Intel Extensible Firmware Interface - Manual (Page 379)

Protocols — Bootable Image Support
Version 1.10 12/01/02 11-19
EFI_FILE_IO_INTERFACE.OpenVolume()
Summary
Opens the root directory on a volume.
Prototype
typedef
EFI_STATUS
(EFIAPI *EFI_VOLUME_OPEN) (
IN EFI_FILE_IO_INTERFACE
*This,
OUT EFI_FILE **Root
);
Parameters
This A pointer to the volume to open the root directory of. See the type
EFI_FILE_IO_INTERFACE description.
Root A pointer to the location to return the opened file handle for the root
directory. See the type
EFI_FILE protocol description.
Description
The OpenVolume() function opens a volume, and returns a file handle to the volume’s root
directory. This handle is used to perform all other file I/O operations. The volume remains open
until all the file handles to it are closed.
If the medium is changed while there are open file handles to the volume, all file handles to the
volume will return
EFI_MEDIA_CHANGED . To access the files on the new medium, the volume
must be reopened with OpenVolume() . If the new medium is a different file system than the one
supplied in the EFI_HANDLE ’s DevicePath for the Simple File System protocol,
OpenVolume() will return EFI_UNSUPPORTED .
Status Codes Returned
EFI_SUCCESS The file volume was opened.
EFI_UNSUPPORTED The volume does not support the requested file system type.
EFI_NO_MEDIA The device has no medium.
EFI_DEVICE_ERROR The device reported an error.
EFI_VOLUME_CORRUPTED The file system structures are corrupted.
EFI_ACCESS_DENIED The service denied access to the file.
EFI_OUT_OF_RESOURCES The file volume was not opened.
EFI_MEDIA_CHANGED The device has a different medium in it or the medium is no
longer supported. Any existing file handles for this volume are
no longer valid. To access the files on the new medium, the
volume must be reopened with
OpenVolume() .