[gentoo-user] dir is rwx but can't create file

[gentoo-user] dir is rwx but can't create file

[Andrey Vul]

Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
/tmp/foo => strerror(ENOENT)).
However, this is done as root and the dirs are marked 755 root:root.
df -i shows only 2% inode usage.
Any explanation as to why a rwx-ed dir can't be written to? This is
breaking quite a few of the init scripts.

--
Andrey Vul
begin-base64 600 sig
bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3Jv
bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
`
end

Re: [gentoo-user] dir is rwx but can't create file

[Alan McKinnon]

On Wednesday 28 July 2010 22:20:17 Andrey Vul wrote:
> Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
> /tmp/foo => strerror(ENOENT)).
> However, this is done as root and the dirs are marked 755 root:root.
> df -i shows only 2% inode usage.
> Any explanation as to why a rwx-ed dir can't be written to? This is
> breaking quite a few of the init scripts.
> 
> --
> Andrey Vul
> begin-base64 600 sig
> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3J
> v bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
> `
> end

sounds like / is mounted read-only


-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] dir is rwx but can't create file

[Bill Longman]

On 07/28/2010 01:52 PM, Alan McKinnon wrote:
> On Wednesday 28 July 2010 22:20:17 Andrey Vul wrote:
>> Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
>> /tmp/foo => strerror(ENOENT)).
>> However, this is done as root and the dirs are marked 755 root:root.
>> df -i shows only 2% inode usage.
>> Any explanation as to why a rwx-ed dir can't be written to? This is
>> breaking quite a few of the init scripts.
>>
>> --
>> Andrey Vul
>> begin-base64 600 sig
>> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3J
>> v bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
>> `
>> end
> 
> sounds like / is mounted read-only

Do read-only filesystems typically reply ENOENT when trying to create a
file? It's usually something like "read-only filesystem" in that case.
ENOENT means it can't even find the file.

[gentoo-user] Re: dir is rwx but can't create file

[Andrey Vul]

If / was mounted ro, touch would output strerror(EROFS), not strerror(ENOENT)

On 2010-07-28, Bill Longman <bill.longman@gmail.com> wrote:
> On 07/28/2010 01:52 PM, Alan McKinnon wrote:
>> On Wednesday 28 July 2010 22:20:17 Andrey Vul wrote:
>>> Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
>>> /tmp/foo => strerror(ENOENT)).
>>> However, this is done as root and the dirs are marked 755 root:root.
>>> df -i shows only 2% inode usage.
>>> Any explanation as to why a rwx-ed dir can't be written to? This is
>>> breaking quite a few of the init scripts.
>>>
>>> --
>>> Andrey Vul
>>> begin-base64 600 sig
>>> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3J
>>> v bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
>>> `
>>> end
>>
>> sounds like / is mounted read-only
>
> Do read-only filesystems typically reply ENOENT when trying to create a
> file? It's usually something like "read-only filesystem" in that case.
> ENOENT means it can't even find the file.
>
>

-- 
Sent from my mobile device

Andrey Vul
begin-base64 600 sig
bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3Jv
bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
`
end

[gentoo-user] Re: dir is rwx but can't create file

[Andrey Vul]

Also, echo > /tmp/foo => same thing
It looks like a problem with open(..., O_CREAT|O_TRUNC, 644), but i'll
retry strace'ing the open,write and see where the problem chain starts

On 2010-07-29, Andrey Vul <andrey.vul@gmail.com> wrote:
> If / was mounted ro, touch would output strerror(EROFS), not
> strerror(ENOENT)
>
> On 2010-07-28, Bill Longman <bill.longman@gmail.com> wrote:
>> On 07/28/2010 01:52 PM, Alan McKinnon wrote:
>>> On Wednesday 28 July 2010 22:20:17 Andrey Vul wrote:
>>>> Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
>>>> /tmp/foo => strerror(ENOENT)).
>>>> However, this is done as root and the dirs are marked 755 root:root.
>>>> df -i shows only 2% inode usage.
>>>> Any explanation as to why a rwx-ed dir can't be written to? This is
>>>> breaking quite a few of the init scripts.
>>>>
>>>> --
>>>> Andrey Vul
>>>> begin-base64 600 sig
>>>> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3J
>>>> v bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
>>>> `
>>>> end
>>>
>>> sounds like / is mounted read-only
>>
>> Do read-only filesystems typically reply ENOENT when trying to create a
>> file? It's usually something like "read-only filesystem" in that case.
>> ENOENT means it can't even find the file.
>>
>>
>
> --
> Sent from my mobile device
>
> Andrey Vul
> begin-base64 600 sig
> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3Jv
> bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
> `
> end
>

-- 
Sent from my mobile device

Andrey Vul
begin-base64 600 sig
bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3Jv
bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
`
end

[gentoo-user] Re: dir is rwx but can't create file

[Andrey Vul]

While /tmp's mode is 1777, it doesnt make a difference since the same
error occurs with /etc, /lib32, and /var.

On 2010-07-29, Andrey Vul <andrey.vul@gmail.com> wrote:
> Also, echo > /tmp/foo => same thing
> It looks like a problem with open(..., O_CREAT|O_TRUNC, 644), but i'll
> retry strace'ing the open,write and see where the problem chain starts
>
> On 2010-07-29, Andrey Vul <andrey.vul@gmail.com> wrote:
>> If / was mounted ro, touch would output strerror(EROFS), not
>> strerror(ENOENT)
>>
>> On 2010-07-28, Bill Longman <bill.longman@gmail.com> wrote:
>>> On 07/28/2010 01:52 PM, Alan McKinnon wrote:
>>>> On Wednesday 28 July 2010 22:20:17 Andrey Vul wrote:
>>>>> Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
>>>>> /tmp/foo => strerror(ENOENT)).
>>>>> However, this is done as root and the dirs are marked 755 root:root.
>>>>> df -i shows only 2% inode usage.
>>>>> Any explanation as to why a rwx-ed dir can't be written to? This is
>>>>> breaking quite a few of the init scripts.
>>>>>
>>>>> --
>>>>> Andrey Vul
>>>>> begin-base64 600 sig
>>>>> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3J
>>>>> v bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
>>>>> `
>>>>> end
>>>>
>>>> sounds like / is mounted read-only
>>>
>>> Do read-only filesystems typically reply ENOENT when trying to create a
>>> file? It's usually something like "read-only filesystem" in that case.
>>> ENOENT means it can't even find the file.
>>>
>>>
>>
>> --
>> Sent from my mobile device
>>
>> Andrey Vul
>> begin-base64 600 sig
>> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3Jv
>> bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
>> `
>> end
>>
>
> --
> Sent from my mobile device
>
> Andrey Vul
> begin-base64 600 sig
> bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3Jv
> bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
> `
> end
>

-- 
Sent from my mobile device

Andrey Vul
begin-base64 600 sig
bXNuLCBob21lOiBhbmRyZXkudnVsQGdtYWlsLmNvbQ0KdSBvZiB0OiBhbmRyZXkudnVsQHV0b3Jv
bnRvLmNhDQpzbXMsIHZvaWNlbWFpbDogNDE2MzAzOTkyMw0K
`
end

[gentoo-user] Re: dir is rwx but can't create file

[walt]

On 07/28/2010 01:20 PM, Andrey Vul wrote:
> Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
> /tmp/foo =>  strerror(ENOENT)).
> However, this is done as root and the dirs are marked 755 root:root.

Is the sticky bit set on /tmp?

drwxrwxrwt  26 root root 36864 2010-07-29 04:15 tmp/
          ^

Re: [gentoo-user] Re: dir is rwx but can't create file

[Alan McKinnon]

On Thursday 29 July 2010 13:24:29 walt wrote:
> On 07/28/2010 01:20 PM, Andrey Vul wrote:
> > Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
> > /tmp/foo =>  strerror(ENOENT)).
> > However, this is done as root and the dirs are marked 755 root:root.
> 
> Is the sticky bit set on /tmp?
> 
> drwxrwxrwt  26 root root 36864 2010-07-29 04:15 tmp/
>           ^


That will not make a difference.
Sticky bit on a directory does not affect creation of files, only WHO may 
delete them (regardless of w permissions on /tmp)



-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Re: dir is rwx but can't create file

[Alex Schuster]

walt writes:

> On 07/28/2010 01:20 PM, Andrey Vul wrote:
> > Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
> > /tmp/foo =>  strerror(ENOENT)).
> > However, this is done as root and the dirs are marked 755 root:root.

Are all these directories located on the root file system?

> Is the sticky bit set on /tmp?
> 
> drwxrwxrwt  26 root root 36864 2010-07-29 04:15 tmp/
>           ^

Well, it set or not, this would not prevent the creation of files.

I have no idea what's going on here. I'd force a fsck (touch /forcefsck; 
reboot) to make sure it's no file system problem. And what about a live-
cd, does the problem happen then, too?

	Wonko

Re: [gentoo-user] Re: dir is rwx but can't create file

[Andrey Vul]

On Thu, Jul 29, 2010 at 08:31, Alex Schuster <wonko@wonkology.org> wrote:
> walt writes:
>
>> On 07/28/2010 01:20 PM, Andrey Vul wrote:
>> > Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
>> > /tmp/foo =>  strerror(ENOENT)).
>> > However, this is done as root and the dirs are marked 755 root:root.
>
> Are all these directories located on the root file system?
>
>> Is the sticky bit set on /tmp?
>>
>> drwxrwxrwt  26 root root 36864 2010-07-29 04:15 tmp/
>>           ^
>
> Well, it set or not, this would not prevent the creation of files.
>
> I have no idea what's going on here. I'd force a fsck (touch /forcefsck;
> reboot) to make sure it's no file system problem. And what about a live-
> cd, does the problem happen then, too?
>

fsck -f followed by use of USB-SATA bridge seems to work. However, my
laptop just died, so I can't really test it on the laptop.

Re: [gentoo-user] Re: dir is rwx but can't create file

[Andrey Vul]

On Fri, Jul 30, 2010 at 01:34, Andrey Vul <andrey.vul@gmail.com> wrote:
> On Thu, Jul 29, 2010 at 08:31, Alex Schuster <wonko@wonkology.org> wrote:
>> walt writes:
>>
>>> On 07/28/2010 01:20 PM, Andrey Vul wrote:
>>> > Creating files in /tmp, /etc, /lib32, and /var return ENOENT (touch
>>> > /tmp/foo =>  strerror(ENOENT)).
>>> > However, this is done as root and the dirs are marked 755 root:root.
>>
>> Are all these directories located on the root file system?
>>
>>> Is the sticky bit set on /tmp?
>>>
>>> drwxrwxrwt  26 root root 36864 2010-07-29 04:15 tmp/
>>>           ^
>>
>> Well, it set or not, this would not prevent the creation of files.
>>
>> I have no idea what's going on here. I'd force a fsck (touch /forcefsck;
>> reboot) to make sure it's no file system problem. And what about a live-
>> cd, does the problem happen then, too?
>>
>
> fsck -f followed by use of USB-SATA bridge seems to work. However, my
> laptop just died, so I can't really test it on the laptop.
>

Quoting fsck.jfs : "Incorrect link counts have been detected. Will correct."
Apparently, some subtle data corruption was invisible by fsck -p but
noticed by fsck -f.
A corrupt inode does explain why the directory was somehow 555 in behavior.