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-rw-r--r--fs/namespace.c64
1 files changed, 41 insertions, 23 deletions
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 {
/*