ANDROID: tune2fs: Allow setting the casefold feature

This allows tune2fs to enable casefolding on an existing filesystem.
At the moment, casefolding is incompatible with encryption.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 159836819
Test: Create fs without casefold and enable it via tune2fs
Change-Id: Ic9ed63180ef28c36e083cee85ade432e4bfcc654

2 files changed, 122 insertions, 7 deletions

diff --git a/misc/tune2fs.8.in b/misc/tune2fs.8.in
index 74eebb6a..8b3604f4 100644
--- a/misc/tune2fs.8.in
+++ b/misc/tune2fs.8.in
@@ -218,6 +218,33 @@ directories.  Valid algorithms accepted are:
 and
 .IR tea .
 .TP
+.BI encoding= encoding-name
+Enable the
+.I casefold
+feature in the super block and set
+.I encoding-name
+as the encoding to be used.  If
+.I encoding-name
+is not specified, utf8 is used. The encoding cannot be altered if casefold
+was previously enabled.
+.TP
+.BI encoding_flags= encoding-flags
+Override the flags for filename encoding.  This option may only be specified
+when
+.I encoding-name
+is also specified and when the file system doesn't already have the
+.I casefold
+feature enabled.  Currently the only recognized flag is
+.I strict
+which means that invalid filenames are rejected by the file system.  By default,
+.I strict
+is not enabled.
+Flags may be prefixed with "no" to explicitly leave them disabled, e.g.
+.I nostrict
+to explicitly leave the
+.I strict
+flag disabled.
+.TP
 .BI mount_opts= mount_option_string
 Set a set of default mount options which will be used when the file
 system is mounted.  Unlike the bitmask-based default mount options which
@@ -536,6 +563,11 @@ The following filesystem features can be set or cleared using
 .B 64bit
 Enable the file system to be larger than 2^32 blocks.
 .TP
+.B casefold
+Enable support for file system level casefolding.
+.B Tune2fs
+currently only supports setting this filesystem feature.
+.TP
 .B dir_index
 Use hashed b-trees to speed up lookups for large directories.
 .TP
diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index c31c9a7c..d9aba852 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -101,6 +101,7 @@ static int rewrite_checksums;
 static int feature_64bit;
 static int fsck_requested;
 static char *undo_file;
+static int enabling_casefold;
 
 int journal_size, journal_flags;
 char *journal_device;
@@ -160,7 +161,8 @@ static __u32 ok_features[3] = {
 		EXT4_FEATURE_INCOMPAT_64BIT |
 		EXT4_FEATURE_INCOMPAT_ENCRYPT |
 		EXT4_FEATURE_INCOMPAT_CSUM_SEED |
-		EXT4_FEATURE_INCOMPAT_LARGEDIR,
+		EXT4_FEATURE_INCOMPAT_LARGEDIR |
+		EXT4_FEATURE_INCOMPAT_CASEFOLD,
 	/* R/O compat */
 	EXT2_FEATURE_RO_COMPAT_LARGE_FILE |
 		EXT4_FEATURE_RO_COMPAT_HUGE_FILE|
@@ -1415,6 +1417,23 @@ mmp_error:
 			EXT4_ENCRYPTION_MODE_AES_256_CTS;
 	}
 
+	if (FEATURE_ON(E2P_FEATURE_INCOMPAT, EXT4_FEATURE_INCOMPAT_CASEFOLD)) {
+		if (ext2fs_has_feature_encrypt(sb)) {
+			fputs(_("Cannot enable casefold feature on filesystems "
+				"with the encrypt feature enabled.\n"),
+			      stderr);
+			return 1;
+		}
+		if (mount_flags & EXT2_MF_MOUNTED) {
+			fputs(_("The casefold feature may only be enabled when "
+				"the filesystem is unmounted.\n"), stderr);
+			return 1;
+		}
+		fs->super->s_encoding = EXT4_ENC_UTF8_12_1;
+		fs->super->s_encoding_flags = e2p_get_encoding_flags(EXT4_ENC_UTF8_12_1);
+		enabling_casefold = 1;
+	}
+
 	if (FEATURE_ON(E2P_FEATURE_INCOMPAT,
 		EXT4_FEATURE_INCOMPAT_CSUM_SEED)) {
 		if (!ext2fs_has_feature_metadata_csum(sb)) {
@@ -2018,9 +2037,12 @@ void do_findfs(int argc, char **argv)
 
 static int parse_extended_opts(ext2_filsys fs, const char *opts)
 {
+	struct ext2_super_block *sb = fs->super;
 	char	*buf, *token, *next, *p, *arg;
 	int	len, hash_alg;
 	int	r_usage = 0;
+	int	encoding = 0;
+	char	*encoding_flags = NULL;
 
 	len = strlen(opts);
 	buf = malloc(len+1);
@@ -2073,18 +2095,18 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts)
 				  "Setting multiple mount protection update "
 				  "interval to %lu seconds\n", intv),
 			       intv);
-			fs->super->s_mmp_update_interval = intv;
+			sb->s_mmp_update_interval = intv;
 			ext2fs_mark_super_dirty(fs);
 		} else if (!strcmp(token, "force_fsck")) {
-			fs->super->s_state |= EXT2_ERROR_FS;
+			sb->s_state |= EXT2_ERROR_FS;
 			printf(_("Setting filesystem error flag to force fsck.\n"));
 			ext2fs_mark_super_dirty(fs);
 		} else if (!strcmp(token, "test_fs")) {
-			fs->super->s_flags |= EXT2_FLAGS_TEST_FILESYS;
+			sb->s_flags |= EXT2_FLAGS_TEST_FILESYS;
 			printf("Setting test filesystem flag\n");
 			ext2fs_mark_super_dirty(fs);
 		} else if (!strcmp(token, "^test_fs")) {
-			fs->super->s_flags &= ~EXT2_FLAGS_TEST_FILESYS;
+			sb->s_flags &= ~EXT2_FLAGS_TEST_FILESYS;
 			printf("Clearing test filesystem flag\n");
 			ext2fs_mark_super_dirty(fs);
 		} else if (strcmp(token, "stride") == 0) {
@@ -2130,7 +2152,7 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts)
 				r_usage++;
 				continue;
 			}
-			fs->super->s_def_hash_version = hash_alg;
+			sb->s_def_hash_version = hash_alg;
 			printf(_("Setting default hash algorithm "
 				 "to %s (%d)\n"),
 			       arg, hash_alg);
@@ -2146,9 +2168,68 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts)
 				continue;
 			}
 			ext_mount_opts = strdup(arg);
+		} else if (!strcmp(token, "encoding")) {
+			if (!arg) {
+				r_usage++;
+				continue;
+			}
+			if (ext2fs_has_feature_encrypt(sb)) {
+				fprintf(stderr, _("error: Cannot enable casefolding if encryption is set\n"));
+				r_usage++;
+				continue;
+			}
+			if (mount_flags & EXT2_MF_MOUNTED) {
+				fputs(_("The casefold feature may only be enabled when "
+					"the filesystem is unmounted.\n"), stderr);
+				r_usage++;
+				continue;
+			}
+			if (ext2fs_has_feature_casefold(sb) && !enabling_casefold) {
+				fprintf(stderr, _("Cannot alter existing encoding\n"));
+				r_usage++;
+				continue;
+			}
+			encoding = e2p_str2encoding(arg);
+			if (encoding < 0) {
+				fprintf(stderr, _("Invalid encoding: %s\n"), arg);
+				r_usage++;
+				continue;
+			}
+			enabling_casefold = 1;
+			sb->s_encoding = encoding;
+			printf(_("Setting encoding to '%s'\n"), arg);
+			sb->s_encoding_flags =
+				e2p_get_encoding_flags(sb->s_encoding);
+		} else if (!strcmp(token, "encoding_flags")) {
+			if (!arg) {
+				r_usage++;
+				continue;
+			}
+			encoding_flags = arg;
 		} else
 			r_usage++;
 	}
+
+	if (encoding > 0 && !r_usage) {
+		sb->s_encoding_flags =
+			e2p_get_encoding_flags(sb->s_encoding);
+
+		if (encoding_flags &&
+		    e2p_str2encoding_flags(sb->s_encoding, encoding_flags,
+					   &sb->s_encoding_flags)) {
+			fprintf(stderr, _("error: Invalid encoding flag: %s\n"),
+					encoding_flags);
+			r_usage++;
+		} else if (encoding_flags)
+			printf(_("Setting encoding_flags to '%s'\n"),
+				 encoding_flags);
+		ext2fs_set_feature_casefold(sb);
+		ext2fs_mark_super_dirty(fs);
+	} else if (encoding_flags && !r_usage) {
+		fprintf(stderr, _("error: An encoding must be explicitly "
+				  "specified when passing encoding-flags\n"));
+		r_usage++;
+	}
 	if (r_usage) {
 		fprintf(stderr, "%s", _("\nBad options specified.\n\n"
 			"Extended options are separated by commas, "
@@ -2163,7 +2244,9 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts)
 			"\tstripe_width=<RAID stride*data disks in blocks>\n"
 			"\tforce_fsck\n"
 			"\ttest_fs\n"
-			"\t^test_fs\n"));
+			"\t^test_fs\n"
+			"\tencoding=<encoding>\n"
+			"\tencoding_flags=<flags>\n"));
 		free(buf);
 		return 1;
 	}