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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
seq_midi_event.h 
#ifndef __SOUND_SEQ_MIDI_EVENT_H
#define __SOUND_SEQ_MIDI_EVENT_H

/*
 *  MIDI byte <-> sequencer event coder
 *
 *  Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>,
 *                        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 "asequencer.h"

#define MAX_MIDI_EVENT_BUF	256

/* midi status */
struct snd_midi_event {
	int qlen;		/* queue length */
	int read;		/* chars read */
	int type;		/* current event type */
	unsigned char lastcmd;	/* last command (for MIDI state handling) */
	unsigned char nostat;	/* no state flag */
	int bufsize;		/* allocated buffer size */
	unsigned char *buf;	/* input buffer */
	spinlock_t lock;
};

int snd_midi_event_new(int bufsize, struct snd_midi_event **rdev);
void snd_midi_event_free(struct snd_midi_event *dev);
void snd_midi_event_reset_encode(struct snd_midi_event *dev);
void snd_midi_event_reset_decode(struct snd_midi_event *dev);
void snd_midi_event_no_status(struct snd_midi_event *dev, int on);
/* encode from byte stream - return number of written bytes if success */
long snd_midi_event_encode(struct snd_midi_event *dev, unsigned char *buf, long count,
			   struct snd_seq_event *ev);
int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c, struct snd_seq_event *ev);
/* decode from event to bytes - return number of written bytes if success */
long snd_midi_event_decode(struct snd_midi_event *dev, unsigned char *buf, long count,
			   struct snd_seq_event *ev);

#endif /* __SOUND_SEQ_MIDI_EVENT_H */
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