[linux-cifs-client] surprise behavior #1: ENOENT for existing directories

[Jeff Layton]

On Mon, 30 Nov 2009 22:14:22 +0530
Suresh Jayaraman <sjayaraman at suse.de> wrote:

> On 11/30/2009 06:53 PM, Jeff Layton wrote:
> > On Mon, 30 Nov 2009 16:45:59 +0530
> > Suresh Jayaraman <sjayaraman at suse.de> wrote:
> > 
> >> On 11/30/2009 07:46 AM, aaron brick wrote:
> >>> i am having two intermittent problems with CIFS and am sending
> >>> separate emails to the list for each. this paragraph is identical. my
> >>> desktop runs debian and kernel 2.6.32rc7; i am mounting a filesystem
> >>> from my synology NAS, running DSM 2.2-0942 and using ext3 & RAID5
> >>> internally. the link is gigabit through cat5e and a netgear switch.
> >>> the only CIFS dmesg entry i see is a couple of: "CIFS VFS: server
> >>> 10.1.1.2 of type Samba 3.2.8 returned unexpected error on SMB posix
> >>> open, disabling posix open support. Check if server update available."
> >>> (FWIW, synology hasn't released a firmware with a more recent samba.)
> >>>
> >>>
> >>> here, creating files within a directory sometimes fails with ENOENT as
> >>> if the parent did not exist. this generally prevents me from using the
> >>> shared filesystem for compilation. an example follows:
> >>>
> >>>
> >>> 11:08 / > mount | grep nas
> >>> //nas/data on /data type cifs (rw,mand)
> >>> 11:08 / > cd data
> >>> 11:08 /data > mkdir a
> >>> 11:08 /data > mkdir a/b
> >>> mkdir: cannot create directory `a/b': No such file or directory
> >>> 11:08 /data > strace mkdir a/b |& grep mkdir
> >>> execve("/bin/mkdir", ["mkdir", "a/b"], [/* 22 vars */]) = 0
> >>> mkdir("a/b", 0777)                      = -1 ENOENT (No such file or directory)
> >>> write(2, "mkdir: ", 7mkdir: )                  = 7
> >>>
> >>
> >> I have not been able to reproduce this 2.6.31-rc1 against Samba 3.2.7. But a
> >> quick look at the code suggests there could be a problem if we do this
> >> sequence:
> >>
> >> POSIX open against Samba server < 3.3.1 (tcon->broken_posix_open will be set)
> >> followed by a mkdir (will call CIFSPOSIXCreate). As we don't seem to check
> >> whether the broken_posix_open is set, this might have led to this issue I think.
> >>
> >> Does the following patch (a quick, untested) fix the issue?
> >>
> >>
> >>
> >>  fs/cifs/inode.c |    3 ++-
> >>  1 files changed, 2 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> >> index cababd8..f1e9ab6 100644
> >> --- a/fs/cifs/inode.c
> >> +++ b/fs/cifs/inode.c
> >> @@ -1038,7 +1038,8 @@ int cifs_mkdir(struct inode *inode, struct dentry *direntry, int mode)
> >>  		return rc;
> >>  	}
> >>  
> >> -	if ((pTcon->ses->capabilities & CAP_UNIX) &&
> >> +	if (!tcon->broken_posix_open && tcon->unix_ext &&
> >              ^^^^ should be "pTcon"
> > 
> 
> Oops, sorry about the not even compile tested patch. Here is the
> compile tested patch. Could you please test this one?
> 
> 
>  fs/cifs/inode.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index cababd8..31be938 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -1038,7 +1038,8 @@ int cifs_mkdir(struct inode *inode, struct dentry *direntry, int mode)
>  		return rc;
>  	}
>  
> -	if ((pTcon->ses->capabilities & CAP_UNIX) &&
> +	if (!pTcon->broken_posix_open && pTcon->unix_ext &&
> +	    (pTcon->ses->capabilities & CAP_UNIX) &&
>  		(CIFS_UNIX_POSIX_PATH_OPS_CAP &
>  			le64_to_cpu(pTcon->fsUnixInfo.Capability))) {
>  		u32 oplock = 0;

Now that I think about it though...

The whole broken_posix_open thing was not a problem for actual creates,
just when opening existing files. I'm pretty sure we still want to use
posix creates for mkdir even if broken_posix_open is set.

I'm more interested to know whether both of these problems go away if
he mounts with "noserverino".

-- 
Jeff Layton <jlayton at samba.org>