From: "NeilBrown" <neilb@suse.de>
To: "Christoph Hellwig" <hch@infradead.org>
Cc: "Trond Myklebust" <trond.myklebust@hammerspace.com>,
"Anna Schumaker" <anna.schumaker@netapp.com>,
"Chuck Lever" <chuck.lever@oracle.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Mel Gorman" <mgorman@suse.de>,
"Christoph Hellwig" <hch@infradead.org>,
"David Howells" <dhowells@redhat.com>,
linux-nfs@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 11/23] VFS: Add FMODE_CAN_ODIRECT file flag
Date: Thu, 27 Jan 2022 09:14:41 +1100 [thread overview]
Message-ID: <164323528189.5493.7196087998245554506@noble.neil.brown.name> (raw)
In-Reply-To: <Ye5puPat8w9/nQ6R@infradead.org>
On Mon, 24 Jan 2022, Christoph Hellwig wrote:
> On Mon, Jan 24, 2022 at 02:48:32PM +1100, NeilBrown wrote:
> > Currently various places test if direct IO is possible on a file by
> > checking for the existence of the direct_IO address space operation.
> > This is a poor choice, as the direct_IO operation may not be used - it is
> > only used if the generic_file_*_iter functions are called for direct IO
> > and some filesystems - particularly NFS - don't do this.
> >
> > Instead, introduce a new f_mode flag: FMODE_CAN_ODIRECT and change the
> > various places to check this (avoiding pointer dereferences).
> > do_dentry_open() will set this flag if ->direct_IO is present, so
> > filesystems do not need to be changed.
> >
> > NFS *is* changed, to set the flag explicitly and discard the direct_IO
> > entry in the address_space_operations for files.
>
> Looks good:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
>
> It would be nice to throw in a cleanup to remove noop_direct_IO as well.
I don't want to add this to the present series. When it lands I'll send
patches to the various filesystems to switch to using FMODE_CAN_ODIRECT.
Thanks,
NeilBrown
next prev parent reply other threads:[~2022-01-26 22:14 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 3:48 [PATCH 00/23 V3] Repair SWAP-over_NFS NeilBrown
2022-01-24 3:48 ` [PATCH 05/23] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space NeilBrown
2022-01-24 7:31 ` Christoph Hellwig
2022-01-24 3:48 ` [PATCH 03/23] MM: drop swap_set_page_dirty NeilBrown
2022-01-24 7:28 ` Christoph Hellwig
2022-01-24 3:48 ` [PATCH 14/23] NFS: swap IO handling is slightly different for O_DIRECT IO NeilBrown
2022-01-24 8:58 ` Christoph Hellwig
2022-01-24 13:22 ` Mark Hemment
2022-01-26 22:51 ` NeilBrown
2022-01-24 3:48 ` [PATCH 22/23] NFS: swap-out must always use STABLE writes NeilBrown
2022-01-26 3:45 ` Trond Myklebust
2022-01-26 21:42 ` NeilBrown
2022-01-24 3:48 ` [PATCH 23/23] SUNRPC: lock against ->sock changing during sysfs read NeilBrown
2022-01-24 3:48 ` [PATCH 08/23] DOC: update documentation for swap_activate and swap_rw NeilBrown
2022-01-24 8:50 ` Christoph Hellwig
2022-01-24 3:48 ` [PATCH 07/23] MM: perform async writes to SWP_FS_OPS swap-space using ->swap_rw NeilBrown
2022-01-24 8:49 ` Christoph Hellwig
2022-01-24 3:48 ` [PATCH 02/23] MM: extend block-plugging to cover all swap reads with read-ahead NeilBrown
2022-01-24 7:27 ` Christoph Hellwig
2022-01-26 21:47 ` NeilBrown
2022-01-26 23:09 ` Hugh Dickins
2022-01-27 0:32 ` NeilBrown
2022-01-24 3:48 ` [PATCH 16/23] SUNRPC/auth: async tasks mustn't block waiting for memory NeilBrown
2022-01-24 3:48 ` [PATCH 04/23] MM: move responsibility for setting SWP_FS_OPS to ->swap_activate NeilBrown
2022-01-24 7:30 ` Christoph Hellwig
2022-01-24 3:48 ` [PATCH 06/23] MM: introduce ->swap_rw and use it for reads from SWP_FS_OPS swap-space NeilBrown
2022-01-24 8:48 ` Christoph Hellwig
2022-01-24 3:48 ` [PATCH 15/23] SUNRPC/call_alloc: async tasks mustn't block waiting for memory NeilBrown
2022-01-24 3:48 ` [PATCH 20/23] SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NeilBrown
2022-01-24 3:48 ` [PATCH 01/23] MM: create new mm/swap.h header file NeilBrown
2022-02-07 13:51 ` Geert Uytterhoeven
2022-01-24 3:48 ` [PATCH 09/23] MM: submit multipage reads for SWP_FS_OPS swap-space NeilBrown
2022-01-24 8:25 ` kernel test robot
2022-01-24 8:52 ` Christoph Hellwig
2022-01-24 9:27 ` kernel test robot
2022-01-24 13:16 ` Mark Hemment
2022-01-26 22:04 ` NeilBrown
2022-02-08 11:07 ` Geert Uytterhoeven
2022-01-24 3:48 ` [PATCH 12/23] NFS: remove IS_SWAPFILE hack NeilBrown
2022-01-24 8:56 ` Christoph Hellwig
2022-01-24 3:48 ` [PATCH 19/23] NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS NeilBrown
2022-01-24 3:48 ` [PATCH 17/23] SUNRPC/xprt: async tasks mustn't block waiting for memory NeilBrown
2022-01-24 3:48 ` [PATCH 18/23] SUNRPC: remove scheduling boost for "SWAPPER" tasks NeilBrown
2022-01-24 3:48 ` [PATCH 21/23] NFSv4: keep state manager thread active if swap is enabled NeilBrown
2022-01-24 3:48 ` [PATCH 11/23] VFS: Add FMODE_CAN_ODIRECT file flag NeilBrown
2022-01-24 8:56 ` Christoph Hellwig
2022-01-26 22:14 ` NeilBrown [this message]
2022-01-24 3:48 ` [PATCH 10/23] MM: submit multipage write for SWP_FS_OPS swap-space NeilBrown
2022-01-24 8:55 ` Christoph Hellwig
2022-01-24 10:29 ` kernel test robot
2022-01-24 3:48 ` [PATCH 13/23] NFS: rename nfs_direct_IO and use as ->swap_rw NeilBrown
2022-01-24 8:57 ` Christoph Hellwig
2022-02-07 17:55 ` [PATCH 00/23 V3] Repair SWAP-over_NFS Geert Uytterhoeven
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