Unfortunately, the command line options for btrfs send were misnamed. To
specify a base for an incremental snapshot transfer, the best choice is -i
for "incremental" (was: -p). To optionally add snapshots existing on the
receiver as clone sources, the best choice is -c (was: -i).
Compatibily note: -i option was broken anyway, which makes it less critical
reassigning it. For potential users of the old option style, we emit a fatal
warning if the -p is used.
Signed-off-by: Jan Schmidt <list.bt...@jan-o-sch.net>
Reviewed-by: Alexander Block <abloc...@googlemail.com>
---
cmds-send.c | 97 +++++++++++++++++++++++++++++++---------------------------
1 files changed, 52 insertions(+), 45 deletions(-)
diff --git a/cmds-send.c b/cmds-send.c
index 9b47e70..9db65e9 100644
--- a/cmds-send.c
+++ b/cmds-send.c
@@ -234,7 +234,7 @@ 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 base_root_id)
{
int ret;
pthread_t t_read;
@@ -286,7 +286,7 @@ 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 = base_root_id;
ret = ioctl(subvol_fd, BTRFS_IOC_SEND, &io_send);
if (ret) {
ret = -errno;
@@ -420,19 +420,20 @@ int cmd_send_start(int argc, char **argv)
struct btrfs_send send;
u32 i;
char *mount_root = NULL;
- char *snapshot_parent = NULL;
+ char *incremental_base = NULL;
u64 root_id;
- u64 parent_root_id = 0;
+ u64 base_root_id = 0;
+ int full_send = 1;
memset(&send, 0, sizeof(send));
send.dump_fd = fileno(stdout);
- while ((c = getopt(argc, argv, "vf:i:p:")) != -1) {
+ while ((c = getopt(argc, argv, "vf:i:p:r:")) != -1) {
switch (c) {
case 'v':
g_verbose++;
break;
- case 'i': {
+ case 'r':
subvol = realpath(optarg, NULL);
if (!subvol) {
ret = -errno;
@@ -455,19 +456,26 @@ int cmd_send_start(int argc, char **argv)
add_clone_source(&send, root_id);
free(subvol);
break;
- }
case 'f':
outname = optarg;
break;
- case 'p':
- snapshot_parent = realpath(optarg, NULL);
- if (!snapshot_parent) {
+ case 'i':
+ if (incremental_base) {
+ fprintf(stderr, "ERROR: you cannot have more
than one base for incremental send (-i)\n");
+ return 1;
+ }
+ incremental_base = realpath(optarg, NULL);
+ if (!incremental_base) {
ret = -errno;
fprintf(stderr, "ERROR: realpath %s failed. "
"%s\n", optarg, strerror(-ret));
goto out;
}
+ full_send = 0;
break;
+ case 'p':
+ fprintf(stderr, "ERROR: -p option was removed. use -i
instead\n");
+ return 1;
case '?':
default:
fprintf(stderr, "ERROR: send args invalid.\n");
@@ -504,17 +512,17 @@ int cmd_send_start(int argc, char **argv)
if (ret < 0)
goto out;
- if (snapshot_parent != NULL) {
+ if (incremental_base != NULL) {
ret = get_root_id(&send,
- get_subvol_name(&send, snapshot_parent),
- &parent_root_id);
+ get_subvol_name(&send, incremental_base),
+ &base_root_id);
if (ret < 0) {
fprintf(stderr, "ERROR: could not resolve root_id "
- "for %s\n", snapshot_parent);
+ "for %s\n", incremental_base);
goto out;
}
- add_clone_source(&send, parent_root_id);
+ add_clone_source(&send, base_root_id);
}
for (i = optind; i < argc; i++) {
@@ -573,10 +581,13 @@ int cmd_send_start(int argc, char **argv)
goto out;
}
- if (!parent_root_id) {
- ret = find_good_parent(&send, root_id, &parent_root_id);
- if (ret < 0)
- parent_root_id = 0;
+ if (!full_send && !base_root_id) {
+ ret = find_good_parent(&send, root_id, &base_root_id);
+ if (ret < 0) {
+ fprintf(stderr, "ERROR: parent determination
failed for %lld\n",
+ root_id);
+ goto out;
+ }
}
ret = is_subvol_ro(&send, subvol);
@@ -589,14 +600,15 @@ int cmd_send_start(int argc, char **argv)
goto out;
}
- ret = do_send(&send, root_id, parent_root_id);
+ ret = do_send(&send, root_id, base_root_id);
if (ret < 0)
goto out;
/* done with this subvol, so add it to the clone sources */
add_clone_source(&send, root_id);
- parent_root_id = 0;
+ base_root_id = 0;
+ full_send = 0;
free(subvol);
}
@@ -614,32 +626,27 @@ 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] [-i <base>] [-r <snap>] <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 '-i <incremental-base>'. If you know the snapshots"
+ "available on the receiving side, use '-r <snap>' (multiple times",
+ "where applicable). This allows 'btrfs send' to clone from these",
+ "snapshots. You must not specify these unless you guarantee they are",
+ "exactly in the same state on both sides. It is allowed to omit the",
+ "'-i <base>' option when specifying one or more '-r <snap>' options,",
+ "in which case 'btrfs send' will determine the base itself."
+ "\n",
+ "-v Enable verbose debug output. Each occurrency of",
+ " this option increases the verbose level more.",
+ "-i <base> Send an incremental stream between <incr-base> and",
+ " <subvol>.",
+ "-r <snap> This snapshot exists on the receiver exactly in the ",
+ " same state as on the sender. (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
};
--
1.7.1
--
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