rename_tmp_log(): handle a possible mkdir/rmdir race

diff --git a/refs.c b/refs.c
index a09bbb768d5412573a3bd42364e769f7bb3c63a8..bbcdc88e418efd8b681fd59d0fe0ad9fefd8a34e 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -2528,6 +2528,44 @@ int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
  */
 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
 
+static int rename_tmp_log(const char *newrefname)
+{
+       int attempts_remaining = 3;
+
+ retry:
+       if (safe_create_leading_directories(git_path("logs/%s", newrefname))) {
+               error("unable to create directory for %s", newrefname);
+               return -1;
+       }
+
+       if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
+               if (errno==EISDIR || errno==ENOTDIR) {
+                       /*
+                        * rename(a, b) when b is an existing
+                        * directory ought to result in ISDIR, but
+                        * Solaris 5.8 gives ENOTDIR.  Sheesh.
+                        */
+                       if (remove_empty_directories(git_path("logs/%s", newrefname))) {
+                               error("Directory not empty: logs/%s", newrefname);
+                               return -1;
+                       }
+                       goto retry;
+               } else if (errno == ENOENT && --attempts_remaining > 0) {
+                       /*
+                        * Maybe another process just deleted one of
+                        * the directories in the path to newrefname.
+                        * Try again from the beginning.
+                        */
+                       goto retry;
+               } else {
+                       error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
+                               newrefname, strerror(errno));
+                       return -1;
+               }
+       }
+       return 0;
+}
+
 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
 {
        unsigned char sha1[20], orig_sha1[20];
@@ -2575,30 +2613,9 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
                }
        }
 
-       if (log && safe_create_leading_directories(git_path("logs/%s", newrefname))) {
-               error("unable to create directory for %s", newrefname);
+       if (log && rename_tmp_log(newrefname))
                goto rollback;
-       }
 
- retry:
-       if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
-               if (errno==EISDIR || errno==ENOTDIR) {
-                       /*
-                        * rename(a, b) when b is an existing
-                        * directory ought to result in ISDIR, but
-                        * Solaris 5.8 gives ENOTDIR.  Sheesh.
-                        */
-                       if (remove_empty_directories(git_path("logs/%s", newrefname))) {
-                               error("Directory not empty: logs/%s", newrefname);
-                               goto rollback;
-                       }
-                       goto retry;
-               } else {
-                       error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
-                               newrefname, strerror(errno));
-                       goto rollback;
-               }
-       }
        logmoved = log;
 
        lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);