[fuse-devel] touch/utimensat returning EINVAL

[Richard W.M. J. <rj...@re...>]

I'm getting a really strange problem with my FUSE module:
http://git.annexia.org/?p=libguestfs.git;a=blob;f=fuse/guestmount.c;hb=HEAD

Sometimes the 'touch' command gets a -EINVAL error from the
'utimensat' syscall.

It only happens reliably when (a) the filesystem has just been mounted
_and_ (b) the following test script is run, _and_ (c) only on the
second iteration of the loop.

----------------------------------------------------------------------
#!/bin/bash -

set -e
set -v

cd /tmp/mnt

while true; do
  for ts in 12345 1234567 987654321; do
    touch -a -d @$ts timestamp
    [ "$(stat -c %X timestamp)" -eq $ts ]
    touch -m -d @$ts timestamp
    [ "$(stat -c %Y timestamp)" -eq $ts ]
    touch    -d @$ts timestamp
    [ "$(stat -c %X timestamp)" -eq $ts ]
    [ "$(stat -c %Y timestamp)" -eq $ts ]
  done
done
----------------------------------------------------------------------

It doesn't happen if the test script is re-run without remounting the
filesystem, nor if I make some apparently trivial modifications to the
test script.

The error seems to happen inside FUSE / kernel, _not_ in any of my
code.  I looked at the kernel code and couldn't see any obvious reason
why (eg.) setattr would return EINVAL.  The trace output of guestmount
is below.  I'm using fuse-2.8.5-2.fc14.x86_64 (compiled for Fedora 14)
and kernel 2.6.35.9-64.fc14.x86_64.

Any ideas?

Rich.

Bug report: https://bugzilla.redhat.com/show_bug.cgi?id=660687

----------------------------------------------------------------------
set_recovery_proc true = 0
add_drive_opts "test1.img" = 0
launch = 0
mount_options "" "/dev/sda1" "/" = 0
umask 0 = 18
guestmount: fg_getattr (/.Trash, 0x7fff5104bba0)
lstat "/.Trash" = NULL (error)
guestmount: fg_getattr (/.Trash-500, 0x7fff5104bba0)
lstat "/.Trash-500" = NULL (error)
guestmount: fg_getattr (/, 0x7fff5104bb70)
lstat "/" = <struct guestfs_stat *>
guestmount: fg_access (/, 1)
guestmount: fg_getattr (/, 0x7fff5104bb90)
lstat "/" = <struct guestfs_stat *>
guestmount: fg_getattr (/timestamp, 0x7fff5104bba0)
lstat "/timestamp" = <struct guestfs_stat *>
guestmount: fg_open (/timestamp, 0104001)
guestmount: fg_utimens (/timestamp, [{ 12345, 0 }, { 987654321, 0 }])
utimens "/timestamp" 12345 0 987654321 0 = 0
guestmount: fg_getattr (/timestamp, 0x7fff5104bac0)
lstat "/timestamp" = <struct guestfs_stat *>
guestmount: fg_release (/timestamp)
guestmount: fg_open (/timestamp, 0104001)
guestmount: fg_release (/timestamp)
----------------------------------------------------------------------

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
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