Algorithm: 1. Node 1 issues mdadm --manage /dev/mdX --add /dev/sdYY which issues ioctl(ADD_NEW_DISC with disc.state set to MD_DISK_CLUSTER_ADD) 2. Node 1 sends NEWDISK with uuid and slot number 3. Other nodes issue kobject_uevent_env with uuid and slot number (Steps 4,5 could be a udev rule) 4. In userspace, the node searches for the disk, perhaps using blkid -t SUB_UUID="" 5. Other nodes issue either of the following depending on whether the disk was found: ioctl(ADD_NEW_DISK with disc.state set to MD_DISK_CANDIDATE and disc.number set to slot number) ioctl(CLUSTERED_DISK_NACK) 6. Other nodes drop lock on no-new-devs (CR) if device is found 7. Node 1 attempts EX lock on no-new-devs 8. If node 1 gets the lock, it sends METADATA_UPDATED after unmarking the disk as SpareLocal 9. If not (get no-new-dev lock), it fails the operation and sends METADATA_UPDATED 10. Other nodes understand if the device is added or not by reading the superblock again after receiving the METADATA_UPDATED message.
Showing the changes to include/uapi/linux/raid (2 of 7 files). Show all
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| @@ -78,6 +78,12 @@ · 77 unmodified lines | ||
| 78 | 78 | #define MD_DISK_ACTIVE 1 /* disk is running or spare disk */ |
| 79 | 79 | #define MD_DISK_SYNC 2 /* disk is in sync with the raid set */ |
| 80 | 80 | #define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */ |
| 81 | +#define MD_DISK_CLUSTER_ADD 4 /* Initiate a disk add across the cluster | |
| 82 | + * For clustered enviroments only. | |
| 83 | + */ | |
| 84 | +#define MD_DISK_CANDIDATE 5 /* disk is added as spare (local) until confirmed | |
| 85 | + * For clustered enviroments only. | |
| 86 | + */ | |
| 81 | 87 | |
| 82 | 88 | #define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config. |
| 83 | 89 | * read requests will only be sent here in |
| @@ -62,6 +62,7 @@ · 61 unmodified lines | ||
| 62 | 62 | #define STOP_ARRAY _IO (MD_MAJOR, 0x32) |
| 63 | 63 | #define STOP_ARRAY_RO _IO (MD_MAJOR, 0x33) |
| 64 | 64 | #define RESTART_ARRAY_RW _IO (MD_MAJOR, 0x34) |
| 65 | +#define CLUSTERED_DISK_NACK _IO (MD_MAJOR, 0x35) | |
| 65 | 66 | |
| 66 | 67 | /* 63 partitions with the alternate major number (mdp) */ |
| 67 | 68 | #define MdpMinorShift 6 |