Fwd: Re: df shows wrong size for smbfs/cifs/nfs/davfs mounted directories

[Toralf Förster]

Hi Bob,
"-e statfs" gave no output whereas "-e statfs64" prints some information. If 
this is waht you want, here are the results.  If you want, I can send you the 
whole output - or greped for "stat".
BTW The nfs-problem went away switching from 2.6.12-gentoo-r10 kernel to the 
new 2.6.13 kernel-gentoo-r3. Now I get a "time out"

Ok, here are the results:

DAV:
----------------------------------------------------------------
n22 # df -m /mnt/ramdisk/dav/ /mnt/dav_n22/
Filesystem           1M-blocks      Used Available Use% Mounted on
tmpfs                      660         1       660   1% /mnt/ramdisk
http://n22/address@hidden/
                          8790         0      8790   0% /mnt/dav_n22
n22 # strace -e statfs64 df -m /mnt/ramdisk/dav/ /mnt/dav_n22/
statfs64("/mnt/ramdisk", 84, {f_type=0x1021994, f_bsize=4096, f_blocks=168960, 
f_bfree=168956, f_bavail=168956, f_files=129449, f_ffree=129441, f_fsid={0, 
0}, f_namelen=255, f_frsize=4096}) = 0
statfs64("/mnt/dav_n22", 84, {f_type="CODA_SUPER_MAGIC", f_bsize=1024, 
f_blocks=9000000, f_bfree=9000000, f_bavail=9000000, f_files=9000000, 
f_ffree=9000000, f_fsid={0, 0}, f_namelen=255, f_frsize=1024}) = 0


NFS-server n22_tun is up and running:
----------------------------------------------------------------
n22_uml ~ # df /mnt/nfs/n22_tmp
Filesystem           1K-blocks      Used Available Use% Mounted on
n22_tun:/tmp          14011712  10641536   2658400  81% /mnt/nfs/n22_tmp
n22_uml ~ # strace -e statfs64 df /mnt/nfs/n22_tmp
Filesystem           1K-blocks      Used Available Use% Mounted on
statfs64("/mnt/nfs/n22_tmp", 84, {f_type="NFS_SUPER_MAGIC", f_bsize=32768, 
f_blocks=437866, f_bfree=105318, f_bavail=83075, f_files=1782368, 
f_ffree=1254493, f_fsid={0, 0}, f_namelen=255, f_frsize=32768}) = 0
n22_tun:/tmp          14011712  10641536   2658400  81% /mnt/nfs/n22_tmp


NFS-server n22_tun was stopped:
----------------------------------------------------------------
n22_uml ~ # df /mnt/nfs/n22_tmp
Filesystem           1K-blocks      Used Available Use% Mounted on
n22_tun:/tmp         77371252437321868667518976         0 
77371252437321868667518976   0% /mnt/nfs/n22_tmp
n22_uml ~ # strace -e statfs64 df /mnt/nfs/n22_tmp
Filesystem           1K-blocks      Used Available Use% Mounted on
statfs64("/mnt/nfs/n22_tmp", 84, {f_type="NFS_SUPER_MAGIC", 
f_bsize=4294967295, f_blocks=4294967295, f_bfree=4294967295, 
f_bavail=4294967295, f_files=0, f_ffree=0, f_fsid={0, 0}, f_namelen=0, 
f_frsize=4294967295}) = 0
n22_tun:/tmp         77371252437321868667518976         0 
77371252437321868667518976   0% /mnt/nfs/n22_tmp


----------  Weitergeleitete Nachricht  ----------

Subject: Re: df shows wrong size for smbfs/cifs/nfs/davfs mounted directories
Date: Samstag 08 Oktober 2005 19:52
From: Bob Proulx <address@hidden>
To: Toralf Förster <address@hidden>
Cc: address@hidden

Toralf Förster wrote:
> I am wondering about the displayed free disk space:
> n22 ~ # df -m /mnt/ramdisk/dav/ /mnt/dav/
> Filesystem           1M-blocks      Used Available Use% Mounted on
> tmpfs                      660         1       660   1% /mnt/ramdisk
> http://n22/davfs/         8790         0      8790   0% /mnt/dav
>
> Why there seems to be ~8,8 GB space free whereas the whole ramdisk has only
> 660 MB ?

Thanks for the report.  Please run the experiment again using strace
to find the result of the statfs(2) calls made by the program to the
kernel.

  strace -e statfs df -m /mnt/ramdisk/dav/ /mnt/dav/

This will report what information the df command is getting and
therefore will explain why df is printing what it is printing.

> normal behaviour (n22_uml is the UML sytem, n22_tun the host) :
> n22_uml ~ # df /mnt/nfs/n22_tmp
> Filesystem           1K-blocks      Used Available Use% Mounted on
> n22_tun:/tmp          14011712  10646784   2653184  81% /mnt/nfs/n22_tmp
>
> Now I stop nfs at n22_tun:
> n22 ~ # /etc/init.d/nfs stop
> ...
> Ang got finally under UML:
> n22_uml ~ # df /mnt/nfs/n22_tmp
> Filesystem           1K-blocks      Used Available Use% Mounted on
> n22_tun:/tmp         77371252437321868667518976         0
> 77371252437321868667518976   0% /mnt/nfs/n22_tmp

Please do the same thing here too.

  strace -e statfs df /mnt/nfs/n22_tmp

> Here the exports - file from the host:
> n22 ~ # cat /etc/exports
> # /etc/exports: NFS file systems being exported.  See exports(5).
> /tmp            n22_uml(rw,sync,all_squash)

Looks fine to me.

> and the appropriate fstab - entry under UML:
> n22_uml ~ # grep n22_tmp /etc/fstab
> n22_tun:/tmp            /mnt/nfs/n22_tmp        nfs     soft 0 0

I recommend to avoid the soft option for nfs mounts.  It can lead to
silent data corruption.  But I don't think it is related to your
current problem.

Bob

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MfG/Regards
Toralf