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| author | Luis de Bethencourt <luisbg@osg.samsung.com> | 2016-03-30 23:18:14 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-06-07 18:18:54 -0700 |
| commit | 30083555110d34cff755fb7845085b5c2adeb26a (patch) | |
| tree | d6c8cdae44ec65da62bf0f8b4f43481b08fc83a3 | |
| parent | 12e137029ba089da7cdef2f7ada60d8fd122c724 (diff) | |
| download | linux-30083555110d34cff755fb7845085b5c2adeb26a.tar.gz linux-30083555110d34cff755fb7845085b5c2adeb26a.zip | |
btrfs: avoid overflowing f_bfree
commit 41b34accb265e3a20211a7a8ef3625678f1c6ec7 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 4e6f842b5ad2..468e988d8110 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2073,7 +2073,11 @@ 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); |