Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 89ce8a63 authored by Chris Mason's avatar Chris Mason
Browse files

Add btrfs_end_transaction_throttle to force writers to wait for pending commits 



The existing throttle mechanism was often not sufficient to prevent
new writers from coming in and making a given transaction run forever.
This adds an explicit wait at the end of most operations so they will
allow the current transaction to close.

There is no wait inside file_write, inode updates, or cow filling, all which
have different deadlock possibilities.

This is a temporary measure until better asynchronous commit support is
added.  This code leads to stalls as it waits for data=ordered
writeback, and it really needs to be fixed.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 333db94c

fs/btrfs/disk-io.c

+0 −18
Original line number Diff line number Diff line
@@ -1672,24 +1672,6 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf) 
	set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);

}



void btrfs_throttle(struct btrfs_root *root)

{

#if 0

	struct backing_dev_info *bdi;



	bdi = &root->fs_info->bdi;

	if (atomic_read(&root->fs_info->throttles) &&

	    bdi_write_congested(bdi)) {

#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18)

		congestion_wait(WRITE, HZ/20);

#else

		blk_congestion_wait(WRITE, HZ/20);

#endif



	}

#endif

}



void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)

{

	/*

fs/btrfs/disk-io.h

+0 −1
Original line number Diff line number Diff line
@@ -70,7 +70,6 @@ int btrfs_clear_buffer_defrag_done(struct extent_buffer *buf); 
int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid);

u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len);

void btrfs_csum_final(u32 crc, char *result);

void btrfs_throttle(struct btrfs_root *root);

int btrfs_open_device(struct btrfs_device *dev);

int btrfs_verify_block_csum(struct btrfs_root *root,

			    struct extent_buffer *buf);

fs/btrfs/file.c

+0 −1
Original line number Diff line number Diff line
@@ -934,7 +934,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf, 
		balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);

		if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)

			btrfs_btree_balance_dirty(root, 1);

		btrfs_throttle(root);

		cond_resched();

	}

out:

fs/btrfs/inode.c

+8 −16
Original line number Diff line number Diff line
@@ -855,10 +855,9 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry) 
		btrfs_del_ordered_inode(inode, 1);

	}



	btrfs_end_transaction(trans, root);

	btrfs_end_transaction_throttle(trans, root);

fail:

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return ret;

}
@@ -889,10 +888,9 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry) 
	}



	nr = trans->blocks_used;

	ret = btrfs_end_transaction(trans, root);

	ret = btrfs_end_transaction_throttle(trans, root);

fail:

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);



	if (ret && !err)

		err = ret;
@@ -1871,14 +1869,13 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry, 
	btrfs_update_inode_block_group(trans, dir);

out_unlock:

	nr = trans->blocks_used;

	btrfs_end_transaction(trans, root);

	btrfs_end_transaction_throttle(trans, root);

fail:

	if (drop_inode) {

		inode_dec_link_count(inode);

		iput(inode);

	}

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return err;

}
@@ -1936,14 +1933,13 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry, 
	btrfs_update_inode_block_group(trans, dir);

out_unlock:

	nr = trans->blocks_used;

	btrfs_end_transaction(trans, root);

	btrfs_end_transaction_throttle(trans, root);

fail:

	if (drop_inode) {

		inode_dec_link_count(inode);

		iput(inode);

	}

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return err;

}
@@ -1985,14 +1981,13 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir, 
		drop_inode = 1;



	nr = trans->blocks_used;

	btrfs_end_transaction(trans, root);

	btrfs_end_transaction_throttle(trans, root);

fail:

	if (drop_inode) {

		inode_dec_link_count(inode);

		iput(inode);

	}

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return err;

}
@@ -2055,13 +2050,12 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 


out_fail:

	nr = trans->blocks_used;

	btrfs_end_transaction(trans, root);

	btrfs_end_transaction_throttle(trans, root);



out_unlock:

	if (drop_on_err)

		iput(inode);

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return err;

}
@@ -2587,10 +2581,9 @@ static void btrfs_truncate(struct inode *inode) 
	btrfs_update_inode(trans, root, inode);

	nr = trans->blocks_used;



	ret = btrfs_end_transaction(trans, root);

	ret = btrfs_end_transaction_throttle(trans, root);

	BUG_ON(ret);

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

}



/*
@@ -2912,14 +2905,13 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry, 


out_unlock:

	nr = trans->blocks_used;

	btrfs_end_transaction(trans, root);

	btrfs_end_transaction_throttle(trans, root);

out_fail:

	if (drop_inode) {

		inode_dec_link_count(inode);

		iput(inode);

	}

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return err;

}

fs/btrfs/ioctl.c

+0 −2
Original line number Diff line number Diff line
@@ -164,7 +164,6 @@ static noinline int create_subvol(struct btrfs_root *root, char *name, 
		ret = err;

fail_commit:

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return ret;

}
@@ -206,7 +205,6 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen) 


fail_unlock:

	btrfs_btree_balance_dirty(root, nr);

	btrfs_throttle(root);

	return ret;

}