1 files changed, 22 insertions, 25 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 17d2a471751e..d72c80dbfbb1 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2741,42 +2741,39 @@ xfs_iunpin(
 {
         ASSERT(atomic_read(&ip->i_pincount) > 0);
 
-        if (atomic_dec_and_test(&ip->i_pincount)) {
+        if (atomic_dec_and_lock(&ip->i_pincount, &ip->i_flags_lock)) {
+
                 /*
-                 * If the inode is currently being reclaimed, the
-                 * linux inode _and_ the xfs vnode may have been
-                 * freed so we cannot reference either of them safely.
-                 * Hence we should not try to do anything to them
-                 * if the xfs inode is currently in the reclaim
-                 * path.
+                 * If the inode is currently being reclaimed, the link between
+                 * the bhv_vnode and the xfs_inode will be broken after the
+                 * XFS_IRECLAIM* flag is set. Hence, if these flags are not
+                 * set, then we can move forward and mark the linux inode dirty
+                 * knowing that it is still valid as it won't freed until after
+                 * the bhv_vnode<->xfs_inode link is broken in xfs_reclaim. The
+                 * i_flags_lock is used to synchronise the setting of the
+                 * XFS_IRECLAIM* flags and the breaking of the link, and so we
+                 * can execute atomically w.r.t to reclaim by holding this lock
+                 * here.
                  *
-                 * However, we still need to issue the unpin wakeup
-                 * call as the inode reclaim may be blocked waiting for
-                 * the inode to become unpinned.
+                 * However, we still need to issue the unpin wakeup call as the
+                 * inode reclaim may be blocked waiting for the inode to become
+                 * unpinned.
                  */
-                struct inode *inode = NULL;
 
-                spin_lock(&ip->i_flags_lock);
                 if (!__xfs_iflags_test(ip, XFS_IRECLAIM|XFS_IRECLAIMABLE)) {
                         bhv_vnode_t     *vp = XFS_ITOV_NULL(ip);
+                        struct inode *inode = NULL;
+
+                        BUG_ON(vp == NULL);
+                        inode = vn_to_inode(vp);
+                        BUG_ON(inode->i_state & I_CLEAR);
 
                         /* make sync come back and flush this inode */
-                        if (vp) {
-                                inode = vn_to_inode(vp);
-
-                                if (!(inode->i_state &
-                                                (I_NEW|I_FREEING|I_CLEAR))) {
-                                        inode = igrab(inode);
-                                        if (inode)
-                                                mark_inode_dirty_sync(inode);
-                                } else
-                                        inode = NULL;
-                        }
+                        if (!(inode->i_state & (I_NEW|I_FREEING)))
+                                mark_inode_dirty_sync(inode);
                 }
                 spin_unlock(&ip->i_flags_lock);
                 wake_up(&ip->i_ipin_wait);
-                if (inode)
-                        iput(inode);
         }
 }