{
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-21",
  "slug": "f2fs-segment-summary-area",
  "term": "F2FS Segment Summary Area",
  "aliases": [
    "F2FS SSA"
  ],
  "definition": "The F2FS Segment Summary Area stores ownership information for blocks in the filesystem's main area.",
  "note": "The Linux v6.12 summary format uses the direct-node ID for a data block and the node's own ID for a node block. Data summaries also identify the offset of the data-block address within its node; the entry interpretation depends on the block type. [format612]\n\nThis ownership direction differs from NAT's node-ID-to-location lookup and SIT's validity bookkeeping. These structures answer different questions during cleaning; none is a backup of the user payload. [manual]",
  "related": [
    "f2fs",
    "f2fs-node-address-table",
    "f2fs-segment-information-table",
    "garbage-collection-host"
  ],
  "citations": [
    {
      "id": "format612",
      "title": "Linux v6.12 include/linux/f2fs_fs.h: NAT, SIT and summary entry formats.",
      "url": "https://github.com/torvalds/linux/blob/v6.12/include/linux/f2fs_fs.h",
      "accessed": "2026-10-21"
    },
    {
      "id": "manual",
      "title": "Linux 6.12 F2FS documentation: wandering tree, on-disk layout and metadata structure.",
      "url": "https://docs.kernel.org/6.12/filesystems/f2fs.html",
      "accessed": "2026-10-21"
    },
    {
      "id": "hesela-f2fs",
      "title": "F2FS: when a successful fsync is not a recovery promise",
      "url": "https://hesela.com/analyses/f2fs-checkpoint-fsync-recovery/#metadata-indirection",
      "accessed": "2026-10-21"
    }
  ]
}