Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
new file mode 100644
index 0000000..c9b134c
--- /dev/null
+++ b/drivers/md/multipath.c
@@ -0,0 +1,584 @@
+/*
+ * multipath.c : Multiple Devices driver for Linux
+ *
+ * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
+ *
+ * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
+ *
+ * MULTIPATH management functions.
+ *
+ * derived from raid1.c.
+ *
+ * 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/module.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/raid/multipath.h>
+#include <linux/buffer_head.h>
+#include <asm/atomic.h>
+
+#define MAJOR_NR MD_MAJOR
+#define MD_DRIVER
+#define MD_PERSONALITY
+
+#define MAX_WORK_PER_DISK 128
+
+#define NR_RESERVED_BUFS 32
+
+
+static mdk_personality_t multipath_personality;
+
+
+static void *mp_pool_alloc(unsigned int __nocast gfp_flags, void *data)
+{
+ struct multipath_bh *mpb;
+ mpb = kmalloc(sizeof(*mpb), gfp_flags);
+ if (mpb)
+ memset(mpb, 0, sizeof(*mpb));
+ return mpb;
+}
+
+static void mp_pool_free(void *mpb, void *data)
+{
+ kfree(mpb);
+}
+
+static int multipath_map (multipath_conf_t *conf)
+{
+ int i, disks = conf->raid_disks;
+
+ /*
+ * Later we do read balancing on the read side
+ * now we use the first available disk.
+ */
+
+ rcu_read_lock();
+ for (i = 0; i < disks; i++) {
+ mdk_rdev_t *rdev = conf->multipaths[i].rdev;
+ if (rdev && rdev->in_sync) {
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+ return i;
+ }
+ }
+ rcu_read_unlock();
+
+ printk(KERN_ERR "multipath_map(): no more operational IO paths?\n");
+ return (-1);
+}
+
+static void multipath_reschedule_retry (struct multipath_bh *mp_bh)
+{
+ unsigned long flags;
+ mddev_t *mddev = mp_bh->mddev;
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+ list_add(&mp_bh->retry_list, &conf->retry_list);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ md_wakeup_thread(mddev->thread);
+}
+
+
+/*
+ * multipath_end_bh_io() is called when we have finished servicing a multipathed
+ * operation and are ready to return a success/failure code to the buffer
+ * cache layer.
+ */
+static void multipath_end_bh_io (struct multipath_bh *mp_bh, int err)
+{
+ struct bio *bio = mp_bh->master_bio;
+ multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev);
+
+ bio_endio(bio, bio->bi_size, err);
+ mempool_free(mp_bh, conf->pool);
+}
+
+int multipath_end_request(struct bio *bio, unsigned int bytes_done, int error)
+{
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ struct multipath_bh * mp_bh = (struct multipath_bh *)(bio->bi_private);
+ multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev);
+ mdk_rdev_t *rdev = conf->multipaths[mp_bh->path].rdev;
+
+ if (bio->bi_size)
+ return 1;
+
+ if (uptodate)
+ multipath_end_bh_io(mp_bh, 0);
+ else if (!bio_rw_ahead(bio)) {
+ /*
+ * oops, IO error:
+ */
+ char b[BDEVNAME_SIZE];
+ md_error (mp_bh->mddev, rdev);
+ printk(KERN_ERR "multipath: %s: rescheduling sector %llu\n",
+ bdevname(rdev->bdev,b),
+ (unsigned long long)bio->bi_sector);
+ multipath_reschedule_retry(mp_bh);
+ } else
+ multipath_end_bh_io(mp_bh, error);
+ rdev_dec_pending(rdev, conf->mddev);
+ return 0;
+}
+
+static void unplug_slaves(mddev_t *mddev)
+{
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+ int i;
+
+ rcu_read_lock();
+ for (i=0; i<mddev->raid_disks; i++) {
+ mdk_rdev_t *rdev = conf->multipaths[i].rdev;
+ if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
+ request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
+
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+
+ if (r_queue->unplug_fn)
+ r_queue->unplug_fn(r_queue);
+
+ rdev_dec_pending(rdev, mddev);
+ rcu_read_lock();
+ }
+ }
+ rcu_read_unlock();
+}
+
+static void multipath_unplug(request_queue_t *q)
+{
+ unplug_slaves(q->queuedata);
+}
+
+
+static int multipath_make_request (request_queue_t *q, struct bio * bio)
+{
+ mddev_t *mddev = q->queuedata;
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+ struct multipath_bh * mp_bh;
+ struct multipath_info *multipath;
+
+ mp_bh = mempool_alloc(conf->pool, GFP_NOIO);
+
+ mp_bh->master_bio = bio;
+ mp_bh->mddev = mddev;
+
+ 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));
+ }
+
+ mp_bh->path = multipath_map(conf);
+ if (mp_bh->path < 0) {
+ bio_endio(bio, bio->bi_size, -EIO);
+ mempool_free(mp_bh, conf->pool);
+ return 0;
+ }
+ multipath = conf->multipaths + mp_bh->path;
+
+ mp_bh->bio = *bio;
+ mp_bh->bio.bi_sector += multipath->rdev->data_offset;
+ mp_bh->bio.bi_bdev = multipath->rdev->bdev;
+ mp_bh->bio.bi_rw |= (1 << BIO_RW_FAILFAST);
+ mp_bh->bio.bi_end_io = multipath_end_request;
+ mp_bh->bio.bi_private = mp_bh;
+ generic_make_request(&mp_bh->bio);
+ return 0;
+}
+
+static void multipath_status (struct seq_file *seq, mddev_t *mddev)
+{
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+ int i;
+
+ seq_printf (seq, " [%d/%d] [", conf->raid_disks,
+ conf->working_disks);
+ for (i = 0; i < conf->raid_disks; i++)
+ seq_printf (seq, "%s",
+ conf->multipaths[i].rdev &&
+ conf->multipaths[i].rdev->in_sync ? "U" : "_");
+ seq_printf (seq, "]");
+}
+
+static int multipath_issue_flush(request_queue_t *q, struct gendisk *disk,
+ sector_t *error_sector)
+{
+ mddev_t *mddev = q->queuedata;
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+ int i, ret = 0;
+
+ rcu_read_lock();
+ for (i=0; i<mddev->raid_disks && ret == 0; i++) {
+ mdk_rdev_t *rdev = conf->multipaths[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 = -EOPNOTSUPP;
+ else {
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+ ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
+ error_sector);
+ rdev_dec_pending(rdev, mddev);
+ rcu_read_lock();
+ }
+ }
+ }
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Careful, this can execute in IRQ contexts as well!
+ */
+static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
+{
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+
+ if (conf->working_disks <= 1) {
+ /*
+ * Uh oh, we can do nothing if this is our last path, but
+ * first check if this is a queued request for a device
+ * which has just failed.
+ */
+ printk(KERN_ALERT
+ "multipath: only one IO path left and IO error.\n");
+ /* leave it active... it's all we have */
+ } else {
+ /*
+ * Mark disk as unusable
+ */
+ if (!rdev->faulty) {
+ char b[BDEVNAME_SIZE];
+ rdev->in_sync = 0;
+ rdev->faulty = 1;
+ mddev->sb_dirty = 1;
+ conf->working_disks--;
+ printk(KERN_ALERT "multipath: IO failure on %s,"
+ " disabling IO path. \n Operation continuing"
+ " on %d IO paths.\n",
+ bdevname (rdev->bdev,b),
+ conf->working_disks);
+ }
+ }
+}
+
+static void print_multipath_conf (multipath_conf_t *conf)
+{
+ int i;
+ struct multipath_info *tmp;
+
+ printk("MULTIPATH conf printout:\n");
+ if (!conf) {
+ printk("(conf==NULL)\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->multipaths + i;
+ if (tmp->rdev)
+ printk(" disk%d, o:%d, dev:%s\n",
+ i,!tmp->rdev->faulty,
+ bdevname(tmp->rdev->bdev,b));
+ }
+}
+
+
+static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+ multipath_conf_t *conf = mddev->private;
+ int found = 0;
+ int path;
+ struct multipath_info *p;
+
+ print_multipath_conf(conf);
+
+ for (path=0; path<mddev->raid_disks; path++)
+ if ((p=conf->multipaths+path)->rdev == NULL) {
+ 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.
+ * (Note: it is very unlikely that a device with
+ * merge_bvec_fn will be involved in multipath.)
+ */
+ if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
+ mddev->queue->max_sectors > (PAGE_SIZE>>9))
+ blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+
+ conf->working_disks++;
+ rdev->raid_disk = path;
+ rdev->in_sync = 1;
+ p->rdev = rdev;
+ found = 1;
+ }
+
+ print_multipath_conf(conf);
+ return found;
+}
+
+static int multipath_remove_disk(mddev_t *mddev, int number)
+{
+ multipath_conf_t *conf = mddev->private;
+ int err = 0;
+ mdk_rdev_t *rdev;
+ struct multipath_info *p = conf->multipaths + number;
+
+ print_multipath_conf(conf);
+
+ rdev = p->rdev;
+ if (rdev) {
+ if (rdev->in_sync ||
+ atomic_read(&rdev->nr_pending)) {
+ printk(KERN_ERR "hot-remove-disk, slot %d is identified" " but is still operational!\n", number);
+ err = -EBUSY;
+ goto abort;
+ }
+ p->rdev = NULL;
+ synchronize_kernel();
+ if (atomic_read(&rdev->nr_pending)) {
+ /* lost the race, try later */
+ err = -EBUSY;
+ p->rdev = rdev;
+ }
+ }
+abort:
+
+ print_multipath_conf(conf);
+ return err;
+}
+
+
+
+/*
+ * This is a kernel thread which:
+ *
+ * 1. Retries failed read operations on working multipaths.
+ * 2. Updates the raid superblock when problems encounter.
+ * 3. Performs writes following reads for array syncronising.
+ */
+
+static void multipathd (mddev_t *mddev)
+{
+ struct multipath_bh *mp_bh;
+ struct bio *bio;
+ unsigned long flags;
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+ struct list_head *head = &conf->retry_list;
+
+ md_check_recovery(mddev);
+ for (;;) {
+ char b[BDEVNAME_SIZE];
+ spin_lock_irqsave(&conf->device_lock, flags);
+ if (list_empty(head))
+ break;
+ mp_bh = list_entry(head->prev, struct multipath_bh, retry_list);
+ list_del(head->prev);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+
+ bio = &mp_bh->bio;
+ bio->bi_sector = mp_bh->master_bio->bi_sector;
+
+ if ((mp_bh->path = multipath_map (conf))<0) {
+ printk(KERN_ALERT "multipath: %s: unrecoverable IO read"
+ " error for block %llu\n",
+ bdevname(bio->bi_bdev,b),
+ (unsigned long long)bio->bi_sector);
+ multipath_end_bh_io(mp_bh, -EIO);
+ } else {
+ printk(KERN_ERR "multipath: %s: redirecting sector %llu"
+ " to another IO path\n",
+ bdevname(bio->bi_bdev,b),
+ (unsigned long long)bio->bi_sector);
+ *bio = *(mp_bh->master_bio);
+ bio->bi_sector += conf->multipaths[mp_bh->path].rdev->data_offset;
+ bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev;
+ bio->bi_rw |= (1 << BIO_RW_FAILFAST);
+ bio->bi_end_io = multipath_end_request;
+ bio->bi_private = mp_bh;
+ generic_make_request(bio);
+ }
+ }
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+}
+
+static int multipath_run (mddev_t *mddev)
+{
+ multipath_conf_t *conf;
+ int disk_idx;
+ struct multipath_info *disk;
+ mdk_rdev_t *rdev;
+ struct list_head *tmp;
+
+ if (mddev->level != LEVEL_MULTIPATH) {
+ printk("multipath: %s: raid level not set to multipath IO (%d)\n",
+ mdname(mddev), mddev->level);
+ goto out;
+ }
+ /*
+ * copy the already verified devices into our private MULTIPATH
+ * bookkeeping area. [whatever we allocate in multipath_run(),
+ * should be freed in multipath_stop()]
+ */
+
+ conf = kmalloc(sizeof(multipath_conf_t), GFP_KERNEL);
+ mddev->private = conf;
+ if (!conf) {
+ printk(KERN_ERR
+ "multipath: couldn't allocate memory for %s\n",
+ mdname(mddev));
+ goto out;
+ }
+ memset(conf, 0, sizeof(*conf));
+
+ conf->multipaths = kmalloc(sizeof(struct multipath_info)*mddev->raid_disks,
+ GFP_KERNEL);
+ if (!conf->multipaths) {
+ printk(KERN_ERR
+ "multipath: couldn't allocate memory for %s\n",
+ mdname(mddev));
+ goto out_free_conf;
+ }
+ memset(conf->multipaths, 0, sizeof(struct multipath_info)*mddev->raid_disks);
+
+ mddev->queue->unplug_fn = multipath_unplug;
+
+ mddev->queue->issue_flush_fn = multipath_issue_flush;
+
+ conf->working_disks = 0;
+ ITERATE_RDEV(mddev,rdev,tmp) {
+ disk_idx = rdev->raid_disk;
+ if (disk_idx < 0 ||
+ disk_idx >= mddev->raid_disks)
+ continue;
+
+ disk = conf->multipaths + 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, not that we ever expect a device with
+ * a merge_bvec_fn to be involved in multipath */
+ if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
+ mddev->queue->max_sectors > (PAGE_SIZE>>9))
+ blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+
+ if (!rdev->faulty)
+ conf->working_disks++;
+ }
+
+ conf->raid_disks = mddev->raid_disks;
+ mddev->sb_dirty = 1;
+ conf->mddev = mddev;
+ spin_lock_init(&conf->device_lock);
+ INIT_LIST_HEAD(&conf->retry_list);
+
+ if (!conf->working_disks) {
+ printk(KERN_ERR "multipath: no operational IO paths for %s\n",
+ mdname(mddev));
+ goto out_free_conf;
+ }
+ mddev->degraded = conf->raid_disks = conf->working_disks;
+
+ conf->pool = mempool_create(NR_RESERVED_BUFS,
+ mp_pool_alloc, mp_pool_free,
+ NULL);
+ if (conf->pool == NULL) {
+ printk(KERN_ERR
+ "multipath: couldn't allocate memory for %s\n",
+ mdname(mddev));
+ goto out_free_conf;
+ }
+
+ {
+ mddev->thread = md_register_thread(multipathd, mddev, "%s_multipath");
+ if (!mddev->thread) {
+ printk(KERN_ERR "multipath: couldn't allocate thread"
+ " for %s\n", mdname(mddev));
+ goto out_free_conf;
+ }
+ }
+
+ printk(KERN_INFO
+ "multipath: array %s active with %d out of %d IO paths\n",
+ mdname(mddev), conf->working_disks, mddev->raid_disks);
+ /*
+ * Ok, everything is just fine now
+ */
+ mddev->array_size = mddev->size;
+ return 0;
+
+out_free_conf:
+ if (conf->pool)
+ mempool_destroy(conf->pool);
+ if (conf->multipaths)
+ kfree(conf->multipaths);
+ kfree(conf);
+ mddev->private = NULL;
+out:
+ return -EIO;
+}
+
+
+static int multipath_stop (mddev_t *mddev)
+{
+ multipath_conf_t *conf = mddev_to_conf(mddev);
+
+ md_unregister_thread(mddev->thread);
+ mddev->thread = NULL;
+ blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
+ mempool_destroy(conf->pool);
+ kfree(conf->multipaths);
+ kfree(conf);
+ mddev->private = NULL;
+ return 0;
+}
+
+static mdk_personality_t multipath_personality=
+{
+ .name = "multipath",
+ .owner = THIS_MODULE,
+ .make_request = multipath_make_request,
+ .run = multipath_run,
+ .stop = multipath_stop,
+ .status = multipath_status,
+ .error_handler = multipath_error,
+ .hot_add_disk = multipath_add_disk,
+ .hot_remove_disk= multipath_remove_disk,
+};
+
+static int __init multipath_init (void)
+{
+ return register_md_personality (MULTIPATH, &multipath_personality);
+}
+
+static void __exit multipath_exit (void)
+{
+ unregister_md_personality (MULTIPATH);
+}
+
+module_init(multipath_init);
+module_exit(multipath_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("md-personality-7"); /* MULTIPATH */