On Tue, 1 Jun 2010 19:47:14 +0530 "M. Mohan Kumar" <mo...@in.ibm.com> wrote:
> Compute iounit based on the host filesystem block size and pass it to > client with open/create response. Also return iounit as statfs's f_bsize > for optimal block size transfers. > > Signed-off-by: M. Mohan Kumar <mo...@in.ibm.com> > --- > hw/virtio-9p.c | 56 > ++++++++++++++++++++++++++++++++++++++++++-------------- > hw/virtio-9p.h | 3 +++ > 2 files changed, 45 insertions(+), 14 deletions(-) > > diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c > index f087122..4357f1f 100644 > --- a/hw/virtio-9p.c > +++ b/hw/virtio-9p.c > @@ -1,4 +1,4 @@ > -/* > + /* > * Virtio 9p backend > * > * Copyright IBM, Corp. 2010 > @@ -269,6 +269,11 @@ static int v9fs_do_fsync(V9fsState *s, int fd) > return s->ops->fsync(&s->ctx, fd); > } > > +static int v9fs_do_statfs(V9fsState *s, V9fsString *path, struct statfs > *stbuf) > +{ > + return s->ops->statfs(&s->ctx, path->data, stbuf); > +} > + > static void v9fs_string_init(V9fsString *str) > { > str->data = NULL; > @@ -1035,11 +1040,10 @@ static void v9fs_fix_path(V9fsString *dst, V9fsString > *src, int len) > > static void v9fs_version(V9fsState *s, V9fsPDU *pdu) > { > - int32_t msize; > V9fsString version; > size_t offset = 7; > > - pdu_unmarshal(pdu, offset, "ds", &msize, &version); > + pdu_unmarshal(pdu, offset, "ds", &s->msize, &version); > > if (!strcmp(version.data, "9P2000.u")) { > s->proto_version = V9FS_PROTO_2000U; > @@ -1049,7 +1053,7 @@ static void v9fs_version(V9fsState *s, V9fsPDU *pdu) > v9fs_string_sprintf(&version, "unknown"); > } > > - offset += pdu_marshal(pdu, offset, "ds", msize, &version); > + offset += pdu_marshal(pdu, offset, "ds", s->msize, &version); > complete_pdu(s, pdu, offset); > > v9fs_string_free(&version); > @@ -1304,6 +1308,20 @@ out: > v9fs_walk_complete(s, vs, err); > } > > +static int32_t get_iounit(V9fsState *s, V9fsString *name) > +{ > + struct statfs stbuf; > + int32_t iounit = 0; > + > + > + if (!v9fs_do_statfs(s, name, &stbuf)) { > + iounit = stbuf.f_bsize; > + iounit *= (s->msize - P9_IOHDRSZ)/stbuf.f_bsize; If (s->msize - P9_IOHDRSZ) is less than stbuf.f_bsize iounit becomes zero. See below. > + } > + > + return iounit; > +} > + > static void v9fs_open_post_opendir(V9fsState *s, V9fsOpenState *vs, int err) > { > if (vs->fidp->dir == NULL) { > @@ -1321,12 +1339,15 @@ out: > > static void v9fs_open_post_open(V9fsState *s, V9fsOpenState *vs, int err) > { > + int32_t iounit; > + > if (vs->fidp->fd == -1) { > err = -errno; > goto out; > } > > - vs->offset += pdu_marshal(vs->pdu, vs->offset, "Qd", &vs->qid, 0); > + iounit = get_iounit(s, &vs->fidp->path); > + vs->offset += pdu_marshal(vs->pdu, vs->offset, "Qd", &vs->qid, iounit); > err = vs->offset; > out: > complete_pdu(s, vs->pdu, err); > @@ -1800,11 +1821,16 @@ out: > > static void v9fs_post_create(V9fsState *s, V9fsCreateState *vs, int err) > { > + int32_t iounit; > + > + iounit = get_iounit(s, &vs->fidp->path); > + > if (err == 0) { > v9fs_string_copy(&vs->fidp->path, &vs->fullname); > stat_to_qid(&vs->stbuf, &vs->qid); > > - vs->offset += pdu_marshal(vs->pdu, vs->offset, "Qd", &vs->qid, 0); > + vs->offset += pdu_marshal(vs->pdu, vs->offset, "Qd", &vs->qid, > + iounit); > > err = vs->offset; > } > @@ -2295,23 +2321,25 @@ out: > qemu_free(vs); > } > > -static int v9fs_do_statfs(V9fsState *s, V9fsString *path, struct statfs > *stbuf) > -{ > - return s->ops->statfs(&s->ctx, path->data, stbuf); > -} > - > static void v9fs_statfs_post_statfs(V9fsState *s, V9fsStatfsState *vs, int > err) > { > + int32_t bsize_factor; > + > if (err) { > err = -errno; > goto out; > } > > + bsize_factor = (s->msize - P9_IOHDRSZ)/vs->stbuf.f_bsize; > + if (!bsize_factor) { > + bsize_factor = 1; > + } Again, if (s->msize - P9_IOHDRSZ) is less than stbuf.f_bsize bsize_factor becomes zero. The following divisions become divide by zero! Thanks, Sripathi. > vs->v9statfs.f_type = vs->stbuf.f_type; > vs->v9statfs.f_bsize = vs->stbuf.f_bsize; > - vs->v9statfs.f_blocks = vs->stbuf.f_blocks; > - vs->v9statfs.f_bfree = vs->stbuf.f_bfree; > - vs->v9statfs.f_bavail = vs->stbuf.f_bavail; > + vs->v9statfs.f_bsize *= bsize_factor; > + vs->v9statfs.f_blocks = vs->stbuf.f_blocks/bsize_factor; > + vs->v9statfs.f_bfree = vs->stbuf.f_bfree/bsize_factor; > + vs->v9statfs.f_bavail = vs->stbuf.f_bavail/bsize_factor; > vs->v9statfs.f_files = vs->stbuf.f_files; > vs->v9statfs.f_ffree = vs->stbuf.f_ffree; > vs->v9statfs.fsid_val = (unsigned int) vs->stbuf.f_fsid.__val[0] | > diff --git a/hw/virtio-9p.h b/hw/virtio-9p.h > index 6b3d4a4..9264163 100644 > --- a/hw/virtio-9p.h > +++ b/hw/virtio-9p.h > @@ -72,6 +72,8 @@ enum p9_proto_version { > #define P9_NOFID (u32)(~0) > #define P9_MAXWELEM 16 > > +#define P9_IOHDRSZ 24 > + > typedef struct V9fsPDU V9fsPDU; > > struct V9fsPDU > @@ -156,6 +158,7 @@ typedef struct V9fsState > uint8_t *tag; > size_t config_size; > enum p9_proto_version proto_version; > + int32_t msize; > } V9fsState; > > typedef struct V9fsCreateState { > -- > 1.6.6.1 > >