kernel_optimize_test/net
Peter Staubach 64672d55d9 optimize attribute timeouts for "noac" and "actimeo=0"
Hi.

I've been looking at a bugzilla which describes a problem where
a customer was advised to use either the "noac" or "actimeo=0"
mount options to solve a consistency problem that they were
seeing in the file attributes.  It turned out that this solution
did not work reliably for them because sometimes, the local
attribute cache was believed to be valid and not timed out.
(With an attribute cache timeout of 0, the cache should always
appear to be timed out.)

In looking at this situation, it appears to me that the problem
is that the attribute cache timeout code has an off-by-one
error in it.  It is assuming that the cache is valid in the
region, [read_cache_jiffies, read_cache_jiffies + attrtimeo].  The
cache should be considered valid only in the region,
[read_cache_jiffies, read_cache_jiffies + attrtimeo).  With this
change, the options, "noac" and "actimeo=0", work as originally
expected.

This problem was previously addressed by special casing the
attrtimeo == 0 case.  However, since the problem is only an off-
by-one error, the cleaner solution is address the off-by-one
error and thus, not require the special case.

    Thanx...

        ps

Signed-off-by: Peter Staubach <staubach@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23 15:21:56 -05:00
..
9p 9p: restrict RDMA usage 2008-11-12 23:33:57 -08:00
802 net/802/fc.c: Fix compilation warnings 2008-10-15 00:13:53 -07:00
8021q vlan: Fix typos in proc output string 2008-11-10 13:37:40 -08:00
appletalk net: Rationalise email address: Network Specific Parts 2008-10-13 19:01:08 -07:00
atm ATM: CVE-2008-5079: duplicate listen() on socket corrupts the vcc table 2008-12-04 14:58:13 -08:00
ax25 ax25: Quick fix for making sure unaccepted sockets get destroyed. 2008-10-06 12:53:50 -07:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2008-10-17 08:58:52 -07:00
bridge bridge: netfilter: fix update_pmtu crash with GRE 2008-11-24 16:06:50 -08:00
can can: omit received RTR frames for single ID filter lists 2008-12-04 15:01:08 -08:00
core netpoll: fix race on poll_list resulting in garbage entry 2008-12-09 23:22:26 -08:00
dccp dccp: Port redirection support for DCCP 2008-10-19 23:36:47 -07:00
decnet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2008-10-17 08:58:52 -07:00
dsa dsa: fix master interface allmulti/promisc handling 2008-11-10 21:53:12 -08:00
econet
ethernet dsa: add support for Trailer tagging format 2008-10-08 17:24:16 -07:00
ieee80211 net/ieee80211: adjust error handling 2008-08-22 16:29:49 -04:00
ipv4 netfilter: update rwlock initialization for nat_table 2008-12-15 00:19:14 -08:00
ipv6 ipv6: silence log messages for locally generated multicast 2008-12-09 15:48:32 -08:00
ipx
irda
iucv iucv: Fix mismerge again. 2008-09-30 03:03:35 -07:00
key af_key: mark policy as dead before destroying 2008-11-06 23:08:37 -08:00
lapb
llc
mac80211 mac80211: use unaligned safe memcmp() in-place of compare_ether_addr() 2008-12-05 09:18:35 -05:00
netfilter tproxy: fixe a possible read from an invalid location in the socket match 2008-12-07 23:53:46 -08:00
netlabel netlabel: Compiler warning and NULL pointer dereference fix 2008-12-11 21:31:50 -08:00
netlink net: Remove CONFIG_KMOD from net/ (towards removing CONFIG_KMOD entirely) 2008-10-16 15:24:51 -07:00
netrom netrom: Fix sock_orphan() use in nr_release 2008-10-06 12:54:57 -07:00
packet
phonet Phonet: keep TX queue disabled when the device is off 2008-12-15 00:53:57 -08:00
rfkill Fix logic error in rfkill_check_duplicity 2008-11-06 16:37:09 -05:00
rose rose: zero length frame filtering in af_rose.c 2008-11-25 00:56:20 -08:00
rxrpc
sched SCHED: netem: Correct documentation comment in code. 2008-12-15 00:39:17 -08:00
sctp sctp: Fix to handle SHUTDOWN in SHUTDOWN_RECEIVED state 2008-10-23 01:01:18 -07:00
sunrpc optimize attribute timeouts for "noac" and "actimeo=0" 2008-12-23 15:21:56 -05:00
tipc tipc: Don't use structure names which easily globally conflict. 2008-09-02 23:38:32 -07:00
unix net: Fix soft lockups/OOM issues w/ unix garbage collector 2008-11-26 15:32:27 -08:00
wanrouter
wireless net/wireless/reg.c: fix bad WARN_ON in if statement 2008-11-25 16:13:09 -05:00
x25
xfrm xfrm: Fix kernel panic when flush and dump SPD entries 2008-12-03 00:27:18 -08:00
compat.c reintroduce accept4 2008-11-19 18:49:57 -08:00
Kconfig net: Distributed Switch Architecture protocol support 2008-10-08 17:15:19 -07:00
Makefile net: Distributed Switch Architecture protocol support 2008-10-08 17:15:19 -07:00
nonet.c
socket.c reintroduce accept4 2008-11-19 18:49:57 -08:00
sysctl_net.c
TUNABLE