Re: [PATCH 00/61] vfs: change inode->i_ino from unsigned long to u64

Christian König
2026-02-27T09:32:02Z

On 2/26/26 16:55, Jeff Layton wrote:
> Christian said [1] to "just do it" when I proposed this, so here we are!
>
> For historical reasons, the inode->i_ino field is an unsigned long,
> which means that it's 32 bits on 32 bit architectures. This has caused a
> number of filesystems to implement hacks to hash a 64-bit identifier
> into a 32-bit field, and deprives us of a universal identifier field for
> an inode.
>
> This patchset changes the inode->i_ino field from an unsigned long to a
> u64. This shouldn't make any material difference on 64-bit hosts, but
> 32-bit hosts will see struct inode grow by at least 4 bytes. This could
> have effects on slabcache sizes and field alignment.
>
> The bulk of the changes are to format strings and tracepoints, since the
> kernel itself doesn't care that much about the i_ino field. The first
> patch changes some vfs function arguments, so check that one out
> carefully.
>
> With this change, we may be able to shrink some inode structures. For
> instance, struct nfs_inode has a fileid field that holds the 64-bit
> inode number. With this set of changes, that field could be eliminated.
> I'd rather leave that sort of cleanups for later just to keep this
> simple.
>
> Much of this set was generated by LLM, but I attributed it to myself
> since I consider this to be in the "menial tasks" category of LLM usage.

Sounds reasonable to me, should get_next_ino() also be changed to return an 64bit ino?

Currently it is always only 32bit and we have workarounds for that in DMA-buf for example.

Thanks,
Christian.

>
> [1]: https://lore.kernel.org/linux-fsdevel/20260219-portrait-winkt-959070cee42f@brauner/
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> Jeff Layton (61):
> vfs: widen inode hash/lookup functions to u64
> vfs: change i_ino from unsigned long to u64
> trace: update VFS-layer trace events for u64 i_ino
> ext4: update for u64 i_ino
> jbd2: update format strings for u64 i_ino
> f2fs: update for u64 i_ino
> lockd: update format strings for u64 i_ino
> nfs: update for u64 i_ino
> nfs: remove nfs_fattr_to_ino_t() and nfs_fileid_to_ino_t()
> nfs: remove nfs_compat_user_ino64()
> nfs: remove enable_ino64 module parameter
> nfsd: update format strings for u64 i_ino
> smb: store full 64-bit uniqueid in i_ino
> smb: remove cifs_uniqueid_to_ino_t()
> locks: update /proc/locks format for u64 i_ino
> proc: update /proc/PID/maps for u64 i_ino
> nilfs2: update for u64 i_ino
> 9p: update format strings for u64 i_ino
> affs: update format strings for u64 i_ino
> afs: update format strings for u64 i_ino
> autofs: update format strings for u64 i_ino
> befs: update format strings for u64 i_ino
> bfs: update format strings for u64 i_ino
> cachefiles: update format strings for u64 i_ino
> ceph: update format strings for u64 i_ino
> coda: update format strings for u64 i_ino
> cramfs: update format strings for u64 i_ino
> ecryptfs: update format strings for u64 i_ino
> efs: update format strings for u64 i_ino
> exportfs: update format strings for u64 i_ino
> ext2: update format strings for u64 i_ino
> freevxfs: update format strings for u64 i_ino
> hfs: update format strings for u64 i_ino
> hfsplus: update format strings for u64 i_ino
> hpfs: update format strings for u64 i_ino
> isofs: update format strings for u64 i_ino
> jffs2: update format strings for u64 i_ino
> jfs: update format strings for u64 i_ino
> minix: update format strings for u64 i_ino
> nsfs: update format strings for u64 i_ino
> ntfs3: update format strings for u64 i_ino
> ocfs2: update format strings for u64 i_ino
> orangefs: update format strings for u64 i_ino
> overlayfs: update format strings for u64 i_ino
> qnx4: update format strings for u64 i_ino
> qnx6: update format strings for u64 i_ino
> ubifs: update format strings for u64 i_ino
> udf: update format strings for u64 i_ino
> ufs: update format strings for u64 i_ino
> zonefs: update format strings for u64 i_ino
> security: update audit format strings for u64 i_ino
> drm/amdgpu: update for u64 i_ino
> fsnotify: update fdinfo format strings for u64 i_ino
> net: update socket dname format for u64 i_ino
> uprobes: update format strings for u64 i_ino
> dma-buf: update format string for u64 i_ino
> fscrypt: update format strings for u64 i_ino
> fsverity: update format string for u64 i_ino
> iomap: update format string for u64 i_ino
> net: update legacy protocol format strings for u64 i_ino
> vfs: update core format strings for u64 i_ino
>
> drivers/dma-buf/dma-buf.c | 2 +-
> drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 4 +-
> fs/9p/vfs_addr.c | 4 +-
> fs/9p/vfs_inode.c | 6 +-
> fs/9p/vfs_inode_dotl.c | 6 +-
> fs/affs/amigaffs.c | 8 +-
> fs/affs/bitmap.c | 2 +-
> fs/affs/dir.c | 2 +-
> fs/affs/file.c | 20 +-
> fs/affs/inode.c | 12 +-
> fs/affs/namei.c | 14 +-
> fs/affs/symlink.c | 2 +-
> fs/afs/dir.c | 10 +-
> fs/afs/dir_search.c | 2 +-
> fs/afs/dynroot.c | 2 +-
> fs/afs/inode.c | 2 +-
> fs/autofs/inode.c | 2 +-
> fs/befs/linuxvfs.c | 28 +-
> fs/bfs/dir.c | 4 +-
> fs/cachefiles/io.c | 6 +-
> fs/cachefiles/namei.c | 12 +-
> fs/cachefiles/xattr.c | 2 +-
> fs/ceph/crypto.c | 4 +-
> fs/coda/dir.c | 2 +-
> fs/coda/inode.c | 2 +-
> fs/cramfs/inode.c | 2 +-
> fs/crypto/crypto.c | 2 +-
> fs/crypto/hooks.c | 2 +-
> fs/crypto/keysetup.c | 2 +-
> fs/dcache.c | 4 +-
> fs/ecryptfs/crypto.c | 6 +-
> fs/ecryptfs/file.c | 2 +-
> fs/efs/inode.c | 6 +-
> fs/eventpoll.c | 2 +-
> fs/exportfs/expfs.c | 4 +-
> fs/ext2/dir.c | 10 +-
> fs/ext2/ialloc.c | 9 +-
> fs/ext2/inode.c | 2 +-
> fs/ext2/xattr.c | 14 +-
> fs/ext4/dir.c | 2 +-
> fs/ext4/ext4.h | 4 +-
> fs/ext4/extents.c | 8 +-
> fs/ext4/extents_status.c | 28 +-
> fs/ext4/fast_commit.c | 8 +-
> fs/ext4/ialloc.c | 10 +-
> fs/ext4/indirect.c | 2 +-
> fs/ext4/inline.c | 14 +-
> fs/ext4/inode.c | 22 +-
> fs/ext4/ioctl.c | 4 +-
> fs/ext4/mballoc.c | 6 +-
> fs/ext4/migrate.c | 2 +-
> fs/ext4/move_extent.c | 20 +-
> fs/ext4/namei.c | 10 +-
> fs/ext4/orphan.c | 16 +-
> fs/ext4/page-io.c | 10 +-
> fs/ext4/super.c | 22 +-
> fs/ext4/xattr.c | 10 +-
> fs/f2fs/compress.c | 4 +-
> fs/f2fs/dir.c | 2 +-
> fs/f2fs/extent_cache.c | 8 +-
> fs/f2fs/f2fs.h | 6 +-
> fs/f2fs/file.c | 12 +-
> fs/f2fs/gc.c | 2 +-
> fs/f2fs/inline.c | 4 +-
> fs/f2fs/inode.c | 48 ++--
> fs/f2fs/namei.c | 8 +-
> fs/f2fs/node.c | 12 +-
> fs/f2fs/recovery.c | 10 +-
> fs/f2fs/xattr.c | 10 +-
> fs/freevxfs/vxfs_bmap.c | 4 +-
> fs/fserror.c | 2 +-
> fs/hfs/catalog.c | 2 +-
> fs/hfs/extent.c | 4 +-
> fs/hfs/inode.c | 4 +-
> fs/hfsplus/attributes.c | 10 +-
> fs/hfsplus/catalog.c | 2 +-
> fs/hfsplus/dir.c | 6 +-
> fs/hfsplus/extents.c | 6 +-
> fs/hfsplus/inode.c | 8 +-
> fs/hfsplus/super.c | 6 +-
> fs/hfsplus/xattr.c | 10 +-
> fs/hpfs/dir.c | 4 +-
> fs/hpfs/dnode.c | 4 +-
> fs/hpfs/ea.c | 4 +-
> fs/hpfs/inode.c | 4 +-
> fs/inode.c | 46 ++--
> fs/iomap/ioend.c | 2 +-
> fs/isofs/compress.c | 2 +-
> fs/isofs/dir.c | 2 +-
> fs/isofs/inode.c | 6 +-
> fs/isofs/namei.c | 2 +-
> fs/jbd2/journal.c | 4 +-
> fs/jbd2/transaction.c | 2 +-
> fs/jffs2/dir.c | 4 +-
> fs/jffs2/file.c | 4 +-
> fs/jffs2/fs.c | 18 +-
> fs/jfs/inode.c | 2 +-
> fs/jfs/jfs_imap.c | 2 +-
> fs/jfs/jfs_metapage.c | 2 +-
> fs/lockd/svclock.c | 8 +-
> fs/lockd/svcsubs.c | 2 +-
> fs/locks.c | 6 +-
> fs/minix/inode.c | 10 +-
> fs/nfs/dir.c | 22 +-
> fs/nfs/file.c | 8 +-
> fs/nfs/filelayout/filelayout.c | 8 +-
> fs/nfs/flexfilelayout/flexfilelayout.c | 8 +-
> fs/nfs/inode.c | 54 +---
> fs/nfs/nfs4proc.c | 4 +-
> fs/nfs/pnfs.c | 12 +-
> fs/nfsd/export.c | 2 +-
> fs/nfsd/nfs4state.c | 4 +-
> fs/nfsd/nfsfh.c | 4 +-
> fs/nfsd/vfs.c | 2 +-
> fs/nilfs2/alloc.c | 10 +-
> fs/nilfs2/bmap.c | 2 +-
> fs/nilfs2/btnode.c | 2 +-
> fs/nilfs2/btree.c | 12 +-
> fs/nilfs2/dir.c | 12 +-
> fs/nilfs2/direct.c | 4 +-
> fs/nilfs2/gcinode.c | 2 +-
> fs/nilfs2/inode.c | 8 +-
> fs/nilfs2/mdt.c | 2 +-
> fs/nilfs2/namei.c | 2 +-
> fs/nilfs2/segment.c | 2 +-
> fs/notify/fdinfo.c | 4 +-
> fs/nsfs.c | 4 +-
> fs/ntfs3/super.c | 2 +-
> fs/ocfs2/alloc.c | 2 +-
> fs/ocfs2/aops.c | 4 +-
> fs/ocfs2/dir.c | 8 +-
> fs/ocfs2/dlmfs/dlmfs.c | 10 +-
> fs/ocfs2/extent_map.c | 12 +-
> fs/ocfs2/inode.c | 2 +-
> fs/ocfs2/quota_local.c | 2 +-
> fs/ocfs2/refcounttree.c | 10 +-
> fs/ocfs2/xattr.c | 4 +-
> fs/orangefs/inode.c | 2 +-
> fs/overlayfs/export.c | 2 +-
> fs/overlayfs/namei.c | 4 +-
> fs/overlayfs/util.c | 2 +-
> fs/pipe.c | 2 +-
> fs/proc/fd.c | 2 +-
> fs/proc/task_mmu.c | 4 +-
> fs/qnx4/inode.c | 4 +-
> fs/qnx6/inode.c | 2 +-
> fs/smb/client/cifsfs.h | 17 --
> fs/smb/client/inode.c | 6 +-
> fs/smb/client/readdir.c | 2 +-
> fs/ubifs/debug.c | 8 +-
> fs/ubifs/dir.c | 28 +-
> fs/ubifs/file.c | 28 +-
> fs/ubifs/journal.c | 6 +-
> fs/ubifs/super.c | 16 +-
> fs/ubifs/tnc.c | 4 +-
> fs/ubifs/xattr.c | 14 +-
> fs/udf/directory.c | 18 +-
> fs/udf/file.c | 2 +-
> fs/udf/inode.c | 12 +-
> fs/udf/namei.c | 8 +-
> fs/udf/super.c | 2 +-
> fs/ufs/balloc.c | 6 +-
> fs/ufs/dir.c | 10 +-
> fs/ufs/ialloc.c | 6 +-
> fs/ufs/inode.c | 18 +-
> fs/ufs/ufs_fs.h | 6 +-
> fs/ufs/util.c | 2 +-
> fs/verity/init.c | 2 +-
> fs/zonefs/super.c | 8 +-
> include/linux/fs.h | 28 +-
> include/linux/nfs_fs.h | 10 -
> include/trace/events/cachefiles.h | 18 +-
> include/trace/events/ext4.h | 427 +++++++++++++++--------------
> include/trace/events/f2fs.h | 172 ++++++------
> include/trace/events/filelock.h | 16 +-
> include/trace/events/filemap.h | 20 +-
> include/trace/events/fs_dax.h | 20 +-
> include/trace/events/fsverity.h | 30 +-
> include/trace/events/hugetlbfs.h | 28 +-
> include/trace/events/netfs.h | 4 +-
> include/trace/events/nilfs2.h | 12 +-
> include/trace/events/readahead.h | 12 +-
> include/trace/events/timestamp.h | 12 +-
> include/trace/events/writeback.h | 148 +++++-----
> kernel/events/uprobes.c | 4 +-
> net/netrom/af_netrom.c | 4 +-
> net/rose/af_rose.c | 4 +-
> net/socket.c | 2 +-
> net/x25/x25_proc.c | 4 +-
> security/apparmor/apparmorfs.c | 4 +-
> security/integrity/integrity_audit.c | 2 +-
> security/ipe/audit.c | 2 +-
> security/lsm_audit.c | 10 +-
> security/selinux/hooks.c | 4 +-
> security/smack/smack_lsm.c | 12 +-
> 195 files changed, 1101 insertions(+), 1166 deletions(-)
> ---
> base-commit: 2bf35e96cf6c6c3a290b69b777d34be15888e364
> change-id: 20260224-iino-u64-b44a3a72543c
>
> Best regards,