From 10ff68d42d06953c35459a0d949862e6aafa19f8 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Fri, 29 Aug 2008 21:21:19 -0400
Subject: [PATCH] tune2fs: Add support for setting the default hash algorithm
 for htree

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 misc/tune2fs.8.in | 10 +++++++++-
 misc/tune2fs.c    | 24 ++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/misc/tune2fs.8.in b/misc/tune2fs.8.in
index 9f8f23a..9abd898 100644
--- a/misc/tune2fs.8.in
+++ b/misc/tune2fs.8.in
@@ -164,7 +164,7 @@ metadata like bitmaps at
 time to avoid placing them on a single disk, which can hurt the performanace.
 It may also be used by block allocator.
 .TP
-.BI stripe-width= stripe-width
+.BI stripe_width= stripe-width
 Configure the filesystem for a RAID array with
 .I stripe-width
 filesystem blocks per stripe. This is typically be stride-size * N, where
@@ -172,6 +172,14 @@ N is the number of data disks in the RAID (e.g. RAID 5 N+1, RAID 6 N+2).
 This allows the block allocator to prevent read-modify-write of the
 parity in a RAID stripe if possible when the data is written.
 .TP
+.BI hash_alg= hash-alg
+Set the default hash algorithm used for filesystems with hashed b-tree
+directories.  Valid algorithms accepted are:
+.IR legacy ,
+.IR half_md4 ,
+and
+.IR tea .
+.TP
 .B test_fs
 Set a flag in the filesystem superblock indicating that it may be
 mounted using experimental kernel code, such as the ext4dev filesystem.
diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index ab35a71..5d4cfc0 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -855,7 +855,7 @@ void do_findfs(int argc, char **argv)
 static void parse_extended_opts(ext2_filsys fs, const char *opts)
 {
 	char	*buf, *token, *next, *p, *arg;
-	int	len;
+	int	len, hash_alg;
 	int	r_usage = 0;
 
 	len = strlen(opts);
@@ -915,6 +915,25 @@ static void parse_extended_opts(ext2_filsys fs, const char *opts)
 				continue;
 			}
 			stripe_width_set = 1;
+		} else if (strcmp(token, "hash_alg") == 0 ||
+			   strcmp(token, "hash-alg") == 0) {
+			if (!arg) {
+				r_usage++;
+				continue;
+			}
+			hash_alg = e2p_string2hash(arg);
+			if (hash_alg < 0) {
+				fprintf(stderr, 
+					_("Invalid hash algorithm: %s\n"),
+					arg);
+				r_usage++;
+				continue;
+			}
+			fs->super->s_def_hash_version = hash_alg;
+			printf(_("Setting default hash algorithm "
+				 "to %s (%d)\n"), 
+			       arg, hash_alg);
+			ext2fs_mark_super_dirty(fs);
 		} else
 			r_usage++;
 	}
@@ -925,7 +944,8 @@ static void parse_extended_opts(ext2_filsys fs, const char *opts)
 			"\tis set off by an equals ('=') sign.\n\n"
 			"Valid extended options are:\n"
 			"\tstride=<RAID per-disk chunk size in blocks>\n"
-			"\tstripe-width=<RAID stride*data disks in blocks>\n"
+			"\tstripe_width=<RAID stride*data disks in blocks>\n"
+			"\thash_alg=<hash algorithm>\n"
 			"\ttest_fs\n"
 			"\t^test_fs\n"));
 		free(buf);
-- 
1.8.3.1