[XFS] move xfs_bmbt_killroot to common code

xfs_bmbt_killroot is a mostly generic implementation of moving from a real
block based root to an inode based root. So move it to xfs_btree.c where
it can use all the nice infrastructure there and make it pointer size
agnostic

The new name for it is xfs_btree_kill_iroot, following the old naming but
making it clear we're dealing with the root in inode case here, and to
avoid confusion with xfs_btree_new_root which is used for the not inode
rooted case. I've also added a comment describing what it does and why
it's named the way it is.

SGI-PV: 985583

SGI-Modid: xfs-linux-melb:xfs-kern:32203a

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>

1 files changed, 32 insertions, 0 deletions

diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c
index 818adca77fc6..f124ddd91c08 100644
--- a/fs/xfs/xfs_alloc_btree.c
+++ b/fs/xfs/xfs_alloc_btree.c
@@ -834,6 +834,37 @@ xfs_allocbt_alloc_block(
         return 0;
 }
 
+STATIC int
+xfs_allocbt_free_block(
+        struct xfs_btree_cur    *cur,
+        struct xfs_buf          *bp)
+{
+        struct xfs_buf          *agbp = cur->bc_private.a.agbp;
+        struct xfs_agf          *agf = XFS_BUF_TO_AGF(agbp);
+        xfs_agblock_t           bno;
+        int                     error;
+
+        bno = XFS_DADDR_TO_AGBNO(cur->bc_mp, XFS_BUF_ADDR(bp));
+        error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
+        if (error)
+                return error;
+
+        /*
+         * Since blocks move to the free list without the coordination used in
+         * xfs_bmap_finish, we can't allow block to be available for
+         * reallocation and non-transaction writing (user data) until we know
+         * that the transaction that moved it to the free list is permanently
+         * on disk. We track the blocks by declaring these blocks as "busy";
+         * the busy list is maintained on a per-ag basis and each transaction
+         * records which entries should be removed when the iclog commits to
+         * disk. If a busy block is allocated, the iclog is pushed up to the
+         * LSN that freed the block.
+         */
+        xfs_alloc_mark_busy(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1);
+        xfs_trans_agbtree_delta(cur->bc_tp, -1);
+        return 0;
+}
+
 /*
  * Update the longest extent in the AGF
  */
@@ -1025,6 +1056,7 @@ static const struct xfs_btree_ops xfs_allocbt_ops = {
         .dup_cursor             = xfs_allocbt_dup_cursor,
         .set_root               = xfs_allocbt_set_root,
         .alloc_block            = xfs_allocbt_alloc_block,
+        .free_block             = xfs_allocbt_free_block,
         .update_lastrec         = xfs_allocbt_update_lastrec,
         .get_maxrecs            = xfs_allocbt_get_maxrecs,
         .init_key_from_rec      = xfs_allocbt_init_key_from_rec,