# \[PATCH\] bcache: only check feature sets when sb-\>version \>= BCACHE\_SB\_VERSION\_CDEV\_WITH\_FEATURES

- From: Coly Li \<hidden\>
- Date: 2021-01-28 10:52:47 
- List: linux-block
- Page: https://ratatoskr.run/linux-block/2021/01/6400608
- Thread: https://ratatoskr.run/linux-bcache/2021/01/6400608/t.md

```text
For super block version < BCACHE_SB_VERSION_CDEV_WITH_FEATURES, it
doesn't make sense to check the feature sets. This patch checks
super block version in bch_has_feature_* routines, if the version
doesn't have feature sets yet, returns 0 (false) to the caller.

Fixes: 5342fd425502 ("bcache: set bcache device into read-only mode for BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET") 
Fixes: ffa470327572 ("bcache: add bucket_size_hi into struct cache_sb_disk for large bucket")
Cc: <redacted> # 5.9+
Reported-and-tested-by: Bockholdt Arne <redacted>
Signed-off-by: Coly Li <redacted>
---
 drivers/md/bcache/features.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/md/bcache/features.h b/drivers/md/bcache/features.h
index 84fc2c0f0101..d1c8fd3977fc 100644
--- a/drivers/md/bcache/features.h
+++ b/drivers/md/bcache/features.h
@@ -33,6 +33,8 @@
 #define BCH_FEATURE_COMPAT_FUNCS(name, flagname) \
 static inline int bch_has_feature_##name(struct cache_sb *sb) \
 { \
+	if (sb->version < BCACHE_SB_VERSION_CDEV_WITH_FEATURES) \
+		return 0; \
 	return (((sb)->feature_compat & \
 		BCH##_FEATURE_COMPAT_##flagname) != 0); \
 } \
@@ -50,6 +52,8 @@ static inline void bch_clear_feature_##name(struct cache_sb *sb) \
 #define BCH_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
 static inline int bch_has_feature_##name(struct cache_sb *sb) \
 { \
+	if (sb->version < BCACHE_SB_VERSION_CDEV_WITH_FEATURES) \
+		return 0; \
 	return (((sb)->feature_ro_compat & \
 		BCH##_FEATURE_RO_COMPAT_##flagname) != 0); \
 } \
@@ -67,6 +71,8 @@ static inline void bch_clear_feature_##name(struct cache_sb *sb) \
 #define BCH_FEATURE_INCOMPAT_FUNCS(name, flagname) \
 static inline int bch_has_feature_##name(struct cache_sb *sb) \
 { \
+	if (sb->version < BCACHE_SB_VERSION_CDEV_WITH_FEATURES) \
+		return 0; \
 	return (((sb)->feature_incompat & \
 		BCH##_FEATURE_INCOMPAT_##flagname) != 0); \
 } \
-- 
2.26.2

```