This is a note to let you know that I've just added the patch titled
gfs2: Use rhashtable walk interface in glock_hash_walk
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
gfs2-use-rhashtable-walk-interface-in-glock_hash_walk.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Jun 15 09:31:48 CEST 2017
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Date: Tue, 23 May 2017 21:53:36 -0400
Subject: gfs2: Use rhashtable walk interface in glock_hash_walk
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
[ Upstream commit 6a25478077d987edc5e2f880590a2bc5fcab4441 ]
The function glock_hash_walk walks the rhashtable by hand. This
is broken because if it catches the hash table in the middle of
a rehash, then it will miss entries.
This patch replaces the manual walk by using the rhashtable walk
interface.
Fixes: 88ffbf3e037e ("GFS2: Use resizable hash table for glocks")
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/gfs2/glock.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1425,26 +1425,32 @@ static struct shrinker glock_shrinker =
* @sdp: the filesystem
* @bucket: the bucket
*
+ * Note that the function can be called multiple times on the same
+ * object. So the user must ensure that the function can cope with
+ * that.
*/
static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
{
struct gfs2_glock *gl;
- struct rhash_head *pos;
- const struct bucket_table *tbl;
- int i;
-
- rcu_read_lock();
- tbl = rht_dereference_rcu(gl_hash_table.tbl, &gl_hash_table);
- for (i = 0; i < tbl->size; i++) {
- rht_for_each_entry_rcu(gl, pos, tbl, i, gl_node) {
+ struct rhashtable_iter iter;
+
+ rhashtable_walk_enter(&gl_hash_table, &iter);
+
+ do {
+ gl = ERR_PTR(rhashtable_walk_start(&iter));
+ if (gl)
+ continue;
+
+ while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
if ((gl->gl_name.ln_sbd == sdp) &&
lockref_get_not_dead(&gl->gl_lockref))
examiner(gl);
- }
- }
- rcu_read_unlock();
- cond_resched();
+
+ rhashtable_walk_stop(&iter);
+ } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
+
+ rhashtable_walk_exit(&iter);
}
/**
Patches currently in stable-queue which might be from herbert@xxxxxxxxxxxxxxxxxxx are
queue-4.9/gfs2-use-rhashtable-walk-interface-in-glock_hash_walk.patch
queue-4.9/tipc-fix-tipc_sk_reinit-race-conditions.patch