xfs: Directory's data fork extent counter can never overflow

The maximum file size that can be represented by the data fork extent counter
in the worst case occurs when all extents are 1 block in length and each block
is 1KB in size.

With XFS_MAX_EXTCNT_DATA_FORK_SMALL representing maximum extent count and with
1KB sized blocks, a file can reach upto,
(2^31) * 1KB = 2TB

This is much larger than the theoretical maximum size of a directory
i.e. XFS_DIR2_SPACE_SIZE * 3 = ~96GB.

Since a directory's inode can never overflow its data fork extent counter,
this commit removes all the overflow checks associated with
it. xfs_dinode_verify() now performs a rough check to verify if a diretory's
data fork is larger than 96GB.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>

1 files changed, 0 insertions, 13 deletions

diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index fd5c3c2d77e0..6f9d69f8896e 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -40,19 +40,6 @@ struct xfs_ifork {
 #define XFS_IEXT_PUNCH_HOLE_CNT		(1)
 
 /*
- * Directory entry addition can cause the following,
- * 1. Data block can be added/removed.
- *    A new extent can cause extent count to increase by 1.
- * 2. Free disk block can be added/removed.
- *    Same behaviour as described above for Data block.
- * 3. Dabtree blocks.
- *    XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these can be new
- *    extents. Hence extent count can increase by XFS_DA_NODE_MAXDEPTH.
- */
-#define XFS_IEXT_DIR_MANIP_CNT(mp) \
-	((XFS_DA_NODE_MAXDEPTH + 1 + 1) * (mp)->m_dir_geo->fsbcount)
-
-/*
  * Adding/removing an xattr can cause XFS_DA_NODE_MAXDEPTH extents to
  * be added. One extra extent for dabtree in case a local attr is
  * large enough to cause a double split.  It can also cause extent