From e0a8e194a2e3ca0a405dadfcbc9b5347e46fe8c0 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 7 Jun 2017 22:28:23 +1000 Subject: [PATCH] core/mount: pass "-c" flag to /bin/umount (#6093) "-c", which is short for "--no-canonicalize", tells /bin/umount that the path name is canonical (no .. or symlinks etc). systemd always uses a canonical name, so this flag is appropriate for systemd to use. Knowing that the path is canonical allows umount to avoid some calls to lstat() on the path. From v2.30 "-c" goes further and causes umount to avoid all attempts to 'lstat()' (or similar) the path. This is important when automatically unmounting a filesystem, as lstat() can hang indefinitely in some cases such as when an NFS server is not accessible. "-c" has been supported since util-linux 2.17 which is before the earliest version supported by systemd. So "-c" is safe to use now, and once util-linux v2.30 is in use, it will allow mounts from non-responsive NFS servers to be unmounted. (cherry picked from commit 83897d5470190a9818df50026cf38cd97114f77d) --- src/core/mount.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/core/mount.c b/src/core/mount.c index ca0c4b0d5e..214364d87d 100644 --- a/src/core/mount.c +++ b/src/core/mount.c @@ -886,7 +886,7 @@ static void mount_enter_unmounting(Mount *m) { m->control_command_id = MOUNT_EXEC_UNMOUNT; m->control_command = m->exec_command + MOUNT_EXEC_UNMOUNT; - r = exec_command_set(m->control_command, UMOUNT_PATH, m->where, NULL); + r = exec_command_set(m->control_command, UMOUNT_PATH, m->where, "-c", NULL); if (r >= 0 && m->lazy_unmount) r = exec_command_append(m->control_command, "-l", NULL); if (r >= 0 && m->force_unmount)