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| author |   NeilBrown <neilb@suse.de> | 2022-05-09 18:20:49 -0700 |
|---|---|---|
| committer |   akpm <akpm@linux-foundation.org> | 2022-05-09 18:20:49 -0700 |
| commit | a2ad63daa88b9d6846976fd2a0b5e4f5cfc58377 (patch) | |
| tree | b9f241f9b747df5b8604ec839e1de51fd67891b5 /fs/fcntl.c | |
| parent | MM: handle THP in swap_*page_fs() - count_vm_events() (diff) | |
| download | wireguard-linux-a2ad63daa88b9d6846976fd2a0b5e4f5cfc58377.tar.xz wireguard-linux-a2ad63daa88b9d6846976fd2a0b5e4f5cfc58377.zip | |
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>
Diffstat (limited to 'fs/fcntl.c')
| -rw-r--r-- | fs/fcntl.c | 9 |
1 files changed, 4 insertions, 5 deletions
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); |