1 files changed, 1845 insertions, 63 deletions

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 76ffb5c..0b8c88b 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -41,6 +41,7 @@
 #include <linux/slab.h>
 #include <linux/highmem.h>
 #include <linux/quotaops.h>
+#include <linux/sort.h>
 
 #define MLOG_MASK_PREFIX ML_NAMEI
 #include <cluster/masklog.h>
@@ -58,6 +59,7 @@
 #include "namei.h"
 #include "suballoc.h"
 #include "super.h"
+#include "sysfile.h"
 #include "uptodate.h"
 
 #include "buffer_head_io.h"
@@ -71,11 +73,6 @@ static unsigned char ocfs2_filetype_table[] = {
 	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
 };
 
-static int ocfs2_extend_dir(struct ocfs2_super *osb,
-			    struct inode *dir,
-			    struct buffer_head *parent_fe_bh,
-			    unsigned int blocks_wanted,
-			    struct buffer_head **new_de_bh);
 static int ocfs2_do_extend_dir(struct super_block *sb,
 			       handle_t *handle,
 			       struct inode *dir,
@@ -155,6 +152,105 @@ static void ocfs2_init_dir_trailer(struct inode *inode,
 void ocfs2_free_dir_lookup_result(struct ocfs2_dir_lookup_result *res)
 {
 	brelse(res->dl_leaf_bh);
+	brelse(res->dl_dx_leaf_bh);
+}
+
+static int ocfs2_dir_indexed(struct inode *inode)
+{
+	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INDEXED_DIR_FL)
+		return 1;
+	return 0;
+}
+
+/*
+ * Hashing code adapted from ext3
+ */
+#define DELTA 0x9E3779B9
+
+static void TEA_transform(__u32 buf[4], __u32 const in[])
+{
+	__u32	sum = 0;
+	__u32	b0 = buf[0], b1 = buf[1];
+	__u32	a = in[0], b = in[1], c = in[2], d = in[3];
+	int	n = 16;
+
+	do {
+		sum += DELTA;
+		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
+		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
+	} while (--n);
+
+	buf[0] += b0;
+	buf[1] += b1;
+}
+
+static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
+{
+	__u32	pad, val;
+	int	i;
+
+	pad = (__u32)len | ((__u32)len << 8);
+	pad |= pad << 16;
+
+	val = pad;
+	if (len > num*4)
+		len = num * 4;
+	for (i = 0; i < len; i++) {
+		if ((i % 4) == 0)
+			val = pad;
+		val = msg[i] + (val << 8);
+		if ((i % 4) == 3) {
+			*buf++ = val;
+			val = pad;
+			num--;
+		}
+	}
+	if (--num >= 0)
+		*buf++ = val;
+	while (--num >= 0)
+		*buf++ = pad;
+}
+
+static void ocfs2_dx_dir_name_hash(struct inode *dir, const char *name, int len,
+				   struct ocfs2_dx_hinfo *hinfo)
+{
+	struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
+	const char	*p;
+	__u32		in[8], buf[4];
+
+	/*
+	 * XXX: Is this really necessary, if the index is never looked
+	 * at by readdir? Is a hash value of '0' a bad idea?
+	 */
+	if ((len == 1 && !strncmp(".", name, 1)) ||
+	    (len == 2 && !strncmp("..", name, 2))) {
+		buf[0] = buf[1] = 0;
+		goto out;
+	}
+
+#ifdef OCFS2_DEBUG_DX_DIRS
+	/*
+	 * This makes it very easy to debug indexing problems. We
+	 * should never allow this to be selected without hand editing
+	 * this file though.
+	 */
+	buf[0] = buf[1] = len;
+	goto out;
+#endif
+
+	memcpy(buf, osb->osb_dx_seed, sizeof(buf));
+
+	p = name;
+	while (len > 0) {
+		str2hashbuf(p, len, in, 4);
+		TEA_transform(buf, in);
+		len -= 16;
+		p += 16;
+	}
+
+out:
+	hinfo->major_hash = buf[0];
+	hinfo->minor_hash = buf[1];
 }
 
 /*
@@ -317,6 +413,52 @@ static int ocfs2_validate_dir_block(struct super_block *sb,
 }
 
 /*
+ * Validate a directory trailer.
+ *
+ * We check the trailer here rather than in ocfs2_validate_dir_block()
+ * because that function doesn't have the inode to test.
+ */
+static int ocfs2_check_dir_trailer(struct inode *dir, struct buffer_head *bh)
+{
+	int rc = 0;
+	struct ocfs2_dir_block_trailer *trailer;
+
+	trailer = ocfs2_trailer_from_bh(bh, dir->i_sb);
+	if (!OCFS2_IS_VALID_DIR_TRAILER(trailer)) {
+		rc = -EINVAL;
+		ocfs2_error(dir->i_sb,
+			    "Invalid dirblock #%llu: "
+			    "signature = %.*s\n",
+			    (unsigned long long)bh->b_blocknr, 7,
+			    trailer->db_signature);
+		goto out;
+	}
+	if (le64_to_cpu(trailer->db_blkno) != bh->b_blocknr) {
+		rc = -EINVAL;
+		ocfs2_error(dir->i_sb,
+			    "Directory block #%llu has an invalid "
+			    "db_blkno of %llu",
+			    (unsigned long long)bh->b_blocknr,
+			    (unsigned long long)le64_to_cpu(trailer->db_blkno));
+		goto out;
+	}
+	if (le64_to_cpu(trailer->db_parent_dinode) !=
+	    OCFS2_I(dir)->ip_blkno) {
+		rc = -EINVAL;
+		ocfs2_error(dir->i_sb,
+			    "Directory block #%llu on dinode "
+			    "#%llu has an invalid parent_dinode "
+			    "of %llu",
+			    (unsigned long long)bh->b_blocknr,
+			    (unsigned long long)OCFS2_I(dir)->ip_blkno,
+			    (unsigned long long)le64_to_cpu(trailer->db_blkno));
+		goto out;
+	}
+out:
+	return rc;
+}
+
+/*
  * This function forces all errors to -EIO for consistency with its
  * predecessor, ocfs2_bread().  We haven't audited what returning the
  * real error codes would do to callers.  We log the real codes with
@@ -327,7 +469,6 @@ static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
 {
 	int rc = 0;
 	struct buffer_head *tmp = *bh;
-	struct ocfs2_dir_block_trailer *trailer;
 
 	rc = ocfs2_read_virt_blocks(inode, v_block, 1, &tmp, flags,
 				    ocfs2_validate_dir_block);
@@ -336,42 +477,13 @@ static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
 		goto out;
 	}
 
-	/*
-	 * We check the trailer here rather than in
-	 * ocfs2_validate_dir_block() because that function doesn't have
-	 * the inode to test.
-	 */
 	if (!(flags & OCFS2_BH_READAHEAD) &&
 	    ocfs2_dir_has_trailer(inode)) {
-		trailer = ocfs2_trailer_from_bh(tmp, inode->i_sb);
-		if (!OCFS2_IS_VALID_DIR_TRAILER(trailer)) {
-			rc = -EINVAL;
-			ocfs2_error(inode->i_sb,
-				    "Invalid dirblock #%llu: "
-				    "signature = %.*s\n",
-				    (unsigned long long)tmp->b_blocknr, 7,
-				    trailer->db_signature);
-			goto out;
-		}
-		if (le64_to_cpu(trailer->db_blkno) != tmp->b_blocknr) {
-			rc = -EINVAL;
-			ocfs2_error(inode->i_sb,
-				    "Directory block #%llu has an invalid "
-				    "db_blkno of %llu",
-				    (unsigned long long)tmp->b_blocknr,
-				    (unsigned long long)le64_to_cpu(trailer->db_blkno));
-			goto out;
-		}
-		if (le64_to_cpu(trailer->db_parent_dinode) !=
-		    OCFS2_I(inode)->ip_blkno) {
-			rc = -EINVAL;
-			ocfs2_error(inode->i_sb,
-				    "Directory block #%llu on dinode "
-				    "#%llu has an invalid parent_dinode "
-				    "of %llu",
-				    (unsigned long long)tmp->b_blocknr,
-				    (unsigned long long)OCFS2_I(inode)->ip_blkno,
-				    (unsigned long long)le64_to_cpu(trailer->db_blkno));
+		rc = ocfs2_check_dir_trailer(inode, tmp);
+		if (rc) {
+			if (!*bh)
+				brelse(tmp);
+			mlog_errno(rc);
 			goto out;
 		}
 	}
@@ -384,6 +496,141 @@ out:
 	return rc ? -EIO : 0;
 }
 
+/*
+ * Read the block at 'phys' which belongs to this directory
+ * inode. This function does no virtual->physical block translation -
+ * what's passed in is assumed to be a valid directory block.
+ */
+static int ocfs2_read_dir_block_direct(struct inode *dir, u64 phys,
+				       struct buffer_head **bh)
+{
+	int ret;
+	struct buffer_head *tmp = *bh;
+
+	ret = ocfs2_read_block(dir, phys, &tmp, ocfs2_validate_dir_block);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (ocfs2_supports_dir_trailer(dir)) {
+		ret = ocfs2_check_dir_trailer(dir, tmp);
+		if (ret) {
+			if (!*bh)
+				brelse(tmp);
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	if (!ret && !*bh)
+		*bh = tmp;
+out:
+	return ret;
+}
+
+static int ocfs2_validate_dx_root(struct super_block *sb,
+				  struct buffer_head *bh)
+{
+	int ret;
+	struct ocfs2_dx_root_block *dx_root;
+
+	BUG_ON(!buffer_uptodate(bh));
+
+	dx_root = (struct ocfs2_dx_root_block *) bh->b_data;
+
+	ret = ocfs2_validate_meta_ecc(sb, bh->b_data, &dx_root->dr_check);
+	if (ret) {
+		mlog(ML_ERROR,
+		     "Checksum failed for dir index root block %llu\n",
+		     (unsigned long long)bh->b_blocknr);
+		return ret;
+	}
+
+	if (!OCFS2_IS_VALID_DX_ROOT(dx_root)) {
+		ocfs2_error(sb,
+			    "Dir Index Root # %llu has bad signature %.*s",
+			    (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
+			    7, dx_root->dr_signature);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ocfs2_read_dx_root(struct inode *dir, struct ocfs2_dinode *di,
+			      struct buffer_head **dx_root_bh)
+{
+	int ret;
+	u64 blkno = le64_to_cpu(di->i_dx_root);
+	struct buffer_head *tmp = *dx_root_bh;
+
+	ret = ocfs2_read_block(dir, blkno, &tmp, ocfs2_validate_dx_root);
+
+	/* If ocfs2_read_block() got us a new bh, pass it up. */
+	if (!ret && !*dx_root_bh)
+		*dx_root_bh = tmp;
+
+	return ret;
+}
+
+static int ocfs2_validate_dx_leaf(struct super_block *sb,
+				  struct buffer_head *bh)
+{
+	int ret;
+	struct ocfs2_dx_leaf *dx_leaf = (struct ocfs2_dx_leaf *)bh->b_data;
+
+	BUG_ON(!buffer_uptodate(bh));
+
+	ret = ocfs2_validate_meta_ecc(sb, bh->b_data, &dx_leaf->dl_check);
+	if (ret) {
+		mlog(ML_ERROR,
+		     "Checksum failed for dir index leaf block %llu\n",
+		     (unsigned long long)bh->b_blocknr);
+		return ret;
+	}
+
+	if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf)) {
+		ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s",
+			    7, dx_leaf->dl_signature);
+		return -EROFS;
+	}
+
+	return 0;
+}
+
+static int ocfs2_read_dx_leaf(struct inode *dir, u64 blkno,
+			      struct buffer_head **dx_leaf_bh)
+{
+	int ret;
+	struct buffer_head *tmp = *dx_leaf_bh;
+
+	ret = ocfs2_read_block(dir, blkno, &tmp, ocfs2_validate_dx_leaf);
+
+	/* If ocfs2_read_block() got us a new bh, pass it up. */
+	if (!ret && !*dx_leaf_bh)
+		*dx_leaf_bh = tmp;
+
+	return ret;
+}
+
+/*
+ * Read a series of dx_leaf blocks. This expects all buffer_head
+ * pointers to be NULL on function entry.
+ */
+static int ocfs2_read_dx_leaves(struct inode *dir, u64 start, int num,
+				struct buffer_head **dx_leaf_bhs)
+{
+	int ret;
+
+	ret = ocfs2_read_blocks(dir, start, num, dx_leaf_bhs, 0,
+				ocfs2_validate_dx_leaf);
+	if (ret)
+		mlog_errno(ret);
+
+	return ret;
+}
+
 static struct buffer_head *ocfs2_find_entry_el(const char *name, int namelen,
 					       struct inode *dir,
 					       struct ocfs2_dir_entry **res_dir)
@@ -485,6 +732,270 @@ cleanup_and_exit:
 	return ret;
 }
 
+static int ocfs2_dx_dir_lookup_rec(struct inode *inode,
+				   struct ocfs2_extent_list *el,
+				   u32 major_hash,
+				   u32 *ret_cpos,
+				   u64 *ret_phys_blkno,
+				   unsigned int *ret_clen)
+{
+	int ret = 0, i, found;
+	struct buffer_head *eb_bh = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_rec *rec = NULL;
+
+	if (el->l_tree_depth) {
+		ret = ocfs2_find_leaf(inode, el, major_hash, &eb_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+		el = &eb->h_list;
+
+		if (el->l_tree_depth) {
+			ocfs2_error(inode->i_sb,
+				    "Inode %lu has non zero tree depth in "
+				    "btree tree block %llu\n", inode->i_ino,
+				    (unsigned long long)eb_bh->b_blocknr);
+			ret = -EROFS;
+			goto out;
+		}
+	}
+
+	found = 0;
+	for (i = le16_to_cpu(el->l_next_free_rec) - 1; i >= 0; i--) {
+		rec = &el->l_recs[i];
+
+		if (le32_to_cpu(rec->e_cpos) <= major_hash) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found) {
+		ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
+			    "record (%u, %u, 0) in btree", inode->i_ino,
+			    le32_to_cpu(rec->e_cpos),
+			    ocfs2_rec_clusters(el, rec));
+		ret = -EROFS;
+		goto out;
+	}
+
+	if (ret_phys_blkno)
+		*ret_phys_blkno = le64_to_cpu(rec->e_blkno);
+	if (ret_cpos)
+		*ret_cpos = le32_to_cpu(rec->e_cpos);
+	if (ret_clen)
+		*ret_clen = le16_to_cpu(rec->e_leaf_clusters);
+
+out:
+	brelse(eb_bh);
+	return ret;
+}
+
+/*
+ * Returns the block index, from the start of the cluster which this
+ * hash belongs too.
+ */
+static unsigned int ocfs2_dx_dir_hash_idx(struct ocfs2_super *osb,
+					  struct ocfs2_dx_hinfo *hinfo)
+{
+	u32 minor_hash = hinfo->minor_hash;
+	return minor_hash & osb->osb_dx_mask;
+}
+
+static int ocfs2_dx_dir_lookup(struct inode *inode,
+			       struct ocfs2_extent_list *el,
+			       struct ocfs2_dx_hinfo *hinfo,
+			       u32 *ret_cpos,
+			       u64 *ret_phys_blkno)
+{
+	int ret = 0;
+	unsigned int cend, uninitialized_var(clen);
+	u32 uninitialized_var(cpos);
+	u64 uninitialized_var(blkno);
+	u32 name_hash = hinfo->major_hash;
+
+	ret = ocfs2_dx_dir_lookup_rec(inode, el, name_hash, &cpos, &blkno,
+				      &clen);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	cend = cpos + clen;
+	if (name_hash >= cend) {
+		/* We want the last cluster */
+		blkno += ocfs2_clusters_to_blocks(inode->i_sb, clen - 1);
+		cpos += clen - 1;
+	} else {
+		blkno += ocfs2_clusters_to_blocks(inode->i_sb,
+						  name_hash - cpos);
+		cpos = name_hash;
+	}
+
+	/*
+	 * We now have the cluster which should hold our entry. To
+	 * find the exact block from the start of the cluster to
+	 * search, we take the lower bits of the hash.
+	 */
+	blkno += ocfs2_dx_dir_hash_idx(OCFS2_SB(inode->i_sb), hinfo);
+
+	if (ret_phys_blkno)
+		*ret_phys_blkno = blkno;
+	if (ret_cpos)
+		*ret_cpos = cpos;
+
+out:
+
+	return ret;
+}
+
+static int ocfs2_dx_dir_search(const char *name, int namelen,
+			       struct inode *dir,
+			       struct ocfs2_extent_list *dr_el,
+			       struct ocfs2_dir_lookup_result *res)
+{
+	int ret, i, found;
+	u64 uninitialized_var(phys);
+	struct buffer_head *dx_leaf_bh = NULL;
+	struct ocfs2_dx_leaf *dx_leaf;
+	struct ocfs2_dx_entry *dx_entry = NULL;
+	struct buffer_head *dir_ent_bh = NULL;
+	struct ocfs2_dir_entry *dir_ent = NULL;
+	struct ocfs2_dx_hinfo *hinfo = &res->dl_hinfo;
+
+	ocfs2_dx_dir_name_hash(dir, name, namelen, &res->dl_hinfo);
+
+	ret = ocfs2_dx_dir_lookup(dir, dr_el, hinfo, NULL, &phys);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	mlog(0, "Dir %llu: name: \"%.*s\", lookup of hash: %u.0x%x "
+	     "returns: %llu\n",
+	     (unsigned long long)OCFS2_I(dir)->ip_blkno,
+	     namelen, name, hinfo->major_hash, hinfo->minor_hash,
+	     (unsigned long long)phys);
+
+	ret = ocfs2_read_dx_leaf(dir, phys, &dx_leaf_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	dx_leaf = (struct ocfs2_dx_leaf *) dx_leaf_bh->b_data;
+
+	mlog(0, "leaf info: num_used: %d, count: %d\n",
+	     le16_to_cpu(dx_leaf->dl_list.de_num_used),
+	     le16_to_cpu(dx_leaf->dl_list.de_count));
+
+	/*
+	 * Empty leaf is legal, so no need to check for that.
+	 */
+	found = 0;
+	for (i = 0; i < le16_to_cpu(dx_leaf->dl_list.de_num_used); i++) {
+		dx_entry = &dx_leaf->dl_list.de_entries[i];
+
+		if (hinfo->major_hash != le32_to_cpu(dx_entry->dx_major_hash)
+		    || hinfo->minor_hash != le32_to_cpu(dx_entry->dx_minor_hash))
+			continue;
+
+		/*
+		 * Search unindexed leaf block now. We're not
+		 * guaranteed to find anything.
+		 */
+		ret = ocfs2_read_dir_block_direct(dir,
+					  le64_to_cpu(dx_entry->dx_dirent_blk),
+					  &dir_ent_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * XXX: We should check the unindexed block here,
+		 * before using it.
+		 */
+
+		found = ocfs2_search_dirblock(dir_ent_bh, dir, name, namelen,
+					      0, dir_ent_bh->b_data,
+					      dir->i_sb->s_blocksize, &dir_ent);
+		if (found == 1)
+			break;
+
+		if (found == -1) {
+			/* This means we found a bad directory entry. */
+			ret = -EIO;
+			mlog_errno(ret);
+			goto out;
+		}
+
+		brelse(dir_ent_bh);
+		dir_ent_bh = NULL;
+	}
+
+	if (found <= 0) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	res->dl_leaf_bh = dir_ent_bh;
+	res->dl_entry = dir_ent;
+	res->dl_dx_leaf_bh = dx_leaf_bh;
+	res->dl_dx_entry = dx_entry;
+
+	ret = 0;
+out:
+	if (ret) {
+		brelse(dx_leaf_bh);
+		brelse(dir_ent_bh);
+	}
+	return ret;
+}
+
+static int ocfs2_find_entry_dx(const char *name, int namelen,
+			       struct inode *dir,
+			       struct ocfs2_dir_lookup_result *lookup)
+{
+	int ret;
+	struct buffer_head *di_bh = NULL;
+	struct ocfs2_dinode *di;
+	struct buffer_head *dx_root_bh = NULL;
+	struct ocfs2_dx_root_block *dx_root;
+
+	ret = ocfs2_read_inode_block(dir, &di_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	di = (struct ocfs2_dinode *)di_bh->b_data;
+
+	ret = ocfs2_read_dx_root(dir, di, &dx_root_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+	dx_root = (struct ocfs2_dx_root_block *) dx_root_bh->b_data;
+
+	ret = ocfs2_dx_dir_search(name, namelen, dir, &dx_root->dr_list,
+				  lookup);
+	if (ret) {
+		if (ret != -ENOENT)
+			mlog_errno(ret);
+		goto out;
+	}
+
+out:
+	brelse(di_bh);
+	brelse(dx_root_bh);
+	return ret;
+}
+
 /*
  * Try to find an entry of the provided name within 'dir'.
  *
@@ -493,10 +1004,11 @@ cleanup_and_exit:
  * other directory manipulation functions.
  *
  * Caller can NOT assume anything about the contents of the
- * buffer_heads - they are passed back only so that it can be passed into
- * any one of the manipulation functions (add entry, delete entry,
- * etc). As an example, bh in the extent directory case is a data
- * block, in the inline-data case it actually points to an inode.
+ * buffer_heads - they are passed back only so that it can be passed
+ * into any one of the manipulation functions (add entry, delete
+ * entry, etc). As an example, bh in the extent directory case is a
+ * data block, in the inline-data case it actually points to an inode,
+ * in the indexed directory case, multiple buffers are involved.
  */
 int ocfs2_find_entry(const char *name, int namelen,
 		     struct inode *dir, struct ocfs2_dir_lookup_result *lookup)
@@ -504,6 +1016,14 @@ int ocfs2_find_entry(const char *name, int namelen,
 	struct buffer_head *bh;
 	struct ocfs2_dir_entry *res_dir = NULL;
 
+	if (ocfs2_dir_indexed(dir))
+		return ocfs2_find_entry_dx(name, namelen, dir, lookup);
+
+	/*
+	 * The unindexed dir code only uses part of the lookup
+	 * structure, so there's no reason to push it down further
+	 * than this.
+	 */
 	if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
 		bh = ocfs2_find_entry_id(name, namelen, dir, &res_dir);
 	else
@@ -553,6 +1073,10 @@ out:
 	return ret;
 }
 
+/*
+ * __ocfs2_delete_entry deletes a directory entry by merging it with the
+ * previous entry
+ */
 static int __ocfs2_delete_entry(handle_t *handle, struct inode *dir,
 				struct ocfs2_dir_entry *de_del,
 				struct buffer_head *bh, char *first_de,
@@ -602,6 +1126,79 @@ bail:
 	return status;
 }
 
+static void ocfs2_dx_leaf_remove_entry(struct ocfs2_dx_leaf *dx_leaf, int index)
+{
+	struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
+	int num_used = le16_to_cpu(dl_list->de_num_used);
+
+	if (num_used == 1 || index == (num_used - 1))
+		goto clear;
+
+	memmove(&dl_list->de_entries[index], &dl_list->de_entries[index + 1],
+		(num_used - index - 1)*sizeof(struct ocfs2_dx_entry));
+clear:
+	num_used--;
+	memset(&dl_list->de_entries[num_used], 0,
+	       sizeof(struct ocfs2_dx_entry));
+	dl_list->de_num_used = cpu_to_le16(num_used);
+}
+
+static int ocfs2_delete_entry_dx(handle_t *handle, struct inode *dir,
+				 struct ocfs2_dir_lookup_result *lookup)
+{
+	int ret, index;
+	struct buffer_head *leaf_bh = lookup->dl_leaf_bh;
+	struct ocfs2_dx_leaf *dx_leaf;
+	struct ocfs2_dx_entry *dx_entry = lookup->dl_dx_entry;
+
+	dx_leaf = (struct ocfs2_dx_leaf *) lookup->dl_dx_leaf_bh->b_data;
+	/* Neither of these are a disk corruption - that should have
+	 * been caught by lookup, before we got here. */
+	BUG_ON(le16_to_cpu(dx_leaf->dl_list.de_count) <= 0);
+	BUG_ON(le16_to_cpu(dx_leaf->dl_list.de_num_used) <= 0);
+
+	index = (char *)dx_entry - (char *)dx_leaf->dl_list.de_entries;
+	index /= sizeof(*dx_entry);
+
+	if (index >= le16_to_cpu(dx_leaf->dl_list.de_num_used)) {
+		mlog(ML_ERROR, "Dir %llu: Bad dx_entry ptr idx %d, (%p, %p)\n",
+		     (unsigned long long)OCFS2_I(dir)->ip_blkno, index, dx_leaf,
+		     dx_entry);
+		return -EIO;
+	}
+
+	mlog(0, "Dir %llu: delete entry at index: %d\n",
+	     (unsigned long long)OCFS2_I(dir)->ip_blkno, index);
+
+	/*
+	 * Add the index leaf into the journal before removing the
+	 * unindexed entry. If we get an error return from
+	 * __ocfs2_delete_entry(), then it hasn't removed the entry
+	 * yet. Likewise, successful return means we *must* remove the
+	 * indexed entry.
+	 */
+	ret = ocfs2_journal_access_dl(handle, dir, lookup->dl_dx_leaf_bh,
+				      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = __ocfs2_delete_entry(handle, dir, lookup->dl_entry,
+				   leaf_bh, leaf_bh->b_data, leaf_bh->b_size);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_dx_leaf_remove_entry(dx_leaf, index);
+
+	ocfs2_journal_dirty(handle, lookup->dl_dx_leaf_bh);
+
+out:
+	return ret;
+}
+
 static inline int ocfs2_delete_entry_id(handle_t *handle,
 					struct inode *dir,
 					struct ocfs2_dir_entry *de_del,
@@ -639,13 +1236,16 @@ static inline int ocfs2_delete_entry_el(handle_t *handle,
 }
 
 /*
- * ocfs2_delete_entry deletes a directory entry by merging it with the
- * previous entry
+ * Delete a directory entry. Hide the details of directory
+ * implementation from the caller.
  */
 int ocfs2_delete_entry(handle_t *handle,
 		       struct inode *dir,
 		       struct ocfs2_dir_lookup_result *res)
 {
+	if (ocfs2_dir_indexed(dir))
+		return ocfs2_delete_entry_dx(handle, dir, res);
+
 	if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
 		return ocfs2_delete_entry_id(handle, dir, res->dl_entry,
 					     res->dl_leaf_bh);
@@ -679,6 +1279,58 @@ static inline int ocfs2_dirent_would_fit(struct ocfs2_dir_entry *de,
 	return 0;
 }
 
+static void ocfs2_dx_dir_leaf_insert_tail(struct ocfs2_dx_leaf *dx_leaf,
+					  struct ocfs2_dx_entry *dx_new_entry)
+{
+	int i;
+
+	i = le16_to_cpu(dx_leaf->dl_list.de_num_used);
+	dx_leaf->dl_list.de_entries[i] = *dx_new_entry;
+
+	le16_add_cpu(&dx_leaf->dl_list.de_num_used, 1);
+}
+
+static int __ocfs2_dx_dir_leaf_insert(struct inode *dir, handle_t *handle,
+				      struct ocfs2_dx_hinfo *hinfo,
+				      u64 dirent_blk,
+				      struct buffer_head *dx_leaf_bh)
+{
+	int ret, i;
+	struct ocfs2_dx_entry *dx_entry;
+	struct ocfs2_dx_leaf *dx_leaf;
+
+	ret = ocfs2_journal_access_dl(handle, dir, dx_leaf_bh,
+				      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	dx_leaf = (struct ocfs2_dx_leaf *)dx_leaf_bh->b_data;
+	i = le16_to_cpu(dx_leaf->dl_list.de_num_used);
+	dx_entry = &dx_leaf->dl_list.de_entries[i];
+
+	memset(dx_entry, 0, sizeof(*dx_entry));
+	dx_entry->dx_major_hash = cpu_to_le32(hinfo->major_hash);
+	dx_entry->dx_minor_hash = cpu_to_le32(hinfo->minor_hash);
+	dx_entry->dx_dirent_blk = cpu_to_le64(dirent_blk);
+
+	le16_add_cpu(&dx_leaf->dl_list.de_num_used, 1);
+
+	ocfs2_journal_dirty(handle, dx_leaf_bh);
+
+out:
+	return ret;
+}
+
+static int ocfs2_dx_dir_leaf_insert(struct inode *dir, handle_t *handle,
+				    struct ocfs2_dir_lookup_result *lookup)
+{
+	return __ocfs2_dx_dir_leaf_insert(dir, handle, &lookup->dl_hinfo,
+					  lookup->dl_leaf_bh->b_blocknr,
+					  lookup->dl_dx_leaf_bh);
+}
+
 /* we don't always have a dentry for what we want to add, so people
  * like orphan dir can call this instead.
  *
@@ -754,10 +1406,21 @@ int __ocfs2_add_entry(handle_t *handle,
 				status = ocfs2_journal_access_di(handle, dir,
 								 insert_bh,
 								 OCFS2_JOURNAL_ACCESS_WRITE);
-			else
+			else {
 				status = ocfs2_journal_access_db(handle, dir,
 								 insert_bh,
 								 OCFS2_JOURNAL_ACCESS_WRITE);
+				if (ocfs2_dir_indexed(dir)) {
+					status = ocfs2_dx_dir_leaf_insert(dir,
+									handle,
+									lookup);
+					if (status) {
+						mlog_errno(status);
+						goto bail;
+					}
+				}
+			}
+
 			/* By now the buffer is marked for journaling */
 			offset += le16_to_cpu(de->rec_len);
 			if (le64_to_cpu(de->inode)) {
@@ -887,6 +1550,10 @@ out:
 	return 0;
 }
 
+/*
+ * NOTE: This function can be called against unindexed directories,
+ * and indexed ones.
+ */
 static int ocfs2_dir_foreach_blk_el(struct inode *inode,
 				    u64 *f_version,
 				    loff_t *f_pos, void *priv,
@@ -1184,6 +1851,8 @@ static int ocfs2_empty_dir_filldir(void *priv, const char *name, int name_len,
  * routine to check that the specified directory is empty (for rmdir)
  *
  * Returns 1 if dir is empty, zero otherwise.
+ *
+ * XXX: This is a performance problem
  */
 int ocfs2_empty_dir(struct inode *inode)
 {
@@ -1285,7 +1954,8 @@ static int ocfs2_fill_new_dir_el(struct ocfs2_super *osb,
 				 struct inode *parent,
 				 struct inode *inode,
 				 struct buffer_head *fe_bh,
-				 struct ocfs2_alloc_context *data_ac)
+				 struct ocfs2_alloc_context *data_ac,
+				 struct buffer_head **ret_new_bh)
 {
 	int status;
 	unsigned int size = osb->sb->s_blocksize;
@@ -1334,6 +2004,10 @@ static int ocfs2_fill_new_dir_el(struct ocfs2_super *osb,
 	}
 
 	status = 0;
+	if (ret_new_bh) {
+		*ret_new_bh = new_bh;
+		new_bh = NULL;
+	}
 bail:
 	brelse(new_bh);
 
@@ -1341,20 +2015,382 @@ bail:
 	return status;
 }
 
+static int ocfs2_dx_dir_attach_index(struct ocfs2_super *osb,
+				     handle_t *handle, struct inode *dir,
+				     struct buffer_head *di_bh,
+				     struct ocfs2_alloc_context *meta_ac,
+				     struct buffer_head **ret_dx_root_bh)
+{
+	int ret;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;
+	u16 dr_suballoc_bit;
+	u64 dr_blkno;
+	unsigned int num_bits;
+	struct buffer_head *dx_root_bh = NULL;
+	struct ocfs2_dx_root_block *dx_root;
+
+	ret = ocfs2_claim_metadata(osb, handle, meta_ac, 1, &dr_suballoc_bit,
+				   &num_bits, &dr_blkno);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	mlog(0, "Dir %llu, attach new index block: %llu\n",
+	     (unsigned long long)OCFS2_I(dir)->ip_blkno,
+	     (unsigned long long)dr_blkno);
+
+	dx_root_bh = sb_getblk(osb->sb, dr_blkno);
+	if (dx_root_bh == NULL) {
+		ret = -EIO;
+		goto out;
+	}
+	ocfs2_set_new_buffer_uptodate(dir, dx_root_bh);
+
+	ret = ocfs2_journal_access_dr(handle, dir, dx_root_bh,
+				      OCFS2_JOURNAL_ACCESS_CREATE);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
+	memset(dx_root, 0, osb->sb->s_blocksize);
+	strcpy(dx_root->dr_signature, OCFS2_DX_ROOT_SIGNATURE);
+	dx_root->dr_suballoc_slot = cpu_to_le16(osb->slot_num);
+	dx_root->dr_suballoc_bit = cpu_to_le16(dr_suballoc_bit);
+	dx_root->dr_fs_generation = cpu_to_le32(osb->fs_generation);
+	dx_root->dr_blkno = cpu_to_le64(dr_blkno);
+	dx_root->dr_dir_blkno = cpu_to_le64(OCFS2_I(dir)->ip_blkno);
+	dx_root->dr_list.l_count =
+		cpu_to_le16(ocfs2_extent_recs_per_dx_root(osb->sb));
+
+	ret = ocfs2_journal_dirty(handle, dx_root_bh);
+	if (ret)
+		mlog_errno(ret);
+
+	ret = ocfs2_journal_access_di(handle, dir, di_bh,
+				      OCFS2_JOURNAL_ACCESS_CREATE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	di->i_dx_root = cpu_to_le64(dr_blkno);
+
+	OCFS2_I(dir)->ip_dyn_features |= OCFS2_INDEXED_DIR_FL;
+	di->i_dyn_features = cpu_to_le16(OCFS2_I(dir)->ip_dyn_features);
+
+	ret = ocfs2_journal_dirty(handle, di_bh);
+	if (ret)
+		mlog_errno(ret);
+
+	*ret_dx_root_bh = dx_root_bh;
+	dx_root_bh = NULL;
+
+out:
+	brelse(dx_root_bh);
+	return ret;
+}
+
+static int ocfs2_dx_dir_format_cluster(struct ocfs2_super *osb,
+				       handle_t *handle, struct inode *dir,
+				       struct buffer_head **dx_leaves,
+				       int num_dx_leaves, u64 start_blk)
+{
+	int ret, i;
+	struct ocfs2_dx_leaf *dx_leaf;
+	struct buffer_head *bh;
+
+	for (i = 0; i < num_dx_leaves; i++) {
+		bh = sb_getblk(osb->sb, start_blk + i);
+		if (bh == NULL) {
+			ret = -EIO;
+			goto out;
+		}
+		dx_leaves[i] = bh;
+
+		ocfs2_set_new_buffer_uptodate(dir, bh);
+
+		ret = ocfs2_journal_access_dl(handle, dir, bh,
+					      OCFS2_JOURNAL_ACCESS_CREATE);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		dx_leaf = (struct ocfs2_dx_leaf *) bh->b_data;
+
+		memset(dx_leaf, 0, osb->sb->s_blocksize);
+		strcpy(dx_leaf->dl_signature, OCFS2_DX_LEAF_SIGNATURE);
+		dx_leaf->dl_fs_generation = cpu_to_le32(osb->fs_generation);
+		dx_leaf->dl_blkno = cpu_to_le64(bh->b_blocknr);
+		dx_leaf->dl_list.de_count =
+			cpu_to_le16(ocfs2_dx_entries_per_leaf(osb->sb));
+
+		mlog(0,
+		     "Dir %llu, format dx_leaf: %llu, entry count: %u\n",
+		     (unsigned long long)OCFS2_I(dir)->ip_blkno,
+		     (unsigned long long)bh->b_blocknr,
+		     le16_to_cpu(dx_leaf->dl_list.de_count));
+
+		ocfs2_journal_dirty(handle, bh);
+	}
+
+	ret = 0;
+out:
+	return ret;
+}
+
+/*
+ * Allocates and formats a new cluster for use in an indexed dir
+ * leaf. This version will not do the extent insert, so that it can be
+ * used by operations which need careful ordering.
+ */
+static int __ocfs2_dx_dir_new_cluster(struct inode *dir,
+				      u32 cpos, handle_t *handle,
+				      struct ocfs2_alloc_context *data_ac,
+				      struct buffer_head **dx_leaves,
+				      int num_dx_leaves, u64 *ret_phys_blkno)
+{
+	int ret;
+	u32 phys, num;
+	u64 phys_blkno;
+	struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
+
+	/*
+	 * XXX: For create, this should claim cluster for the index
+	 * *before* the unindexed insert so that we have a better
+	 * chance of contiguousness as the directory grows in number
+	 * of entries.
+	 */
+	ret = __ocfs2_claim_clusters(osb, handle, data_ac, 1, 1, &phys, &num);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Format the new cluster first. That way, we're inserting
+	 * valid data.
+	 */
+	phys_blkno = ocfs2_clusters_to_blocks(osb->sb, phys);
+	ret = ocfs2_dx_dir_format_cluster(osb, handle, dir, dx_leaves,
+					  num_dx_leaves, phys_blkno);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	*ret_phys_blkno = phys_blkno;
+out:
+	return ret;
+}
+
+static int ocfs2_dx_dir_new_cluster(struct inode *dir,
+				    struct ocfs2_extent_tree *et,
+				    u32 cpos, handle_t *handle,
+				    struct ocfs2_alloc_context *data_ac,
+				    struct ocfs2_alloc_context *meta_ac,
+				    struct buffer_head **dx_leaves,
+				    int num_dx_leaves)
+{
+	int ret;
+	u64 phys_blkno;
+	struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
+
+	ret = __ocfs2_dx_dir_new_cluster(dir, cpos, handle, data_ac, dx_leaves,
+					 num_dx_leaves, &phys_blkno);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_insert_extent(osb, handle, dir, et, cpos, phys_blkno, 1, 0,
+				  meta_ac);
+	if (ret)
+		mlog_errno(ret);
+out:
+	return ret;
+}
+
+static struct buffer_head **ocfs2_dx_dir_kmalloc_leaves(struct super_block *sb,
+							int *ret_num_leaves)
+{
+	int num_dx_leaves = ocfs2_clusters_to_blocks(sb, 1);
+	struct buffer_head **dx_leaves;
+
+	dx_leaves = kcalloc(num_dx_leaves, sizeof(struct buffer_head *),
+			    GFP_NOFS);
+	if (dx_leaves && ret_num_leaves)
+		*ret_num_leaves = num_dx_leaves;
+
+	return dx_leaves;
+}
+
+static int ocfs2_fill_new_dir_dx(struct ocfs2_super *osb,
+				 handle_t *handle,
+				 struct inode *parent,
+				 struct inode *inode,
+				 struct buffer_head *di_bh,
+				 struct ocfs2_alloc_context *data_ac,
+				 struct ocfs2_alloc_context *meta_ac)
+{
+	int ret, num_dx_leaves, i;
+	struct buffer_head *leaf_bh = NULL;
+	struct buffer_head *dx_root_bh = NULL;
+	struct buffer_head **dx_leaves = NULL;
+	struct ocfs2_extent_tree et;
+	struct ocfs2_dx_hinfo hinfo;
+	u64 insert_blkno;
+
+	dx_leaves = ocfs2_dx_dir_kmalloc_leaves(osb->sb, &num_dx_leaves);
+	if (!dx_leaves) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Our strategy is to create the directory as though it were
+	 * unindexed, then add the index block. This works with very
+	 * little complication since the state of a new directory is a
+	 * very well known quantity.
+	 *
+	 * Essentially, we have two dirents ("." and ".."), in the 1st
+	 * block which need indexing.
+	 */
+
+	ret = ocfs2_fill_new_dir_el(osb, handle, parent, inode, di_bh,
+				    data_ac, &leaf_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Allocate and format the index leaf first, before attaching
+	 * the index root. That way we're sure that the main bitmap
+	 * won't -enospc on us with a half-created dir index.
+	 *
+	 * The meta data allocation for our index block will not
+	 * -enospc on us unless there is a disk corruption.
+	 */
+
+	ret = __ocfs2_dx_dir_new_cluster(inode, 0, handle, data_ac, dx_leaves,
+					 num_dx_leaves, &insert_blkno);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_dx_dir_name_hash(inode, ".", 1, &hinfo);
+	i = ocfs2_dx_dir_hash_idx(osb, &hinfo);
+	ret = __ocfs2_dx_dir_leaf_insert(inode, handle, &hinfo,
+					 leaf_bh->b_blocknr, dx_leaves[i]);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_dx_dir_name_hash(inode, "..", 2, &hinfo);
+	i = ocfs2_dx_dir_hash_idx(osb, &hinfo);
+	ret = __ocfs2_dx_dir_leaf_insert(inode, handle, &hinfo,
+					 leaf_bh->b_blocknr, dx_leaves[i]);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_dx_dir_attach_index(osb, handle, inode, di_bh, meta_ac,
+					&dx_root_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/* This should never fail considering we start with an empty
+	 * dx_root. */
+	ocfs2_init_dx_root_extent_tree(&et, inode, dx_root_bh);
+	ret = ocfs2_insert_extent(osb, handle, inode, &et, 0,
+				  insert_blkno, 1, 0, NULL);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	if (dx_leaves) {
+		for (i = 0; i < num_dx_leaves; i++)
+			brelse(dx_leaves[i]);
+		kfree(dx_leaves);
+	}
+	brelse(dx_root_bh);
+	brelse(leaf_bh);
+	return ret;
+}
+
 int ocfs2_fill_new_dir(struct ocfs2_super *osb,
 		       handle_t *handle,
 		       struct inode *parent,
 		       struct inode *inode,
 		       struct buffer_head *fe_bh,
-		       struct ocfs2_alloc_context *data_ac)
+		       struct ocfs2_alloc_context *data_ac,
+		       struct ocfs2_alloc_context *meta_ac)
+
 {
 	BUG_ON(!ocfs2_supports_inline_data(osb) && data_ac == NULL);
 
 	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
 		return ocfs2_fill_new_dir_id(osb, handle, parent, inode, fe_bh);
 
+	if (ocfs2_supports_indexed_dirs(osb))
+		return ocfs2_fill_new_dir_dx(osb, handle, parent, inode, fe_bh,
+					     data_ac, meta_ac);
+
 	return ocfs2_fill_new_dir_el(osb, handle, parent, inode, fe_bh,
-				     data_ac);
+				     data_ac, NULL);
+}
+
+static int ocfs2_dx_dir_index_block(struct inode *dir,
+				    handle_t *handle,
+				    struct buffer_head **dx_leaves,
+				    int num_dx_leaves,
+				    struct buffer_head *dirent_bh)
+{
+	int ret, namelen, i;
+	char *de_buf, *limit;
+	struct ocfs2_dir_entry *de;
+	struct buffer_head *dx_leaf_bh;
+	struct ocfs2_dx_hinfo hinfo;
+	u64 dirent_blk = dirent_bh->b_blocknr;
+
+	de_buf = dirent_bh->b_data;
+	limit = de_buf + dir->i_sb->s_blocksize;
+
+	while (de_buf < limit) {
+		de = (struct ocfs2_dir_entry *)de_buf;
+
+		namelen = de->name_len;
+		if (!namelen || !de->inode)
+			goto inc;
+
+		ocfs2_dx_dir_name_hash(dir, de->name, namelen, &hinfo);
+
+		i = ocfs2_dx_dir_hash_idx(OCFS2_SB(dir->i_sb), &hinfo);
+		dx_leaf_bh = dx_leaves[i];
+
+		ret = __ocfs2_dx_dir_leaf_insert(dir, handle, &hinfo,
+						 dirent_blk, dx_leaf_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+inc:
+		de_buf += le16_to_cpu(de->rec_len);
+	}
+
+out:
+	return ret;
 }
 
 /*
@@ -1401,29 +2437,57 @@ static void ocfs2_expand_last_dirent(char *start, unsigned int old_size,
  */
 static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 				   unsigned int blocks_wanted,
+				   struct ocfs2_dir_lookup_result *lookup,
 				   struct buffer_head **first_block_bh)
 {
-	u32 alloc, bit_off, len;
+	u32 alloc, dx_alloc, bit_off, len;
 	struct super_block *sb = dir->i_sb;
-	int ret, credits = ocfs2_inline_to_extents_credits(sb);
-	u64 blkno, bytes = blocks_wanted << sb->s_blocksize_bits;
+	int ret, i, num_dx_leaves = 0,
+		credits = ocfs2_inline_to_extents_credits(sb);
+	u64 dx_insert_blkno, blkno,
+		bytes = blocks_wanted << sb->s_blocksize_bits;
 	struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
 	struct ocfs2_inode_info *oi = OCFS2_I(dir);
 	struct ocfs2_alloc_context *data_ac;
+	struct ocfs2_alloc_context *meta_ac = NULL;
 	struct buffer_head *dirdata_bh = NULL;
+	struct buffer_head *dx_root_bh = NULL;
+	struct buffer_head **dx_leaves = NULL;
 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
 	handle_t *handle;
 	struct ocfs2_extent_tree et;
-	int did_quota = 0;
+	struct ocfs2_extent_tree dx_et;
+	int did_quota = 0, bytes_allocated = 0;
 
 	ocfs2_init_dinode_extent_tree(&et, dir, di_bh);
 
 	alloc = ocfs2_clusters_for_bytes(sb, bytes);
+	dx_alloc = 0;
+
+	if (ocfs2_supports_indexed_dirs(osb)) {
+		/* Add one more cluster for an index leaf */
+		dx_alloc++;
+		credits += ocfs2_add_dir_index_credits(sb);
+
+		dx_leaves = ocfs2_dx_dir_kmalloc_leaves(sb, &num_dx_leaves);
+		if (!dx_leaves) {
+			ret = -ENOMEM;
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/* This gets us the dx_root */
+		ret = ocfs2_reserve_new_metadata_blocks(osb, 1, &meta_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
 
 	/*
-	 * We should never need more than 2 clusters for this -
-	 * maximum dirent size is far less than one block. In fact,
-	 * the only time we'd need more than one cluster is if
+	 * We should never need more than 2 clusters for the unindexed
+	 * tree - maximum dirent size is far less than one block. In
+	 * fact, the only time we'd need more than one cluster is if
 	 * blocksize == clustersize and the dirent won't fit in the
 	 * extra space that the expansion to a single block gives. As
 	 * of today, that only happens on 4k/4k file systems.
@@ -1440,7 +2504,7 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 
 	/*
 	 * Prepare for worst case allocation scenario of two separate
-	 * extents.
+	 * extents in the unindexed tree.
 	 */
 	if (alloc == 2)
 		credits += OCFS2_SUBALLOC_ALLOC;
@@ -1453,11 +2517,29 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 	}
 
 	if (vfs_dq_alloc_space_nodirty(dir,
-				ocfs2_clusters_to_bytes(osb->sb, alloc))) {
+				ocfs2_clusters_to_bytes(osb->sb,
+							alloc + dx_alloc))) {
 		ret = -EDQUOT;
 		goto out_commit;
 	}
 	did_quota = 1;
+
+	if (ocfs2_supports_indexed_dirs(osb)) {
+		/*
+		 * Allocate our index cluster first, to maximize the
+		 * possibility that unindexed leaves grow
+		 * contiguously.
+		 */
+		ret = __ocfs2_dx_dir_new_cluster(dir, 0, handle, data_ac,
+						 dx_leaves, num_dx_leaves,
+						 &dx_insert_blkno);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_commit;
+		}
+		bytes_allocated += ocfs2_clusters_to_bytes(dir->i_sb, 1);
+	}
+
 	/*
 	 * Try to claim as many clusters as the bitmap can give though
 	 * if we only get one now, that's enough to continue. The rest
@@ -1468,6 +2550,7 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 		mlog_errno(ret);
 		goto out_commit;
 	}
+	bytes_allocated += ocfs2_clusters_to_bytes(dir->i_sb, 1);
 
 	/*
 	 * Operations are carefully ordered so that we set up the new
@@ -1504,6 +2587,15 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 		goto out_commit;
 	}
 
+	if (ocfs2_supports_indexed_dirs(osb)) {
+		ret = ocfs2_dx_dir_index_block(dir, handle, dx_leaves,
+					       num_dx_leaves, dirdata_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_commit;
+		}
+	}
+
 	/*
 	 * Set extent, i_size, etc on the directory. After this, the
 	 * inode should contain the same exact dirents as before and
@@ -1556,6 +2648,21 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 		goto out_commit;
 	}
 
+	if (ocfs2_supports_indexed_dirs(osb)) {
+		ret = ocfs2_dx_dir_attach_index(osb, handle, dir, di_bh,
+						meta_ac, &dx_root_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_commit;
+		}
+
+		ocfs2_init_dx_root_extent_tree(&dx_et, dir, dx_root_bh);
+		ret = ocfs2_insert_extent(osb, handle, dir, &dx_et, 0,
+					  dx_insert_blkno, 1, 0, NULL);
+		if (ret)
+			mlog_errno(ret);
+	}
+
 	/*
 	 * We asked for two clusters, but only got one in the 1st
 	 * pass. Claim the 2nd cluster as a separate extent.
@@ -1575,15 +2682,28 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 			mlog_errno(ret);
 			goto out_commit;
 		}
+		bytes_allocated += ocfs2_clusters_to_bytes(dir->i_sb, 1);
 	}
 
 	*first_block_bh = dirdata_bh;
 	dirdata_bh = NULL;
+	if (ocfs2_supports_indexed_dirs(osb)) {
+		unsigned int off;
+
+		/*
+		 * We need to return the correct block within the
+		 * cluster which should hold our entry.
+		 */
+		off = ocfs2_dx_dir_hash_idx(OCFS2_SB(dir->i_sb),
+					    &lookup->dl_hinfo);
+		get_bh(dx_leaves[off]);
+		lookup->dl_dx_leaf_bh = dx_leaves[off];
+	}
 
 out_commit:
 	if (ret < 0 && did_quota)
-		vfs_dq_free_space_nodirty(dir,
-			ocfs2_clusters_to_bytes(osb->sb, 2));
+		vfs_dq_free_space_nodirty(dir, bytes_allocated);
+
 	ocfs2_commit_trans(osb, handle);
 
 out_sem:
@@ -1592,8 +2712,17 @@ out_sem:
 out:
 	if (data_ac)
 		ocfs2_free_alloc_context(data_ac);
+	if (meta_ac)
+		ocfs2_free_alloc_context(meta_ac);
+
+	if (dx_leaves) {
+		for (i = 0; i < num_dx_leaves; i++)
+			brelse(dx_leaves[i]);
+		kfree(dx_leaves);
+	}
 
 	brelse(dirdata_bh);
+	brelse(dx_root_bh);
 
 	return ret;
 }
@@ -1668,6 +2797,7 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
 			    struct inode *dir,
 			    struct buffer_head *parent_fe_bh,
 			    unsigned int blocks_wanted,
+			    struct ocfs2_dir_lookup_result *lookup,
 			    struct buffer_head **new_de_bh)
 {
 	int status = 0;
@@ -1687,7 +2817,8 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
 
 	if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 		status = ocfs2_expand_inline_dir(dir, parent_fe_bh,
-						 blocks_wanted, &new_bh);
+						 blocks_wanted, lookup,
+						 &new_bh);
 		if (status) {
 			mlog_errno(status);
 			goto bail;
@@ -1975,6 +3106,487 @@ bail:
 	return status;
 }
 
+static int dx_leaf_sort_cmp(const void *a, const void *b)
+{
+	const struct ocfs2_dx_entry *entry1 = a;
+	const struct ocfs2_dx_entry *entry2 = b;
+	u32 major_hash1 = le32_to_cpu(entry1->dx_major_hash);
+	u32 major_hash2 = le32_to_cpu(entry2->dx_major_hash);
+	u32 minor_hash1 = le32_to_cpu(entry1->dx_minor_hash);
+	u32 minor_hash2 = le32_to_cpu(entry2->dx_minor_hash);
+
+	if (major_hash1 > major_hash2)
+		return 1;
+	if (major_hash1 < major_hash2)
+		return -1;
+
+	/*
+	 * It is not strictly necessary to sort by minor
+	 */
+	if (minor_hash1 > minor_hash2)
+		return 1;
+	if (minor_hash1 < minor_hash2)
+		return -1;
+	return 0;
+}
+
+static void dx_leaf_sort_swap(void *a, void *b, int size)
+{
+	struct ocfs2_dx_entry *entry1 = a;
+	struct ocfs2_dx_entry *entry2 = b;
+	struct ocfs2_dx_entry tmp;
+
+	BUG_ON(size != sizeof(*entry1));
+
+	tmp = *entry1;
+	*entry1 = *entry2;
+	*entry2 = tmp;
+}
+
+static int ocfs2_dx_leaf_same_major(struct ocfs2_dx_leaf *dx_leaf)
+{
+	struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
+	int i, num = le16_to_cpu(dl_list->de_num_used);
+
+	for (i = 0; i < (num - 1); i++) {
+		if (le32_to_cpu(dl_list->de_entries[i].dx_major_hash) !=
+		    le32_to_cpu(dl_list->de_entries[i + 1].dx_major_hash))
+			return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Find the optimal value to split this leaf on. This expects the leaf
+ * entries to be in sorted order.
+ *
+ * leaf_cpos is the cpos of the leaf we're splitting. insert_hash is
+ * the hash we want to insert.
+ *
+ * This function is only concerned with the major hash - that which
+ * determines which cluster an item belongs to.
+ */
+static int ocfs2_dx_dir_find_leaf_split(struct ocfs2_dx_leaf *dx_leaf,
+					u32 leaf_cpos, u32 insert_hash,
+					u32 *split_hash)
+{
+	struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
+	int i, num_used = le16_to_cpu(dl_list->de_num_used);
+	int allsame;
+
+	/*
+	 * There's a couple rare, but nasty corner cases we have to
+	 * check for here. All of them involve a leaf where all value
+	 * have the same hash, which is what we look for first.
+	 *
+	 * Most of the time, all of the above is false, and we simply
+	 * pick the median value for a split.
+	 */
+	allsame = ocfs2_dx_leaf_same_major(dx_leaf);
+	if (allsame) {
+		u32 val = le32_to_cpu(dl_list->de_entries[0].dx_major_hash);
+
+		if (val == insert_hash) {
+			/*
+			 * No matter where we would choose to split,
+			 * the new entry would want to occupy the same
+			 * block as these. Since there's no space left
+			 * in their existing block, we know there
+			 * won't be space after the split.
+			 */
+			return -ENOSPC;
+		}
+
+		if (val == leaf_cpos) {
+			/*
+			 * Because val is the same as leaf_cpos (which
+			 * is the smallest value this leaf can have),
+			 * yet is not equal to insert_hash, then we
+			 * know that insert_hash *must* be larger than
+			 * val (and leaf_cpos). At least cpos+1 in value.
+			 *
+			 * We also know then, that there cannot be an
+			 * adjacent extent (otherwise we'd be looking
+			 * at it). Choosing this value gives us a
+			 * chance to get some contiguousness.
+			 */
+			*split_hash = leaf_cpos + 1;
+			return 0;
+		}
+
+		if (val > insert_hash) {
+			/*
+			 * val can not be the same as insert hash, and
+			 * also must be larger than leaf_cpos. Also,
+			 * we know that there can't be a leaf between
+			 * cpos and val, otherwise the entries with
+			 * hash 'val' would be there.
+			 */
+			*split_hash = val;
+			return 0;
+		}
+
+		*split_hash = insert_hash;
+		return 0;
+	}
+
+	/*
+	 * Since the records are sorted and the checks above
+	 * guaranteed that not all records in this block are the same,
+	 * we simple travel forward, from the median, and pick the 1st
+	 * record whose value is larger than leaf_cpos.
+	 */
+	for (i = (num_used / 2); i < num_used; i++)
+		if (le32_to_cpu(dl_list->de_entries[i].dx_major_hash) >
+		    leaf_cpos)
+			break;
+
+	BUG_ON(i == num_used); /* Should be impossible */
+	*split_hash = le32_to_cpu(dl_list->de_entries[i].dx_major_hash);
+	return 0;
+}
+
+/*
+ * Transfer all entries in orig_dx_leaves whose major hash is equal to or
+ * larger than split_hash into new_dx_leaves. We use a temporary
+ * buffer (tmp_dx_leaf) to make the changes to the original leaf blocks.
+ *
+ * Since the block offset inside a leaf (cluster) is a constant mask
+ * of minor_hash, we can optimize - an item at block offset X within
+ * the original cluster, will be at offset X within the new cluster.
+ */
+static void ocfs2_dx_dir_transfer_leaf(struct inode *dir, u32 split_hash,
+				       handle_t *handle,
+				       struct ocfs2_dx_leaf *tmp_dx_leaf,
+				       struct buffer_head **orig_dx_leaves,
+				       struct buffer_head **new_dx_leaves,
+				       int num_dx_leaves)
+{
+	int i, j, num_used;
+	u32 major_hash;
+	struct ocfs2_dx_leaf *orig_dx_leaf, *new_dx_leaf;
+	struct ocfs2_dx_entry_list *orig_list, *new_list, *tmp_list;
+	struct ocfs2_dx_entry *dx_entry;
+
+	tmp_list = &tmp_dx_leaf->dl_list;
+
+	for (i = 0; i < num_dx_leaves; i++) {
+		orig_dx_leaf = (struct ocfs2_dx_leaf *) orig_dx_leaves[i]->b_data;
+		orig_list = &orig_dx_leaf->dl_list;
+		new_dx_leaf = (struct ocfs2_dx_leaf *) new_dx_leaves[i]->b_data;
+		new_list = &new_dx_leaf->dl_list;
+
+		num_used = le16_to_cpu(orig_list->de_num_used);
+
+		memcpy(tmp_dx_leaf, orig_dx_leaf, dir->i_sb->s_blocksize);
+		tmp_list->de_num_used = cpu_to_le16(0);
+		memset(&tmp_list->de_entries, 0, sizeof(*dx_entry)*num_used);
+
+		for (j = 0; j < num_used; j++) {
+			dx_entry = &orig_list->de_entries[j];
+			major_hash = le32_to_cpu(dx_entry->dx_major_hash);
+			if (major_hash >= split_hash)
+				ocfs2_dx_dir_leaf_insert_tail(new_dx_leaf,
+							      dx_entry);
+			else
+				ocfs2_dx_dir_leaf_insert_tail(tmp_dx_leaf,
+							      dx_entry);
+		}
+		memcpy(orig_dx_leaf, tmp_dx_leaf, dir->i_sb->s_blocksize);
+
+		ocfs2_journal_dirty(handle, orig_dx_leaves[i]);
+		ocfs2_journal_dirty(handle, new_dx_leaves[i]);
+	}
+}
+
+static int ocfs2_dx_dir_rebalance_credits(struct ocfs2_super *osb,
+					  struct ocfs2_dx_root_block *dx_root)
+{
+	int credits = ocfs2_clusters_to_blocks(osb->sb, 2);
+
+	credits += ocfs2_calc_extend_credits(osb->sb, &dx_root->dr_list, 1);
+	credits += ocfs2_quota_trans_credits(osb->sb);
+	return credits;
+}
+
+/*
+ * Find the median value in dx_leaf_bh and allocate a new leaf to move
+ * half our entries into.
+ */
+static int ocfs2_dx_dir_rebalance(struct ocfs2_super *osb, struct inode *dir,
+				  struct buffer_head *dx_root_bh,
+				  struct buffer_head *dx_leaf_bh,
+				  struct ocfs2_dx_hinfo *hinfo, u32 leaf_cpos,
+				  u64 leaf_blkno)
+{
+	struct ocfs2_dx_leaf *dx_leaf = (struct ocfs2_dx_leaf *)dx_leaf_bh->b_data;
+	int credits, ret, i, num_used, did_quota = 0;
+	u32 cpos, split_hash, insert_hash = hinfo->major_hash;
+	u64 orig_leaves_start;
+	int num_dx_leaves;
+	struct buffer_head **orig_dx_leaves = NULL;
+	struct buffer_head **new_dx_leaves = NULL;
+	struct ocfs2_alloc_context *data_ac = NULL, *meta_ac = NULL;
+	struct ocfs2_extent_tree et;
+	handle_t *handle = NULL;
+	struct ocfs2_dx_root_block *dx_root;
+	struct ocfs2_dx_leaf *tmp_dx_leaf = NULL;
+
+	mlog(0, "DX Dir: %llu, rebalance leaf leaf_blkno: %llu insert: %u\n",
+	     (unsigned long long)OCFS2_I(dir)->ip_blkno,
+	     (unsigned long long)leaf_blkno, insert_hash);
+
+	ocfs2_init_dx_root_extent_tree(&et, dir, dx_root_bh);
+
+	dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
+	/*
+	 * XXX: This is a rather large limit. We should use a more
+	 * realistic value.
+	 */
+	if (le32_to_cpu(dx_root->dr_clusters) == UINT_MAX)
+		return -ENOSPC;
+
+	num_used = le16_to_cpu(dx_leaf->dl_list.de_num_used);
+	if (num_used < le16_to_cpu(dx_leaf->dl_list.de_count)) {
+		mlog(ML_ERROR, "DX Dir: %llu, Asked to rebalance empty leaf: "
+		     "%llu, %d\n", (unsigned long long)OCFS2_I(dir)->ip_blkno,
+		     (unsigned long long)leaf_blkno, num_used);
+		ret = -EIO;
+		goto out;
+	}
+
+	orig_dx_leaves = ocfs2_dx_dir_kmalloc_leaves(osb->sb, &num_dx_leaves);
+	if (!orig_dx_leaves) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	new_dx_leaves = ocfs2_dx_dir_kmalloc_leaves(osb->sb, NULL);
+	if (!new_dx_leaves) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_lock_allocators(dir, &et, 1, 0, &data_ac, &meta_ac);
+	if (ret) {
+		if (ret != -ENOSPC)
+			mlog_errno(ret);
+		goto out;
+	}
+
+	credits = ocfs2_dx_dir_rebalance_credits(osb, dx_root);
+	handle = ocfs2_start_trans(osb, credits);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		handle = NULL;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (vfs_dq_alloc_space_nodirty(dir,
+				       ocfs2_clusters_to_bytes(dir->i_sb, 1))) {
+		ret = -EDQUOT;
+		goto out_commit;
+	}
+	did_quota = 1;
+
+	ret = ocfs2_journal_access_dl(handle, dir, dx_leaf_bh,
+				      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	/*
+	 * This block is changing anyway, so we can sort it in place.
+	 */
+	sort(dx_leaf->dl_list.de_entries, num_used,
+	     sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp,
+	     dx_leaf_sort_swap);
+
+	ret = ocfs2_journal_dirty(handle, dx_leaf_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	ret = ocfs2_dx_dir_find_leaf_split(dx_leaf, leaf_cpos, insert_hash,
+					   &split_hash);
+	if (ret) {
+		mlog_errno(ret);
+		goto  out_commit;
+	}
+
+	mlog(0, "Split leaf (%u) at %u, insert major hash is %u\n",
+	     leaf_cpos, split_hash, insert_hash);
+
+	/*
+	 * We have to carefully order operations here. There are items
+	 * which want to be in the new cluster before insert, but in
+	 * order to put those items in the new cluster, we alter the
+	 * old cluster. A failure to insert gets nasty.
+	 *
+	 * So, start by reserving writes to the old
+	 * cluster. ocfs2_dx_dir_new_cluster will reserve writes on
+	 * the new cluster for us, before inserting it. The insert
+	 * won't happen if there's an error before that. Once the
+	 * insert is done then, we can transfer from one leaf into the
+	 * other without fear of hitting any error.
+	 */
+
+	/*
+	 * The leaf transfer wants some scratch space so that we don't
+	 * wind up doing a bunch of expensive memmove().
+	 */
+	tmp_dx_leaf = kmalloc(osb->sb->s_blocksize, GFP_NOFS);
+	if (!tmp_dx_leaf) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	orig_leaves_start = leaf_blkno & ~(osb->s_clustersize_bits -
+				      osb->sb->s_blocksize_bits);
+	ret = ocfs2_read_dx_leaves(dir, orig_leaves_start, num_dx_leaves,
+				   orig_dx_leaves);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	for (i = 0; i < num_dx_leaves; i++) {
+		ret = ocfs2_journal_access_dl(handle, dir, orig_dx_leaves[i],
+					      OCFS2_JOURNAL_ACCESS_WRITE);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_commit;
+		}
+	}
+
+	cpos = split_hash;
+	ret = ocfs2_dx_dir_new_cluster(dir, &et, cpos, handle,
+				       data_ac, meta_ac, new_dx_leaves,
+				       num_dx_leaves);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	ocfs2_dx_dir_transfer_leaf(dir, split_hash, handle, tmp_dx_leaf,
+				   orig_dx_leaves, new_dx_leaves, num_dx_leaves);
+
+out_commit:
+	if (ret < 0 && did_quota)
+		vfs_dq_free_space_nodirty(dir,
+				ocfs2_clusters_to_bytes(dir->i_sb, 1));
+
+	ocfs2_commit_trans(osb, handle);
+
+out:
+	if (orig_dx_leaves || new_dx_leaves) {
+		for (i = 0; i < num_dx_leaves; i++) {
+			if (orig_dx_leaves)
+				brelse(orig_dx_leaves[i]);
+			if (new_dx_leaves)
+				brelse(new_dx_leaves[i]);
+		}
+		kfree(orig_dx_leaves);
+		kfree(new_dx_leaves);
+	}
+
+	if (meta_ac)
+		ocfs2_free_alloc_context(meta_ac);
+	if (data_ac)
+		ocfs2_free_alloc_context(data_ac);
+
+	kfree(tmp_dx_leaf);
+	return ret;
+}
+
+static int ocfs2_find_dir_space_dx(struct ocfs2_super *osb, struct inode *dir,
+				   struct buffer_head *di_bh, const char *name,
+				   int namelen,
+				   struct ocfs2_dir_lookup_result *lookup)
+{
+	int ret, rebalanced = 0;
+	struct buffer_head *dx_root_bh = NULL;
+	struct ocfs2_dx_root_block *dx_root;
+	struct buffer_head *dx_leaf_bh = NULL;
+	struct ocfs2_dx_leaf *dx_leaf;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	u64 blkno;
+	u32 leaf_cpos;
+
+	ret = ocfs2_read_dx_root(dir, di, &dx_root_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
+
+restart_search:
+	ret = ocfs2_dx_dir_lookup(dir, &dx_root->dr_list, &lookup->dl_hinfo,
+				  &leaf_cpos, &blkno);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_read_dx_leaf(dir, blkno, &dx_leaf_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	dx_leaf = (struct ocfs2_dx_leaf *)dx_leaf_bh->b_data;
+
+	if (le16_to_cpu(dx_leaf->dl_list.de_num_used) >=
+	    le16_to_cpu(dx_leaf->dl_list.de_count)) {
+		if (rebalanced) {
+			/*
+			 * Rebalancing should have provided us with
+			 * space in an appropriate leaf.
+			 *
+			 * XXX: Is this an abnormal condition then?
+			 * Should we print a message here?
+			 */
+			ret = -ENOSPC;
+			goto out;
+		}
+
+		ret = ocfs2_dx_dir_rebalance(osb, dir, dx_root_bh, dx_leaf_bh,
+					     &lookup->dl_hinfo, leaf_cpos,
+					     blkno);
+		if (ret) {
+			if (ret != -ENOSPC)
+				mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * Restart the lookup. The rebalance might have
+		 * changed which block our item fits into. Mark our
+		 * progress, so we only execute this once.
+		 */
+		brelse(dx_leaf_bh);
+		dx_leaf_bh = NULL;
+		rebalanced = 1;
+		goto restart_search;
+	}
+
+	lookup->dl_dx_leaf_bh = dx_leaf_bh;
+	dx_leaf_bh = NULL;
+
+out:
+	brelse(dx_leaf_bh);
+	brelse(dx_root_bh);
+	return ret;
+}
+
 /*
  * Get a directory ready for insert. Any directory allocation required
  * happens here. Success returns zero, and enough context in the dir
@@ -2001,6 +3613,34 @@ int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
 		goto out;
 	}
 
+	/*
+	 * Do this up front to reduce confusion.
+	 *
+	 * The directory might start inline, then be turned into an
+	 * indexed one, in which case we'd need to hash deep inside
+	 * ocfs2_find_dir_space_id(). Since
+	 * ocfs2_prepare_dx_dir_for_insert() also needs this hash
+	 * done, there seems no point in spreading out the calls. We
+	 * can optimize away the case where the file system doesn't
+	 * support indexing.
+	 */
+	if (ocfs2_supports_indexed_dirs(osb))
+		ocfs2_dx_dir_name_hash(dir, name, namelen, &lookup->dl_hinfo);
+
+	if (ocfs2_dir_indexed(dir)) {
+		ret = ocfs2_find_dir_space_dx(osb, dir, parent_fe_bh, name,
+					      namelen, lookup);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * We intentionally fall through so that the unindexed
+		 * tree can also be prepared.
+		 */
+	}
+
 	if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 		ret = ocfs2_find_dir_space_id(dir, parent_fe_bh, name,
 					      namelen, &bh, &blocks_wanted);
@@ -2019,7 +3659,7 @@ int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
 		BUG_ON(bh);
 
 		ret = ocfs2_extend_dir(osb, dir, parent_fe_bh, blocks_wanted,
-				       &bh);
+				       lookup, &bh);
 		if (ret) {
 			if (ret != -ENOSPC)
 				mlog_errno(ret);
@@ -2035,3 +3675,145 @@ out:
 	brelse(bh);
 	return ret;
 }
+
+static int ocfs2_dx_dir_remove_index(struct inode *dir,
+				     struct buffer_head *di_bh,
+				     struct buffer_head *dx_root_bh)
+{
+	int ret;
+	struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_dx_root_block *dx_root;
+	struct inode *dx_alloc_inode = NULL;
+	struct buffer_head *dx_alloc_bh = NULL;
+	handle_t *handle;
+	u64 blk;
+	u16 bit;
+	u64 bg_blkno;
+
+	dx_root = (struct ocfs2_dx_root_block *) dx_root_bh->b_data;
+
+	dx_alloc_inode = ocfs2_get_system_file_inode(osb,
+					EXTENT_ALLOC_SYSTEM_INODE,
+					le16_to_cpu(dx_root->dr_suballoc_slot));
+	if (!dx_alloc_inode) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+	mutex_lock(&dx_alloc_inode->i_mutex);
+
+	ret = ocfs2_inode_lock(dx_alloc_inode, &dx_alloc_bh, 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_mutex;
+	}
+
+	handle = ocfs2_start_trans(osb, OCFS2_DX_ROOT_REMOVE_CREDITS);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		mlog_errno(ret);
+		goto out_unlock;
+	}
+
+	ret = ocfs2_journal_access_di(handle, dir, di_bh,
+				      OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	OCFS2_I(dir)->ip_dyn_features &= ~OCFS2_INDEXED_DIR_FL;
+	di->i_dyn_features = cpu_to_le16(OCFS2_I(dir)->ip_dyn_features);
+	di->i_dx_root = cpu_to_le64(0ULL);
+
+	ocfs2_journal_dirty(handle, di_bh);
+
+	blk = le64_to_cpu(dx_root->dr_blkno);
+	bit = le16_to_cpu(dx_root->dr_suballoc_bit);
+	bg_blkno = ocfs2_which_suballoc_group(blk, bit);
+	ret = ocfs2_free_suballoc_bits(handle, dx_alloc_inode, dx_alloc_bh,
+				       bit, bg_blkno, 1);
+	if (ret)
+		mlog_errno(ret);
+
+out_commit:
+	ocfs2_commit_trans(osb, handle);
+
+out_unlock:
+	ocfs2_inode_unlock(dx_alloc_inode, 1);
+
+out_mutex:
+	mutex_unlock(&dx_alloc_inode->i_mutex);
+	brelse(dx_alloc_bh);
+out:
+	iput(dx_alloc_inode);
+	return ret;
+}
+
+int ocfs2_dx_dir_truncate(struct inode *dir, struct buffer_head *di_bh)
+{
+	int ret;
+	unsigned int uninitialized_var(clen);
+	u32 major_hash = UINT_MAX, p_cpos, uninitialized_var(cpos);
+	u64 uninitialized_var(blkno);
+	struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
+	struct buffer_head *dx_root_bh = NULL;
+	struct ocfs2_dx_root_block *dx_root;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_cached_dealloc_ctxt dealloc;
+	struct ocfs2_extent_tree et;
+
+	ocfs2_init_dealloc_ctxt(&dealloc);
+
+	if (!ocfs2_dir_indexed(dir))
+		return 0;
+
+	ret = ocfs2_read_dx_root(dir, di, &dx_root_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_init_dx_root_extent_tree(&et, dir, dx_root_bh);
+
+	dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
+
+	/* XXX: What if dr_clusters is too large? */
+	while (le32_to_cpu(dx_root->dr_clusters)) {
+		ret = ocfs2_dx_dir_lookup_rec(dir, &dx_root->dr_list,
+					      major_hash, &cpos, &blkno, &clen);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		p_cpos = ocfs2_blocks_to_clusters(dir->i_sb, blkno);
+
+		ret = ocfs2_remove_btree_range(dir, &et, cpos, p_cpos, clen,
+					       &dealloc);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (cpos == 0)
+			break;
+
+		major_hash = cpos - 1;
+	}
+
+	ret = ocfs2_dx_dir_remove_index(dir, di_bh, dx_root_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_remove_from_cache(dir, dx_root_bh);
+out:
+	ocfs2_schedule_truncate_log_flush(osb, 1);
+	ocfs2_run_deallocs(osb, &dealloc);
+
+	brelse(dx_root_bh);
+	return ret;
+}