[PATCH 098/110] xfs: create a shadow rmap btree during rmap repair

Darrick J. Wong
2024-03-26T03:54:00Z

From: Darrick J. Wong <djwong@kernel.org>

Source kernel commit: 4787fc802752c9b73b28ff18860c0560bf4337f2

Create an in-memory btree of rmap records instead of an array. This
enables us to do live record collection instead of freezing the fs.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
libxfs/xfs_rmap.c | 37 +++++++-----
libxfs/xfs_rmap_btree.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_rmap_btree.h | 6 ++
libxfs/xfs_shared.h | 10 +++
4 files changed, 190 insertions(+), 14 deletions(-)

diff --git a/libxfs/xfs_rmap.c b/libxfs/xfs_rmap.c
index a0b4280fe584..a7be2aa92c0a 100644
--- a/libxfs/xfs_rmap.c
+++ b/libxfs/xfs_rmap.c
@@ -268,6 +268,16 @@ xfs_rmap_check_irec(
return NULL;
}

+static inline xfs_failaddr_t
+xfs_rmap_check_btrec(
+ struct xfs_btree_cur *cur,
+ const struct xfs_rmap_irec *irec)
+{
+ if (xfs_btree_is_mem_rmap(cur->bc_ops))
+ return xfs_rmap_check_irec(cur->bc_mem.pag, irec);
+ return xfs_rmap_check_irec(cur->bc_ag.pag, irec);
+}
+
static inline int
xfs_rmap_complain_bad_rec(
struct xfs_btree_cur *cur,
@@ -276,9 +286,13 @@ xfs_rmap_complain_bad_rec(
{
struct xfs_mount *mp = cur->bc_mp;

- xfs_warn(mp,
- "Reverse Mapping BTree record corruption in AG %d detected at %pS!",
- cur->bc_ag.pag->pag_agno, fa);
+ if (xfs_btree_is_mem_rmap(cur->bc_ops))
+ xfs_warn(mp,
+ "In-Memory Reverse Mapping BTree record corruption detected at %pS!", fa);
+ else
+ xfs_warn(mp,
+ "Reverse Mapping BTree record corruption in AG %d detected at %pS!",
+ cur->bc_ag.pag->pag_agno, fa);
xfs_warn(mp,
"Owner 0x%llx, flags 0x%x, start block 0x%x block count 0x%x",
irec->rm_owner, irec->rm_flags, irec->rm_startblock,
@@ -306,7 +320,7 @@ xfs_rmap_get_rec(

fa = xfs_rmap_btrec_to_irec(rec, irec);
if (!fa)
- fa = xfs_rmap_check_irec(cur->bc_ag.pag, irec);
+ fa = xfs_rmap_check_btrec(cur, irec);
if (fa)
return xfs_rmap_complain_bad_rec(cur, fa, irec);

@@ -2403,15 +2417,12 @@ xfs_rmap_map_raw(
{
struct xfs_owner_info oinfo;

- oinfo.oi_owner = rmap->rm_owner;
- oinfo.oi_offset = rmap->rm_offset;
- oinfo.oi_flags = 0;
- if (rmap->rm_flags & XFS_RMAP_ATTR_FORK)
- oinfo.oi_flags |= XFS_OWNER_INFO_ATTR_FORK;
- if (rmap->rm_flags & XFS_RMAP_BMBT_BLOCK)
- oinfo.oi_flags |= XFS_OWNER_INFO_BMBT_BLOCK;
+ xfs_owner_info_pack(&oinfo, rmap->rm_owner, rmap->rm_offset,
+ rmap->rm_flags);

- if (rmap->rm_flags || XFS_RMAP_NON_INODE_OWNER(rmap->rm_owner))
+ if ((rmap->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK |
+ XFS_RMAP_UNWRITTEN)) ||
+ XFS_RMAP_NON_INODE_OWNER(rmap->rm_owner))
return xfs_rmap_map(cur, rmap->rm_startblock,
rmap->rm_blockcount,
rmap->rm_flags & XFS_RMAP_UNWRITTEN,
@@ -2441,7 +2452,7 @@ xfs_rmap_query_range_helper(

fa = xfs_rmap_btrec_to_irec(rec, &irec);
if (!fa)
- fa = xfs_rmap_check_irec(cur->bc_ag.pag, &irec);
+ fa = xfs_rmap_check_btrec(cur, &irec);
if (fa)
return xfs_rmap_complain_bad_rec(cur, fa, &irec);

diff --git a/libxfs/xfs_rmap_btree.c b/libxfs/xfs_rmap_btree.c
index 956cdc2fd596..a2730e29c8a1 100644
--- a/libxfs/xfs_rmap_btree.c
+++ b/libxfs/xfs_rmap_btree.c
@@ -20,6 +20,9 @@
#include "xfs_ag.h"
#include "xfs_ag_resv.h"
#include "xfs_health.h"
+#include "xfile.h"
+#include "buf_mem.h"
+#include "xfs_btree_mem.h"

static struct kmem_cache *xfs_rmapbt_cur_cache;

@@ -539,6 +542,151 @@ xfs_rmapbt_init_cursor(
return cur;
}

+#ifdef CONFIG_XFS_BTREE_IN_MEM
+static inline unsigned int
+xfs_rmapbt_mem_block_maxrecs(
+ unsigned int blocklen,
+ bool leaf)
+{
+ if (leaf)
+ return blocklen / sizeof(struct xfs_rmap_rec);
+ return blocklen /
+ (2 * sizeof(struct xfs_rmap_key) + sizeof(__be64));
+}
+
+/*
+ * Validate an in-memory rmap btree block. Callers are allowed to generate an
+ * in-memory btree even if the ondisk feature is not enabled.
+ */
+static xfs_failaddr_t
+xfs_rmapbt_mem_verify(
+ struct xfs_buf *bp)
+{
+ struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
+ xfs_failaddr_t fa;
+ unsigned int level;
+ unsigned int maxrecs;
+
+ if (!xfs_verify_magic(bp, block->bb_magic))
+ return __this_address;
+
+ fa = xfs_btree_fsblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
+ if (fa)
+ return fa;
+
+ level = be16_to_cpu(block->bb_level);
+ if (level >= xfs_rmapbt_maxlevels_ondisk())
+ return __this_address;
+
+ maxrecs = xfs_rmapbt_mem_block_maxrecs(
+ XFBNO_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN, level == 0);
+ return xfs_btree_memblock_verify(bp, maxrecs);
+}
+
+static void
+xfs_rmapbt_mem_rw_verify(
+ struct xfs_buf *bp)
+{
+ xfs_failaddr_t fa = xfs_rmapbt_mem_verify(bp);
+
+ if (fa)
+ xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+}
+
+/* skip crc checks on in-memory btrees to save time */
+static const struct xfs_buf_ops xfs_rmapbt_mem_buf_ops = {
+ .name = "xfs_rmapbt_mem",
+ .magic = { 0, cpu_to_be32(XFS_RMAP_CRC_MAGIC) },
+ .verify_read = xfs_rmapbt_mem_rw_verify,
+ .verify_write = xfs_rmapbt_mem_rw_verify,
+ .verify_struct = xfs_rmapbt_mem_verify,
+};
+
+const struct xfs_btree_ops xfs_rmapbt_mem_ops = {
+ .name = "mem_rmap",
+ .type = XFS_BTREE_TYPE_MEM,
+ .geom_flags = XFS_BTGEO_OVERLAPPING,
+
+ .rec_len = sizeof(struct xfs_rmap_rec),
+ /* Overlapping btree; 2 keys per pointer. */
+ .key_len = 2 * sizeof(struct xfs_rmap_key),
+ .ptr_len = XFS_BTREE_LONG_PTR_LEN,
+
+ .lru_refs = XFS_RMAP_BTREE_REF,
+ .statoff = XFS_STATS_CALC_INDEX(xs_rmap_mem_2),
+
+ .dup_cursor = xfbtree_dup_cursor,
+ .set_root = xfbtree_set_root,
+ .alloc_block = xfbtree_alloc_block,
+ .free_block = xfbtree_free_block,
+ .get_minrecs = xfbtree_get_minrecs,
+ .get_maxrecs = xfbtree_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 = xfbtree_init_ptr_from_cur,
+ .key_diff = xfs_rmapbt_key_diff,
+ .buf_ops = &xfs_rmapbt_mem_buf_ops,
+ .diff_two_keys = xfs_rmapbt_diff_two_keys,
+ .keys_inorder = xfs_rmapbt_keys_inorder,
+ .recs_inorder = xfs_rmapbt_recs_inorder,
+ .keys_contiguous = xfs_rmapbt_keys_contiguous,
+};
+
+/* Create a cursor for an in-memory btree. */
+struct xfs_btree_cur *
+xfs_rmapbt_mem_cursor(
+ struct xfs_perag *pag,
+ struct xfs_trans *tp,
+ struct xfbtree *xfbt)
+{
+ struct xfs_btree_cur *cur;
+ struct xfs_mount *mp = pag->pag_mount;
+
+ cur = xfs_btree_alloc_cursor(mp, tp, &xfs_rmapbt_mem_ops,
+ xfs_rmapbt_maxlevels_ondisk(), xfs_rmapbt_cur_cache);
+ cur->bc_mem.xfbtree = xfbt;
+ cur->bc_nlevels = xfbt->nlevels;
+
+ cur->bc_mem.pag = xfs_perag_hold(pag);
+ return cur;
+}
+
+/* Create an in-memory rmap btree. */
+int
+xfs_rmapbt_mem_init(
+ struct xfs_mount *mp,
+ struct xfbtree *xfbt,
+ struct xfs_buftarg *btp,
+ xfs_agnumber_t agno)
+{
+ xfbt->owner = agno;
+ return xfbtree_init(mp, xfbt, btp, &xfs_rmapbt_mem_ops);
+}
+
+/* Compute the max possible height for reverse mapping btrees in memory. */
+static unsigned int
+xfs_rmapbt_mem_maxlevels(void)
+{
+ unsigned int minrecs[2];
+ unsigned int blocklen;
+
+ blocklen = XFBNO_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN;
+
+ minrecs[0] = xfs_rmapbt_mem_block_maxrecs(blocklen, true) / 2;
+ minrecs[1] = xfs_rmapbt_mem_block_maxrecs(blocklen, false) / 2;
+
+ /*
+ * How tall can an in-memory rmap btree become if we filled the entire
+ * AG with rmap records?
+ */
+ return xfs_btree_compute_maxlevels(minrecs,
+ XFS_MAX_AG_BYTES / sizeof(struct xfs_rmap_rec));
+}
+#else
+# define xfs_rmapbt_mem_maxlevels() (0)
+#endif /* CONFIG_XFS_BTREE_IN_MEM */
+
/*
* Install a new reverse mapping btree root. Caller is responsible for
* invalidating and freeing the old btree blocks.
@@ -609,7 +757,8 @@ xfs_rmapbt_maxlevels_ondisk(void)
* like if it consumes almost all the blocks in the AG due to maximal
* sharing factor.
*/
- return xfs_btree_space_to_height(minrecs, XFS_MAX_CRC_AG_BLOCKS);
+ return max(xfs_btree_space_to_height(minrecs, XFS_MAX_CRC_AG_BLOCKS),
+ xfs_rmapbt_mem_maxlevels());
}

/* Compute the maximum height of an rmap btree. */
diff --git a/libxfs/xfs_rmap_btree.h b/libxfs/xfs_rmap_btree.h
index 27536d7e14aa..eb90d89e8086 100644
--- a/libxfs/xfs_rmap_btree.h
+++ b/libxfs/xfs_rmap_btree.h
@@ -10,6 +10,7 @@ struct xfs_buf;
struct xfs_btree_cur;
struct xfs_mount;
struct xbtree_afakeroot;
+struct xfbtree;

/* rmaps only exist on crc enabled filesystems */
#define XFS_RMAP_BLOCK_LEN XFS_BTREE_SBLOCK_CRC_LEN
@@ -62,4 +63,9 @@ unsigned int xfs_rmapbt_maxlevels_ondisk(void);
int __init xfs_rmapbt_init_cur_cache(void);
void xfs_rmapbt_destroy_cur_cache(void);

+struct xfs_btree_cur *xfs_rmapbt_mem_cursor(struct xfs_perag *pag,
+ struct xfs_trans *tp, struct xfbtree *xfbtree);
+int xfs_rmapbt_mem_init(struct xfs_mount *mp, struct xfbtree *xfbtree,
+ struct xfs_buftarg *btp, xfs_agnumber_t agno);
+
#endif /* __XFS_RMAP_BTREE_H__ */
diff --git a/libxfs/xfs_shared.h b/libxfs/xfs_shared.h
index 6b8bc276d461..cab49e7116ec 100644
--- a/libxfs/xfs_shared.h
+++ b/libxfs/xfs_shared.h
@@ -51,6 +51,7 @@ extern const struct xfs_btree_ops xfs_finobt_ops;
extern const struct xfs_btree_ops xfs_bmbt_ops;
extern const struct xfs_btree_ops xfs_refcountbt_ops;
extern const struct xfs_btree_ops xfs_rmapbt_ops;
+extern const struct xfs_btree_ops xfs_rmapbt_mem_ops;

static inline bool xfs_btree_is_bno(const struct xfs_btree_ops *ops)
{
@@ -87,6 +88,15 @@ static inline bool xfs_btree_is_rmap(const struct xfs_btree_ops *ops)
return ops == &xfs_rmapbt_ops;
}

+#ifdef CONFIG_XFS_BTREE_IN_MEM
+static inline bool xfs_btree_is_mem_rmap(const struct xfs_btree_ops *ops)
+{
+ return ops == &xfs_rmapbt_mem_ops;
+}
+#else
+# define xfs_btree_is_mem_rmap(...) (false)
+#endif
+
/* log size calculation functions */
int xfs_log_calc_unit_res(struct xfs_mount *mp, int unit_bytes);
int xfs_log_calc_minimum_size(struct xfs_mount *);