[PATCH 2/5] ext4: avoid duplicate writes of the backup bg descriptor blocks
From: Theodore Ts'o <tytso@mit.edu>
Date: 2012-09-02 05:53:20
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
From: Yongqiang Yang <redacted> The resize code was needlessly writing the backup block group descriptor blocks multiple times (once per block group) during an online resize. Signed-off-by: Yongqiang Yang <redacted> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org --- fs/ext4/resize.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 724e250..e3f5f53 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c@@ -1353,13 +1353,15 @@ exit_journal: err = err2; if (!err) { - int i; + int gdb_num = group / EXT4_DESC_PER_BLOCK(sb); + int gdb_num_end = ((group + flex_gd->count - 1) / + EXT4_DESC_PER_BLOCK(sb)); + update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es, sizeof(struct ext4_super_block)); - for (i = 0; i < flex_gd->count; i++, group++) { + for (; gdb_num <= gdb_num_end; gdb_num++) { struct buffer_head *gdb_bh; - int gdb_num; - gdb_num = group / EXT4_BLOCKS_PER_GROUP(sb); + gdb_bh = sbi->s_group_desc[gdb_num]; update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data, gdb_bh->b_size);
--
1.7.12.rc0.22.gcdd159b