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authorYongqiang Yang <xiaoqiangnk@gmail.com>2012-01-03 23:20:50 -0500
committerTheodore Ts'o <tytso@mit.edu>2012-01-03 23:20:50 -0500
commitbb08c1e7d8c072da338f6d905a89376b36023017 (patch)
tree01c403e7e76c5ab19b9852ba774dc138c7249482 /fs/ext4/resize.c
parent18e3143848f1abdd07e7d9879cf67f4e147ff8b7 (diff)
ext4: add a function which adds a new group descriptors to a fs
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@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/resize.c')
-rw-r--r--fs/ext4/resize.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 1c3c2b56049..3bb4e7b502e 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