LU-5344 llite: lookup master inode by ilookup5_nowait

[fs/lustre-release.git] / lustre / llite / namei.c

diff --git a/lustre/llite/namei.c b/lustre/llite/namei.c
index d7c28c3..29e379e 100644 (file)
--- a/lustre/llite/namei.c
+++ b/lustre/llite/namei.c
@@ -288,8 +288,34 @@ int ll_md_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
                                hash = cl_fid_build_ino(&lli->lli_pfid,
                                        ll_need_32bit_api(ll_i2sbi(inode)));
 
                                hash = cl_fid_build_ino(&lli->lli_pfid,
                                        ll_need_32bit_api(ll_i2sbi(inode)));
 

-                               master_inode = ilookup5(inode->i_sb, hash,
-                                                       ll_test_inode_by_fid,
+                               /* Do not lookup the inode with ilookup5,
+                                * otherwise it will cause dead lock,
+                                *
+                                * 1. Client1 send chmod req to the MDT0, then
+                                * on MDT0, it enqueues master and all of its
+                                * slaves lock, (mdt_attr_set() ->
+                                * mdt_lock_slaves()), after gets master and
+                                * stripe0 lock, it will send the enqueue req
+                                * (for stripe1) to MDT1, then MDT1 finds the
+                                * lock has been granted to client2. Then MDT1
+                                * sends blocking ast to client2.
+                                *
+                                * 2. At the same time, client2 tries to unlink
+                                * the striped dir (rm -rf striped_dir), and
+                                * during lookup, it will hold the master inode
+                                * of the striped directory, whose inode state
+                                * is NEW, then tries to revalidate all of its
+                                * slaves, (ll_prep_inode()->ll_iget()->
+                                * ll_read_inode2()-> ll_update_inode().). And
+                                * it will be blocked on the server side because
+                                * of 1.
+                                *
+                                * 3. Then the client get the blocking_ast req,
+                                * cancel the lock, but being blocked if using
+                                * ->ilookup5()), because master inode state is
+                                *  NEW. */
+                               master_inode = ilookup5_nowait(inode->i_sb,
+                                                   hash, ll_test_inode_by_fid,

                                                        (void *)&lli->lli_pfid);
                                if (master_inode != NULL &&
                                        !IS_ERR(master_inode)) {
                                                        (void *)&lli->lli_pfid);
                                if (master_inode != NULL &&
                                        !IS_ERR(master_inode)) {