ext4: Remove i_mutex use from ext4_quota_write()

We don't need i_mutex in ext4_quota_write() because writes to quota file
are serialized by dqio_mutex anyway. Changes to quota files outside of quota
code are forbidded and enforced by NOATIME and IMMUTABLE bits.

Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ceebaf8..97938db 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4760,7 +4760,6 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
                return -EIO;
        }
 
-       mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
        bh = ext4_bread(handle, inode, blk, 1, &err);
        if (!bh)
                goto out;
@@ -4776,16 +4775,13 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
        err = ext4_handle_dirty_metadata(handle, NULL, bh);
        brelse(bh);
 out:
-       if (err) {
-               mutex_unlock(&inode->i_mutex);
+       if (err)
                return err;
-       }
        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);
        }
-       mutex_unlock(&inode->i_mutex);
        return len;
 }