3 files changed, 87 insertions, 69 deletions

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 3912dcf047e5..9d2ae9b30d9f 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -254,6 +254,17 @@ static inline int simple_positive(struct dentry *dentry)
         return dentry->d_inode && !d_unhashed(dentry);
 }
 
+static inline void __autofs4_add_expiring(struct dentry *dentry)
+{
+        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+        struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        if (ino) {
+                if (list_empty(&ino->expiring))
+                        list_add(&ino->expiring, &sbi->expiring_list);
+        }
+        return;
+}
+
 static inline void autofs4_add_expiring(struct dentry *dentry)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index ee6402050f13..968c1434af62 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -91,24 +91,64 @@ done:
 }
 
 /*
- * Calculate next entry in top down tree traversal.
- * From next_mnt in namespace.c - elegant.
+ * Calculate and dget next entry in top down tree traversal.
  */
-static struct dentry *next_dentry(struct dentry *p, struct dentry *root)
+static struct dentry *get_next_positive_dentry(struct dentry *prev,
+                                                struct dentry *root)
 {
-        struct list_head *next = p->d_subdirs.next;
+        struct list_head *next;
+        struct dentry *p, *ret;
+
+        if (prev == NULL)
+                return dget(prev);
 
+        spin_lock(&dcache_lock);
+relock:
+        p = prev;
+        spin_lock(&p->d_lock);
+again:
+        next = p->d_subdirs.next;
         if (next == &p->d_subdirs) {
                 while (1) {
-                        if (p == root)
+                        struct dentry *parent;
+
+                        if (p == root) {
+                                spin_unlock(&p->d_lock);
+                                spin_unlock(&dcache_lock);
+                                dput(prev);
                                 return NULL;
+                        }
+
+                        parent = p->d_parent;
+                        if (!spin_trylock(&parent->d_lock)) {
+                                spin_unlock(&p->d_lock);
+                                cpu_relax();
+                                goto relock;
+                        }
+                        spin_unlock(&p->d_lock);
                         next = p->d_u.d_child.next;
-                        if (next != &p->d_parent->d_subdirs)
+                        p = parent;
+                        if (next != &parent->d_subdirs)
                                 break;
-                        p = p->d_parent;
                 }
         }
-        return list_entry(next, struct dentry, d_u.d_child);
+        ret = list_entry(next, struct dentry, d_u.d_child);
+
+        spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
+        /* Negative dentry - try next */
+        if (!simple_positive(ret)) {
+                spin_unlock(&ret->d_lock);
+                p = ret;
+                goto again;
+        }
+        dget_dlock(ret);
+        spin_unlock(&ret->d_lock);
+        spin_unlock(&p->d_lock);
+        spin_unlock(&dcache_lock);
+
+        dput(prev);
+
+        return ret;
 }
 
 /*
@@ -158,22 +198,11 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
         if (!simple_positive(top))
                 return 1;
 
-        spin_lock(&dcache_lock);
-        for (p = top; p; p = next_dentry(p, top)) {
-                spin_lock(&p->d_lock);
-                /* Negative dentry - give up */
-                if (!simple_positive(p)) {
-                        spin_unlock(&p->d_lock);
-                        continue;
-                }
-
+        p = NULL;
+        while ((p = get_next_positive_dentry(p, top))) {
                 DPRINTK("dentry %p %.*s",
                         p, (int) p->d_name.len, p->d_name.name);
 
-                p = dget_dlock(p);
-                spin_unlock(&p->d_lock);
-                spin_unlock(&dcache_lock);
-
                 /*
                  * Is someone visiting anywhere in the subtree ?
                  * If there's no mount we need to check the usage
@@ -208,10 +237,7 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
                                 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))
@@ -230,36 +256,21 @@ static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
         DPRINTK("parent %p %.*s",
                 parent, (int)parent->d_name.len, parent->d_name.name);
 
-        spin_lock(&dcache_lock);
-        for (p = parent; p; p = next_dentry(p, parent)) {
-                spin_lock(&p->d_lock);
-                /* Negative dentry - give up */
-                if (!simple_positive(p)) {
-                        spin_unlock(&p->d_lock);
-                        continue;
-                }
-
+        p = NULL;
+        while ((p = get_next_positive_dentry(p, parent))) {
                 DPRINTK("dentry %p %.*s",
                         p, (int) p->d_name.len, p->d_name.name);
 
-                p = dget_dlock(p);
-                spin_unlock(&p->d_lock);
-                spin_unlock(&dcache_lock);
-
                 if (d_mountpoint(p)) {
                         /* Can we umount this guy */
                         if (autofs4_mount_busy(mnt, p))
-                                goto cont;
+                                continue;
 
                         /* Can we expire this guy */
                         if (autofs4_can_expire(p, timeout, do_now))
                                 return p;
                 }
-cont:
-                dput(p);
-                spin_lock(&dcache_lock);
         }
-        spin_unlock(&dcache_lock);
         return NULL;
 }
 
@@ -310,8 +321,8 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
 {
         unsigned long timeout;
         struct dentry *root = sb->s_root;
+        struct dentry *dentry;
         struct dentry *expired = NULL;
-        struct list_head *next;
         int do_now = how & AUTOFS_EXP_IMMEDIATE;
         int exp_leaves = how & AUTOFS_EXP_LEAVES;
         struct autofs_info *ino;
@@ -323,26 +334,8 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
         now = jiffies;
         timeout = sbi->exp_timeout;
 
-        spin_lock(&dcache_lock);
-        next = root->d_subdirs.next;
-
-        /* On exit from the loop expire is set to a dgot dentry
-         * to expire or it's NULL */
-        while ( next != &root->d_subdirs ) {
-                struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
-
-                /* Negative dentry - give up */
-                spin_lock(&dentry->d_lock);
-                if (!simple_positive(dentry)) {
-                        next = next->next;
-                        spin_unlock(&dentry->d_lock);
-                        continue;
-                }
-
-                dentry = dget_dlock(dentry);
-                spin_unlock(&dentry->d_lock);
-                spin_unlock(&dcache_lock);
-
+        dentry = NULL;
+        while ((dentry = get_next_positive_dentry(dentry, root))) {
                 spin_lock(&sbi->fs_lock);
                 ino = autofs4_dentry_ino(dentry);
 
@@ -405,11 +398,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
                 }
 next:
                 spin_unlock(&sbi->fs_lock);
-                dput(dentry);
-                spin_lock(&dcache_lock);
-                next = next->next;
         }
-        spin_unlock(&dcache_lock);
         return NULL;
 
 found:
@@ -420,7 +409,11 @@ found:
         init_completion(&ino->expire_complete);
         spin_unlock(&sbi->fs_lock);
         spin_lock(&dcache_lock);
+        spin_lock(&expired->d_parent->d_lock);
+        spin_lock_nested(&expired->d_lock, DENTRY_D_LOCK_NESTED);
         list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
+        spin_unlock(&expired->d_lock);
+        spin_unlock(&expired->d_parent->d_lock);
         spin_unlock(&dcache_lock);
         return expired;
 }
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 7922509b5b2b..7a9ed6b88291 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -143,10 +143,13 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
          * it.
          */
         spin_lock(&dcache_lock);
+        spin_lock(&dentry->d_lock);
         if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
+                spin_unlock(&dentry->d_lock);
                 spin_unlock(&dcache_lock);
                 return -ENOENT;
         }
+        spin_unlock(&dentry->d_lock);
         spin_unlock(&dcache_lock);
 
 out:
@@ -253,7 +256,9 @@ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
         lookup_type = autofs4_need_mount(nd->flags);
         spin_lock(&sbi->fs_lock);
         spin_lock(&dcache_lock);
+        spin_lock(&dentry->d_lock);
         if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) {
+                spin_unlock(&dentry->d_lock);
                 spin_unlock(&dcache_lock);
                 spin_unlock(&sbi->fs_lock);
                 goto follow;
@@ -266,6 +271,7 @@ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
          */
         if (ino->flags & AUTOFS_INF_PENDING ||
             (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) {
+                spin_unlock(&dentry->d_lock);
                 spin_unlock(&dcache_lock);
                 spin_unlock(&sbi->fs_lock);
 
@@ -275,6 +281,7 @@ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
 
                 goto follow;
         }
+        spin_unlock(&dentry->d_lock);
         spin_unlock(&dcache_lock);
         spin_unlock(&sbi->fs_lock);
 follow:
@@ -347,10 +354,12 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
 
         /* Check for a non-mountpoint directory with no contents */
         spin_lock(&dcache_lock);
+        spin_lock(&dentry->d_lock);
         if (S_ISDIR(dentry->d_inode->i_mode) &&
             !d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
                 DPRINTK("dentry=%p %.*s, emptydir",
                          dentry, dentry->d_name.len, dentry->d_name.name);
+                spin_unlock(&dentry->d_lock);
                 spin_unlock(&dcache_lock);
 
                 /* The daemon never causes a mount to trigger */
@@ -367,6 +376,7 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
 
                 return status;
         }
+        spin_unlock(&dentry->d_lock);
         spin_unlock(&dcache_lock);
 
         return 1;
@@ -776,12 +786,16 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
                 return -EACCES;
 
         spin_lock(&dcache_lock);
+        spin_lock(&sbi->lookup_lock);
+        spin_lock(&dentry->d_lock);
         if (!list_empty(&dentry->d_subdirs)) {
+                spin_unlock(&dentry->d_lock);
+                spin_unlock(&sbi->lookup_lock);
                 spin_unlock(&dcache_lock);
                 return -ENOTEMPTY;
         }
-        autofs4_add_expiring(dentry);
-        spin_lock(&dentry->d_lock);
+        __autofs4_add_expiring(dentry);
+        spin_unlock(&sbi->lookup_lock);
         __d_drop(dentry);
         spin_unlock(&dentry->d_lock);
         spin_unlock(&dcache_lock);