[PATCH 2/9] libxfs: break out the fsop geometry manpage

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Break out the fs geometry ioctl into a separate manpage so that we can
document how it works.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 man/man2/ioctl_xfs_fsop_geometry.2 |  214 ++++++++++++++++++++++++++++++++++++
 man/man3/xfsctl.3                  |   11 +-
 2 files changed, 221 insertions(+), 4 deletions(-)
 create mode 100644 man/man2/ioctl_xfs_fsop_geometry.2


diff --git a/man/man2/ioctl_xfs_fsop_geometry.2 b/man/man2/ioctl_xfs_fsop_geometry.2
new file mode 100644
index 00000000..4045e03b
--- /dev/null
+++ b/man/man2/ioctl_xfs_fsop_geometry.2
@@ -0,0 +1,214 @@
+.\" Copyright (c) 2019, Oracle.  All rights reserved.
+.\"
+.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
+.\" SPDX-License-Identifier: GPL-2.0+
+.\" %%%LICENSE_END
+.TH IOCTL-XFS-FSOP-GEOMETRY 2 2019-04-11 "XFS"
+.SH NAME
+ioctl_xfs_fsop_geometry \- report XFS filesystem shape
+.SH SYNOPSIS
+.br
+.B #include <xfs/xfs_fs.h>
+.PP
+.BI "int ioctl(int " fd ", XFS_IOC_FSOP_GEOMETRY, struct xfs_fsop_geometry *" arg );
+.PP
+.BI "int ioctl(int " fd ", XFS_IOC_FSOP_GEOMETRY_V1, struct xfs_fsop_geometry_v1 *" arg );
+.SH DESCRIPTION
+Report the storage space parameters that influence allocation decisions in
+this XFS filesystem.
+This information is conveyed in a structure of the following form:
+.PP
+.in +4n
+.nf
+struct xfs_fsop_geom {
+	__u32         blocksize;
+	__u32         rtextsize;
+	__u32         agblocks;
+	__u32         agcount;
+	__u32         logblocks;
+	__u32         sectsize;
+	__u32         inodesize;
+	__u32         imaxpct;
+	__u64         datablocks;
+	__u64         rtblocks;
+	__u64         rtextents;
+	__u64         logstart;
+	unsigned char uuid[16];
+	__u32         sunit;
+	__u32         swidth;
+	__s32         version;
+	__u32         flags;
+	__u32         logsectsize;
+	__u32         rtsectsize;
+	__u32         dirblocksize;
+	/* struct xfs_fsop_geom_v1 stops here. */
+
+	__u32         logsunit;
+};
+.fi
+.in
+.PP
+.I blocksize
+is the size of a fundamental filesystem block, in bytes.
+.PP
+.I rtextsize
+is the size of an extent on the realtime volume, in bytes.
+.PP
+.I agblocks
+is the size of an allocation group, in units of filesystem blocks.
+.PP
+.I agcount
+is the number of allocation groups in the filesystem.
+.PP
+.I logblocks
+is the size of the log, in units of filesystem blocks.
+.PP
+.I sectsize
+is the smallest amount of data that can be written to the data device
+atomically, in bytes.
+.PP
+.I inodesize
+is the size of an inode record, in bytes.
+.PP
+.I imaxpct
+is the maximum percentage of the filesystem that can be allocated to inode
+record blocks.
+.PP
+.I datablocks
+is the size of the data device, in units of filesystem blocks.
+.PP
+.I rtblocks
+is the size of the realtime device, in units of filesystem blocks.
+.PP
+.I rtextents
+is the number of extents that can be allocated on the realtime device.
+This ought to be
+.RB "( " rtblocks " * " blocksize " ) / " rtextsize .
+.PP
+.I logstart
+tells the start of the log, in units of filesystem blocks.
+If the filesystem has an external log, this will be zero.
+.PP
+.I uuid
+is the universal unique identifier of the filesystem.
+.PP
+.I sunit
+is what the filesystem has been told is the size of a RAID stripe unit on the
+underlying data device, in filesystem blocks.
+.PP
+.I swidth
+is what the filesystem has been told is the width of a RAID stripe on the
+underlying data device, in units of RAID stripe units.
+.PP
+.I version
+is the version of this structure.
+This value will be XFS_FSOP_GEOM_VERSION.
+.PP
+.I flags
+tell us what features are enabled on the filesystem.
+This field can be any combination of the following:
+.RS 0.4i
+.TP
+.B XFS_FSOP_GEOM_FLAGS_ATTR
+Extended attributes are present.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_NLINK
+This filesystem supports up to 2^32 links.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_QUOTA
+Quotas are enabled.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_IALIGN
+Inodes are aligned for better performance.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_DALIGN
+Data blocks are aligned for better performance.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_SHARED
+Unused.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_EXTFLG
+Filesystem supports unwritten extents.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_DIRV2
+Directories maintain free space data for better performance.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_LOGV2
+Log uses the V2 format.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_SECTOR
+The log device has a sector size larger than 512 bytes.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_ATTR2
+Filesystem contains V2 extended attributes.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_PROJID32
+Project IDs can be as large as 2^32.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_DIRV2CI
+Case-insensitive lookups are supported on directories.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_LAZYSB
+On-disk superblock counters are updated only at unmount time.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_V5SB
+Metadata blocks are self describing and contain checksums.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_FTYPE
+Directories cache inode types in directory entries.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_FINOBT
+Filesystem maintains an index of free inodes.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_SPINODES
+Filesystem tries harder to allocate inodes when free space is fragmented.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_RMAPBT
+Filesystem stores reverse mappings of blocks to owners.
+.TP
+.B XFS_FSOP_GEOM_FLAGS_REFLINK
+Filesystem supports sharing blocks.
+.RE
+
+.PD 1
+.PP
+.I logsectsize
+is the smallest amount of data that can be written to the log device atomically,
+in bytes.
+.PP
+.I rtsectsize
+is the smallest amount of data that can be written to the realtime device
+atomically, in bytes.
+.PP
+.I dirblocksize
+is the size of directory blocks, in bytes.
+.PP
+.I logsunit
+is what the filesystem has been told is the size of a RAID stripe unit on the
+underlying log device, in filesystem blocks.
+This field is meaningful only if the flag
+.B  XFS_FSOP_GEOM_FLAGS_LOGV2
+is set.
+.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 EIO
+An I/O error was encountered while performing 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 2992b5be..1237eac6 100644
--- a/man/man3/xfsctl.3
+++ b/man/man3/xfsctl.3
@@ -479,6 +479,12 @@ the kernel, except no output count parameter is used (should
 be initialized to zero).
 An error is returned if the inode number is invalid.
 
+.TP
+.B XFS_IOC_FSGEOMETRY
+See
+.BR ioctl_xfs_fsop_geometry (2)
+for more information.
+
 .PP
 .nf
 .B XFS_IOC_THAW
@@ -494,10 +500,6 @@ An error is returned if the inode number is invalid.
 These interfaces are used to implement various filesystem internal
 operations on XFS filesystems.
 For
-.B XFS_IOC_FSGEOMETRY
-(get filesystem mkfs time information), the output structure is of type
-.BR struct xfs_fsop_geom .
-For
 .B XFS_FS_COUNTS
 (get filesystem dynamic global information), the output structure is of type
 .BR xfs_fsop_counts_t .
@@ -506,6 +508,7 @@ as they are not of general use to applications.
 
 .SH SEE ALSO
 .BR ioctl_xfs_fsgetxattr (2),
+.BR ioctl_xfs_fsop_geometry (2),
 .BR fstatfs (2),
 .BR statfs (2),
 .BR xfs (5),