diff options
| -rw-r--r-- | share/man/man9/VOP_RDWR.9 | 6 | ||||
| -rw-r--r-- | sys/sys/vnode.h | 2 |
2 files changed, 6 insertions, 2 deletions
diff --git a/share/man/man9/VOP_RDWR.9 b/share/man/man9/VOP_RDWR.9 index 5e67262..a1e28fd 100644 --- a/share/man/man9/VOP_RDWR.9 +++ b/share/man/man9/VOP_RDWR.9 @@ -60,7 +60,11 @@ the credentials of the caller .Pp The .Fa ioflag -argument is a bit mask which can contain the following flags: +argument is used to give directives and hints to the filesystem. +When attempting a read, the high 16 bits are used to provide a +read-ahead hint (in units of filesystem blocks) that the filesystem +should attempt. The low 16 bits are a bit mask which can contain +the following flags: .Bl -tag -width IO_NODELOCKED .It Dv IO_UNIT do I/O as atomic unit diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h index 366c2d5..8046fb8 100644 --- a/sys/sys/vnode.h +++ b/sys/sys/vnode.h @@ -200,7 +200,7 @@ struct vattr { #define VA_EXCLUSIVE 0x02 /* exclusive create request */ /* - * Flags for ioflag. + * Flags for ioflag. (high 16 bits used to ask for read-ahead) */ #define IO_UNIT 0x01 /* do I/O as atomic unit */ #define IO_APPEND 0x02 /* append write to end */ |
