In 5c05a339c6 I retroactively changed the NEWS
entry for v259. But this is very confusing, because it looks like the original
change never happened and it's not clear what is being reverted.
Let's restore the original text, and just add a short note, but then move
the new text to the section for v260.
XDG_SESSION_EXTRA_DEVICE_ACCESS will now take a colon-separated list of
identifiers. For every identifier $ID, the session is granted access to all
devices tagged as "xaccess-$ID" in udev.
Fixes: #40634
Mostly consists of fixes to
- use the same sector_size as the fdisk context we are using, when
converting between sectors returned by libfdisk to bytes. Fixes#30394 ,
Fixes#30393
- Use the explicit sector size if specified in the home record when are
probing the image file using libblkid. Fixes#30393
Also contains some other improvements with using physical block devices.
- Automatically probe sector size of physical block device, if user does
not pass luks-sector-size explicitly.
- Assign partitions to 1 MiB boundaries, as it is the standard practice
followed by all tools, fdisk, gptfdisk, gnu parted etc.
- Avoid stacking of loop device on top of physical block device in
home_create_luks as it leads to degradation of discard operations, and
mkfs getting stuck.
This is a general cleanup of the sensors hwdb file divides into several
commits per brand.
I have merged the devices that use the same matrices, clean up a little
some clear dmi matches, and apply a inline comment with the device where
is certainly very clear way to display.
My idea is to do more cleanup steps but actually will require more
effort to achieve complete dmis, I can do it with little time, and some
consensus for comment styling.
About the comment styling actually I thing we could follow two rules at
the same time: inline comment when the dmi match is short and there is
no additional many information than just the model, and the other one
comment above the dmi match when is too long or there are need to add
more info.
Fix for specific case #30393 where 4k sector luks container is created
on a 512b device. In this case the partition table needs to be 512b,
else the kernel will not be able to find the partition, and we will
have to create a loop device to translate the partition table to 4k.
Ensure we don't create a loop device on top of a physical block device.
This leads to huge performance degradation of discard operations if the
physical device does not support discard_on_zeroes.
- loop device historical semantics dictates that when the device is
discarded, it needs to return zero data on read. This can be
implemented easily on a filesystem. since fallocate zero-range
would return immediately & the holes are handled at the filesystem
level to return zero data on read.
- For a raw block device, the feature (discard_zeroes_data) depends on
the capabilities of the physical device that is exposed to the
block layer by the driver. This means that to guarantee that the loop
device stacked on a block device returns zero on discarded data,
it needs to convert discarded range into write_zero op on the block device.
https://github.com/torvalds/linux/blob/63676eefb7a026d04b51dcb7aaf54f358517a2ec/drivers/block/loop.c#L773
For example on one of my local nvme I can see the following:
cat /sys/class/block/nvme1n1/queue/write_zeroes_max_bytes
131072
cat /sys/class/block/nvme0n1/queue/discard_max_hw_bytes
2199023255040
This means maximum size of a write_zero operation can be 128KiB &
maximum size of discard operation can be 2TiB on the block device.
So discarding for example 1TB of data, which would be a single block
device operation, gets split into 8.3 million block device operations
when issued on top of stacked loop device.
If there is an explicit sector size specified in the user record,
use the same when probing the file using libblkid. The default
is 512 bytes, which will not be able to find the signatures, if the
partition table on regular file was created assuming 4k sectors
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Luca Boccassi
Mike Yuan
Jörg Behrmann
Alessandro Astone
AsciiWolf
scarlet-storm
David Santamaría Rogado