On Wed, Sep 01, 2021 at 01:33:34AM +0200, Alexander Hall wrote:
> If two files to be compared share the same inode, it should
> be reasonable to consider them identical.
>
> This gives a substantial speedup when comparing directory
> structures with many hardlinked files, e.g. when using
> rsnapshot for incremental backup.
>
> Comments? OK?
ok stsp@
I have a side-project where I'll consider adding this, too.
> /Alexander
>
> Index: diffreg.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/diff/diffreg.c,v
> retrieving revision 1.93
> diff -u -p -r1.93 diffreg.c
> --- diffreg.c 28 Jun 2019 13:35:00 -0000 1.93
> +++ diffreg.c 31 Aug 2021 23:07:51 -0000
> @@ -429,6 +429,10 @@ files_differ(FILE *f1, FILE *f2, int fla
> 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);
> +
> for (;;) {
> i = fread(buf1, 1, sizeof(buf1), f1);
> j = fread(buf2, 1, sizeof(buf2), f2);
>
>
