Add initial support in debugfs for examining directory indexing
information.

diff --git a/debugfs/ChangeLog b/debugfs/ChangeLog
index 1cff0b0..4d8a301 100644
--- a/debugfs/ChangeLog
+++ b/debugfs/ChangeLog
@@ -1,3 +1,12 @@
+2002-02-25  Theodore Tso  <tytso@valinux.com>
+
+	* util.c (open_pager): If the PAGER environment is set to __none__
+		then don't use a pager at all, and ship it all to stdout.
+
+	* Makefile.in, debug_cmds.ct, htree.c: Add new file htree.c, which
+		implements the three new commands, htree_dump, dx_hash,
+		and dirsearch.
+
 2002-02-24  Theodore Tso  <tytso@valinux.com>
 
 	* Makefile.in (install): Remove any compressed man pages before
diff --git a/debugfs/Makefile.in b/debugfs/Makefile.in
index 79ae78e..b76dec2 100644
--- a/debugfs/Makefile.in
+++ b/debugfs/Makefile.in
@@ -17,11 +17,12 @@
 MK_CMDS=	_SS_DIR_OVERRIDE=../lib/ss ../lib/ss/mk_cmds
 
 DEBUG_OBJS= debug_cmds.o debugfs.o util.o ncheck.o icheck.o ls.o \
-	lsdel.o dump.o setsuper.o logdump.o
+	lsdel.o dump.o setsuper.o logdump.o htree.o
 
 SRCS= debug_cmds.c $(srcdir)/debugfs.c $(srcdir)/util.c $(srcdir)/ls.c \
 	$(srcdir)/ncheck.c $(srcdir)/icheck.c $(srcdir)/lsdel.c \
-	$(srcdir)/dump.c $(srcdir)/setsuper.c ${srcdir}/logdump.c
+	$(srcdir)/dump.c $(srcdir)/setsuper.c ${srcdir}/logdump.c \
+	$(srcdir)/htree.c
 
 LIBS= $(LIBEXT2FS) $(LIBE2P) $(LIBSS) $(LIBCOM_ERR)  $(LIBUUID)
 DEPLIBS= $(LIBEXT2FS) $(LIBE2P) $(LIBSS) $(LIBCOM_ERR)  $(DEPLIBUUID)
diff --git a/debugfs/debug_cmds.ct b/debugfs/debug_cmds.ct
index 63f9c0a..96d972e 100644
--- a/debugfs/debug_cmds.ct
+++ b/debugfs/debug_cmds.ct
@@ -127,5 +127,14 @@
 request do_logdump, "Dump the contents of the journal",
 	logdump;
 
+request do_htree_dump, "Dump a hash-indexed directory",
+	htree_dump, htree;
+
+request do_dx_hash, "Calculate the directory hash of a filename",
+	dx_hash, hash;
+
+request do_dirsearch, "Search a directory for a particular filename",
+	dirsearch;
+
 end;
 
diff --git a/debugfs/htree.c b/debugfs/htree.c
new file mode 100644
index 0000000..86909a7
--- /dev/null
+++ b/debugfs/htree.c
@@ -0,0 +1,364 @@
+/*
+ * htree.c --- hash tree routines
+ * 
+ * Copyright (C) 2002 Theodore Ts'o.  This file may be redistributed
+ * under the terms of the GNU Public License.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <time.h>
+#ifdef HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <sys/types.h>
+#ifdef HAVE_GETOPT_H
+#include <getopt.h>
+#else 
+extern int optind;
+extern char *optarg;
+#endif
+#ifdef HAVE_OPTRESET
+extern int optreset;		/* defined by BSD, but not others */
+#endif
+
+#include "debugfs.h"
+
+static FILE *pager;
+
+static unsigned dx_hack_hash (const char *name, int len)
+{
+	__u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+	while (len--) {
+		__u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
+		
+		if (hash & 0x80000000) hash -= 0x7fffffff;
+		hash1 = hash0;
+		hash0 = hash;
+	}
+	return hash0;
+}
+
+#define dx_hash(s,n) (dx_hack_hash(s,n) << 1)
+
+static void htree_dump_leaf_node(ext2_filsys fs, ext2_ino_t ino,
+				 struct ext2_inode *inode,
+				 blk_t blk, char *buf)
+{
+	errcode_t	errcode;
+	struct ext2_dir_entry *dirent;
+	int		thislen, col = 0, offset = 0;
+	char		name[EXT2_NAME_LEN];
+	char		tmp[EXT2_NAME_LEN + 16];
+	blk_t		pblk;
+	
+	errcode = ext2fs_bmap(fs, ino, inode, buf, 0, blk, &pblk);
+	if (errcode) {
+		com_err("htree_dump_leaf_node", errcode,
+			"while mapping logical block %d\n", blk);
+		return;
+	}
+
+	errcode = io_channel_read_blk(current_fs->io, pblk, 1, buf);
+	if (errcode) {
+		com_err("htree_dump_leaf_node", errcode,
+			"while 	reading block %d\n", blk);
+		return;
+	}
+
+	while (offset < fs->blocksize) {
+		dirent = (struct ext2_dir_entry *) (buf + offset);
+		if (((offset + dirent->rec_len) > fs->blocksize) ||
+		    (dirent->rec_len < 8) ||
+		    ((dirent->rec_len % 4) != 0) ||
+		    (((dirent->name_len & 0xFF)+8) > dirent->rec_len)) {
+			fprintf(pager, "Corrupted directory block (%d)!\n", blk);
+			break;
+		}
+		thislen = ((dirent->name_len & 0xFF) < EXT2_NAME_LEN) ?
+			(dirent->name_len & 0xFF) : EXT2_NAME_LEN;
+		strncpy(name, dirent->name, thislen);
+		name[thislen] = '\0';
+		sprintf(tmp, "%u 0x%08x (%d) %s   ", dirent->inode,
+		       dx_hash(name, thislen), dirent->rec_len, name);
+		thislen = strlen(tmp);
+		if (col + thislen > 80) {
+			fprintf(pager, "\n");
+			col = 0;
+		}
+		fprintf(pager, "%s", tmp);
+		col += thislen;
+		offset += dirent->rec_len;
+	}
+	fprintf(pager, "\n");
+}
+
+
+static void htree_dump_int_block(ext2_filsys fs, ext2_ino_t ino,
+				 struct ext2_inode *inode,
+				 blk_t blk, char *buf, int level);
+
+
+static void htree_dump_int_node(ext2_filsys fs, ext2_ino_t ino,
+				struct ext2_inode *inode,
+				struct ext2_dx_entry *ent, 
+				char *buf, int level)
+{
+	struct		ext2_dx_countlimit *limit;
+	int		i;
+
+	limit = (struct ext2_dx_countlimit *) ent;
+
+	fprintf(pager, "Number of entries (count): %d\n", limit->count);
+	fprintf(pager, "Number of entries (limit): %d\n", limit->limit);
+
+	for (i=0; i < limit->count; i++)
+		fprintf(pager, "Entry #%d: Hash 0x%08x, block %d\n", i,
+		       i ? ent[i].hash : 0, ent[i].block);
+
+	fprintf(pager, "\n");
+
+	for (i=0; i < limit->count; i++) {
+		fprintf(pager, "Entry #%d: Hash 0x%08x, block %d\n", i,
+		       i ? ent[i].hash : 0, ent[i].block);
+		if (level)
+			htree_dump_int_block(fs, ino, inode,
+					     ent[i].block, buf, level-1);
+		else
+			htree_dump_leaf_node(fs, ino, inode,
+					     ent[i].block, buf);
+	}
+
+	fprintf(pager, "---------------------\n");
+}
+
+static void htree_dump_int_block(ext2_filsys fs, ext2_ino_t ino,
+				 struct ext2_inode *inode,
+				 blk_t blk, char *buf, int level)
+{
+	char		*cbuf;
+	errcode_t	errcode;
+	blk_t		pblk;
+
+	cbuf = malloc(fs->blocksize);
+	if (!cbuf) {
+		fprintf(pager, "Couldn't allocate child block.\n");
+		return;
+	}
+	
+	errcode = ext2fs_bmap(fs, ino, inode, buf, 0, blk, &pblk);
+	if (errcode) {
+		com_err("htree_dump_int_block", errcode,
+			"while mapping logical block %d\n", blk);
+		return;
+	}
+
+	errcode = io_channel_read_blk(current_fs->io, pblk, 1, buf);
+	if (errcode) {
+		com_err("htree_dump_int_block", errcode,
+			"while 	reading block %d\n", blk);
+		return;
+	}
+
+	htree_dump_int_node(fs, ino, inode, (struct ext2_dx_entry *) (buf+8),
+			    cbuf, level);
+	free(cbuf);
+}
+
+
+
+void do_htree_dump(int argc, char *argv[])
+{
+	ext2_ino_t	ino;
+	struct ext2_inode inode;
+	int		retval;
+	int		i, c;
+	int		flags;
+	int		long_opt;
+	void		*buf = NULL;
+	struct 		ext2_dx_root_info  *root;
+	struct 		ext2_dx_entry *ent;
+	struct		ext2_dx_countlimit *limit;
+	errcode_t	errcode;
+
+	if (check_fs_open(argv[0]))
+		return;
+
+	pager = open_pager();
+
+	optind = 0;
+#ifdef HAVE_OPTRESET
+	optreset = 1;		/* Makes BSD getopt happy */
+#endif
+	while ((c = getopt (argc, argv, "l")) != EOF) {
+		switch (c) {
+		case 'l':
+			long_opt++;
+			break;
+		}
+	}
+
+	if (argc > optind+1) {
+		com_err(0, 0, "Usage: htree_dump [-l] file");
+		return;
+	}
+
+	if (argc == optind)
+		ino = cwd;
+	else
+		ino = string_to_inode(argv[optind]);
+	if (!ino)
+		return;
+
+	if (debugfs_read_inode(ino, &inode, argv[1]))
+		return;
+
+	if (!LINUX_S_ISDIR(inode.i_mode)) {
+		com_err(argv[0], 0, "Not a directory");
+		return;
+	}
+	
+	if ((inode.i_flags & EXT2_BTREE_FL) == 0) {
+		com_err(argv[0], 0, "Not a hash-indexed directory");
+		return;
+	}
+
+	buf = malloc(2*current_fs->blocksize);
+	if (!buf) {
+		com_err(argv[0], 0, "Couldn't allocate htree buffer");
+		return;
+	}
+
+	errcode = io_channel_read_blk(current_fs->io, inode.i_block[0], 
+				      1, buf);
+	if (errcode) {
+		com_err(argv[0], errcode, "Error reading root node");
+		goto errout;
+	}
+
+	root = (struct ext2_dx_root_info *) (buf + 24);
+
+	fprintf(pager, "Root node dump:\n");
+	fprintf(pager, "\t Reserved zero: %d\n", root->reserved_zero);
+	fprintf(pager, "\t Hash Version: %d\n", root->hash_version);
+	fprintf(pager, "\t Info length: %d\n", root->info_length);
+	fprintf(pager, "\t Indirect levels: %d\n", root->indirect_levels);
+	fprintf(pager, "\t Flags: %d\n", root->unused_flags);
+
+	ent = (struct ext2_dx_entry *) (buf + 24 + root->info_length);
+	limit = (struct ext2_dx_countlimit *) ent;
+
+	htree_dump_int_node(current_fs, ino, &inode, ent,
+			    buf + current_fs->blocksize,
+			    root->indirect_levels);
+
+errout:
+	if (buf)
+		free(buf);
+	close_pager(pager);
+}
+
+/*
+ * This function prints the hash of a given file.
+ */
+void do_dx_hash(int argc, char *argv[])
+{
+	if (argc != 2) {
+		com_err(argv[0], 0, "usage: dx_hash filename");
+		return;
+	}
+	printf("Hash of %s is 0x%0x\n", argv[1],
+	       dx_hash(argv[1], strlen(argv[1])));
+}
+
+/*
+ * Search for particular directory entry (useful for debugging very
+ * large hash tree directories that have lost some blocks from the
+ * btree index).
+ */
+struct process_block_struct {
+	char	*search_name;
+	char	*buf;
+	int	len;
+};
+
+static int search_dir_block(ext2_filsys fs, blk_t *blocknr,
+			    e2_blkcnt_t blockcnt, blk_t ref_blk, 
+			    int ref_offset, void *priv_data);
+
+void do_dirsearch(int argc, char *argv[])
+{
+	ext2_ino_t	inode;
+	int		retval;
+	int		c;
+	int		flags;
+	struct process_block_struct pb;
+	
+	if (check_fs_open(argv[0]))
+		return;
+
+	if (argc != 3) {
+		com_err(0, 0, "Usage: dirsearch dir filename");
+		return;
+	}
+
+	inode = string_to_inode(argv[1]);
+	if (!inode)
+		return;
+
+	pb.buf = malloc(current_fs->blocksize);
+	if (!pb.buf) {
+		com_err("dirsearch", 0, "Couldn't allocate buffer");
+		return;
+	}
+	pb.search_name = argv[2];
+	pb.len = strlen(pb.search_name);
+	
+	ext2fs_block_iterate2(current_fs, inode, 0, 0, search_dir_block, &pb);
+
+	free(pb.buf);
+}
+
+
+static int search_dir_block(ext2_filsys fs, blk_t *blocknr,
+			    e2_blkcnt_t blockcnt, blk_t ref_blk, 
+			    int ref_offset, void *priv_data)
+{
+	struct process_block_struct *p;
+	struct ext2_dir_entry *dirent;
+	errcode_t	       	errcode;
+	int			offset = 0;
+
+	if (blockcnt < 0)
+		return 0;
+
+	p = (struct process_block_struct *) priv_data;
+
+	errcode = io_channel_read_blk(current_fs->io, *blocknr, 1, p->buf);
+	if (errcode) {
+		com_err("search_dir_block", errcode,
+			"while reading block %lu", *blocknr);
+		return BLOCK_ABORT;
+	}
+
+	while (offset < fs->blocksize) {
+		dirent = (struct ext2_dir_entry *) (p->buf + offset);
+
+		if (dirent->inode &&
+		    p->len == (dirent->name_len & 0xFF) && 
+		    strncmp(p->search_name, dirent->name,
+			    p->len) == 0) {
+			printf("Entry found at logical block %lld, "
+			       "phys %d, offset %d\n", blockcnt,
+			       *blocknr, offset);
+			printf("offset %d\n", offset);
+			return BLOCK_ABORT;
+		}
+		offset += dirent->rec_len;
+	}
+	return 0;
+}
+
diff --git a/debugfs/util.c b/debugfs/util.c
index 183a5f6..fa13da4 100644
--- a/debugfs/util.c
+++ b/debugfs/util.c
@@ -22,14 +22,16 @@
 	const char *pager = getenv("PAGER");
 
 	signal(SIGPIPE, SIG_IGN);
-	if (!pager)
+	if (pager) {
+		if (strcmp(pager, "__none__") == 0) {
+			return stdout;
+		}
+	} else
 		pager = "more";
 
 	outfile = popen(pager, "w");
-	if (!outfile)
-		outfile = stdout;
 
-	return (outfile);
+	return (outfile ? outfile : stdout);
 }
 
 void close_pager(FILE *stream)
diff --git a/lib/ext2fs/ChangeLog b/lib/ext2fs/ChangeLog
index 4ed0472..4d0f646 100644
--- a/lib/ext2fs/ChangeLog
+++ b/lib/ext2fs/ChangeLog
@@ -1,3 +1,8 @@
+2002-02-25  Theodore Tso  <tytso@valinux.com>
+
+	* ext2_fs.h: Add structure definitions for the directory indexing
+		extension.
+
 2002-02-23  Theodore Tso  <tytso@valinux.com>
 
 	* unix_io.c (unix_open): Fix 2.4 resource limit workaround so that
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 38649df..1143965 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -147,6 +147,37 @@
 };
 
 /*
+ * Data structures used by the directory indexing feature
+ *
+ * Note: all of the multibyte integer fields are little endian.
+ */
+
+/*
+ * Note: dx_root_info is laid out so that if it should somehow get
+ * overlaid by a dirent the two low bits of the hash version will be
+ * zero.  Therefore, the hash version mod 4 should never be 0.
+ * Sincerely, the paranoia department.
+ */
+struct ext2_dx_root_info {
+	__u32 reserved_zero;
+	__u8 hash_version; /* 0 now, 1 at release */
+	__u8 info_length; /* 8 */
+	__u8 indirect_levels;
+	__u8 unused_flags;
+};
+
+struct ext2_dx_entry {
+	__u32 hash;
+	__u32 block;
+};
+
+struct ext2_dx_countlimit {
+	__u16 limit;
+	__u16 count;
+};
+
+
+/*
  * Macro-instructions used to manage group descriptors
  */
 #ifdef __KERNEL__