[GIT PULL] afs: Fix oops and confusion from metadata xattrs

[David Howells]

Hi Linus,

Can you pull these two fixes to the afs filesystem please?

 (1) Fix an oops in AFS that can be triggered by accessing one of the
     afs.yfs.* xattrs against an OpenAFS server - for instance by "cp
     -a"[1], "rsync -X" or getfattr[2].  These try and copy all of the
     xattrs.

     cp and rsync should pay attention to the list in /etc/xattr.conf, but
     cp doesn't on Ubuntu and rsync doesn't seem to on Ubuntu or Fedora.
     xattr.conf has been modified upstream[3], and a new version has just
     been cut that includes it.  I've logged a bug against rsync for the
     problem there[4].

 (2) Stop listing "afs.*" xattrs[6], particularly ACL ones[8] so that they
     don't confuse cp and rsync.  This removes them from the list returned
     by listxattr(), but they're still available to get/set.

Changes:
ver #2:
 - Hide all of the afs.* xattrs, not just the ACL ones[7].

David

Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003498.html [1]
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003501.html [2]
Link: https://git.savannah.nongnu.org/cgit/attr.git/commit/?id=74da517cc655a82ded715dea7245ce88ebc91b98 [3]
Link: https://github.com/WayneD/rsync/issues/163 [4]
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003516.html [5]
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003524.html [6]
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003565.html # v1
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003568.html [7]
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003570.html [8]
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003571.html # v2
---
The following changes since commit a38fd8748464831584a19438cbb3082b5a2dab15:

  Linux 5.12-rc2 (2021-03-05 17:33:41 -0800)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git tags/afs-fixes-20210315

for you to fetch changes up to a7889c6320b9200e3fe415238f546db677310fa9:

  afs: Stop listxattr() from listing "afs.*" attributes (2021-03-15 17:09:54 +0000)

----------------------------------------------------------------
AFS fixes

----------------------------------------------------------------
David Howells (2):
      afs: Fix accessing YFS xattrs on a non-YFS server
      afs: Stop listxattr() from listing "afs.*" attributes

 fs/afs/dir.c          |  1 -
 fs/afs/file.c         |  1 -
 fs/afs/fs_operation.c |  7 +++++--
 fs/afs/inode.c        |  1 -
 fs/afs/internal.h     |  1 -
 fs/afs/mntpt.c        |  1 -
 fs/afs/xattr.c        | 31 +++++++------------------------
 7 files changed, 12 insertions(+), 31 deletions(-)