diff options
| -rw-r--r-- | fs/namespace.c | 53 |
1 files changed, 30 insertions, 23 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index fa93d54d21e8..ed0708f2415f 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1121,11 +1121,21 @@ EXPORT_SYMBOL(may_umount); static LIST_HEAD(unmounted); /* protected by namespace_sem */ -static void release_mounts(struct list_head *head) +static void namespace_unlock(void) { struct mount *mnt; - while (!list_empty(head)) { - mnt = list_first_entry(head, struct mount, mnt_hash); + LIST_HEAD(head); + + if (likely(list_empty(&unmounted))) { + up_write(&namespace_sem); + return; + } + + list_splice_init(&unmounted, &head); + up_write(&namespace_sem); + + while (!list_empty(&head)) { + mnt = list_first_entry(&head, struct mount, mnt_hash); list_del_init(&mnt->mnt_hash); if (mnt_has_parent(mnt)) { struct dentry *dentry; @@ -1145,12 +1155,9 @@ static void release_mounts(struct list_head *head) } } -static void namespace_unlock(void) +static inline void namespace_lock(void) { - LIST_HEAD(head); - list_splice_init(&unmounted, &head); - up_write(&namespace_sem); - release_mounts(&head); + down_write(&namespace_sem); } /* @@ -1256,7 +1263,7 @@ static int do_umount(struct mount *mnt, int flags) return retval; } - down_write(&namespace_sem); + namespace_lock(); br_write_lock(&vfsmount_lock); event++; @@ -1412,7 +1419,7 @@ out: struct vfsmount *collect_mounts(struct path *path) { struct mount *tree; - down_write(&namespace_sem); + namespace_lock(); tree = copy_tree(real_mount(path->mnt), path->dentry, CL_COPY_ALL | CL_PRIVATE); namespace_unlock(); @@ -1423,7 +1430,7 @@ struct vfsmount *collect_mounts(struct path *path) void drop_collected_mounts(struct vfsmount *mnt) { - down_write(&namespace_sem); + namespace_lock(); br_write_lock(&vfsmount_lock); umount_tree(real_mount(mnt), 0); br_write_unlock(&vfsmount_lock); @@ -1593,18 +1600,18 @@ retry: mutex_unlock(&dentry->d_inode->i_mutex); return ERR_PTR(-ENOENT); } - down_write(&namespace_sem); + namespace_lock(); mnt = lookup_mnt(path); if (likely(!mnt)) { struct mountpoint *mp = new_mountpoint(dentry); if (IS_ERR(mp)) { - up_write(&namespace_sem); + namespace_unlock(); mutex_unlock(&dentry->d_inode->i_mutex); return mp; } return mp; } - up_write(&namespace_sem); + namespace_unlock(); mutex_unlock(&path->dentry->d_inode->i_mutex); path_put(path); path->mnt = mnt; @@ -1667,7 +1674,7 @@ static int do_change_type(struct path *path, int flag) if (!type) return -EINVAL; - down_write(&namespace_sem); + namespace_lock(); if (type == MS_SHARED) { err = invent_group_ids(mnt, recurse); if (err) @@ -1680,7 +1687,7 @@ static int do_change_type(struct path *path, int flag) br_write_unlock(&vfsmount_lock); out_unlock: - up_write(&namespace_sem); + namespace_unlock(); return err; } @@ -2016,11 +2023,11 @@ int finish_automount(struct vfsmount *m, struct path *path) fail: /* remove m from any expiration list it may be on */ if (!list_empty(&mnt->mnt_expire)) { - down_write(&namespace_sem); + namespace_lock(); br_write_lock(&vfsmount_lock); list_del_init(&mnt->mnt_expire); br_write_unlock(&vfsmount_lock); - up_write(&namespace_sem); + namespace_unlock(); } mntput(m); mntput(m); @@ -2034,13 +2041,13 @@ fail: */ void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list) { - down_write(&namespace_sem); + namespace_lock(); br_write_lock(&vfsmount_lock); list_add_tail(&real_mount(mnt)->mnt_expire, expiry_list); br_write_unlock(&vfsmount_lock); - up_write(&namespace_sem); + namespace_unlock(); } EXPORT_SYMBOL(mnt_set_expiry); @@ -2057,7 +2064,7 @@ void mark_mounts_for_expiry(struct list_head *mounts) if (list_empty(mounts)) return; - down_write(&namespace_sem); + namespace_lock(); br_write_lock(&vfsmount_lock); /* extract from the expiration list every vfsmount that matches the @@ -2373,7 +2380,7 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns, if (IS_ERR(new_ns)) return new_ns; - down_write(&namespace_sem); + namespace_lock(); /* First pass: copy the tree topology */ copy_flags = CL_COPY_ALL | CL_EXPIRE; if (user_ns != mnt_ns->user_ns) @@ -2733,7 +2740,7 @@ void put_mnt_ns(struct mnt_namespace *ns) { if (!atomic_dec_and_test(&ns->count)) return; - down_write(&namespace_sem); + namespace_lock(); br_write_lock(&vfsmount_lock); umount_tree(ns->root, 0); br_write_unlock(&vfsmount_lock); |