fat: Kill d_invalidate() in vfat_lookup()

d_invalidate() for positive dentry doesn't work in some cases
(vfsmount, nfsd, and maybe others). shrink_dcache_parent() by
d_invalidate() is pointless for vfat usage at all.

So, this kills it, and intead of it uses d_move().

To save old behavior, this returns alias simply for directory (don't
change pwd, etc..). the directory lookup shouldn't be important for
performance.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 7 deletions

diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index d585398f9f6b..bf326d4356a3 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -745,13 +745,12 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
                  *
                  * Switch to new one for reason of locality if possible.
                  */
-                if (d_invalidate(alias) == 0)
-                        dput(alias);
-                else {
-                        iput(inode);
-                        unlock_super(sb);
-                        return alias;
-                }
+                BUG_ON(d_unhashed(alias));
+                if (!S_ISDIR(inode->i_mode))
+                        d_move(alias, dentry);
+                iput(inode);
+                unlock_super(sb);
+                return alias;
         }
 out:
         unlock_super(sb);