"tar tfv /dev/cd0" speedup patch
Juergen Lock
nox at jelal.kn-bremen.de
Fri Feb 19 18:24:11 UTC 2010
On Thu, Feb 18, 2010 at 10:12:24PM -0800, Garrett Cooper wrote:
> On Thu, Feb 18, 2010 at 10:34 AM, Juergen Lock <nox at jelal.kn-bremen.de> wrote:
> > On Wed, Feb 17, 2010 at 10:38:30PM -0800, Tim Kientzle wrote:
> >> Juergen Lock wrote:
> >> >
> >> > ... since bsdtar/libarchive know iso9660 I just did the command in the
> >> > Subject. It worked, but it was sloow... :( Apparently it read all of
> >> > the disc without seeking. The following patch fixes this, is something
> >> > like this desired? If yes I could look how to do the same for Linux,
> >>
> >> Juergen,
> >>
> >> This is great! If you can figure out how to get this
> >> right, I would really appreciate it. If you have a
> >> tape drive handy, definitely test with that. My first
> >> attempts here actually broke reading from tape drives,
> >> which is why the current code is so conservative.
> >>
> > Hmm I can't test on a tape atm but if I look at the kernel,
> > http://fxr.watson.org/fxr/ident?i=DIOCGMEDIASIZE
> > DIOCGMEDIASIZE is only handled for geom, xen block devices, old CD drives
> > and pc98 floppies, and I'm pretty sure tapes don't use geom. :)
> >
> >> Minor style comments:
> >> > else if (S_ISCHR(st.st_mode) &&
> >> > !ioctl(fd, DIOCGMEDIASIZE, &mediasize) && mediasize) {
> >>
> >> Please be explicit: S_ISCHR() && ioctl() == 0 && mediasize > 0
> >>
> >> > archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino);
> >>
> >> extract_skip_file isn't needed here; we don't read the
> >> contents of device nodes.
> >>
> >> Let me know as soon as you have something you're confident of.
> >
> > Ok here is a new version of the patch with these things fixed and the
> > Linux case added: (Linux case not tested yet, and yes I did this on
> > stable/8.)
> >
> > Index: src/lib/libarchive/archive_read_open_filename.c
> > ===================================================================
> > RCS file: /home/scvs/src/lib/libarchive/archive_read_open_filename.c,v
> > retrieving revision 1.25.2.1
> > diff -u -p -r1.25.2.1 archive_read_open_filename.c
> > --- src/lib/libarchive/archive_read_open_filename.c 3 Aug 2009 08:13:06 -0000 1.25.2.1
> > +++ src/lib/libarchive/archive_read_open_filename.c 18 Feb 2010 18:14:16 -0000
> > @@ -44,6 +44,10 @@ __FBSDID("$FreeBSD: src/lib/libarchive/a
> > #ifdef HAVE_UNISTD_H
> > #include <unistd.h>
> > #endif
> > +#ifdef __FreeBSD__
> > +#include <sys/ioctl.h>
> > +#include <sys/disk.h>
> > +#endif
> >
> > #include "archive.h"
> >
> > @@ -83,6 +87,9 @@ archive_read_open_filename(struct archiv
> > struct read_file_data *mine;
> > void *b;
> > int fd;
> > +#ifdef __FreeBSD__
> > + off_t mediasize = 0;
> > +#endif
> >
> > archive_clear_error(a);
> > if (filename == NULL || filename[0] == '\0') {
> > @@ -143,6 +150,27 @@ archive_read_open_filename(struct archiv
> > */
> > mine->can_skip = 1;
> > }
> > +#ifdef __FreeBSD__
> > + /*
> > + * on FreeBSD if a device supports the DIOCGMEDIASIZE ioctl
> > + * it is a disk-like device and should be seekable.
> > + */
> > + else if (S_ISCHR(st.st_mode) &&
> > + ioctl(fd, DIOCGMEDIASIZE, &mediasize) == 0 && mediasize > 0) {
> > + mine->can_skip = 1;
> > + }
> > +#endif
> > +#ifdef __linux__
>
> Is there any reason why a) you wouldn't check for other BSDs? b) you
> aren't doing something of the flavor...
>
> #if defined(__FreeBSD__)
>
> #elif defined(__linux__)
>
> #endif
Okok, here's a new version of the patch that now also knows about
other BSDs and switched to #elif: (only NetBSD actually tested tho
since I had a VM lying around, more testing welcome!)
(Also if anyone wants to switch this to autoconf-style HAVE_FOO
handling they are welcome too... :)
Enjoy,
Juergen
Index: src/lib/libarchive/archive_read_open_filename.c
===================================================================
RCS file: /home/scvs/src/lib/libarchive/archive_read_open_filename.c,v
retrieving revision 1.25.2.1
diff -u -p -u -p -r1.25.2.1 archive_read_open_filename.c
--- src/lib/libarchive/archive_read_open_filename.c 3 Aug 2009 08:13:06 -0000 1.25.2.1
+++ src/lib/libarchive/archive_read_open_filename.c 19 Feb 2010 18:18:24 -0000
@@ -44,6 +44,17 @@ __FBSDID("$FreeBSD: src/lib/libarchive/a
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
+#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#include <sys/ioctl.h>
+#include <sys/disk.h>
+#elif defined(__NetBSD__) || defined(__OpenBSD__)
+#include <sys/ioctl.h>
+#include <sys/disklabel.h>
+#include <sys/dkio.h>
+#elif defined(__DragonFly__)
+#include <sys/ioctl.h>
+#include <sys/diskslice.h>
+#endif
#include "archive.h"
@@ -83,6 +94,13 @@ archive_read_open_filename(struct archiv
struct read_file_data *mine;
void *b;
int fd;
+#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+ off_t mediasize = 0;
+#elif defined(__NetBSD__) || defined(__OpenBSD__)
+ struct disklabel dl;
+#elif defined(__DragonFly__)
+ struct partinfo pi;
+#endif
archive_clear_error(a);
if (filename == NULL || filename[0] == '\0') {
@@ -143,6 +161,45 @@ archive_read_open_filename(struct archiv
*/
mine->can_skip = 1;
}
+#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+ /*
+ * on FreeBSD if a device supports the DIOCGMEDIASIZE ioctl
+ * it is a disk-like device and should be seekable.
+ */
+ else if (S_ISCHR(st.st_mode) &&
+ ioctl(fd, DIOCGMEDIASIZE, &mediasize) == 0 && mediasize > 0) {
+ mine->can_skip = 1;
+ }
+#elif defined(__NetBSD__) || defined(__OpenBSD__)
+ /*
+ * on Net/OpenBSD if a device supports the DIOCGDINFO ioctl
+ * it is a disk-like device and should be seekable.
+ */
+ else if ((S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) &&
+ ioctl(fd, DIOCGDINFO, &dl) == 0 &&
+ dl.d_partitions[DISKPART(st.st_rdev)].p_size > 0) {
+ mine->can_skip = 1;
+ }
+#elif defined(__DragonFly__)
+ /*
+ * on DragonFly BSD if a device supports the DIOCGPART ioctl
+ * it is a disk-like device and should be seekable.
+ */
+ else if (S_ISCHR(st.st_mode) &&
+ ioctl(fd, DIOCGPART, &pi) == 0 && pi.media_size > 0) {
+ mine->can_skip = 1;
+ }
+#elif defined(__linux__)
+ /*
+ * on Linux just check whether its a block device and that
+ * lseek works. (Tapes are character devices there.)
+ */
+ else if (S_ISBLK(st.st_mode) &&
+ lseek(fd, 0, SEEK_CUR) == 0 && lseek(fd, 0, SEEK_SET) == 0 &&
+ lseek(fd, 0, SEEK_END) > 0 && lseek(fd, 0, SEEK_SET) == 0) {
+ mine->can_skip = 1;
+ }
+#endif
return (archive_read_open2(a, mine,
NULL, file_read, file_skip, file_close));
}
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