Btrfs-progs: correcting misnamed parameter options for btrfs send

Unfortunately, the command line options for btrfs send were misnamed. The
-i option should not be used to give "clone sources", we'll be using -c
instead.

Compatibily note: -i option was broken anyway, which makes it less critical
renaming it. For potential users of the old option style, we emit a fatal
warning if the -i option is used.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

diff --git a/cmds-send.c b/cmds-send.c
index 5607f2a..d2f7691 100644 (file)
--- a/cmds-send.c
+++ b/cmds-send.c
@@ -236,7 +236,7 @@ out:
        return ERR_PTR(ret);
 }
 
-static int do_send(struct btrfs_send *send, u64 root_id, u64 parent_root)
+static int do_send(struct btrfs_send *send, u64 root_id, u64 parent_root_id)
 {
        int ret;
        pthread_t t_read;
@@ -289,7 +289,7 @@ static int do_send(struct btrfs_send *send, u64 root_id, u64 parent_root)
 
        io_send.clone_sources = (__u64*)send->clone_sources;
        io_send.clone_sources_count = send->clone_sources_count;
-       io_send.parent_root = parent_root;
+       io_send.parent_root = parent_root_id;
        ret = ioctl(subvol_fd, BTRFS_IOC_SEND, &io_send);
        if (ret) {
                ret = -errno;
@@ -426,6 +426,7 @@ int cmd_send_start(int argc, char **argv)
        char *snapshot_parent = NULL;
        u64 root_id;
        u64 parent_root_id = 0;
+       int full_send = 1;
 
        memset(&send, 0, sizeof(send));
        send.dump_fd = fileno(stdout);
@@ -435,12 +436,12 @@ int cmd_send_start(int argc, char **argv)
                return 1;
        }
 
-       while ((c = getopt(argc, argv, "vf:i:p:")) != -1) {
+       while ((c = getopt(argc, argv, "vc:f:i:p:")) != -1) {
                switch (c) {
                case 'v':
                        g_verbose++;
                        break;
-               case 'i': {
+               case 'c':
                        subvol = realpath(optarg, NULL);
                        if (!subvol) {
                                ret = -errno;
@@ -462,12 +463,16 @@ int cmd_send_start(int argc, char **argv)
                        }
                        add_clone_source(&send, root_id);
                        free(subvol);
+                       full_send = 0;
                        break;
-               }
                case 'f':
                        outname = optarg;
                        break;
                case 'p':
+                       if (snapshot_parent) {
+                               fprintf(stderr, "ERROR: you cannot have more than one parent (-p)\n");
+                               return 1;
+                       }
                        snapshot_parent = realpath(optarg, NULL);
                        if (!snapshot_parent) {
                                ret = -errno;
@@ -475,7 +480,12 @@ int cmd_send_start(int argc, char **argv)
                                                "%s\n", optarg, strerror(-ret));
                                goto out;
                        }
+                       full_send = 0;
                        break;
+               case 'i':
+                       fprintf(stderr,
+                               "ERROR: -i was removed, use -c instead\n");
+                       return 1;
                case '?':
                default:
                        fprintf(stderr, "ERROR: send args invalid.\n");
@@ -581,10 +591,13 @@ int cmd_send_start(int argc, char **argv)
                        goto out;
                }
 
-               if (!parent_root_id) {
+               if (!full_send && !parent_root_id) {
                        ret = find_good_parent(&send, root_id, &parent_root_id);
-                       if (ret < 0)
-                               parent_root_id = 0;
+                       if (ret < 0) {
+                               fprintf(stderr, "ERROR: parent determination failed for %lld\n",
+                                       root_id);
+                               goto out;
+                       }
                }
 
                ret = is_subvol_ro(&send, subvol);
@@ -605,6 +618,7 @@ int cmd_send_start(int argc, char **argv)
                add_clone_source(&send, root_id);
 
                parent_root_id = 0;
+               full_send = 0;
                free(subvol);
        }
 
@@ -622,32 +636,28 @@ static const char * const send_cmd_group_usage[] = {
 };
 
 static const char * const cmd_send_usage[] = {
-       "btrfs send [-v] [-i <subvol>] [-p <parent>] <subvol>",
+       "btrfs send [-v] [-p <parent>] [-c <clone-src>] <subvol>",
        "Send the subvolume to stdout.",
        "Sends the subvolume specified by <subvol> to stdout.",
-       "By default, this will send the whole subvolume. To do",
-       "an incremental send, one or multiple '-i <clone_source>'",
-       "arguments have to be specified. A 'clone source' is",
-       "a subvolume that is known to exist on the receiving",
-       "side in exactly the same state as on the sending side.\n",
-       "Normally, a good snapshot parent is searched automatically",
-       "in the list of 'clone sources'. To override this, use",
-       "'-p <parent>' to manually specify a snapshot parent.",
-       "A manually specified snapshot parent is also regarded",
-       "as 'clone source'.\n",
-       "-v               Enable verbose debug output. Each",
-       "                 occurrency of this option increases the",
-       "                 verbose level more.",
-       "-i <subvol>      Informs btrfs send that this subvolume,",
-       "                 can be taken as 'clone source'. This can",
-       "                 be used for incremental sends.",
-       "-p <subvol>      Disable automatic snaphot parent",
-       "                 determination and use <subvol> as parent.",
-       "                 This subvolume is also added to the list",
-       "                 of 'clone sources' (see -i).",
-       "-f <outfile>     Output is normally written to stdout.",
-       "                 To write to a file, use this option.",
-       "                 An alternative would be to use pipes.",
+       "By default, this will send the whole subvolume. To do an incremental",
+       "send, use '-p <parent>'. If you want to allow btrfs to clone from",
+       "any additional local snapshots, use -c <clone-src> (multiple times",
+       "where applicable). You must not specify clone sources unless you",
+       "guarantee that these snapshots are exactly in the same state on both",
+       "sides, the sender and the receiver. It is allowed to omit the",
+       "'-p <parent>' option when '-c <clone-src>' options are given, in",
+       "which case 'btrfs send' will determine a suitable parent among the",
+       "clone sources itself.",
+       "\n",
+       "-v               Enable verbose debug output. Each occurrency of",
+       "                 this option increases the verbose level more.",
+       "-p <parent>      Send an incremental stream from <parent> to",
+       "                 <subvol>.",
+       "-c <clone-src>   Use this snapshot as a clone source for an ",
+       "                 incremental send (multiple allowed)",
+       "-f <outfile>     Output is normally written to stdout. To write to",
+       "                 a file, use this option. An alternative would be to",
+       "                 use pipes.",
        NULL
 };