summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--fs/mount.h1
-rw-r--r--fs/namespace.c35
-rw-r--r--include/linux/mount.h4
-rw-r--r--kernel/acct.c24
4 files changed, 30 insertions, 34 deletions
diff --git a/fs/mount.h b/fs/mount.h
index 0a2d145..6740a62 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -55,7 +55,6 @@ struct mount {
int mnt_id; /* mount identifier */
int mnt_group_id; /* peer group identifier */
int mnt_expiry_mark; /* true if marked for expiry */
- int mnt_pinned;
struct hlist_head mnt_pins;
struct path mnt_ex_mountpoint;
};
diff --git a/fs/namespace.c b/fs/namespace.c
index 0e4ce51..65af9d0 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -937,7 +937,6 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
static void mntput_no_expire(struct mount *mnt)
{
-put_again:
rcu_read_lock();
mnt_add_count(mnt, -1);
if (likely(mnt->mnt_ns)) { /* shouldn't be the last one */
@@ -950,14 +949,6 @@ put_again:
unlock_mount_hash();
return;
}
- if (unlikely(mnt->mnt_pinned)) {
- mnt_add_count(mnt, mnt->mnt_pinned + 1);
- mnt->mnt_pinned = 0;
- rcu_read_unlock();
- unlock_mount_hash();
- mnt_pin_kill(mnt);
- goto put_again;
- }
if (unlikely(mnt->mnt.mnt_flags & MNT_DOOMED)) {
rcu_read_unlock();
unlock_mount_hash();
@@ -980,6 +971,8 @@ put_again:
* so mnt_get_writers() below is safe.
*/
WARN_ON(mnt_get_writers(mnt));
+ if (unlikely(mnt->mnt_pins.first))
+ mnt_pin_kill(mnt);
fsnotify_vfsmount_delete(&mnt->mnt);
dput(mnt->mnt.mnt_root);
deactivate_super(mnt->mnt.mnt_sb);
@@ -1007,25 +1000,15 @@ struct vfsmount *mntget(struct vfsmount *mnt)
}
EXPORT_SYMBOL(mntget);
-void mnt_pin(struct vfsmount *mnt)
+struct vfsmount *mnt_clone_internal(struct path *path)
{
- lock_mount_hash();
- real_mount(mnt)->mnt_pinned++;
- unlock_mount_hash();
-}
-EXPORT_SYMBOL(mnt_pin);
-
-void mnt_unpin(struct vfsmount *m)
-{
- struct mount *mnt = real_mount(m);
- lock_mount_hash();
- if (mnt->mnt_pinned) {
- mnt_add_count(mnt, 1);
- mnt->mnt_pinned--;
- }
- unlock_mount_hash();
+ struct mount *p;
+ p = clone_mnt(real_mount(path->mnt), path->dentry, CL_PRIVATE);
+ if (IS_ERR(p))
+ return ERR_CAST(p);
+ p->mnt.mnt_flags |= MNT_INTERNAL;
+ return &p->mnt;
}
-EXPORT_SYMBOL(mnt_unpin);
static inline void mangle(struct seq_file *m, const char *s)
{
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 839bac2..864b120 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -62,6 +62,7 @@ struct vfsmount {
};
struct file; /* forward dec */
+struct path;
extern int mnt_want_write(struct vfsmount *mnt);
extern int mnt_want_write_file(struct file *file);
@@ -70,8 +71,7 @@ extern void mnt_drop_write(struct vfsmount *mnt);
extern void mnt_drop_write_file(struct file *file);
extern void mntput(struct vfsmount *mnt);
extern struct vfsmount *mntget(struct vfsmount *mnt);
-extern void mnt_pin(struct vfsmount *mnt);
-extern void mnt_unpin(struct vfsmount *mnt);
+extern struct vfsmount *mnt_clone_internal(struct path *path);
extern int __mnt_is_readonly(struct vfsmount *mnt);
struct file_system_type;
diff --git a/kernel/acct.c b/kernel/acct.c
index a7993a6..2e6cf818 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -154,7 +154,6 @@ static void close_work(struct work_struct *work)
{
struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work);
struct file *file = acct->file;
- mnt_unpin(file->f_path.mnt);
if (file->f_op->flush)
file->f_op->flush(file, NULL);
__fput_sync(file);
@@ -196,9 +195,10 @@ static void acct_pin_kill(struct fs_pin *pin)
static int acct_on(struct filename *pathname)
{
struct file *file;
- struct vfsmount *mnt;
+ struct vfsmount *mnt, *internal;
struct pid_namespace *ns = task_active_pid_ns(current);
struct bsd_acct_struct *acct, *old;
+ int err;
acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
if (!acct)
@@ -222,6 +222,21 @@ static int acct_on(struct filename *pathname)
filp_close(file, NULL);
return -EIO;
}
+ internal = mnt_clone_internal(&file->f_path);
+ if (IS_ERR(internal)) {
+ kfree(acct);
+ filp_close(file, NULL);
+ return PTR_ERR(internal);
+ }
+ err = mnt_want_write(internal);
+ if (err) {
+ mntput(internal);
+ kfree(acct);
+ filp_close(file, NULL);
+ return err;
+ }
+ mnt = file->f_path.mnt;
+ file->f_path.mnt = internal;
atomic_long_set(&acct->pin.count, 1);
acct->pin.kill = acct_pin_kill;
@@ -229,8 +244,6 @@ static int acct_on(struct filename *pathname)
acct->needcheck = jiffies;
acct->ns = ns;
mutex_init(&acct->lock);
- mnt = file->f_path.mnt;
- mnt_pin(mnt);
mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */
pin_insert(&acct->pin, mnt);
@@ -240,7 +253,8 @@ static int acct_on(struct filename *pathname)
else
ns->bacct = acct;
mutex_unlock(&acct->lock);
- mntput(mnt); /* it's pinned, now give up active reference */
+ mnt_drop_write(mnt);
+ mntput(mnt);
return 0;
}
OpenPOWER on IntegriCloud