xfs: add a xfs_rtrmap_highest_rgbno helper

Source kernel commit: aacde95a37160b1462e46e0fd0cc7fd70e3bf1cc

Add a helper to find the last offset mapped in the rtrmap.  This will be
used by the zoned code to find out where to start writing again on
conventional devices without hardware zone support.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/libxfs/xfs_rtrmap_btree.c b/libxfs/xfs_rtrmap_btree.c
index d897d140efa75344374d6ba73ee8a82176b97d82..d46fb67bb5d4285bcbb52afb60aa4dcb599fb64d 100644 (file)
--- a/libxfs/xfs_rtrmap_btree.c
+++ b/libxfs/xfs_rtrmap_btree.c
@@ -1032,3 +1032,22 @@ xfs_rtrmapbt_init_rtsb(
        xfs_btree_del_cursor(cur, error);
        return error;
 }
+
+/*
+ * Return the highest rgbno currently tracked by the rmap for this rtg.
+ */
+xfs_rgblock_t
+xfs_rtrmap_highest_rgbno(
+       struct xfs_rtgroup      *rtg)
+{
+       struct xfs_btree_block  *block = rtg_rmap(rtg)->i_df.if_broot;
+       union xfs_btree_key     key = {};
+       struct xfs_btree_cur    *cur;
+
+       if (block->bb_numrecs == 0)
+               return NULLRGBLOCK;
+       cur = xfs_rtrmapbt_init_cursor(NULL, rtg);
+       xfs_btree_get_keys(cur, block, &key);
+       xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
+       return be32_to_cpu(key.__rmap_bigkey[1].rm_startblock);
+}

diff --git a/libxfs/xfs_rtrmap_btree.h b/libxfs/xfs_rtrmap_btree.h
index 9d0915089891a5edc77c9c170ed83e10cb1ff21d..e328fd62a149d12bd52cbb08cb9387ef24adc8f3 100644 (file)
--- a/libxfs/xfs_rtrmap_btree.h
+++ b/libxfs/xfs_rtrmap_btree.h
@@ -207,4 +207,6 @@ struct xfs_btree_cur *xfs_rtrmapbt_mem_cursor(struct xfs_rtgroup *rtg,
 int xfs_rtrmapbt_mem_init(struct xfs_mount *mp, struct xfbtree *xfbtree,
                struct xfs_buftarg *btp, xfs_rgnumber_t rgno);
 
+xfs_rgblock_t xfs_rtrmap_highest_rgbno(struct xfs_rtgroup *rtg);
+
 #endif /* __XFS_RTRMAP_BTREE_H__ */