xfs: check that per-cpu inodegc workers actually run on that cpu

commit b37c4c8339cd394ea6b8b415026603320a185651 upstream.

Now that we've allegedly worked out the problem of the per-cpu inodegc
workers being scheduled on the wrong cpu, let's put in a debugging knob
to let us know if a worker ever gets mis-scheduled again.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 536885f..7ce262d 100644 (file)
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1848,6 +1848,8 @@ xfs_inodegc_worker(
        struct llist_node       *node = llist_del_all(&gc->list);
        struct xfs_inode        *ip, *n;
 
+       ASSERT(gc->cpu == smp_processor_id());
+
        WRITE_ONCE(gc->items, 0);
 
        if (!node)

diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 8aca2cc..69ddd53 100644 (file)
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -66,6 +66,9 @@ struct xfs_inodegc {
        /* approximate count of inodes in the list */
        unsigned int            items;
        unsigned int            shrinker_hits;
+#if defined(DEBUG) || defined(XFS_WARN)
+       unsigned int            cpu;
+#endif
 };
 
 /*

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index ee4b429..4b17952 100644 (file)
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1084,6 +1084,9 @@ xfs_inodegc_init_percpu(
 
        for_each_possible_cpu(cpu) {
                gc = per_cpu_ptr(mp->m_inodegc, cpu);
+#if defined(DEBUG) || defined(XFS_WARN)
+               gc->cpu = cpu;
+#endif
                init_llist_head(&gc->list);
                gc->items = 0;
                INIT_DELAYED_WORK(&gc->work, xfs_inodegc_worker);