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[PATCH 033/119] xfs: support overlapping intervals in the rmap btree

To: david@xxxxxxxxxxxxx, darrick.wong@xxxxxxxxxx
Subject: [PATCH 033/119] xfs: support overlapping intervals in the rmap btree
From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
Date: Thu, 16 Jun 2016 18:21:24 -0700
Cc: linux-fsdevel@xxxxxxxxxxxxxxx, vishal.l.verma@xxxxxxxxx, xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <146612627129.12839.3827886950949809165.stgit@xxxxxxxxxxxxxxxx>
References: <146612627129.12839.3827886950949809165.stgit@xxxxxxxxxxxxxxxx>
User-agent: StGit/0.17.1-dirty
Now that the generic btree code supports overlapping intervals, plug
in the rmap btree to this functionality.  We will need it to find
potential left neighbors in xfs_rmap_{alloc,free} later in the patch
set.

v2: Fix bit manipulation bug when generating high key offset.
v3: Move unwritten bit to rm_offset.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_rmap_btree.c |   59 +++++++++++++++++++++++++++++++++++++++-
 fs/xfs/libxfs/xfs_rmap_btree.h |   10 +++++--
 2 files changed, 66 insertions(+), 3 deletions(-)


diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index c50c725..9adb930 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -181,6 +181,28 @@ xfs_rmapbt_init_key_from_rec(
 }
 
 STATIC void
+xfs_rmapbt_init_high_key_from_rec(
+       union xfs_btree_key     *key,
+       union xfs_btree_rec     *rec)
+{
+       __uint64_t              off;
+       int                     adj;
+
+       adj = be32_to_cpu(rec->rmap.rm_blockcount) - 1;
+
+       key->rmap.rm_startblock = rec->rmap.rm_startblock;
+       be32_add_cpu(&key->rmap.rm_startblock, adj);
+       key->rmap.rm_owner = rec->rmap.rm_owner;
+       key->rmap.rm_offset = rec->rmap.rm_offset;
+       if (XFS_RMAP_NON_INODE_OWNER(be64_to_cpu(rec->rmap.rm_owner)) ||
+           XFS_RMAP_IS_BMBT_BLOCK(be64_to_cpu(rec->rmap.rm_offset)))
+               return;
+       off = be64_to_cpu(key->rmap.rm_offset);
+       off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
+       key->rmap.rm_offset = cpu_to_be64(off);
+}
+
+STATIC void
 xfs_rmapbt_init_rec_from_cur(
        struct xfs_btree_cur    *cur,
        union xfs_btree_rec     *rec)
@@ -235,6 +257,38 @@ xfs_rmapbt_key_diff(
        return 0;
 }
 
+STATIC __int64_t
+xfs_rmapbt_diff_two_keys(
+       struct xfs_btree_cur    *cur,
+       union xfs_btree_key     *k1,
+       union xfs_btree_key     *k2)
+{
+       struct xfs_rmap_key     *kp1 = &k1->rmap;
+       struct xfs_rmap_key     *kp2 = &k2->rmap;
+       __int64_t               d;
+       __u64                   x, y;
+
+       d = (__int64_t)be32_to_cpu(kp2->rm_startblock) -
+                      be32_to_cpu(kp1->rm_startblock);
+       if (d)
+               return d;
+
+       x = be64_to_cpu(kp2->rm_owner);
+       y = be64_to_cpu(kp1->rm_owner);
+       if (x > y)
+               return 1;
+       else if (y > x)
+               return -1;
+
+       x = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
+       y = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
+       if (x > y)
+               return 1;
+       else if (y > x)
+               return -1;
+       return 0;
+}
+
 static bool
 xfs_rmapbt_verify(
        struct xfs_buf          *bp)
@@ -350,6 +404,7 @@ xfs_rmapbt_recs_inorder(
 static const struct xfs_btree_ops xfs_rmapbt_ops = {
        .rec_len                = sizeof(struct xfs_rmap_rec),
        .key_len                = sizeof(struct xfs_rmap_key),
+       .flags                  = XFS_BTREE_OPS_OVERLAPPING,
 
        .dup_cursor             = xfs_rmapbt_dup_cursor,
        .set_root               = xfs_rmapbt_set_root,
@@ -358,10 +413,12 @@ static const struct xfs_btree_ops xfs_rmapbt_ops = {
        .get_minrecs            = xfs_rmapbt_get_minrecs,
        .get_maxrecs            = xfs_rmapbt_get_maxrecs,
        .init_key_from_rec      = xfs_rmapbt_init_key_from_rec,
+       .init_high_key_from_rec = xfs_rmapbt_init_high_key_from_rec,
        .init_rec_from_cur      = xfs_rmapbt_init_rec_from_cur,
        .init_ptr_from_cur      = xfs_rmapbt_init_ptr_from_cur,
        .key_diff               = xfs_rmapbt_key_diff,
        .buf_ops                = &xfs_rmapbt_buf_ops,
+       .diff_two_keys          = xfs_rmapbt_diff_two_keys,
 #if defined(DEBUG) || defined(XFS_WARN)
        .keys_inorder           = xfs_rmapbt_keys_inorder,
        .recs_inorder           = xfs_rmapbt_recs_inorder,
@@ -410,7 +467,7 @@ xfs_rmapbt_maxrecs(
        if (leaf)
                return blocklen / sizeof(struct xfs_rmap_rec);
        return blocklen /
-               (sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
+               (2 * sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
 }
 
 /* Compute the maximum height of an rmap btree. */
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
index 17fa383..796071c 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.h
+++ b/fs/xfs/libxfs/xfs_rmap_btree.h
@@ -38,12 +38,18 @@ struct xfs_mount;
 #define XFS_RMAP_KEY_ADDR(block, index) \
        ((struct xfs_rmap_key *) \
                ((char *)(block) + XFS_RMAP_BLOCK_LEN + \
-                ((index) - 1) * sizeof(struct xfs_rmap_key)))
+                ((index) - 1) * 2 * sizeof(struct xfs_rmap_key)))
+
+#define XFS_RMAP_HIGH_KEY_ADDR(block, index) \
+       ((struct xfs_rmap_key *) \
+               ((char *)(block) + XFS_RMAP_BLOCK_LEN + \
+                sizeof(struct xfs_rmap_key) + \
+                ((index) - 1) * 2 * sizeof(struct xfs_rmap_key)))
 
 #define XFS_RMAP_PTR_ADDR(block, index, maxrecs) \
        ((xfs_rmap_ptr_t *) \
                ((char *)(block) + XFS_RMAP_BLOCK_LEN + \
-                (maxrecs) * sizeof(struct xfs_rmap_key) + \
+                (maxrecs) * 2 * sizeof(struct xfs_rmap_key) + \
                 ((index) - 1) * sizeof(xfs_rmap_ptr_t)))
 
 struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct xfs_mount *mp,

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