| 2016-10-03 21:37:30 |
Ryan Harper |
description |
During format handling, curtin detects the underlying block size of the disk and sets the filesystem block size accordingly.
In order to properly handle a bug in mkfs.vfat, curtin adds the flag '-s 1'. However, curtin adds this flag to all disk format commands, not just to commands using 'mkfs.vfat'. This can lead to unexpected behavior with some formatting tools, and can cause installation to halt with others.
For example, the mkfs.btrfs utility understands '-s' to mean sectorsize, so when curtin installs to an advanced format disk and storage config includes a btrfs formatted filesystem, curtin will create a filesystem that uses 1 byte sectors. This will greatly harm filesystem performance.
For xfs volumes, this means that installation will fail completely, as the sectorsize attribute for xfs volumes must be specified in the format '-s size=512', so '-s 1' will cause mkfs.xfs to fail.
Fortunately, this does not affect mkfs.ext* because these tools seem to silently ignore the '-s' flag, so most users likely have not been affected. |
[Impact]
* curtin passes wrong args to mkfs when making filesystem on advanced
format disks (4k sector size)
Curtin has been modified to only pass the '-s 1' sector-size flag
to the vfat formatting tools. Curtin has been updated to specify
the correct sector-size flags and values to other formatting
utilities that support such settings.
[Test Case]
* Install proposed curtin package and attempt to format a disk with
xfs filesystem using 4K logical blocksize for the disk.
PASS: Ubuntu successfully installs with xfs filesystem on top of a
4k Disk
FAIL: Ubuntu fails to install with xfs filesystem on 4k disk.
[Regression Potential]
* Low; current users expecting xfs on 4k disks were blocked without
this fix.
[Original Description]
During format handling, curtin detects the underlying block size of the disk and sets the filesystem block size accordingly.
In order to properly handle a bug in mkfs.vfat, curtin adds the flag '-s 1'. However, curtin adds this flag to all disk format commands, not just to commands using 'mkfs.vfat'. This can lead to unexpected behavior with some formatting tools, and can cause installation to halt with others.
For example, the mkfs.btrfs utility understands '-s' to mean sectorsize, so when curtin installs to an advanced format disk and storage config includes a btrfs formatted filesystem, curtin will create a filesystem that uses 1 byte sectors. This will greatly harm filesystem performance.
For xfs volumes, this means that installation will fail completely, as the sectorsize attribute for xfs volumes must be specified in the format '-s size=512', so '-s 1' will cause mkfs.xfs to fail.
Fortunately, this does not affect mkfs.ext* because these tools seem to silently ignore the '-s' flag, so most users likely have not been affected. |
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