Hello Abhijith, On Tue, Mar 27, 2012 at 5:22 AM, Abhijith Das <adas@xxxxxxxxxx> wrote: > Hi, > > Here's a patch to the fcntl.2 manpage that explains > the working of F_GETLEASE in a bit more detail during > lease breaks. Basically, what happens is this: When a > lease break is initiated by a lease breaker, subsequent > F_GETLEASE calls return the target lease type after > the lease break and not the existing lease type. This > behavior persists until the lease holder downgrades/unlocks > the lease or the kernel forcibly does it after the lease > break timeout expires. > > The implicit assumption is that F_GETLEASE should > return the existing lock type until the downgrade/unlock > has actually taken place, which is not true. I've verified > that the kernel indeed returns the target lease type. It > is also simple enough to verify this behavior in a small > program, where you can observe that the lease type > returned by F_GETLEASE in the signal handler for a > lease break is different from the existing lease type. Thanks. Looks good to me. Applied for man-pages-3.39. Cheers, Michael > Signed-off-by: Abhi Das <adas@xxxxxxxxxx> > > diff --git a/man2/fcntl.2 b/man2/fcntl.2 > index b2a985a..5256dc6 100644 > --- a/man2/fcntl.2 > +++ b/man2/fcntl.2 > @@ -865,6 +865,16 @@ the number of seconds specified in > .I /proc/sys/fs/lease-break-time > then the kernel forcibly removes or downgrades the lease holder's lease. > > +Once a lease break has been initiated, > +.B F_GETLEASE > +returns the target lease type (either > +.B F_RDLCK > +or > +.B F_UNLCK > +depending on what would be compatible with the lease breaker) until the > +lease holder voluntarily downgrades or removes the lease or the kernel > +forcibly does so after the lease break timer expires. > + > Once the lease has been voluntarily or forcibly removed or downgraded, > and assuming the lease breaker has not unblocked its system call, > the kernel permits the lease breaker's system call to proceed. -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface"; http://man7.org/tlpi/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
