On 2023-04-12 We 10:23, Dagfinn Ilmari Mannsåker wrote:
Andrew Dunstan <andrew@dunslane.net> writes:
On 2023-04-12 We 01:48, Thomas Munro wrote:
On Wed, Apr 12, 2023 at 3:04 PM Thomas Munro<thomas.munro@gmail.com> wrote:
On Wed, Apr 12, 2023 at 2:56 PM Christoph Berg<myon@debian.org> wrote:
I'm hitting a panic in t_004_io_direct. The build is running on
overlayfs on tmpfs/ext4 (upper/lower) which is probably a weird
combination but has worked well for building everything over the last
decade. On Debian unstable:
PANIC: could not open file "pg_wal/000000010000000000000001": Invalid argument
... I have a new idea: perhaps it is possible to try
to open a file with O_DIRECT from perl, and if it fails like that,
skip the test. Looking into that now.
I think I have that working OK. Any Perl hackers want to comment on
my use of IO::File (copied from examples on the internet that showed
how to use O_DIRECT)? I am not much of a perl hacker but according to
my package manager, IO/File.pm came with perl itself. And the Fcntl
eval trick that I copied from File::stat, and the perl-critic
suppression that requires?
I think you can probably replace a lot of the magic here by simply saying
if (Fcntl->can("O_DIRECT")) ...
Fcntl->can() is true for all constants that Fcntl knows about, whether
or not they are defined for your OS. `defined &O_DIRECT` is the simplest
check, see my other reply to Thomas.
My understanding was that Fcntl only exported constants known to the OS. That's certainly what its docco suggests, e.g.:
By default your system's F_* and O_* constants (eg, F_DUPFD and O_CREAT)
and the FD_CLOEXEC constant are exported into your namespace.
cheers
andrew
--
Andrew Dunstan
EDB: https://www.enterprisedb.com
