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

Darrick J. Wong
2015-07-29T22:33:45Z

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@oracle.com>
---
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. */