[PATCH AUTOSEL 4.19 100/237] libceph: don't consume a ref on pagelist in ceph_msg_data_add_pagelist()

Sasha Levin
2019-11-16T16:22:28Z

From: Ilya Dryomov <idryomov@gmail.com>

[ Upstream commit 894868330a1e038ea4a65dbb81741eef70ad71b1 ]

Because send_mds_reconnect() wants to send a message with a pagelist
and pass the ownership to the messenger, ceph_msg_data_add_pagelist()
consumes a ref which is then put in ceph_msg_data_destroy(). This
makes managing pagelists in the OSD client (where they are wrapped in
ceph_osd_data) unnecessarily hard because the handoff only happens in
ceph_osdc_start_request() instead of when the pagelist is passed to
ceph_osd_data_pagelist_init(). I counted several memory leaks on
various error paths.

Fix up ceph_msg_data_add_pagelist() and carry a pagelist ref in
ceph_osd_data.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ceph/mds_client.c | 2 +-
net/ceph/messenger.c | 1 +
net/ceph/osd_client.c | 8 ++++++++
3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 09db6d08614d2..94494d05a94cb 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2184,7 +2184,6 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,

if (req->r_pagelist) {
struct ceph_pagelist *pagelist = req->r_pagelist;
- refcount_inc(&pagelist->refcnt);
ceph_msg_data_add_pagelist(msg, pagelist);
msg->hdr.data_len = cpu_to_le32(pagelist->length);
} else {
@@ -3289,6 +3288,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
mutex_unlock(&mdsc->mutex);

up_read(&mdsc->snap_rwsem);
+ ceph_pagelist_release(pagelist);
return;

fail:
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index f7d7f32ac673c..2c8cd339d59ea 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3323,6 +3323,7 @@ void ceph_msg_data_add_pagelist(struct ceph_msg *msg,

data = ceph_msg_data_create(CEPH_MSG_DATA_PAGELIST);
BUG_ON(!data);
+ refcount_inc(&pagelist->refcnt);
data->pagelist = pagelist;

list_add_tail(&data->links, &msg->data);
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 76c41a84550e7..c3494c1fb3a9a 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -126,6 +126,9 @@ static void ceph_osd_data_init(struct ceph_osd_data *osd_data)
osd_data->type = CEPH_OSD_DATA_TYPE_NONE;
}

+/*
+ * Consumes @pages if @own_pages is true.
+ */
static void ceph_osd_data_pages_init(struct ceph_osd_data *osd_data,
struct page **pages, u64 length, u32 alignment,
bool pages_from_pool, bool own_pages)
@@ -138,6 +141,9 @@ static void ceph_osd_data_pages_init(struct ceph_osd_data *osd_data,
osd_data->own_pages = own_pages;
}

+/*
+ * Consumes a ref on @pagelist.
+ */
static void ceph_osd_data_pagelist_init(struct ceph_osd_data *osd_data,
struct ceph_pagelist *pagelist)
{
@@ -362,6 +368,8 @@ static void ceph_osd_data_release(struct ceph_osd_data *osd_data)
num_pages = calc_pages_for((u64)osd_data->alignment,
(u64)osd_data->length);
ceph_release_page_vector(osd_data->pages, num_pages);
+ } else if (osd_data->type == CEPH_OSD_DATA_TYPE_PAGELIST) {
+ ceph_pagelist_release(osd_data->pagelist);
}
ceph_osd_data_init(osd_data);
}
--
2.20.1