libblkid: add erofs filesystem support

Enhanced Read-Only File System (EROFS) has been included in Linux kernel, many Linux distributions, buildroot and Android AOSP for a while. Plus, nowadays, it's known that EROFS has been commercially used by several Android vendors for their system partitions. This patch adds support for detecting EROFS filesystem to libblkid. Since util-linux/util-linux@cd129b7 introduced blkid_probe_set_block_size function to report filesystem block size, TWRP is using blkid 2.25.0, which means blkid_probe_set_block_size wasn't supported and required, so remove the blkszbits judgement and blkid_probe_set_block_size for fixing building. Test: Add erofs mount point to twrp.flags, build and boot OP4A7A:/ # logcat | grep erofs I (6)[571:recovery]erofs: (device dm-0): mounted with opts: , root inode @ nid 58. I (6)[571:recovery]erofs: (device dm-9): mounted with opts: , root inode @ nid 43. I (6)[571:recovery]erofs: (device dm-1): mounted with opts: , root inode @ nid 52. I (6)[571:recovery]erofs: (device dm-10): mounted with opts: , root inode @ nid 45. I (6)[571:recovery]erofs: (device dm-8): mounted with opts: , root inode @ nid 42. I (0)[571:recovery]erofs: (device dm-12): mounted with opts: , root inode @ nid 38. I (3)[571:recovery]erofs: (device dm-0): mounted with opts: , root inode @ nid 58. I (3)[571:recovery]erofs: (device dm-1): mounted with opts: , root inode @ nid 52. I (3)[571:recovery]erofs: (device dm-0): mounted with opts: , root inode @ nid 58. I (3)[571:recovery]erofs: (device dm-0): mounted with opts: , root inode @ nid 58. I (3)[571:recovery]erofs: (device dm-9): mounted with opts: , root inode @ nid 43. I (2)[571:recovery]erofs: (device dm-1): mounted with opts: , root inode @ nid 52. I (2)[571:recovery]erofs: (device dm-10): mounted with opts: , root inode @ nid 45. I (2)[571:recovery]erofs: (device dm-8): mounted with opts: , root inode @ nid 42. I (2)[571:recovery]erofs: (device dm-12): mounted with opts: , root inode @ nid 38. I (6)[571:recovery]erofs: (device dm-0): mounted with opts: , root inode @ nid 58. I (6)[571:recovery]erofs: (device dm-0): mounted with opts: , root inode @ nid 58. OP4A7A:/ # cat /tmp/recovery.log | grep erofs Current_File_System: erofs Fstab_File_System: erofs Current_File_System: erofs Fstab_File_System: erofs Fstab_File_System: erofs Current_File_System: erofs Fstab_File_System: erofs Current_File_System: erofs Fstab_File_System: erofs Current_File_System: erofs Fstab_File_System: erofs Current_File_System: erofs Fstab_File_System: erofs Now TWRP can recognize the EROFS filesystem perfectly after setting fs in twrp.flags Signed-off-by: Gao Xiang <[email protected]> [@pomelohan: Adapt for TWRP's libblkid version and add erofs.c to build] Co-authored-by: GarfieldHan <[email protected]> Signed-off-by: GarfieldHan <[email protected]> Change-Id: I00263757b5b6ed881165e65795ef849d86763165
SHRP · Dec 27, 2021 · bdd15ee · bdd15ee
1 parent 8b06436
commit bdd15ee
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diff --git a/libblkid/Android.mk b/libblkid/Android.mk
@@ -146,6 +146,7 @@ LOCAL_SRC_FILES = 	src/cache.c \
 			src/superblocks/drbdproxy_datalog.c \
 			src/superblocks/exfat.c \
 			src/superblocks/ext.c \
+			src/superblocks/erofs.c \
 			src/superblocks/f2fs.c \
 			src/superblocks/gfs.c \
 			src/superblocks/hfs.c \

diff --git a/libblkid/src/superblocks/erofs.c b/libblkid/src/superblocks/erofs.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2020 Gao Xiang
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License
+ */
+#include <stddef.h>
+#include <string.h>
+
+#include "superblocks.h"
+
+#define EROFS_SUPER_OFFSET      1024
+#define EROFS_SB_KBOFF		(EROFS_SUPER_OFFSET >> 10)
+
+#define EROFS_SUPER_MAGIC_V1	"\xe2\xe1\xf5\xe0"
+#define EROFS_MAGIC_OFF		0
+
+/* All in little-endian */
+struct erofs_super_block {
+	uint32_t	magic;
+	uint32_t	checksum;
+	uint32_t	feature_compat;
+	uint8_t		blkszbits;
+	uint8_t		reserved;
+
+	uint16_t	root_nid;
+	uint64_t	inos;
+
+	uint64_t	build_time;
+	uint32_t	build_time_nsec;
+	uint32_t	blocks;
+	uint32_t	meta_blkaddr;
+	uint32_t	xattr_blkaddr;
+	uint8_t		uuid[16];
+	uint8_t		volume_name[16];
+	uint32_t	feature_incompat;
+	uint8_t		reserved2[44];
+};
+
+static int probe_erofs(blkid_probe pr, const struct blkid_idmag *mag)
+{
+	struct erofs_super_block *sb;
+
+	sb = blkid_probe_get_sb(pr, mag, struct erofs_super_block);
+	if (!sb)
+		return errno ? -errno : BLKID_PROBE_NONE;
+
+	if (sb->volume_name[0])
+		blkid_probe_set_label(pr, (unsigned char *)sb->volume_name,
+				      sizeof(sb->volume_name));
+
+	blkid_probe_set_uuid(pr, sb->uuid);
+
+	return BLKID_PROBE_OK;
+}
+
+const struct blkid_idinfo erofs_idinfo =
+{
+	.name           = "erofs",
+	.usage          = BLKID_USAGE_FILESYSTEM,
+	.probefunc      = probe_erofs,
+	.magics         =
+        {
+		{
+			.magic = EROFS_SUPER_MAGIC_V1,
+			.len = 4,
+			.kboff = EROFS_SB_KBOFF,
+			.sboff = EROFS_MAGIC_OFF,
+		}, { NULL }
+	}
+};
diff --git a/libblkid/src/superblocks/superblocks.c b/libblkid/src/superblocks/superblocks.c
@@ -155,7 +155,8 @@ static const struct blkid_idinfo *idinfos[] =
 	&befs_idinfo,
 	&nilfs2_idinfo,
 	&exfat_idinfo,
-	&f2fs_idinfo
+	&f2fs_idinfo,
+	&erofs_idinfo
 };
 
 /*

diff --git a/libblkid/src/superblocks/superblocks.h b/libblkid/src/superblocks/superblocks.h
@@ -74,6 +74,7 @@ extern const struct blkid_idinfo nilfs2_idinfo;
 extern const struct blkid_idinfo exfat_idinfo;
 extern const struct blkid_idinfo f2fs_idinfo;
 extern const struct blkid_idinfo bcache_idinfo;
+extern const struct blkid_idinfo erofs_idinfo;
 
 /*
  * superblock functions