xfs: split xfs_mod_freecounter

xfs_mod_freecounter has two entirely separate code paths for adding or
subtracting from the free counters.  Only the subtract case looks at the
rsvd flag and can return an error.

Split xfs_mod_freecounter into separate helpers for subtracting or
adding the freecounter, and remove all the impossible to reach error
handling for the addition case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

1 files changed, 35 insertions, 32 deletions

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index d37ba10f5fa3..b9df7cc9c473 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1136,16 +1136,44 @@ xfs_fs_writable(
 	return true;
 }
 
-/* Adjust m_fdblocks or m_frextents. */
+void
+xfs_add_freecounter(
+	struct xfs_mount	*mp,
+	struct percpu_counter	*counter,
+	uint64_t		delta)
+{
+	bool			has_resv_pool = (counter == &mp->m_fdblocks);
+	uint64_t		res_used;
+
+	/*
+	 * If the reserve pool is depleted, put blocks back into it first.
+	 * Most of the time the pool is full.
+	 */
+	if (!has_resv_pool || mp->m_resblks == mp->m_resblks_avail) {
+		percpu_counter_add(counter, delta);
+		return;
+	}
+
+	spin_lock(&mp->m_sb_lock);
+	res_used = mp->m_resblks - mp->m_resblks_avail;
+	if (res_used > delta) {
+		mp->m_resblks_avail += delta;
+	} else {
+		delta -= res_used;
+		mp->m_resblks_avail = mp->m_resblks;
+		percpu_counter_add(counter, delta);
+	}
+	spin_unlock(&mp->m_sb_lock);
+}
+
 int
-xfs_mod_freecounter(
+xfs_dec_freecounter(
 	struct xfs_mount	*mp,
 	struct percpu_counter	*counter,
-	int64_t			delta,
+	uint64_t		delta,
 	bool			rsvd)
 {
 	int64_t			lcounter;
-	long long		res_used;
 	uint64_t		set_aside = 0;
 	s32			batch;
 	bool			has_resv_pool;
@@ -1155,31 +1183,6 @@ xfs_mod_freecounter(
 	if (rsvd)
 		ASSERT(has_resv_pool);
 
-	if (delta > 0) {
-		/*
-		 * If the reserve pool is depleted, put blocks back into it
-		 * first. Most of the time the pool is full.
-		 */
-		if (likely(!has_resv_pool ||
-			   mp->m_resblks == mp->m_resblks_avail)) {
-			percpu_counter_add(counter, delta);
-			return 0;
-		}
-
-		spin_lock(&mp->m_sb_lock);
-		res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
-
-		if (res_used > delta) {
-			mp->m_resblks_avail += delta;
-		} else {
-			delta -= res_used;
-			mp->m_resblks_avail = mp->m_resblks;
-			percpu_counter_add(counter, delta);
-		}
-		spin_unlock(&mp->m_sb_lock);
-		return 0;
-	}
-
 	/*
 	 * Taking blocks away, need to be more accurate the closer we
 	 * are to zero.
@@ -1207,7 +1210,7 @@ xfs_mod_freecounter(
 	 */
 	if (has_resv_pool)
 		set_aside = xfs_fdblocks_unavailable(mp);
-	percpu_counter_add_batch(counter, delta, batch);
+	percpu_counter_add_batch(counter, -((int64_t)delta), batch);
 	if (__percpu_counter_compare(counter, set_aside,
 				     XFS_FDBLOCKS_BATCH) >= 0) {
 		/* we had space! */
@@ -1219,11 +1222,11 @@ xfs_mod_freecounter(
 	 * that took us to ENOSPC.
 	 */
 	spin_lock(&mp->m_sb_lock);
-	percpu_counter_add(counter, -delta);
+	percpu_counter_add(counter, delta);
 	if (!has_resv_pool || !rsvd)
 		goto fdblocks_enospc;
 
-	lcounter = (long long)mp->m_resblks_avail + delta;
+	lcounter = (long long)mp->m_resblks_avail - delta;
 	if (lcounter >= 0) {
 		mp->m_resblks_avail = lcounter;
 		spin_unlock(&mp->m_sb_lock);