[PATCH V2 12/12] xfs: Error tag to test if v5 bulkstat skips inodes with large extent count

[Chandan Babu R <chandanrlinux@xxxxxxxxx>]

This commit adds a new error tag to allow user space tests to check if V5
bulkstat ioctl skips reporting inodes with large extent count.

Signed-off-by: Chandan Babu R <chandanrlinux@xxxxxxxxx>
---
 fs/xfs/libxfs/xfs_errortag.h | 4 +++-
 fs/xfs/xfs_error.c           | 3 +++
 fs/xfs/xfs_itable.c          | 9 ++++++++-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h
index f5fa2151e05d..b2c533153737 100644
--- a/fs/xfs/libxfs/xfs_errortag.h
+++ b/fs/xfs/libxfs/xfs_errortag.h
@@ -60,7 +60,8 @@
 #define XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT		37
 #define XFS_ERRTAG_AG_RESV_FAIL				38
 #define XFS_ERRTAG_SWAPEXT_FINISH_ONE			39
-#define XFS_ERRTAG_MAX					40
+#define XFS_ERRTAG_BULKSTAT_REDUCE_MAX_IEXTENTS		40
+#define XFS_ERRTAG_MAX					41
 
 /*
  * Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
@@ -105,5 +106,6 @@
 #define XFS_RANDOM_BMAP_ALLOC_MINLEN_EXTENT		1
 #define XFS_RANDOM_AG_RESV_FAIL				1
 #define XFS_RANDOM_SWAPEXT_FINISH_ONE			1
+#define XFS_RANDOM_BULKSTAT_REDUCE_MAX_IEXTENTS		1
 
 #endif /* __XFS_ERRORTAG_H_ */
diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
index e25b440cbfd3..e2a9446fb025 100644
--- a/fs/xfs/xfs_error.c
+++ b/fs/xfs/xfs_error.c
@@ -58,6 +58,7 @@ static unsigned int xfs_errortag_random_default[] = {
 	XFS_RANDOM_BMAP_ALLOC_MINLEN_EXTENT,
 	XFS_RANDOM_AG_RESV_FAIL,
 	XFS_RANDOM_SWAPEXT_FINISH_ONE,
+	XFS_RANDOM_BULKSTAT_REDUCE_MAX_IEXTENTS,
 };
 
 struct xfs_errortag_attr {
@@ -172,6 +173,7 @@ XFS_ERRORTAG_ATTR_RW(reduce_max_iextents,	XFS_ERRTAG_REDUCE_MAX_IEXTENTS);
 XFS_ERRORTAG_ATTR_RW(bmap_alloc_minlen_extent,	XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT);
 XFS_ERRORTAG_ATTR_RW(ag_resv_fail, XFS_ERRTAG_AG_RESV_FAIL);
 XFS_ERRORTAG_ATTR_RW(swapext_finish_one, XFS_RANDOM_SWAPEXT_FINISH_ONE);
+XFS_ERRORTAG_ATTR_RW(bulkstat_reduce_max_iextents, XFS_ERRTAG_BULKSTAT_REDUCE_MAX_IEXTENTS);
 
 static struct attribute *xfs_errortag_attrs[] = {
 	XFS_ERRORTAG_ATTR_LIST(noerror),
@@ -214,6 +216,7 @@ static struct attribute *xfs_errortag_attrs[] = {
 	XFS_ERRORTAG_ATTR_LIST(bmap_alloc_minlen_extent),
 	XFS_ERRORTAG_ATTR_LIST(ag_resv_fail),
 	XFS_ERRORTAG_ATTR_LIST(swapext_finish_one),
+	XFS_ERRORTAG_ATTR_LIST(bulkstat_reduce_max_iextents),
 	NULL,
 };
 
diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index 8493870a0a87..1b252d1cda9d 100644
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -20,6 +20,7 @@
 #include "xfs_icache.h"
 #include "xfs_health.h"
 #include "xfs_trans.h"
+#include "xfs_errortag.h"
 
 /*
  * Bulk Stat
@@ -143,7 +144,13 @@ xfs_bulkstat_one_int(
 
 	nextents = xfs_ifork_nextents(&ip->i_df);
 	if (bc->breq->version != XFS_BULKSTAT_VERSION_V6) {
-		if (nextents > XFS_IFORK_EXTCNT_MAXS32) {
+		xfs_extnum_t max_nextents = XFS_IFORK_EXTCNT_MAXS32;
+
+		if (unlikely(XFS_TEST_ERROR(false, mp,
+				XFS_ERRTAG_BULKSTAT_REDUCE_MAX_IEXTENTS)))
+			max_nextents = 10;
+
+		if (nextents > max_nextents) {
 			xfs_iunlock(ip, XFS_ILOCK_SHARED);
 			xfs_irele(ip);
 			error = -EINVAL;
-- 
2.30.2