/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/quotaops.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/security.h>

#define DEBUG_SUBSYSTEM S_LLITE

#include "../include/obd_support.h"
#include "../include/lustre_fid.h"
#include "../include/lustre_dlm.h"
#include "../include/lustre_ver.h"
#include "llite_internal.h"

static int ll_create_it(struct inode *dir, struct dentry *dentry,
                        struct lookup_intent *it);

/* called from iget5_locked->find_inode() under inode_hash_lock spinlock */
static int ll_test_inode(struct inode *inode, void *opaque)
{
        struct ll_inode_info *lli = ll_i2info(inode);
        struct lustre_md     *md = opaque;

        if (unlikely(!(md->body->mbo_valid & OBD_MD_FLID))) {
                CERROR("MDS body missing FID\n");
                return 0;
        }

        if (!lu_fid_eq(&lli->lli_fid, &md->body->mbo_fid1))
                return 0;

        return 1;
}

static int ll_set_inode(struct inode *inode, void *opaque)
{
        struct ll_inode_info *lli = ll_i2info(inode);
        struct mdt_body *body = ((struct lustre_md *)opaque)->body;

        if (unlikely(!(body->mbo_valid & OBD_MD_FLID))) {
                CERROR("MDS body missing FID\n");
                return -EINVAL;
        }

        lli->lli_fid = body->mbo_fid1;
        if (unlikely(!(body->mbo_valid & OBD_MD_FLTYPE))) {
                CERROR("Can not initialize inode " DFID
                       " without object type: valid = %#llx\n",
                       PFID(&lli->lli_fid), body->mbo_valid);
                return -EINVAL;
        }

        inode->i_mode = (inode->i_mode & ~S_IFMT) | (body->mbo_mode & S_IFMT);
        if (unlikely(inode->i_mode == 0)) {
                CERROR("Invalid inode " DFID " type\n", PFID(&lli->lli_fid));
                return -EINVAL;
        }

        ll_lli_init(lli);

        return 0;
}

/**
 * Get an inode by inode number(@hash), which is already instantiated by
 * the intent lookup).
 */
struct inode *ll_iget(struct super_block *sb, ino_t hash,
                      struct lustre_md *md)
{
        struct inode     *inode;
        int rc = 0;

        LASSERT(hash != 0);
        inode = iget5_locked(sb, hash, ll_test_inode, ll_set_inode, md);
        if (!inode)
                return ERR_PTR(-ENOMEM);

        if (inode->i_state & I_NEW) {
                rc = ll_read_inode2(inode, md);
                if (!rc && S_ISREG(inode->i_mode) &&
                    !ll_i2info(inode)->lli_clob)
                        rc = cl_file_inode_init(inode, md);

                if (rc) {
                        /*
                         * Let's clear directory lsm here, otherwise
                         * make_bad_inode() will reset the inode mode
                         * to regular, then ll_clear_inode will not
                         * be able to clear lsm_md
                         */
                        if (S_ISDIR(inode->i_mode))
                                ll_dir_clear_lsm_md(inode);
                        make_bad_inode(inode);
                        unlock_new_inode(inode);
                        iput(inode);
                        inode = ERR_PTR(rc);
                } else {
                        unlock_new_inode(inode);
                }
        } else if (!(inode->i_state & (I_FREEING | I_CLEAR))) {
                rc = ll_update_inode(inode, md);
                CDEBUG(D_VFSTRACE, "got inode: " DFID "(%p): rc = %d\n",
                       PFID(&md->body->mbo_fid1), inode, rc);
                if (rc) {
                        if (S_ISDIR(inode->i_mode))
                                ll_dir_clear_lsm_md(inode);
                        iput(inode);
                        inode = ERR_PTR(rc);
                }
        }
        return inode;
}

static void ll_invalidate_negative_children(struct inode *dir)
{
        struct dentry *dentry, *tmp_subdir;

        spin_lock(&dir->i_lock);
        hlist_for_each_entry(dentry, &dir->i_dentry, d_u.d_alias) {
                spin_lock(&dentry->d_lock);
                if (!list_empty(&dentry->d_subdirs)) {
                        struct dentry *child;

                        list_for_each_entry_safe(child, tmp_subdir,
                                                 &dentry->d_subdirs,
                                                 d_child) {
                                if (d_really_is_negative(child))
                                        d_lustre_invalidate(child, 1);
                        }
                }
                spin_unlock(&dentry->d_lock);
        }
        spin_unlock(&dir->i_lock);
}

int ll_test_inode_by_fid(struct inode *inode, void *opaque)
{
        return lu_fid_eq(&ll_i2info(inode)->lli_fid, opaque);
}

int ll_md_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
                       void *data, int flag)
{
        struct lustre_handle lockh;
        int rc;

        switch (flag) {
        case LDLM_CB_BLOCKING:
                ldlm_lock2handle(lock, &lockh);
                rc = ldlm_cli_cancel(&lockh, LCF_ASYNC);
                if (rc < 0) {
                        CDEBUG(D_INODE, "ldlm_cli_cancel: rc = %d\n", rc);
                        return rc;
                }
                break;
        case LDLM_CB_CANCELING: {
                struct inode *inode = ll_inode_from_resource_lock(lock);
                __u64 bits = lock->l_policy_data.l_inodebits.bits;

                /* Inode is set to lock->l_resource->lr_lvb_inode
                 * for mdc - bug 24555
                 */
                LASSERT(!lock->l_ast_data);

                if (!inode)
                        break;

                /* Invalidate all dentries associated with this inode */
                LASSERT(ldlm_is_canceling(lock));

                if (!fid_res_name_eq(ll_inode2fid(inode),
                                     &lock->l_resource->lr_name)) {
                        LDLM_ERROR(lock, "data mismatch with object " DFID "(%p)",
                                   PFID(ll_inode2fid(inode)), inode);
                        LBUG();
                }

                if (bits & MDS_INODELOCK_XATTR) {
                        if (S_ISDIR(inode->i_mode))
                                ll_i2info(inode)->lli_def_stripe_offset = -1;
                        ll_xattr_cache_destroy(inode);
                        bits &= ~MDS_INODELOCK_XATTR;
                }

                /* For OPEN locks we differentiate between lock modes
                 * LCK_CR, LCK_CW, LCK_PR - bug 22891
                 */
                if (bits & MDS_INODELOCK_OPEN)
                        ll_have_md_lock(inode, &bits, lock->l_req_mode);

                if (bits & MDS_INODELOCK_OPEN) {
                        fmode_t fmode;

                        switch (lock->l_req_mode) {
                        case LCK_CW:
                                fmode = FMODE_WRITE;
                                break;
                        case LCK_PR:
                                fmode = FMODE_EXEC;
                                break;
                        case LCK_CR:
                                fmode = FMODE_READ;
                                break;
                        default:
                                LDLM_ERROR(lock, "bad lock mode for OPEN lock");
                                LBUG();
                        }

                        ll_md_real_close(inode, fmode);
                }

                if (bits & (MDS_INODELOCK_LOOKUP | MDS_INODELOCK_UPDATE |
                            MDS_INODELOCK_LAYOUT | MDS_INODELOCK_PERM))
                        ll_have_md_lock(inode, &bits, LCK_MINMODE);

                if (bits & MDS_INODELOCK_LAYOUT) {
                        struct cl_object_conf conf = {
                                .coc_opc = OBJECT_CONF_INVALIDATE,
                                .coc_inode = inode,
                        };

                        rc = ll_layout_conf(inode, &conf);
                        if (rc < 0)
                                CDEBUG(D_INODE, "cannot invalidate layout of "
                                       DFID ": rc = %d\n",
                                       PFID(ll_inode2fid(inode)), rc);
                }

                if (bits & MDS_INODELOCK_UPDATE) {
                        struct ll_inode_info *lli = ll_i2info(inode);

                        spin_lock(&lli->lli_lock);
                        LTIME_S(inode->i_mtime) = 0;
                        LTIME_S(inode->i_atime) = 0;
                        LTIME_S(inode->i_ctime) = 0;
                        spin_unlock(&lli->lli_lock);
                }

                if ((bits & MDS_INODELOCK_UPDATE) && S_ISDIR(inode->i_mode)) {
                        struct ll_inode_info *lli = ll_i2info(inode);

                        CDEBUG(D_INODE, "invalidating inode " DFID " lli = %p, pfid  = " DFID "\n",
                               PFID(ll_inode2fid(inode)), lli,
                               PFID(&lli->lli_pfid));

                        truncate_inode_pages(inode->i_mapping, 0);

                        if (unlikely(!fid_is_zero(&lli->lli_pfid))) {
                                struct inode *master_inode = NULL;
                                unsigned long hash;

                                /*
                                 * This is slave inode, since all of the child
                                 * dentry is connected on the master inode, so
                                 * we have to invalidate the negative children
                                 * on master inode
                                 */
                                CDEBUG(D_INODE, "Invalidate s" DFID " m" DFID "\n",
                                       PFID(ll_inode2fid(inode)),
                                       PFID(&lli->lli_pfid));

                                hash = cl_fid_build_ino(&lli->lli_pfid,
                                                        ll_need_32bit_api(ll_i2sbi(inode)));
                                /*
                                 * 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) {
                                        ll_invalidate_negative_children(master_inode);
                                        iput(master_inode);
                                }
                        } else {
                                ll_invalidate_negative_children(inode);
                        }
                }

                if ((bits & (MDS_INODELOCK_LOOKUP | MDS_INODELOCK_PERM)) &&
                    inode->i_sb->s_root &&
                    !is_root_inode(inode))
                        ll_invalidate_aliases(inode);

                iput(inode);
                break;
        }
        default:
                LBUG();
        }

        return 0;
}

__u32 ll_i2suppgid(struct inode *i)
{
        if (in_group_p(i->i_gid))
                return (__u32)from_kgid(&init_user_ns, i->i_gid);
        else
                return (__u32)(-1);
}

/* Pack the required supplementary groups into the supplied groups array.
 * If we don't need to use the groups from the target inode(s) then we
 * instead pack one or more groups from the user's supplementary group
 * array in case it might be useful.  Not needed if doing an MDS-side upcall.
 */
void ll_i2gids(__u32 *suppgids, struct inode *i1, struct inode *i2)
{
        LASSERT(i1);

        suppgids[0] = ll_i2suppgid(i1);

        if (i2)
                suppgids[1] = ll_i2suppgid(i2);
                else
                        suppgids[1] = -1;
}

/*
 * try to reuse three types of dentry:
 * 1. unhashed alias, this one is unhashed by d_invalidate (but it may be valid
 *    by concurrent .revalidate).
 * 2. INVALID alias (common case for no valid ldlm lock held, but this flag may
 *    be cleared by others calling d_lustre_revalidate).
 * 3. DISCONNECTED alias.
 */
static struct dentry *ll_find_alias(struct inode *inode, struct dentry *dentry)
{
        struct dentry *alias, *discon_alias, *invalid_alias;

        if (hlist_empty(&inode->i_dentry))
                return NULL;

        discon_alias = NULL;
        invalid_alias = NULL;

        spin_lock(&inode->i_lock);
        hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
                LASSERT(alias != dentry);

                spin_lock(&alias->d_lock);
                if ((alias->d_flags & DCACHE_DISCONNECTED) &&
                    S_ISDIR(inode->i_mode))
                        /* LASSERT(last_discon == NULL); LU-405, bz 20055 */
                        discon_alias = alias;
                else if (alias->d_parent == dentry->d_parent         &&
                         alias->d_name.hash == dentry->d_name.hash       &&
                         alias->d_name.len == dentry->d_name.len         &&
                         memcmp(alias->d_name.name, dentry->d_name.name,
                                dentry->d_name.len) == 0)
                        invalid_alias = alias;
                spin_unlock(&alias->d_lock);

                if (invalid_alias)
                        break;
        }
        alias = invalid_alias ?: discon_alias ?: NULL;
        if (alias) {
                spin_lock(&alias->d_lock);
                dget_dlock(alias);
                spin_unlock(&alias->d_lock);
        }
        spin_unlock(&inode->i_lock);

        return alias;
}

/*
 * Similar to d_splice_alias(), but lustre treats invalid alias
 * similar to DCACHE_DISCONNECTED, and tries to use it anyway.
 */
struct dentry *ll_splice_alias(struct inode *inode, struct dentry *de)
{
        if (inode) {
                struct dentry *new = ll_find_alias(inode, de);

                if (new) {
                        d_move(new, de);
                        iput(inode);
                        CDEBUG(D_DENTRY,
                               "Reuse dentry %p inode %p refc %d flags %#x\n",
                              new, d_inode(new), d_count(new), new->d_flags);
                        return new;
                }
        }
        d_add(de, inode);
        CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n",
               de, d_inode(de), d_count(de), de->d_flags);
        return de;
}

static int ll_lookup_it_finish(struct ptlrpc_request *request,
                               struct lookup_intent *it,
                               struct inode *parent, struct dentry **de)
{
        struct inode *inode = NULL;
        __u64 bits = 0;
        int rc = 0;
        struct dentry *alias;

        /* NB 1 request reference will be taken away by ll_intent_lock()
         * when I return
         */
        CDEBUG(D_DENTRY, "it %p it_disposition %x\n", it,
               it->it_disposition);
        if (!it_disposition(it, DISP_LOOKUP_NEG)) {
                rc = ll_prep_inode(&inode, request, (*de)->d_sb, it);
                if (rc)
                        return rc;

                ll_set_lock_data(ll_i2sbi(parent)->ll_md_exp, inode, it, &bits);

                /* We used to query real size from OSTs here, but actually
                 * this is not needed. For stat() calls size would be updated
                 * from subsequent do_revalidate()->ll_inode_revalidate_it() in
                 * 2.4 and
                 * vfs_getattr_it->ll_getattr()->ll_inode_revalidate_it() in 2.6
                 * Everybody else who needs correct file size would call
                 * ll_glimpse_size or some equivalent themselves anyway.
                 * Also see bug 7198.
                 */
        }

        alias = ll_splice_alias(inode, *de);
        if (IS_ERR(alias)) {
                rc = PTR_ERR(alias);
                goto out;
        }
        *de = alias;

        if (!it_disposition(it, DISP_LOOKUP_NEG)) {
                /* we have lookup look - unhide dentry */
                if (bits & MDS_INODELOCK_LOOKUP)
                        d_lustre_revalidate(*de);
        } else if (!it_disposition(it, DISP_OPEN_CREATE)) {
                /* If file created on server, don't depend on parent UPDATE
                 * lock to unhide it. It is left hidden and next lookup can
                 * find it in ll_splice_alias.
                 */
                /* Check that parent has UPDATE lock. */
                struct lookup_intent parent_it = {
                                        .it_op = IT_GETATTR,
                                        .it_lock_handle = 0 };
                struct lu_fid fid = ll_i2info(parent)->lli_fid;

                /* If it is striped directory, get the real stripe parent */
                if (unlikely(ll_i2info(parent)->lli_lsm_md)) {
                        rc = md_get_fid_from_lsm(ll_i2mdexp(parent),
                                                 ll_i2info(parent)->lli_lsm_md,
                                                 (*de)->d_name.name,
                                                 (*de)->d_name.len, &fid);
                        if (rc)
                                return rc;
                }

                if (md_revalidate_lock(ll_i2mdexp(parent), &parent_it, &fid,
                                       NULL)) {
                        d_lustre_revalidate(*de);
                        ll_intent_release(&parent_it);
                }
        }

out:
        if (rc != 0 && it->it_op & IT_OPEN)
                ll_open_cleanup((*de)->d_sb, request);

        return rc;
}

static struct dentry *ll_lookup_it(struct inode *parent, struct dentry *dentry,
                                   struct lookup_intent *it)
{
        struct lookup_intent lookup_it = { .it_op = IT_LOOKUP };
        struct dentry *save = dentry, *retval;
        struct ptlrpc_request *req = NULL;
        struct md_op_data *op_data = NULL;
        struct inode *inode;
        __u32 opc;
        int rc;

        if (dentry->d_name.len > ll_i2sbi(parent)->ll_namelen)
                return ERR_PTR(-ENAMETOOLONG);

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p),intent=%s\n",
               dentry, PFID(ll_inode2fid(parent)), parent, LL_IT2STR(it));

        if (d_mountpoint(dentry))
                CERROR("Tell Peter, lookup on mtpt, it %s\n", LL_IT2STR(it));

        if (!it || it->it_op == IT_GETXATTR)
                it = &lookup_it;

        if (it->it_op == IT_GETATTR && dentry_may_statahead(parent, dentry)) {
                rc = ll_statahead(parent, &dentry, 0);
                if (rc == 1) {
                        if (dentry == save)
                                retval = NULL;
                        else
                                retval = dentry;
                        goto out;
                }
        }

        if (it->it_op & IT_OPEN && it->it_flags & FMODE_WRITE &&
            dentry->d_sb->s_flags & MS_RDONLY)
                return ERR_PTR(-EROFS);

        if (it->it_op & IT_CREAT)
                opc = LUSTRE_OPC_CREATE;
        else
                opc = LUSTRE_OPC_ANY;

        op_data = ll_prep_md_op_data(NULL, parent, NULL, dentry->d_name.name,
                                     dentry->d_name.len, 0, opc, NULL);
        if (IS_ERR(op_data))
                return (void *)op_data;

        /* enforce umask if acl disabled or MDS doesn't support umask */
        if (!IS_POSIXACL(parent) || !exp_connect_umask(ll_i2mdexp(parent)))
                it->it_create_mode &= ~current_umask();

        rc = md_intent_lock(ll_i2mdexp(parent), op_data, it, &req,
                            &ll_md_blocking_ast, 0);
        /*
         * If the MDS allows the client to chgrp (CFS_SETGRP_PERM), but the
         * client does not know which suppgid should be sent to the MDS, or
         * some other(s) changed the target file's GID after this RPC sent
         * to the MDS with the suppgid as the original GID, then we should
         * try again with right suppgid.
         */
        if (rc == -EACCES && it->it_op & IT_OPEN &&
            it_disposition(it, DISP_OPEN_DENY)) {
                struct mdt_body *body;

                LASSERT(req);

                body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
                if (op_data->op_suppgids[0] == body->mbo_gid ||
                    op_data->op_suppgids[1] == body->mbo_gid ||
                    !in_group_p(make_kgid(&init_user_ns, body->mbo_gid))) {
                        retval = ERR_PTR(-EACCES);
                        goto out;
                }

                fid_zero(&op_data->op_fid2);
                op_data->op_suppgids[1] = body->mbo_gid;
                ptlrpc_req_finished(req);
                req = NULL;
                ll_intent_release(it);
                rc = md_intent_lock(ll_i2mdexp(parent), op_data, it, &req,
                                    ll_md_blocking_ast, 0);
        }

        if (rc < 0) {
                retval = ERR_PTR(rc);
                goto out;
        }

        rc = ll_lookup_it_finish(req, it, parent, &dentry);
        if (rc != 0) {
                ll_intent_release(it);
                retval = ERR_PTR(rc);
                goto out;
        }

        inode = d_inode(dentry);
        if ((it->it_op & IT_OPEN) && inode &&
            !S_ISREG(inode->i_mode) &&
            !S_ISDIR(inode->i_mode)) {
                ll_release_openhandle(inode, it);
        }
        ll_lookup_finish_locks(it, inode);

        if (dentry == save)
                retval = NULL;
        else
                retval = dentry;
out:
        if (op_data && !IS_ERR(op_data))
                ll_finish_md_op_data(op_data);

        ptlrpc_req_finished(req);
        return retval;
}

static struct dentry *ll_lookup_nd(struct inode *parent, struct dentry *dentry,
                                   unsigned int flags)
{
        struct lookup_intent *itp, it = { .it_op = IT_GETATTR };
        struct dentry *de;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p),flags=%u\n",
               dentry, PFID(ll_inode2fid(parent)), parent, flags);

        /* Optimize away (CREATE && !OPEN). Let .create handle the race.
         * but only if we have write permissions there, otherwise we need
         * to proceed with lookup. LU-4185
         */
        if ((flags & LOOKUP_CREATE) && !(flags & LOOKUP_OPEN) &&
            (inode_permission(parent, MAY_WRITE | MAY_EXEC) == 0))
                return NULL;

        if (flags & (LOOKUP_PARENT | LOOKUP_OPEN | LOOKUP_CREATE))
                itp = NULL;
        else
                itp = &it;
        de = ll_lookup_it(parent, dentry, itp);

        if (itp)
                ll_intent_release(itp);

        return de;
}

/*
 * For cached negative dentry and new dentry, handle lookup/create/open
 * together.
 */
static int ll_atomic_open(struct inode *dir, struct dentry *dentry,
                          struct file *file, unsigned int open_flags,
                          umode_t mode, int *opened)
{
        struct lookup_intent *it;
        struct dentry *de;
        int rc = 0;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p),file %p,open_flags %x,mode %x opened %d\n",
               dentry, PFID(ll_inode2fid(dir)), dir, file, open_flags, mode,
               *opened);

        /* Only negative dentries enter here */
        LASSERT(!d_inode(dentry));

        if (!d_in_lookup(dentry)) {
                /* A valid negative dentry that just passed revalidation,
                 * there's little point to try and open it server-side,
                 * even though there's a minuscle chance it might succeed.
                 * Either way it's a valid race to just return -ENOENT here.
                 */
                if (!(open_flags & O_CREAT))
                        return -ENOENT;

                /* Otherwise we just unhash it to be rehashed afresh via
                 * lookup if necessary
                 */
                d_drop(dentry);
        }

        it = kzalloc(sizeof(*it), GFP_NOFS);
        if (!it)
                return -ENOMEM;

        it->it_op = IT_OPEN;
        if (open_flags & O_CREAT)
                it->it_op |= IT_CREAT;
        it->it_create_mode = (mode & S_IALLUGO) | S_IFREG;
        it->it_flags = (open_flags & ~O_ACCMODE) | OPEN_FMODE(open_flags);
        it->it_flags &= ~MDS_OPEN_FL_INTERNAL;

        /* Dentry added to dcache tree in ll_lookup_it */
        de = ll_lookup_it(dir, dentry, it);
        if (IS_ERR(de))
                rc = PTR_ERR(de);
        else if (de)
                dentry = de;

        if (!rc) {
                if (it_disposition(it, DISP_OPEN_CREATE)) {
                        /* Dentry instantiated in ll_create_it. */
                        rc = ll_create_it(dir, dentry, it);
                        if (rc) {
                                /* We dget in ll_splice_alias. */
                                if (de)
                                        dput(de);
                                goto out_release;
                        }

                        *opened |= FILE_CREATED;
                }
                if (d_really_is_positive(dentry) && it_disposition(it, DISP_OPEN_OPEN)) {
                        /* Open dentry. */
                        if (S_ISFIFO(d_inode(dentry)->i_mode)) {
                                /* We cannot call open here as it might
                                 * deadlock. This case is unreachable in
                                 * practice because of OBD_CONNECT_NODEVOH.
                                 */
                                rc = finish_no_open(file, de);
                        } else {
                                file->private_data = it;
                                rc = finish_open(file, dentry, NULL, opened);
                                /* We dget in ll_splice_alias. finish_open takes
                                 * care of dget for fd open.
                                 */
                                if (de)
                                        dput(de);
                        }
                } else {
                        rc = finish_no_open(file, de);
                }
        }

out_release:
        ll_intent_release(it);
        kfree(it);

        return rc;
}

/* We depend on "mode" being set with the proper file type/umask by now */
static struct inode *ll_create_node(struct inode *dir, struct lookup_intent *it)
{
        struct inode *inode = NULL;
        struct ptlrpc_request *request = NULL;
        struct ll_sb_info *sbi = ll_i2sbi(dir);
        int rc;

        LASSERT(it && it->it_disposition);

        LASSERT(it_disposition(it, DISP_ENQ_CREATE_REF));
        request = it->it_request;
        it_clear_disposition(it, DISP_ENQ_CREATE_REF);
        rc = ll_prep_inode(&inode, request, dir->i_sb, it);
        if (rc) {
                inode = ERR_PTR(rc);
                goto out;
        }

        LASSERT(hlist_empty(&inode->i_dentry));

        /* We asked for a lock on the directory, but were granted a
         * lock on the inode.  Since we finally have an inode pointer,
         * stuff it in the lock.
         */
        CDEBUG(D_DLMTRACE, "setting l_ast_data to inode " DFID "(%p)\n",
               PFID(ll_inode2fid(dir)), inode);
        ll_set_lock_data(sbi->ll_md_exp, inode, it, NULL);
 out:
        ptlrpc_req_finished(request);
        return inode;
}

/*
 * By the time this is called, we already have created the directory cache
 * entry for the new file, but it is so far negative - it has no inode.
 *
 * We defer creating the OBD object(s) until open, to keep the intent and
 * non-intent code paths similar, and also because we do not have the MDS
 * inode number before calling ll_create_node() (which is needed for LOV),
 * so we would need to do yet another RPC to the MDS to store the LOV EA
 * data on the MDS.  If needed, we would pass the PACKED lmm as data and
 * lmm_size in datalen (the MDS still has code which will handle that).
 *
 * If the create succeeds, we fill in the inode information
 * with d_instantiate().
 */
static int ll_create_it(struct inode *dir, struct dentry *dentry,
                        struct lookup_intent *it)
{
        struct inode *inode;
        int rc = 0;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p), intent=%s\n",
               dentry, PFID(ll_inode2fid(dir)), dir, LL_IT2STR(it));

        rc = it_open_error(DISP_OPEN_CREATE, it);
        if (rc)
                return rc;

        inode = ll_create_node(dir, it);
        if (IS_ERR(inode))
                return PTR_ERR(inode);

        d_instantiate(dentry, inode);

        return ll_init_security(dentry, inode, dir);
}

void ll_update_times(struct ptlrpc_request *request, struct inode *inode)
{
        struct mdt_body *body = req_capsule_server_get(&request->rq_pill,
                                                       &RMF_MDT_BODY);

        LASSERT(body);
        if (body->mbo_valid & OBD_MD_FLMTIME &&
            body->mbo_mtime > LTIME_S(inode->i_mtime)) {
                CDEBUG(D_INODE, "setting fid " DFID " mtime from %lu to %llu\n",
                       PFID(ll_inode2fid(inode)), LTIME_S(inode->i_mtime),
                       body->mbo_mtime);
                LTIME_S(inode->i_mtime) = body->mbo_mtime;
        }
        if (body->mbo_valid & OBD_MD_FLCTIME &&
            body->mbo_ctime > LTIME_S(inode->i_ctime))
                LTIME_S(inode->i_ctime) = body->mbo_ctime;
}

static int ll_new_node(struct inode *dir, struct dentry *dentry,
                       const char *tgt, umode_t mode, int rdev,
                       __u32 opc)
{
        struct ptlrpc_request *request = NULL;
        struct md_op_data *op_data;
        struct inode *inode = NULL;
        struct ll_sb_info *sbi = ll_i2sbi(dir);
        int tgt_len = 0;
        int err;

        if (unlikely(tgt))
                tgt_len = strlen(tgt) + 1;
again:
        op_data = ll_prep_md_op_data(NULL, dir, NULL,
                                     dentry->d_name.name,
                                     dentry->d_name.len,
                                     0, opc, NULL);
        if (IS_ERR(op_data)) {
                err = PTR_ERR(op_data);
                goto err_exit;
        }

        err = md_create(sbi->ll_md_exp, op_data, tgt, tgt_len, mode,
                        from_kuid(&init_user_ns, current_fsuid()),
                        from_kgid(&init_user_ns, current_fsgid()),
                        cfs_curproc_cap_pack(), rdev, &request);
        ll_finish_md_op_data(op_data);
        if (err < 0 && err != -EREMOTE)
                goto err_exit;

        /*
         * If the client doesn't know where to create a subdirectory (or
         * in case of a race that sends the RPC to the wrong MDS), the
         * MDS will return -EREMOTE and the client will fetch the layout
         * of the directory, then create the directory on the right MDT.
         */
        if (unlikely(err == -EREMOTE)) {
                struct ll_inode_info *lli = ll_i2info(dir);
                struct lmv_user_md *lum;
                int lumsize, err2;

                ptlrpc_req_finished(request);
                request = NULL;

                err2 = ll_dir_getstripe(dir, (void **)&lum, &lumsize, &request,
                                        OBD_MD_DEFAULT_MEA);
                if (!err2) {
                        /* Update stripe_offset and retry */
                        lli->lli_def_stripe_offset = lum->lum_stripe_offset;
                } else if (err2 == -ENODATA &&
                           lli->lli_def_stripe_offset != -1) {
                        /*
                         * If there are no default stripe EA on the MDT, but the
                         * client has default stripe, then it probably means
                         * default stripe EA has just been deleted.
                         */
                        lli->lli_def_stripe_offset = -1;
                } else {
                        goto err_exit;
                }

                ptlrpc_req_finished(request);
                request = NULL;
                goto again;
        }

        ll_update_times(request, dir);

        err = ll_prep_inode(&inode, request, dir->i_sb, NULL);
        if (err)
                goto err_exit;

        d_instantiate(dentry, inode);

        err = ll_init_security(dentry, inode, dir);
err_exit:
        if (request)
                ptlrpc_req_finished(request);

        return err;
}

static int ll_mknod(struct inode *dir, struct dentry *dchild,
                    umode_t mode, dev_t rdev)
{
        int err;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p) mode %o dev %x\n",
               dchild, PFID(ll_inode2fid(dir)), dir, mode,
               old_encode_dev(rdev));

        if (!IS_POSIXACL(dir) || !exp_connect_umask(ll_i2mdexp(dir)))
                mode &= ~current_umask();

        switch (mode & S_IFMT) {
        case 0:
                mode |= S_IFREG; /* for mode = 0 case, fallthrough */
        case S_IFREG:
        case S_IFCHR:
        case S_IFBLK:
        case S_IFIFO:
        case S_IFSOCK:
                err = ll_new_node(dir, dchild, NULL, mode,
                                  old_encode_dev(rdev),
                                  LUSTRE_OPC_MKNOD);
                break;
        case S_IFDIR:
                err = -EPERM;
                break;
        default:
                err = -EINVAL;
        }

        if (!err)
                ll_stats_ops_tally(ll_i2sbi(dir), LPROC_LL_MKNOD, 1);

        return err;
}

/*
 * Plain create. Intent create is handled in atomic_open.
 */
static int ll_create_nd(struct inode *dir, struct dentry *dentry,
                        umode_t mode, bool want_excl)
{
        int rc;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p), flags=%u, excl=%d\n",
               dentry, PFID(ll_inode2fid(dir)), dir, mode, want_excl);

        rc = ll_mknod(dir, dentry, mode, 0);

        ll_stats_ops_tally(ll_i2sbi(dir), LPROC_LL_CREATE, 1);

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, unhashed %d\n",
               dentry, d_unhashed(dentry));

        return rc;
}

static int ll_unlink(struct inode *dir, struct dentry *dchild)
{
        struct ptlrpc_request *request = NULL;

        struct md_op_data *op_data;
        int rc;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd,dir=%lu/%u(%p)\n",
               dchild, dir->i_ino, dir->i_generation, dir);

        op_data = ll_prep_md_op_data(NULL, dir, NULL,
                                     dchild->d_name.name,
                                     dchild->d_name.len,
                                     0, LUSTRE_OPC_ANY, NULL);
        if (IS_ERR(op_data))
                return PTR_ERR(op_data);

        if (dchild->d_inode)
                op_data->op_fid3 = *ll_inode2fid(dchild->d_inode);

        op_data->op_fid2 = op_data->op_fid3;
        rc = md_unlink(ll_i2sbi(dir)->ll_md_exp, op_data, &request);
        ll_finish_md_op_data(op_data);
        if (rc)
                goto out;

        ll_update_times(request, dir);
        ll_stats_ops_tally(ll_i2sbi(dir), LPROC_LL_UNLINK, 1);

 out:
        ptlrpc_req_finished(request);
        return rc;
}

static int ll_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
        int err;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir" DFID "(%p)\n",
               dentry, PFID(ll_inode2fid(dir)), dir);

        if (!IS_POSIXACL(dir) || !exp_connect_umask(ll_i2mdexp(dir)))
                mode &= ~current_umask();
        mode = (mode & (0777 | S_ISVTX)) | S_IFDIR;

        err = ll_new_node(dir, dentry, NULL, mode, 0, LUSTRE_OPC_MKDIR);
        if (!err)
                ll_stats_ops_tally(ll_i2sbi(dir), LPROC_LL_MKDIR, 1);

        return err;
}

static int ll_rmdir(struct inode *dir, struct dentry *dchild)
{
        struct ptlrpc_request *request = NULL;
        struct md_op_data *op_data;
        int rc;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p)\n",
               dchild, PFID(ll_inode2fid(dir)), dir);

        op_data = ll_prep_md_op_data(NULL, dir, NULL,
                                     dchild->d_name.name,
                                     dchild->d_name.len,
                                     S_IFDIR, LUSTRE_OPC_ANY, NULL);
        if (IS_ERR(op_data))
                return PTR_ERR(op_data);

        if (dchild->d_inode)
                op_data->op_fid3 = *ll_inode2fid(dchild->d_inode);

        op_data->op_fid2 = op_data->op_fid3;
        rc = md_unlink(ll_i2sbi(dir)->ll_md_exp, op_data, &request);
        ll_finish_md_op_data(op_data);
        if (rc == 0) {
                ll_update_times(request, dir);
                ll_stats_ops_tally(ll_i2sbi(dir), LPROC_LL_RMDIR, 1);
        }

        ptlrpc_req_finished(request);
        return rc;
}

static int ll_symlink(struct inode *dir, struct dentry *dentry,
                      const char *oldname)
{
        int err;

        CDEBUG(D_VFSTRACE, "VFS Op:name=%pd, dir=" DFID "(%p),target=%.*s\n",
               dentry, PFID(ll_inode2fid(dir)), dir, 3000, oldname);

        err = ll_new_node(dir, dentry, oldname, S_IFLNK | 0777,
                          0, LUSTRE_OPC_SYMLINK);

        if (!err)
                ll_stats_ops_tally(ll_i2sbi(dir), LPROC_LL_SYMLINK, 1);

        return err;
}

static int ll_link(struct dentry *old_dentry, struct inode *dir,
                   struct dentry *new_dentry)
{
        struct inode *src = d_inode(old_dentry);
        struct ll_sb_info *sbi = ll_i2sbi(dir);
        struct ptlrpc_request *request = NULL;
        struct md_op_data *op_data;
        int err;

        CDEBUG(D_VFSTRACE, "VFS Op: inode=" DFID "(%p), dir=" DFID "(%p), target=%pd\n",
               PFID(ll_inode2fid(src)), src, PFID(ll_inode2fid(dir)), dir,
               new_dentry);

        op_data = ll_prep_md_op_data(NULL, src, dir, new_dentry->d_name.name,
                                     new_dentry->d_name.len,
                                     0, LUSTRE_OPC_ANY, NULL);
        if (IS_ERR(op_data))
                return PTR_ERR(op_data);

        err = md_link(sbi->ll_md_exp, op_data, &request);
        ll_finish_md_op_data(op_data);
        if (err)
                goto out;

        ll_update_times(request, dir);
        ll_stats_ops_tally(sbi, LPROC_LL_LINK, 1);
out:
        ptlrpc_req_finished(request);
        return err;
}

static int ll_rename(struct inode *src, struct dentry *src_dchild,
                     struct inode *tgt, struct dentry *tgt_dchild,
                     unsigned int flags)
{
        struct ptlrpc_request *request = NULL;
        struct ll_sb_info *sbi = ll_i2sbi(src);
        struct md_op_data *op_data;
        int err;

        if (flags)
                return -EINVAL;

        CDEBUG(D_VFSTRACE,
               "VFS Op:oldname=%pd, src_dir=" DFID "(%p), newname=%pd, tgt_dir=" DFID "(%p)\n",
               src_dchild, PFID(ll_inode2fid(src)), src,
               tgt_dchild, PFID(ll_inode2fid(tgt)), tgt);

        op_data = ll_prep_md_op_data(NULL, src, tgt, NULL, 0, 0,
                                     LUSTRE_OPC_ANY, NULL);
        if (IS_ERR(op_data))
                return PTR_ERR(op_data);

        if (src_dchild->d_inode)
                op_data->op_fid3 = *ll_inode2fid(src_dchild->d_inode);
        if (tgt_dchild->d_inode)
                op_data->op_fid4 = *ll_inode2fid(tgt_dchild->d_inode);

        err = md_rename(sbi->ll_md_exp, op_data,
                        src_dchild->d_name.name,
                        src_dchild->d_name.len,
                        tgt_dchild->d_name.name,
                        tgt_dchild->d_name.len, &request);
        ll_finish_md_op_data(op_data);
        if (!err) {
                ll_update_times(request, src);
                ll_update_times(request, tgt);
                ll_stats_ops_tally(sbi, LPROC_LL_RENAME, 1);
        }

        ptlrpc_req_finished(request);
        if (!err)
                d_move(src_dchild, tgt_dchild);
        return err;
}

const struct inode_operations ll_dir_inode_operations = {
        .mknod        = ll_mknod,
        .atomic_open        = ll_atomic_open,
        .lookup      = ll_lookup_nd,
        .create      = ll_create_nd,
        /* We need all these non-raw things for NFSD, to not patch it. */
        .unlink      = ll_unlink,
        .mkdir        = ll_mkdir,
        .rmdir        = ll_rmdir,
        .symlink            = ll_symlink,
        .link          = ll_link,
        .rename         = ll_rename,
        .setattr            = ll_setattr,
        .getattr            = ll_getattr,
        .permission      = ll_inode_permission,
        .listxattr        = ll_listxattr,
        .get_acl            = ll_get_acl,
};

const struct inode_operations ll_special_inode_operations = {
        .setattr        = ll_setattr,
        .getattr        = ll_getattr,
        .permission     = ll_inode_permission,
        .listxattr      = ll_listxattr,
        .get_acl            = ll_get_acl,
};