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Commit 24bbcf04 authored by Yan, Zheng's avatar Yan, Zheng Committed by Chris Mason
Browse files

Btrfs: Add delayed iput 



iput() can trigger new transactions if we are dropping the
final reference, so calling it in btrfs_commit_transaction
may end up deadlock. This patch adds delayed iput to avoid
the issue.

Signed-off-by: default avatarYan Zheng <zheng.yan@oracle.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent f34f57a3

fs/btrfs/ctree.h

+6 −1
Original line number Diff line number Diff line
@@ -872,6 +872,9 @@ struct btrfs_fs_info { 
	struct list_head dead_roots;

	struct list_head caching_block_groups;



	spinlock_t delayed_iput_lock;

	struct list_head delayed_iputs;



	atomic_t nr_async_submits;

	atomic_t async_submit_draining;

	atomic_t nr_async_bios;
@@ -2301,7 +2304,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans, 
			       struct inode *inode, u64 new_size,

			       u32 min_type);



int btrfs_start_delalloc_inodes(struct btrfs_root *root);

int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput);

int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end);

int btrfs_writepages(struct address_space *mapping,

		     struct writeback_control *wbc);
@@ -2341,6 +2344,8 @@ int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode); 
void btrfs_orphan_cleanup(struct btrfs_root *root);

int btrfs_cont_expand(struct inode *inode, loff_t size);

int btrfs_invalidate_inodes(struct btrfs_root *root);

void btrfs_add_delayed_iput(struct inode *inode);

void btrfs_run_delayed_iputs(struct btrfs_root *root);

extern const struct dentry_operations btrfs_dentry_operations;



/* ioctl.c */

fs/btrfs/disk-io.c

+4 −0
Original line number Diff line number Diff line
@@ -1476,6 +1476,7 @@ static int cleaner_kthread(void *arg) 


		if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&

		    mutex_trylock(&root->fs_info->cleaner_mutex)) {

			btrfs_run_delayed_iputs(root);

			btrfs_clean_old_snapshots(root);

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

		}
@@ -1605,6 +1606,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, 
	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);

	INIT_LIST_HEAD(&fs_info->trans_list);

	INIT_LIST_HEAD(&fs_info->dead_roots);

	INIT_LIST_HEAD(&fs_info->delayed_iputs);

	INIT_LIST_HEAD(&fs_info->hashers);

	INIT_LIST_HEAD(&fs_info->delalloc_inodes);

	INIT_LIST_HEAD(&fs_info->ordered_operations);
@@ -1613,6 +1615,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, 
	spin_lock_init(&fs_info->new_trans_lock);

	spin_lock_init(&fs_info->ref_cache_lock);

	spin_lock_init(&fs_info->fs_roots_radix_lock);

	spin_lock_init(&fs_info->delayed_iput_lock);



	init_completion(&fs_info->kobj_unregister);

	fs_info->tree_root = tree_root;
@@ -2386,6 +2389,7 @@ int btrfs_commit_super(struct btrfs_root *root) 
	int ret;



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

	btrfs_run_delayed_iputs(root);

	btrfs_clean_old_snapshots(root);

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

fs/btrfs/extent-tree.c

+4 −4
Original line number Diff line number Diff line
@@ -2880,9 +2880,9 @@ static noinline void flush_delalloc_async(struct btrfs_work *work) 
	root = async->root;

	info = async->info;



	btrfs_start_delalloc_inodes(root);

	btrfs_start_delalloc_inodes(root, 0);

	wake_up(&info->flush_wait);

	btrfs_wait_ordered_extents(root, 0);

	btrfs_wait_ordered_extents(root, 0, 0);



	spin_lock(&info->lock);

	info->flushing = 0;
@@ -2956,8 +2956,8 @@ static void flush_delalloc(struct btrfs_root *root, 
	return;



flush:

	btrfs_start_delalloc_inodes(root);

	btrfs_wait_ordered_extents(root, 0);

	btrfs_start_delalloc_inodes(root, 0);

	btrfs_wait_ordered_extents(root, 0, 0);



	spin_lock(&info->lock);

	info->flushing = 0;

fs/btrfs/inode.c

+53 −2
Original line number Diff line number Diff line
@@ -2022,6 +2022,54 @@ static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end, 
	return -EIO;

}



struct delayed_iput {

	struct list_head list;

	struct inode *inode;

};



void btrfs_add_delayed_iput(struct inode *inode)

{

	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;

	struct delayed_iput *delayed;



	if (atomic_add_unless(&inode->i_count, -1, 1))

		return;



	delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);

	delayed->inode = inode;



	spin_lock(&fs_info->delayed_iput_lock);

	list_add_tail(&delayed->list, &fs_info->delayed_iputs);

	spin_unlock(&fs_info->delayed_iput_lock);

}



void btrfs_run_delayed_iputs(struct btrfs_root *root)

{

	LIST_HEAD(list);

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct delayed_iput *delayed;

	int empty;



	spin_lock(&fs_info->delayed_iput_lock);

	empty = list_empty(&fs_info->delayed_iputs);

	spin_unlock(&fs_info->delayed_iput_lock);

	if (empty)

		return;



	down_read(&root->fs_info->cleanup_work_sem);

	spin_lock(&fs_info->delayed_iput_lock);

	list_splice_init(&fs_info->delayed_iputs, &list);

	spin_unlock(&fs_info->delayed_iput_lock);



	while (!list_empty(&list)) {

		delayed = list_entry(list.next, struct delayed_iput, list);

		list_del(&delayed->list);

		iput(delayed->inode);

		kfree(delayed);

	}

	up_read(&root->fs_info->cleanup_work_sem);

}



/*

 * This creates an orphan entry for the given inode in case something goes

 * wrong in the middle of an unlink/truncate.
@@ -5568,7 +5616,7 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry, 
 * some fairly slow code that needs optimization. This walks the list

 * of all the inodes with pending delalloc and forces them to disk.

 */

int btrfs_start_delalloc_inodes(struct btrfs_root *root)

int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)

{

	struct list_head *head = &root->fs_info->delalloc_inodes;

	struct btrfs_inode *binode;
@@ -5587,6 +5635,9 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root) 
		spin_unlock(&root->fs_info->delalloc_lock);

		if (inode) {

			filemap_flush(inode->i_mapping);

			if (delay_iput)

				btrfs_add_delayed_iput(inode);

			else

				iput(inode);

		}

		cond_resched();

fs/btrfs/ordered-data.c

+7 −3
Original line number Diff line number Diff line
@@ -352,7 +352,8 @@ int btrfs_remove_ordered_extent(struct inode *inode, 
 * wait for all the ordered extents in a root.  This is done when balancing

 * space between drives.

 */

int btrfs_wait_ordered_extents(struct btrfs_root *root, int nocow_only)

int btrfs_wait_ordered_extents(struct btrfs_root *root,

			       int nocow_only, int delay_iput)

{

	struct list_head splice;

	struct list_head *cur;
@@ -389,6 +390,9 @@ int btrfs_wait_ordered_extents(struct btrfs_root *root, int nocow_only) 
		if (inode) {

			btrfs_start_ordered_extent(inode, ordered, 1);

			btrfs_put_ordered_extent(ordered);

			if (delay_iput)

				btrfs_add_delayed_iput(inode);

			else

				iput(inode);

		} else {

			btrfs_put_ordered_extent(ordered);
@@ -447,7 +451,7 @@ int btrfs_run_ordered_operations(struct btrfs_root *root, int wait) 
				btrfs_wait_ordered_range(inode, 0, (u64)-1);

			else

				filemap_flush(inode->i_mapping);

			iput(inode);

			btrfs_add_delayed_iput(inode);

		}



		cond_resched();