[PATCH v3] xfs: fix the symbolic link assert in xfs_ifree

[Mark Tinguely]

On 06/13/13 21:17, Dave Chinner wrote:
> On Thu, Jun 13, 2013 at 12:04:49PM -0500, Mark Tinguely wrote:
>> Adding an extended attribute to a symbolic link can force that
>> link to an remote extent. xfs_inactive() incorrectly assumes
>> that any symbolic link small enough to be in the inode core
>> is incore, resulting in the remote extent to not be removed.
>> xfs_ifree() will assert on presence of this leaked remote extent.
>>
>> Signed-off-by: Mark Tinguely<tinguely at sgi.com>
> .....
>> +/*
>> + * xfs_inactive_symlink - free a symlink
>> + */
>> +int
>> +xfs_inactive_symlink(
>> +	struct xfs_inode	*ip,
>> +	struct xfs_trans	**tp)
>> +{
>> +	struct xfs_mount *mp = ip->i_mount;
>> +	xfs_fsize_t	pathlen;
>
> int will do here - it can't be more than MAXPATHLEN = 1024, and this
> gets rid of the casts in the error print.
>
>> +
>> +	trace_xfs_readlink(ip);
>
> trace_xfs_inactive_symlink, as you mentioned ;)

sigh, and I reverted the inactive and symlink in the trace below. sigh 
again.

>
>> +
>> +	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
>> +
>> +	if (XFS_FORCED_SHUTDOWN(mp))
>> +		return XFS_ERROR(EIO);
>> +
>> +	/*
>> +	 * Zero length symlinks _can_ exist.
>> +	 */
>> +	pathlen = ip->i_d.di_size;
>> +	if (!pathlen)
>> +		return 0;
>> +
>> +	if (pathlen<  0 || pathlen>  MAXPATHLEN) {
>> +		xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
>> +			 __func__, (unsigned long long) ip->i_ino,
>                                                         ^ whitespace
>> +			 (long long) pathlen);
>
> Can we change this to a hex-based inode number (much easier to read)
> and the pathlen cast can go away if you use an int. i.e.:
>
> 		xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
> 			 __func__, (unsigned long long)ip->i_ino, pathlen);
>
>

Both of the items above were stole directly from xfs_readlink().
Thought they should be consistent(ly wrong :) ).


>> +		ASSERT(0);
>> +		return XFS_ERROR(EFSCORRUPTED);
>> +	}
>> +
>> +	if (ip->i_df.if_flags&  XFS_IFINLINE) {
>> +		if (ip->i_df.if_bytes>  0)
>> +			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
>> +					  XFS_DATA_FORK);
>> +		ASSERT(ip->i_df.if_bytes == 0);
>> +		return 0;
>> +	}
>> +
>> +	/* remove the remote symlink */
>> +	return(xfs_inactive_symlink_rmt(ip, tp));
>
> And no () around xfs_inactive_symlink_rmt().

>
>> +}
>> Index: b/fs/xfs/xfs_symlink.h
>> ===================================================================
>> --- a/fs/xfs/xfs_symlink.h
>> +++ b/fs/xfs/xfs_symlink.h
>> @@ -60,7 +60,7 @@ extern const struct xfs_buf_ops xfs_syml
>>   int xfs_symlink(struct xfs_inode *dp, struct xfs_name *link_name,
>>   		const char *target_path, umode_t mode, struct xfs_inode **ipp);
>>   int xfs_readlink(struct xfs_inode *ip, char *link);
>> -int xfs_inactive_symlink_rmt(struct xfs_inode *ip, struct xfs_trans **tpp);
>> +int xfs_inactive_symlink(struct xfs_inode *ip, struct xfs_trans **tpp);
>>
>>   #endif /* __KERNEL__ */
>>   #endif /* __XFS_SYMLINK_H */
>> Index: b/fs/xfs/xfs_trace.h
>> ===================================================================
>> --- a/fs/xfs/xfs_trace.h
>> +++ b/fs/xfs/xfs_trace.h
>> @@ -594,6 +594,8 @@ DEFINE_INODE_EVENT(xfs_inode_set_eofbloc
>>   DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
>>   DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
>>
>> +DEFINE_INODE_EVENT(xfs_symlink_inactive);
>> +
>
> No need for the extra whitespace, just put it hard up against the
> other DEFINE_INODE_EVENT()s. Might be better to put it directly
> after the readlink trace definition.
>
> Cheers,
>
> Dave.

Thanks.

--Mark.