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authorJunio C Hamano <gitster@pobox.com>2019-08-22 19:34:10 (GMT)
committerJunio C Hamano <gitster@pobox.com>2019-08-22 19:34:10 (GMT)
commit207ad3cb203b7adeeb52b5372ace497e20739d49 (patch)
treee98f896ff4dcd71615cbf483f22ee1f42ffb715a /refs
parent77067b6ce8ad9b382fcbaeb012776cd24e88572a (diff)
parenta613d4f8176593e560628b174c3e10cfac3f6d58 (diff)
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Merge branch 'sc/pack-refs-deletion-racefix'
"git pack-refs" can lose refs that are created while running, which is getting corrected. * sc/pack-refs-deletion-racefix: pack-refs: always refresh after taking the lock file
Diffstat (limited to 'refs')
-rw-r--r--refs/packed-backend.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index c01c7f5..4458a0f 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1012,14 +1012,23 @@ int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
}
/*
- * Now that we hold the `packed-refs` lock, make sure that our
- * snapshot matches the current version of the file. Normally
- * `get_snapshot()` does that for us, but that function
- * assumes that when the file is locked, any existing snapshot
- * is still valid. We've just locked the file, but it might
- * have changed the moment *before* we locked it.
+ * There is a stat-validity problem might cause `update-ref -d`
+ * lost the newly commit of a ref, because a new `packed-refs`
+ * file might has the same on-disk file attributes such as
+ * timestamp, file size and inode value, but has a changed
+ * ref value.
+ *
+ * This could happen with a very small chance when
+ * `update-ref -d` is called and at the same time another
+ * `pack-refs --all` process is running.
+ *
+ * Now that we hold the `packed-refs` lock, it is important
+ * to make sure we could read the latest version of
+ * `packed-refs` file no matter we have just mmap it or not.
+ * So what need to do is clear the snapshot if we hold it
+ * already.
*/
- validate_snapshot(refs);
+ clear_snapshot(refs);
/*
* Now make sure that the packed-refs file as it exists in the