[PATCH] memory hotplug: sysfs and add/remove functions

[pandora-kernel.git] / fs / open.c

diff --git a/fs/open.c b/fs/open.c
index f0d90cf..8d06ec9 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -739,7 +739,8 @@ asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
 }
 
 static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
-                                       int flags, struct file *f)
+                                       int flags, struct file *f,
+                                       int (*open)(struct inode *, struct file *))
 {
        struct inode *inode;
        int error;
@@ -761,11 +762,14 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
        f->f_op = fops_get(inode->i_fop);
        file_move(f, &inode->i_sb->s_files);
 
-       if (f->f_op && f->f_op->open) {
-               error = f->f_op->open(inode,f);
+       if (!open && f->f_op)
+               open = f->f_op->open;
+       if (open) {
+               error = open(inode, f);
                if (error)
                        goto cleanup_all;
        }
+
        f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 
        file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
@@ -814,28 +818,75 @@ struct file *filp_open(const char * filename, int flags, int mode)
 {
        int namei_flags, error;
        struct nameidata nd;
-       struct file *f;
 
        namei_flags = flags;
        if ((namei_flags+1) & O_ACCMODE)
                namei_flags++;
-       if (namei_flags & O_TRUNC)
-               namei_flags |= 2;
-
-       error = -ENFILE;
-       f = get_empty_filp();
-       if (f == NULL)
-               return ERR_PTR(error);
 
        error = open_namei(filename, namei_flags, mode, &nd);
        if (!error)
-               return __dentry_open(nd.dentry, nd.mnt, flags, f);
+               return nameidata_to_filp(&nd, flags);
 
-       put_filp(f);
        return ERR_PTR(error);
 }
 EXPORT_SYMBOL(filp_open);
 
+/**
+ * lookup_instantiate_filp - instantiates the open intent filp
+ * @nd: pointer to nameidata
+ * @dentry: pointer to dentry
+ * @open: open callback
+ *
+ * Helper for filesystems that want to use lookup open intents and pass back
+ * a fully instantiated struct file to the caller.
+ * This function is meant to be called from within a filesystem's
+ * lookup method.
+ * Note that in case of error, nd->intent.open.file is destroyed, but the
+ * path information remains valid.
+ * If the open callback is set to NULL, then the standard f_op->open()
+ * filesystem callback is substituted.
+ */
+struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
+               int (*open)(struct inode *, struct file *))
+{
+       if (IS_ERR(nd->intent.open.file))
+               goto out;
+       if (IS_ERR(dentry))
+               goto out_err;
+       nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->mnt),
+                                            nd->intent.open.flags - 1,
+                                            nd->intent.open.file,
+                                            open);
+out:
+       return nd->intent.open.file;
+out_err:
+       release_open_intent(nd);
+       nd->intent.open.file = (struct file *)dentry;
+       goto out;
+}
+EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
+
+/**
+ * nameidata_to_filp - convert a nameidata to an open filp.
+ * @nd: pointer to nameidata
+ * @flags: open flags
+ *
+ * Note that this function destroys the original nameidata
+ */
+struct file *nameidata_to_filp(struct nameidata *nd, int flags)
+{
+       struct file *filp;
+
+       /* Pick up the filp from the open intent */
+       filp = nd->intent.open.file;
+       /* Has the filesystem initialised the file for us? */
+       if (filp->f_dentry == NULL)
+               filp = __dentry_open(nd->dentry, nd->mnt, flags, filp, NULL);
+       else
+               path_release(nd);
+       return filp;
+}
+
 struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
 {
        int error;
@@ -846,7 +897,7 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
        if (f == NULL)
                return ERR_PTR(error);
 
-       return __dentry_open(dentry, mnt, flags, f);
+       return __dentry_open(dentry, mnt, flags, f, NULL);
 }
 EXPORT_SYMBOL(dentry_open);