git: kernel - check nc_generation in nlookup path
dillon at crater.dragonflybsd.org
Sun Jul 3 22:28:40 PDT 2022
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Sun Jul 3 20:47:32 2022 -0700
kernel - check nc_generation in nlookup path
* With nc_generation now operating in a more usable manner, we can
use it in nlookup() to check for changes. When a change is detected,
the related lock will be cycled and the entire nlookup() will retry up
to debug.nlookup_max_retries, which currently defaults to 4.
* Add debugging via debug.nlookup_debug. Set to 3 for nc_generation
* Move "Parent directory lost" kprintfs into a debugging conditional,
reported via (debug.nlookup_debug & 4).
* This fixes lookup/remove races which could sometimes cause open()
and other system calls to return EINVAL or ENOTCONN. Basically
what happened was that nlookup() wound up on a NCF_DESTROYED entry.
* A few minutes worth of a dsynth bulk does not report any random
generation number mismatches or retries, so the code in this commit
is probably very close to correct.
Summary of changes:
sys/kern/vfs_cache.c | 39 ++++++---
sys/kern/vfs_nlookup.c | 229 +++++++++++++++++++++++++++++++++++-------------
sys/kern/vfs_syscalls.c | 10 ++-
sys/kern/vfs_vnops.c | 3 +
sys/sys/namecache.h | 2 +-
5 files changed, 210 insertions(+), 73 deletions(-)
DragonFly BSD source repository
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