[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>

1 files changed, 38 insertions, 68 deletions

diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c
index 28c6a698f562..c5c32999b810 100644
--- a/fs/xfs/xfs_alloc_btree.c
+++ b/fs/xfs/xfs_alloc_btree.c
@@ -1661,83 +1661,50 @@ xfs_alloc_insert(
         return 0;
 }
 
+STATIC struct xfs_btree_cur *
+xfs_allocbt_dup_cursor(
+        struct xfs_btree_cur    *cur)
+{
+        return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
+                        cur->bc_private.a.agbp, cur->bc_private.a.agno,
+                        cur->bc_btnum);
+}
+
 /*
- * Update the record referred to by cur, to the value given by [bno, len].
- * This either works (return 0) or gets an EFSCORRUPTED error.
+ * Update the longest extent in the AGF
  */
-int                                     /* error */
-xfs_alloc_update(
-        xfs_btree_cur_t         *cur,   /* btree cursor */
-        xfs_agblock_t           bno,    /* starting block of extent */
-        xfs_extlen_t            len)    /* length of extent */
+STATIC void
+xfs_allocbt_update_lastrec(
+        struct xfs_btree_cur    *cur,
+        struct xfs_btree_block  *block,
+        union xfs_btree_rec     *rec,
+        int                     ptr,
+        int                     reason)
 {
-        xfs_alloc_block_t       *block; /* btree block to update */
-        int                     error;  /* error return value */
-        int                     ptr;    /* current record number (updating) */
+        struct xfs_agf          *agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
+        xfs_agnumber_t          seqno = be32_to_cpu(agf->agf_seqno);
+        __be32                  len;
 
-        ASSERT(len > 0);
-        /*
-         * Pick up the a.g. freelist struct and the current block.
-         */
-        block = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[0]);
-#ifdef DEBUG
-        if ((error = xfs_btree_check_sblock(cur, block, 0, cur->bc_bufs[0])))
-                return error;
-#endif
-        /*
-         * Get the address of the rec to be updated.
-         */
-        ptr = cur->bc_ptrs[0];
-        {
-                xfs_alloc_rec_t         *rp;    /* pointer to updated record */
+        ASSERT(cur->bc_btnum == XFS_BTNUM_CNT);
 
-                rp = XFS_ALLOC_REC_ADDR(block, ptr, cur);
+        switch (reason) {
+        case LASTREC_UPDATE:
                 /*
-                 * Fill in the new contents and log them.
+                 * If this is the last leaf block and it's the last record,
+                 * then update the size of the longest extent in the AG.
                  */
-                rp->ar_startblock = cpu_to_be32(bno);
-                rp->ar_blockcount = cpu_to_be32(len);
-                xfs_alloc_log_recs(cur, cur->bc_bufs[0], ptr, ptr);
-        }
-        /*
-         * If it's the by-size btree and it's the last leaf block and
-         * it's the last record... then update the size of the longest
-         * extent in the a.g., which we cache in the a.g. freelist header.
-         */
-        if (cur->bc_btnum == XFS_BTNUM_CNT &&
-            be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK &&
-            ptr == be16_to_cpu(block->bb_numrecs)) {
-                xfs_agf_t       *agf;   /* a.g. freespace header */
-                xfs_agnumber_t  seqno;
-
-                agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
-                seqno = be32_to_cpu(agf->agf_seqno);
-                cur->bc_mp->m_perag[seqno].pagf_longest = len;
-                agf->agf_longest = cpu_to_be32(len);
-                xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp,
-                        XFS_AGF_LONGEST);
-        }
-        /*
-         * Updating first record in leaf. Pass new key value up to our parent.
-         */
-        if (ptr == 1) {
-                xfs_alloc_key_t key;    /* key containing [bno, len] */
-
-                key.ar_startblock = cpu_to_be32(bno);
-                key.ar_blockcount = cpu_to_be32(len);
-                if ((error = xfs_btree_updkey(cur, (union xfs_btree_key *)&key, 1)))
-                        return error;
+                if (ptr != xfs_btree_get_numrecs(block))
+                        return;
+                len = rec->alloc.ar_blockcount;
+                break;
+        default:
+                ASSERT(0);
+                return;
         }
-        return 0;
-}
 
-STATIC struct xfs_btree_cur *
-xfs_allocbt_dup_cursor(
-        struct xfs_btree_cur    *cur)
-{
-        return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
-                        cur->bc_private.a.agbp, cur->bc_private.a.agno,
-                        cur->bc_btnum);
+        agf->agf_longest = len;
+        cur->bc_mp->m_perag[seqno].pagf_longest = be32_to_cpu(len);
+        xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp, XFS_AGF_LONGEST);
 }
 
 STATIC int
@@ -1864,6 +1831,7 @@ static const struct xfs_btree_ops xfs_allocbt_ops = {
         .key_len                = sizeof(xfs_alloc_key_t),
 
         .dup_cursor             = xfs_allocbt_dup_cursor,
+        .update_lastrec         = xfs_allocbt_update_lastrec,
         .get_maxrecs            = xfs_allocbt_get_maxrecs,
         .init_key_from_rec      = xfs_allocbt_init_key_from_rec,
         .init_ptr_from_cur      = xfs_allocbt_init_ptr_from_cur,
@@ -1902,6 +1870,8 @@ xfs_allocbt_init_cursor(
         cur->bc_blocklog = mp->m_sb.sb_blocklog;
 
         cur->bc_ops = &xfs_allocbt_ops;
+        if (btnum == XFS_BTNUM_CNT)
+                cur->bc_flags = XFS_BTREE_LASTREC_UPDATE;
 
         cur->bc_private.a.agbp = agbp;
         cur->bc_private.a.agno = agno;