@@ -80,7 +80,13 @@ static void usage(const char *name)
"\n"
"Block device options:\n"
" -r, --read-only export read-only\n"
-" -s, --snapshot use snapshot file\n"
+" -s, --snapshot use FILE as an external snapshot, create a temporary\n"
+" file with backing_file=FILE, redirect the write to\n"
+" the temporary one\n"
+" -l, --snapshot-load=PARAM\n"
+" load an internal snapshot inside FILE and export it\n"
+" as an read-only device, PARAM format is\n"
+" 'id=[ID],name=[NAME]'\n"
" -n, --nocache disable host cache\n"
" --cache=MODE set cache mode (none, writeback, ...)\n"
#ifdef CONFIG_LINUX_AIO
@@ -27,7 +27,13 @@ Export QEMU disk image using NBD protocol.
@item -P, --partition=@var{num}
only expose partition @var{num}
@item -s, --snapshot
- use snapshot file
+ use @var{filename} as an external snapshot, create a temporary
+ file with backing_file=@var{filename}, redirect the write to
+ the temporary one
+@item -l, --snapshot-load=@var{param}
+ load an internal snapshot inside @var{filename} and export it
+ as an read-only device, @var{param} format is
+ 'id=[ID],name=[NAME]'
@item -n, --nocache
@itemx --cache=@var{cache}
set cache mode to be used with the file. See the documentation of
Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> --- qemu-nbd.c | 8 +++++++- qemu-nbd.texi | 8 +++++++- 2 files changed, 14 insertions(+), 2 deletions(-)