[PATCH 29/29] ubifs: Raise write version to 5

From: Richard Weinberger
Date: Sun Nov 13 2016 - 16:23:46 EST


Starting with version 5 the following properties change:
- UBIFS_FLG_DOUBLE_HASH is mandatory
- UBIFS_FLG_ENCRYPTION is optional but depdens on UBIFS_FLG_DOUBLE_HASH
- Filesystems with unknown super block flags will be rejected, this
allows us in future to add new features without raising the UBIFS
write version.

Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
fs/ubifs/sb.c | 17 +++++++++++++++++
fs/ubifs/ubifs-media.h | 4 +++-
2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index 54cef70ea16f..7f1ead29e727 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -466,6 +466,16 @@ static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
goto failed;
}

+ if (!c->double_hash && c->fmt_version >= 5) {
+ err = 16;
+ goto failed;
+ }
+
+ if (c->encrypted && c->fmt_version < 5) {
+ err = 17;
+ goto failed;
+ }
+
return 0;

failed:
@@ -624,6 +634,13 @@ int ubifs_read_superblock(struct ubifs_info *c)
c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);

+ if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
+ ubifs_err(c, "Unknown feature flags found: %#x",
+ sup_flags & ~UBIFS_FLG_MASK);
+ err = -EINVAL;
+ goto out;
+ }
+
#ifndef CONFIG_UBIFS_FS_ENCRYPTION
if (c->encrypted) {
ubifs_err(c, "file system contains encrypted files but UBIFS"
diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h
index bdc7935a5e41..e8c23c9d4f4a 100644
--- a/fs/ubifs/ubifs-media.h
+++ b/fs/ubifs/ubifs-media.h
@@ -46,7 +46,7 @@
* UBIFS went into mainline kernel with format version 4. The older formats
* were development formats.
*/
-#define UBIFS_FORMAT_VERSION 4
+#define UBIFS_FORMAT_VERSION 5

/*
* Read-only compatibility version. If the UBIFS format is changed, older UBIFS
@@ -429,6 +429,8 @@ enum {
UBIFS_FLG_ENCRYPTION = 0x10,
};

+#define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT|UBIFS_FLG_SPACE_FIXUP|UBIFS_FLG_DOUBLE_HASH|UBIFS_FLG_ENCRYPTION)
+
/**
* struct ubifs_ch - common header node.
* @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC)
--
2.7.3