summary refs log tree commit diff
path: root/fs/ext4
diff options
context:
space:
mode:
authorTao Ma <boyu.mt@taobao.com>2012-09-26 00:08:57 -0400
committerTheodore Ts'o <tytso@mit.edu>2012-09-26 00:08:57 -0400
commit0acdb8876fead922c9ffa6768c5675a37485c48c (patch)
treeb4cca27cf1cff13e704e5eed85a8248a38da8ec7 /fs/ext4
parent7f1468d1d50d368097ab13596dc08eaba7eace7f (diff)
downloadlinux-0acdb8876fead922c9ffa6768c5675a37485c48c.tar.gz
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: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/resize.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index f21fdbf5c75d..7a75e1086961 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1460,6 +1460,7 @@ exit_journal:
 				   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 @@ exit_journal:
 			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: