[PATCH v6 04/11] ext4: call ext4_mb_mark_context in ext4_mb_mark_diskspace_used

[Kemeng Shi]

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. call ext4_mb_mark_context instead of only setting bits in block bitmap
to fix the bitmap. Function ext4_mb_mark_context will also update
checksum of bitmap and other counter along with the bit change to keep
the cosistent with bit change or block bitmap will be marked corrupted as
checksum of bitmap is in inconsistent state.

Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Reviewed-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
---
 fs/ext4/mballoc.c | 86 +++++++++++------------------------------------
 1 file changed, 20 insertions(+), 66 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index b066ee018cdb..e650eac22237 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4084,46 +4084,28 @@ 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_mark_context mc;
 	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;
 
 	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);
+	ext4_mb_prepare_mark_context(&mc, handle, sb, 1);
 
-	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 "
@@ -4132,41 +4114,28 @@ 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(&mc, ac->ac_b_ex.fe_group,
+					   ac->ac_b_ex.fe_start,
+					   ac->ac_b_ex.fe_len,
+					   0);
 		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(&mc, ac->ac_b_ex.fe_group,
+				   ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len,
+				   flags);
+
+	if (err && mc.changed == 0)
+		return err;
 
-	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
+#ifdef AGGRESSIVE_CHECK
+	BUG_ON(mc.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
@@ -4176,21 +4145,6 @@ 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;
 }
 
-- 
2.30.0