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NAME | SYNOPSIS | DESCRIPTION | SAMPLE PROGRAM | RETURN VALUE | ERRORS | CONFORMING TO | SEE ALSO | COLOPHON |
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IOCTL-XFS-GETPARENTS(2) System Calls Manual IOCTL-XFS-GETPARENTS(2)
ioctl_xfs_getparents - query XFS directory parent information
#include <xfs/xfs_fs.h>
int ioctl(int fd, XFS_IOC_GETPARENTS, struct xfs_getparents *arg);
int ioctl(int fd, XFS_IOC_GETPARENTS_BY_HANDLE, struct
xfs_getparents_by_handle *arg);
This command is used to retrieve the directory parent pointers of
either the currently opened file or a file handle. Parent
pointers point upwards in the directory tree from a child file
towards a parent directories. Each entry in a parent directory
must have a corresponding parent pointer in the child.
Calling programs should allocate a large memory buffer and
initialize a header of the following form:
struct xfs_getparents {
struct xfs_attrlist_cursor gp_cursor;
__u16 gp_iflags;
__u16 gp_oflags;
__u32 gp_bufsize;
__u64 __pad;
__u64 gp_buffer;
};
struct xfs_getparents {
struct xfs_handle gph_handle;
struct xfs_getparents gph_request;
};
The field gp_cursor tracks the progress of iterating through the
parent pointers. Calling programs must initialize this to zero
before the first system call and must not touch it after that.
The field gp_iflags control the behavior of the query operation
and provide more information about the outcome of the operation.
There are no input flags currently defined; this field must be
zero.
The field gp_oflags contains information about the query itself.
Possibly output flags are:
XFS_GETPARENTS_OFLAG_ROOT
The file queried was the root directory.
XFS_GETPARENTS_OFLAG_DONE
There are no more parent pointers to query.
The field __pad must be zero.
The field gp_bufsize should be set to the size of the buffer, in
bytes.
The field gp_buffer should point to an output buffer for the
parent pointer records.
Parent pointer records are returned in the following form:
struct xfs_getparents_rec {
struct xfs_handle gpr_parent;
__u16 gpr_reclen;
char gpr_name[];
};
The field gpr_parent is a file handle that can be used to open the
parent directory.
The field gpr_reclen will be set to the number of bytes used by
this parent record.
The array gpr_name will be set to a NULL-terminated byte sequence
representing the filename stored in the parent pointer. If the
name is a zero-length string, the file queried has no parents.
Calling programs should allocate a large memory buffer, initialize
the head structure to zeroes, set gp_bufsize to the size of the
buffer, and call the ioctl. The XFS_GETPARENTS_OFLAG_DONE flag
will be set in gp_flags when there are no more parent pointers to
be read. The below code is an example of XFS_IOC_GETPARENTS
usage:
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <xfs/linux.h>
#include <xfs/xfs.h>
#include <xfs/xfs_types.h>
#include <xfs/xfs_fs.h>
int main() {
struct xfs_getparents gp = { };
struct xfs_getparents_rec *gpr;
int error, fd;
gp.gp_buffer = (uintptr_t)malloc(65536);
if (!gp.gp_buffer) {
perror("malloc");
return 1;
}
gp->gp_bufsize = 65536;
fd = open("/mnt/test/foo.txt", O_RDONLY | O_CREAT);
if (fd == -1)
return errno;
do {
error = ioctl(fd, XFS_IOC_GETPARENTS, gp);
if (error)
return error;
for (gpr = xfs_getparents_first_rec(&gp);
gpr != NULL;
gpr = xfs_getparents_next_rec(&gp, gpr)) {
if (gpr->gpr_name[0] == 0)
break;
printf("inode = %llu\n",
gpr->gpr_parent.ha_fid.fid_ino);
printf("generation = %u\n",
gpr->gpr_parent.ha_fid.fid_gen);
printf("name = \"%s\"\n\n",
gpr->gpr_name);
}
} while (!(gp.gp_flags & XFS_GETPARENTS_OFLAG_DONE));
return 0;
}
On error, -1 is returned, and errno is set to indicate the error.
Error codes can be one of, but are not limited to, the following:
EFSBADCRC
Metadata checksum validation failed while performing the
query.
EFSCORRUPTED
Metadata corruption was encountered while performing the
query.
EINVAL One or more of the arguments specified is invalid.
EMSGSIZE
The record buffer was not large enough to store even a
single record.
ENOMEM Not enough memory to retrieve parent pointers.
EOPNOTSUPP
Repairs of the requested metadata object are not supported.
EROFS Filesystem is read-only and a repair was requested.
ESHUTDOWN
Filesystem is shut down due to previous errors.
EIO An I/O error was encountered while performing the query.
This API is specific to XFS filesystem on the Linux kernel.
ioctl(2)
This page is part of the xfsprogs (utilities for XFS filesystems)
project. Information about the project can be found at
⟨http://xfs.org/⟩. If you have a bug report for this manual page,
send it to linux-xfs@vger.kernel.org. This page was obtained from
the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
2025-02-02. (At that time, the date of the most recent commit
that was found in the repository was 2024-12-02.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to man-pages@man7.org
XFS 2024-04-09 IOCTL-XFS-GETPARENTS(2)
Copyright and license for this manual page
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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