[PATCH 13/43] xfs: add a xfs_rtrmap_highest_rgbno helper

Christoph Hellwig
2025-02-06T06:45:51Z

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>
---
fs/xfs/libxfs/xfs_rtrmap_btree.c | 19 +++++++++++++++++++
fs/xfs/libxfs/xfs_rtrmap_btree.h | 2 ++
2 files changed, 21 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_rtrmap_btree.c b/fs/xfs/libxfs/xfs_rtrmap_btree.c
index e4ec36943cb7..9bdc2cbfc113 100644
--- a/fs/xfs/libxfs/xfs_rtrmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rtrmap_btree.c
@@ -1033,3 +1033,22 @@ 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/fs/xfs/libxfs/xfs_rtrmap_btree.h b/fs/xfs/libxfs/xfs_rtrmap_btree.h
index 9d0915089891..e328fd62a149 100644
--- a/fs/xfs/libxfs/xfs_rtrmap_btree.h
+++ b/fs/xfs/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__ */
--
2.45.2