[LTP] [PATCH] commands/mkswap01: Update wait_for_file function

[Stanislav Kholmanskikh]

On 03/02/2016 04:42 PM, Cyril Hrubis wrote:
> Hi!
>> Hmm, in my case swapon -L test does not fail, if there is no
>> /dev/disk/by-label/test:
>>
>> root@skholman-m7 stas]# rm /dev/disk/by-label/test
>> rm: remove symbolic link `/dev/disk/by-label/test'? y
>> [root@skholman-m7 stas]# BLKID_FILE=/tmp/none strace swapon -L test &>
>> /tmp/o; echo $?
>> 0
>> [root@skholman-m7 stas]# grep by-label /tmp/o
>> stat64("/dev/disk/by-label/test", 0x7feff9b6130) = -1 ENOENT (No such
>> file or directory)
>> [root@skholman-m7 stas]#
>>
>> (but in the strace output I see that swapon tries to read some sectors
>> from all available block devices)
>>
>> Maybe the version of libblkid plays a role here.
>>
>> Using 'blkid -t' simply makes wait_for_file/wait_for_device not fail if
>> there is no /dev/disk/by-label/ symlink. I suppose 'blkid -t' could be
>> substituted with /bin/true in my case.
>
> Unfortunately for me the swapon just looks for the symlink
> (util-linux-2.19.1) while blkid -t also reads first 512 bytes of each
> block device. So I guess that using blkid will not help in this case.
>
> Then what about just changing the 'tst_resm TWARN "The file $path
> haven't appeared"' from TWARN to TINFO?

Well, no objections then. Even if there is no symlink created in time we 
call swapon, swapon will not fail on our systems, but wait_for_file will 
still provide extra 10*10ms for the symlink to be created on your systems.

Shuang ?