> On Wed, Oct 23, 2019 at 04:07:52PM -0400, Vivek Goyal wrote:
> > On Wed, Oct 23, 2019 at 09:25:23PM +0900, Misono Tomohiro wrote:
> > > When writeback mode is enabled (-o writeback), O_APPEND handling is
> > > done in kernel. Therefore virtiofsd clears O_APPEND flag when open.
> > > Otherwise O_APPEND flag takes precedence over pwrite() and write
> > > data may corrupt.
> > >
> > > Currently clearing O_APPEND flag is done in lo_open(), but we also
> > > need the same operation in lo_create().
> >
> > > So, factor out the flag
> > > update operation in lo_open() to update_open_flags() and call it in
> > > both lo_open() and lo_create().
> > >
> > > This fixes the failure of xfstest generic/069 in writeback mode
> > > (which tests O_APPEND write data integrity).
> > >
>
> Hi Misono,
>
> Have you tried running pjdfstests. Looks like with the patch applied I see
> following tests failing which were passing without
> the patch. Can you please have a look. I ran daemon with options "-o
> cache=always -o writeback"
Sorry, I didn't run pjdfstests. I will run the test and check the results.
Thanks,
Misono
>
> /root/git/pjdfstest/tests/chmod/00.t (Wstat: 0 Tests: 119 Failed: 1)
> Failed test: 64
> /root/git/pjdfstest/tests/chown/00.t (Wstat: 0 Tests: 1323 Failed: 1)
> Failed test: 946
> TODO passed: 1107, 1112, 1116, 1122, 1127, 1131, 1137
> 1142, 1146, 1152, 1157, 1161, 1167, 1172
> 1176, 1182, 1187
> /root/git/pjdfstest/tests/link/00.t (Wstat: 0 Tests: 202 Failed: 1)
> Failed test: 134
> /root/git/pjdfstest/tests/utimensat/01.t (Wstat: 0 Tests: 7 Failed: 1)
> Failed test: 4
> Files=232, Tests=8789, 375 wallclock secs ( 4.00 usr 2.65 sys + 51.48 cusr
> 262.19 csys = 320.32 CPU) Thanks Vivek
>
> >
> > Hi,
> >
> > Consolidating updation of flags both for lo_create() and lo_open()
> > makes sense to me. I will test it tomorrow.
> >
> > Thanks
> > Vivek
> >
> > > Signed-off-by: Misono Tomohiro <misono.tomoh...@jp.fujitsu.com>
> > > ---
> > > contrib/virtiofsd/passthrough_ll.c | 56
> > > +++++++++++++++---------------
> > > 1 file changed, 28 insertions(+), 28 deletions(-)
> > >
> > > diff --git a/contrib/virtiofsd/passthrough_ll.c
> > > b/contrib/virtiofsd/passthrough_ll.c
> > > index e8892c3c32..79fb78ecce 100644
> > > --- a/contrib/virtiofsd/passthrough_ll.c
> > > +++ b/contrib/virtiofsd/passthrough_ll.c
> > > @@ -1733,6 +1733,32 @@ static void lo_releasedir(fuse_req_t req,
> > > fuse_ino_t ino, struct fuse_file_info
> > > fuse_reply_err(req, 0);
> > > }
> > >
> > > +static void update_open_flags(int writeback, struct fuse_file_info
> > > +*fi) {
> > > + /* With writeback cache, kernel may send read requests even
> > > + when userspace opened write-only */
> > > + if (writeback && (fi->flags & O_ACCMODE) == O_WRONLY) {
> > > + fi->flags &= ~O_ACCMODE;
> > > + fi->flags |= O_RDWR;
> > > + }
> > > +
> > > + /* With writeback cache, O_APPEND is handled by the kernel.
> > > + This breaks atomicity (since the file may change in the
> > > + underlying filesystem, so that the kernel's idea of the
> > > + end of the file isn't accurate anymore). In this example,
> > > + we just accept that. A more rigorous filesystem may want
> > > + to return an error here */
> > > + if (writeback && (fi->flags & O_APPEND))
> > > + fi->flags &= ~O_APPEND;
> > > +
> > > + /*
> > > + * O_DIRECT in guest should not necessarily mean bypassing page
> > > + * cache on host as well. If somebody needs that behavior, it
> > > + * probably should be a configuration knob in daemon.
> > > + */
> > > + fi->flags &= ~O_DIRECT;
> > > +}
> > > +
> > > static void lo_create(fuse_req_t req, fuse_ino_t parent, const char
> > > *name,
> > > mode_t mode, struct fuse_file_info *fi) { @@ -1760,12
> > > +1786,7 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const
> > > char *name,
> > > if (err)
> > > goto out;
> > >
> > > - /*
> > > - * O_DIRECT in guest should not necessarily mean bypassing page
> > > - * cache on host as well. If somebody needs that behavior, it
> > > - * probably should be a configuration knob in daemon.
> > > - */
> > > - fi->flags &= ~O_DIRECT;
> > > + update_open_flags(lo->writeback, fi);
> > >
> > > fd = openat(parent_inode->fd, name,
> > > (fi->flags | O_CREAT) & ~O_NOFOLLOW, mode); @@ -1966,28
> > > +1987,7 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino,
> > > struct fuse_file_info *fi)
> > >
> > > fuse_log(FUSE_LOG_DEBUG, "lo_open(ino=%" PRIu64 ", flags=%d)\n",
> > > ino, fi->flags);
> > >
> > > - /* With writeback cache, kernel may send read requests even
> > > - when userspace opened write-only */
> > > - if (lo->writeback && (fi->flags & O_ACCMODE) == O_WRONLY) {
> > > - fi->flags &= ~O_ACCMODE;
> > > - fi->flags |= O_RDWR;
> > > - }
> > > -
> > > - /* With writeback cache, O_APPEND is handled by the kernel.
> > > - This breaks atomicity (since the file may change in the
> > > - underlying filesystem, so that the kernel's idea of the
> > > - end of the file isn't accurate anymore). In this example,
> > > - we just accept that. A more rigorous filesystem may want
> > > - to return an error here */
> > > - if (lo->writeback && (fi->flags & O_APPEND))
> > > - fi->flags &= ~O_APPEND;
> > > -
> > > - /*
> > > - * O_DIRECT in guest should not necessarily mean bypassing page
> > > - * cache on host as well. If somebody needs that behavior, it
> > > - * probably should be a configuration knob in daemon.
> > > - */
> > > - fi->flags &= ~O_DIRECT;
> > > + update_open_flags(lo->writeback, fi);
> > >
> > > sprintf(buf, "%i", lo_fd(req, ino));
> > > fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
> > > --
> > > 2.21.0
> > >
> > > _______________________________________________
> > > Virtio-fs mailing list
> > > virtio...@redhat.com
> > > https://www.redhat.com/mailman/listinfo/virtio-fs
> >
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> > virtio...@redhat.com
> > https://www.redhat.com/mailman/listinfo/virtio-fs
