On Fri, Oct 11, 2024 at 11:08:10AM +0800, Chi Zhiling wrote:
> From: chizhiling <chizhiling@xxxxxxxxxx>
>
> When using xfs_logprint to interpret the buffer of the super block, the
> icount will always be 6360863066640355328 (0x5846534200001000). This is
> because the offset of icount is incorrect, causing xfs_logprint to
> misinterpret the MAGIC number as icount.
> This patch fixes the offset value of the SB counters in xfs_logprint.
>
> Before this patch:
> icount: 6360863066640355328 ifree: 5242880 fdblks: 0 frext: 0
>
> After this patch:
> icount: 10240 ifree: 4906 fdblks: 37 frext: 0
>
> Signed-off-by: chizhiling <chizhiling@xxxxxxxxxx>
> ---
> logprint/log_misc.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/logprint/log_misc.c b/logprint/log_misc.c
> index 8e86ac34..21da5b8b 100644
> --- a/logprint/log_misc.c
> +++ b/logprint/log_misc.c
> @@ -288,13 +288,13 @@ xlog_print_trans_buffer(char **ptr, int len, int *i, int num_ops)
> /*
> * memmove because *ptr may not be 8-byte aligned
> */
> - memmove(&a, *ptr, sizeof(__be64));
> - memmove(&b, *ptr+8, sizeof(__be64));
How did this ever work?? This even looks wrong in "Release_1.0.0".
> + memmove(&a, *ptr + offsetof(struct xfs_dsb, sb_icount), sizeof(__be64));
> + memmove(&b, *ptr + offsetof(struct xfs_dsb, sb_ifree), sizeof(__be64));
Why not do:
struct xfs_dsb *dsb = *ptr;
memcpy(&a, &dsb->sb_icount, sizeof(a));
or better yet, skip the indirection and do
printf(_("icount: %llu ifree: %llu "),
(unsigned long long)be64_to_cpu(dsb->sb_icount),
(unsigned long long)be64_to_cpu(dsb->sb_ifree));
Hm?
--D
> printf(_("icount: %llu ifree: %llu "),
> (unsigned long long) be64_to_cpu(a),
> (unsigned long long) be64_to_cpu(b));
> - memmove(&a, *ptr+16, sizeof(__be64));
> - memmove(&b, *ptr+24, sizeof(__be64));
> + memmove(&a, *ptr + offsetof(struct xfs_dsb, sb_fdblocks), sizeof(__be64));
> + memmove(&b, *ptr + offsetof(struct xfs_dsb, sb_frextents), sizeof(__be64));
> printf(_("fdblks: %llu frext: %llu\n"),
> (unsigned long long) be64_to_cpu(a),
> (unsigned long long) be64_to_cpu(b));
> --
> 2.43.0
>
