lustre/llite: simplify dentry revalidate

Lustre client dentry validation is protected by LDLM lock, so
any time a dentry is found, it's valid and no need to revalidate
from MDS, and even it does, there is race that it may be
invalidated after revalidation is finished.
Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-on: http://review.whamcloud.com/7475
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3544Reviewed-by: Peng Tao <bergwolf@gmail.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/lustre/lustre_idl.h

@@ -2112,7 +2112,7 @@ extern void lustre_swab_generic_32s (__u32 *val);
 #define DISP_LOOKUP_POS      0x00000008
 #define DISP_OPEN_CREATE     0x00000010
 #define DISP_OPEN_OPEN       0x00000020
-#define DISP_ENQ_COMPLETE    0x00400000
+#define DISP_ENQ_COMPLETE    0x00400000		/* obsolete and unused */
 #define DISP_ENQ_OPEN_REF    0x00800000
 #define DISP_ENQ_CREATE_REF  0x01000000
 #define DISP_OPEN_LOCK       0x02000000

drivers/staging/lustre/lustre/llite/file.c

@@ -446,8 +446,7 @@ static int ll_intent_file_open(struct file *file, void *lmm,
 				 itp, NULL);
 
 out:
-	ptlrpc_req_finished(itp->d.lustre.it_data);
-	it_clear_disposition(itp, DISP_ENQ_COMPLETE);
+	ptlrpc_req_finished(req);
 	ll_intent_drop_lock(itp);
 
 	return rc;
@@ -815,10 +814,7 @@ struct obd_client_handle *ll_lease_open(struct inode *inode, struct file *file,
 	 * doesn't deal with openhandle, so normal openhandle will be leaked. */
 				LDLM_FL_NO_LRU | LDLM_FL_EXCL);
 	ll_finish_md_op_data(op_data);
-	if (req != NULL) {
-		ptlrpc_req_finished(req);
-		it_clear_disposition(&it, DISP_ENQ_COMPLETE);
-	}
+	ptlrpc_req_finished(req);
 	if (rc < 0)
 		GOTO(out_release_it, rc);
 

drivers/staging/lustre/lustre/llite/llite_internal.h

@@ -1309,7 +1309,7 @@ ll_statahead_mark(struct inode *dir, struct dentry *dentry)
 }
 
 static inline int
-ll_need_statahead(struct inode *dir, struct dentry *dentryp)
+d_need_statahead(struct inode *dir, struct dentry *dentryp)
 {
 	struct ll_inode_info  *lli;
 	struct ll_dentry_data *ldd;
@@ -1354,7 +1354,7 @@ ll_statahead_enter(struct inode *dir, struct dentry **dentryp, int only_unplug)
 {
 	int ret;
 
-	ret = ll_need_statahead(dir, *dentryp);
+	ret = d_need_statahead(dir, *dentryp);
 	if (ret <= 0)
 		return ret;
 

drivers/staging/lustre/lustre/lmv/lmv_intent.c

@@ -119,7 +119,6 @@ static int lmv_intent_remote(struct obd_export *exp, void *lmm,
 	CDEBUG(D_INODE, "REMOTE_INTENT with fid="DFID" -> mds #%d\n",
 	       PFID(&body->fid1), tgt->ltd_idx);
 
-	it->d.lustre.it_disposition &= ~DISP_ENQ_COMPLETE;
 	rc = md_intent_lock(tgt->ltd_exp, op_data, lmm, lmmsize, it,
 			    flags, &req, cb_blocking, extra_lock_flags);
 	if (rc)

drivers/staging/lustre/lustre/lmv/lmv_obd.c

@@ -1744,7 +1744,6 @@ lmv_enqueue_remote(struct obd_export *exp, struct ldlm_enqueue_info *einfo,
 	it->d.lustre.it_data = NULL;
 	fid1 = body->fid1;
 
-	it->d.lustre.it_disposition &= ~DISP_ENQ_COMPLETE;
 	ptlrpc_req_finished(req);
 
 	tgt = lmv_find_target(lmv, &fid1);

drivers/staging/lustre/lustre/mdc/mdc_locks.c

@@ -968,7 +968,6 @@ static int mdc_finish_intent_lock(struct obd_export *exp,
 	if (fid_is_sane(&op_data->op_fid2) &&
 	    it->it_create_mode & M_CHECK_STALE &&
 	    it->it_op != IT_GETATTR) {
-		it_set_disposition(it, DISP_ENQ_COMPLETE);
 
 		/* Also: did we find the same inode? */
 		/* sever can return one of two fids:
@@ -1139,6 +1138,12 @@ int mdc_intent_lock(struct obd_export *exp, struct md_op_data *op_data,
 		    ldlm_blocking_callback cb_blocking,
 		    __u64 extra_lock_flags)
 {
+	struct ldlm_enqueue_info einfo = {
+		.ei_type	= LDLM_IBITS,
+		.ei_mode	= it_to_lock_mode(it),
+		.ei_cb_bl	= cb_blocking,
+		.ei_cb_cp	= ldlm_completion_ast,
+	};
 	struct lustre_handle lockh;
 	int rc = 0;
 
@@ -1164,42 +1169,19 @@ int mdc_intent_lock(struct obd_export *exp, struct md_op_data *op_data,
 			return rc;
 	}
 
-	/* lookup_it may be called only after revalidate_it has run, because
-	 * revalidate_it cannot return errors, only zero.  Returning zero causes
-	 * this call to lookup, which *can* return an error.
-	 *
-	 * We only want to execute the request associated with the intent one
-	 * time, however, so don't send the request again.  Instead, skip past
-	 * this and use the request from revalidate.  In this case, revalidate
-	 * never dropped its reference, so the refcounts are all OK */
-	if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
-		struct ldlm_enqueue_info einfo = {
-			.ei_type	= LDLM_IBITS,
-			.ei_mode	= it_to_lock_mode(it),
-			.ei_cb_bl	= cb_blocking,
-			.ei_cb_cp	= ldlm_completion_ast,
-		};
-
-		/* For case if upper layer did not alloc fid, do it now. */
-		if (!fid_is_sane(&op_data->op_fid2) && it->it_op & IT_CREAT) {
-			rc = mdc_fid_alloc(exp, &op_data->op_fid2, op_data);
-			if (rc < 0) {
-				CERROR("Can't alloc new fid, rc %d\n", rc);
-				return rc;
-			}
-		}
-		rc = mdc_enqueue(exp, &einfo, it, op_data, &lockh,
-				 lmm, lmmsize, NULL, extra_lock_flags);
-		if (rc < 0)
+	/* For case if upper layer did not alloc fid, do it now. */
+	if (!fid_is_sane(&op_data->op_fid2) && it->it_op & IT_CREAT) {
+		rc = mdc_fid_alloc(exp, &op_data->op_fid2, op_data);
+		if (rc < 0) {
+			CERROR("Can't alloc new fid, rc %d\n", rc);
 			return rc;
-	} else if (!fid_is_sane(&op_data->op_fid2) ||
-		   !(it->it_create_mode & M_CHECK_STALE)) {
-		/* DISP_ENQ_COMPLETE set means there is extra reference on
-		 * request referenced from this intent, saved for subsequent
-		 * lookup.  This path is executed when we proceed to this
-		 * lookup, so we clear DISP_ENQ_COMPLETE */
-		it_clear_disposition(it, DISP_ENQ_COMPLETE);
+		}
 	}
+	rc = mdc_enqueue(exp, &einfo, it, op_data, &lockh, lmm, lmmsize, NULL,
+			 extra_lock_flags);
+	if (rc < 0)
+		return rc;
+
 	*reqp = it->d.lustre.it_data;
 	rc = mdc_finish_intent_lock(exp, *reqp, op_data, it, &lockh);
 	return rc;