From: "Dr. David Alan Gilbert" <[email protected]> virtiofsd incorrectly assumed a fixed set of header layout in the virt queue; assuming that the fuse and write headers were conveniently separated from the data; the spec doesn't allow us to take that convenience, so fix it up to deal with it the hard way.
Signed-off-by: Dr. David Alan Gilbert <[email protected]> --- tools/virtiofsd/fuse_virtio.c | 84 ++++++++++++++++++++++++++--------- 1 file changed, 63 insertions(+), 21 deletions(-) diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index 523ee64fb7..55e2e057ec 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -129,18 +129,55 @@ static void fv_panic(VuDev *dev, const char *err) * Copy from an iovec into a fuse_buf (memory only) * Caller must ensure there is space */ -static void copy_from_iov(struct fuse_buf *buf, size_t out_num, - const struct iovec *out_sg) +static size_t copy_from_iov(struct fuse_buf *buf, size_t out_num, + const struct iovec *out_sg, + size_t max) { void *dest = buf->mem; + size_t copied = 0; - while (out_num) { + while (out_num && max) { size_t onelen = out_sg->iov_len; + onelen = MIN(onelen, max); memcpy(dest, out_sg->iov_base, onelen); dest += onelen; + copied += onelen; out_sg++; out_num--; + max -= onelen; } + + return copied; +} + +/* + * Skip 'skip' bytes in the iov; 'sg_1stindex' is set as + * the index for the 1st iovec to read data from, and + * 'sg_1stskip' is the number of bytes to skip in that entry. + * + * Returns True if there are at least 'skip' bytes in the iovec + * + */ +static bool skip_iov(const struct iovec *sg, size_t sg_size, + size_t skip, + size_t *sg_1stindex, size_t *sg_1stskip) +{ + size_t vec; + + for (vec = 0; vec < sg_size; vec++) { + if (sg[vec].iov_len > skip) { + *sg_1stskip = skip; + *sg_1stindex = vec; + + return true; + } + + skip -= sg[vec].iov_len; + } + + *sg_1stindex = vec; + *sg_1stskip = 0; + return skip == 0; } /* @@ -505,14 +542,14 @@ static void fv_queue_worker(gpointer data, gpointer user_data) elem->index); assert(0); /* TODO */ } - /* Copy just the first element and look at it */ - copy_from_iov(&fbuf, 1, out_sg); + /* Copy just the fuse_in_header and look at it */ + copy_from_iov(&fbuf, out_num, out_sg, + sizeof(struct fuse_in_header)); pbufv = NULL; /* Compiler thinks an unitialised path */ - if (out_num > 2 && - out_sg[0].iov_len == sizeof(struct fuse_in_header) && - ((struct fuse_in_header *)fbuf.mem)->opcode == FUSE_WRITE && - out_sg[1].iov_len == sizeof(struct fuse_write_in)) { + if (((struct fuse_in_header *)fbuf.mem)->opcode == FUSE_WRITE && + out_len >= (sizeof(struct fuse_in_header) + + sizeof(struct fuse_write_in))) { /* * For a write we don't actually need to copy the * data, we can just do it straight out of guest memory @@ -521,15 +558,13 @@ static void fv_queue_worker(gpointer data, gpointer user_data) */ fuse_log(FUSE_LOG_DEBUG, "%s: Write special case\n", __func__); - /* copy the fuse_write_in header afte rthe fuse_in_header */ - fbuf.mem += out_sg->iov_len; - copy_from_iov(&fbuf, 1, out_sg + 1); - fbuf.mem -= out_sg->iov_len; - fbuf.size = out_sg[0].iov_len + out_sg[1].iov_len; + fbuf.size = copy_from_iov(&fbuf, out_num, out_sg, + sizeof(struct fuse_in_header) + + sizeof(struct fuse_write_in)); /* Allocate the bufv, with space for the rest of the iov */ pbufv = malloc(sizeof(struct fuse_bufvec) + - sizeof(struct fuse_buf) * (out_num - 2)); + sizeof(struct fuse_buf) * out_num); if (!pbufv) { fuse_log(FUSE_LOG_ERR, "%s: pbufv malloc failed\n", __func__); @@ -540,24 +575,31 @@ static void fv_queue_worker(gpointer data, gpointer user_data) pbufv->count = 1; pbufv->buf[0] = fbuf; - size_t iovindex, pbufvindex; - iovindex = 2; /* 2 headers, separate iovs */ + size_t iovindex, pbufvindex, skip; pbufvindex = 1; /* 2 headers, 1 fusebuf */ + skip_iov(out_sg, out_num, + sizeof(struct fuse_in_header) + + sizeof(struct fuse_write_in), + &iovindex, &skip); + for (; iovindex < out_num; iovindex++, pbufvindex++) { pbufv->count++; pbufv->buf[pbufvindex].pos = ~0; /* Dummy */ pbufv->buf[pbufvindex].flags = 0; pbufv->buf[pbufvindex].mem = out_sg[iovindex].iov_base; pbufv->buf[pbufvindex].size = out_sg[iovindex].iov_len; + + if (skip) { + pbufv->buf[pbufvindex].mem += skip; + pbufv->buf[pbufvindex].size -= skip; + skip = 0; + } } } else { /* Normal (non fast write) path */ - /* Copy the rest of the buffer */ - fbuf.mem += out_sg->iov_len; - copy_from_iov(&fbuf, out_num - 1, out_sg + 1); - fbuf.mem -= out_sg->iov_len; + copy_from_iov(&fbuf, out_num, out_sg, se->bufsize); fbuf.size = out_len; /* TODO! Endianness of header */ -- 2.29.2 _______________________________________________ Virtio-fs mailing list [email protected] https://listman.redhat.com/mailman/listinfo/virtio-fs
