[XFS] implement generic xfs_btree_rshift
Make the btree right shift code generic. Based on a patch from David
Chinner with lots of changes to follow the original btree implementations
more closely. While this loses some of the generic helper routines for
inserting/moving/removing records it also solves some of the one off bugs
in the original code and makes it easier to verify.
SGI-PV: 985583
SGI-Modid: xfs-linux-melb:xfs-kern:32196a
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_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c
index c5c32999..31e4289 100644
--- a/fs/xfs/xfs_alloc_btree.c
+++ b/fs/xfs/xfs_alloc_btree.c
@@ -49,7 +49,6 @@
STATIC void xfs_alloc_log_recs(xfs_btree_cur_t *, xfs_buf_t *, int, int);
STATIC int xfs_alloc_lshift(xfs_btree_cur_t *, int, int *);
STATIC int xfs_alloc_newroot(xfs_btree_cur_t *, int *);
-STATIC int xfs_alloc_rshift(xfs_btree_cur_t *, int, int *);
STATIC int xfs_alloc_split(xfs_btree_cur_t *, int, xfs_agblock_t *,
xfs_alloc_key_t *, xfs_btree_cur_t **, int *);
@@ -391,7 +390,7 @@
*/
if (be16_to_cpu(left->bb_numrecs) - 1 >=
XFS_ALLOC_BLOCK_MINRECS(level, cur)) {
- if ((error = xfs_alloc_rshift(tcur, level, &i)))
+ if ((error = xfs_btree_rshift(tcur, level, &i)))
goto error0;
if (i) {
ASSERT(be16_to_cpu(block->bb_numrecs) >=
@@ -683,7 +682,7 @@
/*
* First, try shifting an entry to the right neighbor.
*/
- if ((error = xfs_alloc_rshift(cur, level, &i)))
+ if ((error = xfs_btree_rshift(cur, level, &i)))
return error;
if (i) {
/* nothing */
@@ -1233,137 +1232,6 @@
}
/*
- * Move 1 record right from cur/level if possible.
- * Update cur to reflect the new path.
- */
-STATIC int /* error */
-xfs_alloc_rshift(
- xfs_btree_cur_t *cur, /* btree cursor */
- int level, /* level to shift record on */
- int *stat) /* success/failure */
-{
- int error; /* error return value */
- int i; /* loop index */
- xfs_alloc_key_t key; /* key value for leaf level upward */
- xfs_buf_t *lbp; /* buffer for left (current) block */
- xfs_alloc_block_t *left; /* left (current) btree block */
- xfs_buf_t *rbp; /* buffer for right neighbor block */
- xfs_alloc_block_t *right; /* right neighbor btree block */
- xfs_alloc_key_t *rkp; /* key pointer for right block */
- xfs_btree_cur_t *tcur; /* temporary cursor */
-
- /*
- * Set up variables for this block as "left".
- */
- lbp = cur->bc_bufs[level];
- left = XFS_BUF_TO_ALLOC_BLOCK(lbp);
-#ifdef DEBUG
- if ((error = xfs_btree_check_sblock(cur, left, level, lbp)))
- return error;
-#endif
- /*
- * If we've got no right sibling then we can't shift an entry right.
- */
- if (be32_to_cpu(left->bb_rightsib) == NULLAGBLOCK) {
- *stat = 0;
- return 0;
- }
- /*
- * If the cursor entry is the one that would be moved, don't
- * do it... it's too complicated.
- */
- if (cur->bc_ptrs[level] >= be16_to_cpu(left->bb_numrecs)) {
- *stat = 0;
- return 0;
- }
- /*
- * Set up the right neighbor as "right".
- */
- if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
- cur->bc_private.a.agno, be32_to_cpu(left->bb_rightsib),
- 0, &rbp, XFS_ALLOC_BTREE_REF)))
- return error;
- right = XFS_BUF_TO_ALLOC_BLOCK(rbp);
- if ((error = xfs_btree_check_sblock(cur, right, level, rbp)))
- return error;
- /*
- * If it's full, it can't take another entry.
- */
- if (be16_to_cpu(right->bb_numrecs) == XFS_ALLOC_BLOCK_MAXRECS(level, cur)) {
- *stat = 0;
- return 0;
- }
- /*
- * Make a hole at the start of the right neighbor block, then
- * copy the last left block entry to the hole.
- */
- if (level > 0) {
- xfs_alloc_key_t *lkp; /* key pointer for left block */
- xfs_alloc_ptr_t *lpp; /* address pointer for left block */
- xfs_alloc_ptr_t *rpp; /* address pointer for right block */
-
- lkp = XFS_ALLOC_KEY_ADDR(left, be16_to_cpu(left->bb_numrecs), cur);
- lpp = XFS_ALLOC_PTR_ADDR(left, be16_to_cpu(left->bb_numrecs), cur);
- rkp = XFS_ALLOC_KEY_ADDR(right, 1, cur);
- rpp = XFS_ALLOC_PTR_ADDR(right, 1, cur);
-#ifdef DEBUG
- for (i = be16_to_cpu(right->bb_numrecs) - 1; i >= 0; i--) {
- if ((error = xfs_btree_check_sptr(cur, be32_to_cpu(rpp[i]), level)))
- return error;
- }
-#endif
- memmove(rkp + 1, rkp, be16_to_cpu(right->bb_numrecs) * sizeof(*rkp));
- memmove(rpp + 1, rpp, be16_to_cpu(right->bb_numrecs) * sizeof(*rpp));
-#ifdef DEBUG
- if ((error = xfs_btree_check_sptr(cur, be32_to_cpu(*lpp), level)))
- return error;
-#endif
- *rkp = *lkp;
- *rpp = *lpp;
- xfs_alloc_log_keys(cur, rbp, 1, be16_to_cpu(right->bb_numrecs) + 1);
- xfs_alloc_log_ptrs(cur, rbp, 1, be16_to_cpu(right->bb_numrecs) + 1);
- xfs_btree_check_key(cur->bc_btnum, rkp, rkp + 1);
- } else {
- xfs_alloc_rec_t *lrp; /* record pointer for left block */
- xfs_alloc_rec_t *rrp; /* record pointer for right block */
-
- lrp = XFS_ALLOC_REC_ADDR(left, be16_to_cpu(left->bb_numrecs), cur);
- rrp = XFS_ALLOC_REC_ADDR(right, 1, cur);
- memmove(rrp + 1, rrp, be16_to_cpu(right->bb_numrecs) * sizeof(*rrp));
- *rrp = *lrp;
- xfs_alloc_log_recs(cur, rbp, 1, be16_to_cpu(right->bb_numrecs) + 1);
- key.ar_startblock = rrp->ar_startblock;
- key.ar_blockcount = rrp->ar_blockcount;
- rkp = &key;
- xfs_btree_check_rec(cur->bc_btnum, rrp, rrp + 1);
- }
- /*
- * Decrement and log left's numrecs, bump and log right's numrecs.
- */
- be16_add_cpu(&left->bb_numrecs, -1);
- xfs_alloc_log_block(cur->bc_tp, lbp, XFS_BB_NUMRECS);
- be16_add_cpu(&right->bb_numrecs, 1);
- xfs_alloc_log_block(cur->bc_tp, rbp, XFS_BB_NUMRECS);
- /*
- * Using a temporary cursor, update the parent key values of the
- * block on the right.
- */
- if ((error = xfs_btree_dup_cursor(cur, &tcur)))
- return error;
- i = xfs_btree_lastrec(tcur, level);
- XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
- if ((error = xfs_btree_increment(tcur, level, &i)) ||
- (error = xfs_btree_updkey(tcur, (union xfs_btree_key *)rkp, level + 1)))
- goto error0;
- xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
- *stat = 1;
- return 0;
-error0:
- xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
- return error;
-}
-
-/*
* Split cur/level block in half.
* Return new block number and its first record (to be inserted into parent).
*/