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Re: [PATCH v3 10/24] make sure partially read index is not changed

From
Eric Sunshine <sunshine@sunshineco.com>
Date
Aug 18, 2013, 21:06 UTC
Message-ID
<CAPig+cTJQrVm+r77utWzduU3KqC5WPX_b4Vbvxyjezd0Wc4LZw@mail.gmail.com>
In-Reply-To
<1376854933-31241-11-git-send-email-t.gummerer@gmail.com>
On Sun, Aug 18, 2013 at 3:41 PM, Thomas Gummerer <t.gummerer@gmail.com> wrote:
> A partially read index file currently cannot be written to disk.  Make
> sure that never happens, by erroring out when a caller tries to write a
s/,//
> partially read index.  Do the same when trying to re-read a partially
> read index without having discarded it first to avoid loosing any
s/loosing/losing/
> information.
>
> Forcing the caller to load the right part of the index file instead of
> re-reading it when changing it, gives a bit of a performance advantage,

s/it,/it/ (or s/file instead/file, instead/) s/advantage,/advantage/

> by avoiding to read parts of the index twice.
/to read/reading/
More below...
Show 25 quoted lines
>
> Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
> ---
>  read-cache.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/read-cache.c b/read-cache.c
> index 38b9a04..7a27f9b 100644
> --- a/read-cache.c
> +++ b/read-cache.c
> @@ -1332,6 +1332,8 @@ int read_index_filtered_from(struct index_state *istate, const char *path,
>         void *mmap;
>         size_t mmap_size;
>
> +       if (istate->filter_opts)
> +               die("BUG: Can't re-read partially read index");
>         errno = EBUSY;
>         if (istate->initialized)
>                 return istate->cache_nr;
> @@ -1455,6 +1457,8 @@ void update_index_if_able(struct index_state *istate, struct lock_file *lockfile
>
>  int write_index(struct index_state *istate, int newfd)
>  {
> +       if (istate->filter_opts)
> +               die("BUG: index: cannot write a partially read index");
Consistency nit:

In the preceding hunk, the error message starts "BUG: Can't...", but in this hunk we have "BUG: index: cannot...".

So, "BUG:" is the prefix of one, but "BUG: index:" is the prefix of the other.
Spelling difference: "Can't" vs. "cannot".
Capitalization difference: "Can't" vs. "cannot".
Show 6 quoted lines
>         return istate->ops->write_index(istate, newfd);
>  }
>
> --
> 1.8.3.4.1231.g9fbf354.dirty
>
Previous: Thomas GummererNext: Thomas Gummerer
Message 20 of 55 in “Index-v5”
  1. 00/24 Index-v5Thomas Gummerer, Aug 18, 2013
  2. 01/24 t2104: Don't fail for index versions other than [23]Thomas Gummerer, Aug 18, 2013
  3. 02/24 read-cache: use fixed width integer typesThomas Gummerer, Aug 18, 2013
  4. Eric SunshineAug 18, 2013
  5. Junio C HamanoAug 20, 2013
  6. Thomas GummererAug 21, 2013
  7. 03/24 read-cache: split index file version specific functionalityThomas Gummerer, Aug 18, 2013
  8. 04/24 read-cache: clear version in discard_index()Thomas Gummerer, Aug 18, 2013
  9. Junio C HamanoAug 20, 2013
  10. Thomas GummererAug 21, 2013
  11. 05/24 read-cache: move index v2 specific functions to their own fileThomas Gummerer, Aug 18, 2013
  12. 06/24 read-cache: Don't compare uid, gid and ino on cygwinThomas Gummerer, Aug 18, 2013
  13. Ramsay JonesAug 18, 2013
  14. Thomas GummererAug 20, 2013
  15. 07/24 read-cache: Re-read index if index file changedThomas Gummerer, Aug 18, 2013
  16. 08/24 add documentation for the index apiThomas Gummerer, Aug 18, 2013
  17. Eric SunshineAug 18, 2013
  18. 09/24 read-cache: add index reading apiThomas Gummerer, Aug 18, 2013
  19. 10/24 make sure partially read index is not changedThomas Gummerer, Aug 18, 2013
  20. Eric SunshineAug 18, 2013
  21. Thomas GummererAug 20, 2013
  22. 11/24 grep.c: use index apiThomas Gummerer, Aug 18, 2013
  23. 12/24 ls-files.c: use index apiThomas Gummerer, Aug 18, 2013
  24. 13/24 documentation: add documentation of the index-v5 file formatThomas Gummerer, Aug 18, 2013
  25. 14/24 read-cache: make in-memory format aware of stat_crcThomas Gummerer, Aug 18, 2013
  26. 15/24 read-cache: read index-v5Thomas Gummerer, Aug 18, 2013
  27. Eric SunshineAug 19, 2013
  28. Duy NguyenAug 20, 2013
  29. Thomas GummererAug 20, 2013
  30. Duy NguyenAug 21, 2013
  31. Duy NguyenAug 20, 2013
  32. Thomas GummererAug 20, 2013
  33. Duy NguyenAug 23, 2013
  34. 16/24 read-cache: read resolve-undo dataThomas Gummerer, Aug 18, 2013
  35. Eric SunshineAug 19, 2013
  36. 17/24 read-cache: read cache-tree in index-v5Thomas Gummerer, Aug 18, 2013
  37. Duy NguyenAug 24, 2013
  38. Thomas GummererNov 25, 2013
  39. 18/24 read-cache: write index-v5Thomas Gummerer, Aug 18, 2013
  40. Duy NguyenAug 24, 2013
  41. Thomas GummererNov 25, 2013
  42. Duy NguyenAug 24, 2013
  43. Duy NguyenAug 24, 2013
  44. 19/24 read-cache: write index-v5 cache-tree dataThomas Gummerer, Aug 18, 2013
  45. 20/24 read-cache: write resolve-undo data for index-v5Thomas Gummerer, Aug 18, 2013
  46. 21/24 update-index.c: rewrite index when index-version is givenThomas Gummerer, Aug 18, 2013
  47. 22/24 p0003-index.sh: add perf test for the index formatsThomas Gummerer, Aug 18, 2013
  48. 23/24 introduce GIT_INDEX_VERSION environment variableThomas Gummerer, Aug 18, 2013
  49. Duy NguyenAug 21, 2013
  50. Thomas GummererAug 21, 2013
  51. 24/24 test-lib: allow setting the index format versionThomas Gummerer, Aug 18, 2013
  52. Duy NguyenAug 24, 2013
  53. Junio C HamanoAug 25, 2013
  54. Duy NguyenAug 25, 2013
  55. Thomas GummererAug 31, 2013

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