[PATCH 05/18] xfs: create a log incompat flag for atomic extent swapping

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Darrick J. Wong <djwong@xxxxxxxxxx>

Create a log incompat flag so that we only attempt to process swap
extent log items if the filesystem supports it.

Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_format.h |   20 ++++++++++++++++++++
 fs/xfs/libxfs/xfs_fs.h     |    1 +
 fs/xfs/libxfs/xfs_sb.c     |    2 ++
 3 files changed, 23 insertions(+)


diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 7e9c964772c9..e81a7b12a0e3 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -485,6 +485,7 @@ xfs_sb_has_incompat_feature(
 	return (sbp->sb_features_incompat & feature) != 0;
 }
 
+#define XFS_SB_FEAT_INCOMPAT_LOG_ATOMIC_SWAP (1 << 0)
 #define XFS_SB_FEAT_INCOMPAT_LOG_ALL 0
 #define XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN	~XFS_SB_FEAT_INCOMPAT_LOG_ALL
 static inline bool
@@ -607,6 +608,25 @@ static inline bool xfs_sb_version_needsrepair(struct xfs_sb *sbp)
 		(sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR);
 }
 
+/*
+ * Decide if this filesystem can use log-assisted ("atomic") extent swapping.
+ * The atomic swap log intent items depend on the block mapping log intent
+ * items introduced with reflink and rmap.  Realtime is not supported yet.
+ */
+static inline bool xfs_sb_version_canatomicswap(struct xfs_sb *sbp)
+{
+	return (xfs_sb_version_hasreflink(sbp) ||
+		xfs_sb_version_hasrmapbt(sbp)) &&
+		!xfs_sb_version_hasrealtime(sbp);
+}
+
+static inline bool xfs_sb_version_hasatomicswap(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
+		(sbp->sb_features_log_incompat &
+		 XFS_SB_FEAT_INCOMPAT_LOG_ATOMIC_SWAP);
+}
+
 /*
  * end of superblock version macros
  */
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index e7e1e3051739..08bfce39407e 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -252,6 +252,7 @@ typedef struct xfs_fsop_resblks {
 #define XFS_FSOP_GEOM_FLAGS_REFLINK	(1 << 20) /* files can share blocks */
 #define XFS_FSOP_GEOM_FLAGS_BIGTIME	(1 << 21) /* 64-bit nsec timestamps */
 #define XFS_FSOP_GEOM_FLAGS_INOBTCNT	(1 << 22) /* inobt btree counter */
+#define XFS_FSOP_GEOM_FLAGS_ATOMIC_SWAP	(1 << 23) /* atomic swapext */
 
 /*
  * Minimum and maximum sizes need for growth checks.
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 6adfe759190c..52791fe33a6e 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -1140,6 +1140,8 @@ xfs_fs_geometry(
 		geo->flags |= XFS_FSOP_GEOM_FLAGS_BIGTIME;
 	if (xfs_sb_version_hasinobtcounts(sbp))
 		geo->flags |= XFS_FSOP_GEOM_FLAGS_INOBTCNT;
+	if (xfs_sb_version_canatomicswap(sbp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_ATOMIC_SWAP;
 	if (xfs_sb_version_hassector(sbp))
 		geo->logsectsize = sbp->sb_logsectsize;
 	else