--- /dev/null
+/*
+ * 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 futher 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/raid/raid10.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)
+ *
+ * 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 there product is at most
+ * raid_disks.
+ */
+
+/*
+ * Number of guaranteed r10bios in case of extreme VM load:
+ */
+#define NR_RAID10_BIOS 256
+
+static void unplug_slaves(mddev_t *mddev);
+
+static void * r10bio_pool_alloc(int gfp_flags, void *data)
+{
+ conf_t *conf = data;
+ r10bio_t *r10_bio;
+ int size = offsetof(struct r10bio_s, devs[conf->copies]);
+
+ /* allocate a r10bio with room for raid_disks entries in the bios array */
+ r10_bio = kmalloc(size, gfp_flags);
+ if (r10_bio)
+ memset(r10_bio, 0, size);
+ else
+ unplug_slaves(conf->mddev);
+
+ return r10_bio;
+}
+
+static void r10bio_pool_free(void *r10_bio, void *data)
+{
+ kfree(r10_bio);
+}
+
+#define RESYNC_BLOCK_SIZE (64*1024)
+//#define RESYNC_BLOCK_SIZE PAGE_SIZE
+#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
+#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
+#define RESYNC_WINDOW (2048*1024)
+
+/*
+ * 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(int gfp_flags, void *data)
+{
+ conf_t *conf = data;
+ struct page *page;
+ r10bio_t *r10_bio;
+ struct bio *bio;
+ int i, j;
+ int nalloc;
+
+ r10_bio = r10bio_pool_alloc(gfp_flags, conf);
+ if (!r10_bio) {
+ unplug_slaves(conf->mddev);
+ return NULL;
+ }
+
+ if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
+ nalloc = conf->copies; /* resync */
+ else
+ nalloc = 2; /* recovery */
+
+ /*
+ * Allocate bios.
+ */
+ for (j = nalloc ; j-- ; ) {
+ bio = bio_alloc(gfp_flags, RESYNC_PAGES);
+ if (!bio)
+ goto out_free_bio;
+ r10_bio->devs[j].bio = bio;
+ }
+ /*
+ * Allocate RESYNC_PAGES data pages and attach them
+ * where needed.
+ */
+ for (j = 0 ; j < nalloc; j++) {
+ bio = r10_bio->devs[j].bio;
+ for (i = 0; i < RESYNC_PAGES; i++) {
+ page = alloc_page(gfp_flags);
+ if (unlikely(!page))
+ goto out_free_pages;
+
+ bio->bi_io_vec[i].bv_page = page;
+ }
+ }
+
+ return r10_bio;
+
+out_free_pages:
+ for ( ; i > 0 ; i--)
+ __free_page(bio->bi_io_vec[i-1].bv_page);
+ while (j--)
+ for (i = 0; i < RESYNC_PAGES ; i++)
+ __free_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
+ j = -1;
+out_free_bio:
+ while ( ++j < nalloc )
+ bio_put(r10_bio->devs[j].bio);
+ r10bio_pool_free(r10_bio, conf);
+ return NULL;
+}
+
+static void r10buf_pool_free(void *__r10_bio, void *data)
+{
+ int i;
+ conf_t *conf = data;
+ r10bio_t *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++) {
+ __free_page(bio->bi_io_vec[i].bv_page);
+ bio->bi_io_vec[i].bv_page = NULL;
+ }
+ bio_put(bio);
+ }
+ }
+ r10bio_pool_free(r10bio, conf);
+}
+
+static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)
+{
+ int i;
+
+ for (i = 0; i < conf->copies; i++) {
+ struct bio **bio = & r10_bio->devs[i].bio;
+ if (*bio)
+ bio_put(*bio);
+ *bio = NULL;
+ }
+}
+
+static inline void free_r10bio(r10bio_t *r10_bio)
+{
+ unsigned long flags;
+
+ conf_t *conf = mddev_to_conf(r10_bio->mddev);
+
+ /*
+ * Wake up any possible resync thread that waits for the device
+ * to go idle.
+ */
+ spin_lock_irqsave(&conf->resync_lock, flags);
+ if (!--conf->nr_pending) {
+ wake_up(&conf->wait_idle);
+ wake_up(&conf->wait_resume);
+ }
+ spin_unlock_irqrestore(&conf->resync_lock, flags);
+
+ put_all_bios(conf, r10_bio);
+ mempool_free(r10_bio, conf->r10bio_pool);
+}
+
+static inline void put_buf(r10bio_t *r10_bio)
+{
+ conf_t *conf = mddev_to_conf(r10_bio->mddev);
+ unsigned long flags;
+
+ mempool_free(r10_bio, conf->r10buf_pool);
+
+ spin_lock_irqsave(&conf->resync_lock, flags);
+ if (!conf->barrier)
+ BUG();
+ --conf->barrier;
+ wake_up(&conf->wait_resume);
+ wake_up(&conf->wait_idle);
+
+ if (!--conf->nr_pending) {
+ wake_up(&conf->wait_idle);
+ wake_up(&conf->wait_resume);
+ }
+ spin_unlock_irqrestore(&conf->resync_lock, flags);
+}
+
+static void reschedule_retry(r10bio_t *r10_bio)
+{
+ unsigned long flags;
+ mddev_t *mddev = r10_bio->mddev;
+ conf_t *conf = mddev_to_conf(mddev);
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+ list_add(&r10_bio->retry_list, &conf->retry_list);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+
+ 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(r10bio_t *r10_bio)
+{
+ struct bio *bio = r10_bio->master_bio;
+
+ bio_endio(bio, bio->bi_size,
+ test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO);
+ free_r10bio(r10_bio);
+}
+
+/*
+ * Update disk head position estimator based on IRQ completion info.
+ */
+static inline void update_head_pos(int slot, r10bio_t *r10_bio)
+{
+ conf_t *conf = mddev_to_conf(r10_bio->mddev);
+
+ conf->mirrors[r10_bio->devs[slot].devnum].head_position =
+ r10_bio->devs[slot].addr + (r10_bio->sectors);
+}
+
+static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
+{
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
+ int slot, dev;
+ conf_t *conf = mddev_to_conf(r10_bio->mddev);
+
+ if (bio->bi_size)
+ return 1;
+
+ slot = r10_bio->read_slot;
+ dev = r10_bio->devs[slot].devnum;
+ /*
+ * this branch is our 'one mirror IO has finished' event handler:
+ */
+ if (!uptodate)
+ md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
+ else
+ /*
+ * 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);
+
+ update_head_pos(slot, r10_bio);
+
+ /*
+ * we have only one bio on the read side
+ */
+ if (uptodate)
+ raid_end_bio_io(r10_bio);
+ else {
+ /*
+ * oops, read error:
+ */
+ char b[BDEVNAME_SIZE];
+ if (printk_ratelimit())
+ printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n",
+ bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector);
+ reschedule_retry(r10_bio);
+ }
+
+ rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
+ return 0;
+}
+
+static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
+{
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
+ int slot, dev;
+ conf_t *conf = mddev_to_conf(r10_bio->mddev);
+
+ if (bio->bi_size)
+ return 1;
+
+ for (slot = 0; slot < conf->copies; slot++)
+ if (r10_bio->devs[slot].bio == bio)
+ break;
+ dev = r10_bio->devs[slot].devnum;
+
+ /*
+ * this branch is our 'one mirror IO has finished' event handler:
+ */
+ if (!uptodate)
+ md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
+ 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.
+ */
+ set_bit(R10BIO_Uptodate, &r10_bio->state);
+
+ update_head_pos(slot, r10_bio);
+
+ /*
+ *
+ * Let's see if all mirrored write operations have finished
+ * already.
+ */
+ if (atomic_dec_and_test(&r10_bio->remaining)) {
+ md_write_end(r10_bio->mddev);
+ raid_end_bio_io(r10_bio);
+ }
+
+ rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
+ return 0;
+}
+
+
+/*
+ * RAID10 layout manager
+ * Aswell 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 layed 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. If a block isn't on a device,
+ * that entry in the array is set to MaxSector.
+ *
+ * raid10_find_virt does the reverse mapping, from a device and a
+ * sector offset to a virtual address
+ */
+
+static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio)
+{
+ int n,f;
+ sector_t sector;
+ sector_t chunk;
+ sector_t stripe;
+ int dev;
+
+ int slot = 0;
+
+ /* now calculate first sector/dev */
+ chunk = r10bio->sector >> conf->chunk_shift;
+ sector = r10bio->sector & conf->chunk_mask;
+
+ chunk *= conf->near_copies;
+ stripe = chunk;
+ dev = sector_div(stripe, conf->raid_disks);
+
+ sector += stripe << conf->chunk_shift;
+
+ /* and calculate all the others */
+ for (n=0; n < conf->near_copies; n++) {
+ int d = dev;
+ sector_t s = sector;
+ r10bio->devs[slot].addr = sector;
+ r10bio->devs[slot].devnum = d;
+ slot++;
+
+ for (f = 1; f < conf->far_copies; f++) {
+ d += conf->near_copies;
+ if (d >= conf->raid_disks)
+ d -= conf->raid_disks;
+ s += conf->stride;
+ r10bio->devs[slot].devnum = d;
+ r10bio->devs[slot].addr = s;
+ slot++;
+ }
+ dev++;
+ if (dev >= conf->raid_disks) {
+ dev = 0;
+ sector += (conf->chunk_mask + 1);
+ }
+ }
+ BUG_ON(slot != conf->copies);
+}
+
+static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
+{
+ sector_t offset, chunk, vchunk;
+
+ while (sector > conf->stride) {
+ sector -= conf->stride;
+ if (dev < conf->near_copies)
+ dev += conf->raid_disks - conf->near_copies;
+ else
+ dev -= conf->near_copies;
+ }
+
+ offset = sector & conf->chunk_mask;
+ chunk = sector >> conf->chunk_shift;
+ vchunk = chunk * conf->raid_disks + dev;
+ sector_div(vchunk, conf->near_copies);
+ return (vchunk << conf->chunk_shift) + offset;
+}
+
+/**
+ * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
+ * @q: request queue
+ * @bio: the buffer head that's been built up so far
+ * @biovec: the request that could be merged to it.
+ *
+ * Return amount of bytes we can accept at this offset
+ * If near_copies == raid_disk, there are no striping issues,
+ * but in that case, the function isn't called at all.
+ */
+static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio,
+ struct bio_vec *bio_vec)
+{
+ mddev_t *mddev = q->queuedata;
+ sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
+ int max;
+ unsigned int chunk_sectors = mddev->chunk_size >> 9;
+ unsigned int bio_sectors = bio->bi_size >> 9;
+
+ max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
+ if (max < 0) max = 0; /* bio_add cannot handle a negative return */
+ if (max <= bio_vec->bv_len && bio_sectors == 0)
+ return bio_vec->bv_len;
+ else
+ return max;
+}
+
+/*
+ * 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 int read_balance(conf_t *conf, r10bio_t *r10_bio)
+{
+ const unsigned long this_sector = r10_bio->sector;
+ int disk, slot, nslot;
+ const int sectors = r10_bio->sectors;
+ sector_t new_distance, current_distance;
+
+ raid10_find_phys(conf, r10_bio);
+ spin_lock_irq(&conf->device_lock);
+ /*
+ * Check if we can balance. We can balance on the whole
+ * device if no resync is going on, 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)) {
+ /* make sure that disk is operational */
+ slot = 0;
+ disk = r10_bio->devs[slot].devnum;
+
+ while (!conf->mirrors[disk].rdev ||
+ !conf->mirrors[disk].rdev->in_sync) {
+ slot++;
+ if (slot == conf->copies) {
+ slot = 0;
+ disk = -1;
+ break;
+ }
+ disk = r10_bio->devs[slot].devnum;
+ }
+ goto rb_out;
+ }
+
+
+ /* make sure the disk is operational */
+ slot = 0;
+ disk = r10_bio->devs[slot].devnum;
+ while (!conf->mirrors[disk].rdev ||
+ !conf->mirrors[disk].rdev->in_sync) {
+ slot ++;
+ if (slot == conf->copies) {
+ disk = -1;
+ goto rb_out;
+ }
+ disk = r10_bio->devs[slot].devnum;
+ }
+
+
+ current_distance = abs(this_sector - conf->mirrors[disk].head_position);
+
+ /* Find the disk whose head is closest */
+
+ for (nslot = slot; nslot < conf->copies; nslot++) {
+ int ndisk = r10_bio->devs[nslot].devnum;
+
+
+ if (!conf->mirrors[ndisk].rdev ||
+ !conf->mirrors[ndisk].rdev->in_sync)
+ continue;
+
+ if (!atomic_read(&conf->mirrors[ndisk].rdev->nr_pending)) {
+ disk = ndisk;
+ slot = nslot;
+ break;
+ }
+ new_distance = abs(r10_bio->devs[nslot].addr -
+ conf->mirrors[ndisk].head_position);
+ if (new_distance < current_distance) {
+ current_distance = new_distance;
+ disk = ndisk;
+ slot = nslot;
+ }
+ }
+
+rb_out:
+ r10_bio->read_slot = slot;
+/* conf->next_seq_sect = this_sector + sectors;*/
+
+ if (disk >= 0 && conf->mirrors[disk].rdev)
+ atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
+ spin_unlock_irq(&conf->device_lock);
+
+ return disk;
+}
+
+static void unplug_slaves(mddev_t *mddev)
+{
+ conf_t *conf = mddev_to_conf(mddev);
+ int i;
+ unsigned long flags;
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+ for (i=0; i<mddev->raid_disks; i++) {
+ mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+ if (rdev && atomic_read(&rdev->nr_pending)) {
+ request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
+
+ atomic_inc(&rdev->nr_pending);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+
+ if (r_queue->unplug_fn)
+ r_queue->unplug_fn(r_queue);
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+ atomic_dec(&rdev->nr_pending);
+ }
+ }
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+}
+static void raid10_unplug(request_queue_t *q)
+{
+ unplug_slaves(q->queuedata);
+}
+
+static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk,
+ sector_t *error_sector)
+{
+ mddev_t *mddev = q->queuedata;
+ conf_t *conf = mddev_to_conf(mddev);
+ unsigned long flags;
+ int i, ret = 0;
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+ for (i=0; i<mddev->raid_disks; i++) {
+ mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+ if (rdev && !rdev->faulty) {
+ struct block_device *bdev = rdev->bdev;
+ request_queue_t *r_queue = bdev_get_queue(bdev);
+
+ if (r_queue->issue_flush_fn) {
+ ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
+ if (ret)
+ break;
+ }
+ }
+ }
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ return ret;
+}
+
+/*
+ * Throttle resync depth, so that we can both get proper overlapping of
+ * requests, but are still able to handle normal requests quickly.
+ */
+#define RESYNC_DEPTH 32
+
+static void device_barrier(conf_t *conf, sector_t sect)
+{
+ spin_lock_irq(&conf->resync_lock);
+ wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume),
+ conf->resync_lock, unplug_slaves(conf->mddev));
+
+ if (!conf->barrier++) {
+ wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
+ conf->resync_lock, unplug_slaves(conf->mddev));
+ if (conf->nr_pending)
+ BUG();
+ }
+ wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH,
+ conf->resync_lock, unplug_slaves(conf->mddev));
+ conf->next_resync = sect;
+ spin_unlock_irq(&conf->resync_lock);
+}
+
+static int make_request(request_queue_t *q, struct bio * bio)
+{
+ mddev_t *mddev = q->queuedata;
+ conf_t *conf = mddev_to_conf(mddev);
+ mirror_info_t *mirror;
+ r10bio_t *r10_bio;
+ struct bio *read_bio;
+ int i;
+ int chunk_sects = conf->chunk_mask + 1;
+
+ /* If this request crosses a chunk boundary, we need to
+ * split it. This will only happen for 1 PAGE (or less) requests.
+ */
+ if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9)
+ > chunk_sects &&
+ conf->near_copies < conf->raid_disks)) {
+ struct bio_pair *bp;
+ /* Sanity check -- queue functions should prevent this happening */
+ if (bio->bi_vcnt != 1 ||
+ bio->bi_idx != 0)
+ goto bad_map;
+ /* This is a one page bio that upper layers
+ * refuse to split for us, so we need to split it.
+ */
+ bp = bio_split(bio, bio_split_pool,
+ chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
+ if (make_request(q, &bp->bio1))
+ generic_make_request(&bp->bio1);
+ if (make_request(q, &bp->bio2))
+ generic_make_request(&bp->bio2);
+
+ bio_pair_release(bp);
+ return 0;
+ bad_map:
+ printk("raid10_make_request bug: can't convert block across chunks"
+ " or bigger than %dk %llu %d\n", chunk_sects/2,
+ (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
+
+ bio_io_error(bio, bio->bi_size);
+ return 0;
+ }
+
+ /*
+ * 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.
+ */
+ spin_lock_irq(&conf->resync_lock);
+ wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, );
+ conf->nr_pending++;
+ spin_unlock_irq(&conf->resync_lock);
+
+ if (bio_data_dir(bio)==WRITE) {
+ disk_stat_inc(mddev->gendisk, writes);
+ disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
+ } else {
+ disk_stat_inc(mddev->gendisk, reads);
+ disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
+ }
+
+ r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
+
+ r10_bio->master_bio = bio;
+ r10_bio->sectors = bio->bi_size >> 9;
+
+ r10_bio->mddev = mddev;
+ r10_bio->sector = bio->bi_sector;
+
+ if (bio_data_dir(bio) == READ) {
+ /*
+ * read balancing logic:
+ */
+ int disk = read_balance(conf, r10_bio);
+ int slot = r10_bio->read_slot;
+ if (disk < 0) {
+ raid_end_bio_io(r10_bio);
+ return 0;
+ }
+ mirror = conf->mirrors + disk;
+
+ read_bio = bio_clone(bio, GFP_NOIO);
+
+ r10_bio->devs[slot].bio = read_bio;
+
+ read_bio->bi_sector = r10_bio->devs[slot].addr +
+ mirror->rdev->data_offset;
+ read_bio->bi_bdev = mirror->rdev->bdev;
+ read_bio->bi_end_io = raid10_end_read_request;
+ read_bio->bi_rw = READ;
+ read_bio->bi_private = r10_bio;
+
+ generic_make_request(read_bio);
+ return 0;
+ }
+
+ /*
+ * WRITE:
+ */
+ /* first select target devices under spinlock and
+ * inc refcount on their rdev. Record them by setting
+ * bios[x] to bio
+ */
+ raid10_find_phys(conf, r10_bio);
+ spin_lock_irq(&conf->device_lock);
+ for (i = 0; i < conf->copies; i++) {
+ int d = r10_bio->devs[i].devnum;
+ if (conf->mirrors[d].rdev &&
+ !conf->mirrors[d].rdev->faulty) {
+ atomic_inc(&conf->mirrors[d].rdev->nr_pending);
+ r10_bio->devs[i].bio = bio;
+ } else
+ r10_bio->devs[i].bio = NULL;
+ }
+ spin_unlock_irq(&conf->device_lock);
+
+ atomic_set(&r10_bio->remaining, 1);
+ md_write_start(mddev);
+ for (i = 0; i < conf->copies; i++) {
+ struct bio *mbio;
+ int d = r10_bio->devs[i].devnum;
+ if (!r10_bio->devs[i].bio)
+ continue;
+
+ mbio = bio_clone(bio, GFP_NOIO);
+ r10_bio->devs[i].bio = mbio;
+
+ mbio->bi_sector = r10_bio->devs[i].addr+
+ conf->mirrors[d].rdev->data_offset;
+ mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
+ mbio->bi_end_io = raid10_end_write_request;
+ mbio->bi_rw = WRITE;
+ mbio->bi_private = r10_bio;
+
+ atomic_inc(&r10_bio->remaining);
+ generic_make_request(mbio);
+ }
+
+ if (atomic_dec_and_test(&r10_bio->remaining)) {
+ md_write_end(mddev);
+ raid_end_bio_io(r10_bio);
+ }
+
+ return 0;
+}
+
+static void status(struct seq_file *seq, mddev_t *mddev)
+{
+ conf_t *conf = mddev_to_conf(mddev);
+ int i;
+
+ if (conf->near_copies < conf->raid_disks)
+ seq_printf(seq, " %dK chunks", mddev->chunk_size/1024);
+ if (conf->near_copies > 1)
+ seq_printf(seq, " %d near-copies", conf->near_copies);
+ if (conf->far_copies > 1)
+ seq_printf(seq, " %d far-copies", conf->far_copies);
+
+ seq_printf(seq, " [%d/%d] [", conf->raid_disks,
+ conf->working_disks);
+ for (i = 0; i < conf->raid_disks; i++)
+ seq_printf(seq, "%s",
+ conf->mirrors[i].rdev &&
+ conf->mirrors[i].rdev->in_sync ? "U" : "_");
+ seq_printf(seq, "]");
+}
+
+static void error(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+ char b[BDEVNAME_SIZE];
+ conf_t *conf = mddev_to_conf(mddev);
+
+ /*
+ * 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
+ */
+ if (rdev->in_sync
+ && conf->working_disks == 1)
+ /*
+ * Don't fail the drive, just return an IO error.
+ * The test should really be more sophisticated than
+ * "working_disks == 1", but it isn't critical, and
+ * can wait until we do more sophisticated "is the drive
+ * really dead" tests...
+ */
+ return;
+ if (rdev->in_sync) {
+ mddev->degraded++;
+ conf->working_disks--;
+ /*
+ * if recovery is running, make sure it aborts.
+ */
+ set_bit(MD_RECOVERY_ERR, &mddev->recovery);
+ }
+ rdev->in_sync = 0;
+ rdev->faulty = 1;
+ mddev->sb_dirty = 1;
+ printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"
+ " Operation continuing on %d devices\n",
+ bdevname(rdev->bdev,b), conf->working_disks);
+}
+
+static void print_conf(conf_t *conf)
+{
+ int i;
+ mirror_info_t *tmp;
+
+ printk("RAID10 conf printout:\n");
+ if (!conf) {
+ printk("(!conf)\n");
+ return;
+ }
+ printk(" --- wd:%d rd:%d\n", conf->working_disks,
+ conf->raid_disks);
+
+ for (i = 0; i < conf->raid_disks; i++) {
+ char b[BDEVNAME_SIZE];
+ tmp = conf->mirrors + i;
+ if (tmp->rdev)
+ printk(" disk %d, wo:%d, o:%d, dev:%s\n",
+ i, !tmp->rdev->in_sync, !tmp->rdev->faulty,
+ bdevname(tmp->rdev->bdev,b));
+ }
+}
+
+static void close_sync(conf_t *conf)
+{
+ spin_lock_irq(&conf->resync_lock);
+ wait_event_lock_irq(conf->wait_resume, !conf->barrier,
+ conf->resync_lock, unplug_slaves(conf->mddev));
+ spin_unlock_irq(&conf->resync_lock);
+
+ if (conf->barrier) BUG();
+ if (waitqueue_active(&conf->wait_idle)) BUG();
+
+ mempool_destroy(conf->r10buf_pool);
+ conf->r10buf_pool = NULL;
+}
+
+static int raid10_spare_active(mddev_t *mddev)
+{
+ int i;
+ conf_t *conf = mddev->private;
+ mirror_info_t *tmp;
+
+ spin_lock_irq(&conf->device_lock);
+ /*
+ * Find all non-in_sync disks within the RAID10 configuration
+ * and mark them in_sync
+ */
+ for (i = 0; i < conf->raid_disks; i++) {
+ tmp = conf->mirrors + i;
+ if (tmp->rdev
+ && !tmp->rdev->faulty
+ && !tmp->rdev->in_sync) {
+ conf->working_disks++;
+ mddev->degraded--;
+ tmp->rdev->in_sync = 1;
+ }
+ }
+ spin_unlock_irq(&conf->device_lock);
+
+ print_conf(conf);
+ return 0;
+}
+
+
+static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+ conf_t *conf = mddev->private;
+ int found = 0;
+ int mirror;
+ mirror_info_t *p;
+
+ if (mddev->recovery_cp < MaxSector)
+ /* only hot-add to in-sync arrays, as recovery is
+ * very different from resync
+ */
+ return 0;
+ spin_lock_irq(&conf->device_lock);
+ for (mirror=0; mirror < mddev->raid_disks; mirror++)
+ if ( !(p=conf->mirrors+mirror)->rdev) {
+ p->rdev = rdev;
+
+ blk_queue_stack_limits(mddev->queue,
+ rdev->bdev->bd_disk->queue);
+ /* as we don't honour merge_bvec_fn, we must never risk
+ * violating it, so limit ->max_sector to one PAGE, as
+ * a one page request is never in violation.
+ */
+ if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
+ mddev->queue->max_sectors > (PAGE_SIZE>>9))
+ mddev->queue->max_sectors = (PAGE_SIZE>>9);
+
+ p->head_position = 0;
+ rdev->raid_disk = mirror;
+ found = 1;
+ break;
+ }
+ spin_unlock_irq(&conf->device_lock);
+
+ print_conf(conf);
+ return found;
+}
+
+static int raid10_remove_disk(mddev_t *mddev, int number)
+{
+ conf_t *conf = mddev->private;
+ int err = 1;
+ mirror_info_t *p = conf->mirrors+ number;
+
+ print_conf(conf);
+ spin_lock_irq(&conf->device_lock);
+ if (p->rdev) {
+ if (p->rdev->in_sync ||
+ atomic_read(&p->rdev->nr_pending)) {
+ err = -EBUSY;
+ goto abort;
+ }
+ p->rdev = NULL;
+ err = 0;
+ }
+ if (err)
+ MD_BUG();
+abort:
+ spin_unlock_irq(&conf->device_lock);
+
+ print_conf(conf);
+ return err;
+}
+
+
+static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
+{
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
+ conf_t *conf = mddev_to_conf(r10_bio->mddev);
+ int i,d;
+
+ if (bio->bi_size)
+ return 1;
+
+ for (i=0; i<conf->copies; i++)
+ if (r10_bio->devs[i].bio == bio)
+ break;
+ if (i == conf->copies)
+ BUG();
+ update_head_pos(i, r10_bio);
+ d = r10_bio->devs[i].devnum;
+ if (!uptodate)
+ md_error(r10_bio->mddev,
+ conf->mirrors[d].rdev);
+
+ /* for reconstruct, we always reschedule after a read.
+ * for resync, only after all reads
+ */
+ 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);
+ }
+ rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
+ return 0;
+}
+
+static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
+{
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
+ mddev_t *mddev = r10_bio->mddev;
+ conf_t *conf = mddev_to_conf(mddev);
+ int i,d;
+
+ if (bio->bi_size)
+ return 1;
+
+ for (i = 0; i < conf->copies; i++)
+ if (r10_bio->devs[i].bio == bio)
+ break;
+ d = r10_bio->devs[i].devnum;
+
+ if (!uptodate)
+ md_error(mddev, conf->mirrors[d].rdev);
+ update_head_pos(i, r10_bio);
+
+ while (atomic_dec_and_test(&r10_bio->remaining)) {
+ if (r10_bio->master_bio == NULL) {
+ /* the primary of several recovery bios */
+ md_done_sync(mddev, r10_bio->sectors, 1);
+ put_buf(r10_bio);
+ break;
+ } else {
+ r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio;
+ put_buf(r10_bio);
+ r10_bio = r10_bio2;
+ }
+ }
+ rdev_dec_pending(conf->mirrors[d].rdev, mddev);
+ return 0;
+}
+
+/*
+ * 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(mddev_t *mddev, r10bio_t *r10_bio)
+{
+ conf_t *conf = mddev_to_conf(mddev);
+ int i, first;
+ struct bio *tbio, *fbio;
+
+ atomic_set(&r10_bio->remaining, 1);
+
+ /* find the first device with a block */
+ for (i=0; i<conf->copies; i++)
+ if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
+ break;
+
+ if (i == conf->copies)
+ goto done;
+
+ first = i;
+ fbio = r10_bio->devs[i].bio;
+
+ /* now find blocks with errors */
+ for (i=first+1 ; i < conf->copies ; i++) {
+ int vcnt, j, d;
+
+ if (!test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
+ continue;
+ /* 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;
+ */
+ tbio = r10_bio->devs[i].bio;
+ vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
+ for (j = 0; j < vcnt; j++)
+ if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
+ page_address(tbio->bi_io_vec[j].bv_page),
+ PAGE_SIZE))
+ break;
+ if (j == vcnt)
+ continue;
+ /* Ok, we need to write this bio
+ * First we need to fixup bv_offset, bv_len and
+ * bi_vecs, as the read request might have corrupted these
+ */
+ tbio->bi_vcnt = vcnt;
+ tbio->bi_size = r10_bio->sectors << 9;
+ tbio->bi_idx = 0;
+ tbio->bi_phys_segments = 0;
+ tbio->bi_hw_segments = 0;
+ tbio->bi_hw_front_size = 0;
+ tbio->bi_hw_back_size = 0;
+ tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
+ tbio->bi_flags |= 1 << BIO_UPTODATE;
+ tbio->bi_next = NULL;
+ tbio->bi_rw = WRITE;
+ tbio->bi_private = r10_bio;
+ tbio->bi_sector = r10_bio->devs[i].addr;
+
+ for (j=0; j < vcnt ; j++) {
+ tbio->bi_io_vec[j].bv_offset = 0;
+ tbio->bi_io_vec[j].bv_len = PAGE_SIZE;
+
+ memcpy(page_address(tbio->bi_io_vec[j].bv_page),
+ page_address(fbio->bi_io_vec[j].bv_page),
+ PAGE_SIZE);
+ }
+ tbio->bi_end_io = end_sync_write;
+
+ 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, tbio->bi_size >> 9);
+
+ 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 recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
+{
+ conf_t *conf = mddev_to_conf(mddev);
+ int i, d;
+ struct bio *bio, *wbio;
+
+
+ /* move the pages across to the second bio
+ * and submit the write request
+ */
+ bio = r10_bio->devs[0].bio;
+ wbio = r10_bio->devs[1].bio;
+ for (i=0; i < wbio->bi_vcnt; i++) {
+ struct page *p = bio->bi_io_vec[i].bv_page;
+ bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page;
+ wbio->bi_io_vec[i].bv_page = p;
+ }
+ d = r10_bio->devs[1].devnum;
+
+ atomic_inc(&conf->mirrors[d].rdev->nr_pending);
+ md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
+ generic_make_request(wbio);
+}
+
+
+/*
+ * 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 syncronising.
+ */
+
+static void raid10d(mddev_t *mddev)
+{
+ r10bio_t *r10_bio;
+ struct bio *bio;
+ unsigned long flags;
+ conf_t *conf = mddev_to_conf(mddev);
+ struct list_head *head = &conf->retry_list;
+ int unplug=0;
+ mdk_rdev_t *rdev;
+
+ md_check_recovery(mddev);
+ md_handle_safemode(mddev);
+
+ for (;;) {
+ char b[BDEVNAME_SIZE];
+ spin_lock_irqsave(&conf->device_lock, flags);
+ if (list_empty(head))
+ break;
+ r10_bio = list_entry(head->prev, r10bio_t, retry_list);
+ list_del(head->prev);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+
+ mddev = r10_bio->mddev;
+ conf = mddev_to_conf(mddev);
+ if (test_bit(R10BIO_IsSync, &r10_bio->state)) {
+ sync_request_write(mddev, r10_bio);
+ unplug = 1;
+ } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) {
+ recovery_request_write(mddev, r10_bio);
+ unplug = 1;
+ } else {
+ int mirror;
+ bio = r10_bio->devs[r10_bio->read_slot].bio;
+ r10_bio->devs[r10_bio->read_slot].bio = NULL;
+ mirror = read_balance(conf, r10_bio);
+ r10_bio->devs[r10_bio->read_slot].bio = bio;
+ if (mirror == -1) {
+ printk(KERN_ALERT "raid10: %s: unrecoverable I/O"
+ " read error for block %llu\n",
+ bdevname(bio->bi_bdev,b),
+ (unsigned long long)r10_bio->sector);
+ raid_end_bio_io(r10_bio);
+ } else {
+ rdev = conf->mirrors[mirror].rdev;
+ if (printk_ratelimit())
+ printk(KERN_ERR "raid10: %s: redirecting sector %llu to"
+ " another mirror\n",
+ bdevname(rdev->bdev,b),
+ (unsigned long long)r10_bio->sector);
+ bio->bi_bdev = rdev->bdev;
+ bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr
+ + rdev->data_offset;
+ bio->bi_next = NULL;
+ bio->bi_flags &= (1<<BIO_CLONED);
+ bio->bi_flags |= 1 << BIO_UPTODATE;
+ bio->bi_idx = 0;
+ bio->bi_size = r10_bio->sectors << 9;
+ bio->bi_rw = READ;
+ unplug = 1;
+ generic_make_request(bio);
+ }
+ }
+ }
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ if (unplug)
+ unplug_slaves(mddev);
+}
+
+
+static int init_resync(conf_t *conf)
+{
+ int buffs;
+
+ buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
+ if (conf->r10buf_pool)
+ BUG();
+ 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 int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
+{
+ conf_t *conf = mddev_to_conf(mddev);
+ r10bio_t *r10_bio;
+ struct bio *biolist = NULL, *bio;
+ sector_t max_sector, nr_sectors;
+ int disk;
+ int i;
+
+ sector_t sectors_skipped = 0;
+ int chunks_skipped = 0;
+
+ if (!conf->r10buf_pool)
+ if (init_resync(conf))
+ return -ENOMEM;
+
+ skipped:
+ max_sector = mddev->size << 1;
+ if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
+ max_sector = mddev->resync_max_sectors;
+ if (sector_nr >= max_sector) {
+ close_sync(conf);
+ return sectors_skipped;
+ }
+ if (chunks_skipped >= conf->raid_disks) {
+ /* if there has been nothing to do on any drive,
+ * then there is nothing to do at all..
+ */
+ sector_t sec = max_sector - sector_nr;
+ md_done_sync(mddev, sec, 1);
+ return sec + sectors_skipped;
+ }
+
+ /* make sure whole request will fit in a chunk - if chunks
+ * are meaningful
+ */
+ if (conf->near_copies < conf->raid_disks &&
+ max_sector > (sector_nr | conf->chunk_mask))
+ max_sector = (sector_nr | conf->chunk_mask) + 1;
+ /*
+ * If there is non-resync activity waiting for us then
+ * put in a delay to throttle resync.
+ */
+ if (!go_faster && waitqueue_active(&conf->wait_resume))
+ schedule_timeout(HZ);
+ device_barrier(conf, sector_nr + RESYNC_SECTORS);
+
+ /* 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.
+ */
+
+ if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+ /* recovery... the complicated one */
+ int i, j, k;
+ r10_bio = NULL;
+
+ for (i=0 ; i<conf->raid_disks; i++)
+ if (conf->mirrors[i].rdev &&
+ !conf->mirrors[i].rdev->in_sync) {
+ /* want to reconstruct this device */
+ r10bio_t *rb2 = r10_bio;
+
+ r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
+ spin_lock_irq(&conf->resync_lock);
+ conf->nr_pending++;
+ if (rb2) conf->barrier++;
+ spin_unlock_irq(&conf->resync_lock);
+ 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 = raid10_find_virt(conf, sector_nr, i);
+ raid10_find_phys(conf, r10_bio);
+ for (j=0; j<conf->copies;j++) {
+ int d = r10_bio->devs[j].devnum;
+ if (conf->mirrors[d].rdev &&
+ conf->mirrors[d].rdev->in_sync) {
+ /* This is where we read from */
+ bio = r10_bio->devs[0].bio;
+ bio->bi_next = biolist;
+ biolist = bio;
+ bio->bi_private = r10_bio;
+ bio->bi_end_io = end_sync_read;
+ bio->bi_rw = 0;
+ bio->bi_sector = r10_bio->devs[j].addr +
+ conf->mirrors[d].rdev->data_offset;
+ bio->bi_bdev = conf->mirrors[d].rdev->bdev;
+ atomic_inc(&conf->mirrors[d].rdev->nr_pending);
+ atomic_inc(&r10_bio->remaining);
+ /* and we write to 'i' */
+
+ for (k=0; k<conf->copies; k++)
+ if (r10_bio->devs[k].devnum == i)
+ break;
+ bio = r10_bio->devs[1].bio;
+ bio->bi_next = biolist;
+ biolist = bio;
+ bio->bi_private = r10_bio;
+ bio->bi_end_io = end_sync_write;
+ bio->bi_rw = 1;
+ bio->bi_sector = r10_bio->devs[k].addr +
+ conf->mirrors[i].rdev->data_offset;
+ bio->bi_bdev = conf->mirrors[i].rdev->bdev;
+
+ r10_bio->devs[0].devnum = d;
+ r10_bio->devs[1].devnum = i;
+
+ break;
+ }
+ }
+ if (j == conf->copies) {
+ BUG();
+ }
+ }
+ if (biolist == NULL) {
+ while (r10_bio) {
+ r10bio_t *rb2 = r10_bio;
+ r10_bio = (r10bio_t*) 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;
+ r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
+
+ spin_lock_irq(&conf->resync_lock);
+ conf->nr_pending++;
+ spin_unlock_irq(&conf->resync_lock);
+
+ r10_bio->mddev = mddev;
+ atomic_set(&r10_bio->remaining, 0);
+
+ 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 | conf->chunk_mask) - sector_nr +1;
+ spin_lock_irq(&conf->device_lock);
+ for (i=0; i<conf->copies; i++) {
+ int d = r10_bio->devs[i].devnum;
+ bio = r10_bio->devs[i].bio;
+ bio->bi_end_io = NULL;
+ if (conf->mirrors[d].rdev == NULL ||
+ conf->mirrors[d].rdev->faulty)
+ continue;
+ atomic_inc(&conf->mirrors[d].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->bi_rw = 0;
+ bio->bi_sector = r10_bio->devs[i].addr +
+ conf->mirrors[d].rdev->data_offset;
+ bio->bi_bdev = conf->mirrors[d].rdev->bdev;
+ count++;
+ }
+ spin_unlock_irq(&conf->device_lock);
+ 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)
+ atomic_dec(&conf->mirrors[d].rdev->nr_pending);
+ }
+ put_buf(r10_bio);
+ goto giveup;
+ }
+ }
+
+ for (bio = biolist; bio ; bio=bio->bi_next) {
+
+ bio->bi_flags &= ~(BIO_POOL_MASK - 1);
+ if (bio->bi_end_io)
+ bio->bi_flags |= 1 << BIO_UPTODATE;
+ bio->bi_vcnt = 0;
+ bio->bi_idx = 0;
+ bio->bi_phys_segments = 0;
+ bio->bi_hw_segments = 0;
+ bio->bi_size = 0;
+ }
+
+ nr_sectors = 0;
+ do {
+ struct page *page;
+ int len = PAGE_SIZE;
+ disk = 0;
+ 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) {
+ page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
+ if (bio_add_page(bio, page, len, 0) == 0) {
+ /* stop here */
+ struct bio *bio2;
+ 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_size -= len;
+ bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
+ }
+ goto bio_full;
+ }
+ disk = i;
+ }
+ 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);
+ generic_make_request(bio);
+ }
+ }
+
+ return nr_sectors;
+ giveup:
+ /* There is nowhere to write, so all non-sync
+ * drives must be failed, so try the next chunk...
+ */
+ {
+ int sec = max_sector - sector_nr;
+ sectors_skipped += sec;
+ chunks_skipped ++;
+ sector_nr = max_sector;
+ md_done_sync(mddev, sec, 1);
+ goto skipped;
+ }
+}
+
+static int run(mddev_t *mddev)
+{
+ conf_t *conf;
+ int i, disk_idx;
+ mirror_info_t *disk;
+ mdk_rdev_t *rdev;
+ struct list_head *tmp;
+ int nc, fc;
+ sector_t stride, size;
+
+ if (mddev->level != 10) {
+ printk(KERN_ERR "raid10: %s: raid level not set correctly... (%d)\n",
+ mdname(mddev), mddev->level);
+ goto out;
+ }
+ nc = mddev->layout & 255;
+ fc = (mddev->layout >> 8) & 255;
+ if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
+ (mddev->layout >> 16)) {
+ printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n",
+ mdname(mddev), mddev->layout);
+ goto out;
+ }
+ /*
+ * copy the already verified devices into our private RAID10
+ * bookkeeping area. [whatever we allocate in run(),
+ * should be freed in stop()]
+ */
+ conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
+ mddev->private = conf;
+ if (!conf) {
+ printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
+ mdname(mddev));
+ goto out;
+ }
+ memset(conf, 0, sizeof(*conf));
+ conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks,
+ GFP_KERNEL);
+ if (!conf->mirrors) {
+ printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
+ mdname(mddev));
+ goto out_free_conf;
+ }
+ memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
+
+ conf->near_copies = nc;
+ conf->far_copies = fc;
+ conf->copies = nc*fc;
+ conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1;
+ conf->chunk_shift = ffz(~mddev->chunk_size) - 9;
+ stride = mddev->size >> (conf->chunk_shift-1);
+ sector_div(stride, fc);
+ conf->stride = stride << conf->chunk_shift;
+
+ conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
+ r10bio_pool_free, conf);
+ if (!conf->r10bio_pool) {
+ printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
+ mdname(mddev));
+ goto out_free_conf;
+ }
+ mddev->queue->unplug_fn = raid10_unplug;
+
+ mddev->queue->issue_flush_fn = raid10_issue_flush;
+
+ ITERATE_RDEV(mddev, rdev, tmp) {
+ disk_idx = rdev->raid_disk;
+ if (disk_idx >= mddev->raid_disks
+ || disk_idx < 0)
+ continue;
+ disk = conf->mirrors + disk_idx;
+
+ disk->rdev = rdev;
+
+ blk_queue_stack_limits(mddev->queue,
+ rdev->bdev->bd_disk->queue);
+ /* as we don't honour merge_bvec_fn, we must never risk
+ * violating it, so limit ->max_sector to one PAGE, as
+ * a one page request is never in violation.
+ */
+ if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
+ mddev->queue->max_sectors > (PAGE_SIZE>>9))
+ mddev->queue->max_sectors = (PAGE_SIZE>>9);
+
+ disk->head_position = 0;
+ if (!rdev->faulty && rdev->in_sync)
+ conf->working_disks++;
+ }
+ conf->raid_disks = mddev->raid_disks;
+ conf->mddev = mddev;
+ conf->device_lock = SPIN_LOCK_UNLOCKED;
+ INIT_LIST_HEAD(&conf->retry_list);
+
+ conf->resync_lock = SPIN_LOCK_UNLOCKED;
+ init_waitqueue_head(&conf->wait_idle);
+ init_waitqueue_head(&conf->wait_resume);
+
+ if (!conf->working_disks) {
+ printk(KERN_ERR "raid10: no operational mirrors for %s\n",
+ mdname(mddev));
+ goto out_free_conf;
+ }
+
+ mddev->degraded = 0;
+ for (i = 0; i < conf->raid_disks; i++) {
+
+ disk = conf->mirrors + i;
+
+ if (!disk->rdev) {
+ disk->head_position = 0;
+ mddev->degraded++;
+ }
+ }
+
+
+ mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10");
+ if (!mddev->thread) {
+ printk(KERN_ERR
+ "raid10: couldn't allocate thread for %s\n",
+ mdname(mddev));
+ goto out_free_conf;
+ }
+
+ printk(KERN_INFO
+ "raid10: raid set %s active with %d out of %d devices\n",
+ mdname(mddev), mddev->raid_disks - mddev->degraded,
+ mddev->raid_disks);
+ /*
+ * Ok, everything is just fine now
+ */
+ size = conf->stride * conf->raid_disks;
+ sector_div(size, conf->near_copies);
+ mddev->array_size = size/2;
+ mddev->resync_max_sectors = size;
+
+ /* Calculate max read-ahead size.
+ * We need to readahead at least twice a whole stripe....
+ * maybe...
+ */
+ {
+ int stripe = conf->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE;
+ stripe /= conf->near_copies;
+ if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
+ mddev->queue->backing_dev_info.ra_pages = 2* stripe;
+ }
+
+ if (conf->near_copies < mddev->raid_disks)
+ blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
+ return 0;
+
+out_free_conf:
+ if (conf->r10bio_pool)
+ mempool_destroy(conf->r10bio_pool);
+ if (conf->mirrors)
+ kfree(conf->mirrors);
+ kfree(conf);
+ mddev->private = NULL;
+out:
+ return -EIO;
+}
+
+static int stop(mddev_t *mddev)
+{
+ conf_t *conf = mddev_to_conf(mddev);
+
+ md_unregister_thread(mddev->thread);
+ mddev->thread = NULL;
+ if (conf->r10bio_pool)
+ mempool_destroy(conf->r10bio_pool);
+ if (conf->mirrors)
+ kfree(conf->mirrors);
+ kfree(conf);
+ mddev->private = NULL;
+ return 0;
+}
+
+
+static mdk_personality_t raid10_personality =
+{
+ .name = "raid10",
+ .owner = THIS_MODULE,
+ .make_request = make_request,
+ .run = run,
+ .stop = stop,
+ .status = status,
+ .error_handler = error,
+ .hot_add_disk = raid10_add_disk,
+ .hot_remove_disk= raid10_remove_disk,
+ .spare_active = raid10_spare_active,
+ .sync_request = sync_request,
+};
+
+static int __init raid_init(void)
+{
+ return register_md_personality(RAID10, &raid10_personality);
+}
+
+static void raid_exit(void)
+{
+ unregister_md_personality(RAID10);
+}
+
+module_init(raid_init);
+module_exit(raid_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("md-personality-9"); /* RAID10 */
git://git.onelab.eu / linux-2.6.git / blobdiff