Commit 4d5e74bc authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Fix data=ordered vs wait_on_inode deadlock on older kernels 



Using ilookup5 during data=ordered writeback could deadlock on I_LOCK.  This
saves a pointer to the inode instead.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 2da98f00

fs/btrfs/ordered-data.c

+10 −2
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
struct tree_entry {

	u64 root_objectid;

	u64 objectid;

	struct inode *inode;

	struct rb_node rb_node;

};
@@ -144,6 +145,7 @@ int btrfs_add_ordered_inode(struct inode *inode) 
	write_lock(&tree->lock);

	entry->objectid = inode->i_ino;

	entry->root_objectid = root_objectid;

	entry->inode = inode;



	node = tree_insert(&tree->tree, root_objectid,

			   inode->i_ino, &entry->rb_node);
@@ -159,7 +161,8 @@ int btrfs_add_ordered_inode(struct inode *inode) 
}



int btrfs_find_first_ordered_inode(struct btrfs_ordered_inode_tree *tree,

				       u64 *root_objectid, u64 *objectid)

				   u64 *root_objectid, u64 *objectid,

				   struct inode **inode)

{

	struct tree_entry *entry;

	struct rb_node *node;
@@ -184,13 +187,16 @@ int btrfs_find_first_ordered_inode(struct btrfs_ordered_inode_tree *tree, 
	}



	*root_objectid = entry->root_objectid;

	*inode = entry->inode;

	atomic_inc(&entry->inode->i_count);

	*objectid = entry->objectid;

	write_unlock(&tree->lock);

	return 1;

}



int btrfs_find_del_first_ordered_inode(struct btrfs_ordered_inode_tree *tree,

				       u64 *root_objectid, u64 *objectid)

				       u64 *root_objectid, u64 *objectid,

				       struct inode **inode)

{

	struct tree_entry *entry;

	struct rb_node *node;
@@ -216,6 +222,8 @@ int btrfs_find_del_first_ordered_inode(struct btrfs_ordered_inode_tree *tree, 


	*root_objectid = entry->root_objectid;

	*objectid = entry->objectid;

	*inode = entry->inode;

	atomic_inc(&entry->inode->i_count);

	rb_erase(node, &tree->tree);

	write_unlock(&tree->lock);

	kfree(entry);

fs/btrfs/ordered-data.h

+4 −2
Original line number Diff line number Diff line
@@ -33,8 +33,10 @@ btrfs_ordered_inode_tree_init(struct btrfs_ordered_inode_tree *t) 


int btrfs_add_ordered_inode(struct inode *inode);

int btrfs_find_del_first_ordered_inode(struct btrfs_ordered_inode_tree *tree,

				       u64 *root_objectid, u64 *objectid);

				       u64 *root_objectid, u64 *objectid,

				       struct inode **inode);

int btrfs_find_first_ordered_inode(struct btrfs_ordered_inode_tree *tree,

				       u64 *root_objectid, u64 *objectid);

				       u64 *root_objectid, u64 *objectid,

				       struct inode **inode);

int btrfs_del_ordered_inode(struct inode *inode);

#endif

fs/btrfs/transaction.c

+13 −17
Original line number Diff line number Diff line
@@ -490,19 +490,17 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans, 
	while(1) {

		ret = btrfs_find_first_ordered_inode(

				&cur_trans->ordered_inode_tree,

				&root_objectid, &objectid);

				&root_objectid, &objectid, &inode);

		if (!ret)

			break;



		mutex_unlock(&root->fs_info->trans_mutex);

		mutex_unlock(&root->fs_info->fs_mutex);

		inode = btrfs_ilookup(root->fs_info->sb, objectid,

				      root_objectid);

		if (inode) {



		if (S_ISREG(inode->i_mode))

			filemap_fdatawrite(inode->i_mapping);

		iput(inode);

		}



		mutex_lock(&root->fs_info->fs_mutex);

		mutex_lock(&root->fs_info->trans_mutex);

	}
@@ -511,19 +509,17 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans, 
		objectid = 0;

		ret = btrfs_find_del_first_ordered_inode(

				&cur_trans->ordered_inode_tree,

				&root_objectid, &objectid);

				&root_objectid, &objectid, &inode);

		if (!ret)

			break;

		mutex_unlock(&root->fs_info->trans_mutex);

		mutex_unlock(&root->fs_info->fs_mutex);

		inode = btrfs_ilookup(root->fs_info->sb, objectid,

				      root_objectid);

		if (inode) {



		if (S_ISREG(inode->i_mode))

			filemap_write_and_wait(inode->i_mapping);

		atomic_dec(&inode->i_count);

		iput(inode);

		}



		mutex_lock(&root->fs_info->fs_mutex);

		mutex_lock(&root->fs_info->trans_mutex);

	}