Bug 12953

Summary:	wrong limit on sysctl fs.lease-break-time
Product:	IO/Storage	Reporter:	Arne de Bruijn (kernelbt)
Component:	File Locking	Assignee:	Matthew Wilcox (matthew)
Status:	RESOLVED CODE_FIX
Severity:	normal
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:		Subsystem:
Regression:	Yes	Bisected commit-id:
Attachments:	patch

Description Arne de Bruijn 2009-03-27 12:58:32 UTC

In kernel 2.6.15 I was able to reduce lease-break-time to 5 seconds. In kernel 2.6.28 this fails with invalid argument:
# sysctl -w fs.lease-break-time=5
error: "Invalid argument" setting key "fs.lease-break-time"

kernel/sysctl.c shows lease-break-time is limited to a value from 0 to 2, and setting it to 2 does indeed work. This seems wrong, the default is 45.

I traced this to the following commit:
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=76fdbb25f963de5dc1e308325f0578a2f92b1c2d
(coredump masking: bound suid_dumpable sysctl)
which seems put a limit on the wrong sysctl.

Comment 1 Matthew Wilcox 2009-03-27 13:24:06 UTC

Created attachment 20701 [details]
patch

Comment 2 Matthew Wilcox 2009-03-27 13:25:41 UTC

Thanks for tracking down the exact commit that introduced the problem.  It made the above patch very easy to write.  I'll send it to the stable tree as well as Linus.