statvfs() return large f_bavail on a 10TB drive

statvfs() return large f_bavail on a 10TB drive

[Kirubakaran Kaliannan]

Hi All,

I have couple of  xfs filesystem  on a 10TB STAT drive.

After 50% of filesystem is full, the df –kH is returning a large f_bavail.


Filesystem                   Size  Used Avail Use% Mounted on
/dev/dm-4                     10T  -12T   22T    - /mnt/a
/dev/dm-3                     10T  -12T   22T    - /mnt/b

I tried statvfs() and got the same large f_bavail as well,

        total filesystem size = 9763506176 KB
        total Available size = 21279656740 KB
        total used size = -11516150564 KB

We are using Ubuntu 3.18.19 Linux kernel/xfs.

If I unmount and mount the filesysem back, the f_bavail values are back to
normal.

Can you please point me, if this is something a known issue got fixed in
XFS in the later version, or any lead may help.
It is difficult at this point of time to upgrade the XFS for this specific
issue.

Thanks,
-kiru

Re: statvfs() return large f_bavail on a 10TB drive

[Darrick J. Wong]

On Fri, Apr 13, 2018 at 12:10:19PM +0530, Kirubakaran Kaliannan wrote:
> Hi All,
> 
> I have couple of  xfs filesystem  on a 10TB STAT drive.
> 
> After 50% of filesystem is full, the df –kH is returning a large f_bavail.
> 
> 
> Filesystem                   Size  Used Avail Use% Mounted on
> /dev/dm-4                     10T  -12T   22T    - /mnt/a
> /dev/dm-3                     10T  -12T   22T    - /mnt/b
> 
> I tried statvfs() and got the same large f_bavail as well,
> 
>         total filesystem size = 9763506176 KB
>         total Available size = 21279656740 KB

21279656740KB = 0x100000000000 | (about 50% of the space) ?

Bitflip?

--D

>         total used size = -11516150564 KB
> 
> We are using Ubuntu 3.18.19 Linux kernel/xfs.
> 
> If I unmount and mount the filesysem back, the f_bavail values are back to
> normal.
> 
> Can you please point me, if this is something a known issue got fixed in
> XFS in the later version, or any lead may help.
> It is difficult at this point of time to upgrade the XFS for this specific
> issue.
> 
> Thanks,
> -kiru
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

RE: statvfs() return large f_bavail on a 10TB drive

[Kirubakaran Kaliannan]

Hi Darrick,

Yes this looks like the bitflip !
Do you have seen any occurrence of this before or maybe something related to
a in-memory corruption ?

Thaks
-kiru

-----Original Message-----
From: Darrick J. Wong [mailto:darrick.wong@oracle.com]
Sent: Friday, April 13, 2018 9:13 PM
To: Kirubakaran Kaliannan
Cc: linux-xfs@vger.kernel.org
Subject: Re: statvfs() return large f_bavail on a 10TB drive

On Fri, Apr 13, 2018 at 12:10:19PM +0530, Kirubakaran Kaliannan wrote:
> Hi All,
>
> I have couple of  xfs filesystem  on a 10TB STAT drive.
>
> After 50% of filesystem is full, the df –kH is returning a large f_bavail.
>
>
> Filesystem                   Size  Used Avail Use% Mounted on
> /dev/dm-4                     10T  -12T   22T    - /mnt/a
> /dev/dm-3                     10T  -12T   22T    - /mnt/b
>
> I tried statvfs() and got the same large f_bavail as well,
>
>         total filesystem size = 9763506176 KB
>         total Available size = 21279656740 KB

21279656740KB = 0x100000000000 | (about 50% of the space) ?

Bitflip?

--D

>         total used size = -11516150564 KB
>
> We are using Ubuntu 3.18.19 Linux kernel/xfs.
>
> If I unmount and mount the filesysem back, the f_bavail values are back to
> normal.
>
> Can you please point me, if this is something a known issue got fixed in
> XFS in the later version, or any lead may help.
> It is difficult at this point of time to upgrade the XFS for this specific
> issue.
>
> Thanks,
> -kiru
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: statvfs() return large f_bavail on a 10TB drive

[Darrick J. Wong]

On Mon, Apr 23, 2018 at 09:56:58AM +0530, Kirubakaran Kaliannan wrote:
> Hi Darrick,
> 
> Yes this looks like the bitflip !
> Do you have seen any occurrence of this before or maybe something related to
> a in-memory corruption ?

Usually only on machines with bad memory or use-after-free bugs in the
kernel.

--D

> Thaks
> -kiru
> 
> -----Original Message-----
> From: Darrick J. Wong [mailto:darrick.wong@oracle.com]
> Sent: Friday, April 13, 2018 9:13 PM
> To: Kirubakaran Kaliannan
> Cc: linux-xfs@vger.kernel.org
> Subject: Re: statvfs() return large f_bavail on a 10TB drive
> 
> On Fri, Apr 13, 2018 at 12:10:19PM +0530, Kirubakaran Kaliannan wrote:
> > Hi All,
> >
> > I have couple of  xfs filesystem  on a 10TB STAT drive.
> >
> > After 50% of filesystem is full, the df –kH is returning a large f_bavail.
> >
> >
> > Filesystem                   Size  Used Avail Use% Mounted on
> > /dev/dm-4                     10T  -12T   22T    - /mnt/a
> > /dev/dm-3                     10T  -12T   22T    - /mnt/b
> >
> > I tried statvfs() and got the same large f_bavail as well,
> >
> >         total filesystem size = 9763506176 KB
> >         total Available size = 21279656740 KB
> 
> 21279656740KB = 0x100000000000 | (about 50% of the space) ?
> 
> Bitflip?
> 
> --D
> 
> >         total used size = -11516150564 KB
> >
> > We are using Ubuntu 3.18.19 Linux kernel/xfs.
> >
> > If I unmount and mount the filesysem back, the f_bavail values are back to
> > normal.
> >
> > Can you please point me, if this is something a known issue got fixed in
> > XFS in the later version, or any lead may help.
> > It is difficult at this point of time to upgrade the XFS for this specific
> > issue.
> >
> > Thanks,
> > -kiru
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html