diff options
Diffstat (limited to 'fs/xfs/scrub/repair.c')
| -rw-r--r-- | fs/xfs/scrub/repair.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/fs/xfs/scrub/repair.c b/fs/xfs/scrub/repair.c index 7daf0120d1bf..877488ce4bc8 100644 --- a/fs/xfs/scrub/repair.c +++ b/fs/xfs/scrub/repair.c @@ -836,3 +836,193 @@ out: xfs_repair_cancel_btree_extents(sc, exlist); return error; } + +/* + * Finding per-AG Btree Roots for AGF/AGI Reconstruction + * + * If the AGF or AGI become slightly corrupted, it may be necessary to rebuild + * the AG headers by using the rmap data to rummage through the AG looking for + * btree roots. This is not guaranteed to work if the AG is heavily damaged + * or the rmap data are corrupt. + * + * Callers of xfs_repair_find_ag_btree_roots must lock the AGF and AGFL + * buffers if the AGF is being rebuilt; or the AGF and AGI buffers if the + * AGI is being rebuilt. It must maintain these locks until it's safe for + * other threads to change the btrees' shapes. The caller provides + * information about the btrees to look for by passing in an array of + * xfs_repair_find_ag_btree with the (rmap owner, buf_ops, magic) fields set. + * The (root, height) fields will be set on return if anything is found. The + * last element of the array should have a NULL buf_ops to mark the end of the + * array. + * + * For every rmapbt record matching any of the rmap owners in btree_info, + * read each block referenced by the rmap record. If the block is a btree + * block from this filesystem matching any of the magic numbers and has a + * level higher than what we've already seen, remember the block and the + * height of the tree required to have such a block. When the call completes, + * we return the highest block we've found for each btree description; those + * should be the roots. + */ + +struct xfs_repair_findroot { + struct xfs_scrub_context *sc; + struct xfs_buf *agfl_bp; + struct xfs_agf *agf; + struct xfs_repair_find_ag_btree *btree_info; +}; + +/* See if our block is in the AGFL. */ +STATIC int +xfs_repair_findroot_agfl_walk( + struct xfs_mount *mp, + xfs_agblock_t bno, + void *priv) +{ + xfs_agblock_t *agbno = priv; + + return (*agbno == bno) ? XFS_BTREE_QUERY_RANGE_ABORT : 0; +} + +/* Does this block match the btree information passed in? */ +STATIC int +xfs_repair_findroot_block( + struct xfs_repair_findroot *ri, + struct xfs_repair_find_ag_btree *fab, + uint64_t owner, + xfs_agblock_t agbno, + bool *found_it) +{ + struct xfs_mount *mp = ri->sc->mp; + struct xfs_buf *bp; + struct xfs_btree_block *btblock; + xfs_daddr_t daddr; + int error; + + daddr = XFS_AGB_TO_DADDR(mp, ri->sc->sa.agno, agbno); + + /* + * Blocks in the AGFL have stale contents that might just happen to + * have a matching magic and uuid. We don't want to pull these blocks + * in as part of a tree root, so we have to filter out the AGFL stuff + * here. If the AGFL looks insane we'll just refuse to repair. + */ + if (owner == XFS_RMAP_OWN_AG) { + error = xfs_agfl_walk(mp, ri->agf, ri->agfl_bp, + xfs_repair_findroot_agfl_walk, &agbno); + if (error == XFS_BTREE_QUERY_RANGE_ABORT) + return 0; + if (error) + return error; + } + + error = xfs_trans_read_buf(mp, ri->sc->tp, mp->m_ddev_targp, daddr, + mp->m_bsize, 0, &bp, NULL); + if (error) + return error; + + /* + * Does this look like a block matching our fs and higher than any + * other block we've found so far? If so, reattach buffer verifiers + * so the AIL won't complain if the buffer is also dirty. + */ + btblock = XFS_BUF_TO_BLOCK(bp); + if (be32_to_cpu(btblock->bb_magic) != fab->magic) + goto out; + if (xfs_sb_version_hascrc(&mp->m_sb) && + !uuid_equal(&btblock->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid)) + goto out; + bp->b_ops = fab->buf_ops; + + /* Ignore this block if it's lower in the tree than we've seen. */ + if (fab->root != NULLAGBLOCK && + xfs_btree_get_level(btblock) < fab->height) + goto out; + + /* Make sure we pass the verifiers. */ + bp->b_ops->verify_read(bp); + if (bp->b_error) + goto out; + fab->root = agbno; + fab->height = xfs_btree_get_level(btblock) + 1; + *found_it = true; + + trace_xfs_repair_findroot_block(mp, ri->sc->sa.agno, agbno, + be32_to_cpu(btblock->bb_magic), fab->height - 1); +out: + xfs_trans_brelse(ri->sc->tp, bp); + return error; +} + +/* + * Do any of the blocks in this rmap record match one of the btrees we're + * looking for? + */ +STATIC int +xfs_repair_findroot_rmap( + struct xfs_btree_cur *cur, + struct xfs_rmap_irec *rec, + void *priv) +{ + struct xfs_repair_findroot *ri = priv; + struct xfs_repair_find_ag_btree *fab; + xfs_agblock_t b; + bool found_it; + int error = 0; + + /* Ignore anything that isn't AG metadata. */ + if (!XFS_RMAP_NON_INODE_OWNER(rec->rm_owner)) + return 0; + + /* Otherwise scan each block + btree type. */ + for (b = 0; b < rec->rm_blockcount; b++) { + found_it = false; + for (fab = ri->btree_info; fab->buf_ops; fab++) { + if (rec->rm_owner != fab->rmap_owner) + continue; + error = xfs_repair_findroot_block(ri, fab, + rec->rm_owner, rec->rm_startblock + b, + &found_it); + if (error) + return error; + if (found_it) + break; + } + } + + return 0; +} + +/* Find the roots of the per-AG btrees described in btree_info. */ +int +xfs_repair_find_ag_btree_roots( + struct xfs_scrub_context *sc, + struct xfs_buf *agf_bp, + struct xfs_repair_find_ag_btree *btree_info, + struct xfs_buf *agfl_bp) +{ + struct xfs_mount *mp = sc->mp; + struct xfs_repair_findroot ri; + struct xfs_repair_find_ag_btree *fab; + struct xfs_btree_cur *cur; + int error; + + ASSERT(xfs_buf_islocked(agf_bp)); + ASSERT(agfl_bp == NULL || xfs_buf_islocked(agfl_bp)); + + ri.sc = sc; + ri.btree_info = btree_info; + ri.agf = XFS_BUF_TO_AGF(agf_bp); + ri.agfl_bp = agfl_bp; + for (fab = btree_info; fab->buf_ops; fab++) { + ASSERT(agfl_bp || fab->rmap_owner != XFS_RMAP_OWN_AG); + ASSERT(XFS_RMAP_NON_INODE_OWNER(fab->rmap_owner)); + fab->root = NULLAGBLOCK; + fab->height = 0; + } + + cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno); + error = xfs_rmap_query_all(cur, xfs_repair_findroot_rmap, &ri); + xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR); + + return error; +} |
