Date: Thu, 5 Dec 2024 19:15:33 -0800 From: Rick Macklem <rick.macklem@gmail.com> To: Jessica Clarke <jrtc27@freebsd.org> Cc: Rick Macklem <rmacklem@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@freebsd.org>, "dev-commits-src-main@freebsd.org" <dev-commits-src-main@freebsd.org> Subject: Re: git: bfc8e3308bee - main - ext2fs: Fix the size of struct ufid and add a static assert Message-ID: <CAM5tNy5Wz-_JyRftJJe5MkzykvtGvg=4c5akfAjWc=_rTiqNaA@mail.gmail.com> In-Reply-To: <C69375D0-E5C4-4571-BDE2-5CC796C9E597@freebsd.org> References: <202412060206.4B6266Ja096452@gitrepo.freebsd.org> <C69375D0-E5C4-4571-BDE2-5CC796C9E597@freebsd.org>
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On Thu, Dec 5, 2024 at 6:40=E2=80=AFPM Jessica Clarke <jrtc27@freebsd.org> = wrote: > > CAUTION: This email originated from outside of the University of Guelph. = Do not click links or open attachments unless you recognize the sender and = know the content is safe. If in doubt, forward suspicious emails to IThelp@= uoguelph.ca. > > > On 6 Dec 2024, at 02:06, Rick Macklem <rmacklem@FreeBSD.org> wrote: > > > > The branch main has been updated by rmacklem: > > > > URL: https://cgit.FreeBSD.org/src/commit/?id=3Dbfc8e3308bee23d0f7836d57= f32ed8d47da02627 > > > > commit bfc8e3308bee23d0f7836d57f32ed8d47da02627 > > Author: Rick Macklem <rmacklem@FreeBSD.org> > > AuthorDate: 2024-12-06 02:05:06 +0000 > > Commit: Rick Macklem <rmacklem@FreeBSD.org> > > CommitDate: 2024-12-06 02:05:06 +0000 > > > > ext2fs: Fix the size of struct ufid and add a static assert > > > > File system specific *fid structures are copied into the generic > > struct fid defined in sys/mount.h. > > As such, they cannot be larger than struct fid. > > > > This patch packed the structure and checks via a __Static_assert(). > > > > Reviewed by: markj > > MFC after: 2 weeks > > --- > > sys/fs/ext2fs/ext2_vnops.c | 2 ++ > > sys/fs/ext2fs/inode.h | 2 +- > > 2 files changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/sys/fs/ext2fs/ext2_vnops.c b/sys/fs/ext2fs/ext2_vnops.c > > index dfbb11f75421..064c10bd18b2 100644 > > --- a/sys/fs/ext2fs/ext2_vnops.c > > +++ b/sys/fs/ext2fs/ext2_vnops.c > > @@ -1889,6 +1889,8 @@ ext2_vptofh(struct vop_vptofh_args *ap) > > { > > struct inode *ip; > > struct ufid *ufhp; > > + _Static_assert(sizeof(struct ufid) <=3D sizeof(struct fid), > > + "struct ufid cannot be larger than struct fid"); > > > > ip =3D VTOI(ap->a_vp); > > ufhp =3D (struct ufid *)ap->a_fhp; > > diff --git a/sys/fs/ext2fs/inode.h b/sys/fs/ext2fs/inode.h > > index 9ee1b5672da6..63102deb10b0 100644 > > --- a/sys/fs/ext2fs/inode.h > > +++ b/sys/fs/ext2fs/inode.h > > @@ -191,7 +191,7 @@ struct ufid { > > uint16_t ufid_pad; /* Force 32-bit alignment. */ > > ino_t ufid_ino; /* File number (ino). */ > > uint32_t ufid_gen; /* Generation number. */ > > -}; > > +} __packed; > > Why not just swap ufid_ino and ufid_gen? This will give worse codegen > on architectures that don=E2=80=99t assume fast unaligned access. You can commit such a change if you'd like, as far as I am concerned. I suspect few (if any) export ext2fs file systems anyhow, so this structure is unlikely to ever be used. There was a discussion on phabricator in D47879 about reordering entries and the consensus there seemed to be avoid doing that, although admittedly I think they were referring to the first two fields, which match the ones in the generic "struct fid". rick > > Jess >
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