There have been reports of log messages like:
automount[nnnn]: handle_packet_expire_direct: can't find map entry for (1048647,114082)
These messages are fatal because the direct mount path must be known to
lookup the mount. Historically the autofs kernel communication packet
size is fixed and based on the maximum path name component size used by
indirect mounts but direct mounts have a variable length multi-component
path. To solve this while maintaining compatability with indirect mounts,
an index of (device, inode) tuples is maintained to allow lookup of the
direct mount path so the map entry can be located.
Also it's necessary to understand that direct mount maps are always read
fully in order to mount direct mount triggers for all direct mount map
entries so they must exist so this approach should always work.
So the message above only occurs for direct mounts and the ioctl file
handle used by each direct mount is stored in the map entry so it's
not possibile to respond to the kernel at all if the map entry cache
entry can't be found.
Unfortunately map entry cache cleanup on update is complicated and can
lead to problems which (I believe) is what's happening here.
While I suspect your reproducer is a different case to what I've seen
it probably symtomatic of the underlying problem.
Patches "autofs-5.1.9 - fix devid update on reload" and "autofs-5.1.9
- fix stale direct mount trigger not umounted on expire" are the main
fixes I was able to identify working through the code.
Please test them and let me know how it goes.
Note: The CHANGELOG hunks will conflict so you'll need to compensate
for that.
Ian
Ian Kent (9):
autofs-5.1.9 - quiet possibly noisy log message
autofs-5.1.9 - fix devid update on reload
autofs-5.1.9 - fix cache writelock must be taken in update_map_cache()
autofs-5.1.9 - fix skip valid map entries on expire cleanup
autofs-5.1.9 - remove unnecessary call to
set_direct_mount_tree_catatonic()
autofs-5.1.9 - remove unnecessary assignment in umount_multi()
autofs-5.1.9 - fix direct mount trigger umount failure case
autofs-5.1.9 - refactor do_umount_autofs_direct()
autofs-5.1.9 - fix stale direct mount trigger not umounted on expire
CHANGELOG | 9 +++
daemon/automount.c | 35 +++++-------
daemon/direct.c | 130 ++++++++++++++++++++++++++------------------
daemon/lookup.c | 33 ++++-------
daemon/state.c | 17 ++----
include/automount.h | 2 +-
lib/mounts.c | 1 -
7 files changed, 118 insertions(+), 109 deletions(-)
--
2.50.1
