xfs_repair: add prefetch trace calls to debug thread creation failures

When debugging prefetch failures, it's useful to have thread creation
failure messages that are output as warnings on stderr in the trace
log as well.  It's also helpful to see when an AG gets queued behind
another one rather than having the thread started directly, which
has a separate trace line.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/repair/prefetch.c b/repair/prefetch.c
index 044fab2e537bb77bde2d2e9cc50f1f4089a0c198..37d60d67435b994c964d18cd0cebdcbec923cd48 100644 (file)
--- a/repair/prefetch.c
+++ b/repair/prefetch.c
@@ -703,6 +703,8 @@ pf_queuing_worker(
                if (err != 0) {
                        do_warn(_("failed to create prefetch thread: %s\n"),
                                strerror(err));
+                       pftrace("failed to create prefetch thread for AG %d: %s",
+                               args->agno, strerror(err));
                        args->io_threads[i] = 0;
                        if (i == 0) {
                                pf_start_processing(args);
@@ -817,6 +819,8 @@ pf_create_prefetch_thread(
        if (err != 0) {
                do_warn(_("failed to create prefetch thread: %s\n"),
                        strerror(err));
+               pftrace("failed to create prefetch thread for AG %d: %s",
+                       args->agno, strerror(err));
                args->queuing_thread = 0;
                cleanup_inode_prefetch(args);
        }
@@ -882,8 +886,11 @@ start_inode_prefetch(
                if (prev_args->prefetch_done) {
                        if (!pf_create_prefetch_thread(args))
                                args = NULL;
-               } else
+               } else {
                        prev_args->next_args = args;
+                       pftrace("queued AG %d after AG %d",
+                               args->agno, prev_args->agno);
+               }
                pthread_mutex_unlock(&prev_args->lock);
        }