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For a few days i'm breaking my head over the following:

  • the partition table is reported to be messed up, but it's not.
  • grub-legacy gives problems with some partitions during actual boot-up, but not when invoked in a shell when linux is up-and-running.

I suspect the two symptoms are related, but i'm not sure.

Background information:

  • Grub-legacy has been booting from an XFS on /dev/sda4 a.k.a. (hd0,3) for years without trouble.
  • Things got messed up when resizing the FAT32 filesystem on sda1 using Gparted (apparently there is a bug in libparted 3.2 responsible for this). Suddenly grub couldn't access sda4 anymore.

Here is the output from fdisk concerning th broken-not-broken partition table:

Welcome to fdisk (util-linux 2.27.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help): p Disk /dev/sda: 74.5 GiB, 80026361856 bytes, 156301488 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x85068506 Device Boot Start End Sectors Size Id Type /dev/sda1 2048 8390655 8388608 4G c W95 FAT32 (LBA) /dev/sda2 * 8390656 29296639 20905984 10G 7 HPFS/NTFS/exFAT /dev/sda3 29296640 136712191 107415552 51.2G f W95 Ext'd (LBA) /dev/sda4 136712192 156301487 19589296 9.3G 83 Linux /dev/sda5 29298688 33492991 4194304 2G 83 Linux /dev/sda6 33495040 75438079 41943040 20G 83 Linux /dev/sda7 75440128 83828735 8388608 4G 83 Linux /dev/sda8 83830784 88025087 4194304 2G 83 Linux /dev/sda9 88027136 94318591 6291456 3G 82 Linux swap Partition table entries are not in disk order. Command (m for help): x Expert command (m for help): f Nothing to do. Ordering is correct already.

parted lists the partition table as follows:

# parted /dev/sda unit s print free Model: ATA WDC WD800JB-00JJ (scsi) Disk /dev/sda: 156301488s Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags 63s 2047s 1985s Free Space 1 2048s 8390655s 8388608s primary fat32 boot, lba 2 8390656s 29296639s 20905984s primary ntfs 3 29296640s 136712191s 107415552s extended lba 5 29298688s 33492991s 4194304s logical ext2 6 33495040s 75438079s 41943040s logical ext3 7 75440128s 83828735s 8388608s logical ext3 8 83830784s 88025087s 4194304s logical ext3 9 88027136s 94318591s 6291456s logical linux-swap(v1) 94318592s 136712191s 42393600s Free Space 4 136712192s 156301487s 19589296s primary ext2

About grub during boot-up:

  • it reports "Error 5: partition table invalid or corrupt" for sda7 and sda8.
  • it reports "Filesystem type unknown" for sda4, though it's a simple ext2 (by now).

I've searched many many forums/wikis/etc, but haven't solved this puzzle yet. I've only come to realise my partition table is 1MiB-aligned (hence the 2048 sector gaps). I've done some partition deletion/recreation/reformatting/checking etc, without success.

I'm running slackware 14.2 (salix, actually) with kernel 3.10. All linux filesystems are ext2 or ext3.

I'm very curious to find the cause of these symptoms. Please help me to tackle this.

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The reason it says Partition table entries are not in disk order. is because they aren't. Your sda4 is at the end of the disk, but sda5-9 is located before that.

In parted the output should look something like this:

# parted /dev/loop0 unit s print free Model: Loopback device (loopback) Disk /dev/loop0: 156301488s Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags 63s 2047s 1985s Free Space 1 2048s 8390655s 8388608s primary lba 2 8390656s 29296639s 20905984s primary boot 3 29296640s 136712191s 107415552s extended lba 5 29298688s 33492991s 4194304s logical 6 33495040s 75438079s 41943040s logical 7 75440128s 83828735s 8388608s logical 8 83830784s 88025087s 4194304s logical 9 88027136s 94318591s 6291456s logical 94318592s 136712191s 42393600s Free Space 4 136712192s 156301487s 19589296s primary

Note that's just the explanation about the fdisk message. If you convert the last primary partition to a logical one, the message goes away. I'm not sure if that is related in any way whatsoever to your other partition problems.

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    In parted the output actually does look exactly like your example. I've added the output to the question. Apparently parted and fdisk just differ in the way how they present logical partitions: fdisk orders them by number, and therefore always after the primary partitions, and parted orders them by order on disk. Commented May 10, 2017 at 20:09
  • AFAIK fdisk makes more sense in this, since information about logical partitions is not stored in the MBR but further down the disk, in the extended partition itself. Commented May 10, 2017 at 20:11

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