Cross-reference the reverse mapping data with the refcount btree to find
out which extents are shared.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_fsmap.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 985415b..d729581 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -37,6 +37,8 @@
#include "xfs_alloc.h"
#include "xfs_bit.h"
#include "xfs_fsmap.h"
+#include "xfs_refcount.h"
+#include "xfs_refcount_btree.h"
/* Convert an xfs_fsmap to an fsmap. */
void
@@ -192,6 +194,42 @@ xfs_getfsmap_rec_before_low_key(
return false;
}
+/* Decide if this mapping is shared. */
+STATIC int
+xfs_getfsmap_is_shared(
+ struct xfs_mount *mp,
+ struct xfs_getfsmap_info *info,
+ struct xfs_rmap_irec *rec,
+ bool *stat)
+{
+ struct xfs_btree_cur *cur;
+ xfs_agblock_t fbno;
+ xfs_extlen_t flen;
+ int error;
+
+ *stat = false;
+ if (!xfs_sb_version_hasreflink(&mp->m_sb))
+ return 0;
+ /* rt files will have agno set to NULLAGNUMBER */
+ if (info->agno == NULLAGNUMBER)
+ return 0;
+
+ /* Are there any shared blocks here? */
+ flen = 0;
+ cur = xfs_refcountbt_init_cursor(mp, NULL, info->agf_bp,
+ info->agno, NULL);
+
+ error = xfs_refcount_find_shared(cur, rec->rm_startblock,
+ rec->rm_blockcount, &fbno, &flen, false);
+
+ xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
+ if (error)
+ return error;
+
+ *stat = flen > 0;
+ return 0;
+}
+
/*
* Format a reverse mapping for getfsmap, having translated rm_startblock
* into the appropriate daddr units.
@@ -205,6 +243,7 @@ xfs_getfsmap_helper(
{
struct xfs_fsmap fmr;
xfs_daddr_t key_end;
+ bool shared;
int error;
/*
@@ -304,6 +343,13 @@ xfs_getfsmap_helper(
fmr.fmr_flags |= FMR_OF_ATTR_FORK;
if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
fmr.fmr_flags |= FMR_OF_EXTENT_MAP;
+ if (fmr.fmr_flags == 0) {
+ error = xfs_getfsmap_is_shared(mp, info, rec, &shared);
+ if (error)
+ return error;
+ if (shared)
+ fmr.fmr_flags |= FMR_OF_SHARED;
+ }
error = info->formatter(&fmr, info->format_arg);
if (error)
return error;
--
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