If we ever want to offer even rudimentary truncation functionality for ssh, we should put the respective code into a reusable function.
Signed-off-by: Max Reitz <mre...@redhat.com> --- block/ssh.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) diff --git a/block/ssh.c b/block/ssh.c index b63addcf94..964e55f7fe 100644 --- a/block/ssh.c +++ b/block/ssh.c @@ -803,6 +803,26 @@ static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags, return ret; } +static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp) +{ + ssize_t ret; + char c[1] = { '\0' }; + + /* offset must be strictly greater than the current size so we do + * not overwrite anything */ + assert(offset > 0 && offset > s->attrs.filesize); + + libssh2_sftp_seek64(s->sftp_handle, offset - 1); + ret = libssh2_sftp_write(s->sftp_handle, c, 1); + if (ret < 0) { + sftp_error_setg(errp, s, "Failed to grow file"); + return -EIO; + } + + s->attrs.filesize = offset; + return 0; +} + static QemuOptsList ssh_create_opts = { .name = "ssh-create-opts", .head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head), @@ -822,8 +842,6 @@ static int ssh_create(const char *filename, QemuOpts *opts, Error **errp) int64_t total_size = 0; QDict *uri_options = NULL; BDRVSSHState s; - ssize_t r2; - char c[1] = { '\0' }; ssh_state_init(&s); @@ -849,14 +867,10 @@ static int ssh_create(const char *filename, QemuOpts *opts, Error **errp) } if (total_size > 0) { - libssh2_sftp_seek64(s.sftp_handle, total_size-1); - r2 = libssh2_sftp_write(s.sftp_handle, c, 1); - if (r2 < 0) { - sftp_error_setg(errp, &s, "truncate failed"); - ret = -EINVAL; + ret = ssh_grow_file(&s, total_size, errp); + if (ret < 0) { goto out; } - s.attrs.filesize = total_size; } ret = 0; -- 2.14.3