The structure “struct md_personality” is the one which contains information about a RAID level. It is defined in md.h . You’ll find below some explanations about each member of the structure.<\/p>\n
[code lang=”c”]<\/p>\n
\r\nchar *name; \/\/Name of the level\r\nint level; \/\/Number related to the level, negative level are for \"special one\", for example the linear level is -1\r\nstruct list_head l i s t ; \/\/Linked list of all MD personnalities.\r\nstruct module *owner; \/\/Pointer to the Linux module managing this level\r\n\r\n\/\u2217* Do a block I\/O operation\r\n * @param mddev structure representing the array\r\n * @param bio Bock I\/O representing the operation to do\r\n *\/\r\nvoid (*make_request)(struct mddev *mddev, struct bio* bio);\r\n\r\n\/** Build and assemble a RAID array\r\n * @param mddev structure representing the array\r\n *\/\r\nint (*run)(struct mddev *mddev);\r\n\r\n\/** Disassemble an array\r\n * @param mddev structure representing the array\r\n *\/\r\nint (*stop)(struct mddev *mddev);\r\n\r\n\/** Write some status informations to a file\r\n * @param seq virtual file\r\n * @param mddev structure representing the array\r\n *\/\r\nvoid (*status)(struct seq_file *seq, struct mddev *mddev);\r\n\r\n\/** Function called when an error occur in the MD subsystem.\r\n * The usual way to run it is to call md_error() inside a md module, which will set some flags and start the recovery thread, and call this error_handler\r\n * @param mddev structure representing the array\r\n * @param rdev The physical drive responsible for the failure if applicable\r\nvoid (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);\r\n\r\n\/** Add a disk while the array is still running\r\n * @param mddev structure representing the array\r\n * @param rdev the physical disk to add\r\n *\/\r\nint (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);\r\n\r\n\/** Remove a disk while the array is still running\r\n * @param mddev structure representing the array\r\n * @param number index of the disk to remove\r\n *\/\r\nint (*hot_remove_disk) (struct mddev *mddev, int number);\r\n\r\n\/** Return the number of active spare drive.\r\n * @param mddev structure representing the array\r\n *\/\r\nint (*spare_active) (struct mddev *mddev);\r\n\r\n\/** Handle a re-synchronization request for some sector\r\n * @param mddev structure representing the array\r\n * @param sector_nr Sector to synchronize\r\n * @param skipped Will be set to 1 if the sync was skipped\r\n * @param go_faster If false, will sleep interruptible to throttle resync\r\n *\/ \r\nsector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster);\r\n\r\n\/** Resize an array\r\n * @param mddev structure representing the array\r\n * @param sectors new size\r\n *\/\r\nint (*resize) (struct mddev *mddev, sector_t sectors);\r\n\r\n\/** Return the size of the array. If sectors and raid_disks are not zero, size is computed using those numbers instead of the real ones.\r\n *\/\r\nsector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);\r\n\r\n\/** Check_reshape Reshape an array after adding or removing some disks\r\n *\/\r\nint (*check_reshape) (struct mddev *mddev);\r\n\r\n\/\/ unused\r\nint (*start_reshape) (struct mddev *mddev);\r\nvoid (*finish_reshape) (struct mddev *mddev);\r\n\r\n\/** quiesce moves between quiescence states\r\n * 0 - fully active\r\n * 1 - no new requests allowed\r\n * others - reserved\r\n *\/\r\nvoid (*quiesce) (struct mddev *mddev, int state);\r\n\r\n\/** takeover is used to transition an array from one\r\n * personality to another. The new personality must be able\r\n * to handle the data in the current layout.\r\n * e.g. 2drive raid1 -> 2drive raid5\r\n * ndrive raid5 -> degraded n+1drive raid6 with special layout\r\n * If the takeover succeeds, a new 'private' structure is returned.\r\n * This needs to be installed and then ->run used to activate the\r\n * array.\r\n *\/\r\nvoid *(*takeover) (struct mddev *mddev);\r\n\r\n<\/pre>\n[\/code]<\/p>\n","protected":false},"excerpt":{"rendered":"
The structure “struct md_personality” is the one which contains information about a RAID level. It is defined in md.h . You’ll find below some explanations about each member of the structure. [code lang=”c”] char *name; \/\/Name of the level int level; \/\/Number related to the level, negative level are for “special one”, for example the … <\/p>\n