# OpenZFS zfs-2.4.2

- Product: OpenZFS (https://whatsnew.fyi/product/openzfs)
- Vendor: OpenZFS
- Date: 2026-05-12
- Version: zfs-2.4.2
- Original notes: https://github.com/openzfs/zfs/releases/tag/zfs-2.4.2
- Permalink: https://whatsnew.fyi/product/openzfs/releases/zfs-2.4.2
- Labels: Platforms: Linux

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **fixed** — Fix incorrect variable rename in initramfs
- **fixed** — Fix long POSIX_FADV_DONTNEED for single block files
- **added** — Add support for POSIX_FADV_DONTNEED
- **changed** — Cleanup allocation class selection
- **fixed** — Fix uu_ident.c strchr() for GCC
- **changed** — libspl/mnttab: follow symlinks when resolving path via statx
- **fixed** — Fix vdev_rebuild_range() tx commit
- **fixed** — Fix redundant declaration of dsl_pool_t
- **changed** — Linux 7.1: access dentry d_alias directly
- **fixed** — Initialize vr_last_txg for rebuild
- **fixed** — Fix rare cksum errors after rebuild
- **changed** — build: use pax tar format for make dist
- **fixed** — Fix kernel BUG at mm/usercopy.c
- **fixed** — dmu_direct: avoid UAF in dmu_write_direct_done()
- **fixed** — Prevent range tree corruption race by updating dnode_sync()
- **fixed** — range_tree: use zfs_panic_recover() for partial-overlap remove
- **fixed** — Fix read corruption after block clone after truncate
- **fixed** — Fix snapshot automount deadlock during concurrent zfs recv
- **fixed** — Fix options memory leak in zfsctl_snapshot_mount
- **fixed** — Fix s_active leak in zfsvfs_hold() when z_unmounted is true

###### Supported Platforms
- **Linux**: compatible with 4.18 - 7.0 kernels
- **FreeBSD**: compatible with releases starting from 13.3+, 14.0+

###### Changes
- initramfs: fix incorrect variable rename #18442
- Fix long POSIX_FADV_DONTNEED for single block files #18399 #18489
- Add support for POSIX_FADV_DONTNEED #18399
- Cleanup allocation class selection #18208
- [2.4.2-only] GCC: Fix uu_ident.c strchr()
- libspl/mnttab: follow symlinks when resolving path via statx (#18469)
- Fix vdev_rebuild_range() tx commit #18276
- Fix redundant declaration of dsl_pool_t #18263
- CI: FreeBSD 15.1 PRERELEASE (#18490)
- CI/GCC: Add Fedora 44, fix build errors and threadsappend #18478
- Linux 7.1: access dentry d_alias directly #18471
- Initialize vr_last_txg for rebuild #18482
- Fix rare cksum errors after rebuild #18307 #18319 #18473
- ZTS: add targeted redundancy_draid_spare exception #18436
- build: use pax tar format for make dist
- CI: curl fallback, print killed tests, FreeBSD URL #18460
- Fix 'kernel BUG at mm/usercopy.c' #15918 #18408
- dmu_direct: avoid UAF in dmu_write_direct_done() #18440
- Prevent range tree corruption race by updating dnode_sync() #18235
- range_tree: use zfs_panic_recover() for partial-overlap remove #18255
- [zfs-2.4.2] Whitelist some Makefile.am files from SPDX
- Fix read corruption after block clone after truncate #18412 #18421
- Fix snapshot automount deadlock during concurrent zfs recv #18415
- Fix options memory leak in zfsctl_snapshot_mount #18415
- Fix s_active leak in zfsvfs_hold() when z_unmounted is true #18309 #18310
- fix memleak in spa_errlog.c #18403
- CI: Add more debugging to qemu-1-setup.sh #18441
- CI: tolerate missing artifacts #18438
- CI: Do not set scheduler in qemu-1-setup.sh #18437
- Linux 7.0 compat: META #18435
- deb.am: propagate build errors in native-deb targets #18206 #18424
- draid: fix cksum errors after rebuild with degraded disks #18414
- CI: Disable ZIP file artifacts, update versions #18411
- CI: set /etc/hostid in zloop runner #18413
- draid: allow seq resilver reads from degraded vdevs #18405
- Linux: Refactor zpl_fadvise() #18395
- CI: Free 35GB of unused files on the runner #18400
- linux/vfsops: remove zfs_mnt_t, pass directly #18377
- linux/super: work around kernels that enforce "forbidden" mount options #18377
- linux/super: implement new mount params parser #18377
- linux/super: match vfs_t lifetime to fs_context #18377
- linux/super: remove zpl_parse_monolithic #18377
- linux/vfsops: remove old options parser #18377
- linux/vfsops: add vfs_t allocator, make public #18377
- draid: fix import failure after disks replacements #18380
- Linux 7.0: ensure LSMs get to process mount options #18376
- ci: update FreeBSD CI images from 14.3 to 14.4 #18362
- Linux 7.0: autoconf: Remove copy-from-user-inatomic API checks (#18348) (#18354)
- CI: Add ARM builder #18343
- CI: Support repository variable override for ZTS OS selection #18342
- linux/super: flatten zpl_fill_super into zpl_get_tree #18339
- linux/super: flatten zpl_mount_impl into zpl_get_tree #18339
- linux/super: flatten mount/remount into get_tree/reconfigure #18339
- linux/super: remove support for old mount API #18339
- config: refuse to build without fs_context #18339
- Linux 7.0: also set setlease handler on directories (#18331)
- ZTS: Add back redundancy_draid_spare3 exception #18320
- ZTS: redundancy_draid_spare{1,3} exceptions #18308
- config: fix STATX_MNT_ID detection #18312
- draid: fix data corruption after disk clear #18286 #18294
- Fix deadlock on dmu_tx_assign() from vdev_rebuild() #18210 #18258
- README: describe specific kernels/distros we target #18295
- config: remove minimum kernel version check #18295
- libzfs: use mount_setattr for selective remount including legacy mounts #18257
- FreeBSD: Improve dmesg kernel message prefix #18290
- Fix check for .cfi_negate_ra_state on aarch64 #18262
- zpl_super: prefer "new" mount API

_[Truncated at 4000 characters — full notes: https://github.com/openzfs/zfs/releases/tag/zfs-2.4.2]_