[Gluster-devel] cannot delete non-empty directory

Mon Feb 9 17:50:28 UTC 2015

----- Original Message -----
> From: "David F. Robinson" <david.robinson at corvidtec.com>
> To: "Shyam" <srangana at redhat.com>, "Gluster Devel" <gluster-devel at gluster.org>, gluster-users at gluster.org, "Susant
> Palai" <spalai at redhat.com>
> Sent: Monday, February 9, 2015 10:55:44 PM
> Subject: Re: [Gluster-devel] cannot delete non-empty directory
> 
> So, just to be sure before I do this, it is okay to do the following if
> I want to get rid of everything in the /old_shelf4/Aegis directory and
> below?
> 
>   rm -rf /data/brick*/homegfs_bkp/backup.0/old_shelf4/Aegis

Yes. This will solve the issue you are facing now. After this Aegis can be removed from the mount point.

> 
> What happens to all of the files in the .glusterfs directory?  Does this
> get rebuilt or do the links stay there for files that now no longer
> exist?

Links stay there for files that now no longer exist. This is not an issue except that we'll be loosing an inode (no data-blocks as file size was 0).

> 
> And, is this same issue what causes all of the broken links in
> .glusterfs.  See attached image for example.  There appears to be a lot
> of broken links the .glusterfs directories.  Is this normal or does it
> indicate another problem.

There can be other issues which can result in links not getting deleted from .glusterfs directory. Current issue is not related to that.

> 
> Finally, if I search through the /data/brick* directories, should I find
> no entries of "-------T" permission files with zero length files?  Do I
> need to clean all of these up somehow?  A quick look at
> /data/brick01bkp/homegfs_bkp/.glusterfs/2f/54 shows many of these files.
>   They look like
> ---------T   3 rbhinge      pme_ics           0 Jan  9 16:45
> 2f54d7d6-968b-442f-8cfe-eff01d6cefe7
> ---------T   2 rbhinge      pme_ics           0 Jan  9 21:40
> 2f54d7e7-b198-4fd4-aec7-f5d0ff020f72
> 
> How do I find out what file these entries were pointing to?

As shyam had mentioned in an earlier mail, these files represent dht "linkto" files. These are sort of metadata containing the name of the subvolume where actual file is stored (hence the name "link-to"). The destination to which this "linkto" is pointing is stored in xattrs. A dump of all the xattrs matching regex "trusted.glusterfs.*" should list all the xattrs. The value of "trusted.glusterfs.dht.linkto" xattr should give the destination subvolume. If the file is not present on the destination, then its a stale linkto file pointing to non-existent file (on destination subvol) and it can be removed. Otherwise they are valid and shouldn't be removed.

Again as shyam mentioned in previous mail [1] should've fixed the issue (it is present in v3.6.0 and above). Not sure why we are seeing this issue again.

[1] http://review.gluster.org/8602

> 
> David
> 
> 
> 
> 
> ------ Original Message ------
> From: "Shyam" <srangana at redhat.com>
> To: "David F. Robinson" <david.robinson at corvidtec.com>; "Gluster Devel"
> <gluster-devel at gluster.org>; "gluster-users at gluster.org"
> <gluster-users at gluster.org>; "Susant Palai" <spalai at redhat.com>
> Sent: 2/9/2015 11:11:20 AM
> Subject: Re: [Gluster-devel] cannot delete non-empty directory
> 
> >On 02/08/2015 12:19 PM, David F. Robinson wrote:
> >>I am seeing these messsages after I delete large amounts of data using
> >>gluster 3.6.2.
> >>cannot delete non-empty directory:
> >>old_shelf4/Aegis/!!!Programs/RavenCFD/Storage/Jimmy_Old/src_vj1.5_final
> >>*_From the FUSE mount (as root), the directory shows up as empty:_*
> >># pwd
> >>/backup/homegfs/backup.0/old_shelf4/Aegis/!!!Programs/RavenCFD/Storage/Jimmy_Old/src_vj1.5_final
> >>
> >># ls -al
> >>total 5
> >>d--------- 2 root root 4106 Feb 6 13:55 .
> >>drwxrws--- 3 601 dmiller 72 Feb 6 13:55 ..
> >>However, when you look at the bricks, the files are still there (none
> >>on
> >>brick01bkp, all files are on brick02bkp). All of the files are
> >>0-length
> >>and have ------T permissions.
> >
> >These files are linkto files that are created by DHT, which basically
> >mean the files were either renamed, or the brick layout changed (I
> >suspect the former to be the cause).
> >
> >These files should have been deleted when the files that they point to
> >were deleted, looks like this did not happen.
> >
> >Can I get the following information for some of the files here,
> >- getfattr -d -m . -e text <path to file on brick>
> >   - The output of trusted.glusterfs.dht.linkto xattr should state where
> >the real file belongs, in this case as there are only 2 bricks, it
> >should be brick01bkp subvol
> >- As the second brick is empty, we should be able to safely delete
> >these files from the brick and proceed to do an rmdir on the mount
> >point of the volume as the directory is now empty.
> >- Please check, the one sub-directory that is showing up in this case
> >as well, "save1"
> >
> >>Any suggestions on how to fix this and how to prevent it from
> >>happening?
> >
> >I believe there are renames happening here, possibly by the archive
> >creator, one way to prevent the rename from creating a linkto file is
> >to use the DHT set parameter to set a pattern so that file name hash
> >considers only the static part of the name.
> >
> >The set parameter is, cluster.extra-hash-regex.
> >
> >A link on a similar problem and how to use this set parameter (there a
> >few in the gluster forums) would be,
> >http://www.gluster.org/pipermail/gluster-devel/2014-November/042863.html
> >
> >Additionally, there is a bug here, the unlink of the file should have
> >cleaned up the linkto as well, so that all of the above is not
> >required, we have noticed this with NFS and FUSE mounts (ref bugs,
> >1117923, 1139992), and investigation is in progress on the same. We
> >will step up the priority on this so that we have a clean fix that can
> >be used to prevent this in the future.
> >
> >Shyam
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