[XFS] implement semi-generic xfs_btree_new_root
From: Dave Chinner <dgc@sgi.com>
Add a xfs_btree_new_root helper for the alloc and ialloc btrees. The bmap
btree needs it's own version and is not converted.
[hch: split out from bigger patch and minor adaptions]
SGI-PV: 985583
SGI-Modid: xfs-linux-melb:xfs-kern:32200a
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Bill O'Donnell <billodo@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c
index 8057669..8de884c 100644
--- a/fs/xfs/xfs_btree.c
+++ b/fs/xfs/xfs_btree.c
@@ -2467,3 +2467,132 @@
XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
return error;
}
+
+/*
+ * Allocate a new root block, fill it in.
+ */
+int /* error */
+xfs_btree_new_root(
+ struct xfs_btree_cur *cur, /* btree cursor */
+ int *stat) /* success/failure */
+{
+ struct xfs_btree_block *block; /* one half of the old root block */
+ struct xfs_buf *bp; /* buffer containing block */
+ int error; /* error return value */
+ struct xfs_buf *lbp; /* left buffer pointer */
+ struct xfs_btree_block *left; /* left btree block */
+ struct xfs_buf *nbp; /* new (root) buffer */
+ struct xfs_btree_block *new; /* new (root) btree block */
+ int nptr; /* new value for key index, 1 or 2 */
+ struct xfs_buf *rbp; /* right buffer pointer */
+ struct xfs_btree_block *right; /* right btree block */
+ union xfs_btree_ptr rptr;
+ union xfs_btree_ptr lptr;
+
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
+ XFS_BTREE_STATS_INC(cur, newroot);
+
+ /* initialise our start point from the cursor */
+ cur->bc_ops->init_ptr_from_cur(cur, &rptr);
+
+ /* Allocate the new block. If we can't do it, we're toast. Give up. */
+ error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, 1, stat);
+ if (error)
+ goto error0;
+ if (*stat == 0)
+ goto out0;
+ XFS_BTREE_STATS_INC(cur, alloc);
+
+ /* Set up the new block. */
+ error = xfs_btree_get_buf_block(cur, &lptr, 0, &new, &nbp);
+ if (error)
+ goto error0;
+
+ /* Set the root in the holding structure increasing the level by 1. */
+ cur->bc_ops->set_root(cur, &lptr, 1);
+
+ /*
+ * At the previous root level there are now two blocks: the old root,
+ * and the new block generated when it was split. We don't know which
+ * one the cursor is pointing at, so we set up variables "left" and
+ * "right" for each case.
+ */
+ block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
+
+#ifdef DEBUG
+ error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
+ if (error)
+ goto error0;
+#endif
+
+ xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
+ if (!xfs_btree_ptr_is_null(cur, &rptr)) {
+ /* Our block is left, pick up the right block. */
+ lbp = bp;
+ xfs_btree_buf_to_ptr(cur, lbp, &lptr);
+ left = block;
+ error = xfs_btree_read_buf_block(cur, &rptr,
+ cur->bc_nlevels - 1, 0, &right, &rbp);
+ if (error)
+ goto error0;
+ bp = rbp;
+ nptr = 1;
+ } else {
+ /* Our block is right, pick up the left block. */
+ rbp = bp;
+ xfs_btree_buf_to_ptr(cur, rbp, &rptr);
+ right = block;
+ xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
+ error = xfs_btree_read_buf_block(cur, &lptr,
+ cur->bc_nlevels - 1, 0, &left, &lbp);
+ if (error)
+ goto error0;
+ bp = lbp;
+ nptr = 2;
+ }
+ /* Fill in the new block's btree header and log it. */
+ xfs_btree_init_block(cur, cur->bc_nlevels, 2, new);
+ xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
+ ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
+ !xfs_btree_ptr_is_null(cur, &rptr));
+
+ /* Fill in the key data in the new root. */
+ if (xfs_btree_get_level(left) > 0) {
+ xfs_btree_copy_keys(cur,
+ xfs_btree_key_addr(cur, 1, new),
+ xfs_btree_key_addr(cur, 1, left), 1);
+ xfs_btree_copy_keys(cur,
+ xfs_btree_key_addr(cur, 2, new),
+ xfs_btree_key_addr(cur, 1, right), 1);
+ } else {
+ cur->bc_ops->init_key_from_rec(
+ xfs_btree_key_addr(cur, 1, new),
+ xfs_btree_rec_addr(cur, 1, left));
+ cur->bc_ops->init_key_from_rec(
+ xfs_btree_key_addr(cur, 2, new),
+ xfs_btree_rec_addr(cur, 1, right));
+ }
+ xfs_btree_log_keys(cur, nbp, 1, 2);
+
+ /* Fill in the pointer data in the new root. */
+ xfs_btree_copy_ptrs(cur,
+ xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
+ xfs_btree_copy_ptrs(cur,
+ xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
+ xfs_btree_log_ptrs(cur, nbp, 1, 2);
+
+ /* Fix up the cursor. */
+ xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
+ cur->bc_ptrs[cur->bc_nlevels] = nptr;
+ cur->bc_nlevels++;
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+ *stat = 1;
+ return 0;
+error0:
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
+ return error;
+out0:
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+ *stat = 0;
+ return 0;
+}