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linux-next/fs/btrfs/delayed-inode.h
Omar Sandoval 02dbfc99b4 Btrfs: fix ->iterate_shared() by upgrading i_rwsem for delayed nodes
Commit fe742fd4f9 ("Revert "btrfs: switch to ->iterate_shared()"")
backed out the conversion to ->iterate_shared() for Btrfs because the
delayed inode handling in btrfs_real_readdir() is racy. However, we can
still do readdir in parallel if there are no delayed nodes.

This is a temporary fix which upgrades the shared inode lock to an
exclusive lock only when we have delayed items until we come up with a
more complete solution. While we're here, rename the
btrfs_{get,put}_delayed_items functions to make it very clear that
they're just for readdir.

Tested with xfstests and by doing a parallel kernel build:

	while make tinyconfig && make -j4 && git clean dqfx; do
		:
	done

along with a bunch of parallel finds in another shell:

	while true; do
		for ((i=0; i<4; i++)); do
			find . >/dev/null &
		done
		wait
	done

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
2016-06-25 06:20:10 -07:00

159 lines
4.9 KiB
C

/*
* Copyright (C) 2011 Fujitsu. All rights reserved.
* Written by Miao Xie <miaox@cn.fujitsu.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef __DELAYED_TREE_OPERATION_H
#define __DELAYED_TREE_OPERATION_H
#include <linux/rbtree.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/atomic.h>
#include "ctree.h"
/* types of the delayed item */
#define BTRFS_DELAYED_INSERTION_ITEM 1
#define BTRFS_DELAYED_DELETION_ITEM 2
struct btrfs_delayed_root {
spinlock_t lock;
struct list_head node_list;
/*
* Used for delayed nodes which is waiting to be dealt with by the
* worker. If the delayed node is inserted into the work queue, we
* drop it from this list.
*/
struct list_head prepare_list;
atomic_t items; /* for delayed items */
atomic_t items_seq; /* for delayed items */
int nodes; /* for delayed nodes */
wait_queue_head_t wait;
};
#define BTRFS_DELAYED_NODE_IN_LIST 0
#define BTRFS_DELAYED_NODE_INODE_DIRTY 1
#define BTRFS_DELAYED_NODE_DEL_IREF 2
struct btrfs_delayed_node {
u64 inode_id;
u64 bytes_reserved;
struct btrfs_root *root;
/* Used to add the node into the delayed root's node list. */
struct list_head n_list;
/*
* Used to add the node into the prepare list, the nodes in this list
* is waiting to be dealt with by the async worker.
*/
struct list_head p_list;
struct rb_root ins_root;
struct rb_root del_root;
struct mutex mutex;
struct btrfs_inode_item inode_item;
atomic_t refs;
u64 index_cnt;
unsigned long flags;
int count;
};
struct btrfs_delayed_item {
struct rb_node rb_node;
struct btrfs_key key;
struct list_head tree_list; /* used for batch insert/delete items */
struct list_head readdir_list; /* used for readdir items */
u64 bytes_reserved;
struct btrfs_delayed_node *delayed_node;
atomic_t refs;
int ins_or_del;
u32 data_len;
char data[0];
};
static inline void btrfs_init_delayed_root(
struct btrfs_delayed_root *delayed_root)
{
atomic_set(&delayed_root->items, 0);
atomic_set(&delayed_root->items_seq, 0);
delayed_root->nodes = 0;
spin_lock_init(&delayed_root->lock);
init_waitqueue_head(&delayed_root->wait);
INIT_LIST_HEAD(&delayed_root->node_list);
INIT_LIST_HEAD(&delayed_root->prepare_list);
}
int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
struct btrfs_root *root, const char *name,
int name_len, struct inode *dir,
struct btrfs_disk_key *disk_key, u8 type,
u64 index);
int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *dir,
u64 index);
int btrfs_inode_delayed_dir_index_count(struct inode *inode);
int btrfs_run_delayed_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
int btrfs_run_delayed_items_nr(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int nr);
void btrfs_balance_delayed_items(struct btrfs_root *root);
int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
struct inode *inode);
/* Used for evicting the inode. */
void btrfs_remove_delayed_node(struct inode *inode);
void btrfs_kill_delayed_inode_items(struct inode *inode);
int btrfs_commit_inode_delayed_inode(struct inode *inode);
int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode);
int btrfs_fill_inode(struct inode *inode, u32 *rdev);
int btrfs_delayed_delete_inode_ref(struct inode *inode);
/* Used for drop dead root */
void btrfs_kill_all_delayed_nodes(struct btrfs_root *root);
/* Used for clean the transaction */
void btrfs_destroy_delayed_inodes(struct btrfs_root *root);
/* Used for readdir() */
bool btrfs_readdir_get_delayed_items(struct inode *inode,
struct list_head *ins_list,
struct list_head *del_list);
void btrfs_readdir_put_delayed_items(struct inode *inode,
struct list_head *ins_list,
struct list_head *del_list);
int btrfs_should_delete_dir_index(struct list_head *del_list,
u64 index);
int btrfs_readdir_delayed_dir_index(struct dir_context *ctx,
struct list_head *ins_list, bool *emitted);
/* for init */
int __init btrfs_delayed_inode_init(void);
void btrfs_delayed_inode_exit(void);
/* for debugging */
void btrfs_assert_delayed_root_empty(struct btrfs_root *root);
#endif