1 files changed, 65 insertions, 146 deletions

diff --git a/fs/open.c b/fs/open.c
index 1540632d8387..1e914b397e12 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -537,25 +537,6 @@ static int chown_common(struct path *path, uid_t user, gid_t group)
         return error;
 }
 
-SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
-{
-        struct path path;
-        int error;
-
-        error = user_path(filename, &path);
-        if (error)
-                goto out;
-        error = mnt_want_write(path.mnt);
-        if (error)
-                goto out_release;
-        error = chown_common(&path, user, group);
-        mnt_drop_write(path.mnt);
-out_release:
-        path_put(&path);
-out:
-        return error;
-}
-
 SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
                 gid_t, group, int, flag)
 {
@@ -583,23 +564,15 @@ out:
         return error;
 }
 
-SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
 {
-        struct path path;
-        int error;
+        return sys_fchownat(AT_FDCWD, filename, user, group, 0);
+}
 
-        error = user_lpath(filename, &path);
-        if (error)
-                goto out;
-        error = mnt_want_write(path.mnt);
-        if (error)
-                goto out_release;
-        error = chown_common(&path, user, group);
-        mnt_drop_write(path.mnt);
-out_release:
-        path_put(&path);
-out:
-        return error;
+SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+{
+        return sys_fchownat(AT_FDCWD, filename, user, group,
+                            AT_SYMLINK_NOFOLLOW);
 }
 
 SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
@@ -667,10 +640,9 @@ int open_check_o_direct(struct file *f)
         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 int do_dentry_open(struct file *f,
+                          int (*open)(struct inode *, struct file *),
+                          const struct cred *cred)
 {
         static const struct file_operations empty_fops = {};
         struct inode *inode;
@@ -682,9 +654,9 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
         if (unlikely(f->f_flags & O_PATH))
                 f->f_mode = FMODE_PATH;
 
-        inode = dentry->d_inode;
+        inode = f->f_path.dentry->d_inode;
         if (f->f_mode & FMODE_WRITE) {
-                error = __get_file_write_access(inode, mnt);
+                error = __get_file_write_access(inode, f->f_path.mnt);
                 if (error)
                         goto cleanup_file;
                 if (!special_file(inode->i_mode))
@@ -692,14 +664,12 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
         }
 
         f->f_mapping = inode->i_mapping;
-        f->f_path.dentry = dentry;
-        f->f_path.mnt = mnt;
         f->f_pos = 0;
         file_sb_list_add(f, inode->i_sb);
 
         if (unlikely(f->f_mode & FMODE_PATH)) {
                 f->f_op = &empty_fops;
-                return f;
+                return 0;
         }
 
         f->f_op = fops_get(inode->i_fop);
@@ -726,10 +696,11 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 
         file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
 
-        return f;
+        return 0;
 
 cleanup_all:
         fops_put(f->f_op);
+        file_sb_list_del(f);
         if (f->f_mode & FMODE_WRITE) {
                 put_write_access(inode);
                 if (!special_file(inode->i_mode)) {
@@ -740,124 +711,62 @@ cleanup_all:
                          * here, so just reset the state.
                          */
                         file_reset_write(f);
-                        mnt_drop_write(mnt);
+                        mnt_drop_write(f->f_path.mnt);
                 }
         }
-        file_sb_list_del(f);
-        f->f_path.dentry = NULL;
-        f->f_path.mnt = NULL;
 cleanup_file:
-        dput(dentry);
-        mntput(mnt);
-        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);
-                }
-        } else {
-                put_filp(f);
-        }
-        return res;
+        path_put(&f->f_path);
+        f->f_path.mnt = NULL;
+        f->f_path.dentry = NULL;
+        return error;
 }
 
 /**
- * lookup_instantiate_filp - instantiates the open intent filp
- * @nd: pointer to nameidata
+ * finish_open - finish opening a file
+ * @od: opaque open data
  * @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.
- * Beware of calling it for non-regular files! Those ->open methods might block
- * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
- * leading to a deadlock, as nobody can open that fifo anymore, because
- * another process to open fifo will block on locked parent when doing lookup).
- * Note that in case of error, nd->intent.open.file is destroyed, but the
- * path information remains valid.
+ * This can be used to finish opening a file passed to i_op->atomic_open().
+ *
  * 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 *))
+int finish_open(struct file *file, struct dentry *dentry,
+                int (*open)(struct inode *, struct file *),
+                int *opened)
 {
-        const struct cred *cred = current_cred();
+        int error;
+        BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
 
-        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->path.mnt),
-                                             nd->intent.open.file,
-                                             open, cred);
-out:
-        return nd->intent.open.file;
-out_err:
-        release_open_intent(nd);
-        nd->intent.open.file = ERR_CAST(dentry);
-        goto out;
+        mntget(file->f_path.mnt);
+        file->f_path.dentry = dget(dentry);
+
+        error = do_dentry_open(file, open, current_cred());
+        if (!error)
+                *opened |= FILE_OPENED;
+
+        return error;
 }
-EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
+EXPORT_SYMBOL(finish_open);
 
 /**
- * nameidata_to_filp - convert a nameidata to an open filp.
- * @nd: pointer to nameidata
- * @flags: open flags
+ * finish_no_open - finish ->atomic_open() without opening the file
+ *
+ * @od: opaque open data
+ * @dentry: dentry or NULL (as returned from ->lookup())
  *
- * Note that this function destroys the original nameidata
+ * This can be used to set the result of a successful lookup in ->atomic_open().
+ * The filesystem's atomic_open() method shall return NULL after calling this.
  */
-struct file *nameidata_to_filp(struct nameidata *nd)
+int finish_no_open(struct file *file, struct dentry *dentry)
 {
-        const struct cred *cred = current_cred();
-        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_path.dentry != NULL) {
-                nd->intent.open.file = NULL;
-        } else {
-                struct file *res;
-
-                path_get(&nd->path);
-                res = do_dentry_open(nd->path.dentry, nd->path.mnt,
-                                     filp, NULL, cred);
-                if (!IS_ERR(res)) {
-                        int error;
-
-                        nd->intent.open.file = NULL;
-                        BUG_ON(res != filp);
-
-                        error = open_check_o_direct(filp);
-                        if (error) {
-                                fput(filp);
-                                filp = ERR_PTR(error);
-                        }
-                } else {
-                        /* Allow nd->intent.open.file to be recycled */
-                        filp = res;
-                }
-        }
-        return filp;
+        file->f_path.dentry = dentry;
+        return 1;
 }
+EXPORT_SYMBOL(finish_no_open);
 
-/*
- * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
- * error.
- */
-struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
+struct file *dentry_open(const struct path *path, int flags,
                          const struct cred *cred)
 {
         int error;
@@ -866,18 +775,28 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
         validate_creds(cred);
 
         /* We must always pass in a valid mount pointer. */
-        BUG_ON(!mnt);
+        BUG_ON(!path->mnt);
 
         error = -ENFILE;
         f = get_empty_filp();
-        if (f == NULL) {
-                dput(dentry);
-                mntput(mnt);
+        if (f == NULL)
                 return ERR_PTR(error);
-        }
 
         f->f_flags = flags;
-        return __dentry_open(dentry, mnt, f, NULL, cred);
+        f->f_path = *path;
+        path_get(&f->f_path);
+        error = do_dentry_open(f, NULL, cred);
+        if (!error) {
+                error = open_check_o_direct(f);
+                if (error) {
+                        fput(f);
+                        f = ERR_PTR(error);
+                }
+        } else { 
+                put_filp(f);
+                f = ERR_PTR(error);
+        }
+        return f;
 }
 EXPORT_SYMBOL(dentry_open);