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[PATCH v7 40/42] refs.c: pass a skip list to name_conflict_fn

From
Ronnie Sahlberg <sahlberg@google.com>
Date
May 14, 2014, 21:17 UTC
Message-ID
<1400102236-30082-41-git-send-email-sahlberg@google.com>
In-Reply-To
<1400102236-30082-1-git-send-email-sahlberg@google.com>

Allow passing a list of refs to skip checking to name_conflict_fn. There are some conditions where we want to allow a temporary conflict and skip checking those refs. For example if we have a transaction that 1, guarantees that m is a packed refs and there is no loose ref for m 2, the transaction will delete m from the packed ref 3, the transaction will create conflicting m/m

For this case we want to be able to lock and create m/m since we know that the conflict is only transient. I.e. the conflict will be automatically resolved by the transaction when it deletes m.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 refs.c | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)
diff --git a/refs.c b/refs.c
index 6b8b7fe..7569f4e 100644
--- a/refs.c
+++ b/refs.c
@@ -798,11 +798,19 @@ struct name_conflict_cb {
 	const char *refname;
 	const char *oldrefname;
 	const char *conflicting_refname;
+	const char **skip;
+	int skipnum;
 };
 
 static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
 {
 	struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
+	int i;
+	for(i = 0; i < data->skipnum; i++) {
+		if (!strcmp(entry->name, data->skip[i])) {
+			return 0;
+		}
+	}
 	if (data->oldrefname && !strcmp(data->oldrefname, entry->name))
 		return 0;
 	if (names_conflict(data->refname, entry->name)) {
@@ -817,15 +825,21 @@ static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
  * conflicting with the name of an existing reference in dir.  If
  * oldrefname is non-NULL, ignore potential conflicts with oldrefname
  * (e.g., because oldrefname is scheduled for deletion in the same
- * operation).
+ * operation). skip contains a list of refs we want to skip checking for
+ * conflicts with. Refs may be skipped due to us knowing that it will
+ * be deleted later during a transaction that deletes one reference and then
+ * creates a new conflicting reference. For example a rename from m to m/m.
  */
 static int is_refname_available(const char *refname, const char *oldrefname,
-				struct ref_dir *dir)
+				struct ref_dir *dir,
+				const char **skip, int skipnum)
 {
 	struct name_conflict_cb data;
 	data.refname = refname;
 	data.oldrefname = oldrefname;
 	data.conflicting_refname = NULL;
+	data.skip = skip;
+	data.skipnum = skipnum;
 
 	sort_ref_dir(dir);
 	if (do_for_each_entry_in_dir(dir, 0, name_conflict_fn, &data)) {
@@ -2037,7 +2051,8 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
-					    int flags, int *type_p)
+					    int flags, int *type_p,
+					    const char **skip, int skipnum)
 {
 	char *ref_file;
 	const char *orig_refname = refname;
@@ -2084,7 +2099,9 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	 * name is a proper prefix of our refname.
 	 */
 	if (missing &&
-	     !is_refname_available(refname, NULL, get_packed_refs(&ref_cache))) {
+	     !is_refname_available(refname, NULL,
+				   get_packed_refs(&ref_cache),
+				   skip, skipnum)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
@@ -2142,7 +2159,7 @@ struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
 {
-	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p);
+	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p, NULL, 0);
 }
 
 /*
@@ -2581,6 +2598,9 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
 	const char *symref = NULL;
 
+	if (!strcmp(oldrefname, newrefname))
+		return 0;
+
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
@@ -2591,10 +2611,12 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	if (!symref)
 		return error("refname %s not found", oldrefname);
 
-	if (!is_refname_available(newrefname, oldrefname, get_packed_refs(&ref_cache)))
+	if (!is_refname_available(newrefname, oldrefname,
+				  get_packed_refs(&ref_cache), NULL, 0))
 		return 1;
 
-	if (!is_refname_available(newrefname, oldrefname, get_loose_refs(&ref_cache)))
+	if (!is_refname_available(newrefname, oldrefname,
+				  get_loose_refs(&ref_cache), NULL, 0))
 		return 1;
 
 	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
@@ -2627,7 +2649,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 
 	logmoved = log;
 
-	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL, NULL, 0);
 	if (!lock) {
 		error("unable to lock %s for update", newrefname);
 		goto rollback;
@@ -2642,7 +2664,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	return 0;
 
  rollback:
-	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL, NULL, 0);
 	if (!lock) {
 		error("unable to lock %s for rollback", oldrefname);
 		goto rollbacklog;
@@ -3501,7 +3523,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 						    update->old_sha1 :
 						    NULL),
 						   update->flags,
-						   &update->type);
+						   &update->type,
+						   delnames, delnum);
 		if (!update->lock) {
 			if (err)
 				strbuf_addf(err, "Cannot lock the ref '%s'.",

-- 
2.0.0.rc3.471.g2055d11.dirty
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 41 of 43 in “Use ref transactions for all ref updates”
  1. 00/42 Use ref transactions for all ref updatesRonnie Sahlberg, May 14, 2014
  2. 01/42 refs.c: constify the sha arguments for ref_transaction_create|delete|updateRonnie Sahlberg, May 14, 2014
  3. 02/42 refs.c: allow passing NULL to ref_transaction_freeRonnie Sahlberg, May 14, 2014
  4. 03/42 refs.c: add a strbuf argument to ref_transaction_commit for error loggingRonnie Sahlberg, May 14, 2014
  5. 04/42 refs.c: make ref_update_reject_duplicates take a strbuf argument for errorsRonnie Sahlberg, May 14, 2014
  6. 05/42 update-ref.c: log transaction error from the update_refRonnie Sahlberg, May 14, 2014
  7. 06/42 refs.c: make update_ref_write update a strbuf on failureRonnie Sahlberg, May 14, 2014
  8. 07/42 refs.c: remove the onerr argument to ref_transaction_commitRonnie Sahlberg, May 14, 2014
  9. 08/42 refs.c: change ref_transaction_update() to do error checking and return statusRonnie Sahlberg, May 14, 2014
  10. 09/42 refs.c: change ref_transaction_create to do error checking and return statusRonnie Sahlberg, May 14, 2014
  11. 10/42 refs.c: ref_transaction_delete to check for error and return statusRonnie Sahlberg, May 14, 2014
  12. 11/42 tag.c: use ref transactions when doing updatesRonnie Sahlberg, May 14, 2014
  13. 12/42 replace.c: use the ref transaction functions for updatesRonnie Sahlberg, May 14, 2014
  14. 13/42 commit.c: use ref transactions for updatesRonnie Sahlberg, May 14, 2014
  15. 14/42 sequencer.c: use ref transactions for all ref updatesRonnie Sahlberg, May 14, 2014
  16. 15/42 fast-import.c: change update_branch to use ref transactionsRonnie Sahlberg, May 14, 2014
  17. 16/42 branch.c: use ref transaction for all ref updatesRonnie Sahlberg, May 14, 2014
  18. 17/42 refs.c: change update_ref to use a transactionRonnie Sahlberg, May 14, 2014
  19. 18/42 refs.c: free the transaction before returning when number of updates is 0Ronnie Sahlberg, May 14, 2014
  20. 19/42 refs.c: ref_transaction_commit should not free the transactionRonnie Sahlberg, May 14, 2014
  21. 20/42 fetch.c: clear errno before calling functions that might set itRonnie Sahlberg, May 14, 2014
  22. 21/42 fetch.c: change s_update_ref to use a ref transactionRonnie Sahlberg, May 14, 2014
  23. 22/42 fetch.c: use a single ref transaction for all ref updatesRonnie Sahlberg, May 14, 2014
  24. 23/42 receive-pack.c: use a reference transaction for updating the refsRonnie Sahlberg, May 14, 2014
  25. 24/42 fast-import.c: use a ref transaction when dumping tagsRonnie Sahlberg, May 14, 2014
  26. 25/42 walker.c: use ref transaction for ref updatesRonnie Sahlberg, May 14, 2014
  27. 26/42 refs.c: make write_ref_sha1 staticRonnie Sahlberg, May 14, 2014
  28. 27/42 refs.c: make lock_ref_sha1 staticRonnie Sahlberg, May 14, 2014
  29. 28/42 refs.c: add transaction.status and track OPEN/CLOSED/ERRORRonnie Sahlberg, May 14, 2014
  30. 29/42 refs.c: remove the update_ref_lock functionRonnie Sahlberg, May 14, 2014
  31. 30/42 refs.c: remove the update_ref_write functionRonnie Sahlberg, May 14, 2014
  32. 31/42 refs.c: remove lock_ref_sha1Ronnie Sahlberg, May 14, 2014
  33. 32/42 refs.c: make prune_ref use a transaction to delete the refRonnie Sahlberg, May 14, 2014
  34. 33/42 refs.c: make delete_ref use a transactionRonnie Sahlberg, May 14, 2014
  35. 34/42 refs.c: pass the ref log message to _create/delete/update instead of _commitRonnie Sahlberg, May 14, 2014
  36. 35/42 refs.c: pass NULL as *flags to read_ref_fullRonnie Sahlberg, May 14, 2014
  37. 36/42 refs.c: pack all refs before we start to rename a refRonnie Sahlberg, May 14, 2014
  38. 37/42 refs.c: move the check for valid refname to lock_ref_sha1_basicRonnie Sahlberg, May 14, 2014
  39. 38/42 refs.c: call lock_ref_sha1_basic directly from commitRonnie Sahlberg, May 14, 2014
  40. 39/42 refs.c: add a new flag for transaction delete for refs we know are packed onlyRonnie Sahlberg, May 14, 2014
  41. 40/42 refs.c: pass a skip list to name_conflict_fnRonnie Sahlberg, May 14, 2014
  42. 41/42 refs.c: make rename_ref use a transactionRonnie Sahlberg, May 14, 2014
  43. 42/42 refs.c: remove forward declaration of write_ref_sha1Ronnie Sahlberg, May 14, 2014

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