iomap: add a tracepoint for mappings returned by map_blocks

Add a new tracepoint so we can see what mapping the filesystem returns
to writeback a dirty page.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 77d59c159248da2562c1c2b2c0d9f94096475aec..91ee0b308e13d3e55368747f81fa19124baf1b18 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1360,6 +1360,7 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
                error = wpc->ops->map_blocks(wpc, inode, pos);
                if (error)
                        break;
+               trace_iomap_writepage_map(inode, &wpc->iomap);
                if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE))
                        continue;
                if (wpc->iomap.type == IOMAP_HOLE)

diff --git a/fs/iomap/trace.h b/fs/iomap/trace.h
index d48868fc40d78f37273365e458a8dd9ea0791423..f6ea9540d082d4eddd37d4cb8d3cc95d07a0dd18 100644 (file)
--- a/fs/iomap/trace.h
+++ b/fs/iomap/trace.h
@@ -148,6 +148,7 @@ DEFINE_EVENT(iomap_class, name,     \
        TP_ARGS(inode, iomap))
 DEFINE_IOMAP_EVENT(iomap_iter_dstmap);
 DEFINE_IOMAP_EVENT(iomap_iter_srcmap);
+DEFINE_IOMAP_EVENT(iomap_writepage_map);
 
 TRACE_EVENT(iomap_iter,
        TP_PROTO(struct iomap_iter *iter, const void *ops,