Reads or writes data to or from a file.
vp | Points to the vnode to be read or written. |
rw | Specifies a flag indicating read or write. |
fflags | Specifies the file flags. |
uiop | Points to the uiop structure describing the operation. |
ext | Specifies the extension parameter passed to readx or writex. |
vinfo | Specifies the vinfo parameter from the file table entry. |
prevap | Points to an attributes structure for pre-operation attributes. |
postvap | Points to an attributes structure for post-operation attributes. |
crp | Specifies user's credentials. |
The vn_rdwr_attr entry point is used to read and write files. The arguments are identical to the vn_rdwr entry point. The prevap and postvap pointers are used to return file attributes before and after the operation.
File systems that do not define GFS_VERSION421 in their gfs flags do not need to supply a vn_rdwr_attr entry point.
The vn_rdwr_attr entry point can be called from the process environment only.
Zero | Indicates a successful operation. |
Nonzero | Indicates that the operation failed; return values should be chosen from the /usr/include/sys/errno.h file. |
Virtual File System Overview, Logical File System Overview, Understanding Virtual Nodes (V-nodes), and Virtual File System Kernel Extensions Overview.
List of Virtual File System Operations.