[XFS] Retry linux inode cacech lookup if we found a stale inode. This

fixes crashes under high nfs load

SGI-PV: 941429
SGI-Modid: xfs-linux:xfs-kern:197929a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

fs/xfs/xfs_iget.c

@@ -30,6 +30,8 @@
  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  */
 
+#include <linux/delay.h>
+
 #include "xfs.h"
 
 #include "xfs_macros.h"
@@ -507,14 +509,13 @@ xfs_iget(
 
 	XFS_STATS_INC(xs_ig_attempts);
 
+retry:
 	if ((inode = iget_locked(XFS_MTOVFS(mp)->vfs_super, ino))) {
 		bhv_desc_t	*bdp;
 		xfs_inode_t	*ip;
-		int		newnode;
 
 		vp = LINVFS_GET_VP(inode);
 		if (inode->i_state & I_NEW) {
-inode_allocate:
 			vn_initialize(inode);
 			error = xfs_iget_core(vp, mp, tp, ino, flags,
 					lock_flags, ipp, bno);
@@ -525,22 +526,25 @@ xfs_iget(
 				iput(inode);
 			}
 		} else {
-			if (is_bad_inode(inode)) {
+			/*
+			 * If the inode is not fully constructed due to
+			 * filehandle mistmatches wait for the inode to go
+			 * away and try again.
+			 *
+			 * iget_locked will call __wait_on_freeing_inode
+			 * to wait for the inode to go away.
+			 */
+			if (is_bad_inode(inode) ||
+			    ((bdp = vn_bhv_lookup(VN_BHV_HEAD(vp),
+						  &xfs_vnodeops)) == NULL)) {
 				iput(inode);
-				return EIO;
+				delay(1);
+				goto retry;
 			}
 
-			bdp = vn_bhv_lookup(VN_BHV_HEAD(vp), &xfs_vnodeops);
-			if (bdp == NULL) {
-				XFS_STATS_INC(xs_ig_dup);
-				goto inode_allocate;
-			}
 			ip = XFS_BHVTOI(bdp);
 			if (lock_flags != 0)
 				xfs_ilock(ip, lock_flags);
-			newnode = (ip->i_d.di_mode == 0);
-			if (newnode)
-				xfs_iocore_inode_reinit(ip);
 			XFS_STATS_INC(xs_ig_found);
 			*ipp = ip;
 			error = 0;