On 9/3/19 11:38 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> In rmap_store_ag_btree_rec(), we try to reserve 16 blocks to handle
> adding all the AG btree rmaps to the rmap record. Unfortunately, at
> that point in phase5 we haven't yet reinitialied sb_fdblocks, so
> reserving blocks can fail if repair reconstructed the primary sb from a
> secondary sb. Even if the function succeeds, this still leads to
> incorrect fdblocks because phase 5 resets sb_fdblocks after running the
> rmap transactions.
>
> To avoid all this, move the rmap_store_ag_btree_rec call to after the sb
> has been reset. xfs/350 was helpful in finding cases where xfs_repair
> errored out while repairing the filesystem.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
makes sense to me; would be nice to know what this failure looks like at
repair time tho, for inclusion in the changelog, perhaps.
Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
> repair/phase5.c | 24 +++++++++++++++---------
> 1 file changed, 15 insertions(+), 9 deletions(-)
>
>
> diff --git a/repair/phase5.c b/repair/phase5.c
> index 2e18cc69..7f7d3d18 100644
> --- a/repair/phase5.c
> +++ b/repair/phase5.c
> @@ -2233,7 +2233,6 @@ phase5_func(
> #endif
> xfs_agblock_t num_extents;
> struct agi_stat agi_stat = {0,};
> - int error;
>
> if (verbose)
> do_log(_(" - agno = %d\n"), agno);
> @@ -2426,14 +2425,6 @@ phase5_func(
> finish_cursor(&fino_btree_curs);
> finish_cursor(&bcnt_btree_curs);
>
> - /*
> - * Put the per-AG btree rmap data into the rmapbt
> - */
> - error = rmap_store_ag_btree_rec(mp, agno);
> - if (error)
> - do_error(
> -_("unable to add AG %u reverse-mapping data to btree.\n"), agno);
> -
> /*
> * release the incore per-AG bno/bcnt trees so
> * the extent nodes can be recycled
> @@ -2561,6 +2552,21 @@ phase5(xfs_mount_t *mp)
> */
> sync_sb(mp);
>
> + /*
> + * Put the per-AG btree rmap data into the rmapbt now that we've reset
> + * the superblock counters.
> + */
> + for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
> + error = rmap_store_ag_btree_rec(mp, agno);
> + if (error)
> + do_error(
> +_("unable to add AG %u reverse-mapping data to btree.\n"), agno);
> + }
> +
> + /*
> + * Put blocks that were unnecessarily reserved for btree
> + * reconstruction back into the filesystem free space data.
> + */
> error = inject_lost_blocks(mp, lost_fsb);
> if (error)
> do_error(_("Unable to reinsert lost blocks into filesystem.\n"));
>
