1 files changed, 13 insertions, 4 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9d70c0c177c7..1f7784de05b6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3316,11 +3316,19 @@ int ext4_calculate_overhead(struct super_block *sb)
 }
 
 
-static ext4_fsblk_t ext4_calculate_resv_clusters(struct ext4_sb_info *sbi)
+static ext4_fsblk_t ext4_calculate_resv_clusters(struct super_block *sb)
 {
         ext4_fsblk_t resv_clusters;
 
         /*
+         * There's no need to reserve anything when we aren't using extents.
+         * The space estimates are exact, there are no unwritten extents,
+         * hole punching doesn't need new metadata... This is needed especially
+         * to keep ext2/3 backward compatibility.
+         */
+        if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
+                return 0;
+        /*
          * By default we reserve 2% or 4096 clusters, whichever is smaller.
          * This should cover the situations where we can not afford to run
          * out of space like for example punch hole, or converting
@@ -3328,7 +3336,8 @@ static ext4_fsblk_t ext4_calculate_resv_clusters(struct ext4_sb_info *sbi)
          * allocation would require 1, or 2 blocks, higher numbers are
          * very rare.
          */
-        resv_clusters = ext4_blocks_count(sbi->s_es) >> sbi->s_cluster_bits;
+        resv_clusters = ext4_blocks_count(EXT4_SB(sb)->s_es) >>
+                        EXT4_SB(sb)->s_cluster_bits;
 
         do_div(resv_clusters, 50);
         resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
@@ -4071,10 +4080,10 @@ no_journal:
                          "available");
         }
 
-        err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sbi));
+        err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sb));
         if (err) {
                 ext4_msg(sb, KERN_ERR, "failed to reserve %llu clusters for "
-                         "reserved pool", ext4_calculate_resv_clusters(sbi));
+                         "reserved pool", ext4_calculate_resv_clusters(sb));
                 goto failed_mount4a;
         }