[PATCH 2/2] fuse: permit O_DIRECT flag in open()

[Anand Avati <avati-+FkPdpiNhgJBDgjK7y7TUQ@public.gmane.org>]

but do not permit setting of O_DIRECT flag via fcntl() (or unsetting)
---
 fs/fuse/file.c |   27 +++++++++++++++++++++++----
 1 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 82a6646..f30a7c6 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -154,6 +154,18 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 		return err;
 	}
 
+        if (file->f_flags & O_DIRECT) {
+                /* set fuse_direct_io_file_operations as fops in
+                   fuse_finish_open as though the FS enforced direct_io
+                */
+                outarg.open_flags |= FOPEN_DIRECT_IO;
+
+                /* make VFS believe we don't support O_DIRECT till we
+                   implement a_ops->direct_IO
+                */
+                file->f_flags &= ~O_DIRECT;
+        }
+
 	if (isdir)
 		outarg.open_flags &= ~FOPEN_DIRECT_IO;
 
@@ -193,10 +205,6 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	int err;
 
-	/* VFS checks this, but only _after_ ->open() */
-	if (file->f_flags & O_DIRECT)
-		return -EINVAL;
-
 	err = generic_file_open(inode, file);
 	if (err)
 		return err;
@@ -2132,6 +2140,15 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 	return 0;
 }
 
+
+static int fuse_check_flags(struct file *filp, int flags)
+{
+        if ((filp->f_flags ^ flags) & O_DIRECT)
+                return -EINVAL;
+	return 0;
+}
+
+
 static const struct file_operations fuse_file_operations = {
 	.llseek		= fuse_file_llseek,
 	.read		= do_sync_read,
@@ -2149,6 +2166,7 @@ static const struct file_operations fuse_file_operations = {
 	.unlocked_ioctl	= fuse_file_ioctl,
 	.compat_ioctl	= fuse_file_compat_ioctl,
 	.poll		= fuse_file_poll,
+        .check_flags    = fuse_check_flags,
 };
 
 static const struct file_operations fuse_direct_io_file_operations = {
@@ -2165,6 +2183,7 @@ static const struct file_operations fuse_direct_io_file_operations = {
 	.unlocked_ioctl	= fuse_file_ioctl,
 	.compat_ioctl	= fuse_file_compat_ioctl,
 	.poll		= fuse_file_poll,
+        .check_flags    = fuse_check_flags,
 	/* no splice_read */
 };
 
-- 
1.7.4.4


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