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Re: [Qemu-devel] qemu:virtio-9p: [RFC] [PATCH 01/02] Send iounit to clie
From: |
Sripathi Kodi |
Subject: |
Re: [Qemu-devel] qemu:virtio-9p: [RFC] [PATCH 01/02] Send iounit to client for read/write operations |
Date: |
Fri, 4 Jun 2010 12:21:17 +0530 |
On Tue, 1 Jun 2010 19:47:14 +0530
"M. Mohan Kumar" <address@hidden> 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 <address@hidden>
> ---
> 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
>
>