Re: [PATCH 3/3] xfs: push down inactive transaction mgmt for ifree

Brian Foster
2013-09-19T12:38:45Z

On 09/18/2013 07:06 PM, Dave Chinner wrote:
> On Wed, Sep 18, 2013 at 12:16:00PM -0400, Brian Foster wrote:
>> Push the inode free work performed during xfs_inactive() down into
>> a new xfs_inactive_ifree() helper. This clears xfs_inactive() from
>> all inode locking and transaction management more directly
>> associated with freeing the inode xattrs, extents and the inode
>> itself.
>>
>> Signed-off-by: Brian Foster <bfoster@redhat.com>
>> ---
>> fs/xfs/xfs_inode.c | 121 +++++++++++++++++++++++++++++++----------------------
>> 1 file changed, 71 insertions(+), 50 deletions(-)
>>
>> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
>> index 9416462..a6ed69d 100644
>> --- a/fs/xfs/xfs_inode.c
>> +++ b/fs/xfs/xfs_inode.c
>> @@ -1710,6 +1710,74 @@ error0:
>> }
>>
>> /*
>> + * xfs_inactive_ifree()
>> + *
>> + * Perform the inode free when an inode is unlinked.
>> + */
>> +STATIC int
>> +xfs_inactive_ifree(
>> + struct xfs_inode *ip)
>> +{
>> + xfs_bmap_free_t free_list;
>> + xfs_fsblock_t first_block;
>> + int committed;
>> + struct xfs_mount *mp = ip->i_mount;
>> + struct xfs_trans *tp;
>> + int error;
>> +
>> + tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
>> + error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ifree, 0, 0);
>> + if (error) {
>> + ASSERT(XFS_FORCED_SHUTDOWN(mp));
>> + xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES);
>> + return error;
>> + }
>> +
>> + xfs_ilock(ip, XFS_ILOCK_EXCL);
>> + xfs_trans_ijoin(tp, ip, 0);
>> +
>> + xfs_bmap_init(&free_list, &first_block);
>> + error = xfs_ifree(tp, ip, &free_list);
>> + if (error) {
>> + /*
>> + * If we fail to free the inode, shut down. The cancel
>> + * might do that, we need to make sure. Otherwise the
>> + * inode might be lost for a long time or forever.
>> + */
>> + if (!XFS_FORCED_SHUTDOWN(mp)) {
>> + xfs_notice(mp, "%s: xfs_ifree returned error %d",
>> + __func__, error);
>> + xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
>> + }
>> + xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> + xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
>> + return error;
>> + }
>> +
>> + /*
>> + * Credit the quota account(s). The inode is gone.
>> + */
>> + xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_ICOUNT, -1);
>> +
>> + /*
>> + * Just ignore errors at this point. There is nothing we can
>> + * do except to try to keep going. Make sure it's not a silent
>> + * error.
>> + */
>> + error = xfs_bmap_finish(&tp, &free_list, &committed);
>> + if (error)
>> + xfs_notice(mp, "%s: xfs_bmap_finish returned error %d",
>> + __func__, error);
>> + error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
>> + if (error)
>> + xfs_notice(mp, "%s: xfs_trans_commit returned error %d",
>> + __func__, error);
>> +
>> + xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> + return 0;
>> +}
>
> I suspect we can clean up the error handling here now, and make it
> look like the symlink remove inactive handle where we cancel bmaps
> and abort transactions and trigger shutdowns appropriately. I'd
> leave that to a separate patchset, though ;)
>

Hmm, well I follow what you mean as far as changing the code I think.
But what changed that makes this safe? Or are you suggesting to shutdown
on a bmap_finish/trans_commit failure instead of just "being noisy?"

(Regardless, a separate patchset sounds good..)

>> - __func__, error);
>> - }
>> + error = xfs_inactive_ifree(ip);
>> + if (error)
>> + goto out;
>>
>> /*
>> * Release the dquots held by inode, if any.
>> */
>> xfs_qm_dqdetach(ip);
>> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> out:
>> return VN_INACTIVE_CACHE;
>> }
>
> I think it's time to kill VN_INACTIVE_CACHE, as well. It's a
> hold-over from Irix, and it serves no purpose what-so-ever on
> Linux...
>

Ok, looks like a trivial patch to append to the series. In fact, there
appears to be no reason to return a value from xfs_inactive() at all
(along with the out label being unnecessary)... Thanks.

Brian

> Otherwise it looks good.
>
> Cheers,
>
> Dave.