dumpe2fs: fix output for flex_bg bitmap offsets

When running dumpe2fs on a filesystem formatted with flex_bg, it
prints out the relative offsets for the bitmaps and inode table
badly on 64-bit systems, because the offset is computed as a
large positive number instead of being a negative numer (which
will not be printed at all):

Group 1: (Blocks 0x8000-0xffff) [INODE_UNINIT, ITABLE_ZEROED]
 Block bitmap at 0x0102 (+4294934786), Inode bitmap at 0x0202 (+4294935042)
 Inode table at 0x037e-0x03fa (+4294935422)

This commit prints out the relative offsets for flex_bg
groups as the offset within the reported group.  This makes it
more clear where the metadata is located, rather than simply
printing some large negative number.

Group 1: (Blocks 0x8000-0xffff) [INODE_UNINIT, ITABLE_ZEROED]
 Block bitmap at 0x0102 (bg #0 +258), Inode bitmap at 0x0202 (bg #0 +514)
 Inode table at 0x037e-0x03fa (bg #0 +894)

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/misc/dumpe2fs.c b/misc/dumpe2fs.c
index a70cc4e..5e0a8a2 100644 (file)
--- a/misc/dumpe2fs.c
+++ b/misc/dumpe2fs.c
@@ -126,10 +126,24 @@ static void print_bg_opts(ext2_filsys fs, dgrp_t i)
        fputc('\n', stdout);
 }
 
+static void print_bg_rel_offset(ext2_filsys fs, blk64_t block, int itable,
+                               blk64_t first_block, blk64_t last_block)
+{
+       if ((block >= first_block) && (block <= last_block)) {
+               if (itable && block == first_block)
+                       return;
+               printf(" (+%u)", (unsigned)(block - first_block));
+       } else if (fs->super->s_feature_incompat &
+                  EXT4_FEATURE_INCOMPAT_FLEX_BG) {
+               dgrp_t flex_grp = ext2fs_group_of_blk(fs, block);
+               printf(" (bg #%u + %u)", flex_grp,
+                      (unsigned)(block-ext2fs_group_first_block(fs,flex_grp)));
+       }
+}
+
 static void list_desc (ext2_filsys fs)
 {
        unsigned long i;
-       long diff;
        blk_t   first_block, last_block;
        blk_t   super_blk, old_desc_blk, new_desc_blk;
        char *block_bitmap=NULL, *inode_bitmap=NULL;
@@ -199,21 +213,21 @@ static void list_desc (ext2_filsys fs)
                        fputc('\n', stdout);
                fputs(_("  Block bitmap at "), stdout);
                print_number(fs->group_desc[i].bg_block_bitmap);
-               diff = fs->group_desc[i].bg_block_bitmap - first_block;
-               if (diff >= 0)
-                       printf(" (+%ld)", diff);
+               print_bg_rel_offset(fs, fs->group_desc[i].bg_block_bitmap, 0,
+                                   first_block, last_block);
+
                fputs(_(", Inode bitmap at "), stdout);
                print_number(fs->group_desc[i].bg_inode_bitmap);
-               diff = fs->group_desc[i].bg_inode_bitmap - first_block;
-               if (diff >= 0)
-                       printf(" (+%ld)", diff);
+               print_bg_rel_offset(fs, fs->group_desc[i].bg_inode_bitmap, 0,
+                                   first_block, last_block);
+
                fputs(_("\n  Inode table at "), stdout);
                print_range(fs->group_desc[i].bg_inode_table,
                            fs->group_desc[i].bg_inode_table +
                            inode_blocks_per_group - 1);
-               diff = fs->group_desc[i].bg_inode_table - first_block;
-               if (diff > 0)
-                       printf(" (+%ld)", diff);
+               print_bg_rel_offset(fs, fs->group_desc[i].bg_inode_table, 1,
+                                   first_block, last_block);
+
                printf (_("\n  %u free blocks, %u free inodes, "
                          "%u directories%s"),
                        fs->group_desc[i].bg_free_blocks_count,