[PATCH 2/2] xfs: refactor xfs_fs_statfs

[Christoph Hellwig <hch@lst.de>]

Split out helpers for data, rt data and inode related information, and
assigning f_bavail once instead of in three places.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_qm_bhv.c |   1 -
 fs/xfs/xfs_super.c  | 132 ++++++++++++++++++++++++++------------------
 2 files changed, 78 insertions(+), 55 deletions(-)

diff --git a/fs/xfs/xfs_qm_bhv.c b/fs/xfs/xfs_qm_bhv.c
index db5b8afd9d1b..37f1230e7584 100644
--- a/fs/xfs/xfs_qm_bhv.c
+++ b/fs/xfs/xfs_qm_bhv.c
@@ -40,7 +40,6 @@ xfs_fill_statvfs_from_dquot(
 
 		statp->f_blocks = min(statp->f_blocks, limit);
 		statp->f_bfree = min(statp->f_bfree, remaining);
-		statp->f_bavail = min(statp->f_bavail, remaining);
 	}
 
 	limit = dqp->q_ino.softlimit ?
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 20cc00b992a6..809ac6d1813c 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -819,81 +819,105 @@ xfs_fs_sync_fs(
 	return 0;
 }
 
-STATIC int
-xfs_fs_statfs(
-	struct dentry		*dentry,
-	struct kstatfs		*statp)
+static xfs_extlen_t
+xfs_internal_log_size(
+	struct xfs_mount	*mp)
 {
-	struct xfs_mount	*mp = XFS_M(dentry->d_sb);
-	xfs_sb_t		*sbp = &mp->m_sb;
-	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
-	uint64_t		fakeinos, id;
-	uint64_t		icount;
-	uint64_t		ifree;
-	uint64_t		fdblocks;
-	xfs_extlen_t		lsize;
-	int64_t			ffree;
-
-	/*
-	 * Expedite background inodegc but don't wait. We do not want to block
-	 * here waiting hours for a billion extent file to be truncated.
-	 */
-	xfs_inodegc_push(mp);
-
-	statp->f_type = XFS_SUPER_MAGIC;
-	statp->f_namelen = MAXNAMELEN - 1;
-
-	id = huge_encode_dev(mp->m_ddev_targp->bt_dev);
-	statp->f_fsid = u64_to_fsid(id);
+	if (!mp->m_sb.sb_logstart)
+		return 0;
+	return mp->m_sb.sb_logblocks;
+}
 
-	icount = percpu_counter_sum(&mp->m_icount);
-	ifree = percpu_counter_sum(&mp->m_ifree);
-	fdblocks = percpu_counter_sum(&mp->m_fdblocks);
+static void
+xfs_statfs_data(
+	struct xfs_mount	*mp,
+	struct kstatfs		*st)
+{
+	int64_t			fdblocks =
+		percpu_counter_sum(&mp->m_fdblocks);
 
-	statp->f_bsize = sbp->sb_blocksize;
-	lsize = sbp->sb_logstart ? sbp->sb_logblocks : 0;
+	/* make sure st->f_bfree does not underflow */
+	st->f_bfree = max(0LL, fdblocks - xfs_fdblocks_unavailable(mp));
 	/*
 	 * sb_dblocks can change during growfs, but nothing cares about reporting
 	 * the old or new value during growfs.
 	 */
-	statp->f_blocks = sbp->sb_dblocks - lsize;
+	st->f_blocks = mp->m_sb.sb_dblocks - xfs_internal_log_size(mp);
+}
+
+/*
+ * When stat(v)fs is called on a file with the realtime bit set or a directory
+ * with the rtinherit bit, report freespace information for the RT device
+ * instead of the main data device.
+ */
+static void
+xfs_statfs_rt(
+	struct xfs_mount	*mp,
+	struct kstatfs		*st)
+{
+	st->f_bfree = xfs_rtbxlen_to_blen(mp,
+			percpu_counter_sum_positive(&mp->m_frextents));
+	st->f_blocks = mp->m_sb.sb_rblocks;
+}
 
-	/* make sure statp->f_bfree does not underflow */
-	statp->f_bfree = max_t(int64_t, 0,
-				fdblocks - xfs_fdblocks_unavailable(mp));
-	statp->f_bavail = statp->f_bfree;
+static void
+xfs_statfs_inodes(
+	struct xfs_mount	*mp,
+	struct kstatfs		*st)
+{
+	uint64_t		icount = percpu_counter_sum(&mp->m_icount);
+	uint64_t		ifree = percpu_counter_sum(&mp->m_ifree);
+	uint64_t		fakeinos = XFS_FSB_TO_INO(mp, st->f_bfree);
 
-	fakeinos = XFS_FSB_TO_INO(mp, statp->f_bfree);
-	statp->f_files = min(icount + fakeinos, (uint64_t)XFS_MAXINUMBER);
+	st->f_files = min(icount + fakeinos, (uint64_t)XFS_MAXINUMBER);
 	if (M_IGEO(mp)->maxicount)
-		statp->f_files = min_t(typeof(statp->f_files),
-					statp->f_files,
+		st->f_files = min_t(typeof(st->f_files), st->f_files,
 					M_IGEO(mp)->maxicount);
 
 	/* If sb_icount overshot maxicount, report actual allocation */
-	statp->f_files = max_t(typeof(statp->f_files),
-					statp->f_files,
-					sbp->sb_icount);
+	st->f_files = max_t(typeof(st->f_files), st->f_files,
+			mp->m_sb.sb_icount);
 
-	/* make sure statp->f_ffree does not underflow */
-	ffree = statp->f_files - (icount - ifree);
-	statp->f_ffree = max_t(int64_t, ffree, 0);
+	/* Make sure st->f_ffree does not underflow */
+	st->f_ffree = max_t(int64_t, 0, st->f_files - (icount - ifree));
+}
 
-	if (XFS_IS_REALTIME_MOUNT(mp) &&
-	    (ip->i_diflags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME))) {
-		s64	freertx;
+STATIC int
+xfs_fs_statfs(
+	struct dentry		*dentry,
+	struct kstatfs		*st)
+{
+	struct xfs_mount	*mp = XFS_M(dentry->d_sb);
+	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
 
-		statp->f_blocks = sbp->sb_rblocks;
-		freertx = percpu_counter_sum_positive(&mp->m_frextents);
-		statp->f_bavail = statp->f_bfree =
-			xfs_rtbxlen_to_blen(mp, freertx);
-	}
+	/*
+	 * Expedite background inodegc but don't wait. We do not want to block
+	 * here waiting hours for a billion extent file to be truncated.
+	 */
+	xfs_inodegc_push(mp);
+
+	st->f_type = XFS_SUPER_MAGIC;
+	st->f_namelen = MAXNAMELEN - 1;
+	st->f_bsize = mp->m_sb.sb_blocksize;
+	st->f_fsid = u64_to_fsid(huge_encode_dev(mp->m_ddev_targp->bt_dev));
+
+	xfs_statfs_data(mp, st);
+	xfs_statfs_inodes(mp, st);
+
+	if (XFS_IS_REALTIME_MOUNT(mp) &&
+	    (ip->i_diflags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME)))
+		xfs_statfs_rt(mp, st);
 
 	if ((ip->i_diflags & XFS_DIFLAG_PROJINHERIT) &&
 	    ((mp->m_qflags & (XFS_PQUOTA_ACCT|XFS_PQUOTA_ENFD))) ==
 			      (XFS_PQUOTA_ACCT|XFS_PQUOTA_ENFD))
-		xfs_qm_statvfs(ip, statp);
+		xfs_qm_statvfs(ip, st);
 
+	/*
+	 * XFS does not distinguish between blocks available to privileged and
+	 * unprivileged users.
+	 */
+	st->f_bavail = st->f_bfree;
 	return 0;
 }
 
-- 
2.45.2