cache the value of file_inode() in struct file

Note that this thing does *not* contribute to inode refcount;
it's pinned down by dentry.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4e686a099465..74a907b8b950 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -769,6 +769,7 @@ struct file {
         } f_u;
         struct path             f_path;
 #define f_dentry        f_path.dentry
+        struct inode            *f_inode;       /* cached value */
         const struct file_operations    *f_op;
 
         /*
@@ -2217,7 +2218,7 @@ static inline bool execute_ok(struct inode *inode)
 
 static inline struct inode *file_inode(struct file *f)
 {
-        return f->f_path.dentry->d_inode;
+        return f->f_inode;
 }
 
 /*