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Re: [PATCH 039/104] virtiofsd: Plumb fuse_bufvec through to do_write_buf
From: |
Masayoshi Mizuma |
Subject: |
Re: [PATCH 039/104] virtiofsd: Plumb fuse_bufvec through to do_write_buf |
Date: |
Fri, 17 Jan 2020 16:01:49 -0500 |
On Thu, Dec 12, 2019 at 04:37:59PM +0000, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
>
> Let fuse_session_process_buf_int take a fuse_bufvec * instead of a
> fuse_buf; and then through to do_write_buf - where in the best
> case it can pass that straight through to op.write_buf without copying
> (other than skipping a header).
>
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> tools/virtiofsd/fuse_i.h | 2 +-
> tools/virtiofsd/fuse_lowlevel.c | 61 ++++++++++++++++++++++-----------
> tools/virtiofsd/fuse_virtio.c | 3 +-
> 3 files changed, 44 insertions(+), 22 deletions(-)
>
> diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
> index cb1ca70ffa..d0679508cd 100644
> --- a/tools/virtiofsd/fuse_i.h
> +++ b/tools/virtiofsd/fuse_i.h
> @@ -119,7 +119,7 @@ int fuse_send_reply_iov_nofree(fuse_req_t req, int error,
> struct iovec *iov,
> void fuse_free_req(fuse_req_t req);
>
> void fuse_session_process_buf_int(struct fuse_session *se,
> - const struct fuse_buf *buf,
> + struct fuse_bufvec *bufv,
> struct fuse_chan *ch);
>
>
> diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
> index bea092b454..7d33bbf539 100644
> --- a/tools/virtiofsd/fuse_lowlevel.c
> +++ b/tools/virtiofsd/fuse_lowlevel.c
> @@ -1006,11 +1006,12 @@ static void do_write(fuse_req_t req, fuse_ino_t
> nodeid, const void *inarg)
> }
>
> static void do_write_buf(fuse_req_t req, fuse_ino_t nodeid, const void
> *inarg,
> - const struct fuse_buf *ibuf)
> + struct fuse_bufvec *ibufv)
> {
> struct fuse_session *se = req->se;
> - struct fuse_bufvec bufv = {
> - .buf[0] = *ibuf,
> + struct fuse_bufvec *pbufv = ibufv;
> + struct fuse_bufvec tmpbufv = {
> + .buf[0] = ibufv->buf[0],
> .count = 1,
> };
> struct fuse_write_in *arg = (struct fuse_write_in *)inarg;
> @@ -1020,22 +1021,31 @@ static void do_write_buf(fuse_req_t req, fuse_ino_t
> nodeid, const void *inarg,
> fi.fh = arg->fh;
> fi.writepage = arg->write_flags & FUSE_WRITE_CACHE;
>
> - fi.lock_owner = arg->lock_owner;
> - fi.flags = arg->flags;
> - if (!(bufv.buf[0].flags & FUSE_BUF_IS_FD)) {
> - bufv.buf[0].mem = PARAM(arg);
> - }
> -
> - bufv.buf[0].size -=
> - sizeof(struct fuse_in_header) + sizeof(struct fuse_write_in);
> - if (bufv.buf[0].size < arg->size) {
> - fuse_log(FUSE_LOG_ERR, "fuse: do_write_buf: buffer size too
> small\n");
> - fuse_reply_err(req, EIO);
> - return;
> + if (ibufv->count == 1) {
> + fi.lock_owner = arg->lock_owner;
> + fi.flags = arg->flags;
> + if (!(tmpbufv.buf[0].flags & FUSE_BUF_IS_FD)) {
> + tmpbufv.buf[0].mem = PARAM(arg);
> + }
> + tmpbufv.buf[0].size -=
> + sizeof(struct fuse_in_header) + sizeof(struct fuse_write_in);
> + if (tmpbufv.buf[0].size < arg->size) {
> + fuse_log(FUSE_LOG_ERR,
> + "fuse: do_write_buf: buffer size too small\n");
> + fuse_reply_err(req, EIO);
> + return;
> + }
> + tmpbufv.buf[0].size = arg->size;
> + pbufv = &tmpbufv;
> + } else {
> + /*
> + * Input bufv contains the headers in the first element
> + * and the data in the rest, we need to skip that first element
> + */
> + ibufv->buf[0].size = 0;
> }
> - bufv.buf[0].size = arg->size;
>
> - se->op.write_buf(req, nodeid, &bufv, arg->offset, &fi);
> + se->op.write_buf(req, nodeid, pbufv, arg->offset, &fi);
> }
>
> static void do_flush(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
> @@ -2027,13 +2037,24 @@ static const char *opname(enum fuse_opcode opcode)
> void fuse_session_process_buf(struct fuse_session *se,
> const struct fuse_buf *buf)
> {
> - fuse_session_process_buf_int(se, buf, NULL);
> + struct fuse_bufvec bufv = { .buf[0] = *buf, .count = 1 };
> + fuse_session_process_buf_int(se, &bufv, NULL);
> }
>
> +/*
> + * Restriction:
> + * bufv is normally a single entry buffer, except for a write
> + * where (if it's in memory) then the bufv may be multiple entries,
> + * where the first entry contains all headers and subsequent entries
> + * contain data
> + * bufv shall not use any offsets etc to make the data anything
> + * other than contiguous starting from 0.
> + */
> void fuse_session_process_buf_int(struct fuse_session *se,
> - const struct fuse_buf *buf,
> + struct fuse_bufvec *bufv,
> struct fuse_chan *ch)
> {
> + const struct fuse_buf *buf = bufv->buf;
> struct fuse_in_header *in;
> const void *inarg;
> struct fuse_req *req;
> @@ -2111,7 +2132,7 @@ void fuse_session_process_buf_int(struct fuse_session
> *se,
>
> inarg = (void *)&in[1];
> if (in->opcode == FUSE_WRITE && se->op.write_buf) {
> - do_write_buf(req, in->nodeid, inarg, buf);
> + do_write_buf(req, in->nodeid, inarg, bufv);
> } else {
> fuse_ll_ops[in->opcode].func(req, in->nodeid, inarg);
> }
> diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
> index fa6e53e7d0..99c877ea2e 100644
> --- a/tools/virtiofsd/fuse_virtio.c
> +++ b/tools/virtiofsd/fuse_virtio.c
> @@ -499,7 +499,8 @@ static void *fv_queue_thread(void *opaque)
> /* TODO! Endianness of header */
>
> /* TODO: Add checks for fuse_session_exited */
> - fuse_session_process_buf_int(se, &fbuf, &ch);
> + struct fuse_bufvec bufv = { .buf[0] = fbuf, .count = 1 };
> + fuse_session_process_buf_int(se, &bufv, &ch);
>
> if (!qi->reply_sent) {
> fuse_log(FUSE_LOG_DEBUG, "%s: elem %d no reply sent\n",
Looks good to me.
Reviewed-by: Masayoshi Mizuma <address@hidden>
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