commit ef99fdb1099b987bfaed49367904342f77da3e43
from: Stefan Sperling <stsp@stsp.name>
date: Sun Mar 11 01:31:27 2018 UTC

use flock(2) because open(2) O_NONBLOCK also enables non-blocking I/O

commit - 73a5ef678f0ee5f125fa5154baffb9cde3a1b133
commit + ef99fdb1099b987bfaed49367904342f77da3e43
blob - 3a8dd15749445c01ce379f9b5bae078a58365c39
blob + 04c8fc0fc3ec37db221182a522c6955555eec78b
--- lib/worktree.c
+++ lib/worktree.c
@@ -94,8 +94,12 @@ read_meta_file(char **content, const char *gotpath, co
 		goto done;
 	}
 
-	fd = open(path, O_RDONLY | O_EXLOCK | O_NONBLOCK | O_NOFOLLOW);
+	fd = open(path, O_RDONLY | O_NOFOLLOW);
 	if (fd == -1) {
+		err = got_error_from_errno();
+		goto done;
+	}
+	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
 		    : got_error_from_errno());
 		goto done;
@@ -233,9 +237,12 @@ got_worktree_open(struct got_worktree **worktree, cons
 		goto done;
 	}
 
-	fd = open(path_fileindex, O_RDWR | O_EXLOCK | O_NONBLOCK | O_NOFOLLOW,
-	    GOT_DEFAULT_FILE_MODE);
+	fd = open(path_fileindex, O_RDWR | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
 	if (fd == -1) {
+		err = got_error_from_errno();
+		goto done;
+	}
+	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
 		    : got_error_from_errno());
 		goto done;