[LU-15220] Linux kernel 5.14 support

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.15.0
• Assignee: Jian Yu
• Reporter: Jian Yu

Description

Main changes needed to support Linux kernel 5.14 include:

• __set_page_dirty() is no longer exported
• idmapped mounts support, which adds 'struct user_namespace *' to all VFS operations (since kernel 5.12)
• '/* fallthrough */' hits implicit-fallthrough error with gcc version 11. Using the pseudo keyword 'fallthrough' to resolve the issue
• needs to import namespace CRYPTO_INTERNAL (since kernel 5.12)

Issue Links

• is related to: LU-16013 SLES15 SP4 client BUG: kernel NULL pointer dereference
• is related to: LU-15420 Linux kernel 5.15 support
• is related to: LU-12511 Prepare lustre for adoption into the linux kernel
• is related to: LU-14651 Linux kernel 5.12 support

Comments

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/45812/
Subject: LU-15220 libcfs: fix panic_notifier_list undeclared error
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: fb545fa83837c1478ad41f752cf5d3e313b67c73

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/45927/
Subject: LU-15220 llite: Compat for set_pagevec_dirty
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 8fdef1381ea07657d6689818b2897d69cb7e9c83

[Jian Yu]

Hi Ihara,
Please apply all of the un-merged patches in this ticket and those in LU-14651.

[Shuichi Ihara]

yujian does head of https://review.whamcloud.com/#/c/45566/ contain all considerations of linux-5.14?
I'm trying to build patch 45566 against 5.14.0-1018-oem (Ubuntu20.04), but still getting bunch of errors.

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/45814/
Subject: LU-15220 utils: fix gcc-11 -Werror=mismatched-dealloc error
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 64ba2b18349b56c5d7ade944ea713bade84bc02e

[Jian Yu]

Sure, Patrick. Thank you.

[Patrick Farrell]

Jian,

Can you take that patch and test it on the newer kernels?  I don't have the right environments available.  Thanks!

[Gerrit Updater]

"Patrick Farrell <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/45927
Subject: LU-15220 llite: Compat for set_pagevec_dirty
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 3757b2168e7670d513270427634324695e5ec6d4

[Patrick Farrell]

Jian,

Oof, this is actually pretty complicated.

I see Neil changed the code here with https://review.whamcloud.com/#/c/40827/ .  That basically makes this function pointless in these kernels - the entire point is to avoid taking the xarray lock for each page...  Hmm.

OK, here is my suggested solution for compatibility, since we have already lost the desired xarray lock behavior.  I will look at restoring that, but in the meantime:

For kernels which do not have account_page_dirtied, which should also include kernels which do not have __set_page_dirty, the right thing to do is replace all of the code in vvp_set_pagevec_dirty with a loop calling __set_page_dirty_nobuffers on the pages in the pagevec.

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/45815/
Subject: LU-15220 utils: fix gcc-11 -Werror=format-truncation= error
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 9b0b7264a8d7a6a2abe681d15fefc88c27d20c1e

[Jian Yu]

Hi Patrick,
In kernel 5.14.0, __set_page_dirty() is no longer exported, which affects ll_account_page_dirtied()/vvp_account_page_dirtied() in lustre/llite/vvp_dev.c.
Copying the codes from __set_page_dirty() doesn't work because the account_page_dirtied() in it is also not exported.
Could you please advise how to resolve this issue? Can we use _set_page_dirty_nobuffers() instead of _set_page_dirty()?