Lmst

#Blockdevicedriver

Block Devices in User Space https://hackaday.com/2026/01/20/block-devices-in-user-space/
#LinuxHacks #SoftwareDevelopment #SoftwareHacks #Blockdevicedriver #Linux #Ublk

Block Devices in User Space

https://web.brid.gy/r/https://hackaday.com/2026/01/20/block-devices-in-user-space/

<div><img alt="" class="attachment-large size-large wp-post-image" height="466" src="https://hackaday.com/wp-content/uploads/2026/01/ublk.png?w=800" style="margin: 0 auto; margin-bottom: 15px;" width="800" /></div><p>Your new project really could use a block device for Linux. File systems are easy to do with FUSE, but that’s sometimes too high-level. But a block driver can be tough to write and debug, especially since bugs in the kernel’s space can be catastrophic. [Jiri Pospisil] <a href="https://jpospisil.com/posts/2026-01-13-creating-virtual-block-devices-with-ublk" target="_blank">suggests</a> <a href="https://www.kernel.org/doc/html/latest/block/ublk.html" target="_blank">Ublk</a>, a framework for writing block devices in user space. This works using the <a href="https://en.wikipedia.org/wiki/Io_uring" target="_blank">io_uring</a> facility in recent kernels.</p>
<p>This opens the block device field up. You can use any language you want (we’ve seen FUSE used with some very strange languages). You can use libraries that would not work in the kernel. Debugging is simple, and crashing is a minor inconvenience.</p>
<p>Another advantage? Your driver won’t depend on the kernel code. There is a kernel driver, of course, named ublk_drv, but that’s not your code. That’s what your code talks to.</p>
<p><span id="more-906004"></span></p>
<p>The driver maintains the block devices and relays I/O and ioctl requests to your code for servicing. There a

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