Add '-s <sb_bytenr>' option to show superblock at given bytenr.
This is very useful to debug non-standard btrfs, like debuging the
1st stage btrfs of btrfs-convert.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
Documentation/btrfs-show-super.asciidoc | 5 +++++
btrfs-show-super.c | 7 ++++++-
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/Documentation/btrfs-show-super.asciidoc b/Documentation/btrfs-show-super.asciidoc
index 1646be3..3480a3d 100644
--- a/Documentation/btrfs-show-super.asciidoc
+++ b/Documentation/btrfs-show-super.asciidoc
@@ -40,6 +40,11 @@ If several '-i <super_mirror>' are given, only the last one is valid.
Attempt to print the superblock even if no superblock magic is found. May end
badly.
+-s <super_bytenr>::
+Specifiy the superblock bytenr.
++
+Used for debug purpose. Disable '-f' option.
+
EXIT STATUS
-----------
*btrfs-show-super* will return 0 if no error happened.
diff --git a/btrfs-show-super.c b/btrfs-show-super.c
index 27414c8..7b499e4 100644
--- a/btrfs-show-super.c
+++ b/btrfs-show-super.c
@@ -48,6 +48,7 @@ static void print_usage(void)
fprintf(stderr, "\t-a : print information of all superblocks\n");
fprintf(stderr, "\t-i <super_mirror> : specify which mirror to print out\n");
fprintf(stderr, "\t-F : attempt to dump superblocks with bad magic\n");
+ fprintf(stderr, "\t-s <bytenr> : specify the superblock bytenr\n");
fprintf(stderr, "%s\n", PACKAGE_STRING);
}
@@ -63,7 +64,7 @@ int main(int argc, char **argv)
u64 arg;
u64 sb_bytenr = btrfs_sb_offset(0);
- while ((opt = getopt(argc, argv, "fFai:")) != -1) {
+ while ((opt = getopt(argc, argv, "fFai:s:")) != -1) {
switch (opt) {
case 'i':
arg = arg_strtou64(optarg);
@@ -86,6 +87,10 @@ int main(int argc, char **argv)
case 'F':
force = 1;
break;
+ case 's':
+ sb_bytenr = arg_strtou64(optarg);
+ all = 0;
+ break;
default:
print_usage();
exit(1);
--
2.6.2
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