[XFS] implement generic xfs_btree_update
From: Dave Chinner <dgc@sgi.com>
The most complicated part here is the lastrec tracking for the alloc
btree. Most logic is in the update_lastrec method which has to do some
hopefully good enough dirty magic to maintain it.
[hch: split out from bigger patch and a rework of the lastrec
logic]
SGI-PV: 985583
SGI-Modid: xfs-linux-melb:xfs-kern:32194a
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 1459a2b..205272f 100644
--- a/fs/xfs/xfs_btree.c
+++ b/fs/xfs/xfs_btree.c
@@ -988,6 +988,30 @@
}
}
+/*
+ * Return true if ptr is the last record in the btree and
+ * we need to track updateѕ to this record. The decision
+ * will be further refined in the update_lastrec method.
+ */
+STATIC int
+xfs_btree_is_lastrec(
+ struct xfs_btree_cur *cur,
+ struct xfs_btree_block *block,
+ int level)
+{
+ union xfs_btree_ptr ptr;
+
+ if (level > 0)
+ return 0;
+ if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
+ return 0;
+
+ xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
+ if (!xfs_btree_ptr_is_null(cur, &ptr))
+ return 0;
+ return 1;
+}
+
STATIC xfs_daddr_t
xfs_btree_ptr_to_daddr(
struct xfs_btree_cur *cur,
@@ -1080,6 +1104,20 @@
}
/*
+ * Copy records from one btree block to another.
+ */
+STATIC void
+xfs_btree_copy_recs(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_rec *dst_rec,
+ union xfs_btree_rec *src_rec,
+ int numrecs)
+{
+ ASSERT(numrecs >= 0);
+ memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
+}
+
+/*
* Log key values from the btree block.
*/
STATIC void
@@ -1105,6 +1143,26 @@
}
/*
+ * Log record values from the btree block.
+ */
+STATIC void
+xfs_btree_log_recs(
+ struct xfs_btree_cur *cur,
+ struct xfs_buf *bp,
+ int first,
+ int last)
+{
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
+ XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
+
+ xfs_trans_log_buf(cur->bc_tp, bp,
+ xfs_btree_rec_offset(cur, first),
+ xfs_btree_rec_offset(cur, last + 1) - 1);
+
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+}
+
+/*
* Increment cursor by one record at the level.
* For nonzero levels the leaf-ward information is untouched.
*/
@@ -1576,3 +1634,66 @@
XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
return 0;
}
+
+/*
+ * Update the record referred to by cur to the value in the
+ * given record. This either works (return 0) or gets an
+ * EFSCORRUPTED error.
+ */
+int
+xfs_btree_update(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_rec *rec)
+{
+ struct xfs_btree_block *block;
+ struct xfs_buf *bp;
+ int error;
+ int ptr;
+ union xfs_btree_rec *rp;
+
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
+ XFS_BTREE_TRACE_ARGR(cur, rec);
+
+ /* Pick up the current block. */
+ block = xfs_btree_get_block(cur, 0, &bp);
+
+#ifdef DEBUG
+ error = xfs_btree_check_block(cur, block, 0, bp);
+ if (error)
+ goto error0;
+#endif
+ /* Get the address of the rec to be updated. */
+ ptr = cur->bc_ptrs[0];
+ rp = xfs_btree_rec_addr(cur, ptr, block);
+
+ /* Fill in the new contents and log them. */
+ xfs_btree_copy_recs(cur, rp, rec, 1);
+ xfs_btree_log_recs(cur, bp, ptr, ptr);
+
+ /*
+ * If we are tracking the last record in the tree and
+ * we are at the far right edge of the tree, update it.
+ */
+ if (xfs_btree_is_lastrec(cur, block, 0)) {
+ cur->bc_ops->update_lastrec(cur, block, rec,
+ ptr, LASTREC_UPDATE);
+ }
+
+ /* Updating first rec in leaf. Pass new key value up to our parent. */
+ if (ptr == 1) {
+ union xfs_btree_key key;
+
+ cur->bc_ops->init_key_from_rec(&key, rec);
+ error = xfs_btree_updkey(cur, &key, 1);
+ if (error)
+ goto error0;
+ }
+
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+ return 0;
+
+error0:
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
+ return error;
+}
+