[CRIU] [PATCH v4 04/17] protobuf: autofs mount entry introduced

[Stanislav Kinsburskiy]

19.01.2016 14:37, Pavel Emelyanov пишет:
> On 01/07/2016 07:09 PM, Stanislav Kinsburskiy wrote:
>> This entry will be used to carry all the autofs parameters, required to
>> restore mount point.
>>
>> Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
>> ---
>>   include/mount.h    |    3 +++
>>   mount.c            |   14 ++++++++++++++
>>   protobuf/mnt.proto |   16 ++++++++++++++++
>>   3 files changed, 33 insertions(+)
>>
>> diff --git a/include/mount.h b/include/mount.h
>> index b3bbdce..d2ccd64 100644
>> --- a/include/mount.h
>> +++ b/include/mount.h
>> @@ -5,6 +5,7 @@
>>   
>>   #include "asm/types.h"
>>   #include "list.h"
>> +#include "protobuf/mnt.pb-c.h"
>>   
>>   struct proc_mountinfo;
>>   struct pstree_item;
>> @@ -84,6 +85,8 @@ struct mount_info {
>>   	struct list_head	postpone;
>>   
>>   	void			*private;	/* associated filesystem data */
>> +
>> +	AutofsEntry		*autofs;
> Why not use the void *private field?

Makes sense.

>>   };
>>   
>>   extern struct mount_info *mntinfo;
>> diff --git a/mount.c b/mount.c
>> index f7df464..645c4b4 100644
>> --- a/mount.c
>> +++ b/mount.c
>> @@ -1873,6 +1873,8 @@ static int dump_one_mountpoint(struct mount_info *pm, struct cr_img *img)
>>   	} else
>>   		me.root = pm->root;
>>   
>> +	me.autofs = pm->autofs;
>> +
>>   	if (pb_write_one(img, &me, PB_MNT))
>>   		return -1;
>>   
>> @@ -2759,6 +2761,15 @@ static int get_mp_mountpoint(MntEntry *me, struct mount_info *mi, char *root, in
>>   	return 0;
>>   }
>>   
>> +static int get_mp_autofs(MntEntry *me, struct mount_info *mi)
>> +{
>> +	mi->autofs = xmalloc(sizeof(*mi->autofs));
>> +	if (!mi->autofs)
>> +		return -1;
>> +	mi->autofs = me->autofs;
> Leans xmalloc-ed mem above.

Thanks.

>> +	return 0;
>> +}
>> +
>>   static int collect_mnt_from_image(struct mount_info **pms, struct ns_id *nsid)
>>   {
>>   	MntEntry *me = NULL;
>> @@ -2835,6 +2846,9 @@ static int collect_mnt_from_image(struct mount_info **pms, struct ns_id *nsid)
>>   		if (get_mp_mountpoint(me, pm, root, root_len))
>>   			goto err;
>>   
>> +		if (get_mp_autofs(me, pm))
>> +			goto err;
>> +
>>   		pr_debug("\tRead %d mp @ %s\n", pm->mnt_id, pm->mountpoint);
>>   	}
>>   
>> diff --git a/protobuf/mnt.proto b/protobuf/mnt.proto
>> index fe1e4bb..2b697c6 100644
>> --- a/protobuf/mnt.proto
>> +++ b/protobuf/mnt.proto
>> @@ -22,6 +22,20 @@ enum fstype {
>>   	AUTOFS			= 18;
>>   };
>>   
>> +message autofs_entry {
>> +	required int32		fd			= 1;
>> +	required int32		pgrp			= 2;
>> +	required int32		timeout			= 3;
>> +	required int32		minproto		= 4;
>> +	required int32		maxproto		= 5;
>> +	required int32		mode			= 6;
>> +
>> +	optional int32		uid			= 7;
>> +	optional int32		gid			= 8;
>> +
>> +	optional int32		read_fd			= 9;
> Why two fd entries here? On just fd and the other one is read_fd.

One ("fd") represents write pipe file descriptor from mount options.
Another ("read_fd") represents read pipe file descriptor, which is 
required only if the former one was closed on dump.

>> +}
>> +
>>   message mnt_entry {
>>   	required uint32		fstype			= 1;
>>   	required uint32		mnt_id			= 2;
>> @@ -45,4 +59,6 @@ message mnt_entry {
>>   
>>   	optional bool		deleted			= 16;
>>   	optional uint32		sb_flags		= 17 [(criu).hex = true];
>> +
>> +	optional autofs_entry	autofs			= 18;
> Plz, describe how this field will be managed for mountpoints
> sharing the same superblock (e.g. mount and bind-mount of it)?

All of them will have the same data here. I.e. it's duplicated.

>>   }
>>
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>>