From: Dave Chinner <dchinner@xxxxxxxxxx>
Implement the generic btree operations needed to manipulate rmap
btree blocks. This is very similar to the per-ag freespace btree
implementation, and uses the AGFL for allocation and freeing of
blocks.
Adapt the rmap btree to store owner offsets within each rmap record,
and to handle the primary key being redefined as the tuple
[agblk, owner, offset]. The expansion of the primary key is crucial
to allowing multiple owners per extent. Unfortunately, doing so adds
the requirement that all rmap records for file extents (metadata
always has one owner) correspond to some bmbt entry somewhere.
[darrick.wong@xxxxxxxxxx: adapt the btree ops to deal with offsets]
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
---
fs/xfs/libxfs/xfs_btree.h | 1 +
fs/xfs/libxfs/xfs_rmap.c | 82 ++++++++++++++
fs/xfs/libxfs/xfs_rmap_btree.c | 237 +++++++++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_rmap_btree.h | 7 ++
4 files changed, 327 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 07fa27e..6443c74 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -212,6 +212,7 @@ typedef struct xfs_btree_cur
xfs_alloc_rec_incore_t a;
xfs_bmbt_irec_t b;
xfs_inobt_rec_incore_t i;
+ struct xfs_rmap_irec r;
} 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_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
index 3e17294..f6fe742 100644
--- a/fs/xfs/libxfs/xfs_rmap.c
+++ b/fs/xfs/libxfs/xfs_rmap.c
@@ -36,6 +36,88 @@
#include "xfs_error.h"
#include "xfs_extent_busy.h"
+/*
+ * Lookup the first record less than or equal to [bno, len, owner, offset]
+ * in the btree given by cur.
+ */
+int
+xfs_rmap_lookup_le(
+ struct xfs_btree_cur *cur,
+ xfs_agblock_t bno,
+ xfs_extlen_t len,
+ uint64_t owner,
+ uint64_t offset,
+ int *stat)
+{
+ cur->bc_rec.r.rm_startblock = bno;
+ cur->bc_rec.r.rm_blockcount = len;
+ cur->bc_rec.r.rm_owner = owner;
+ cur->bc_rec.r.rm_offset = offset;
+ return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
+}
+
+/*
+ * Lookup the record exactly matching [bno, len, owner, offset]
+ * in the btree given by cur.
+ */
+int
+xfs_rmap_lookup_eq(
+ struct xfs_btree_cur *cur,
+ xfs_agblock_t bno,
+ xfs_extlen_t len,
+ uint64_t owner,
+ uint64_t offset,
+ int *stat)
+{
+ cur->bc_rec.r.rm_startblock = bno;
+ cur->bc_rec.r.rm_blockcount = len;
+ cur->bc_rec.r.rm_owner = owner;
+ cur->bc_rec.r.rm_offset = offset;
+ return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
+}
+
+/*
+ * Update the record referred to by cur to the value given
+ * by [bno, len, owner, offset].
+ * This either works (return 0) or gets an EFSCORRUPTED error.
+ */
+STATIC int
+xfs_rmap_update(
+ struct xfs_btree_cur *cur,
+ struct xfs_rmap_irec *irec)
+{
+ union xfs_btree_rec rec;
+
+ rec.rmap.rm_startblock = cpu_to_be32(irec->rm_startblock);
+ rec.rmap.rm_blockcount = cpu_to_be32(irec->rm_blockcount);
+ rec.rmap.rm_owner = cpu_to_be64(irec->rm_owner);
+ rec.rmap.rm_offset = cpu_to_be64(irec->rm_offset);
+ return xfs_btree_update(cur, &rec);
+}
+
+/*
+ * Get the data from the pointed-to record.
+ */
+int
+xfs_rmap_get_rec(
+ struct xfs_btree_cur *cur,
+ struct xfs_rmap_irec *irec,
+ int *stat)
+{
+ union xfs_btree_rec *rec;
+ int error;
+
+ error = xfs_btree_get_rec(cur, &rec, stat);
+ if (error || !*stat)
+ return error;
+
+ irec->rm_startblock = be32_to_cpu(rec->rmap.rm_startblock);
+ irec->rm_blockcount = be32_to_cpu(rec->rmap.rm_blockcount);
+ irec->rm_owner = be64_to_cpu(rec->rmap.rm_owner);
+ irec->rm_offset = be64_to_cpu(rec->rmap.rm_offset);
+ return 0;
+}
+
int
xfs_rmap_free(
struct xfs_trans *tp,
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index 882e8e2..54dd118 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -34,6 +34,31 @@
#include "xfs_error.h"
#include "xfs_extent_busy.h"
+/*
+ * Reverse map btree.
+ *
+ * This is a per-ag tree used to track the owner(s) of a given extent. With
+ * reflink it is possible for there to be multiple owners, which is a departure
+ * from classic XFS. Owner records for data extents are inserted when the
+ * extent is mapped and removed when an extent is unmapped. Owner records for
+ * all other block types (i.e. metadata) are inserted when an extent is
+ * allocated and removed when an extent is freed. There can only be one owner
+ * of a metadata extent, usually an inode or some other metadata structure like
+ * an AG btree.
+ *
+ * The rmap btree is part of the free space management, so blocks for the tree
+ * are sourced from the agfl. Hence we need transaction reservation support for
+ * this tree so that the freelist is always large enough. This also impacts on
+ * the minimum space we need to leave free in the AG.
+ *
+ * The tree is ordered by [ag block, owner, offset]. This is a large key size,
+ * but it is the only way to enforce unique keys when a block can be owned by
+ * multiple files at any offset. There's no need to order/search by extent
+ * size for online updating/management of the tree. It is intended that most
+ * reverse lookups will be to find the owner(s) of a particular block, or to
+ * try to recover tree and file data from corrupt primary metadata.
+ */
+
static struct xfs_btree_cur *
xfs_rmapbt_dup_cursor(
struct xfs_btree_cur *cur)
@@ -42,6 +67,166 @@ xfs_rmapbt_dup_cursor(
cur->bc_private.a.agbp, cur->bc_private.a.agno);
}
+STATIC void
+xfs_rmapbt_set_root(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *ptr,
+ int inc)
+{
+ struct xfs_buf *agbp = cur->bc_private.a.agbp;
+ struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
+ xfs_agnumber_t seqno = be32_to_cpu(agf->agf_seqno);
+ int btnum = cur->bc_btnum;
+ struct xfs_perag *pag = xfs_perag_get(cur->bc_mp, seqno);
+
+ ASSERT(ptr->s != 0);
+
+ agf->agf_roots[btnum] = ptr->s;
+ be32_add_cpu(&agf->agf_levels[btnum], inc);
+ pag->pagf_levels[btnum] += inc;
+ xfs_perag_put(pag);
+
+ xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
+}
+
+STATIC int
+xfs_rmapbt_alloc_block(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *start,
+ union xfs_btree_ptr *new,
+ int *stat)
+{
+ int error;
+ xfs_agblock_t bno;
+
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
+
+ /* Allocate the new block from the freelist. If we can't, give up. */
+ error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
+ &bno, 1);
+ if (error) {
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
+ return error;
+ }
+
+ if (bno == NULLAGBLOCK) {
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+ *stat = 0;
+ return 0;
+ }
+
+ xfs_extent_busy_reuse(cur->bc_mp, cur->bc_private.a.agno, bno, 1, false);
+
+ xfs_trans_agbtree_delta(cur->bc_tp, 1);
+ new->s = cpu_to_be32(bno);
+
+ XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+ *stat = 1;
+ return 0;
+}
+
+STATIC int
+xfs_rmapbt_free_block(
+ struct xfs_btree_cur *cur,
+ struct xfs_buf *bp)
+{
+ struct xfs_buf *agbp = cur->bc_private.a.agbp;
+ struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
+ xfs_agblock_t bno;
+ int error;
+
+ bno = xfs_daddr_to_agbno(cur->bc_mp, XFS_BUF_ADDR(bp));
+ error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
+ if (error)
+ return error;
+
+ xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
+ XFS_EXTENT_BUSY_SKIP_DISCARD);
+ xfs_trans_agbtree_delta(cur->bc_tp, -1);
+
+ xfs_trans_binval(cur->bc_tp, bp);
+ return 0;
+}
+
+STATIC int
+xfs_rmapbt_get_minrecs(
+ struct xfs_btree_cur *cur,
+ int level)
+{
+ return cur->bc_mp->m_rmap_mnr[level != 0];
+}
+
+STATIC int
+xfs_rmapbt_get_maxrecs(
+ struct xfs_btree_cur *cur,
+ int level)
+{
+ return cur->bc_mp->m_rmap_mxr[level != 0];
+}
+
+STATIC void
+xfs_rmapbt_init_key_from_rec(
+ union xfs_btree_key *key,
+ union xfs_btree_rec *rec)
+{
+ key->rmap.rm_startblock = rec->rmap.rm_startblock;
+ key->rmap.rm_owner = rec->rmap.rm_owner;
+ key->rmap.rm_offset = rec->rmap.rm_offset;
+}
+
+STATIC void
+xfs_rmapbt_init_rec_from_key(
+ union xfs_btree_key *key,
+ union xfs_btree_rec *rec)
+{
+ rec->rmap.rm_startblock = key->rmap.rm_startblock;
+ rec->rmap.rm_owner = key->rmap.rm_owner;
+ rec->rmap.rm_offset = key->rmap.rm_offset;
+}
+
+STATIC void
+xfs_rmapbt_init_rec_from_cur(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_rec *rec)
+{
+ rec->rmap.rm_startblock = cpu_to_be32(cur->bc_rec.r.rm_startblock);
+ rec->rmap.rm_blockcount = cpu_to_be32(cur->bc_rec.r.rm_blockcount);
+ rec->rmap.rm_owner = cpu_to_be64(cur->bc_rec.r.rm_owner);
+ rec->rmap.rm_offset = cpu_to_be64(cur->bc_rec.r.rm_offset);
+}
+
+STATIC void
+xfs_rmapbt_init_ptr_from_cur(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_ptr *ptr)
+{
+ struct xfs_agf *agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
+
+ ASSERT(cur->bc_private.a.agno == be32_to_cpu(agf->agf_seqno));
+ ASSERT(agf->agf_roots[cur->bc_btnum] != 0);
+
+ ptr->s = agf->agf_roots[cur->bc_btnum];
+}
+
+STATIC __int64_t
+xfs_rmapbt_key_diff(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_key *key)
+{
+ struct xfs_rmap_irec *rec = &cur->bc_rec.r;
+ struct xfs_rmap_key *kp = &key->rmap;
+ __int64_t d;
+
+ d = (__int64_t)be32_to_cpu(kp->rm_startblock) - rec->rm_startblock;
+ if (d)
+ return d;
+ d = (__int64_t)be64_to_cpu(kp->rm_owner) - rec->rm_owner;
+ if (d)
+ return d;
+ d = (__int64_t)be64_to_cpu(kp->rm_offset) - rec->rm_offset;
+ return d;
+}
+
static bool
xfs_rmapbt_verify(
struct xfs_buf *bp)
@@ -116,12 +301,64 @@ const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
.verify_write = xfs_rmapbt_write_verify,
};
+#if defined(DEBUG) || defined(XFS_WARN)
+STATIC int
+xfs_rmapbt_keys_inorder(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_key *k1,
+ union xfs_btree_key *k2)
+{
+ if (be32_to_cpu(k1->rmap.rm_startblock) <
+ be32_to_cpu(k2->rmap.rm_startblock))
+ return 1;
+ if (be64_to_cpu(k1->rmap.rm_owner) <
+ be64_to_cpu(k2->rmap.rm_owner))
+ return 1;
+ if (be64_to_cpu(k1->rmap.rm_offset) <=
+ be64_to_cpu(k2->rmap.rm_offset))
+ return 1;
+ return 0;
+}
+
+STATIC int
+xfs_rmapbt_recs_inorder(
+ struct xfs_btree_cur *cur,
+ union xfs_btree_rec *r1,
+ union xfs_btree_rec *r2)
+{
+ if (be32_to_cpu(r1->rmap.rm_startblock) <
+ be32_to_cpu(r2->rmap.rm_startblock))
+ return 1;
+ if (be64_to_cpu(r1->rmap.rm_offset) <
+ be64_to_cpu(r2->rmap.rm_offset))
+ return 1;
+ if (be64_to_cpu(r1->rmap.rm_owner) <=
+ be64_to_cpu(r2->rmap.rm_owner))
+ return 1;
+ return 0;
+}
+#endif /* DEBUG */
+
static const struct xfs_btree_ops xfs_rmapbt_ops = {
.rec_len = sizeof(struct xfs_rmap_rec),
.key_len = sizeof(struct xfs_rmap_key),
.dup_cursor = xfs_rmapbt_dup_cursor,
+ .set_root = xfs_rmapbt_set_root,
+ .alloc_block = xfs_rmapbt_alloc_block,
+ .free_block = xfs_rmapbt_free_block,
+ .get_minrecs = xfs_rmapbt_get_minrecs,
+ .get_maxrecs = xfs_rmapbt_get_maxrecs,
+ .init_key_from_rec = xfs_rmapbt_init_key_from_rec,
+ .init_rec_from_key = xfs_rmapbt_init_rec_from_key,
+ .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,
+#if defined(DEBUG) || defined(XFS_WARN)
+ .keys_inorder = xfs_rmapbt_keys_inorder,
+ .recs_inorder = xfs_rmapbt_recs_inorder,
+#endif
};
/*
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
index 2e02362..a5c97f8 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.h
+++ b/fs/xfs/libxfs/xfs_rmap_btree.h
@@ -51,6 +51,13 @@ struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct xfs_mount *mp,
xfs_agnumber_t agno);
int xfs_rmapbt_maxrecs(struct xfs_mount *mp, int blocklen, int leaf);
+int xfs_rmap_lookup_le(struct xfs_btree_cur *cur, xfs_agblock_t bno,
+ xfs_extlen_t len, uint64_t owner, uint64_t offset, int *stat);
+int xfs_rmap_lookup_eq(struct xfs_btree_cur *cur, xfs_agblock_t bno,
+ xfs_extlen_t len, uint64_t owner, uint64_t offset, int *stat);
+int xfs_rmap_get_rec(struct xfs_btree_cur *cur, struct xfs_rmap_irec *irec,
+ int *stat);
+
int xfs_rmap_alloc(struct xfs_trans *tp, struct xfs_buf *agbp,
xfs_agnumber_t agno, xfs_agblock_t bno, xfs_extlen_t len,
struct xfs_owner_info *oinfo);
--
2.7.0
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