s3:locking: add brl_req_guid() and brl_req_mem_ctx() helper functions

This allows the vfs backend to detect a retry and keep state between
the retries.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14113

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
(cherry picked from commit 66d92f37c3a643d97489a59bb6d1e75e91528c20)

3 files changed, 59 insertions, 5 deletions

diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 0a85bd0b057..f22580164f9 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -46,6 +46,8 @@ static struct db_context *brlock_db;
 
 struct byte_range_lock {
 	struct files_struct *fsp;
+	TALLOC_CTX *req_mem_ctx;
+	const struct GUID *req_guid;
 	unsigned int num_locks;
 	bool modified;
 	struct lock_struct *lock_data;
@@ -84,6 +86,25 @@ struct files_struct *brl_fsp(struct byte_range_lock *brl)
 	return brl->fsp;
 }
 
+TALLOC_CTX *brl_req_mem_ctx(const struct byte_range_lock *brl)
+{
+	if (brl->req_mem_ctx == NULL) {
+		return talloc_get_type_abort(brl, struct byte_range_lock);
+	}
+
+	return brl->req_mem_ctx;
+}
+
+const struct GUID *brl_req_guid(const struct byte_range_lock *brl)
+{
+	if (brl->req_guid == NULL) {
+		static const struct GUID brl_zero_req_guid;
+		return &brl_zero_req_guid;
+	}
+
+	return brl->req_guid;
+}
+
 /****************************************************************************
  See if two locking contexts are equal.
 ****************************************************************************/
@@ -1823,6 +1844,25 @@ struct byte_range_lock *brl_get_locks(TALLOC_CTX *mem_ctx, files_struct *fsp)
 	return br_lck;
 }
 
+struct byte_range_lock *brl_get_locks_for_locking(TALLOC_CTX *mem_ctx,
+						  files_struct *fsp,
+						  TALLOC_CTX *req_mem_ctx,
+						  const struct GUID *req_guid)
+{
+	struct byte_range_lock *br_lck = NULL;
+
+	br_lck = brl_get_locks(mem_ctx, fsp);
+	if (br_lck == NULL) {
+		return NULL;
+	}
+	SMB_ASSERT(req_mem_ctx != NULL);
+	br_lck->req_mem_ctx = req_mem_ctx;
+	SMB_ASSERT(req_guid != NULL);
+	br_lck->req_guid = req_guid;
+
+	return br_lck;
+}
+
 struct brl_get_locks_readonly_state {
 	TALLOC_CTX *mem_ctx;
 	struct byte_range_lock **br_lock;
@@ -1884,14 +1924,11 @@ struct byte_range_lock *brl_get_locks_readonly(files_struct *fsp)
 		/*
 		 * No locks on this file. Return an empty br_lock.
 		 */
-		br_lock = talloc(fsp, struct byte_range_lock);
+		br_lock = talloc_zero(fsp, struct byte_range_lock);
 		if (br_lock == NULL) {
 			return NULL;
 		}
 
-		br_lock->num_locks = 0;
-		br_lock->lock_data = NULL;
-
 	} else if (!NT_STATUS_IS_OK(status)) {
 		DEBUG(3, ("Could not parse byte range lock record: "
 			  "%s\n", nt_errstr(status)));
diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index d87a882d14f..8fa1237d6ad 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -232,6 +232,8 @@ static void decrement_current_lock_count(files_struct *fsp,
 
 struct do_lock_state {
 	struct files_struct *fsp;
+	TALLOC_CTX *req_mem_ctx;
+	const struct GUID *req_guid;
 	uint64_t smblctx;
 	uint64_t count;
 	uint64_t offset;
@@ -251,7 +253,10 @@ static void do_lock_fn(
 	struct do_lock_state *state = private_data;
 	struct byte_range_lock *br_lck = NULL;
 
-	br_lck = brl_get_locks(talloc_tos(), state->fsp);
+	br_lck = brl_get_locks_for_locking(talloc_tos(),
+					   state->fsp,
+					   state->req_mem_ctx,
+					   state->req_guid);
 	if (br_lck == NULL) {
 		state->status = NT_STATUS_NO_MEMORY;
 		return;
@@ -272,6 +277,8 @@ static void do_lock_fn(
 }
 
 NTSTATUS do_lock(files_struct *fsp,
+		 TALLOC_CTX *req_mem_ctx,
+		 const struct GUID *req_guid,
 		 uint64_t smblctx,
 		 uint64_t count,
 		 uint64_t offset,
@@ -282,6 +289,8 @@ NTSTATUS do_lock(files_struct *fsp,
 {
 	struct do_lock_state state = {
 		.fsp = fsp,
+		.req_mem_ctx = req_mem_ctx,
+		.req_guid = req_guid,
 		.smblctx = smblctx,
 		.count = count,
 		.offset = offset,
diff --git a/source3/locking/proto.h b/source3/locking/proto.h
index 7cb8bf3e3c9..7cf681561bc 100644
--- a/source3/locking/proto.h
+++ b/source3/locking/proto.h
@@ -30,6 +30,8 @@ void brl_shutdown(void);
 
 unsigned int brl_num_locks(const struct byte_range_lock *brl);
 struct files_struct *brl_fsp(struct byte_range_lock *brl);
+TALLOC_CTX *brl_req_mem_ctx(const struct byte_range_lock *brl);
+const struct GUID *brl_req_guid(const struct byte_range_lock *brl);
 
 bool byte_range_valid(uint64_t ofs, uint64_t len);
 bool byte_range_overlap(uint64_t ofs1,
@@ -76,6 +78,10 @@ int brl_forall(void (*fn)(struct file_id id, struct server_id pid,
 			  br_off start, br_off size,
 			  void *private_data),
 	       void *private_data);
+struct byte_range_lock *brl_get_locks_for_locking(TALLOC_CTX *mem_ctx,
+						  files_struct *fsp,
+						  TALLOC_CTX *req_mem_ctx,
+						  const struct GUID *req_guid);
 struct byte_range_lock *brl_get_locks(TALLOC_CTX *mem_ctx,
 					files_struct *fsp);
 struct byte_range_lock *brl_get_locks_readonly(files_struct *fsp);
@@ -100,6 +106,8 @@ NTSTATUS query_lock(files_struct *fsp,
 			enum brl_type *plock_type,
 			enum brl_flavour lock_flav);
 NTSTATUS do_lock(files_struct *fsp,
+		 TALLOC_CTX *req_mem_ctx,
+		 const struct GUID *req_guid,
 		 uint64_t smblctx,
 		 uint64_t count,
 		 uint64_t offset,