[bug report] ext4: Set flags on quota files directly

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

Hello Jan Kara,

The patch 957153fce8d2: "ext4: Set flags on quota files directly"
from Apr 6, 2017, leads to the following Smatch static checker
warning:

	fs/ext4/super.c:6779 ext4_quota_on()
	warn: missing error code here? 'IS_ERR()' failed. 'err' = '0'

fs/ext4/super.c
    6761 
    6762         lockdep_set_quota_inode(path->dentry->d_inode, I_DATA_SEM_QUOTA);
    6763         err = dquot_quota_on(sb, type, format_id, path);
    6764         if (err) {
    6765                 lockdep_set_quota_inode(path->dentry->d_inode,
    6766                                              I_DATA_SEM_NORMAL);
    6767         } else {
    6768                 struct inode *inode = d_inode(path->dentry);
    6769                 handle_t *handle;
    6770 
    6771                 /*
    6772                  * Set inode flags to prevent userspace from messing with quota
    6773                  * files. If this fails, we return success anyway since quotas
    6774                  * are already enabled and this is not a hard failure.
    6775                  */
    6776                 inode_lock(inode);
    6777                 handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
    6778                 if (IS_ERR(handle))
--> 6779                         goto unlock_inode;

This should set "err = PTR_ERR(handle)" right?

    6780                 EXT4_I(inode)->i_flags |= EXT4_NOATIME_FL | EXT4_IMMUTABLE_FL;
    6781                 inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
    6782                                 S_NOATIME | S_IMMUTABLE);
    6783                 err = ext4_mark_inode_dirty(handle, inode);
    6784                 ext4_journal_stop(handle);
    6785         unlock_inode:
    6786                 inode_unlock(inode);
    6787         }
    6788         return err;
    6789 }

regards,
dan carpenter