[CRIU] [PATCH v4 2/6] files-reg: Make try_clean_ghost() use struct ghost_file ptr

[Kirill Tkhai]

On 06.02.2016 04:03, Andrew Vagin wrote:
> Kirill, here is one more issue for you. It was introduced in this patch.
>
> [root at fc22-vm criu]# ./test/zdtm.py run -t zdtm/live/static/unlink_fstat00 --fault 2 --report report -f h 
> === Run 1/1 ================
> 
> =================== Run zdtm/live/static/unlink_fstat00 in h ===================
> Start test
> ./unlink_fstat00 --pidfile=unlink_fstat00.pid --outfile=unlink_fstat00.out --filename=unlink_fstat00.test
> Dangling ghost file
> Run criu dump
> Forcing 2 fault
> Running zdtm/live/static/unlink_fstat00.hook(--pre-restore)
> Run criu restore
> Forcing 2 fault
> =[log]=> dump/zdtm/live/static/unlink_fstat00/72/1/restore.log
> ------------------------ grep Error ------------------------
> (00.014193)     72: Error (cr-restore.c:1606): BUG at cr-restore.c:1606
> (00.021403) Error (cr-restore.c:1305): 72 killed by signal 11
> (00.021431) Error (cr-restore.c:2127): Restoring FAILED.
> ------------------------ ERROR OVER ------------------------
> Running zdtm/live/static/unlink_fstat00.hook(--fault, restore)
> ###### Test zdtm/live/static/unlink_fstat00 FAIL at hook --fault restore #######
> 
> ##################################### FAIL #####################################

ghost_files are changed in other process, and the changes are not visible to parent..

This patch is to be able to create ghost files under names with a digit suffix,
if the standard  "%s.cr.%x.ghost" (rfi->path, rfe->remap_id)  is not available.
So, it's need a different solution.

We can't check disk state from parent, because mount points are restored only in
restore_task_with_children() from child. So, the child should report parent,
which ghosts names it has changed.

shmem is not infinity; sending the information about changing of names using
socket is ugly. Do you know better solution?
 
> On Mon, Jan 25, 2016 at 07:39:44PM +0300, Kirill Tkhai wrote:
>> This cleanup will be used in next patch.
>>
>> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
>> ---
>>  files-reg.c |   15 +++++++--------
>>  1 file changed, 7 insertions(+), 8 deletions(-)
>>
>> diff --git a/files-reg.c b/files-reg.c
>> index 735a15a..648c8d2 100644
>> --- a/files-reg.c
>> +++ b/files-reg.c
>> @@ -432,17 +432,18 @@ int prepare_remaps(void)
>>  	return ret;
>>  }
>>  
>> -static void try_clean_ghost(struct remap_info *ri)
>> +static void try_clean_ghost(struct ghost_file *gf)
>>  {
>>  	char path[PATH_MAX];
>>  	int mnt_id, ret;
>>  
>> -	mnt_id = ri->rfi->rfe->mnt_id; /* rirfirfe %) */
>> +	mnt_id = gf->remap.rmnt_id;
>>  	ret = rst_get_mnt_root(mnt_id, path, sizeof(path));
>>  	if (ret < 0)
>>  		return;
>>  
>> -	ghost_path(path + ret, sizeof(path) - 1, ri->rfi, ri->rfe);
>> +	snprintf(path + ret, PATH_MAX - ret, "/%s", gf->remap.rpath);
>> +
>>  	if (!unlink(path)) {
>>  		pr_info(" `- X [%s] ghost\n", path);
>>  		return;
>> @@ -455,7 +456,6 @@ static void try_clean_ghost(struct remap_info *ri)
>>  	 */
>>  
>>  	if ((errno == EISDIR)) {
>> -		strncpy(path + ret, ri->rfi->path, sizeof(path) - 1);
>>  		if (!rmdir(path)) {
>>  			pr_info(" `- Xd [%s] ghost\n", path);
>>  			return;
>> @@ -467,7 +467,7 @@ static void try_clean_ghost(struct remap_info *ri)
>>  
>>  void try_clean_remaps(int ns_fd)
>>  {
>> -	struct remap_info *ri;
>> +	struct ghost_file *gf;
>>  	int old_ns = -1;
>>  	int cwd_fd = -1;
>>  
>> @@ -497,9 +497,8 @@ void try_clean_remaps(int ns_fd)
>>  		}
>>  	}
>>  
>> -	list_for_each_entry(ri, &remaps, list)
>> -		if (ri->rfe->remap_type == REMAP_TYPE__GHOST)
>> -			try_clean_ghost(ri);
>> +	list_for_each_entry(gf, &ghost_files, list)
>> +		try_clean_ghost(gf);
>>  
>>  	if (old_ns >= 0) {
>>  		if (setns(old_ns, CLONE_NEWNS) < 0)
>>