xfs: allow the user to cancel repairs before we start writing

All online repair functions have the same structure: walk filesystem
metadata structures gathering enough data to rebuild the structure,
stage a new copy, and then commit the new copy.

The gathering steps do not write anything to disk, so they are peppered
with xchk_should_terminate calls to avoid softlockup warnings and to
provide an opportunity to abort the repair (by killing xfs_scrub).
However, it's not clear in the code base when is the last chance to
abort cleanly without having to undo a bunch of structure.

Therefore, add one more call to xchk_should_terminate (along with a
comment) providing the sysadmin with the ability to abort before it's
too late and to make it clear in the source code when it's no longer
convenient or safe to abort a repair.   As there are only four repair
functions right now, this patch exists more to establish a precedent for
subsequent additions than to deliver practical functionality.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Darrick J. Wong 2023-08-10 07:48:10 -07:00
parent d65eb8a633
commit d728f4e3b2

View file

@ -49,6 +49,10 @@ xrep_superblock(
if (error)
return error;
/* Last chance to abort before we start committing fixes. */
if (xchk_should_terminate(sc, &error))
return error;
/* Copy AG 0's superblock to this one. */
xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
xfs_sb_to_disk(bp->b_addr, &mp->m_sb);
@ -424,6 +428,10 @@ xrep_agf(
if (error)
return error;
/* Last chance to abort before we start committing fixes. */
if (xchk_should_terminate(sc, &error))
return error;
/* Start rewriting the header and implant the btrees we found. */
xrep_agf_init_header(sc, agf_bp, &old_agf);
xrep_agf_set_roots(sc, agf, fab);
@ -748,6 +756,10 @@ xrep_agfl(
if (error)
goto err;
/* Last chance to abort before we start committing fixes. */
if (xchk_should_terminate(sc, &error))
goto err;
/*
* Update AGF and AGFL. We reset the global free block counter when
* we adjust the AGF flcount (which can fail) so avoid updating any
@ -995,6 +1007,10 @@ xrep_agi(
if (error)
return error;
/* Last chance to abort before we start committing fixes. */
if (xchk_should_terminate(sc, &error))
return error;
/* Start rewriting the header and implant the btrees we found. */
xrep_agi_init_header(sc, agi_bp, &old_agi);
xrep_agi_set_roots(sc, agi, fab);