[PATCH v4 09/13] tools/xenstore: add TDB access trace support

[Juergen Gross <jgross@xxxxxxxx>]

Add a new trace switch "tdb" and the related trace calls.

The "tdb" switch is off per default.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 tools/xenstore/xenstored_core.c        | 8 +++++++-
 tools/xenstore/xenstored_core.h        | 7 +++++++
 tools/xenstore/xenstored_transaction.c | 7 ++++++-
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index bd816ce709..2d481fcad9 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -589,6 +589,8 @@ static void get_acc_data(TDB_DATA *key, struct 
node_account_data *acc)
                if (old_data.dptr == NULL) {
                        acc->memory = 0;
                } else {
+                       trace_tdb("read %s size %zu\n", key->dptr,
+                                 old_data.dsize + key->dsize);
                        hdr = (void *)old_data.dptr;
                        acc->memory = old_data.dsize;
                        acc->domid = hdr->perms[0].id;
@@ -655,6 +657,7 @@ int do_tdb_write(struct connection *conn, TDB_DATA *key, 
TDB_DATA *data,
                errno = EIO;
                return errno;
        }
+       trace_tdb("store %s size %zu\n", key->dptr, data->dsize + key->dsize);
 
        if (acc) {
                /* Don't use new_domid, as it might be a transaction node. */
@@ -682,6 +685,7 @@ int do_tdb_delete(struct connection *conn, TDB_DATA *key,
                errno = EIO;
                return errno;
        }
+       trace_tdb("delete %s\n", key->dptr);
 
        if (acc->memory) {
                domid = get_acc_domid(conn, key, acc->domid);
@@ -731,6 +735,8 @@ struct node *read_node(struct connection *conn, const void 
*ctx,
                goto error;
        }
 
+       trace_tdb("read %s size %zu\n", key.dptr, data.dsize + key.dsize);
+
        node->parent = NULL;
        talloc_steal(node, data.dptr);
 
@@ -2746,7 +2752,7 @@ static void set_quota(const char *arg, bool soft)
 
 /* Sorted by bit values of TRACE_* flags. Flag is (1u << index). */
 const char *const trace_switches[] = {
-       "obj", "io", "wrl", "acc",
+       "obj", "io", "wrl", "acc", "tdb",
        NULL
 };
 
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 3e0734a6c6..5a11dc1231 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -303,9 +303,16 @@ extern unsigned int trace_flags;
 #define TRACE_IO       0x00000002
 #define TRACE_WRL      0x00000004
 #define TRACE_ACC      0x00000008
+#define TRACE_TDB      0x00000010
 extern const char *const trace_switches[];
 int set_trace_switch(const char *arg);
 
+#define trace_tdb(...)                         \
+do {                                           \
+       if (trace_flags & TRACE_TDB)            \
+               trace("tdb: " __VA_ARGS__);     \
+} while (0)
+
 extern TDB_CONTEXT *tdb_ctx;
 extern int dom0_domid;
 extern int dom0_event;
diff --git a/tools/xenstore/xenstored_transaction.c 
b/tools/xenstore/xenstored_transaction.c
index 2b15506953..11c8bcec84 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -374,8 +374,11 @@ static int finalize_transaction(struct connection *conn,
                                if (tdb_error(tdb_ctx) != TDB_ERR_NOEXIST)
                                        return EIO;
                                gen = NO_GENERATION;
-                       } else
+                       } else {
+                               trace_tdb("read %s size %zu\n", key.dptr,
+                                         key.dsize + data.dsize);
                                gen = hdr->generation;
+                       }
                        talloc_free(data.dptr);
                        if (i->generation != gen)
                                return EAGAIN;
@@ -399,6 +402,8 @@ static int finalize_transaction(struct connection *conn,
                        set_tdb_key(i->trans_name, &ta_key);
                        data = tdb_fetch(tdb_ctx, ta_key);
                        if (data.dptr) {
+                               trace_tdb("read %s size %zu\n", ta_key.dptr,
+                                         ta_key.dsize + data.dsize);
                                hdr = (void *)data.dptr;
                                hdr->generation = ++generation;
                                *is_corrupt |= do_tdb_write(conn, &key, &data,
-- 
2.35.3