ITS#7682 mdb_env_copy(): Avoid Linux O_DIRECT bug.

Use fcntl() to set the flag.  Linux open(,O_DIRECT...) can create
the file even on failure, if the filesystem lacks O_DIRECT support.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index e30d85c476d6d2fe4ed15bc230297ae6d54cc817..46dea53c877d2f0a645d34aaa89345cd801323eb 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -4246,14 +4246,6 @@ mdb_env_copy(MDB_env *env, const char *path)
        newfd = CreateFile(lpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,
                                FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);
 #else
-#ifdef O_DIRECT
-       /* The OS supports O_DIRECT, try with it */
-       newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL|O_DIRECT, 0666);
-       /* But open can fail if O_DIRECT isn't supported by the file system
-        * so retry without the flag
-        */
-       if (newfd == INVALID_HANDLE_VALUE && ErrCode() == EINVAL)
-#endif
        newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL, 0666);
 #endif
        if (newfd == INVALID_HANDLE_VALUE) {
@@ -4261,6 +4253,11 @@ mdb_env_copy(MDB_env *env, const char *path)
                goto leave;
        }
 
+#ifdef O_DIRECT
+       /* Set O_DIRECT if the file system supports it */
+       if ((rc = fcntl(newfd, F_GETFL)) != -1)
+               (void) fcntl(newfd, F_SETFL, rc | O_DIRECT);
+#endif
 #ifdef F_NOCACHE       /* __APPLE__ */
        rc = fcntl(newfd, F_NOCACHE, 1);
        if (rc) {