diff options
Diffstat (limited to 'fs/xfs/xfs_btree.c')
-rw-r--r-- | fs/xfs/xfs_btree.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c index 36477aae77d..75a8a7b00df 100644 --- a/fs/xfs/xfs_btree.c +++ b/fs/xfs/xfs_btree.c @@ -3059,3 +3059,115 @@ error0: XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR); return error; } + +/* + * Try to merge a non-leaf block back into the inode root. + * + * Note: the killroot names comes from the fact that we're effectively + * killing the old root block. But because we can't just delete the + * inode we have to copy the single block it was pointing to into the + * inode. + */ +int +xfs_btree_kill_iroot( + struct xfs_btree_cur *cur) +{ + int whichfork = cur->bc_private.b.whichfork; + struct xfs_inode *ip = cur->bc_private.b.ip; + struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork); + struct xfs_btree_block *block; + struct xfs_btree_block *cblock; + union xfs_btree_key *kp; + union xfs_btree_key *ckp; + union xfs_btree_ptr *pp; + union xfs_btree_ptr *cpp; + struct xfs_buf *cbp; + int level; + int index; + int numrecs; +#ifdef DEBUG + union xfs_btree_ptr ptr; + int i; +#endif + + XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY); + + ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE); + ASSERT(cur->bc_nlevels > 1); + + /* + * Don't deal with the root block needs to be a leaf case. + * We're just going to turn the thing back into extents anyway. + */ + level = cur->bc_nlevels - 1; + if (level == 1) + goto out0; + + /* + * Give up if the root has multiple children. + */ + block = xfs_btree_get_iroot(cur); + if (xfs_btree_get_numrecs(block) != 1) + goto out0; + + cblock = xfs_btree_get_block(cur, level - 1, &cbp); + numrecs = xfs_btree_get_numrecs(cblock); + + /* + * Only do this if the next level will fit. + * Then the data must be copied up to the inode, + * instead of freeing the root you free the next level. + */ + if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level)) + goto out0; + + XFS_BTREE_STATS_INC(cur, killroot); + +#ifdef DEBUG + xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB); + ASSERT(xfs_btree_ptr_is_null(cur, &ptr)); + xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB); + ASSERT(xfs_btree_ptr_is_null(cur, &ptr)); +#endif + + index = numrecs - cur->bc_ops->get_maxrecs(cur, level); + if (index) { + xfs_iroot_realloc(cur->bc_private.b.ip, index, + cur->bc_private.b.whichfork); + block = (struct xfs_btree_block *)ifp->if_broot; + } + + be16_add_cpu(&block->bb_numrecs, index); + ASSERT(block->bb_numrecs == cblock->bb_numrecs); + + kp = xfs_btree_key_addr(cur, 1, block); + ckp = xfs_btree_key_addr(cur, 1, cblock); + xfs_btree_copy_keys(cur, kp, ckp, numrecs); + + pp = xfs_btree_ptr_addr(cur, 1, block); + cpp = xfs_btree_ptr_addr(cur, 1, cblock); +#ifdef DEBUG + for (i = 0; i < numrecs; i++) { + int error; + + error = xfs_btree_check_ptr(cur, cpp, i, level - 1); + if (error) { + XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR); + return error; + } + } +#endif + xfs_btree_copy_ptrs(cur, pp, cpp, numrecs); + + cur->bc_ops->free_block(cur, cbp); + XFS_BTREE_STATS_INC(cur, free); + + cur->bc_bufs[level - 1] = NULL; + be16_add_cpu(&block->bb_level, -1); + xfs_trans_log_inode(cur->bc_tp, ip, + XFS_ILOG_CORE | XFS_ILOG_FBROOT(cur->bc_private.b.whichfork)); + cur->bc_nlevels--; +out0: + XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT); + return 0; +} |