid10:%s: %s: rescheduling sector %llu\n",
mdname(conf->mddev),
bdevname(rdev->bdev, b),
(unsigned long long)r10_bio->sector);
set_bit(R10BIO_ReadError, &r10_bio->state);
reschedule_retry(r10_bio);
}
}
static void close_write(struct r10bio *r10_bio)
{
/* clear the bitmap if all writes complete successfully */
bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
r10_bio->sectors,
!test_bit(R10BIO_Degraded, &r10_bio->state),
0);
md_write_end(r10_bio->mddev);
}
static void one_write_done(struct r10bio *r10_bio)
{
if (atomic_dec_and_test(&r10_bio->remaining)) {
if (test_bit(R10BIO_WriteError, &r10_bio->state))
reschedule_retry(r10_bio);
else {
close_write(r10_bio);
if (test_bit(R10BIO_MadeGood, &r10_bio->state))
reschedule_retry(r10_bio);
else
raid_end_bio_io(r10_bio);
}
}
}
static void raid10_end_write_request(struct bio *bio)
{
struct r10bio *r10_bio = bio->bi_private;
int dev;
int dec_rdev = 1;
struct r10conf *conf = r10_bio->mddev->private;
int slot, repl;
struct md_rdev *rdev = NULL;
dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
if (repl)
rdev = conf->mirrors[dev].replacement;
if (!rdev) {
smp_rmb();
repl = 0;
rdev = conf->mirrors[dev].rdev;
}
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
if (bio->bi_error) {
if (repl)
/* Never record new bad blocks to replacement,
* just fail it.
*/
md_error(rdev->mddev, rdev);
else {
set_bit(WriteErrorSeen, &rdev->flags);
if (!test_and_set_bit(WantReplacement, &rdev->flags))
set_bit(MD_RECOVERY_NEEDED,
&rdev->mddev->recovery);
set_bit(R10BIO_WriteError, &r10_bio->state);
dec_rdev = 0;
}
} else {
/*
* Set R10BIO_Uptodate in our master bio, so that
* we will return a good error code for to the higher
* levels even if IO on some other mirrored buffer fails.
*
* The 'master' represents the composite IO operation to
* user-side. So if something waits for IO, then it will
* wait for the 'master' bio.
*/
sector_t first_bad;
int bad_sectors;
/*
* Do not set R10BIO_Uptodate if the current device is
* rebuilding or Faulty. This is because we cannot use
* such device for properly reading the data back (we could
* potentially use it, if the current write would have felt
* before rdev->recovery_offset, but for simplicity we don't
* check this here.
*/
if (test_bit(In_sync, &rdev->flags) &&
!test_bit(Faulty, &rdev->flags))
set_bit(R10BIO_Uptodate, &r10_bio->state);
/* Maybe we can clear some bad blocks. */
if (is_badblock(rdev,
r10_bio->devs[slot].addr,
r10_bio->sectors,
&first_bad, &bad_sectors)) {
bio_put(bio);
if (repl)
r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
else
r10_bio->devs[slot].bio = IO_MADE_GOOD;
dec_rdev = 0;
set_bit(R10BIO_MadeGood, &r10_bio->state);
}
}
/*
*
* Let's see if all mirrored write operations have finished
* already.
*/
one_write_done(r10_bio);
if (dec_rdev)
rdev_dec_pending(rdev, conf->mddev);
}
/*
* RAID10 layout manager
* As well as the chunksize and raid_disks count, there are two
* parameters: near_copies and far_copies.
* near_copies * far_copies must be <= raid_disks.
* Normally one of these will be 1.
* If both are 1, we get raid0.
* If near_copies == raid_disks, we get raid1.
*
* Chunks are laid out in raid0 style with near_copies copies of the
* first chunk, followed by near_copies copies of the next chunk and
* so on.
* If far_copies > 1, then after 1/far_copies of the array has been assigned
* as described above, we start again with a device offset of near_copies.
* So we effectively have another copy of the whole array further down all
* the drives, but with blocks on different drives.
* With this layout, and block is never stored twice on the one device.
*
* raid10_find_phys finds the sector offset of a given virtual sector
* on each device that it is on.
*
* raid10_find_virt does the reverse mapping, from a device and a
* sector offset to a virtual address
*/
static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
{
int n,f;
sector_t sector;
sector_t chunk;
sector_t stripe;
int dev;
int slot = 0;
int last_far_set_start, last_far_set_size;
last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
last_far_set_start *= geo->far_set_size;
last_far_set_size = geo->far_set_size;
last_far_set_size += (geo->raid_disks % geo->far_set_size);
/* now calculate first sector/dev */
chunk = r10bio->sector >> geo->chunk_shift;
sector = r10bio->sector & geo->chunk_mask;
chunk *= geo->near_copies;
stripe = chunk;
dev = sector_div(stripe, geo->raid_disks);
if (geo->far_offset)
stripe *= geo->far_copies;
sector += stripe << geo->chunk_shift;
/* and calculate all the others */
for (n = 0; n < geo->near_copies; n++) {
int d = dev;
int set;
sector_t s = sector;
r10bio->devs[slot].devnum = d;
r10bio->devs[slot].addr = s;
slot++;
for (f = 1; f < geo->far_copies; f++) {
set = d / geo->far_set_size;
d += geo->near_copies;
if ((geo->raid_disks % geo->far_set_size) &&
(d > last_far_set_start)) {
d -= last_far_set_start;
d %= last_far_set_size;
d += last_far_set_start;
} else {
d %= geo->far_set_size;
d += geo->far_set_size * set;
}
s += geo->stride;
r10bio->devs[slot].devnum = d;
r10bio->devs[slot].addr = s;
slot++;
}
dev++;
if (dev >= geo->raid_disks) {
dev = 0;
sector += (geo->chunk_mask + 1);
}
}
}
static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
{
struct geom *geo = &conf->geo;
if (conf->reshape_progress != MaxSector &&
((r10bio->sector >= conf->reshape_progress) !=
conf->mddev->reshape_backwards)) {
set_bit(R10BIO_Previous, &r10bio->state);
geo = &conf->prev;
} else
clear_bit(R10BIO_Previous, &r10bio->state);
__raid10_find_phys(geo, r10bio);
}
static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
{
sector_t offset, chunk, vchunk;
/* Never use conf->prev as this is only called during resync
* or recovery, so reshape isn't happening
*/
struct geom *geo = &conf->geo;
int far_set_start = (dev / geo->far_set_size) * geo->far_set_size;
int far_set_size = geo->far_set_size;
int last_far_set_start;
if (geo->raid_disks % geo->far_set_size) {
last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
last_far_set_start *= geo->far_set_size;
if (dev >= last_far_set_start) {
far_set_size = geo->far_set_size;
far_set_size += (geo->raid_disks % geo->far_set_size);
far_set_start = last_far_set_start;
}
}
offset = sector & geo->chunk_mask;
if (geo->far_offset) {
int fc;
chunk = sector >> geo->chunk_shift;
fc = sector_div(chunk, geo->far_copies);
dev -= fc * geo->near_copies;
if (dev < far_set_start)
dev += far_set_size;
} else {
while (sector >= geo->stride) {
sector -= geo->stride;
if (dev < (geo->near_copies + far_set_start))
dev += far_set_size - geo->near_copies;
else
dev -= geo->near_copies;
}
chunk = sector >> geo->chunk_shift;
}
vchunk = chunk * geo->raid_disks + dev;
sector_div(vchunk, geo->near_copies);
return (vchunk << geo->chunk_shift) + offset;
}
/*
* This routine returns the disk from which the requested read should
* be done. There is a per-array 'next expected sequential IO' sector
* number - if this matches on the next IO then we use the last disk.
* There is also a per-disk 'last know head position' sector that is
* maintained from IRQ contexts, both the normal and the resync IO
* completion handlers update this position correctly. If there is no
* perfect sequential match then we pick the disk whose head is closest.
*
* If there are 2 mirrors in the same 2 devices, performance degrades
* because position is mirror, not device based.
*
* The rdev for the device selected will have nr_pending incremented.
*/
/*
* FIXME: possibly should rethink readbalancing and do it differently
* depending on near_copies / far_copies geometry.
*/
static struct md_rdev *read_balance(struct r10conf *conf,
struct r10bio *r10_bio,
int *max_sectors)
{
const sector_t this_sector = r10_bio->sector;
int disk, slot;
int sectors = r10_bio->sectors;
int best_good_sectors;
sector_t new_distance, best_dist;
struct md_rdev *best_rdev, *rdev = NULL;
int do_balance;
int best_slot;
struct geom *geo = &conf->geo;
raid10_find_phys(conf, r10_bio);
rcu_read_lock();
sectors = r10_bio->sectors;
best_slot = -1;
best_rdev = NULL;
best_dist = MaxSector;
best_good_sectors = 0;
do_balance = 1;
/*
* Check if we can balance. We can balance on the whole
* device if no resync is going on (recovery is ok), or below
* the resync window. We take the first readable disk when
* above the resync window.
*/
if (conf->mddev->recovery_cp < MaxSector
&& (this_sector + sectors >= conf->next_resync))
do_balance = 0;
for (slot = 0; slot < conf->copies ; slot++) {
sector_t first_bad;
int bad_sectors;
sector_t dev_sector;
if (r10_bio->devs[slot].bio == IO_BLOCKED)
continue;
disk = r10_bio->devs[slot].devnum;
rdev = rcu_dereference(conf->mirrors[disk].replacement);
if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
rdev = rcu_dereference(conf->mirrors[disk].rdev);
if (rdev == NULL ||
test_bit(Faulty, &rdev->flags))
continue;
if (!test_bit(In_sync, &rdev->flags) &&
r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
continue;
dev_sector = r10_bio->devs[slot].addr;
if (is_badblock(rdev, dev_sector, sectors,
&first_bad, &bad_sectors)) {
if (best_dist < MaxSector)
/* Already have a better slot */
continue;
if (first_bad <= dev_sector) {
/* Cannot read here. If this is the
* 'primary' device, then we must not read
* beyond 'bad_sectors' from another device.
*/
bad_sectors -= (dev_sector - first_bad);
if (!do_balance && sectors > bad_sectors)
sectors = bad_sectors;
if (best_good_sectors > sectors)
best_good_sectors = sectors;
} else {
sector_t good_sectors =
first_bad - dev_sector;
if (good_sectors > best_good_sectors) {
best_good_sectors = good_sectors;
best_slot = slot;
best_rdev = rdev;
}
if (!do_balance)
/* Must read from here */
break;
}
continue;
} else
best_good_sectors = sectors;
if (!do_balance)
break;
/* This optimisation is debatable, and completely destroys
* sequential read speed for 'far copies' arrays. So only
* keep it for 'near' arrays, and review those later.
*/
if (geo->near_copies > 1 && !atomic_read(&rdev->nr_pending))
break;
/* for far > 1 always use the lowest address */
if (geo->far_copies > 1)
new_distance = r10_bio->devs[slot].addr;
else
new_distance = abs(r10_bio->devs[slot].addr -
conf->mirrors[disk].head_position);
if (new_distance < best_dist) {
best_dist = new_distance;
best_slot = slot;
best_rdev = rdev;
}
}
if (slot >= conf->copies) {
slot = best_slot;
rdev = best_rdev;
}
if (slot >= 0) {
atomic_inc(&rdev->nr_pending);
r10_bio->read_slot = slot;
} else
rdev = NULL;
rcu_read_unlock();
*max_sectors = best_good_sectors;
return rdev;
}
static int raid10_congested(struct mddev *mddev, int bits)
{
struct r10conf *conf = mddev->private;
int i, ret = 0;
if ((bits & (1 << WB_async_congested)) &&
conf->pending_count >= max_queued_requests)
return 1;
rcu_read_lock();
for (i = 0;
(i < conf->geo.raid_disks || i < conf->prev.raid_disks)
&& ret == 0;
i++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
if (rdev && !test_bit(Faulty, &rdev->flags)) {
struct request_queue *q = bdev_get_queue(rdev->bdev);
ret |= bdi_congested(&q->backing_dev_info, bits);
}
}
rcu_read_unlock();
return ret;
}
static void flush_pending_writes(struct r10conf *conf)
{
/* Any writes that have been queued but are awaiting
* bitmap updates get flushed here.
*/
spin_lock_irq(&conf->device_lock);
if (conf->pending_bio_list.head) {
struct bio *bio;
bio = bio_list_get(&conf->pending_bio_list);
conf->pending_count = 0;
spin_unlock_irq(&conf->device_lock);
/* flush any pending bitmap writes to disk
* before proceeding w/ I/O */
bitmap_unplug(conf->mddev->bitmap);
wake_up(&conf->wait_barrier);
while (bio) { /* submit pending writes */
struct bio *next = bio->bi_next;
bio->bi_next = NULL;
if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
!blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
/* Just ignore it */
bio_endio(bio);
else
generic_make_request(bio);
bio = next;
}
} else
spin_unlock_irq(&conf->device_lock);
}
/* Barriers....
* Sometimes we need to suspend IO while we do something else,
* either some resync/recovery, or reconfigure the array.
* To do this we raise a 'barrier'.
* The 'barrier' is a counter that can be raised multiple times
* to count how many activities are happening which preclude
* normal IO.
* We can only raise the barrier if there is no pending IO.
* i.e. if nr_pending == 0.
* We choose only to raise the barrier if no-one is waiting for the
* barrier to go down. This means that as soon as an IO request
* is ready, no other operations which require a barrier will start
* until the IO request has had a chance.
*
* So: regular IO calls 'wait_barrier'. When that returns there
* is no backgroup IO happening, It must arrange to call
* allow_barrier when it has finished its IO.
* backgroup IO calls must call raise_barrier. Once that returns
* there is no normal IO happeing. It must arrange to call
* lower_barrier when the particular background IO completes.
*/
static void raise_barrier(struct r10conf *conf, int force)
{
BUG_ON(force && !conf->barrier);
spin_lock_irq(&conf->resync_lock);
/* Wait until no block IO is waiting (unless 'force') */
wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
conf->resync_lock);
/* block any new IO from starting */
conf->barrier++;
/* Now wait for all pending IO to complete */
wait_event_lock_irq(conf->wait_barrier,
!atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH,
conf->resync_lock);
spin_unlock_irq(&conf->resync_lock);
}
static void lower_barrier(struct r10conf *conf)
{
unsigned long flags;
spin_lock_irqsave(&conf->resync_lock, flags);
conf->barrier--;
spin_unlock_irqrestore(&conf->resync_lock, flags);
wake_up(&conf->wait_barrier);
}
static void wait_barrier(struct r10conf *conf)
{
spin_lock_irq(&conf->resync_lock);
if (conf->barrier) {
conf->nr_waiting++;
/* Wait for the barrier to drop.
* However if there are already pending
* requests (preventing the barrier from
* rising completely), and the
* pre-process bio queue isn't empty,
* then don't wait, as we need to empty
* that queue to get the nr_pending
* count down.
*/
wait_event_lock_irq(conf->wait_barrier,
!conf->barrier ||
(atomic_read(&conf->nr_pending) &&
current->bio_list &&
!bio_list_empty(current->bio_list)),
conf->resync_lock);
conf->nr_waiting--;
if (!conf->nr_waiting)
wake_up(&conf->wait_barrier);
}
atomic_inc(&conf->nr_pending);
spin_unlock_irq(&conf->resync_lock);
}
static void allow_barrier(struct r10conf *conf)
{
if ((atomic_dec_and_test(&conf->nr_pending)) ||
(conf->array_freeze_pending))
wake_up(&conf->wait_barrier);
}
static void freeze_array(struct r10conf *conf, int extra)
{
/* stop syncio and normal IO and wait for everything to
* go quiet.
* We increment barrier and nr_waiting, and then
* wait until nr_pending match nr_queued+extra
* This is called in the context of one normal IO request
* that has failed. Thus any sync request that might be pending
* will be blocked by nr_pending, and we need to wait for
* pending IO requests to complete or be queued for re-try.
* Thus the number queued (nr_queued) plus this request (extra)
* must match the number of pending IOs (nr_pending) before
* we continue.
*/
spin_lock_irq(&conf->resync_lock);
conf->array_freeze_pending++;
conf->barrier++;
conf->nr_waiting++;
wait_event_lock_irq_cmd(conf->wait_barrier,
atomic_read(&conf->nr_pending) == conf->nr_queued+extra,
conf->resync_lock,
flush_pending_writes(conf));
conf->array_freeze_pending--;
spin_unlock_irq(&conf->resync_lock);
}
static void unfreeze_array(struct r10conf *conf)
{
/* reverse the effect of the freeze */
spin_lock_irq(&conf->resync_lock);
conf->barrier--;
conf->nr_waiting--;
wake_up(&conf->wait_barrier);
spin_unlock_irq(&conf->resync_lock);
}
static sector_t choose_data_offset(struct r10bio *r10_bio,
struct md_rdev *rdev)
{
if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
test_bit(R10BIO_Previous, &r10_bio->state))
return rdev->data_offset;
else
return rdev->new_data_offset;
}
struct raid10_plug_cb {
struct blk_plug_cb cb;
struct bio_list pending;
int pending_cnt;
};
static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
{
struct raid10_plug_cb *plug = container_of(cb, struct raid10_plug_cb,
cb);
struct mddev *mddev = plug->cb.data;
struct r10conf *conf = mddev->private;
struct bio *bio;
if (from_schedule || current->bio_list) {
spin_lock_irq(&conf->device_lock);
bio_list_merge(&conf->pending_bio_list, &plug->pending);
conf->pending_count += plug->pending_cnt;
spin_unlock_irq(&conf->device_lock);
wake_up(&conf->wait_barrier);
md_wakeup_thread(mddev->thread);
kfree(plug);
return;
}
/* we aren't scheduling, so we can do the write-out directly. */
bio = bio_list_get(&plug->pending);
bitmap_unplug(mddev->bitmap);
wake_up(&conf->wait_barrier);
while (bio) { /* submit pending writes */
struct bio *next = bio->bi_next;
bio->bi_next = NULL;
if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
!blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
/* Just ignore it */
bio_endio(bio);
else
generic_make_request(bio);
bio = next;
}
kfree(plug);
}
static void __make_request(struct mddev *mddev, struct bio *bio)
{
struct r10conf *conf = mddev->private;
struct r10bio *r10_bio;
struct bio *read_bio;
int i;
const int op = bio_op(bio);
const int rw = bio_data_dir(bio);
const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
const unsigned long do_fua = (bio->bi_opf & REQ_FUA);
unsigned long flags;
struct md_rdev *blocked_rdev;
struct blk_plug_cb *cb;
struct raid10_plug_cb *plug = NULL;
int sectors_handled;
int max_sectors;
int sectors;
/*
* Register the new request and wait if the reconstruction
* thread has put up a bar for new requests.
* Continue immediately if no resync is active currently.
*/
wait_barrier(conf);
sectors = bio_sectors(bio);
while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
bio->bi_iter.bi_sector < conf->reshape_progress &&
bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
/* IO spans the reshape position. Need to wait for
* reshape to pass
*/
allow_barrier(conf);
wait_event(conf->wait_barrier,
conf->reshape_progress <= bio->bi_iter.bi_sector ||
conf->reshape_progress >= bio->bi_iter.bi_sector +
sectors);
wait_barrier(conf);
}
if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
bio_data_dir(bio) == WRITE &&
(mddev->reshape_backwards
? (bio->bi_iter.bi_sector < conf->reshape_safe &&
bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
: (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
bio->bi_iter.bi_sector < conf->reshape_progress))) {
/* Need to update reshape_position in metadata */
mddev->reshape_position = conf->reshape_progress;
set_mask_bits(&mddev->flags, 0,
BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));
md_wakeup_thread(mddev->thread);
wait_event(mddev->sb_wait,
!test_bit(MD_CHANGE_PENDING, &mddev->flags));
conf->reshape_safe = mddev->reshape_position;
}
r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
r10_bio->master_bio = bio;
r10_bio->sectors = sectors;
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_iter.bi_sector;
r10_bio->state = 0;
/* We might need to issue multiple reads to different
* devices if there are bad blocks around, so we keep
* track of the number of reads in bio->bi_phys_segments.
* If this is 0, there is only one r10_bio and no locking
* will be needed when the request completes. If it is
* non-zero, then it is the number of not-completed requests.
*/
bio->bi_phys_segments = 0;
bio_clear_flag(bio, BIO_SEG_VALID);
if (rw == READ) {
/*
* read balancing logic:
*/
struct md_rdev *rdev;
int slot;
read_again:
rdev = read_balance(conf, r10_bio, &max_sectors);
if (!rdev) {
raid_end_bio_io(r10_bio);
return;
}
slot = r10_bio->read_slot;
read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
bio_trim(read_bio, r10_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
r10_bio->devs[slot].bio = read_bio;
r10_bio->devs[slot].rdev = rdev;
read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
choose_data_offset(r10_bio, rdev);
read_bio->bi_bdev = rdev->bdev;
read_bio->bi_end_io = raid10_end_read_request;
bio_set_op_attrs(read_bio, op, do_sync);
read_bio->bi_private = r10_bio;
if (max_sectors < r10_bio->sectors) {
/* Could not read all from this device, so we will
* need another r10_bio.
*/
sectors_handled = (r10_bio->sector + max_sectors
- bio->bi_iter.bi_sector);
r10_bio->sectors = max_sectors;
spin_lock_irq(&conf->device_lock);
if (bio->bi_phys_segments == 0)
bio->bi_phys_segments = 2;
else
bio->bi_phys_segments++;
spin_unlock_irq(&conf->device_lock);
/* Cannot call generic_make_request directly
* as that will be queued in __generic_make_request
* and subsequent mempool_alloc might block
* waiting for it. so hand bio over to raid10d.
*/
reschedule_retry(r10_bio);
r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
r10_bio->master_bio = bio;
r10_bio->sectors = bio_sectors(bio) - sectors_handled;
r10_bio->state = 0;
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_iter.bi_sector +
sectors_handled;
goto read_again;
} else
generic_make_request(read_bio);
return;
}
/*
* WRITE:
*/
if (conf->pending_count >= max_queued_requests) {
md_wakeup_thread(mddev->thread);
wait_event(conf->wait_barrier,
conf->pending_count < max_queued_requests);
}
/* first select target devices under rcu_lock and
* inc refcount on their rdev. Record them by setting
* bios[x] to bio
* If there are known/acknowledged bad blocks on any device
* on which we have seen a write error, we want to avoid
* writing to those blocks. This potentially requires several
* writes to write around the bad blocks. Each set of writes
* gets its own r10_bio with a set of bios attached. The number
* of r10_bios is recored in bio->bi_phys_segments just as with
* the read case.
*/
r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
raid10_find_phys(conf, r10_bio);
retry_write:
blocked_rdev = NULL;
rcu_read_lock();
max_sectors = r10_bio->sectors;
for (i = 0; i < conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
struct md_rdev *rrdev = rcu_dereference(
conf->mirrors[d].replacement);
if (rdev == rrdev)
rrdev = NULL;
if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
atomic_inc(&rdev->nr_pending);
blocked_rdev = rdev;
break;
}
if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
atomic_inc(&rrdev->nr_pending);
blocked_rdev = rrdev;
break;
}
if (rdev && (test_bit(Faulty, &rdev->flags)))
rdev = NULL;
if (rrdev && (test_bit(Faulty, &rrdev->flags)))
rrdev = NULL;
r10_bio->devs[i].bio = NULL;
r10_bio->devs[i].repl_bio = NULL;
if (!rdev && !rrdev) {
set_bit(R10BIO_Degraded, &r10_bio->state);
continue;
}
if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
sector_t first_bad;
sector_t dev_sector = r10_bio->devs[i].addr;
int bad_sectors;
int is_bad;
is_bad = is_badblock(rdev, dev_sector,
max_sectors,
&first_bad, &bad_sectors);
if (is_bad < 0) {
/* Mustn't write here until the bad block
* is acknowledged
*/
atomic_inc(&rdev->nr_pending);
set_bit(BlockedBadBlocks, &rdev->flags);
blocked_rdev = rdev;
break;
}
if (is_bad && first_bad <= dev_sector) {
/* Cannot write here at all */
bad_sectors -= (dev_sector - first_bad);
if (bad_sectors < max_sectors)
/* Mustn't write more than bad_sectors
* to other devices yet
*/
max_sectors = bad_sectors;
/* We don't set R10BIO_Degraded as that
* only applies if the disk is missing,
* so it might be re-added, and we want to
* know to recover this chunk.
* In this case the device is here, and the
* fact that this chunk is not in-sync is
* recorded in the bad block log.
*/
continue;
}
if (is_bad) {
int good_sectors = first_bad - dev_sector;
if (good_sectors < max_sectors)
max_sectors = good_sectors;
}
}
if (rdev) {
r10_bio->devs[i].bio = bio;
atomic_inc(&rdev->nr_pending);
}
if (rrdev) {
r10_bio->devs[i].repl_bio = bio;
atomic_inc(&rrdev->nr_pending);
}
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
/* Have to wait for this device to get unblocked, then retry */
int j;
int d;
for (j = 0; j < i; j++) {
if (r10_bio->devs[j].bio) {
d = r10_bio->devs[j].devnum;
rdev_dec_pending(conf->mirrors[d].rdev, mddev);
}
if (r10_bio->devs[j].repl_bio) {
struct md_rdev *rdev;
d = r10_bio->devs[j].devnum;
rdev = conf->mirrors[d].replacement;
if (!rdev) {
/* Race with remove_disk */
smp_mb();
rdev = conf->mirrors[d].rdev;
}
rdev_dec_pending(rdev, mddev);
}
}
allow_barrier(conf);
md_wait_for_blocked_rdev(blocked_rdev, mddev);
wait_barrier(conf);
goto retry_write;
}
if (max_sectors < r10_bio->sectors) {
/* We are splitting this into multiple parts, so
* we need to prepare for allocating another r10_bio.
*/
r10_bio->sectors = max_sectors;
spin_lock_irq(&conf->device_lock);
if (bio->bi_phys_segments == 0)
bio->bi_phys_segments = 2;
else
bio->bi_phys_segments++;
spin_unlock_irq(&conf->device_lock);
}
sectors_handled = r10_bio->sector + max_sectors -
bio->bi_iter.bi_sector;
atomic_set(&r10_bio->remaining, 1);
bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
for (i = 0; i < conf->copies; i++) {
struct bio *mbio;
int d = r10_bio->devs[i].devnum;
if (r10_bio->devs[i].bio) {
struct md_rdev *rdev = conf->mirrors[d].rdev;
mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
r10_bio->devs[i].bio = mbio;
mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr+
choose_data_offset(r10_bio,
rdev));
mbio->bi_bdev = rdev->bdev;
mbio->bi_end_io = raid10_end_write_request;
bio_set_op_attrs(mbio, op, do_sync | do_fua);
mbio->bi_private = r10_bio;
atomic_inc(&r10_bio->remaining);
cb = blk_check_plugged(raid10_unplug, mddev,
sizeof(*plug));
if (cb)
plug = container_of(cb, struct raid10_plug_cb,
cb);
else
plug = NULL;
spin_lock_irqsave(&conf->device_lock, flags);
if (plug) {
bio_list_add(&plug->pending, mbio);
plug->pending_cnt++;
} else {
bio_list_add(&conf->pending_bio_list, mbio);
conf->pending_count++;
}
spin_unlock_irqrestore(&conf->device_lock, flags);
if (!plug)
md_wakeup_thread(mddev->thread);
}
if (r10_bio->devs[i].repl_bio) {
struct md_rdev *rdev = conf->mirrors[d].replacement;
if (rdev == NULL) {
/* Replacement just got moved to main 'rdev' */
smp_mb();
rdev = conf->mirrors[d].rdev;
}
mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
r10_bio->devs[i].repl_bio = mbio;
mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr +
choose_data_offset(
r10_bio, rdev));
mbio->bi_bdev = rdev->bdev;
mbio->bi_end_io = raid10_end_write_request;
bio_set_op_attrs(mbio, op, do_sync | do_fua);
mbio->bi_private = r10_bio;
atomic_inc(&r10_bio->remaining);
spin_lock_irqsave(&conf->device_lock, flags);
bio_list_add(&conf->pending_bio_list, mbio);
conf->pending_count++;
spin_unlock_irqrestore(&conf->device_lock, flags);
if (!mddev_check_plugged(mddev))
md_wakeup_thread(mddev->thread);
}
}
/* Don't remove the bias on 'remaining' (one_write_done) until
* after checking if we need to go around again.
*/
if (sectors_handled < bio_sectors(bio)) {
one_write_done(r10_bio);
/* We need another r10_bio. It has already been counted
* in bio->bi_phys_segments.
*/
r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
r10_bio->master_bio = bio;
r10_bio->sectors = bio_sectors(bio) - sectors_handled;
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
r10_bio->state = 0;
goto retry_write;
}
one_write_done(r10_bio);
}
static void raid10_make_request(struct mddev *mddev, struct bio *bio)
{
struct r10conf *conf = mddev->private;
sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
int chunk_sects = chunk_mask + 1;
struct bio *split;
if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
md_flush_request(mddev, bio);
return;
}
md_write_start(mddev, bio);
do {
/*
* If this request crosses a chunk boundary, we need to split
* it.
*/
if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
bio_sectors(bio) > chunk_sects
&& (conf->geo.near_copies < conf->geo.raid_disks
|| conf->prev.near_copies <
conf->prev.raid_disks))) {
split = bio_split(bio, chunk_sects -
(bio->bi_iter.bi_sector &
(chunk_sects - 1)),
GFP_NOIO, fs_bio_set);
bio_chain(split, bio);
} else {
split = bio;
}
__make_request(mddev, split);
} while (split != bio);
/* In case raid10d snuck in to freeze_array */
wake_up(&conf->wait_barrier);
}
static void raid10_status(struct seq_file *seq, struct mddev *mddev)
{
struct r10conf *conf = mddev->private;
int i;
if (conf->geo.near_copies < conf->geo.raid_disks)
seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
if (conf->geo.near_copies > 1)
seq_printf(seq, " %d near-copies", conf->geo.near_copies);
if (conf->geo.far_copies > 1) {
if (conf->geo.far_offset)
seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
else
seq_printf(seq, " %d far-copies", conf->geo.far_copies);
if (conf->geo.far_set_size != conf->geo.raid_disks)
seq_printf(seq, " %d devices per set", conf->geo.far_set_size);
}
seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
conf->geo.raid_disks - mddev->degraded);
rcu_read_lock();
for (i = 0; i < conf->geo.raid_disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
seq_printf(seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
}
rcu_read_unlock();
seq_printf(seq, "]");
}
/* check if there are enough drives for
* every block to appear on atleast one.
* Don't consider the device numbered 'ignore'
* as we might be about to remove it.
*/
static int _enough(struct r10conf *conf, int previous, int ignore)
{
int first = 0;
int has_enough = 0;
int disks, ncopies;
if (previous) {
disks = conf->prev.raid_disks;
ncopies = conf->prev.near_copies;
} else {
disks = conf->geo.raid_disks;
ncopies = conf->geo.near_copies;
}
rcu_read_lock();
do {
int n = conf->copies;
int cnt = 0;
int this = first;
while (n--) {
struct md_rdev *rdev;
if (this != ignore &&
(rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
test_bit(In_sync, &rdev->flags))
cnt++;
this = (this+1) % disks;
}
if (cnt == 0)
goto out;
first = (first + ncopies) % disks;
} while (first != 0);
has_enough = 1;
out:
rcu_read_unlock();
return has_enough;
}
static int enough(struct r10conf *conf, int ignore)
{
/* when calling 'enough', both 'prev' and 'geo' must
* be stable.
* This is ensured if ->reconfig_mutex or ->device_lock
* is held.
*/
return _enough(conf, 0, ignore) &&
_enough(conf, 1, ignore);
}
static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
{
char b[BDEVNAME_SIZE];
struct r10conf *conf = mddev->private;
unsigned long flags;
/*
* If it is not operational, then we have already marked it as dead
* else if it is the last working disks, ignore the error, let the
* next level up know.
* else mark the drive as failed
*/
spin_lock_irqsave(&conf->device_lock, flags);
if (test_bit(In_sync, &rdev->flags)
&& !enough(conf, rdev->raid_disk)) {
/*
* Don't fail the drive, just return an IO error.
*/
spin_unlock_irqrestore(&conf->device_lock, flags);
return;
}
if (test_and_clear_bit(In_sync, &rdev->flags))
mddev->degraded++;
/*
* If recovery is running, make sure it aborts.
*/
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
set_bit(Blocked, &rdev->flags);
set_bit(Faulty, &rdev->flags);
set_mask_bits(&mddev->flags, 0,
BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));
spin_unlock_irqrestore(&conf->device_lock, flags);
printk(KERN_ALERT
"md/raid10:%s: Disk failure on %s, disabling device.\n"
"md/raid10:%s: Operation continuing on %d devices.\n",
mdname(mddev), bdevname(rdev->bdev, b),
mdname(mddev), conf->geo.raid_disks - mddev->degraded);
}
static void print_conf(struct r10conf *conf)
{
int i;
struct md_rdev *rdev;
printk(KERN_DEBUG "RAID10 conf printout:\n");
if (!conf) {
printk(KERN_DEBUG "(!conf)\n");
return;
}
printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
conf->geo.raid_disks);
/* This is only called with ->reconfix_mutex held, so
* rcu protection of rdev is not needed */
for (i = 0; i < conf->geo.raid_disks; i++) {
char b[BDEVNAME_SIZE];
rdev = conf->mirrors[i].rdev;
if (rdev)
printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
i, !test_bit(In_sync, &rdev->flags),
!test_bit(Faulty, &rdev->flags),
bdevname(rdev->bdev,b));
}
}
static void close_sync(struct r10conf *conf)
{
wait_barrier(conf);
allow_barrier(conf);
mempool_destroy(conf->r10buf_pool);
conf->r10buf_pool = NULL;
}
static int raid10_spare_active(struct mddev *mddev)
{
int i;
struct r10conf *conf = mddev->private;
struct raid10_info *tmp;
int count = 0;
unsigned long flags;
/*
* Find all non-in_sync disks within the RAID10 configuration
* and mark them in_sync
*/
for (i = 0; i < conf->geo.raid_disks; i++) {
tmp = conf->mirrors + i;
if (tmp->replacement
&& tmp->replacement->recovery_offset == MaxSector
&& !test_bit(Faulty, &tmp->replacement->flags)
&& !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
/* Replacement has just become active */
if (!tmp->rdev
|| !test_and_clear_bit(In_sync, &tmp->rdev->flags))
count++;
if (tmp->rdev) {
/* Replaced device not technically faulty,
* but we need to be sure it gets removed
* and never re-added.
*/
set_bit(Faulty, &tmp->rdev->flags);
sysfs_notify_dirent_safe(
tmp->rdev->sysfs_state);
}
sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
} else if (tmp->rdev
&& tmp->rdev->recovery_offset == MaxSector
&& !test_bit(Faulty, &tmp->rdev->flags)
&& !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
count++;
sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
}
}
spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded -= count;
spin_unlock_irqrestore(&conf->device_lock, flags);
print_conf(conf);
return count;
}
static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
{
struct r10conf *conf = mddev->private;
int err = -EEXIST;
int mirror;
int first = 0;
int last = conf->geo.raid_disks - 1;
if (mddev->recovery_cp < MaxSector)
/* only hot-add to in-sync arrays, as recovery is
* very different from resync
*/
return -EBUSY;
if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
return -EINVAL;
if (md_integrity_add_rdev(rdev, mddev))
return -ENXIO;
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;
if (rdev->saved_raid_disk >= first &&
conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
mirror = rdev->saved_raid_disk;
else
mirror = first;
for ( ; mirror <= last ; mirror++) {
struct raid10_info *p = &conf->mirrors[mirror];
if (p->recovery_disabled == mddev->recovery_disabled)
continue;
if (p->rdev) {
if (!test_bit(WantReplacement, &p->rdev->flags) ||
p->replacement != NULL)
continue;
clear_bit(In_sync, &rdev->flags);
set_bit(Replacement, &rdev->flags);
rdev->raid_disk = mirror;
err = 0;
if (mddev->gendisk)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
conf->fullsync = 1;
rcu_assign_pointer(p->replacement, rdev);
break;
}
if (mddev->gendisk)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
p->head_position = 0;
p->recovery_disabled = mddev->recovery_disabled - 1;
rdev->raid_disk = mirror;
err = 0;
if (rdev->saved_raid_disk != mirror)
conf->fullsync = 1;
rcu_assign_pointer(p->rdev, rdev);
break;
}
if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
print_conf(conf);
return err;
}
static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
{
struct r10conf *conf = mddev->private;
int err = 0;
int number = rdev->raid_disk;
struct md_rdev **rdevp;
struct raid10_info *p = conf->mirrors + number;
print_conf(conf);
if (rdev == p->rdev)
rdevp = &p->rdev;
else if (rdev == p->replacement)
rdevp = &p->replacement;
else
return 0;
if (test_bit(In_sync, &rdev->flags) ||
atomic_read(&rdev->nr_pending)) {
err = -EBUSY;
goto abort;
}
/* Only remove non-faulty devices if recovery
* is not possible.
*/
if (!test_bit(Faulty, &rdev->flags) &&
mddev->recovery_disabled != p->recovery_disabled &&
(!p->replacement || p->replacement == rdev) &&
number < conf->geo.raid_disks &&
enough(conf, -1)) {
err = -EBUSY;
goto abort;
}
*rdevp = NULL;
if (!test_bit(RemoveSynchronized, &rdev->flags)) {
synchronize_rcu();
if (atomic_read(&rdev->nr_pending)) {
/* lost the race, try later */
err = -EBUSY;
*rdevp = rdev;
goto abort;
}
}
if (p->replacement) {
/* We must have just cleared 'rdev' */
p->rdev = p->replacement;
clear_bit(Replacement, &p->replacement->flags);
smp_mb(); /* Make sure other CPUs may see both as identical
* but will never see neither -- if they are careful.
*/
p->replacement = NULL;
clear_bit(WantReplacement, &rdev->flags);
} else
/* We might have just remove the Replacement as faulty
* Clear the flag just in case
*/
clear_bit(WantReplacement, &rdev->flags);
err = md_integrity_register(mddev);
abort:
print_conf(conf);
return err;
}
static void end_sync_read(struct bio *bio)
{
struct r10bio *r10_bio = bio->bi_private;
struct r10conf *conf = r10_bio->mddev->private;
int d;
if (bio == r10_bio->master_bio) {
/* this is a reshape read */
d = r10_bio->read_slot; /* really the read dev */
} else
d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
if (!bio->bi_error)
set_bit(R10BIO_Uptodate, &r10_bio->state);
else
/* The write handler will notice the lack of
* R10BIO_Uptodate and record any errors etc
*/
atomic_add(r10_bio->sectors,
&conf->mirrors[d].rdev->corrected_errors);
/* for reconstruct, we always reschedule after a read.
* for resync, only after all reads
*/
rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
atomic_dec_and_test(&r10_bio->remaining)) {
/* we have read all the blocks,
* do the comparison in process context in raid10d
*/
reschedule_retry(r10_bio);
}
}
static void end_sync_request(struct r10bio *r10_bio)
{
struct mddev *mddev = r10_bio->mddev;
while (atomic_dec_and_test(&r10_bio->remaining)) {
if (r10_bio->master_bio == NULL) {
/* the primary of several recovery bios */
sector_t s = r10_bio->sectors;
if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
test_bit(R10BIO_WriteError, &r10_bio->state))
reschedule_retry(r10_bio);
else
put_buf(r10_bio);
md_done_sync(mddev, s, 1);
break;
} else {
struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
test_bit(R10BIO_WriteError, &r10_bio->state))
reschedule_retry(r10_bio);
else
put_buf(r10_bio);
r10_bio = r10_bio2;
}
}
}
static void end_sync_write(struct bio *bio)
{
struct r10bio *r10_bio = bio->bi_private;
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
int d;
sector_t first_bad;
int bad_sectors;
int slot;
int repl;
struct md_rdev *rdev = NULL;
d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
if (repl)
rdev = conf->mirrors[d].replacement;
else
rdev = conf->mirrors[d].rdev;
if (bio->bi_error) {
if (repl)
md_error(mddev, rdev);
else {
set_bit(WriteErrorSeen, &rdev->flags);
if (!test_and_set_bit(WantReplacement, &rdev->flags))
set_bit(MD_RECOVERY_NEEDED,
&rdev->mddev->recovery);
set_bit(R10BIO_WriteError, &r10_bio->state);
}
} else if (is_badblock(rdev,
r10_bio->devs[slot].addr,
r10_bio->sectors,
&first_bad, &bad_sectors))
set_bit(R10BIO_MadeGood, &r10_bio->state);
rdev_dec_pending(rdev, mddev);
end_sync_request(r10_bio);
}
/*
* Note: sync and recover and handled very differently for raid10
* This code is for resync.
* For resync, we read through virtual addresses and read all blocks.
* If there is any error, we schedule a write. The lowest numbered
* drive is authoritative.
* However requests come for physical address, so we need to map.
* For every physical address there are raid_disks/copies virtual addresses,
* which is always are least one, but is not necessarly an integer.
* This means that a physical address can span multiple chunks, so we may
* have to submit multiple io requests for a single sync request.
*/
/*
* We check if all blocks are in-sync and only write to blocks that
* aren't in sync
*/
static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
{
struct r10conf *conf = mddev->private;
int i, first;
struct bio *tbio, *fbio;
int vcnt;
atomic_set(&r10_bio->remaining, 1);
/* find the first device with a block */
for (i=0; i<conf->copies; i++)
if (!r10_bio->devs[i].bio->bi_error)
break;
if (i == conf->copies)
goto done;
first = i;
fbio = r10_bio->devs[i].bio;
fbio->bi_iter.bi_size = r10_bio->sectors << 9;
fbio->bi_iter.bi_idx = 0;
vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
/* now find blocks with errors */
for (i=0 ; i < conf->copies ; i++) {
int j, d;
tbio = r10_bio->devs[i].bio;
if (tbio->bi_end_io != end_sync_read)
continue;
if (i == first)
continue;
if (!r10_bio->devs[i].bio->bi_error) {
/* We know that the bi_io_vec layout is the same for
* both 'first' and 'i', so we just compare them.
* All vec entries are PAGE_SIZE;
*/
int sectors = r10_bio->sectors;
for (j = 0; j < vcnt; j++) {
int len = PAGE_SIZE;
if (sectors < (len / 512))
len = sectors * 512;
if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
page_address(tbio->bi_io_vec[j].bv_page),
len))
break;
sectors -= len/512;
}
if (j == vcnt)
continue;
atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
/* Don't fix anything. */
continue;
}
/* Ok, we need to write this bio, either to correct an
* inconsistency or to correct an unreadable block.
* First we need to fixup bv_offset, bv_len and
* bi_vecs, as the read request might have corrupted these
*/
bio_reset(tbio);
tbio->bi_vcnt = vcnt;
tbio->bi_iter.bi_size = fbio->bi_iter.bi_size;
tbio->bi_private = r10_bio;
tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
tbio->bi_end_io = end_sync_write;
bio_set_op_attrs(tbio, REQ_OP_WRITE, 0);
bio_copy_data(tbio, fbio);
d = r10_bio->devs[i].devnum;
atomic_inc(&conf->mirrors[d].rdev->nr_pending);
atomic_inc(&r10_bio->remaining);
md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
generic_make_request(tbio);
}
/* Now write out to any replacement devices
* that are active
*/
for (i = 0; i < conf->copies; i++) {
int d;
tbio = r10_bio->devs[i].repl_bio;
if (!tbio || !tbio->bi_end_io)
continue;
if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
&& r10_bio->devs[i].bio != fbio)
bio_copy_data(tbio, fbio);
d = r10_bio->devs[i].devnum;
atomic_inc(&r10_bio->remaining);
md_sync_acct(conf->mirrors[d].replacement->bdev,
bio_sectors(tbio));
generic_make_request(tbio);
}
done:
if (atomic_dec_and_test(&r10_bio->remaining)) {
md_done_sync(mddev, r10_bio->sectors, 1);
put_buf(r10_bio);
}
}
/*
* Now for the recovery code.
* Recovery happens across physical sectors.
* We recover all non-is_sync drives by finding the virtual address of
* each, and then choose a working drive that also has that virt address.
* There is a separate r10_bio for each non-in_sync drive.
* Only the first two slots are in use. The first for reading,
* The second for writing.
*
*/
static void fix_recovery_read_error(struct r10bio *r10_bio)
{
/* We got a read error during recovery.
* We repeat the read in smaller page-sized sections.
* If a read succeeds, write it to the new device or record
* a bad block if we cannot.
* If a read fails, record a bad block on both old and
* new devices.
*/
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
struct bio *bio = r10_bio->devs[0].bio;
sector_t sect = 0;
int sectors = r10_bio->sectors;
int idx = 0;
int dr = r10_bio->devs[0].devnum;
int dw = r10_bio->devs[1].devnum;
while (sectors) {
int s = sectors;
struct md_rdev *rdev;
sector_t addr;
int ok;
if (s > (PAGE_SIZE>>9))
s = PAGE_SIZE >> 9;
rdev = conf->mirrors[dr].rdev;
addr = r10_bio->devs[0].addr + sect,
ok = sync_page_io(rdev,
addr,
s << 9,
bio->bi_io_vec[idx].bv_page,
REQ_OP_READ, 0, false);
if (ok) {
rdev = conf->mirrors[dw].rdev;
addr = r10_bio->devs[1].addr + sect;
ok = sync_page_io(rdev,
addr,
s << 9,
bio->bi_io_vec[idx].bv_page,
REQ_OP_WRITE, 0, false);
if (!ok) {
set_bit(WriteErrorSeen, &rdev->flags);
if (!test_and_set_bit(WantReplacement,
&rdev->flags))
set_bit(MD_RECOVERY_NEEDED,
&rdev->mddev->recovery);
}
}
if (!ok) {
/* We don't worry if we cannot set a bad block -
* it really is bad so there is no loss in not
* recording it yet
*/
rdev_set_badblocks(rdev, addr, s, 0);
if (rdev != conf->mirrors[dw].rdev) {
/* need bad block on destination too */
struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
addr = r10_bio->devs[1].addr + sect;
ok = rdev_set_badblocks(rdev2, addr, s, 0);
if (!ok) {
/* just abort the recovery */
printk(KERN_NOTICE
"md/raid10:%s: recovery aborted"
" due to read error\n",
mdname(mddev));
conf->mirrors[dw].recovery_disabled
= mddev->recovery_disabled;
set_bit(MD_RECOVERY_INTR,
&mddev->recovery);
break;
}
}
}
sectors -= s;
sect += s;
idx++;
}
}
static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
{
struct r10conf *conf = mddev->private;
int d;
struct bio *wbio, *wbio2;
if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
fix_recovery_read_error(r10_bio);
end_sync_request(r10_bio);
return;
}
/*
* share the pages with the first bio
* and submit the write request
*/
d = r10_bio->devs[1].devnum;
wbio = r10_bio->devs[1].bio;
wbio2 = r10_bio->devs[1].repl_bio;
/* Need to test wbio2->bi_end_io before we call
* generic_make_request as if the former is NULL,
* the latter is free to free wbio2.
*/
if (wbio2 && !wbio2->bi_end_io)
wbio2 = NULL;
if (wbio->bi_end_io) {
atomic_inc(&conf->mirrors[d].rdev->nr_pending);
md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
generic_make_request(wbio);
}
if (wbio2) {
atomic_inc(&conf->mirrors[d].replacement->nr_pending);
md_sync_acct(conf->mirrors[d].replacement->bdev,
bio_sectors(wbio2));
generic_make_request(wbio2);
}
}
/*
* Used by fix_read_error() to decay the per rdev read_errors.
* We halve the read error count for every hour that has elapsed
* since the last recorded read error.
*
*/
static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
{
long cur_time_mon;
unsigned long hours_since_last;
unsigned int read_errors = atomic_read(&rdev->read_errors);
cur_time_mon = ktime_get_seconds();
if (rdev->last_read_error == 0) {
/* first time we've seen a read error */
rdev->last_read_error = cur_time_mon;
return;
}
hours_since_last = (long)(cur_time_mon -
rdev->last_read_error) / 3600;
rdev->last_read_error = cur_time_mon;
/*
* if hours_since_last is > the number of bits in read_errors
* just set read errors to 0. We do this to avoid
* overflowing the shift of read_errors by hours_since_last.
*/
if (hours_since_last >= 8 * sizeof(read_errors))
atomic_set(&rdev->read_errors, 0);
else
atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
}
static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
int sectors, struct page *page, int rw)
{
sector_t first_bad;
int bad_sectors;
if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
&& (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
return -1;
if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
/* success */
return 1;
if (rw == WRITE) {
set_bit(WriteErrorSeen, &rdev->flags);
if (!test_and_set_bit(WantReplacement, &rdev->flags))
set_bit(MD_RECOVERY_NEEDED,
&rdev->mddev->recovery);
}
/* need to record an error - either for the block or the device */
if (!rdev_set_badblocks(rdev, sector, sectors, 0))
md_error(rdev->mddev, rdev);
return 0;
}
/*
* This is a kernel thread which:
*
* 1. Retries failed read operations on working mirrors.
* 2. Updates the raid superblock when problems encounter.
* 3. Performs writes following reads for array synchronising.
*/
static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
{
int sect = 0; /* Offset from r10_bio->sector */
int sectors = r10_bio->sectors;
struct md_rdev*rdev;
int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
int d = r10_bio->devs[r10_bio->read_slot].devnum;
/* still own a reference to this rdev, so it cannot
* have been cleared recently.
*/
rdev = conf->mirrors[d].rdev;
if (test_bit(Faulty, &rdev->flags))
/* drive has already been failed, just ignore any
more fix_read_error() attempts */
return;
check_decay_read_errors(mddev, rdev);
atomic_inc(&rdev->read_errors);
if (atomic_read(&rdev->read_errors) > max_read_errors) {
char b[BDEVNAME_SIZE];
bdevname(rdev->bdev, b);
printk(KERN_NOTICE
"md/raid10:%s: %s: Raid device exceeded "
"read_error threshold [cur %d:max %d]\n",
mdname(mddev), b,
atomic_read(&rdev->read_errors), max_read_errors);
printk(KERN_NOTICE
"md/raid10:%s: %s: Failing raid device\n",
mdname(mddev), b);
md_error(mddev, rdev);
r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
return;
}
while(sectors) {
int s = sectors;
int sl = r10_bio->read_slot;
int success = 0;
int start;
if (s > (PAGE_SIZE>>9))
s = PAGE_SIZE >> 9;
rcu_read_lock();
do {
sector_t first_bad;
int bad_sectors;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
test_bit(In_sync, &rdev->flags) &&
!test_bit(Faulty, &rdev->flags) &&
is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
&first_bad, &bad_sectors) == 0) {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
success = sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
s<<9,
conf->tmppage,
REQ_OP_READ, 0, false);
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
if (success)
break;
}
sl++;
if (sl == conf->copies)
sl = 0;
} while (!success && sl != r10_bio->read_slot);
rcu_read_unlock();
if (!success) {
/* Cannot read from anywhere, just mark the block
* as bad on the first device to discourage future
* reads.
*/
int dn = r10_bio->devs[r10_bio->read_slot].devnum;
rdev = conf->mirrors[dn].rdev;
if (!rdev_set_badblocks(
rdev,
r10_bio->devs[r10_bio->read_slot].addr
+ sect,
s, 0)) {
md_error(mddev, rdev);
r10_bio->devs[r10_bio->read_slot].bio
= IO_BLOCKED;
}
break;
}
start = sl;
/* write it back and re-read */
rcu_read_lock();
while (sl != r10_bio->read_slot) {
char b[BDEVNAME_SIZE];
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (!rdev ||
test_bit(Faulty, &rdev->flags) ||
!test_bit(In_sync, &rdev->flags))
continue;
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
if (r10_sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
s, conf->tmppage, WRITE)
== 0) {
/* Well, this device is dead */
printk(KERN_NOTICE
"md/raid10:%s: read correction "
"write failed"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
(unsigned long long)(
sect +
choose_data_offset(r10_bio,
rdev)),
bdevname(rdev->bdev, b));
printk(KERN_NOTICE "md/raid10:%s: %s: failing "
"drive\n",
mdname(mddev),
bdevname(rdev->bdev, b));
}
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
sl = start;
while (sl != r10_bio->read_slot) {
char b[BDEVNAME_SIZE];
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (!rdev ||
test_bit(Faulty, &rdev->flags) ||
!test_bit(In_sync, &rdev->flags))
continue;
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
switch (r10_sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
s, conf->tmppage,
READ)) {
case 0:
/* Well, this device is dead */
printk(KERN_NOTICE
"md/raid10:%s: unable to read back "
"corrected sectors"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
(unsigned long long)(
sect +
choose_data_offset(r10_bio, rdev)),
bdevname(rdev->bdev, b));
printk(KERN_NOTICE "md/raid10:%s: %s: failing "
"drive\n",
mdname(mddev),
bdevname(rdev->bdev, b));
break;
case 1:
printk(KERN_INFO
"md/raid10:%s: read error corrected"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
(unsigned long long)(
sect +
choose_data_offset(r10_bio, rdev)),
bdevname(rdev->bdev, b));
atomic_add(s, &rdev->corrected_errors);
}
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
rcu_read_unlock();
sectors -= s;
sect += s;
}
}
static int narrow_write_error(struct r10bio *r10_bio, int i)
{
struct bio *bio = r10_bio->master_bio;
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
/* bio has the data to be written to slot 'i' where
* we just recently had a write error.
* We repeatedly clone the bio and trim down to one block,
* then try the write. Where the write fails we record
* a bad block.
* It is conceivable that the bio doesn't exactly align with
* blocks. We must handle this.
*
* We currently own a reference to the rdev.
*/
int block_sectors;
sector_t sector;
int sectors;
int sect_to_write = r10_bio->sectors;
int ok = 1;
if (rdev->badblocks.shift < 0)
return 0;
block_sectors = roundup(1 << rdev->badblocks.shift,
bdev_logical_block_size(rdev->bdev) >> 9);
sector = r10_bio->sector;
sectors = ((r10_bio->sector + block_sectors)
& ~(sector_t)(block_sectors - 1))
- sector;
while (sect_to_write) {
struct bio *wbio;
if (sectors > sect_to_write)
sectors = sect_to_write;
/* Write at 'sector' for 'sectors' */
wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
wbio->bi_iter.bi_sector = (r10_bio->devs[i].addr+
choose_data_offset(r10_bio, rdev) +
(sector - r10_bio->sector));
wbio->bi_bdev = rdev->bdev;
bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
if (submit_bio_wait(wbio) < 0)
/* Failure! */
ok = rdev_set_badblocks(rdev, sector,
sectors, 0)
&& ok;
bio_put(wbio);
sect_to_write -= sectors;
sector += sectors;
sectors = block_sectors;
}
return ok;
}
static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
{
int slot = r10_bio->read_slot;
struct bio *bio;
struct r10conf *conf = mddev->private;
struct md_rdev *rdev = r10_bio->devs[slot].rdev;
char b[BDEVNAME_SIZE];
unsigned long do_sync;
int max_sectors;
/* we got a read error. Maybe the drive is bad. Maybe just
* the block and we can fix it.
* We freeze all other IO, and try reading the block from
* other devices. When we find one, we re-write
* and check it that fixes the read error.
* This is all done synchronously while the array is
* frozen.
*/
bio = r10_bio->devs[slot].bio;
bdevname(bio->bi_bdev, b);
bio_put(bio);
r10_bio->devs[slot].bio = NULL;
if (mddev->ro == 0) {
freeze_array(conf, 1);
fix_read_error(conf, mddev, r10_bio);
unfreeze_array(conf);
} else
r10_bio->devs[slot].bio = IO_BLOCKED;
rdev_dec_pending(rdev, mddev);
read_more:
rdev = read_balance(conf, r10_bio, &max_sectors);
if (rdev == NULL) {
printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"
" read error for block %llu\n",
mdname(mddev), b,
(unsigned long long)r10_bio->sector);
raid_end_bio_io(r10_bio);
return;
}
do_sync = (r10_bio->master_bio->bi_opf & REQ_SYNC);
slot = r10_bio->read_slot;
printk_ratelimited(
KERN_ERR
"md/raid10:%s: %s: redirecting "
"sector %llu to another mirror\n",
mdname(mddev),
bdevname(rdev->bdev, b),
(unsigned long long)r10_bio->sector);
bio = bio_clone_mddev(r10_bio->master_bio,
GFP_NOIO, mddev);
bio_trim(bio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
r10_bio->devs[slot].bio = bio;
r10_bio->devs[slot].rdev = rdev;
bio->bi_iter.bi_sector = r10_bio->devs[slot].addr
+ choose_data_offset(r10_bio, rdev);
bio->bi_bdev = rdev->bdev;
bio_set_op_attrs(bio, REQ_OP_READ, do_sync);
bio->bi_private = r10_bio;
bio->bi_end_io = raid10_end_read_request;
if (max_sectors < r10_bio->sectors) {
/* Drat - have to split this up more */
struct bio *mbio = r10_bio->master_bio;
int sectors_handled =
r10_bio->sector + max_sectors
- mbio->bi_iter.bi_sector;
r10_bio->sectors = max_sectors;
spin_lock_irq(&conf->device_lock);
if (mbio->bi_phys_segments == 0)
mbio->bi_phys_segments = 2;
else
mbio->bi_phys_segments++;
spin_unlock_irq(&conf->device_lock);
generic_make_request(bio);
r10_bio = mempool_alloc(conf->r10bio_pool,
GFP_NOIO);
r10_bio->master_bio = mbio;
r10_bio->sectors = bio_sectors(mbio) - sectors_handled;
r10_bio->state = 0;
set_bit(R10BIO_ReadError,
&r10_bio->state);
r10_bio->mddev = mddev;
r10_bio->sector = mbio->bi_iter.bi_sector
+ sectors_handled;
goto read_more;
} else
generic_make_request(bio);
}
static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
{
/* Some sort of write request has finished and it
* succeeded in writing where we thought there was a
* bad block. So forget the bad block.
* Or possibly if failed and we need to record
* a bad block.
*/
int m;
struct md_rdev *rdev;
if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
test_bit(R10BIO_IsRecover, &r10_bio->state)) {
for (m = 0; m < conf->copies; m++) {
int dev = r10_bio->devs[m].devnum;
rdev = conf->mirrors[dev].rdev;
if (r10_bio->devs[m].bio == NULL)
continue;
if (!r10_bio->devs[m].bio->bi_error) {
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors, 0);
} else {
if (!rdev_set_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors, 0))
md_error(conf->mddev, rdev);
}
rdev = conf->mirrors[dev].replacement;
if (r10_bio->devs[m].repl_bio == NULL)
continue;
if (!r10_bio->devs[m].repl_bio->bi_error) {
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors, 0);
} else {
if (!rdev_set_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors, 0))
md_error(conf->mddev, rdev);
}
}
put_buf(r10_bio);
} else {
bool fail = false;
for (m = 0; m < conf->copies; m++) {
int dev = r10_bio->devs[m].devnum;
struct bio *bio = r10_bio->devs[m].bio;
rdev = conf->mirrors[dev].rdev;
if (bio == IO_MADE_GOOD) {
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors, 0);
rdev_dec_pending(rdev, conf->mddev);
} else if (bio != NULL && bio->bi_error) {
fail = true;
if (!narrow_write_error(r10_bio, m)) {
md_error(conf->mddev, rdev);
set_bit(R10BIO_Degraded,
&r10_bio->state);
}
rdev_dec_pending(rdev, conf->mddev);
}
bio = r10_bio->devs[m].repl_bio;
rdev = conf->mirrors[dev].replacement;
if (rdev && bio == IO_MADE_GOOD) {
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors, 0);
rdev_dec_pending(rdev, conf->mddev);
}
}
if (fail) {
spin_lock_irq(&conf->device_lock);
list_add(&r10_bio->retry_list, &conf->bio_end_io_list);
conf->nr_queued++;
spin_unlock_irq(&conf->device_lock);
md_wakeup_thread(conf->mddev->thread);
} else {
if (test_bit(R10BIO_WriteError,
&r10_bio->state))
close_write(r10_bio);
raid_end_bio_io(r10_bio);
}
}
}
static void raid10d(struct md_thread *thread)
{
struct mddev *mddev = thread->mddev;
struct r10bio *r10_bio;
unsigned long flags;
struct r10conf *conf = mddev->private;
struct list_head *head = &conf->retry_list;
struct blk_plug plug;
md_check_recovery(mddev);
if (!list_empty_careful(&conf->bio_end_io_list) &&
!test_bit(MD_CHANGE_PENDING, &mddev->flags)) {
LIST_HEAD(tmp);
spin_lock_irqsave(&conf->device_lock, flags);
if (!test_bit(MD_CHANGE_PENDING, &mddev->flags)) {
while (!list_empty(&conf->bio_end_io_list)) {
list_move(conf->bio_end_io_list.prev, &tmp);
conf->nr_queued--;
}
}
spin_unlock_irqrestore(&conf->device_lock, flags);
while (!list_empty(&tmp)) {
r10_bio = list_first_entry(&tmp, struct r10bio,
retry_list);
list_del(&r10_bio->retry_list);
if (mddev->degraded)
set_bit(R10BIO_Degraded, &r10_bio->state);
if (test_bit(R10BIO_WriteError,
&r10_bio->state))
close_write(r10_bio);
raid_end_bio_io(r10_bio);
}
}
blk_start_plug(&plug);
for (;;) {
flush_pending_writes(conf);
spin_lock_irqsave(&conf->device_lock, flags);
if (list_empty(head)) {
spin_unlock_irqrestore(&conf->device_lock, flags);
break;
}
r10_bio = list_entry(head->prev, struct r10bio, retry_list);
list_del(head->prev);
conf->nr_queued--;
spin_unlock_irqrestore(&conf->device_lock, flags);
mddev = r10_bio->mddev;
conf = mddev->private;
if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
test_bit(R10BIO_WriteError, &r10_bio->state))
handle_write_completed(conf, r10_bio);
else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
reshape_request_write(mddev, r10_bio);
else if (test_bit(R10BIO_IsSync, &r10_bio->state))
sync_request_write(mddev, r10_bio);
else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
recovery_request_write(mddev, r10_bio);
else if (test_bit(R10BIO_ReadError, &r10_bio->state))
handle_read_error(mddev, r10_bio);
else {
/* just a partial read to be scheduled from a
* separate context
*/
int slot = r10_bio->read_slot;
generic_make_request(r10_bio->devs[slot].bio);
}
cond_resched();
if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
md_check_recovery(mddev);
}
blk_finish_plug(&plug);
}
static int init_resync(struct r10conf *conf)
{
int buffs;
int i;
buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
BUG_ON(conf->r10buf_pool);
conf->have_replacement = 0;
for (i = 0; i < conf->geo.raid_disks; i++)
if (conf->mirrors[i].replacement)
conf->have_replacement = 1;
conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
if (!conf->r10buf_pool)
return -ENOMEM;
conf->next_resync = 0;
return 0;
}
/*
* perform a "sync" on one "block"
*
* We need to make sure that no normal I/O request - particularly write
* requests - conflict with active sync requests.
*
* This is achieved by tracking pending requests and a 'barrier' concept
* that can be installed to exclude normal IO requests.
*
* Resync and recovery are handled very differently.
* We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
*
* For resync, we iterate over virtual addresses, read all copies,
* and update if there are differences. If only one copy is live,
* skip it.
* For recovery, we iterate over physical addresses, read a good
* value for each non-in_sync drive, and over-write.
*
* So, for recovery we may have several outstanding complex requests for a
* given address, one for each out-of-sync device. We model this by allocating
* a number of r10_bio structures, one for each out-of-sync device.
* As we setup these structures, we collect all bio's together into a list
* which we then process collectively to add pages, and then process again
* to pass to generic_make_request.
*
* The r10_bio structures are linked using a borrowed master_bio pointer.
* This link is counted in ->remaining. When the r10_bio that points to NULL
* has its remaining count decremented to 0, the whole complex operation
* is complete.
*
*/
static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
int *skipped)
{
struct r10conf *conf = mddev->private;
struct r10bio *r10_bio;
struct bio *biolist = NULL, *bio;
sector_t max_sector, nr_sectors;
int i;
int max_sync;
sector_t sync_blocks;
sector_t sectors_skipped = 0;
int chunks_skipped = 0;
sector_t chunk_mask = conf->geo.chunk_mask;
if (!conf->r10buf_pool)
if (init_resync(conf))
return 0;
/*
* Allow skipping a full rebuild for incremental assembly
* of a clean array, like RAID1 does.
*/
if (mddev->bitmap == NULL &&
mddev->recovery_cp == MaxSector &&
mddev->reshape_position == MaxSector &&
!test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
conf->fullsync == 0) {
*skipped = 1;
return mddev->dev_sectors - sector_nr;
}
skipped:
max_sector = mddev->dev_sectors;
if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
max_sector = mddev->resync_max_sectors;
if (sector_nr >= max_sector) {
/* If we aborted, we need to abort the
* sync on the 'current' bitmap chucks (there can
* be several when recovering multiple devices).
* as we may have started syncing it but not finished.
* We can find the current address in
* mddev->curr_resync, but for recovery,
* we need to convert that to several
* virtual addresses.
*/
if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
end_reshape(conf);
close_sync(conf);
return 0;
}
if (mddev->curr_resync < max_sector) { /* aborted */
if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
&sync_blocks, 1);
else for (i = 0; i < conf->geo.raid_disks; i++) {
sector_t sect =
raid10_find_virt(conf, mddev->curr_resync, i);
bitmap_end_sync(mddev->bitmap, sect,
&sync_blocks, 1);
}
} else {
/* completed sync */
if ((!mddev->bitmap || conf->fullsync)
&& conf->have_replacement
&& test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
/* Completed a full sync so the replacements
* are now fully recovered.
*/
rcu_read_lock();
for (i = 0; i < conf->geo.raid_disks; i++) {
struct md_rdev *rdev =
rcu_dereference(conf->mirrors[i].replacement);
if (rdev)
rdev->recovery_offset = MaxSector;
}
rcu_read_unlock();
}
conf->fullsync = 0;
}
bitmap_close_sync(mddev->bitmap);
close_sync(conf);
*skipped = 1;
return sectors_skipped;
}
if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
return reshape_request(mddev, sector_nr, skipped);
if (chunks_skipped >= conf->geo.raid_disks) {
/* if there has been nothing to do on any drive,
* then there is nothing to do at all..
*/
*skipped = 1;
return (max_sector - sector_nr) + sectors_skipped;
}
if (max_sector > mddev->resync_max)
max_sector = mddev->resync_max; /* Don't do IO beyond here */
/* make sure whole request will fit in a chunk - if chunks
* are meaningful
*/
if (conf->geo.near_copies < conf->geo.raid_disks &&
max_sector > (sector_nr | chunk_mask))
max_sector = (sector_nr | chunk_mask) + 1;
/*
* If there is non-resync activity waiting for a turn, then let it
* though before starting on this new sync request.
*/
if (conf->nr_waiting)
schedule_timeout_uninterruptible(1);
/* Again, very different code for resync and recovery.
* Both must result in an r10bio with a list of bios that
* have bi_end_io, bi_sector, bi_bdev set,
* and bi_private set to the r10bio.
* For recovery, we may actually create several r10bios
* with 2 bios in each, that correspond to the bios in the main one.
* In this case, the subordinate r10bios link back through a
* borrowed master_bio pointer, and the counter in the master
* includes a ref from each subordinate.
*/
/* First, we decide what to do and set ->bi_end_io
* To end_sync_read if we want to read, and
* end_sync_write if we will want to write.
*/
max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
/* recovery... the complicated one */
int j;
r10_bio = NULL;
for (i = 0 ; i < conf->geo.raid_disks; i++) {
int still_degraded;
struct r10bio *rb2;
sector_t sect;
int must_sync;
int any_working;
struct raid10_info *mirror = &conf->mirrors[i];
struct md_rdev *mrdev, *mreplace;
rcu_read_lock();
mrdev = rcu_dereference(mirror->rdev);
mreplace = rcu_dereference(mirror->replacement);
if ((mrdev == NULL ||
test_bit(Faulty, &mrdev->flags) ||
test_bit(In_sync, &mrdev->flags)) &&
(mreplace == NULL ||
test_bit(Faulty, &mreplace->flags))) {
rcu_read_unlock();
continue;
}
still_degraded = 0;
/* want to reconstruct this device */
rb2 = r10_bio;
sect = raid10_find_virt(conf, sector_nr, i);
if (sect >= mddev->resync_max_sectors) {
/* last stripe is not complete - don't
* try to recover this sector.
*/
rcu_read_unlock();
continue;
}
if (mreplace && test_bit(Faulty, &mreplace->flags))
mreplace = NULL;
/* Unless we are doing a full sync, or a replacement
* we only need to recover the block if it is set in
* the bitmap
*/
must_sync = bitmap_start_sync(mddev->bitmap, sect,
&sync_blocks, 1);
if (sync_blocks < max_sync)
max_sync = sync_blocks;
if (!must_sync &&
mreplace == NULL &&
!conf->fullsync) {
/* yep, skip the sync_blocks here, but don't assume
* that there will never be anything to do here
*/
chunks_skipped = -1;
rcu_read_unlock();
continue;
}
atomic_inc(&mrdev->nr_pending);
if (mreplace)
atomic_inc(&mreplace->nr_pending);
rcu_read_unlock();
r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
r10_bio->state = 0;
raise_barrier(conf, rb2 != NULL);
atomic_set(&r10_bio->remaining, 0);
r10_bio->master_bio = (struct bio*)rb2;
if (rb2)
atomic_inc(&rb2->remaining);
r10_bio->mddev = mddev;
set_bit(R10BIO_IsRecover, &r10_bio->state);
r10_bio->sector = sect;
raid10_find_phys(conf, r10_bio);
/* Need to check if the array will still be
* degraded
*/
rcu_read_lock();
for (j = 0; j < conf->geo.raid_disks; j++) {
struct md_rdev *rdev = rcu_dereference(
conf->mirrors[j].rdev);
if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
still_degraded = 1;
break;
}
}
must_sync = bitmap_start_sync(mddev->bitmap, sect,
&sync_blocks, still_degraded);
any_working = 0;
for (j=0; j<conf->copies;j++) {
int k;
int d = r10_bio->devs[j].devnum;
sector_t from_addr, to_addr;
struct md_rdev *rdev =
rcu_dereference(conf->mirrors[d].rdev);
sector_t sector, first_bad;
int bad_sectors;
if (!rdev ||
!test_bit(In_sync, &rdev->flags))
continue;
/* This is where we read from */
any_working = 1;
sector = r10_bio->devs[j].addr;
if (is_badblock(rdev, sector, max_sync,
&first_bad, &bad_sectors)) {
if (first_bad > sector)
max_sync = first_bad - sector;
else {
bad_sectors -= (sector
- first_bad);
if (max_sync > bad_sectors)
max_sync = bad_sectors;
continue;
}
}
bio = r10_bio->devs[0].bio;
bio_reset(bio);
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_read;
bio_set_op_attrs(bio, REQ_OP_READ, 0);
from_addr = r10_bio->devs[j].addr;
bio->bi_iter.bi_sector = from_addr +
rdev->data_offset;
bio->bi_bdev = rdev->bdev;
atomic_inc(&rdev->nr_pending);
/* and we write to 'i' (if not in_sync) */
for (k=0; k<conf->copies; k++)
if (r10_bio->devs[k].devnum == i)
break;
BUG_ON(k == conf->copies);
to_addr = r10_bio->devs[k].addr;
r10_bio->devs[0].devnum = d;
r10_bio->devs[0].addr = from_addr;
r10_bio->devs[1].devnum = i;
r10_bio->devs[1].addr = to_addr;
if (!test_bit(In_sync, &mrdev->flags)) {
bio = r10_bio->devs[1].bio;
bio_reset(bio);
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_write;
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
bio->bi_iter.bi_sector = to_addr
+ mrdev->data_offset;
bio->bi_bdev = mrdev->bdev;
atomic_inc(&r10_bio->remaining);
} else
r10_bio->devs[1].bio->bi_end_io = NULL;
/* and maybe write to replacement */
bio = r10_bio->devs[1].repl_bio;
if (bio)
bio->bi_end_io = NULL;
/* Note: if mreplace != NULL, then bio
* cannot be NULL as r10buf_pool_alloc will
* have allocated it.
* So the second test here is pointless.
* But it keeps semantic-checkers happy, and
* this comment keeps human reviewers
* happy.
*/
if (mreplace == NULL || bio == NULL ||
test_bit(Faulty, &mreplace->flags))
break;
bio_reset(bio);
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_write;
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
bio->bi_iter.bi_sector = to_addr +
mreplace->data_offset;
bio->bi_bdev = mreplace->bdev;
atomic_inc(&r10_bio->remaining);
break;
}
rcu_read_unlock();
if (j == conf->copies) {
/* Cannot recover, so abort the recovery or
* record a bad block */
if (any_working) {
/* problem is that there are bad blocks
* on other device(s)
*/
int k;
for (k = 0; k < conf->copies; k++)
if (r10_bio->devs[k].devnum == i)
break;
if (!test_bit(In_sync,
&mrdev->flags)
&& !rdev_set_badblocks(
mrdev,
r10_bio->devs[k].addr,
max_sync, 0))
any_working = 0;
if (mreplace &&
!rdev_set_badblocks(
mreplace,
r10_bio->devs[k].addr,
max_sync, 0))
any_working = 0;
}
if (!any_working) {
if (!test_and_set_bit(MD_RECOVERY_INTR,
&mddev->recovery))
printk(KERN_INFO "md/raid10:%s: insufficient "
"working devices for recovery.\n",
mdname(mddev));
mirror->recovery_disabled
= mddev->recovery_disabled;
}
put_buf(r10_bio);
if (rb2)
atomic_dec(&rb2->remaining);
r10_bio = rb2;
rdev_dec_pending(mrdev, mddev);
if (mreplace)
rdev_dec_pending(mreplace, mddev);
break;
}
rdev_dec_pending(mrdev, mddev);
if (mreplace)
rdev_dec_pending(mreplace, mddev);
}
if (biolist == NULL) {
while (r10_bio) {
struct r10bio *rb2 = r10_bio;
r10_bio = (struct r10bio*) rb2->master_bio;
rb2->master_bio = NULL;
put_buf(rb2);
}
goto giveup;
}
} else {
/* resync. Schedule a read for every block at this virt offset */
int count = 0;
bitmap_cond_end_sync(mddev->bitmap, sector_nr, 0);
if (!bitmap_start_sync(mddev->bitmap, sector_nr,
&sync_blocks, mddev->degraded) &&
!conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
&mddev->recovery)) {
/* We can skip this block */
*skipped = 1;
return sync_blocks + sectors_skipped;
}
if (sync_blocks < max_sync)
max_sync = sync_blocks;
r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
r10_bio->state = 0;
r10_bio->mddev = mddev;
atomic_set(&r10_bio->remaining, 0);
raise_barrier(conf, 0);
conf->next_resync = sector_nr;
r10_bio->master_bio = NULL;
r10_bio->sector = sector_nr;
set_bit(R10BIO_IsSync, &r10_bio->state);
raid10_find_phys(conf, r10_bio);
r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
for (i = 0; i < conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
sector_t first_bad, sector;
int bad_sectors;
struct md_rdev *rdev;
if (r10_bio->devs[i].repl_bio)
r10_bio->devs[i].repl_bio->bi_end_io = NULL;
bio = r10_bio->devs[i].bio;
bio_reset(bio);
bio->bi_error = -EIO;
rcu_read_lock();
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
rcu_read_unlock();
continue;
}
sector = r10_bio->devs[i].addr;
if (is_badblock(rdev, sector, max_sync,
&first_bad, &bad_sectors)) {
if (first_bad > sector)
max_sync = first_bad - sector;
else {
bad_sectors -= (sector - first_bad);
if (max_sync > bad_sectors)
max_sync = bad_sectors;
rcu_read_unlock();
continue;
}
}
atomic_inc(&rdev->nr_pending);
atomic_inc(&r10_bio->remaining);
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_read;
bio_set_op_attrs(bio, REQ_OP_READ, 0);
bio->bi_iter.bi_sector = sector + rdev->data_offset;
bio->bi_bdev = rdev->bdev;
count++;
rdev = rcu_dereference(conf->mirrors[d].replacement);
if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
rcu_read_unlock();
continue;
}
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
/* Need to set up for writing to the replacement */
bio = r10_bio->devs[i].repl_bio;
bio_reset(bio);
bio->bi_error = -EIO;
sector = r10_bio->devs[i].addr;
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_write;
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
bio->bi_iter.bi_sector = sector + rdev->data_offset;
bio->bi_bdev = rdev->bdev;
count++;
}
if (count < 2) {
for (i=0; i<conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
if (r10_bio->devs[i].bio->bi_end_io)
rdev_dec_pending(conf->mirrors[d].rdev,
mddev);
if (r10_bio->devs[i].repl_bio &&
r10_bio->devs[i].repl_bio->bi_end_io)
rdev_dec_pending(
conf->mirrors[d].replacement,
mddev);
}
put_buf(r10_bio);
biolist = NULL;
goto giveup;
}
}
nr_sectors = 0;
if (sector_nr + max_sync < max_sector)
max_sector = sector_nr + max_sync;
do {
struct page *page;
int len = PAGE_SIZE;
if (sector_nr + (len>>9) > max_sector)
len = (max_sector - sector_nr) << 9;
if (len == 0)
break;
for (bio= biolist ; bio ; bio=bio->bi_next) {
struct bio *bio2;
page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
if (bio_add_page(bio, page, len, 0))
continue;
/* stop here */
bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
for (bio2 = biolist;
bio2 && bio2 != bio;
bio2 = bio2->bi_next) {
/* remove last page from this bio */
bio2->bi_vcnt--;
bio2->bi_iter.bi_size -= len;
bio_clear_flag(bio2, BIO_SEG_VALID);
}
goto bio_full;
}
nr_sectors += len>>9;
sector_nr += len>>9;
} while (biolist->bi_vcnt < RESYNC_PAGES);
bio_full:
r10_bio->sectors = nr_sectors;
while (biolist) {
bio = biolist;
biolist = biolist->bi_next;
bio->bi_next = NULL;
r10_bio = bio->bi_private;
r10_bio->sectors = nr_sectors;
if (bio->bi_end_io == end_sync_read) {
md_sync_acct(bio->bi_bdev, nr_sectors);
bio->bi_error = 0;
generic_make_request(bio);
}
}
if (sectors_skipped)
/* pretend they weren't skipped, it makes
* no important difference in this case
*/
md_done_sync(mddev, sectors_skipped, 1);
return sectors_skipped + nr_sectors;
giveup:
/* There is nowhere to write, so all non-sync
* drives must be failed or in resync, all drives
* have a bad block, so try the next chunk...
*/
if (sector_nr + max_sync < max_sector)
max_sector = sector_nr + max_sync;
sectors_skipped += (max_sector - sector_nr);
chunks_skipped ++;
sector_nr = max_sector;
goto skipped;
}
static sector_t
raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
{
sector_t size;
struct r10conf *conf = mddev->private;
if (!raid_disks)
raid_disks = min(conf->geo.raid_disks,
conf->prev.raid_disks);
if (!sectors)
sectors = conf->dev_sectors;
size = sectors >> conf->geo.chunk_shift;
sector_div(size, conf->geo.far_copies);
size = size * raid_disks;
sector_div(size, conf->geo.near_copies);
return size << conf->geo.chunk_shift;
}
static void calc_sectors(struct r10conf *conf, sector_t size)
{
/* Calculate the number of sectors-per-device that will
* actually be used, and set conf->dev_sectors and
* conf->stride
*/
size = size >> conf->geo.chunk_shift;
sector_div(size, conf->geo.far_copies);
size = size * conf->geo.raid_disks;
sector_div(size, conf->geo.near_copies);
/* 'size' is now the number of chunks in the array */
/* calculate "used chunks per device" */
size = size * conf->copies;
/* We need to round up when dividing by raid_disks to
* get the stride size.
*/
size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
conf->dev_sectors = size << conf->geo.chunk_shift;
if (conf->geo.far_offset)
conf->geo.stride = 1 << conf->geo.chunk_shift;
else {
sector_div(size, conf->geo.far_copies);
conf->geo.stride = size << conf->geo.chunk_shift;
}
}
enum geo_type {geo_new, geo_old, geo_start};
static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
{
int nc, fc, fo;
int layout, chunk, disks;
switch (new) {
case geo_old:
layout = mddev->layout;
chunk = mddev->chunk_sectors;
disks = mddev->raid_disks - mddev->delta_disks;
break;
case geo_new:
layout = mddev->new_layout;
chunk = mddev->new_chunk_sectors;
disks = mddev->raid_disks;
break;
default: /* avoid 'may be unused' warnings */
case geo_start: /* new when starting reshape - raid_disks not
* updated yet. */
layout = mddev->new_layout;
chunk = mddev->new_chunk_sectors;
disks = mddev->raid_disks + mddev->delta_disks;
break;
}
if (layout >> 19)
return -1;
if (chunk < (PAGE_SIZE >> 9) ||
!is_power_of_2(chunk))
return -2;
nc = layout & 255;
fc = (layout >> 8) & 255;
fo = layout & (1<<16);
geo->raid_disks = disks;
geo->near_copies = nc;
geo->far_copies = fc;
geo->far_offset = fo;
switch (layout >> 17) {
case 0: /* original layout. simple but not always optimal */
geo->far_set_size = disks;
break;
case 1: /* "improved" layout which was buggy. Hopefully no-one is
* actually using this, but leave code here just in case.*/
geo->far_set_size = disks/fc;
WARN(geo->far_set_size < fc,
"This RAID10 layout does not provide data safety - please backup and create new array\n");
break;
case 2: /* "improved" layout fixed to match documentation */
geo->far_set_size = fc * nc;
break;
default: /* Not a valid layout */
return -1;
}
geo->chunk_mask = chunk - 1;
geo->chunk_shift = ffz(~chunk);
return nc*fc;
}
static struct r10conf *setup_conf(struct mddev *mddev)
{
struct r10conf *conf = NULL;
int err = -EINVAL;
struct geom geo;
int copies;
copies = setup_geo(&geo, mddev, geo_new);
if (copies == -2) {
printk(KERN_ERR "md/raid10:%s: chunk size must be "
"at least PAGE_SIZE(%ld) and be a power of 2.\n",
mdname(mddev), PAGE_SIZE);
goto out;
}
if (copies < 2 || copies > mddev->raid_disks) {
printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
mdname(mddev), mddev->new_layout);
goto out;
}
err = -ENOMEM;
conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
if (!conf)
goto out;
/* FIXME calc properly */
conf->mirrors = kzalloc(sizeof(struct raid10_info)*(mddev->raid_disks +
max(0,-mddev->delta_disks)),
GFP_KERNEL);
if (!conf->mirrors)
goto out;
conf->tmppage = alloc_page(GFP_KERNEL);
if (!conf->tmppage)
goto out;
conf->geo = geo;
conf->copies = copies;
conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
r10bio_pool_free, conf);
if (!conf->r10bio_pool)
goto out;
calc_sectors(conf, mddev->dev_sectors);
if (mddev->reshape_position == MaxSector) {
conf->prev = conf->geo;
conf->reshape_progress = MaxSector;
} else {
if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
err = -EINVAL;
goto out;
}
conf->reshape_progress = mddev->reshape_position;
if (conf->prev.far_offset)
conf->prev.stride = 1 << conf->prev.chunk_shift;
else
/* far_copies must be 1 */
conf->prev.stride = conf->dev_sectors;
}
conf->reshape_safe = conf->reshape_progress;
spin_lock_init(&conf->device_lock);
INIT_LIST_HEAD(&conf->retry_list);
INIT_LIST_HEAD(&conf->bio_end_io_list);
spin_lock_init(&conf->resync_lock);
init_waitqueue_head(&conf->wait_barrier);
atomic_set(&conf->nr_pending, 0);
conf->thread = md_register_thread(raid10d, mddev, "raid10");
if (!conf->thread)
goto out;
conf->mddev = mddev;
return conf;
out:
if (err == -ENOMEM)
printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n",
mdname(mddev));
if (conf) {
mempool_destroy(conf->r10bio_pool);
kfree(conf->mirrors);
safe_put_page(conf->tmppage);
kfree(conf);
}
return ERR_PTR(err);
}
static int raid10_run(struct mddev *mddev)
{
struct r10conf *conf;
int i, disk_idx, chunk_size;
struct raid10_info *disk;
struct md_rdev *rdev;
sector_t size;
sector_t min_offset_diff = 0;
int first = 1;
bool discard_supported = false;
if (mddev->private == NULL) {
conf = setup_conf(mddev);
if (IS_ERR(conf))
return PTR_ERR(conf);
mddev->private = conf;
}
conf = mddev->private;
if (!conf)
goto out;
mddev->thread = conf->thread;
conf->thread = NULL;
chunk_size = mddev->chunk_sectors << 9;
if (mddev->queue) {
blk_queue_max_discard_sectors(mddev->queue,
mddev->chunk_sectors);
blk_queue_max_write_same_sectors(mddev->queue, 0);
blk_queue_io_min(mddev->queue, chunk_size);
if (conf->geo.raid_disks % conf->geo.near_copies)
blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
else
blk_queue_io_opt(mddev->queue, chunk_size *
(conf->geo.raid_disks / conf->geo.near_copies));
}
rdev_for_each(rdev, mddev) {
long long diff;
struct request_queue *q;
disk_idx = rdev->raid_disk;
if (disk_idx < 0)
continue;
if (disk_idx >= conf->geo.raid_disks &&
disk_idx >= conf->prev.raid_disks)
continue;
disk = conf->mirrors + disk_idx;
if (test_bit(Replacement, &rdev->flags)) {
if (disk->replacement)
goto out_free_conf;
disk->replacement = rdev;
} else {
if (disk->rdev)
goto out_free_conf;
disk->rdev = rdev;
}
q = bdev_get_queue(rdev->bdev);
diff = (rdev->new_data_offset - rdev->data_offset);
if (!mddev->reshape_backwards)
diff = -diff;
if (diff < 0)
diff = 0;
if (first || diff < min_offset_diff)
min_offset_diff = diff;
if (mddev->gendisk)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
disk->head_position = 0;
if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
discard_supported = true;
}
if (mddev->queue) {
if (discard_supported)
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
mddev->queue);
else
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
mddev->queue);
}
/* need to check that every block has at least one working mirror */
if (!enough(conf, -1)) {
printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n",
mdname(mddev));
goto out_free_conf;
}
if (conf->reshape_progress != MaxSector) {
/* must ensure that shape change is supported */
if (conf->geo.far_copies != 1 &&
conf->geo.far_offset == 0)
goto out_free_conf;
if (conf->prev.far_copies != 1 &&
conf->prev.far_offset == 0)
goto out_free_conf;
}
mddev->degraded = 0;
for (i = 0;
i < conf->geo.raid_disks
|| i < conf->prev.raid_disks;
i++) {
disk = conf->mirrors + i;
if (!disk->rdev && disk->replacement) {
/* The replacement is all we have - use it */
disk->rdev = disk->replacement;
disk->replacement = NULL;
clear_bit(Replacement, &disk->rdev->flags);
}
if (!disk->rdev ||
!test_bit(In_sync, &disk->rdev->flags)) {
disk->head_position = 0;
mddev->degraded++;
if (disk->rdev &&
disk->rdev->saved_raid_disk < 0)
conf->fullsync = 1;
}
disk->recovery_disabled = mddev->recovery_disabled - 1;
}
if (mddev->recovery_cp != MaxSector)
printk(KERN_NOTICE "md/raid10:%s: not clean"
" -- starting background reconstruction\n",
mdname(mddev));
printk(KERN_INFO
"md/raid10:%s: active with %d out of %d devices\n",
mdname(mddev), conf->geo.raid_disks - mddev->degraded,
conf->geo.raid_disks);
/*
* Ok, everything is just fine now
*/
mddev->dev_sectors = conf->dev_sectors;
size = raid10_size(mddev, 0, 0);
md_set_array_sectors(mddev, size);
mddev->resync_max_sectors = size;
if (mddev->queue) {
int stripe = conf->geo.raid_disks *
((mddev->chunk_sectors << 9) / PAGE_SIZE);
/* Calculate max read-ahead size.
* We need to readahead at least twice a whole stripe....
* maybe...
*/
stripe /= conf->geo.near_copies;
if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
}
if (md_integrity_register(mddev))
goto out_free_conf;
if (conf->reshape_progress != MaxSector) {
unsigned long before_length, after_length;
before_length = ((1 << conf->prev.chunk_shift) *
conf->prev.far_copies);
after_length = ((1 << conf->geo.chunk_shift) *
conf->geo.far_copies);
if (max(before_length, after_length) > min_offset_diff) {
/* This cannot work */
printk("md/raid10: offset difference not enough to continue reshape\n");
goto out_free_conf;
}
conf->offset_diff = min_offset_diff;
clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"reshape");
}
return 0;
out_free_conf:
md_unregister_thread(&mddev->thread);
mempool_destroy(conf->r10bio_pool);
safe_put_page(conf->tmppage);
kfree(conf->mirrors);
kfree(conf);
mddev->private = NULL;
out:
return -EIO;
}
static void raid10_free(struct mddev *mddev, void *priv)
{
struct r10conf *conf = priv;
mempool_destroy(conf->r10bio_pool);
safe_put_page(conf->tmppage);
kfree(conf->mirrors);
kfree(conf->mirrors_old);
kfree(conf->mirrors_new);
kfree(conf);
}
static void raid10_quiesce(struct mddev *mddev, int state)
{
struct r10conf *conf = mddev->private;
switch(state) {
case 1:
raise_barrier(conf, 0);
break;
case 0:
lower_barrier(conf);
break;
}
}
static int raid10_resize(struct mddev *mddev, sector_t sectors)
{
/* Resize of 'far' arrays is not supported.
* For 'near' and 'offset' arrays we can set the
* number of sectors used to be an appropriate multiple
* of the chunk size.
* For 'offset', this is far_copies*chunksize.
* For 'near' the multiplier is the LCM of
* near_copies and raid_disks.
* So if far_copies > 1 && !far_offset, fail.
* Else find LCM(raid_disks, near_copy)*far_copies and
* multiply by chunk_size. Then round to this number.
* This is mostly done by raid10_size()
*/
struct r10conf *conf = mddev->private;
sector_t oldsize, size;
if (mddev->reshape_position != MaxSector)
return -EBUSY;
if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
return -EINVAL;
oldsize = raid10_size(mddev, 0, 0);
size = raid10_size(mddev, sectors, 0);
if (mddev->external_size &&
mddev->array_sectors > size)
return -EINVAL;
if (mddev->bitmap) {
int ret = bitmap_resize(mddev->bitmap, size, 0, 0);
if (ret)
return ret;
}
md_set_array_sectors(mddev, size);
if (mddev->queue) {
set_capacity(mddev->gendisk, mddev->array_sectors);
revalidate_disk(mddev->gendisk);
}
if (sectors > mddev->dev_sectors &&
mddev->recovery_cp > oldsize) {
mddev->recovery_cp = oldsize;
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
}
calc_sectors(conf, sectors);
mddev->dev_sectors = conf->dev_sectors;
mddev->resync_max_sectors = size;
return 0;
}
static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
{
struct md_rdev *rdev;
struct r10conf *conf;
if (mddev->degraded > 0) {
printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n",
mdname(mddev));
return ERR_PTR(-EINVAL);
}
sector_div(size, devs);
/* Set new parameters */
mddev->new_level = 10;
/* new layout: far_copies = 1, near_copies = 2 */
mddev->new_layout = (1<<8) + 2;
mddev->new_chunk_sectors = mddev->chunk_sectors;
mddev->delta_disks = mddev->raid_disks;
mddev->raid_disks *= 2;
/* make sure it will be not marked as dirty */
mddev->recovery_cp = MaxSector;
mddev->dev_sectors = size;
conf = setup_conf(mddev);
if (!IS_ERR(conf)) {
rdev_for_each(rdev, mddev)
if (rdev->raid_disk >= 0) {
rdev->new_raid_disk = rdev->raid_disk * 2;
rdev->sectors = size;
}
conf->barrier = 1;
}
return conf;
}
static void *raid10_takeover(struct mddev *mddev)
{
struct r0conf *raid0_conf;
/* raid10 can take over:
* raid0 - providing it has only two drives
*/
if (mddev->level == 0) {
/* for raid0 takeover only one zone is supported */
raid0_conf = mddev->private;
if (raid0_conf->nr_strip_zones > 1) {
printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0"
" with more than one zone.\n",
mdname(mddev));
return ERR_PTR(-EINVAL);
}
return raid10_takeover_raid0(mddev,
raid0_conf->strip_zone->zone_end,
raid0_conf->strip_zone->nb_dev);
}
return ERR_PTR(-EINVAL);
}
static int raid10_check_reshape(struct mddev *mddev)
{
/* Called when there is a request to change
* - layout (to ->new_layout)
* - chunk size (to ->new_chunk_sectors)
* - raid_disks (by delta_disks)
* or when trying to restart a reshape that was ongoing.
*
* We need to validate the request and possibly allocate
* space if that might be an issue later.
*
* Currently we reject any reshape of a 'far' mode array,
* allow chunk size to change if new is generally acceptable,
* allow raid_disks to increase, and allow
* a switch between 'near' mode and 'offset' mode.
*/
struct r10conf *conf = mddev->private;
struct geom geo;
if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
return -EINVAL;
if (setup_geo(&geo, mddev, geo_start) != conf->copies)
/* mustn't change number of copies */
return -EINVAL;
if (geo.far_copies > 1 && !geo.far_offset)
/* Cannot switch to 'far' mode */
return -EINVAL;
if (mddev->array_sectors & geo.chunk_mask)
/* not factor of array size */
return -EINVAL;
if (!enough(conf, -1))
return -EINVAL;
kfree(conf->mirrors_new);
conf->mirrors_new = NULL;
if (mddev->delta_disks > 0) {
/* allocate new 'mirrors' list */
conf->mirrors_new = kzalloc(
sizeof(struct raid10_info)
*(mddev->raid_disks +
mddev->delta_disks),
GFP_KERNEL);
if (!conf->mirrors_new)
return -ENOMEM;
}
return 0;
}
/*
* Need to check if array has failed when deciding whether to:
* - start an array
* - remove non-faulty devices
* - add a spare
* - allow a reshape
* This determination is simple when no reshape is happening.
* However if there is a reshape, we need to carefully check
* both the before and after sections.
* This is because some failed devices may only affect one
* of the two sections, and some non-in_sync devices may
* be insync in the section most affected by failed devices.
*/
static int calc_degraded(struct r10conf *conf)
{
int degraded, degraded2;
int i;
rcu_read_lock();
degraded = 0;
/* 'prev' section first */
for (i = 0; i < conf->prev.raid_disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
if (!rdev || test_bit(Faulty, &rdev->flags))
degraded++;
else if (!test_bit(In_sync, &rdev->flags))
/* When we can reduce the number of devices in
* an array, this might not contribute to
* 'degraded'. It does now.
*/
degraded++;
}
rcu_read_unlock();
if (conf->geo.raid_disks == conf->prev.raid_disks)
return degraded;
rcu_read_lock();
degraded2 = 0;
for (i = 0; i < conf->geo.raid_disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
if (!rdev || test_bit(Faulty, &rdev->flags))
degraded2++;
else if (!test_bit(In_sync, &rdev->flags)) {
/* If reshape is increasing the number of devices,
* this section has already been recovered, so
* it doesn't contribute to degraded.
* else it does.
*/
if (conf->geo.raid_disks <= conf->prev.raid_disks)
degraded2++;
}
}
rcu_read_unlock();
if (degraded2 > degraded)
return degraded2;
return degraded;
}
static int raid10_start_reshape(struct mddev *mddev)
{
/* A 'reshape' has been