[U-Boot] [PATCH 1/1] fs: ext4: do not write on filesystem with metadata_csum feature

[Sébastien Szymanski]

U-Boot doesn't support metadata_csum feature. Writing to filesystem with
metadata_csum feature makes the filesystem corrupted and unbootable by
Linux:

[    2.527495] EXT4-fs (mmcblk0p2): ext4_check_descriptors: Checksum for group 0 failed (52188!=0)
[    2.537421] EXT4-fs (mmcblk0p2): ext4_check_descriptors: Checksum for group 1 failed (5262!=0)
...
[    2.653308] EXT4-fs (mmcblk0p2): ext4_check_descriptors: Checksum for group 14 failed (42611!=0)
[    2.662179] EXT4-fs (mmcblk0p2): ext4_check_descriptors: Checksum for group 15 failed (21527!=0)
[    2.687920] JBD2: journal checksum error
[    2.691982] EXT4-fs (mmcblk0p2): error loading journal
[    2.698292] VFS: Cannot open root device "mmcblk0p2" or unknown-block(179,2): error -74

Don't write to filesystem with meatadata_csum feature to not corrupt the
filesystem.

Signed-off-by: Sébastien Szymanski <sebastien.szymanski at armadeus.com>
---
 fs/ext4/ext4_write.c | 6 ++++++
 include/ext4fs.h     | 1 +
 2 files changed, 7 insertions(+)

diff --git a/fs/ext4/ext4_write.c b/fs/ext4/ext4_write.c
index a7f543f7df..4eb77c327e 100644
--- a/fs/ext4/ext4_write.c
+++ b/fs/ext4/ext4_write.c
@@ -864,6 +864,12 @@ int ext4fs_write(const char *fname, unsigned char *buffer,
 		printf("error in File System init\n");
 		return -1;
 	}
+
+	if (le32_to_cpu(fs->sb->feature_ro_compat) & EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) {
+		printf("Unsupported feature metadata_csum found, not writing.\n");
+		return -1;
+	}
+
 	inodes_per_block = fs->blksz / fs->inodesz;
 	parent_inodeno = ext4fs_get_parent_inode_num(fname, filename, F_FILE);
 	if (parent_inodeno == -1)
diff --git a/include/ext4fs.h b/include/ext4fs.h
index bb55639107..2421011341 100644
--- a/include/ext4fs.h
+++ b/include/ext4fs.h
@@ -32,6 +32,7 @@
 #define EXT4_EXTENTS_FL		0x00080000 /* Inode uses extents */
 #define EXT4_EXT_MAGIC			0xf30a
 #define EXT4_FEATURE_RO_COMPAT_GDT_CSUM	0x0010
+#define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM 0x0400
 #define EXT4_FEATURE_INCOMPAT_EXTENTS	0x0040
 #define EXT4_FEATURE_INCOMPAT_64BIT	0x0080
 #define EXT4_INDIRECT_BLOCKS		12
-- 
2.19.2