[PATCH V5 14/16] xfs: Enable bulkstat ioctl to support 64-bit per-inode extent counters

[Chandan Babu R <chandan.babu@oracle.com>]

The following changes are made to enable userspace to obtain 64-bit extent
counters,
1. Carve out a new 64-bit field xfs_bulkstat->bs_extents64 from
   xfs_bulkstat->bs_pad[] to hold 64-bit extent counter.
2. Define the new flag XFS_BULK_IREQ_BULKSTAT for userspace to indicate that
   it is capable of receiving 64-bit extent counters.

Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
---
 fs/xfs/libxfs/xfs_fs.h | 12 ++++++++----
 fs/xfs/xfs_ioctl.c     |  3 +++
 fs/xfs/xfs_itable.c    | 27 +++++++++++++++++++++++++--
 fs/xfs/xfs_itable.h    |  7 ++++++-
 fs/xfs/xfs_iwalk.h     |  7 +++++--
 5 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 42bc39501d81..4e12530eb518 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -393,7 +393,7 @@ struct xfs_bulkstat {
 	uint32_t	bs_extsize_blks; /* extent size hint, blocks	*/
 
 	uint32_t	bs_nlink;	/* number of links		*/
-	uint32_t	bs_extents;	/* number of extents		*/
+	uint32_t	bs_extents;	/* 32-bit data fork extent counter */
 	uint32_t	bs_aextents;	/* attribute number of extents	*/
 	uint16_t	bs_version;	/* structure version		*/
 	uint16_t	bs_forkoff;	/* inode fork offset in bytes	*/
@@ -402,8 +402,9 @@ struct xfs_bulkstat {
 	uint16_t	bs_checked;	/* checked inode metadata	*/
 	uint16_t	bs_mode;	/* type and mode		*/
 	uint16_t	bs_pad2;	/* zeroed			*/
+	uint64_t	bs_extents64;	/* 64-bit data fork extent counter */
 
-	uint64_t	bs_pad[7];	/* zeroed			*/
+	uint64_t	bs_pad[6];	/* zeroed			*/
 };
 
 #define XFS_BULKSTAT_VERSION_V1	(1)
@@ -484,8 +485,11 @@ struct xfs_bulk_ireq {
  */
 #define XFS_BULK_IREQ_SPECIAL	(1 << 1)
 
-#define XFS_BULK_IREQ_FLAGS_ALL	(XFS_BULK_IREQ_AGNO | \
-				 XFS_BULK_IREQ_SPECIAL)
+#define XFS_BULK_IREQ_NREXT64	(1 << 2)
+
+#define XFS_BULK_IREQ_FLAGS_ALL	(XFS_BULK_IREQ_AGNO |	 \
+				 XFS_BULK_IREQ_SPECIAL | \
+				 XFS_BULK_IREQ_NREXT64)
 
 /* Operate on the root directory inode. */
 #define XFS_BULK_IREQ_SPECIAL_ROOT	(1)
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 29231a8c8a45..5d0781745a28 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -893,6 +893,9 @@ xfs_bulk_ireq_setup(
 	if (XFS_INO_TO_AGNO(mp, breq->startino) >= mp->m_sb.sb_agcount)
 		return -ECANCELED;
 
+	if (hdr->flags & XFS_BULK_IREQ_NREXT64)
+		breq->flags |= XFS_IBULK_NREXT64;
+
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index c08c79d9e311..c9b44e8d0235 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
@@ -64,6 +65,7 @@ xfs_bulkstat_one_int(
 	struct xfs_inode	*ip;		/* incore inode pointer */
 	struct inode		*inode;
 	struct xfs_bulkstat	*buf = bc->buf;
+	xfs_extnum_t		nextents;
 	int			error = -EINVAL;
 
 	if (xfs_internal_inum(mp, ino))
@@ -102,7 +104,27 @@ xfs_bulkstat_one_int(
 
 	buf->bs_xflags = xfs_ip2xflags(ip);
 	buf->bs_extsize_blks = ip->i_extsize;
-	buf->bs_extents = xfs_ifork_nextents(&ip->i_df);
+
+	nextents = xfs_ifork_nextents(&ip->i_df);
+	if (!(bc->breq->flags & XFS_IBULK_NREXT64)) {
+		xfs_extnum_t max_nextents = XFS_MAX_EXTCNT_DATA_FORK_OLD;
+
+		if (unlikely(XFS_TEST_ERROR(false, mp,
+				XFS_ERRTAG_REDUCE_MAX_IEXTENTS)))
+			max_nextents = 10;
+
+		if (nextents > max_nextents) {
+			xfs_iunlock(ip, XFS_ILOCK_SHARED);
+			xfs_irele(ip);
+			error = -EOVERFLOW;
+			goto out;
+		}
+
+		buf->bs_extents = nextents;
+	} else {
+		buf->bs_extents64 = nextents;
+	}
+
 	xfs_bulkstat_health(ip, buf);
 	buf->bs_aextents = xfs_ifork_nextents(ip->i_afp);
 	buf->bs_forkoff = XFS_IFORK_BOFF(ip);
@@ -279,7 +301,8 @@ xfs_bulkstat(
 	if (error)
 		goto out;
 
-	error = xfs_iwalk(breq->mp, tp, breq->startino, breq->flags,
+	error = xfs_iwalk(breq->mp, tp, breq->startino,
+			breq->flags & XFS_IBULK_IWALK_MASK,
 			xfs_bulkstat_iwalk, breq->icount, &bc);
 	xfs_trans_cancel(tp);
 out:
diff --git a/fs/xfs/xfs_itable.h b/fs/xfs/xfs_itable.h
index 7078d10c9b12..38f6900176a8 100644
--- a/fs/xfs/xfs_itable.h
+++ b/fs/xfs/xfs_itable.h
@@ -13,12 +13,17 @@ struct xfs_ibulk {
 	xfs_ino_t		startino; /* start with this inode */
 	unsigned int		icount;   /* number of elements in ubuffer */
 	unsigned int		ocount;   /* number of records returned */
-	unsigned int		flags;    /* see XFS_IBULK_FLAG_* */
+	unsigned long long	flags;    /* see XFS_IBULK_FLAG_* */
 };
 
 /* Only iterate within the same AG as startino */
 #define XFS_IBULK_SAME_AG	(XFS_IWALK_SAME_AG)
 
+#define XFS_IBULK_ONLY_OFFSET	32
+#define XFS_IBULK_IWALK_MASK	((1ULL << XFS_IBULK_ONLY_OFFSET) - 1)
+
+#define XFS_IBULK_NREXT64	(1ULL << XFS_IBULK_ONLY_OFFSET)
+
 /*
  * Advance the user buffer pointer by one record of the given size.  If the
  * buffer is now full, return the appropriate error code.
diff --git a/fs/xfs/xfs_iwalk.h b/fs/xfs/xfs_iwalk.h
index 37a795f03267..11be9dbb45c7 100644
--- a/fs/xfs/xfs_iwalk.h
+++ b/fs/xfs/xfs_iwalk.h
@@ -26,9 +26,12 @@ int xfs_iwalk_threaded(struct xfs_mount *mp, xfs_ino_t startino,
 		unsigned int inode_records, bool poll, void *data);
 
 /* Only iterate inodes within the same AG as @startino. */
-#define XFS_IWALK_SAME_AG	(0x1)
+#define XFS_IWALK_SAME_AG	(1 << 0)
 
-#define XFS_IWALK_FLAGS_ALL	(XFS_IWALK_SAME_AG)
+#define XFS_IWALK_NREXT64	(1 << 1)
+
+#define XFS_IWALK_FLAGS_ALL	(XFS_IWALK_SAME_AG |	\
+				 XFS_IWALK_NREXT64)
 
 /* Walk all inode btree records in the filesystem starting from @startino. */
 typedef int (*xfs_inobt_walk_fn)(struct xfs_mount *mp, struct xfs_trans *tp,
-- 
2.30.2