[PATCH 22/56] xfs: wire up a new metafile type for the realtime rmap

Darrick J. Wong
2025-02-06T22:40:51Z

Source kernel commit: f33659e8a114e2c17108227d30a2bdf398e39bdb

Plumb in the pieces we need to embed the root of the realtime rmap btree
in an inode's data fork, complete with new metafile type and on-disk
interpretation functions.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
libxfs/xfs_format.h | 8 +
libxfs/xfs_inode_fork.c | 6 +
libxfs/xfs_ondisk.h | 1
libxfs/xfs_rtrmap_btree.c | 251 +++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_rtrmap_btree.h | 112 ++++++++++++++++++++
5 files changed, 375 insertions(+), 3 deletions(-)

diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
index f32c9fda5a195f..fba4e59aded4a0 100644
--- a/libxfs/xfs_format.h
+++ b/libxfs/xfs_format.h
@@ -1736,6 +1736,14 @@ typedef __be32 xfs_rmap_ptr_t;
*/
#define XFS_RTRMAP_CRC_MAGIC 0x4d415052 /* 'MAPR' */

+/*
+ * rtrmap root header, on-disk form only.
+ */
+struct xfs_rtrmap_root {
+ __be16 bb_level; /* 0 is a leaf */
+ __be16 bb_numrecs; /* current # of data records */
+};
+
/* inode-based btree pointer type */
typedef __be64 xfs_rtrmap_ptr_t;

diff --git a/libxfs/xfs_inode_fork.c b/libxfs/xfs_inode_fork.c
index 7c481d159cce15..e4f866969bf1b6 100644
--- a/libxfs/xfs_inode_fork.c
+++ b/libxfs/xfs_inode_fork.c
@@ -25,6 +25,7 @@
#include "xfs_errortag.h"
#include "xfs_health.h"
#include "xfs_symlink_remote.h"
+#include "xfs_rtrmap_btree.h"

struct kmem_cache *xfs_ifork_cache;

@@ -268,8 +269,7 @@ xfs_iformat_data_fork(
case XFS_DINODE_FMT_META_BTREE:
switch (ip->i_metatype) {
case XFS_METAFILE_RTRMAP:
- ASSERT(0); /* to be implemented later */
- return -EFSCORRUPTED;
+ return xfs_iformat_rtrmap(ip, dip);
default:
break;
}
@@ -616,7 +616,7 @@ xfs_iflush_fork(

switch (ip->i_metatype) {
case XFS_METAFILE_RTRMAP:
- ASSERT(0); /* to be implemented later */
+ xfs_iflush_rtrmap(ip, dip);
break;
default:
ASSERT(0);
diff --git a/libxfs/xfs_ondisk.h b/libxfs/xfs_ondisk.h
index 2c50877a1a2f0b..07e2f5fb3a94ae 100644
--- a/libxfs/xfs_ondisk.h
+++ b/libxfs/xfs_ondisk.h
@@ -84,6 +84,7 @@ xfs_check_ondisk_structs(void)
XFS_CHECK_STRUCT_SIZE(union xfs_suminfo_raw, 4);
XFS_CHECK_STRUCT_SIZE(struct xfs_rtbuf_blkinfo, 48);
XFS_CHECK_STRUCT_SIZE(xfs_rtrmap_ptr_t, 8);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_rtrmap_root, 4);

/*
* m68k has problems with struct xfs_attr_leaf_name_remote, but we pad
diff --git a/libxfs/xfs_rtrmap_btree.c b/libxfs/xfs_rtrmap_btree.c
index 08d1e75f190854..39fd9a0ab986e6 100644
--- a/libxfs/xfs_rtrmap_btree.c
+++ b/libxfs/xfs_rtrmap_btree.c
@@ -75,6 +75,39 @@ xfs_rtrmapbt_get_maxrecs(
return cur->bc_mp->m_rtrmap_mxr[level != 0];
}

+/* Calculate number of records in the ondisk realtime rmap btree inode root. */
+unsigned int
+xfs_rtrmapbt_droot_maxrecs(
+ unsigned int blocklen,
+ bool leaf)
+{
+ blocklen -= sizeof(struct xfs_rtrmap_root);
+
+ if (leaf)
+ return blocklen / sizeof(struct xfs_rmap_rec);
+ return blocklen / (2 * sizeof(struct xfs_rmap_key) +
+ sizeof(xfs_rtrmap_ptr_t));
+}
+
+/*
+ * Get the maximum records we could store in the on-disk format.
+ *
+ * For non-root nodes this is equivalent to xfs_rtrmapbt_get_maxrecs, but
+ * for the root node this checks the available space in the dinode fork
+ * so that we can resize the in-memory buffer to match it. After a
+ * resize to the maximum size this function returns the same value
+ * as xfs_rtrmapbt_get_maxrecs for the root node, too.
+ */
+STATIC int
+xfs_rtrmapbt_get_dmaxrecs(
+ struct xfs_btree_cur *cur,
+ int level)
+{
+ if (level != cur->bc_nlevels - 1)
+ return cur->bc_mp->m_rtrmap_mxr[level != 0];
+ return xfs_rtrmapbt_droot_maxrecs(cur->bc_ino.forksize, level == 0);
+}
+
/*
* Convert the ondisk record's offset field into the ondisk key's offset field.
* Fork and bmbt are significant parts of the rmap record key, but written
@@ -367,6 +400,87 @@ xfs_rtrmapbt_keys_contiguous(
be32_to_cpu(key2->rmap.rm_startblock));
}

+static inline void
+xfs_rtrmapbt_move_ptrs(
+ struct xfs_mount *mp,
+ struct xfs_btree_block *broot,
+ short old_size,
+ size_t new_size,
+ unsigned int numrecs)
+{
+ void *dptr;
+ void *sptr;
+
+ sptr = xfs_rtrmap_broot_ptr_addr(mp, broot, 1, old_size);
+ dptr = xfs_rtrmap_broot_ptr_addr(mp, broot, 1, new_size);
+ memmove(dptr, sptr, numrecs * sizeof(xfs_rtrmap_ptr_t));
+}
+
+static struct xfs_btree_block *
+xfs_rtrmapbt_broot_realloc(
+ struct xfs_btree_cur *cur,
+ unsigned int new_numrecs)
+{
+ struct xfs_mount *mp = cur->bc_mp;
+ struct xfs_ifork *ifp = xfs_btree_ifork_ptr(cur);
+ struct xfs_btree_block *broot;
+ unsigned int new_size;
+ unsigned int old_size = ifp->if_broot_bytes;
+ const unsigned int level = cur->bc_nlevels - 1;
+
+ new_size = xfs_rtrmap_broot_space_calc(mp, level, new_numrecs);
+
+ /* Handle the nop case quietly. */
+ if (new_size == old_size)
+ return ifp->if_broot;
+
+ if (new_size > old_size) {
+ unsigned int old_numrecs;
+
+ /*
+ * If there wasn't any memory allocated before, just allocate
+ * it now and get out.
+ */
+ if (old_size == 0)
+ return xfs_broot_realloc(ifp, new_size);
+
+ /*
+ * If there is already an existing if_broot, then we need to
+ * realloc it and possibly move the node block pointers because
+ * those are not butted up against the btree block header.
+ */
+ old_numrecs = xfs_rtrmapbt_maxrecs(mp, old_size, level == 0);
+ broot = xfs_broot_realloc(ifp, new_size);
+ if (level > 0)
+ xfs_rtrmapbt_move_ptrs(mp, broot, old_size, new_size,
+ old_numrecs);
+ goto out_broot;
+ }
+
+ /*
+ * We're reducing numrecs. If we're going all the way to zero, just
+ * free the block.
+ */
+ ASSERT(ifp->if_broot != NULL && old_size > 0);
+ if (new_size == 0)
+ return xfs_broot_realloc(ifp, 0);
+
+ /*
+ * Shrink the btree root by possibly moving the rtrmapbt pointers,
+ * since they are not butted up against the btree block header. Then
+ * reallocate broot.
+ */
+ if (level > 0)
+ xfs_rtrmapbt_move_ptrs(mp, ifp->if_broot, old_size, new_size,
+ new_numrecs);
+ broot = xfs_broot_realloc(ifp, new_size);
+
+out_broot:
+ ASSERT(xfs_rtrmap_droot_space(broot) <=
+ xfs_inode_fork_size(cur->bc_ino.ip, cur->bc_ino.whichfork));
+ return broot;
+}
+
const struct xfs_btree_ops xfs_rtrmapbt_ops = {
.name = "rtrmap",
.type = XFS_BTREE_TYPE_INODE,
@@ -386,6 +500,7 @@ const struct xfs_btree_ops xfs_rtrmapbt_ops = {
.free_block = xfs_btree_free_metafile_block,
.get_minrecs = xfs_rtrmapbt_get_minrecs,
.get_maxrecs = xfs_rtrmapbt_get_maxrecs,
+ .get_dmaxrecs = xfs_rtrmapbt_get_dmaxrecs,
.init_key_from_rec = xfs_rtrmapbt_init_key_from_rec,
.init_high_key_from_rec = xfs_rtrmapbt_init_high_key_from_rec,
.init_rec_from_cur = xfs_rtrmapbt_init_rec_from_cur,
@@ -396,6 +511,7 @@ const struct xfs_btree_ops xfs_rtrmapbt_ops = {
.keys_inorder = xfs_rtrmapbt_keys_inorder,
.recs_inorder = xfs_rtrmapbt_recs_inorder,
.keys_contiguous = xfs_rtrmapbt_keys_contiguous,
+ .broot_realloc = xfs_rtrmapbt_broot_realloc,
};

/* Allocate a new rt rmap btree cursor. */
@@ -579,3 +695,138 @@ xfs_rtrmapbt_calc_reserves(
return max_t(xfs_filblks_t, blocks / 100,
xfs_rtrmapbt_max_size(mp, blocks));
}
+
+/* Convert on-disk form of btree root to in-memory form. */
+STATIC void
+xfs_rtrmapbt_from_disk(
+ struct xfs_inode *ip,
+ struct xfs_rtrmap_root *dblock,
+ unsigned int dblocklen,
+ struct xfs_btree_block *rblock)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_rmap_key *fkp;
+ __be64 *fpp;
+ struct xfs_rmap_key *tkp;
+ __be64 *tpp;
+ struct xfs_rmap_rec *frp;
+ struct xfs_rmap_rec *trp;
+ unsigned int rblocklen = xfs_rtrmap_broot_space(mp, dblock);
+ unsigned int numrecs;
+ unsigned int maxrecs;
+
+ xfs_btree_init_block(mp, rblock, &xfs_rtrmapbt_ops, 0, 0, ip->i_ino);
+
+ rblock->bb_level = dblock->bb_level;
+ rblock->bb_numrecs = dblock->bb_numrecs;
+ numrecs = be16_to_cpu(dblock->bb_numrecs);
+
+ if (be16_to_cpu(rblock->bb_level) > 0) {
+ maxrecs = xfs_rtrmapbt_droot_maxrecs(dblocklen, false);
+ fkp = xfs_rtrmap_droot_key_addr(dblock, 1);
+ tkp = xfs_rtrmap_key_addr(rblock, 1);
+ fpp = xfs_rtrmap_droot_ptr_addr(dblock, 1, maxrecs);
+ tpp = xfs_rtrmap_broot_ptr_addr(mp, rblock, 1, rblocklen);
+ memcpy(tkp, fkp, 2 * sizeof(*fkp) * numrecs);
+ memcpy(tpp, fpp, sizeof(*fpp) * numrecs);
+ } else {
+ frp = xfs_rtrmap_droot_rec_addr(dblock, 1);
+ trp = xfs_rtrmap_rec_addr(rblock, 1);
+ memcpy(trp, frp, sizeof(*frp) * numrecs);
+ }
+}
+
+/* Load a realtime reverse mapping btree root in from disk. */
+int
+xfs_iformat_rtrmap(
+ struct xfs_inode *ip,
+ struct xfs_dinode *dip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_rtrmap_root *dfp = XFS_DFORK_PTR(dip, XFS_DATA_FORK);
+ struct xfs_btree_block *broot;
+ unsigned int numrecs;
+ unsigned int level;
+ int dsize;
+
+ /*
+ * growfs must create the rtrmap inodes before adding a realtime volume
+ * to the filesystem, so we cannot use the rtrmapbt predicate here.
+ */
+ if (!xfs_has_rmapbt(ip->i_mount))
+ return -EFSCORRUPTED;
+
+ dsize = XFS_DFORK_SIZE(dip, mp, XFS_DATA_FORK);
+ numrecs = be16_to_cpu(dfp->bb_numrecs);
+ level = be16_to_cpu(dfp->bb_level);
+
+ if (level > mp->m_rtrmap_maxlevels ||
+ xfs_rtrmap_droot_space_calc(level, numrecs) > dsize)
+ return -EFSCORRUPTED;
+
+ broot = xfs_broot_alloc(xfs_ifork_ptr(ip, XFS_DATA_FORK),
+ xfs_rtrmap_broot_space_calc(mp, level, numrecs));
+ if (broot)
+ xfs_rtrmapbt_from_disk(ip, dfp, dsize, broot);
+ return 0;
+}
+
+/* Convert in-memory form of btree root to on-disk form. */
+void
+xfs_rtrmapbt_to_disk(
+ struct xfs_mount *mp,
+ struct xfs_btree_block *rblock,
+ unsigned int rblocklen,
+ struct xfs_rtrmap_root *dblock,
+ unsigned int dblocklen)
+{
+ struct xfs_rmap_key *fkp;
+ __be64 *fpp;
+ struct xfs_rmap_key *tkp;
+ __be64 *tpp;
+ struct xfs_rmap_rec *frp;
+ struct xfs_rmap_rec *trp;
+ unsigned int numrecs;
+ unsigned int maxrecs;
+
+ ASSERT(rblock->bb_magic == cpu_to_be32(XFS_RTRMAP_CRC_MAGIC));
+ ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid));
+ ASSERT(rblock->bb_u.l.bb_blkno == cpu_to_be64(XFS_BUF_DADDR_NULL));
+ ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
+ ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
+
+ dblock->bb_level = rblock->bb_level;
+ dblock->bb_numrecs = rblock->bb_numrecs;
+ numrecs = be16_to_cpu(rblock->bb_numrecs);
+
+ if (be16_to_cpu(rblock->bb_level) > 0) {
+ maxrecs = xfs_rtrmapbt_droot_maxrecs(dblocklen, false);
+ fkp = xfs_rtrmap_key_addr(rblock, 1);
+ tkp = xfs_rtrmap_droot_key_addr(dblock, 1);
+ fpp = xfs_rtrmap_broot_ptr_addr(mp, rblock, 1, rblocklen);
+ tpp = xfs_rtrmap_droot_ptr_addr(dblock, 1, maxrecs);
+ memcpy(tkp, fkp, 2 * sizeof(*fkp) * numrecs);
+ memcpy(tpp, fpp, sizeof(*fpp) * numrecs);
+ } else {
+ frp = xfs_rtrmap_rec_addr(rblock, 1);
+ trp = xfs_rtrmap_droot_rec_addr(dblock, 1);
+ memcpy(trp, frp, sizeof(*frp) * numrecs);
+ }
+}
+
+/* Flush a realtime reverse mapping btree root out to disk. */
+void
+xfs_iflush_rtrmap(
+ struct xfs_inode *ip,
+ struct xfs_dinode *dip)
+{
+ struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
+ struct xfs_rtrmap_root *dfp = XFS_DFORK_PTR(dip, XFS_DATA_FORK);
+
+ ASSERT(ifp->if_broot != NULL);
+ ASSERT(ifp->if_broot_bytes > 0);
+ ASSERT(xfs_rtrmap_droot_space(ifp->if_broot) <=
+ xfs_inode_fork_size(ip, XFS_DATA_FORK));
+ xfs_rtrmapbt_to_disk(ip->i_mount, ifp->if_broot, ifp->if_broot_bytes,
+ dfp, XFS_DFORK_SIZE(dip, ip->i_mount, XFS_DATA_FORK));
+}
diff --git a/libxfs/xfs_rtrmap_btree.h b/libxfs/xfs_rtrmap_btree.h
index eaa2942297e20c..e97695066920ee 100644
--- a/libxfs/xfs_rtrmap_btree.h
+++ b/libxfs/xfs_rtrmap_btree.h
@@ -25,6 +25,7 @@ void xfs_rtrmapbt_commit_staged_btree(struct xfs_btree_cur *cur,
unsigned int xfs_rtrmapbt_maxrecs(struct xfs_mount *mp, unsigned int blocklen,
bool leaf);
void xfs_rtrmapbt_compute_maxlevels(struct xfs_mount *mp);
+unsigned int xfs_rtrmapbt_droot_maxrecs(unsigned int blocklen, bool leaf);

/*
* Addresses of records, keys, and pointers within an incore rtrmapbt block.
@@ -81,4 +82,115 @@ void xfs_rtrmapbt_destroy_cur_cache(void);

xfs_filblks_t xfs_rtrmapbt_calc_reserves(struct xfs_mount *mp);

+/* Addresses of key, pointers, and records within an ondisk rtrmapbt block. */
+
+static inline struct xfs_rmap_rec *
+xfs_rtrmap_droot_rec_addr(
+ struct xfs_rtrmap_root *block,
+ unsigned int index)
+{
+ return (struct xfs_rmap_rec *)
+ ((char *)(block + 1) +
+ (index - 1) * sizeof(struct xfs_rmap_rec));
+}
+
+static inline struct xfs_rmap_key *
+xfs_rtrmap_droot_key_addr(
+ struct xfs_rtrmap_root *block,
+ unsigned int index)
+{
+ return (struct xfs_rmap_key *)
+ ((char *)(block + 1) +
+ (index - 1) * 2 * sizeof(struct xfs_rmap_key));
+}
+
+static inline xfs_rtrmap_ptr_t *
+xfs_rtrmap_droot_ptr_addr(
+ struct xfs_rtrmap_root *block,
+ unsigned int index,
+ unsigned int maxrecs)
+{
+ return (xfs_rtrmap_ptr_t *)
+ ((char *)(block + 1) +
+ maxrecs * 2 * sizeof(struct xfs_rmap_key) +
+ (index - 1) * sizeof(xfs_rtrmap_ptr_t));
+}
+
+/*
+ * Address of pointers within the incore btree root.
+ *
+ * These are to be used when we know the size of the block and
+ * we don't have a cursor.
+ */
+static inline xfs_rtrmap_ptr_t *
+xfs_rtrmap_broot_ptr_addr(
+ struct xfs_mount *mp,
+ struct xfs_btree_block *bb,
+ unsigned int index,
+ unsigned int block_size)
+{
+ return xfs_rtrmap_ptr_addr(bb, index,
+ xfs_rtrmapbt_maxrecs(mp, block_size, false));
+}
+
+/*
+ * Compute the space required for the incore btree root containing the given
+ * number of records.
+ */
+static inline size_t
+xfs_rtrmap_broot_space_calc(
+ struct xfs_mount *mp,
+ unsigned int level,
+ unsigned int nrecs)
+{
+ size_t sz = XFS_RTRMAP_BLOCK_LEN;
+
+ if (level > 0)
+ return sz + nrecs * (2 * sizeof(struct xfs_rmap_key) +
+ sizeof(xfs_rtrmap_ptr_t));
+ return sz + nrecs * sizeof(struct xfs_rmap_rec);
+}
+
+/*
+ * Compute the space required for the incore btree root given the ondisk
+ * btree root block.
+ */
+static inline size_t
+xfs_rtrmap_broot_space(struct xfs_mount *mp, struct xfs_rtrmap_root *bb)
+{
+ return xfs_rtrmap_broot_space_calc(mp, be16_to_cpu(bb->bb_level),
+ be16_to_cpu(bb->bb_numrecs));
+}
+
+/* Compute the space required for the ondisk root block. */
+static inline size_t
+xfs_rtrmap_droot_space_calc(
+ unsigned int level,
+ unsigned int nrecs)
+{
+ size_t sz = sizeof(struct xfs_rtrmap_root);
+
+ if (level > 0)
+ return sz + nrecs * (2 * sizeof(struct xfs_rmap_key) +
+ sizeof(xfs_rtrmap_ptr_t));
+ return sz + nrecs * sizeof(struct xfs_rmap_rec);
+}
+
+/*
+ * Compute the space required for the ondisk root block given an incore root
+ * block.
+ */
+static inline size_t
+xfs_rtrmap_droot_space(struct xfs_btree_block *bb)
+{
+ return xfs_rtrmap_droot_space_calc(be16_to_cpu(bb->bb_level),
+ be16_to_cpu(bb->bb_numrecs));
+}
+
+int xfs_iformat_rtrmap(struct xfs_inode *ip, struct xfs_dinode *dip);
+void xfs_rtrmapbt_to_disk(struct xfs_mount *mp, struct xfs_btree_block *rblock,
+ unsigned int rblocklen, struct xfs_rtrmap_root *dblock,
+ unsigned int dblocklen);
+void xfs_iflush_rtrmap(struct xfs_inode *ip, struct xfs_dinode *dip);
+
#endif /* __XFS_RTRMAP_BTREE_H__ */