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Commit 41b34acc authored by Luis de Bethencourt's avatar Luis de Bethencourt Committed by David Sterba
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btrfs: avoid overflowing f_bfree 



Since mixed block groups accounting isn't byte-accurate and f_bree is an
unsigned integer, it could overflow. Avoid this.

Signed-off-by: default avatarLuis de Bethencourt <luisbg@osg.samsung.com>
Suggested-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent ae02d1bd

fs/btrfs/super.c

+5 −1
Original line number Diff line number Diff line
@@ -2100,7 +2100,11 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 


	/* Account global block reserve as used, it's in logical size already */

	spin_lock(&block_rsv->lock);

	/* Mixed block groups accounting is not byte-accurate, avoid overflow */

	if (buf->f_bfree >= block_rsv->size >> bits)

		buf->f_bfree -= block_rsv->size >> bits;

	else

		buf->f_bfree = 0;

	spin_unlock(&block_rsv->lock);



	buf->f_bavail = div_u64(total_free_data, factor);