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NETWORK_APP_INSTANCE_EA structure (ntifs.h)

  • Article

An Extended Attribute (EA) structure for processes using Server Message Block (SMB) Cluster Client Failover.

Syntax

typedef struct _NETWORK_APP_INSTANCE_EA {
  GUID  AppInstanceID;
  ULONG CsvFlags;
} NETWORK_APP_INSTANCE_EA, *PNETWORK_APP_INSTANCE_EA;

Members

AppInstanceID

A GUID that identifies a single application instance, or a NETWORK_APP_INSTANCE_EA structure when the application additionally contains a flag for CsvFlags.

CsvFlags

An optional flag: NETWORK_APP_INSTANCE_CSV_FLAGS_VALID_ONLY_IF_CSV_COORDINATOR (0x00000001)

The NETWORK_APP_INSTANCE_CSV_FLAGS_VALID_ONLY_IF_CSV_COORDINATOR flag is only used when the file is opened directly from CSVFS. This flag is ignored when the file is opened using the SMB protocol. The flag notifies CSVFS that the file only be opened on the coordinating node. If an ‘open’ request is sent to CSVFS and the node is non-coordinating, then the open will fail. Additionally, if the coordinating node is moved while the file is opened, the file open would be invalidated.

Remarks

A process can register a CCF application ID using RegisterAppInstance, enabling all 'open' operations from the process to have the same ApplicationId. If an ID isn't registered, the ApplicationId will differ for each operation.

To mark individual open operations with a different ApplicationId, first set AppInstanceID to a GUID value. you can then append SMB_CCF_APP_INSTANCE_EA_NAME to the list of Extended Attributes when calling NtCreateFile. If the application also passes the NETWORK_APP_INSTANCE_CSV_FLAGS_VALID_ONLY_IF_CSV_COORDINATOR flag, then AppInstanceID should be NETWORK_APP_INSTANCE_EA structure.

Requirements

Requirement Value
Minimum supported client Windows 8
Minimum supported server Windows Server 2012
Header ntifs.h