nvme: Open device exclusive for write command

Commit 2100609ddefb ("nvme: open namespace exclusive by default")
tried to make the write command a bit safer by asking to open the
device exclusive. Because the commit got reverted let's add the main
change back which is to use O_EXCL for write commands on default.

Signed-off-by: Daniel Wagner <dwagner@suse.de>

diff --git a/nvme.c b/nvme.c
index 35e0b121b20fc9fb53413eb940f76c9b7bf380e2..9b5b6d15dc15f89d43b5fe62bf5cc2ce68d55f8e 100644 (file)
--- a/nvme.c
+++ b/nvme.c
@@ -6059,6 +6059,7 @@ static int submit_io(int opcode, char *command, const char *desc,
                "checked as part of end-to-end data protection processing";
        const char *storage_tag = "storage tag, CDW2 and CDW3 (00:47) bits "\
                "(for end to end PI)";
+       const char *force = "The \"I know what I'm doing\" flag, do not enforce exclusive access for write";
 
        struct config {
                __u32 namespace_id;
@@ -6082,6 +6083,7 @@ static int submit_io(int opcode, char *command, const char *desc,
                int   show;
                int   dry_run;
                int   latency;
+               int   force;
        };
 
        struct config cfg = {
@@ -6098,6 +6100,7 @@ static int submit_io(int opcode, char *command, const char *desc,
                .app_tag                = 0,
                .storage_tag_check      = 0,
                .storage_tag            = 0,
+               .force                  = 0,
        };
 
        OPT_ARGS(opts) = {
@@ -6122,12 +6125,28 @@ static int submit_io(int opcode, char *command, const char *desc,
                OPT_FLAG("show-command",      'v', &cfg.show,              show),
                OPT_FLAG("dry-run",           'w', &cfg.dry_run,           dry),
                OPT_FLAG("latency",           't', &cfg.latency,           latency),
+               OPT_FLAG("force",               0, &cfg.force,             force),
                OPT_END()
        };
 
-       err = fd = parse_and_open(argc, argv, desc, opts);
-       if (fd < 0)
-               goto ret;
+       if (opcode != nvme_cmd_write) {
+               err = fd = parse_and_open(argc, argv, desc, opts);
+               if (fd < 0)
+                       goto ret;
+       } else {
+               err = fd = open_exclusive(argc, argv, cfg.force);
+               if (errno == EBUSY) {
+                       fprintf(stderr, "Failed to open %s.\n",
+                               basename(argv[optind]));
+                       fprintf(stderr,
+                               "Namespace is currently busy.\n");
+                       if (!cfg.force)
+                               fprintf(stderr,
+                               "Use the force [--force] option to ignore that.\n");
+               } else {
+                       argconfig_print_help(desc, opts);
+               }
+       }
 
        if (!cfg.namespace_id) {
                err = nvme_get_nsid(fd, &cfg.namespace_id);