mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/
synced 2026-04-18 06:33:43 -04:00
1f6ee9be92
Commit7d6899fb69("ovl: fsync after metadata copy-up") was done to fix durability of overlayfs copy up on an upper filesystem which does not enforce ordering on storing of metadata changes (e.g. ubifs). In an earlier revision of the regressing commit by Lei Lv, the metadata fsync behavior was opt-in via a new "fsync=strict" mount option. We were hoping that the opt-in mount option could be avoided, so the change was only made to depend on metacopy=off, in the hope of not hurting performance of metadata heavy workloads, which are more likely to be using metacopy=on. This hope was proven wrong by a performance regression report from Google COS workload after upgrade to kernel 6.12. This is an adaptation of Lei's original "fsync=strict" mount option to the existing upstream code. The new mount option is mutually exclusive with the "volatile" mount option, so the latter is now an alias to the "fsync=volatile" mount option. Reported-by: Chenglong Tang <chenglongtang@google.com> Closes: https://lore.kernel.org/linux-unionfs/CAOdxtTadAFH01Vui1FvWfcmQ8jH1O45owTzUcpYbNvBxnLeM7Q@mail.gmail.com/ Link: https://lore.kernel.org/linux-unionfs/CAOQ4uxgKC1SgjMWre=fUb00v8rxtd6sQi-S+dxR8oDzAuiGu8g@mail.gmail.com/ Fixes:7d6899fb69("ovl: fsync after metadata copy-up") Depends:50e638beb6("ovl: Use str_on_off() helper in ovl_show_options()") Cc: stable@vger.kernel.org # v6.12+ Signed-off-by: Fei Lv <feilv@asrmicro.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com>