dlm: fix race between remove and lookup
It was possible for a remove message on an old
rsb to be sent after a lookup message on a new
rsb, where the rsbs were for the same resource
name. This could lead to a missing directory
entry for the new rsb.
It is fixed by keeping a copy of the resource
name being removed until after the remove has
been sent. A lookup checks if this in-progress
remove matches the name it is looking up.
Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index a5f82d5..9d3e485 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -498,6 +498,13 @@
char rl_lvb[0];
};
+/*
+ * The max number of resources per rsbtbl bucket that shrink will attempt
+ * to remove in each iteration.
+ */
+
+#define DLM_REMOVE_NAMES_MAX 8
+
struct dlm_ls {
struct list_head ls_list; /* list of lockspaces */
dlm_lockspace_t *ls_local_handle;
@@ -531,6 +538,12 @@
int ls_new_rsb_count;
struct list_head ls_new_rsb; /* new rsb structs */
+ spinlock_t ls_remove_spin;
+ char ls_remove_name[DLM_RESNAME_MAXLEN+1];
+ char *ls_remove_names[DLM_REMOVE_NAMES_MAX];
+ int ls_remove_len;
+ int ls_remove_lens[DLM_REMOVE_NAMES_MAX];
+
struct list_head ls_nodes; /* current nodes in ls */
struct list_head ls_nodes_gone; /* dead node list, recovery */
int ls_num_nodes; /* number of nodes in ls */