[PATCH] xfs_db: improve the fsmap man page entry

[PATCH] xfs_db: improve the fsmap man page entry

[Christoph Hellwig]

Improve documentation of the flags and optional arguments, and fix up
messed up formatting.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 man/man8/xfs_db.8 | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
index ba2a68211ef2..89db535d38c9 100644
--- a/man/man8/xfs_db.8
+++ b/man/man8/xfs_db.8
@@ -849,14 +849,24 @@ command to convert to and from this form. Block numbers given for file blocks
 .B bmap
 command) are in this form.
 .TP
-.BI "fsmap [ " start " ] [ " end " ]
+.BI "fsmap [\-r] [" start " [" end ]]
 Prints the mapping of disk blocks used by an XFS filesystem.  The map
 lists each extent used by files, allocation group metadata,
 journalling logs, and static filesystem metadata, as well as any
 regions that are unused.  All blocks, offsets, and lengths are specified
 in units of 512-byte blocks, no matter what the filesystem's block size is.
-.BI "The optional " start " and " end " arguments can be used to constrain
-the output to a particular range of disk blocks.
+.IP
+The optional
+.I start
+and
+.I end
+arguments can be used to constrain the output to a particular range of disk
+blocks.
+.IP
+When the
+.B \-r
+option is specified, prints the reverse mapping for the real-time device
+instead of the data device.
 .TP
 .BI "fuzz [\-c] [\-d] " "field action"
 Write garbage into a specific structure field on disk.
-- 
2.53.0

Re: [PATCH] xfs_db: improve the fsmap man page entry

[Darrick J. Wong]

On Mon, Aug 31, 2026 at 10:11:52AM +0300, Christoph Hellwig wrote:
> Improve documentation of the flags and optional arguments, and fix up
> messed up formatting.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

I wonder if it's worth documenting that fsmap -l shows external
log device mappings?

Looks better in any case so
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  man/man8/xfs_db.8 | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8
> index ba2a68211ef2..89db535d38c9 100644
> --- a/man/man8/xfs_db.8
> +++ b/man/man8/xfs_db.8
> @@ -849,14 +849,24 @@ command to convert to and from this form. Block numbers given for file blocks
>  .B bmap
>  command) are in this form.
>  .TP
> -.BI "fsmap [ " start " ] [ " end " ]
> +.BI "fsmap [\-r] [" start " [" end ]]
>  Prints the mapping of disk blocks used by an XFS filesystem.  The map
>  lists each extent used by files, allocation group metadata,
>  journalling logs, and static filesystem metadata, as well as any
>  regions that are unused.  All blocks, offsets, and lengths are specified
>  in units of 512-byte blocks, no matter what the filesystem's block size is.
> -.BI "The optional " start " and " end " arguments can be used to constrain
> -the output to a particular range of disk blocks.
> +.IP
> +The optional
> +.I start
> +and
> +.I end
> +arguments can be used to constrain the output to a particular range of disk
> +blocks.
> +.IP
> +When the
> +.B \-r
> +option is specified, prints the reverse mapping for the real-time device
> +instead of the data device.
>  .TP
>  .BI "fuzz [\-c] [\-d] " "field action"
>  Write garbage into a specific structure field on disk.
> -- 
> 2.53.0
> 
> 

Re: [PATCH] xfs_db: improve the fsmap man page entry

[Christoph Hellwig]

On Mon, Aug 31, 2026 at 07:46:04AM -0700, Darrick J. Wong wrote:
> On Mon, Aug 31, 2026 at 10:11:52AM +0300, Christoph Hellwig wrote:
> > Improve documentation of the flags and optional arguments, and fix up
> > messed up formatting.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> I wonder if it's worth documenting that fsmap -l shows external
> log device mappings?

That would be a bad idea, because it doesn't actually support that
option (in for-next at least).

Re: [PATCH] xfs_db: improve the fsmap man page entry

[Darrick J. Wong]

On Tue, Sep 01, 2026 at 10:08:50AM +0200, Christoph Hellwig wrote:
> On Mon, Aug 31, 2026 at 07:46:04AM -0700, Darrick J. Wong wrote:
> > On Mon, Aug 31, 2026 at 10:11:52AM +0300, Christoph Hellwig wrote:
> > > Improve documentation of the flags and optional arguments, and fix up
> > > messed up formatting.
> > > 
> > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > 
> > I wonder if it's worth documenting that fsmap -l shows external
> > log device mappings?
> 
> That would be a bad idea, because it doesn't actually support that
> option (in for-next at least).

Oh, whoops.  That question only makes sense to the xfs_io fsmap command,
not xfs_db.  Stupid question withdrawn. :)

--D