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xfs: disable reaping in fscounters scrub

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The fscounters scrub code doesn't work properly because it cannot
quiesce updates to the percpu counters in the filesystem, hence it
returns false corruption reports.  This has been fixed properly in
one of the online repair patchsets that are under review by replacing
the xchk_disable_reaping calls with an exclusive filesystem freeze.
Disabling background gc isn't sufficient to fix the problem.

In other words, scrub doesn't need to call xfs_inodegc_stop, which is
just as well since it wasn't correct to allow scrub to call
xfs_inodegc_start when something else could be calling xfs_inodegc_stop
(e.g. trying to freeze the filesystem).

Neuter the scrubber for now, and remove the xchk_*_reaping functions.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Darrick J. Wong 2023-05-02 09:16:14 +10:00 committed by Dave Chinner
parent b37c4c8339
commit 2d5f38a319
6 changed files with 6 additions and 39 deletions
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26
fs/xfs/scrub/common.c
View file

@ -1164,32 +1164,6 @@ xchk_metadata_inode_forks(
return 0;
}
/* Pause background reaping of resources. */
void
xchk_stop_reaping(
struct xfs_scrub *sc)
{
sc->flags |= XCHK_REAPING_DISABLED;
xfs_blockgc_stop(sc->mp);
xfs_inodegc_stop(sc->mp);
}
/* Restart background reaping of resources. */
void
xchk_start_reaping(
struct xfs_scrub *sc)
{
/*
* Readonly filesystems do not perform inactivation or speculative
* preallocation, so there's no need to restart the workers.
*/
if (!xfs_is_readonly(sc->mp)) {
xfs_inodegc_start(sc->mp);
xfs_blockgc_start(sc->mp);
}
sc->flags &= ~XCHK_REAPING_DISABLED;
}
/*
* Enable filesystem hooks (i.e. runtime code patching) before starting a scrub
* operation. Callers must not hold any locks that intersect with the CPU

2
fs/xfs/scrub/common.h
View file

@ -156,8 +156,6 @@ static inline bool xchk_skip_xref(struct xfs_scrub_metadata *sm)
}
int xchk_metadata_inode_forks(struct xfs_scrub *sc);
void xchk_stop_reaping(struct xfs_scrub *sc);
void xchk_start_reaping(struct xfs_scrub *sc);
/*
* Setting up a hook to wait for intents to drain is costly -- we have to take

13
fs/xfs/scrub/fscounters.c
View file

@ -150,13 +150,6 @@ xchk_setup_fscounters(
if (error)
return error;
/*
* Pause background reclaim while we're scrubbing to reduce the
* likelihood of background perturbations to the counters throwing off
* our calculations.
*/
xchk_stop_reaping(sc);
return xchk_trans_alloc(sc, 0);
}
@ -453,6 +446,12 @@ xchk_fscounters(
if (frextents > mp->m_sb.sb_rextents)
xchk_set_corrupt(sc);
/*
* XXX: We can't quiesce percpu counter updates, so exit early.
* This can be re-enabled when we gain exclusive freeze functionality.
*/
return 0;
/*
* If ifree exceeds icount by more than the minimum variance then
* something's probably wrong with the counters.

2
fs/xfs/scrub/scrub.c
View file

@ -186,8 +186,6 @@ xchk_teardown(
}
if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
mnt_drop_write_file(sc->file);
if (sc->flags & XCHK_REAPING_DISABLED)
xchk_start_reaping(sc);
if (sc->buf) {
if (sc->buf_cleanup)
sc->buf_cleanup(sc->buf);

1
fs/xfs/scrub/scrub.h
View file

@ -106,7 +106,6 @@ struct xfs_scrub {
/* XCHK state flags grow up from zero, XREP state flags grown down from 2^31 */
#define XCHK_TRY_HARDER (1 << 0) /* can't get resources, try again */
#define XCHK_REAPING_DISABLED (1 << 1) /* background block reaping paused */
#define XCHK_FSGATES_DRAIN (1 << 2) /* defer ops draining enabled */
#define XCHK_NEED_DRAIN (1 << 3) /* scrub needs to drain defer ops */
#define XREP_ALREADY_FIXED (1 << 31) /* checking our repair work */

1
fs/xfs/scrub/trace.h
View file

@ -98,7 +98,6 @@ TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_FSCOUNTERS);
#define XFS_SCRUB_STATE_STRINGS \
{ XCHK_TRY_HARDER, "try_harder" }, \
{ XCHK_REAPING_DISABLED, "reaping_disabled" }, \
{ XCHK_FSGATES_DRAIN, "fsgates_drain" }, \
{ XCHK_NEED_DRAIN, "need_drain" }, \
{ XREP_ALREADY_FIXED, "already_fixed" }