Date: Thu, 07 Oct 2021 09:40:54 -0600 From: Ian Lepore <ian@freebsd.org> To: Alan Somers <asomers@freebsd.org>, Mariusz Zaborski <oshogbo@freebsd.org> Cc: src-committers <src-committers@freebsd.org>, "<dev-commits-src-all@freebsd.org>" <dev-commits-src-all@freebsd.org>, dev-commits-src-main@freebsd.org Subject: Re: git: 824bbb9a4082 - main - diff: consider two files with same inodes as identical Message-ID: <e479e95ebc85acf4eda0e729d3e6373de674fd13.camel@freebsd.org> In-Reply-To: <CAOtMX2gfBsuXSCCfN-8EQHR%2ByCVOu8qJ7_3BxLxe=dDqY_9uEw@mail.gmail.com> References: <202110071509.197F9kqv094488@gitrepo.freebsd.org> <CAOtMX2gfBsuXSCCfN-8EQHR%2ByCVOu8qJ7_3BxLxe=dDqY_9uEw@mail.gmail.com>
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On Thu, 2021-10-07 at 09:32 -0600, Alan Somers wrote: > On Thu, Oct 7, 2021 at 9:09 AM Mariusz Zaborski <oshogbo@freebsd.org> > wrote: > > > > The branch main has been updated by oshogbo: > > > > URL: > > https://cgit.FreeBSD.org/src/commit/?id=824bbb9a40820fb62bde0a91c0f13e0b894da149 > > > > commit 824bbb9a40820fb62bde0a91c0f13e0b894da149 > > Author: Mariusz Zaborski <oshogbo@FreeBSD.org> > > AuthorDate: 2021-10-07 15:07:00 +0000 > > Commit: Mariusz Zaborski <oshogbo@FreeBSD.org> > > CommitDate: 2021-10-07 15:07:00 +0000 > > > > diff: consider two files with same inodes as identical > > > > Obtained from: OpenBSD > > MFC after: 1 week > > --- > > usr.bin/diff/diffreg.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/usr.bin/diff/diffreg.c b/usr.bin/diff/diffreg.c > > index fc3c3406a073..995843f9e539 100644 > > --- a/usr.bin/diff/diffreg.c > > +++ b/usr.bin/diff/diffreg.c > > @@ -440,6 +440,10 @@ files_differ(FILE *f1, FILE *f2, int flags) > > if ((flags & (D_EMPTY1|D_EMPTY2)) || stb1.st_size != > > stb2.st_size || > > (stb1.st_mode & S_IFMT) != (stb2.st_mode & S_IFMT)) > > return (1); > > + > > + if (stb1.st_dev == stb2.st_dev && stb1.st_ino == > > stb2.st_ino) > > + return (0); > > + > > Checking st_dev is not correct. It does necessarily bear any > relation > to the specific mounted file system. It might, but that's up to the > file system driver. fusefs, for example, allows the server to > populate that field with whatever it damn well pleases. diff should > use statfs instead, and check the f_fsid field. That would probably > work. > -Alan That may be a fusefs bug, then. Posix states The st_ino and st_dev fields taken together uniquely identify the file within the system. And I've seen real-world code more than once that uses st_dev equality to decide whether to rename versus copy-and-delete a file. -- Ian
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