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[PATCH 05/24] xfs: define the on-disk refcount btree format

To: david@xxxxxxxxxxxxx, darrick.wong@xxxxxxxxxx
Subject: [PATCH 05/24] xfs: define the on-disk refcount btree format
From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
Date: Wed, 29 Jul 2015 15:33:30 -0700
Cc: xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <20150729223258.17414.91354.stgit@xxxxxxxxxxxxxxxx>
References: <20150729223258.17414.91354.stgit@xxxxxxxxxxxxxxxx>
User-agent: StGit/0.17.1-dirty
Start constructing the refcount btree implementation by establishing
the on-disk format and everything needed to read, write, and
manipulate the refcount btree blocks.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 fs/xfs/Makefile                    |    1 
 fs/xfs/libxfs/xfs_btree.c          |    3 +
 fs/xfs/libxfs/xfs_btree.h          |    3 +
 fs/xfs/libxfs/xfs_format.h         |   32 ++++++
 fs/xfs/libxfs/xfs_refcount_btree.c |  192 ++++++++++++++++++++++++++++++++++++
 fs/xfs/libxfs/xfs_refcount_btree.h |   65 ++++++++++++
 fs/xfs/libxfs/xfs_sb.c             |    9 ++
 fs/xfs/libxfs/xfs_shared.h         |    2 
 fs/xfs/xfs_mount.h                 |    2 
 9 files changed, 309 insertions(+)
 create mode 100644 fs/xfs/libxfs/xfs_refcount_btree.c
 create mode 100644 fs/xfs/libxfs/xfs_refcount_btree.h


diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index e338595..f3f7098 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -52,6 +52,7 @@ xfs-y                         += $(addprefix libxfs/, \
                                   xfs_log_rlimit.o \
                                   xfs_rmap.o \
                                   xfs_rmap_btree.o \
+                                  xfs_refcount_btree.o \
                                   xfs_sb.o \
                                   xfs_symlink_remote.o \
                                   xfs_trans_resv.o \
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 51b56c5..708f938 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -1118,6 +1118,9 @@ xfs_btree_set_refs(
        case XFS_BTNUM_RMAP:
                xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
                break;
+       case XFS_BTNUM_REFC:
+               xfs_buf_set_ref(bp, XFS_REFC_BTREE_REF);
+               break;
        default:
                ASSERT(0);
        }
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index b747c86..7a71292 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -43,6 +43,7 @@ union xfs_btree_key {
        xfs_alloc_key_t                 alloc;
        struct xfs_inobt_key            inobt;
        struct xfs_rmap_key             rmap;
+       struct xfs_refcount_key         refc;
 };
 
 union xfs_btree_rec {
@@ -51,6 +52,7 @@ union xfs_btree_rec {
        struct xfs_alloc_rec            alloc;
        struct xfs_inobt_rec            inobt;
        struct xfs_rmap_rec             rmap;
+       struct xfs_refcount_rec         refc;
 };
 
 /*
@@ -208,6 +210,7 @@ typedef struct xfs_btree_cur
                xfs_bmbt_irec_t         b;
                xfs_inobt_rec_incore_t  i;
                struct xfs_rmap_irec    r;
+               struct xfs_refcount_irec        rc;
        }               bc_rec;         /* current insert/search record value */
        struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
        int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index b1ad07d..71efa26 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1367,6 +1367,38 @@ typedef __be32 xfs_rmap_ptr_t;
 
 unsigned int XFS_REFC_BLOCK(struct xfs_mount *mp);
 
+/*
+ * Data record/key structure
+ *
+ * Each record associates a range of physical blocks (starting at
+ * rc_startblock and ending rc_blockcount blocks later) with a
+ * reference count (rc_refcount).  A record is only stored in the
+ * btree if the refcount is > 2.  An entry in the free block btree
+ * means that the refcount is 0, and no entries anywhere means that
+ * the refcount is 1, as was true in XFS before reflinking.
+ */
+struct xfs_refcount_rec {
+       __be32          rc_startblock;  /* starting block number */
+       __be32          rc_blockcount;  /* count of blocks */
+       __be32          rc_refcount;    /* number of inodes linked here */
+};
+
+struct xfs_refcount_key {
+       __be32          rc_startblock;  /* starting block number */
+};
+
+struct xfs_refcount_irec {
+       xfs_agblock_t   rc_startblock;  /* starting block number */
+       xfs_extlen_t    rc_blockcount;  /* count of free blocks */
+       xfs_nlink_t     rc_refcount;    /* number of inodes linked here */
+};
+
+#define MAXREFCOUNT    ((xfs_nlink_t)~0U)
+#define MAXREFCEXTLEN  ((xfs_extlen_t)~0U)
+
+/* btree pointer type */
+typedef __be32 xfs_refcount_ptr_t;
+
 
 /*
  * BMAP Btree format definitions
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c 
b/fs/xfs/libxfs/xfs_refcount_btree.c
new file mode 100644
index 0000000..cebafb0
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2015 Oracle.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_btree.h"
+#include "xfs_bmap.h"
+#include "xfs_refcount_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_cksum.h"
+#include "xfs_trans.h"
+#include "xfs_bit.h"
+
+static struct xfs_btree_cur *
+xfs_refcountbt_dup_cursor(
+       struct xfs_btree_cur    *cur)
+{
+       return xfs_refcountbt_init_cursor(cur->bc_mp, cur->bc_tp,
+                       cur->bc_private.a.agbp, cur->bc_private.a.agno,
+                       cur->bc_private.a.flist);
+}
+
+STATIC bool
+xfs_refcountbt_verify(
+       struct xfs_buf          *bp)
+{
+       struct xfs_mount        *mp = bp->b_target->bt_mount;
+       struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
+       struct xfs_perag        *pag = bp->b_pag;
+       unsigned int            level;
+
+       if (block->bb_magic != cpu_to_be32(XFS_REFC_CRC_MAGIC))
+               return false;
+
+       if (!xfs_sb_version_hasreflink(&mp->m_sb))
+               return false;
+       if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_uuid))
+               return false;
+       if (block->bb_u.s.bb_blkno != cpu_to_be64(bp->b_bn))
+               return false;
+       if (pag &&
+           be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
+               return false;
+
+       level = be16_to_cpu(block->bb_level);
+       if (pag && pag->pagf_init) {
+               if (level >= pag->pagf_refcount_level)
+                       return false;
+       } else if (level >= mp->m_ag_maxlevels)
+               return false;
+
+       /* numrecs verification */
+       if (be16_to_cpu(block->bb_numrecs) > mp->m_refc_mxr[level != 0])
+               return false;
+
+       /* sibling pointer verification */
+       if (!block->bb_u.s.bb_leftsib ||
+           (be32_to_cpu(block->bb_u.s.bb_leftsib) >= mp->m_sb.sb_agblocks &&
+            block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK)))
+               return false;
+       if (!block->bb_u.s.bb_rightsib ||
+           (be32_to_cpu(block->bb_u.s.bb_rightsib) >= mp->m_sb.sb_agblocks &&
+            block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK)))
+               return false;
+
+       return true;
+}
+
+STATIC void
+xfs_refcountbt_read_verify(
+       struct xfs_buf  *bp)
+{
+       if (!xfs_btree_sblock_verify_crc(bp))
+               xfs_buf_ioerror(bp, -EFSBADCRC);
+       else if (!xfs_refcountbt_verify(bp))
+               xfs_buf_ioerror(bp, -EFSCORRUPTED);
+
+       if (bp->b_error) {
+               trace_xfs_btree_corrupt(bp, _RET_IP_);
+               xfs_verifier_error(bp);
+       }
+}
+
+STATIC void
+xfs_refcountbt_write_verify(
+       struct xfs_buf  *bp)
+{
+       if (!xfs_refcountbt_verify(bp)) {
+               trace_xfs_btree_corrupt(bp, _RET_IP_);
+               xfs_buf_ioerror(bp, -EFSCORRUPTED);
+               xfs_verifier_error(bp);
+               return;
+       }
+       xfs_btree_sblock_calc_crc(bp);
+
+}
+
+const struct xfs_buf_ops xfs_refcountbt_buf_ops = {
+       .verify_read            = xfs_refcountbt_read_verify,
+       .verify_write           = xfs_refcountbt_write_verify,
+};
+
+static const struct xfs_btree_ops xfs_refcountbt_ops = {
+       .rec_len                = sizeof(struct xfs_refcount_rec),
+       .key_len                = sizeof(struct xfs_refcount_key),
+
+       .dup_cursor             = xfs_refcountbt_dup_cursor,
+       .buf_ops                = &xfs_refcountbt_buf_ops,
+};
+
+/**
+ * xfs_refcountbt_init_cursor() -- Allocate a new refcount btree cursor.
+ *
+ * @mp: XFS mount object
+ * @tp: XFS transaction
+ * @agbp: Buffer containing the AGF
+ * @agno: AG number
+ */
+struct xfs_btree_cur *
+xfs_refcountbt_init_cursor(
+       struct xfs_mount        *mp,
+       struct xfs_trans        *tp,
+       struct xfs_buf          *agbp,
+       xfs_agnumber_t          agno,
+       struct xfs_bmap_free    *flist)
+{
+       struct xfs_agf          *agf = XFS_BUF_TO_AGF(agbp);
+       struct xfs_btree_cur    *cur;
+
+       ASSERT(agno != NULLAGNUMBER);
+       ASSERT(agno < mp->m_sb.sb_agcount);
+       cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP);
+
+       cur->bc_tp = tp;
+       cur->bc_mp = mp;
+       cur->bc_btnum = XFS_BTNUM_REFC;
+       cur->bc_blocklog = mp->m_sb.sb_blocklog;
+       cur->bc_ops = &xfs_refcountbt_ops;
+
+       cur->bc_nlevels = be32_to_cpu(agf->agf_refcount_level);
+
+       cur->bc_private.a.agbp = agbp;
+       cur->bc_private.a.agno = agno;
+       cur->bc_private.a.flist = flist;
+       cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
+
+       return cur;
+}
+
+/**
+ * xfs_refcountbt_maxrecs() -- Calculate number of records in a refcount
+ *                            btree block.
+ * @mp: XFS mount object
+ * @blocklen: Length of block, in bytes.
+ * @leaf: true if this is a leaf btree block, false otherwise
+ */
+int
+xfs_refcountbt_maxrecs(
+       struct xfs_mount        *mp,
+       int                     blocklen,
+       bool                    leaf)
+{
+       blocklen -= XFS_REFCOUNT_BLOCK_LEN;
+
+       if (leaf)
+               return blocklen / sizeof(struct xfs_refcount_rec);
+       return blocklen / (sizeof(struct xfs_refcount_key) +
+                          sizeof(xfs_refcount_ptr_t));
+}
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.h 
b/fs/xfs/libxfs/xfs_refcount_btree.h
new file mode 100644
index 0000000..aadb279
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_refcount_btree.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2000,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2015 Oracle.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef __XFS_REFCOUNT_BTREE_H__
+#define        __XFS_REFCOUNT_BTREE_H__
+
+/*
+ * Freespace on-disk structures
+ */
+
+struct xfs_buf;
+struct xfs_btree_cur;
+struct xfs_mount;
+
+/*
+ * Btree block header size depends on a superblock flag.
+ */
+#define XFS_REFCOUNT_BLOCK_LEN XFS_BTREE_SBLOCK_CRC_LEN
+
+/*
+ * Record, key, and pointer address macros for btree blocks.
+ *
+ * (note that some of these may appear unused, but they are used in userspace)
+ */
+#define XFS_REFCOUNT_REC_ADDR(block, index) \
+       ((struct xfs_refcount_rec *) \
+               ((char *)(block) + \
+                XFS_REFCOUNT_BLOCK_LEN + \
+                (((index) - 1) * sizeof(struct xfs_refcount_rec))))
+
+#define XFS_REFCOUNT_KEY_ADDR(block, index) \
+       ((struct xfs_refcount_key *) \
+               ((char *)(block) + \
+                XFS_REFCOUNT_BLOCK_LEN + \
+                ((index) - 1) * sizeof(struct xfs_refcount_key)))
+
+#define XFS_REFCOUNT_PTR_ADDR(block, index, maxrecs) \
+       ((xfs_refcount_ptr_t *) \
+               ((char *)(block) + \
+                XFS_REFCOUNT_BLOCK_LEN + \
+                (maxrecs) * sizeof(struct xfs_refcount_key) + \
+                ((index) - 1) * sizeof(xfs_refcount_ptr_t)))
+
+extern struct xfs_btree_cur *xfs_refcountbt_init_cursor(struct xfs_mount *mp,
+               struct xfs_trans *tp, struct xfs_buf *agbp, xfs_agnumber_t agno,
+               struct xfs_bmap_free *flist);
+extern int xfs_refcountbt_maxrecs(struct xfs_mount *mp, int blocklen,
+               bool leaf);
+
+#endif /* __XFS_REFCOUNT_BTREE_H__ */
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index db5a19d3..a7dcbe0 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -36,6 +36,8 @@
 #include "xfs_alloc_btree.h"
 #include "xfs_ialloc_btree.h"
 #include "xfs_rmap_btree.h"
+#include "xfs_bmap.h"
+#include "xfs_refcount_btree.h"
 
 /*
  * Physical superblock buffer manipulations. Shared with libxfs in userspace.
@@ -717,6 +719,13 @@ xfs_sb_mount_common(
        mp->m_rmap_mnr[0] = mp->m_rmap_mxr[0] / 2;
        mp->m_rmap_mnr[1] = mp->m_rmap_mxr[1] / 2;
 
+       mp->m_refc_mxr[0] = xfs_refcountbt_maxrecs(mp, sbp->sb_blocksize,
+                       true);
+       mp->m_refc_mxr[1] = xfs_refcountbt_maxrecs(mp, sbp->sb_blocksize,
+                       false);
+       mp->m_refc_mnr[0] = mp->m_refc_mxr[0] / 2;
+       mp->m_refc_mnr[1] = mp->m_refc_mxr[1] / 2;
+
        mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
        mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
                                        sbp->sb_inopblock);
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index 88efbb4..77d1220 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -39,6 +39,7 @@ extern const struct xfs_buf_ops xfs_agf_buf_ops;
 extern const struct xfs_buf_ops xfs_agfl_buf_ops;
 extern const struct xfs_buf_ops xfs_allocbt_buf_ops;
 extern const struct xfs_buf_ops xfs_rmapbt_buf_ops;
+extern const struct xfs_buf_ops xfs_refcountbt_buf_ops;
 extern const struct xfs_buf_ops xfs_attr3_leaf_buf_ops;
 extern const struct xfs_buf_ops xfs_attr3_rmt_buf_ops;
 extern const struct xfs_buf_ops xfs_bmbt_buf_ops;
@@ -216,6 +217,7 @@ int xfs_log_calc_minimum_size(struct xfs_mount *);
 #define        XFS_INO_REF             2
 #define        XFS_ATTR_BTREE_REF      1
 #define        XFS_DQUOT_REF           1
+#define        XFS_REFC_BTREE_REF      1
 
 /*
  * Flags for xfs_trans_ichgtime().
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 4b286cc..aba42d7 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -92,6 +92,8 @@ typedef struct xfs_mount {
        uint                    m_inobt_mnr[2]; /* min inobt btree records */
        uint                    m_rmap_mxr[2];  /* max rmap btree records */
        uint                    m_rmap_mnr[2];  /* min rmap btree records */
+       uint                    m_refc_mxr[2];  /* max refc btree records */
+       uint                    m_refc_mnr[2];  /* min refc btree records */
        uint                    m_ag_maxlevels; /* XFS_AG_MAXLEVELS */
        uint                    m_bm_maxlevels[2]; /* XFS_BM_MAXLEVELS */
        uint                    m_in_maxlevels; /* max inobt btree levels. */

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