Don't open-code "-1" for whichfork when we're creating a staging btree
for a repair; let's define an actual symbol to make grepping and
understanding easier.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
        cur = xfs_bmbt_init_common(mp, NULL, ip, XFS_DATA_FORK);
 
        /* Don't let anyone think we're attached to the real fork yet. */
-       cur->bc_ino.whichfork = -1;
+       cur->bc_ino.whichfork = XFS_STAGING_FORK;
        xfs_btree_stage_ifakeroot(cur, ifake);
        return cur;
 }
 
 /*
  * Inode fork identifiers.
  */
-#define        XFS_DATA_FORK   0
-#define        XFS_ATTR_FORK   1
-#define        XFS_COW_FORK    2
+#define XFS_STAGING_FORK       (-1)    /* fake fork for staging a btree */
+#define        XFS_DATA_FORK           (0)
+#define        XFS_ATTR_FORK           (1)
+#define        XFS_COW_FORK            (2)
 
 #define XFS_WHICHFORK_STRINGS \
+       { XFS_STAGING_FORK,     "staging" }, \
        { XFS_DATA_FORK,        "data" }, \
        { XFS_ATTR_FORK,        "attr" }, \
        { XFS_COW_FORK,         "cow" }