From: Bob Peterson <rpete...@redhat.com>
In do_promote(), when the glock had no strong holders, we were
accidentally calling demote_incompat_holders() with new_gh == NULL, so
no weak holders were considered incompatible. Instead, the new holder
should have been passed in.
For doing that, the HIF_HOLDER flag needs to be set in new_gh to prevent
may_grant() from complaining. This means that the new holder will now
be recognized as a current holder, so skip over it explicitly in
demote_incompat_holders() to prevent it from being dequeued.
To further clarify things, we can now rename new_gh to current_gh in
demote_incompat_holders(); after all, the HIF_HOLDER flag is already set,
which means the new holder is already a current holder.
Signed-off-by: Bob Peterson <rpete...@redhat.com>
Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
---
fs/gfs2/glock.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 27b519099579..2138460a7369 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -405,10 +405,13 @@ static void do_error(struct gfs2_glock *gl, const int ret)
/**
* demote_incompat_holders - demote incompatible demoteable holders
* @gl: the glock we want to promote
- * @new_gh: the new holder to be promoted
+ * @current_gh: the newly promoted holder
+ *
+ * We're passing the newly promoted holder in @current_gh, but actually, any of
+ * the strong holders would do.
*/
static void demote_incompat_holders(struct gfs2_glock *gl,
- struct gfs2_holder *new_gh)
+ struct gfs2_holder *current_gh)
{
struct gfs2_holder *gh, *tmp;
@@ -424,8 +427,10 @@ static void demote_incompat_holders(struct gfs2_glock *gl,
*/
if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
return;
+ if (gh == current_gh)
+ continue;
if (test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags) &&
- !may_grant(gl, new_gh, gh)) {
+ !may_grant(gl, current_gh, gh)) {
/*
* We should not recurse into do_promote because
* __gfs2_glock_dq only calls handle_callback,
@@ -547,14 +552,14 @@ static int do_promote(struct gfs2_glock *gl)
do_error(gl, 0);
break;
}
+ set_bit(HIF_HOLDER, &gh->gh_iflags);
+ trace_gfs2_promote(gh);
+ gfs2_holder_wake(gh);
if (!incompat_holders_demoted) {
+ current_gh = gh;
demote_incompat_holders(gl, current_gh);
incompat_holders_demoted = true;
- current_gh = gh;
}
- set_bit(HIF_HOLDER, &gh->gh_iflags);
- trace_gfs2_promote(gh);
- gfs2_holder_wake(gh);
}
return 0;
}
--
2.35.1
