ext4: add support for online resizing with bigalloc

This patch adds support for online resizing on bigalloc file system by
implementing EXT4_IOC_RESIZE_FS ioctl. Old resize interfaces (add
block groups and extend last block group) are left untouched. Tests
performed with cluster sizes of 1, 2, 4 and 8 blocks (of size 4k) per
cluster. I will add these tests to xfstests.

Signed-off-by: Harshad Shirwadkar <harshads@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

4 files changed, 84 insertions, 58 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 16bf888b187e..53ce95b52fd8 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -545,8 +545,8 @@ struct ext4_new_group_data {
 	__u64 inode_table;
 	__u32 blocks_count;
 	__u16 reserved_blocks;
-	__u16 unused;
-	__u32 free_blocks_count;
+	__u16 mdata_blocks;
+	__u32 free_clusters_count;
 };
 
 /* Indexes used to index group tables in ext4_new_group_data */
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index b0b754b37c36..144bbda2b808 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -871,12 +871,6 @@ group_add_out:
 		int err = 0, err2 = 0;
 		ext4_group_t o_group = EXT4_SB(sb)->s_groups_count;
 
-		if (ext4_has_feature_bigalloc(sb)) {
-			ext4_msg(sb, KERN_ERR,
-				 "Online resizing not (yet) supported with bigalloc");
-			return -EOPNOTSUPP;
-		}
-
 		if (copy_from_user(&n_blocks_count, (__u64 __user *)arg,
 				   sizeof(__u64))) {
 			return -EFAULT;
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 701085620cd8..d9f8b90a93ed 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4994,8 +4994,11 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 	struct ext4_group_desc *desc;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct ext4_buddy e4b;
-	int err = 0, ret, blk_free_count;
-	ext4_grpblk_t blocks_freed;
+	int err = 0, ret, free_clusters_count;
+	ext4_grpblk_t clusters_freed;
+	ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block);
+	ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1);
+	unsigned long cluster_count = last_cluster - first_cluster + 1;
 
 	ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
 
@@ -5007,8 +5010,8 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 	 * Check to see if we are freeing blocks across a group
 	 * boundary.
 	 */
-	if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
-		ext4_warning(sb, "too much blocks added to group %u",
+	if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) {
+		ext4_warning(sb, "too many blocks added to group %u",
 			     block_group);
 		err = -EINVAL;
 		goto error_return;
@@ -5054,14 +5057,14 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 	if (err)
 		goto error_return;
 
-	for (i = 0, blocks_freed = 0; i < count; i++) {
+	for (i = 0, clusters_freed = 0; i < cluster_count; i++) {
 		BUFFER_TRACE(bitmap_bh, "clear bit");
 		if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
 			ext4_error(sb, "bit already cleared for block %llu",
 				   (ext4_fsblk_t)(block + i));
 			BUFFER_TRACE(bitmap_bh, "bit already cleared");
 		} else {
-			blocks_freed++;
+			clusters_freed++;
 		}
 	}
 
@@ -5075,19 +5078,20 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 	 * them with group lock_held
 	 */
 	ext4_lock_group(sb, block_group);
-	mb_clear_bits(bitmap_bh->b_data, bit, count);
-	mb_free_blocks(NULL, &e4b, bit, count);
-	blk_free_count = blocks_freed + ext4_free_group_clusters(sb, desc);
-	ext4_free_group_clusters_set(sb, desc, blk_free_count);
+	mb_clear_bits(bitmap_bh->b_data, bit, cluster_count);
+	mb_free_blocks(NULL, &e4b, bit, cluster_count);
+	free_clusters_count = clusters_freed +
+		ext4_free_group_clusters(sb, desc);
+	ext4_free_group_clusters_set(sb, desc, free_clusters_count);
 	ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh);
 	ext4_group_desc_csum_set(sb, block_group, desc);
 	ext4_unlock_group(sb, block_group);
 	percpu_counter_add(&sbi->s_freeclusters_counter,
-			   EXT4_NUM_B2C(sbi, blocks_freed));
+			   clusters_freed);
 
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
-		atomic64_add(EXT4_NUM_B2C(sbi, blocks_freed),
+		atomic64_add(clusters_freed,
 			     &sbi->s_flex_groups[flex_group].free_clusters);
 	}
 
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 035cd3f4785e..be22d7b425e9 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -106,7 +106,7 @@ static int verify_group_input(struct super_block *sb,
 
 	overhead = ext4_group_overhead_blocks(sb, group);
 	metaend = start + overhead;
-	input->free_blocks_count = free_blocks_count =
+	input->free_clusters_count = free_blocks_count =
 		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 
 	if (test_opt(sb, DEBUG))
@@ -257,6 +257,7 @@ static int ext4_alloc_group_tables(struct super_block *sb,
 	ext4_group_t last_group;
 	unsigned overhead;
 	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
+	int i;
 
 	BUG_ON(flex_gd->count == 0 || group_data == NULL);
 
@@ -293,7 +294,7 @@ next_group:
 		group_data[bb_index].block_bitmap = start_blk++;
 		group = ext4_get_group_number(sb, start_blk - 1);
 		group -= group_data[0].group;
-		group_data[group].free_blocks_count--;
+		group_data[group].mdata_blocks++;
 		flex_gd->bg_flags[group] &= uninit_mask;
 	}
 
@@ -304,7 +305,7 @@ next_group:
 		group_data[ib_index].inode_bitmap = start_blk++;
 		group = ext4_get_group_number(sb, start_blk - 1);
 		group -= group_data[0].group;
-		group_data[group].free_blocks_count--;
+		group_data[group].mdata_blocks++;
 		flex_gd->bg_flags[group] &= uninit_mask;
 	}
 
@@ -323,15 +324,22 @@ next_group:
 		if (start_blk + itb > next_group_start) {
 			flex_gd->bg_flags[group + 1] &= uninit_mask;
 			overhead = start_blk + itb - next_group_start;
-			group_data[group + 1].free_blocks_count -= overhead;
+			group_data[group + 1].mdata_blocks += overhead;
 			itb -= overhead;
 		}
 
-		group_data[group].free_blocks_count -= itb;
+		group_data[group].mdata_blocks += itb;
 		flex_gd->bg_flags[group] &= uninit_mask;
 		start_blk += EXT4_SB(sb)->s_itb_per_group;
 	}
 
+	/* Update free clusters count to exclude metadata blocks */
+	for (i = 0; i < flex_gd->count; i++) {
+		group_data[i].free_clusters_count -=
+				EXT4_NUM_B2C(EXT4_SB(sb),
+					     group_data[i].mdata_blocks);
+	}
+
 	if (test_opt(sb, DEBUG)) {
 		int i;
 		group = group_data[0].group;
@@ -341,12 +349,13 @@ next_group:
 		       flexbg_size);
 
 		for (i = 0; i < flex_gd->count; i++) {
-			printk(KERN_DEBUG "adding %s group %u: %u "
-			       "blocks (%d free)\n",
+			ext4_debug(
+			       "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 			       ext4_bg_has_super(sb, group + i) ? "normal" :
 			       "no-super", group + i,
 			       group_data[i].blocks_count,
-			       group_data[i].free_blocks_count);
+			       group_data[i].free_clusters_count,
+			       group_data[i].mdata_blocks);
 		}
 	}
 	return 0;
@@ -398,7 +407,7 @@ static int extend_or_restart_transaction(handle_t *handle, int thresh)
 }
 
 /*
- * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
+ * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
  *
  * Helper function for ext4_setup_new_group_blocks() which set .
  *
@@ -408,22 +417,26 @@ static int extend_or_restart_transaction(handle_t *handle, int thresh)
  */
 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 			struct ext4_new_flex_group_data *flex_gd,
-			ext4_fsblk_t block, ext4_group_t count)
+			ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 {
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_group_t count = last_cluster - first_cluster + 1;
 	ext4_group_t count2;
 
-	ext4_debug("mark blocks [%llu/%u] used\n", block, count);
-	for (count2 = count; count > 0; count -= count2, block += count2) {
+	ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
+		   last_cluster);
+	for (count2 = count; count > 0;
+	     count -= count2, first_cluster += count2) {
 		ext4_fsblk_t start;
 		struct buffer_head *bh;
 		ext4_group_t group;
 		int err;
 
-		group = ext4_get_group_number(sb, block);
-		start = ext4_group_first_block_no(sb, group);
+		group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
+		start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 		group -= flex_gd->groups[0].group;
 
-		count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
+		count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 		if (count2 > count)
 			count2 = count;
 
@@ -444,9 +457,9 @@ static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 		err = ext4_journal_get_write_access(handle, bh);
 		if (err)
 			return err;
-		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
-			   block - start, count2);
-		ext4_set_bits(bh->b_data, block - start, count2);
+		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
+			   first_cluster, first_cluster - start, count2);
+		ext4_set_bits(bh->b_data, first_cluster - start, count2);
 
 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 		if (unlikely(err))
@@ -595,9 +608,10 @@ handle_bb:
 		if (overhead != 0) {
 			ext4_debug("mark backup superblock %#04llx (+0)\n",
 				   start);
-			ext4_set_bits(bh->b_data, 0, overhead);
+			ext4_set_bits(bh->b_data, 0,
+				      EXT4_NUM_B2C(sbi, overhead));
 		}
-		ext4_mark_bitmap_end(group_data[i].blocks_count,
+		ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 				     sb->s_blocksize * 8, bh->b_data);
 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
 		if (err)
@@ -642,7 +656,11 @@ handle_ib:
 				continue;
 			}
 			err = set_flexbg_block_bitmap(sb, handle,
-						flex_gd, start, count);
+						      flex_gd,
+						      EXT4_B2C(sbi, start),
+						      EXT4_B2C(sbi,
+							       start + count
+							       - 1));
 			if (err)
 				goto out;
 			count = group_table_count[j];
@@ -652,7 +670,11 @@ handle_ib:
 
 		if (count) {
 			err = set_flexbg_block_bitmap(sb, handle,
-						flex_gd, start, count);
+						      flex_gd,
+						      EXT4_B2C(sbi, start),
+						      EXT4_B2C(sbi,
+							       start + count
+							       - 1));
 			if (err)
 				goto out;
 		}
@@ -840,7 +862,8 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
 		ext4_std_error(sb, err);
 		goto exit_inode;
 	}
-	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
+	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
+			   (9 - EXT4_SB(sb)->s_cluster_bits);
 	ext4_mark_iloc_dirty(handle, inode, &iloc);
 	memset(gdb_bh->b_data, 0, sb->s_blocksize);
 	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
@@ -935,6 +958,7 @@ static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 {
 	struct super_block *sb = inode->i_sb;
 	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
+	int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
 	struct buffer_head **primary;
 	struct buffer_head *dind;
 	struct ext4_iloc iloc;
@@ -1010,7 +1034,8 @@ static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 		if (!err)
 			err = err2;
 	}
-	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
+
+	inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
 	ext4_mark_iloc_dirty(handle, inode, &iloc);
 
 exit_bh:
@@ -1244,7 +1269,7 @@ static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
 	ext4_group_t			group;
 	__u16				*bg_flags = flex_gd->bg_flags;
 	int				i, gdb_off, gdb_num, err = 0;
-	
+
 
 	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
 		group = group_data->group;
@@ -1271,7 +1296,7 @@ static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
 
 		ext4_inode_table_set(sb, gdp, group_data->inode_table);
 		ext4_free_group_clusters_set(sb, gdp,
-			EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
+					     group_data->free_clusters_count);
 		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
 		if (ext4_has_group_desc_csum(sb))
 			ext4_itable_unused_set(sb, gdp,
@@ -1327,7 +1352,7 @@ static void ext4_update_super(struct super_block *sb,
 	 */
 	for (i = 0; i < flex_gd->count; i++) {
 		blocks_count += group_data[i].blocks_count;
-		free_blocks += group_data[i].free_blocks_count;
+		free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
 	}
 
 	reserved_blocks = ext4_r_blocks_count(es) * 100;
@@ -1499,17 +1524,18 @@ static int ext4_setup_next_flex_gd(struct super_block *sb,
 				    ext4_fsblk_t n_blocks_count,
 				    unsigned long flexbg_size)
 {
-	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
 	struct ext4_new_group_data *group_data = flex_gd->groups;
 	ext4_fsblk_t o_blocks_count;
 	ext4_group_t n_group;
 	ext4_group_t group;
 	ext4_group_t last_group;
 	ext4_grpblk_t last;
-	ext4_grpblk_t blocks_per_group;
+	ext4_grpblk_t clusters_per_group;
 	unsigned long i;
 
-	blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
+	clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
 
 	o_blocks_count = ext4_blocks_count(es);
 
@@ -1530,9 +1556,10 @@ static int ext4_setup_next_flex_gd(struct super_block *sb,
 		int overhead;
 
 		group_data[i].group = group + i;
-		group_data[i].blocks_count = blocks_per_group;
+		group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
 		overhead = ext4_group_overhead_blocks(sb, group + i);
-		group_data[i].free_blocks_count = blocks_per_group - overhead;
+		group_data[i].mdata_blocks = overhead;
+		group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
 		if (ext4_has_group_desc_csum(sb)) {
 			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
 					       EXT4_BG_INODE_UNINIT;
@@ -1546,10 +1573,10 @@ static int ext4_setup_next_flex_gd(struct super_block *sb,
 		/* We need to initialize block bitmap of last group. */
 		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
 
-	if ((last_group == n_group) && (last != blocks_per_group - 1)) {
-		group_data[i - 1].blocks_count = last + 1;
-		group_data[i - 1].free_blocks_count -= blocks_per_group-
-					last - 1;
+	if ((last_group == n_group) && (last != clusters_per_group - 1)) {
+		group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
+		group_data[i - 1].free_clusters_count -= clusters_per_group -
+						       last - 1;
 	}
 
 	return 1;
@@ -1796,7 +1823,8 @@ static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
 		}
 
 		/* Do a quick sanity check of the resize inode */
-		if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
+		if (inode->i_blocks != 1 << (inode->i_blkbits -
+					     (9 - sbi->s_cluster_bits)))
 			goto invalid_resize_inode;
 		for (i = 0; i < EXT4_N_BLOCKS; i++) {
 			if (i == EXT4_DIND_BLOCK) {
@@ -1959,7 +1987,7 @@ retry:
 	if (n_group == o_group)
 		add = n_blocks_count - o_blocks_count;
 	else
-		add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
+		add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
 	if (add > 0) {
 		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
 		if (err)