This is a note to let you know that I've just added the patch titled
afs: Give an afs_server object a ref on the afs_cell object it points to
to the 6.13-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:
afs-give-an-afs_server-object-a-ref-on-the-afs_cell-.patch
and it can be found in the queue-6.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fce175d41fab11e080b88e51ecdaf15c7d33ee2e
Author: David Howells <dhowells@xxxxxxxxxx>
Date: Tue Feb 18 19:22:48 2025 +0000
afs: Give an afs_server object a ref on the afs_cell object it points to
[ Upstream commit 1f0fc3374f3345ff1d150c5c56ac5016e5d3826a ]
Give an afs_server object a ref on the afs_cell object it points to so that
the cell doesn't get deleted before the server record.
Whilst this is circular (cell -> vol -> server_list -> server -> cell), the
ref only pins the memory, not the lifetime as that's controlled by the
activity counter. When the volume's activity counter reaches 0, it
detaches from the cell and discards its server list; when a cell's activity
counter reaches 0, it discards its root volume. At that point, the
circularity is cut.
Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation")
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
cc: Simon Horman <horms@xxxxxxxxxx>
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
Link: https://patch.msgid.link/20250218192250.296870-6-dhowells@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/afs/server.c b/fs/afs/server.c
index 038f9d0ae3af8..4504e16b458cc 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -163,6 +163,8 @@ static struct afs_server *afs_install_server(struct afs_cell *cell,
rb_insert_color(&server->uuid_rb, &net->fs_servers);
hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
+ afs_get_cell(cell, afs_cell_trace_get_server);
+
added_dup:
write_seqlock(&net->fs_addr_lock);
estate = rcu_dereference_protected(server->endpoint_state,
@@ -442,6 +444,7 @@ static void afs_server_rcu(struct rcu_head *rcu)
atomic_read(&server->active), afs_server_trace_free);
afs_put_endpoint_state(rcu_access_pointer(server->endpoint_state),
afs_estate_trace_put_server);
+ afs_put_cell(server->cell, afs_cell_trace_put_server);
kfree(server);
}
diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h
index 9a75590227f26..3dddfc6abf0ee 100644
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -173,6 +173,7 @@ enum yfs_cm_operation {
EM(afs_cell_trace_get_queue_dns, "GET q-dns ") \
EM(afs_cell_trace_get_queue_manage, "GET q-mng ") \
EM(afs_cell_trace_get_queue_new, "GET q-new ") \
+ EM(afs_cell_trace_get_server, "GET server") \
EM(afs_cell_trace_get_vol, "GET vol ") \
EM(afs_cell_trace_insert, "INSERT ") \
EM(afs_cell_trace_manage, "MANAGE ") \
@@ -180,6 +181,7 @@ enum yfs_cm_operation {
EM(afs_cell_trace_put_destroy, "PUT destry") \
EM(afs_cell_trace_put_queue_work, "PUT q-work") \
EM(afs_cell_trace_put_queue_fail, "PUT q-fail") \
+ EM(afs_cell_trace_put_server, "PUT server") \
EM(afs_cell_trace_put_vol, "PUT vol ") \
EM(afs_cell_trace_see_source, "SEE source") \
EM(afs_cell_trace_see_ws, "SEE ws ") \
