From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Add a couple of functions to the rmap btrees that will be used
to cross-reference metadata against the rmapbt.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
v2: expand documentation to clarify the behavior of _record_exists
---
fs/xfs/libxfs/xfs_rmap.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_rmap.h | 5 +++
2 files changed, 72 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
index 50db920..79822cf 100644
--- a/fs/xfs/libxfs/xfs_rmap.c
+++ b/fs/xfs/libxfs/xfs_rmap.c
@@ -2387,3 +2387,70 @@ xfs_rmap_compare(
else
return 0;
}
+
+/* Is there a record covering a given extent? */
+int
+xfs_rmap_has_record(
+ struct xfs_btree_cur *cur,
+ xfs_agblock_t bno,
+ xfs_extlen_t len,
+ bool *exists)
+{
+ union xfs_btree_irec low;
+ union xfs_btree_irec high;
+
+ memset(&low, 0, sizeof(low));
+ low.r.rm_startblock = bno;
+ memset(&high, 0xFF, sizeof(high));
+ high.r.rm_startblock = bno + len - 1;
+
+ return xfs_btree_has_record(cur, &low, &high, exists);
+}
+
+/*
+ * Is there a record for this owner completely covering a given physical
+ * extent? If so, *has_rmap will be set to true. If there is no record
+ * or the record only covers part of the range, we set *has_rmap to false.
+ * This function doesn't perform range lookups or offset checks, so it is
+ * not suitable for checking data fork blocks.
+ */
+int
+xfs_rmap_record_exists(
+ struct xfs_btree_cur *cur,
+ xfs_agblock_t bno,
+ xfs_extlen_t len,
+ struct xfs_owner_info *oinfo,
+ bool *has_rmap)
+{
+ uint64_t owner;
+ uint64_t offset;
+ unsigned int flags;
+ int has_record;
+ struct xfs_rmap_irec irec;
+ int error;
+
+ xfs_owner_info_unpack(oinfo, &owner, &offset, &flags);
+ ASSERT(XFS_RMAP_NON_INODE_OWNER(owner) ||
+ (flags & XFS_RMAP_BMBT_BLOCK));
+
+ error = xfs_rmap_lookup_le(cur, bno, len, owner, offset, flags,
+ &has_record);
+ if (error)
+ return error;
+ if (!has_record) {
+ *has_rmap = false;
+ return 0;
+ }
+
+ error = xfs_rmap_get_rec(cur, &irec, &has_record);
+ if (error)
+ return error;
+ if (!has_record) {
+ *has_rmap = false;
+ return 0;
+ }
+
+ *has_rmap = (irec.rm_owner == owner && irec.rm_startblock <= bno &&
+ irec.rm_startblock + irec.rm_blockcount >= bno + len);
+ return 0;
+}
diff --git a/fs/xfs/libxfs/xfs_rmap.h b/fs/xfs/libxfs/xfs_rmap.h
index 0fcd5b1..380e53b 100644
--- a/fs/xfs/libxfs/xfs_rmap.h
+++ b/fs/xfs/libxfs/xfs_rmap.h
@@ -233,5 +233,10 @@ int xfs_rmap_compare(const struct xfs_rmap_irec *a,
union xfs_btree_rec;
int xfs_rmap_btrec_to_irec(union xfs_btree_rec *rec,
struct xfs_rmap_irec *irec);
+int xfs_rmap_has_record(struct xfs_btree_cur *cur, xfs_agblock_t bno,
+ xfs_extlen_t len, bool *exists);
+int xfs_rmap_record_exists(struct xfs_btree_cur *cur, xfs_agblock_t bno,
+ xfs_extlen_t len, struct xfs_owner_info *oinfo,
+ bool *has_rmap);
#endif /* __XFS_RMAP_H__ */
--
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