Commit fa0eb5c5 authored by Greg Kurz's avatar Greg Kurz
Browse files

9pfs: fix offset error in v9fs_xattr_read() 



The current code tries to copy `read_count' bytes starting at offset
`offset' from a `read_count`-sized iovec. This causes v9fs_pack() to
fail with ENOBUFS.

Since the PDU iovec is already partially filled with `offset' bytes,
let's skip them when creating `qiov_full' and have v9fs_pack() to
copy the whole of it. Moreover, this is consistent with the other
places where v9fs_init_qiov_from_pdu() is called.

This fixes commit "bcb8998f 9pfs: call v9fs_init_qiov_from_pdu
before v9fs_pack".

Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Reviewed-by: default avatarStefano Stabellini <sstabellini@kernel.org>
parent 6fe76acc

hw/9pfs/9p.c

+3 −3
Original line number Diff line number Diff line
@@ -1655,7 +1655,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu, 
    if (is_write) {

        pdu->s->transport->init_out_iov_from_pdu(pdu, &iov, &niov);

    } else {

        pdu->s->transport->init_in_iov_from_pdu(pdu, &iov, &niov, size);

        pdu->s->transport->init_in_iov_from_pdu(pdu, &iov, &niov, size + skip);

    }



    qemu_iovec_init_external(&elem, iov, niov);
@@ -1685,8 +1685,8 @@ static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp, 
    }

    offset += err;



    v9fs_init_qiov_from_pdu(&qiov_full, pdu, 0, read_count, false);

    err = v9fs_pack(qiov_full.iov, qiov_full.niov, offset,

    v9fs_init_qiov_from_pdu(&qiov_full, pdu, offset, read_count, false);

    err = v9fs_pack(qiov_full.iov, qiov_full.niov, 0,

                    ((char *)fidp->fs.xattr.value) + off,

                    read_count);

    qemu_iovec_destroy(&qiov_full);