2604b703b6
md supports multiple different RAID level, each being implemented by a
'personality' (which is often in a separate module).
These personalities have fairly artificial 'numbers'. The numbers
are use to:
1- provide an index into an array where the various personalities
are recorded
2- identify the module (via an alias) which implements are particular
personality.
Neither of these uses really justify the existence of personality numbers.
The array can be replaced by a linked list which is searched (array lookup
only happens very rarely). Module identification can be done using an alias
based on level rather than 'personality' number.
The current 'raid5' modules support two level (4 and 5) but only one
personality. This slight awkwardness (which was handled in the mapping from
level to personality) can be better handled by allowing raid5 to register 2
personalities.
With this change in place, the core md module does not need to have an
exhaustive list of all possible personalities, so other personalities can be
added independently.
This patch also moves the check for chunksize being non-zero into the ->run
routines for the personalities that need it, rather than having it in core-md.
This has a side effect of allowing 'faulty' and 'linear' not to have a
chunk-size set.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
100 lines
3.3 KiB
C
100 lines
3.3 KiB
C
/*
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md.h : Multiple Devices driver for Linux
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Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
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Copyright (C) 1994-96 Marc ZYNGIER
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<zyngier@ufr-info-p7.ibp.fr> or
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<maz@gloups.fdn.fr>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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You should have received a copy of the GNU General Public License
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(for example /usr/src/linux/COPYING); if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef _MD_H
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#define _MD_H
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#include <linux/blkdev.h>
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#include <asm/semaphore.h>
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#include <linux/major.h>
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#include <linux/ioctl.h>
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#include <linux/types.h>
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#include <linux/bitops.h>
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#include <linux/module.h>
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#include <linux/hdreg.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/smp_lock.h>
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#include <linux/delay.h>
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#include <net/checksum.h>
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#include <linux/random.h>
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#include <linux/kernel_stat.h>
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#include <asm/io.h>
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#include <linux/completion.h>
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#include <linux/mempool.h>
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#include <linux/list.h>
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#include <linux/reboot.h>
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#include <linux/vmalloc.h>
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#include <linux/blkpg.h>
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#include <linux/bio.h>
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/*
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* 'md_p.h' holds the 'physical' layout of RAID devices
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* 'md_u.h' holds the user <=> kernel API
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*
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* 'md_k.h' holds kernel internal definitions
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*/
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#include <linux/raid/md_p.h>
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#include <linux/raid/md_u.h>
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#include <linux/raid/md_k.h>
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/*
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* Different major versions are not compatible.
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* Different minor versions are only downward compatible.
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* Different patchlevel versions are downward and upward compatible.
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*/
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#define MD_MAJOR_VERSION 0
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#define MD_MINOR_VERSION 90
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/*
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* MD_PATCHLEVEL_VERSION indicates kernel functionality.
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* >=1 means different superblock formats are selectable using SET_ARRAY_INFO
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* and major_version/minor_version accordingly
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* >=2 means that Internal bitmaps are supported by setting MD_SB_BITMAP_PRESENT
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* in the super status byte
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* >=3 means that bitmap superblock version 4 is supported, which uses
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* little-ending representation rather than host-endian
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*/
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#define MD_PATCHLEVEL_VERSION 3
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extern int register_md_personality (struct mdk_personality *p);
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extern int unregister_md_personality (struct mdk_personality *p);
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extern mdk_thread_t * md_register_thread (void (*run) (mddev_t *mddev),
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mddev_t *mddev, const char *name);
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extern void md_unregister_thread (mdk_thread_t *thread);
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extern void md_wakeup_thread(mdk_thread_t *thread);
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extern void md_check_recovery(mddev_t *mddev);
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extern void md_write_start(mddev_t *mddev, struct bio *bi);
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extern void md_write_end(mddev_t *mddev);
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extern void md_handle_safemode(mddev_t *mddev);
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extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
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extern void md_error (mddev_t *mddev, mdk_rdev_t *rdev);
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extern void md_unplug_mddev(mddev_t *mddev);
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extern void md_print_devices (void);
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extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
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sector_t sector, int size, struct page *page);
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extern void md_super_wait(mddev_t *mddev);
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extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
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struct page *page, int rw);
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#define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
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#endif
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