xfs: in btree_lshift, only allocate temporary cursor when needed

We only need the temporary cursor in _btree_lshift if we're shifting
in an overlapped btree.  Therefore, factor that into a single block
of code so we avoid unnecessary cursor duplication.

Also fix use of the wrong cursor when checking for corruption in
xfs_btree_rshift().

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 17 insertions, 17 deletions

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 40c19f82190c..b5c213a051cd 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -2397,29 +2397,29 @@ xfs_btree_lshift(
          * Using a temporary cursor, update the parent key values of the
          * block on the left.
          */
-        error = xfs_btree_dup_cursor(cur, &tcur);
-        if (error)
-                goto error0;
-        i = xfs_btree_firstrec(tcur, level);
-        XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
-
-        error = xfs_btree_decrement(tcur, level, &i);
-        if (error)
-                goto error1;
+        if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
+                error = xfs_btree_dup_cursor(cur, &tcur);
+                if (error)
+                        goto error0;
+                i = xfs_btree_firstrec(tcur, level);
+                XFS_WANT_CORRUPTED_GOTO(tcur->bc_mp, i == 1, error0);
 
-        /* Update the parent keys of the right block. */
-        error = xfs_btree_update_keys(cur, level);
-        if (error)
-                goto error1;
+                error = xfs_btree_decrement(tcur, level, &i);
+                if (error)
+                        goto error1;
 
-        /* Update the parent high keys of the left block, if needed. */
-        if (tcur->bc_flags & XFS_BTREE_OVERLAPPING) {
+                /* Update the parent high keys of the left block, if needed. */
                 error = xfs_btree_update_keys(tcur, level);
                 if (error)
                         goto error1;
+
+                xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
         }
 
-        xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
+        /* Update the parent keys of the right block. */
+        error = xfs_btree_update_keys(cur, level);
+        if (error)
+                goto error0;
 
         /* Slide the cursor value left one. */
         cur->bc_ptrs[level]--;
@@ -2580,7 +2580,7 @@ xfs_btree_rshift(
         if (error)
                 goto error0;
         i = xfs_btree_lastrec(tcur, level);
-        XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
+        XFS_WANT_CORRUPTED_GOTO(tcur->bc_mp, i == 1, error0);
 
         error = xfs_btree_increment(tcur, level, &i);
         if (error)