1 files changed, 77 insertions, 14 deletions

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 894fee54d4d8..cdabb796ff01 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -259,13 +259,15 @@ static struct dentry *autofs4_expire_direct(struct super_block *sb,
         now = jiffies;
         timeout = sbi->exp_timeout;
 
-        /* Lock the tree as we must expire as a whole */
         spin_lock(&sbi->fs_lock);
         if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
                 struct autofs_info *ino = autofs4_dentry_ino(root);
-
-                /* Set this flag early to catch sys_chdir and the like */
+                if (d_mountpoint(root)) {
+                        ino->flags |= AUTOFS_INF_MOUNTPOINT;
+                        root->d_mounted--;
+                }
                 ino->flags |= AUTOFS_INF_EXPIRING;
+                init_completion(&ino->expire_complete);
                 spin_unlock(&sbi->fs_lock);
                 return root;
         }
@@ -292,6 +294,8 @@ static struct dentry *autofs4_expire_indirect(struct super_block *sb,
         struct list_head *next;
         int do_now = how & AUTOFS_EXP_IMMEDIATE;
         int exp_leaves = how & AUTOFS_EXP_LEAVES;
+        struct autofs_info *ino;
+        unsigned int ino_count;
 
         if (!root)
                 return NULL;
@@ -316,6 +320,9 @@ static struct dentry *autofs4_expire_indirect(struct super_block *sb,
                 dentry = dget(dentry);
                 spin_unlock(&dcache_lock);
 
+                spin_lock(&sbi->fs_lock);
+                ino = autofs4_dentry_ino(dentry);
+
                 /*
                  * Case 1: (i) indirect mount or top level pseudo direct mount
                  *         (autofs-4.1).
@@ -326,6 +333,11 @@ static struct dentry *autofs4_expire_indirect(struct super_block *sb,
                         DPRINTK("checking mountpoint %p %.*s",
                                 dentry, (int)dentry->d_name.len, dentry->d_name.name);
 
+                        /* Path walk currently on this dentry? */
+                        ino_count = atomic_read(&ino->count) + 2;
+                        if (atomic_read(&dentry->d_count) > ino_count)
+                                goto next;
+
                         /* Can we umount this guy */
                         if (autofs4_mount_busy(mnt, dentry))
                                 goto next;
@@ -343,23 +355,25 @@ static struct dentry *autofs4_expire_indirect(struct super_block *sb,
 
                 /* Case 2: tree mount, expire iff entire tree is not busy */
                 if (!exp_leaves) {
-                        /* Lock the tree as we must expire as a whole */
-                        spin_lock(&sbi->fs_lock);
-                        if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
-                                struct autofs_info *inf = autofs4_dentry_ino(dentry);
+                        /* Path walk currently on this dentry? */
+                        ino_count = atomic_read(&ino->count) + 1;
+                        if (atomic_read(&dentry->d_count) > ino_count)
+                                goto next;
 
-                                /* Set this flag early to catch sys_chdir and the like */
-                                inf->flags |= AUTOFS_INF_EXPIRING;
-                                spin_unlock(&sbi->fs_lock);
+                        if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
                                 expired = dentry;
                                 goto found;
                         }
-                        spin_unlock(&sbi->fs_lock);
                 /*
                  * Case 3: pseudo direct mount, expire individual leaves
                  *         (autofs-4.1).
                  */
                 } else {
+                        /* Path walk currently on this dentry? */
+                        ino_count = atomic_read(&ino->count) + 1;
+                        if (atomic_read(&dentry->d_count) > ino_count)
+                                goto next;
+
                         expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
                         if (expired) {
                                 dput(dentry);
@@ -367,6 +381,7 @@ static struct dentry *autofs4_expire_indirect(struct super_block *sb,
                         }
                 }
 next:
+                spin_unlock(&sbi->fs_lock);
                 dput(dentry);
                 spin_lock(&dcache_lock);
                 next = next->next;
@@ -377,12 +392,45 @@ next:
 found:
         DPRINTK("returning %p %.*s",
                 expired, (int)expired->d_name.len, expired->d_name.name);
+        ino = autofs4_dentry_ino(expired);
+        ino->flags |= AUTOFS_INF_EXPIRING;
+        init_completion(&ino->expire_complete);
+        spin_unlock(&sbi->fs_lock);
         spin_lock(&dcache_lock);
         list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
         spin_unlock(&dcache_lock);
         return expired;
 }
 
+int autofs4_expire_wait(struct dentry *dentry)
+{
+        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+        struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        int status;
+
+        /* Block on any pending expire */
+        spin_lock(&sbi->fs_lock);
+        if (ino->flags & AUTOFS_INF_EXPIRING) {
+                spin_unlock(&sbi->fs_lock);
+
+                DPRINTK("waiting for expire %p name=%.*s",
+                         dentry, dentry->d_name.len, dentry->d_name.name);
+
+                status = autofs4_wait(sbi, dentry, NFY_NONE);
+                wait_for_completion(&ino->expire_complete);
+
+                DPRINTK("expire done status=%d", status);
+
+                if (d_unhashed(dentry))
+                        return -EAGAIN;
+
+                return status;
+        }
+        spin_unlock(&sbi->fs_lock);
+
+        return 0;
+}
+
 /* Perform an expiry operation */
 int autofs4_expire_run(struct super_block *sb,
                       struct vfsmount *mnt,
@@ -390,7 +438,9 @@ int autofs4_expire_run(struct super_block *sb,
                       struct autofs_packet_expire __user *pkt_p)
 {
         struct autofs_packet_expire pkt;
+        struct autofs_info *ino;
         struct dentry *dentry;
+        int ret = 0;
 
         memset(&pkt,0,sizeof pkt);
 
@@ -406,9 +456,15 @@ int autofs4_expire_run(struct super_block *sb,
         dput(dentry);
 
         if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) )
-                return -EFAULT;
+                ret = -EFAULT;
 
-        return 0;
+        spin_lock(&sbi->fs_lock);
+        ino = autofs4_dentry_ino(dentry);
+        ino->flags &= ~AUTOFS_INF_EXPIRING;
+        complete_all(&ino->expire_complete);
+        spin_unlock(&sbi->fs_lock);
+
+        return ret;
 }
 
 /* Call repeatedly until it returns -EAGAIN, meaning there's nothing
@@ -433,9 +489,16 @@ int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 
                 /* This is synchronous because it makes the daemon a
                    little easier */
-                ino->flags |= AUTOFS_INF_EXPIRING;
                 ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
+
+                spin_lock(&sbi->fs_lock);
+                if (ino->flags & AUTOFS_INF_MOUNTPOINT) {
+                        sb->s_root->d_mounted++;
+                        ino->flags &= ~AUTOFS_INF_MOUNTPOINT;
+                }
                 ino->flags &= ~AUTOFS_INF_EXPIRING;
+                complete_all(&ino->expire_complete);
+                spin_unlock(&sbi->fs_lock);
                 dput(dentry);
         }