xfs: fix inode allocation block res calculation precedence

The block reservation calculation for inode allocation is supposed
to consist of the blocks required for the inode chunk plus
(maxlevels-1) of the inode btree multiplied by the number of inode
btrees in the fs (2 when finobt is enabled, 1 otherwise).

Instead, the macro returns (ialloc_blocks + 2) due to a precedence
error in the calculation logic. This leads to block reservation
overruns via generic/531 on small block filesystems with finobt
enabled. Add braces to fix the calculation and reserve the
appropriate number of blocks.

Fixes: 9d43b180af67 ("xfs: update inode allocation/free transaction reservations for finobt")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/xfs/libxfs/xfs_trans_space.h b/fs/xfs/libxfs/xfs_trans_space.h
index 88221c7a04ccfedd9a78aff832dbdef3ffb29673..c6df01a2a1585d2e16d2dd35f3cf02567ac6a228 100644 (file)
--- a/fs/xfs/libxfs/xfs_trans_space.h
+++ b/fs/xfs/libxfs/xfs_trans_space.h
@@ -57,7 +57,7 @@
        XFS_DAREMOVE_SPACE_RES(mp, XFS_DATA_FORK)
 #define        XFS_IALLOC_SPACE_RES(mp)        \
        (M_IGEO(mp)->ialloc_blks + \
-        (xfs_sb_version_hasfinobt(&mp->m_sb) ? 2 : 1 * \
+        ((xfs_sb_version_hasfinobt(&mp->m_sb) ? 2 : 1) * \
          (M_IGEO(mp)->inobt_maxlevels - 1)))
 
 /*