Handle ECKSUM as new EZFS_CKSUM ‒ "insufficient replicas"

[nabijaczleweli]

Motivation and Context

#13808

How Has This Been Tested?

Given:

diff --git a/lib/libzfs/libzfs_pool.c b/lib/libzfs/libzfs_pool.c
index eea388cf3..717e9a94c 100644
--- a/lib/libzfs/libzfs_pool.c
+++ b/lib/libzfs/libzfs_pool.c
@@ -2053,6 +2053,7 @@ zpool_import_props(libzfs_handle_t *hdl, nvlist_t *config, const char *newname,
                zcmd_expand_dst_nvlist(hdl, &zc);
        if (ret != 0)
                error = errno;
+       error = errno = ECKSUM;

        (void) zcmd_read_dst_nvlist(hdl, &zc, &nv);

I got

# ./zpool import -d /tmp pl
cannot import 'pl': insufficient replicas
        Destroy and re-create the pool from
        a backup source.

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)
• 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. – none apply(?)
• I have run the ZFS Test Suite with this change applied. – Ci take my hand
• All commit messages are properly formatted and contain Signed-off-by.

[ryao]

This also closes #6805. That said, this looks good to me. Feel free to add my reviewed-by.

[nabijaczleweli]

My first thought was to make it

typedef enum zfs_error {
	EZFS_SUCCESS = 0,	/* no error -- success */
	EZFS_CKSUM = ECKSUM,		/* insufficient replicas */
	EZFS_NOMEM = 2000,	/* out of memory */

and I think that's better but idk if that's valid ideologically, esp. given that that's EINTEGRITY=97 on FreeBSD vs EBADE=52 under Linux?

[ryao]

My first thought was to make it

typedef enum zfs_error {
	EZFS_SUCCESS = 0,	/* no error -- success */
	EZFS_CKSUM = ECKSUM,		/* insufficient replicas */
	EZFS_NOMEM = 2000,	/* out of memory */

and I think that's better but idk if that's valid ideologically, esp. given that that's EINTEGRITY=97 on FreeBSD vs EBADE=52 under Linux?

It is fine the way you did it. The values of zfs_error do not need to match the system error code values.