{
  "id": 18528756,
  "title": "Linux 7.4-rc2 Change Yields As Much As 162x Improvement For FAT32",
  "url": "https://urgent.news/2026/11/06/linux-7-4-rc2-change-yields-as-much-as-162x-improvement-for-fat32",
  "topic": "finance",
  "section": "Finance & Markets",
  "published": "2026-11-06T16:21:38.000Z",
  "source": {
    "name": "Phoronix",
    "slug": "phoronix",
    "url": "https://www.phoronix.com/news/Linux-7.4-rc2-FAT32"
  },
  "original_language": "en",
  "account": "The latest Linux 7.4-rc2 change brings a remarkable performance boost of up to 162 times faster for FAT32 file systems. This significant improvement is achieved by streamlining the allocation of new clusters within the file system. Previously, the fat_cont_expand() implementation relied on generic_cont_expand_simple() for allocation, which resulted in numerous small cluster allocations, ultimately hampering overall performance.\n\nTo address this issue, the developers introduced a new helper function called fat_preallocate(), which is utilized by both fat_cont_expand() and fat_fallocate(FALLOC_FL_KEEP_SIZE). This new approach preallocates cluster space in advance, eliminating the need for multiple small allocations during the expansion process. Additionally, a specialized FAT-specific fat_cont_expand_simple() function replaces the generic_cont_expand_simple() function, thereby avoiding the redundant check of the new size after cluster allocation.\n\nThe main beneficiaries of this change are systems using OCFS2 file systems, which have long been plagued by issues such as extended-attribute corruption, missing attributes, kernel BUGs, and crashes during various file system operations. The FAT-specific modifications also tackle three critical problems that could otherwise lead to a failed-write/FIBMAP race, causing the filesystem to become read-only spuriously, incorrect directory link counts after renaming, and slower file expansion times.\n\nNotably, the reported QEMU benchmarks demonstrate the most significant impact of this modification, with particularly large performance improvements observed on synchronous mounts. Furthermore, the change includes essential fixes for OpenRISC modules on CPUs lacking hardware multiplication support, as well as compatibility with Clang 24.\n\nFrom a security standpoint, this update addresses a potential taint-string vulnerability, which could have exposed sensitive slab contents in the kernel log through an out-of-bounds read. Lastly, the change encompasses various build fixes for improved compatibility across different systems.",
  "summary": "In addition to a FAT32 optimization yielding as much as a 265x improvement that was merged for the Linux 7.4 cycle and separately another big FAT32 improvement expected for Linux 7.5, merged this week as part of the non-MM fixes for Linux 7.4-rc2 was another big FAT32 performance optimization...",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}