#include <errno.h>
#include <signal.h>
#include <assert.h>
+#include <fcntl.h>
#define STRINGIFY2(x) #x
#define STRINGIFY(x) STRINGIFY2(x)
/* Avoid mod by zero */
static unsigned int total_keys = 1;
-#define DEBUG_DEPS 1
+/* #define DEBUG_DEPS 1 */
/* Traversals block transactions in the current implementation. */
#define TRAVERSALS_TAKE_TRANSACTION_LOCK 1
int fd[2];
};
static struct pipe *pipes;
+static int backoff_fd = -1;
static void __attribute__((noreturn)) fail(const char *filename,
unsigned int line,
OP_TDB_TRAVERSE_START,
OP_TDB_TRAVERSE_END,
OP_TDB_TRAVERSE,
+ OP_TDB_TRAVERSE_END_EARLY,
OP_TDB_FIRSTKEY,
OP_TDB_NEXTKEY,
OP_TDB_FETCH,
};
struct op {
- unsigned int serial;
- enum op_type op;
+ unsigned int seqnum;
+ enum op_type type;
TDB_DATA key;
TDB_DATA data;
int ret;
TDB_DATA pre;
TDB_DATA post;
} append;
- unsigned int group_len; /* transaction/traverse start */
+ /* transaction/traverse start/chainlock */
+ unsigned int group_len;
};
};
+struct op_desc {
+ unsigned int file;
+ unsigned int op_num;
+};
+
static unsigned char hex_char(const char *filename, unsigned int line, char c)
{
c = toupper(c);
}
static void add_op(const char *filename, struct op **op, unsigned int i,
- unsigned int serial, enum op_type type)
+ unsigned int seqnum, enum op_type type)
{
struct op *new;
*op = talloc_realloc(NULL, *op, struct op, i+1);
new = (*op) + i;
- new->op = type;
- new->serial = serial;
+ new->type = type;
+ new->seqnum = seqnum;
new->ret = 0;
new->group_start = 0;
}
fail(filename, op_num+1, "Expected just a key");
op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
- if (op[op_num].op != OP_TDB_TRAVERSE)
- total_keys++;
+ total_keys++;
}
static void op_add_key_ret(const char *filename,
total_keys++;
}
-/* <serial> tdb_store <rec> <rec> <flag> = <ret> */
+/* We don't record the keys or data for a traverse, as we don't use them. */
+static void op_add_traverse(const char *filename,
+ struct op op[], unsigned int op_num, char *words[])
+{
+ if (!words[2] || !words[3] || !words[4] || words[5]
+ || !streq(words[3], "="))
+ fail(filename, op_num+1, "Expected <key> = <data>");
+ op[op_num].key = tdb_null;
+}
+
+/* Full traverse info is useful for debugging, but changing it to
+ * "traversefn" without the data makes the traces *much* smaller! */
+static void op_add_traversefn(const char *filename,
+ struct op op[], unsigned int op_num, char *words[])
+{
+ if (words[2])
+ fail(filename, op_num+1, "Expected no values");
+ op[op_num].key = tdb_null;
+}
+
+/* <seqnum> tdb_store <rec> <rec> <flag> = <ret> */
static void op_add_store(const char *filename,
struct op op[], unsigned int op_num, char *words[])
{
total_keys++;
}
-/* <serial> tdb_append <rec> <rec> = <rec> */
+/* <seqnum> tdb_append <rec> <rec> = <rec> */
static void op_add_append(const char *filename,
struct op op[], unsigned int op_num, char *words[])
{
total_keys++;
}
-/* <serial> tdb_get_seqnum = <ret> */
+/* <seqnum> tdb_get_seqnum = <ret> */
static void op_add_seqnum(const char *filename,
struct op op[], unsigned int op_num, char *words[])
{
op[op_num].ret = atoi(words[3]);
}
-static void op_add_traverse(const char *filename,
- struct op op[], unsigned int op_num, char *words[])
+static void op_add_traverse_start(const char *filename,
+ struct op op[],
+ unsigned int op_num, char *words[])
{
if (words[2])
fail(filename, op_num+1, "Expect no arguments");
op[op_num].group_len = 0;
}
-static int op_transaction_start(struct op op[], unsigned int op_num)
+static void op_add_chainlock(const char *filename,
+ struct op op[], unsigned int op_num, char *words[])
+{
+ if (words[2] == NULL || words[3])
+ fail(filename, op_num+1, "Expected just a key");
+
+ /* A chainlock key isn't a key in the normal sense; it doesn't
+ * have to be in the db at all. Also, we don't want to hash this op. */
+ op[op_num].data = make_tdb_data(op, filename, op_num+1, words[2]);
+ op[op_num].key = tdb_null;
+ op[op_num].group_len = 0;
+}
+
+static void op_add_chainlock_ret(const char *filename,
+ struct op op[], unsigned int op_num,
+ char *words[])
+{
+ if (!words[2] || !words[3] || !words[4] || words[5]
+ || !streq(words[3], "="))
+ fail(filename, op_num+1, "Expected <key> = <ret>");
+ op[op_num].ret = atoi(words[4]);
+ op[op_num].data = make_tdb_data(op, filename, op_num+1, words[2]);
+ op[op_num].key = tdb_null;
+ op[op_num].group_len = 0;
+ total_keys++;
+}
+
+static int op_find_start(struct op op[], unsigned int op_num, enum op_type type)
{
unsigned int i;
for (i = op_num-1; i > 0; i--) {
- if (op[i].op == OP_TDB_TRANSACTION_START && !op[i].group_len)
+ if (op[i].type == type && !op[i].group_len)
return i;
}
return 0;
if (words[2])
fail(filename, op_num+1, "Expect no arguments");
- start = op_transaction_start(op, op_num);
+ start = op_find_start(op, op_num, OP_TDB_TRANSACTION_START);
if (!start)
fail(filename, op_num+1, "no transaction start found");
op[i].group_start = start;
}
-struct traverse_hash {
- TDB_DATA key;
- unsigned int index;
-};
+/* We treat chainlocks a lot like transactions, even though that's overkill */
+static void op_analyze_chainlock(const char *filename,
+ struct op op[], unsigned int op_num,
+ char *words[])
+{
+ unsigned int i, start;
+
+ if (words[2] == NULL || words[3])
+ fail(filename, op_num+1, "Expected just a key");
+
+ op[op_num].data = make_tdb_data(op, filename, op_num+1, words[2]);
+ op[op_num].key = tdb_null;
+ total_keys++;
+
+ start = op_find_start(op, op_num, OP_TDB_CHAINLOCK);
+ if (!start)
+ start = op_find_start(op, op_num, OP_TDB_CHAINLOCK_READ);
+ if (!start)
+ fail(filename, op_num+1, "no initial chainlock found");
+
+ /* FIXME: We'd have to do something clever to make this work
+ * vs. deadlock. */
+ if (!key_eq(op[start].data, op[op_num].data))
+ fail(filename, op_num+1, "nested chainlock calls?");
+
+ op[start].group_len = op_num - start;
+ for (i = start; i <= op_num; i++)
+ op[i].group_start = start;
+}
static void op_analyze_traverse(const char *filename,
struct op op[], unsigned int op_num,
} else
op[op_num].ret = 0;
- for (i = op_num-1; i >= 0; i--) {
- if (op[i].op != OP_TDB_TRAVERSE_READ_START
- && op[i].op != OP_TDB_TRAVERSE_START)
- continue;
- if (op[i].group_len)
- continue;
- break;
- }
-
- if (i < 0)
+ start = op_find_start(op, op_num, OP_TDB_TRAVERSE_START);
+ if (!start)
+ start = op_find_start(op, op_num, OP_TDB_TRAVERSE_READ_START);
+ if (!start)
fail(filename, op_num+1, "no traversal start found");
- start = i;
op[start].group_len = op_num - start;
+ /* Don't roll in nested traverse/chainlock */
for (i = start; i <= op_num; i++)
- op[i].group_start = start;
+ if (!op[i].group_start)
+ op[i].group_start = start;
}
/* Keep -Wmissing-declarations happy: */
/* We can have more than one */
struct list_node pre_list;
struct list_node post_list;
- unsigned int needs_file;
- unsigned int needs_opnum;
- unsigned int satisfies_file;
- unsigned int satisfies_opnum;
+ struct op_desc needs;
+ struct op_desc prereq;
};
static void check_deps(const char *filename, struct op op[], unsigned int num)
struct depend *dep;
printf("%s:%u (%u) still waiting for:\n", filename[file], i+1,
- op[file][i].serial);
+ op[file][i].seqnum);
list_for_each(&op[file][i].pre, dep, pre_list)
printf(" %s:%u (%u)\n",
- filename[dep->satisfies_file], dep->satisfies_opnum+1,
- op[dep->satisfies_file][dep->satisfies_opnum].serial);
+ filename[dep->prereq.file], dep->prereq.op_num+1,
+ op[dep->prereq.file][dep->prereq.op_num].seqnum);
check_deps(filename[file], op[file], i);
}
/* We simply read/write pointers, since we all are children. */
-static void do_pre(struct tdb_context *tdb,
+static bool do_pre(struct tdb_context *tdb,
char *filename[], struct op *op[],
- unsigned int file, int pre_fd, unsigned int i)
+ unsigned int file, int pre_fd, unsigned int i,
+ bool backoff)
{
while (!list_empty(&op[file][i].pre)) {
struct depend *dep;
printf("%s:%u:waiting for pre\n", filename[file], i+1);
fflush(stdout);
#endif
- alarm(10);
+ if (backoff)
+ alarm(2);
+ else
+ alarm(10);
while (read(pre_fd, &dep, sizeof(dep)) != sizeof(dep)) {
if (errno == EINTR) {
+ if (backoff) {
+ struct op_desc desc = { file,i };
+ warnx("%s:%u:avoiding deadlock",
+ filename[file], i+1);
+ if (write(backoff_fd, &desc,
+ sizeof(desc)) != sizeof(desc))
+ err(1, "writing backoff_fd");
+ return false;
+ }
dump_pre(filename, op, file, i);
exit(1);
} else
#if DEBUG_DEPS
printf("%s:%u:got pre %u from %s:%u\n", filename[file], i+1,
- dep->needs_opnum+1, filename[dep->satisfies_file],
- dep->satisfies_opnum+1);
+ dep->needs.op_num+1, filename[dep->prereq.file],
+ dep->prereq.op_num+1);
fflush(stdout);
#endif
/* This could be any op, not just this one. */
talloc_free(dep);
}
+ return true;
}
static void do_post(char *filename[], struct op *op[],
list_for_each(&op[file][i].post, dep, post_list) {
#if DEBUG_DEPS
printf("%s:%u:sending to file %s:%u\n", filename[file], i+1,
- filename[dep->needs_file], dep->needs_opnum+1);
+ filename[dep->needs.file], dep->needs.op_num+1);
#endif
- if (write(pipes[dep->needs_file].fd[1], &dep, sizeof(dep))
+ if (write(pipes[dep->needs.file].fd[1], &dep, sizeof(dep))
!= sizeof(dep))
err(1, "%s:%u failed to tell file %s",
- filename[file], i+1, filename[dep->needs_file]);
+ filename[file], i+1, filename[dep->needs.file]);
}
}
char *filename[],
struct op *op[],
unsigned int file,
- unsigned int start, unsigned int stop);
+ unsigned int start, unsigned int stop,
+ bool backoff);
struct traverse_info {
struct op **op;
{
struct traverse_info *tinfo = _tinfo;
unsigned int trav_len = tinfo->op[tinfo->file][tinfo->start].group_len;
+ bool avoid_deadlock = false;
if (tinfo->i == tinfo->start + trav_len) {
/* This can happen if traverse expects to be empty. */
"traverse did not terminate");
}
- if (tinfo->op[tinfo->file][tinfo->i].op != OP_TDB_TRAVERSE)
+ if (tinfo->op[tinfo->file][tinfo->i].type != OP_TDB_TRAVERSE)
fail(tinfo->filename[tinfo->file], tinfo->start + 1,
"%s:%u:traverse terminated early");
+#if TRAVERSALS_TAKE_TRANSACTION_LOCK
+ avoid_deadlock = true;
+#endif
+
/* Run any normal ops. */
tinfo->i = run_ops(tdb, tinfo->pre_fd, tinfo->filename, tinfo->op,
- tinfo->file, tinfo->i+1, tinfo->start + trav_len);
+ tinfo->file, tinfo->i+1, tinfo->start + trav_len,
+ avoid_deadlock);
- if (tinfo->i == tinfo->start + trav_len)
+ /* We backed off, or we hit OP_TDB_TRAVERSE_END/EARLY. */
+ if (tinfo->op[tinfo->file][tinfo->i].type != OP_TDB_TRAVERSE)
return 1;
return 0;
* original traverse went A (delete A), B, we might do B
* (delete A). So if we have ops left over, we do it now. */
while (tinfo.i != start + op[file][start].group_len) {
- if (op[file][tinfo.i].op == OP_TDB_TRAVERSE)
+ if (op[file][tinfo.i].type == OP_TDB_TRAVERSE
+ || op[file][tinfo.i].type == OP_TDB_TRAVERSE_END_EARLY)
tinfo.i++;
else
tinfo.i = run_ops(tdb, pre_fd, filename, op, file,
tinfo.i,
- start + op[file][start].group_len);
+ start + op[file][start].group_len,
+ false);
}
return tinfo.i;
char *filename[],
struct op *op[],
unsigned int file,
- unsigned int start, unsigned int stop)
+ unsigned int start, unsigned int stop,
+ bool backoff)
{
unsigned int i;
struct sigaction sa;
sigaction(SIGALRM, &sa, NULL);
for (i = start; i < stop; i++) {
- do_pre(tdb, filename, op, file, pre_fd, i);
+ if (!do_pre(tdb, filename, op, file, pre_fd, i, backoff))
+ return i;
- switch (op[file][i].op) {
+ switch (op[file][i].type) {
case OP_TDB_LOCKALL:
try(tdb_lockall(tdb), op[file][i].ret);
break;
tdb_traverse, op, i);
break;
case OP_TDB_TRAVERSE:
+ case OP_TDB_TRAVERSE_END_EARLY:
/* Terminate: we're in a traverse, and we've
* done our ops. */
return i;
static struct op *maybe_cancel_transaction(const char *filename,
struct op *op, unsigned int *num)
{
- unsigned int start = op_transaction_start(op, *num);
+ unsigned int start = op_find_start(op, *num, OP_TDB_TRANSACTION_START);
if (start) {
char *words[] = { "<unknown>", "tdb_close", NULL };
- add_op(filename, &op, *num, op[start].serial,
+ add_op(filename, &op, *num, op[start].seqnum,
OP_TDB_TRANSACTION_CANCEL);
op_analyze_transaction(filename, op, *num, words);
(*num)++;
words = strsplit(lines, lines[i], " ", NULL);
if (!words[0] || !words[1])
- fail(filename, i+1, "Expected serial number and op");
+ fail(filename, i+1, "Expected seqnum number and op");
opt = find_keyword(words[1], strlen(words[1]));
if (!opt) {
}
/* We remember all the keys we've ever seen, and who has them. */
-struct key_user {
- unsigned int file;
- unsigned int op_num;
-};
-
struct keyinfo {
TDB_DATA key;
unsigned int num_users;
- struct key_user *user;
+ struct op_desc *user;
};
static const TDB_DATA must_not_exist;
* not exist, otherwise the data it needs. */
static const TDB_DATA *needs(const struct op *op)
{
- switch (op->op) {
+ switch (op->type) {
/* FIXME: Pull forward deps, since we can deadlock */
case OP_TDB_CHAINLOCK:
case OP_TDB_CHAINLOCK_NONBLOCK:
return &must_exist;
default:
- errx(1, "Unexpected op %i", op->op);
+ errx(1, "Unexpected op type %i", op->type);
}
}
+static bool starts_transaction(const struct op *op)
+{
+ return op->type == OP_TDB_TRANSACTION_START;
+}
+
+static bool in_transaction(const struct op op[], unsigned int i)
+{
+ return op[i].group_start && starts_transaction(&op[op[i].group_start]);
+}
+
+static bool successful_transaction(const struct op *op)
+{
+ return starts_transaction(op)
+ && op[op->group_len].type == OP_TDB_TRANSACTION_COMMIT;
+}
+
+static bool starts_traverse(const struct op *op)
+{
+ return op->type == OP_TDB_TRAVERSE_START
+ || op->type == OP_TDB_TRAVERSE_READ_START;
+}
+
+static bool in_traverse(const struct op op[], unsigned int i)
+{
+ return op[i].group_start && starts_traverse(&op[op[i].group_start]);
+}
+
+static bool starts_chainlock(const struct op *op)
+{
+ return op->type == OP_TDB_CHAINLOCK_READ
+ || op->type == OP_TDB_CHAINLOCK;
+}
+
+static bool in_chainlock(const struct op op[], unsigned int i)
+{
+ return op[i].group_start && starts_chainlock(&op[op[i].group_start]);
+}
+
/* What's the data after this op? pre if nothing changed. */
-static const TDB_DATA *gives(const struct op *op, const TDB_DATA *pre)
+static const TDB_DATA *gives(const TDB_DATA *key, const TDB_DATA *pre,
+ const struct op *op)
{
+ if (starts_transaction(op) || starts_chainlock(op)) {
+ unsigned int i;
+
+ /* Cancelled transactions don't change anything. */
+ if (op[op->group_len].type == OP_TDB_TRANSACTION_CANCEL)
+ return pre;
+ assert(op[op->group_len].type == OP_TDB_TRANSACTION_COMMIT
+ || op[op->group_len].type == OP_TDB_CHAINUNLOCK_READ
+ || op[op->group_len].type == OP_TDB_CHAINUNLOCK);
+
+ for (i = 1; i < op->group_len; i++) {
+ /* This skips nested transactions, too */
+ if (key_eq(op[i].key, *key))
+ pre = gives(key, pre, &op[i]);
+ }
+ return pre;
+ }
+
/* Failed ops don't change state of db. */
if (op->ret < 0)
return pre;
- if (op->op == OP_TDB_DELETE || op->op == OP_TDB_WIPE_ALL)
+ if (op->type == OP_TDB_DELETE || op->type == OP_TDB_WIPE_ALL)
return &tdb_null;
- if (op->op == OP_TDB_APPEND)
+ if (op->type == OP_TDB_APPEND)
return &op->append.post;
- if (op->op == OP_TDB_STORE)
+ if (op->type == OP_TDB_STORE)
return &op->data;
return pre;
if (!op[i][j].key.dptr)
continue;
- /* We don't wait for traverse keys */
- /* FIXME: We should, for trivial traversals. */
- if (op[i][j].op == OP_TDB_TRAVERSE)
- continue;
-
h = hash_key(&op[i][j].key) % (total_keys * 2);
while (!key_eq(hash[h].key, op[i][j].key)) {
if (!hash[h].key.dptr) {
op[i][j].key.dptr = hash[h].key.dptr;
}
hash[h].user = talloc_realloc(hash, hash[h].user,
- struct key_user,
+ struct op_desc,
hash[h].num_users+1);
- hash[h].user[hash[h].num_users].op_num = j;
+
+ /* If it's in a transaction, it's the transaction which
+ * matters from an analysis POV. */
+ if (in_transaction(op[i], j)
+ || in_chainlock(op[i], j)) {
+ unsigned start = op[i][j].group_start;
+
+ /* Don't include twice. */
+ if (hash[h].num_users
+ && hash[h].user[hash[h].num_users-1].file
+ == i
+ && hash[h].user[hash[h].num_users-1].op_num
+ == start)
+ continue;
+
+ hash[h].user[hash[h].num_users].op_num = start;
+ } else
+ hash[h].user[hash[h].num_users].op_num = j;
hash[h].user[hash[h].num_users].file = i;
hash[h].num_users++;
}
return hash;
}
-static bool satisfies(const TDB_DATA *data, const TDB_DATA *need)
+static bool satisfies(const TDB_DATA *key, const TDB_DATA *data,
+ const struct op *op)
{
+ const TDB_DATA *need = NULL;
+
+ if (starts_transaction(op) || starts_chainlock(op)) {
+ unsigned int i;
+
+ /* Look through for an op in this transaction which
+ * needs this key. */
+ for (i = 1; i < op->group_len; i++) {
+ if (key_eq(op[i].key, *key)) {
+ need = needs(&op[i]);
+ /* tdb_exists() is special: there might be
+ * something in the transaction with more
+ * specific requirements. Other ops don't have
+ * specific requirements (eg. store or delete),
+ * but they change the value so we can't get
+ * more information from future ops. */
+ if (op[i].type != OP_TDB_EXISTS)
+ break;
+ }
+ }
+ } else
+ need = needs(op);
+
/* Don't need anything? Cool. */
if (!need)
return true;
assert(data != &must_not_exist);
assert(data != ¬_exists_or_empty);
- /* must_not_exist == must_not_exist, must_exist == must_exist, or
- not_exists_or_empty == not_exists_or_empty. */
- if (data->dsize == need->dsize && data->dptr == need->dptr)
- return true;
-
/* Must not exist? data must not exist. */
if (need == &must_not_exist)
- return data->dptr == NULL;
+ return data == &tdb_null;
/* Must exist? */
if (need == &must_exist)
- return data->dptr != NULL;
+ return data != &tdb_null;
/* Either noexist or empty. */
if (need == ¬_exists_or_empty)
return key_eq(*data, *need);
}
-static void move_to_front(struct key_user res[], unsigned int elem)
+static void move_to_front(struct op_desc res[], unsigned off, unsigned elem)
{
- if (elem != 0) {
- struct key_user tmp = res[elem];
- memmove(res + 1, res, elem*sizeof(res[0]));
- res[0] = tmp;
+ if (elem != off) {
+ struct op_desc tmp = res[elem];
+ memmove(res + off + 1, res + off, (elem - off)*sizeof(res[0]));
+ res[off] = tmp;
}
}
-static void restore_to_pos(struct key_user res[], unsigned int elem)
+static void restore_to_pos(struct op_desc res[], unsigned off, unsigned elem)
{
- if (elem != 0) {
- struct key_user tmp = res[0];
- memmove(res, res + 1, elem*sizeof(res[0]));
+ if (elem != off) {
+ struct op_desc tmp = res[off];
+ memmove(res + off, res + off + 1, (elem - off)*sizeof(res[0]));
res[elem] = tmp;
}
}
static bool sort_deps(char *filename[], struct op *op[],
- struct key_user res[], unsigned num,
- const TDB_DATA *data, unsigned num_files)
+ struct op_desc res[],
+ unsigned off, unsigned num,
+ const TDB_DATA *key, const TDB_DATA *data,
+ unsigned num_files, unsigned fuzz)
{
unsigned int i, files_done;
struct op *this_op;
bool done[num_files];
- /* Nothing left? We're sorted. */
- if (num == 0)
+ /* None left? We're sorted. */
+ if (off == num)
return true;
+ /* Does this make sequence number go backwards? Allow a little fuzz. */
+ if (off > 0) {
+ int seqnum1 = op[res[off-1].file][res[off-1].op_num].seqnum;
+ int seqnum2 = op[res[off].file][res[off].op_num].seqnum;
+
+ if (seqnum1 - seqnum2 > (int)fuzz) {
+#if DEBUG_DEPS
+ printf("Seqnum jump too far (%u -> %u)\n",
+ seqnum1, seqnum2);
+#endif
+ return false;
+ }
+ }
+
memset(done, 0, sizeof(done));
/* Since ops within a trace file are ordered, we just need to figure
* out which file to try next. Since we don't take into account
* inter-key relationships (which exist by virtue of trace file order),
- * we minimize the chance of harm by trying to keep in serial order. */
- for (files_done = 0, i = 0; i < num && files_done < num_files; i++) {
+ * we minimize the chance of harm by trying to keep in seqnum order. */
+ for (files_done = 0, i = off; i < num && files_done < num_files; i++) {
if (done[res[i].file])
continue;
this_op = &op[res[i].file][res[i].op_num];
+
/* Is what we have good enough for this op? */
- if (satisfies(data, needs(this_op))) {
- move_to_front(res, i);
- if (sort_deps(filename, op, res+1, num-1,
- gives(this_op, data), num_files))
+ if (satisfies(key, data, this_op)) {
+ move_to_front(res, off, i);
+ if (sort_deps(filename, op, res, off+1, num,
+ key, gives(key, data, this_op),
+ num_files, fuzz))
return true;
- restore_to_pos(res, i);
+ restore_to_pos(res, off, i);
}
done[res[i].file] = true;
files_done++;
return false;
}
-static void check_dep_sorting(struct key_user user[], unsigned num_users,
+static void check_dep_sorting(struct op_desc user[], unsigned num_users,
unsigned num_files)
{
#if DEBUG_DEPS
/* All these ops happen on the same key. Which comes first?
*
* This can happen both because read ops or failed write ops don't
- * change serial number, and also due to race since we access the
+ * change sequence number, and also due to race since we access the
* number unlocked (the race can cause less detectable ordering problems,
* in which case we'll deadlock and report: fix manually in that case).
*/
static void figure_deps(char *filename[], struct op *op[],
- struct key_user user[], unsigned num_users,
- unsigned num_files)
+ const TDB_DATA *key, struct op_desc user[],
+ unsigned num_users, unsigned num_files)
{
/* We assume database starts empty. */
const struct TDB_DATA *data = &tdb_null;
+ unsigned int fuzz;
+
+ /* We prefer to keep strict seqnum order if possible: it's the
+ * most likely. We get more lax if that fails. */
+ for (fuzz = 0; fuzz < 100; fuzz = (fuzz + 1)*2) {
+ if (sort_deps(filename, op, user, 0, num_users, key, data,
+ num_files, fuzz))
+ break;
+ }
- if (!sort_deps(filename, op, user, num_users, data, num_files))
+ if (fuzz >= 100)
fail(filename[user[0].file], user[0].op_num+1,
"Could not resolve inter-dependencies");
unsigned int h;
/* Gcc nexted function extension. How cool is this? */
- int compare_serial(const void *_a, const void *_b)
+ int compare_seqnum(const void *_a, const void *_b)
{
- const struct key_user *a = _a, *b = _b;
+ const struct op_desc *a = _a, *b = _b;
/* First, maintain order within any trace file. */
if (a->file == b->file)
return a->op_num - b->op_num;
- /* Otherwise, arrange by serial order. */
- return op[a->file][a->op_num].serial
- - op[b->file][b->op_num].serial;
+ /* Otherwise, arrange by seqnum order. */
+ if (op[a->file][a->op_num].seqnum !=
+ op[b->file][b->op_num].seqnum)
+ return op[a->file][a->op_num].seqnum
+ - op[b->file][b->op_num].seqnum;
+
+ /* Cancelled transactions are assumed to happen first. */
+ if (starts_transaction(&op[a->file][a->op_num])
+ && !successful_transaction(&op[a->file][a->op_num]))
+ return -1;
+ if (starts_transaction(&op[b->file][b->op_num])
+ && !successful_transaction(&op[b->file][b->op_num]))
+ return 1;
+
+ /* No idea. */
+ return 0;
}
- /* Now sort into serial order. */
+ /* Now sort into seqnum order. */
for (h = 0; h < total_keys * 2; h++) {
- struct key_user *user = hash[h].user;
+ struct op_desc *user = hash[h].user;
- qsort(user, hash[h].num_users, sizeof(user[0]), compare_serial);
- figure_deps(filename, op, user, hash[h].num_users, num);
+ qsort(user, hash[h].num_users, sizeof(user[0]), compare_seqnum);
+ figure_deps(filename, op, &hash[h].key, user, hash[h].num_users,
+ num);
}
}
static void add_dependency(void *ctx,
struct op *op[],
char *filename[],
- unsigned int needs_file,
- unsigned int needs_opnum,
- unsigned int satisfies_file,
- unsigned int satisfies_opnum)
+ const struct op_desc *needs,
+ const struct op_desc *prereq)
{
struct depend *dep;
- unsigned int needs_start, sat_start;
/* We don't depend on ourselves. */
- if (needs_file == satisfies_file) {
- assert(satisfies_opnum < needs_opnum);
+ if (needs->file == prereq->file) {
+ assert(prereq->op_num < needs->op_num);
return;
}
#if DEBUG_DEPS
printf("%s:%u: depends on %s:%u\n",
- filename[needs_file], needs_opnum+1,
- filename[satisfies_file], satisfies_opnum+1);
-#endif
-
- needs_start = op[needs_file][needs_opnum].group_start;
- sat_start = op[satisfies_file][satisfies_opnum].group_start;
-
- /* If needs is in a transaction, we need it before start. */
- if (needs_start) {
- switch (op[needs_file][needs_start].op) {
- case OP_TDB_TRANSACTION_START:
- needs_opnum = needs_start;
-#ifdef DEBUG_DEPS
- printf(" -> Back to %u\n", needs_start+1);
- fflush(stdout);
-#endif
- break;
- default:
- break;
- }
- }
-
- /* If satisfies is in a transaction, we wait until after commit. */
- /* FIXME: If transaction is cancelled, don't need dependency. */
- if (sat_start) {
- if (op[satisfies_file][sat_start].op
- == OP_TDB_TRANSACTION_START) {
- satisfies_opnum = sat_start
- + op[satisfies_file][sat_start].group_len;
-#ifdef DEBUG_DEPS
- printf(" -> Depends on %u\n", satisfies_opnum+1);
- fflush(stdout);
+ filename[needs->file], needs->op_num+1,
+ filename[prereq->file], prereq->op_num+1);
#endif
- }
- }
-
- assert(op[needs_file][needs_opnum].op != OP_TDB_TRAVERSE);
- assert(op[satisfies_file][satisfies_opnum].op != OP_TDB_TRAVERSE);
dep = talloc(ctx, struct depend);
- dep->needs_file = needs_file;
- dep->needs_opnum = needs_opnum;
- dep->satisfies_file = satisfies_file;
- dep->satisfies_opnum = satisfies_opnum;
- list_add(&op[satisfies_file][satisfies_opnum].post, &dep->post_list);
- list_add(&op[needs_file][needs_opnum].pre, &dep->pre_list);
- talloc_set_destructor(dep, destroy_depend);
-}
+ dep->needs = *needs;
+ dep->prereq = *prereq;
#if TRAVERSALS_TAKE_TRANSACTION_LOCK
-struct traverse_dep {
- unsigned int file;
- unsigned int op_num;
-};
-
-/* Traversals can deadlock against each other, and transactions. Force
- * order. */
-static void make_traverse_depends(char *filename[],
- struct op *op[], unsigned int num_ops[],
- unsigned int num)
-{
- unsigned int i, j, num_traversals = 0;
- struct traverse_dep *dep;
-
- /* Sort by which one runs first. */
- int compare_traverse_dep(const void *_a, const void *_b)
- {
- const struct traverse_dep *ta = _a, *tb = _b;
- const struct op *a = &op[ta->file][ta->op_num],
- *b = &op[tb->file][tb->op_num];
-
- if (a->serial != b->serial)
- return a->serial - b->serial;
-
- /* If they have same serial, it means one didn't make any
- * changes. Thus sort by end in that case. */
- return a[a->group_len].serial - b[b->group_len].serial;
+ /* If something in a traverse depends on something in another
+ * traverse/transaction, it creates a dependency between the
+ * two groups. */
+ if ((in_traverse(op[prereq->file], prereq->op_num)
+ && (starts_transaction(&op[needs->file][needs->op_num])
+ || starts_traverse(&op[needs->file][needs->op_num])))
+ || (in_traverse(op[needs->file], needs->op_num)
+ && (starts_transaction(&op[prereq->file][prereq->op_num])
+ || starts_traverse(&op[prereq->file][prereq->op_num])))) {
+ unsigned int start;
+
+ /* We are satisfied by end of group. */
+ start = op[prereq->file][prereq->op_num].group_start;
+ dep->prereq.op_num = start + op[prereq->file][start].group_len;
+ /* And we need that done by start of our group. */
+ dep->needs.op_num = op[needs->file][needs->op_num].group_start;
}
- dep = talloc_array(NULL, struct traverse_dep, 1);
-
- /* Count them. */
- for (i = 0; i < num; i++) {
- for (j = 1; j < num_ops[i]; j++) {
- /* Transaction or traverse start. */
- if (op[i][j].group_start == j) {
- dep = talloc_realloc(NULL, dep,
- struct traverse_dep,
- num_traversals+1);
- dep[num_traversals].file = i;
- dep[num_traversals].op_num = j;
- num_traversals++;
- }
+ /* There is also this case:
+ * <traverse> <read foo> ...
+ * <transaction> ... </transaction> <create foo>
+ * Where if we start the traverse then wait, we could block
+ * the transaction and deadlock.
+ *
+ * We try to address this by ensuring that where seqnum indicates it's
+ * possible, we wait for <create foo> before *starting* traverse.
+ */
+ else if (in_traverse(op[needs->file], needs->op_num)) {
+ struct op *need = &op[needs->file][needs->op_num];
+ if (op[needs->file][need->group_start].seqnum >
+ op[prereq->file][prereq->op_num].seqnum) {
+ dep->needs.op_num = need->group_start;
}
}
- qsort(dep, num_traversals, sizeof(dep[0]), compare_traverse_dep);
- for (i = 1; i < num_traversals; i++) {
- /* i depends on end of traverse i-1. */
- add_dependency(NULL, op, filename, dep[i].file, dep[i].op_num,
- dep[i-1].file, dep[i-1].op_num
- + op[dep[i-1].file][dep[i-1].op_num].group_len);
- }
- talloc_free(dep);
+#endif
+
+ /* If you depend on a transaction or chainlock, you actually
+ * depend on it ending. */
+ if (starts_transaction(&op[prereq->file][dep->prereq.op_num])
+ || starts_chainlock(&op[prereq->file][dep->prereq.op_num])) {
+ dep->prereq.op_num
+ += op[dep->prereq.file][dep->prereq.op_num].group_len;
+#if DEBUG_DEPS
+ printf("-> Actually end of transaction %s:%u\n",
+ filename[dep->prereq->file], dep->prereq->op_num+1);
+#endif
+ } else
+ /* We should never create a dependency from middle of
+ * a transaction. */
+ assert(!in_transaction(op[prereq->file], dep->prereq.op_num)
+ || op[prereq->file][dep->prereq.op_num].type
+ == OP_TDB_TRANSACTION_COMMIT
+ || op[prereq->file][dep->prereq.op_num].type
+ == OP_TDB_TRANSACTION_CANCEL);
+
+ list_add(&op[dep->prereq.file][dep->prereq.op_num].post,
+ &dep->post_list);
+ list_add(&op[dep->needs.file][dep->needs.op_num].pre,
+ &dep->pre_list);
+ talloc_set_destructor(dep, destroy_depend);
}
-#endif /* TRAVERSALS_TAKE_TRANSACTION_LOCK */
-static bool changes_db(const struct op *op)
+static bool changes_db(const TDB_DATA *key, const struct op *op)
{
- return gives(op, NULL) != NULL;
+ return gives(key, NULL, op) != NULL;
}
static void depend_on_previous(struct op *op[],
char *filename[],
unsigned int num,
- struct key_user user[],
+ struct op_desc user[],
unsigned int i,
int prev)
{
if (prev == i - 1) {
/* Just depend on previous. */
- add_dependency(NULL, op, filename,
- user[i].file, user[i].op_num,
- user[prev].file, user[prev].op_num);
+ add_dependency(NULL, op, filename, &user[i], &user[prev]);
return;
}
deps[user[i].file] = true;
for (j = i - 1; j > prev; j--) {
if (!deps[user[j].file]) {
- add_dependency(NULL, op, filename,
- user[i].file, user[i].op_num,
- user[j].file, user[j].op_num);
+ add_dependency(NULL, op, filename, &user[i], &user[j]);
deps[user[j].file] = true;
}
}
memset(prev, 0, sizeof(prev));
list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
- if (!prev[dep->satisfies_file]) {
- prev[dep->satisfies_file] = dep;
+ if (!prev[dep->prereq.file]) {
+ prev[dep->prereq.file] = dep;
continue;
}
- if (prev[dep->satisfies_file]->satisfies_opnum
- < dep->satisfies_opnum) {
- talloc_free(prev[dep->satisfies_file]);
- prev[dep->satisfies_file] = dep;
+ if (prev[dep->prereq.file]->prereq.op_num
+ < dep->prereq.op_num) {
+ talloc_free(prev[dep->prereq.file]);
+ prev[dep->prereq.file] = dep;
} else
talloc_free(dep);
}
struct depend *dep, *next;
list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
- if (deps[dep->satisfies_file]
- >= (int)dep->satisfies_opnum)
+ if (deps[dep->prereq.file]
+ >= (int)dep->prereq.op_num)
talloc_free(dep);
else
- deps[dep->satisfies_file]
- = dep->satisfies_opnum;
+ deps[dep->prereq.file]
+ = dep->prereq.op_num;
+ }
+ }
+ }
+}
+
+#if TRAVERSALS_TAKE_TRANSACTION_LOCK
+/* Force an order among the traversals, so they don't deadlock (as much) */
+static void make_traverse_depends(char *filename[],
+ struct op *op[], unsigned int num_ops[],
+ unsigned int num)
+{
+ unsigned int i, num_traversals = 0;
+ int j;
+ struct op_desc *desc;
+
+ /* Sort by which one runs first. */
+ int compare_traverse_desc(const void *_a, const void *_b)
+ {
+ const struct op_desc *da = _a, *db = _b;
+ const struct op *a = &op[da->file][da->op_num],
+ *b = &op[db->file][db->op_num];
+
+ if (a->seqnum != b->seqnum)
+ return a->seqnum - b->seqnum;
+
+ /* If they have same seqnum, it means one didn't make any
+ * changes. Thus sort by end in that case. */
+ return a[a->group_len].seqnum - b[b->group_len].seqnum;
+ }
+
+ desc = talloc_array(NULL, struct op_desc, 1);
+
+ /* Count them. */
+ for (i = 0; i < num; i++) {
+ for (j = 1; j < num_ops[i]; j++) {
+ /* Traverse start (ignore those in
+ * transactions; they're already covered by
+ * transaction dependencies). */
+ if (starts_traverse(&op[i][j])
+ && !in_transaction(op[i], j)) {
+ desc = talloc_realloc(NULL, desc,
+ struct op_desc,
+ num_traversals+1);
+ desc[num_traversals].file = i;
+ desc[num_traversals].op_num = j;
+ num_traversals++;
+ }
+ }
+ }
+ qsort(desc, num_traversals, sizeof(desc[0]), compare_traverse_desc);
+
+ for (i = 1; i < num_traversals; i++) {
+ const struct op *prev = &op[desc[i-1].file][desc[i-1].op_num];
+ const struct op *curr = &op[desc[i].file][desc[i].op_num];
+
+ /* Read traverses don't depend on each other (read lock). */
+ if (prev->type == OP_TDB_TRAVERSE_READ_START
+ && curr->type == OP_TDB_TRAVERSE_READ_START)
+ continue;
+
+ /* Only make dependency if it's clear. */
+ if (compare_traverse_desc(&desc[i], &desc[i-1])) {
+ /* i depends on end of traverse i-1. */
+ struct op_desc end = desc[i-1];
+ end.op_num += prev->group_len;
+ add_dependency(NULL, op, filename, &desc[i], &end);
+ }
+ }
+ talloc_free(desc);
+}
+
+static void set_nonblock(int fd)
+{
+ if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL)|O_NONBLOCK) != 0)
+ err(1, "Setting pipe nonblocking");
+}
+
+static bool handle_backoff(struct op *op[], int fd)
+{
+ struct op_desc desc;
+ bool handled = false;
+
+ /* Sloppy coding: we assume PIPEBUF never fills. */
+ while (read(fd, &desc, sizeof(desc)) != -1) {
+ unsigned int i;
+ handled = true;
+ for (i = desc.op_num; i > 0; i--) {
+ if (op[desc.file][i].type == OP_TDB_TRAVERSE) {
+ /* We insert a fake end here. */
+ op[desc.file][i].type
+ = OP_TDB_TRAVERSE_END_EARLY;
+ break;
+ } else if (starts_traverse(&op[desc.file][i])) {
+ unsigned int start = i;
+ struct op tmp = op[desc.file][i];
+ /* Move the ops outside traverse. */
+ memmove(&op[desc.file][i],
+ &op[desc.file][i+1],
+ (desc.op_num-i-1) * sizeof(op[0][0]));
+ op[desc.file][desc.op_num] = tmp;
+ while (op[desc.file][i].group_start == start) {
+ op[desc.file][i++].group_start
+ = desc.op_num;
+ }
+ break;
}
}
}
+ return handled;
+}
+
+#else /* !TRAVERSALS_TAKE_TRANSACTION_LOCK */
+static bool handle_backoff(struct op *op[], int fd)
+{
+ return false;
}
+#endif
static void derive_dependencies(char *filename[],
struct op *op[], unsigned int num_ops[],
/* Create hash table for faster key lookup. */
hash = hash_ops(op, num_ops, num);
- /* Sort them by serial number. */
+ /* Sort them by sequence number. */
sort_ops(hash, filename, op, num);
/* Create dependencies back to the last change, rather than
continue;
for (i = 0; i < hash[h].num_users; i++) {
- if (changes_db(&op[hash[h].user[i].file]
+ if (changes_db(&hash[h].key, &op[hash[h].user[i].file]
[hash[h].user[i].op_num])) {
depend_on_previous(op, filename, num,
hash[h].user, i, prev);
prev = i;
} else if (prev >= 0)
add_dependency(hash, op, filename,
- hash[h].user[i].file,
- hash[h].user[i].op_num,
- hash[h].user[prev].file,
- hash[h].user[prev].op_num);
+ &hash[h].user[i],
+ &hash[h].user[prev]);
}
}
optimize_dependencies(op, num_ops, num);
}
-int main(int argc, char *argv[])
+static struct timeval run_test(char *argv[],
+ unsigned int num_ops[],
+ unsigned int hashsize[],
+ unsigned int tdb_flags[],
+ unsigned int open_flags[],
+ struct op *op[],
+ int fds[2])
{
- struct timeval start, end;
- unsigned int i, num_ops[argc], hashsize[argc], tdb_flags[argc], open_flags[argc];
- struct op *op[argc];
- int fds[2];
- char c;
+ unsigned int i;
+ struct timeval start, end, diff;
bool ok = true;
- if (argc < 3)
- errx(1, "Usage: %s <tdbfile> <tracefile>...", argv[0]);
-
- pipes = talloc_array(NULL, struct pipe, argc - 2);
- for (i = 0; i < argc - 2; i++) {
- printf("Loading tracefile %s...", argv[2+i]);
- fflush(stdout);
- op[i] = load_tracefile(argv[2+i], &num_ops[i], &hashsize[i],
- &tdb_flags[i], &open_flags[i]);
- if (pipe(pipes[i].fd) != 0)
- err(1, "creating pipe");
- printf("done\n");
- }
-
- printf("Calculating inter-dependencies...");
- fflush(stdout);
- derive_dependencies(argv+2, op, num_ops, i);
- printf("done\n");
-
- /* Don't fork for single arg case: simple debugging. */
- if (argc == 3) {
- struct tdb_context *tdb;
- tdb = tdb_open_ex(argv[1], hashsize[0], tdb_flags[0],
- open_flags[0], 0600,
- NULL, hash_key);
- printf("Single threaded run...");
- fflush(stdout);
-
- run_ops(tdb, pipes[0].fd[0], argv+2, op, 0, 1, num_ops[0]);
- check_deps(argv[2], op[0], num_ops[0]);
-
- printf("done\n");
- exit(0);
- }
-
- if (pipe(fds) != 0)
- err(1, "creating pipe");
-
- for (i = 0; i < argc - 2; i++) {
+ for (i = 0; argv[i+2]; i++) {
struct tdb_context *tdb;
+ char c;
switch (fork()) {
case -1:
err(1, "fork failed");
case 0:
close(fds[1]);
- tdb = tdb_open_ex(argv[1], hashsize[i], tdb_flags[i],
- open_flags[i], 0600,
- NULL, hash_key);
+ tdb = tdb_open_ex(argv[1], hashsize[i],
+ tdb_flags[i]|TDB_NOSYNC,
+ open_flags[i], 0600, NULL, hash_key);
if (!tdb)
err(1, "Opening tdb %s", argv[1]);
if (read(fds[0], &c, 1) != 1)
exit(1);
run_ops(tdb, pipes[i].fd[0], argv+2, op, i, 1,
- num_ops[i]);
+ num_ops[i], false);
check_deps(argv[2+i], op[i], num_ops[i]);
exit(0);
default:
if (write(fds[1], hashsize, i) != i)
err(1, "Writing to wakeup pipe");
- for (i = 0; i < argc - 2; i++) {
+ for (i = 0; argv[i + 2]; i++) {
int status;
wait(&status);
if (!WIFEXITED(status)) {
gettimeofday(&end, NULL);
printf("done\n");
- end.tv_sec -= start.tv_sec;
+ if (end.tv_usec < start.tv_usec) {
+ end.tv_usec += 1000000;
+ end.tv_sec--;
+ }
+ diff.tv_sec = end.tv_sec - start.tv_sec;
+ diff.tv_usec = end.tv_usec - start.tv_usec;
+ return diff;
+}
+
+int main(int argc, char *argv[])
+{
+ struct timeval diff;
+ unsigned int i, num_ops[argc], hashsize[argc], tdb_flags[argc], open_flags[argc];
+ struct op *op[argc];
+ int fds[2];
+
+ if (argc < 3)
+ errx(1, "Usage: %s <tdbfile> <tracefile>...", argv[0]);
+
+ pipes = talloc_array(NULL, struct pipe, argc - 1);
+ for (i = 0; i < argc - 2; i++) {
+ printf("Loading tracefile %s...", argv[2+i]);
+ fflush(stdout);
+ op[i] = load_tracefile(argv[2+i], &num_ops[i], &hashsize[i],
+ &tdb_flags[i], &open_flags[i]);
+ if (pipe(pipes[i].fd) != 0)
+ err(1, "creating pipe");
+ printf("done\n");
+ }
+
+ printf("Calculating inter-dependencies...");
+ fflush(stdout);
+ derive_dependencies(argv+2, op, num_ops, i);
+ printf("done\n");
+
+ /* Don't fork for single arg case: simple debugging. */
+ if (argc == 3) {
+ struct tdb_context *tdb;
+ tdb = tdb_open_ex(argv[1], hashsize[0], tdb_flags[0]|TDB_NOSYNC,
+ open_flags[0], 0600, NULL, hash_key);
+ printf("Single threaded run...");
+ fflush(stdout);
+
+ run_ops(tdb, pipes[0].fd[0], argv+2, op, 0, 1, num_ops[0],
+ false);
+ check_deps(argv[2], op[0], num_ops[0]);
+
+ printf("done\n");
+ exit(0);
+ }
+
+ if (pipe(fds) != 0)
+ err(1, "creating pipe");
+
+#if TRAVERSALS_TAKE_TRANSACTION_LOCK
+ if (pipe(pipes[argc-2].fd) != 0)
+ err(1, "creating pipe");
+ backoff_fd = pipes[argc-2].fd[1];
+ set_nonblock(pipes[argc-2].fd[1]);
+ set_nonblock(pipes[argc-2].fd[0]);
+#endif
+
+ do {
+ diff = run_test(argv, num_ops, hashsize, tdb_flags, open_flags,
+ op, fds);
+ } while (handle_backoff(op, pipes[argc-2].fd[0]));
+
printf("Time replaying: %lu usec\n",
- end.tv_sec * 1000000UL + (end.tv_usec - start.tv_usec));
+ diff.tv_sec * 1000000UL + diff.tv_usec);
exit(0);
}
projects / ccan / blobdiff