ext4: call ext4_mb_mark_context in ext4_mb_mark_diskspace_used

Call ext4_mb_mark_context in ext4_mb_mark_diskspace_used to:
1. Remove repeat code to normally update bitmap and group descriptor
on disk.
2. Now that we have a common API for marking blocks inuse/free in block
bitmap, use that instead of open coding it in function
ext4_mb_mark_diskspace_used(). The current code was not updating
checksum and other counters. ext4_mb_mark_context() should fix these
consistency problems.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230928160407.142069-6-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Author: Kemeng Shi

fs/ext4/mballoc.c

@@ -4053,46 +4053,27 @@ static noinline_for_stack int
 ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 				handle_t *handle, unsigned int reserv_clstrs)
 {
-	struct buffer_head *bitmap_bh = NULL;
 	struct ext4_group_desc *gdp;
-	struct buffer_head *gdp_bh;
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
 	ext4_fsblk_t block;
 	int err, len;
+	int flags = 0;
+	ext4_grpblk_t changed;
 
 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
 	BUG_ON(ac->ac_b_ex.fe_len <= 0);
 
 	sb = ac->ac_sb;
 	sbi = EXT4_SB(sb);
 
-	bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
-	if (IS_ERR(bitmap_bh)) {
-		return PTR_ERR(bitmap_bh);
-	}
-
-	BUFFER_TRACE(bitmap_bh, "getting write access");
-	err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
-					    EXT4_JTR_NONE);
-	if (err)
-		goto out_err;
-
-	err = -EIO;
-	gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
+	gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, NULL);
 	if (!gdp)
-		goto out_err;
-
+		return -EIO;
 	ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
 			ext4_free_group_clusters(sb, gdp));
 
-	BUFFER_TRACE(gdp_bh, "get_write_access");
-	err = ext4_journal_get_write_access(handle, sb, gdp_bh, EXT4_JTR_NONE);
-	if (err)
-		goto out_err;
-
 	block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
-
 	len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
 	if (!ext4_inode_block_valid(ac->ac_inode, block, len)) {
 		ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
@@ -4101,41 +4082,29 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 		 * Fix the bitmap and return EFSCORRUPTED
 		 * We leak some of the blocks here.
 		 */
-		ext4_lock_group(sb, ac->ac_b_ex.fe_group);
-		mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
-			      ac->ac_b_ex.fe_len);
-		ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
-		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+		err = ext4_mb_mark_context(handle, sb, true,
+					   ac->ac_b_ex.fe_group,
+					   ac->ac_b_ex.fe_start,
+					   ac->ac_b_ex.fe_len,
+					   0, NULL);
 		if (!err)
 			err = -EFSCORRUPTED;
-		goto out_err;
+		return err;
 	}
 
-	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
 #ifdef AGGRESSIVE_CHECK
-	{
-		int i;
-		for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
-			BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
-						bitmap_bh->b_data));
-		}
-	}
+	flags |= EXT4_MB_BITMAP_MARKED_CHECK;
 #endif
-	mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
-		      ac->ac_b_ex.fe_len);
-	if (ext4_has_group_desc_csum(sb) &&
-	    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
-		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
-		ext4_free_group_clusters_set(sb, gdp,
-					     ext4_free_clusters_after_init(sb,
-						ac->ac_b_ex.fe_group, gdp));
-	}
-	len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
-	ext4_free_group_clusters_set(sb, gdp, len);
-	ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
-	ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
+	err = ext4_mb_mark_context(handle, sb, true, ac->ac_b_ex.fe_group,
+				   ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len,
+				   flags, &changed);
+
+	if (err && changed == 0)
+		return err;
 
-	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
+#ifdef AGGRESSIVE_CHECK
+	BUG_ON(changed != ac->ac_b_ex.fe_len);
+#endif
 	percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
 	/*
 	 * Now reduce the dirty block count also. Should not go negative
@@ -4145,21 +4114,6 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 		percpu_counter_sub(&sbi->s_dirtyclusters_counter,
 				   reserv_clstrs);
 
-	if (sbi->s_log_groups_per_flex) {
-		ext4_group_t flex_group = ext4_flex_group(sbi,
-							  ac->ac_b_ex.fe_group);
-		atomic64_sub(ac->ac_b_ex.fe_len,
-			     &sbi_array_rcu_deref(sbi, s_flex_groups,
-						  flex_group)->free_clusters);
-	}
-
-	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
-	if (err)
-		goto out_err;
-	err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
-
-out_err:
-	brelse(bitmap_bh);
 	return err;
 }