diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c index aba3c4ab5..69bc53b4b 100644 --- a/module/zfs/vdev_disk.c +++ b/module/zfs/vdev_disk.c @@ -119,24 +119,42 @@ vdev_disk_error(zio_t *zio) * open time from the kernel. */ static int -vdev_elevator_switch(vdev_t *v, char *elevator, char *device) +vdev_elevator_switch(vdev_t *v, char *elevator) { + vdev_disk_t *vd = v->vdev_tsd; + struct block_device *bdev = vd->vd_bdev; + struct request_queue *q = bdev_get_queue(bdev); + char *device = bdev->bd_disk->disk_name; char sh_path[] = "/bin/sh"; char sh_cmd[128]; char *argv[] = { sh_path, "-c", sh_cmd }; char *envp[] = { NULL }; - int error; + int count = 0, error; + /* Skip devices without schedulers (loop, ram, dm, etc) */ + if (!q->elevator || !blk_queue_stackable(q)) + return (0); + + /* Leave existing scheduler when set to "none" */ if (!strncmp(elevator, "none", 4) && (strlen(elevator) == 4)) return (0); + /* + * Set the desired scheduler with a three attempt retry for + * -EFAULT which has been observed to occur spuriously. + */ sprintf(sh_cmd, "%s \"%s\" >/sys/block/%s/queue/scheduler", "/bin/echo", elevator, device); - error = call_usermodehelper(sh_path, argv, envp, 1); + while (++count <= 3) { + error = call_usermodehelper(sh_path, argv, envp, 1); + if ((error == 0) || (error != -EFAULT)) + break; + } + if (error) printk("ZFS: Unable to set \"%s\" scheduler for %s (%s): %d\n", - elevator, v->vdev_path, device, error); + elevator, v->vdev_path, device, error); return (error); } @@ -207,8 +225,7 @@ vdev_disk_open(vdev_t *v, uint64_t *psize, uint64_t *ashift) *ashift = highbit(MAX(block_size, SPA_MINBLOCKSIZE)) - 1; /* Try to set the io scheduler elevator algorithm */ - (void) vdev_elevator_switch(v, zfs_vdev_scheduler, - bdev->bd_disk->disk_name); + (void) vdev_elevator_switch(v, zfs_vdev_scheduler); return 0; }