diff options
Diffstat (limited to 'fs/xfs/libxfs/xfs_rmap.c')
| -rw-r--r-- | fs/xfs/libxfs/xfs_rmap.c | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c index 9212038d1300..6bed1079e0fe 100644 --- a/fs/xfs/libxfs/xfs_rmap.c +++ b/fs/xfs/libxfs/xfs_rmap.c @@ -400,12 +400,38 @@ xfs_rmap_lookup_le_range( info.irec = irec; info.stat = stat; - trace_xfs_rmap_lookup_le_range(cur->bc_mp, - cur->bc_ag.pag->pag_agno, bno, 0, owner, offset, flags); - error = xfs_rmap_query_range(cur, &info.high, &info.high, - xfs_rmap_lookup_le_range_helper, &info); - if (error == -ECANCELED) - error = 0; + trace_xfs_rmap_lookup_le_range(cur->bc_mp, cur->bc_ag.pag->pag_agno, + bno, 0, owner, offset, flags); + + /* + * Historically, we always used the range query to walk every reverse + * mapping that could possibly overlap the key that the caller asked + * for, and filter out the ones that don't. That is very slow when + * there are a lot of records. + * + * However, there are two scenarios where the classic btree search can + * produce correct results -- if the index contains a record that is an + * exact match for the lookup key; and if there are no other records + * between the record we want and the key we supplied. + * + * As an optimization, try a non-overlapped lookup first. This makes + * scrub run much faster on most filesystems because bmbt records are + * usually an exact match for rmap records. If we don't find what we + * want, we fall back to the overlapped query. + */ + error = xfs_rmap_lookup_le(cur, bno, owner, offset, flags, irec, stat); + if (error) + return error; + if (*stat) { + *stat = 0; + xfs_rmap_lookup_le_range_helper(cur, irec, &info); + } + if (!(*stat)) { + error = xfs_rmap_query_range(cur, &info.high, &info.high, + xfs_rmap_lookup_le_range_helper, &info); + if (error == -ECANCELED) + error = 0; + } if (*stat) trace_xfs_rmap_lookup_le_range_result(cur->bc_mp, cur->bc_ag.pag->pag_agno, irec->rm_startblock, |