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[1/3] block/ssh: Pull ssh_grow_file() from ssh_create()

Message ID 20180214204915.7980-2-mreitz@redhat.com
State New
Headers show
Series block/ssh: Add basic .bdrv_truncate() | expand

Commit Message

Max Reitz Feb. 14, 2018, 8:49 p.m. UTC 
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 <mreitz@redhat.com>
---
 block/ssh.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

Comments

Eric Blake Feb. 14, 2018, 9:08 p.m. UTC | #1 
On 02/14/2018 02:49 PM, Max Reitz wrote:
> 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 <mreitz@redhat.com>
> ---
>   block/ssh.c | 30 ++++++++++++++++++++++--------
>   1 file changed, 22 insertions(+), 8 deletions(-)
> 

> +++ 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' };

Could spell this 'char c[1] = "";', but you just did code motion.

Reviewed-by: Eric Blake <eblake@redhat.com>
diff mbox series

Patch

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;