запросить информацию об открытом файле (query information for an open file)
Имя (Name)
ioctl_xfs_fsgetxattr - query information for an open file
Синопсис (Synopsis)
#include <linux/fs.h>
int ioctl(int fd, XFS_IOC_FSGETXATTR, struct fsxattr *arg);
int ioctl(int fd, XFS_IOC_FSGETXATTRA, struct fsxattr *arg);
int ioctl(int fd, XFS_IOC_FSSETXATTR, struct fsxattr *arg);
Описание (Description)
Query or set additional attributes associated with files in
various file systems. The attributes are conveyed in a structure
of the form:
struct fsxattr {
__u32 fsx_xflags;
__u32 fsx_extsize;
__u32 fsx_nextents;
__u32 fsx_projid;
__u32 fsx_cowextsize;
unsigned char fsx_pad[8];
};
fsx_xflags are extended flags that apply to this file. Refer to
the section XFS INODE FLAGS below for more information.
fsx_extsize is the preferred extent allocation size for data
blocks mapped to this file, in units of filesystem blocks. If
this value is zero, the filesystem will choose a default option,
which is currently zero. If XFS_IOC_FSSETXATTR is called with
XFS_XFLAG_EXTSIZE set in fsx_xflags and this field set to zero,
the XFLAG will also be cleared.
fsx_nextents is the number of data extents in this file. If
XFS_IOC_FSGETXATTRA was used, then this is the number of extended
attribute extents in the file.
fsx_projid is the project ID of this file.
fsx_cowextsize is the preferred extent allocation size for copy
on write operations targeting this file, in units of filesystem
blocks. If this field is zero, the filesystem will choose a
default option, which is currently 128 filesystem blocks. If
XFS_IOC_FSSETXATTR is called with XFS_XFLAG_COWEXTSIZE set in
fsx_xflags and this field set to zero, the XFLAG will also be
cleared.
fsx_pad must be zeroed.
Флаги inode XFS (XFS inode flags)
This field can be a combination of the following:
XFS_XFLAG_REALTIME
The file is a realtime file. This bit can only be changed
on a file when it has no allocated extents.
XFS_XFLAG_PREALLOC
The file has preallocated space.
XFS_XFLAG_IMMUTABLE
The file is immutable - it cannot be modified, deleted or
renamed, no link can be created to this file and no data
can be written to the file. Only the superuser or a
process possessing the CAP_LINUX_IMMUTABLE capability can
set or clear this flag. If this flag is set before a
XFS_IOC_FSSETXATTR call and would not be cleared by the
call, then no other attributes can be changed and EPERM
will be returned.
XFS_XFLAG_APPEND
The file is append-only - it can only be opened in append
mode for writing. For directories, this means that files
cannot be unlinked from this directory. Only the
superuser or a process possessing the CAP_LINUX_IMMUTABLE
capability can set or clear this flag.
XFS_XFLAG_SYNC
All writes to the file are synchronous. If set on a
directory and the /proc/sys/fs/xfs/inherit_sync tunable is
set to 1, new files and subdirectories created in the
directory will also have the flag set.
XFS_XFLAG_NOATIME
When the file is accessed, its atime record is not
modified. If set on a directory and the
/proc/sys/fs/xfs/inherit_noatime tunable is set to 1, new
files and subdirectories created in the directory will
also have the flag set.
XFS_XFLAG_NODUMP
The file should be skipped by backup utilities. If set on
a directory and the /proc/sys/fs/xfs/inherit_nodump
tunable is set to 1, new files and subdirectories created
in the directory will also have the flag set.
XFS_XFLAG_RTINHERIT
Realtime inheritance bit - new files created in the
directory will be automatically created as realtime files.
If set on a directory, new subdirectories created in the
directory will also have the inheritance flag set.
XFS_XFLAG_PROJINHERIT
Project inheritance bit - new files and directories
created in this directory will inherit the project ID of
this directory. If set on a directory, new subdirectories
created in the directory will also have the inheritance
flag set.
XFS_XFLAG_NOSYMLINKS
Disallows creation of symbolic links in the directory.
This flag can only be set on a directory. If set on a
directory and the /proc/sys/fs/xfs/inherit_nosymlinks
tunable is set to 1, new files and subdirectories created
in the directory will also have the flag set.
XFS_XFLAG_EXTSIZE
Extent size bit - if a basic extent size value is set on
the file then the allocator will allocate in multiples of
the set size for this file (see fsx_extsize below). The
extent size can only be changed on a file when it has no
allocated extents.
XFS_XFLAG_EXTSZINHERIT
Extent size inheritance bit - new files and directories
created in the directory will inherit the extent size
value (see fsx_extsize below) of the parent directory.
New subdirectories created in the directory will inherit
the extent size inheritance bit.
XFS_XFLAG_NODEFRAG
No defragment file bit - the file should be skipped during
a defragmentation operation. If set on a directory and
the /proc/sys/fs/xfs/inherit_nodefrag tunable is set to 1,
new files and subdirectories created in the directory will
also have the flag set.
XFS_XFLAG_FILESTREAM
Filestream allocator bit - allows a directory to reserve
an allocation group for exclusive use by files created
within that directory. Files being written in other
directories will not use the same allocation group and so
files within different directories will not interleave
extents on disk. The reservation is only active while
files are being created and written into the directory.
If set on a directory, new files and subdirectories
created in the directory will also have the flag set.
XFS_XFLAG_DAX
If the filesystem lives on directly accessible persistent
memory, reads and writes to this file will go straight to
the persistent memory, bypassing the page cache. If set
on a directory, new files and subdirectories created in
the directory will also have the flag set. This flag
cannot be set on filesystems which have the reflink
feature enabled.
XFS_XFLAG_COWEXTSIZE
Copy on Write Extent size bit - if a CoW extent size value
is set on the file, the allocator will allocate extents
for staging a copy on write operation in multiples of the
set size for this file (see fsx_cowextsize below). If set
on a directory, new files and subdirectories created in
the directory will have both the flag and the CoW extent
size value set.
XFS_XFLAG_HASATTR
The file has extended attributes associated with it.
Возвращаемое значение (Return value)
On error, -1 is returned, and errno is set to indicate the error.
Ошибки (Error)
Error codes can be one of, but are not limited to, the following:
EACCESS
Caller does not have sufficient access to change the
attributes.
EFAULT The kernel was not able to copy into the userspace buffer.
EFSBADCRC
Metadata checksum validation failed while performing the
query.
EFSCORRUPTED
Metadata corruption was encountered while performing the
query.
EINVAL One of the arguments was not valid.
EIO An I/O error was encountered while performing the query.
ENOMEM There was insufficient memory to perform the query.
EPERM Caller did not have permission to change the attributes.
Стандарты (Conforming to)
This API is implemented by the ext4, xfs, btrfs, and f2fs
filesystems on the Linux kernel. Not all fields may be
understood by filesystems other than xfs.
Смотри также (See also)
ioctl(2), ioctl_iflags(2)
