diff mbox series

[5/9] libxfs: break out the INUMBERS manpage

Message ID 155993577237.2343530.1326868231083603392.stgit@magnolia (mailing list archive)
State New, archived
Headers show
Series xfsprogs: document the ioctls scrub uses | expand

Commit Message

Darrick J. Wong June 7, 2019, 7:29 p.m. UTC 
From: Darrick J. Wong <darrick.wong@oracle.com>

Create a separate manual page for the INUMBERS ioctl so we can document
how it works.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 man/man2/ioctl_xfs_fsinumbers.2 |  115 +++++++++++++++++++++++++++++++++++++++
 man/man3/xfsctl.3               |   34 +-----------
 2 files changed, 119 insertions(+), 30 deletions(-)
 create mode 100644 man/man2/ioctl_xfs_fsinumbers.2

Comments

Eric Sandeen June 17, 2019, 4:34 p.m. UTC | #1 
On 6/7/19 2:29 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Create a separate manual page for the INUMBERS ioctl so we can document
> how it works.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  man/man2/ioctl_xfs_fsinumbers.2 |  115 +++++++++++++++++++++++++++++++++++++++
>  man/man3/xfsctl.3               |   34 +-----------
>  2 files changed, 119 insertions(+), 30 deletions(-)
>  create mode 100644 man/man2/ioctl_xfs_fsinumbers.2
> 
> 
> diff --git a/man/man2/ioctl_xfs_fsinumbers.2 b/man/man2/ioctl_xfs_fsinumbers.2
> new file mode 100644
> index 00000000..86cdf4d9
> --- /dev/null
> +++ b/man/man2/ioctl_xfs_fsinumbers.2
> @@ -0,0 +1,115 @@
> +.\" Copyright (c) 2019, Oracle.  All rights reserved.
> +.\"
> +.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
> +.\" SPDX-License-Identifier: GPL-2.0+
> +.\" %%%LICENSE_END
> +.TH IOCTL-XFS-FSINUMBERS 2 2019-04-16 "XFS"
> +.SH NAME
> +ioctl_xfs_fsinumbers \- extract a list of valid inode numbers from an XFS filesystem
> +.SH SYNOPSIS
> +.br
> +.B #include <xfs/xfs_fs.h>
> +.PP
> +.BI "int ioctl(int " fd ", XFS_IOC_FSINUMBERS, struct xfs_fsop_bulkreq *" arg );
> +.SH DESCRIPTION
> +Query a list of valid inode numbers from an XFS filesystem.
> +It is intended to be called iteratively to obtain the entire set of inodes.
> +These ioctls use
> +.B struct xfs_fsop_bulkreq
> +to set up a bulk transfer with the kernel:
> +.PP
> +.in +4n
> +.nf
> +struct xfs_fsop_bulkreq {
> +	__u64   *lastip;
> +	__s32   count;
> +	void    *ubuffer;
> +	__s32   *ocount;
> +};
> +.fi
> +.in
> +.PP
> +.I lastip
> +points to a value that will receive the number of the "last inode".
> +This should be set to one less than the number of the first inode for which the
> +caller wants information, or zero to start with the first inode in the
> +filesystem.
> +After the call, this value will be set to the number of the last inode for
> +which information is supplied.
> +This field will not be updated if
> +.I ocount
> +is NULL.
> +.PP
> +.I count
> +is the number of inodes to examine.

again should it have something like "corresponding to the number
of array elements passed in in the ubuffer array?"

> +.PP
> +.I ocount
> +points to a value that will receive the number of records returned.
> +An output value of zero means that there are no more inodes left to enumerate.
> +If this value is NULL, then neither
> +.I ocount
> +nor
> +.I lastip
> +will be updated.
> +.PP
> +.I ubuffer
> +points to a memory buffer where information will be copied.
> +This buffer must be an array of
> +.B struct xfs_inogrp
> +which is described below.
> +The array must have at least
> +.I count
> +elements.
> +.PP
> +.in +4n
> +.nf
> +struct xfs_inogrp {
> +	__u64   xi_startino;
> +	__s32   xi_alloccount;
> +	__u64   xi_allocmask;
> +}
> +.fi
> +.in
> +.PP
> +.I xi_startino
> +is the number of this inode numbers record.

this phrasing confuses me.

xi_startino is the first inode number in this inode... group?

> +Each inode numbers record will correspond roughly to a record in the inode
> +btree, though this is not guaranteed.

I don't think that is useful information.

> +.PP
> +.I xi_alloccount
> +is the number of bits that are set in
> +.IR xi_allocmask .

i.e. the number of inodes in use in this group?

> +.PP
> +.I xi_allocmask
> +is the mask of inodes that are in use for this inode.

inodes that are in use for this inode?  wut.

> +The bitmask is 64 bits long, and the least significant bit corresponds to inode
> +.BR xi_startino .

ok so finally we get to what I consider to be the useful thing that ties it
all together ;)

so maybe best to just say that it returns inode usage information for a group of
64 consecutive inode numbers, starting with inode xi_startino, with a bitmask of
in-use inodes in xi_allocmask, with total in-use inodes for this batch/group/set
shown in xi_alloccount?

> +.SH RETURN VALUE
> +On error, \-1 is returned, and
> +.I errno
> +is set to indicate the error.
> +.PP
> +.SH ERRORS
> +Error codes can be one of, but are not limited to, the following:
> +.TP
> +.B EFAULT
> +The kernel was not able to copy into the userspace buffer.
> +.TP
> +.B EFSBADCRC
> +Metadata checksum validation failed while performing the query.
> +.TP
> +.B EFSCORRUPTED
> +Metadata corruption was encountered while performing the query.
> +.TP
> +.B EINVAL
> +One of the arguments was not valid.
> +.TP
> +.B EIO
> +An I/O error was encountered while performing the query.
> +.TP
> +.B ENOMEM
> +There was insufficient memory to perform the query.
> +.SH CONFORMING TO
> +This API is specific to XFS filesystem on the Linux kernel.
> +.SH SEE ALSO
> +.BR ioctl (2)
> diff --git a/man/man3/xfsctl.3 b/man/man3/xfsctl.3
> index cdf0fcfc..148119a9 100644
> --- a/man/man3/xfsctl.3
> +++ b/man/man3/xfsctl.3
> @@ -368,36 +368,9 @@ can be any open file in the XFS filesystem in question.
>  .PP
>  .TP
>  .B XFS_IOC_FSINUMBERS
> -This interface is used to extract a list of valid inode numbers from an
> -XFS filesystem.
> -It is intended to be called iteratively, to obtain the entire set of inodes.
> -The information is passed in and out via a structure of type
> -.B xfs_fsop_bulkreq_t
> -pointed to by the final argument.
> -.B lastip
> -is a pointer to a variable containing the last inode number returned,
> -initially it should be zero.
> -.B icount
> -is the size of the array of structures specified by
> -.BR ubuffer .
> -.B ubuffer
> -is the address of an array of structures, of type
> -.BR xfs_inogrp_t .
> -This structure has the following elements:
> -.B xi_startino
> -(starting inode number),
> -.B xi_alloccount
> -(count of bits set in xi_allocmask), and
> -.B xi_allocmask
> -(mask of allocated inodes in this group).
> -The bitmask is 64 bits long, and the least significant bit corresponds to inode
> -.B xi_startino.
> -Each bit is set if the corresponding inode is in use.
> -.B ocount
> -is a pointer to a count of returned values, filled in by the call.
> -An output
> -.B ocount
> -value of zero means that the inode table has been exhausted.
> +See
> +.BR ioctl_xfs_fsinumbers (2)
> +for more information.
>  
>  .TP
>  .B XFS_IOC_FSGEOMETRY
> @@ -442,6 +415,7 @@ as they are not of general use to applications.
>  .BR ioctl_xfs_fsgetxattr (2),
>  .BR ioctl_xfs_fsop_geometry (2),
>  .BR ioctl_xfs_fsbulkstat (2),
> +.BR ioctl_xfs_fsinumbers (2),
>  .BR fstatfs (2),
>  .BR statfs (2),
>  .BR xfs (5),
>
Darrick J. Wong June 18, 2019, 7:38 p.m. UTC | #2 
On Mon, Jun 17, 2019 at 11:34:00AM -0500, Eric Sandeen wrote:
> 
> 
> On 6/7/19 2:29 PM, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Create a separate manual page for the INUMBERS ioctl so we can document
> > how it works.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  man/man2/ioctl_xfs_fsinumbers.2 |  115 +++++++++++++++++++++++++++++++++++++++
> >  man/man3/xfsctl.3               |   34 +-----------
> >  2 files changed, 119 insertions(+), 30 deletions(-)
> >  create mode 100644 man/man2/ioctl_xfs_fsinumbers.2
> > 
> > 
> > diff --git a/man/man2/ioctl_xfs_fsinumbers.2 b/man/man2/ioctl_xfs_fsinumbers.2
> > new file mode 100644
> > index 00000000..86cdf4d9
> > --- /dev/null
> > +++ b/man/man2/ioctl_xfs_fsinumbers.2
> > @@ -0,0 +1,115 @@
> > +.\" Copyright (c) 2019, Oracle.  All rights reserved.
> > +.\"
> > +.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
> > +.\" SPDX-License-Identifier: GPL-2.0+
> > +.\" %%%LICENSE_END
> > +.TH IOCTL-XFS-FSINUMBERS 2 2019-04-16 "XFS"
> > +.SH NAME
> > +ioctl_xfs_fsinumbers \- extract a list of valid inode numbers from an XFS filesystem
> > +.SH SYNOPSIS
> > +.br
> > +.B #include <xfs/xfs_fs.h>
> > +.PP
> > +.BI "int ioctl(int " fd ", XFS_IOC_FSINUMBERS, struct xfs_fsop_bulkreq *" arg );
> > +.SH DESCRIPTION
> > +Query a list of valid inode numbers from an XFS filesystem.
> > +It is intended to be called iteratively to obtain the entire set of inodes.
> > +These ioctls use
> > +.B struct xfs_fsop_bulkreq
> > +to set up a bulk transfer with the kernel:
> > +.PP
> > +.in +4n
> > +.nf
> > +struct xfs_fsop_bulkreq {
> > +	__u64   *lastip;
> > +	__s32   count;
> > +	void    *ubuffer;
> > +	__s32   *ocount;
> > +};
> > +.fi
> > +.in
> > +.PP
> > +.I lastip
> > +points to a value that will receive the number of the "last inode".
> > +This should be set to one less than the number of the first inode for which the
> > +caller wants information, or zero to start with the first inode in the
> > +filesystem.
> > +After the call, this value will be set to the number of the last inode for
> > +which information is supplied.
> > +This field will not be updated if
> > +.I ocount
> > +is NULL.
> > +.PP
> > +.I count
> > +is the number of inodes to examine.
> 
> again should it have something like "corresponding to the number
> of array elements passed in in the ubuffer array?"

Fixed.

> > +.PP
> > +.I ocount
> > +points to a value that will receive the number of records returned.
> > +An output value of zero means that there are no more inodes left to enumerate.
> > +If this value is NULL, then neither
> > +.I ocount
> > +nor
> > +.I lastip
> > +will be updated.
> > +.PP
> > +.I ubuffer
> > +points to a memory buffer where information will be copied.
> > +This buffer must be an array of
> > +.B struct xfs_inogrp
> > +which is described below.
> > +The array must have at least
> > +.I count
> > +elements.
> > +.PP
> > +.in +4n
> > +.nf
> > +struct xfs_inogrp {
> > +	__u64   xi_startino;
> > +	__s32   xi_alloccount;
> > +	__u64   xi_allocmask;
> > +}
> > +.fi
> > +.in
> > +.PP
> > +.I xi_startino
> > +is the number of this inode numbers record.
> 
> this phrasing confuses me.
> 
> xi_startino is the first inode number in this inode... group?

Yes, will chnage it to that.

> > +Each inode numbers record will correspond roughly to a record in the inode
> > +btree, though this is not guaranteed.
> 
> I don't think that is useful information.

Ok.

> > +.PP
> > +.I xi_alloccount
> > +is the number of bits that are set in
> > +.IR xi_allocmask .
> 
> i.e. the number of inodes in use in this group?

Yes.  I'll add a second sentence stating this.

> > +.PP
> > +.I xi_allocmask
> > +is the mask of inodes that are in use for this inode.
> 
> inodes that are in use for this inode?  wut.

Yeah, is dumb.

"is a bitmask of inodes that are allocated in this inode group."

> > +The bitmask is 64 bits long, and the least significant bit corresponds to inode
> > +.BR xi_startino .
> 
> ok so finally we get to what I consider to be the useful thing that ties it
> all together ;)
> 
> so maybe best to just say that it returns inode usage information for a group of
> 64 consecutive inode numbers, starting with inode xi_startino, with a bitmask of
> in-use inodes in xi_allocmask, with total in-use inodes for this batch/group/set
> shown in xi_alloccount?

Yep.  I'll try to clarify this more in the manpage.

--D

> 
> > +.SH RETURN VALUE
> > +On error, \-1 is returned, and
> > +.I errno
> > +is set to indicate the error.
> > +.PP
> > +.SH ERRORS
> > +Error codes can be one of, but are not limited to, the following:
> > +.TP
> > +.B EFAULT
> > +The kernel was not able to copy into the userspace buffer.
> > +.TP
> > +.B EFSBADCRC
> > +Metadata checksum validation failed while performing the query.
> > +.TP
> > +.B EFSCORRUPTED
> > +Metadata corruption was encountered while performing the query.
> > +.TP
> > +.B EINVAL
> > +One of the arguments was not valid.
> > +.TP
> > +.B EIO
> > +An I/O error was encountered while performing the query.
> > +.TP
> > +.B ENOMEM
> > +There was insufficient memory to perform the query.
> > +.SH CONFORMING TO
> > +This API is specific to XFS filesystem on the Linux kernel.
> > +.SH SEE ALSO
> > +.BR ioctl (2)
> > diff --git a/man/man3/xfsctl.3 b/man/man3/xfsctl.3
> > index cdf0fcfc..148119a9 100644
> > --- a/man/man3/xfsctl.3
> > +++ b/man/man3/xfsctl.3
> > @@ -368,36 +368,9 @@ can be any open file in the XFS filesystem in question.
> >  .PP
> >  .TP
> >  .B XFS_IOC_FSINUMBERS
> > -This interface is used to extract a list of valid inode numbers from an
> > -XFS filesystem.
> > -It is intended to be called iteratively, to obtain the entire set of inodes.
> > -The information is passed in and out via a structure of type
> > -.B xfs_fsop_bulkreq_t
> > -pointed to by the final argument.
> > -.B lastip
> > -is a pointer to a variable containing the last inode number returned,
> > -initially it should be zero.
> > -.B icount
> > -is the size of the array of structures specified by
> > -.BR ubuffer .
> > -.B ubuffer
> > -is the address of an array of structures, of type
> > -.BR xfs_inogrp_t .
> > -This structure has the following elements:
> > -.B xi_startino
> > -(starting inode number),
> > -.B xi_alloccount
> > -(count of bits set in xi_allocmask), and
> > -.B xi_allocmask
> > -(mask of allocated inodes in this group).
> > -The bitmask is 64 bits long, and the least significant bit corresponds to inode
> > -.B xi_startino.
> > -Each bit is set if the corresponding inode is in use.
> > -.B ocount
> > -is a pointer to a count of returned values, filled in by the call.
> > -An output
> > -.B ocount
> > -value of zero means that the inode table has been exhausted.
> > +See
> > +.BR ioctl_xfs_fsinumbers (2)
> > +for more information.
> >  
> >  .TP
> >  .B XFS_IOC_FSGEOMETRY
> > @@ -442,6 +415,7 @@ as they are not of general use to applications.
> >  .BR ioctl_xfs_fsgetxattr (2),
> >  .BR ioctl_xfs_fsop_geometry (2),
> >  .BR ioctl_xfs_fsbulkstat (2),
> > +.BR ioctl_xfs_fsinumbers (2),
> >  .BR fstatfs (2),
> >  .BR statfs (2),
> >  .BR xfs (5),
> >
diff mbox series

Patch

diff --git a/man/man2/ioctl_xfs_fsinumbers.2 b/man/man2/ioctl_xfs_fsinumbers.2
new file mode 100644
index 00000000..86cdf4d9
--- /dev/null
+++ b/man/man2/ioctl_xfs_fsinumbers.2
@@ -0,0 +1,115 @@ 
+.\" Copyright (c) 2019, Oracle.  All rights reserved.
+.\"
+.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
+.\" SPDX-License-Identifier: GPL-2.0+
+.\" %%%LICENSE_END
+.TH IOCTL-XFS-FSINUMBERS 2 2019-04-16 "XFS"
+.SH NAME
+ioctl_xfs_fsinumbers \- extract a list of valid inode numbers from an XFS filesystem
+.SH SYNOPSIS
+.br
+.B #include <xfs/xfs_fs.h>
+.PP
+.BI "int ioctl(int " fd ", XFS_IOC_FSINUMBERS, struct xfs_fsop_bulkreq *" arg );
+.SH DESCRIPTION
+Query a list of valid inode numbers from an XFS filesystem.
+It is intended to be called iteratively to obtain the entire set of inodes.
+These ioctls use
+.B struct xfs_fsop_bulkreq
+to set up a bulk transfer with the kernel:
+.PP
+.in +4n
+.nf
+struct xfs_fsop_bulkreq {
+	__u64   *lastip;
+	__s32   count;
+	void    *ubuffer;
+	__s32   *ocount;
+};
+.fi
+.in
+.PP
+.I lastip
+points to a value that will receive the number of the "last inode".
+This should be set to one less than the number of the first inode for which the
+caller wants information, or zero to start with the first inode in the
+filesystem.
+After the call, this value will be set to the number of the last inode for
+which information is supplied.
+This field will not be updated if
+.I ocount
+is NULL.
+.PP
+.I count
+is the number of inodes to examine.
+.PP
+.I ocount
+points to a value that will receive the number of records returned.
+An output value of zero means that there are no more inodes left to enumerate.
+If this value is NULL, then neither
+.I ocount
+nor
+.I lastip
+will be updated.
+.PP
+.I ubuffer
+points to a memory buffer where information will be copied.
+This buffer must be an array of
+.B struct xfs_inogrp
+which is described below.
+The array must have at least
+.I count
+elements.
+.PP
+.in +4n
+.nf
+struct xfs_inogrp {
+	__u64   xi_startino;
+	__s32   xi_alloccount;
+	__u64   xi_allocmask;
+}
+.fi
+.in
+.PP
+.I xi_startino
+is the number of this inode numbers record.
+Each inode numbers record will correspond roughly to a record in the inode
+btree, though this is not guaranteed.
+.PP
+.I xi_alloccount
+is the number of bits that are set in
+.IR xi_allocmask .
+.PP
+.I xi_allocmask
+is the mask of inodes that are in use for this inode.
+The bitmask is 64 bits long, and the least significant bit corresponds to inode
+.BR xi_startino .
+.SH RETURN VALUE
+On error, \-1 is returned, and
+.I errno
+is set to indicate the error.
+.PP
+.SH ERRORS
+Error codes can be one of, but are not limited to, the following:
+.TP
+.B EFAULT
+The kernel was not able to copy into the userspace buffer.
+.TP
+.B EFSBADCRC
+Metadata checksum validation failed while performing the query.
+.TP
+.B EFSCORRUPTED
+Metadata corruption was encountered while performing the query.
+.TP
+.B EINVAL
+One of the arguments was not valid.
+.TP
+.B EIO
+An I/O error was encountered while performing the query.
+.TP
+.B ENOMEM
+There was insufficient memory to perform the query.
+.SH CONFORMING TO
+This API is specific to XFS filesystem on the Linux kernel.
+.SH SEE ALSO
+.BR ioctl (2)
diff --git a/man/man3/xfsctl.3 b/man/man3/xfsctl.3
index cdf0fcfc..148119a9 100644
--- a/man/man3/xfsctl.3
+++ b/man/man3/xfsctl.3
@@ -368,36 +368,9 @@  can be any open file in the XFS filesystem in question.
 .PP
 .TP
 .B XFS_IOC_FSINUMBERS
-This interface is used to extract a list of valid inode numbers from an
-XFS filesystem.
-It is intended to be called iteratively, to obtain the entire set of inodes.
-The information is passed in and out via a structure of type
-.B xfs_fsop_bulkreq_t
-pointed to by the final argument.
-.B lastip
-is a pointer to a variable containing the last inode number returned,
-initially it should be zero.
-.B icount
-is the size of the array of structures specified by
-.BR ubuffer .
-.B ubuffer
-is the address of an array of structures, of type
-.BR xfs_inogrp_t .
-This structure has the following elements:
-.B xi_startino
-(starting inode number),
-.B xi_alloccount
-(count of bits set in xi_allocmask), and
-.B xi_allocmask
-(mask of allocated inodes in this group).
-The bitmask is 64 bits long, and the least significant bit corresponds to inode
-.B xi_startino.
-Each bit is set if the corresponding inode is in use.
-.B ocount
-is a pointer to a count of returned values, filled in by the call.
-An output
-.B ocount
-value of zero means that the inode table has been exhausted.
+See
+.BR ioctl_xfs_fsinumbers (2)
+for more information.
 
 .TP
 .B XFS_IOC_FSGEOMETRY
@@ -442,6 +415,7 @@  as they are not of general use to applications.
 .BR ioctl_xfs_fsgetxattr (2),
 .BR ioctl_xfs_fsop_geometry (2),
 .BR ioctl_xfs_fsbulkstat (2),
+.BR ioctl_xfs_fsinumbers (2),
 .BR fstatfs (2),
 .BR statfs (2),
 .BR xfs (5),