Merge tag 'md/4.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md
[cascardo/linux.git] / fs / xfs / libxfs / xfs_btree.c
index 07eeb0b..0856979 100644 (file)
@@ -23,6 +23,7 @@
 #include "xfs_trans_resv.h"
 #include "xfs_bit.h"
 #include "xfs_mount.h"
+#include "xfs_defer.h"
 #include "xfs_inode.h"
 #include "xfs_trans.h"
 #include "xfs_inode_item.h"
@@ -43,15 +44,14 @@ kmem_zone_t *xfs_btree_cur_zone;
  * Btree magic numbers.
  */
 static const __uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
-       { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
+       { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
          XFS_FIBT_MAGIC },
-       { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC,
+       { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
          XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC }
 };
 #define xfs_btree_magic(cur) \
        xfs_magics[!!((cur)->bc_flags & XFS_BTREE_CRC_BLOCKS)][cur->bc_btnum]
 
-
 STATIC int                             /* error (0 or EFSCORRUPTED) */
 xfs_btree_check_lblock(
        struct xfs_btree_cur    *cur,   /* btree cursor */
@@ -428,6 +428,50 @@ xfs_btree_dup_cursor(
  * into a btree block (xfs_btree_*_offset) or return a pointer to the given
  * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
  * inside the btree block is done using indices starting at one, not zero!
+ *
+ * If XFS_BTREE_OVERLAPPING is set, then this btree supports keys containing
+ * overlapping intervals.  In such a tree, records are still sorted lowest to
+ * highest and indexed by the smallest key value that refers to the record.
+ * However, nodes are different: each pointer has two associated keys -- one
+ * indexing the lowest key available in the block(s) below (the same behavior
+ * as the key in a regular btree) and another indexing the highest key
+ * available in the block(s) below.  Because records are /not/ sorted by the
+ * highest key, all leaf block updates require us to compute the highest key
+ * that matches any record in the leaf and to recursively update the high keys
+ * in the nodes going further up in the tree, if necessary.  Nodes look like
+ * this:
+ *
+ *             +--------+-----+-----+-----+-----+-----+-------+-------+-----+
+ * Non-Leaf:   | header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
+ *             +--------+-----+-----+-----+-----+-----+-------+-------+-----+
+ *
+ * To perform an interval query on an overlapped tree, perform the usual
+ * depth-first search and use the low and high keys to decide if we can skip
+ * that particular node.  If a leaf node is reached, return the records that
+ * intersect the interval.  Note that an interval query may return numerous
+ * entries.  For a non-overlapped tree, simply search for the record associated
+ * with the lowest key and iterate forward until a non-matching record is
+ * found.  Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
+ * Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
+ * more detail.
+ *
+ * Why do we care about overlapping intervals?  Let's say you have a bunch of
+ * reverse mapping records on a reflink filesystem:
+ *
+ * 1: +- file A startblock B offset C length D -----------+
+ * 2:      +- file E startblock F offset G length H --------------+
+ * 3:      +- file I startblock F offset J length K --+
+ * 4:                                                        +- file L... --+
+ *
+ * Now say we want to map block (B+D) into file A at offset (C+D).  Ideally,
+ * we'd simply increment the length of record 1.  But how do we find the record
+ * that ends at (B+D-1) (i.e. record 1)?  A LE lookup of (B+D-1) would return
+ * record 3 because the keys are ordered first by startblock.  An interval
+ * query would return records 1 and 2 because they both overlap (B+D-1), and
+ * from that we can pick out record 1 as the appropriate left neighbor.
+ *
+ * In the non-overlapped case you can do a LE lookup and decrement the cursor
+ * because a record's interval must end before the next record.
  */
 
 /*
@@ -478,6 +522,18 @@ xfs_btree_key_offset(
                (n - 1) * cur->bc_ops->key_len;
 }
 
+/*
+ * Calculate offset of the n-th high key in a btree block.
+ */
+STATIC size_t
+xfs_btree_high_key_offset(
+       struct xfs_btree_cur    *cur,
+       int                     n)
+{
+       return xfs_btree_block_len(cur) +
+               (n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
+}
+
 /*
  * Calculate offset of the n-th block pointer in a btree block.
  */
@@ -518,6 +574,19 @@ xfs_btree_key_addr(
                ((char *)block + xfs_btree_key_offset(cur, n));
 }
 
+/*
+ * Return a pointer to the n-th high key in the btree block.
+ */
+STATIC union xfs_btree_key *
+xfs_btree_high_key_addr(
+       struct xfs_btree_cur    *cur,
+       int                     n,
+       struct xfs_btree_block  *block)
+{
+       return (union xfs_btree_key *)
+               ((char *)block + xfs_btree_high_key_offset(cur, n));
+}
+
 /*
  * Return a pointer to the n-th block pointer in the btree block.
  */
@@ -1144,6 +1213,9 @@ xfs_btree_set_refs(
        case XFS_BTNUM_BMAP:
                xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
                break;
+       case XFS_BTNUM_RMAP:
+               xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
+               break;
        default:
                ASSERT(0);
        }
@@ -1742,6 +1814,10 @@ xfs_btree_lookup(
 
        XFS_BTREE_STATS_INC(cur, lookup);
 
+       /* No such thing as a zero-level tree. */
+       if (cur->bc_nlevels == 0)
+               return -EFSCORRUPTED;
+
        block = NULL;
        keyno = 0;
 
@@ -1879,32 +1955,214 @@ error0:
        return error;
 }
 
+/* Find the high key storage area from a regular key. */
+STATIC union xfs_btree_key *
+xfs_btree_high_key_from_key(
+       struct xfs_btree_cur    *cur,
+       union xfs_btree_key     *key)
+{
+       ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
+       return (union xfs_btree_key *)((char *)key +
+                       (cur->bc_ops->key_len / 2));
+}
+
+/* Determine the low (and high if overlapped) keys of a leaf block */
+STATIC void
+xfs_btree_get_leaf_keys(
+       struct xfs_btree_cur    *cur,
+       struct xfs_btree_block  *block,
+       union xfs_btree_key     *key)
+{
+       union xfs_btree_key     max_hkey;
+       union xfs_btree_key     hkey;
+       union xfs_btree_rec     *rec;
+       union xfs_btree_key     *high;
+       int                     n;
+
+       rec = xfs_btree_rec_addr(cur, 1, block);
+       cur->bc_ops->init_key_from_rec(key, rec);
+
+       if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
+
+               cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
+               for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
+                       rec = xfs_btree_rec_addr(cur, n, block);
+                       cur->bc_ops->init_high_key_from_rec(&hkey, rec);
+                       if (cur->bc_ops->diff_two_keys(cur, &hkey, &max_hkey)
+                                       > 0)
+                               max_hkey = hkey;
+               }
+
+               high = xfs_btree_high_key_from_key(cur, key);
+               memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
+       }
+}
+
+/* Determine the low (and high if overlapped) keys of a node block */
+STATIC void
+xfs_btree_get_node_keys(
+       struct xfs_btree_cur    *cur,
+       struct xfs_btree_block  *block,
+       union xfs_btree_key     *key)
+{
+       union xfs_btree_key     *hkey;
+       union xfs_btree_key     *max_hkey;
+       union xfs_btree_key     *high;
+       int                     n;
+
+       if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
+               memcpy(key, xfs_btree_key_addr(cur, 1, block),
+                               cur->bc_ops->key_len / 2);
+
+               max_hkey = xfs_btree_high_key_addr(cur, 1, block);
+               for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
+                       hkey = xfs_btree_high_key_addr(cur, n, block);
+                       if (cur->bc_ops->diff_two_keys(cur, hkey, max_hkey) > 0)
+                               max_hkey = hkey;
+               }
+
+               high = xfs_btree_high_key_from_key(cur, key);
+               memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
+       } else {
+               memcpy(key, xfs_btree_key_addr(cur, 1, block),
+                               cur->bc_ops->key_len);
+       }
+}
+
+/* Derive the keys for any btree block. */
+STATIC void
+xfs_btree_get_keys(
+       struct xfs_btree_cur    *cur,
+       struct xfs_btree_block  *block,
+       union xfs_btree_key     *key)
+{
+       if (be16_to_cpu(block->bb_level) == 0)
+               xfs_btree_get_leaf_keys(cur, block, key);
+       else
+               xfs_btree_get_node_keys(cur, block, key);
+}
+
+/*
+ * Decide if we need to update the parent keys of a btree block.  For
+ * a standard btree this is only necessary if we're updating the first
+ * record/key.  For an overlapping btree, we must always update the
+ * keys because the highest key can be in any of the records or keys
+ * in the block.
+ */
+static inline bool
+xfs_btree_needs_key_update(
+       struct xfs_btree_cur    *cur,
+       int                     ptr)
+{
+       return (cur->bc_flags & XFS_BTREE_OVERLAPPING) || ptr == 1;
+}
+
+/*
+ * Update the low and high parent keys of the given level, progressing
+ * towards the root.  If force_all is false, stop if the keys for a given
+ * level do not need updating.
+ */
+STATIC int
+__xfs_btree_updkeys(
+       struct xfs_btree_cur    *cur,
+       int                     level,
+       struct xfs_btree_block  *block,
+       struct xfs_buf          *bp0,
+       bool                    force_all)
+{
+       union xfs_btree_bigkey  key;    /* keys from current level */
+       union xfs_btree_key     *lkey;  /* keys from the next level up */
+       union xfs_btree_key     *hkey;
+       union xfs_btree_key     *nlkey; /* keys from the next level up */
+       union xfs_btree_key     *nhkey;
+       struct xfs_buf          *bp;
+       int                     ptr;
+
+       ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
+
+       /* Exit if there aren't any parent levels to update. */
+       if (level + 1 >= cur->bc_nlevels)
+               return 0;
+
+       trace_xfs_btree_updkeys(cur, level, bp0);
+
+       lkey = (union xfs_btree_key *)&key;
+       hkey = xfs_btree_high_key_from_key(cur, lkey);
+       xfs_btree_get_keys(cur, block, lkey);
+       for (level++; level < cur->bc_nlevels; level++) {
+#ifdef DEBUG
+               int             error;
+#endif
+               block = xfs_btree_get_block(cur, level, &bp);
+               trace_xfs_btree_updkeys(cur, level, bp);
+#ifdef DEBUG
+               error = xfs_btree_check_block(cur, block, level, bp);
+               if (error) {
+                       XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
+                       return error;
+               }
+#endif
+               ptr = cur->bc_ptrs[level];
+               nlkey = xfs_btree_key_addr(cur, ptr, block);
+               nhkey = xfs_btree_high_key_addr(cur, ptr, block);
+               if (!force_all &&
+                   !(cur->bc_ops->diff_two_keys(cur, nlkey, lkey) != 0 ||
+                     cur->bc_ops->diff_two_keys(cur, nhkey, hkey) != 0))
+                       break;
+               xfs_btree_copy_keys(cur, nlkey, lkey, 1);
+               xfs_btree_log_keys(cur, bp, ptr, ptr);
+               if (level + 1 >= cur->bc_nlevels)
+                       break;
+               xfs_btree_get_node_keys(cur, block, lkey);
+       }
+
+       return 0;
+}
+
+/* Update all the keys from some level in cursor back to the root. */
+STATIC int
+xfs_btree_updkeys_force(
+       struct xfs_btree_cur    *cur,
+       int                     level)
+{
+       struct xfs_buf          *bp;
+       struct xfs_btree_block  *block;
+
+       block = xfs_btree_get_block(cur, level, &bp);
+       return __xfs_btree_updkeys(cur, level, block, bp, true);
+}
+
 /*
- * Update keys at all levels from here to the root along the cursor's path.
+ * Update the parent keys of the given level, progressing towards the root.
  */
 STATIC int
-xfs_btree_updkey(
+xfs_btree_update_keys(
        struct xfs_btree_cur    *cur,
-       union xfs_btree_key     *keyp,
        int                     level)
 {
        struct xfs_btree_block  *block;
        struct xfs_buf          *bp;
        union xfs_btree_key     *kp;
+       union xfs_btree_key     key;
        int                     ptr;
 
+       ASSERT(level >= 0);
+
+       block = xfs_btree_get_block(cur, level, &bp);
+       if (cur->bc_flags & XFS_BTREE_OVERLAPPING)
+               return __xfs_btree_updkeys(cur, level, block, bp, false);
+
        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
        XFS_BTREE_TRACE_ARGIK(cur, level, keyp);
 
-       ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) || level >= 1);
-
        /*
         * Go up the tree from this level toward the root.
         * At each level, update the key value to the value input.
         * Stop when we reach a level where the cursor isn't pointing
         * at the first entry in the block.
         */
-       for (ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
+       xfs_btree_get_keys(cur, block, &key);
+       for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
 #ifdef DEBUG
                int             error;
 #endif
@@ -1918,7 +2176,7 @@ xfs_btree_updkey(
 #endif
                ptr = cur->bc_ptrs[level];
                kp = xfs_btree_key_addr(cur, ptr, block);
-               xfs_btree_copy_keys(cur, kp, keyp, 1);
+               xfs_btree_copy_keys(cur, kp, &key, 1);
                xfs_btree_log_keys(cur, bp, ptr, ptr);
        }
 
@@ -1970,12 +2228,9 @@ xfs_btree_update(
                                            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);
+       /* Pass new key value up to our parent. */
+       if (xfs_btree_needs_key_update(cur, ptr)) {
+               error = xfs_btree_update_keys(cur, 0);
                if (error)
                        goto error0;
        }
@@ -1998,18 +2253,19 @@ xfs_btree_lshift(
        int                     level,
        int                     *stat)          /* success/failure */
 {
-       union xfs_btree_key     key;            /* btree key */
        struct xfs_buf          *lbp;           /* left buffer pointer */
        struct xfs_btree_block  *left;          /* left btree block */
        int                     lrecs;          /* left record count */
        struct xfs_buf          *rbp;           /* right buffer pointer */
        struct xfs_btree_block  *right;         /* right btree block */
+       struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
        int                     rrecs;          /* right record count */
        union xfs_btree_ptr     lptr;           /* left btree pointer */
        union xfs_btree_key     *rkp = NULL;    /* right btree key */
        union xfs_btree_ptr     *rpp = NULL;    /* right address pointer */
        union xfs_btree_rec     *rrp = NULL;    /* right record pointer */
        int                     error;          /* error return value */
+       int                     i;
 
        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
        XFS_BTREE_TRACE_ARGI(cur, level);
@@ -2139,18 +2395,33 @@ xfs_btree_lshift(
                        xfs_btree_rec_addr(cur, 2, right),
                        -1, rrecs);
                xfs_btree_log_recs(cur, rbp, 1, rrecs);
+       }
 
-               /*
-                * If it's the first record in the block, we'll need a key
-                * structure to pass up to the next level (updkey).
-                */
-               cur->bc_ops->init_key_from_rec(&key,
-                       xfs_btree_rec_addr(cur, 1, right));
-               rkp = &key;
+       /*
+        * Using a temporary cursor, update the parent key values of the
+        * block on the left.
+        */
+       if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
+               error = xfs_btree_dup_cursor(cur, &tcur);
+               if (error)
+                       goto error0;
+               i = xfs_btree_firstrec(tcur, level);
+               XFS_WANT_CORRUPTED_GOTO(tcur->bc_mp, i == 1, error0);
+
+               error = xfs_btree_decrement(tcur, level, &i);
+               if (error)
+                       goto error1;
+
+               /* Update the parent high keys of the left block, if needed. */
+               error = xfs_btree_update_keys(tcur, level);
+               if (error)
+                       goto error1;
+
+               xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
        }
 
-       /* Update the parent key values of right. */
-       error = xfs_btree_updkey(cur, rkp, level + 1);
+       /* Update the parent keys of the right block. */
+       error = xfs_btree_update_keys(cur, level);
        if (error)
                goto error0;
 
@@ -2169,6 +2440,11 @@ out0:
 error0:
        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
        return error;
+
+error1:
+       XFS_BTREE_TRACE_CURSOR(tcur, XBT_ERROR);
+       xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
+       return error;
 }
 
 /*
@@ -2181,7 +2457,6 @@ xfs_btree_rshift(
        int                     level,
        int                     *stat)          /* success/failure */
 {
-       union xfs_btree_key     key;            /* btree key */
        struct xfs_buf          *lbp;           /* left buffer pointer */
        struct xfs_btree_block  *left;          /* left btree block */
        struct xfs_buf          *rbp;           /* right buffer pointer */
@@ -2290,12 +2565,6 @@ xfs_btree_rshift(
                /* Now put the new data in, and log it. */
                xfs_btree_copy_recs(cur, rrp, lrp, 1);
                xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
-
-               cur->bc_ops->init_key_from_rec(&key, rrp);
-               rkp = &key;
-
-               ASSERT(cur->bc_ops->recs_inorder(cur, rrp,
-                       xfs_btree_rec_addr(cur, 2, right)));
        }
 
        /*
@@ -2315,13 +2584,21 @@ xfs_btree_rshift(
        if (error)
                goto error0;
        i = xfs_btree_lastrec(tcur, level);
-       XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
+       XFS_WANT_CORRUPTED_GOTO(tcur->bc_mp, i == 1, error0);
 
        error = xfs_btree_increment(tcur, level, &i);
        if (error)
                goto error1;
 
-       error = xfs_btree_updkey(tcur, rkp, level + 1);
+       /* Update the parent high keys of the left block, if needed. */
+       if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
+               error = xfs_btree_update_keys(cur, level);
+               if (error)
+                       goto error1;
+       }
+
+       /* Update the parent keys of the right block. */
+       error = xfs_btree_update_keys(tcur, level);
        if (error)
                goto error1;
 
@@ -2422,6 +2699,11 @@ __xfs_btree_split(
 
        XFS_BTREE_STATS_ADD(cur, moves, rrecs);
 
+       /* Adjust numrecs for the later get_*_keys() calls. */
+       lrecs -= rrecs;
+       xfs_btree_set_numrecs(left, lrecs);
+       xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
+
        /*
         * Copy btree block entries from the left block over to the
         * new block, the right. Update the right block and log the
@@ -2447,14 +2729,15 @@ __xfs_btree_split(
                }
 #endif
 
+               /* Copy the keys & pointers to the new block. */
                xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
                xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
 
                xfs_btree_log_keys(cur, rbp, 1, rrecs);
                xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
 
-               /* Grab the keys to the entries moved to the right block */
-               xfs_btree_copy_keys(cur, key, rkp, 1);
+               /* Stash the keys of the new block for later insertion. */
+               xfs_btree_get_node_keys(cur, right, key);
        } else {
                /* It's a leaf.  Move records.  */
                union xfs_btree_rec     *lrp;   /* left record pointer */
@@ -2463,27 +2746,23 @@ __xfs_btree_split(
                lrp = xfs_btree_rec_addr(cur, src_index, left);
                rrp = xfs_btree_rec_addr(cur, 1, right);
 
+               /* Copy records to the new block. */
                xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
                xfs_btree_log_recs(cur, rbp, 1, rrecs);
 
-               cur->bc_ops->init_key_from_rec(key,
-                       xfs_btree_rec_addr(cur, 1, right));
+               /* Stash the keys of the new block for later insertion. */
+               xfs_btree_get_leaf_keys(cur, right, key);
        }
 
-
        /*
         * Find the left block number by looking in the buffer.
-        * Adjust numrecs, sibling pointers.
+        * Adjust sibling pointers.
         */
        xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
        xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
        xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
        xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
 
-       lrecs -= rrecs;
-       xfs_btree_set_numrecs(left, lrecs);
-       xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
-
        xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
        xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
 
@@ -2499,6 +2778,14 @@ __xfs_btree_split(
                xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
                xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
        }
+
+       /* Update the parent high keys of the left block, if needed. */
+       if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
+               error = xfs_btree_update_keys(cur, level);
+               if (error)
+                       goto error0;
+       }
+
        /*
         * If the cursor is really in the right block, move it there.
         * If it's just pointing past the last entry in left, then we'll
@@ -2802,6 +3089,7 @@ xfs_btree_new_root(
                bp = lbp;
                nptr = 2;
        }
+
        /* Fill in the new block's btree header and log it. */
        xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
        xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
@@ -2810,19 +3098,24 @@ xfs_btree_new_root(
 
        /* Fill in the key data in the new root. */
        if (xfs_btree_get_level(left) > 0) {
-               xfs_btree_copy_keys(cur,
-                               xfs_btree_key_addr(cur, 1, new),
-                               xfs_btree_key_addr(cur, 1, left), 1);
-               xfs_btree_copy_keys(cur,
-                               xfs_btree_key_addr(cur, 2, new),
-                               xfs_btree_key_addr(cur, 1, right), 1);
+               /*
+                * Get the keys for the left block's keys and put them directly
+                * in the parent block.  Do the same for the right block.
+                */
+               xfs_btree_get_node_keys(cur, left,
+                               xfs_btree_key_addr(cur, 1, new));
+               xfs_btree_get_node_keys(cur, right,
+                               xfs_btree_key_addr(cur, 2, new));
        } else {
-               cur->bc_ops->init_key_from_rec(
-                               xfs_btree_key_addr(cur, 1, new),
-                               xfs_btree_rec_addr(cur, 1, left));
-               cur->bc_ops->init_key_from_rec(
-                               xfs_btree_key_addr(cur, 2, new),
-                               xfs_btree_rec_addr(cur, 1, right));
+               /*
+                * Get the keys for the left block's records and put them
+                * directly in the parent block.  Do the same for the right
+                * block.
+                */
+               xfs_btree_get_leaf_keys(cur, left,
+                       xfs_btree_key_addr(cur, 1, new));
+               xfs_btree_get_leaf_keys(cur, right,
+                       xfs_btree_key_addr(cur, 2, new));
        }
        xfs_btree_log_keys(cur, nbp, 1, 2);
 
@@ -2858,10 +3151,9 @@ xfs_btree_make_block_unfull(
        int                     *index, /* new tree index */
        union xfs_btree_ptr     *nptr,  /* new btree ptr */
        struct xfs_btree_cur    **ncur, /* new btree cursor */
-       union xfs_btree_rec     *nrec,  /* new record */
+       union xfs_btree_key     *key,   /* key of new block */
        int                     *stat)
 {
-       union xfs_btree_key     key;    /* new btree key value */
        int                     error = 0;
 
        if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
@@ -2871,6 +3163,7 @@ xfs_btree_make_block_unfull(
                if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
                        /* A root block that can be made bigger. */
                        xfs_iroot_realloc(ip, 1, cur->bc_private.b.whichfork);
+                       *stat = 1;
                } else {
                        /* A root block that needs replacing */
                        int     logflags = 0;
@@ -2906,13 +3199,12 @@ xfs_btree_make_block_unfull(
         * If this works we have to re-set our variables because we
         * could be in a different block now.
         */
-       error = xfs_btree_split(cur, level, nptr, &key, ncur, stat);
+       error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
        if (error || *stat == 0)
                return error;
 
 
        *index = cur->bc_ptrs[level];
-       cur->bc_ops->init_rec_from_key(&key, nrec);
        return 0;
 }
 
@@ -2925,16 +3217,17 @@ xfs_btree_insrec(
        struct xfs_btree_cur    *cur,   /* btree cursor */
        int                     level,  /* level to insert record at */
        union xfs_btree_ptr     *ptrp,  /* i/o: block number inserted */
-       union xfs_btree_rec     *recp,  /* i/o: record data inserted */
+       union xfs_btree_rec     *rec,   /* record to insert */
+       union xfs_btree_key     *key,   /* i/o: block key for ptrp */
        struct xfs_btree_cur    **curp, /* output: new cursor replacing cur */
        int                     *stat)  /* success/failure */
 {
        struct xfs_btree_block  *block; /* btree block */
        struct xfs_buf          *bp;    /* buffer for block */
-       union xfs_btree_key     key;    /* btree key */
        union xfs_btree_ptr     nptr;   /* new block ptr */
        struct xfs_btree_cur    *ncur;  /* new btree cursor */
-       union xfs_btree_rec     nrec;   /* new record count */
+       union xfs_btree_bigkey  nkey;   /* new block key */
+       union xfs_btree_key     *lkey;
        int                     optr;   /* old key/record index */
        int                     ptr;    /* key/record index */
        int                     numrecs;/* number of records */
@@ -2942,11 +3235,13 @@ xfs_btree_insrec(
 #ifdef DEBUG
        int                     i;
 #endif
+       xfs_daddr_t             old_bn;
 
        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
-       XFS_BTREE_TRACE_ARGIPR(cur, level, *ptrp, recp);
+       XFS_BTREE_TRACE_ARGIPR(cur, level, *ptrp, &rec);
 
        ncur = NULL;
+       lkey = (union xfs_btree_key *)&nkey;
 
        /*
         * If we have an external root pointer, and we've made it to the
@@ -2969,15 +3264,13 @@ xfs_btree_insrec(
                return 0;
        }
 
-       /* Make a key out of the record data to be inserted, and save it. */
-       cur->bc_ops->init_key_from_rec(&key, recp);
-
        optr = ptr;
 
        XFS_BTREE_STATS_INC(cur, insrec);
 
        /* Get pointers to the btree buffer and block. */
        block = xfs_btree_get_block(cur, level, &bp);
+       old_bn = bp ? bp->b_bn : XFS_BUF_DADDR_NULL;
        numrecs = xfs_btree_get_numrecs(block);
 
 #ifdef DEBUG
@@ -2988,10 +3281,10 @@ xfs_btree_insrec(
        /* Check that the new entry is being inserted in the right place. */
        if (ptr <= numrecs) {
                if (level == 0) {
-                       ASSERT(cur->bc_ops->recs_inorder(cur, recp,
+                       ASSERT(cur->bc_ops->recs_inorder(cur, rec,
                                xfs_btree_rec_addr(cur, ptr, block)));
                } else {
-                       ASSERT(cur->bc_ops->keys_inorder(cur, &key,
+                       ASSERT(cur->bc_ops->keys_inorder(cur, key,
                                xfs_btree_key_addr(cur, ptr, block)));
                }
        }
@@ -3004,7 +3297,7 @@ xfs_btree_insrec(
        xfs_btree_set_ptr_null(cur, &nptr);
        if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
                error = xfs_btree_make_block_unfull(cur, level, numrecs,
-                                       &optr, &ptr, &nptr, &ncur, &nrec, stat);
+                                       &optr, &ptr, &nptr, &ncur, lkey, stat);
                if (error || *stat == 0)
                        goto error0;
        }
@@ -3054,7 +3347,7 @@ xfs_btree_insrec(
 #endif
 
                /* Now put the new data in, bump numrecs and log it. */
-               xfs_btree_copy_keys(cur, kp, &key, 1);
+               xfs_btree_copy_keys(cur, kp, key, 1);
                xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
                numrecs++;
                xfs_btree_set_numrecs(block, numrecs);
@@ -3075,7 +3368,7 @@ xfs_btree_insrec(
                xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
 
                /* Now put the new data in, bump numrecs and log it. */
-               xfs_btree_copy_recs(cur, rp, recp, 1);
+               xfs_btree_copy_recs(cur, rp, rec, 1);
                xfs_btree_set_numrecs(block, ++numrecs);
                xfs_btree_log_recs(cur, bp, ptr, numrecs);
 #ifdef DEBUG
@@ -3089,9 +3382,18 @@ xfs_btree_insrec(
        /* Log the new number of records in the btree header. */
        xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
 
-       /* If we inserted at the start of a block, update the parents' keys. */
-       if (optr == 1) {
-               error = xfs_btree_updkey(cur, &key, level + 1);
+       /*
+        * If we just inserted into a new tree block, we have to
+        * recalculate nkey here because nkey is out of date.
+        *
+        * Otherwise we're just updating an existing block (having shoved
+        * some records into the new tree block), so use the regular key
+        * update mechanism.
+        */
+       if (bp && bp->b_bn != old_bn) {
+               xfs_btree_get_keys(cur, block, lkey);
+       } else if (xfs_btree_needs_key_update(cur, optr)) {
+               error = xfs_btree_update_keys(cur, level);
                if (error)
                        goto error0;
        }
@@ -3101,7 +3403,7 @@ xfs_btree_insrec(
         * we are at the far right edge of the tree, update it.
         */
        if (xfs_btree_is_lastrec(cur, block, level)) {
-               cur->bc_ops->update_lastrec(cur, block, recp,
+               cur->bc_ops->update_lastrec(cur, block, rec,
                                            ptr, LASTREC_INSREC);
        }
 
@@ -3111,7 +3413,7 @@ xfs_btree_insrec(
         */
        *ptrp = nptr;
        if (!xfs_btree_ptr_is_null(cur, &nptr)) {
-               *recp = nrec;
+               xfs_btree_copy_keys(cur, key, lkey, 1);
                *curp = ncur;
        }
 
@@ -3142,14 +3444,20 @@ xfs_btree_insert(
        union xfs_btree_ptr     nptr;   /* new block number (split result) */
        struct xfs_btree_cur    *ncur;  /* new cursor (split result) */
        struct xfs_btree_cur    *pcur;  /* previous level's cursor */
+       union xfs_btree_bigkey  bkey;   /* key of block to insert */
+       union xfs_btree_key     *key;
        union xfs_btree_rec     rec;    /* record to insert */
 
        level = 0;
        ncur = NULL;
        pcur = cur;
+       key = (union xfs_btree_key *)&bkey;
 
        xfs_btree_set_ptr_null(cur, &nptr);
+
+       /* Make a key out of the record data to be inserted, and save it. */
        cur->bc_ops->init_rec_from_cur(cur, &rec);
+       cur->bc_ops->init_key_from_rec(key, &rec);
 
        /*
         * Loop going up the tree, starting at the leaf level.
@@ -3161,7 +3469,8 @@ xfs_btree_insert(
                 * Insert nrec/nptr into this level of the tree.
                 * Note if we fail, nptr will be null.
                 */
-               error = xfs_btree_insrec(pcur, level, &nptr, &rec, &ncur, &i);
+               error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
+                               &ncur, &i);
                if (error) {
                        if (pcur != cur)
                                xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
@@ -3385,8 +3694,6 @@ xfs_btree_delrec(
        struct xfs_buf          *bp;            /* buffer for block */
        int                     error;          /* error return value */
        int                     i;              /* loop counter */
-       union xfs_btree_key     key;            /* storage for keyp */
-       union xfs_btree_key     *keyp = &key;   /* passed to the next level */
        union xfs_btree_ptr     lptr;           /* left sibling block ptr */
        struct xfs_buf          *lbp;           /* left buffer pointer */
        struct xfs_btree_block  *left;          /* left btree block */
@@ -3457,13 +3764,6 @@ xfs_btree_delrec(
                        xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
                        xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
                }
-
-               /*
-                * If it's the first record in the block, we'll need to pass a
-                * key up to the next level (updkey).
-                */
-               if (ptr == 1)
-                       keyp = xfs_btree_key_addr(cur, 1, block);
        } else {
                /* It's a leaf. operate on records */
                if (ptr < numrecs) {
@@ -3472,16 +3772,6 @@ xfs_btree_delrec(
                                -1, numrecs - ptr);
                        xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
                }
-
-               /*
-                * If it's the first record in the block, we'll need a key
-                * structure to pass up to the next level (updkey).
-                */
-               if (ptr == 1) {
-                       cur->bc_ops->init_key_from_rec(&key,
-                                       xfs_btree_rec_addr(cur, 1, block));
-                       keyp = &key;
-               }
        }
 
        /*
@@ -3548,8 +3838,8 @@ xfs_btree_delrec(
         * If we deleted the leftmost entry in the block, update the
         * key values above us in the tree.
         */
-       if (ptr == 1) {
-               error = xfs_btree_updkey(cur, keyp, level + 1);
+       if (xfs_btree_needs_key_update(cur, ptr)) {
+               error = xfs_btree_update_keys(cur, level);
                if (error)
                        goto error0;
        }
@@ -3878,6 +4168,16 @@ xfs_btree_delrec(
        if (level > 0)
                cur->bc_ptrs[level]--;
 
+       /*
+        * We combined blocks, so we have to update the parent keys if the
+        * btree supports overlapped intervals.  However, bc_ptrs[level + 1]
+        * points to the old block so that the caller knows which record to
+        * delete.  Therefore, the caller must be savvy enough to call updkeys
+        * for us if we return stat == 2.  The other exit points from this
+        * function don't require deletions further up the tree, so they can
+        * call updkeys directly.
+        */
+
        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
        /* Return value means the next level up has something to do. */
        *stat = 2;
@@ -3903,6 +4203,7 @@ xfs_btree_delete(
        int                     error;  /* error return value */
        int                     level;
        int                     i;
+       bool                    joined = false;
 
        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
 
@@ -3916,6 +4217,18 @@ xfs_btree_delete(
                error = xfs_btree_delrec(cur, level, &i);
                if (error)
                        goto error0;
+               if (i == 2)
+                       joined = true;
+       }
+
+       /*
+        * If we combined blocks as part of deleting the record, delrec won't
+        * have updated the parent high keys so we have to do that here.
+        */
+       if (joined && (cur->bc_flags & XFS_BTREE_OVERLAPPING)) {
+               error = xfs_btree_updkeys_force(cur, 0);
+               if (error)
+                       goto error0;
        }
 
        if (i == 0) {
@@ -3978,6 +4291,81 @@ xfs_btree_get_rec(
        return 0;
 }
 
+/* Visit a block in a btree. */
+STATIC int
+xfs_btree_visit_block(
+       struct xfs_btree_cur            *cur,
+       int                             level,
+       xfs_btree_visit_blocks_fn       fn,
+       void                            *data)
+{
+       struct xfs_btree_block          *block;
+       struct xfs_buf                  *bp;
+       union xfs_btree_ptr             rptr;
+       int                             error;
+
+       /* do right sibling readahead */
+       xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
+       block = xfs_btree_get_block(cur, level, &bp);
+
+       /* process the block */
+       error = fn(cur, level, data);
+       if (error)
+               return error;
+
+       /* now read rh sibling block for next iteration */
+       xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
+       if (xfs_btree_ptr_is_null(cur, &rptr))
+               return -ENOENT;
+
+       return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
+}
+
+
+/* Visit every block in a btree. */
+int
+xfs_btree_visit_blocks(
+       struct xfs_btree_cur            *cur,
+       xfs_btree_visit_blocks_fn       fn,
+       void                            *data)
+{
+       union xfs_btree_ptr             lptr;
+       int                             level;
+       struct xfs_btree_block          *block = NULL;
+       int                             error = 0;
+
+       cur->bc_ops->init_ptr_from_cur(cur, &lptr);
+
+       /* for each level */
+       for (level = cur->bc_nlevels - 1; level >= 0; level--) {
+               /* grab the left hand block */
+               error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
+               if (error)
+                       return error;
+
+               /* readahead the left most block for the next level down */
+               if (level > 0) {
+                       union xfs_btree_ptr     *ptr;
+
+                       ptr = xfs_btree_ptr_addr(cur, 1, block);
+                       xfs_btree_readahead_ptr(cur, ptr, 1);
+
+                       /* save for the next iteration of the loop */
+                       lptr = *ptr;
+               }
+
+               /* for each buffer in the level */
+               do {
+                       error = xfs_btree_visit_block(cur, level, fn, data);
+               } while (!error);
+
+               if (error != -ENOENT)
+                       return error;
+       }
+
+       return 0;
+}
+
 /*
  * Change the owner of a btree.
  *
@@ -4002,26 +4390,27 @@ xfs_btree_get_rec(
  * just queue the modified buffer as delayed write buffer so the transaction
  * recovery completion writes the changes to disk.
  */
+struct xfs_btree_block_change_owner_info {
+       __uint64_t              new_owner;
+       struct list_head        *buffer_list;
+};
+
 static int
 xfs_btree_block_change_owner(
        struct xfs_btree_cur    *cur,
        int                     level,
-       __uint64_t              new_owner,
-       struct list_head        *buffer_list)
+       void                    *data)
 {
+       struct xfs_btree_block_change_owner_info        *bbcoi = data;
        struct xfs_btree_block  *block;
        struct xfs_buf          *bp;
-       union xfs_btree_ptr     rptr;
-
-       /* do right sibling readahead */
-       xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
 
        /* modify the owner */
        block = xfs_btree_get_block(cur, level, &bp);
        if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
-               block->bb_u.l.bb_owner = cpu_to_be64(new_owner);
+               block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
        else
-               block->bb_u.s.bb_owner = cpu_to_be32(new_owner);
+               block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
 
        /*
         * If the block is a root block hosted in an inode, we might not have a
@@ -4035,19 +4424,14 @@ xfs_btree_block_change_owner(
                        xfs_trans_ordered_buf(cur->bc_tp, bp);
                        xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
                } else {
-                       xfs_buf_delwri_queue(bp, buffer_list);
+                       xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
                }
        } else {
                ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
                ASSERT(level == cur->bc_nlevels - 1);
        }
 
-       /* now read rh sibling block for next iteration */
-       xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
-       if (xfs_btree_ptr_is_null(cur, &rptr))
-               return -ENOENT;
-
-       return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
+       return 0;
 }
 
 int
@@ -4056,43 +4440,13 @@ xfs_btree_change_owner(
        __uint64_t              new_owner,
        struct list_head        *buffer_list)
 {
-       union xfs_btree_ptr     lptr;
-       int                     level;
-       struct xfs_btree_block  *block = NULL;
-       int                     error = 0;
+       struct xfs_btree_block_change_owner_info        bbcoi;
 
-       cur->bc_ops->init_ptr_from_cur(cur, &lptr);
+       bbcoi.new_owner = new_owner;
+       bbcoi.buffer_list = buffer_list;
 
-       /* for each level */
-       for (level = cur->bc_nlevels - 1; level >= 0; level--) {
-               /* grab the left hand block */
-               error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
-               if (error)
-                       return error;
-
-               /* readahead the left most block for the next level down */
-               if (level > 0) {
-                       union xfs_btree_ptr     *ptr;
-
-                       ptr = xfs_btree_ptr_addr(cur, 1, block);
-                       xfs_btree_readahead_ptr(cur, ptr, 1);
-
-                       /* save for the next iteration of the loop */
-                       lptr = *ptr;
-               }
-
-               /* for each buffer in the level */
-               do {
-                       error = xfs_btree_block_change_owner(cur, level,
-                                                            new_owner,
-                                                            buffer_list);
-               } while (!error);
-
-               if (error != -ENOENT)
-                       return error;
-       }
-
-       return 0;
+       return xfs_btree_visit_blocks(cur, xfs_btree_block_change_owner,
+                       &bbcoi);
 }
 
 /**
@@ -4171,3 +4525,275 @@ xfs_btree_compute_maxlevels(
                maxblocks = (maxblocks + limits[1] - 1) / limits[1];
        return level;
 }
+
+/*
+ * Query a regular btree for all records overlapping a given interval.
+ * Start with a LE lookup of the key of low_rec and return all records
+ * until we find a record with a key greater than the key of high_rec.
+ */
+STATIC int
+xfs_btree_simple_query_range(
+       struct xfs_btree_cur            *cur,
+       union xfs_btree_key             *low_key,
+       union xfs_btree_key             *high_key,
+       xfs_btree_query_range_fn        fn,
+       void                            *priv)
+{
+       union xfs_btree_rec             *recp;
+       union xfs_btree_key             rec_key;
+       __int64_t                       diff;
+       int                             stat;
+       bool                            firstrec = true;
+       int                             error;
+
+       ASSERT(cur->bc_ops->init_high_key_from_rec);
+       ASSERT(cur->bc_ops->diff_two_keys);
+
+       /*
+        * Find the leftmost record.  The btree cursor must be set
+        * to the low record used to generate low_key.
+        */
+       stat = 0;
+       error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
+       if (error)
+               goto out;
+
+       /* Nothing?  See if there's anything to the right. */
+       if (!stat) {
+               error = xfs_btree_increment(cur, 0, &stat);
+               if (error)
+                       goto out;
+       }
+
+       while (stat) {
+               /* Find the record. */
+               error = xfs_btree_get_rec(cur, &recp, &stat);
+               if (error || !stat)
+                       break;
+
+               /* Skip if high_key(rec) < low_key. */
+               if (firstrec) {
+                       cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
+                       firstrec = false;
+                       diff = cur->bc_ops->diff_two_keys(cur, low_key,
+                                       &rec_key);
+                       if (diff > 0)
+                               goto advloop;
+               }
+
+               /* Stop if high_key < low_key(rec). */
+               cur->bc_ops->init_key_from_rec(&rec_key, recp);
+               diff = cur->bc_ops->diff_two_keys(cur, &rec_key, high_key);
+               if (diff > 0)
+                       break;
+
+               /* Callback */
+               error = fn(cur, recp, priv);
+               if (error < 0 || error == XFS_BTREE_QUERY_RANGE_ABORT)
+                       break;
+
+advloop:
+               /* Move on to the next record. */
+               error = xfs_btree_increment(cur, 0, &stat);
+               if (error)
+                       break;
+       }
+
+out:
+       return error;
+}
+
+/*
+ * Query an overlapped interval btree for all records overlapping a given
+ * interval.  This function roughly follows the algorithm given in
+ * "Interval Trees" of _Introduction to Algorithms_, which is section
+ * 14.3 in the 2nd and 3rd editions.
+ *
+ * First, generate keys for the low and high records passed in.
+ *
+ * For any leaf node, generate the high and low keys for the record.
+ * If the record keys overlap with the query low/high keys, pass the
+ * record to the function iterator.
+ *
+ * For any internal node, compare the low and high keys of each
+ * pointer against the query low/high keys.  If there's an overlap,
+ * follow the pointer.
+ *
+ * As an optimization, we stop scanning a block when we find a low key
+ * that is greater than the query's high key.
+ */
+STATIC int
+xfs_btree_overlapped_query_range(
+       struct xfs_btree_cur            *cur,
+       union xfs_btree_key             *low_key,
+       union xfs_btree_key             *high_key,
+       xfs_btree_query_range_fn        fn,
+       void                            *priv)
+{
+       union xfs_btree_ptr             ptr;
+       union xfs_btree_ptr             *pp;
+       union xfs_btree_key             rec_key;
+       union xfs_btree_key             rec_hkey;
+       union xfs_btree_key             *lkp;
+       union xfs_btree_key             *hkp;
+       union xfs_btree_rec             *recp;
+       struct xfs_btree_block          *block;
+       __int64_t                       ldiff;
+       __int64_t                       hdiff;
+       int                             level;
+       struct xfs_buf                  *bp;
+       int                             i;
+       int                             error;
+
+       /* Load the root of the btree. */
+       level = cur->bc_nlevels - 1;
+       cur->bc_ops->init_ptr_from_cur(cur, &ptr);
+       error = xfs_btree_lookup_get_block(cur, level, &ptr, &block);
+       if (error)
+               return error;
+       xfs_btree_get_block(cur, level, &bp);
+       trace_xfs_btree_overlapped_query_range(cur, level, bp);
+#ifdef DEBUG
+       error = xfs_btree_check_block(cur, block, level, bp);
+       if (error)
+               goto out;
+#endif
+       cur->bc_ptrs[level] = 1;
+
+       while (level < cur->bc_nlevels) {
+               block = xfs_btree_get_block(cur, level, &bp);
+
+               /* End of node, pop back towards the root. */
+               if (cur->bc_ptrs[level] > be16_to_cpu(block->bb_numrecs)) {
+pop_up:
+                       if (level < cur->bc_nlevels - 1)
+                               cur->bc_ptrs[level + 1]++;
+                       level++;
+                       continue;
+               }
+
+               if (level == 0) {
+                       /* Handle a leaf node. */
+                       recp = xfs_btree_rec_addr(cur, cur->bc_ptrs[0], block);
+
+                       cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
+                       ldiff = cur->bc_ops->diff_two_keys(cur, &rec_hkey,
+                                       low_key);
+
+                       cur->bc_ops->init_key_from_rec(&rec_key, recp);
+                       hdiff = cur->bc_ops->diff_two_keys(cur, high_key,
+                                       &rec_key);
+
+                       /*
+                        * If (record's high key >= query's low key) and
+                        *    (query's high key >= record's low key), then
+                        * this record overlaps the query range; callback.
+                        */
+                       if (ldiff >= 0 && hdiff >= 0) {
+                               error = fn(cur, recp, priv);
+                               if (error < 0 ||
+                                   error == XFS_BTREE_QUERY_RANGE_ABORT)
+                                       break;
+                       } else if (hdiff < 0) {
+                               /* Record is larger than high key; pop. */
+                               goto pop_up;
+                       }
+                       cur->bc_ptrs[level]++;
+                       continue;
+               }
+
+               /* Handle an internal node. */
+               lkp = xfs_btree_key_addr(cur, cur->bc_ptrs[level], block);
+               hkp = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level], block);
+               pp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[level], block);
+
+               ldiff = cur->bc_ops->diff_two_keys(cur, hkp, low_key);
+               hdiff = cur->bc_ops->diff_two_keys(cur, high_key, lkp);
+
+               /*
+                * If (pointer's high key >= query's low key) and
+                *    (query's high key >= pointer's low key), then
+                * this record overlaps the query range; follow pointer.
+                */
+               if (ldiff >= 0 && hdiff >= 0) {
+                       level--;
+                       error = xfs_btree_lookup_get_block(cur, level, pp,
+                                       &block);
+                       if (error)
+                               goto out;
+                       xfs_btree_get_block(cur, level, &bp);
+                       trace_xfs_btree_overlapped_query_range(cur, level, bp);
+#ifdef DEBUG
+                       error = xfs_btree_check_block(cur, block, level, bp);
+                       if (error)
+                               goto out;
+#endif
+                       cur->bc_ptrs[level] = 1;
+                       continue;
+               } else if (hdiff < 0) {
+                       /* The low key is larger than the upper range; pop. */
+                       goto pop_up;
+               }
+               cur->bc_ptrs[level]++;
+       }
+
+out:
+       /*
+        * If we don't end this function with the cursor pointing at a record
+        * block, a subsequent non-error cursor deletion will not release
+        * node-level buffers, causing a buffer leak.  This is quite possible
+        * with a zero-results range query, so release the buffers if we
+        * failed to return any results.
+        */
+       if (cur->bc_bufs[0] == NULL) {
+               for (i = 0; i < cur->bc_nlevels; i++) {
+                       if (cur->bc_bufs[i]) {
+                               xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
+                               cur->bc_bufs[i] = NULL;
+                               cur->bc_ptrs[i] = 0;
+                               cur->bc_ra[i] = 0;
+                       }
+               }
+       }
+
+       return error;
+}
+
+/*
+ * Query a btree for all records overlapping a given interval of keys.  The
+ * supplied function will be called with each record found; return one of the
+ * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
+ * code.  This function returns XFS_BTREE_QUERY_RANGE_ABORT, zero, or a
+ * negative error code.
+ */
+int
+xfs_btree_query_range(
+       struct xfs_btree_cur            *cur,
+       union xfs_btree_irec            *low_rec,
+       union xfs_btree_irec            *high_rec,
+       xfs_btree_query_range_fn        fn,
+       void                            *priv)
+{
+       union xfs_btree_rec             rec;
+       union xfs_btree_key             low_key;
+       union xfs_btree_key             high_key;
+
+       /* Find the keys of both ends of the interval. */
+       cur->bc_rec = *high_rec;
+       cur->bc_ops->init_rec_from_cur(cur, &rec);
+       cur->bc_ops->init_key_from_rec(&high_key, &rec);
+
+       cur->bc_rec = *low_rec;
+       cur->bc_ops->init_rec_from_cur(cur, &rec);
+       cur->bc_ops->init_key_from_rec(&low_key, &rec);
+
+       /* Enforce low key < high key. */
+       if (cur->bc_ops->diff_two_keys(cur, &low_key, &high_key) > 0)
+               return -EINVAL;
+
+       if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
+               return xfs_btree_simple_query_range(cur, &low_key,
+                               &high_key, fn, priv);
+       return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
+                       fn, priv);
+}