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23 October 2021, 00:29:24 UTC
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 
dm thin: commit metadata before creating metadata snapshot
 
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
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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
tlv.h 
#ifndef __SOUND_TLV_H
#define __SOUND_TLV_H

/*
 *  Advanced Linux Sound Architecture - ALSA - Driver
 *  Copyright (c) 2006 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
 *
 */

/*
 * TLV structure is right behind the struct snd_ctl_tlv:
 *   unsigned int type  	- see SNDRV_CTL_TLVT_*
 *   unsigned int length
 *   .... data aligned to sizeof(unsigned int), use
 *        block_length = (length + (sizeof(unsigned int) - 1)) &
 *                       ~(sizeof(unsigned int) - 1)) ....
 */

#define SNDRV_CTL_TLVT_CONTAINER 0	/* one level down - group of TLVs */
#define SNDRV_CTL_TLVT_DB_SCALE	1       /* dB scale */
#define SNDRV_CTL_TLVT_DB_LINEAR 2	/* linear volume */
#define SNDRV_CTL_TLVT_DB_RANGE 3	/* dB range container */
#define SNDRV_CTL_TLVT_DB_MINMAX 4	/* dB scale with min/max */
#define SNDRV_CTL_TLVT_DB_MINMAX_MUTE 5	/* dB scale with min/max with mute */

#define TLV_DB_SCALE_MASK	0xffff
#define TLV_DB_SCALE_MUTE	0x10000
#define TLV_DB_SCALE_ITEM(min, step, mute)			\
	SNDRV_CTL_TLVT_DB_SCALE, 2 * sizeof(unsigned int),	\
	(min), ((step) & TLV_DB_SCALE_MASK) | ((mute) ? TLV_DB_SCALE_MUTE : 0)
#define DECLARE_TLV_DB_SCALE(name, min, step, mute) \
	unsigned int name[] = { TLV_DB_SCALE_ITEM(min, step, mute) }

/* dB scale specified with min/max values instead of step */
#define TLV_DB_MINMAX_ITEM(min_dB, max_dB)			\
	SNDRV_CTL_TLVT_DB_MINMAX, 2 * sizeof(unsigned int),	\
	(min_dB), (max_dB)
#define TLV_DB_MINMAX_MUTE_ITEM(min_dB, max_dB)			\
	SNDRV_CTL_TLVT_DB_MINMAX_MUTE, 2 * sizeof(unsigned int),	\
	(min_dB), (max_dB)
#define DECLARE_TLV_DB_MINMAX(name, min_dB, max_dB) \
	unsigned int name[] = { TLV_DB_MINMAX_ITEM(min_dB, max_dB) }
#define DECLARE_TLV_DB_MINMAX_MUTE(name, min_dB, max_dB) \
	unsigned int name[] = { TLV_DB_MINMAX_MUTE_ITEM(min_dB, max_dB) }

/* linear volume between min_dB and max_dB (.01dB unit) */
#define TLV_DB_LINEAR_ITEM(min_dB, max_dB)		    \
	SNDRV_CTL_TLVT_DB_LINEAR, 2 * sizeof(unsigned int), \
	(min_dB), (max_dB)
#define DECLARE_TLV_DB_LINEAR(name, min_dB, max_dB)	\
	unsigned int name[] = { TLV_DB_LINEAR_ITEM(min_dB, max_dB) }

/* dB range container */
/* Each item is: <min> <max> <TLV> */
/* The below assumes that each item TLV is 4 words like DB_SCALE or LINEAR */
#define TLV_DB_RANGE_HEAD(num)			\
	SNDRV_CTL_TLVT_DB_RANGE, 6 * (num) * sizeof(unsigned int)

#define TLV_DB_GAIN_MUTE	-9999999

#endif /* __SOUND_TLV_H */
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