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authorNeilBrown <neilb@suse.de>2022-05-10 04:20:49 +0300
committerakpm <akpm@linux-foundation.org>2022-05-10 04:20:49 +0300
commita2ad63daa88b9d6846976fd2a0b5e4f5cfc58377 (patch)
treeb9f241f9b747df5b8604ec839e1de51fd67891b5
parent6341a446a0e66355d729b663d7c8ca28ad6d1442 (diff)
downloadlinux-a2ad63daa88b9d6846976fd2a0b5e4f5cfc58377.tar.xz
VFS: add FMODE_CAN_ODIRECT file flag
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. Link: https://lkml.kernel.org/r/164859778128.29473.15189737957277399416.stgit@noble.brown Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: NeilBrown <neilb@suse.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--drivers/block/loop.c4
-rw-r--r--fs/fcntl.c9
-rw-r--r--fs/nfs/file.c3
-rw-r--r--fs/open.c9
-rw-r--r--fs/overlayfs/file.c13
-rw-r--r--include/linux/fs.h3
6 files changed, 19 insertions, 22 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index a58595f5ee2c..75ef2e177e1b 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -186,8 +186,8 @@ 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 f15d885b9796..34a3faa4886d 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 0e7686a5d0de..bfb4b707b07e 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -69,6 +69,8 @@ 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;
}
@@ -536,7 +538,6 @@ const struct address_space_operations nfs_file_aops = {
.write_end = nfs_write_end,
.invalidate_folio = nfs_invalidate_folio,
.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 1315253e0247..7b50d7a2f51d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -834,16 +834,15 @@ 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_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 dbc5d10328df..b81cacc51d2f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -162,6 +162,9 @@ 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)