Eric Lee / smarc-fsl-linux-kernel

18 May, 2016

1 commit

  • 183d9e7b1   pnfs: rework LAYOUTGET retry handling ... Browse Code »

    There are several problems in the way a stateid is selected for a
    LAYOUTGET operation:

    We pick a stateid to use in the RPC prepare op, but that makes
    it difficult to serialize LAYOUTGETs that use the open stateid. That
    serialization is done in pnfs_update_layout, which occurs well before
    the rpc_prepare operation.

    Between those two events, the i_lock is dropped and reacquired.
    pnfs_update_layout can find that the list has lsegs in it and not do any
    serialization, but then later pnfs_choose_layoutget_stateid ends up
    choosing the open stateid.

    This patch changes the client to select the stateid to use in the
    LAYOUTGET earlier, when we're searching for a usable layout segment.
    This way we can do it all while holding the i_lock the first time, and
    ensure that we serialize any LAYOUTGET call that uses a non-layout
    stateid.

    This also means a rework of how LAYOUTGET replies are handled, as we
    must now get the latest stateid if we want to retransmit in response
    to a retryable error.

    Most of those errors boil down to the fact that the layout state has
    changed in some fashion. Thus, what we really want to do is to re-search
    for a layout when it fails with a retryable error, so that we can avoid
    reissuing the RPC at all if possible.

    While the LAYOUTGET RPC is async, the initiating thread always waits for
    it to complete, so it's effectively synchronous anyway. Currently, when
    we need to retry a LAYOUTGET because of an error, we drive that retry
    via the rpc state machine.

    This means that once the call has been submitted, it runs until it
    completes. So, we must move the error handling for this RPC out of the
    rpc_call_done operation and into the caller.

    In order to handle errors like NFS4ERR_DELAY properly, we must also
    pass a pointer to the sliding timeout, which is now moved to the stack
    in pnfs_update_layout.

    The complicating errors are -NFS4ERR_RECALLCONFLICT and
    -NFS4ERR_LAYOUTTRYLATER, as those involve a timeout after which we give
    up and return NULL back to the caller. So, there is some special
    handling for those errors to ensure that the layers driving the retries
    can handle that appropriately.

    Signed-off-by: Jeff Layton
    Signed-off-by: Anna Schumaker

    Jeff Layton
     

08 May, 2013

1 commit

  • 41003a7bc   aio: remove retry-based AIO ... Browse Code »

    This removes the retry-based AIO infrastructure now that nothing in tree
    is using it.

    We want to remove retry-based AIO because it is fundemantally unsafe.
    It retries IO submission from a kernel thread that has only assumed the
    mm of the submitting task. All other task_struct references in the IO
    submission path will see the kernel thread, not the submitting task.
    This design flaw means that nothing of any meaningful complexity can use
    retry-based AIO.

    This removes all the code and data associated with the retry machinery.
    The most significant benefit of this is the removal of the locking
    around the unused run list in the submission path.

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Kent Overstreet
    Signed-off-by: Zach Brown
    Cc: Zach Brown
    Cc: Felipe Balbi
    Cc: Greg Kroah-Hartman
    Cc: Mark Fasheh
    Cc: Joel Becker
    Cc: Rusty Russell
    Cc: Jens Axboe
    Cc: Asai Thambi S P
    Cc: Selvan Mani
    Cc: Sam Bradshaw
    Acked-by: Jeff Moyer
    Cc: Al Viro
    Cc: Benjamin LaHaise
    Reviewed-by: "Theodore Ts'o"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Zach Brown
     

13 Oct, 2012

1 commit

02 Jun, 2012

1 commit

  • 16b1c1cd7   vfs: retry last component if opening stale dentry ... Browse Code »

    NFS optimizes away d_revalidates for last component of open. This means that
    open itself can find the dentry stale.

    This patch allows the filesystem to return EOPENSTALE and the VFS will retry the
    lookup on just the last component if possible.

    If the lookup was done using RCU mode, including the last component, then this
    is not possible since the parent dentry is lost. In this case fall back to
    non-RCU lookup. Currently this is not used since NFS will always leave RCU
    mode.

    Signed-off-by: Miklos Szeredi
    Signed-off-by: Al Viro

    Miklos Szeredi
     

09 Mar, 2012

1 commit

  • d1c3414c2   drivercore: Add driver probe deferral mechanism ... Browse Code »

    Allow drivers to report at probe time that they cannot get all the resources
    required by the device, and should be retried at a later time.

    This should completely solve the problem of getting devices
    initialized in the right order. Right now this is mostly handled by
    mucking about with initcall ordering which is a complete hack, and
    doesn't even remotely handle the case where device drivers are in
    modules. This approach completely sidesteps the issues by allowing
    driver registration to occur in any order, and any driver can request
    to be retried after a few more other drivers get probed.

    v4: - Integrate Manjunath's addition of a separate workqueue
    - Change -EAGAIN to -EPROBE_DEFER for drivers to trigger deferral
    - Update comment blocks to reflect how the code really works
    v3: - Hold off workqueue scheduling until late_initcall so that the bulk
    of driver probes are complete before we start retrying deferred devices.
    - Tested with simple use cases. Still needs more testing though.
    Using it to get rid of the gpio early_initcall madness, or to replace
    the ASoC internal probe deferral code would be ideal.
    v2: - added locking so it should no longer be utterly broken in that regard
    - remove device from deferred list at device_del time.
    - Still completely untested with any real use case, but has been
    boot tested.

    Signed-off-by: Grant Likely
    Cc: Mark Brown
    Cc: Arnd Bergmann
    Cc: Dilan Lee
    Cc: Manjunath GKondaiah
    Cc: Alan Stern
    Cc: Tony Lindgren
    Cc: Alan Cox
    Reviewed-by: Mark Brown
    Acked-by: David Daney
    Reviewed-by: Arnd Bergmann
    Signed-off-by: Greg Kroah-Hartman

    Grant Likely
     

01 Jun, 2007

1 commit

17 Apr, 2005

1 commit

  • 1da177e4c   Linux-2.6.12-rc2 ... Browse Code »

    Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds