[Gluster-users] 答复: does Gluster support O_DIRECT ?

Bill Bao bill at uit.com.cn
Wed Mar 14 16:46:43 UTC 2012

Thanks Deepak, one more question:


Can we export a FUSE mounted volume (on gluster client) to be a NAS backend

thus the client can act as a NAS server with file distribution capability.




发件人: Deepak C Shetty [mailto:deepakcs at linux.vnet.ibm.com] 
发送时间: Wednesday, March 14, 2012 11:44 PM
收件人: Bill Bao
抄送: gluster-users at gluster.org
主题: Re: [Gluster-users] does Gluster support O_DIRECT ?


On 03/14/2012 07:29 AM, Bill Bao wrote: 

This might be a question asked before, but I just couldn’t effectively
search the whole archives,

So please bear me and kindly advise.


We have a 3rd party application (video streaming kind of) which uses
directIO (O_DIRECT).

On the server side, in the posix translator, we added the “option o-direct

On the client side, we mounted as “mount -t glusterfs -o
direct-io-mode=enable server1:/test-volume /mnt/glusterfs”


But the application still fails with error (cannot create/open file with


Then we trace to the fuse module in the kernel, which has following


int fuse_open_common(struct inode *inode, struct file *file, bool isdir)


        struct fuse_conn *fc = get_fuse_conn(inode);

        int err;

        /* VFS checks this, but only _after_ ->open() */

        if (file->f_flags & O_DIRECT)

                return -EINVAL;

        err = generic_file_open(inode, file);


looks like regardless what we configure on the gluster side, the FUSE still
rejects the O_DIRECT.

Could someone shed light ? we’re also trying to take out the O_DIRECT
checking in FUSE module,

to see what will happen, will report soon.


Bill Bao


O_DIRECT support for fuse was added recently. Check the fsdevel archives.





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