---
title: vfs_unmountbyfsid
framework: Kernel
role: symbol
role_heading: Function
platforms: [macOS 10.5+]
path: kernel/1523503-vfs_unmountbyfsid
---

# vfs_unmountbyfsid

Find a filesystem by ID and unmount it.

## Declaration

```occ
int vfs_unmountbyfsid(fsid_t *fsid, int flags, vfs_context_t ctx);
```

## Parameters

- `fsid`: ID of filesystem to unmount, as found through (for example) statfs.
- `flags`: MNT_FORCE: forcibly invalidate files open on the mount (though in-flight I/O operations will be allowed to complete).
- `ctx`: Context against which to authenticate unmount operation.

## Return Value

Return Value 0 for succcess, nonero for failure.