4 files changed, 59 insertions, 11 deletions

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index eea25934da62..00da71d0f32a 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -55,6 +55,7 @@ struct autofs_info {
 
         struct autofs_sb_info *sbi;
         unsigned long last_used;
+        atomic_t count;
 
         mode_t  mode;
         size_t  size;
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 165fe9e2d570..053d92a745b9 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -101,6 +101,7 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
                              unsigned long timeout,
                              int do_now)
 {
+        struct autofs_info *ino;
         struct dentry *p;
 
         DPRINTK("top %p %.*s",
@@ -110,14 +111,6 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
         if (!simple_positive(top))
                 return 1;
 
-        /* Timeout of a tree mount is determined by its top dentry */
-        if (!autofs4_can_expire(top, timeout, do_now))
-                return 1;
-
-        /* Is someone visiting anywhere in the tree ? */
-        if (may_umount_tree(mnt))
-                return 1;
-
         spin_lock(&dcache_lock);
         for (p = top; p; p = next_dentry(p, top)) {
                 /* Negative dentry - give up */
@@ -130,17 +123,40 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
                 p = dget(p);
                 spin_unlock(&dcache_lock);
 
+                /*
+                 * Is someone visiting anywhere in the subtree ?
+                 * If there's no mount we need to check the usage
+                 * count for the autofs dentry.
+                 */
+                ino = autofs4_dentry_ino(p);
                 if (d_mountpoint(p)) {
-                        /* First busy => tree busy */
                         if (autofs4_mount_busy(mnt, p)) {
                                 dput(p);
                                 return 1;
                         }
+                } else {
+                        unsigned int ino_count = atomic_read(&ino->count);
+
+                        /* allow for dget above and top is already dgot */
+                        if (p == top)
+                                ino_count += 2;
+                        else
+                                ino_count++;
+
+                        if (atomic_read(&p->d_count) > ino_count) {
+                                dput(p);
+                                return 1;
+                        }
                 }
                 dput(p);
                 spin_lock(&dcache_lock);
         }
         spin_unlock(&dcache_lock);
+
+        /* Timeout of a tree mount is ultimately determined by its top dentry */
+        if (!autofs4_can_expire(top, timeout, do_now))
+                return 1;
+
         return 0;
 }
 
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 1ad98d48e550..2335b1d6490f 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -46,6 +46,7 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
         ino->size = 0;
 
         ino->last_used = jiffies;
+        atomic_set(&ino->count, 0);
 
         ino->sbi = sbi;
 
@@ -64,10 +65,19 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
 
 void autofs4_free_ino(struct autofs_info *ino)
 {
+        struct autofs_info *p_ino;
+
         if (ino->dentry) {
                 ino->dentry->d_fsdata = NULL;
-                if (ino->dentry->d_inode)
+                if (ino->dentry->d_inode) {
+                        struct dentry *parent = ino->dentry->d_parent;
+                        if (atomic_dec_and_test(&ino->count)) {
+                                p_ino = autofs4_dentry_ino(parent);
+                                if (p_ino && parent != ino->dentry)
+                                        atomic_dec(&p_ino->count);
+                        }
                         dput(ino->dentry);
+                }
                 ino->dentry = NULL;
         }
         if (ino->free)
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index c7ff35774344..d196712c4b94 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -490,6 +490,7 @@ static int autofs4_dir_symlink(struct inode *dir,
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         struct inode *inode;
         char *cp;
 
@@ -523,6 +524,10 @@ static int autofs4_dir_symlink(struct inode *dir,
 
         dentry->d_fsdata = ino;
         ino->dentry = dget(dentry);
+        atomic_inc(&ino->count);
+        p_ino = autofs4_dentry_ino(dentry->d_parent);
+        if (p_ino && dentry->d_parent != dentry)
+                atomic_inc(&p_ino->count);
         ino->inode = inode;
 
         dir->i_mtime = CURRENT_TIME;
@@ -549,11 +554,17 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         
         /* This allows root to remove symlinks */
         if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
                 return -EACCES;
 
+        if (atomic_dec_and_test(&ino->count)) {
+                p_ino = autofs4_dentry_ino(dentry->d_parent);
+                if (p_ino && dentry->d_parent != dentry)
+                        atomic_dec(&p_ino->count);
+        }
         dput(ino->dentry);
 
         dentry->d_inode->i_size = 0;
@@ -570,6 +581,7 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         
         if (!autofs4_oz_mode(sbi))
                 return -EACCES;
@@ -584,8 +596,12 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
         spin_unlock(&dentry->d_lock);
         spin_unlock(&dcache_lock);
 
+        if (atomic_dec_and_test(&ino->count)) {
+                p_ino = autofs4_dentry_ino(dentry->d_parent);
+                if (p_ino && dentry->d_parent != dentry)
+                        atomic_dec(&p_ino->count);
+        }
         dput(ino->dentry);
-
         dentry->d_inode->i_size = 0;
         dentry->d_inode->i_nlink = 0;
 
@@ -599,6 +615,7 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         struct inode *inode;
 
         if ( !autofs4_oz_mode(sbi) )
@@ -621,6 +638,10 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
         dentry->d_fsdata = ino;
         ino->dentry = dget(dentry);
+        atomic_inc(&ino->count);
+        p_ino = autofs4_dentry_ino(dentry->d_parent);
+        if (p_ino && dentry->d_parent != dentry)
+                atomic_inc(&p_ino->count);
         ino->inode = inode;
         dir->i_nlink++;
         dir->i_mtime = CURRENT_TIME;