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From: Christoph Hellwig <hch@infradead.org>
To: NeilBrown <neilb@suse.de>
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 08/18] MM: Add AS_CAN_DIO mapping flag
Date: Tue, 21 Dec 2021 00:46:19 -0800	[thread overview]
Message-ID: <YcGUWxqQts79Kv6B@infradead.org> (raw)
In-Reply-To: <163969850302.20885.17124747377211907111.stgit@noble.brown>

On Fri, Dec 17, 2021 at 10:48:23AM +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 mapping flag: AS_CAN_DIO and change the various
> places to check this (avoiding a pointer dereference).
> unlock_new_inode() 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.

For other can flags related to file operations we usuall stash them into
file->f_mode.  Any reason to treat this different?

  parent reply	other threads:[~2021-12-21  8:46 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-16 23:48 [PATCH 00/18 V2] Repair SWAP-over-NFS NeilBrown
2021-12-16 23:48 ` [PATCH 05/18] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space NeilBrown
2021-12-17  8:51   ` kernel test robot
2021-12-17  8:51     ` kernel test robot
2021-12-21  8:43   ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 01/18] Structural cleanup for filesystem-based swap NeilBrown
2021-12-17 10:33   ` kernel test robot
2021-12-17 10:33     ` kernel test robot
2021-12-21  8:34   ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 03/18] MM: use ->swap_rw for reads from SWP_FS_OPS swap-space NeilBrown
2021-12-20 12:16   ` Mark Hemment
2021-12-21  8:40   ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 02/18] MM: create new mm/swap.h header file NeilBrown
2021-12-17 10:03   ` kernel test robot
2021-12-17 10:03     ` kernel test robot
2021-12-21  8:36   ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 04/18] MM: perform async writes to SWP_FS_OPS swap-space NeilBrown
2021-12-21  8:41   ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 06/18] MM: submit multipage reads for " NeilBrown
2021-12-17  7:09   ` kernel test robot
2021-12-17  7:09     ` kernel test robot
2021-12-21  8:44   ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 17/18] NFSv4: keep state manager thread active if swap is enabled NeilBrown
2021-12-16 23:48 ` [PATCH 10/18] NFS: swap IO handling is slightly different for O_DIRECT IO NeilBrown
2021-12-20 15:02   ` Mark Hemment
2021-12-16 23:48 ` [PATCH 12/18] SUNRPC/auth: async tasks mustn't block waiting for memory NeilBrown
2021-12-16 23:48 ` [PATCH 15/18] NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS NeilBrown
2021-12-16 23:48 ` [PATCH 14/18] SUNRPC: remove scheduling boost for "SWAPPER" tasks NeilBrown
2021-12-16 23:48 ` [PATCH 13/18] SUNRPC/xprt: async tasks mustn't block waiting for memory NeilBrown
2021-12-16 23:48 ` [PATCH 11/18] SUNRPC/call_alloc: " NeilBrown
2021-12-16 23:48 ` [PATCH 16/18] SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NeilBrown
2021-12-16 23:48 ` [PATCH 08/18] MM: Add AS_CAN_DIO mapping flag NeilBrown
2021-12-19 13:38   ` Mark Hemment
2021-12-19 20:59     ` NeilBrown
2021-12-21  8:46   ` Christoph Hellwig [this message]
2022-01-19  3:54     ` NeilBrown
2021-12-16 23:48 ` [PATCH 07/18] MM: submit multipage write for SWP_FS_OPS swap-space NeilBrown
2021-12-20 12:21   ` Mark Hemment
2021-12-16 23:48 ` [PATCH 09/18] NFS: rename nfs_direct_IO and use as ->swap_rw NeilBrown
2021-12-16 23:48 ` [PATCH 18/18] NFS: swap-out must always use STABLE writes NeilBrown
2021-12-17 21:29 ` [PATCH 00/18 V2] Repair SWAP-over-NFS Anna Schumaker
2021-12-19 21:07   ` NeilBrown
2021-12-21  8:48     ` Christoph Hellwig

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