Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 82 insertions, 23 deletions

diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index b1ecc6f97ade..3631783b2b53 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -43,6 +43,17 @@
 
 
 /*
+ * Define xfs inode iolock lockdep classes. We need to ensure that all active
+ * inodes are considered the same for lockdep purposes, including inodes that
+ * are recycled through the XFS_IRECLAIMABLE state. This is the the only way to
+ * guarantee the locks are considered the same when there are multiple lock
+ * initialisation siteѕ. Also, define a reclaimable inode class so it is
+ * obvious in lockdep reports which class the report is against.
+ */
+static struct lock_class_key xfs_iolock_active;
+struct lock_class_key xfs_iolock_reclaimable;
+
+/*
  * Allocate and initialise an xfs_inode.
  */
 STATIC struct xfs_inode *
@@ -69,8 +80,11 @@ xfs_inode_alloc(
         ASSERT(atomic_read(&ip->i_pincount) == 0);
         ASSERT(!spin_is_locked(&ip->i_flags_lock));
         ASSERT(completion_done(&ip->i_flush));
+        ASSERT(ip->i_ino == 0);
 
         mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+        lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
+                        &xfs_iolock_active, "xfs_iolock_active");
 
         /* initialise the xfs inode */
         ip->i_ino = ino;
@@ -85,12 +99,20 @@ xfs_inode_alloc(
         ip->i_size = 0;
         ip->i_new_size = 0;
 
-        /* prevent anyone from using this yet */
-        VFS_I(ip)->i_state = I_NEW;
-
         return ip;
 }
 
+STATIC void
+xfs_inode_free_callback(
+        struct rcu_head         *head)
+{
+        struct inode            *inode = container_of(head, struct inode, i_rcu);
+        struct xfs_inode        *ip = XFS_I(inode);
+
+        INIT_LIST_HEAD(&inode->i_dentry);
+        kmem_zone_free(xfs_inode_zone, ip);
+}
+
 void
 xfs_inode_free(
         struct xfs_inode        *ip)
@@ -134,7 +156,18 @@ xfs_inode_free(
         ASSERT(!spin_is_locked(&ip->i_flags_lock));
         ASSERT(completion_done(&ip->i_flush));
 
-        kmem_zone_free(xfs_inode_zone, ip);
+        /*
+         * Because we use RCU freeing we need to ensure the inode always
+         * appears to be reclaimed with an invalid inode number when in the
+         * free state. The ip->i_flags_lock provides the barrier against lookup
+         * races.
+         */
+        spin_lock(&ip->i_flags_lock);
+        ip->i_flags = XFS_IRECLAIM;
+        ip->i_ino = 0;
+        spin_unlock(&ip->i_flags_lock);
+
+        call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
 }
 
 /*
@@ -144,14 +177,29 @@ static int
 xfs_iget_cache_hit(
         struct xfs_perag        *pag,
         struct xfs_inode        *ip,
+        xfs_ino_t               ino,
         int                     flags,
-        int                     lock_flags) __releases(pag->pag_ici_lock)
+        int                     lock_flags) __releases(RCU)
 {
         struct inode            *inode = VFS_I(ip);
         struct xfs_mount        *mp = ip->i_mount;
         int                     error;
 
+        /*
+         * check for re-use of an inode within an RCU grace period due to the
+         * radix tree nodes not being updated yet. We monitor for this by
+         * setting the inode number to zero before freeing the inode structure.
+         * If the inode has been reallocated and set up, then the inode number
+         * will not match, so check for that, too.
+         */
         spin_lock(&ip->i_flags_lock);
+        if (ip->i_ino != ino) {
+                trace_xfs_iget_skip(ip);
+                XFS_STATS_INC(xs_ig_frecycle);
+                error = EAGAIN;
+                goto out_error;
+        }
+
 
         /*
          * If we are racing with another cache hit that is currently
@@ -194,7 +242,7 @@ xfs_iget_cache_hit(
                 ip->i_flags |= XFS_IRECLAIM;
 
                 spin_unlock(&ip->i_flags_lock);
-                read_unlock(&pag->pag_ici_lock);
+                rcu_read_unlock();
 
                 error = -inode_init_always(mp->m_super, inode);
                 if (error) {
@@ -202,24 +250,35 @@ xfs_iget_cache_hit(
                          * Re-initializing the inode failed, and we are in deep
                          * trouble.  Try to re-add it to the reclaim list.
                          */
-                        read_lock(&pag->pag_ici_lock);
+                        rcu_read_lock();
                         spin_lock(&ip->i_flags_lock);
 
-                        ip->i_flags &= ~XFS_INEW;
-                        ip->i_flags |= XFS_IRECLAIMABLE;
-                        __xfs_inode_set_reclaim_tag(pag, ip);
+                        ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
+                        ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
                         trace_xfs_iget_reclaim_fail(ip);
                         goto out_error;
                 }
 
-                write_lock(&pag->pag_ici_lock);
+                spin_lock(&pag->pag_ici_lock);
                 spin_lock(&ip->i_flags_lock);
-                ip->i_flags &= ~(XFS_IRECLAIMABLE | XFS_IRECLAIM);
+
+                /*
+                 * Clear the per-lifetime state in the inode as we are now
+                 * effectively a new inode and need to return to the initial
+                 * state before reuse occurs.
+                 */
+                ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
                 ip->i_flags |= XFS_INEW;
                 __xfs_inode_clear_reclaim_tag(mp, pag, ip);
                 inode->i_state = I_NEW;
+
+                ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
+                mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+                lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
+                                &xfs_iolock_active, "xfs_iolock_active");
+
                 spin_unlock(&ip->i_flags_lock);
-                write_unlock(&pag->pag_ici_lock);
+                spin_unlock(&pag->pag_ici_lock);
         } else {
                 /* If the VFS inode is being torn down, pause and try again. */
                 if (!igrab(inode)) {
@@ -230,7 +289,7 @@ xfs_iget_cache_hit(
 
                 /* We've got a live one. */
                 spin_unlock(&ip->i_flags_lock);
-                read_unlock(&pag->pag_ici_lock);
+                rcu_read_unlock();
                 trace_xfs_iget_hit(ip);
         }
 
@@ -244,7 +303,7 @@ xfs_iget_cache_hit(
 
 out_error:
         spin_unlock(&ip->i_flags_lock);
-        read_unlock(&pag->pag_ici_lock);
+        rcu_read_unlock();
         return error;
 }
 
@@ -297,7 +356,7 @@ xfs_iget_cache_miss(
                         BUG();
         }
 
-        write_lock(&pag->pag_ici_lock);
+        spin_lock(&pag->pag_ici_lock);
 
         /* insert the new inode */
         error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
@@ -312,14 +371,14 @@ xfs_iget_cache_miss(
         ip->i_udquot = ip->i_gdquot = NULL;
         xfs_iflags_set(ip, XFS_INEW);
 
-        write_unlock(&pag->pag_ici_lock);
+        spin_unlock(&pag->pag_ici_lock);
         radix_tree_preload_end();
 
         *ipp = ip;
         return 0;
 
 out_preload_end:
-        write_unlock(&pag->pag_ici_lock);
+        spin_unlock(&pag->pag_ici_lock);
         radix_tree_preload_end();
         if (lock_flags)
                 xfs_iunlock(ip, lock_flags);
@@ -365,8 +424,8 @@ xfs_iget(
         xfs_perag_t     *pag;
         xfs_agino_t     agino;
 
-        /* the radix tree exists only in inode capable AGs */
-        if (XFS_INO_TO_AGNO(mp, ino) >= mp->m_maxagi)
+        /* reject inode numbers outside existing AGs */
+        if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
                 return EINVAL;
 
         /* get the perag structure and ensure that it's inode capable */
@@ -375,15 +434,15 @@ xfs_iget(
 
 again:
         error = 0;
-        read_lock(&pag->pag_ici_lock);
+        rcu_read_lock();
         ip = radix_tree_lookup(&pag->pag_ici_root, agino);
 
         if (ip) {
-                error = xfs_iget_cache_hit(pag, ip, flags, lock_flags);
+                error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
                 if (error)
                         goto out_error_or_again;
         } else {
-                read_unlock(&pag->pag_ici_lock);
+                rcu_read_unlock();
                 XFS_STATS_INC(xs_ig_missed);
 
                 error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,