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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
  * Copyright (c) 2013 Red Hat, Inc.
  * All Rights Reserved.
  */
 #include "xfs.h"
 #include "xfs_fs.h"
 #include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_bit.h"
 #include "xfs_mount.h"
 #include "xfs_inode.h"
 #include "xfs_dir2.h"
 #include "xfs_dir2_priv.h"
 #include "xfs_trans.h"
 #include "xfs_bmap.h"
 #include "xfs_attr_leaf.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
 #include "xfs_buf_item.h"
 #include "xfs_log.h"
 #include "xfs_errortag.h"
 
 /*
  * xfs_da_btree.c
  *
  * Routines to implement directories as Btrees of hashed names.
  */
 
 /*========================================================================
  * Function prototypes for the kernel.
  *========================================================================*/
 
 /*
  * Routines used for growing the Btree.
  */
 STATIC int xfs_da3_root_split(xfs_da_state_t *state,
                         xfs_da_state_blk_t *existing_root,
                         xfs_da_state_blk_t *new_child);
 STATIC int xfs_da3_node_split(xfs_da_state_t *state,
                         xfs_da_state_blk_t *existing_blk,
                         xfs_da_state_blk_t *split_blk,
                         xfs_da_state_blk_t *blk_to_add,
                         int treelevel,
                         int *result);
 STATIC void xfs_da3_node_rebalance(xfs_da_state_t *state,
                      xfs_da_state_blk_t *node_blk_1,
                      xfs_da_state_blk_t *node_blk_2);
 STATIC void xfs_da3_node_add(xfs_da_state_t *state,
                    xfs_da_state_blk_t *old_node_blk,
                    xfs_da_state_blk_t *new_node_blk);
 
 /*
  * Routines used for shrinking the Btree.
  */
 STATIC int xfs_da3_root_join(xfs_da_state_t *state,
                        xfs_da_state_blk_t *root_blk);
 STATIC int xfs_da3_node_toosmall(xfs_da_state_t *state, int *retval);
 STATIC void xfs_da3_node_remove(xfs_da_state_t *state,
                           xfs_da_state_blk_t *drop_blk);
 STATIC void xfs_da3_node_unbalance(xfs_da_state_t *state,
                      xfs_da_state_blk_t *src_node_blk,
                      xfs_da_state_blk_t *dst_node_blk);
 
 /*
  * Utility routines.
  */
 STATIC int  xfs_da3_blk_unlink(xfs_da_state_t *state,
                   xfs_da_state_blk_t *drop_blk,
                   xfs_da_state_blk_t *save_blk);
 
 
 struct kmem_cache   *xfs_da_state_cache;    /* anchor for dir/attr state */
 
 /*
  * Allocate a dir-state structure.
  * We don't put them on the stack since they're large.
  */
 struct xfs_da_state *
 xfs_da_state_alloc(
     struct xfs_da_args  *args)
 {
     struct xfs_da_state *state;
 
     state = kmem_cache_zalloc(xfs_da_state_cache, GFP_NOFS | __GFP_NOFAIL);
     state->args = args;
     state->mp = args->dp->i_mount;
     return state;
 }
 
 /*
  * Kill the altpath contents of a da-state structure.
  */
 STATIC void
 xfs_da_state_kill_altpath(xfs_da_state_t *state)
 {
     int i;
 
     for (i = 0; i < state->altpath.active; i++)
         state->altpath.blk[i].bp = NULL;
     state->altpath.active = 0;
 }
 
 /*
  * Free a da-state structure.
  */
 void
 xfs_da_state_free(xfs_da_state_t *state)
 {
     xfs_da_state_kill_altpath(state);
 #ifdef DEBUG
     memset((char *)state, 0, sizeof(*state));
 #endif /* DEBUG */
     kmem_cache_free(xfs_da_state_cache, state);
 }
 
 void
 xfs_da_state_reset(
     struct xfs_da_state *state,
     struct xfs_da_args  *args)
 {
     xfs_da_state_kill_altpath(state);
     memset(state, 0, sizeof(struct xfs_da_state));
     state->args = args;
     state->mp = state->args->dp->i_mount;
 }
 
 static inline int xfs_dabuf_nfsb(struct xfs_mount *mp, int whichfork)
 {
     if (whichfork == XFS_DATA_FORK)
         return mp->m_dir_geo->fsbcount;
     return mp->m_attr_geo->fsbcount;
 }
 
 void
 xfs_da3_node_hdr_from_disk(
     struct xfs_mount        *mp,
     struct xfs_da3_icnode_hdr   *to,
     struct xfs_da_intnode       *from)
 {
     if (xfs_has_crc(mp)) {
         struct xfs_da3_intnode  *from3 = (struct xfs_da3_intnode *)from;
 
         to->forw = be32_to_cpu(from3->hdr.info.hdr.forw);
         to->back = be32_to_cpu(from3->hdr.info.hdr.back);
         to->magic = be16_to_cpu(from3->hdr.info.hdr.magic);
         to->count = be16_to_cpu(from3->hdr.__count);
         to->level = be16_to_cpu(from3->hdr.__level);
         to->btree = from3->__btree;
         ASSERT(to->magic == XFS_DA3_NODE_MAGIC);
     } else {
         to->forw = be32_to_cpu(from->hdr.info.forw);
         to->back = be32_to_cpu(from->hdr.info.back);
         to->magic = be16_to_cpu(from->hdr.info.magic);
         to->count = be16_to_cpu(from->hdr.__count);
         to->level = be16_to_cpu(from->hdr.__level);
         to->btree = from->__btree;
         ASSERT(to->magic == XFS_DA_NODE_MAGIC);
     }
 }
 
 void
 xfs_da3_node_hdr_to_disk(
     struct xfs_mount        *mp,
     struct xfs_da_intnode       *to,
     struct xfs_da3_icnode_hdr   *from)
 {
     if (xfs_has_crc(mp)) {
         struct xfs_da3_intnode  *to3 = (struct xfs_da3_intnode *)to;
 
         ASSERT(from->magic == XFS_DA3_NODE_MAGIC);
         to3->hdr.info.hdr.forw = cpu_to_be32(from->forw);
         to3->hdr.info.hdr.back = cpu_to_be32(from->back);
         to3->hdr.info.hdr.magic = cpu_to_be16(from->magic);
         to3->hdr.__count = cpu_to_be16(from->count);
         to3->hdr.__level = cpu_to_be16(from->level);
     } else {
         ASSERT(from->magic == XFS_DA_NODE_MAGIC);
         to->hdr.info.forw = cpu_to_be32(from->forw);
         to->hdr.info.back = cpu_to_be32(from->back);
         to->hdr.info.magic = cpu_to_be16(from->magic);
         to->hdr.__count = cpu_to_be16(from->count);
         to->hdr.__level = cpu_to_be16(from->level);
     }
 }
 
 /*
  * Verify an xfs_da3_blkinfo structure. Note that the da3 fields are only
  * accessible on v5 filesystems. This header format is common across da node,
  * attr leaf and dir leaf blocks.
  */
 xfs_failaddr_t
 xfs_da3_blkinfo_verify(
     struct xfs_buf      *bp,
     struct xfs_da3_blkinfo  *hdr3)
 {
     struct xfs_mount    *mp = bp->b_mount;
     struct xfs_da_blkinfo   *hdr = &hdr3->hdr;
 
     if (!xfs_verify_magic16(bp, hdr->magic))
         return __this_address;
 
     if (xfs_has_crc(mp)) {
         if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_meta_uuid))
             return __this_address;
         if (be64_to_cpu(hdr3->blkno) != xfs_buf_daddr(bp))
             return __this_address;
         if (!xfs_log_check_lsn(mp, be64_to_cpu(hdr3->lsn)))
             return __this_address;
     }
 
     return NULL;
 }
 
 static xfs_failaddr_t
 xfs_da3_node_verify(
     struct xfs_buf      *bp)
 {
     struct xfs_mount    *mp = bp->b_mount;
     struct xfs_da_intnode   *hdr = bp->b_addr;
     struct xfs_da3_icnode_hdr ichdr;
     xfs_failaddr_t      fa;
 
     xfs_da3_node_hdr_from_disk(mp, &ichdr, hdr);
 
     fa = xfs_da3_blkinfo_verify(bp, bp->b_addr);
     if (fa)
         return fa;
 
     if (ichdr.level == 0)
         return __this_address;
     if (ichdr.level > XFS_DA_NODE_MAXDEPTH)
         return __this_address;
     if (ichdr.count == 0)
         return __this_address;
 
     /*
      * we don't know if the node is for and attribute or directory tree,
      * so only fail if the count is outside both bounds
      */
     if (ichdr.count > mp->m_dir_geo->node_ents &&
         ichdr.count > mp->m_attr_geo->node_ents)
         return __this_address;
 
     /* XXX: hash order check? */
 
     return NULL;
 }
 
 static void
 xfs_da3_node_write_verify(
     struct xfs_buf  *bp)
 {
     struct xfs_mount    *mp = bp->b_mount;
     struct xfs_buf_log_item *bip = bp->b_log_item;
     struct xfs_da3_node_hdr *hdr3 = bp->b_addr;
     xfs_failaddr_t      fa;
 
     fa = xfs_da3_node_verify(bp);
     if (fa) {
         xfs_verifier_error(bp, -EFSCORRUPTED, fa);
         return;
     }
 
     if (!xfs_has_crc(mp))
         return;
 
     if (bip)
         hdr3->info.lsn = cpu_to_be64(bip->bli_item.li_lsn);
 
     xfs_buf_update_cksum(bp, XFS_DA3_NODE_CRC_OFF);
 }
 
 /*
  * leaf/node format detection on trees is sketchy, so a node read can be done on
  * leaf level blocks when detection identifies the tree as a node format tree
  * incorrectly. In this case, we need to swap the verifier to match the correct
  * format of the block being read.
  */
 static void
 xfs_da3_node_read_verify(
     struct xfs_buf      *bp)
 {
     struct xfs_da_blkinfo   *info = bp->b_addr;
     xfs_failaddr_t      fa;
 
     switch (be16_to_cpu(info->magic)) {
         case XFS_DA3_NODE_MAGIC:
             if (!xfs_buf_verify_cksum(bp, XFS_DA3_NODE_CRC_OFF)) {
                 xfs_verifier_error(bp, -EFSBADCRC,
                         __this_address);
                 break;
             }
             fallthrough;
         case XFS_DA_NODE_MAGIC:
             fa = xfs_da3_node_verify(bp);
             if (fa)
                 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
             return;
         case XFS_ATTR_LEAF_MAGIC:
         case XFS_ATTR3_LEAF_MAGIC:
             bp->b_ops = &xfs_attr3_leaf_buf_ops;
             bp->b_ops->verify_read(bp);
             return;
         case XFS_DIR2_LEAFN_MAGIC:
         case XFS_DIR3_LEAFN_MAGIC:
             bp->b_ops = &xfs_dir3_leafn_buf_ops;
             bp->b_ops->verify_read(bp);
             return;
         default:
             xfs_verifier_error(bp, -EFSCORRUPTED, __this_address);
             break;
     }
 }
 
 /* Verify the structure of a da3 block. */
 static xfs_failaddr_t
 xfs_da3_node_verify_struct(
     struct xfs_buf      *bp)
 {
     struct xfs_da_blkinfo   *info = bp->b_addr;
 
     switch (be16_to_cpu(info->magic)) {
     case XFS_DA3_NODE_MAGIC:
     case XFS_DA_NODE_MAGIC:
         return xfs_da3_node_verify(bp);
     case XFS_ATTR_LEAF_MAGIC:
     case XFS_ATTR3_LEAF_MAGIC:
         bp->b_ops = &xfs_attr3_leaf_buf_ops;
         return bp->b_ops->verify_struct(bp);
     case XFS_DIR2_LEAFN_MAGIC:
     case XFS_DIR3_LEAFN_MAGIC:
         bp->b_ops = &xfs_dir3_leafn_buf_ops;
         return bp->b_ops->verify_struct(bp);
     default:
         return __this_address;
     }
 }
 
 const struct xfs_buf_ops xfs_da3_node_buf_ops = {
     .name = "xfs_da3_node",
     .magic16 = { cpu_to_be16(XFS_DA_NODE_MAGIC),
              cpu_to_be16(XFS_DA3_NODE_MAGIC) },
     .verify_read = xfs_da3_node_read_verify,
     .verify_write = xfs_da3_node_write_verify,
     .verify_struct = xfs_da3_node_verify_struct,
 };
 
 static int
 xfs_da3_node_set_type(
     struct xfs_trans    *tp,
     struct xfs_buf      *bp)
 {
     struct xfs_da_blkinfo   *info = bp->b_addr;
 
     switch (be16_to_cpu(info->magic)) {
     case XFS_DA_NODE_MAGIC:
     case XFS_DA3_NODE_MAGIC:
         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DA_NODE_BUF);
         return 0;
     case XFS_ATTR_LEAF_MAGIC:
     case XFS_ATTR3_LEAF_MAGIC:
         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_ATTR_LEAF_BUF);
         return 0;
     case XFS_DIR2_LEAFN_MAGIC:
     case XFS_DIR3_LEAFN_MAGIC:
         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_LEAFN_BUF);
         return 0;
     default:
         XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, tp->t_mountp,
                 info, sizeof(*info));
         xfs_trans_brelse(tp, bp);
         return -EFSCORRUPTED;
     }
 }
 
 int
 xfs_da3_node_read(
     struct xfs_trans    *tp,
     struct xfs_inode    *dp,
     xfs_dablk_t     bno,
     struct xfs_buf      **bpp,
     int         whichfork)
 {
     int         error;
 
     error = xfs_da_read_buf(tp, dp, bno, 0, bpp, whichfork,
             &xfs_da3_node_buf_ops);
     if (error || !*bpp || !tp)
         return error;
     return xfs_da3_node_set_type(tp, *bpp);
 }
 
 int
 xfs_da3_node_read_mapped(
     struct xfs_trans    *tp,
     struct xfs_inode    *dp,
     xfs_daddr_t     mappedbno,
     struct xfs_buf      **bpp,
     int         whichfork)
 {
     struct xfs_mount    *mp = dp->i_mount;
     int         error;
 
     error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, mappedbno,
             XFS_FSB_TO_BB(mp, xfs_dabuf_nfsb(mp, whichfork)), 0,
             bpp, &xfs_da3_node_buf_ops);
     if (error || !*bpp)
         return error;
 
     if (whichfork == XFS_ATTR_FORK)
         xfs_buf_set_ref(*bpp, XFS_ATTR_BTREE_REF);
     else
         xfs_buf_set_ref(*bpp, XFS_DIR_BTREE_REF);
 
     if (!tp)
         return 0;
     return xfs_da3_node_set_type(tp, *bpp);
 }
 
 /*========================================================================
  * Routines used for growing the Btree.
  *========================================================================*/
 
 /*
  * Create the initial contents of an intermediate node.
  */
 int
 xfs_da3_node_create(
     struct xfs_da_args  *args,
     xfs_dablk_t     blkno,
     int         level,
     struct xfs_buf      **bpp,
     int         whichfork)
 {
     struct xfs_da_intnode   *node;
     struct xfs_trans    *tp = args->trans;
     struct xfs_mount    *mp = tp->t_mountp;
     struct xfs_da3_icnode_hdr ichdr = {0};
     struct xfs_buf      *bp;
     int         error;
     struct xfs_inode    *dp = args->dp;
 
     trace_xfs_da_node_create(args);
     ASSERT(level <= XFS_DA_NODE_MAXDEPTH);
 
     error = xfs_da_get_buf(tp, dp, blkno, &bp, whichfork);
     if (error)
         return error;
     bp->b_ops = &xfs_da3_node_buf_ops;
     xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DA_NODE_BUF);
     node = bp->b_addr;
 
     if (xfs_has_crc(mp)) {
         struct xfs_da3_node_hdr *hdr3 = bp->b_addr;
 
         memset(hdr3, 0, sizeof(struct xfs_da3_node_hdr));
         ichdr.magic = XFS_DA3_NODE_MAGIC;
         hdr3->info.blkno = cpu_to_be64(xfs_buf_daddr(bp));
         hdr3->info.owner = cpu_to_be64(args->dp->i_ino);
         uuid_copy(&hdr3->info.uuid, &mp->m_sb.sb_meta_uuid);
     } else {
         ichdr.magic = XFS_DA_NODE_MAGIC;
     }
     ichdr.level = level;
 
     xfs_da3_node_hdr_to_disk(dp->i_mount, node, &ichdr);
     xfs_trans_log_buf(tp, bp,
         XFS_DA_LOGRANGE(node, &node->hdr, args->geo->node_hdr_size));
 
     *bpp = bp;
     return 0;
 }
 
 /*
  * Split a leaf node, rebalance, then possibly split
  * intermediate nodes, rebalance, etc.
  */
 int                         /* error */
 xfs_da3_split(
     struct xfs_da_state *state)
 {
     struct xfs_da_state_blk *oldblk;
     struct xfs_da_state_blk *newblk;
     struct xfs_da_state_blk *addblk;
     struct xfs_da_intnode   *node;
     int         max;
     int         action = 0;
     int         error;
     int         i;
 
     trace_xfs_da_split(state->args);
 
     if (XFS_TEST_ERROR(false, state->mp, XFS_ERRTAG_DA_LEAF_SPLIT))
         return -EIO;
 
     /*
      * Walk back up the tree splitting/inserting/adjusting as necessary.
      * If we need to insert and there isn't room, split the node, then
      * decide which fragment to insert the new block from below into.
      * Note that we may split the root this way, but we need more fixup.
      */
     max = state->path.active - 1;
     ASSERT((max >= 0) && (max < XFS_DA_NODE_MAXDEPTH));
     ASSERT(state->path.blk[max].magic == XFS_ATTR_LEAF_MAGIC ||
            state->path.blk[max].magic == XFS_DIR2_LEAFN_MAGIC);
 
     addblk = &state->path.blk[max];     /* initial dummy value */
     for (i = max; (i >= 0) && addblk; state->path.active--, i--) {
         oldblk = &state->path.blk[i];
         newblk = &state->altpath.blk[i];
 
         /*
          * If a leaf node then
          *     Allocate a new leaf node, then rebalance across them.
          * else if an intermediate node then
          *     We split on the last layer, must we split the node?
          */
         switch (oldblk->magic) {
         case XFS_ATTR_LEAF_MAGIC:
             error = xfs_attr3_leaf_split(state, oldblk, newblk);
             if ((error != 0) && (error != -ENOSPC)) {
                 return error;   /* GROT: attr is inconsistent */
             }
             if (!error) {
                 addblk = newblk;
                 break;
             }
             /*
              * Entry wouldn't fit, split the leaf again. The new
              * extrablk will be consumed by xfs_da3_node_split if
              * the node is split.
              */
             state->extravalid = 1;
             if (state->inleaf) {
                 state->extraafter = 0;  /* before newblk */
                 trace_xfs_attr_leaf_split_before(state->args);
                 error = xfs_attr3_leaf_split(state, oldblk,
                                 &state->extrablk);
             } else {
                 state->extraafter = 1;  /* after newblk */
                 trace_xfs_attr_leaf_split_after(state->args);
                 error = xfs_attr3_leaf_split(state, newblk,
                                 &state->extrablk);
             }
             if (error)
                 return error;   /* GROT: attr inconsistent */
             addblk = newblk;
             break;
         case XFS_DIR2_LEAFN_MAGIC:
             error = xfs_dir2_leafn_split(state, oldblk, newblk);
             if (error)
                 return error;
             addblk = newblk;
             break;
         case XFS_DA_NODE_MAGIC:
             error = xfs_da3_node_split(state, oldblk, newblk, addblk,
                              max - i, &action);
             addblk->bp = NULL;
             if (error)
                 return error;   /* GROT: dir is inconsistent */
             /*
              * Record the newly split block for the next time thru?
              */
             if (action)
                 addblk = newblk;
             else
                 addblk = NULL;
             break;
         }
 
         /*
          * Update the btree to show the new hashval for this child.
          */
         xfs_da3_fixhashpath(state, &state->path);
     }
     if (!addblk)
         return 0;
 
     /*
      * xfs_da3_node_split() should have consumed any extra blocks we added
      * during a double leaf split in the attr fork. This is guaranteed as
      * we can't be here if the attr fork only has a single leaf block.
      */
     ASSERT(state->extravalid == 0 ||
            state->path.blk[max].magic == XFS_DIR2_LEAFN_MAGIC);
 
     /*
      * Split the root node.
      */
     ASSERT(state->path.active == 0);
     oldblk = &state->path.blk[0];
     error = xfs_da3_root_split(state, oldblk, addblk);
     if (error)
         goto out;
 
     /*
      * Update pointers to the node which used to be block 0 and just got
      * bumped because of the addition of a new root node.  Note that the
      * original block 0 could be at any position in the list of blocks in
      * the tree.
      *
      * Note: the magic numbers and sibling pointers are in the same physical
      * place for both v2 and v3 headers (by design). Hence it doesn't matter
      * which version of the xfs_da_intnode structure we use here as the
      * result will be the same using either structure.
      */
     node = oldblk->bp->b_addr;
     if (node->hdr.info.forw) {
         if (be32_to_cpu(node->hdr.info.forw) != addblk->blkno) {
             xfs_buf_mark_corrupt(oldblk->bp);
             error = -EFSCORRUPTED;
             goto out;
         }
         node = addblk->bp->b_addr;
         node->hdr.info.back = cpu_to_be32(oldblk->blkno);
         xfs_trans_log_buf(state->args->trans, addblk->bp,
                   XFS_DA_LOGRANGE(node, &node->hdr.info,
                   sizeof(node->hdr.info)));
     }
     node = oldblk->bp->b_addr;
     if (node->hdr.info.back) {
         if (be32_to_cpu(node->hdr.info.back) != addblk->blkno) {
             xfs_buf_mark_corrupt(oldblk->bp);
             error = -EFSCORRUPTED;
             goto out;
         }
         node = addblk->bp->b_addr;
         node->hdr.info.forw = cpu_to_be32(oldblk->blkno);
         xfs_trans_log_buf(state->args->trans, addblk->bp,
                   XFS_DA_LOGRANGE(node, &node->hdr.info,
                   sizeof(node->hdr.info)));
     }
 out:
     addblk->bp = NULL;
     return error;
 }
 
 /*
  * Split the root.  We have to create a new root and point to the two
  * parts (the split old root) that we just created.  Copy block zero to
  * the EOF, extending the inode in process.
  */
 STATIC int                      /* error */
 xfs_da3_root_split(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *blk1,
     struct xfs_da_state_blk *blk2)
 {
     struct xfs_da_intnode   *node;
     struct xfs_da_intnode   *oldroot;
     struct xfs_da_node_entry *btree;
     struct xfs_da3_icnode_hdr nodehdr;
     struct xfs_da_args  *args;
     struct xfs_buf      *bp;
     struct xfs_inode    *dp;
     struct xfs_trans    *tp;
     struct xfs_dir2_leaf    *leaf;
     xfs_dablk_t     blkno;
     int         level;
     int         error;
     int         size;
 
     trace_xfs_da_root_split(state->args);
 
     /*
      * Copy the existing (incorrect) block from the root node position
      * to a free space somewhere.
      */
     args = state->args;
     error = xfs_da_grow_inode(args, &blkno);
     if (error)
         return error;
 
     dp = args->dp;
     tp = args->trans;
     error = xfs_da_get_buf(tp, dp, blkno, &bp, args->whichfork);
     if (error)
         return error;
     node = bp->b_addr;
     oldroot = blk1->bp->b_addr;
     if (oldroot->hdr.info.magic == cpu_to_be16(XFS_DA_NODE_MAGIC) ||
         oldroot->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC)) {
         struct xfs_da3_icnode_hdr icnodehdr;
 
         xfs_da3_node_hdr_from_disk(dp->i_mount, &icnodehdr, oldroot);
         btree = icnodehdr.btree;
         size = (int)((char *)&btree[icnodehdr.count] - (char *)oldroot);
         level = icnodehdr.level;
 
         /*
          * we are about to copy oldroot to bp, so set up the type
          * of bp while we know exactly what it will be.
          */
         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DA_NODE_BUF);
     } else {
         struct xfs_dir3_icleaf_hdr leafhdr;
 
         leaf = (xfs_dir2_leaf_t *)oldroot;
         xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &leafhdr, leaf);
 
         ASSERT(leafhdr.magic == XFS_DIR2_LEAFN_MAGIC ||
                leafhdr.magic == XFS_DIR3_LEAFN_MAGIC);
         size = (int)((char *)&leafhdr.ents[leafhdr.count] -
             (char *)leaf);
         level = 0;
 
         /*
          * we are about to copy oldroot to bp, so set up the type
          * of bp while we know exactly what it will be.
          */
         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_LEAFN_BUF);
     }
 
     /*
      * we can copy most of the information in the node from one block to
      * another, but for CRC enabled headers we have to make sure that the
      * block specific identifiers are kept intact. We update the buffer
      * directly for this.
      */
     memcpy(node, oldroot, size);
     if (oldroot->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC) ||
         oldroot->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
         struct xfs_da3_intnode *node3 = (struct xfs_da3_intnode *)node;
 
         node3->hdr.info.blkno = cpu_to_be64(xfs_buf_daddr(bp));
     }
     xfs_trans_log_buf(tp, bp, 0, size - 1);
 
     bp->b_ops = blk1->bp->b_ops;
     xfs_trans_buf_copy_type(bp, blk1->bp);
     blk1->bp = bp;
     blk1->blkno = blkno;
 
     /*
      * Set up the new root node.
      */
     error = xfs_da3_node_create(args,
         (args->whichfork == XFS_DATA_FORK) ? args->geo->leafblk : 0,
         level + 1, &bp, args->whichfork);
     if (error)
         return error;
 
     node = bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
     btree = nodehdr.btree;
     btree[0].hashval = cpu_to_be32(blk1->hashval);
     btree[0].before = cpu_to_be32(blk1->blkno);
     btree[1].hashval = cpu_to_be32(blk2->hashval);
     btree[1].before = cpu_to_be32(blk2->blkno);
     nodehdr.count = 2;
     xfs_da3_node_hdr_to_disk(dp->i_mount, node, &nodehdr);
 
 #ifdef DEBUG
     if (oldroot->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
         oldroot->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
         ASSERT(blk1->blkno >= args->geo->leafblk &&
                blk1->blkno < args->geo->freeblk);
         ASSERT(blk2->blkno >= args->geo->leafblk &&
                blk2->blkno < args->geo->freeblk);
     }
 #endif
 
     /* Header is already logged by xfs_da_node_create */
     xfs_trans_log_buf(tp, bp,
         XFS_DA_LOGRANGE(node, btree, sizeof(xfs_da_node_entry_t) * 2));
 
     return 0;
 }
 
 /*
  * Split the node, rebalance, then add the new entry.
  */
 STATIC int                      /* error */
 xfs_da3_node_split(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *oldblk,
     struct xfs_da_state_blk *newblk,
     struct xfs_da_state_blk *addblk,
     int         treelevel,
     int         *result)
 {
     struct xfs_da_intnode   *node;
     struct xfs_da3_icnode_hdr nodehdr;
     xfs_dablk_t     blkno;
     int         newcount;
     int         error;
     int         useextra;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_node_split(state->args);
 
     node = oldblk->bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
 
     /*
      * With V2 dirs the extra block is data or freespace.
      */
     useextra = state->extravalid && state->args->whichfork == XFS_ATTR_FORK;
     newcount = 1 + useextra;
     /*
      * Do we have to split the node?
      */
     if (nodehdr.count + newcount > state->args->geo->node_ents) {
         /*
          * Allocate a new node, add to the doubly linked chain of
          * nodes, then move some of our excess entries into it.
          */
         error = xfs_da_grow_inode(state->args, &blkno);
         if (error)
             return error;   /* GROT: dir is inconsistent */
 
         error = xfs_da3_node_create(state->args, blkno, treelevel,
                        &newblk->bp, state->args->whichfork);
         if (error)
             return error;   /* GROT: dir is inconsistent */
         newblk->blkno = blkno;
         newblk->magic = XFS_DA_NODE_MAGIC;
         xfs_da3_node_rebalance(state, oldblk, newblk);
         error = xfs_da3_blk_link(state, oldblk, newblk);
         if (error)
             return error;
         *result = 1;
     } else {
         *result = 0;
     }
 
     /*
      * Insert the new entry(s) into the correct block
      * (updating last hashval in the process).
      *
      * xfs_da3_node_add() inserts BEFORE the given index,
      * and as a result of using node_lookup_int() we always
      * point to a valid entry (not after one), but a split
      * operation always results in a new block whose hashvals
      * FOLLOW the current block.
      *
      * If we had double-split op below us, then add the extra block too.
      */
     node = oldblk->bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
     if (oldblk->index <= nodehdr.count) {
         oldblk->index++;
         xfs_da3_node_add(state, oldblk, addblk);
         if (useextra) {
             if (state->extraafter)
                 oldblk->index++;
             xfs_da3_node_add(state, oldblk, &state->extrablk);
             state->extravalid = 0;
         }
     } else {
         newblk->index++;
         xfs_da3_node_add(state, newblk, addblk);
         if (useextra) {
             if (state->extraafter)
                 newblk->index++;
             xfs_da3_node_add(state, newblk, &state->extrablk);
             state->extravalid = 0;
         }
     }
 
     return 0;
 }
 
 /*
  * Balance the btree elements between two intermediate nodes,
  * usually one full and one empty.
  *
  * NOTE: if blk2 is empty, then it will get the upper half of blk1.
  */
 STATIC void
 xfs_da3_node_rebalance(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *blk1,
     struct xfs_da_state_blk *blk2)
 {
     struct xfs_da_intnode   *node1;
     struct xfs_da_intnode   *node2;
     struct xfs_da_node_entry *btree1;
     struct xfs_da_node_entry *btree2;
     struct xfs_da_node_entry *btree_s;
     struct xfs_da_node_entry *btree_d;
     struct xfs_da3_icnode_hdr nodehdr1;
     struct xfs_da3_icnode_hdr nodehdr2;
     struct xfs_trans    *tp;
     int         count;
     int         tmp;
     int         swap = 0;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_node_rebalance(state->args);
 
     node1 = blk1->bp->b_addr;
     node2 = blk2->bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr1, node1);
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr2, node2);
     btree1 = nodehdr1.btree;
     btree2 = nodehdr2.btree;
 
     /*
      * Figure out how many entries need to move, and in which direction.
      * Swap the nodes around if that makes it simpler.
      */
     if (nodehdr1.count > 0 && nodehdr2.count > 0 &&
         ((be32_to_cpu(btree2[0].hashval) < be32_to_cpu(btree1[0].hashval)) ||
          (be32_to_cpu(btree2[nodehdr2.count - 1].hashval) <
             be32_to_cpu(btree1[nodehdr1.count - 1].hashval)))) {
         swap(node1, node2);
         xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr1, node1);
         xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr2, node2);
         btree1 = nodehdr1.btree;
         btree2 = nodehdr2.btree;
         swap = 1;
     }
 
     count = (nodehdr1.count - nodehdr2.count) / 2;
     if (count == 0)
         return;
     tp = state->args->trans;
     /*
      * Two cases: high-to-low and low-to-high.
      */
     if (count > 0) {
         /*
          * Move elements in node2 up to make a hole.
          */
         tmp = nodehdr2.count;
         if (tmp > 0) {
             tmp *= (uint)sizeof(xfs_da_node_entry_t);
             btree_s = &btree2[0];
             btree_d = &btree2[count];
             memmove(btree_d, btree_s, tmp);
         }
 
         /*
          * Move the req'd B-tree elements from high in node1 to
          * low in node2.
          */
         nodehdr2.count += count;
         tmp = count * (uint)sizeof(xfs_da_node_entry_t);
         btree_s = &btree1[nodehdr1.count - count];
         btree_d = &btree2[0];
         memcpy(btree_d, btree_s, tmp);
         nodehdr1.count -= count;
     } else {
         /*
          * Move the req'd B-tree elements from low in node2 to
          * high in node1.
          */
         count = -count;
         tmp = count * (uint)sizeof(xfs_da_node_entry_t);
         btree_s = &btree2[0];
         btree_d = &btree1[nodehdr1.count];
         memcpy(btree_d, btree_s, tmp);
         nodehdr1.count += count;
 
         xfs_trans_log_buf(tp, blk1->bp,
             XFS_DA_LOGRANGE(node1, btree_d, tmp));
 
         /*
          * Move elements in node2 down to fill the hole.
          */
         tmp  = nodehdr2.count - count;
         tmp *= (uint)sizeof(xfs_da_node_entry_t);
         btree_s = &btree2[count];
         btree_d = &btree2[0];
         memmove(btree_d, btree_s, tmp);
         nodehdr2.count -= count;
     }
 
     /*
      * Log header of node 1 and all current bits of node 2.
      */
     xfs_da3_node_hdr_to_disk(dp->i_mount, node1, &nodehdr1);
     xfs_trans_log_buf(tp, blk1->bp,
         XFS_DA_LOGRANGE(node1, &node1->hdr,
                 state->args->geo->node_hdr_size));
 
     xfs_da3_node_hdr_to_disk(dp->i_mount, node2, &nodehdr2);
     xfs_trans_log_buf(tp, blk2->bp,
         XFS_DA_LOGRANGE(node2, &node2->hdr,
                 state->args->geo->node_hdr_size +
                 (sizeof(btree2[0]) * nodehdr2.count)));
 
     /*
      * Record the last hashval from each block for upward propagation.
      * (note: don't use the swapped node pointers)
      */
     if (swap) {
         node1 = blk1->bp->b_addr;
         node2 = blk2->bp->b_addr;
         xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr1, node1);
         xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr2, node2);
         btree1 = nodehdr1.btree;
         btree2 = nodehdr2.btree;
     }
     blk1->hashval = be32_to_cpu(btree1[nodehdr1.count - 1].hashval);
     blk2->hashval = be32_to_cpu(btree2[nodehdr2.count - 1].hashval);
 
     /*
      * Adjust the expected index for insertion.
      */
     if (blk1->index >= nodehdr1.count) {
         blk2->index = blk1->index - nodehdr1.count;
         blk1->index = nodehdr1.count + 1;   /* make it invalid */
     }
 }
 
 /*
  * Add a new entry to an intermediate node.
  */
 STATIC void
 xfs_da3_node_add(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *oldblk,
     struct xfs_da_state_blk *newblk)
 {
     struct xfs_da_intnode   *node;
     struct xfs_da3_icnode_hdr nodehdr;
     struct xfs_da_node_entry *btree;
     int         tmp;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_node_add(state->args);
 
     node = oldblk->bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
     btree = nodehdr.btree;
 
     ASSERT(oldblk->index >= 0 && oldblk->index <= nodehdr.count);
     ASSERT(newblk->blkno != 0);
     if (state->args->whichfork == XFS_DATA_FORK)
         ASSERT(newblk->blkno >= state->args->geo->leafblk &&
                newblk->blkno < state->args->geo->freeblk);
 
     /*
      * We may need to make some room before we insert the new node.
      */
     tmp = 0;
     if (oldblk->index < nodehdr.count) {
         tmp = (nodehdr.count - oldblk->index) * (uint)sizeof(*btree);
         memmove(&btree[oldblk->index + 1], &btree[oldblk->index], tmp);
     }
     btree[oldblk->index].hashval = cpu_to_be32(newblk->hashval);
     btree[oldblk->index].before = cpu_to_be32(newblk->blkno);
     xfs_trans_log_buf(state->args->trans, oldblk->bp,
         XFS_DA_LOGRANGE(node, &btree[oldblk->index],
                 tmp + sizeof(*btree)));
 
     nodehdr.count += 1;
     xfs_da3_node_hdr_to_disk(dp->i_mount, node, &nodehdr);
     xfs_trans_log_buf(state->args->trans, oldblk->bp,
         XFS_DA_LOGRANGE(node, &node->hdr,
                 state->args->geo->node_hdr_size));
 
     /*
      * Copy the last hash value from the oldblk to propagate upwards.
      */
     oldblk->hashval = be32_to_cpu(btree[nodehdr.count - 1].hashval);
 }
 
 /*========================================================================
  * Routines used for shrinking the Btree.
  *========================================================================*/
 
 /*
  * Deallocate an empty leaf node, remove it from its parent,
  * possibly deallocating that block, etc...
  */
 int
 xfs_da3_join(
     struct xfs_da_state *state)
 {
     struct xfs_da_state_blk *drop_blk;
     struct xfs_da_state_blk *save_blk;
     int         action = 0;
     int         error;
 
     trace_xfs_da_join(state->args);
 
     drop_blk = &state->path.blk[ state->path.active-1 ];
     save_blk = &state->altpath.blk[ state->path.active-1 ];
     ASSERT(state->path.blk[0].magic == XFS_DA_NODE_MAGIC);
     ASSERT(drop_blk->magic == XFS_ATTR_LEAF_MAGIC ||
            drop_blk->magic == XFS_DIR2_LEAFN_MAGIC);
 
     /*
      * Walk back up the tree joining/deallocating as necessary.
      * When we stop dropping blocks, break out.
      */
     for (  ; state->path.active >= 2; drop_blk--, save_blk--,
          state->path.active--) {
         /*
          * See if we can combine the block with a neighbor.
          *   (action == 0) => no options, just leave
          *   (action == 1) => coalesce, then unlink
          *   (action == 2) => block empty, unlink it
          */
         switch (drop_blk->magic) {
         case XFS_ATTR_LEAF_MAGIC:
             error = xfs_attr3_leaf_toosmall(state, &action);
             if (error)
                 return error;
             if (action == 0)
                 return 0;
             xfs_attr3_leaf_unbalance(state, drop_blk, save_blk);
             break;
         case XFS_DIR2_LEAFN_MAGIC:
             error = xfs_dir2_leafn_toosmall(state, &action);
             if (error)
                 return error;
             if (action == 0)
                 return 0;
             xfs_dir2_leafn_unbalance(state, drop_blk, save_blk);
             break;
         case XFS_DA_NODE_MAGIC:
             /*
              * Remove the offending node, fixup hashvals,
              * check for a toosmall neighbor.
              */
             xfs_da3_node_remove(state, drop_blk);
             xfs_da3_fixhashpath(state, &state->path);
             error = xfs_da3_node_toosmall(state, &action);
             if (error)
                 return error;
             if (action == 0)
                 return 0;
             xfs_da3_node_unbalance(state, drop_blk, save_blk);
             break;
         }
         xfs_da3_fixhashpath(state, &state->altpath);
         error = xfs_da3_blk_unlink(state, drop_blk, save_blk);
         xfs_da_state_kill_altpath(state);
         if (error)
             return error;
         error = xfs_da_shrink_inode(state->args, drop_blk->blkno,
                              drop_blk->bp);
         drop_blk->bp = NULL;
         if (error)
             return error;
     }
     /*
      * We joined all the way to the top.  If it turns out that
      * we only have one entry in the root, make the child block
      * the new root.
      */
     xfs_da3_node_remove(state, drop_blk);
     xfs_da3_fixhashpath(state, &state->path);
     error = xfs_da3_root_join(state, &state->path.blk[0]);
     return error;
 }
 
 #ifdef  DEBUG
 static void
 xfs_da_blkinfo_onlychild_validate(struct xfs_da_blkinfo *blkinfo, __u16 level)
 {
     __be16  magic = blkinfo->magic;
 
     if (level == 1) {
         ASSERT(magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
                magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC) ||
                magic == cpu_to_be16(XFS_ATTR_LEAF_MAGIC) ||
                magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC));
     } else {
         ASSERT(magic == cpu_to_be16(XFS_DA_NODE_MAGIC) ||
                magic == cpu_to_be16(XFS_DA3_NODE_MAGIC));
     }
     ASSERT(!blkinfo->forw);
     ASSERT(!blkinfo->back);
 }
 #else   /* !DEBUG */
 #define xfs_da_blkinfo_onlychild_validate(blkinfo, level)
 #endif  /* !DEBUG */
 
 /*
  * We have only one entry in the root.  Copy the only remaining child of
  * the old root to block 0 as the new root node.
  */
 STATIC int
 xfs_da3_root_join(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *root_blk)
 {
     struct xfs_da_intnode   *oldroot;
     struct xfs_da_args  *args;
     xfs_dablk_t     child;
     struct xfs_buf      *bp;
     struct xfs_da3_icnode_hdr oldroothdr;
     int         error;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_root_join(state->args);
 
     ASSERT(root_blk->magic == XFS_DA_NODE_MAGIC);
 
     args = state->args;
     oldroot = root_blk->bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &oldroothdr, oldroot);
     ASSERT(oldroothdr.forw == 0);
     ASSERT(oldroothdr.back == 0);
 
     /*
      * If the root has more than one child, then don't do anything.
      */
     if (oldroothdr.count > 1)
         return 0;
 
     /*
      * Read in the (only) child block, then copy those bytes into
      * the root block's buffer and free the original child block.
      */
     child = be32_to_cpu(oldroothdr.btree[0].before);
     ASSERT(child != 0);
     error = xfs_da3_node_read(args->trans, dp, child, &bp, args->whichfork);
     if (error)
         return error;
     xfs_da_blkinfo_onlychild_validate(bp->b_addr, oldroothdr.level);
 
     /*
      * This could be copying a leaf back into the root block in the case of
      * there only being a single leaf block left in the tree. Hence we have
      * to update the b_ops pointer as well to match the buffer type change
      * that could occur. For dir3 blocks we also need to update the block
      * number in the buffer header.
      */
     memcpy(root_blk->bp->b_addr, bp->b_addr, args->geo->blksize);
     root_blk->bp->b_ops = bp->b_ops;
     xfs_trans_buf_copy_type(root_blk->bp, bp);
     if (oldroothdr.magic == XFS_DA3_NODE_MAGIC) {
         struct xfs_da3_blkinfo *da3 = root_blk->bp->b_addr;
         da3->blkno = cpu_to_be64(xfs_buf_daddr(root_blk->bp));
     }
     xfs_trans_log_buf(args->trans, root_blk->bp, 0,
               args->geo->blksize - 1);
     error = xfs_da_shrink_inode(args, child, bp);
     return error;
 }
 
 /*
  * Check a node block and its neighbors to see if the block should be
  * collapsed into one or the other neighbor.  Always keep the block
  * with the smaller block number.
  * If the current block is over 50% full, don't try to join it, return 0.
  * If the block is empty, fill in the state structure and return 2.
  * If it can be collapsed, fill in the state structure and return 1.
  * If nothing can be done, return 0.
  */
 STATIC int
 xfs_da3_node_toosmall(
     struct xfs_da_state *state,
     int         *action)
 {
     struct xfs_da_intnode   *node;
     struct xfs_da_state_blk *blk;
     struct xfs_da_blkinfo   *info;
     xfs_dablk_t     blkno;
     struct xfs_buf      *bp;
     struct xfs_da3_icnode_hdr nodehdr;
     int         count;
     int         forward;
     int         error;
     int         retval;
     int         i;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_node_toosmall(state->args);
 
     /*
      * Check for the degenerate case of the block being over 50% full.
      * If so, it's not worth even looking to see if we might be able
      * to coalesce with a sibling.
      */
     blk = &state->path.blk[ state->path.active-1 ];
     info = blk->bp->b_addr;
     node = (xfs_da_intnode_t *)info;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
     if (nodehdr.count > (state->args->geo->node_ents >> 1)) {
         *action = 0;    /* blk over 50%, don't try to join */
         return 0;   /* blk over 50%, don't try to join */
     }
 
     /*
      * Check for the degenerate case of the block being empty.
      * If the block is empty, we'll simply delete it, no need to
      * coalesce it with a sibling block.  We choose (arbitrarily)
      * to merge with the forward block unless it is NULL.
      */
     if (nodehdr.count == 0) {
         /*
          * Make altpath point to the block we want to keep and
          * path point to the block we want to drop (this one).
          */
         forward = (info->forw != 0);
         memcpy(&state->altpath, &state->path, sizeof(state->path));
         error = xfs_da3_path_shift(state, &state->altpath, forward,
                          0, &retval);
         if (error)
             return error;
         if (retval) {
             *action = 0;
         } else {
             *action = 2;
         }
         return 0;
     }
 
     /*
      * Examine each sibling block to see if we can coalesce with
      * at least 25% free space to spare.  We need to figure out
      * whether to merge with the forward or the backward block.
      * We prefer coalescing with the lower numbered sibling so as
      * to shrink a directory over time.
      */
     count  = state->args->geo->node_ents;
     count -= state->args->geo->node_ents >> 2;
     count -= nodehdr.count;
 
     /* start with smaller blk num */
     forward = nodehdr.forw < nodehdr.back;
     for (i = 0; i < 2; forward = !forward, i++) {
         struct xfs_da3_icnode_hdr thdr;
         if (forward)
             blkno = nodehdr.forw;
         else
             blkno = nodehdr.back;
         if (blkno == 0)
             continue;
         error = xfs_da3_node_read(state->args->trans, dp, blkno, &bp,
                 state->args->whichfork);
         if (error)
             return error;
 
         node = bp->b_addr;
         xfs_da3_node_hdr_from_disk(dp->i_mount, &thdr, node);
         xfs_trans_brelse(state->args->trans, bp);
 
         if (count - thdr.count >= 0)
             break;  /* fits with at least 25% to spare */
     }
     if (i >= 2) {
         *action = 0;
         return 0;
     }
 
     /*
      * Make altpath point to the block we want to keep (the lower
      * numbered block) and path point to the block we want to drop.
      */
     memcpy(&state->altpath, &state->path, sizeof(state->path));
     if (blkno < blk->blkno) {
         error = xfs_da3_path_shift(state, &state->altpath, forward,
                          0, &retval);
     } else {
         error = xfs_da3_path_shift(state, &state->path, forward,
                          0, &retval);
     }
     if (error)
         return error;
     if (retval) {
         *action = 0;
         return 0;
     }
     *action = 1;
     return 0;
 }
 
 /*
  * Pick up the last hashvalue from an intermediate node.
  */
 STATIC uint
 xfs_da3_node_lasthash(
     struct xfs_inode    *dp,
     struct xfs_buf      *bp,
     int         *count)
 {
     struct xfs_da3_icnode_hdr nodehdr;
 
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, bp->b_addr);
     if (count)
         *count = nodehdr.count;
     if (!nodehdr.count)
         return 0;
     return be32_to_cpu(nodehdr.btree[nodehdr.count - 1].hashval);
 }
 
 /*
  * Walk back up the tree adjusting hash values as necessary,
  * when we stop making changes, return.
  */
 void
 xfs_da3_fixhashpath(
     struct xfs_da_state *state,
     struct xfs_da_state_path *path)
 {
     struct xfs_da_state_blk *blk;
     struct xfs_da_intnode   *node;
     struct xfs_da_node_entry *btree;
     xfs_dahash_t        lasthash=0;
     int         level;
     int         count;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_fixhashpath(state->args);
 
     level = path->active-1;
     blk = &path->blk[ level ];
     switch (blk->magic) {
     case XFS_ATTR_LEAF_MAGIC:
         lasthash = xfs_attr_leaf_lasthash(blk->bp, &count);
         if (count == 0)
             return;
         break;
     case XFS_DIR2_LEAFN_MAGIC:
         lasthash = xfs_dir2_leaf_lasthash(dp, blk->bp, &count);
         if (count == 0)
             return;
         break;
     case XFS_DA_NODE_MAGIC:
         lasthash = xfs_da3_node_lasthash(dp, blk->bp, &count);
         if (count == 0)
             return;
         break;
     }
     for (blk--, level--; level >= 0; blk--, level--) {
         struct xfs_da3_icnode_hdr nodehdr;
 
         node = blk->bp->b_addr;
         xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
         btree = nodehdr.btree;
         if (be32_to_cpu(btree[blk->index].hashval) == lasthash)
             break;
         blk->hashval = lasthash;
         btree[blk->index].hashval = cpu_to_be32(lasthash);
         xfs_trans_log_buf(state->args->trans, blk->bp,
                   XFS_DA_LOGRANGE(node, &btree[blk->index],
                           sizeof(*btree)));
 
         lasthash = be32_to_cpu(btree[nodehdr.count - 1].hashval);
     }
 }
 
 /*
  * Remove an entry from an intermediate node.
  */
 STATIC void
 xfs_da3_node_remove(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *drop_blk)
 {
     struct xfs_da_intnode   *node;
     struct xfs_da3_icnode_hdr nodehdr;
     struct xfs_da_node_entry *btree;
     int         index;
     int         tmp;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_node_remove(state->args);
 
     node = drop_blk->bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
     ASSERT(drop_blk->index < nodehdr.count);
     ASSERT(drop_blk->index >= 0);
 
     /*
      * Copy over the offending entry, or just zero it out.
      */
     index = drop_blk->index;
     btree = nodehdr.btree;
     if (index < nodehdr.count - 1) {
         tmp  = nodehdr.count - index - 1;
         tmp *= (uint)sizeof(xfs_da_node_entry_t);
         memmove(&btree[index], &btree[index + 1], tmp);
         xfs_trans_log_buf(state->args->trans, drop_blk->bp,
             XFS_DA_LOGRANGE(node, &btree[index], tmp));
         index = nodehdr.count - 1;
     }
     memset(&btree[index], 0, sizeof(xfs_da_node_entry_t));
     xfs_trans_log_buf(state->args->trans, drop_blk->bp,
         XFS_DA_LOGRANGE(node, &btree[index], sizeof(btree[index])));
     nodehdr.count -= 1;
     xfs_da3_node_hdr_to_disk(dp->i_mount, node, &nodehdr);
     xfs_trans_log_buf(state->args->trans, drop_blk->bp,
         XFS_DA_LOGRANGE(node, &node->hdr, state->args->geo->node_hdr_size));
 
     /*
      * Copy the last hash value from the block to propagate upwards.
      */
     drop_blk->hashval = be32_to_cpu(btree[index - 1].hashval);
 }
 
 /*
  * Unbalance the elements between two intermediate nodes,
  * move all Btree elements from one node into another.
  */
 STATIC void
 xfs_da3_node_unbalance(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *drop_blk,
     struct xfs_da_state_blk *save_blk)
 {
     struct xfs_da_intnode   *drop_node;
     struct xfs_da_intnode   *save_node;
     struct xfs_da_node_entry *drop_btree;
     struct xfs_da_node_entry *save_btree;
     struct xfs_da3_icnode_hdr drop_hdr;
     struct xfs_da3_icnode_hdr save_hdr;
     struct xfs_trans    *tp;
     int         sindex;
     int         tmp;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_node_unbalance(state->args);
 
     drop_node = drop_blk->bp->b_addr;
     save_node = save_blk->bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &drop_hdr, drop_node);
     xfs_da3_node_hdr_from_disk(dp->i_mount, &save_hdr, save_node);
     drop_btree = drop_hdr.btree;
     save_btree = save_hdr.btree;
     tp = state->args->trans;
 
     /*
      * If the dying block has lower hashvals, then move all the
      * elements in the remaining block up to make a hole.
      */
     if ((be32_to_cpu(drop_btree[0].hashval) <
             be32_to_cpu(save_btree[0].hashval)) ||
         (be32_to_cpu(drop_btree[drop_hdr.count - 1].hashval) <
             be32_to_cpu(save_btree[save_hdr.count - 1].hashval))) {
         /* XXX: check this - is memmove dst correct? */
         tmp = save_hdr.count * sizeof(xfs_da_node_entry_t);
         memmove(&save_btree[drop_hdr.count], &save_btree[0], tmp);
 
         sindex = 0;
         xfs_trans_log_buf(tp, save_blk->bp,
             XFS_DA_LOGRANGE(save_node, &save_btree[0],
                 (save_hdr.count + drop_hdr.count) *
                         sizeof(xfs_da_node_entry_t)));
     } else {
         sindex = save_hdr.count;
         xfs_trans_log_buf(tp, save_blk->bp,
             XFS_DA_LOGRANGE(save_node, &save_btree[sindex],
                 drop_hdr.count * sizeof(xfs_da_node_entry_t)));
     }
 
     /*
      * Move all the B-tree elements from drop_blk to save_blk.
      */
     tmp = drop_hdr.count * (uint)sizeof(xfs_da_node_entry_t);
     memcpy(&save_btree[sindex], &drop_btree[0], tmp);
     save_hdr.count += drop_hdr.count;
 
     xfs_da3_node_hdr_to_disk(dp->i_mount, save_node, &save_hdr);
     xfs_trans_log_buf(tp, save_blk->bp,
         XFS_DA_LOGRANGE(save_node, &save_node->hdr,
                 state->args->geo->node_hdr_size));
 
     /*
      * Save the last hashval in the remaining block for upward propagation.
      */
     save_blk->hashval = be32_to_cpu(save_btree[save_hdr.count - 1].hashval);
 }
 
 /*========================================================================
  * Routines used for finding things in the Btree.
  *========================================================================*/
 
 /*
  * Walk down the Btree looking for a particular filename, filling
  * in the state structure as we go.
  *
  * We will set the state structure to point to each of the elements
  * in each of the nodes where either the hashval is or should be.
  *
  * We support duplicate hashval's so for each entry in the current
  * node that could contain the desired hashval, descend.  This is a
  * pruned depth-first tree search.
  */
 int                         /* error */
 xfs_da3_node_lookup_int(
     struct xfs_da_state *state,
     int         *result)
 {
     struct xfs_da_state_blk *blk;
     struct xfs_da_blkinfo   *curr;
     struct xfs_da_intnode   *node;
     struct xfs_da_node_entry *btree;
     struct xfs_da3_icnode_hdr nodehdr;
     struct xfs_da_args  *args;
     xfs_dablk_t     blkno;
     xfs_dahash_t        hashval;
     xfs_dahash_t        btreehashval;
     int         probe;
     int         span;
     int         max;
     int         error;
     int         retval;
     unsigned int        expected_level = 0;
     uint16_t        magic;
     struct xfs_inode    *dp = state->args->dp;
 
     args = state->args;
 
     /*
      * Descend thru the B-tree searching each level for the right
      * node to use, until the right hashval is found.
      */
     blkno = args->geo->leafblk;
     for (blk = &state->path.blk[0], state->path.active = 1;
              state->path.active <= XFS_DA_NODE_MAXDEPTH;
              blk++, state->path.active++) {
         /*
          * Read the next node down in the tree.
          */
         blk->blkno = blkno;
         error = xfs_da3_node_read(args->trans, args->dp, blkno,
                     &blk->bp, args->whichfork);
         if (error) {
             blk->blkno = 0;
             state->path.active--;
             return error;
         }
         curr = blk->bp->b_addr;
         magic = be16_to_cpu(curr->magic);
 
         if (magic == XFS_ATTR_LEAF_MAGIC ||
             magic == XFS_ATTR3_LEAF_MAGIC) {
             blk->magic = XFS_ATTR_LEAF_MAGIC;
             blk->hashval = xfs_attr_leaf_lasthash(blk->bp, NULL);
             break;
         }
 
         if (magic == XFS_DIR2_LEAFN_MAGIC ||
             magic == XFS_DIR3_LEAFN_MAGIC) {
             blk->magic = XFS_DIR2_LEAFN_MAGIC;
             blk->hashval = xfs_dir2_leaf_lasthash(args->dp,
                                   blk->bp, NULL);
             break;
         }
 
         if (magic != XFS_DA_NODE_MAGIC && magic != XFS_DA3_NODE_MAGIC) {
             xfs_buf_mark_corrupt(blk->bp);
             return -EFSCORRUPTED;
         }
 
         blk->magic = XFS_DA_NODE_MAGIC;
 
         /*
          * Search an intermediate node for a match.
          */
         node = blk->bp->b_addr;
         xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr, node);
         btree = nodehdr.btree;
 
         /* Tree taller than we can handle; bail out! */
         if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH) {
             xfs_buf_mark_corrupt(blk->bp);
             return -EFSCORRUPTED;
         }
 
         /* Check the level from the root. */
         if (blkno == args->geo->leafblk)
             expected_level = nodehdr.level - 1;
         else if (expected_level != nodehdr.level) {
             xfs_buf_mark_corrupt(blk->bp);
             return -EFSCORRUPTED;
         } else
             expected_level--;
 
         max = nodehdr.count;
         blk->hashval = be32_to_cpu(btree[max - 1].hashval);
 
         /*
          * Binary search.  (note: small blocks will skip loop)
          */
         probe = span = max / 2;
         hashval = args->hashval;
         while (span > 4) {
             span /= 2;
             btreehashval = be32_to_cpu(btree[probe].hashval);
             if (btreehashval < hashval)
                 probe += span;
             else if (btreehashval > hashval)
                 probe -= span;
             else
                 break;
         }
         ASSERT((probe >= 0) && (probe < max));
         ASSERT((span <= 4) ||
             (be32_to_cpu(btree[probe].hashval) == hashval));
 
         /*
          * Since we may have duplicate hashval's, find the first
          * matching hashval in the node.
          */
         while (probe > 0 &&
                be32_to_cpu(btree[probe].hashval) >= hashval) {
             probe--;
         }
         while (probe < max &&
                be32_to_cpu(btree[probe].hashval) < hashval) {
             probe++;
         }
 
         /*
          * Pick the right block to descend on.
          */
         if (probe == max) {
             blk->index = max - 1;
             blkno = be32_to_cpu(btree[max - 1].before);
         } else {
             blk->index = probe;
             blkno = be32_to_cpu(btree[probe].before);
         }
 
         /* We can't point back to the root. */
         if (XFS_IS_CORRUPT(dp->i_mount, blkno == args->geo->leafblk))
             return -EFSCORRUPTED;
     }
 
     if (XFS_IS_CORRUPT(dp->i_mount, expected_level != 0))
         return -EFSCORRUPTED;
 
     /*
      * A leaf block that ends in the hashval that we are interested in
      * (final hashval == search hashval) means that the next block may
      * contain more entries with the same hashval, shift upward to the
      * next leaf and keep searching.
      */
     for (;;) {
         if (blk->magic == XFS_DIR2_LEAFN_MAGIC) {
             retval = xfs_dir2_leafn_lookup_int(blk->bp, args,
                             &blk->index, state);
         } else if (blk->magic == XFS_ATTR_LEAF_MAGIC) {
             retval = xfs_attr3_leaf_lookup_int(blk->bp, args);
             blk->index = args->index;
             args->blkno = blk->blkno;
         } else {
             ASSERT(0);
             return -EFSCORRUPTED;
         }
         if (((retval == -ENOENT) || (retval == -ENOATTR)) &&
             (blk->hashval == args->hashval)) {
             error = xfs_da3_path_shift(state, &state->path, 1, 1,
                              &retval);
             if (error)
                 return error;
             if (retval == 0) {
                 continue;
             } else if (blk->magic == XFS_ATTR_LEAF_MAGIC) {
                 /* path_shift() gives ENOENT */
                 retval = -ENOATTR;
             }
         }
         break;
     }
     *result = retval;
     return 0;
 }
 
 /*========================================================================
  * Utility routines.
  *========================================================================*/
 
 /*
  * Compare two intermediate nodes for "order".
  */
 STATIC int
 xfs_da3_node_order(
     struct xfs_inode *dp,
     struct xfs_buf  *node1_bp,
     struct xfs_buf  *node2_bp)
 {
     struct xfs_da_intnode   *node1;
     struct xfs_da_intnode   *node2;
     struct xfs_da_node_entry *btree1;
     struct xfs_da_node_entry *btree2;
     struct xfs_da3_icnode_hdr node1hdr;
     struct xfs_da3_icnode_hdr node2hdr;
 
     node1 = node1_bp->b_addr;
     node2 = node2_bp->b_addr;
     xfs_da3_node_hdr_from_disk(dp->i_mount, &node1hdr, node1);
     xfs_da3_node_hdr_from_disk(dp->i_mount, &node2hdr, node2);
     btree1 = node1hdr.btree;
     btree2 = node2hdr.btree;
 
     if (node1hdr.count > 0 && node2hdr.count > 0 &&
         ((be32_to_cpu(btree2[0].hashval) < be32_to_cpu(btree1[0].hashval)) ||
          (be32_to_cpu(btree2[node2hdr.count - 1].hashval) <
           be32_to_cpu(btree1[node1hdr.count - 1].hashval)))) {
         return 1;
     }
     return 0;
 }
 
 /*
  * Link a new block into a doubly linked list of blocks (of whatever type).
  */
 int                         /* error */
 xfs_da3_blk_link(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *old_blk,
     struct xfs_da_state_blk *new_blk)
 {
     struct xfs_da_blkinfo   *old_info;
     struct xfs_da_blkinfo   *new_info;
     struct xfs_da_blkinfo   *tmp_info;
     struct xfs_da_args  *args;
     struct xfs_buf      *bp;
     int         before = 0;
     int         error;
     struct xfs_inode    *dp = state->args->dp;
 
     /*
      * Set up environment.
      */
     args = state->args;
     ASSERT(args != NULL);
     old_info = old_blk->bp->b_addr;
     new_info = new_blk->bp->b_addr;
     ASSERT(old_blk->magic == XFS_DA_NODE_MAGIC ||
            old_blk->magic == XFS_DIR2_LEAFN_MAGIC ||
            old_blk->magic == XFS_ATTR_LEAF_MAGIC);
 
     switch (old_blk->magic) {
     case XFS_ATTR_LEAF_MAGIC:
         before = xfs_attr_leaf_order(old_blk->bp, new_blk->bp);
         break;
     case XFS_DIR2_LEAFN_MAGIC:
         before = xfs_dir2_leafn_order(dp, old_blk->bp, new_blk->bp);
         break;
     case XFS_DA_NODE_MAGIC:
         before = xfs_da3_node_order(dp, old_blk->bp, new_blk->bp);
         break;
     }
 
     /*
      * Link blocks in appropriate order.
      */
     if (before) {
         /*
          * Link new block in before existing block.
          */
         trace_xfs_da_link_before(args);
         new_info->forw = cpu_to_be32(old_blk->blkno);
         new_info->back = old_info->back;
         if (old_info->back) {
             error = xfs_da3_node_read(args->trans, dp,
                         be32_to_cpu(old_info->back),
                         &bp, args->whichfork);
             if (error)
                 return error;
             ASSERT(bp != NULL);
             tmp_info = bp->b_addr;
             ASSERT(tmp_info->magic == old_info->magic);
             ASSERT(be32_to_cpu(tmp_info->forw) == old_blk->blkno);
             tmp_info->forw = cpu_to_be32(new_blk->blkno);
             xfs_trans_log_buf(args->trans, bp, 0, sizeof(*tmp_info)-1);
         }
         old_info->back = cpu_to_be32(new_blk->blkno);
     } else {
         /*
          * Link new block in after existing block.
          */
         trace_xfs_da_link_after(args);
         new_info->forw = old_info->forw;
         new_info->back = cpu_to_be32(old_blk->blkno);
         if (old_info->forw) {
             error = xfs_da3_node_read(args->trans, dp,
                         be32_to_cpu(old_info->forw),
                         &bp, args->whichfork);
             if (error)
                 return error;
             ASSERT(bp != NULL);
             tmp_info = bp->b_addr;
             ASSERT(tmp_info->magic == old_info->magic);
             ASSERT(be32_to_cpu(tmp_info->back) == old_blk->blkno);
             tmp_info->back = cpu_to_be32(new_blk->blkno);
             xfs_trans_log_buf(args->trans, bp, 0, sizeof(*tmp_info)-1);
         }
         old_info->forw = cpu_to_be32(new_blk->blkno);
     }
 
     xfs_trans_log_buf(args->trans, old_blk->bp, 0, sizeof(*tmp_info) - 1);
     xfs_trans_log_buf(args->trans, new_blk->bp, 0, sizeof(*tmp_info) - 1);
     return 0;
 }
 
 /*
  * Unlink a block from a doubly linked list of blocks.
  */
 STATIC int                      /* error */
 xfs_da3_blk_unlink(
     struct xfs_da_state *state,
     struct xfs_da_state_blk *drop_blk,
     struct xfs_da_state_blk *save_blk)
 {
     struct xfs_da_blkinfo   *drop_info;
     struct xfs_da_blkinfo   *save_info;
     struct xfs_da_blkinfo   *tmp_info;
     struct xfs_da_args  *args;
     struct xfs_buf      *bp;
     int         error;
 
     /*
      * Set up environment.
      */
     args = state->args;
     ASSERT(args != NULL);
     save_info = save_blk->bp->b_addr;
     drop_info = drop_blk->bp->b_addr;
     ASSERT(save_blk->magic == XFS_DA_NODE_MAGIC ||
            save_blk->magic == XFS_DIR2_LEAFN_MAGIC ||
            save_blk->magic == XFS_ATTR_LEAF_MAGIC);
     ASSERT(save_blk->magic == drop_blk->magic);
     ASSERT((be32_to_cpu(save_info->forw) == drop_blk->blkno) ||
            (be32_to_cpu(save_info->back) == drop_blk->blkno));
     ASSERT((be32_to_cpu(drop_info->forw) == save_blk->blkno) ||
            (be32_to_cpu(drop_info->back) == save_blk->blkno));
 
     /*
      * Unlink the leaf block from the doubly linked chain of leaves.
      */
     if (be32_to_cpu(save_info->back) == drop_blk->blkno) {
         trace_xfs_da_unlink_back(args);
         save_info->back = drop_info->back;
         if (drop_info->back) {
             error = xfs_da3_node_read(args->trans, args->dp,
                         be32_to_cpu(drop_info->back),
                         &bp, args->whichfork);
             if (error)
                 return error;
             ASSERT(bp != NULL);
             tmp_info = bp->b_addr;
             ASSERT(tmp_info->magic == save_info->magic);
             ASSERT(be32_to_cpu(tmp_info->forw) == drop_blk->blkno);
             tmp_info->forw = cpu_to_be32(save_blk->blkno);
             xfs_trans_log_buf(args->trans, bp, 0,
                             sizeof(*tmp_info) - 1);
         }
     } else {
         trace_xfs_da_unlink_forward(args);
         save_info->forw = drop_info->forw;
         if (drop_info->forw) {
             error = xfs_da3_node_read(args->trans, args->dp,
                         be32_to_cpu(drop_info->forw),
                         &bp, args->whichfork);
             if (error)
                 return error;
             ASSERT(bp != NULL);
             tmp_info = bp->b_addr;
             ASSERT(tmp_info->magic == save_info->magic);
             ASSERT(be32_to_cpu(tmp_info->back) == drop_blk->blkno);
             tmp_info->back = cpu_to_be32(save_blk->blkno);
             xfs_trans_log_buf(args->trans, bp, 0,
                             sizeof(*tmp_info) - 1);
         }
     }
 
     xfs_trans_log_buf(args->trans, save_blk->bp, 0, sizeof(*save_info) - 1);
     return 0;
 }
 
 /*
  * Move a path "forward" or "!forward" one block at the current level.
  *
  * This routine will adjust a "path" to point to the next block
  * "forward" (higher hashvalues) or "!forward" (lower hashvals) in the
  * Btree, including updating pointers to the intermediate nodes between
  * the new bottom and the root.
  */
 int                         /* error */
 xfs_da3_path_shift(
     struct xfs_da_state *state,
     struct xfs_da_state_path *path,
     int         forward,
     int         release,
     int         *result)
 {
     struct xfs_da_state_blk *blk;
     struct xfs_da_blkinfo   *info;
     struct xfs_da_args  *args;
     struct xfs_da_node_entry *btree;
     struct xfs_da3_icnode_hdr nodehdr;
     struct xfs_buf      *bp;
     xfs_dablk_t     blkno = 0;
     int         level;
     int         error;
     struct xfs_inode    *dp = state->args->dp;
 
     trace_xfs_da_path_shift(state->args);
 
     /*
      * Roll up the Btree looking for the first block where our
      * current index is not at the edge of the block.  Note that
      * we skip the bottom layer because we want the sibling block.
      */
     args = state->args;
     ASSERT(args != NULL);
     ASSERT(path != NULL);
     ASSERT((path->active > 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
     level = (path->active-1) - 1;   /* skip bottom layer in path */
     for (; level >= 0; level--) {
         blk = &path->blk[level];
         xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr,
                        blk->bp->b_addr);
 
         if (forward && (blk->index < nodehdr.count - 1)) {
             blk->index++;
             blkno = be32_to_cpu(nodehdr.btree[blk->index].before);
             break;
         } else if (!forward && (blk->index > 0)) {
             blk->index--;
             blkno = be32_to_cpu(nodehdr.btree[blk->index].before);
             break;
         }
     }
     if (level < 0) {
         *result = -ENOENT;  /* we're out of our tree */
         ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);
         return 0;
     }
 
     /*
      * Roll down the edge of the subtree until we reach the
      * same depth we were at originally.
      */
     for (blk++, level++; level < path->active; blk++, level++) {
         /*
          * Read the next child block into a local buffer.
          */
         error = xfs_da3_node_read(args->trans, dp, blkno, &bp,
                       args->whichfork);
         if (error)
             return error;
 
         /*
          * Release the old block (if it's dirty, the trans doesn't
          * actually let go) and swap the local buffer into the path
          * structure. This ensures failure of the above read doesn't set
          * a NULL buffer in an active slot in the path.
          */
         if (release)
             xfs_trans_brelse(args->trans, blk->bp);
         blk->blkno = blkno;
         blk->bp = bp;
 
         info = blk->bp->b_addr;
         ASSERT(info->magic == cpu_to_be16(XFS_DA_NODE_MAGIC) ||
                info->magic == cpu_to_be16(XFS_DA3_NODE_MAGIC) ||
                info->magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
                info->magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC) ||
                info->magic == cpu_to_be16(XFS_ATTR_LEAF_MAGIC) ||
                info->magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC));
 
 
         /*
          * Note: we flatten the magic number to a single type so we
          * don't have to compare against crc/non-crc types elsewhere.
          */
         switch (be16_to_cpu(info->magic)) {
         case XFS_DA_NODE_MAGIC:
         case XFS_DA3_NODE_MAGIC:
             blk->magic = XFS_DA_NODE_MAGIC;
             xfs_da3_node_hdr_from_disk(dp->i_mount, &nodehdr,
                            bp->b_addr);
             btree = nodehdr.btree;
             blk->hashval = be32_to_cpu(btree[nodehdr.count - 1].hashval);
             if (forward)
                 blk->index = 0;
             else
                 blk->index = nodehdr.count - 1;
             blkno = be32_to_cpu(btree[blk->index].before);
             break;
         case XFS_ATTR_LEAF_MAGIC:
         case XFS_ATTR3_LEAF_MAGIC:
             blk->magic = XFS_ATTR_LEAF_MAGIC;
             ASSERT(level == path->active-1);
             blk->index = 0;
             blk->hashval = xfs_attr_leaf_lasthash(blk->bp, NULL);
             break;
         case XFS_DIR2_LEAFN_MAGIC:
         case XFS_DIR3_LEAFN_MAGIC:
             blk->magic = XFS_DIR2_LEAFN_MAGIC;
             ASSERT(level == path->active-1);
             blk->index = 0;
             blk->hashval = xfs_dir2_leaf_lasthash(args->dp,
                                   blk->bp, NULL);
             break;
         default:
             ASSERT(0);
             break;
         }
     }
     *result = 0;
     return 0;
 }
 
 
 /*========================================================================
  * Utility routines.
  *========================================================================*/
 
 /*
  * Implement a simple hash on a character string.
  * Rotate the hash value by 7 bits, then XOR each character in.
  * This is implemented with some source-level loop unrolling.
  */
 xfs_dahash_t
 xfs_da_hashname(const uint8_t *name, int namelen)
 {
     xfs_dahash_t hash;
 
     /*
      * Do four characters at a time as long as we can.
      */
     for (hash = 0; namelen >= 4; namelen -= 4, name += 4)
         hash = (name[0] << 21) ^ (name[1] << 14) ^ (name[2] << 7) ^
                (name[3] << 0) ^ rol32(hash, 7 * 4);
 
     /*
      * Now do the rest of the characters.
      */
     switch (namelen) {
     case 3:
         return (name[0] << 14) ^ (name[1] << 7) ^ (name[2] << 0) ^
                rol32(hash, 7 * 3);
     case 2:
         return (name[0] << 7) ^ (name[1] << 0) ^ rol32(hash, 7 * 2);
     case 1:
         return (name[0] << 0) ^ rol32(hash, 7 * 1);
     default: /* case 0: */
         return hash;
     }
 }
 
 enum xfs_dacmp
 xfs_da_compname(
     struct xfs_da_args *args,
     const unsigned char *name,
     int     len)
 {
     return (args->namelen == len && memcmp(args->name, name, len) == 0) ?
                     XFS_CMP_EXACT : XFS_CMP_DIFFERENT;
 }
 
 int
 xfs_da_grow_inode_int(
     struct xfs_da_args  *args,
     xfs_fileoff_t       *bno,
     int         count)
 {
     struct xfs_trans    *tp = args->trans;
     struct xfs_inode    *dp = args->dp;
     int         w = args->whichfork;
     xfs_rfsblock_t      nblks = dp->i_nblocks;
     struct xfs_bmbt_irec    map, *mapp;
     int         nmap, error, got, i, mapi;
 
     /*
      * Find a spot in the file space to put the new block.
      */
     error = xfs_bmap_first_unused(tp, dp, count, bno, w);
     if (error)
         return error;
 
     /*
      * Try mapping it in one filesystem block.
      */
     nmap = 1;
     error = xfs_bmapi_write(tp, dp, *bno, count,
             xfs_bmapi_aflag(w)|XFS_BMAPI_METADATA|XFS_BMAPI_CONTIG,
             args->total, &map, &nmap);
     if (error)
         return error;
 
     ASSERT(nmap <= 1);
     if (nmap == 1) {
         mapp = &map;
         mapi = 1;
     } else if (nmap == 0 && count > 1) {
         xfs_fileoff_t       b;
         int         c;
 
         /*
          * If we didn't get it and the block might work if fragmented,
          * try without the CONTIG flag.  Loop until we get it all.
          */
         mapp = kmem_alloc(sizeof(*mapp) * count, 0);
         for (b = *bno, mapi = 0; b < *bno + count; ) {
             nmap = min(XFS_BMAP_MAX_NMAP, count);
             c = (int)(*bno + count - b);
             error = xfs_bmapi_write(tp, dp, b, c,
                     xfs_bmapi_aflag(w)|XFS_BMAPI_METADATA,
                     args->total, &mapp[mapi], &nmap);
             if (error)
                 goto out_free_map;
             if (nmap < 1)
                 break;
             mapi += nmap;
             b = mapp[mapi - 1].br_startoff +
                 mapp[mapi - 1].br_blockcount;
         }
     } else {
         mapi = 0;
         mapp = NULL;
     }
 
     /*
      * Count the blocks we got, make sure it matches the total.
      */
     for (i = 0, got = 0; i < mapi; i++)
         got += mapp[i].br_blockcount;
     if (got != count || mapp[0].br_startoff != *bno ||
         mapp[mapi - 1].br_startoff + mapp[mapi - 1].br_blockcount !=
         *bno + count) {
         error = -ENOSPC;
         goto out_free_map;
     }
 
     /* account for newly allocated blocks in reserved blocks total */
     args->total -= dp->i_nblocks - nblks;
 
 out_free_map:
     if (mapp != &map)
         kmem_free(mapp);
     return error;
 }
 
 /*
  * Add a block to the btree ahead of the file.
  * Return the new block number to the caller.
  */
 int
 xfs_da_grow_inode(
     struct xfs_da_args  *args,
     xfs_dablk_t     *new_blkno)
 {
     xfs_fileoff_t       bno;
     int         error;
 
     trace_xfs_da_grow_inode(args);
 
     bno = args->geo->leafblk;
     error = xfs_da_grow_inode_int(args, &bno, args->geo->fsbcount);
     if (!error)
         *new_blkno = (xfs_dablk_t)bno;
     return error;
 }
 
 /*
  * Ick.  We need to always be able to remove a btree block, even
  * if there's no space reservation because the filesystem is full.
  * This is called if xfs_bunmapi on a btree block fails due to ENOSPC.
  * It swaps the target block with the last block in the file.  The
  * last block in the file can always be removed since it can't cause
  * a bmap btree split to do that.
  */
 STATIC int
 xfs_da3_swap_lastblock(
     struct xfs_da_args  *args,
     xfs_dablk_t     *dead_blknop,
     struct xfs_buf      **dead_bufp)
 {
     struct xfs_da_blkinfo   *dead_info;
     struct xfs_da_blkinfo   *sib_info;
     struct xfs_da_intnode   *par_node;
     struct xfs_da_intnode   *dead_node;
     struct xfs_dir2_leaf    *dead_leaf2;
     struct xfs_da_node_entry *btree;
     struct xfs_da3_icnode_hdr par_hdr;
     struct xfs_inode    *dp;
     struct xfs_trans    *tp;
     struct xfs_mount    *mp;
     struct xfs_buf      *dead_buf;
     struct xfs_buf      *last_buf;
     struct xfs_buf      *sib_buf;
     struct xfs_buf      *par_buf;
     xfs_dahash_t        dead_hash;
     xfs_fileoff_t       lastoff;
     xfs_dablk_t     dead_blkno;
     xfs_dablk_t     last_blkno;
     xfs_dablk_t     sib_blkno;
     xfs_dablk_t     par_blkno;
     int         error;
     int         w;
     int         entno;
     int         level;
     int         dead_level;
 
     trace_xfs_da_swap_lastblock(args);
 
     dead_buf = *dead_bufp;
     dead_blkno = *dead_blknop;
     tp = args->trans;
     dp = args->dp;
     w = args->whichfork;
     ASSERT(w == XFS_DATA_FORK);
     mp = dp->i_mount;
     lastoff = args->geo->freeblk;
     error = xfs_bmap_last_before(tp, dp, &lastoff, w);
     if (error)
         return error;
     if (XFS_IS_CORRUPT(mp, lastoff == 0))
         return -EFSCORRUPTED;
     /*
      * Read the last block in the btree space.
      */
     last_blkno = (xfs_dablk_t)lastoff - args->geo->fsbcount;
     error = xfs_da3_node_read(tp, dp, last_blkno, &last_buf, w);
     if (error)
         return error;
     /*
      * Copy the last block into the dead buffer and log it.
      */
     memcpy(dead_buf->b_addr, last_buf->b_addr, args->geo->blksize);
     xfs_trans_log_buf(tp, dead_buf, 0, args->geo->blksize - 1);
     dead_info = dead_buf->b_addr;
     /*
      * Get values from the moved block.
      */
     if (dead_info->magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
         dead_info->magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
         struct xfs_dir3_icleaf_hdr leafhdr;
         struct xfs_dir2_leaf_entry *ents;
 
         dead_leaf2 = (xfs_dir2_leaf_t *)dead_info;
         xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &leafhdr,
                         dead_leaf2);
         ents = leafhdr.ents;
         dead_level = 0;
         dead_hash = be32_to_cpu(ents[leafhdr.count - 1].hashval);
     } else {
         struct xfs_da3_icnode_hdr deadhdr;
 
         dead_node = (xfs_da_intnode_t *)dead_info;
         xfs_da3_node_hdr_from_disk(dp->i_mount, &deadhdr, dead_node);
         btree = deadhdr.btree;
         dead_level = deadhdr.level;
         dead_hash = be32_to_cpu(btree[deadhdr.count - 1].hashval);
     }
     sib_buf = par_buf = NULL;
     /*
      * If the moved block has a left sibling, fix up the pointers.
      */
     if ((sib_blkno = be32_to_cpu(dead_info->back))) {
         error = xfs_da3_node_read(tp, dp, sib_blkno, &sib_buf, w);
         if (error)
             goto done;
         sib_info = sib_buf->b_addr;
         if (XFS_IS_CORRUPT(mp,
                    be32_to_cpu(sib_info->forw) != last_blkno ||
                    sib_info->magic != dead_info->magic)) {
             error = -EFSCORRUPTED;
             goto done;
         }
         sib_info->forw = cpu_to_be32(dead_blkno);
         xfs_trans_log_buf(tp, sib_buf,
             XFS_DA_LOGRANGE(sib_info, &sib_info->forw,
                     sizeof(sib_info->forw)));
         sib_buf = NULL;
     }
     /*
      * If the moved block has a right sibling, fix up the pointers.
      */
     if ((sib_blkno = be32_to_cpu(dead_info->forw))) {
         error = xfs_da3_node_read(tp, dp, sib_blkno, &sib_buf, w);
         if (error)
             goto done;
         sib_info = sib_buf->b_addr;
         if (XFS_IS_CORRUPT(mp,
                    be32_to_cpu(sib_info->back) != last_blkno ||
                    sib_info->magic != dead_info->magic)) {
             error = -EFSCORRUPTED;
             goto done;
         }
         sib_info->back = cpu_to_be32(dead_blkno);
         xfs_trans_log_buf(tp, sib_buf,
             XFS_DA_LOGRANGE(sib_info, &sib_info->back,
                     sizeof(sib_info->back)));
         sib_buf = NULL;
     }
     par_blkno = args->geo->leafblk;
     level = -1;
     /*
      * Walk down the tree looking for the parent of the moved block.
      */
     for (;;) {
         error = xfs_da3_node_read(tp, dp, par_blkno, &par_buf, w);
         if (error)
             goto done;
         par_node = par_buf->b_addr;
         xfs_da3_node_hdr_from_disk(dp->i_mount, &par_hdr, par_node);
         if (XFS_IS_CORRUPT(mp,
                    level >= 0 && level != par_hdr.level + 1)) {
             error = -EFSCORRUPTED;
             goto done;
         }
         level = par_hdr.level;
         btree = par_hdr.btree;
         for (entno = 0;
              entno < par_hdr.count &&
              be32_to_cpu(btree[entno].hashval) < dead_hash;
              entno++)
             continue;
         if (XFS_IS_CORRUPT(mp, entno == par_hdr.count)) {
             error = -EFSCORRUPTED;
             goto done;
         }
         par_blkno = be32_to_cpu(btree[entno].before);
         if (level == dead_level + 1)
             break;
         xfs_trans_brelse(tp, par_buf);
         par_buf = NULL;
     }
     /*
      * We're in the right parent block.
      * Look for the right entry.
      */
     for (;;) {
         for (;
              entno < par_hdr.count &&
              be32_to_cpu(btree[entno].before) != last_blkno;
              entno++)
             continue;
         if (entno < par_hdr.count)
             break;
         par_blkno = par_hdr.forw;
         xfs_trans_brelse(tp, par_buf);
         par_buf = NULL;
         if (XFS_IS_CORRUPT(mp, par_blkno == 0)) {
             error = -EFSCORRUPTED;
             goto done;
         }
         error = xfs_da3_node_read(tp, dp, par_blkno, &par_buf, w);
         if (error)
             goto done;
         par_node = par_buf->b_addr;
         xfs_da3_node_hdr_from_disk(dp->i_mount, &par_hdr, par_node);
         if (XFS_IS_CORRUPT(mp, par_hdr.level != level)) {
             error = -EFSCORRUPTED;
             goto done;
         }
         btree = par_hdr.btree;
         entno = 0;
     }
     /*
      * Update the parent entry pointing to the moved block.
      */
     btree[entno].before = cpu_to_be32(dead_blkno);
     xfs_trans_log_buf(tp, par_buf,
         XFS_DA_LOGRANGE(par_node, &btree[entno].before,
                 sizeof(btree[entno].before)));
     *dead_blknop = last_blkno;
     *dead_bufp = last_buf;
     return 0;
 done:
     if (par_buf)
         xfs_trans_brelse(tp, par_buf);
     if (sib_buf)
         xfs_trans_brelse(tp, sib_buf);
     xfs_trans_brelse(tp, last_buf);
     return error;
 }
 
 /*
  * Remove a btree block from a directory or attribute.
  */
 int
 xfs_da_shrink_inode(
     struct xfs_da_args  *args,
     xfs_dablk_t     dead_blkno,
     struct xfs_buf      *dead_buf)
 {
     struct xfs_inode    *dp;
     int         done, error, w, count;
     struct xfs_trans    *tp;
 
     trace_xfs_da_shrink_inode(args);
 
     dp = args->dp;
     w = args->whichfork;
     tp = args->trans;
     count = args->geo->fsbcount;
     for (;;) {
         /*
          * Remove extents.  If we get ENOSPC for a dir we have to move
          * the last block to the place we want to kill.
          */
         error = xfs_bunmapi(tp, dp, dead_blkno, count,
                     xfs_bmapi_aflag(w), 0, &done);
         if (error == -ENOSPC) {
             if (w != XFS_DATA_FORK)
                 break;
             error = xfs_da3_swap_lastblock(args, &dead_blkno,
                               &dead_buf);
             if (error)
                 break;
         } else {
             break;
         }
     }
     xfs_trans_binval(tp, dead_buf);
     return error;
 }
 
 static int
 xfs_dabuf_map(
     struct xfs_inode    *dp,
     xfs_dablk_t     bno,
     unsigned int        flags,
     int         whichfork,
     struct xfs_buf_map  **mapp,
     int         *nmaps)
 {
     struct xfs_mount    *mp = dp->i_mount;
     int         nfsb = xfs_dabuf_nfsb(mp, whichfork);
     struct xfs_bmbt_irec    irec, *irecs = &irec;
     struct xfs_buf_map  *map = *mapp;
     xfs_fileoff_t       off = bno;
     int         error = 0, nirecs, i;
 
     if (nfsb > 1)
         irecs = kmem_zalloc(sizeof(irec) * nfsb, KM_NOFS);
 
     nirecs = nfsb;
     error = xfs_bmapi_read(dp, bno, nfsb, irecs, &nirecs,
             xfs_bmapi_aflag(whichfork));
     if (error)
         goto out_free_irecs;
 
     /*
      * Use the caller provided map for the single map case, else allocate a
      * larger one that needs to be free by the caller.
      */
     if (nirecs > 1) {
         map = kmem_zalloc(nirecs * sizeof(struct xfs_buf_map), KM_NOFS);
         if (!map) {
             error = -ENOMEM;
             goto out_free_irecs;
         }
         *mapp = map;
     }
 
     for (i = 0; i < nirecs; i++) {
         if (irecs[i].br_startblock == HOLESTARTBLOCK ||
             irecs[i].br_startblock == DELAYSTARTBLOCK)
             goto invalid_mapping;
         if (off != irecs[i].br_startoff)
             goto invalid_mapping;
 
         map[i].bm_bn = XFS_FSB_TO_DADDR(mp, irecs[i].br_startblock);
         map[i].bm_len = XFS_FSB_TO_BB(mp, irecs[i].br_blockcount);
         off += irecs[i].br_blockcount;
     }
 
     if (off != bno + nfsb)
         goto invalid_mapping;
 
     *nmaps = nirecs;
 out_free_irecs:
     if (irecs != &irec)
         kmem_free(irecs);
     return error;
 
 invalid_mapping:
     /* Caller ok with no mapping. */
     if (XFS_IS_CORRUPT(mp, !(flags & XFS_DABUF_MAP_HOLE_OK))) {
         error = -EFSCORRUPTED;
         if (xfs_error_level >= XFS_ERRLEVEL_LOW) {
             xfs_alert(mp, "%s: bno %u inode %llu",
                     __func__, bno, dp->i_ino);
 
             for (i = 0; i < nirecs; i++) {
                 xfs_alert(mp,
 "[%02d] br_startoff %lld br_startblock %lld br_blockcount %lld br_state %d",
                     i, irecs[i].br_startoff,
                     irecs[i].br_startblock,
                     irecs[i].br_blockcount,
                     irecs[i].br_state);
             }
         }
     } else {
         *nmaps = 0;
     }
     goto out_free_irecs;
 }
 
 /*
  * Get a buffer for the dir/attr block.
  */
 int
 xfs_da_get_buf(
     struct xfs_trans    *tp,
     struct xfs_inode    *dp,
     xfs_dablk_t     bno,
     struct xfs_buf      **bpp,
     int         whichfork)
 {
     struct xfs_mount    *mp = dp->i_mount;
     struct xfs_buf      *bp;
     struct xfs_buf_map  map, *mapp = &map;
     int         nmap = 1;
     int         error;
 
     *bpp = NULL;
     error = xfs_dabuf_map(dp, bno, 0, whichfork, &mapp, &nmap);
     if (error || nmap == 0)
         goto out_free;
 
     error = xfs_trans_get_buf_map(tp, mp->m_ddev_targp, mapp, nmap, 0, &bp);
     if (error)
         goto out_free;
 
     *bpp = bp;
 
 out_free:
     if (mapp != &map)
         kmem_free(mapp);
 
     return error;
 }
 
 /*
  * Get a buffer for the dir/attr block, fill in the contents.
  */
 int
 xfs_da_read_buf(
     struct xfs_trans    *tp,
     struct xfs_inode    *dp,
     xfs_dablk_t     bno,
     unsigned int        flags,
     struct xfs_buf      **bpp,
     int         whichfork,
     const struct xfs_buf_ops *ops)
 {
     struct xfs_mount    *mp = dp->i_mount;
     struct xfs_buf      *bp;
     struct xfs_buf_map  map, *mapp = &map;
     int         nmap = 1;
     int         error;
 
     *bpp = NULL;
     error = xfs_dabuf_map(dp, bno, flags, whichfork, &mapp, &nmap);
     if (error || !nmap)
         goto out_free;
 
     error = xfs_trans_read_buf_map(mp, tp, mp->m_ddev_targp, mapp, nmap, 0,
             &bp, ops);
     if (error)
         goto out_free;
 
     if (whichfork == XFS_ATTR_FORK)
         xfs_buf_set_ref(bp, XFS_ATTR_BTREE_REF);
     else
         xfs_buf_set_ref(bp, XFS_DIR_BTREE_REF);
     *bpp = bp;
 out_free:
     if (mapp != &map)
         kmem_free(mapp);
 
     return error;
 }
 
 /*
  * Readahead the dir/attr block.
  */
 int
 xfs_da_reada_buf(
     struct xfs_inode    *dp,
     xfs_dablk_t     bno,
     unsigned int        flags,
     int         whichfork,
     const struct xfs_buf_ops *ops)
 {
     struct xfs_buf_map  map;
     struct xfs_buf_map  *mapp;
     int         nmap;
     int         error;
 
     mapp = &map;
     nmap = 1;
     error = xfs_dabuf_map(dp, bno, flags, whichfork, &mapp, &nmap);
     if (error || !nmap)
         goto out_free;
 
     xfs_buf_readahead_map(dp->i_mount->m_ddev_targp, mapp, nmap, ops);
 
 out_free:
     if (mapp != &map)
         kmem_free(mapp);
 
     return error;
 }