Linux kernel MD Source code interpretation of the process of four command character Run_array

Running the array means that the array goes from scratch, establishes the attributes (such as synchronous reconstruction) that should be used as a raid, and paves the ground for subsequent reads and writes. So what did you do when you ran the array, making the original disk a new Big Mac like a transformer? Now let's look at the array run process:

5158 static int Do_md_run (struct Mddev *mddev)  
5159 {  
5160         int err;  
5161   
5162         err = Md_run (Mddev);  
5163         if (err)  
5164                 goto out;  
5165         err = bitmap_load (Mddev);  
5166         if (err) {  
5167                 Bitmap_destroy (mddev);  
5168                 goto out;  
5169         }  
5170   
5171         md_wakeup_thread (mddev->thread);  
5172         Md_wakeup_thread (mddev->sync_thread);/* Possibly kick off a reshape */5173 5174 set_capacity         ( Mddev->gendisk, mddev->array_sectors);  
5175         Revalidate_disk (mddev->gendisk);  
5176         mddev->changed = 1;  
5177         kobject_uevent (&disk_to_dev (Mddev->gendisk)->kobj, kobj_change);  
5178 out:  
5179 return         err;  
5180}

If the process of running an array is a book, then this function is the directory of the book, each containing a profound story.

5162 lines, Md_run run the array, this function is relatively long, we follow a paragraph to analyze:

4956 int Md_run (struct Mddev *mddev)  
4957 {  
4958         int err;  
4959         struct Md_rdev *rdev;  
4960         struct md_personality *pers;  
4961   
4962         if (List_empty (&mddev->disks))  
4963/                 * cannot run an array with no devices. * *
4964                 return-einval;  
4965   
4966         if (mddev->pers)  
4967                 return-ebusy;  
4968         /* cannot run until previous stop completes properly         /4969 if (mddev->sysfs_active)  
4970< C25/>return-ebusy;  
4971   
4972         /          * 4973 * Analyze all RAID superblock (s) 
4974/
4975         if (!mddev- >raid_disks) {  
4976                 if (!mddev->persistent)  
4977                         return-einval;  
4978                 Analyze_sbs (mddev);  
4979         }