staging/lustre/llite: fix 'data race condition' issues of lli_flags

Fix 'data race condition' defects found by Coverity version
6.5.0:
Data race condition (MISSING_LOCK)
Accessing variable without holding lock. Elsewhere,
this variable is accessed with lock held.

lli->lli_flags need to be protected by lli->lli_lock.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2744
Lustre-change: http://review.whamcloud.com/6571
Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/llite_lib.c

@@ -1189,7 +1189,9 @@ void ll_clear_inode(struct inode *inode)
 		LASSERT(lli->lli_opendir_pid == 0);
 	}
 
+	spin_lock(&lli->lli_lock);
 	ll_i2info(inode)->lli_flags &= ~LLIF_MDS_SIZE_LOCK;
+	spin_unlock(&lli->lli_lock);
 	md_null_inode(sbi->ll_md_exp, ll_inode2fid(inode));
 
 	LASSERT(!lli->lli_open_fd_write_count);
@@ -1756,7 +1758,9 @@ void ll_update_inode(struct inode *inode, struct lustre_md *md)
 					/* Use old size assignment to avoid
 					 * deadlock bz14138 & bz14326 */
 					i_size_write(inode, body->size);
+					spin_lock(&lli->lli_lock);
 					lli->lli_flags |= LLIF_MDS_SIZE_LOCK;
+					spin_unlock(&lli->lli_lock);
 				}
 				ldlm_lock_decref(&lockh, mode);
 			}

drivers/staging/lustre/lustre/llite/namei.c

@@ -275,8 +275,11 @@ int ll_md_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
 				CDEBUG(D_INODE, "invaliding layout %d.\n", rc);
 		}
 
-		if (bits & MDS_INODELOCK_UPDATE)
+		if (bits & MDS_INODELOCK_UPDATE) {
+			spin_lock(&lli->lli_lock);
 			lli->lli_flags &= ~LLIF_MDS_SIZE_LOCK;
+			spin_unlock(&lli->lli_lock);
+		}
 
 		if (S_ISDIR(inode->i_mode) &&
 		     (bits & MDS_INODELOCK_UPDATE)) {