1
0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-24 11:29:10 +00:00
freebsd/sys/ufs
Kirk McKusick 86aeb27fa2 Change locking so that all snapshots on a particular filesystem share
a common lock. This change avoids a deadlock between snapshots when
separate requests cause them to deadlock checking each other for a
need to copy blocks that are close enough together that they fall
into the same indirect block. Although I had anticipated a slowdown
from contention for the single lock, my filesystem benchmarks show
no measurable change in throughput on a uniprocessor system with
three active snapshots. I conjecture that this result is because
every copy-on-write fault must check all the active snapshots, so
the process was inherently serial already. This change removes the
last of the deadlocks of which I am aware in snapshots.

Sponsored by:	DARPA & NAI Labs.
2002-10-16 00:19:23 +00:00
..
ffs Change locking so that all snapshots on a particular filesystem share 2002-10-16 00:19:23 +00:00
ufs Push most UFS ACL behavior behind a check for MNT_ACLS, permitting ACLs 2002-10-15 21:28:24 +00:00