Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / xfs / libxfs / xfs_dir2_data.c
diff --git a/kernel/fs/xfs/libxfs/xfs_dir2_data.c b/kernel/fs/xfs/libxfs/xfs_dir2_data.c
new file mode 100644 (file)
index 0000000..de1ea16
--- /dev/null
@@ -0,0 +1,1049 @@
+/*
+ * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2013 Red Hat, 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_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_inode.h"
+#include "xfs_dir2.h"
+#include "xfs_dir2_priv.h"
+#include "xfs_error.h"
+#include "xfs_trans.h"
+#include "xfs_buf_item.h"
+#include "xfs_cksum.h"
+
+/*
+ * Check the consistency of the data block.
+ * The input can also be a block-format directory.
+ * Return 0 is the buffer is good, otherwise an error.
+ */
+int
+__xfs_dir3_data_check(
+       struct xfs_inode        *dp,            /* incore inode pointer */
+       struct xfs_buf          *bp)            /* data block's buffer */
+{
+       xfs_dir2_dataptr_t      addr;           /* addr for leaf lookup */
+       xfs_dir2_data_free_t    *bf;            /* bestfree table */
+       xfs_dir2_block_tail_t   *btp=NULL;      /* block tail */
+       int                     count;          /* count of entries found */
+       xfs_dir2_data_hdr_t     *hdr;           /* data block header */
+       xfs_dir2_data_entry_t   *dep;           /* data entry */
+       xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
+       xfs_dir2_data_unused_t  *dup;           /* unused entry */
+       char                    *endp;          /* end of useful data */
+       int                     freeseen;       /* mask of bestfrees seen */
+       xfs_dahash_t            hash;           /* hash of current name */
+       int                     i;              /* leaf index */
+       int                     lastfree;       /* last entry was unused */
+       xfs_dir2_leaf_entry_t   *lep=NULL;      /* block leaf entries */
+       xfs_mount_t             *mp;            /* filesystem mount point */
+       char                    *p;             /* current data position */
+       int                     stale;          /* count of stale leaves */
+       struct xfs_name         name;
+       const struct xfs_dir_ops *ops;
+       struct xfs_da_geometry  *geo;
+
+       mp = bp->b_target->bt_mount;
+       geo = mp->m_dir_geo;
+
+       /*
+        * We can be passed a null dp here from a verifier, so we need to go the
+        * hard way to get them.
+        */
+       ops = xfs_dir_get_ops(mp, dp);
+
+       hdr = bp->b_addr;
+       p = (char *)ops->data_entry_p(hdr);
+
+       switch (hdr->magic) {
+       case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
+       case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
+               btp = xfs_dir2_block_tail_p(geo, hdr);
+               lep = xfs_dir2_block_leaf_p(btp);
+               endp = (char *)lep;
+
+               /*
+                * The number of leaf entries is limited by the size of the
+                * block and the amount of space used by the data entries.
+                * We don't know how much space is used by the data entries yet,
+                * so just ensure that the count falls somewhere inside the
+                * block right now.
+                */
+               XFS_WANT_CORRUPTED_RETURN(mp, be32_to_cpu(btp->count) <
+                       ((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry));
+               break;
+       case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
+       case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
+               endp = (char *)hdr + geo->blksize;
+               break;
+       default:
+               XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
+               return -EFSCORRUPTED;
+       }
+
+       /*
+        * Account for zero bestfree entries.
+        */
+       bf = ops->data_bestfree_p(hdr);
+       count = lastfree = freeseen = 0;
+       if (!bf[0].length) {
+               XFS_WANT_CORRUPTED_RETURN(mp, !bf[0].offset);
+               freeseen |= 1 << 0;
+       }
+       if (!bf[1].length) {
+               XFS_WANT_CORRUPTED_RETURN(mp, !bf[1].offset);
+               freeseen |= 1 << 1;
+       }
+       if (!bf[2].length) {
+               XFS_WANT_CORRUPTED_RETURN(mp, !bf[2].offset);
+               freeseen |= 1 << 2;
+       }
+
+       XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[0].length) >=
+                                               be16_to_cpu(bf[1].length));
+       XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[1].length) >=
+                                               be16_to_cpu(bf[2].length));
+       /*
+        * Loop over the data/unused entries.
+        */
+       while (p < endp) {
+               dup = (xfs_dir2_data_unused_t *)p;
+               /*
+                * If it's unused, look for the space in the bestfree table.
+                * If we find it, account for that, else make sure it
+                * doesn't need to be there.
+                */
+               if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
+                       XFS_WANT_CORRUPTED_RETURN(mp, lastfree == 0);
+                       XFS_WANT_CORRUPTED_RETURN(mp,
+                               be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
+                                              (char *)dup - (char *)hdr);
+                       dfp = xfs_dir2_data_freefind(hdr, bf, dup);
+                       if (dfp) {
+                               i = (int)(dfp - bf);
+                               XFS_WANT_CORRUPTED_RETURN(mp,
+                                       (freeseen & (1 << i)) == 0);
+                               freeseen |= 1 << i;
+                       } else {
+                               XFS_WANT_CORRUPTED_RETURN(mp,
+                                       be16_to_cpu(dup->length) <=
+                                               be16_to_cpu(bf[2].length));
+                       }
+                       p += be16_to_cpu(dup->length);
+                       lastfree = 1;
+                       continue;
+               }
+               /*
+                * It's a real entry.  Validate the fields.
+                * If this is a block directory then make sure it's
+                * in the leaf section of the block.
+                * The linear search is crude but this is DEBUG code.
+                */
+               dep = (xfs_dir2_data_entry_t *)p;
+               XFS_WANT_CORRUPTED_RETURN(mp, dep->namelen != 0);
+               XFS_WANT_CORRUPTED_RETURN(mp,
+                       !xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
+               XFS_WANT_CORRUPTED_RETURN(mp,
+                       be16_to_cpu(*ops->data_entry_tag_p(dep)) ==
+                                              (char *)dep - (char *)hdr);
+               XFS_WANT_CORRUPTED_RETURN(mp,
+                               ops->data_get_ftype(dep) < XFS_DIR3_FT_MAX);
+               count++;
+               lastfree = 0;
+               if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+                   hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
+                       addr = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
+                                               (xfs_dir2_data_aoff_t)
+                                               ((char *)dep - (char *)hdr));
+                       name.name = dep->name;
+                       name.len = dep->namelen;
+                       hash = mp->m_dirnameops->hashname(&name);
+                       for (i = 0; i < be32_to_cpu(btp->count); i++) {
+                               if (be32_to_cpu(lep[i].address) == addr &&
+                                   be32_to_cpu(lep[i].hashval) == hash)
+                                       break;
+                       }
+                       XFS_WANT_CORRUPTED_RETURN(mp,
+                                                 i < be32_to_cpu(btp->count));
+               }
+               p += ops->data_entsize(dep->namelen);
+       }
+       /*
+        * Need to have seen all the entries and all the bestfree slots.
+        */
+       XFS_WANT_CORRUPTED_RETURN(mp, freeseen == 7);
+       if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+           hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
+               for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
+                       if (lep[i].address ==
+                           cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
+                               stale++;
+                       if (i > 0)
+                               XFS_WANT_CORRUPTED_RETURN(mp,
+                                       be32_to_cpu(lep[i].hashval) >=
+                                               be32_to_cpu(lep[i - 1].hashval));
+               }
+               XFS_WANT_CORRUPTED_RETURN(mp, count ==
+                       be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
+               XFS_WANT_CORRUPTED_RETURN(mp, stale == be32_to_cpu(btp->stale));
+       }
+       return 0;
+}
+
+static bool
+xfs_dir3_data_verify(
+       struct xfs_buf          *bp)
+{
+       struct xfs_mount        *mp = bp->b_target->bt_mount;
+       struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
+
+       if (xfs_sb_version_hascrc(&mp->m_sb)) {
+               if (hdr3->magic != cpu_to_be32(XFS_DIR3_DATA_MAGIC))
+                       return false;
+               if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_uuid))
+                       return false;
+               if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
+                       return false;
+       } else {
+               if (hdr3->magic != cpu_to_be32(XFS_DIR2_DATA_MAGIC))
+                       return false;
+       }
+       if (__xfs_dir3_data_check(NULL, bp))
+               return false;
+       return true;
+}
+
+/*
+ * Readahead of the first block of the directory when it is opened is completely
+ * oblivious to the format of the directory. Hence we can either get a block
+ * format buffer or a data format buffer on readahead.
+ */
+static void
+xfs_dir3_data_reada_verify(
+       struct xfs_buf          *bp)
+{
+       struct xfs_dir2_data_hdr *hdr = bp->b_addr;
+
+       switch (hdr->magic) {
+       case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
+       case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
+               bp->b_ops = &xfs_dir3_block_buf_ops;
+               bp->b_ops->verify_read(bp);
+               return;
+       case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
+       case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
+               xfs_dir3_data_verify(bp);
+               return;
+       default:
+               xfs_buf_ioerror(bp, -EFSCORRUPTED);
+               xfs_verifier_error(bp);
+               break;
+       }
+}
+
+static void
+xfs_dir3_data_read_verify(
+       struct xfs_buf  *bp)
+{
+       struct xfs_mount        *mp = bp->b_target->bt_mount;
+
+       if (xfs_sb_version_hascrc(&mp->m_sb) &&
+            !xfs_buf_verify_cksum(bp, XFS_DIR3_DATA_CRC_OFF))
+                xfs_buf_ioerror(bp, -EFSBADCRC);
+       else if (!xfs_dir3_data_verify(bp))
+               xfs_buf_ioerror(bp, -EFSCORRUPTED);
+
+       if (bp->b_error)
+               xfs_verifier_error(bp);
+}
+
+static void
+xfs_dir3_data_write_verify(
+       struct xfs_buf  *bp)
+{
+       struct xfs_mount        *mp = bp->b_target->bt_mount;
+       struct xfs_buf_log_item *bip = bp->b_fspriv;
+       struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
+
+       if (!xfs_dir3_data_verify(bp)) {
+               xfs_buf_ioerror(bp, -EFSCORRUPTED);
+               xfs_verifier_error(bp);
+               return;
+       }
+
+       if (!xfs_sb_version_hascrc(&mp->m_sb))
+               return;
+
+       if (bip)
+               hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);
+
+       xfs_buf_update_cksum(bp, XFS_DIR3_DATA_CRC_OFF);
+}
+
+const struct xfs_buf_ops xfs_dir3_data_buf_ops = {
+       .verify_read = xfs_dir3_data_read_verify,
+       .verify_write = xfs_dir3_data_write_verify,
+};
+
+static const struct xfs_buf_ops xfs_dir3_data_reada_buf_ops = {
+       .verify_read = xfs_dir3_data_reada_verify,
+       .verify_write = xfs_dir3_data_write_verify,
+};
+
+
+int
+xfs_dir3_data_read(
+       struct xfs_trans        *tp,
+       struct xfs_inode        *dp,
+       xfs_dablk_t             bno,
+       xfs_daddr_t             mapped_bno,
+       struct xfs_buf          **bpp)
+{
+       int                     err;
+
+       err = xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
+                               XFS_DATA_FORK, &xfs_dir3_data_buf_ops);
+       if (!err && tp)
+               xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_DATA_BUF);
+       return err;
+}
+
+int
+xfs_dir3_data_readahead(
+       struct xfs_inode        *dp,
+       xfs_dablk_t             bno,
+       xfs_daddr_t             mapped_bno)
+{
+       return xfs_da_reada_buf(dp, bno, mapped_bno,
+                               XFS_DATA_FORK, &xfs_dir3_data_reada_buf_ops);
+}
+
+/*
+ * Given a data block and an unused entry from that block,
+ * return the bestfree entry if any that corresponds to it.
+ */
+xfs_dir2_data_free_t *
+xfs_dir2_data_freefind(
+       struct xfs_dir2_data_hdr *hdr,          /* data block header */
+       struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
+       struct xfs_dir2_data_unused *dup)       /* unused space */
+{
+       xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
+       xfs_dir2_data_aoff_t    off;            /* offset value needed */
+#ifdef DEBUG
+       int                     matched;        /* matched the value */
+       int                     seenzero;       /* saw a 0 bestfree entry */
+#endif
+
+       off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
+
+#ifdef DEBUG
+       /*
+        * Validate some consistency in the bestfree table.
+        * Check order, non-overlapping entries, and if we find the
+        * one we're looking for it has to be exact.
+        */
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+       for (dfp = &bf[0], seenzero = matched = 0;
+            dfp < &bf[XFS_DIR2_DATA_FD_COUNT];
+            dfp++) {
+               if (!dfp->offset) {
+                       ASSERT(!dfp->length);
+                       seenzero = 1;
+                       continue;
+               }
+               ASSERT(seenzero == 0);
+               if (be16_to_cpu(dfp->offset) == off) {
+                       matched = 1;
+                       ASSERT(dfp->length == dup->length);
+               } else if (off < be16_to_cpu(dfp->offset))
+                       ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
+               else
+                       ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
+               ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
+               if (dfp > &bf[0])
+                       ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
+       }
+#endif
+       /*
+        * If this is smaller than the smallest bestfree entry,
+        * it can't be there since they're sorted.
+        */
+       if (be16_to_cpu(dup->length) <
+           be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
+               return NULL;
+       /*
+        * Look at the three bestfree entries for our guy.
+        */
+       for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
+               if (!dfp->offset)
+                       return NULL;
+               if (be16_to_cpu(dfp->offset) == off)
+                       return dfp;
+       }
+       /*
+        * Didn't find it.  This only happens if there are duplicate lengths.
+        */
+       return NULL;
+}
+
+/*
+ * Insert an unused-space entry into the bestfree table.
+ */
+xfs_dir2_data_free_t *                         /* entry inserted */
+xfs_dir2_data_freeinsert(
+       struct xfs_dir2_data_hdr *hdr,          /* data block pointer */
+       struct xfs_dir2_data_free *dfp,         /* bestfree table pointer */
+       struct xfs_dir2_data_unused *dup,       /* unused space */
+       int                     *loghead)       /* log the data header (out) */
+{
+       xfs_dir2_data_free_t    new;            /* new bestfree entry */
+
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+
+       new.length = dup->length;
+       new.offset = cpu_to_be16((char *)dup - (char *)hdr);
+
+       /*
+        * Insert at position 0, 1, or 2; or not at all.
+        */
+       if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
+               dfp[2] = dfp[1];
+               dfp[1] = dfp[0];
+               dfp[0] = new;
+               *loghead = 1;
+               return &dfp[0];
+       }
+       if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
+               dfp[2] = dfp[1];
+               dfp[1] = new;
+               *loghead = 1;
+               return &dfp[1];
+       }
+       if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
+               dfp[2] = new;
+               *loghead = 1;
+               return &dfp[2];
+       }
+       return NULL;
+}
+
+/*
+ * Remove a bestfree entry from the table.
+ */
+STATIC void
+xfs_dir2_data_freeremove(
+       struct xfs_dir2_data_hdr *hdr,          /* data block header */
+       struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
+       struct xfs_dir2_data_free *dfp,         /* bestfree entry pointer */
+       int                     *loghead)       /* out: log data header */
+{
+
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+
+       /*
+        * It's the first entry, slide the next 2 up.
+        */
+       if (dfp == &bf[0]) {
+               bf[0] = bf[1];
+               bf[1] = bf[2];
+       }
+       /*
+        * It's the second entry, slide the 3rd entry up.
+        */
+       else if (dfp == &bf[1])
+               bf[1] = bf[2];
+       /*
+        * Must be the last entry.
+        */
+       else
+               ASSERT(dfp == &bf[2]);
+       /*
+        * Clear the 3rd entry, must be zero now.
+        */
+       bf[2].length = 0;
+       bf[2].offset = 0;
+       *loghead = 1;
+}
+
+/*
+ * Given a data block, reconstruct its bestfree map.
+ */
+void
+xfs_dir2_data_freescan(
+       struct xfs_inode        *dp,
+       struct xfs_dir2_data_hdr *hdr,
+       int                     *loghead)
+{
+       xfs_dir2_block_tail_t   *btp;           /* block tail */
+       xfs_dir2_data_entry_t   *dep;           /* active data entry */
+       xfs_dir2_data_unused_t  *dup;           /* unused data entry */
+       struct xfs_dir2_data_free *bf;
+       char                    *endp;          /* end of block's data */
+       char                    *p;             /* current entry pointer */
+       struct xfs_da_geometry  *geo = dp->i_mount->m_dir_geo;
+
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+
+       /*
+        * Start by clearing the table.
+        */
+       bf = dp->d_ops->data_bestfree_p(hdr);
+       memset(bf, 0, sizeof(*bf) * XFS_DIR2_DATA_FD_COUNT);
+       *loghead = 1;
+       /*
+        * Set up pointers.
+        */
+       p = (char *)dp->d_ops->data_entry_p(hdr);
+       if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+           hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
+               btp = xfs_dir2_block_tail_p(geo, hdr);
+               endp = (char *)xfs_dir2_block_leaf_p(btp);
+       } else
+               endp = (char *)hdr + geo->blksize;
+       /*
+        * Loop over the block's entries.
+        */
+       while (p < endp) {
+               dup = (xfs_dir2_data_unused_t *)p;
+               /*
+                * If it's a free entry, insert it.
+                */
+               if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
+                       ASSERT((char *)dup - (char *)hdr ==
+                              be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
+                       xfs_dir2_data_freeinsert(hdr, bf, dup, loghead);
+                       p += be16_to_cpu(dup->length);
+               }
+               /*
+                * For active entries, check their tags and skip them.
+                */
+               else {
+                       dep = (xfs_dir2_data_entry_t *)p;
+                       ASSERT((char *)dep - (char *)hdr ==
+                              be16_to_cpu(*dp->d_ops->data_entry_tag_p(dep)));
+                       p += dp->d_ops->data_entsize(dep->namelen);
+               }
+       }
+}
+
+/*
+ * Initialize a data block at the given block number in the directory.
+ * Give back the buffer for the created block.
+ */
+int                                            /* error */
+xfs_dir3_data_init(
+       xfs_da_args_t           *args,          /* directory operation args */
+       xfs_dir2_db_t           blkno,          /* logical dir block number */
+       struct xfs_buf          **bpp)          /* output block buffer */
+{
+       struct xfs_buf          *bp;            /* block buffer */
+       xfs_dir2_data_hdr_t     *hdr;           /* data block header */
+       xfs_inode_t             *dp;            /* incore directory inode */
+       xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
+       struct xfs_dir2_data_free *bf;
+       int                     error;          /* error return value */
+       int                     i;              /* bestfree index */
+       xfs_mount_t             *mp;            /* filesystem mount point */
+       xfs_trans_t             *tp;            /* transaction pointer */
+       int                     t;              /* temp */
+
+       dp = args->dp;
+       mp = dp->i_mount;
+       tp = args->trans;
+       /*
+        * Get the buffer set up for the block.
+        */
+       error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(args->geo, blkno),
+                              -1, &bp, XFS_DATA_FORK);
+       if (error)
+               return error;
+       bp->b_ops = &xfs_dir3_data_buf_ops;
+       xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_DATA_BUF);
+
+       /*
+        * Initialize the header.
+        */
+       hdr = bp->b_addr;
+       if (xfs_sb_version_hascrc(&mp->m_sb)) {
+               struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
+
+               memset(hdr3, 0, sizeof(*hdr3));
+               hdr3->magic = cpu_to_be32(XFS_DIR3_DATA_MAGIC);
+               hdr3->blkno = cpu_to_be64(bp->b_bn);
+               hdr3->owner = cpu_to_be64(dp->i_ino);
+               uuid_copy(&hdr3->uuid, &mp->m_sb.sb_uuid);
+
+       } else
+               hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
+
+       bf = dp->d_ops->data_bestfree_p(hdr);
+       bf[0].offset = cpu_to_be16(dp->d_ops->data_entry_offset);
+       for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
+               bf[i].length = 0;
+               bf[i].offset = 0;
+       }
+
+       /*
+        * Set up an unused entry for the block's body.
+        */
+       dup = dp->d_ops->data_unused_p(hdr);
+       dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
+
+       t = args->geo->blksize - (uint)dp->d_ops->data_entry_offset;
+       bf[0].length = cpu_to_be16(t);
+       dup->length = cpu_to_be16(t);
+       *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
+       /*
+        * Log it and return it.
+        */
+       xfs_dir2_data_log_header(args, bp);
+       xfs_dir2_data_log_unused(args, bp, dup);
+       *bpp = bp;
+       return 0;
+}
+
+/*
+ * Log an active data entry from the block.
+ */
+void
+xfs_dir2_data_log_entry(
+       struct xfs_da_args      *args,
+       struct xfs_buf          *bp,
+       xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
+{
+       struct xfs_dir2_data_hdr *hdr = bp->b_addr;
+
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+
+       xfs_trans_log_buf(args->trans, bp, (uint)((char *)dep - (char *)hdr),
+               (uint)((char *)(args->dp->d_ops->data_entry_tag_p(dep) + 1) -
+                      (char *)hdr - 1));
+}
+
+/*
+ * Log a data block header.
+ */
+void
+xfs_dir2_data_log_header(
+       struct xfs_da_args      *args,
+       struct xfs_buf          *bp)
+{
+#ifdef DEBUG
+       struct xfs_dir2_data_hdr *hdr = bp->b_addr;
+
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+#endif
+
+       xfs_trans_log_buf(args->trans, bp, 0,
+                         args->dp->d_ops->data_entry_offset - 1);
+}
+
+/*
+ * Log a data unused entry.
+ */
+void
+xfs_dir2_data_log_unused(
+       struct xfs_da_args      *args,
+       struct xfs_buf          *bp,
+       xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
+{
+       xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
+
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+
+       /*
+        * Log the first part of the unused entry.
+        */
+       xfs_trans_log_buf(args->trans, bp, (uint)((char *)dup - (char *)hdr),
+               (uint)((char *)&dup->length + sizeof(dup->length) -
+                      1 - (char *)hdr));
+       /*
+        * Log the end (tag) of the unused entry.
+        */
+       xfs_trans_log_buf(args->trans, bp,
+               (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
+               (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
+                      sizeof(xfs_dir2_data_off_t) - 1));
+}
+
+/*
+ * Make a byte range in the data block unused.
+ * Its current contents are unimportant.
+ */
+void
+xfs_dir2_data_make_free(
+       struct xfs_da_args      *args,
+       struct xfs_buf          *bp,
+       xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
+       xfs_dir2_data_aoff_t    len,            /* length in bytes */
+       int                     *needlogp,      /* out: log header */
+       int                     *needscanp)     /* out: regen bestfree */
+{
+       xfs_dir2_data_hdr_t     *hdr;           /* data block pointer */
+       xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
+       char                    *endptr;        /* end of data area */
+       int                     needscan;       /* need to regen bestfree */
+       xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
+       xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
+       xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
+       struct xfs_dir2_data_free *bf;
+
+       hdr = bp->b_addr;
+
+       /*
+        * Figure out where the end of the data area is.
+        */
+       if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+           hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC))
+               endptr = (char *)hdr + args->geo->blksize;
+       else {
+               xfs_dir2_block_tail_t   *btp;   /* block tail */
+
+               ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+                       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+               btp = xfs_dir2_block_tail_p(args->geo, hdr);
+               endptr = (char *)xfs_dir2_block_leaf_p(btp);
+       }
+       /*
+        * If this isn't the start of the block, then back up to
+        * the previous entry and see if it's free.
+        */
+       if (offset > args->dp->d_ops->data_entry_offset) {
+               __be16                  *tagp;  /* tag just before us */
+
+               tagp = (__be16 *)((char *)hdr + offset) - 1;
+               prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
+               if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
+                       prevdup = NULL;
+       } else
+               prevdup = NULL;
+       /*
+        * If this isn't the end of the block, see if the entry after
+        * us is free.
+        */
+       if ((char *)hdr + offset + len < endptr) {
+               postdup =
+                       (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
+               if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
+                       postdup = NULL;
+       } else
+               postdup = NULL;
+       ASSERT(*needscanp == 0);
+       needscan = 0;
+       /*
+        * Previous and following entries are both free,
+        * merge everything into a single free entry.
+        */
+       bf = args->dp->d_ops->data_bestfree_p(hdr);
+       if (prevdup && postdup) {
+               xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
+
+               /*
+                * See if prevdup and/or postdup are in bestfree table.
+                */
+               dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
+               dfp2 = xfs_dir2_data_freefind(hdr, bf, postdup);
+               /*
+                * We need a rescan unless there are exactly 2 free entries
+                * namely our two.  Then we know what's happening, otherwise
+                * since the third bestfree is there, there might be more
+                * entries.
+                */
+               needscan = (bf[2].length != 0);
+               /*
+                * Fix up the new big freespace.
+                */
+               be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
+               *xfs_dir2_data_unused_tag_p(prevdup) =
+                       cpu_to_be16((char *)prevdup - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, prevdup);
+               if (!needscan) {
+                       /*
+                        * Has to be the case that entries 0 and 1 are
+                        * dfp and dfp2 (don't know which is which), and
+                        * entry 2 is empty.
+                        * Remove entry 1 first then entry 0.
+                        */
+                       ASSERT(dfp && dfp2);
+                       if (dfp == &bf[1]) {
+                               dfp = &bf[0];
+                               ASSERT(dfp2 == dfp);
+                               dfp2 = &bf[1];
+                       }
+                       xfs_dir2_data_freeremove(hdr, bf, dfp2, needlogp);
+                       xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
+                       /*
+                        * Now insert the new entry.
+                        */
+                       dfp = xfs_dir2_data_freeinsert(hdr, bf, prevdup,
+                                                      needlogp);
+                       ASSERT(dfp == &bf[0]);
+                       ASSERT(dfp->length == prevdup->length);
+                       ASSERT(!dfp[1].length);
+                       ASSERT(!dfp[2].length);
+               }
+       }
+       /*
+        * The entry before us is free, merge with it.
+        */
+       else if (prevdup) {
+               dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
+               be16_add_cpu(&prevdup->length, len);
+               *xfs_dir2_data_unused_tag_p(prevdup) =
+                       cpu_to_be16((char *)prevdup - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, prevdup);
+               /*
+                * If the previous entry was in the table, the new entry
+                * is longer, so it will be in the table too.  Remove
+                * the old one and add the new one.
+                */
+               if (dfp) {
+                       xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
+                       xfs_dir2_data_freeinsert(hdr, bf, prevdup, needlogp);
+               }
+               /*
+                * Otherwise we need a scan if the new entry is big enough.
+                */
+               else {
+                       needscan = be16_to_cpu(prevdup->length) >
+                                  be16_to_cpu(bf[2].length);
+               }
+       }
+       /*
+        * The following entry is free, merge with it.
+        */
+       else if (postdup) {
+               dfp = xfs_dir2_data_freefind(hdr, bf, postdup);
+               newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
+               newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
+               newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
+               *xfs_dir2_data_unused_tag_p(newdup) =
+                       cpu_to_be16((char *)newdup - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, newdup);
+               /*
+                * If the following entry was in the table, the new entry
+                * is longer, so it will be in the table too.  Remove
+                * the old one and add the new one.
+                */
+               if (dfp) {
+                       xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
+                       xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
+               }
+               /*
+                * Otherwise we need a scan if the new entry is big enough.
+                */
+               else {
+                       needscan = be16_to_cpu(newdup->length) >
+                                  be16_to_cpu(bf[2].length);
+               }
+       }
+       /*
+        * Neither neighbor is free.  Make a new entry.
+        */
+       else {
+               newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
+               newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
+               newdup->length = cpu_to_be16(len);
+               *xfs_dir2_data_unused_tag_p(newdup) =
+                       cpu_to_be16((char *)newdup - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, newdup);
+               xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
+       }
+       *needscanp = needscan;
+}
+
+/*
+ * Take a byte range out of an existing unused space and make it un-free.
+ */
+void
+xfs_dir2_data_use_free(
+       struct xfs_da_args      *args,
+       struct xfs_buf          *bp,
+       xfs_dir2_data_unused_t  *dup,           /* unused entry */
+       xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
+       xfs_dir2_data_aoff_t    len,            /* length to use */
+       int                     *needlogp,      /* out: need to log header */
+       int                     *needscanp)     /* out: need regen bestfree */
+{
+       xfs_dir2_data_hdr_t     *hdr;           /* data block header */
+       xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
+       int                     matchback;      /* matches end of freespace */
+       int                     matchfront;     /* matches start of freespace */
+       int                     needscan;       /* need to regen bestfree */
+       xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
+       xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
+       int                     oldlen;         /* old unused entry's length */
+       struct xfs_dir2_data_free *bf;
+
+       hdr = bp->b_addr;
+       ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
+              hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
+       ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
+       ASSERT(offset >= (char *)dup - (char *)hdr);
+       ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
+       ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
+       /*
+        * Look up the entry in the bestfree table.
+        */
+       oldlen = be16_to_cpu(dup->length);
+       bf = args->dp->d_ops->data_bestfree_p(hdr);
+       dfp = xfs_dir2_data_freefind(hdr, bf, dup);
+       ASSERT(dfp || oldlen <= be16_to_cpu(bf[2].length));
+       /*
+        * Check for alignment with front and back of the entry.
+        */
+       matchfront = (char *)dup - (char *)hdr == offset;
+       matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
+       ASSERT(*needscanp == 0);
+       needscan = 0;
+       /*
+        * If we matched it exactly we just need to get rid of it from
+        * the bestfree table.
+        */
+       if (matchfront && matchback) {
+               if (dfp) {
+                       needscan = (bf[2].offset != 0);
+                       if (!needscan)
+                               xfs_dir2_data_freeremove(hdr, bf, dfp,
+                                                        needlogp);
+               }
+       }
+       /*
+        * We match the first part of the entry.
+        * Make a new entry with the remaining freespace.
+        */
+       else if (matchfront) {
+               newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
+               newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
+               newdup->length = cpu_to_be16(oldlen - len);
+               *xfs_dir2_data_unused_tag_p(newdup) =
+                       cpu_to_be16((char *)newdup - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, newdup);
+               /*
+                * If it was in the table, remove it and add the new one.
+                */
+               if (dfp) {
+                       xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
+                       dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
+                                                      needlogp);
+                       ASSERT(dfp != NULL);
+                       ASSERT(dfp->length == newdup->length);
+                       ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
+                       /*
+                        * If we got inserted at the last slot,
+                        * that means we don't know if there was a better
+                        * choice for the last slot, or not.  Rescan.
+                        */
+                       needscan = dfp == &bf[2];
+               }
+       }
+       /*
+        * We match the last part of the entry.
+        * Trim the allocated space off the tail of the entry.
+        */
+       else if (matchback) {
+               newdup = dup;
+               newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
+               *xfs_dir2_data_unused_tag_p(newdup) =
+                       cpu_to_be16((char *)newdup - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, newdup);
+               /*
+                * If it was in the table, remove it and add the new one.
+                */
+               if (dfp) {
+                       xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
+                       dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
+                                                      needlogp);
+                       ASSERT(dfp != NULL);
+                       ASSERT(dfp->length == newdup->length);
+                       ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
+                       /*
+                        * If we got inserted at the last slot,
+                        * that means we don't know if there was a better
+                        * choice for the last slot, or not.  Rescan.
+                        */
+                       needscan = dfp == &bf[2];
+               }
+       }
+       /*
+        * Poking out the middle of an entry.
+        * Make two new entries.
+        */
+       else {
+               newdup = dup;
+               newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
+               *xfs_dir2_data_unused_tag_p(newdup) =
+                       cpu_to_be16((char *)newdup - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, newdup);
+               newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
+               newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
+               newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
+               *xfs_dir2_data_unused_tag_p(newdup2) =
+                       cpu_to_be16((char *)newdup2 - (char *)hdr);
+               xfs_dir2_data_log_unused(args, bp, newdup2);
+               /*
+                * If the old entry was in the table, we need to scan
+                * if the 3rd entry was valid, since these entries
+                * are smaller than the old one.
+                * If we don't need to scan that means there were 1 or 2
+                * entries in the table, and removing the old and adding
+                * the 2 new will work.
+                */
+               if (dfp) {
+                       needscan = (bf[2].length != 0);
+                       if (!needscan) {
+                               xfs_dir2_data_freeremove(hdr, bf, dfp,
+                                                        needlogp);
+                               xfs_dir2_data_freeinsert(hdr, bf, newdup,
+                                                        needlogp);
+                               xfs_dir2_data_freeinsert(hdr, bf, newdup2,
+                                                        needlogp);
+                       }
+               }
+       }
+       *needscanp = needscan;
+}