Function
The vn_fsync operation writes to
disk (or otherwise stabilizes) all changed data in a file.
Input parameter format
vn_fsync (Token_structure,
OSI_structure,
Audit_structure,
Return_value,
Return_code,
Reason_code)
Parameters
- Token_structure
- Supplied parameter
- Type:
- TOKSTR
- Length:
- Specified by TOKSTR.ts_hdr.cblen.
The Token_structure represents the file (vnode)
that is being operated on. It contains the PFS's initialization token,
mount token, and the file token. Refer to LFS/PFS control block structure for
a discussion of this structure, and to the TOKSTR typedef in BPXYPFSI
in Interface structures for C language servers and clients for its mapping.
- OSI_structure
- Supplied and returned parameter
- Type:
- OSI
- Length:
- Specified by OSI.osi_hdr.cblen.
The OSI_structure contains information that is used
by the OSI operations that may be called by the PFS. See OSI services for more information.
It also contains
MVS-specific information that needs to be passed to the PFS, including
SMF accounting fields, a work area, a recovery area, and an optional
pointer to an output ATTR structure. For more details on the OSI structure,
see The OSI structure.
This area is mapped by
the OSI typedef in BPXYPFSI in Interface structures for C language servers and clients.
- Audit_structure
- Supplied parameter
- Type:
- CRED
- Length:
- Specified by CRED.cred_hdr.cblen.
The Audit_structure contains information that is
used by the security product for access checks and auditing. It is
passed to most SAF routines that are invoked by the PFS.
Refer
to Security responsibilities and considerations for a discussion of security processing,
and to the CRED typedef in BPXYPFSI in Interface structures for C language servers and clients for
the mapping of this structure.
- Return_value
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
A fullword in which the vn_fsync service returns
the results of the operation, as one of the following:
- Return_value
- Meaning
- -1
- The operation was not successful. The Return_code and Reason_Code
values must be filled in by the PFS when Return_value is -1.
- 0
- The operation was successful.
- Return_code
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
A fullword in which the vn_fsync service stores
the return code. The vn_fsync service returns Return_code only if
Return_value is -1. See z/OS UNIX System Services Messages and Codes for
a complete list of supported return code values.
The
vn_fsync service should support at least the following error value:
| Return_code |
Explanation |
|---|
| EINVAL |
The operation is not possible for the specified file. |
- Reason_code
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
A fullword in which the vn_fsync service stores
the reason code. The vn_fsync service returns Reason_code only if
Return_value is -1. Reason_code further qualifies
the Return_code value. These reason codes are documented by the PFS.
Implementation notes
- Overview of vn_fsync processing
For the file token in the token_structure, vn_fsync must write
all modified data that is not yet placed in nonvolatile storage to
such a medium.
- Specific processing notes
- Data should be completely hardened before vn_fsync returns to
its caller.
- For more information about the semantics of this operation for
a POSIX-conforming PFS, refer to the fsync() function
in the POSIX .1a standard (IEEE Std 1003.1a),
draft 7.
- Serialization provided by the LFS
The vn_fsync operation is invoked with an exclusive latch held
on the vnode of the file.
- Security calls to be made by the PFS
- None.
z/OS UNIX System Services File System Interface Reference
Copyright IBM Corporation 1990, 2014