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 <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index e25e99b..d0f5353 100644 (file)
--- 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
index 22546ad..35ff9fe 100644 (file)
--- 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 @@ out:
        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;
 }