chiark / gitweb /
volume_id: update ext detection
authorKay Sievers <kay.sievers@vrfy.org>
Sat, 9 Feb 2008 11:17:32 +0000 (12:17 +0100)
committerKay Sievers <kay.sievers@vrfy.org>
Sat, 9 Feb 2008 11:17:32 +0000 (12:17 +0100)
extras/volume_id/lib/ext.c

index 1997d42..ac21f12 100644 (file)
@@ -1,7 +1,10 @@
 /*
  * volume_id - reads filesystem label and uuid
  *
- * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2008 Theodore Ts'o <tytso@mit.edu>
+ *
+ * The probe logic is based on libblkid from e2fsutils.
  *
  *     This program is free software; you can redistribute it and/or modify it
  *     under the terms of the GNU General Public License as published by the
@@ -60,17 +63,63 @@ struct ext2_super_block {
        uint32_t        s_feature_ro_compat;
        uint8_t         s_uuid[16];
        uint8_t         s_volume_name[16];
+       uint8_t         s_last_mounted[64];
+       uint32_t        s_algorithm_usage_bitmap;
+       uint8_t         s_prealloc_blocks;
+       uint8_t         s_prealloc_dir_blocks;
+       uint16_t        s_reserved_gdt_blocks;
+       uint8_t         s_journal_uuid[16];
+       uint32_t        s_journal_inum;
+       uint32_t        s_journal_dev;
+       uint32_t        s_last_orphan;
+       uint32_t        s_hash_seed[4];
+       uint8_t         s_def_hash_version;
+       uint8_t         s_jnl_backup_type;
+       uint16_t        s_reserved_word_pad;
+       uint32_t        s_default_mount_opts;
+       uint32_t        s_first_meta_bg;
+       uint32_t        s_mkfs_time;
+       uint32_t        s_jnl_blocks[17];
+       uint32_t        s_blocks_count_hi;
+       uint32_t        s_r_blocks_count_hi;
+       uint32_t        s_free_blocks_hi;
+       uint16_t        s_min_extra_isize;
+       uint16_t        s_want_extra_isize;
+       uint32_t        s_flags;
 } PACKED;
 
 #define EXT_SUPER_MAGIC                                0xEF53
+#define EXT2_FLAGS_TEST_FILESYS                        0x0004
+#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER    0x0001
+#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE      0x0002
+#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR       0x0004
+#define EXT2_FEATURE_INCOMPAT_FILETYPE         0x0002
+#define EXT2_FEATURE_INCOMPAT_META_BG          0x0010
 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL                0x0004
 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV      0x0008
-#define EXT3_FEATURE_INCOMPAT_EXTENTS          0x0040
-#define EXT4_FEATURE_INCOMPAT_64BIT            0x0080
-#define EXT4_FEATURE_INCOMPAT_MMP              0x0100
+#define EXT3_FEATURE_INCOMPAT_RECOVER          0x0004
 
-#define EXT_SUPERBLOCK_OFFSET                  0x400
 
+#define EXT2_FEATURE_RO_COMPAT_SUPP    (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+                                        EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
+                                        EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
+#define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED     ~EXT2_FEATURE_RO_COMPAT_SUPP
+
+#define EXT2_FEATURE_INCOMPAT_SUPP     (EXT2_FEATURE_INCOMPAT_FILETYPE| \
+                                        EXT2_FEATURE_INCOMPAT_META_BG)
+#define EXT2_FEATURE_INCOMPAT_UNSUPPORTED      ~EXT2_FEATURE_INCOMPAT_SUPP
+
+#define EXT3_FEATURE_RO_COMPAT_SUPP    (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+                                        EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
+                                        EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
+#define EXT3_FEATURE_RO_COMPAT_UNSUPPORTED     ~EXT3_FEATURE_RO_COMPAT_SUPP
+
+#define EXT3_FEATURE_INCOMPAT_SUPP     (EXT2_FEATURE_INCOMPAT_FILETYPE| \
+                                        EXT3_FEATURE_INCOMPAT_RECOVER| \
+                                        EXT2_FEATURE_INCOMPAT_META_BG)
+#define EXT3_FEATURE_INCOMPAT_UNSUPPORTED      ~EXT3_FEATURE_INCOMPAT_SUPP
+
+#define EXT_SUPERBLOCK_OFFSET                  0x400
 #define EXT3_MIN_BLOCK_SIZE                    0x400
 #define EXT3_MAX_BLOCK_SIZE                    0x1000
 
@@ -79,7 +128,9 @@ int volume_id_probe_ext(struct volume_id *id, uint64_t off, uint64_t size)
        struct ext2_super_block *es;
        size_t bsize;
        uint32_t feature_compat;
+       uint32_t feature_ro_compat;
        uint32_t feature_incompat;
+       uint32_t flags;
 
        info("probing at offset 0x%llx", (unsigned long long) off);
 
@@ -97,38 +148,53 @@ int volume_id_probe_ext(struct volume_id *id, uint64_t off, uint64_t size)
                return -1;
        }
 
-       volume_id_set_label_raw(id, es->s_volume_name, 16);
-       volume_id_set_label_string(id, es->s_volume_name, 16);
-       volume_id_set_uuid(id, es->s_uuid, 0, UUID_DCE);
-       snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u",
-                le32_to_cpu(es->s_rev_level), le16_to_cpu(es->s_minor_rev_level));
-
        feature_compat = le32_to_cpu(es->s_feature_compat);
+       feature_ro_compat = le32_to_cpu(es->s_feature_ro_compat);
        feature_incompat = le32_to_cpu(es->s_feature_incompat);
+       flags = le32_to_cpu(es->s_flags);
 
-       /* check for external journal device */
+       /* external journal device is jbd */
        if ((feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) != 0) {
                volume_id_set_usage(id, VOLUME_ID_OTHER);
                id->type = "jbd";
-               goto out;
-       }
-
-       volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
-
-       if ((feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) != 0 ||
-           (feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) != 0 ||
-           (feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) != 0) {
-               id->type = "ext4";
-               goto out;
+               goto found;
        }
 
+       /* has journal */
        if ((feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) != 0) {
+               /* "use on development code" is ext4dev */
+               if ((flags & EXT2_FLAGS_TEST_FILESYS) != 0) {
+                       id->type = "ext4dev";
+                       goto found;
+               }
+
+               /* incompatible ext3 features is ext4 */
+               if ((feature_ro_compat & EXT3_FEATURE_RO_COMPAT_UNSUPPORTED) != 0 ||
+                   (feature_incompat & EXT3_FEATURE_INCOMPAT_UNSUPPORTED) != 0) {
+                       id->type = "ext4";
+                       goto found;
+               }
+
                id->type = "ext3";
-               goto out;
+               goto found;
+       } else {
+               /* no incompatible ext2 feature is ext2 */
+               if ((feature_ro_compat & EXT2_FEATURE_RO_COMPAT_UNSUPPORTED) == 0 &&
+                   (feature_incompat & EXT2_FEATURE_INCOMPAT_UNSUPPORTED) == 0) {
+                       id->type = "ext2";
+                       goto found;
+               }
        }
 
-       id->type = "ext2";
+       return -1;
+
+found:
+       volume_id_set_label_raw(id, es->s_volume_name, 16);
+       volume_id_set_label_string(id, es->s_volume_name, 16);
+       volume_id_set_uuid(id, es->s_uuid, 0, UUID_DCE);
+       snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u",
+                le32_to_cpu(es->s_rev_level), le16_to_cpu(es->s_minor_rev_level));
 
-out:
+       volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
        return 0;
 }