From: Michael Haggerty <mhagger@alum.mit.edu>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Jonathan Nieder" <jrnieder@gmail.com>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Stefan Beller" <sbeller@google.com>, "Jeff King" <peff@peff.net>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"David Turner" <novalis@novalis.org>,
"Brandon Williams" <bmwill@google.com>,
git@vger.kernel.org, "Michael Haggerty" <mhagger@alum.mit.edu>
Subject: [PATCH] packed_ref_store: handle a packed-refs file that is a symlink
Date: Wed, 26 Jul 2017 16:39:42 -0700 [thread overview]
Message-ID: <d0da02a8b6f0272fa70ae3b1dc80fee6c6ee8d18.1501111803.git.mhagger@alum.mit.edu> (raw)
In-Reply-To: <20170720232040.GA159617@aiede.mtv.corp.google.com>
One of the tricks that `contrib/workdir/git-new-workdir` plays is to
making `packed-refs` in the new workdir a symlink to the `packed-refs`
file in the original repository. Before
42dfa7ecef ("commit_packed_refs(): use a staging file separate from
the lockfile", 2017-06-23), a lockfile was used as the staging file,
and because the `LOCK_NO_DEREF` was not used, the pointed-to file was
locked and modified.
But after that commit, the staging file was created using a tempfile,
with the end result that rewriting the `packed-refs` file in the
workdir overwrote the symlink rather than the original `packed-refs`
file.
Change `commit_packed_refs()` to use `get_locked_file_path()` to find
the path of the file that it should overwrite. Since that path was
properly resolved when the lockfile was created, this restores the
pre-42dfa7ecef behavior.
Also add a test case to document this use case and prevent a
regression like this from recurring.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
Sorry for the slow response; I've been traveling and very busy.
I didn't even know that a symlinked `packed-refs` file is a thing. The
attached patch should fix the problem. It applies on top of v3 of
mh/packed-ref-store [1] (which is already in next).
Michael
[1] http://public-inbox.org/git/cover.1498933362.git.mhagger@alum.mit.edu/
refs/packed-backend.c | 24 ++++++++++++++++++------
t/t3210-pack-refs.sh | 15 +++++++++++++++
2 files changed, 33 insertions(+), 6 deletions(-)
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index a28befbfa3..59e7d1a509 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -610,19 +610,27 @@ int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err)
struct packed_ref_cache *packed_ref_cache =
get_packed_ref_cache(refs);
int ok;
+ int ret = -1;
struct strbuf sb = STRBUF_INIT;
FILE *out;
struct ref_iterator *iter;
+ char *packed_refs_path;
if (!is_lock_file_locked(&refs->lock))
die("BUG: commit_packed_refs() called when unlocked");
- strbuf_addf(&sb, "%s.new", refs->path);
+ /*
+ * If packed-refs is a symlink, we want to overwrite the
+ * symlinked-to file, not the symlink itself. Also, put the
+ * staging file next to it:
+ */
+ packed_refs_path = get_locked_file_path(&refs->lock);
+ strbuf_addf(&sb, "%s.new", packed_refs_path);
if (create_tempfile(&refs->tempfile, sb.buf) < 0) {
strbuf_addf(err, "unable to create file %s: %s",
sb.buf, strerror(errno));
strbuf_release(&sb);
- return -1;
+ goto out;
}
strbuf_release(&sb);
@@ -660,17 +668,21 @@ int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err)
goto error;
}
- if (rename_tempfile(&refs->tempfile, refs->path)) {
+ if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
strbuf_addf(err, "error replacing %s: %s",
refs->path, strerror(errno));
- return -1;
+ goto out;
}
- return 0;
+ ret = 0;
+ goto out;
error:
delete_tempfile(&refs->tempfile);
- return -1;
+
+out:
+ free(packed_refs_path);
+ return ret;
}
/*
diff --git a/t/t3210-pack-refs.sh b/t/t3210-pack-refs.sh
index 2bb4b25ed9..0d8a03e2a9 100755
--- a/t/t3210-pack-refs.sh
+++ b/t/t3210-pack-refs.sh
@@ -238,4 +238,19 @@ test_expect_success 'retry acquiring packed-refs.lock' '
git -c core.packedrefstimeout=3000 pack-refs --all --prune
'
+test_expect_success 'pack symlinked packed-refs' '
+ # First make sure that symlinking works when reading:
+ git update-ref refs/heads/loosy refs/heads/master &&
+ git for-each-ref >all-refs-before &&
+ mv .git/packed-refs .git/my-deviant-packed-refs &&
+ ln -s my-deviant-packed-refs .git/packed-refs &&
+ git for-each-ref >all-refs-linked &&
+ test_cmp all-refs-before all-refs-linked &&
+ git pack-refs --all --prune &&
+ git for-each-ref >all-refs-packed &&
+ test_cmp all-refs-before all-refs-packed &&
+ test -h .git/packed-refs &&
+ test "$(readlink .git/packed-refs)" = "my-deviant-packed-refs"
+'
+
test_done
--
2.11.0
next prev parent reply other threads:[~2017-07-26 23:39 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-01 18:30 [PATCH v3 00/30] Create a reference backend for packed refs Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 01/30] t1408: add a test of stale packed refs covered by loose refs Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 02/30] add_packed_ref(): teach function to overwrite existing refs Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 03/30] packed_ref_store: new struct Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 04/30] packed_ref_store: move `packed_refs_path` here Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 05/30] packed_ref_store: move `packed_refs_lock` member here Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 06/30] clear_packed_ref_cache(): take a `packed_ref_store *` parameter Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 07/30] validate_packed_ref_cache(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 08/30] get_packed_ref_cache(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 09/30] get_packed_refs(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 10/30] add_packed_ref(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 11/30] lock_packed_refs(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 12/30] commit_packed_refs(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 13/30] rollback_packed_refs(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 14/30] get_packed_ref(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 15/30] repack_without_refs(): " Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 16/30] packed_peel_ref(): new function, extracted from `files_peel_ref()` Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 17/30] packed_ref_store: support iteration Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 18/30] packed_read_raw_ref(): new function, replacing `resolve_packed_ref()` Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 19/30] packed-backend: new module for handling packed references Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 20/30] packed_ref_store: make class into a subclass of `ref_store` Michael Haggerty
2017-07-01 18:30 ` [PATCH v3 21/30] commit_packed_refs(): report errors rather than dying Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 22/30] commit_packed_refs(): use a staging file separate from the lockfile Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 23/30] packed_refs_lock(): function renamed from lock_packed_refs() Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 24/30] packed_refs_lock(): report errors via a `struct strbuf *err` Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 25/30] packed_refs_unlock(), packed_refs_is_locked(): new functions Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 26/30] clear_packed_ref_cache(): don't protest if the lock is held Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 27/30] commit_packed_refs(): remove call to `packed_refs_unlock()` Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 28/30] repack_without_refs(): don't lock or unlock the packed refs Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 29/30] t3210: add some tests of bogus packed-refs file contents Michael Haggerty
2017-07-01 18:31 ` [PATCH v3 30/30] read_packed_refs(): die if `packed-refs` contains bogus data Michael Haggerty
2017-07-05 9:12 ` [PATCH v3 00/30] Create a reference backend for packed refs Jeff King
2017-07-20 23:05 ` Stefan Beller
2017-07-20 23:20 ` Jonathan Nieder
2017-07-26 23:39 ` Michael Haggerty [this message]
2017-07-27 0:15 ` [PATCH] packed_ref_store: handle a packed-refs file that is a symlink Stefan Beller
2017-07-27 0:18 ` Jonathan Nieder
2017-07-27 11:12 ` Michael Haggerty
2017-07-27 17:19 ` Junio C Hamano
2017-07-27 18:28 ` Jeff King
2017-07-27 19:40 ` Junio C Hamano
2017-07-28 6:07 ` Michael Haggerty
2021-05-31 14:18 ` Ævar Arnfjörð Bjarmason
2021-06-03 19:39 ` Jeff King
2021-06-03 19:58 ` [PATCH] t: use portable wrapper for readlink(1) Jeff King
2021-06-04 21:09 ` Ævar Arnfjörð Bjarmason
2021-06-03 20:23 ` [PATCH] packed_ref_store: handle a packed-refs file that is a symlink Felipe Contreras
2021-06-03 21:08 ` Jeff King
2021-06-03 22:25 ` Felipe Contreras
2021-06-04 21:37 ` Ævar Arnfjörð Bjarmason
2021-06-05 1:07 ` Felipe Contreras
2021-06-04 21:12 ` Ævar Arnfjörð Bjarmason
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