{
  "slug": "ext4-fast-commit",
  "term": "Ext4 fast commit",
  "aliases": [
    "Ext4 fast-commit journaling"
  ],
  "definition": "Ext4 fast commit is a journaling mechanism that records metadata deltas for eligible updates instead of a full traditional metadata-block commit.",
  "note": "Linux v6.12 describes this for ordered mode, with fallback to full commits. [journal] Replay targets recorded outcomes rather than blindly repeating procedures; the implementation also documents hardening work, so the design rationale is not a correctness certification. [fast] See the explicitly synthetic interrupted-recovery model. [hesela]",
  "status": "shipping",
  "advantages": [],
  "limitations": [
    {
      "text": "The cited Linux v6.12 mechanism and explanatory model do not certify a deployed kernel or storage stack.",
      "citationIds": [
        "hesela"
      ]
    }
  ],
  "related": [
    "journal-checkpoint",
    "journal-revoke-record",
    "crash-consistency",
    "persistence-ordering"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "journal",
      "title": "Linux v6.12: ext4 Journal (jbd2), layout and fast commits",
      "url": "https://github.com/torvalds/linux/blob/v6.12/Documentation/filesystems/ext4/journal.rst",
      "accessed": "2026-10-14"
    },
    {
      "id": "fast",
      "title": "Linux v6.12: fs/ext4/fast_commit.c, replay idempotence and stated limitations",
      "url": "https://github.com/torvalds/linux/blob/v6.12/fs/ext4/fast_commit.c",
      "accessed": "2026-10-14"
    },
    {
      "id": "hesela",
      "title": "Hesela: Ext4 journal replay, revocation and repeatable recovery",
      "url": "https://hesela.com/analyses/ext4-journal-replay-revocation/",
      "accessed": "2026-10-14"
    }
  ],
  "updated": "2026-10-14"
}