[CRIU] [PATCH 2/4] mount: add support for external block devices

[Pavel Emelyanov]

On 04/19/2016 03:44 AM, Andrew Vagin wrote:
> On Mon, Apr 18, 2016 at 07:36:52PM +0300, Pavel Emelyanov wrote:
>> On 04/15/2016 01:19 AM, Andrey Vagin wrote:
>>> From: Andrew Vagin <avagin at virtuozzo.com>
>>>
>>> It works like enable-fs, in this case we allow to mount a specified block device.
>>>
>>> Options:
>>> dump:		--external mnt[MAJOR:MINOR]
>>> restore:	--mnt-ext-map mnt[MAJOR:MINOR]:DEVPATH
>>
>> We don't have --mnt-ext-map option :\
> 
> I mean --ext-mount-map
>>
>> Please, explain what the option arguments mean.

Please, explain what the option arguments mean.

>>> https://jira.sw.ru/browse/PSBM-39381
>>>
>>> Signed-off-by: Andrew Vagin <avagin at virtuozzo.com>
>>> ---
>>>  criu/crtools.c    |  1 +
>>>  criu/mount.c      | 11 +++++++++++
>>>  criu/proc_parse.c | 10 ++++++++++
>>>  3 files changed, 22 insertions(+)
>>>
>>> diff --git a/criu/crtools.c b/criu/crtools.c
>>> index 02a24e7..3598b1b 100644
>>> --- a/criu/crtools.c
>>> +++ b/criu/crtools.c
>>> @@ -882,6 +882,7 @@ usage:
>>>  "                        Formats of RES:\n"
>>>  "                            tty[rdev:dev]\n"
>>>  "                            file[mnt_id:inode]\n"
>>> +"                            mnt[MAJOR/MINOR]\n"
>>>  "  --inherit-fd fd[<num>]:<existing>\n"
>>>  "                        Inherit file descriptors. This allows to treat file descriptor\n"
>>>  "                        <num> as being already opened via <existing> one and instead of\n"
>>> diff --git a/criu/mount.c b/criu/mount.c
>>> index f57b10c..85eeeda 100644
>>> --- a/criu/mount.c
>>> +++ b/criu/mount.c
>>> @@ -1818,6 +1818,8 @@ static struct fstype *__find_fstype_by_name(char *fst, bool force_auto)
>>>  {
>>>  	int i;
>>>  
>>> +	if (fst == (void *) FSTYPE__AUTO)
>>> +		return &fstypes[1];
>>>  	/*
>>>  	 * This fn is required for two things.
>>>  	 * 1st -- to check supported filesystems (as just mounting
>>> @@ -2091,6 +2093,15 @@ static char *resolve_source(struct mount_info *mi)
>>>  
>>>  	if (mi->fstype->code == FSTYPE__AUTO) {
>>>  		struct stat st;
>>> +		char devstr[64];
>>> +		struct ext_mount *key;
>>> +
>>> +		snprintf(devstr, sizeof(devstr), "mnt[%d/%d]",
>>> +				kdev_major(mi->s_dev), kdev_minor(mi->s_dev));
>>> +
>>> +		key = ext_mount_lookup(devstr);
>>> +		if (key)
>>> +			return key->val;
>>>  
>>>  		if (!stat(mi->source, &st) && S_ISBLK(st.st_mode) &&
>>>  		    major(st.st_rdev) == kdev_major(mi->s_dev) &&
>>> diff --git a/criu/proc_parse.c b/criu/proc_parse.c
>>> index 2dd8dc4..55f0f5e 100644
>>> --- a/criu/proc_parse.c
>>> +++ b/criu/proc_parse.c
>>> @@ -1292,6 +1292,16 @@ static int parse_mountinfo_ent(char *str, struct mount_info *new, char **fsname)
>>>  
>>>  	new->fstype = find_fstype_by_name(*fsname);
>>>  
>>> +	if (new->fstype->code == FSTYPE__UNSUPPORTED) {
>>> +		char devstr[64];
>>> +
>>> +		snprintf(devstr, sizeof(devstr), "mnt[%d/%d]",
>>> +				kdev_major(new->s_dev),  kdev_minor(new->s_dev));
>>> +
>>> +		if (external_lookup_id(devstr))
>>> +			new->fstype = find_fstype_by_name((void *)FSTYPE__AUTO);
>>> +	}
>>> +
>>>  	new->options = xmalloc(strlen(opt) + 1);
>>>  	if (!new->options)
>>>  		goto err;
>>>
>>
> .
>