4 files changed, 58 insertions, 27 deletions

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 2f7951d67d16..cc1d01365905 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -295,7 +295,9 @@ struct dentry *autofs4_expire_direct(struct super_block *sb,
                 struct autofs_info *ino = autofs4_dentry_ino(root);
                 if (d_mountpoint(root)) {
                         ino->flags |= AUTOFS_INF_MOUNTPOINT;
-                        root->d_mounted--;
+                        spin_lock(&root->d_lock);
+                        root->d_flags &= ~DCACHE_MOUNTED;
+                        spin_unlock(&root->d_lock);
                 }
                 ino->flags |= AUTOFS_INF_EXPIRING;
                 init_completion(&ino->expire_complete);
@@ -503,7 +505,14 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 
                 spin_lock(&sbi->fs_lock);
                 if (ino->flags & AUTOFS_INF_MOUNTPOINT) {
-                        sb->s_root->d_mounted++;
+                        spin_lock(&sb->s_root->d_lock);
+                        /*
+                         * If we haven't been expired away, then reset
+                         * mounted status.
+                         */
+                        if (mnt->mnt_parent != mnt)
+                                sb->s_root->d_flags |= DCACHE_MOUNTED;
+                        spin_unlock(&sb->s_root->d_lock);
                         ino->flags &= ~AUTOFS_INF_MOUNTPOINT;
                 }
                 ino->flags &= ~AUTOFS_INF_EXPIRING;
diff --git a/fs/dcache.c b/fs/dcache.c
index 187fea040108..1d5cf511e1c7 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1265,7 +1265,6 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
         dentry->d_sb = NULL;
         dentry->d_op = NULL;
         dentry->d_fsdata = NULL;
-        dentry->d_mounted = 0;
         INIT_HLIST_NODE(&dentry->d_hash);
         INIT_LIST_HEAD(&dentry->d_lru);
         INIT_LIST_HEAD(&dentry->d_subdirs);
diff --git a/fs/namespace.c b/fs/namespace.c
index 3dbfc072ec70..39a7d507fba0 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -492,6 +492,27 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns)
 }
 
 /*
+ * Clear dentry's mounted state if it has no remaining mounts.
+ * vfsmount_lock must be held for write.
+ */
+static void dentry_reset_mounted(struct vfsmount *mnt, struct dentry *dentry)
+{
+        unsigned u;
+
+        for (u = 0; u < HASH_SIZE; u++) {
+                struct vfsmount *p;
+
+                list_for_each_entry(p, &mount_hashtable[u], mnt_hash) {
+                        if (p->mnt_mountpoint == dentry)
+                                return;
+                }
+        }
+        spin_lock(&dentry->d_lock);
+        dentry->d_flags &= ~DCACHE_MOUNTED;
+        spin_unlock(&dentry->d_lock);
+}
+
+/*
  * vfsmount lock must be held for write
  */
 static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
@@ -502,7 +523,7 @@ static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
         mnt->mnt_mountpoint = mnt->mnt_root;
         list_del_init(&mnt->mnt_child);
         list_del_init(&mnt->mnt_hash);
-        old_path->dentry->d_mounted--;
+        dentry_reset_mounted(old_path->mnt, old_path->dentry);
 }
 
 /*
@@ -513,7 +534,9 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
 {
         child_mnt->mnt_parent = mntget(mnt);
         child_mnt->mnt_mountpoint = dget(dentry);
-        dentry->d_mounted++;
+        spin_lock(&dentry->d_lock);
+        dentry->d_flags |= DCACHE_MOUNTED;
+        spin_unlock(&dentry->d_lock);
 }
 
 /*
@@ -1073,7 +1096,7 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
                 list_del_init(&p->mnt_child);
                 if (p->mnt_parent != p) {
                         p->mnt_parent->mnt_ghosts++;
-                        p->mnt_mountpoint->d_mounted--;
+                        dentry_reset_mounted(p->mnt_parent, p->mnt_mountpoint);
                 }
                 change_mnt_propagation(p, MS_PRIVATE);
         }
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index c2e7390289cc..e4414693065e 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -92,7 +92,6 @@ struct dentry {
         unsigned int d_flags;           /* protected by d_lock */
         spinlock_t d_lock;              /* per dentry lock */
         seqcount_t d_seq;               /* per dentry seqlock */
-        int d_mounted;
         struct inode *d_inode;          /* Where the name belongs to - NULL is
                                          * negative */
         /*
@@ -156,33 +155,34 @@ struct dentry_operations {
 
 /* d_flags entries */
 #define DCACHE_AUTOFS_PENDING 0x0001    /* autofs: "under construction" */
-#define DCACHE_NFSFS_RENAMED  0x0002    /* this dentry has been "silly
-                                         * renamed" and has to be
-                                         * deleted on the last dput()
-                                         */
-#define DCACHE_DISCONNECTED 0x0004
-     /* This dentry is possibly not currently connected to the dcache tree,
-      * in which case its parent will either be itself, or will have this
-      * flag as well.  nfsd will not use a dentry with this bit set, but will
-      * first endeavour to clear the bit either by discovering that it is
-      * connected, or by performing lookup operations.   Any filesystem which
-      * supports nfsd_operations MUST have a lookup function which, if it finds
-      * a directory inode with a DCACHE_DISCONNECTED dentry, will d_move
-      * that dentry into place and return that dentry rather than the passed one,
-      * typically using d_splice_alias.
-      */
+#define DCACHE_NFSFS_RENAMED  0x0002
+     /* this dentry has been "silly renamed" and has to be deleted on the last
+      * dput() */
+
+#define DCACHE_DISCONNECTED     0x0004
+     /* This dentry is possibly not currently connected to the dcache tree, in
+      * which case its parent will either be itself, or will have this flag as
+      * well.  nfsd will not use a dentry with this bit set, but will first
+      * endeavour to clear the bit either by discovering that it is connected,
+      * or by performing lookup operations.   Any filesystem which supports
+      * nfsd_operations MUST have a lookup function which, if it finds a
+      * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
+      * dentry into place and return that dentry rather than the passed one,
+      * typically using d_splice_alias. */
 
 #define DCACHE_REFERENCED       0x0008  /* Recently used, don't discard. */
 #define DCACHE_UNHASHED         0x0010  
-
-#define DCACHE_INOTIFY_PARENT_WATCHED   0x0020 /* Parent inode is watched by inotify */
+#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020
+     /* Parent inode is watched by inotify */
 
 #define DCACHE_COOKIE           0x0040  /* For use by dcookie subsystem */
-
-#define DCACHE_FSNOTIFY_PARENT_WATCHED  0x0080 /* Parent inode is watched by some fsnotify listener */
+#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080
+     /* Parent inode is watched by some fsnotify listener */
 
 #define DCACHE_CANT_MOUNT       0x0100
 #define DCACHE_GENOCIDE         0x0200
+#define DCACHE_MOUNTED          0x0400  /* is a mountpoint */
+
 
 extern spinlock_t dcache_inode_lock;
 extern seqlock_t rename_lock;
@@ -372,7 +372,7 @@ extern void dput(struct dentry *);
 
 static inline int d_mountpoint(struct dentry *dentry)
 {
-        return dentry->d_mounted;
+        return dentry->d_flags & DCACHE_MOUNTED;
 }
 
 extern struct vfsmount *lookup_mnt(struct path *);