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Date: Fri, 19 Sep 2008 14:12:23 +1000
From: Timothy Shimmin <tes@sgi.com>
MIME-Version: 1.0
Subject: Re: [PATCH] Unlock inode before calling xfs_idestroy()
References: <48D3193C.6060201@sgi.com>
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To: lachlan@sgi.com
Cc: xfs-oss <xfs@oss.sgi.com>, xfs-dev <xfs-dev@sgi.com>

Lachlan McIlroy wrote:
> Lock debugging reported the ilock was being destroyed
> without being unlocked.
> 
> --- a/fs/xfs/xfs_iget.c    2008-09-19 13:03:57.000000000 +1000
> +++ b/fs/xfs/xfs_iget.c    2008-09-19 13:12:38.000000000 +1000
> @@ -214,6 +214,7 @@ finish_inode:
>         xfs_ilock(ip, lock_flags);
> 
>     if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
> +        xfs_iunlock(ip, lock_flags);
>         xfs_idestroy(ip);
>         xfs_put_perag(mp, pag);
>         return ENOENT;
> @@ -224,6 +225,7 @@ finish_inode:
>      * write spinlock.
>      */
>     if (radix_tree_preload(GFP_KERNEL)) {
> +        xfs_iunlock(ip, lock_flags);
>         xfs_idestroy(ip);
>         delay(1);
>         goto again;
> @@ -239,6 +241,7 @@ finish_inode:
>         BUG_ON(error != -EEXIST);
>         write_unlock(&pag->pag_ici_lock);
>         radix_tree_preload_end();
> +        xfs_iunlock(ip, lock_flags);
>         xfs_idestroy(ip);
>         XFS_STATS_INC(xs_ig_dup);
>         goto again;

I'm just wondering about the case where lock_flags==0
and the inode is not locked.
I think it would fail an assert in xfs_iunlock().


--Tim


	if (lock_flags)
		xfs_ilock(ip, lock_flags);

	if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
		xfs_iunlock(ip, lock_flags);
		xfs_idestroy(ip);
		xfs_put_perag(mp, pag);
		return ENOENT;
	}

void
xfs_iunlock(
        xfs_inode_t             *ip,
        uint                    lock_flags)
{
        /*
         * You can't set both SHARED and EXCL for the same lock,
         * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
         * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
         */
        ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
               (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
        ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
               (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
        ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_IUNLOCK_NONOTIFY |
                        XFS_LOCK_DEP_MASK)) == 0);
        ASSERT(lock_flags != 0);