From: "Darrick J. Wong" <djwong@kernel.org>
To: Chi Zhiling <chizhiling@163.com>
Cc: cem@kernel.org, linux-xfs@vger.kernel.org,
linux-kernel@vger.kernel.org, Chi Zhiling <chizhiling@kylinos.cn>,
Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH v5] xfs_logprint: Fix super block buffer interpretation issue
Date: Thu, 16 Jan 2025 09:33:50 -0800 [thread overview]
Message-ID: <20250116173350.GA1611770@frogsfrogsfrogs> (raw)
In-Reply-To: <20250116090939.570792-1-chizhiling@163.com>
On Thu, Jan 16, 2025 at 05:09:39PM +0800, Chi Zhiling wrote:
> From: Chi Zhiling <chizhiling@kylinos.cn>
>
> 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
>
> Suggested-by: Darrick J. Wong <djwong@kernel.org>
> Suggested-by: Dave Chinner <david@fromorbit.com>
> Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
I think this looks ok now, though my unaligned-access fu has become weak
since the end of my personal sparc era...
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
--D
> ---
> logprint/log_misc.c | 17 +++++------------
> logprint/log_print_all.c | 22 ++++++++++------------
> 2 files changed, 15 insertions(+), 24 deletions(-)
>
> diff --git a/logprint/log_misc.c b/logprint/log_misc.c
> index 8e86ac34..973bc90c 100644
> --- a/logprint/log_misc.c
> +++ b/logprint/log_misc.c
> @@ -282,22 +282,15 @@ xlog_print_trans_buffer(char **ptr, int len, int *i, int num_ops)
> if (be32_to_cpu(head->oh_len) < 4*8) {
> printf(_("Out of space\n"));
> } else {
> - __be64 a, b;
> + struct xfs_dsb *dsb = (struct xfs_dsb *) *ptr;
>
> printf("\n");
> - /*
> - * memmove because *ptr may not be 8-byte aligned
> - */
> - memmove(&a, *ptr, sizeof(__be64));
> - memmove(&b, *ptr+8, sizeof(__be64));
> 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));
> + (unsigned long long) get_unaligned_be64(&dsb->sb_icount),
> + (unsigned long long) get_unaligned_be64(&dsb->sb_ifree));
> printf(_("fdblks: %llu frext: %llu\n"),
> - (unsigned long long) be64_to_cpu(a),
> - (unsigned long long) be64_to_cpu(b));
> + (unsigned long long) get_unaligned_be64(&dsb->sb_fdblocks),
> + (unsigned long long) get_unaligned_be64(&dsb->sb_frextents));
> }
> super_block = 0;
> } else if (be32_to_cpu(*(__be32 *)(*ptr)) == XFS_AGI_MAGIC) {
> diff --git a/logprint/log_print_all.c b/logprint/log_print_all.c
> index a4a5e41f..cd5fccce 100644
> --- a/logprint/log_print_all.c
> +++ b/logprint/log_print_all.c
> @@ -91,22 +91,20 @@ xlog_recover_print_buffer(
> len = item->ri_buf[i].i_len;
> i++;
> if (blkno == 0) { /* super block */
> + struct xfs_dsb *dsb = (struct xfs_dsb *)p;
> +
> printf(_(" SUPER Block Buffer:\n"));
> if (!print_buffer)
> continue;
> - printf(_(" icount:%llu ifree:%llu "),
> - (unsigned long long)
> - be64_to_cpu(*(__be64 *)(p)),
> - (unsigned long long)
> - be64_to_cpu(*(__be64 *)(p+8)));
> - printf(_("fdblks:%llu frext:%llu\n"),
> - (unsigned long long)
> - be64_to_cpu(*(__be64 *)(p+16)),
> - (unsigned long long)
> - be64_to_cpu(*(__be64 *)(p+24)));
> + printf(_(" icount:%llu ifree:%llu "),
> + (unsigned long long) get_unaligned_be64(&dsb->sb_icount),
> + (unsigned long long) get_unaligned_be64(&dsb->sb_ifree));
> + printf(_("fdblks:%llu frext:%llu\n"),
> + (unsigned long long) get_unaligned_be64(&dsb->sb_fdblocks),
> + (unsigned long long) get_unaligned_be64(&dsb->sb_frextents));
> printf(_(" sunit:%u swidth:%u\n"),
> - be32_to_cpu(*(__be32 *)(p+56)),
> - be32_to_cpu(*(__be32 *)(p+60)));
> + get_unaligned_be32(&dsb->sb_unit),
> + get_unaligned_be32(&dsb->sb_width));
> } else if (be32_to_cpu(*(__be32 *)p) == XFS_AGI_MAGIC) {
> int bucket, buckets;
> agi = (xfs_agi_t *)p;
> --
> 2.43.0
>
>
prev parent reply other threads:[~2025-01-16 17:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-16 9:09 [PATCH v5] xfs_logprint: Fix super block buffer interpretation issue Chi Zhiling
2025-01-16 17:33 ` Darrick J. Wong [this message]
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