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Commit 5d5e103a authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
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Btrfs: fix possible ENOSPC problems with truncate 



There's a problem where we don't do any space reservation for truncates, which
can cause you to OOPs because you will be allowed to go off in the weeds a bit
since we don't account for the delalloc bytes that are created as a result of
the truncate.

Signed-off-by: default avatarJosef Bacik <jbacik@redhat.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 0eda294d

fs/btrfs/inode.c

+24 −3
Original line number Diff line number Diff line
@@ -3032,12 +3032,22 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from) 


	if ((offset & (blocksize - 1)) == 0)

		goto out;

	ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);

	if (ret)

		goto out;



	ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);

	if (ret)

		goto out;



	ret = -ENOMEM;

again:

	page = grab_cache_page(mapping, index);

	if (!page)

	if (!page) {

		btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);

		btrfs_unreserve_metadata_for_delalloc(root, inode, 1);

		goto out;

	}



	page_start = page_offset(page);

	page_end = page_start + PAGE_CACHE_SIZE - 1;
@@ -3070,6 +3080,10 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from) 
		goto again;

	}



	clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,

			  EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,

			  GFP_NOFS);



	ret = btrfs_set_extent_delalloc(inode, page_start, page_end);

	if (ret) {

		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
@@ -3088,6 +3102,9 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from) 
	unlock_extent(io_tree, page_start, page_end, GFP_NOFS);



out_unlock:

	if (ret)

		btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);

	btrfs_unreserve_metadata_for_delalloc(root, inode, 1);

	unlock_page(page);

	page_cache_release(page);

out:
@@ -3111,7 +3128,9 @@ int btrfs_cont_expand(struct inode *inode, loff_t size) 
	if (size <= hole_start)

		return 0;



	btrfs_truncate_page(inode->i_mapping, inode->i_size);

	err = btrfs_truncate_page(inode->i_mapping, inode->i_size);

	if (err)

		return err;



	while (1) {

		struct btrfs_ordered_extent *ordered;
@@ -5008,7 +5027,9 @@ static void btrfs_truncate(struct inode *inode) 
	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))

		return;



	btrfs_truncate_page(inode->i_mapping, inode->i_size);

	ret = btrfs_truncate_page(inode->i_mapping, inode->i_size);

	if (ret)

		return;

	btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);



	trans = btrfs_start_transaction(root, 1);