/* md.h : Multiple Devices driver for Linux Copyright (C) 1994-96 Marc ZYNGIER or This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. You should have received a copy of the GNU General Public License (for example /usr/src/linux/COPYING); if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #ifndef _MD_H #define _MD_H #include #include #include /* * Different major versions are not compatible. * Different minor versions are only downward compatible. * Different patchlevel versions are downward and upward compatible. */ #define MD_MAJOR_VERSION 0 #define MD_MINOR_VERSION 36 #define MD_PATCHLEVEL_VERSION 6 #define MD_DEFAULT_DISK_READAHEAD (256 * 1024) /* ioctls */ #define REGISTER_DEV _IO (MD_MAJOR, 1) #define START_MD _IO (MD_MAJOR, 2) #define STOP_MD _IO (MD_MAJOR, 3) #define REGISTER_DEV_NEW _IO (MD_MAJOR, 4) /* personalities : Byte 0 : Chunk size factor Byte 1 : Fault tolerance count for each physical device ( 0 means no fault tolerance, 0xFF means always tolerate faults), not used by now. Byte 2 : Personality Byte 3 : Reserved. */ #define FAULT_SHIFT 8 #define PERSONALITY_SHIFT 16 #define FACTOR_MASK 0x000000FFUL #define FAULT_MASK 0x0000FF00UL #define PERSONALITY_MASK 0x00FF0000UL #define MD_RESERVED 0 /* Not used by now */ #define LINEAR (1UL << PERSONALITY_SHIFT) #define STRIPED (2UL << PERSONALITY_SHIFT) #define RAID0 STRIPED #define RAID1 (3UL << PERSONALITY_SHIFT) #define RAID5 (4UL << PERSONALITY_SHIFT) #define MAX_PERSONALITY 5 /* * MD superblock. * * The MD superblock maintains some statistics on each MD configuration. * Each real device in the MD set contains it near the end of the device. * Some of the ideas are copied from the ext2fs implementation. * * We currently use 4096 bytes as follows: * * word offset function * * 0 - 31 Constant generic MD device information. * 32 - 63 Generic state information. * 64 - 127 Personality specific information. * 128 - 511 12 32-words descriptors of the disks in the raid set. * 512 - 911 Reserved. * 912 - 1023 Disk specific descriptor. */ /* * If x is the real device size in bytes, we return an apparent size of: * * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES * * and place the 4kB superblock at offset y. */ #define MD_RESERVED_BYTES (64 * 1024) #define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) #define MD_RESERVED_BLOCKS (MD_RESERVED_BYTES / BLOCK_SIZE) #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) #define MD_NEW_SIZE_BLOCKS(x) ((x & ~(MD_RESERVED_BLOCKS - 1)) - MD_RESERVED_BLOCKS) #define MD_SB_BYTES 4096 #define MD_SB_WORDS (MD_SB_BYTES / 4) #define MD_SB_BLOCKS (MD_SB_BYTES / BLOCK_SIZE) #define MD_SB_SECTORS (MD_SB_BYTES / 512) /* * The following are counted in 32-bit words */ #define MD_SB_GENERIC_OFFSET 0 #define MD_SB_PERSONALITY_OFFSET 64 #define MD_SB_DISKS_OFFSET 128 #define MD_SB_DESCRIPTOR_OFFSET 992 #define MD_SB_GENERIC_CONSTANT_WORDS 32 #define MD_SB_GENERIC_STATE_WORDS 32 #define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS) #define MD_SB_PERSONALITY_WORDS 64 #define MD_SB_DISKS_WORDS 384 #define MD_SB_DESCRIPTOR_WORDS 32 #define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS) #define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS) #define MD_SB_DISKS (MD_SB_DISKS_WORDS / MD_SB_DESCRIPTOR_WORDS) /* * Device "operational" state bits */ #define MD_FAULTY_DEVICE 0 /* Device is faulty / operational */ #define MD_ACTIVE_DEVICE 1 /* Device is a part or the raid set / spare disk */ #define MD_SYNC_DEVICE 2 /* Device is in sync with the raid set */ typedef struct md_device_descriptor_s { __u32 number; /* 0 Device number in the entire set */ __u32 major; /* 1 Device major number */ __u32 minor; /* 2 Device minor number */ __u32 raid_disk; /* 3 The role of the device in the raid set */ __u32 state; /* 4 Operational state */ __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; } md_descriptor_t; #define MD_SB_MAGIC 0xa92b4efc /* * Superblock state bits */ #define MD_SB_CLEAN 0 #define MD_SB_ERRORS 1 typedef struct md_superblock_s { /* * Constant generic information */ __u32 md_magic; /* 0 MD identifier */ __u32 major_version; /* 1 major version to which the set conforms */ __u32 minor_version; /* 2 minor version to which the set conforms */ __u32 patch_version; /* 3 patchlevel version to which the set conforms */ __u32 gvalid_words; /* 4 Number of non-reserved words in this section */ __u32 set_magic; /* 5 Raid set identifier */ __u32 ctime; /* 6 Creation time */ __u32 level; /* 7 Raid personality (mirroring, raid5, ...) */ __u32 size; /* 8 Apparent size of each individual disk, in kB */ __u32 nr_disks; /* 9 Number of total disks in the raid set */ __u32 raid_disks; /* 10 Number of disks in a fully functional raid set */ __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 11]; /* * Generic state information */ __u32 utime; /* 0 Superblock update time */ __u32 state; /* 1 State bits (clean, ...) */ __u32 active_disks; /* 2 Number of currently active disks (some non-faulty disks might not be in sync) */ __u32 working_disks; /* 3 Number of working disks */ __u32 failed_disks; /* 4 Number of failed disks */ __u32 spare_disks; /* 5 Number of spare disks */ __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 6]; /* * Personality information */ __u32 parity_algorithm; __u32 chunk_size; __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 2]; /* * Disks information */ md_descriptor_t disks[MD_SB_DISKS]; /* * Reserved */ __u32 reserved[MD_SB_RESERVED_WORDS]; /* * Active descriptor */ md_descriptor_t descriptor; } md_superblock_t; #ifdef __KERNEL__ #include #include #include #include /* * Kernel-based reconstruction is mostly working, but still requires * some additional work. */ #define SUPPORT_RECONSTRUCTION 0 #define MAX_REAL 8 /* Max number of physical dev per md dev */ #define MAX_MD_DEV 4 /* Max number of md dev */ #define FACTOR(a) ((a)->repartition & FACTOR_MASK) #define MAX_FAULT(a) (((a)->repartition & FAULT_MASK)>>8) #define PERSONALITY(a) ((a)->repartition & PERSONALITY_MASK) #define FACTOR_SHIFT(a) (PAGE_SHIFT + (a) - 10) struct real_dev { kdev_t dev; /* Device number */ int size; /* Device size (in blocks) */ int offset; /* Real device offset (in blocks) in md dev (only used in linear mode) */ struct inode *inode; /* Lock inode */ md_superblock_t *sb; u32 sb_offset; }; struct md_dev; #define SPARE_INACTIVE 0 #define SPARE_WRITE 1 #define SPARE_ACTIVE 2 struct md_personality { char *name; int (*map)(struct md_dev *mddev, kdev_t *rdev, unsigned long *rsector, unsigned long size); int (*make_request)(struct md_dev *mddev, int rw, struct buffer_head * bh); void (*end_request)(struct buffer_head * bh, int uptodate); int (*run)(int minor, struct md_dev *mddev); int (*stop)(int minor, struct md_dev *mddev); int (*status)(char *page, int minor, struct md_dev *mddev); int (*ioctl)(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg); int max_invalid_dev; int (*error_handler)(struct md_dev *mddev, kdev_t dev); /* * Some personalities (RAID-1, RAID-5) can get disks hot-added and * hot-removed. Hot removal is different from failure. (failure marks * a disk inactive, but the disk is still part of the array) */ int (*hot_add_disk) (struct md_dev *mddev, kdev_t dev); int (*hot_remove_disk) (struct md_dev *mddev, kdev_t dev); int (*mark_spare) (struct md_dev *mddev, md_descriptor_t *descriptor, int state); }; struct md_dev { struct real_dev devices[MAX_REAL]; struct md_personality *pers; md_superblock_t *sb; int sb_dirty; int repartition; int busy; int nb_dev; void *private; }; struct md_thread { void (*run) (void *data); void *data; struct wait_queue *wqueue; unsigned long flags; struct semaphore *sem; struct task_struct *tsk; }; #define THREAD_WAKEUP 0 extern struct md_dev md_dev[MAX_MD_DEV]; extern int md_size[MAX_MD_DEV]; extern int md_maxreadahead[MAX_MD_DEV]; extern char *partition_name (kdev_t dev); extern int register_md_personality (int p_num, struct md_personality *p); extern int unregister_md_personality (int p_num); extern struct md_thread *md_register_thread (void (*run) (void *data), void *data); extern void md_unregister_thread (struct md_thread *thread); extern void md_wakeup_thread(struct md_thread *thread); extern int md_update_sb (int minor); extern int md_do_sync(struct md_dev *mddev); #endif __KERNEL__ #endif _MD_H