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xfs_dir2_block.c

/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * 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_types.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_dir2_data.h"
#include "xfs_dir2_leaf.h"
#include "xfs_dir2_block.h"
#include "xfs_dir2_trace.h"
#include "xfs_error.h"

/*
 * Local function prototypes.
 */
static void xfs_dir2_block_log_leaf(xfs_trans_t *tp, xfs_dabuf_t *bp, int first,
                            int last);
static void xfs_dir2_block_log_tail(xfs_trans_t *tp, xfs_dabuf_t *bp);
static int xfs_dir2_block_lookup_int(xfs_da_args_t *args, xfs_dabuf_t **bpp,
                             int *entno);
static int xfs_dir2_block_sort(const void *a, const void *b);

static xfs_dahash_t xfs_dir_hash_dot, xfs_dir_hash_dotdot;

/*
 * One-time startup routine called from xfs_init().
 */
void
xfs_dir_startup(void)
{
      xfs_dir_hash_dot = xfs_da_hashname(".", 1);
      xfs_dir_hash_dotdot = xfs_da_hashname("..", 2);
}

/*
 * Add an entry to a block directory.
 */
int                                 /* error */
xfs_dir2_block_addname(
      xfs_da_args_t           *args)            /* directory op arguments */
{
      xfs_dir2_data_free_t    *bf;        /* bestfree table in block */
      xfs_dir2_block_t  *block;           /* directory block structure */
      xfs_dir2_leaf_entry_t   *blp;       /* block leaf entries */
      xfs_dabuf_t       *bp;        /* buffer for block */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      int               compact;    /* need to compact leaf ents */
      xfs_dir2_data_entry_t   *dep;       /* block data entry */
      xfs_inode_t       *dp;        /* directory inode */
      xfs_dir2_data_unused_t  *dup;       /* block unused entry */
      int               error;            /* error return value */
      xfs_dir2_data_unused_t  *enddup=NULL;     /* unused at end of data */
      xfs_dahash_t            hash;       /* hash value of found entry */
      int               high;       /* high index for binary srch */
      int               highstale;  /* high stale index */
      int               lfloghigh=0;      /* last final leaf to log */
      int               lfloglow=0; /* first final leaf to log */
      int               len;        /* length of the new entry */
      int               low;        /* low index for binary srch */
      int               lowstale;   /* low stale index */
      int               mid=0;            /* midpoint for binary srch */
      xfs_mount_t       *mp;        /* filesystem mount point */
      int               needlog;    /* need to log header */
      int               needscan;   /* need to rescan freespace */
      __be16                  *tagp;            /* pointer to tag value */
      xfs_trans_t       *tp;        /* transaction structure */

      xfs_dir2_trace_args("block_addname", args);
      dp = args->dp;
      tp = args->trans;
      mp = dp->i_mount;
      /*
       * Read the (one and only) directory block into dabuf bp.
       */
      if ((error =
          xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &bp, XFS_DATA_FORK))) {
            return error;
      }
      ASSERT(bp != NULL);
      block = bp->data;
      /*
       * Check the magic number, corrupted if wrong.
       */
      if (unlikely(be32_to_cpu(block->hdr.magic) != XFS_DIR2_BLOCK_MAGIC)) {
            XFS_CORRUPTION_ERROR("xfs_dir2_block_addname",
                             XFS_ERRLEVEL_LOW, mp, block);
            xfs_da_brelse(tp, bp);
            return XFS_ERROR(EFSCORRUPTED);
      }
      len = xfs_dir2_data_entsize(args->namelen);
      /*
       * Set up pointers to parts of the block.
       */
      bf = block->hdr.bestfree;
      btp = xfs_dir2_block_tail_p(mp, block);
      blp = xfs_dir2_block_leaf_p(btp);
      /*
       * No stale entries?  Need space for entry and new leaf.
       */
      if (!btp->stale) {
            /*
             * Tag just before the first leaf entry.
             */
            tagp = (__be16 *)blp - 1;
            /*
             * Data object just before the first leaf entry.
             */
            enddup = (xfs_dir2_data_unused_t *)((char *)block + be16_to_cpu(*tagp));
            /*
             * If it's not free then can't do this add without cleaning up:
             * the space before the first leaf entry needs to be free so it
             * can be expanded to hold the pointer to the new entry.
             */
            if (be16_to_cpu(enddup->freetag) != XFS_DIR2_DATA_FREE_TAG)
                  dup = enddup = NULL;
            /*
             * Check out the biggest freespace and see if it's the same one.
             */
            else {
                  dup = (xfs_dir2_data_unused_t *)
                        ((char *)block + be16_to_cpu(bf[0].offset));
                  if (dup == enddup) {
                        /*
                         * It is the biggest freespace, is it too small
                         * to hold the new leaf too?
                         */
                        if (be16_to_cpu(dup->length) < len + (uint)sizeof(*blp)) {
                              /*
                               * Yes, we use the second-largest
                               * entry instead if it works.
                               */
                              if (be16_to_cpu(bf[1].length) >= len)
                                    dup = (xfs_dir2_data_unused_t *)
                                          ((char *)block +
                                           be16_to_cpu(bf[1].offset));
                              else
                                    dup = NULL;
                        }
                  } else {
                        /*
                         * Not the same free entry,
                         * just check its length.
                         */
                        if (be16_to_cpu(dup->length) < len) {
                              dup = NULL;
                        }
                  }
            }
            compact = 0;
      }
      /*
       * If there are stale entries we'll use one for the leaf.
       * Is the biggest entry enough to avoid compaction?
       */
      else if (be16_to_cpu(bf[0].length) >= len) {
            dup = (xfs_dir2_data_unused_t *)
                  ((char *)block + be16_to_cpu(bf[0].offset));
            compact = 0;
      }
      /*
       * Will need to compact to make this work.
       */
      else {
            /*
             * Tag just before the first leaf entry.
             */
            tagp = (__be16 *)blp - 1;
            /*
             * Data object just before the first leaf entry.
             */
            dup = (xfs_dir2_data_unused_t *)((char *)block + be16_to_cpu(*tagp));
            /*
             * If it's not free then the data will go where the
             * leaf data starts now, if it works at all.
             */
            if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
                  if (be16_to_cpu(dup->length) + (be32_to_cpu(btp->stale) - 1) *
                      (uint)sizeof(*blp) < len)
                        dup = NULL;
            } else if ((be32_to_cpu(btp->stale) - 1) * (uint)sizeof(*blp) < len)
                  dup = NULL;
            else
                  dup = (xfs_dir2_data_unused_t *)blp;
            compact = 1;
      }
      /*
       * If this isn't a real add, we're done with the buffer.
       */
      if (args->justcheck)
            xfs_da_brelse(tp, bp);
      /*
       * If we don't have space for the new entry & leaf ...
       */
      if (!dup) {
            /*
             * Not trying to actually do anything, or don't have
             * a space reservation: return no-space.
             */
            if (args->justcheck || args->total == 0)
                  return XFS_ERROR(ENOSPC);
            /*
             * Convert to the next larger format.
             * Then add the new entry in that format.
             */
            error = xfs_dir2_block_to_leaf(args, bp);
            xfs_da_buf_done(bp);
            if (error)
                  return error;
            return xfs_dir2_leaf_addname(args);
      }
      /*
       * Just checking, and it would work, so say so.
       */
      if (args->justcheck)
            return 0;
      needlog = needscan = 0;
      /*
       * If need to compact the leaf entries, do it now.
       * Leave the highest-numbered stale entry stale.
       * XXX should be the one closest to mid but mid is not yet computed.
       */
      if (compact) {
            int   fromidx;          /* source leaf index */
            int   toidx;                  /* target leaf index */

            for (fromidx = toidx = be32_to_cpu(btp->count) - 1,
                  highstale = lfloghigh = -1;
                 fromidx >= 0;
                 fromidx--) {
                  if (be32_to_cpu(blp[fromidx].address) == XFS_DIR2_NULL_DATAPTR) {
                        if (highstale == -1)
                              highstale = toidx;
                        else {
                              if (lfloghigh == -1)
                                    lfloghigh = toidx;
                              continue;
                        }
                  }
                  if (fromidx < toidx)
                        blp[toidx] = blp[fromidx];
                  toidx--;
            }
            lfloglow = toidx + 1 - (be32_to_cpu(btp->stale) - 1);
            lfloghigh -= be32_to_cpu(btp->stale) - 1;
            be32_add(&btp->count, -(be32_to_cpu(btp->stale) - 1));
            xfs_dir2_data_make_free(tp, bp,
                  (xfs_dir2_data_aoff_t)((char *)blp - (char *)block),
                  (xfs_dir2_data_aoff_t)((be32_to_cpu(btp->stale) - 1) * sizeof(*blp)),
                  &needlog, &needscan);
            blp += be32_to_cpu(btp->stale) - 1;
            btp->stale = cpu_to_be32(1);
            /*
             * If we now need to rebuild the bestfree map, do so.
             * This needs to happen before the next call to use_free.
             */
            if (needscan) {
                  xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog);
                  needscan = 0;
            }
      }
      /*
       * Set leaf logging boundaries to impossible state.
       * For the no-stale case they're set explicitly.
       */
      else if (btp->stale) {
            lfloglow = be32_to_cpu(btp->count);
            lfloghigh = -1;
      }
      /*
       * Find the slot that's first lower than our hash value, -1 if none.
       */
      for (low = 0, high = be32_to_cpu(btp->count) - 1; low <= high; ) {
            mid = (low + high) >> 1;
            if ((hash = be32_to_cpu(blp[mid].hashval)) == args->hashval)
                  break;
            if (hash < args->hashval)
                  low = mid + 1;
            else
                  high = mid - 1;
      }
      while (mid >= 0 && be32_to_cpu(blp[mid].hashval) >= args->hashval) {
            mid--;
      }
      /*
       * No stale entries, will use enddup space to hold new leaf.
       */
      if (!btp->stale) {
            /*
             * Mark the space needed for the new leaf entry, now in use.
             */
            xfs_dir2_data_use_free(tp, bp, enddup,
                  (xfs_dir2_data_aoff_t)
                  ((char *)enddup - (char *)block + be16_to_cpu(enddup->length) -
                   sizeof(*blp)),
                  (xfs_dir2_data_aoff_t)sizeof(*blp),
                  &needlog, &needscan);
            /*
             * Update the tail (entry count).
             */
            be32_add(&btp->count, 1);
            /*
             * If we now need to rebuild the bestfree map, do so.
             * This needs to happen before the next call to use_free.
             */
            if (needscan) {
                  xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block,
                        &needlog);
                  needscan = 0;
            }
            /*
             * Adjust pointer to the first leaf entry, we're about to move
             * the table up one to open up space for the new leaf entry.
             * Then adjust our index to match.
             */
            blp--;
            mid++;
            if (mid)
                  memmove(blp, &blp[1], mid * sizeof(*blp));
            lfloglow = 0;
            lfloghigh = mid;
      }
      /*
       * Use a stale leaf for our new entry.
       */
      else {
            for (lowstale = mid;
                 lowstale >= 0 &&
                  be32_to_cpu(blp[lowstale].address) != XFS_DIR2_NULL_DATAPTR;
                 lowstale--)
                  continue;
            for (highstale = mid + 1;
                 highstale < be32_to_cpu(btp->count) &&
                  be32_to_cpu(blp[highstale].address) != XFS_DIR2_NULL_DATAPTR &&
                  (lowstale < 0 || mid - lowstale > highstale - mid);
                 highstale++)
                  continue;
            /*
             * Move entries toward the low-numbered stale entry.
             */
            if (lowstale >= 0 &&
                (highstale == be32_to_cpu(btp->count) ||
                 mid - lowstale <= highstale - mid)) {
                  if (mid - lowstale)
                        memmove(&blp[lowstale], &blp[lowstale + 1],
                              (mid - lowstale) * sizeof(*blp));
                  lfloglow = MIN(lowstale, lfloglow);
                  lfloghigh = MAX(mid, lfloghigh);
            }
            /*
             * Move entries toward the high-numbered stale entry.
             */
            else {
                  ASSERT(highstale < be32_to_cpu(btp->count));
                  mid++;
                  if (highstale - mid)
                        memmove(&blp[mid + 1], &blp[mid],
                              (highstale - mid) * sizeof(*blp));
                  lfloglow = MIN(mid, lfloglow);
                  lfloghigh = MAX(highstale, lfloghigh);
            }
            be32_add(&btp->stale, -1);
      }
      /*
       * Point to the new data entry.
       */
      dep = (xfs_dir2_data_entry_t *)dup;
      /*
       * Fill in the leaf entry.
       */
      blp[mid].hashval = cpu_to_be32(args->hashval);
      blp[mid].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
                        (char *)dep - (char *)block));
      xfs_dir2_block_log_leaf(tp, bp, lfloglow, lfloghigh);
      /*
       * Mark space for the data entry used.
       */
      xfs_dir2_data_use_free(tp, bp, dup,
            (xfs_dir2_data_aoff_t)((char *)dup - (char *)block),
            (xfs_dir2_data_aoff_t)len, &needlog, &needscan);
      /*
       * Create the new data entry.
       */
      dep->inumber = cpu_to_be64(args->inumber);
      dep->namelen = args->namelen;
      memcpy(dep->name, args->name, args->namelen);
      tagp = xfs_dir2_data_entry_tag_p(dep);
      *tagp = cpu_to_be16((char *)dep - (char *)block);
      /*
       * Clean up the bestfree array and log the header, tail, and entry.
       */
      if (needscan)
            xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog);
      if (needlog)
            xfs_dir2_data_log_header(tp, bp);
      xfs_dir2_block_log_tail(tp, bp);
      xfs_dir2_data_log_entry(tp, bp, dep);
      xfs_dir2_data_check(dp, bp);
      xfs_da_buf_done(bp);
      return 0;
}

/*
 * Readdir for block directories.
 */
int                                 /* error */
xfs_dir2_block_getdents(
      xfs_inode_t       *dp,        /* incore inode */
      void              *dirent,
      xfs_off_t         *offset,
      filldir_t         filldir)
{
      xfs_dir2_block_t  *block;           /* directory block structure */
      xfs_dabuf_t       *bp;        /* buffer for block */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_dir2_data_entry_t   *dep;       /* block data entry */
      xfs_dir2_data_unused_t  *dup;       /* block unused entry */
      char              *endptr;    /* end of the data entries */
      int               error;            /* error return value */
      xfs_mount_t       *mp;        /* filesystem mount point */
      char              *ptr;       /* current data entry */
      int               wantoff;    /* starting block offset */
      xfs_ino_t         ino;
      xfs_off_t         cook;

      mp = dp->i_mount;
      /*
       * If the block number in the offset is out of range, we're done.
       */
      if (xfs_dir2_dataptr_to_db(mp, *offset) > mp->m_dirdatablk) {
            return 0;
      }
      /*
       * Can't read the block, give up, else get dabuf in bp.
       */
      error = xfs_da_read_buf(NULL, dp, mp->m_dirdatablk, -1,
                        &bp, XFS_DATA_FORK);
      if (error)
            return error;

      ASSERT(bp != NULL);
      /*
       * Extract the byte offset we start at from the seek pointer.
       * We'll skip entries before this.
       */
      wantoff = xfs_dir2_dataptr_to_off(mp, *offset);
      block = bp->data;
      xfs_dir2_data_check(dp, bp);
      /*
       * Set up values for the loop.
       */
      btp = xfs_dir2_block_tail_p(mp, block);
      ptr = (char *)block->u;
      endptr = (char *)xfs_dir2_block_leaf_p(btp);

      /*
       * Loop over the data portion of the block.
       * Each object is a real entry (dep) or an unused one (dup).
       */
      while (ptr < endptr) {
            dup = (xfs_dir2_data_unused_t *)ptr;
            /*
             * Unused, skip it.
             */
            if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
                  ptr += be16_to_cpu(dup->length);
                  continue;
            }

            dep = (xfs_dir2_data_entry_t *)ptr;

            /*
             * Bump pointer for the next iteration.
             */
            ptr += xfs_dir2_data_entsize(dep->namelen);
            /*
             * The entry is before the desired starting point, skip it.
             */
            if ((char *)dep - (char *)block < wantoff)
                  continue;

            cook = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
                                  (char *)dep - (char *)block);
            ino = be64_to_cpu(dep->inumber);
#if XFS_BIG_INUMS
            ino += mp->m_inoadd;
#endif

            /*
             * If it didn't fit, set the final offset to here & return.
             */
            if (filldir(dirent, dep->name, dep->namelen, cook,
                      ino, DT_UNKNOWN)) {
                  *offset = cook;
                  xfs_da_brelse(NULL, bp);
                  return 0;
            }
      }

      /*
       * Reached the end of the block.
       * Set the offset to a non-existent block 1 and return.
       */
      *offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0);
      xfs_da_brelse(NULL, bp);
      return 0;
}

/*
 * Log leaf entries from the block.
 */
static void
xfs_dir2_block_log_leaf(
      xfs_trans_t       *tp,        /* transaction structure */
      xfs_dabuf_t       *bp,        /* block buffer */
      int               first,            /* index of first logged leaf */
      int               last)       /* index of last logged leaf */
{
      xfs_dir2_block_t  *block;           /* directory block structure */
      xfs_dir2_leaf_entry_t   *blp;       /* block leaf entries */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_mount_t       *mp;        /* filesystem mount point */

      mp = tp->t_mountp;
      block = bp->data;
      btp = xfs_dir2_block_tail_p(mp, block);
      blp = xfs_dir2_block_leaf_p(btp);
      xfs_da_log_buf(tp, bp, (uint)((char *)&blp[first] - (char *)block),
            (uint)((char *)&blp[last + 1] - (char *)block - 1));
}

/*
 * Log the block tail.
 */
static void
xfs_dir2_block_log_tail(
      xfs_trans_t       *tp,        /* transaction structure */
      xfs_dabuf_t       *bp)        /* block buffer */
{
      xfs_dir2_block_t  *block;           /* directory block structure */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_mount_t       *mp;        /* filesystem mount point */

      mp = tp->t_mountp;
      block = bp->data;
      btp = xfs_dir2_block_tail_p(mp, block);
      xfs_da_log_buf(tp, bp, (uint)((char *)btp - (char *)block),
            (uint)((char *)(btp + 1) - (char *)block - 1));
}

/*
 * Look up an entry in the block.  This is the external routine,
 * xfs_dir2_block_lookup_int does the real work.
 */
int                                 /* error */
xfs_dir2_block_lookup(
      xfs_da_args_t           *args)            /* dir lookup arguments */
{
      xfs_dir2_block_t  *block;           /* block structure */
      xfs_dir2_leaf_entry_t   *blp;       /* block leaf entries */
      xfs_dabuf_t       *bp;        /* block buffer */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_dir2_data_entry_t   *dep;       /* block data entry */
      xfs_inode_t       *dp;        /* incore inode */
      int               ent;        /* entry index */
      int               error;            /* error return value */
      xfs_mount_t       *mp;        /* filesystem mount point */

      xfs_dir2_trace_args("block_lookup", args);
      /*
       * Get the buffer, look up the entry.
       * If not found (ENOENT) then return, have no buffer.
       */
      if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent)))
            return error;
      dp = args->dp;
      mp = dp->i_mount;
      block = bp->data;
      xfs_dir2_data_check(dp, bp);
      btp = xfs_dir2_block_tail_p(mp, block);
      blp = xfs_dir2_block_leaf_p(btp);
      /*
       * Get the offset from the leaf entry, to point to the data.
       */
      dep = (xfs_dir2_data_entry_t *)
            ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
      /*
       * Fill in inode number, release the block.
       */
      args->inumber = be64_to_cpu(dep->inumber);
      xfs_da_brelse(args->trans, bp);
      return XFS_ERROR(EEXIST);
}

/*
 * Internal block lookup routine.
 */
static int                          /* error */
xfs_dir2_block_lookup_int(
      xfs_da_args_t           *args,            /* dir lookup arguments */
      xfs_dabuf_t       **bpp,            /* returned block buffer */
      int               *entno)           /* returned entry number */
{
      xfs_dir2_dataptr_t      addr;       /* data entry address */
      xfs_dir2_block_t  *block;           /* block structure */
      xfs_dir2_leaf_entry_t   *blp;       /* block leaf entries */
      xfs_dabuf_t       *bp;        /* block buffer */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_dir2_data_entry_t   *dep;       /* block data entry */
      xfs_inode_t       *dp;        /* incore inode */
      int               error;            /* error return value */
      xfs_dahash_t            hash;       /* found hash value */
      int               high;       /* binary search high index */
      int               low;        /* binary search low index */
      int               mid;        /* binary search current idx */
      xfs_mount_t       *mp;        /* filesystem mount point */
      xfs_trans_t       *tp;        /* transaction pointer */

      dp = args->dp;
      tp = args->trans;
      mp = dp->i_mount;
      /*
       * Read the buffer, return error if we can't get it.
       */
      if ((error =
          xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &bp, XFS_DATA_FORK))) {
            return error;
      }
      ASSERT(bp != NULL);
      block = bp->data;
      xfs_dir2_data_check(dp, bp);
      btp = xfs_dir2_block_tail_p(mp, block);
      blp = xfs_dir2_block_leaf_p(btp);
      /*
       * Loop doing a binary search for our hash value.
       * Find our entry, ENOENT if it's not there.
       */
      for (low = 0, high = be32_to_cpu(btp->count) - 1; ; ) {
            ASSERT(low <= high);
            mid = (low + high) >> 1;
            if ((hash = be32_to_cpu(blp[mid].hashval)) == args->hashval)
                  break;
            if (hash < args->hashval)
                  low = mid + 1;
            else
                  high = mid - 1;
            if (low > high) {
                  ASSERT(args->oknoent);
                  xfs_da_brelse(tp, bp);
                  return XFS_ERROR(ENOENT);
            }
      }
      /*
       * Back up to the first one with the right hash value.
       */
      while (mid > 0 && be32_to_cpu(blp[mid - 1].hashval) == args->hashval) {
            mid--;
      }
      /*
       * Now loop forward through all the entries with the
       * right hash value looking for our name.
       */
      do {
            if ((addr = be32_to_cpu(blp[mid].address)) == XFS_DIR2_NULL_DATAPTR)
                  continue;
            /*
             * Get pointer to the entry from the leaf.
             */
            dep = (xfs_dir2_data_entry_t *)
                  ((char *)block + xfs_dir2_dataptr_to_off(mp, addr));
            /*
             * Compare, if it's right give back buffer & entry number.
             */
            if (dep->namelen == args->namelen &&
                dep->name[0] == args->name[0] &&
                memcmp(dep->name, args->name, args->namelen) == 0) {
                  *bpp = bp;
                  *entno = mid;
                  return 0;
            }
      } while (++mid < be32_to_cpu(btp->count) && be32_to_cpu(blp[mid].hashval) == hash);
      /*
       * No match, release the buffer and return ENOENT.
       */
      ASSERT(args->oknoent);
      xfs_da_brelse(tp, bp);
      return XFS_ERROR(ENOENT);
}

/*
 * Remove an entry from a block format directory.
 * If that makes the block small enough to fit in shortform, transform it.
 */
int                                 /* error */
xfs_dir2_block_removename(
      xfs_da_args_t           *args)            /* directory operation args */
{
      xfs_dir2_block_t  *block;           /* block structure */
      xfs_dir2_leaf_entry_t   *blp;       /* block leaf pointer */
      xfs_dabuf_t       *bp;        /* block buffer */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_dir2_data_entry_t   *dep;       /* block data entry */
      xfs_inode_t       *dp;        /* incore inode */
      int               ent;        /* block leaf entry index */
      int               error;            /* error return value */
      xfs_mount_t       *mp;        /* filesystem mount point */
      int               needlog;    /* need to log block header */
      int               needscan;   /* need to fixup bestfree */
      xfs_dir2_sf_hdr_t sfh;        /* shortform header */
      int               size;       /* shortform size */
      xfs_trans_t       *tp;        /* transaction pointer */

      xfs_dir2_trace_args("block_removename", args);
      /*
       * Look up the entry in the block.  Gets the buffer and entry index.
       * It will always be there, the vnodeops level does a lookup first.
       */
      if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent))) {
            return error;
      }
      dp = args->dp;
      tp = args->trans;
      mp = dp->i_mount;
      block = bp->data;
      btp = xfs_dir2_block_tail_p(mp, block);
      blp = xfs_dir2_block_leaf_p(btp);
      /*
       * Point to the data entry using the leaf entry.
       */
      dep = (xfs_dir2_data_entry_t *)
            ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
      /*
       * Mark the data entry's space free.
       */
      needlog = needscan = 0;
      xfs_dir2_data_make_free(tp, bp,
            (xfs_dir2_data_aoff_t)((char *)dep - (char *)block),
            xfs_dir2_data_entsize(dep->namelen), &needlog, &needscan);
      /*
       * Fix up the block tail.
       */
      be32_add(&btp->stale, 1);
      xfs_dir2_block_log_tail(tp, bp);
      /*
       * Remove the leaf entry by marking it stale.
       */
      blp[ent].address = cpu_to_be32(XFS_DIR2_NULL_DATAPTR);
      xfs_dir2_block_log_leaf(tp, bp, ent, ent);
      /*
       * Fix up bestfree, log the header if necessary.
       */
      if (needscan)
            xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog);
      if (needlog)
            xfs_dir2_data_log_header(tp, bp);
      xfs_dir2_data_check(dp, bp);
      /*
       * See if the size as a shortform is good enough.
       */
      if ((size = xfs_dir2_block_sfsize(dp, block, &sfh)) >
          XFS_IFORK_DSIZE(dp)) {
            xfs_da_buf_done(bp);
            return 0;
      }
      /*
       * If it works, do the conversion.
       */
      return xfs_dir2_block_to_sf(args, bp, size, &sfh);
}

/*
 * Replace an entry in a V2 block directory.
 * Change the inode number to the new value.
 */
int                                 /* error */
xfs_dir2_block_replace(
      xfs_da_args_t           *args)            /* directory operation args */
{
      xfs_dir2_block_t  *block;           /* block structure */
      xfs_dir2_leaf_entry_t   *blp;       /* block leaf entries */
      xfs_dabuf_t       *bp;        /* block buffer */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_dir2_data_entry_t   *dep;       /* block data entry */
      xfs_inode_t       *dp;        /* incore inode */
      int               ent;        /* leaf entry index */
      int               error;            /* error return value */
      xfs_mount_t       *mp;        /* filesystem mount point */

      xfs_dir2_trace_args("block_replace", args);
      /*
       * Lookup the entry in the directory.  Get buffer and entry index.
       * This will always succeed since the caller has already done a lookup.
       */
      if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent))) {
            return error;
      }
      dp = args->dp;
      mp = dp->i_mount;
      block = bp->data;
      btp = xfs_dir2_block_tail_p(mp, block);
      blp = xfs_dir2_block_leaf_p(btp);
      /*
       * Point to the data entry we need to change.
       */
      dep = (xfs_dir2_data_entry_t *)
            ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
      ASSERT(be64_to_cpu(dep->inumber) != args->inumber);
      /*
       * Change the inode number to the new value.
       */
      dep->inumber = cpu_to_be64(args->inumber);
      xfs_dir2_data_log_entry(args->trans, bp, dep);
      xfs_dir2_data_check(dp, bp);
      xfs_da_buf_done(bp);
      return 0;
}

/*
 * Qsort comparison routine for the block leaf entries.
 */
static int                          /* sort order */
xfs_dir2_block_sort(
      const void              *a,   /* first leaf entry */
      const void              *b)   /* second leaf entry */
{
      const xfs_dir2_leaf_entry_t   *la;  /* first leaf entry */
      const xfs_dir2_leaf_entry_t   *lb;  /* second leaf entry */

      la = a;
      lb = b;
      return be32_to_cpu(la->hashval) < be32_to_cpu(lb->hashval) ? -1 :
            (be32_to_cpu(la->hashval) > be32_to_cpu(lb->hashval) ? 1 : 0);
}

/*
 * Convert a V2 leaf directory to a V2 block directory if possible.
 */
int                                 /* error */
xfs_dir2_leaf_to_block(
      xfs_da_args_t           *args,            /* operation arguments */
      xfs_dabuf_t       *lbp,       /* leaf buffer */
      xfs_dabuf_t       *dbp)       /* data buffer */
{
      __be16                  *bestsp;    /* leaf bests table */
      xfs_dir2_block_t  *block;           /* block structure */
      xfs_dir2_block_tail_t   *btp;       /* block tail */
      xfs_inode_t       *dp;        /* incore directory inode */
      xfs_dir2_data_unused_t  *dup;       /* unused data entry */
      int               error;            /* error return value */
      int               from;       /* leaf from index */
      xfs_dir2_leaf_t         *leaf;            /* leaf structure */
      xfs_dir2_leaf_entry_t   *lep;       /* leaf entry */
      xfs_dir2_leaf_tail_t    *ltp;       /* leaf tail structure */
      xfs_mount_t       *mp;        /* file system mount point */
      int               needlog;    /* need to log data header */
      int               needscan;   /* need to scan for bestfree */
      xfs_dir2_sf_hdr_t sfh;        /* shortform header */
      int               size;       /* bytes used */
      __be16                  *tagp;            /* end of entry (tag) */
      int               to;         /* block/leaf to index */
      xfs_trans_t       *tp;        /* transaction pointer */

      xfs_dir2_trace_args_bb("leaf_to_block", args, lbp, dbp);
      dp = args->dp;
      tp = args->trans;
      mp = dp->i_mount;
      leaf = lbp->data;
      ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAF1_MAGIC);
      ltp = xfs_dir2_leaf_tail_p(mp, leaf);
      /*
       * If there are data blocks other than the first one, take this
       * opportunity to remove trailing empty data blocks that may have
       * been left behind during no-space-reservation operations.
       * These will show up in the leaf bests table.
       */
      while (dp->i_d.di_size > mp->m_dirblksize) {
            bestsp = xfs_dir2_leaf_bests_p(ltp);
            if (be16_to_cpu(bestsp[be32_to_cpu(ltp->bestcount) - 1]) ==
                mp->m_dirblksize - (uint)sizeof(block->hdr)) {
                  if ((error =
                      xfs_dir2_leaf_trim_data(args, lbp,
                            (xfs_dir2_db_t)(be32_to_cpu(ltp->bestcount) - 1))))
                        goto out;
            } else {
                  error = 0;
                  goto out;
            }
      }
      /*
       * Read the data block if we don't already have it, give up if it fails.
       */
      if (dbp == NULL &&
          (error = xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &dbp,
                XFS_DATA_FORK))) {
            goto out;
      }
      block = dbp->data;
      ASSERT(be32_to_cpu(block->hdr.magic) == XFS_DIR2_DATA_MAGIC);
      /*
       * Size of the "leaf" area in the block.
       */
      size = (uint)sizeof(block->tail) +
             (uint)sizeof(*lep) * (be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale));
      /*
       * Look at the last data entry.
       */
      tagp = (__be16 *)((char *)block + mp->m_dirblksize) - 1;
      dup = (xfs_dir2_data_unused_t *)((char *)block + be16_to_cpu(*tagp));
      /*
       * If it's not free or is too short we can't do it.
       */
      if (be16_to_cpu(dup->freetag) != XFS_DIR2_DATA_FREE_TAG ||
          be16_to_cpu(dup->length) < size) {
            error = 0;
            goto out;
      }
      /*
       * Start converting it to block form.
       */
      block->hdr.magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
      needlog = 1;
      needscan = 0;
      /*
       * Use up the space at the end of the block (blp/btp).
       */
      xfs_dir2_data_use_free(tp, dbp, dup, mp->m_dirblksize - size, size,
            &needlog, &needscan);
      /*
       * Initialize the block tail.
       */
      btp = xfs_dir2_block_tail_p(mp, block);
      btp->count = cpu_to_be32(be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale));
      btp->stale = 0;
      xfs_dir2_block_log_tail(tp, dbp);
      /*
       * Initialize the block leaf area.  We compact out stale entries.
       */
      lep = xfs_dir2_block_leaf_p(btp);
      for (from = to = 0; from < be16_to_cpu(leaf->hdr.count); from++) {
            if (be32_to_cpu(leaf->ents[from].address) == XFS_DIR2_NULL_DATAPTR)
                  continue;
            lep[to++] = leaf->ents[from];
      }
      ASSERT(to == be32_to_cpu(btp->count));
      xfs_dir2_block_log_leaf(tp, dbp, 0, be32_to_cpu(btp->count) - 1);
      /*
       * Scan the bestfree if we need it and log the data block header.
       */
      if (needscan)
            xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog);
      if (needlog)
            xfs_dir2_data_log_header(tp, dbp);
      /*
       * Pitch the old leaf block.
       */
      error = xfs_da_shrink_inode(args, mp->m_dirleafblk, lbp);
      lbp = NULL;
      if (error) {
            goto out;
      }
      /*
       * Now see if the resulting block can be shrunken to shortform.
       */
      if ((size = xfs_dir2_block_sfsize(dp, block, &sfh)) >
          XFS_IFORK_DSIZE(dp)) {
            error = 0;
            goto out;
      }
      return xfs_dir2_block_to_sf(args, dbp, size, &sfh);
out:
      if (lbp)
            xfs_da_buf_done(lbp);
      if (dbp)
            xfs_da_buf_done(dbp);
      return error;
}

/*
 * Convert the shortform directory to block form.
 */
int                                 /* error */
xfs_dir2_sf_to_block(
      xfs_da_args_t           *args)            /* operation arguments */
{
      xfs_dir2_db_t           blkno;            /* dir-relative block # (0) */
      xfs_dir2_block_t  *block;           /* block structure */
      xfs_dir2_leaf_entry_t   *blp;       /* block leaf entries */
      xfs_dabuf_t       *bp;        /* block buffer */
      xfs_dir2_block_tail_t   *btp;       /* block tail pointer */
      char              *buf;       /* sf buffer */
      int               buf_len;
      xfs_dir2_data_entry_t   *dep;       /* data entry pointer */
      xfs_inode_t       *dp;        /* incore directory inode */
      int               dummy;            /* trash */
      xfs_dir2_data_unused_t  *dup;       /* unused entry pointer */
      int               endoffset;  /* end of data objects */
      int               error;            /* error return value */
      int               i;          /* index */
      xfs_mount_t       *mp;        /* filesystem mount point */
      int               needlog;    /* need to log block header */
      int               needscan;   /* need to scan block freespc */
      int               newoffset;  /* offset from current entry */
      int               offset;           /* target block offset */
      xfs_dir2_sf_entry_t     *sfep;            /* sf entry pointer */
      xfs_dir2_sf_t           *sfp;       /* shortform structure */
      __be16                  *tagp;            /* end of data entry */
      xfs_trans_t       *tp;        /* transaction pointer */

      xfs_dir2_trace_args("sf_to_block", args);
      dp = args->dp;
      tp = args->trans;
      mp = dp->i_mount;
      ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
      /*
       * Bomb out if the shortform directory is way too short.
       */
      if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
            ASSERT(XFS_FORCED_SHUTDOWN(mp));
            return XFS_ERROR(EIO);
      }
      ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
      ASSERT(dp->i_df.if_u1.if_data != NULL);
      sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
      ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->hdr.i8count));
      /*
       * Copy the directory into the stack buffer.
       * Then pitch the incore inode data so we can make extents.
       */

      buf_len = dp->i_df.if_bytes;
      buf = kmem_alloc(dp->i_df.if_bytes, KM_SLEEP);

      memcpy(buf, sfp, dp->i_df.if_bytes);
      xfs_idata_realloc(dp, -dp->i_df.if_bytes, XFS_DATA_FORK);
      dp->i_d.di_size = 0;
      xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
      /*
       * Reset pointer - old sfp is gone.
       */
      sfp = (xfs_dir2_sf_t *)buf;
      /*
       * Add block 0 to the inode.
       */
      error = xfs_dir2_grow_inode(args, XFS_DIR2_DATA_SPACE, &blkno);
      if (error) {
            kmem_free(buf, buf_len);
            return error;
      }
      /*
       * Initialize the data block.
       */
      error = xfs_dir2_data_init(args, blkno, &bp);
      if (error) {
            kmem_free(buf, buf_len);
            return error;
      }
      block = bp->data;
      block->hdr.magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
      /*
       * Compute size of block "tail" area.
       */
      i = (uint)sizeof(*btp) +
          (sfp->hdr.count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t);
      /*
       * The whole thing is initialized to free by the init routine.
       * Say we're using the leaf and tail area.
       */
      dup = (xfs_dir2_data_unused_t *)block->u;
      needlog = needscan = 0;
      xfs_dir2_data_use_free(tp, bp, dup, mp->m_dirblksize - i, i, &needlog,
            &needscan);
      ASSERT(needscan == 0);
      /*
       * Fill in the tail.
       */
      btp = xfs_dir2_block_tail_p(mp, block);
      btp->count = cpu_to_be32(sfp->hdr.count + 2);   /* ., .. */
      btp->stale = 0;
      blp = xfs_dir2_block_leaf_p(btp);
      endoffset = (uint)((char *)blp - (char *)block);
      /*
       * Remove the freespace, we'll manage it.
       */
      xfs_dir2_data_use_free(tp, bp, dup,
            (xfs_dir2_data_aoff_t)((char *)dup - (char *)block),
            be16_to_cpu(dup->length), &needlog, &needscan);
      /*
       * Create entry for .
       */
      dep = (xfs_dir2_data_entry_t *)
            ((char *)block + XFS_DIR2_DATA_DOT_OFFSET);
      dep->inumber = cpu_to_be64(dp->i_ino);
      dep->namelen = 1;
      dep->name[0] = '.';
      tagp = xfs_dir2_data_entry_tag_p(dep);
      *tagp = cpu_to_be16((char *)dep - (char *)block);
      xfs_dir2_data_log_entry(tp, bp, dep);
      blp[0].hashval = cpu_to_be32(xfs_dir_hash_dot);
      blp[0].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
                        (char *)dep - (char *)block));
      /*
       * Create entry for ..
       */
      dep = (xfs_dir2_data_entry_t *)
            ((char *)block + XFS_DIR2_DATA_DOTDOT_OFFSET);
      dep->inumber = cpu_to_be64(xfs_dir2_sf_get_inumber(sfp, &sfp->hdr.parent));
      dep->namelen = 2;
      dep->name[0] = dep->name[1] = '.';
      tagp = xfs_dir2_data_entry_tag_p(dep);
      *tagp = cpu_to_be16((char *)dep - (char *)block);
      xfs_dir2_data_log_entry(tp, bp, dep);
      blp[1].hashval = cpu_to_be32(xfs_dir_hash_dotdot);
      blp[1].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
                        (char *)dep - (char *)block));
      offset = XFS_DIR2_DATA_FIRST_OFFSET;
      /*
       * Loop over existing entries, stuff them in.
       */
      if ((i = 0) == sfp->hdr.count)
            sfep = NULL;
      else
            sfep = xfs_dir2_sf_firstentry(sfp);
      /*
       * Need to preserve the existing offset values in the sf directory.
       * Insert holes (unused entries) where necessary.
       */
      while (offset < endoffset) {
            /*
             * sfep is null when we reach the end of the list.
             */
            if (sfep == NULL)
                  newoffset = endoffset;
            else
                  newoffset = xfs_dir2_sf_get_offset(sfep);
            /*
             * There should be a hole here, make one.
             */
            if (offset < newoffset) {
                  dup = (xfs_dir2_data_unused_t *)
                        ((char *)block + offset);
                  dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
                  dup->length = cpu_to_be16(newoffset - offset);
                  *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16(
                        ((char *)dup - (char *)block));
                  xfs_dir2_data_log_unused(tp, bp, dup);
                  (void)xfs_dir2_data_freeinsert((xfs_dir2_data_t *)block,
                        dup, &dummy);
                  offset += be16_to_cpu(dup->length);
                  continue;
            }
            /*
             * Copy a real entry.
             */
            dep = (xfs_dir2_data_entry_t *)((char *)block + newoffset);
            dep->inumber = cpu_to_be64(xfs_dir2_sf_get_inumber(sfp,
                        xfs_dir2_sf_inumberp(sfep)));
            dep->namelen = sfep->namelen;
            memcpy(dep->name, sfep->name, dep->namelen);
            tagp = xfs_dir2_data_entry_tag_p(dep);
            *tagp = cpu_to_be16((char *)dep - (char *)block);
            xfs_dir2_data_log_entry(tp, bp, dep);
            blp[2 + i].hashval = cpu_to_be32(xfs_da_hashname(
                              (char *)sfep->name, sfep->namelen));
            blp[2 + i].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
                                     (char *)dep - (char *)block));
            offset = (int)((char *)(tagp + 1) - (char *)block);
            if (++i == sfp->hdr.count)
                  sfep = NULL;
            else
                  sfep = xfs_dir2_sf_nextentry(sfp, sfep);
      }
      /* Done with the temporary buffer */
      kmem_free(buf, buf_len);
      /*
       * Sort the leaf entries by hash value.
       */
      xfs_sort(blp, be32_to_cpu(btp->count), sizeof(*blp), xfs_dir2_block_sort);
      /*
       * Log the leaf entry area and tail.
       * Already logged the header in data_init, ignore needlog.
       */
      ASSERT(needscan == 0);
      xfs_dir2_block_log_leaf(tp, bp, 0, be32_to_cpu(btp->count) - 1);
      xfs_dir2_block_log_tail(tp, bp);
      xfs_dir2_data_check(dp, bp);
      xfs_da_buf_done(bp);
      return 0;
}

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