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>

1 files changed, 11 insertions, 37 deletions

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index d554e86abbe3..32ae8b49a72c 100644
--- 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;