diff options
| author | David Howells <dhowells@redhat.com> | 2018-05-10 08:43:04 +0100 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2018-05-14 13:17:35 +0100 |
| commit | d4a96bec7a7362834ef5c31d7b2cc9bf36eb0570 (patch) | |
| tree | 003ec92ab854c87f1ebbdbb4ee38e7b8a99e870a /fs/afs/internal.h | |
| parent | f2686b09269ec1a6f23028b5675d87c3b4579a4c (diff) | |
afs: Fix refcounting in callback registration
The refcounting on afs_cb_interest struct objects in
afs_register_server_cb_interest() is wrong as it uses the server list
entry's call back interest pointer without regard for the fact that it
might be replaced at any time and the object thrown away.
Fix this by:
(1) Put a lock on the afs_server_list struct that can be used to
mediate access to the callback interest pointers in the servers array.
(2) Keep a ref on the callback interest that we get from the entry.
(3) Dropping the old reference held by vnode->cb_interest if we replace
the pointer.
Fixes: c435ee34551e ("afs: Overhaul the callback handling")
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/afs/internal.h')
| -rw-r--r-- | fs/afs/internal.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 8de04b29bec1..e75e57e13320 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -434,6 +434,7 @@ struct afs_server_list { unsigned short index; /* Server currently in use */ unsigned short vnovol_mask; /* Servers to be skipped due to VNOVOL */ unsigned int seq; /* Set to ->servers_seq when installed */ + rwlock_t lock; struct afs_server_entry servers[]; }; @@ -649,13 +650,15 @@ extern void afs_init_callback_state(struct afs_server *); extern void afs_break_callback(struct afs_vnode *); extern void afs_break_callbacks(struct afs_server *, size_t, struct afs_callback_break*); -extern int afs_register_server_cb_interest(struct afs_vnode *, struct afs_server_entry *); +extern int afs_register_server_cb_interest(struct afs_vnode *, + struct afs_server_list *, unsigned int); extern void afs_put_cb_interest(struct afs_net *, struct afs_cb_interest *); extern void afs_clear_callback_interests(struct afs_net *, struct afs_server_list *); static inline struct afs_cb_interest *afs_get_cb_interest(struct afs_cb_interest *cbi) { - refcount_inc(&cbi->usage); + if (cbi) + refcount_inc(&cbi->usage); return cbi; } |