xfs: Introduce XFS_DIFLAG2_NREXT64 and associated helpers

This commit adds the new per-inode flag XFS_DIFLAG2_NREXT64 to indicate that
an inode supports 64-bit extent counters. This flag is also enabled by default
on newly created inodes when the corresponding filesystem has large extent
counter feature bit (i.e. XFS_FEAT_NREXT64) set.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>

Author: Chandan Babu R

fs/xfs/libxfs/xfs_format.h

@@ -991,22 +991,31 @@ static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
 #define XFS_DIFLAG2_REFLINK_BIT	1	/* file's blocks may be shared */
 #define XFS_DIFLAG2_COWEXTSIZE_BIT   2  /* copy on write extent size hint */
 #define XFS_DIFLAG2_BIGTIME_BIT	3	/* big timestamps */
+#define XFS_DIFLAG2_NREXT64_BIT 4	/* large extent counters */
 
 #define XFS_DIFLAG2_DAX		(1 << XFS_DIFLAG2_DAX_BIT)
 #define XFS_DIFLAG2_REFLINK     (1 << XFS_DIFLAG2_REFLINK_BIT)
 #define XFS_DIFLAG2_COWEXTSIZE  (1 << XFS_DIFLAG2_COWEXTSIZE_BIT)
 #define XFS_DIFLAG2_BIGTIME	(1 << XFS_DIFLAG2_BIGTIME_BIT)
+#define XFS_DIFLAG2_NREXT64	(1 << XFS_DIFLAG2_NREXT64_BIT)
 
 #define XFS_DIFLAG2_ANY \
 	(XFS_DIFLAG2_DAX | XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE | \
-	 XFS_DIFLAG2_BIGTIME)
+	 XFS_DIFLAG2_BIGTIME | XFS_DIFLAG2_NREXT64)
 
 static inline bool xfs_dinode_has_bigtime(const struct xfs_dinode *dip)
 {
 	return dip->di_version >= 3 &&
 	       (dip->di_flags2 & cpu_to_be64(XFS_DIFLAG2_BIGTIME));
 }
 
+static inline bool xfs_dinode_has_large_extent_counts(
+	const struct xfs_dinode *dip)
+{
+	return dip->di_version >= 3 &&
+	       (dip->di_flags2 & cpu_to_be64(XFS_DIFLAG2_NREXT64));
+}
+
 /*
  * Inode number format:
  * low inopblog bits - offset in block

fs/xfs/libxfs/xfs_ialloc.c

@@ -2772,6 +2772,8 @@ xfs_ialloc_setup_geometry(
 	igeo->new_diflags2 = 0;
 	if (xfs_has_bigtime(mp))
 		igeo->new_diflags2 |= XFS_DIFLAG2_BIGTIME;
+	if (xfs_has_large_extent_counts(mp))
+		igeo->new_diflags2 |= XFS_DIFLAG2_NREXT64;
 
 	/* Compute inode btree geometry. */
 	igeo->agino_log = sbp->sb_inopblog + sbp->sb_agblklog;

fs/xfs/xfs_inode.h

@@ -218,6 +218,11 @@ static inline bool xfs_inode_has_bigtime(struct xfs_inode *ip)
 	return ip->i_diflags2 & XFS_DIFLAG2_BIGTIME;
 }
 
+static inline bool xfs_inode_has_large_extent_counts(struct xfs_inode *ip)
+{
+	return ip->i_diflags2 & XFS_DIFLAG2_NREXT64;
+}
+
 /*
  * Return the buftarg used for data allocations on a given inode.
  */

fs/xfs/xfs_inode_item_recover.c

@@ -142,6 +142,13 @@ xfs_log_dinode_to_disk_ts(
 	return ts;
 }
 
+static inline bool xfs_log_dinode_has_large_extent_counts(
+		const struct xfs_log_dinode *ld)
+{
+	return ld->di_version >= 3 &&
+	       (ld->di_flags2 & XFS_DIFLAG2_NREXT64);
+}
+
 STATIC void
 xfs_log_dinode_to_disk(
 	struct xfs_log_dinode	*from,