android_kernel_samsung_msm8976/include
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
..
acpi ACPICA: disable _BIF warning 2008-11-27 02:17:30 -05:00
asm-arm
asm-frv
asm-generic atomic: fix a typo in atomic_long_xchg() 2008-12-10 08:01:53 -08:00
asm-h8300
asm-m32r
asm-m68k proc: move /proc/hardware to m68k-specific code 2008-10-23 14:24:03 +04:00
asm-mn10300 MN10300: Fix __put_user_asm8() 2008-12-10 13:34:33 -08:00
asm-xtensa Merge git://git.kernel.org/pub/scm/linux/kernel/git/czankel/xtensa-2.6 2008-10-23 09:16:56 -07:00
crypto
drm drm: move drm vblank initialization/cleanup to driver load/unload 2008-11-25 09:49:03 +10:00
keys
linux optimize attribute timeouts for "noac" and "actimeo=0" 2008-12-23 15:21:56 -05:00
math-emu math-emu: Fix thinko in _FP_DIV 2008-10-22 22:09:59 -07:00
media
mtd
net irda: Add irda_skb_cb qdisc related padding 2008-12-17 15:44:58 -08:00
pcmcia
rdma
rxrpc
scsi [SCSI] fc_transport: fix old bug on bitflag definitions 2008-11-21 17:30:53 +09:00
sound Merge branches 'topic/fix/misc' and 'topic/fix/hda' into for-linus 2008-11-10 17:58:46 +01:00
trace
video Revert "radeonfb: accelerate imageblit and other improvements" 2008-12-10 16:53:32 -08:00
xen
Kbuild