audit_tree: Remove mark->lock locking
Currently, audit_tree code uses mark->lock to protect against detaching of mark from an inode. In most places it however also uses mark->group->mark_mutex (as we need to atomically replace attached marks) and this provides protection against mark detaching as well. So just remove protection with mark->lock from audit tree code and replace it with mark->group->mark_mutex protection in all the places. It simplifies the code and gets rid of some ugly catches like calling fsnotify_add_mark_locked() with mark->lock held (which cannot sleep only because we hold a reference to another mark attached to the same inode). Reviewed-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Paul Moore <paul@paul-moore.com>
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@ -193,7 +193,7 @@ static inline struct list_head *chunk_hash(unsigned long key)
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return chunk_hash_heads + n % HASH_SIZE;
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}
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/* hash_lock & entry->lock is held by caller */
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/* hash_lock & entry->group->mark_mutex is held by caller */
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static void insert_hash(struct audit_chunk *chunk)
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{
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unsigned long key = chunk_to_key(chunk);
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@ -256,13 +256,11 @@ static void untag_chunk(struct node *p)
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new = alloc_chunk(size);
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mutex_lock(&entry->group->mark_mutex);
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spin_lock(&entry->lock);
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/*
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* mark_mutex protects mark from getting detached and thus also from
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* mark->connector->obj getting NULL.
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*/
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if (chunk->dead || !(entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
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spin_unlock(&entry->lock);
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mutex_unlock(&entry->group->mark_mutex);
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if (new)
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fsnotify_put_mark(&new->mark);
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@ -280,7 +278,6 @@ static void untag_chunk(struct node *p)
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list_del_init(&p->list);
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list_del_rcu(&chunk->hash);
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spin_unlock(&hash_lock);
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spin_unlock(&entry->lock);
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mutex_unlock(&entry->group->mark_mutex);
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fsnotify_destroy_mark(entry, audit_tree_group);
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goto out;
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@ -323,7 +320,6 @@ static void untag_chunk(struct node *p)
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list_for_each_entry(owner, &new->trees, same_root)
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owner->root = new;
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spin_unlock(&hash_lock);
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spin_unlock(&entry->lock);
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mutex_unlock(&entry->group->mark_mutex);
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fsnotify_destroy_mark(entry, audit_tree_group);
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fsnotify_put_mark(&new->mark); /* drop initial reference */
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@ -340,7 +336,6 @@ Fallback:
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p->owner = NULL;
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put_tree(owner);
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spin_unlock(&hash_lock);
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spin_unlock(&entry->lock);
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mutex_unlock(&entry->group->mark_mutex);
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out:
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fsnotify_put_mark(entry);
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@ -360,12 +355,12 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
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return -ENOSPC;
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}
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spin_lock(&entry->lock);
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mutex_lock(&entry->group->mark_mutex);
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spin_lock(&hash_lock);
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if (tree->goner) {
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spin_unlock(&hash_lock);
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chunk->dead = 1;
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spin_unlock(&entry->lock);
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mutex_unlock(&entry->group->mark_mutex);
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fsnotify_destroy_mark(entry, audit_tree_group);
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fsnotify_put_mark(entry);
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return 0;
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@ -380,7 +375,7 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
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}
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insert_hash(chunk);
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spin_unlock(&hash_lock);
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spin_unlock(&entry->lock);
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mutex_unlock(&entry->group->mark_mutex);
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fsnotify_put_mark(entry); /* drop initial reference */
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return 0;
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}
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@ -421,14 +416,12 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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chunk_entry = &chunk->mark;
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mutex_lock(&old_entry->group->mark_mutex);
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spin_lock(&old_entry->lock);
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/*
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* mark_mutex protects mark from getting detached and thus also from
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* mark->connector->obj getting NULL.
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*/
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if (!(old_entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
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/* old_entry is being shot, lets just lie */
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spin_unlock(&old_entry->lock);
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mutex_unlock(&old_entry->group->mark_mutex);
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fsnotify_put_mark(old_entry);
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fsnotify_put_mark(&chunk->mark);
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@ -437,23 +430,16 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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if (fsnotify_add_mark_locked(chunk_entry, old_entry->connector->obj,
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FSNOTIFY_OBJ_TYPE_INODE, 1)) {
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spin_unlock(&old_entry->lock);
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mutex_unlock(&old_entry->group->mark_mutex);
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fsnotify_put_mark(chunk_entry);
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fsnotify_put_mark(old_entry);
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return -ENOSPC;
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}
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/* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */
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spin_lock(&chunk_entry->lock);
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spin_lock(&hash_lock);
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/* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */
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if (tree->goner) {
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spin_unlock(&hash_lock);
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chunk->dead = 1;
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spin_unlock(&chunk_entry->lock);
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spin_unlock(&old_entry->lock);
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mutex_unlock(&old_entry->group->mark_mutex);
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fsnotify_destroy_mark(chunk_entry, audit_tree_group);
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@ -485,8 +471,6 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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list_add(&tree->same_root, &chunk->trees);
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}
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spin_unlock(&hash_lock);
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spin_unlock(&chunk_entry->lock);
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spin_unlock(&old_entry->lock);
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mutex_unlock(&old_entry->group->mark_mutex);
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fsnotify_destroy_mark(old_entry, audit_tree_group);
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fsnotify_put_mark(chunk_entry); /* drop initial reference */
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