/* Superblock filesystem feature flags (RW compatible)
* A filesystem with any of these enabled can be read and written by a driver
- * that does not understand them without causing metadata/data corruption */
+ * that does not understand them without causing metadata/data corruption. */
#define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001
#define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
/* Superblock filesystem feature flags (RO compatible)
* A filesystem with any of these enabled can be safely read by a driver that
* does not understand them, but should not be written to, usually because
- * additional metadata is required */
+ * additional metadata is required. */
#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
/* Superblock filesystem feature flags (back-incompatible)
* A filesystem with any of these enabled should not be attempted to be read
* by a driver that does not understand them, since they usually indicate
- * metadata format changes that might confuse the reader. */
+ * metadata format changes that might confuse the reader. */
#define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
#define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004 /* Needs recovery */
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
/* The set of back-incompatible features this driver DOES support. Add (OR)
- * flags here as the related features are implemented into the driver */
+ * flags here as the related features are implemented into the driver. */
#define EXT2_DRIVER_SUPPORTED_INCOMPAT ( EXT2_FEATURE_INCOMPAT_FILETYPE \
- | EXT4_FEATURE_INCOMPAT_EXTENTS )
+ | EXT4_FEATURE_INCOMPAT_EXTENTS \
+ | EXT4_FEATURE_INCOMPAT_FLEX_BG )
/* List of rationales for the ignored "incompatible" features:
* needs_recovery: Not really back-incompatible - was added as such to forbid
* ext2 drivers from mounting an ext3 volume with a dirty
* journal because they will ignore the journal, but the next
* ext3 driver to mount the volume will find the journal and
* replay it, potentially corrupting the metadata written by
- * the ext2 drivers
- */
+ * the ext2 drivers. Safe to ignore for this RO driver. */
#define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER )