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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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b5470dc5fc
md_allow_write() marks the metadata dirty while holding mddev->lock and then waits for the write to complete. For externally managed metadata this causes a deadlock as userspace needs to take the lock to communicate that the metadata update has completed. Change md_allow_write() in the 'external' case to start the 'mark active' operation and then return -EAGAIN. The expected side effects while waiting for userspace to write 'active' to 'array_state' are holding off reshape (code currently handles -ENOMEM), cause some 'stripe_cache_size' change requests to fail, cause some GET_BITMAP_FILE ioctl requests to fall back to GFP_NOIO, and cause updates to 'raid_disks' to fail. Except for 'stripe_cache_size' changes these failures can be mitigated by coordinating with mdmon. md_write_start() still prevents writes from occurring until the metadata handler has had a chance to take action as it unconditionally waits for MD_CHANGE_CLEAN to be cleared. [neilb@suse.de: return -EAGAIN, try GFP_NOIO] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
104 lines
3.4 KiB
C
104 lines
3.4 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 <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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#ifdef CONFIG_MD
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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 mdp_major;
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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_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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extern void md_do_sync(mddev_t *mddev);
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extern void md_new_event(mddev_t *mddev);
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extern int md_allow_write(mddev_t *mddev);
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extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
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#endif /* CONFIG_MD */
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#endif
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