debugfs: clarify man page for the -b and -s options

Addresses-Debian-Bug: #766379

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/debugfs/debugfs.8.in b/debugfs/debugfs.8.in
index 7c7cdcc..e85034a 100644 (file)
--- a/debugfs/debugfs.8.in
+++ b/debugfs/debugfs.8.in
@@ -94,8 +94,10 @@ should be used when reading blocks not found in the ext2 image file.
 This includes data, directory, and indirect blocks.
 .TP
 .I -b blocksize
-Forces the use of the given block size for the file system, rather than
-detecting the correct block size as normal.
+Forces the use of the given block size (in bytes) for the file system,
+rather than detecting the correct block size automatically.  (This
+option is rarely needed; it is used primarily when the file system is
+extremely badly damaged/corrupted.)
 .TP
 .I -s superblock
 Causes the file system superblock to be read from the given block
@@ -104,7 +106,9 @@ number, instead of using the primary superblock (located at an offset of
 .I -s
 option, you must also provide the blocksize of the filesystem via the
 .I -b
-option.
+option.   (This
+option is rarely needed; it is used primarily when the file system is
+extremely badly damaged/corrupted.)
 .TP
 .I -f cmd_file
 Causes