On 4/11/17 5:53 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Add a helper function to xfs_db so that we can recalculate the CRC of an
> inode whose field we just wrote. This enables us to write arbitrary
> values with a good CRC for the purpose of checking the read verifiers on
> a v5 filesystem. Mention this newfound ability in the manpage.
-d isn't new, so I'd really rather have a patch to document the existing
behavior, followed by a patch to extend it to inodes.
There are actually several structures for which -d still won't work, so
it would be good if that fact were documented - reading "including
inodes" may leave some heads scratching.
Let me ruminate on the inode crc writing, I have this nagging feeling
that there's an easier generic way to handle these structures,
...but I'm probably wrong.
Thanks,
-Eric
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> db/io.c | 11 +++++++++++
> db/io.h | 1 +
> db/write.c | 7 ++++++-
> man/man8/xfs_db.8 | 7 ++++++-
> 4 files changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/db/io.c b/db/io.c
> index f398195..67ed5f9 100644
> --- a/db/io.c
> +++ b/db/io.c
> @@ -465,6 +465,17 @@ xfs_dummy_verify(
> }
>
> void
> +xfs_verify_recalc_inode_crc(
> + struct xfs_buf *bp)
> +{
> + ASSERT(iocur_top->ino_buf);
> + ASSERT(iocur_top->bp == bp);
> +
> + libxfs_dinode_calc_crc(mp, iocur_top->data);
> + iocur_top->ino_crc_ok = 1;
> +}
> +
> +void
> xfs_verify_recalc_crc(
> struct xfs_buf *bp)
> {
> diff --git a/db/io.h b/db/io.h
> index c69e9ce..12d96c2 100644
> --- a/db/io.h
> +++ b/db/io.h
> @@ -64,6 +64,7 @@ extern void set_cur(const struct typ *t, __int64_t d, int c, int ring_add,
> extern void ring_add(void);
> extern void set_iocur_type(const struct typ *t);
> extern void xfs_dummy_verify(struct xfs_buf *bp);
> +extern void xfs_verify_recalc_inode_crc(struct xfs_buf *bp);
> extern void xfs_verify_recalc_crc(struct xfs_buf *bp);
>
> /*
> diff --git a/db/write.c b/db/write.c
> index 5c83874..70c9865 100644
> --- a/db/write.c
> +++ b/db/write.c
> @@ -137,7 +137,9 @@ write_f(
> return 0;
> }
>
> - if (invalid_data && iocur_top->typ->crc_off == TYP_F_NO_CRC_OFF) {
> + if (invalid_data &&
> + iocur_top->typ->crc_off == TYP_F_NO_CRC_OFF &&
> + !iocur_top->ino_buf) {
> dbprintf(_("Cannot recalculate CRCs on this type of object\n"));
> return 0;
> }
> @@ -164,6 +166,9 @@ write_f(
> if (corrupt) {
> local_ops.verify_write = xfs_dummy_verify;
> dbprintf(_("Allowing write of corrupted data and bad CRC\n"));
> + } else if (iocur_top->ino_buf) {
> + local_ops.verify_write = xfs_verify_recalc_inode_crc;
> + dbprintf(_("Allowing write of corrupted inode with good CRC\n"));
> } else { /* invalid data */
> local_ops.verify_write = xfs_verify_recalc_crc;
> dbprintf(_("Allowing write of corrupted data with good CRC\n"));
> diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
> index 460d89d..b1c341d 100644
> --- a/man/man8/xfs_db.8
> +++ b/man/man8/xfs_db.8
> @@ -755,7 +755,7 @@ and
> bits respectively, and their string equivalent reported
> (but no modifications are made).
> .TP
> -.BI "write [\-c] [" "field value" "] ..."
> +.BI "write [\-c] [\-d] [" "field value" "] ..."
> Write a value to disk.
> Specific fields can be set in structures (struct mode),
> or a block can be set to data values (data mode),
> @@ -778,6 +778,11 @@ with no arguments gives more information on the allowed commands.
> .B \-c
> Skip write verifiers and CRC recalculation; allows invalid data to be written
> to disk.
> +.TP 0.4i
> +.B \-d
> +Skip write verifiers but perform CRC recalculation.
> +This allows invalid data, including inodes, to be written to disk to
> +test detection of invalid data.
> .RE
> .SH TYPES
> This section gives the fields in each structure type and their meanings.
>
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