Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
[safe/jmp/linux-2.6] / drivers / md / multipath.c
index 2ae2d70..41ced0c 100644 (file)
  * 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
+#include <linux/blkdev.h>
+#include <linux/raid/md_u.h>
+#include <linux/seq_file.h>
+#include "md.h"
+#include "multipath.h"
 
 #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;
@@ -63,8 +41,8 @@ static int multipath_map (multipath_conf_t *conf)
 
        rcu_read_lock();
        for (i = 0; i < disks; i++) {
-               mdk_rdev_t *rdev = conf->multipaths[i].rdev;
-               if (rdev && rdev->in_sync) {
+               mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
+               if (rdev && test_bit(In_sync, &rdev->flags)) {
                        atomic_inc(&rdev->nr_pending);
                        rcu_read_unlock();
                        return i;
@@ -99,21 +77,17 @@ 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);
+       bio_endio(bio, err);
        mempool_free(mp_bh, conf->pool);
 }
 
-static int multipath_end_request(struct bio *bio, unsigned int bytes_done,
-                                int error)
+static void multipath_end_request(struct bio *bio, 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)) {
@@ -129,7 +103,6 @@ static int multipath_end_request(struct bio *bio, unsigned int bytes_done,
        } else
                multipath_end_bh_io(mp_bh, error);
        rdev_dec_pending(rdev, conf->mddev);
-       return 0;
 }
 
 static void unplug_slaves(mddev_t *mddev)
@@ -139,15 +112,15 @@ static void unplug_slaves(mddev_t *mddev)
 
        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);
+               mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
+               if (rdev && !test_bit(Faulty, &rdev->flags)
+                   && atomic_read(&rdev->nr_pending)) {
+                       struct request_queue *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);
+                       blk_unplug(r_queue);
 
                        rdev_dec_pending(rdev, mddev);
                        rcu_read_lock();
@@ -156,35 +129,40 @@ static void unplug_slaves(mddev_t *mddev)
        rcu_read_unlock();
 }
 
-static void multipath_unplug(request_queue_t *q)
+static void multipath_unplug(struct request_queue *q)
 {
        unplug_slaves(q->queuedata);
 }
 
 
-static int multipath_make_request (request_queue_t *q, struct bio * bio)
+static int multipath_make_request (struct request_queue *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;
+       const int rw = bio_data_dir(bio);
+       int cpu;
+
+       if (unlikely(bio_barrier(bio))) {
+               bio_endio(bio, -EOPNOTSUPP);
+               return 0;
+       }
 
        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));
-       }
+       cpu = part_stat_lock();
+       part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
+       part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
+                     bio_sectors(bio));
+       part_stat_unlock();
 
        mp_bh->path = multipath_map(conf);
        if (mp_bh->path < 0) {
-               bio_endio(bio, bio->bi_size, -EIO);
+               bio_endio(bio, -EIO);
                mempool_free(mp_bh, conf->pool);
                return 0;
        }
@@ -193,7 +171,7 @@ static int multipath_make_request (request_queue_t *q, struct bio * bio)
        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_rw |= (1 << BIO_RW_FAILFAST_TRANSPORT);
        mp_bh->bio.bi_end_io = multipath_end_request;
        mp_bh->bio.bi_private = mp_bh;
        generic_make_request(&mp_bh->bio);
@@ -210,34 +188,27 @@ static void multipath_status (struct seq_file *seq, mddev_t *mddev)
        for (i = 0; i < conf->raid_disks; i++)
                seq_printf (seq, "%s",
                               conf->multipaths[i].rdev && 
-                              conf->multipaths[i].rdev->in_sync ? "U" : "_");
+                              test_bit(In_sync, &conf->multipaths[i].rdev->flags) ? "U" : "_");
        seq_printf (seq, "]");
 }
 
-static int multipath_issue_flush(request_queue_t *q, struct gendisk *disk,
-                                sector_t *error_sector)
+static int multipath_congested(void *data, int bits)
 {
-       mddev_t *mddev = q->queuedata;
+       mddev_t *mddev = data;
        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();
-                       }
+       for (i = 0; i < mddev->raid_disks ; i++) {
+               mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[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);
+                       /* Just like multipath_map, we just check the
+                        * first available device
+                        */
+                       break;
                }
        }
        rcu_read_unlock();
@@ -264,14 +235,16 @@ static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
                /*
                 * Mark disk as unusable
                 */
-               if (!rdev->faulty) {
+               if (!test_bit(Faulty, &rdev->flags)) {
                        char b[BDEVNAME_SIZE];
-                       rdev->in_sync = 0;
-                       rdev->faulty = 1;
-                       mddev->sb_dirty = 1;
+                       clear_bit(In_sync, &rdev->flags);
+                       set_bit(Faulty, &rdev->flags);
+                       set_bit(MD_CHANGE_DEVS, &mddev->flags);
                        conf->working_disks--;
+                       mddev->degraded++;
                        printk(KERN_ALERT "multipath: IO failure on %s,"
-                               " disabling IO path. \n Operation continuing"
+                               " disabling IO path.\n"
+                               "multipath: Operation continuing"
                                " on %d IO paths.\n",
                                bdevname (rdev->bdev,b),
                                conf->working_disks);
@@ -297,7 +270,7 @@ static void print_multipath_conf (multipath_conf_t *conf)
                tmp = conf->multipaths + i;
                if (tmp->rdev)
                        printk(" disk%d, o:%d, dev:%s\n",
-                               i,!tmp->rdev->faulty,
+                               i,!test_bit(Faulty, &tmp->rdev->flags),
                               bdevname(tmp->rdev->bdev,b));
        }
 }
@@ -306,16 +279,22 @@ static void print_multipath_conf (multipath_conf_t *conf)
 static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
        multipath_conf_t *conf = mddev->private;
-       int found = 0;
+       struct request_queue *q;
+       int err = -EEXIST;
        int path;
        struct multipath_info *p;
+       int first = 0;
+       int last = mddev->raid_disks - 1;
+
+       if (rdev->raid_disk >= 0)
+               first = last = rdev->raid_disk;
 
        print_multipath_conf(conf);
 
-       for (path=0; path<mddev->raid_disks; path++) 
+       for (path = first; path <= last; path++)
                if ((p=conf->multipaths+path)->rdev == NULL) {
-                       blk_queue_stack_limits(mddev->queue,
-                                              rdev->bdev->bd_disk->queue);
+                       q = rdev->bdev->bd_disk->queue;
+                       blk_queue_stack_limits(mddev->queue, q);
 
                /* as we don't honour merge_bvec_fn, we must never risk
                 * violating it, so limit ->max_sector to one PAGE, as
@@ -323,19 +302,22 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                 * (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 &&
+                       if (q->merge_bvec_fn &&
                            mddev->queue->max_sectors > (PAGE_SIZE>>9))
                                blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 
                        conf->working_disks++;
+                       mddev->degraded--;
                        rdev->raid_disk = path;
-                       rdev->in_sync = 1;
-                       p->rdev = rdev;
-                       found = 1;
+                       set_bit(In_sync, &rdev->flags);
+                       rcu_assign_pointer(p->rdev, rdev);
+                       err = 0;
+                       break;
                }
 
        print_multipath_conf(conf);
-       return found;
+
+       return err;
 }
 
 static int multipath_remove_disk(mddev_t *mddev, int number)
@@ -349,9 +331,10 @@ static int multipath_remove_disk(mddev_t *mddev, int number)
 
        rdev = p->rdev;
        if (rdev) {
-               if (rdev->in_sync ||
+               if (test_bit(In_sync, &rdev->flags) ||
                    atomic_read(&rdev->nr_pending)) {
-                       printk(KERN_ERR "hot-remove-disk, slot %d is identified"                                " but is still operational!\n", number);
+                       printk(KERN_ERR "hot-remove-disk, slot %d is identified"
+                              " but is still operational!\n", number);
                        err = -EBUSY;
                        goto abort;
                }
@@ -414,7 +397,7 @@ static void multipathd (mddev_t *mddev)
                        *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_rw |= (1 << BIO_RW_FAILFAST_TRANSPORT);
                        bio->bi_end_io = multipath_end_request;
                        bio->bi_private = mp_bh;
                        generic_make_request(bio);
@@ -423,13 +406,20 @@ static void multipathd (mddev_t *mddev)
        spin_unlock_irqrestore(&conf->device_lock, flags);
 }
 
+static sector_t multipath_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+       WARN_ONCE(sectors || raid_disks,
+                 "%s does not support generic reshape\n", __func__);
+
+       return mddev->dev_sectors;
+}
+
 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",
@@ -441,8 +431,9 @@ static int multipath_run (mddev_t *mddev)
         * bookkeeping area. [whatever we allocate in multipath_run(),
         * should be freed in multipath_stop()]
         */
+       mddev->queue->queue_lock = &mddev->queue->__queue_lock;
 
-       conf = kmalloc(sizeof(multipath_conf_t), GFP_KERNEL);
+       conf = kzalloc(sizeof(multipath_conf_t), GFP_KERNEL);
        mddev->private = conf;
        if (!conf) {
                printk(KERN_ERR 
@@ -450,9 +441,8 @@ static int multipath_run (mddev_t *mddev)
                        mdname(mddev));
                goto out;
        }
-       memset(conf, 0, sizeof(*conf));
 
-       conf->multipaths = kmalloc(sizeof(struct multipath_info)*mddev->raid_disks,
+       conf->multipaths = kzalloc(sizeof(struct multipath_info)*mddev->raid_disks,
                                   GFP_KERNEL);
        if (!conf->multipaths) {
                printk(KERN_ERR 
@@ -460,10 +450,9 @@ static int multipath_run (mddev_t *mddev)
                        mdname(mddev));
                goto out_free_conf;
        }
-       memset(conf->multipaths, 0, sizeof(struct multipath_info)*mddev->raid_disks);
 
        conf->working_disks = 0;
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       list_for_each_entry(rdev, &mddev->disks, same_set) {
                disk_idx = rdev->raid_disk;
                if (disk_idx < 0 ||
                    disk_idx >= mddev->raid_disks)
@@ -481,12 +470,11 @@ static int multipath_run (mddev_t *mddev)
                    mddev->queue->max_sectors > (PAGE_SIZE>>9))
                        blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 
-               if (!rdev->faulty) 
+               if (!test_bit(Faulty, &rdev->flags))
                        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);
@@ -496,11 +484,10 @@ static int multipath_run (mddev_t *mddev)
                        mdname(mddev));
                goto out_free_conf;
        }
-       mddev->degraded = conf->raid_disks = conf->working_disks;
+       mddev->degraded = conf->raid_disks - conf->working_disks;
 
-       conf->pool = mempool_create(NR_RESERVED_BUFS,
-                                   mp_pool_alloc, mp_pool_free,
-                                   NULL);
+       conf->pool = mempool_create_kzalloc_pool(NR_RESERVED_BUFS,
+                                                sizeof(struct multipath_bh));
        if (conf->pool == NULL) {
                printk(KERN_ERR 
                        "multipath: couldn't allocate memory for %s\n",
@@ -523,18 +510,18 @@ static int multipath_run (mddev_t *mddev)
        /*
         * Ok, everything is just fine now
         */
-       mddev->array_size = mddev->size;
+       md_set_array_sectors(mddev, multipath_size(mddev, 0, 0));
 
        mddev->queue->unplug_fn = multipath_unplug;
-       mddev->queue->issue_flush_fn = multipath_issue_flush;
+       mddev->queue->backing_dev_info.congested_fn = multipath_congested;
+       mddev->queue->backing_dev_info.congested_data = mddev;
 
        return 0;
 
 out_free_conf:
        if (conf->pool)
                mempool_destroy(conf->pool);
-       if (conf->multipaths)
-               kfree(conf->multipaths);
+       kfree(conf->multipaths);
        kfree(conf);
        mddev->private = NULL;
 out:
@@ -556,9 +543,10 @@ static int multipath_stop (mddev_t *mddev)
        return 0;
 }
 
-static mdk_personality_t multipath_personality=
+static struct mdk_personality multipath_personality =
 {
        .name           = "multipath",
+       .level          = LEVEL_MULTIPATH,
        .owner          = THIS_MODULE,
        .make_request   = multipath_make_request,
        .run            = multipath_run,
@@ -567,19 +555,22 @@ static mdk_personality_t multipath_personality=
        .error_handler  = multipath_error,
        .hot_add_disk   = multipath_add_disk,
        .hot_remove_disk= multipath_remove_disk,
+       .size           = multipath_size,
 };
 
 static int __init multipath_init (void)
 {
-       return register_md_personality (MULTIPATH, &multipath_personality);
+       return register_md_personality (&multipath_personality);
 }
 
 static void __exit multipath_exit (void)
 {
-       unregister_md_personality (MULTIPATH);
+       unregister_md_personality (&multipath_personality);
 }
 
 module_init(multipath_init);
 module_exit(multipath_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-7"); /* MULTIPATH */
+MODULE_ALIAS("md-multipath");
+MODULE_ALIAS("md-level--4");