mke2fs: print extra information about existing ext2/3/4 file systems

The basic idea is to provide a bit more context in this situation:

% ./misc/mke2fs -t ext4 /dev/sdc3
mke2fs 1.42.9 (4-Feb-2014)
/dev/sdc3 contains a ext4 file system
Proceed anyway? (y,n)

... by adding this bit of context:

% ./misc/mke2fs -t ext4 /dev/sdc3
mke2fs 1.42.9 (4-Feb-2014)
/dev/sdc3 contains a ext4 file system
	last mounted on /SOX-backups on Mon May  5 08:59:53 2014
Proceed anyway? (y,n)

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/misc/util.c b/misc/util.c
index 15b4ce5..051183e 100644 (file)
--- a/misc/util.c
+++ b/misc/util.c
@@ -105,6 +105,42 @@ void proceed_question(int delay)
        signal(SIGALRM, SIG_IGN);
 }
 
+static void print_ext2_info(const char *device)
+
+{
+       struct ext2_super_block *sb;
+       ext2_filsys             fs;
+       errcode_t               retval;
+       time_t                  tm;
+       char                    buf[80];
+
+       retval = ext2fs_open2(device, 0, EXT2_FLAG_64BITS, 0, 0,
+                             unix_io_manager, &fs);
+       if (retval)
+               return;
+       sb = fs->super;
+
+       if (sb->s_mtime) {
+               tm = sb->s_mtime;
+               if (sb->s_last_mounted[0]) {
+                       memset(buf, 0, sizeof(buf));
+                       strncpy(buf, sb->s_last_mounted,
+                               sizeof(sb->s_last_mounted));
+                       printf(_("\tlast mounted on %s on %s"), buf,
+                              ctime(&tm));
+               } else
+                       printf(_("\tlast mounted on %s"), ctime(&tm));
+       } else if (sb->s_mkfs_time) {
+               tm = sb->s_mkfs_time;
+               printf(_("\tcreated on %s"), ctime(&tm));
+       } else if (sb->s_wtime) {
+               tm = sb->s_wtime;
+               printf(_("\tlast modified on %s"), ctime(&tm));
+       }
+       ext2fs_close(fs);
+}
+
+
 /*
  * return 1 if the device looks plausible, creating the file if necessary
  */
@@ -168,6 +204,8 @@ int check_plausibility(const char *device, int flags, int *ret_is_dev)
                else
                        printf(_("%s contains a %s file system\n"), device,
                               fs_type);
+               if (strncmp(fs_type, "ext", 3) == 0)
+                       print_ext2_info(device);
                free(fs_type);
                free(fs_label);
                return 0;