From: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
This patch adds a function named ext4_add_new_descs() which adds one
or more new group descriptors to a fs and whose code is copied from
ext4_group_add().
The function will be used by new resize implementation.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
fs/ext4/resize.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 46 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 1c3c2b5..3bb4e7b 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -735,6 +735,52 @@ exit_err:
}
}
+/*
+ * ext4_add_new_descs() adds @count group descriptor of groups
+ * starting at @group
+ *
+ * @handle: journal handle
+ * @sb: super block
+ * @group: the group no. of the first group desc to be added
+ * @resize_inode: the resize inode
+ * @count: number of group descriptors to be added
+ */
+static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
+ ext4_group_t group, struct inode *resize_inode,
+ ext4_group_t count)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_super_block *es = sbi->s_es;
+ struct buffer_head *gdb_bh;
+ int i, gdb_off, gdb_num, err = 0;
+
+ for (i = 0; i < count; i++, group++) {
+ int reserved_gdb = ext4_bg_has_super(sb, group) ?
+ le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
+
+ gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
+ gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+
+ /*
+ * We will only either add reserved group blocks to a backup group
+ * or remove reserved blocks for the first group in a new group block.
+ * Doing both would be mean more complex code, and sane people don't
+ * use non-sparse filesystems anymore. This is already checked above.
+ */
+ if (gdb_off) {
+ gdb_bh = sbi->s_group_desc[gdb_num];
+ err = ext4_journal_get_write_access(handle, gdb_bh);
+
+ if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
+ err = reserve_backup_gdb(handle, resize_inode, group);
+ } else
+ err = add_new_gdb(handle, resize_inode, group);
+ if (err)
+ break;
+ }
+ return err;
+}
+
/* Add group descriptor data to an existing or new group descriptor block.
* Ensure we handle all possible error conditions _before_ we start modifying
* the filesystem, because we cannot abort the transaction and not have it
--
1.7.8.11.gefc1f.dirty
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