Michael, any objection or comment?
I have seen reports with XFS performance issues too, but I guess it's
possible to solve the problem with uuidd and --cont-clock.
Karel
On Tue, Oct 10, 2023 at 06:08:59PM -0500, Goldwyn Rodrigues wrote:
> Instead of explicitly truncating clocks.txt file, pad with
> whitespaces in the end of file.
> This is done to improve performance of libuuid on xfs
> filesystems. Instead of truncating the file, pad it with whitespaces.
> This is anyways used as a failsafe method in case truncate fails.
>
> The reason why this regression was introduced was because of:
> 869ae85dae64 ("xfs: flush new eof page on truncate to avoid post-eof corruption")
>
> An attempt to move the clocks.txt to /run (tmpfs) has been attempted before
> [1] and with commit ab2e7dd17 ("libuuid: move clock state file from
> /var/lib to /var/run"). The latter was reverted.
>
> [1] https://www.spinics.net/lists/util-linux-ng/msg17331.html
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>
> ---
> libuuid/src/gen_uuid.c | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/libuuid/src/gen_uuid.c b/libuuid/src/gen_uuid.c
> index 619ef0131..97e2dec4e 100644
> --- a/libuuid/src/gen_uuid.c
> +++ b/libuuid/src/gen_uuid.c
> @@ -229,7 +229,6 @@ static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
> struct timeval tv;
> uint64_t clock_reg;
> mode_t save_umask;
> - int len;
> int ret = 0;
>
> if (state_fd == -1)
> @@ -324,14 +323,10 @@ try_again:
>
> if (state_fd >= 0) {
> rewind(state_f);
> - len = fprintf(state_f,
> - "clock: %04x tv: %016ld %08ld adj: %08d\n",
> + fprintf(state_f,
> + "clock: %04x tv: %016ld %08ld adj: %08d \n",
> clock_seq, (long)last.tv_sec, (long)last.tv_usec, adjustment);
> fflush(state_f);
> - if (ftruncate(state_fd, len) < 0) {
> - fprintf(state_f, " \n");
> - fflush(state_f);
> - }
> rewind(state_f);
> flock(state_fd, LOCK_UN);
> }
> --
> 2.42.0
>
>
> --
> Goldwyn
>
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
