xfs: hoist the node iroot update code out of xfs_btree_new_iroot

In preparation for allowing records in an inode btree root, hoist the
code that copies keyptrs from an existing node root into a child block
to a separate function.  Note that the new function explicitly computes
the keys of the new child block and stores that in the root block; while
the bmap btree could rely on leaving the key alone, realtime rmap needs
to set the new high key.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 44e60287dc7d9b65c97ed2ac1ddfbc5a61176ffc..098336eef5499ae70c74a4404d38528d716d33f0 100644 (file)
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -3078,6 +3078,78 @@ xfs_btree_split(
 #define xfs_btree_split        __xfs_btree_split
 #endif /* __KERNEL__ */
 
+/*
+ * Move the keys and pointers from a root block to a separate block.
+ *
+ * Since the keyptr size does not change, all we have to do is increase the
+ * tree height, copy the keyptrs to the new internal node (cblock), shrink
+ * the root, and copy the pointers there.
+ */
+STATIC int
+xfs_btree_promote_node_iroot(
+       struct xfs_btree_cur    *cur,
+       struct xfs_btree_block  *block,
+       int                     level,
+       struct xfs_buf          *cbp,
+       union xfs_btree_ptr     *cptr,
+       struct xfs_btree_block  *cblock)
+{
+       union xfs_btree_key     *ckp;
+       union xfs_btree_key     *kp;
+       union xfs_btree_ptr     *cpp;
+       union xfs_btree_ptr     *pp;
+       int                     i;
+       int                     error;
+       int                     numrecs = xfs_btree_get_numrecs(block);
+
+       /*
+        * Increase tree height, adjusting the root block level to match.
+        * We cannot change the root btree node size until we've copied the
+        * block contents to the new child block.
+        */
+       be16_add_cpu(&block->bb_level, 1);
+       cur->bc_nlevels++;
+       cur->bc_levels[level + 1].ptr = 1;
+
+       /*
+        * Adjust the root btree record count, then copy the keys from the old
+        * root to the new child block.
+        */
+       xfs_btree_set_numrecs(block, 1);
+       kp = xfs_btree_key_addr(cur, 1, block);
+       ckp = xfs_btree_key_addr(cur, 1, cblock);
+       xfs_btree_copy_keys(cur, ckp, kp, numrecs);
+
+       /* Check the pointers and copy them to the new child block. */
+       pp = xfs_btree_ptr_addr(cur, 1, block);
+       cpp = xfs_btree_ptr_addr(cur, 1, cblock);
+       for (i = 0; i < numrecs; i++) {
+               error = xfs_btree_debug_check_ptr(cur, pp, i, level);
+               if (error)
+                       return error;
+       }
+       xfs_btree_copy_ptrs(cur, cpp, pp, numrecs);
+
+       /*
+        * Set the first keyptr to point to the new child block, then shrink
+        * the memory buffer for the root block.
+        */
+       error = xfs_btree_debug_check_ptr(cur, cptr, 0, level);
+       if (error)
+               return error;
+       xfs_btree_copy_ptrs(cur, pp, cptr, 1);
+       xfs_btree_get_keys(cur, cblock, kp);
+
+       cur->bc_ops->broot_realloc(cur, 1);
+
+       /* Attach the new block to the cursor and log it. */
+       xfs_btree_setbuf(cur, level, cbp);
+       xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
+       xfs_btree_log_keys(cur, cbp, 1, numrecs);
+       xfs_btree_log_ptrs(cur, cbp, 1, numrecs);
+       return 0;
+}
+
 /*
  * Copy the old inode root contents into a real block and make the
  * broot point to it.
@@ -3091,14 +3163,10 @@ xfs_btree_new_iroot(
        struct xfs_buf          *cbp;           /* buffer for cblock */
        struct xfs_btree_block  *block;         /* btree block */
        struct xfs_btree_block  *cblock;        /* child btree block */
-       union xfs_btree_key     *ckp;           /* child key pointer */
-       union xfs_btree_ptr     *cpp;           /* child ptr pointer */
-       union xfs_btree_key     *kp;            /* pointer to btree key */
-       union xfs_btree_ptr     *pp;            /* pointer to block addr */
+       union xfs_btree_ptr     *pp;
        union xfs_btree_ptr     nptr;           /* new block addr */
        int                     level;          /* btree level */
        int                     error;          /* error return code */
-       int                     i;              /* loop counter */
 
        XFS_BTREE_STATS_INC(cur, newroot);
 
@@ -3136,45 +3204,12 @@ xfs_btree_new_iroot(
                        cblock->bb_u.s.bb_blkno = bno;
        }
 
-       be16_add_cpu(&block->bb_level, 1);
-       xfs_btree_set_numrecs(block, 1);
-       cur->bc_nlevels++;
-       ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
-       cur->bc_levels[level + 1].ptr = 1;
-
-       kp = xfs_btree_key_addr(cur, 1, block);
-       ckp = xfs_btree_key_addr(cur, 1, cblock);
-       xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
-
-       cpp = xfs_btree_ptr_addr(cur, 1, cblock);
-       for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
-               error = xfs_btree_debug_check_ptr(cur, pp, i, level);
-               if (error)
-                       goto error0;
-       }
-
-       xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
-
-       error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
+       error = xfs_btree_promote_node_iroot(cur, block, level, cbp, &nptr,
+                       cblock);
        if (error)
                goto error0;
 
-       xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
-
-       cur->bc_ops->broot_realloc(cur, 1);
-
-       xfs_btree_setbuf(cur, level, cbp);
-
-       /*
-        * Do all this logging at the end so that
-        * the root is at the right level.
-        */
-       xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
-       xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
-       xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
-
-       *logflags |=
-               XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
+       *logflags |= XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
        *stat = 1;
        return 0;
 error0: