[Gluster-devel] weird response of gluster_readdir

[Shehjar Tikoo]

Dongmin Yu wrote:
> Hello,
> 
>  
> 
> I’m using glusterfs-2.0.4 and building a c-program with libglusterfsclient.
> 
>  
> 
> I’ve created a directory, ‘test’ and wrote a file, ‘hello.txt’, to the 
> directory on glusterfs mounted volume.
> 
> Then I wanted to list all the files/sub-directories in the directory.
> 
>  
> 
> My code was as followings,
> 
>  
> 
> ======
> 
> struct dirent *dirp = NULL;
> 
> glusterfs_dir_t dirfd = NULL;
> 
> char *path = “/gfs_mount/test/”;
> 
>  
> 
> dirfd = glusterfs_opendir(path);
> 

Before you can use libglusterfsclient API, you need to set up
a few things using the glusterfs_mount call. If that wasnt done,
glusterfs_opendir should have returned a NULL, thats the first
bug here I think. Can you confirm if you called glusterfs_mount
in the full program?

Have you looked at booster? It is a library that you LD_PRELOAD
under your regular applications so that file system access
happens over libglusterfsclient, without the need to adapt
apps to libglusterfsclient.
For more info, see 
http://www.gluster.org/docs/index.php/BoosterConfiguration

-Shehjar

> while( (dirp = glusterfs_readdir(dirfd) != NULL) ){
> 
> printf("## %s %d %d\n", dirp->d_name, dirp->d_type, dirp->d_reclen  );
> 
>         for( i = 0 ; i < 256; i++ ){
> 
>             printf("%d ", dirp->d_name[i]);
> 
>         }
> 
>         printf("\n");}
> 
> glusterfs_closedir(dirfd);
> 
> =====
> 
>  
> 
> What I expected result was,
> 
> ## Hello.txt 8 24
> 
> ## . 4 16
> 
> ## .. 4 16
> 
>  
> 
> But
> 
> ##  0 74
> 
> 0 0 0 0 0 0 0 0 46 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0
> 
> ##  0 24578
> 
> 0 0 0 0 0 0 0 0 46 46 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0
> 
> ## | 135 48751
> 
> 124 0 0 0 0 0 0 0 104 101 108 108 111 46 116 120 116 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
> 0 0 0 0 0 0 0 0 0 0 0 0 0
> 
>  
> 
> As you see, first 8 bytes has garbage data and d_type value is not correct.
> 
>  
> 
> Is it a bug of readdir or am I mis-using the library?
> 
>  
> 
> Thanks
> 
>  
> 
> *DongMin Yu*
> 
>  
> 
> HOSTWAY IDC Corp. / R&D Principal Researcher
> 
> TEL. +822 2105 6037
> 
> FAX. +822 2105 6019
> 
> CELL. +8216 2086 1357
> 
> EMAIL: min.yu at hostwaycorp.com <mailto:min.yu at hostwaycorp.com>
> 
> Website: http://www.hostway.com
> 
>  
> 
> *NOTICE:  This email and any file transmitted are confidential and/or 
> legally privileged and intended only for the person(s) directly 
> addressed.  If you are not the intended recipient, any use, copying, 
> transmission, distribution, or other forms of dissemination is strictly 
> prohibited.  If you have received this email in error, please notify the 
> sender immediately and permanently delete the email and files, if any.*
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Gluster-devel mailing list
> Gluster-devel at nongnu.org
> http://lists.nongnu.org/mailman/listinfo/gluster-devel