md: avoid taking the mutex on some ioctls.
Some ioctls don't need to take the mutex and doing so can cause a delay as it is held during super-block update. So move those ioctls out of the mutex and rely on rcu locking to ensure we don't access stale data. Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
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4ed8731d8e
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1ca69c4bc4
1 changed files with 62 additions and 23 deletions
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@ -674,7 +674,18 @@ static struct md_rdev * find_rdev_nr(struct mddev *mddev, int nr)
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return NULL;
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return NULL;
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}
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}
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static struct md_rdev * find_rdev(struct mddev * mddev, dev_t dev)
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static struct md_rdev *find_rdev_nr_rcu(struct mddev *mddev, int nr)
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{
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struct md_rdev *rdev;
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rdev_for_each_rcu(rdev, mddev)
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if (rdev->desc_nr == nr)
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return rdev;
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return NULL;
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}
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static struct md_rdev *find_rdev(struct mddev *mddev, dev_t dev)
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{
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{
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struct md_rdev *rdev;
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struct md_rdev *rdev;
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@ -685,6 +696,17 @@ static struct md_rdev * find_rdev(struct mddev * mddev, dev_t dev)
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return NULL;
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return NULL;
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}
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}
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static struct md_rdev *find_rdev_rcu(struct mddev *mddev, dev_t dev)
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{
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struct md_rdev *rdev;
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rdev_for_each_rcu(rdev, mddev)
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if (rdev->bdev->bd_dev == dev)
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return rdev;
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return NULL;
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}
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static struct md_personality *find_pers(int level, char *clevel)
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static struct md_personality *find_pers(int level, char *clevel)
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{
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{
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struct md_personality *pers;
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struct md_personality *pers;
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@ -5509,8 +5531,9 @@ static int get_array_info(struct mddev * mddev, void __user * arg)
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int nr,working,insync,failed,spare;
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int nr,working,insync,failed,spare;
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struct md_rdev *rdev;
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struct md_rdev *rdev;
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nr=working=insync=failed=spare=0;
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nr = working = insync = failed = spare = 0;
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rdev_for_each(rdev, mddev) {
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rcu_read_lock();
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rdev_for_each_rcu(rdev, mddev) {
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nr++;
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nr++;
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if (test_bit(Faulty, &rdev->flags))
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if (test_bit(Faulty, &rdev->flags))
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failed++;
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failed++;
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@ -5522,6 +5545,7 @@ static int get_array_info(struct mddev * mddev, void __user * arg)
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spare++;
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spare++;
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}
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}
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}
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}
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rcu_read_unlock();
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info.major_version = mddev->major_version;
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info.major_version = mddev->major_version;
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info.minor_version = mddev->minor_version;
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info.minor_version = mddev->minor_version;
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@ -5605,7 +5629,8 @@ static int get_disk_info(struct mddev * mddev, void __user * arg)
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if (copy_from_user(&info, arg, sizeof(info)))
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if (copy_from_user(&info, arg, sizeof(info)))
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return -EFAULT;
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return -EFAULT;
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rdev = find_rdev_nr(mddev, info.number);
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rcu_read_lock();
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rdev = find_rdev_nr_rcu(mddev, info.number);
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if (rdev) {
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if (rdev) {
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info.major = MAJOR(rdev->bdev->bd_dev);
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info.major = MAJOR(rdev->bdev->bd_dev);
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info.minor = MINOR(rdev->bdev->bd_dev);
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info.minor = MINOR(rdev->bdev->bd_dev);
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@ -5624,6 +5649,7 @@ static int get_disk_info(struct mddev * mddev, void __user * arg)
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info.raid_disk = -1;
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info.raid_disk = -1;
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info.state = (1<<MD_DISK_REMOVED);
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info.state = (1<<MD_DISK_REMOVED);
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}
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}
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rcu_read_unlock();
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if (copy_to_user(arg, &info, sizeof(info)))
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if (copy_to_user(arg, &info, sizeof(info)))
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return -EFAULT;
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return -EFAULT;
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@ -6232,18 +6258,22 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
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static int set_disk_faulty(struct mddev *mddev, dev_t dev)
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static int set_disk_faulty(struct mddev *mddev, dev_t dev)
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{
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{
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struct md_rdev *rdev;
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struct md_rdev *rdev;
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int err = 0;
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if (mddev->pers == NULL)
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if (mddev->pers == NULL)
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return -ENODEV;
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return -ENODEV;
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rdev = find_rdev(mddev, dev);
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rcu_read_lock();
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rdev = find_rdev_rcu(mddev, dev);
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if (!rdev)
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if (!rdev)
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return -ENODEV;
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err = -ENODEV;
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else {
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md_error(mddev, rdev);
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md_error(mddev, rdev);
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if (!test_bit(Faulty, &rdev->flags))
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if (!test_bit(Faulty, &rdev->flags))
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return -EBUSY;
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err = -EBUSY;
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return 0;
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}
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rcu_read_unlock();
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return err;
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}
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}
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/*
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/*
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@ -6315,6 +6345,27 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
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goto abort;
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goto abort;
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}
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}
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/* Some actions do not requires the mutex */
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switch (cmd) {
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case GET_ARRAY_INFO:
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if (!mddev->raid_disks && !mddev->external)
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err = -ENODEV;
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else
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err = get_array_info(mddev, argp);
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goto abort;
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case GET_DISK_INFO:
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if (!mddev->raid_disks && !mddev->external)
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err = -ENODEV;
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else
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err = get_disk_info(mddev, argp);
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goto abort;
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case SET_DISK_FAULTY:
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err = set_disk_faulty(mddev, new_decode_dev(arg));
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goto abort;
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}
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err = mddev_lock(mddev);
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err = mddev_lock(mddev);
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if (err) {
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if (err) {
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printk(KERN_INFO
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printk(KERN_INFO
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@ -6387,18 +6438,10 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
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*/
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*/
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switch (cmd)
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switch (cmd)
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{
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{
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case GET_ARRAY_INFO:
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err = get_array_info(mddev, argp);
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goto done_unlock;
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case GET_BITMAP_FILE:
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case GET_BITMAP_FILE:
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err = get_bitmap_file(mddev, argp);
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err = get_bitmap_file(mddev, argp);
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goto done_unlock;
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goto done_unlock;
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case GET_DISK_INFO:
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err = get_disk_info(mddev, argp);
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goto done_unlock;
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case RESTART_ARRAY_RW:
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case RESTART_ARRAY_RW:
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err = restart_array(mddev);
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err = restart_array(mddev);
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goto done_unlock;
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goto done_unlock;
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@ -6480,10 +6523,6 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
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err = hot_add_disk(mddev, new_decode_dev(arg));
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err = hot_add_disk(mddev, new_decode_dev(arg));
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goto done_unlock;
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goto done_unlock;
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case SET_DISK_FAULTY:
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err = set_disk_faulty(mddev, new_decode_dev(arg));
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goto done_unlock;
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case RUN_ARRAY:
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case RUN_ARRAY:
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err = do_md_run(mddev);
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err = do_md_run(mddev);
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goto done_unlock;
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goto done_unlock;
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