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
pcm_oss.h
#ifndef __SOUND_PCM_OSS_H
#define __SOUND_PCM_OSS_H

/*
 *  Digital Audio (PCM) - OSS compatibility abstract layer
 *  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
 *
 */

struct snd_pcm_oss_setup {
	char *task_name;
	unsigned int disable:1,
		     direct:1,
		     block:1,
		     nonblock:1,
		     partialfrag:1,
		     nosilence:1,
		     buggyptr:1;
	unsigned int periods;
	unsigned int period_size;
	struct snd_pcm_oss_setup *next;
};

struct snd_pcm_oss_runtime {
	unsigned params: 1,			/* format/parameter change */
		 prepare: 1,			/* need to prepare the operation */
		 trigger: 1,			/* trigger flag */
		 sync_trigger: 1;		/* sync trigger flag */
	int rate;				/* requested rate */
	int format;				/* requested OSS format */
	unsigned int channels;			/* requested channels */
	unsigned int fragshift;
	unsigned int maxfrags;
	unsigned int subdivision;		/* requested subdivision */
	size_t period_bytes;			/* requested period size */
	size_t period_frames;			/* period frames for poll */
	size_t period_ptr;			/* actual write pointer to period */
	unsigned int periods;
	size_t buffer_bytes;			/* requested buffer size */
	size_t bytes;				/* total # bytes processed */
	size_t mmap_bytes;
	char *buffer;				/* vmallocated period */
	size_t buffer_used;			/* used length from period buffer */
	struct mutex params_lock;
#ifdef CONFIG_SND_PCM_OSS_PLUGINS
	struct snd_pcm_plugin *plugin_first;
	struct snd_pcm_plugin *plugin_last;
#endif
	unsigned int prev_hw_ptr_period;
};

struct snd_pcm_oss_file {
	struct snd_pcm_substream *streams[2];
};

struct snd_pcm_oss_substream {
	unsigned oss: 1;			/* oss mode */
	struct snd_pcm_oss_setup setup;		/* active setup */
};

struct snd_pcm_oss_stream {
	struct snd_pcm_oss_setup *setup_list;	/* setup list */
	struct mutex setup_mutex;
#ifdef CONFIG_SND_VERBOSE_PROCFS
	struct snd_info_entry *proc_entry;
#endif
};

struct snd_pcm_oss {
	int reg;
	unsigned int reg_mask;
};

#endif /* __SOUND_PCM_OSS_H */
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