Add --file-layout (-f) option to zdb(8) to display the

[kithrup]

raidz file layout for a given file. This leverages the internal vdev_raidz_map_alloc() function to find the map of how the block data is laid out across the child disks.

The column entry for each row looks like:
+------------+
| D2 43 |
| 6020da |
+------------+
representing here the logical data column 2 that is 43 sectors high
starting at sector 0x6020da.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: sean.fagan@klarasystems.com

Motivation and Context

This shows the layout of objects in a RAIDZ set. This was required to examine some data corruption.

Description

This leverages the internal vdev_raidz_map_alloc() function to find the map of how the block data is laid out across the child disks.

This is a re-creation of #16835

How Has This Been Tested?

I've run the ZFS tests for zdb, and I've run this particular command (zdb -f pool/ objid) for various pool layouts and object IDs.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Quality assurance (non-breaking change which makes the code more robust against bugs)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• [] I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.