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
info.h
#ifndef __SOUND_INFO_H
#define __SOUND_INFO_H

/*
 *  Header file for info 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 <linux/poll.h>

/* buffer for information */
struct snd_info_buffer {
	char *buffer;		/* pointer to begin of buffer */
	unsigned int curr;	/* current position in buffer */
	unsigned int size;	/* current size */
	unsigned int len;	/* total length of buffer */
	int stop;		/* stop flag */
	int error;		/* error code */
};

#define SNDRV_INFO_CONTENT_TEXT		0
#define SNDRV_INFO_CONTENT_DATA		1

struct snd_info_entry;

struct snd_info_entry_text {
	void (*read)(struct snd_info_entry *entry,
		     struct snd_info_buffer *buffer);
	void (*write)(struct snd_info_entry *entry,
		      struct snd_info_buffer *buffer);
};

struct snd_info_entry_ops {
	int (*open)(struct snd_info_entry *entry,
		    unsigned short mode, void **file_private_data);
	int (*release)(struct snd_info_entry *entry,
		       unsigned short mode, void *file_private_data);
	ssize_t (*read)(struct snd_info_entry *entry, void *file_private_data,
			struct file *file, char __user *buf,
			size_t count, loff_t pos);
	ssize_t (*write)(struct snd_info_entry *entry, void *file_private_data,
			 struct file *file, const char __user *buf,
			 size_t count, loff_t pos);
	loff_t (*llseek)(struct snd_info_entry *entry,
			 void *file_private_data, struct file *file,
			 loff_t offset, int orig);
	unsigned int (*poll)(struct snd_info_entry *entry,
			     void *file_private_data, struct file *file,
			     poll_table *wait);
	int (*ioctl)(struct snd_info_entry *entry, void *file_private_data,
		     struct file *file, unsigned int cmd, unsigned long arg);
	int (*mmap)(struct snd_info_entry *entry, void *file_private_data,
		    struct inode *inode, struct file *file,
		    struct vm_area_struct *vma);
};

struct snd_info_entry {
	const char *name;
	umode_t mode;
	long size;
	unsigned short content;
	union {
		struct snd_info_entry_text text;
		struct snd_info_entry_ops *ops;
	} c;
	struct snd_info_entry *parent;
	struct snd_card *card;
	struct module *module;
	void *private_data;
	void (*private_free)(struct snd_info_entry *entry);
	struct proc_dir_entry *p;
	struct mutex access;
	struct list_head children;
	struct list_head list;
};

#if defined(CONFIG_SND_OSSEMUL) && defined(CONFIG_PROC_FS)
int snd_info_minor_register(void);
int snd_info_minor_unregister(void);
#else
#define snd_info_minor_register() /* NOP */
#define snd_info_minor_unregister() /* NOP */
#endif


#ifdef CONFIG_PROC_FS

extern struct snd_info_entry *snd_seq_root;
#ifdef CONFIG_SND_OSSEMUL
extern struct snd_info_entry *snd_oss_root;
void snd_card_info_read_oss(struct snd_info_buffer *buffer);
#else
#define snd_oss_root NULL
static inline void snd_card_info_read_oss(struct snd_info_buffer *buffer) {}
#endif

__printf(2, 3)
int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...);
int snd_info_init(void);
int snd_info_done(void);

int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len);
const char *snd_info_get_str(char *dest, const char *src, int len);
struct snd_info_entry *snd_info_create_module_entry(struct module *module,
					       const char *name,
					       struct snd_info_entry *parent);
struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
					     const char *name,
					     struct snd_info_entry *parent);
void snd_info_free_entry(struct snd_info_entry *entry);
int snd_info_store_text(struct snd_info_entry *entry);
int snd_info_restore_text(struct snd_info_entry *entry);

int snd_info_card_create(struct snd_card *card);
int snd_info_card_register(struct snd_card *card);
int snd_info_card_free(struct snd_card *card);
void snd_info_card_disconnect(struct snd_card *card);
void snd_info_card_id_change(struct snd_card *card);
int snd_info_register(struct snd_info_entry *entry);

/* for card drivers */
int snd_card_proc_new(struct snd_card *card, const char *name,
		      struct snd_info_entry **entryp);

static inline void snd_info_set_text_ops(struct snd_info_entry *entry, 
	void *private_data,
	void (*read)(struct snd_info_entry *, struct snd_info_buffer *))
{
	entry->private_data = private_data;
	entry->c.text.read = read;
}

int snd_info_check_reserved_words(const char *str);

#else

#define snd_seq_root NULL
#define snd_oss_root NULL

static inline int snd_iprintf(struct snd_info_buffer *buffer, char *fmt, ...) { return 0; }
static inline int snd_info_init(void) { return 0; }
static inline int snd_info_done(void) { return 0; }

static inline int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len) { return 0; }
static inline char *snd_info_get_str(char *dest, char *src, int len) { return NULL; }
static inline struct snd_info_entry *snd_info_create_module_entry(struct module *module, const char *name, struct snd_info_entry *parent) { return NULL; }
static inline struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card, const char *name, struct snd_info_entry *parent) { return NULL; }
static inline void snd_info_free_entry(struct snd_info_entry *entry) { ; }

static inline int snd_info_card_create(struct snd_card *card) { return 0; }
static inline int snd_info_card_register(struct snd_card *card) { return 0; }
static inline int snd_info_card_free(struct snd_card *card) { return 0; }
static inline void snd_info_card_disconnect(struct snd_card *card) { }
static inline void snd_info_card_id_change(struct snd_card *card) { }
static inline int snd_info_register(struct snd_info_entry *entry) { return 0; }

static inline int snd_card_proc_new(struct snd_card *card, const char *name,
				    struct snd_info_entry **entryp) { return -EINVAL; }
static inline void snd_info_set_text_ops(struct snd_info_entry *entry __attribute__((unused)),
					 void *private_data,
					 void (*read)(struct snd_info_entry *, struct snd_info_buffer *)) {}

static inline int snd_info_check_reserved_words(const char *str) { return 1; }

#endif

/*
 * OSS info part
 */

#if defined(CONFIG_SND_OSSEMUL) && defined(CONFIG_PROC_FS)

#define SNDRV_OSS_INFO_DEV_AUDIO	0
#define SNDRV_OSS_INFO_DEV_SYNTH	1
#define SNDRV_OSS_INFO_DEV_MIDI		2
#define SNDRV_OSS_INFO_DEV_TIMERS	4
#define SNDRV_OSS_INFO_DEV_MIXERS	5

#define SNDRV_OSS_INFO_DEV_COUNT	6

int snd_oss_info_register(int dev, int num, char *string);
#define snd_oss_info_unregister(dev, num) snd_oss_info_register(dev, num, NULL)

#endif /* CONFIG_SND_OSSEMUL && CONFIG_PROC_FS */

#endif /* __SOUND_INFO_H */
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