Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0acdb887 authored by Tao Ma's avatar Tao Ma Committed by Theodore Ts'o
Browse files

ext4: don't call update_backups() multiple times for the same bg 



When performing an online resize, we add a bunch of groups at one time
in ext4_flex_group_add, so in most cases a lot of group descriptors
will be in the same group block. But in the end of this function,
update_backups will be called for every group descriptor and the same
block will be copied and journalled again and again.  It is really a
waste.

Fix things so we only update a particular bg descriptor block once and
skip subsequent updates of the same block.

Signed-off-by: default avatarTao Ma <boyu.mt@taobao.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 7f1468d1

fs/ext4/resize.c

+4 −0
Original line number Diff line number Diff line
@@ -1460,6 +1460,7 @@ static int ext4_flex_group_add(struct super_block *sb, 
				   EXT4_DESC_PER_BLOCK(sb));

		int meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb,

				EXT4_FEATURE_INCOMPAT_META_BG);

		sector_t old_gdb = 0;



		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,

			       sizeof(struct ext4_super_block), 0);
@@ -1467,8 +1468,11 @@ static int ext4_flex_group_add(struct super_block *sb, 
			struct buffer_head *gdb_bh;



			gdb_bh = sbi->s_group_desc[gdb_num];

			if (old_gdb == gdb_bh->b_blocknr)

				continue;

			update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,

				       gdb_bh->b_size, meta_bg);

			old_gdb = gdb_bh->b_blocknr;

		}

	}

exit: