[PATCH V3 09/12] 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. To hold 64-bit extent counters, carve out the new 64-bit field
   xfs_bulkstat->bs_extents64 from xfs_bulkstat->bs_pad[].
2. Carve out a new 64-bit field xfs_bulk_ireq->bulkstat_flags from
   xfs_bulk_ireq->reserved[] to hold bulkstat specific operational flags.  As of
   this commit, XFS_IBULK_NREXT64 is the only valid flag that this field can
   hold. It indicates that userspace has the necessary infrastructure to
   receive 64-bit extent counters.
3. Define the new flag XFS_BULK_IREQ_BULKSTAT for userspace to indicate that
   xfs_bulk_ireq->bulkstat_flags has valid flags set.

Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
---
 fs/xfs/libxfs/xfs_fs.h | 19 ++++++++++++++-----
 fs/xfs/xfs_ioctl.c     |  7 +++++++
 fs/xfs/xfs_itable.c    | 25 +++++++++++++++++++++++--
 fs/xfs/xfs_itable.h    |  2 ++
 fs/xfs/xfs_iwalk.h     |  7 +++++--
 5 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 2594fb647384..b76906914d89 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -394,7 +394,7 @@ 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_extents32;	/* 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	*/
@@ -403,8 +403,9 @@ 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)
@@ -469,7 +470,8 @@ struct xfs_bulk_ireq {
 	uint32_t	icount;		/* I: count of entries in buffer */
 	uint32_t	ocount;		/* O: count of entries filled out */
 	uint32_t	agno;		/* I: see comment for IREQ_AGNO	*/
-	uint64_t	reserved[5];	/* must be zero			*/
+	uint64_t	bulkstat_flags; /* I: Bulkstat operation flags */
+	uint64_t	reserved[4];	/* must be zero			*/
 };
 
 /*
@@ -492,9 +494,16 @@ struct xfs_bulk_ireq {
  */
 #define XFS_BULK_IREQ_METADIR	(1 << 2)
 
-#define XFS_BULK_IREQ_FLAGS_ALL	(XFS_BULK_IREQ_AGNO | \
+#define XFS_BULK_IREQ_BULKSTAT	(1 << 3)
+
+#define XFS_BULK_IREQ_FLAGS_ALL	(XFS_BULK_IREQ_AGNO |	 \
 				 XFS_BULK_IREQ_SPECIAL | \
-				 XFS_BULK_IREQ_METADIR)
+				 XFS_BULK_IREQ_METADIR | \
+				 XFS_BULK_IREQ_BULKSTAT)
+
+#define XFS_BULK_IREQ_BULKSTAT_NREXT64 (1 << 0)
+
+#define XFS_BULK_IREQ_BULKSTAT_FLAGS_ALL (XFS_BULK_IREQ_BULKSTAT_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 4077862fa806..207c96bbc729 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -839,6 +839,10 @@ xfs_bulk_ireq_setup(
 {
 	if (hdr->icount == 0 ||
 	    (hdr->flags & ~XFS_BULK_IREQ_FLAGS_ALL) ||
+	    ((hdr->flags & XFS_BULK_IREQ_BULKSTAT) &&
+	     (hdr->bulkstat_flags & ~XFS_BULK_IREQ_BULKSTAT_FLAGS_ALL)) ||
+	    (!(hdr->flags & XFS_BULK_IREQ_BULKSTAT) &&
+	     (hdr->bulkstat_flags != 0)) ||
 	    memchr_inv(hdr->reserved, 0, sizeof(hdr->reserved)))
 		return -EINVAL;
 
@@ -897,6 +901,9 @@ xfs_bulk_ireq_setup(
 	if (hdr->flags & XFS_BULK_IREQ_METADIR)
 		breq->flags |= XFS_IWALK_METADIR;
 
+	if (hdr->flags & XFS_BULK_IREQ_BULKSTAT)
+		if (hdr->bulkstat_flags & XFS_BULK_IREQ_BULKSTAT_NREXT64)
+			breq->flags |= XFS_IBULK_NREXT64;
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index f92057ad686b..5dce090f8f65 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
@@ -74,6 +75,7 @@ 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;
 
 	error = xfs_iget(mp, tp, ino,
@@ -134,7 +136,26 @@ 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_IFORK_EXTCNT_MAXS32;
+
+		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 = -EINVAL;
+			goto out_advance;
+		}
+		buf->bs_extents32 = 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);
@@ -356,7 +377,7 @@ xfs_bulkstat_to_bstat(
 	bs1->bs_blocks = bstat->bs_blocks;
 	bs1->bs_xflags = bstat->bs_xflags;
 	bs1->bs_extsize = XFS_FSB_TO_B(mp, bstat->bs_extsize_blks);
-	bs1->bs_extents = bstat->bs_extents;
+	bs1->bs_extents = bstat->bs_extents32;
 	bs1->bs_gen = bstat->bs_gen;
 	bs1->bs_projid_lo = bstat->bs_projectid & 0xFFFF;
 	bs1->bs_forkoff = bstat->bs_forkoff;
diff --git a/fs/xfs/xfs_itable.h b/fs/xfs/xfs_itable.h
index f5a13f69883a..f61685da3837 100644
--- a/fs/xfs/xfs_itable.h
+++ b/fs/xfs/xfs_itable.h
@@ -22,6 +22,8 @@ struct xfs_ibulk {
 /* Signal that we can return metadata directories. */
 #define XFS_IBULK_METADIR	(XFS_IWALK_METADIR)
 
+#define XFS_IBULK_NREXT64	(XFS_IWALK_NREXT64)
+
 /*
  * 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 d7a082e45cbf..27a6842a1bb5 100644
--- a/fs/xfs/xfs_iwalk.h
+++ b/fs/xfs/xfs_iwalk.h
@@ -31,8 +31,11 @@ int xfs_iwalk_threaded(struct xfs_mount *mp, xfs_ino_t startino,
 /* Signal that we can return metadata directories. */
 #define XFS_IWALK_METADIR	(0x2)
 
-#define XFS_IWALK_FLAGS_ALL	(XFS_IWALK_SAME_AG | \
-				 XFS_IWALK_METADIR)
+#define XFS_IWALK_NREXT64	(0x4)
+
+#define XFS_IWALK_FLAGS_ALL	(XFS_IWALK_SAME_AG |	\
+				 XFS_IWALK_METADIR |	\
+				 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