5c6bd75d06
If you misuse the device-mapper interface (or there's a bug in your userspace tools) it's possible to end up with 'unlinked' mapped devices that cannot be removed until you reboot (along with uninterruptible processes). This patch prevents you from removing a device that is still open. It introduces dm_lock_for_deletion() which is called when a device is about to be removed to ensure that nothing has it open and nothing further can open it. It uses a private open_count for this which also lets us remove one of the problematic bdget_disk() calls elsewhere. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
130 lines
3.5 KiB
C
130 lines
3.5 KiB
C
/*
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* Internal header file for device mapper
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*
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* Copyright (C) 2001, 2002 Sistina Software
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef DM_INTERNAL_H
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#define DM_INTERNAL_H
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#include <linux/fs.h>
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#include <linux/device-mapper.h>
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#include <linux/list.h>
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#include <linux/blkdev.h>
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#include <linux/hdreg.h>
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#define DM_NAME "device-mapper"
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#define DMWARN(f, x...) printk(KERN_WARNING DM_NAME ": " f "\n" , ## x)
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#define DMERR(f, x...) printk(KERN_ERR DM_NAME ": " f "\n" , ## x)
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#define DMINFO(f, x...) printk(KERN_INFO DM_NAME ": " f "\n" , ## x)
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#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
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0 : scnprintf(result + sz, maxlen - sz, x))
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#define SECTOR_SHIFT 9
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/*
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* List of devices that a metadevice uses and should open/close.
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*/
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struct dm_dev {
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struct list_head list;
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atomic_t count;
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int mode;
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struct block_device *bdev;
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char name[16];
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};
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struct dm_table;
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/*-----------------------------------------------------------------
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* Internal table functions.
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*---------------------------------------------------------------*/
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void dm_table_event_callback(struct dm_table *t,
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void (*fn)(void *), void *context);
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struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
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struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
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void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q);
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struct list_head *dm_table_get_devices(struct dm_table *t);
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void dm_table_presuspend_targets(struct dm_table *t);
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void dm_table_postsuspend_targets(struct dm_table *t);
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void dm_table_resume_targets(struct dm_table *t);
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int dm_table_any_congested(struct dm_table *t, int bdi_bits);
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void dm_table_unplug_all(struct dm_table *t);
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int dm_table_flush_all(struct dm_table *t);
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/*-----------------------------------------------------------------
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* A registry of target types.
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*---------------------------------------------------------------*/
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int dm_target_init(void);
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void dm_target_exit(void);
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struct target_type *dm_get_target_type(const char *name);
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void dm_put_target_type(struct target_type *t);
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int dm_target_iterate(void (*iter_func)(struct target_type *tt,
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void *param), void *param);
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/*-----------------------------------------------------------------
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* Useful inlines.
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*---------------------------------------------------------------*/
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static inline int array_too_big(unsigned long fixed, unsigned long obj,
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unsigned long num)
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{
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return (num > (ULONG_MAX - fixed) / obj);
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}
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/*
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* Ceiling(n / sz)
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*/
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#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
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#define dm_sector_div_up(n, sz) ( \
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{ \
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sector_t _r = ((n) + (sz) - 1); \
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sector_div(_r, (sz)); \
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_r; \
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} \
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)
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/*
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* ceiling(n / size) * size
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*/
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#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
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static inline sector_t to_sector(unsigned long n)
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{
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return (n >> 9);
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}
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static inline unsigned long to_bytes(sector_t n)
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{
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return (n << 9);
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}
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int dm_split_args(int *argc, char ***argvp, char *input);
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/*
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* The device-mapper can be driven through one of two interfaces;
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* ioctl or filesystem, depending which patch you have applied.
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*/
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int dm_interface_init(void);
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void dm_interface_exit(void);
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/*
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* Targets for linear and striped mappings
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*/
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int dm_linear_init(void);
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void dm_linear_exit(void);
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int dm_stripe_init(void);
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void dm_stripe_exit(void);
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void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
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union map_info *dm_get_mapinfo(struct bio *bio);
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int dm_open_count(struct mapped_device *md);
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int dm_lock_for_deletion(struct mapped_device *md);
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#endif
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