[lkml]   [2006]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex

    > On Fri, Nov 10, 2006 at 12:11:46AM +0100, Pavel Machek wrote:
    > > ? Not sure if I quite understand, but if dm breaks sync... something
    > > is teribly wrong with dm. And we do simple sys_sync()... so I do not
    > > think we have a problem.
    > If you want to handle arbitrary kernel state, you might have a device-mapper
    > device somewhere lower down the stack of devices that is queueing any I/O
    > that reaches it. So anything waiting for I/O completion will wait until
    > the dm process that suspended that device has finished whatever it is doing
    > - and that might be a quick thing carried out by a userspace lvm tool, or
    > a long thing carried out by an administrator using dmsetup.
    > I'm guessing you need a way of detecting such state lower down the stack
    > then optionally either aborting the operation telling the user it can't be
    > done at present; waiting for however long it takes (perhaps for ever if
    > the admin disappeared); or more probably skipping those devices on a
    > 'best endeavours' basis.

    Okay, so you claim that sys_sync can stall, waiting for administator?

    In such case we can simply do one sys_sync() before we start freezing
    userspace... or just more the only sys_sync() there. That way, admin
    has chance to unlock his system.

    (cesky, pictures)
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2006-11-10 00:37    [W:0.021 / U:13.348 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site