xfs: scrub directory/attribute btrees
authorDarrick J. Wong <darrick.wong@oracle.com>
Wed, 18 Oct 2017 04:37:43 +0000 (21:37 -0700)
committerDarrick J. Wong <darrick.wong@oracle.com>
Thu, 26 Oct 2017 22:38:25 +0000 (15:38 -0700)
Provide a way to check the shape and scrub the hashes and records
in a directory or extended attribute btree.  These are helper functions
for the directory & attribute scrubbers in subsequent patches.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
[fengguang: remove unneeded variable to store return value]
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
fs/xfs/Makefile
fs/xfs/scrub/dabtree.c [new file with mode: 0644]
fs/xfs/scrub/dabtree.h [new file with mode: 0644]

index df86fc5..f4eca58 100644 (file)
@@ -148,6 +148,7 @@ xfs-y                               += $(addprefix scrub/, \
                                   bmap.o \
                                   btree.o \
                                   common.o \
+                                  dabtree.o \
                                   ialloc.o \
                                   inode.o \
                                   refcount.o \
diff --git a/fs/xfs/scrub/dabtree.c b/fs/xfs/scrub/dabtree.c
new file mode 100644 (file)
index 0000000..4a93cf1
--- /dev/null
@@ -0,0 +1,588 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_inode_fork.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_dir2.h"
+#include "xfs_dir2_priv.h"
+#include "xfs_attr_leaf.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+#include "scrub/dabtree.h"
+
+/* Directory/Attribute Btree */
+
+/*
+ * Check for da btree operation errors.  See the section about handling
+ * operational errors in common.c.
+ */
+bool
+xfs_scrub_da_process_error(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level,
+       int                             *error)
+{
+       struct xfs_scrub_context        *sc = ds->sc;
+
+       if (*error == 0)
+               return true;
+
+       switch (*error) {
+       case -EDEADLOCK:
+               /* Used to restart an op with deadlock avoidance. */
+               trace_xfs_scrub_deadlock_retry(sc->ip, sc->sm, *error);
+               break;
+       case -EFSBADCRC:
+       case -EFSCORRUPTED:
+               /* Note the badness but don't abort. */
+               sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+               *error = 0;
+               /* fall through */
+       default:
+               trace_xfs_scrub_file_op_error(sc, ds->dargs.whichfork,
+                               xfs_dir2_da_to_db(ds->dargs.geo,
+                                       ds->state->path.blk[level].blkno),
+                               *error, __return_address);
+               break;
+       }
+       return false;
+}
+
+/*
+ * Check for da btree corruption.  See the section about handling
+ * operational errors in common.c.
+ */
+void
+xfs_scrub_da_set_corrupt(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level)
+{
+       struct xfs_scrub_context        *sc = ds->sc;
+
+       sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+
+       trace_xfs_scrub_fblock_error(sc, ds->dargs.whichfork,
+                       xfs_dir2_da_to_db(ds->dargs.geo,
+                               ds->state->path.blk[level].blkno),
+                       __return_address);
+}
+
+/* Find an entry at a certain level in a da btree. */
+STATIC void *
+xfs_scrub_da_btree_entry(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level,
+       int                             rec)
+{
+       char                            *ents;
+       struct xfs_da_state_blk         *blk;
+       void                            *baddr;
+
+       /* Dispatch the entry finding function. */
+       blk = &ds->state->path.blk[level];
+       baddr = blk->bp->b_addr;
+       switch (blk->magic) {
+       case XFS_ATTR_LEAF_MAGIC:
+       case XFS_ATTR3_LEAF_MAGIC:
+               ents = (char *)xfs_attr3_leaf_entryp(baddr);
+               return ents + (rec * sizeof(struct xfs_attr_leaf_entry));
+       case XFS_DIR2_LEAFN_MAGIC:
+       case XFS_DIR3_LEAFN_MAGIC:
+               ents = (char *)ds->dargs.dp->d_ops->leaf_ents_p(baddr);
+               return ents + (rec * sizeof(struct xfs_dir2_leaf_entry));
+       case XFS_DIR2_LEAF1_MAGIC:
+       case XFS_DIR3_LEAF1_MAGIC:
+               ents = (char *)ds->dargs.dp->d_ops->leaf_ents_p(baddr);
+               return ents + (rec * sizeof(struct xfs_dir2_leaf_entry));
+       case XFS_DA_NODE_MAGIC:
+       case XFS_DA3_NODE_MAGIC:
+               ents = (char *)ds->dargs.dp->d_ops->node_tree_p(baddr);
+               return ents + (rec * sizeof(struct xfs_da_node_entry));
+       }
+
+       return NULL;
+}
+
+/* Scrub a da btree hash (key). */
+int
+xfs_scrub_da_btree_hash(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level,
+       __be32                          *hashp)
+{
+       struct xfs_da_state_blk         *blks;
+       struct xfs_da_node_entry        *entry;
+       xfs_dahash_t                    hash;
+       xfs_dahash_t                    parent_hash;
+
+       /* Is this hash in order? */
+       hash = be32_to_cpu(*hashp);
+       if (hash < ds->hashes[level])
+               xfs_scrub_da_set_corrupt(ds, level);
+       ds->hashes[level] = hash;
+
+       if (level == 0)
+               return 0;
+
+       /* Is this hash no larger than the parent hash? */
+       blks = ds->state->path.blk;
+       entry = xfs_scrub_da_btree_entry(ds, level - 1, blks[level - 1].index);
+       parent_hash = be32_to_cpu(entry->hashval);
+       if (parent_hash < hash)
+               xfs_scrub_da_set_corrupt(ds, level);
+
+       return 0;
+}
+
+/*
+ * Check a da btree pointer.  Returns true if it's ok to use this
+ * pointer.
+ */
+STATIC bool
+xfs_scrub_da_btree_ptr_ok(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level,
+       xfs_dablk_t                     blkno)
+{
+       if (blkno < ds->lowest || (ds->highest != 0 && blkno >= ds->highest)) {
+               xfs_scrub_da_set_corrupt(ds, level);
+               return false;
+       }
+
+       return true;
+}
+
+/*
+ * The da btree scrubber can handle leaf1 blocks as a degenerate
+ * form of leafn blocks.  Since the regular da code doesn't handle
+ * leaf1, we must multiplex the verifiers.
+ */
+static void
+xfs_scrub_da_btree_read_verify(
+       struct xfs_buf          *bp)
+{
+       struct xfs_da_blkinfo   *info = bp->b_addr;
+
+       switch (be16_to_cpu(info->magic)) {
+       case XFS_DIR2_LEAF1_MAGIC:
+       case XFS_DIR3_LEAF1_MAGIC:
+               bp->b_ops = &xfs_dir3_leaf1_buf_ops;
+               bp->b_ops->verify_read(bp);
+               return;
+       default:
+               /*
+                * xfs_da3_node_buf_ops already know how to handle
+                * DA*_NODE, ATTR*_LEAF, and DIR*_LEAFN blocks.
+                */
+               bp->b_ops = &xfs_da3_node_buf_ops;
+               bp->b_ops->verify_read(bp);
+               return;
+       }
+}
+static void
+xfs_scrub_da_btree_write_verify(
+       struct xfs_buf          *bp)
+{
+       struct xfs_da_blkinfo   *info = bp->b_addr;
+
+       switch (be16_to_cpu(info->magic)) {
+       case XFS_DIR2_LEAF1_MAGIC:
+       case XFS_DIR3_LEAF1_MAGIC:
+               bp->b_ops = &xfs_dir3_leaf1_buf_ops;
+               bp->b_ops->verify_write(bp);
+               return;
+       default:
+               /*
+                * xfs_da3_node_buf_ops already know how to handle
+                * DA*_NODE, ATTR*_LEAF, and DIR*_LEAFN blocks.
+                */
+               bp->b_ops = &xfs_da3_node_buf_ops;
+               bp->b_ops->verify_write(bp);
+               return;
+       }
+}
+
+static const struct xfs_buf_ops xfs_scrub_da_btree_buf_ops = {
+       .name = "xfs_scrub_da_btree",
+       .verify_read = xfs_scrub_da_btree_read_verify,
+       .verify_write = xfs_scrub_da_btree_write_verify,
+};
+
+/* Check a block's sibling. */
+STATIC int
+xfs_scrub_da_btree_block_check_sibling(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level,
+       int                             direction,
+       xfs_dablk_t                     sibling)
+{
+       int                             retval;
+       int                             error;
+
+       memcpy(&ds->state->altpath, &ds->state->path,
+                       sizeof(ds->state->altpath));
+
+       /*
+        * If the pointer is null, we shouldn't be able to move the upper
+        * level pointer anywhere.
+        */
+       if (sibling == 0) {
+               error = xfs_da3_path_shift(ds->state, &ds->state->altpath,
+                               direction, false, &retval);
+               if (error == 0 && retval == 0)
+                       xfs_scrub_da_set_corrupt(ds, level);
+               error = 0;
+               goto out;
+       }
+
+       /* Move the alternate cursor one block in the direction given. */
+       error = xfs_da3_path_shift(ds->state, &ds->state->altpath,
+                       direction, false, &retval);
+       if (!xfs_scrub_da_process_error(ds, level, &error))
+               return error;
+       if (retval) {
+               xfs_scrub_da_set_corrupt(ds, level);
+               return error;
+       }
+
+       /* Compare upper level pointer to sibling pointer. */
+       if (ds->state->altpath.blk[level].blkno != sibling)
+               xfs_scrub_da_set_corrupt(ds, level);
+       xfs_trans_brelse(ds->dargs.trans, ds->state->altpath.blk[level].bp);
+out:
+       return error;
+}
+
+/* Check a block's sibling pointers. */
+STATIC int
+xfs_scrub_da_btree_block_check_siblings(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level,
+       struct xfs_da_blkinfo           *hdr)
+{
+       xfs_dablk_t                     forw;
+       xfs_dablk_t                     back;
+       int                             error = 0;
+
+       forw = be32_to_cpu(hdr->forw);
+       back = be32_to_cpu(hdr->back);
+
+       /* Top level blocks should not have sibling pointers. */
+       if (level == 0) {
+               if (forw != 0 || back != 0)
+                       xfs_scrub_da_set_corrupt(ds, level);
+               return 0;
+       }
+
+       /*
+        * Check back (left) and forw (right) pointers.  These functions
+        * absorb error codes for us.
+        */
+       error = xfs_scrub_da_btree_block_check_sibling(ds, level, 0, back);
+       if (error)
+               goto out;
+       error = xfs_scrub_da_btree_block_check_sibling(ds, level, 1, forw);
+
+out:
+       memset(&ds->state->altpath, 0, sizeof(ds->state->altpath));
+       return error;
+}
+
+/* Load a dir/attribute block from a btree. */
+STATIC int
+xfs_scrub_da_btree_block(
+       struct xfs_scrub_da_btree       *ds,
+       int                             level,
+       xfs_dablk_t                     blkno)
+{
+       struct xfs_da_state_blk         *blk;
+       struct xfs_da_intnode           *node;
+       struct xfs_da_node_entry        *btree;
+       struct xfs_da3_blkinfo          *hdr3;
+       struct xfs_da_args              *dargs = &ds->dargs;
+       struct xfs_inode                *ip = ds->dargs.dp;
+       xfs_ino_t                       owner;
+       int                             *pmaxrecs;
+       struct xfs_da3_icnode_hdr       nodehdr;
+       int                             error;
+
+       blk = &ds->state->path.blk[level];
+       ds->state->path.active = level + 1;
+
+       /* Release old block. */
+       if (blk->bp) {
+               xfs_trans_brelse(dargs->trans, blk->bp);
+               blk->bp = NULL;
+       }
+
+       /* Check the pointer. */
+       blk->blkno = blkno;
+       if (!xfs_scrub_da_btree_ptr_ok(ds, level, blkno))
+               goto out_nobuf;
+
+       /* Read the buffer. */
+       error = xfs_da_read_buf(dargs->trans, dargs->dp, blk->blkno, -2,
+                       &blk->bp, dargs->whichfork,
+                       &xfs_scrub_da_btree_buf_ops);
+       if (!xfs_scrub_da_process_error(ds, level, &error))
+               goto out_nobuf;
+
+       /*
+        * We didn't find a dir btree root block, which means that
+        * there's no LEAF1/LEAFN tree (at least not where it's supposed
+        * to be), so jump out now.
+        */
+       if (ds->dargs.whichfork == XFS_DATA_FORK && level == 0 &&
+                       blk->bp == NULL)
+               goto out_nobuf;
+
+       /* It's /not/ ok for attr trees not to have a da btree. */
+       if (blk->bp == NULL) {
+               xfs_scrub_da_set_corrupt(ds, level);
+               goto out_nobuf;
+       }
+
+       hdr3 = blk->bp->b_addr;
+       blk->magic = be16_to_cpu(hdr3->hdr.magic);
+       pmaxrecs = &ds->maxrecs[level];
+
+       if (hdr3->hdr.pad != cpu_to_be16(0))
+               xfs_scrub_da_set_corrupt(ds, level);
+
+       /* Check the owner. */
+       if (xfs_sb_version_hascrc(&ip->i_mount->m_sb)) {
+               owner = be64_to_cpu(hdr3->owner);
+               if (owner != ip->i_ino)
+                       xfs_scrub_da_set_corrupt(ds, level);
+       }
+
+       /* Check the siblings. */
+       error = xfs_scrub_da_btree_block_check_siblings(ds, level, &hdr3->hdr);
+       if (error)
+               goto out;
+
+       /* Interpret the buffer. */
+       switch (blk->magic) {
+       case XFS_ATTR_LEAF_MAGIC:
+       case XFS_ATTR3_LEAF_MAGIC:
+               xfs_trans_buf_set_type(dargs->trans, blk->bp,
+                               XFS_BLFT_ATTR_LEAF_BUF);
+               blk->magic = XFS_ATTR_LEAF_MAGIC;
+               blk->hashval = xfs_attr_leaf_lasthash(blk->bp, pmaxrecs);
+               if (ds->tree_level != 0)
+                       xfs_scrub_da_set_corrupt(ds, level);
+               break;
+       case XFS_DIR2_LEAFN_MAGIC:
+       case XFS_DIR3_LEAFN_MAGIC:
+               xfs_trans_buf_set_type(dargs->trans, blk->bp,
+                               XFS_BLFT_DIR_LEAFN_BUF);
+               blk->magic = XFS_DIR2_LEAFN_MAGIC;
+               blk->hashval = xfs_dir2_leaf_lasthash(ip, blk->bp, pmaxrecs);
+               if (ds->tree_level != 0)
+                       xfs_scrub_da_set_corrupt(ds, level);
+               break;
+       case XFS_DIR2_LEAF1_MAGIC:
+       case XFS_DIR3_LEAF1_MAGIC:
+               xfs_trans_buf_set_type(dargs->trans, blk->bp,
+                               XFS_BLFT_DIR_LEAF1_BUF);
+               blk->magic = XFS_DIR2_LEAF1_MAGIC;
+               blk->hashval = xfs_dir2_leaf_lasthash(ip, blk->bp, pmaxrecs);
+               if (ds->tree_level != 0)
+                       xfs_scrub_da_set_corrupt(ds, level);
+               break;
+       case XFS_DA_NODE_MAGIC:
+       case XFS_DA3_NODE_MAGIC:
+               xfs_trans_buf_set_type(dargs->trans, blk->bp,
+                               XFS_BLFT_DA_NODE_BUF);
+               blk->magic = XFS_DA_NODE_MAGIC;
+               node = blk->bp->b_addr;
+               ip->d_ops->node_hdr_from_disk(&nodehdr, node);
+               btree = ip->d_ops->node_tree_p(node);
+               *pmaxrecs = nodehdr.count;
+               blk->hashval = be32_to_cpu(btree[*pmaxrecs - 1].hashval);
+               if (level == 0) {
+                       if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH) {
+                               xfs_scrub_da_set_corrupt(ds, level);
+                               goto out_freebp;
+                       }
+                       ds->tree_level = nodehdr.level;
+               } else {
+                       if (ds->tree_level != nodehdr.level) {
+                               xfs_scrub_da_set_corrupt(ds, level);
+                               goto out_freebp;
+                       }
+               }
+
+               /* XXX: Check hdr3.pad32 once we know how to fix it. */
+               break;
+       default:
+               xfs_scrub_da_set_corrupt(ds, level);
+               goto out_freebp;
+       }
+
+out:
+       return error;
+out_freebp:
+       xfs_trans_brelse(dargs->trans, blk->bp);
+       blk->bp = NULL;
+out_nobuf:
+       blk->blkno = 0;
+       return error;
+}
+
+/* Visit all nodes and leaves of a da btree. */
+int
+xfs_scrub_da_btree(
+       struct xfs_scrub_context        *sc,
+       int                             whichfork,
+       xfs_scrub_da_btree_rec_fn       scrub_fn)
+{
+       struct xfs_scrub_da_btree       ds = {};
+       struct xfs_mount                *mp = sc->mp;
+       struct xfs_da_state_blk         *blks;
+       struct xfs_da_node_entry        *key;
+       void                            *rec;
+       xfs_dablk_t                     blkno;
+       int                             level;
+       int                             error;
+
+       /* Skip short format data structures; no btree to scan. */
+       if (XFS_IFORK_FORMAT(sc->ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
+           XFS_IFORK_FORMAT(sc->ip, whichfork) != XFS_DINODE_FMT_BTREE)
+               return 0;
+
+       /* Set up initial da state. */
+       ds.dargs.dp = sc->ip;
+       ds.dargs.whichfork = whichfork;
+       ds.dargs.trans = sc->tp;
+       ds.dargs.op_flags = XFS_DA_OP_OKNOENT;
+       ds.state = xfs_da_state_alloc();
+       ds.state->args = &ds.dargs;
+       ds.state->mp = mp;
+       ds.sc = sc;
+       if (whichfork == XFS_ATTR_FORK) {
+               ds.dargs.geo = mp->m_attr_geo;
+               ds.lowest = 0;
+               ds.highest = 0;
+       } else {
+               ds.dargs.geo = mp->m_dir_geo;
+               ds.lowest = ds.dargs.geo->leafblk;
+               ds.highest = ds.dargs.geo->freeblk;
+       }
+       blkno = ds.lowest;
+       level = 0;
+
+       /* Find the root of the da tree, if present. */
+       blks = ds.state->path.blk;
+       error = xfs_scrub_da_btree_block(&ds, level, blkno);
+       if (error)
+               goto out_state;
+       /*
+        * We didn't find a block at ds.lowest, which means that there's
+        * no LEAF1/LEAFN tree (at least not where it's supposed to be),
+        * so jump out now.
+        */
+       if (blks[level].bp == NULL)
+               goto out_state;
+
+       blks[level].index = 0;
+       while (level >= 0 && level < XFS_DA_NODE_MAXDEPTH) {
+               /* Handle leaf block. */
+               if (blks[level].magic != XFS_DA_NODE_MAGIC) {
+                       /* End of leaf, pop back towards the root. */
+                       if (blks[level].index >= ds.maxrecs[level]) {
+                               if (level > 0)
+                                       blks[level - 1].index++;
+                               ds.tree_level++;
+                               level--;
+                               continue;
+                       }
+
+                       /* Dispatch record scrubbing. */
+                       rec = xfs_scrub_da_btree_entry(&ds, level,
+                                       blks[level].index);
+                       error = scrub_fn(&ds, level, rec);
+                       if (error)
+                               break;
+                       if (xfs_scrub_should_terminate(sc, &error) ||
+                           (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
+                               break;
+
+                       blks[level].index++;
+                       continue;
+               }
+
+
+               /* End of node, pop back towards the root. */
+               if (blks[level].index >= ds.maxrecs[level]) {
+                       if (level > 0)
+                               blks[level - 1].index++;
+                       ds.tree_level++;
+                       level--;
+                       continue;
+               }
+
+               /* Hashes in order for scrub? */
+               key = xfs_scrub_da_btree_entry(&ds, level, blks[level].index);
+               error = xfs_scrub_da_btree_hash(&ds, level, &key->hashval);
+               if (error)
+                       goto out;
+
+               /* Drill another level deeper. */
+               blkno = be32_to_cpu(key->before);
+               level++;
+               ds.tree_level--;
+               error = xfs_scrub_da_btree_block(&ds, level, blkno);
+               if (error)
+                       goto out;
+               if (blks[level].bp == NULL)
+                       goto out;
+
+               blks[level].index = 0;
+       }
+
+out:
+       /* Release all the buffers we're tracking. */
+       for (level = 0; level < XFS_DA_NODE_MAXDEPTH; level++) {
+               if (blks[level].bp == NULL)
+                       continue;
+               xfs_trans_brelse(sc->tp, blks[level].bp);
+               blks[level].bp = NULL;
+       }
+
+out_state:
+       xfs_da_state_free(ds.state);
+       return error;
+}
diff --git a/fs/xfs/scrub/dabtree.h b/fs/xfs/scrub/dabtree.h
new file mode 100644 (file)
index 0000000..2a766de
--- /dev/null
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef __XFS_SCRUB_DABTREE_H__
+#define __XFS_SCRUB_DABTREE_H__
+
+/* dir/attr btree */
+
+struct xfs_scrub_da_btree {
+       struct xfs_da_args              dargs;
+       xfs_dahash_t                    hashes[XFS_DA_NODE_MAXDEPTH];
+       int                             maxrecs[XFS_DA_NODE_MAXDEPTH];
+       struct xfs_da_state             *state;
+       struct xfs_scrub_context        *sc;
+
+       /*
+        * Lowest and highest directory block address in which we expect
+        * to find dir/attr btree node blocks.  For a directory this
+        * (presumably) means between LEAF_OFFSET and FREE_OFFSET; for
+        * attributes there is no limit.
+        */
+       xfs_dablk_t                     lowest;
+       xfs_dablk_t                     highest;
+
+       int                             tree_level;
+};
+
+typedef int (*xfs_scrub_da_btree_rec_fn)(struct xfs_scrub_da_btree *ds,
+               int level, void *rec);
+
+/* Check for da btree operation errors. */
+bool xfs_scrub_da_process_error(struct xfs_scrub_da_btree *ds, int level, int *error);
+
+/* Check for da btree corruption. */
+void xfs_scrub_da_set_corrupt(struct xfs_scrub_da_btree *ds, int level);
+
+int xfs_scrub_da_btree_hash(struct xfs_scrub_da_btree *ds, int level,
+                           __be32 *hashp);
+int xfs_scrub_da_btree(struct xfs_scrub_context *sc, int whichfork,
+                      xfs_scrub_da_btree_rec_fn scrub_fn);
+
+#endif /* __XFS_SCRUB_DABTREE_H__ */