From 30065d142443981924786da72828ba683da35e8f Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Tue, 26 Mar 2019 13:40:43 -0500 Subject: [PATCH] qemu-img: Gracefully shutdown when map can't finish Trying 'qemu-img map -f raw nbd://localhost:10809' causes the NBD server to output a scary message: qemu-nbd: Disconnect client, due to: Failed to read request: Unexpected end-of-file before all bytes were read This is because the NBD client, being remote, has no way to expose a human-readable map (the --output=json data is fine, however). But because we exit(1) right after the message, causing the client to bypass all block cleanup, the server sees the abrupt exit and warns, whereas it would be silent had the client had a chance to send NBD_CMD_DISC. Other protocols may have similar cleanup issues, where failure to blk_unref() could cause unintended effects. Signed-off-by: Eric Blake Message-Id: <20190326184043.7544-1-eblake@redhat.com> Reviewed-by: John Snow Reviewed-by: Kevin Wolf --- qemu-img.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 03a9a10dec..76a961df82 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -2736,14 +2736,14 @@ static int img_info(int argc, char **argv) return 0; } -static void dump_map_entry(OutputFormat output_format, MapEntry *e, - MapEntry *next) +static int dump_map_entry(OutputFormat output_format, MapEntry *e, + MapEntry *next) { switch (output_format) { case OFORMAT_HUMAN: if (e->data && !e->has_offset) { error_report("File contains external, encrypted or compressed clusters."); - exit(1); + return -1; } if (e->data && !e->zero) { printf("%#-16"PRIx64"%#-16"PRIx64"%#-16"PRIx64"%s\n", @@ -2776,6 +2776,7 @@ static void dump_map_entry(OutputFormat output_format, MapEntry *e, } break; } + return 0; } static int get_block_status(BlockDriverState *bs, int64_t offset, @@ -2968,12 +2969,15 @@ static int img_map(int argc, char **argv) } if (curr.length > 0) { - dump_map_entry(output_format, &curr, &next); + ret = dump_map_entry(output_format, &curr, &next); + if (ret < 0) { + goto out; + } } curr = next; } - dump_map_entry(output_format, &curr, NULL); + ret = dump_map_entry(output_format, &curr, NULL); out: blk_unref(blk);