ext4: remove unnecessary [cm]time update of quota file

It is not necessary to update [cm]time of quota file on each quota file write and it wastes journal space and IO throughput with inode writes. So just remove the updating from ext4_quota_write() and only update times when quotas are being turned off. Userspace cannot get anything reliable from quota files while they are used by the kernel anyway. Signed-off-by: Jan Kara <[email protected]> Signed-off-by: "Theodore Ts'o" <[email protected]>
caferrari · Apr 4, 2011 · 21f9769 · 21f9769
1 parent 50f689a
commit 21f9769
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Showing 2 changed files with 16 additions and 4 deletions.
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
@@ -86,8 +86,8 @@
 
 #ifdef CONFIG_QUOTA
 /* Amount of blocks needed for quota update - we know that the structure was
- * allocated so we need to update only inode+data */
-#define EXT4_QUOTA_TRANS_BLOCKS(sb) (test_opt(sb, QUOTA) ? 2 : 0)
+ * allocated so we need to update only data block */
+#define EXT4_QUOTA_TRANS_BLOCKS(sb) (test_opt(sb, QUOTA) ? 1 : 0)
 /* Amount of blocks needed for quota insert/delete - we do some block writes
  * but inode, sb and group updates are done only once */
 #define EXT4_QUOTA_INIT_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_INIT_ALLOC*\

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
@@ -4614,11 +4614,24 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
 
 static int ext4_quota_off(struct super_block *sb, int type)
 {
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	handle_t *handle;
+
 	/* Force all delayed allocation blocks to be allocated.
 	 * Caller already holds s_umount sem */
 	if (test_opt(sb, DELALLOC))
 		sync_filesystem(sb);
 
+	/* Update modification times of quota files when userspace can
+	 * start looking at them */
+	handle = ext4_journal_start(inode, 1);
+	if (IS_ERR(handle))
+		goto out;
+	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	ext4_mark_inode_dirty(handle, inode);
+	ext4_journal_stop(handle);
+
+out:
 	return dquot_quota_off(sb, type);
 }
 
@@ -4714,9 +4727,8 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
 	if (inode->i_size < off + len) {
 		i_size_write(inode, off + len);
 		EXT4_I(inode)->i_disksize = inode->i_size;
+		ext4_mark_inode_dirty(handle, inode);
 	}
-	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-	ext4_mark_inode_dirty(handle, inode);
 	mutex_unlock(&inode->i_mutex);
 	return len;
 }