1. 17 May, 2016 1 commit
    • Jeff Layton's avatar
      pnfs: rework LAYOUTGET retry handling · 183d9e7b
      Jeff Layton authored
      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: default avatarJeff Layton <jeff.layton@primarydata.com>
      Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      183d9e7b
  2. 08 May, 2013 1 commit
    • Zach Brown's avatar
      aio: remove retry-based AIO · 41003a7b
      Zach Brown authored
      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: default avatarKent Overstreet <koverstreet@google.com>
      Signed-off-by: default avatarZach Brown <zab@redhat.com>
      Cc: Zach Brown <zab@redhat.com>
      Cc: Felipe Balbi <balbi@ti.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Mark Fasheh <mfasheh@suse.com>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Asai Thambi S P <asamymuthupa@micron.com>
      Cc: Selvan Mani <smani@micron.com>
      Cc: Sam Bradshaw <sbradshaw@micron.com>
      Acked-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Benjamin LaHaise <bcrl@kvack.org>
      Reviewed-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      41003a7b
  3. 13 Oct, 2012 1 commit
  4. 01 Jun, 2012 1 commit
    • Miklos Szeredi's avatar
      vfs: retry last component if opening stale dentry · 16b1c1cd
      Miklos Szeredi authored
      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: default avatarMiklos Szeredi <mszeredi@suse.cz>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      16b1c1cd
  5. 08 Mar, 2012 1 commit
    • Grant Likely's avatar
      drivercore: Add driver probe deferral mechanism · d1c3414c
      Grant Likely authored
      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: default avatarGrant Likely <grant.likely@secretlab.ca>
      Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Dilan Lee <dilee@nvidia.com>
      Cc: Manjunath GKondaiah <manjunath.gkondaiah@linaro.org>
      Cc: Alan Stern <stern@rowland.harvard.edu>
      Cc: Tony Lindgren <tony@atomide.com>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Reviewed-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
      Acked-by: default avatarDavid Daney <david.daney@cavium.com>
      Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d1c3414c
  6. 01 Jun, 2007 1 commit
  7. 16 Apr, 2005 1 commit
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      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!
      1da177e4