On Friday 26 February 2010 4:09:52 pm Juergen Lock wrote: > On Fri, Feb 26, 2010 at 11:21:05AM -0500, John Baldwin wrote: > > On Thursday 25 February 2010 3:28:50 pm Juergen Lock wrote: > > > On Tue, Feb 23, 2010 at 10:50:10PM +0100, Juergen Lock wrote: > > > > Hi! > > > > > > > > Before this gets buried on -hackers in another thead... :) > > > > > > > > I now have disks appear as block devices for Linux processes (there > > > > already was commented out code for that in linux_stats.c, I hope my > > > > version is now `correct enough' to be usable [1]), and I made a simple > > > > patch to make lseek SEEK_END (L_XTND in the source) dtrt on disk > > > > devices too by simply invoking the DIOCGMEDIASIZE ioctl there; [2] > > > > both of these things are what (some) Linux processes expect. > > > > > > > > Patches are here: (made on stable/8, if they don't apply on head > > > > I'll have to make extra versions for that...) > > > > http://people.freebsd.org/~nox/linuxdisk-blk.patch [1] > > > > http://people.freebsd.org/~nox/lseek-seek_end.patch [2] > > > > > > > > And yes, with these patches the Linux bsdtar mentioned on -hackers > > > > in the `"tar tfv /dev/cd0" speedup patch' thread now also runs fast > > > > on FreeBSD. :) > > > > > > I now added an vn_isdisk() check to the second patch after comments from > > > julian, and I made a new patch that adds an overflow check to the 32 bit > > > linux lseek: (also at > > > http://people.freebsd.org/~nox/linux-lseek-overflow.patch > > > ) > > > > Hmm, when I asked Bruce, he actually said it was a feature that you didn't use > > vn_isdisk(). He also suggested that the proper way to fix lseek on devices is > > to fix stat in devfs to return a non-zero size. I have a possible fix to do > > that but haven't tested it yet: > > > > Index: devfs_vnops.c > > =================================================================== > > --- devfs_vnops.c (revision 204207) > > +++ devfs_vnops.c (working copy) > > @@ -44,6 +44,7 @@ > > #include <sys/systm.h> > > #include <sys/conf.h> > > #include <sys/dirent.h> > > +#include <sys/disk.h> > > #include <sys/fcntl.h> > > #include <sys/file.h> > > #include <sys/filedesc.h> > > @@ -564,7 +565,11 @@ > > struct vattr *vap = ap->a_vap; > > int error = 0; > > struct devfs_dirent *de; > > + struct cdevsw *dsw; > > + struct thread *td; > > + struct file *fpop; > > struct cdev *dev; > > + off_t size; > > > > de = vp->v_data; > > KASSERT(de != NULL, ("Null dirent in devfs_getattr vp=%p", vp)); > > @@ -612,6 +617,18 @@ > > vap->va_ctime = dev->si_ctime; > > > > vap->va_rdev = cdev2priv(dev)->cdp_inode; > > + > > + dsw = dev_refthread(dev); > > + if (dsw != NULL) { > > + td = curthread; > > + fpop = td->td_fpop; > > + td->td_fpop = NULL; > > + if (dsw->d_ioctl(dev, DIOCGMEDIASIZE, (caddr_t)&size, > > + FREAD, td) == 0) > > + vap->va_size = size; > > + td->td_fpop = fpop; > > + dev_relthread(dev); > > + } > > } > > vap->va_gen = 0; > > vap->va_flags = 0; > > > > I had to add an D_DISK check, else it would panic at boot in a revoke > syscall in ttydev_ioctl in ttydev_enter, apparently in the tty_lock call: > (I didn't get a dump as it panic'd way too early in boot) > http://fxr.watson.org/fxr/source/kern/tty.c#L159 > > Maybe dev->si_drv1 is null here? > http://fxr.watson.org/fxr/source/kern/tty.c#L486 > > Anyway, with the D_DISK check added the patch seems to work:
Unfortunately it panics in g_dev_ioctl() with INVARIANTS enabled. I will bug phk about that. -- John Baldwin _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
