vfs: split __dentry_open()

Split __dentry_open() into two functions:

  do_dentry_open() - does most of the actual work, doesn't put file on failure
  open_check_o_direct() - after a successful open, checks direct_IO method

This will allow i_op->atomic_open to do just the file initialization and leave
the direct_IO checking to the VFS.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 33 insertions, 14 deletions

diff --git a/fs/open.c b/fs/open.c
index d54301219d04..9daa1cea52fc 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -654,10 +654,23 @@ static inline int __get_file_write_access(struct inode *inode,
         return error;
 }
 
-static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
-                                        struct file *f,
-                                        int (*open)(struct inode *, struct file *),
-                                        const struct cred *cred)
+int open_check_o_direct(struct file *f)
+{
+        /* 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) &&
+                    (!f->f_mapping->a_ops->get_xip_mem))) {
+                        return -EINVAL;
+                }
+        }
+        return 0;
+}
+
+static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
+                                   struct file *f,
+                                   int (*open)(struct inode *, struct file *),
+                                   const struct cred *cred)
 {
         static const struct file_operations empty_fops = {};
         struct inode *inode;
@@ -713,16 +726,6 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 
         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) &&
-                    (!f->f_mapping->a_ops->get_xip_mem))) {
-                        fput(f);
-                        f = ERR_PTR(-EINVAL);
-                }
-        }
-
         return f;
 
 cleanup_all:
@@ -750,6 +753,22 @@ cleanup_file:
         return ERR_PTR(error);
 }
 
+static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
+                                struct file *f,
+                                int (*open)(struct inode *, struct file *),
+                                const struct cred *cred)
+{
+        struct file *res = do_dentry_open(dentry, mnt, f, open, cred);
+        if (!IS_ERR(res)) {
+                int error = open_check_o_direct(f);
+                if (error) {
+                        fput(res);
+                        res = ERR_PTR(error);
+                }
+        }
+        return res;
+}
+
 /**
  * lookup_instantiate_filp - instantiates the open intent filp
  * @nd: pointer to nameidata