From: NeilBrown <neilb@suse.de>
To: Trond Myklebust <trond.myklebust@hammerspace.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Chuck Lever <chuck.lever@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mark Hemment <markhemm@googlemail.com>,
Christoph Hellwig <hch@infradead.org>,
David Howells <dhowells@redhat.com>
Cc: linux-nfs@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 10/21] VFS: Add FMODE_CAN_ODIRECT file flag
Date: Mon, 07 Feb 2022 15:46:01 +1100 [thread overview]
Message-ID: <164420916118.29374.18393494885904268956.stgit@noble.brown> (raw)
In-Reply-To: <164420889455.29374.17958998143835612560.stgit@noble.brown>
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.
Other filesystems which currently use noop_direct_IO could usefully be
changed to set this flag instead.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
---
drivers/block/loop.c | 4 ++--
fs/fcntl.c | 9 ++++-----
fs/nfs/file.c | 3 ++-
fs/open.c | 9 ++++-----
fs/overlayfs/file.c | 13 ++++---------
include/linux/fs.h | 3 +++
6 files changed, 19 insertions(+), 22 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 01cbbfc4e9e2..a2609dd79370 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -184,8 +184,8 @@ static void __loop_update_dio(struct loop_device *lo, bool dio)
*/
if (dio) {
if (queue_logical_block_size(lo->lo_queue) >= sb_bsize &&
- !(lo->lo_offset & dio_align) &&
- mapping->a_ops->direct_IO)
+ !(lo->lo_offset & dio_align) &&
+ (file->f_mode & FMODE_CAN_ODIRECT))
use_dio = true;
else
use_dio = false;
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 9c6c6a3e2de5..11e665242a76 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -56,11 +56,10 @@ static int setfl(int fd, struct file * filp, unsigned long arg)
arg |= O_NONBLOCK;
/* Pipe packetized mode is controlled by O_DIRECT flag */
- if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) {
- if (!filp->f_mapping || !filp->f_mapping->a_ops ||
- !filp->f_mapping->a_ops->direct_IO)
- return -EINVAL;
- }
+ if (!S_ISFIFO(inode->i_mode) &&
+ (arg & O_DIRECT) &&
+ !(filp->f_mode & FMODE_CAN_ODIRECT))
+ return -EINVAL;
if (filp->f_op->check_flags)
error = filp->f_op->check_flags(arg);
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 3dbef2c31567..9e2def045111 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -74,6 +74,8 @@ nfs_file_open(struct inode *inode, struct file *filp)
return res;
res = nfs_open(inode, filp);
+ if (res == 0)
+ filp->f_mode |= FMODE_CAN_ODIRECT;
return res;
}
@@ -535,7 +537,6 @@ const struct address_space_operations nfs_file_aops = {
.write_end = nfs_write_end,
.invalidatepage = nfs_invalidate_page,
.releasepage = nfs_release_page,
- .direct_IO = nfs_direct_IO,
#ifdef CONFIG_MIGRATION
.migratepage = nfs_migrate_page,
#endif
diff --git a/fs/open.c b/fs/open.c
index 9ff2f621b760..76ddf9014499 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -834,17 +834,16 @@ static int do_dentry_open(struct file *f,
if ((f->f_mode & FMODE_WRITE) &&
likely(f->f_op->write || f->f_op->write_iter))
f->f_mode |= FMODE_CAN_WRITE;
+ if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO)
+ f->f_mode |= FMODE_CAN_ODIRECT;
f->f_write_hint = WRITE_LIFE_NOT_SET;
f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
- /* NB: we're sure to have correct a_ops only after f_op->open */
- if (f->f_flags & O_DIRECT) {
- if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
- return -EINVAL;
- }
+ if ((f->f_flags & O_DIRECT) && !(f->f_mode & FMODE_CAN_ODIRECT))
+ return -EINVAL;
/*
* XXX: Huge page cache doesn't support writing yet. Drop all page
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index fa125feed0ff..9d69b4dbb8c4 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -82,11 +82,8 @@ static int ovl_change_flags(struct file *file, unsigned int flags)
if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))
return -EPERM;
- if (flags & O_DIRECT) {
- if (!file->f_mapping->a_ops ||
- !file->f_mapping->a_ops->direct_IO)
- return -EINVAL;
- }
+ if ((flags & O_DIRECT) && !(file->f_mode & FMODE_CAN_ODIRECT))
+ return -EINVAL;
if (file->f_op->check_flags) {
err = file->f_op->check_flags(flags);
@@ -306,8 +303,7 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
ret = -EINVAL;
if (iocb->ki_flags & IOCB_DIRECT &&
- (!real.file->f_mapping->a_ops ||
- !real.file->f_mapping->a_ops->direct_IO))
+ !(real.file->f_mode & FMODE_CAN_ODIRECT))
goto out_fdput;
old_cred = ovl_override_creds(file_inode(file)->i_sb);
@@ -367,8 +363,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
ret = -EINVAL;
if (iocb->ki_flags & IOCB_DIRECT &&
- (!real.file->f_mapping->a_ops ||
- !real.file->f_mapping->a_ops->direct_IO))
+ !(real.file->f_mode & FMODE_CAN_ODIRECT))
goto out_fdput;
if (!ovl_should_sync(OVL_FS(inode->i_sb)))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 57e3b387cb17..c34c53267415 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -161,6 +161,9 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
/* File is stream-like */
#define FMODE_STREAM ((__force fmode_t)0x200000)
+/* File supports DIRECT IO */
+#define FMODE_CAN_ODIRECT ((__force fmode_t)0x400000)
+
/* File was opened by fanotify and shouldn't generate fanotify events */
#define FMODE_NONOTIFY ((__force fmode_t)0x4000000)
next prev parent reply other threads:[~2022-02-07 4:48 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-07 4:46 [PATCH 00/21 V4] Repair SWAP-over_NFS NeilBrown
2022-02-07 4:46 ` [PATCH 03/21] MM: move responsibility for setting SWP_FS_OPS to ->swap_activate NeilBrown
2022-02-07 4:46 ` [PATCH 07/21] DOC: update documentation for swap_activate and swap_rw NeilBrown
2022-02-07 4:46 ` [PATCH 18/21] NFSv4: keep state manager thread active if swap is enabled NeilBrown
2022-02-07 4:46 ` [PATCH 16/21] NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS NeilBrown
2022-02-07 4:46 ` NeilBrown [this message]
2022-02-07 4:46 ` [PATCH 06/21] MM: perform async writes to SWP_FS_OPS swap-space using ->swap_rw NeilBrown
2022-02-07 4:46 ` [PATCH 01/21] MM: create new mm/swap.h header file NeilBrown
2022-02-10 3:24 ` [PATCH 01/21 - revised] " NeilBrown
2022-02-10 15:19 ` [PATCH 01/21] " Geert Uytterhoeven
2022-02-14 23:50 ` NeilBrown
2022-02-07 4:46 ` [PATCH 09/21] MM: submit multipage write for SWP_FS_OPS swap-space NeilBrown
2022-02-07 8:40 ` Christoph Hellwig
2022-02-07 4:46 ` [PATCH 13/21] SUNRPC/auth: async tasks mustn't block waiting for memory NeilBrown
2022-02-07 4:46 ` [PATCH 02/21] MM: drop swap_set_page_dirty NeilBrown
2022-02-07 4:46 ` [PATCH 04/21] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space NeilBrown
2022-02-07 4:46 ` [PATCH 14/21] SUNRPC/xprt: async tasks mustn't block waiting for memory NeilBrown
2022-02-07 4:46 ` [PATCH 21/21] NFS: swap-out must always use STABLE writes NeilBrown
2022-02-07 4:46 ` [PATCH 11/21] NFS: remove IS_SWAPFILE hack NeilBrown
2022-02-07 4:46 ` [PATCH 05/21] MM: introduce ->swap_rw and use it for reads from SWP_FS_OPS swap-space NeilBrown
2022-02-07 4:46 ` [PATCH 08/21] MM: submit multipage reads for " NeilBrown
2022-02-07 4:46 ` [PATCH 20/21] NFS: swap IO handling is slightly different for O_DIRECT IO NeilBrown
2022-02-07 4:46 ` [PATCH 17/21] SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NeilBrown
2022-02-07 15:53 ` Chuck Lever III
2022-02-07 4:46 ` [PATCH 12/21] SUNRPC/call_alloc: async tasks mustn't block waiting for memory NeilBrown
2022-02-07 4:46 ` [PATCH 15/21] SUNRPC: remove scheduling boost for "SWAPPER" tasks NeilBrown
2022-02-07 4:46 ` [PATCH 19/21] NFS: rename nfs_direct_IO and use as ->swap_rw NeilBrown
2022-02-10 15:22 ` [PATCH 00/21 V4] Repair SWAP-over_NFS Geert Uytterhoeven
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