[Gluster-devel] Question regarding to gluster and vfs
srangana at redhat.com
Thu Aug 17 11:46:21 UTC 2017
On 08/17/2017 07:36 AM, Amar Tumballi wrote:
> On Thu, Aug 17, 2017 at 1:21 PM, Raghavendra Talur <rtalur at redhat.com
> <mailto:rtalur at redhat.com>> wrote:
> On Wed, Aug 16, 2017 at 5:52 PM, Ilan Schwarts <ilan84 at gmail.com
> <mailto:ilan84 at gmail.com>> wrote:
> > Hi,
> > So this is a bit odd case.
> > I have created 2 servers nodes (running CentOS 7.3)
> > From Client machine (CentOS 7.2) I mount to one of the nodes
> (nfs) using:
> > [root at CentOS7286-64 mnt]# mount -t nfs
> > L137B-GlusterFS-Node1.L137B-root.com:/volume1 /mnt/glustervianfs/
> > When i created (touch) a file over the NFS:
> > From Client Machine:
> > [revivo at CentOS7286-64 glustervianfs]$ touch nfs3file
> > [revivo at CentOS7286-64 glustervianfs]$ id revivo
> > uid=2021(revivo) gid=2020(maccabi) groups=2020(maccabi),10(wheel)
> > On Server machine:
> > I monitor the file operations at VFS kernel level.
> > I receive 1 event of file create, and 2 events of set attribute
> > What I see is that root creates the file (uid/gid of 0)
> > And then root (also) use chown and chgrp to set security (attribute)
> > of the new file.
> > When i go to the glutser volume itself and ls -la,i do see the
> > *correct* (2021 - revivo /2020 - revivo) uid/gid:
> > [root at L137B-GlusterFS-Node1 volume1]# ls -lia
> > total 24
> > 11 drwxrwxrwx. 3 revivo maccabi 4096 Aug 10 12:13 .
> > 2 drwxr-xr-x. 3 root root 4096 Aug 9 14:32 ..
> > 12 drw-------. 16 root root 4096 Aug 10 12:13 .glusterfs
> > 31 -rw-r--r--. 2 revivo maccabi 0 Aug 10 12:13 nfs3file
> > Why on the VFS layer i get uid/gid - 0/0
> As you have pointed out above, the file is created with 0:0
> owner:group but subsequent operations change owner and group using
> chown and chgrp. This is because the glusterfsd(brick daemon) process
> always runs as root. I don't know the exact reason why setfsuid and
> setfsgid are not used although the code exist.
> Do you know why HAVE_SET_FSID is undefined in line
> Its been ~10 years since its disabled in codebase, and I don't recollect
> why completely right now.
> By checking the patch  which got this change, I couldn't make out
> much: Probably something to do with Solaris support IMO.
>  -
> May be time to run a test by removing that line as we are friendly with
> only Linux/BSD right now.
From memory (so take it with a pinch of salt), setting internal xattrs
and the like needed root permissions, and not UID/GID permissions, this
was when parts of DHT xattr setting was fixed and this code path
analyzed (about less than a year back).
So when testing it out this possibly needs some consideration. @Nithya
do you have a better context to provide?
> Raghavendra Talur
> Amar Tumballi (amarts)
> Gluster-devel mailing list
> Gluster-devel at gluster.org
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