[PATCH v2 3/9] nilfs2: introduce new feature flag for tracking live blocks

[Andreas Rohner <andreas.rohner-hi6Y0CQ0nG0@public.gmane.org>]

This patch introduces a new file system feature flag
NILFS_FEATURE_COMPAT_TRACK_LIVE_BLKS. If it is enabled, the file system
will keep track of the number of live blocks per segment. This
information can be used by the GC to select segments for cleaning more
efficiently.

Signed-off-by: Andreas Rohner <andreas.rohner-hi6Y0CQ0nG0@public.gmane.org>
---
 fs/nilfs2/the_nilfs.h     | 8 ++++++++
 include/linux/nilfs2_fs.h | 4 +++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index 12cd91d..d755b6b 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -401,4 +401,12 @@ static inline int nilfs_flush_device(struct the_nilfs *nilfs)
 	return err;
 }
 
+static inline int nilfs_feature_track_live_blks(struct the_nilfs *nilfs)
+{
+	const __u64 required_bits = NILFS_FEATURE_COMPAT_TRACK_LIVE_BLKS |
+				    NILFS_FEATURE_COMPAT_SUFILE_LIVE_BLKS_EXT;
+
+	return ((nilfs->ns_feature_compat & required_bits) == required_bits);
+}
+
 #endif /* _THE_NILFS_H */
diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
index 4800daa..5f05bbf 100644
--- a/include/linux/nilfs2_fs.h
+++ b/include/linux/nilfs2_fs.h
@@ -221,11 +221,13 @@ struct nilfs_super_block {
  * doesn't know about, it should refuse to mount the filesystem.
  */
 #define NILFS_FEATURE_COMPAT_SUFILE_LIVE_BLKS_EXT	BIT(0)
+#define NILFS_FEATURE_COMPAT_TRACK_LIVE_BLKS		BIT(1)
 
 #define NILFS_FEATURE_COMPAT_RO_BLOCK_COUNT		BIT(0)
 
 #define NILFS_FEATURE_COMPAT_SUPP					\
-			(NILFS_FEATURE_COMPAT_SUFILE_LIVE_BLKS_EXT)
+			(NILFS_FEATURE_COMPAT_SUFILE_LIVE_BLKS_EXT |	\
+			 NILFS_FEATURE_COMPAT_TRACK_LIVE_BLKS)
 #define NILFS_FEATURE_COMPAT_RO_SUPP	NILFS_FEATURE_COMPAT_RO_BLOCK_COUNT
 #define NILFS_FEATURE_INCOMPAT_SUPP	0ULL
 
-- 
2.3.7

--
To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html