btrfs-progs: dump-super: changes in options to specify superblocks

Some tools (check, select-super, dump-super) can use the alternate
superblocks, but the options are not consistent. To make it less
confusing, change the meaning of option -s in 'dump-super' to specify
the superblock copy, instead of taking the offset.

Though this is a change in UI, the old usage is detected and the result
would be the same, no breakage in existing scripts.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/Documentation/btrfs-inspect-internal.asciidoc b/Documentation/btrfs-inspect-internal.asciidoc
index 74f6dea..44615e7 100644 (file)
--- a/Documentation/btrfs-inspect-internal.asciidoc
+++ b/Documentation/btrfs-inspect-internal.asciidoc
@@ -30,25 +30,36 @@ Besides verifictaion of the filesystem signature, there are no other sanity
 checks. The superblock checksum status is reported, the device item and
 filesystem UUIDs are checked and reported.
 +
+NOTE: the meaning of option '-s' has changed in version 4.8 to be consistent
+with other tools to specify superblock copy rather the offset. The old way still
+works, but prints a warning. Please update your scripts to use '--bytenr'
+instead. The option '-i' has been deprecated.
++
 `Options`
 +
 -f|--full::::
 print full superblock information, including the system chunk array and backup roots
 -a|--all::::
-print information about all present superblock copies (cannot be used together with '-i' option)
--i <super_mirror>::::
-specify which mirror to print, valid values are 0, 1 and 2 and the superblock must be present on the device
+print information about all present superblock copies (cannot be used together
+with '-s' option)
+-i <super>::::
+(deprecated since 4.8, same behaviour as '--super')
+--bytenr <bytenr>::::
+specify offset to a superblock in a non-standard location at 'bytenr', useful
+for debugging (disables the '-f' option)
 +
-If there are multiple options specified, only the last one is applies.
+If there are multiple options specified, only the last one applies.
 +
 -F|--force::::
-attempt to print the superblock even if thre's no valid BTRFS signature found
+attempt to print the superblock even if thre's no valid BTRFS signature found,
+the result may be completely wrong if the data do not resemble a superblock
 +
-The result may be completely wrong if the data do not resemble a superblock.
+-s|--super <bytenr>::::
+(see compatibility note above)
 +
--s <bytenr>::::
-specify offset to a superblock in a non-standard location at 'bytenr', useful
-for debugging (disables the '-f' option)
+specify which mirror to print, valid values are 0, 1 and 2 and the superblock
+must be present on the device with a valid signature, can be used together with
+'--force'
 
 *dump-tree* [options] <device>::
 (replaces the standalone tool *btrfs-debug-tree*)

diff --git a/cmds-inspect-dump-super.c b/cmds-inspect-dump-super.c
index aab5075..0ae740a 100644 (file)
--- a/cmds-inspect-dump-super.c
+++ b/cmds-inspect-dump-super.c
@@ -458,11 +458,18 @@ static int load_and_dump_sb(char *filename, int fd, u64 sb_bytenr, int full,
 const char * const cmd_inspect_dump_super_usage[] = {
        "btrfs inspect-internal dump-super [options] device [device...]",
        "Dump superblock from a device in a textual form",
-       "-f|--full           print full superblock information",
-       "-a|--all            print information about all superblocks",
-       "-i <super_mirror>   specify which mirror to print out",
-       "-F|--force          attempt to dump superblocks with bad magic",
-       "-s <bytenr>         specify alternate superblock offset",
+       "-f|--full             print full superblock information, backup roots etc.",
+       "-a|--all              print information about all superblocks",
+       "-s|--super <super>    specify which copy to print out (values: 0, 1, 2)",
+       "-F|--force            attempt to dump superblocks with bad magic",
+       "--bytenr <offset>     specify alternate superblock offset",
+       "",
+       "Deprecated syntax:",
+       "-s <bytenr>           specify alternate superblock offset, values other than 0, 1, 2",
+       "                      will be interpreted as --bytenr for backward compatibility,",
+       "                      option renamed for consistency with other tools (eg. check)",
+       "-i <super>            specify which copy to print out (values: 0, 1, 2), now moved",
+       "                      to -s|--super",
        NULL
 };
 
@@ -484,6 +491,7 @@ int cmd_inspect_dump_super(int argc, char **argv)
                        {"all", no_argument, NULL, 'a'},
                        {"full", no_argument, NULL, 'f'},
                        {"force", no_argument, NULL, 'F'},
+                       {"super", required_argument, NULL, 's' },
                        {NULL, 0, NULL, 0}
                };
 
@@ -493,11 +501,13 @@ int cmd_inspect_dump_super(int argc, char **argv)
 
                switch (c) {
                case 'i':
+                       warning(
+                           "option -i is deprecated, please use -s or --super");
                        arg = arg_strtou64(optarg);
                        if (arg >= BTRFS_SUPER_MIRROR_MAX) {
                                error("super mirror too big: %llu >= %d",
                                        arg, BTRFS_SUPER_MIRROR_MAX);
-                               usage(cmd_inspect_dump_super_usage);
+                               return 1;
                        }
                        sb_bytenr = btrfs_sb_offset(arg);
                        break;
@@ -512,7 +522,15 @@ int cmd_inspect_dump_super(int argc, char **argv)
                        force = 1;
                        break;
                case 's':
-                       sb_bytenr = arg_strtou64(optarg);
+                       arg = arg_strtou64(optarg);
+                       if (BTRFS_SUPER_MIRROR_MAX <= arg) {
+                               warning(
+               "deprecated use of -s <bytenr> with %llu, assuming --bytenr",
+                                               (unsigned long long)arg);
+                               sb_bytenr = arg;
+                       } else {
+                               sb_bytenr = btrfs_sb_offset(arg);
+                       }
                        all = 0;
                        break;
                default: