[XFS] implement generic xfs_btree_lookup
From: Dave Chinner <dgc@sgi.com>
[hch: split out from bigger patch and minor adaptions]
SGI-PV: 985583
SGI-Modid: xfs-linux-melb:xfs-kern:32192a
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_ialloc_btree.c b/fs/xfs/xfs_ialloc_btree.c
index 9099a32..161c3b2 100644
--- a/fs/xfs/xfs_ialloc_btree.c
+++ b/fs/xfs/xfs_ialloc_btree.c
@@ -829,212 +829,6 @@
}
/*
- * Lookup the record. The cursor is made to point to it, based on dir.
- * Return 0 if can't find any such record, 1 for success.
- */
-STATIC int /* error */
-xfs_inobt_lookup(
- xfs_btree_cur_t *cur, /* btree cursor */
- xfs_lookup_t dir, /* <=, ==, or >= */
- int *stat) /* success/failure */
-{
- xfs_agblock_t agbno; /* a.g. relative btree block number */
- xfs_agnumber_t agno; /* allocation group number */
- xfs_inobt_block_t *block=NULL; /* current btree block */
- __int64_t diff; /* difference for the current key */
- int error; /* error return value */
- int keyno=0; /* current key number */
- int level; /* level in the btree */
- xfs_mount_t *mp; /* file system mount point */
-
- /*
- * Get the allocation group header, and the root block number.
- */
- mp = cur->bc_mp;
- {
- xfs_agi_t *agi; /* a.g. inode header */
-
- agi = XFS_BUF_TO_AGI(cur->bc_private.a.agbp);
- agno = be32_to_cpu(agi->agi_seqno);
- agbno = be32_to_cpu(agi->agi_root);
- }
- /*
- * Iterate over each level in the btree, starting at the root.
- * For each level above the leaves, find the key we need, based
- * on the lookup record, then follow the corresponding block
- * pointer down to the next level.
- */
- for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
- xfs_buf_t *bp; /* buffer pointer for btree block */
- xfs_daddr_t d; /* disk address of btree block */
-
- /*
- * Get the disk address we're looking for.
- */
- d = XFS_AGB_TO_DADDR(mp, agno, agbno);
- /*
- * If the old buffer at this level is for a different block,
- * throw it away, otherwise just use it.
- */
- bp = cur->bc_bufs[level];
- if (bp && XFS_BUF_ADDR(bp) != d)
- bp = NULL;
- if (!bp) {
- /*
- * Need to get a new buffer. Read it, then
- * set it in the cursor, releasing the old one.
- */
- if ((error = xfs_btree_read_bufs(mp, cur->bc_tp,
- agno, agbno, 0, &bp, XFS_INO_BTREE_REF)))
- return error;
- xfs_btree_setbuf(cur, level, bp);
- /*
- * Point to the btree block, now that we have the buffer
- */
- block = XFS_BUF_TO_INOBT_BLOCK(bp);
- if ((error = xfs_btree_check_sblock(cur, block, level,
- bp)))
- return error;
- } else
- block = XFS_BUF_TO_INOBT_BLOCK(bp);
- /*
- * If we already had a key match at a higher level, we know
- * we need to use the first entry in this block.
- */
- if (diff == 0)
- keyno = 1;
- /*
- * Otherwise we need to search this block. Do a binary search.
- */
- else {
- int high; /* high entry number */
- xfs_inobt_key_t *kkbase=NULL;/* base of keys in block */
- xfs_inobt_rec_t *krbase=NULL;/* base of records in block */
- int low; /* low entry number */
-
- /*
- * Get a pointer to keys or records.
- */
- if (level > 0)
- kkbase = XFS_INOBT_KEY_ADDR(block, 1, cur);
- else
- krbase = XFS_INOBT_REC_ADDR(block, 1, cur);
- /*
- * Set low and high entry numbers, 1-based.
- */
- low = 1;
- if (!(high = be16_to_cpu(block->bb_numrecs))) {
- /*
- * If the block is empty, the tree must
- * be an empty leaf.
- */
- ASSERT(level == 0 && cur->bc_nlevels == 1);
- cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
- *stat = 0;
- return 0;
- }
- /*
- * Binary search the block.
- */
- while (low <= high) {
- xfs_agino_t startino; /* key value */
-
- /*
- * keyno is average of low and high.
- */
- keyno = (low + high) >> 1;
- /*
- * Get startino.
- */
- if (level > 0) {
- xfs_inobt_key_t *kkp;
-
- kkp = kkbase + keyno - 1;
- startino = be32_to_cpu(kkp->ir_startino);
- } else {
- xfs_inobt_rec_t *krp;
-
- krp = krbase + keyno - 1;
- startino = be32_to_cpu(krp->ir_startino);
- }
- /*
- * Compute difference to get next direction.
- */
- diff = (__int64_t)
- startino - cur->bc_rec.i.ir_startino;
- /*
- * Less than, move right.
- */
- if (diff < 0)
- low = keyno + 1;
- /*
- * Greater than, move left.
- */
- else if (diff > 0)
- high = keyno - 1;
- /*
- * Equal, we're done.
- */
- else
- break;
- }
- }
- /*
- * If there are more levels, set up for the next level
- * by getting the block number and filling in the cursor.
- */
- if (level > 0) {
- /*
- * If we moved left, need the previous key number,
- * unless there isn't one.
- */
- if (diff > 0 && --keyno < 1)
- keyno = 1;
- agbno = be32_to_cpu(*XFS_INOBT_PTR_ADDR(block, keyno, cur));
-#ifdef DEBUG
- if ((error = xfs_btree_check_sptr(cur, agbno, level)))
- return error;
-#endif
- cur->bc_ptrs[level] = keyno;
- }
- }
- /*
- * Done with the search.
- * See if we need to adjust the results.
- */
- if (dir != XFS_LOOKUP_LE && diff < 0) {
- keyno++;
- /*
- * If ge search and we went off the end of the block, but it's
- * not the last block, we're in the wrong block.
- */
- if (dir == XFS_LOOKUP_GE &&
- keyno > be16_to_cpu(block->bb_numrecs) &&
- be32_to_cpu(block->bb_rightsib) != NULLAGBLOCK) {
- int i;
-
- cur->bc_ptrs[0] = keyno;
- if ((error = xfs_btree_increment(cur, 0, &i)))
- return error;
- ASSERT(i == 1);
- *stat = 1;
- return 0;
- }
- }
- else if (dir == XFS_LOOKUP_LE && diff > 0)
- keyno--;
- cur->bc_ptrs[0] = keyno;
- /*
- * Return if we succeeded or not.
- */
- if (keyno == 0 || keyno > be16_to_cpu(block->bb_numrecs))
- *stat = 0;
- else
- *stat = ((dir != XFS_LOOKUP_EQ) || (diff == 0));
- return 0;
-}
-
-/*
* Move 1 record left from cur/level if possible.
* Update cur to reflect the new path.
*/
@@ -1798,59 +1592,6 @@
}
/*
- * Lookup the record equal to ino in the btree given by cur.
- */
-int /* error */
-xfs_inobt_lookup_eq(
- xfs_btree_cur_t *cur, /* btree cursor */
- xfs_agino_t ino, /* starting inode of chunk */
- __int32_t fcnt, /* free inode count */
- xfs_inofree_t free, /* free inode mask */
- int *stat) /* success/failure */
-{
- cur->bc_rec.i.ir_startino = ino;
- cur->bc_rec.i.ir_freecount = fcnt;
- cur->bc_rec.i.ir_free = free;
- return xfs_inobt_lookup(cur, XFS_LOOKUP_EQ, stat);
-}
-
-/*
- * Lookup the first record greater than or equal to ino
- * in the btree given by cur.
- */
-int /* error */
-xfs_inobt_lookup_ge(
- xfs_btree_cur_t *cur, /* btree cursor */
- xfs_agino_t ino, /* starting inode of chunk */
- __int32_t fcnt, /* free inode count */
- xfs_inofree_t free, /* free inode mask */
- int *stat) /* success/failure */
-{
- cur->bc_rec.i.ir_startino = ino;
- cur->bc_rec.i.ir_freecount = fcnt;
- cur->bc_rec.i.ir_free = free;
- return xfs_inobt_lookup(cur, XFS_LOOKUP_GE, stat);
-}
-
-/*
- * Lookup the first record less than or equal to ino
- * in the btree given by cur.
- */
-int /* error */
-xfs_inobt_lookup_le(
- xfs_btree_cur_t *cur, /* btree cursor */
- xfs_agino_t ino, /* starting inode of chunk */
- __int32_t fcnt, /* free inode count */
- xfs_inofree_t free, /* free inode mask */
- int *stat) /* success/failure */
-{
- cur->bc_rec.i.ir_startino = ino;
- cur->bc_rec.i.ir_freecount = fcnt;
- cur->bc_rec.i.ir_free = free;
- return xfs_inobt_lookup(cur, XFS_LOOKUP_LE, stat);
-}
-
-/*
* Update the record referred to by cur, to the value given
* by [ino, fcnt, free].
* This either works (return 0) or gets an EFSCORRUPTED error.
@@ -1918,6 +1659,38 @@
return cur->bc_mp->m_inobt_mxr[level != 0];
}
+STATIC void
+xfs_inobt_init_key_from_rec(
+ union xfs_btree_key *key,
+ union xfs_btree_rec *rec)
+{
+ key->inobt.ir_startino = rec->inobt.ir_startino;
+}
+
+/*
+ * intial value of ptr for lookup
+ */
+STATIC void
+xfs_inobt_init_ptr_from_cur(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *ptr)
+{
+ struct xfs_agi *agi = XFS_BUF_TO_AGI(cur->bc_private.a.agbp);
+
+ ASSERT(cur->bc_private.a.agno == be32_to_cpu(agi->agi_seqno));
+
+ ptr->s = agi->agi_root;
+}
+
+STATIC __int64_t
+xfs_inobt_key_diff(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_key *key)
+{
+ return (__int64_t)be32_to_cpu(key->inobt.ir_startino) -
+ cur->bc_rec.i.ir_startino;
+}
+
#ifdef XFS_BTREE_TRACE
ktrace_t *xfs_inobt_trace_buf;
@@ -1990,6 +1763,9 @@
.dup_cursor = xfs_inobt_dup_cursor,
.get_maxrecs = xfs_inobt_get_maxrecs,
+ .init_key_from_rec = xfs_inobt_init_key_from_rec,
+ .init_ptr_from_cur = xfs_inobt_init_ptr_from_cur,
+ .key_diff = xfs_inobt_key_diff,
#ifdef XFS_BTREE_TRACE
.trace_enter = xfs_inobt_trace_enter,