cleanup the inode reclaim path

Merge xfs_iextract and xfs_idestroy into xfs_ireclaim as they are never
called individually.  Also rewrite most comments in this area as they
were severly out of date.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>

1 files changed, 86 insertions, 42 deletions

diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index 27ec2417b852..f58e5e000fce 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -450,65 +450,109 @@ xfs_iput_new(
         IRELE(ip);
 }
 
-
 /*
- * This routine embodies the part of the reclaim code that pulls
- * the inode from the inode hash table and the mount structure's
- * inode list.
- * This should only be called from xfs_reclaim().
+ * This is called free all the memory associated with an inode.
+ * It must free the inode itself and any buffers allocated for
+ * if_extents/if_data and if_broot.  It must also free the lock
+ * associated with the inode.
+ *
+ * Note: because we don't initialise everything on reallocation out
+ * of the zone, we must ensure we nullify everything correctly before
+ * freeing the structure.
  */
 void
-xfs_ireclaim(xfs_inode_t *ip)
+xfs_ireclaim(
+        struct xfs_inode        *ip)
 {
-        /*
-         * Remove from old hash list and mount list.
-         */
-        XFS_STATS_INC(xs_ig_reclaims);
+        struct xfs_mount        *mp = ip->i_mount;
+        struct xfs_perag        *pag;
 
-        xfs_iextract(ip);
+        XFS_STATS_INC(xs_ig_reclaims);
 
         /*
-         * Here we do a spurious inode lock in order to coordinate with inode
-         * cache radix tree lookups.  This is because the lookup can reference
-         * the inodes in the cache without taking references.  We make that OK
-         * here by ensuring that we wait until the inode is unlocked after the
-         * lookup before we go ahead and free it.  We get both the ilock and
-         * the iolock because the code may need to drop the ilock one but will
-         * still hold the iolock.
+         * Remove the inode from the per-AG radix tree.  It doesn't matter
+         * if it was never added to it because radix_tree_delete can deal
+         * with that case just fine.
          */
-        xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
+        pag = xfs_get_perag(mp, ip->i_ino);
+        write_lock(&pag->pag_ici_lock);
+        radix_tree_delete(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino));
+        write_unlock(&pag->pag_ici_lock);
+        xfs_put_perag(mp, pag);
 
         /*
-         * Release dquots (and their references) if any. An inode may escape
-         * xfs_inactive and get here via vn_alloc->vn_reclaim path.
+         * Here we do an (almost) spurious inode lock in order to coordinate
+         * with inode cache radix tree lookups.  This is because the lookup
+         * can reference the inodes in the cache without taking references.
+         *
+         * We make that OK here by ensuring that we wait until the inode is
+         * unlocked after the lookup before we go ahead and free it.  We get
+         * both the ilock and the iolock because the code may need to drop the
+         * ilock one but will still hold the iolock.
          */
-        XFS_QM_DQDETACH(ip->i_mount, ip);
-
+        xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
         /*
-         * Free all memory associated with the inode.
+         * Release dquots (and their references) if any.
          */
+        XFS_QM_DQDETACH(ip->i_mount, ip);
         xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
-        xfs_idestroy(ip);
-}
 
-/*
- * This routine removes an about-to-be-destroyed inode from
- * all of the lists in which it is located with the exception
- * of the behavior chain.
- */
-void
-xfs_iextract(
-        xfs_inode_t     *ip)
-{
-        xfs_mount_t     *mp = ip->i_mount;
-        xfs_perag_t     *pag = xfs_get_perag(mp, ip->i_ino);
+        switch (ip->i_d.di_mode & S_IFMT) {
+        case S_IFREG:
+        case S_IFDIR:
+        case S_IFLNK:
+                xfs_idestroy_fork(ip, XFS_DATA_FORK);
+                break;
+        }
 
-        write_lock(&pag->pag_ici_lock);
-        radix_tree_delete(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino));
-        write_unlock(&pag->pag_ici_lock);
-        xfs_put_perag(mp, pag);
+        if (ip->i_afp)
+                xfs_idestroy_fork(ip, XFS_ATTR_FORK);
 
-        mp->m_ireclaims++;
+#ifdef XFS_INODE_TRACE
+        ktrace_free(ip->i_trace);
+#endif
+#ifdef XFS_BMAP_TRACE
+        ktrace_free(ip->i_xtrace);
+#endif
+#ifdef XFS_BTREE_TRACE
+        ktrace_free(ip->i_btrace);
+#endif
+#ifdef XFS_RW_TRACE
+        ktrace_free(ip->i_rwtrace);
+#endif
+#ifdef XFS_ILOCK_TRACE
+        ktrace_free(ip->i_lock_trace);
+#endif
+#ifdef XFS_DIR2_TRACE
+        ktrace_free(ip->i_dir_trace);
+#endif
+        if (ip->i_itemp) {
+                /*
+                 * Only if we are shutting down the fs will we see an
+                 * inode still in the AIL. If it is there, we should remove
+                 * it to prevent a use-after-free from occurring.
+                 */
+                xfs_log_item_t  *lip = &ip->i_itemp->ili_item;
+                struct xfs_ail  *ailp = lip->li_ailp;
+
+                ASSERT(((lip->li_flags & XFS_LI_IN_AIL) == 0) ||
+                                       XFS_FORCED_SHUTDOWN(ip->i_mount));
+                if (lip->li_flags & XFS_LI_IN_AIL) {
+                        spin_lock(&ailp->xa_lock);
+                        if (lip->li_flags & XFS_LI_IN_AIL)
+                                xfs_trans_ail_delete(ailp, lip);
+                        else
+                                spin_unlock(&ailp->xa_lock);
+                }
+                xfs_inode_item_destroy(ip);
+                ip->i_itemp = NULL;
+        }
+        /* asserts to verify all state is correct here */
+        ASSERT(atomic_read(&ip->i_iocount) == 0);
+        ASSERT(atomic_read(&ip->i_pincount) == 0);
+        ASSERT(!spin_is_locked(&ip->i_flags_lock));
+        ASSERT(completion_done(&ip->i_flush));
+        kmem_zone_free(xfs_inode_zone, ip);
 }
 
 /*