His operations are affected by this bug.

Certain directories on gluster filesystem periodically change from mode 0755 to mode 0644. Needless to say, a directory of mode 0644 does not work very well.

It is of course possible that some program in the system is explicitly
chmod'ing the directory to remove the execute bit. However, this problem is not seen on Gluster 2.x. This behavior is seen on Drupal Gardens after Gardens  switched to Gluster 3.0.4.

Further supporting the glusterfs bug theory are these lines from
/var/log/glusterfs/etc-glusterfs-glusterfsd.vol.log, examples of which seem to appear exactly once each time a directory mysteriously changes to not having the execute bit set any more:

[2010-05-19 13:59:05] E [posix.c:2366:posix_open] posix1: open on
/mnt/brick1/theirc/sites/default/files/ctools/css: Is a directory
[2010-05-19 13:59:05] E [posix.c:2146:posix_truncate] posix1: truncate on
/theirc/sites/default/files/ctools/css failed: Is a directory
[2010-05-19 13:59:05] E [posix.c:2366:posix_open] posix1: open on
/mnt/brick1/theirc/sites/default/files/ctools/css: Is a directory


Please find the attached server logs with the bug.

Can we get the client logs from there as well?

PATCH: http://patches.gluster.com/patch/3317 in release-3.0 (Set op_ret to -1 when open fails in posix_open)

PATCH: http://patches.gluster.com/patch/3320 in master (resolver: set safer conditionals during path creation)

PATCH: http://patches.gluster.com/patch/3321 in release-3.0 (resolver: set safer conditionals during path creation)

PATCH: http://patches.gluster.com/patch/5055 in master (resolver: set safer conditionals during path creation)