This patch adds a new function named ext4_flex_group_add() which adds a
flex group to a fs. The function is used by 64bit-resize interface.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
---
fs/ext4/resize.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 82 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index d4b892f..14082c0 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1787,3 +1787,85 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
exit_put:
return err;
} /* ext4_group_extend */
+
+/* Add a flex group to an fs. Ensure we handle all possible error conditions
+ * _before_ we start modifying the filesystem, because we cannot abort the
+ * transaction and not have it write the data to disk.
+ */
+static int ext4_flex_group_add(struct super_block *sb,
+ struct inode *resize_inode,
+ struct ext4_new_flex_group_data *flex_gd)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_super_block *es = sbi->s_es;
+ ext4_fsblk_t o_blocks_count;
+ ext4_grpblk_t last;
+ ext4_group_t group;
+ handle_t *handle;
+ unsigned reserved_gdb;
+ int err = 0, err2 = 0, credit;
+
+ BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
+
+ reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
+ o_blocks_count = ext4_blocks_count(es);
+ ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
+ BUG_ON(last);
+
+ err = setup_new_flex_group_blocks(sb, flex_gd);
+ if (err)
+ goto exit;
+ /*
+ * We will always be modifying at least the superblock and GDT
+ * block. If we are adding a group past the last current GDT block,
+ * we will also modify the inode and the dindirect block. If we
+ * are adding a group with superblock/GDT backups we will also
+ * modify each of the reserved GDT dindirect blocks.
+ */
+ credit = flex_gd->count * 4 + reserved_gdb;
+ handle = ext4_journal_start_sb(sb, credit);
+ if (IS_ERR(handle)) {
+ err = PTR_ERR(handle);
+ goto exit;
+ }
+
+ err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+ if (err)
+ goto exit_journal;
+
+ group = flex_gd->groups[0].group;
+ BUG_ON(group != EXT4_SB(sb)->s_groups_count);
+ err = ext4_add_new_descs(handle, sb, group,
+ resize_inode, flex_gd->count);
+ if (err)
+ goto exit_journal;
+
+ err = ext4_setup_new_descs(handle, sb, flex_gd);
+ if (err)
+ goto exit_journal;
+
+ ext4_update_super(sb, flex_gd);
+
+ err = ext4_handle_dirty_super(handle, sb);
+
+exit_journal:
+ err2 = ext4_journal_stop(handle);
+ if (!err)
+ err = err2;
+
+ if (!err) {
+ int i;
+ update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
+ sizeof(struct ext4_super_block));
+ for (i = 0; i < flex_gd->count; i++, group++) {
+ struct buffer_head *gdb_bh;
+ int gdb_num;
+ gdb_num = group / EXT4_BLOCKS_PER_GROUP(sb);
+ gdb_bh = sbi->s_group_desc[gdb_num];
+ update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
+ gdb_bh->b_size);
+ }
+ }
+exit:
+ return err;
+}
--
1.7.5.1
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