Hi Ryusuke,
thank you for your investigations.
> On Sat, 17 Mar 2012 22:53:20 +0900 (JST), Ryusuke Konishi wrote:
>> On Sat, 17 Mar 2012 20:43:43 +0900 (JST), Ryusuke Konishi wrote:
>> > On Fri, 16 Mar 2012 07:21:39 -0700 (PDT), Sven-Göran_Bergh wrote:
>> > > Hi dexen,
>> > >
>> > > thank you for a prompt reply.
>> > >
>> > >
>> > >
>> > > >> I am in the process of migrating an embedded project
> from
>> > > >> ext2 to nilfs2 and have a problem with nilfs_cleanerd.
> It
>> > > >> does not start on mount and I cannot start it manually.
>> > > >> (...)
>> > > >
>> > > > Relevant snippet from strace of my nilfs_cleanerd (version
> nilfs-
>> > > > utils-2.0.23):
>> > > ...
>> > > > 864 statfs("/dev/shm", {f_type=0x1021994,
> f_bsize=4096,
>> > > > f_blocks=86016,
>> > > > f_bfree=86010, f_bavail=86010, f_files=754077,
> f_ffree=754075, f_fsid={0, 0},
>> > > > f_namelen=255, f_frsize=4096}
>> > > > ) = 0
>> > > > 864 futex(0x7f551010d31c, FUTEX_WAKE_PRIVATE, 2147483647)
> = 0
>> > > > 864 open("/dev/shm/sem.nilfs-cleaner-2067",
> O_RDWR|O_NOFOLLOW) = -1
>> > > > ENOENT
>> > > > (No such file or directory)
>> > > > 864 lstat("/dev/shm/sem.qLTneb", 0x7fffff54fb70)
> = -1 ENOENT (No
>> > > > such file or
>> > > > directory)
>> > > > 864 open("/dev/shm/sem.qLTneb",
> O_RDWR|O_CREAT|O_EXCL, 0700) = 6
>> > >
>> > > Hmmm, quite different.
>> >
>> > Could you confirm whether /dev/shm is mounted on /run/shm (or
>> > /var/run/shm) ?
>> >
>> > Some systems don't mount /dev/shm, and posix semaphores do not
> work in
>> > such systems.
>>
>> Oops, /dev/shm is just a directory (not a device), and /run/shm was
>> irrelevant. Sorry.
>>
>> The cause of this problem seems that posix semaphores are not
>> available in your system. I'll dig into it.
>>
>> Ryusuke Konishi
>
> I read the source code of sem_open() in glibc and found that
> sem_open() fails if there is no tmpfs (former shm fs) mount in the
> system.
>
> According to your strace log, your /dev/shm is mounted with "ramfs"
> whose magic number is 0x858458f6. This looks the cause of the error.
>
>> statfs("/dev/shm", {f_type=0x858458f6, f_bsize=4096, f_blocks=0,
>> f_bfree=0, f_bavail=0, f_files=0, f_ffree=0, f_fsid={0, 0},
>> f_namelen=255, f_frsize=4096}) = 0
>
> Try following kernel configs to enable tmpfs and mount it to
> /dev/shm instead of using ramfs.
>
> - CONFIG_SHMEM
> Generic setup ->
> Configure standard kernel features (expert users) ->
> Use full shmem filesystem
>
> - CONFIG_TMPFS
> File systems ->
> Pseudo filesystems ->
> Tmpfs virtual memory file system support (former shm fs)
You are right. I was using ramfs and when I tried with CONFIG_SHMEM
I still used ramfs, so right now I am compiling a new kernel with
both CONFIG_SHMEM and CONFIG_TMPFS. I will report my results when
I have tried the new kernel.
Thanks again
/S-G
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