https://github.com/torvalds/linux
Revision 0d200aefd4ac51787b6b80de1bb7ce93bccd59f6 authored by Joe Thornber on 03 July 2012, 11:55:31 UTC, committed by Alasdair G Kergon on 03 July 2012, 11:55:31 UTC
Userland sometimes sees a corrupt metadata block if metadata is changing
rapidly when a metadata snapshot is reserved for userland,  To make the
problem go away, commit before we take the metadata snapshot (which is a
sensible thing to do anyway).

The checksums mean userland spots this corruption immediately so there's
no risk of acting on incorrect data.  No corruption exists from the
kernel's point of view, and thin_check passes after pool shutdown.

I believe this is to do with shared blocks at the first level of the
{device, mapping} btree.  Prior to the metadata-snap support no sharing
at this level was possible, so this patch is only required after commit
cc8394d86f045b86ff303d3c9e4ce47d97148951 ("dm thin: provide userspace
access to pool metadata").

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 parent 6887a41
Raw File
Tip revision: 0d200aefd4ac51787b6b80de1bb7ce93bccd59f6 authored by Joe Thornber on 03 July 2012, 11:55:31 UTC
dm thin: commit metadata before creating metadata snapshot
Tip revision: 0d200ae
control.h
#ifndef __SOUND_CONTROL_H
#define __SOUND_CONTROL_H

/*
 *  Header file for control interface
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   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 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/asound.h>

#define snd_kcontrol_chip(kcontrol) ((kcontrol)->private_data)

struct snd_kcontrol;
typedef int (snd_kcontrol_info_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_info * uinfo);
typedef int (snd_kcontrol_get_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_value * ucontrol);
typedef int (snd_kcontrol_put_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_value * ucontrol);
typedef int (snd_kcontrol_tlv_rw_t)(struct snd_kcontrol *kcontrol,
				    int op_flag, /* 0=read,1=write,-1=command */
				    unsigned int size,
				    unsigned int __user *tlv);


struct snd_kcontrol_new {
	snd_ctl_elem_iface_t iface;	/* interface identifier */
	unsigned int device;		/* device/client number */
	unsigned int subdevice;		/* subdevice (substream) number */
	const unsigned char *name;	/* ASCII name of item */
	unsigned int index;		/* index of item */
	unsigned int access;		/* access rights */
	unsigned int count;		/* count of same elements */
	snd_kcontrol_info_t *info;
	snd_kcontrol_get_t *get;
	snd_kcontrol_put_t *put;
	union {
		snd_kcontrol_tlv_rw_t *c;
		const unsigned int *p;
	} tlv;
	unsigned long private_value;
};

struct snd_kcontrol_volatile {
	struct snd_ctl_file *owner;	/* locked */
	unsigned int access;	/* access rights */
};

struct snd_kcontrol {
	struct list_head list;		/* list of controls */
	struct snd_ctl_elem_id id;
	unsigned int count;		/* count of same elements */
	snd_kcontrol_info_t *info;
	snd_kcontrol_get_t *get;
	snd_kcontrol_put_t *put;
	union {
		snd_kcontrol_tlv_rw_t *c;
		const unsigned int *p;
	} tlv;
	unsigned long private_value;
	void *private_data;
	void (*private_free)(struct snd_kcontrol *kcontrol);
	struct snd_kcontrol_volatile vd[0];	/* volatile data */
};

#define snd_kcontrol(n) list_entry(n, struct snd_kcontrol, list)

struct snd_kctl_event {
	struct list_head list;	/* list of events */
	struct snd_ctl_elem_id id;
	unsigned int mask;
};

#define snd_kctl_event(n) list_entry(n, struct snd_kctl_event, list)

struct pid;

struct snd_ctl_file {
	struct list_head list;		/* list of all control files */
	struct snd_card *card;
	struct pid *pid;
	int prefer_pcm_subdevice;
	int prefer_rawmidi_subdevice;
	wait_queue_head_t change_sleep;
	spinlock_t read_lock;
	struct fasync_struct *fasync;
	int subscribed;			/* read interface is activated */
	struct list_head events;	/* waiting events for read */
};

#define snd_ctl_file(n) list_entry(n, struct snd_ctl_file, list)

typedef int (*snd_kctl_ioctl_func_t) (struct snd_card * card,
				      struct snd_ctl_file * control,
				      unsigned int cmd, unsigned long arg);

void snd_ctl_notify(struct snd_card * card, unsigned int mask, struct snd_ctl_elem_id * id);

struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new * kcontrolnew, void * private_data);
void snd_ctl_free_one(struct snd_kcontrol * kcontrol);
int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol);
int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);
int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, bool add_on_replace);
int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);
int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);
int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
			int active);
struct snd_kcontrol *snd_ctl_find_numid(struct snd_card * card, unsigned int numid);
struct snd_kcontrol *snd_ctl_find_id(struct snd_card * card, struct snd_ctl_elem_id *id);

int snd_ctl_create(struct snd_card *card);

int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn);
int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn);
#ifdef CONFIG_COMPAT
int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn);
int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn);
#else
#define snd_ctl_register_ioctl_compat(fcn)
#define snd_ctl_unregister_ioctl_compat(fcn)
#endif

static inline unsigned int snd_ctl_get_ioffnum(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)
{
	return id->numid - kctl->id.numid;
}

static inline unsigned int snd_ctl_get_ioffidx(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)
{
	return id->index - kctl->id.index;
}

static inline unsigned int snd_ctl_get_ioff(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)
{
	if (id->numid) {
		return snd_ctl_get_ioffnum(kctl, id);
	} else {
		return snd_ctl_get_ioffidx(kctl, id);
	}
}

static inline struct snd_ctl_elem_id *snd_ctl_build_ioff(struct snd_ctl_elem_id *dst_id,
						    struct snd_kcontrol *src_kctl,
						    unsigned int offset)
{
	*dst_id = src_kctl->id;
	dst_id->index += offset;
	dst_id->numid += offset;
	return dst_id;
}

/*
 * Frequently used control callbacks/helpers
 */
int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
			      struct snd_ctl_elem_info *uinfo);
int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
				struct snd_ctl_elem_info *uinfo);
int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
		      unsigned int items, const char *const names[]);

/*
 * virtual master control
 */
struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
						 const unsigned int *tlv);
int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
		       unsigned int flags);
/* optional flags for slave */
#define SND_CTL_SLAVE_NEED_UPDATE	(1 << 0)

/**
 * snd_ctl_add_slave - Add a virtual slave control
 * @master: vmaster element
 * @slave: slave element to add
 *
 * Add a virtual slave control to the given master element created via
 * snd_ctl_create_virtual_master() beforehand.
 * Returns zero if successful or a negative error code.
 *
 * All slaves must be the same type (returning the same information
 * via info callback).  The function doesn't check it, so it's your
 * responsibility.
 *
 * Also, some additional limitations:
 * at most two channels,
 * logarithmic volume control (dB level) thus no linear volume,
 * master can only attenuate the volume without gain
 */
static inline int
snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave)
{
	return _snd_ctl_add_slave(master, slave, 0);
}

/**
 * snd_ctl_add_slave_uncached - Add a virtual slave control
 * @master: vmaster element
 * @slave: slave element to add
 *
 * Add a virtual slave control to the given master.
 * Unlike snd_ctl_add_slave(), the element added via this function
 * is supposed to have volatile values, and get callback is called
 * at each time quried from the master.
 *
 * When the control peeks the hardware values directly and the value
 * can be changed by other means than the put callback of the element,
 * this function should be used to keep the value always up-to-date.
 */
static inline int
snd_ctl_add_slave_uncached(struct snd_kcontrol *master,
			   struct snd_kcontrol *slave)
{
	return _snd_ctl_add_slave(master, slave, SND_CTL_SLAVE_NEED_UPDATE);
}

int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kctl,
			     void (*hook)(void *private_data, int),
			     void *private_data);
void snd_ctl_sync_vmaster_hook(struct snd_kcontrol *kctl);

/*
 * Helper functions for jack-detection controls
 */
struct snd_kcontrol *
snd_kctl_jack_new(const char *name, int idx, void *private_data);
void snd_kctl_jack_report(struct snd_card *card,
			  struct snd_kcontrol *kctl, bool status);

#endif	/* __SOUND_CONTROL_H */
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