NAME
inode (vxfs) — format of a VxFS inode
SYNOPSIS
#include <sys/param.h>
#include <sys/kern_sem.h>
#include <sys/fs/vx_hpux.h>
#include <sys/fs/vx_port.h>
#include <sys/fs/vx_inode.h>
DESCRIPTION
The inode list consists of
fs_inopau
inode entries in each allocation unit.
Although a
vxfs
inode is typically 256 bytes in length,
an inode size of 512 bytes can be used instead.
An inode entry has the following format:
- i_mode
The mode and type of file.
- i_nlink
The number of links to the file.
- i_uid
The inode owner.
- i_gid
The inode group.
- i_size
The size in bytes of the file.
Eight bytes have been allocated.
- i_atime
Time of last access,
in
struct timeval
format.
- i_mtime
Time of last modification,
in
struct timeval
format.
- i_ctime
Time of last inode change,
in
struct timeval
format.
- i_aflags
These flags are used to control
the allocation and extension of files.
- VX_AF_IFBAD
If this flag is set,
the inode is invalid in some way.
It should be cleared when
fsck(1M)
is run.
- VX_AF_NOEXTEND
If this flag is set,
the file may not be extended
once the current reservation is exceeded.
The reservation may be increased by the
VX_SETEXT
ioctl,
but the file will not be automatically extended.
- VX_AF_NOGROW
If this flag is set,
the file may not be extended
once the current reservation is exceeded.
It should be cleared on truncation or when
setext(1M)
is run.
This flag is usually set
because an I/O error occurs
while extending a file.
- VX_AF_ALIGN
If this flag is set,
the file must be allocated
in extents of a fixed size and alignment.
If an extent of
i_fixextsize
blocks aligned on an
i_fixextsize
boundary can't be found,
then the allocation will fail.
The alignment is relative to the beginning
of the allocation unit.
- i_orgtype
Mapping type.
Indicates how the inode mapping area
is to be interpreted.
Currently there are three mapping types supported:
- IORG_EXT4
Mapping area consists of an array
of 32-bit extent block addresses and sizes.
- IORG_IMMED
Mapping area itself is a data block.
This mapping is referred to as Immediate Inode Data.
- IORG_TYPED
Mapping area consists of type-extent structures.
- i_eopflags
Extended inode operation flag area.
- i_eopdata
Extended inode operation data area.
- i_ftarea
This is a union.
The contents are determined by file type.
For devices,
the following fields are supported:
- i_rdev
The device number of a block or character special device.
For directories,
the following fields are supported:
- i_dotdot
The parent directory inode inumber
if the inode is a directory.
This replaces the standard ``..'' entry
in the first directory block.
The
vxfs
file system does not have explicit ``.'' and ``..'' entries.
For regular files,
the following fields are supported:
- i_reserve
The number of data blocks reserved
for exclusive use by the file (preallocation).
A preallocation may be requested using
ioctl(2).
See
vxfsio(7).
- i_fixextsize
Set when the inode has a fixed extent size.
The default is to have
a variable extent size allocation policy.
A fixed extent size may be specified using
ioctl(2).
See
vxfsio(7).
For structural files,
the following fields are supported:
- i_matchino
(Version 2 and 3 layouts only.)
The inode number of the ``matching'' inode.
For replicated files,
this is the inode of the replica.
For extent map reorganization files,
this is the inode of the file being reorganized.
- i_fsetindex
(Version 2 and 3 layouts only.)
The index of the fileset associated with this inode.
- i_blocks
The number of blocks
currently allocated to the file,
including any blocks allocated
for indirect address extents.
- i_gen
The generation number.
A serial number which is incremented
whenever the inode is freed and reallocated.
It is designed to provide a ``handle''
for stateless servers such as NFS.
- i_vversion
A count of the number of times
the inode metadata has been modified.
This field is a 64-bit number.
- ic_org
The mapping area.
This field is a union based on the value of
i_orgtype
and the file system type.
For the
vxfs
IORG_IMMED
organization type,
the following structure is used:
- i_immed
The Immediate Inode data area,
NIMMED_N
(currently 96) bytes in length
(see
fs_immedlen).
Any directory or symbolic link
which is <= 96 bytes in length
will be stored directly in the inode.
For the
vxfs
IORG_EXT4
organization type,
the following structure is used:
- i_ies
Indirect extent size.
This is the size in blocks
of the indirect data extents
in the file.
- i_ie
Array of indirect address extents.
There are
NIADDR
(currently 2) indirect address extents.
The indirect address extents are 8192 bytes long.
Each indirect address extent
may contain up to 2048 extent addresses.
The first indirect address extent
is used for single indirection.
With single indirection,
each entry in the indirect address extent
indicates the starting block number
of a data extent.
The second indirect address extent
is a double indirect address extent.
With double indirection,
each entry in the indirect address extent
indicates the starting block number
of a single indirect address extent.
- i_dext
An array of structures
containing the direct extent addresses and sizes.
Up to
NDADDR_N
(currently ten) direct extents are supported.
Since a variable length extent allocation policy is used,
each direct extent may have a different size.
Each structure contains the following elements:
- i_de
Direct extent address.
- i_des
Direct extent size.
- i_iattrino
(Version 2 and 3 layouts only.)
Indirect attribute inode.
This identifies the inode in the attribute fileset
that contains indirect attribute references.
The remaining bytes of the inode
are reserved for extended attribute records,
which are formatted as follows:
- length
The exact length of the attribute record.
If this is not a multiple of 4 bytes,
the start of the next attribute record is found
by rounding the length up to a 4 byte boundary.
- format
The format of the data layout
of the remainder of the attribute record.
Each attribute consists of a class
identifying the attribute's administrative domain;
a subclass identifying the attribute
within the administrative domain;
and data.
The valid record formats are:
- ATTR_EXTIMMED
This record extends the immediate data area
so that files larger than 96 bytes
can be stored directly in the inode.
- ATTR_IMMED
The attribute is stored directly in the inode.
The fields in the rest of this record are:
- class
The class of the attribute.
- subclass
The subclass of the attribute.
- data
The attribute data.
- ATTR_DIRECT
When attributes are too large
to store directly in the inode,
each attribute is stored in its own file.
This record lists each attribute
along with the inode number
corresponding to the file
in which the attribute is stored.
The number of entries in the list
is determined by the length of the record.
The fields in each entry are:
- class
The class of the attribute.
- subclass
The subclass of the attribute.
- length
The length of the attribute data.
This allows attribute operations
to check the length of an attribute
without reading the attribute inode.
- inumber
The inode number of the file
containing the attribute data.
The inode is part of the attribute fileset.
The attribute records in the inode
are terminated by a record
with a format of zero
(for compatibility with file systems
that have the last 80 bytes of all inodes
set to NULL).
