[PATCH] xfs: check on-disk (not incore) btree root size in dfrag.c

[Eric Sandeen <sandeen@xxxxxxxxxx>]

xfs_swap_extents_check_format() contains checks to make sure that
original and the temporary files during defrag are compatible;
Gabriel VLASIU ran into a case where xfs_fsr returned EINVAL
because the tests found the btree root to be of size 120,
while the fork offset was only 104; IOW, they overlapped.

However, this is just due to an error in the
xfs_swap_extents_check_format() tests, because it is checking
the in-memory btree root size against the on-disk fork offset.
We should be checking the on-disk sizes in both cases.

This patch adds a new macro to calculate this size, and uses
it in the tests.

With this change, the filesystem image provided by Gabriel
allows for proper file degragmentation.

Reported-by: Gabriel VLASIU <gabriel@xxxxxxxxxx>
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---

diff --git a/fs/xfs/xfs_bmap_btree.h b/fs/xfs/xfs_bmap_btree.h
index 0e66c4e..d9eeb64 100644
--- a/fs/xfs/xfs_bmap_btree.h
+++ b/fs/xfs/xfs_bmap_btree.h
@@ -189,12 +189,14 @@ typedef __be64 xfs_bmbt_ptr_t, xfs_bmdr_ptr_t;
 #define XFS_BMAP_BROOT_SPACE_CALC(nrecs) \
        (int)(XFS_BTREE_LBLOCK_LEN + \
               ((nrecs) * (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t))))
-
 #define XFS_BMAP_BROOT_SPACE(bb) \
        (XFS_BMAP_BROOT_SPACE_CALC(be16_to_cpu((bb)->bb_numrecs)))
+
 #define XFS_BMDR_SPACE_CALC(nrecs) \
        (int)(sizeof(xfs_bmdr_block_t) + \
               ((nrecs) * (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t))))
+#define XFS_BMAP_BMDR_SPACE(bb) \
+       (XFS_BMDR_SPACE_CALC(be16_to_cpu((bb)->bb_numrecs)))
 
 /*
  * Maximum number of bmap btree levels.
diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c
index dd974a5..2707d86 100644
--- a/fs/xfs/xfs_dfrag.c
+++ b/fs/xfs/xfs_dfrag.c
@@ -26,6 +26,9 @@
 #include "xfs_ag.h"
 #include "xfs_mount.h"
 #include "xfs_bmap_btree.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_btree.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_inode_item.h"
@@ -184,7 +187,7 @@ xfs_swap_extents_check_format(
         */
        if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
                if (XFS_IFORK_BOFF(ip) &&
-                   tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip))
+                   XFS_BMAP_BMDR_SPACE(tip->i_df.if_broot) > 
XFS_IFORK_BOFF(ip))
                        return EINVAL;
                if (XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <=
                    XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
@@ -194,9 +197,8 @@ xfs_swap_extents_check_format(
        /* Reciprocal target->temp btree format checks */
        if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
                if (XFS_IFORK_BOFF(tip) &&
-                   ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip))
+                   XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > 
XFS_IFORK_BOFF(tip))
                        return EINVAL;
-
                if (XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <=
                    XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
                        return EINVAL;