On Sun, Aug 14, 2016 at 07:30:51PM -0500, Eric Sandeen wrote:
> This adds a new "crc" command to xfs_db for CRC-enabled filesystems.
>
> If a structure has a CRC field, we can validate it, invalidate/corrupt
> it, or revalidate/rewrite it:
>
> xfs_db> sb 0
> xfs_db> crc -v
> crc = 0x796c814f (correct)
> xfs_db> crc -i
> Metadata CRC error detected at block 0x0/0x200
> crc = 0x796c8150 (bad)
> xfs_db> crc -r
> crc = 0x796c814f (correct)
>
> (-i and -r require "expert" write-capable mode)
>
> This requires temporarily replacing the write verifier with
> a dummy which won't recalculate the CRC on the way to disk.
>
> It also required me to write a new flist function, which is
> totally foreign to me, so hopefully done right - but it seems
> to work here.
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Actually, this need more help....
> @@ -473,12 +474,15 @@ xfs_verify_recalc_crc(
> void
> write_cur(void)
> {
> + int skip_crc = (iocur_top->bp->b_ops->verify_write == xfs_dummy_verify);
> +
bool, and we can't use the iocur until we've checked if it's valid.
i.e. after this first check:
> if (iocur_sp < 0) {
> dbprintf(_("nothing to write\n"));
> return;
> }
>
> - if (xfs_sb_version_hascrc(&mp->m_sb) && iocur_top->ino_buf) {
> + if (xfs_sb_version_hascrc(&mp->m_sb) && iocur_top->ino_buf &&
> + !skip_crc) {
> libxfs_dinode_calc_crc(mp, iocur_top->data);
> iocur_top->ino_crc_ok = 1;
> }
The line of code below this calculates CRCs for dquot buffers, so it
seems kind of broken to be skipping crc update for an inode but not
a dquot given they are updated in the same way....
Shouldn't this "skip_crc" condition also be applied to dquot
buffers, too?
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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