ext4 filesystems during 'rear recover'¶

sebastian-koehler opened issue at 2026-10-04 16:05:¶

Summary¶

Adds MKFS_EXT_OPTIONS, mirroring the existing MKFS_XFS_OPTIONS, so a user can pass extra mkfs/mke2fs options (e.g. -E nodiscard) for ext2/ext3/ext4 filesystems via local.conf/site.conf during rear recover.
Motivating case: mke2fs's default block-discard/TRIM pass is slow against thin-provisioned virtual disks, the same problem MKFS_XFS_OPTIONS="-K" already solves for XFS.
One flat global variable, no per-device override: the (ext*) case arm in 131_include_filesystem_code.sh is shared by ext2/ext3/ext4 with no per-fstype branching, and unlike XFS there is no saved-raw-options replay tier for a per-device override to take precedence over, so that extra complexity isn't warranted here.

Changes¶

usr/share/rear/layout/prepare/GNU/Linux/131_include_filesystem_code.sh: reads MKFS_EXT_OPTIONS and appends it to the generated mkfs command in both the -U uuid branch (and its no--U-support fallback) and the no-uuid branch.
usr/share/rear/conf/default.conf: new documentation block for MKFS_EXT_OPTIONS, placed directly after the existing MKFS_XFS_OPTIONS block and matching its style.

Test plan¶

☒ bash -n syntax check on the modified script.
☒ Sourced create_fs() directly with stubbed Log/LogPrint/mount_fs and a synthetic disklayout.conf ext4 entry; confirmed the generated mkfs line is byte-identical to before this change when MKFS_EXT_OPTIONS is unset, and correctly includes -E nodiscard right before -U/-F in all three code paths (uuid branch, its fallback, and the no-uuid branch) when set.
☐ End-to-end rear mkbackup/rear recover on a live ext4 client with MKFS_EXT_OPTIONS="-E nodiscard" set.

codacy-production commented at 2026-10-04 16:06:¶

Up to standards ✅¶

🟢 Issues 0 issues

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[Export of Github issue for rear/rear.]

#3650 PR closed: Add MKFS_EXT_OPTIONS for ext2/ext3/ext4 filesystems during 'rear recover'¶