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Re: [PATCH v4 15/27] fast-import.c: change update_branch to use ref transactions

From
Ronnie Sahlberg <sahlberg@google.com>
Date
Apr 29, 2014, 16:57 UTC
Message-ID
<CAL=YDWkD+0=Cy5wjAUtVn8QNtVr3NSaUkRoEnC+QcdRhYG59vA@mail.gmail.com>
In-Reply-To
<CAPig+cTE9+XHYfnynMykbYf=0kMivj5wFu0Lovnr8XbxyEpsyA@mail.gmail.com>
On Mon, Apr 28, 2014 at 7:18 PM, Eric Sunshine <sunshine@sunshineco.com> wrote:
Show 61 quoted lines
> On Mon, Apr 28, 2014 at 6:54 PM, Ronnie Sahlberg <sahlberg@google.com> wrote:
>> Change update_branch() to use ref transactions for updates.
>>
>> Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
>> ---
>>  fast-import.c | 20 ++++++++++++--------
>>  1 file changed, 12 insertions(+), 8 deletions(-)
>>
>> diff --git a/fast-import.c b/fast-import.c
>> index fb4738d..300c8dc 100644
>> --- a/fast-import.c
>> +++ b/fast-import.c
>> @@ -1678,36 +1678,40 @@ found_entry:
>>  static int update_branch(struct branch *b)
>>  {
>>         static const char *msg = "fast-import";
>> -       struct ref_lock *lock;
>> +       struct ref_transaction *transaction;
>>         unsigned char old_sha1[20];
>> +       struct strbuf err = STRBUF_INIT;
>>
>>         if (is_null_sha1(b->sha1))
>>                 return 0;
>>         if (read_ref(b->name, old_sha1))
>>                 hashclr(old_sha1);
>> -       lock = lock_any_ref_for_update(b->name, old_sha1, 0, NULL);
>> -       if (!lock)
>> -               return error("Unable to lock %s", b->name);
>>         if (!force_update && !is_null_sha1(old_sha1)) {
>>                 struct commit *old_cmit, *new_cmit;
>>
>>                 old_cmit = lookup_commit_reference_gently(old_sha1, 0);
>>                 new_cmit = lookup_commit_reference_gently(b->sha1, 0);
>>                 if (!old_cmit || !new_cmit) {
>> -                       unlock_ref(lock);
>>                         return error("Branch %s is missing commits.", b->name);
>>                 }
>>
>>                 if (!in_merge_bases(old_cmit, new_cmit)) {
>> -                       unlock_ref(lock);
>>                         warning("Not updating %s"
>>                                 " (new tip %s does not contain %s)",
>>                                 b->name, sha1_to_hex(b->sha1), sha1_to_hex(old_sha1));
>>                         return -1;
>>                 }
>>         }
>> -       if (write_ref_sha1(lock, b->sha1, msg) < 0)
>> -               return error("Unable to update %s", b->name);
>> +       transaction = ref_transaction_begin();
>> +       if ((!transaction ||
>> +           ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
>> +                                  0, 1)) ||
>> +           (ref_transaction_commit(transaction, msg, &err) &&
>> +            !(transaction = NULL))) {
>> +               ref_transaction_rollback(transaction);
>> +               return error("Unable to update branch %s: %s", b->name,
>> +                            strbuf_detach(&err, NULL));
>
> Iffy strbuf handling. The strbuf content is being leaked here whether
> detached or not.
>
Thanks!

I have updated this and all other patches to make sure we do a strbuf_release() any time we have added to the string.

I also did a quick audit of the strbuf_detach() use in builtin/* (which I based my use on) and there seems to be quite common that strbuf_detach() is used in a way that will leak memory.

I will make a note and perhaps audit all the other strbuf_detach() calls for a future patch series.

Show 6 quoted lines
>> +       }
>>         return 0;
>>  }
>>
>> --
>> 1.9.1.528.g98b8868.dirty
Previous: Eric SunshineNext: Junio C Hamano
Message 23 of 38 in “Use ref transactions for all ref updates”
  1. 00/27 Use ref transactions for all ref updatesRonnie Sahlberg, Apr 28, 2014
  2. 01/27 refs.c: constify the sha arguments for ref_transaction_create|delete|updateRonnie Sahlberg, Apr 28, 2014
  3. 02/27 refs.c: allow passing NULL to ref_transaction_freeRonnie Sahlberg, Apr 28, 2014
  4. 03/27 refs.c: add a strbuf argument to ref_transaction_commit for error loggingRonnie Sahlberg, Apr 28, 2014
  5. 04/27 refs.c: make ref_update_reject_duplicates take a strbuf argument for errorsRonnie Sahlberg, Apr 28, 2014
  6. 05/27 update-ref.c: log transaction error from the update_refRonnie Sahlberg, Apr 28, 2014
  7. 06/27 refs.c: make update_ref_write update a strbuf on failureRonnie Sahlberg, Apr 28, 2014
  8. 07/27 refs.c: remove the onerr argument to ref_transaction_commitRonnie Sahlberg, Apr 28, 2014
  9. 08/27 refs.c: change ref_transaction_update() to do error checking and return statusRonnie Sahlberg, Apr 28, 2014
  10. Eric SunshineApr 29, 2014
  11. Ronnie SahlbergApr 29, 2014
  12. 09/27 refs.c: change ref_transaction_create to do error checking and return statusRonnie Sahlberg, Apr 28, 2014
  13. 10/27 refs.c: ref_transaction_delete to check for error and return statusRonnie Sahlberg, Apr 28, 2014
  14. 11/27 tag.c: use ref transactions when doing updatesRonnie Sahlberg, Apr 28, 2014
  15. 12/27 replace.c: use the ref transaction functions for updatesRonnie Sahlberg, Apr 28, 2014
  16. Eric SunshineApr 29, 2014
  17. Ronnie SahlbergApr 29, 2014
  18. Eric SunshineApr 29, 2014
  19. 13/27 commit.c: use ref transactions for updatesRonnie Sahlberg, Apr 28, 2014
  20. 14/27 sequencer.c: use ref transactions for all ref updatesRonnie Sahlberg, Apr 28, 2014
  21. 15/27 fast-import.c: change update_branch to use ref transactionsRonnie Sahlberg, Apr 28, 2014
  22. Eric SunshineApr 29, 2014
  23. Ronnie SahlbergApr 29, 2014
  24. Junio C HamanoApr 29, 2014
  25. 16/27 branch.c: use ref transaction for all ref updatesRonnie Sahlberg, Apr 28, 2014
  26. 17/27 refs.c: change update_ref to use a transactionRonnie Sahlberg, Apr 28, 2014
  27. 18/27 refs.c: free the transaction before returning when number of updates is 0Ronnie Sahlberg, Apr 28, 2014
  28. 19/27 refs.c: ref_transaction_commit should not free the transactionRonnie Sahlberg, Apr 28, 2014
  29. 20/27 fetch.c: clear errno before calling functions that might set itRonnie Sahlberg, Apr 28, 2014
  30. 21/27 fetch.c: change s_update_ref to use a ref transactionRonnie Sahlberg, Apr 28, 2014
  31. 22/27 fetch.c: use a single ref transaction for all ref updatesRonnie Sahlberg, Apr 28, 2014
  32. 23/27 receive-pack.c: use a reference transaction for updating the refsRonnie Sahlberg, Apr 28, 2014
  33. 24/27 fast-import.c: use a ref transaction when dumping tagsRonnie Sahlberg, Apr 28, 2014
  34. 25/27 walker.c: use ref transaction for ref updatesRonnie Sahlberg, Apr 28, 2014
  35. 26/27 refs.c: make write_ref_sha1 staticRonnie Sahlberg, Apr 28, 2014
  36. 27/27 refs.c: make lock_ref_sha1 staticRonnie Sahlberg, Apr 28, 2014
  37. Junio C HamanoApr 29, 2014
  38. Ronnie SahlbergApr 29, 2014

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