From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: [PATCH V7 02/12] ext4: add a function which adds a new group descriptors to a fs Date: Wed, 4 Jan 2012 00:07:24 -0500 Message-ID: <1325653654-10478-3-git-send-email-tytso@mit.edu> References: <1325653654-10478-1-git-send-email-tytso@mit.edu> Cc: Yongqiang Yang , "Theodore Ts'o" To: Ext4 Developers List Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:50285 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750819Ab2ADFHf (ORCPT ); Wed, 4 Jan 2012 00:07:35 -0500 In-Reply-To: <1325653654-10478-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Yongqiang Yang 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 Signed-off-by: "Theodore Ts'o" --- 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