{
  "slug": "ijournaling",
  "term": "iJournaling",
  "aliases": [],
  "definition": "iJournaling is a research ext4 journaling design that commits file-related metadata on fsync while retaining periodic compound transactions.",
  "note": "Separate per-core journals reduce unrelated commit dependencies; recovery reconstructs shared metadata. Directory fsync and uncommitted hard-link changes use normal journaling. [ijournaling]\n\nFastCommit's ATC 2024 comparison questions compatibility with applications relying on incidental persistence of other files. It did not benchmark iJournaling because the code was unavailable to its authors. [fastcommit]\n\nThe Linux fsync contract concerns the referenced file, not every previously modified file; directory-entry durability requires separate attention. [fsync]\n\nThe FAST 2025 DJFS study later evaluated an iJournaling port over CXL.mem on a CMM-H prototype, not the unchanged 2017 implementation. Code unavailable to one study's authors is a time-scoped statement, not proof of permanent unavailability. [djfs]",
  "status": "research",
  "advantages": [],
  "limitations": [],
  "related": [
    "ext4-fast-commit",
    "physical-journaling"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-14",
  "citations": [
    {
      "id": "ijournaling",
      "title": "Park and Shin. iJournaling. USENIX ATC 2017, pp.787-798; sections 5.1-5.3 and 6.4.",
      "url": "https://www.usenix.org/system/files/conference/atc17/atc17-park.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "fastcommit",
      "title": "Shirwadkar, Kadekodi and Tso. FastCommit. USENIX ATC 2024, section 3 and section 4 footnote 4, pp.159-160.",
      "url": "https://www.usenix.org/system/files/atc24-shirwadkar.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "fsync",
      "title": "Linux man-pages 6.19: fsync(2), file and directory synchronization.",
      "url": "https://man7.org/linux/man-pages/man2/fsync.2.html",
      "accessed": "2026-11-13"
    },
    {
      "id": "djfs",
      "title": "Yoo et al. DJFS: Directory-Granularity Filesystem Journaling for CMM-H SSDs. FAST 2025, section 7.1, printed p.45.",
      "url": "https://www.usenix.org/system/files/fast25-yoo.pdf",
      "accessed": "2026-11-14"
    }
  ],
  "provenance": [
    "Historical source synthesis, not a prototype execution, performance replication or claim of stock-kernel support.",
    "The companion article compares published block-count descriptions without treating the proposed single-block optimization as measured."
  ]
}