+
+int ll_layout_conf(struct inode *inode, const struct cl_object_conf *conf)
+{
+ struct ll_inode_info *lli = ll_i2info(inode);
+ struct cl_env_nest nest;
+ struct lu_env *env;
+ int result;
+ ENTRY;
+
+ if (lli->lli_clob == NULL)
+ RETURN(0);
+
+ env = cl_env_nested_get(&nest);
+ if (IS_ERR(env))
+ RETURN(PTR_ERR(env));
+
+ result = cl_conf_set(env, lli->lli_clob, conf);
+ cl_env_nested_put(&nest, env);
+
+ if (conf->coc_opc == OBJECT_CONF_SET) {
+ struct ldlm_lock *lock = conf->coc_lock;
+
+ LASSERT(lock != NULL);
+ LASSERT(ldlm_has_layout(lock));
+ if (result == 0) {
+ /* it can only be allowed to match after layout is
+ * applied to inode otherwise false layout would be
+ * seen. Applying layout shoud happen before dropping
+ * the intent lock. */
+ ldlm_lock_allow_match(lock);
+ }
+ }
+ RETURN(result);
+}
+
+/**
+ * Apply the layout to the inode. Layout lock is held and will be released
+ * in this function.
+ */
+static int ll_layout_lock_set(struct lustre_handle *lockh, ldlm_mode_t mode,
+ struct inode *inode, __u32 *gen, bool reconf)
+{
+ struct ll_inode_info *lli = ll_i2info(inode);
+ struct ll_sb_info *sbi = ll_i2sbi(inode);
+ struct ldlm_lock *lock;
+ struct lustre_md md = { NULL };
+ struct cl_object_conf conf;
+ int rc = 0;
+ bool lvb_ready;
+ ENTRY;
+
+ LASSERT(lustre_handle_is_used(lockh));
+
+ lock = ldlm_handle2lock(lockh);
+ LASSERT(lock != NULL);
+ LASSERT(ldlm_has_layout(lock));
+
+ LDLM_DEBUG(lock, "File %p/"DFID" being reconfigured: %d.\n",
+ inode, PFID(&lli->lli_fid), reconf);
+
+ lock_res_and_lock(lock);
+ lvb_ready = !!(lock->l_flags & LDLM_FL_LVB_READY);
+ unlock_res_and_lock(lock);
+ /* checking lvb_ready is racy but this is okay. The worst case is
+ * that multi processes may configure the file on the same time. */
+ if (lvb_ready || !reconf) {
+ LDLM_LOCK_PUT(lock);
+
+ rc = -ENODATA;
+ if (lvb_ready) {
+ /* layout_gen must be valid if layout lock is not
+ * cancelled and stripe has already set */
+ *gen = lli->lli_layout_gen;
+ rc = 0;
+ }
+ ldlm_lock_decref(lockh, mode);
+ RETURN(rc);
+ }
+
+ /* for layout lock, lmm is returned in lock's lvb.
+ * lvb_data is immutable if the lock is held so it's safe to access it
+ * without res lock. See the description in ldlm_lock_decref_internal()
+ * for the condition to free lvb_data of layout lock */
+ if (lock->l_lvb_data != NULL) {
+ rc = obd_unpackmd(sbi->ll_dt_exp, &md.lsm,
+ lock->l_lvb_data, lock->l_lvb_len);
+ if (rc >= 0) {
+ *gen = LL_LAYOUT_GEN_EMPTY;
+ if (md.lsm != NULL)
+ *gen = md.lsm->lsm_layout_gen;
+ rc = 0;
+ } else {
+ CERROR("%s: file "DFID" unpackmd error: %d\n",
+ ll_get_fsname(inode->i_sb, NULL, 0),
+ PFID(&lli->lli_fid), rc);
+ }
+ }
+ if (rc < 0) {
+ LDLM_LOCK_PUT(lock);
+ ldlm_lock_decref(lockh, mode);
+ RETURN(rc);
+ }
+
+ /* set layout to file. Unlikely this will fail as old layout was
+ * surely eliminated */
+ memset(&conf, 0, sizeof conf);
+ conf.coc_opc = OBJECT_CONF_SET;
+ conf.coc_inode = inode;
+ conf.coc_lock = lock;
+ conf.u.coc_md = &md;
+ rc = ll_layout_conf(inode, &conf);
+ LDLM_LOCK_PUT(lock);
+
+ ldlm_lock_decref(lockh, mode);
+
+ if (md.lsm != NULL)
+ obd_free_memmd(sbi->ll_dt_exp, &md.lsm);
+
+ /* wait for IO to complete if it's still being used. */
+ if (rc == -EBUSY) {
+ CDEBUG(D_INODE, "%s: %p/"DFID" wait for layout reconf.\n",
+ ll_get_fsname(inode->i_sb, NULL, 0),
+ inode, PFID(&lli->lli_fid));
+
+ memset(&conf, 0, sizeof conf);
+ conf.coc_opc = OBJECT_CONF_WAIT;
+ conf.coc_inode = inode;
+ rc = ll_layout_conf(inode, &conf);
+ if (rc == 0)
+ rc = -EAGAIN;
+
+ CDEBUG(D_INODE, "file: "DFID" waiting layout return: %d.\n",
+ PFID(&lli->lli_fid), rc);
+ }
+
+ RETURN(rc);
+}
+
+/**
+ * This function checks if there exists a LAYOUT lock on the client side,
+ * or enqueues it if it doesn't have one in cache.
+ *
+ * This function will not hold layout lock so it may be revoked any time after
+ * this function returns. Any operations depend on layout should be redone
+ * in that case.
+ *
+ * This function should be called before lov_io_init() to get an uptodate
+ * layout version, the caller should save the version number and after IO
+ * is finished, this function should be called again to verify that layout
+ * is not changed during IO time.
+ */
+int ll_layout_refresh(struct inode *inode, __u32 *gen)
+{
+ struct ll_inode_info *lli = ll_i2info(inode);
+ struct ll_sb_info *sbi = ll_i2sbi(inode);
+ struct md_op_data *op_data;
+ struct lookup_intent it;
+ struct lustre_handle lockh;
+ ldlm_mode_t mode;
+ struct ldlm_enqueue_info einfo = { .ei_type = LDLM_IBITS,
+ .ei_mode = LCK_CR,
+ .ei_cb_bl = ll_md_blocking_ast,
+ .ei_cb_cp = ldlm_completion_ast,
+ .ei_cbdata = NULL };
+ int rc;
+ ENTRY;
+
+ *gen = LL_LAYOUT_GEN_NONE;
+ if (!(sbi->ll_flags & LL_SBI_LAYOUT_LOCK))
+ RETURN(0);
+
+ /* sanity checks */
+ LASSERT(fid_is_sane(ll_inode2fid(inode)));
+ LASSERT(S_ISREG(inode->i_mode));
+
+ /* mostly layout lock is caching on the local side, so try to match
+ * it before grabbing layout lock mutex. */
+ mode = ll_take_md_lock(inode, MDS_INODELOCK_LAYOUT, &lockh, 0);
+ if (mode != 0) { /* hit cached lock */
+ rc = ll_layout_lock_set(&lockh, mode, inode, gen, false);
+ if (rc == 0)
+ RETURN(0);
+
+ /* better hold lli_layout_mutex to try again otherwise
+ * it will have starvation problem. */
+ }
+
+ /* take layout lock mutex to enqueue layout lock exclusively. */
+ mutex_lock(&lli->lli_layout_mutex);
+
+again:
+ /* try again. Maybe somebody else has done this. */
+ mode = ll_take_md_lock(inode, MDS_INODELOCK_LAYOUT, &lockh, 0);
+ if (mode != 0) { /* hit cached lock */
+ rc = ll_layout_lock_set(&lockh, mode, inode, gen, true);
+ if (rc == -EAGAIN)
+ goto again;
+
+ mutex_unlock(&lli->lli_layout_mutex);
+ RETURN(rc);
+ }
+
+ op_data = ll_prep_md_op_data(NULL, inode, inode, NULL,
+ 0, 0, LUSTRE_OPC_ANY, NULL);
+ if (IS_ERR(op_data)) {
+ mutex_unlock(&lli->lli_layout_mutex);
+ RETURN(PTR_ERR(op_data));
+ }
+
+ /* have to enqueue one */
+ memset(&it, 0, sizeof(it));
+ it.it_op = IT_LAYOUT;
+ lockh.cookie = 0ULL;
+
+ LDLM_DEBUG_NOLOCK("%s: requeue layout lock for file %p/"DFID".\n",
+ ll_get_fsname(inode->i_sb, NULL, 0), inode,
+ PFID(&lli->lli_fid));
+
+ rc = md_enqueue(sbi->ll_md_exp, &einfo, &it, op_data, &lockh,
+ NULL, 0, NULL, 0);
+ if (it.d.lustre.it_data != NULL)
+ ptlrpc_req_finished(it.d.lustre.it_data);
+ it.d.lustre.it_data = NULL;
+
+ ll_finish_md_op_data(op_data);
+
+ md_set_lock_data(sbi->ll_md_exp, &it.d.lustre.it_lock_handle, inode, NULL);
+
+ mode = it.d.lustre.it_lock_mode;
+ it.d.lustre.it_lock_mode = 0;
+ ll_intent_drop_lock(&it);
+
+ if (rc == 0) {
+ /* set lock data in case this is a new lock */
+ ll_set_lock_data(sbi->ll_md_exp, inode, &it, NULL);
+ rc = ll_layout_lock_set(&lockh, mode, inode, gen, true);
+ if (rc == -EAGAIN)
+ goto again;
+ }
+ mutex_unlock(&lli->lli_layout_mutex);
+
+ RETURN(rc);
+}