[linux-cifs-client] dataloss with cifs and 2.6.15

[studdugie]

On 1/5/06, Hujer <hujer at users.sf.net> wrote:
> Hi,
>
> i have just found a bug in cifs
> from the mailing list archive it seems you are already working on this but this i will just repeat it here to
> make sure
>
> i used 2.6.15 kernel from debian unstable on both boxes and cifs is 1.39 (i guess the one from vanilla 2.6.15)
>
> i created share with samba (latest samba in debian unstable)
> and mounted it using cifs with directio option
> when i do
> echo "blabla" >file
> echo "t" >>file
> the result is
>
> cat file
> t
> abla
>
> it seems that using >> doesnt seek to the end,
> same happens if you make small app that uses fopen with "a+"
>
> without directio it seems to work properly with result
> blabla
> t
>
>
> i found other problem with permissions, do this as root on cifs mount:
> G2:/mnt/tsa# touch file
> G2:/mnt/tsa# chmod a-rwx file
> G2:/mnt/tsa# echo "test" >>file
> -bash: file: Permission denied
>
> if you do the same on non-cifs fs it works
> G2:/mnt/tsa# cd ..
> G2:/mnt# touch file
> G2:/mnt# chmod a-rwx file
> G2:/mnt# echo "test" >>file
> G2:/mnt# cat file
> test
> (yes it may be crazy to do it, but still it should work)
>
>
> sysinfo:
> Linux MONSTER 2.6.15-1-k7 #1 Tue Jan 3 10:46:46 UTC 2006 i686 GNU/Linux
>
> MONSTER:~# modinfo cifs
> filename:       /lib/modules/2.6.15-1-k7/kernel/fs/cifs/cifs.ko
> author:         Steve French <sfrench at us.ibm.com>
> license:        GPL
> description:    VFS to access servers complying with the SNIA CIFS Specification e.g. Samba and Windows
> version:        1.39
> vermagic:       2.6.15-1-k7 K7 gcc-4.0
> depends:
> srcversion:     BAA2B662E133E679F5A6DF9
> parm:           cifs_max_pending:Simultaneous requests to server. Default: 50 Range: 2 to 256 (int)
> parm:           cifs_min_small:Small network buffers in pool. Default: 30 Range: 2 to 256 (int)
> parm:           cifs_min_rcv:Network buffers in pool. Default: 4 Range: 1 to 64 (int)
> parm:           CIFSMaxBufSize:Network buffer size (not including header). Default: 16384 Range: 8192 to 130048 (int)
>
>
> thanks
> Hujer
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> linux-cifs-client at lists.samba.org
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>
I've just confirmed that this bug also affects the cifs code bundled
with kernel 2.6.14.2.

Dane