add debugfs command to print known features

Print out the currently supported features of e2fsprogs/libext2fs
via a new "debugfs supported_features" command.  This helps scripts
to know whether it is possible to try and enable specific features
in the filesystem.

Signed-off-by: Kalpak Shah <kalpak.shah@sun.com>
Signed-off-by: Andreas Dilger <adilger@sun.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

5 files changed, 210 insertions, 2 deletions

diff --git a/debugfs/debug_cmds.ct b/debugfs/debug_cmds.ct
index a4a5a4c1..59314b81 100644
--- a/debugfs/debug_cmds.ct
+++ b/debugfs/debug_cmds.ct
@@ -154,5 +154,8 @@ request	do_dump_unused, "Dump unused blocks",
 request do_set_current_time, "Set current time to use when setting filesystme fields",
 	set_current_time;
 
+request do_supported_features, "Print features supported by this version of e2fsprogs",
+	supported_features;
+
 end;
 
diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
index 935df812..620a513c 100644
--- a/debugfs/debugfs.c
+++ b/debugfs/debugfs.c
@@ -36,6 +36,7 @@ extern char *optarg;
 #include <ext2fs/ext2_ext_attr.h>
 
 #include "../version.h"
+#include "jfs_user.h"
 
 extern ss_request_table debug_cmds;
 ss_request_table *extra_cmds;
@@ -1806,6 +1807,71 @@ void do_set_current_time(int argc, char *argv[])
 	}
 }
 
+static int find_supp_feature(__u32 *supp, int feature_type, char *name)
+{
+	int compat, bit, ret;
+	unsigned int feature_mask;
+
+	if (name) {
+		if (feature_type == E2P_FS_FEATURE)
+			ret = e2p_string2feature(name, &compat, &feature_mask);
+		else
+			ret = e2p_jrnl_string2feature(name, &compat,
+						      &feature_mask);
+		if (ret)
+			return ret;
+
+		if (!(supp[compat] & feature_mask))
+			return 1;
+	} else {
+	        for (compat = 0; compat < 3; compat++) {
+		        for (bit = 0, feature_mask = 1; bit < 32;
+			     bit++, feature_mask <<= 1) {
+			        if (supp[compat] & feature_mask) {
+					if (feature_type == E2P_FS_FEATURE)
+						fprintf(stdout, " %s",
+						e2p_feature2string(compat,
+						feature_mask));
+					else
+						fprintf(stdout, " %s",
+						e2p_jrnl_feature2string(compat,
+						feature_mask));
+				}
+	        	}
+		}
+	        fprintf(stdout, "\n");
+	}
+
+	return 0;
+}
+
+void do_supported_features(int argc, char *argv[])
+{
+        int	i, j, ret;
+	__u32	supp[3] = { EXT2_LIB_FEATURE_COMPAT_SUPP,
+			    EXT2_LIB_FEATURE_INCOMPAT_SUPP,
+			    EXT2_LIB_FEATURE_RO_COMPAT_SUPP };
+	__u32	jrnl_supp[3] = { JFS_KNOWN_COMPAT_FEATURES,
+				 JFS_KNOWN_INCOMPAT_FEATURES,
+				 JFS_KNOWN_ROCOMPAT_FEATURES };
+
+	if (argc > 1) {
+		ret = find_supp_feature(supp, E2P_FS_FEATURE, argv[1]);
+		if (ret) {
+			ret = find_supp_feature(jrnl_supp, E2P_JOURNAL_FEATURE,
+						argv[1]);
+		}
+		if (ret)
+			com_err(argv[0], 0, "Unknown feature: %s\n", argv[1]);
+		else
+			fprintf(stdout, "Supported feature: %s\n", argv[1]);
+	} else {
+		fprintf(stdout, "Supported features:");
+		ret = find_supp_feature(supp, E2P_FS_FEATURE, NULL);
+		ret = find_supp_feature(jrnl_supp, E2P_JOURNAL_FEATURE, NULL);
+	}
+}
+
 static int source_file(const char *cmd_file, int sci_idx)
 {
 	FILE		*f;
diff --git a/lib/e2p/Makefile.in b/lib/e2p/Makefile.in
index 65574802..2c56ab5f 100644
--- a/lib/e2p/Makefile.in
+++ b/lib/e2p/Makefile.in
@@ -69,8 +69,14 @@ tst_ostype: $(srcdir)/ostype.c
 	@$(CC) -DTEST_PROGRAM -I$(top_srcdir)/lib -o tst_ostype \
 		$(srcdir)/ostype.c $(ALL_CFLAGS)
 
-check::	tst_ostype
+tst_feature: $(srcdir)/feature.c
+	@echo "	LD $@"
+	@$(CC) -DTEST_PROGRAM -I$(top_srcdir)/lib -o tst_feature \
+		$(srcdir)/feature.c $(ALL_CFLAGS)
+
+check::	tst_ostype tst_feature
 	./tst_ostype
+	./tst_feature
 
 installdirs::
 	@echo "	MKINSTALLDIRS $(libdir) $(includedir)/e2p"
@@ -96,7 +102,7 @@ uninstall::
 
 clean::
 	$(RM) -f \#* *.s *.o *.a *~ *.bak core profiled/* checker/*
-	$(RM) -f ../libe2p.a ../libe2p_p.a tst_ostype
+	$(RM) -f ../libe2p.a ../libe2p_p.a tst_ostype tst_feature
 
 mostlyclean:: clean
 distclean:: clean
diff --git a/lib/e2p/e2p.h b/lib/e2p/e2p.h
index 06e2120d..ad607f68 100644
--- a/lib/e2p/e2p.h
+++ b/lib/e2p/e2p.h
@@ -11,6 +11,9 @@
 
 #define E2P_FEATURE_NEGATE_FLAG	0x80
 
+#define E2P_FS_FEATURE		0
+#define E2P_JOURNAL_FEATURE	1
+
 /* `options' for print_flags() */
 
 #define PFOPT_LONG  1 /* Must be 1 for compatibility with `int long_format'. */
diff --git a/lib/e2p/feature.c b/lib/e2p/feature.c
index 12cb8a32..e3a72047 100644
--- a/lib/e2p/feature.c
+++ b/lib/e2p/feature.c
@@ -15,6 +15,8 @@
 #include <errno.h>
 
 #include "e2p.h"
+#include <ext2fs/ext2fs.h>
+#include <ext2fs/jfs_user.h>
 
 struct feature {
 	int		compat;
@@ -74,6 +76,17 @@ static struct feature feature_list[] = {
 	{	0, 0, 0 },
 };
 
+static struct feature jrnl_feature_list[] = {
+       {       E2P_FEATURE_COMPAT, JFS_FEATURE_COMPAT_CHECKSUM,
+                       "journal_checksum" },
+
+       {       E2P_FEATURE_INCOMPAT, JFS_FEATURE_INCOMPAT_REVOKE,
+                       "journal_incompat_revoke" },
+       {       E2P_FEATURE_INCOMPAT, JFS_FEATURE_INCOMPAT_ASYNC_COMMIT,
+                       "journal_async_commit" },
+       {       0, 0, 0 },
+};
+
 const char *e2p_feature2string(int compat, unsigned int mask)
 {
 	struct feature  *f;
@@ -148,6 +161,79 @@ int e2p_string2feature(char *string, int *compat_type, unsigned int *mask)
 	return 0;
 }
 
+const char *e2p_jrnl_feature2string(int compat, unsigned int mask)
+{
+	struct feature  *f;
+	static char buf[20];
+	char	fchar;
+	int	fnum;
+
+	for (f = jrnl_feature_list; f->string; f++) {
+		if ((compat == f->compat) &&
+		    (mask == f->mask))
+			return f->string;
+	}
+	switch (compat) {
+	case  E2P_FEATURE_COMPAT:
+		fchar = 'C';
+		break;
+	case E2P_FEATURE_INCOMPAT:
+		fchar = 'I';
+		break;
+	case E2P_FEATURE_RO_INCOMPAT:
+		fchar = 'R';
+		break;
+	default:
+		fchar = '?';
+		break;
+	}
+	for (fnum = 0; mask >>= 1; fnum++);
+	sprintf(buf, "FEATURE_%c%d", fchar, fnum);
+	return buf;
+}
+
+int e2p_jrnl_string2feature(char *string, int *compat_type, unsigned int *mask)
+{
+	struct feature  *f;
+	char		*eptr;
+	int		num;
+
+	for (f = jrnl_feature_list; f->string; f++) {
+		if (!strcasecmp(string, f->string)) {
+			*compat_type = f->compat;
+			*mask = f->mask;
+			return 0;
+		}
+	}
+	if (strncasecmp(string, "FEATURE_", 8))
+		return 1;
+
+	switch (string[8]) {
+	case 'c':
+	case 'C':
+		*compat_type = E2P_FEATURE_COMPAT;
+		break;
+	case 'i':
+	case 'I':
+		*compat_type = E2P_FEATURE_INCOMPAT;
+		break;
+	case 'r':
+	case 'R':
+		*compat_type = E2P_FEATURE_RO_INCOMPAT;
+		break;
+	default:
+		return 1;
+	}
+	if (string[9] == 0)
+		return 1;
+	num = strtol(string+9, &eptr, 10);
+	if (num > 32 || num < 0)
+		return 1;
+	if (*eptr)
+		return 1;
+	*mask = 1 << num;
+	return 0;
+}
 static char *skip_over_blanks(char *cp)
 {
 	while (*cp && isspace(*cp))
@@ -252,3 +338,47 @@ int e2p_edit_feature(const char *str, __u32 *compat_array, __u32 *ok_array)
 {
 	return e2p_edit_feature2(str, compat_array, ok_array, 0, 0, 0);
 }
+
+#ifdef TEST_PROGRAM
+int main(int argc, char **argv)
+{
+	int compat, compat2, i;
+	unsigned int mask, mask2;
+	const char *str;
+	struct feature *f;
+
+	for (i = 0; i < 2; i++) {
+		if (i == 0) {
+			f = feature_list;
+			printf("Feature list:\n");
+		} else {
+			printf("\nJournal feature list:\n");
+			f = jrnl_feature_list;
+		}
+		for (; f->string; f++) {
+			if (i == 0) {
+				e2p_string2feature((char *)f->string, &compat,
+						   &mask);
+				str = e2p_feature2string(compat, mask);
+			} else {
+				e2p_jrnl_string2feature((char *)f->string,
+							&compat, &mask);
+				str = e2p_jrnl_feature2string(compat, mask);
+			}
+
+			printf("\tCompat = %d, Mask = %u, %s\n",
+			       compat, mask, f->string);
+			if (strcmp(f->string, str)) {
+				if (e2p_string2feature((char *) str, &compat2,
+						       &mask2) ||
+				    (compat2 != compat) ||
+				    (mask2 != mask)) {
+					fprintf(stderr, "Failure!\n");
+					exit(1);
+				}
+			}
+		}
+	}
+	exit(0);
+}
+#endif