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
Tip revision: 0d200aefd4ac51787b6b80de1bb7ce93bccd59f6 authored by Joe Thornber on 03 July 2012, 11:55:31 UTC
dm thin: commit metadata before creating metadata snapshot
dm thin: commit metadata before creating metadata snapshot
Tip revision: 0d200ae
seq_device.h
#ifndef __SOUND_SEQ_DEVICE_H
#define __SOUND_SEQ_DEVICE_H
/*
* ALSA sequencer device management
* Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
*
* 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
*
*/
/*
* registered device information
*/
#define ID_LEN 32
/* status flag */
#define SNDRV_SEQ_DEVICE_FREE 0
#define SNDRV_SEQ_DEVICE_REGISTERED 1
struct snd_seq_device {
/* device info */
struct snd_card *card; /* sound card */
int device; /* device number */
char id[ID_LEN]; /* driver id */
char name[80]; /* device name */
int argsize; /* size of the argument */
void *driver_data; /* private data for driver */
int status; /* flag - read only */
void *private_data; /* private data for the caller */
void (*private_free)(struct snd_seq_device *device);
struct list_head list; /* link to next device */
};
/* driver operators
* init_device:
* Initialize the device with given parameters.
* Typically,
* 1. call snd_hwdep_new
* 2. allocate private data and initialize it
* 3. call snd_hwdep_register
* 4. store the instance to dev->driver_data pointer.
*
* free_device:
* Release the private data.
* Typically, call snd_device_free(dev->card, dev->driver_data)
*/
struct snd_seq_dev_ops {
int (*init_device)(struct snd_seq_device *dev);
int (*free_device)(struct snd_seq_device *dev);
};
/*
* prototypes
*/
void snd_seq_device_load_drivers(void);
int snd_seq_device_new(struct snd_card *card, int device, char *id, int argsize, struct snd_seq_device **result);
int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry, int argsize);
int snd_seq_device_unregister_driver(char *id);
#define SNDRV_SEQ_DEVICE_ARGPTR(dev) (void *)((char *)(dev) + sizeof(struct snd_seq_device))
/*
* id strings for generic devices
*/
#define SNDRV_SEQ_DEV_ID_MIDISYNTH "seq-midi"
#define SNDRV_SEQ_DEV_ID_OPL3 "opl3-synth"
#endif /* __SOUND_SEQ_DEVICE_H */
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