Commit a1fbc675 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by David Sterba
Browse files

btrfs: fix potential overflow in cluster_pages_for_defrag on 32bit arch 



On 32-bit systems, this shift will overflow for files larger than 4GB as
start_index is unsigned long while the calls to btrfs_delalloc_*_space
expect u64.

CC: stable@vger.kernel.org # 4.4+
Fixes: df480633 ("btrfs: extent-tree: Switch to new delalloc space reserve and release")
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
[ define the variable instead of repeating the shift ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent d5c82388

fs/btrfs/ioctl.c

+4 −6
Original line number Diff line number Diff line
@@ -1274,6 +1274,7 @@ static int cluster_pages_for_defrag(struct inode *inode, 
	u64 page_start;

	u64 page_end;

	u64 page_cnt;

	u64 start = (u64)start_index << PAGE_SHIFT;

	int ret;

	int i;

	int i_done;
@@ -1290,8 +1291,7 @@ static int cluster_pages_for_defrag(struct inode *inode, 
	page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);



	ret = btrfs_delalloc_reserve_space(BTRFS_I(inode), &data_reserved,

			start_index << PAGE_SHIFT,

			page_cnt << PAGE_SHIFT);

			start, page_cnt << PAGE_SHIFT);

	if (ret)

		return ret;

	i_done = 0;
@@ -1380,8 +1380,7 @@ again: 
		btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);

		spin_unlock(&BTRFS_I(inode)->lock);

		btrfs_delalloc_release_space(BTRFS_I(inode), data_reserved,

				start_index << PAGE_SHIFT,

				(page_cnt - i_done) << PAGE_SHIFT, true);

				start, (page_cnt - i_done) << PAGE_SHIFT, true);

	}
@@ -1408,8 +1407,7 @@ out: 
		put_page(pages[i]);

	}

	btrfs_delalloc_release_space(BTRFS_I(inode), data_reserved,

			start_index << PAGE_SHIFT,

			page_cnt << PAGE_SHIFT, true);

			start, page_cnt << PAGE_SHIFT, true);

	btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT);

	extent_changeset_free(data_reserved);

	return ret;

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