diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c index a0d1a6fbf61e..d7ada90dc048 100644 --- a/fs/lockd/svcsubs.c +++ b/fs/lockd/svcsubs.c @@ -312,12 +312,10 @@ nlm_file_inuse(struct nlm_file *file) return 0; } -static void nlm_close_files(struct nlm_file *file) +static void nlm_file_release(struct nlm_file *file) { - if (file->f_file[O_RDONLY]) - nlmsvc_ops->fclose(file->f_file[O_RDONLY]); - if (file->f_file[O_WRONLY]) - nlmsvc_ops->fclose(file->f_file[O_WRONLY]); + if (!nlm_file_inuse(file)) + nlm_delete_file(file); } /* @@ -327,32 +325,41 @@ static int nlm_traverse_files(void *data, nlm_host_match_fn_t match, int (*is_failover_file)(void *data, struct nlm_file *file)) { - struct hlist_node *next; - struct nlm_file *file; + struct nlm_file *file, *next; int i, ret = 0; mutex_lock(&nlm_file_mutex); for (i = 0; i < FILE_NRHASH; i++) { - hlist_for_each_entry_safe(file, next, &nlm_files[i], f_list) { - if (is_failover_file && !is_failover_file(data, file)) - continue; + file = hlist_entry_safe(nlm_files[i].first, + struct nlm_file, f_list); + if (file) file->f_count++; - mutex_unlock(&nlm_file_mutex); + while (file) { + /* + * Pin the next neighbour before we drop the mutex + * for nlm_inspect_file(); a concurrent + * nlm_release_file() under the same mutex would + * otherwise be free to unlink and kfree it during + * the unlock window, leaving us to dereference a + * freed slab when we walked to next afterwards. + */ + next = hlist_entry_safe(file->f_list.next, + struct nlm_file, f_list); + if (next) + next->f_count++; - /* Traverse locks, blocks and shares of this file - * and update file->f_locks count */ - if (nlm_inspect_file(data, file, match)) - ret = 1; + if (!is_failover_file || is_failover_file(data, file)) { + mutex_unlock(&nlm_file_mutex); - mutex_lock(&nlm_file_mutex); - file->f_count--; - /* No more references to this file. Let go of it. */ - if (list_empty(&file->f_blocks) && !file->f_locks - && !file->f_shares && !file->f_count) { - hlist_del(&file->f_list); - nlm_close_files(file); - kfree(file); + if (nlm_inspect_file(data, file, match)) + ret = 1; + + mutex_lock(&nlm_file_mutex); } + + file->f_count--; + nlm_file_release(file); + file = next; } } mutex_unlock(&nlm_file_mutex);