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[PATCH 3/5] xfs: do not take the iolock in xfs_inactive

To: xfs@xxxxxxxxxxx
Subject: [PATCH 3/5] xfs: do not take the iolock in xfs_inactive
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Wed, 04 Jul 2012 11:13:31 -0400
Cc: sage@xxxxxxxxxxxx
References: <20120704151328.928543446@xxxxxxxxxxxxxxxxxxxxxx>
User-agent: quilt/0.48-1
An inode that enters xfs_inactive has been removed from all global
lists but the inode hash, and can't be recycled in xfs_iget before
it has been marked reclaimable.  Thus taking the iolock in here
is not nessecary at all, and given the amount of lockdep false
positives it has triggered already I'd rather remove the locking.

The only change outside of xfs_inactive is relaxing an assert in
xfs_itruncate_extents.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>

---
 fs/xfs/xfs_inode.c    |    4 +++-
 fs/xfs/xfs_vnodeops.c |   29 ++++++++++++-----------------
 2 files changed, 15 insertions(+), 18 deletions(-)

Index: xfs/fs/xfs/xfs_vnodeops.c
===================================================================
--- xfs.orig/fs/xfs/xfs_vnodeops.c      2012-07-04 09:51:01.347038413 +0200
+++ xfs/fs/xfs/xfs_vnodeops.c   2012-07-04 09:51:03.913705064 +0200
@@ -554,7 +554,7 @@ xfs_inactive(
                return VN_INACTIVE_CACHE;
        }
 
-       xfs_ilock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+       xfs_ilock(ip, XFS_ILOCK_EXCL);
        xfs_trans_ijoin(tp, ip, 0);
 
        if (S_ISLNK(ip->i_d.di_mode)) {
@@ -591,21 +591,24 @@ xfs_inactive(
                ASSERT(ip->i_d.di_forkoff != 0);
 
                error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
-               xfs_iunlock(ip, XFS_ILOCK_EXCL);
                if (error)
-                       goto error_unlock;
+                       goto out_unlock;
+
+               xfs_iunlock(ip, XFS_ILOCK_EXCL);
 
                error = xfs_attr_inactive(ip);
                if (error)
-                       goto error_unlock;
+                       goto out;
 
                tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
                error = xfs_trans_reserve(tp, 0,
                                          XFS_IFREE_LOG_RES(mp),
                                          0, XFS_TRANS_PERM_LOG_RES,
                                          XFS_INACTIVE_LOG_COUNT);
-               if (error)
-                       goto error_cancel;
+               if (error) {
+                       xfs_trans_cancel(tp, 0);
+                       goto out;
+               }
 
                xfs_ilock(ip, XFS_ILOCK_EXCL);
                xfs_trans_ijoin(tp, ip, 0);
@@ -658,21 +661,13 @@ xfs_inactive(
         * Release the dquots held by inode, if any.
         */
        xfs_qm_dqdetach(ip);
-       xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
-
+out_unlock:
+       xfs_iunlock(ip, XFS_ILOCK_EXCL);
 out:
        return VN_INACTIVE_CACHE;
 out_cancel:
        xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
-       xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
-       return VN_INACTIVE_CACHE;
-
-error_cancel:
-       ASSERT(XFS_FORCED_SHUTDOWN(mp));
-       xfs_trans_cancel(tp, 0);
-error_unlock:
-       xfs_iunlock(ip, XFS_IOLOCK_EXCL);
-       return VN_INACTIVE_CACHE;
+       goto out_unlock;
 }
 
 /*
Index: xfs/fs/xfs/xfs_inode.c
===================================================================
--- xfs.orig/fs/xfs/xfs_inode.c 2012-07-04 09:40:04.413709004 +0200
+++ xfs/fs/xfs/xfs_inode.c      2012-07-04 09:51:03.913705064 +0200
@@ -1123,7 +1123,9 @@ xfs_itruncate_extents(
        int                     error = 0;
        int                     done = 0;
 
-       ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
+       ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+       ASSERT(!atomic_read(&VFS_I(ip)->i_count) ||
+              xfs_isilocked(ip, XFS_IOLOCK_EXCL));
        ASSERT(new_size <= XFS_ISIZE(ip));
        ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
        ASSERT(ip->i_itemp != NULL);

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