ovl: store ovl_entry in inode->i_private for all inodes

Previously this was only done for directory inodes.  Doing so for all
inodes makes for a nice cleanup in ovl_permission at zero cost.

Inodes are not shared for hard links on the overlay, so this works fine.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index d554e86..32ae8b4 100644 (file)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -109,31 +109,12 @@ static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
 
 int ovl_permission(struct inode *inode, int mask)
 {
-       struct ovl_entry *oe;
-       struct dentry *alias = NULL;
-       struct inode *realinode;
-       struct dentry *realdentry;
+       struct ovl_entry *oe = inode->i_private;
        bool is_upper;
+       struct dentry *realdentry = ovl_entry_real(oe, &is_upper);
+       struct inode *realinode;
        int err;
 
-       if (S_ISDIR(inode->i_mode)) {
-               oe = inode->i_private;
-       } else if (mask & MAY_NOT_BLOCK) {
-               return -ECHILD;
-       } else {
-               /*
-                * For non-directories find an alias and get the info
-                * from there.
-                */
-               alias = d_find_any_alias(inode);
-               if (WARN_ON(!alias))
-                       return -ENOENT;
-
-               oe = alias->d_fsdata;
-       }
-
-       realdentry = ovl_entry_real(oe, &is_upper);
-
        if (ovl_is_default_permissions(inode)) {
                struct kstat stat;
                struct path realpath = { .dentry = realdentry };
@@ -145,26 +126,23 @@ int ovl_permission(struct inode *inode, int mask)
 
                err = vfs_getattr(&realpath, &stat);
                if (err)
-                       goto out_dput;
+                       return err;
 
-               err = -ESTALE;
                if ((stat.mode ^ inode->i_mode) & S_IFMT)
-                       goto out_dput;
+                       return -ESTALE;
 
                inode->i_mode = stat.mode;
                inode->i_uid = stat.uid;
                inode->i_gid = stat.gid;
 
-               err = generic_permission(inode, mask);
-               goto out_dput;
+               return generic_permission(inode, mask);
        }
 
        /* Careful in RCU walk mode */
-       realinode = ACCESS_ONCE(realdentry->d_inode);
+       realinode = d_inode_rcu(realdentry);
        if (!realinode) {
                WARN_ON(!(mask & MAY_NOT_BLOCK));
-               err = -ENOENT;
-               goto out_dput;
+               return -ENOENT;
        }
 
        if (mask & MAY_WRITE) {
@@ -183,16 +161,12 @@ int ovl_permission(struct inode *inode, int mask)
                 * constructed return EROFS to prevent modification of
                 * upper layer.
                 */
-               err = -EROFS;
                if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) &&
                    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
-                       goto out_dput;
+                       return -EROFS;
        }
 
-       err = __inode_permission(realinode, mask);
-out_dput:
-       dput(alias);
-       return err;
+       return __inode_permission(realinode, mask);
 }
 
 static const char *ovl_get_link(struct dentry *dentry,
@@ -405,11 +379,11 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
        inode->i_ino = get_next_ino();
        inode->i_mode = mode;
        inode->i_flags |= S_NOATIME | S_NOCMTIME;
+       inode->i_private = oe;
 
        mode &= S_IFMT;
        switch (mode) {
        case S_IFDIR:
-               inode->i_private = oe;
                inode->i_op = &ovl_dir_inode_operations;
                inode->i_fop = &ovl_dir_operations;
                break;