[Bug 794043] Re: mkdosfs incorrectly calculates sector total

[Rolf Leggewie]

Maverick has long since stopped to receive any updates. Marking the
Maverick task for this ticket as "Won't Fix".

** Changed in: dosfstools (Ubuntu Maverick)
       Status: New => Won't Fix

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https://bugs.launchpad.net/bugs/794043

Title:
  mkdosfs incorrectly calculates sector total

Status in “dosfstools” package in Ubuntu:
  Fix Released
Status in “dosfstools” source package in Lucid:
  New
Status in “dosfstools” source package in Maverick:
  Won't Fix
Status in “dosfstools” source package in Natty:
  New
Status in “dosfstools” source package in Hardy:
  New

Bug description:
  Binary package hint: dosfstools

  mkdosfs  will incorrectly calculate the number of sectors of a given
  FAT partition if the number sectors are odd due to count_blocks
  incorrectly handling the remainder of a division operation. This
  miscalculation causes the OMAP4 bootloader to fail to boot.

  This bug can be observed by comparing the total sector size in fdisk
  expert more to fsck.msdos; this discrepancy only shows up when the
  number of sectors are odd:

  fdisk output:

  Expert command (m for help): p

  Disk /dev/sdb: 204 heads, 3 sectors, 12654 cylinders

  Nr AF  Hd Sec  Cyl  Hd Sec  Cyl     Start      Size ID
   1 00   1   1    0 203   3  258          3     158505 83
   2 00   0   0    0   0   0    0          0          0 00
   3 00   0   0    0   0   0    0          0          0 00
   4 00   0   0    0   0   0    0          0          0 00

  
  mcasadevall at daybreak:~/src/dosfstools-3.0.9$ sudo fsck.msdos -v /dev/sdb1
  dosfsck 3.0.9 (31 Jan 2010)
  dosfsck 3.0.9, 31 Jan 2010, FAT32, LFN
  Checking we can access the last sector of the filesystem
  Boot sector contents:
  System ID "mkdosfs"
  Media byte 0xf8 (hard disk)
         512 bytes per logical sector
        2048 bytes per cluster
           4 reserved sectors
  First FAT starts at byte 2048 (sector 4)
           2 FATs, 16 bit entries
       79872 bytes per FAT (= 156 sectors)
  Root directory starts at byte 161792 (sector 316)
         512 root directory entries
  Data area starts at byte 178176 (sector 348)
       39539 data clusters (80975872 bytes)
  3 sectors/track, 204 heads
           0 hidden sectors
      158504 sectors total
  Checking for unused clusters.
  /dev/sdb1: 0 files, 0/39539 clusters

  Compare the difference in sectors total. The attached patch correctly
  handles the remainder and causes the sector counts to match.

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