When compacting tables, we store the locks of all tables we are about to
compact in the `table_locks` array. As we currently only ever compact
all tables in the user-provided range or none, we simply track those
locks via the indices of the respective tables in the merged stack.
This is about to change though, as we will introduce a mode where auto
compaction gracefully handles the case of already-locked files. In this
case, it may happen that we only compact a subset of the user-supplied
range of tables. In this case, the indices will not necessarily match
the lock indices anymore.
Refactor the code such that we track the number of locks via a separate
variable. The resulting code is expected to perform the same, but will
make it easier to perform the described change.
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
reftable/stack.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/reftable/stack.c b/reftable/stack.c
index e5959d2c76..07e7ffc6b9 100644
--- a/reftable/stack.c
+++ b/reftable/stack.c
@@ -1016,7 +1016,7 @@ static int stack_compact_range(struct reftable_stack *st,
struct lock_file *table_locks = NULL;
struct tempfile *new_table = NULL;
int is_empty_table = 0, err = 0;
- size_t i;
+ size_t i, nlocks = 0;
if (first > last || (!expiry && first == last)) {
err = 0;
@@ -1051,7 +1051,7 @@ static int stack_compact_range(struct reftable_stack *st,
for (i = first; i <= last; i++) {
stack_filename(&table_name, st, reader_name(st->readers[i]));
- err = hold_lock_file_for_update(&table_locks[i - first],
+ err = hold_lock_file_for_update(&table_locks[nlocks],
table_name.buf, LOCK_NO_DEREF);
if (err < 0) {
if (errno == EEXIST)
@@ -1066,7 +1066,7 @@ static int stack_compact_range(struct reftable_stack *st,
* run into file descriptor exhaustion when we compress a lot
* of tables.
*/
- err = close_lock_file_gently(&table_locks[i - first]);
+ err = close_lock_file_gently(&table_locks[nlocks++]);
if (err < 0) {
err = REFTABLE_IO_ERROR;
goto done;
@@ -1183,8 +1183,8 @@ static int stack_compact_range(struct reftable_stack *st,
* Delete the old tables. They may still be in use by concurrent
* readers, so it is expected that unlinking tables may fail.
*/
- for (i = first; i <= last; i++) {
- struct lock_file *table_lock = &table_locks[i - first];
+ for (i = 0; i < nlocks; i++) {
+ struct lock_file *table_lock = &table_locks[i];
char *table_path = get_locked_file_path(table_lock);
unlink(table_path);
free(table_path);
@@ -1192,8 +1192,8 @@ static int stack_compact_range(struct reftable_stack *st,
done:
rollback_lock_file(&tables_list_lock);
- for (i = first; table_locks && i <= last; i++)
- rollback_lock_file(&table_locks[i - first]);
+ for (i = 0; table_locks && i < nlocks; i++)
+ rollback_lock_file(&table_locks[i]);
reftable_free(table_locks);
delete_tempfile(&new_table);
--
2.46.0.dirty
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