diff options
| author | Luis de Bethencourt <luisbg@osg.samsung.com> | 2016-03-30 23:18:14 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2016-05-06 15:22:49 +0200 |
| commit | 41b34accb265e3a20211a7a8ef3625678f1c6ec7 (patch) | |
| tree | 847946f18a22c72839832b78f76253d5185ed24c /fs/btrfs | |
| parent | ae02d1bd070767e109f4a6f1bb1f466e9698a355 (diff) | |
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: Luis de Bethencourt <luisbg@osg.samsung.com>
Suggested-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/super.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index bdca79ce45f1..fe03efb5bec0 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -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); - buf->f_bfree -= block_rsv->size >> bits; + /* 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); |