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[PATCH] lock exclusively in collect_mounts() and drop_collected_mounts()

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Taking namespace_sem shared there isn't worth the trouble, especially with
vfsmount ID allocation about to be added.  That way we know that umount_tree(),
copy_tree() and clone_mnt() are _always_ serialized by namespace_sem.
umount_tree() still needs vfsmount_lock (it manipulates hash chains, among
other things), but that's a separate story.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2008-03-22 16:19:49 -04:00
parent 6d59e7f582
commit 1a60a28077
1 changed files with 4 additions and 4 deletions
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8
fs/namespace.c
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@ -1091,20 +1091,20 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
struct vfsmount *collect_mounts(struct vfsmount *mnt, struct dentry *dentry) struct vfsmount *collect_mounts(struct vfsmount *mnt, struct dentry *dentry)
{ {
struct vfsmount *tree; struct vfsmount *tree;
down_read(&namespace_sem); down_write(&namespace_sem);
tree = copy_tree(mnt, dentry, CL_COPY_ALL | CL_PRIVATE); tree = copy_tree(mnt, dentry, CL_COPY_ALL | CL_PRIVATE);
up_read(&namespace_sem); up_write(&namespace_sem);
return tree; return tree;
} }
void drop_collected_mounts(struct vfsmount *mnt) void drop_collected_mounts(struct vfsmount *mnt)
{ {
LIST_HEAD(umount_list); LIST_HEAD(umount_list);
down_read(&namespace_sem); down_write(&namespace_sem);
spin_lock(&vfsmount_lock); spin_lock(&vfsmount_lock);
umount_tree(mnt, 0, &umount_list); umount_tree(mnt, 0, &umount_list);
spin_unlock(&vfsmount_lock); spin_unlock(&vfsmount_lock);
up_read(&namespace_sem); up_write(&namespace_sem);
release_mounts(&umount_list); release_mounts(&umount_list);
} }