Tracks smbd aborts on GlusterFS 11.x triggered by the fix for bug 16043 (4.23.7, 4.24.2, master) while the upstream fix gluster/glusterfs#4798 is pending.

Root cause (upstream): libgfapi's glfs_*at() calls release the parent directory handle twice when a lookup fails with anything other than ENOENT, so the handle smbd still holds is freed (gluster/glusterfs#4796; fix proposed with a regression test in
  gluster/glusterfs#4798, under review). Present in every 11.x release since the *at() API arrived in 11.0 (2022). The change is confined to api/src/glfs-fops.c and applies unchanged to release-11 (v11.2).

How smbd reaches it: vfs_gluster_fstatat()/vfs_gluster_openat() pass the directory handle as the at()-parent (since 4.17.0, bug 15157), and directory listings issue SMB_VFS_FSTATAT() relative to the open directory handle (since 4.19.0; 4.20.0 added   the pathref opens relative to it). One entry failing with ENOTDIR, EACCES, or ENOTCONN during a transport disconnect frees the directory handle behind smbd's back.

Effect of the 16043 fix: closing the handle at session logoff turns an existing silent invalid-handle state (the listing returned EBADF for the rest of the session and the handle leaked) into an abort in pub_glfs_close() <- vfs_gluster_fsp_ext_destroy() once the allocator has reused the block, which is the normal case in a busy smbd.

Observed on a production gateway (Samba 4.23.6 with the 16043 backport, GlusterFS 11.2):
    * 11 smbd cores in two days across 6 clients
    * 10 at session logoff, in pub_glfs_close() from the destructor
    * 1 in pub_glfs_openat() relative to an already freed parent

Stable branches: reverting bug 16043 restores the unbounded fd leak and does not prevent the openat-relative crash. If the fix is kept, a known-issue entry for 4.23.x/4.24.x would tell affected sites what to do while libgfapi is unfixed. Distributions that ship both projects can carry the glfs-fops.c change in their libgfapi package.

Evidence in gluster/glusterfs#4796: ASan traces of the double release for openat/fstatat/renameat/renameat2, a reproducer, the regression test (fails on unfixed devel, passes with the fix), and the smbd backtraces. Available to test patches or  backports on the affected gateway.