cryfs vault unresponsive for a long time after mount on KDE

[ZviBaratz]

Hi all,

I'm copying my bug report from KDE's board, which was determined to originate from cryfs. Unfortunately, I'm not sure what cryfs version I was using, but it should be whatever was the latest 2019-12-08.

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SUMMARY
After mounting the vault I get the following notification:
"Filesystem is not responding: filesystem mounted at '' is not responding."
Trying to access it through dolphin causes dolphin to become completely stuck (terminating doesn't work, not even with kill -9). This could be a similar problem to the unresolved bug #409494.
After a long time the directory becomes accessible but very slow. On one occasion it even caused a complete system freeze that required a hard reboot (very long time with no response, even REISUB failed).
Trying to unmount the vault during the long period of time (circa 20-30 minutes) that it is unresponsive gives an error in the vaults applet ("device is being used by another application" or something of the sort) and the mount/unmount icon toggles at a very high frequency until it is resolved.

STEPS TO REPRODUCE

1. Create a vault with the base directory and mount point located in a custom location outside the OS's HD.
2. Copy a large number of files weighing a couple of hundreds of GBs into the vault.
3. Mount vault and try to access.

OBSERVED RESULT
Dolphin freezes, vault is inaccessible, it is impossible to unmount vault.

EXPECTED RESULT
Vault is promptly mounted and contained data is accessible. Unmounting is possible on command.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 19.10
(available in About System)
KDE Plasma Version: 5.16.5
KDE Frameworks Version: 5.62.0
Qt Version: 5.12.4

ADDITIONAL INFORMATION
cryfs encoding scheme. Large number of files (altogether ~400GB, if that could be relevant). Also, the base directory as well as the mount point are not on the main SSD hard-drive on which the OS is installed, but on a separate HDD.
Using cryfs to access the directory in the terminal works fine.

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Thank you very much for all your awesome work!

[mhogomchungu]

CryFS encrypts user data and store them in 32KB files by default.

400GB worth of data will produce a whole lot of these 32KB files and any tool that will attempt to process them will take a very, very, very long time to complete.

With that amount of data, the solution is for nobody to even attempt to look at the base directory unless they are equipt to see a whole lot of very small files.

[smessmer]

If most files in your file system are much larger than 32kb, you could try to create a CryFS file system with larger block sizes. That reduces the number of blocks created and should give you a better experience.

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On May 28, 2020 12:35:34 AM mhogomchungu ***@***.***> wrote: CryFS encrypts user data and store them in 32KB files by default. 400GB worth of data will produce a whole lot of these 32KB files and any tool that will attempt to process them will take a very, very, very long time to complete. With that amount of data, the solution is for nobody to even attempt to look at the base directory unless they are equipt to see a whole lot of very small files. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.