Re: surprise behavior #1: ENOENT for existing directories

On 11/30/2009 06:53 PM, Jeff Layton wrote:
> On Mon, 30 Nov 2009 16:45:59 +0530
> Suresh Jayaraman <[email protected]> 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;