3 files changed, 44 insertions, 39 deletions

diff --git a/fs/dquot.c b/fs/dquot.c
index afa06a893468..05b60283c9c2 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -1321,13 +1321,11 @@ int vfs_quota_off(struct super_block *sb, int type)
         int cnt;
         struct quota_info *dqopt = sb_dqopt(sb);
         struct inode *toputinode[MAXQUOTAS];
-        struct vfsmount *toputmnt[MAXQUOTAS];
 
         /* We need to serialize quota_off() for device */
         down(&dqopt->dqonoff_sem);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                 toputinode[cnt] = NULL;
-                toputmnt[cnt] = NULL;
                 if (type != -1 && cnt != type)
                         continue;
                 if (!sb_has_quota_enabled(sb, cnt))
@@ -1348,9 +1346,7 @@ int vfs_quota_off(struct super_block *sb, int type)
                 put_quota_format(dqopt->info[cnt].dqi_format);
 
                 toputinode[cnt] = dqopt->files[cnt];
-                toputmnt[cnt] = dqopt->mnt[cnt];
                 dqopt->files[cnt] = NULL;
-                dqopt->mnt[cnt] = NULL;
                 dqopt->info[cnt].dqi_flags = 0;
                 dqopt->info[cnt].dqi_igrace = 0;
                 dqopt->info[cnt].dqi_bgrace = 0;
@@ -1358,10 +1354,7 @@ int vfs_quota_off(struct super_block *sb, int type)
         }
         up(&dqopt->dqonoff_sem);
         /* Sync the superblock so that buffers with quota data are written to
-         * disk (and so userspace sees correct data afterwards).
-         * The reference to vfsmnt we are still holding protects us from
-         * umount (we don't have it only when quotas are turned on/off for
-         * journal replay but in that case we are guarded by the fs anyway). */
+         * disk (and so userspace sees correct data afterwards). */
         if (sb->s_op->sync_fs)
                 sb->s_op->sync_fs(sb, 1);
         sync_blockdev(sb->s_bdev);
@@ -1385,10 +1378,6 @@ int vfs_quota_off(struct super_block *sb, int type)
                                 iput(toputinode[cnt]);
                         }
                         up(&dqopt->dqonoff_sem);
-                        /* We don't hold the reference when we turned on quotas
-                         * just for the journal replay... */
-                        if (toputmnt[cnt])
-                                mntput(toputmnt[cnt]);
                 }
         if (sb->s_bdev)
                 invalidate_bdev(sb->s_bdev, 0);
@@ -1503,11 +1492,8 @@ int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
         /* Quota file not on the same filesystem? */
         if (nd.mnt->mnt_sb != sb)
                 error = -EXDEV;
-        else {
+        else
                 error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
-                if (!error)
-                        sb_dqopt(sb)->mnt[type] = mntget(nd.mnt);
-        }
 out_path:
         path_release(&nd);
         return error;
diff --git a/fs/namespace.c b/fs/namespace.c
index 2fa9fdf7d6f5..1d83302f30c3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -172,7 +172,7 @@ clone_mnt(struct vfsmount *old, struct dentry *root)
         return mnt;
 }
 
-void __mntput(struct vfsmount *mnt)
+static inline void __mntput(struct vfsmount *mnt)
 {
         struct super_block *sb = mnt->mnt_sb;
         dput(mnt->mnt_root);
@@ -180,7 +180,46 @@ void __mntput(struct vfsmount *mnt)
         deactivate_super(sb);
 }
 
-EXPORT_SYMBOL(__mntput);
+void mntput_no_expire(struct vfsmount *mnt)
+{
+repeat:
+        if (atomic_dec_and_lock(&mnt->mnt_count, &vfsmount_lock)) {
+                if (likely(!mnt->mnt_pinned)) {
+                        spin_unlock(&vfsmount_lock);
+                        __mntput(mnt);
+                        return;
+                }
+                atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count);
+                mnt->mnt_pinned = 0;
+                spin_unlock(&vfsmount_lock);
+                acct_auto_close_mnt(mnt);
+                security_sb_umount_close(mnt);
+                goto repeat;
+        }
+}
+
+EXPORT_SYMBOL(mntput_no_expire);
+
+void mnt_pin(struct vfsmount *mnt)
+{
+        spin_lock(&vfsmount_lock);
+        mnt->mnt_pinned++;
+        spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL(mnt_pin);
+
+void mnt_unpin(struct vfsmount *mnt)
+{
+        spin_lock(&vfsmount_lock);
+        if (mnt->mnt_pinned) {
+                atomic_inc(&mnt->mnt_count);
+                mnt->mnt_pinned--;
+        }
+        spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL(mnt_unpin);
 
 /* iterator */
 static void *m_start(struct seq_file *m, loff_t *pos)
@@ -435,16 +474,6 @@ static int do_umount(struct vfsmount *mnt, int flags)
         down_write(&current->namespace->sem);
         spin_lock(&vfsmount_lock);
 
-        if (atomic_read(&sb->s_active) == 1) {
-                /* last instance - try to be smart */
-                spin_unlock(&vfsmount_lock);
-                lock_kernel();
-                DQUOT_OFF(sb);
-                acct_auto_close(sb);
-                unlock_kernel();
-                security_sb_umount_close(mnt);
-                spin_lock(&vfsmount_lock);
-        }
         retval = -EBUSY;
         if (atomic_read(&mnt->mnt_count) == 2 || flags & MNT_DETACH) {
                 if (!list_empty(&mnt->mnt_list))
@@ -850,17 +879,6 @@ static void expire_mount(struct vfsmount *mnt, struct list_head *mounts)
                 detach_mnt(mnt, &old_nd);
                 spin_unlock(&vfsmount_lock);
                 path_release(&old_nd);
-
-                /*
-                 * Now lay it to rest if this was the last ref on the superblock
-                 */
-                if (atomic_read(&mnt->mnt_sb->s_active) == 1) {
-                        /* last instance - try to be smart */
-                        lock_kernel();
-                        DQUOT_OFF(mnt->mnt_sb);
-                        acct_auto_close(mnt->mnt_sb);
-                        unlock_kernel();
-                }
                 mntput(mnt);
         } else {
                 /*
diff --git a/fs/super.c b/fs/super.c
index eed6c3132905..6689dded3c84 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -171,6 +171,7 @@ void deactivate_super(struct super_block *s)
         if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
                 s->s_count -= S_BIAS-1;
                 spin_unlock(&sb_lock);
+                DQUOT_OFF(s);
                 down_write(&s->s_umount);
                 fs->kill_sb(s);
                 put_filesystem(fs);