On Fri, Jul 15, 2011 at 08:48:18PM -0600, Eric Blake wrote:
Constraining the problem makes the solution easier to think about.
* src/util/iohelper.c (runIO): Make read support easy. ---
Could be squashed into 6/8.
src/util/iohelper.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/src/util/iohelper.c b/src/util/iohelper.c index 82f62e1..f091d13 100644 --- a/src/util/iohelper.c +++ b/src/util/iohelper.c @@ -107,6 +107,13 @@ runIO(const char *path, int fd, int oflags, unsigned long long length) fdinname = path; fdout = STDOUT_FILENO; fdoutname = "stdout"; + /* To make the implementation simpler, we give up on any + * attempt to use O_DIRECT in a non-trivial manner. */ + if (direct && ((end = lseek(fd, 0, SEEK_CUR)) != 0 || length)) { + virReportSystemError(end < 0 ? errno : EINVAL, "%s", + _("O_DIRECT read needs entire seekable file")); + goto cleanup; + } break; case O_WRONLY: fdin = STDIN_FILENO; @@ -117,7 +124,7 @@ runIO(const char *path, int fd, int oflags, unsigned long long length) * attempt to use O_DIRECT in a non-trivial manner. */ if (direct && (end = lseek(fd, 0, SEEK_END)) != 0) { virReportSystemError(end < 0 ? errno : EINVAL, "%s", - _("O_DIRECT needs empty seekable file")); + _("O_DIRECT write needs empty seekable file")); goto cleanup; } break;
ACK, if this really works for saving guests. We need to skip over the initial header + XML in save files, so I would have thought we needed to support a non-empty seekable file. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|