From: Jeff Layton <jlayton@kernel.org>
To: xiubli@redhat.com
Cc: idryomov@gmail.com, pdonnell@redhat.com, ceph-devel@vger.kernel.org
Subject: Re: [PATCH v2] ceph: correctly release memory from capsnap
Date: Tue, 17 Aug 2021 10:03:56 -0400 [thread overview]
Message-ID: <25dd85fdb777f9b260392ceeda41fc5e62018ddd.camel@kernel.org> (raw)
In-Reply-To: <20210817123517.15764-1-xiubli@redhat.com>
On Tue, 2021-08-17 at 20:35 +0800, xiubli@redhat.com wrote:
> From: Xiubo Li <xiubli@redhat.com>
>
> When force umounting, it will try to remove all the session caps.
> If there has any capsnap is in the flushing list, the remove session
> caps callback will try to release the capsnap->flush_cap memory to
> "ceph_cap_flush_cachep" slab cache, while which is allocated from
> kmalloc-256 slab cache.
>
> At the same time switch to list_del_init() because just in case the
> force umount has removed it from the lists and the
> handle_cap_flushsnap_ack() comes then the seconds list_del_init()
> won't crash the kernel.
>
> URL: https://tracker.ceph.com/issues/52283
> Signed-off-by: Xiubo Li <xiubli@redhat.com>
> ---
>
> - Only to resolve the crash issue.
> - s/list_del/list_del_init/
>
>
> fs/ceph/caps.c | 18 ++++++++++++++----
> fs/ceph/mds_client.c | 7 ++++---
> 2 files changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 990258cbd836..4ee0ef87130a 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -1667,7 +1667,16 @@ int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask,
>
> struct ceph_cap_flush *ceph_alloc_cap_flush(void)
> {
> - return kmem_cache_alloc(ceph_cap_flush_cachep, GFP_KERNEL);
> + struct ceph_cap_flush *cf;
> +
> + cf = kmem_cache_alloc(ceph_cap_flush_cachep, GFP_KERNEL);
> + /*
> + * caps == 0 always means for the capsnap
> + * caps > 0 means dirty caps being flushed
> + * caps == -1 means preallocated, not used yet
> + */
> + cf->caps = -1;
> + return cf;
> }
>
> void ceph_free_cap_flush(struct ceph_cap_flush *cf)
> @@ -1704,14 +1713,14 @@ static bool __finish_cap_flush(struct ceph_mds_client *mdsc,
> prev->wake = true;
> wake = false;
> }
> - list_del(&cf->g_list);
> + list_del_init(&cf->g_list);
> } else if (ci) {
> if (wake && cf->i_list.prev != &ci->i_cap_flush_list) {
> prev = list_prev_entry(cf, i_list);
> prev->wake = true;
> wake = false;
> }
> - list_del(&cf->i_list);
> + list_del_init(&cf->i_list);
> } else {
> BUG_ON(1);
> }
> @@ -3398,7 +3407,8 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
> cf = list_first_entry(&to_remove,
> struct ceph_cap_flush, i_list);
> list_del(&cf->i_list);
> - ceph_free_cap_flush(cf);
> + if (cf->caps)
> + ceph_free_cap_flush(cf);
> }
>
> if (wake_ci)
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 2c3d762c7973..dc30f56115fa 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -1226,7 +1226,7 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
> spin_lock(&mdsc->cap_dirty_lock);
>
> list_for_each_entry(cf, &to_remove, i_list)
> - list_del(&cf->g_list);
> + list_del_init(&cf->g_list);
>
> if (!list_empty(&ci->i_dirty_item)) {
> pr_warn_ratelimited(
> @@ -1266,8 +1266,9 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
> struct ceph_cap_flush *cf;
> cf = list_first_entry(&to_remove,
> struct ceph_cap_flush, i_list);
> - list_del(&cf->i_list);
> - ceph_free_cap_flush(cf);
> + list_del_init(&cf->i_list);
> + if (cf->caps)
> + ceph_free_cap_flush(cf);
> }
>
> wake_up_all(&ci->i_cap_wq);
This patch doesn't seem to apply to the current testing branch. Is it
against an older tree?
--
Jeff Layton <jlayton@kernel.org>
next prev parent reply other threads:[~2021-08-17 14:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-17 12:35 [PATCH v2] ceph: correctly release memory from capsnap xiubli
2021-08-17 14:03 ` Jeff Layton [this message]
2021-08-18 1:28 ` Xiubo Li
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