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"
/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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