We will want to be able to hold the lockfile for `packed-refs` even
after we have activated the new values. So use a separate tempfile,
`packed-refs.new`, as a place to stage the new contents of the
`packed-refs` file. For now this is all done within
`commit_packed_refs()`, but that will change shortly.
Signed-off-by: Michael Haggerty <mhag...@alum.mit.edu>
---
refs/packed-backend.c | 40 ++++++++++++++++++++++++++++++++--------
1 file changed, 32 insertions(+), 8 deletions(-)
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 5bee49d497..6619052e96 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -68,6 +68,13 @@ struct packed_ref_store {
* thus the enclosing `packed_ref_store`) must not be freed.
*/
struct lock_file lock;
+
+ /*
+ * Temporary file used when rewriting new contents to the
+ * "packed-refs" file. Note that this (and thus the enclosing
+ * `packed_ref_store`) must not be freed.
+ */
+ struct tempfile tempfile;
};
struct ref_store *packed_ref_store_create(const char *path,
@@ -522,10 +529,16 @@ int lock_packed_refs(struct ref_store *ref_store, int
flags)
timeout_configured = 1;
}
+ /*
+ * Note that we close the lockfile immediately because we
+ * don't write new content to it, but rather to a separate
+ * tempfile.
+ */
if (hold_lock_file_for_update_timeout(
&refs->lock,
refs->path,
- flags, timeout_value) < 0)
+ flags, timeout_value) < 0 ||
+ close_lock_file(&refs->lock))
return -1;
/*
@@ -567,13 +580,23 @@ int commit_packed_refs(struct ref_store *ref_store,
struct strbuf *err)
get_packed_ref_cache(refs);
int ok;
int ret = -1;
+ struct strbuf sb = STRBUF_INIT;
FILE *out;
struct ref_iterator *iter;
if (!is_lock_file_locked(&refs->lock))
die("BUG: commit_packed_refs() called when unlocked");
- out = fdopen_lock_file(&refs->lock, "w");
+ strbuf_addf(&sb, "%s.new", 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);
+ goto out;
+ }
+ strbuf_release(&sb);
+
+ out = fdopen_tempfile(&refs->tempfile, "w");
if (!out) {
strbuf_addf(err, "unable to fdopen packed-refs tempfile: %s",
strerror(errno));
@@ -582,7 +605,7 @@ int commit_packed_refs(struct ref_store *ref_store, struct
strbuf *err)
if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0) {
strbuf_addf(err, "error writing to %s: %s",
- get_lock_file_path(&refs->lock), strerror(errno));
+ get_tempfile_path(&refs->tempfile),
strerror(errno));
goto error;
}
@@ -594,7 +617,7 @@ int commit_packed_refs(struct ref_store *ref_store, struct
strbuf *err)
if (write_packed_entry(out, iter->refname, iter->oid->hash,
peel_error ? NULL : peeled.hash)) {
strbuf_addf(err, "error writing to %s: %s",
- get_lock_file_path(&refs->lock),
+ get_tempfile_path(&refs->tempfile),
strerror(errno));
ref_iterator_abort(iter);
goto error;
@@ -602,13 +625,13 @@ int commit_packed_refs(struct ref_store *ref_store,
struct strbuf *err)
}
if (ok != ITER_DONE) {
- strbuf_addf(err, "unable to write packed-refs file: "
+ strbuf_addf(err, "unable to rewrite packed-refs file: "
"error iterating over old contents");
goto error;
}
- if (commit_lock_file(&refs->lock)) {
- strbuf_addf(err, "error overwriting %s: %s",
+ if (rename_tempfile(&refs->tempfile, refs->path)) {
+ strbuf_addf(err, "error replacing %s: %s",
refs->path, strerror(errno));
goto out;
}
@@ -617,9 +640,10 @@ int commit_packed_refs(struct ref_store *ref_store, struct
strbuf *err)
goto out;
error:
- rollback_lock_file(&refs->lock);
+ delete_tempfile(&refs->tempfile);
out:
+ rollback_lock_file(&refs->lock);
release_packed_ref_cache(packed_ref_cache);
return ret;
}
--
2.11.0
