ext4: Do not reserve clusters when fs doesn't support extents

[~andy/linux] / fs / ext4 / super.c

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9d70c0c177c7cb8aec29de2094536b8358ae8679..1f7784de05b6c6afad4d7437202ceb6efeec3399 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3316,10 +3316,18 @@ 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
@@ -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;
        }