// SPDX-License-Identifier: CDDL-1.0
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or https://opensource.org/licenses/CDDL-1.0.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2011, Lawrence Livermore National Security, LLC.
 * Copyright (c) 2015 by Chunwei Chen. All rights reserved.
 * Copyright (c) 2025, Rob Norris <robn@despairlabs.com>
 */


#include <sys/sysmacros.h>
#include <sys/zfs_ctldir.h>
#include <sys/zfs_vfsops.h>
#include <sys/zfs_vnops.h>
#include <sys/zfs_znode.h>
#include <sys/dmu_objset.h>
#include <sys/spa_impl.h>
#include <sys/vfs.h>
#include <sys/zpl.h>
#include <sys/file.h>

static struct dentry *
zpl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
	cred_t *cr = CRED();
	struct inode *ip;
	znode_t *zp;
	int error;
	fstrans_cookie_t cookie;
	pathname_t *ppn = NULL;
	pathname_t pn;
	int zfs_flags = 0;
	zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;
	dsl_dataset_t *ds = dmu_objset_ds(zfsvfs->z_os);
	size_t dlen = dlen(dentry);

	/*
	 * If z_longname is disabled, disallow create or rename of names
	 * longer than ZAP_MAXNAMELEN.
	 *
	 * This is needed in cases where longname was enabled first and some
	 * files/dirs with names > ZAP_MAXNAMELEN were created. And later
	 * longname was disabled. In such a case allow access to existing
	 * longnames. But disallow creation newer longnamed entities.
	 */
	if (!zfsvfs->z_longname && (dlen >= ZAP_MAXNAMELEN)) {
		/*
		 * If this is for create or rename fail it.
		 */
		if (!dsl_dataset_feature_is_active(ds, SPA_FEATURE_LONGNAME) ||
		    (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)))
			return (ERR_PTR(-ENAMETOOLONG));
	}
	if (dlen >= ZAP_MAXNAMELEN_NEW) {
		return (ERR_PTR(-ENAMETOOLONG));
	}

	crhold(cr);
	cookie = spl_fstrans_mark();

	/* If we are a case insensitive fs, we need the real name */
	if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
		zfs_flags = FIGNORECASE;
		pn_alloc(&pn);
		ppn = &pn;
	}

	error = -zfs_lookup(ITOZ(dir), dname(dentry), &zp,
	    zfs_flags, cr, NULL, ppn);
	spl_fstrans_unmark(cookie);
	ASSERT3S(error, <=, 0);
	crfree(cr);

	spin_lock(&dentry->d_lock);
	dentry->d_time = jiffies;
	spin_unlock(&dentry->d_lock);

	if (error) {
		/*
		 * If we have a case sensitive fs, we do not want to
		 * insert negative entries, so return NULL for ENOENT.
		 * Fall through if the error is not ENOENT. Also free memory.
		 */
		if (ppn) {
			pn_free(ppn);
			if (error == -ENOENT)
				return (NULL);
		}

		if (error == -ENOENT)
			return (d_splice_alias(NULL, dentry));
		else
			return (ERR_PTR(error));
	}
	ip = ZTOI(zp);

	/*
	 * If we are case insensitive, call the correct function
	 * to install the name.
	 */
	if (ppn) {
		struct dentry *new_dentry;
		struct qstr ci_name;

		if (strcmp(dname(dentry), pn.pn_buf) == 0) {
			new_dentry = d_splice_alias(ip,  dentry);
		} else {
			ci_name.name = pn.pn_buf;
			ci_name.len = strlen(pn.pn_buf);
			new_dentry = d_add_ci(dentry, ip, &ci_name);
		}
		pn_free(ppn);
		return (new_dentry);
	} else {
		return (d_splice_alias(ip, dentry));
	}
}

void
zpl_vap_init(vattr_t *vap, struct inode *dir, umode_t mode, cred_t *cr,
    zidmap_t *mnt_ns)
{
	vap->va_mask = ATTR_MODE;
	vap->va_mode = mode;

	vap->va_uid = zfs_vfsuid_to_uid(mnt_ns,
	    zfs_i_user_ns(dir), crgetuid(cr));

	if (dir->i_mode & S_ISGID) {
		vap->va_gid = KGID_TO_SGID(dir->i_gid);
		if (S_ISDIR(mode))
			vap->va_mode |= S_ISGID;
	} else {
		vap->va_gid = zfs_vfsgid_to_gid(mnt_ns,
		    zfs_i_user_ns(dir), crgetgid(cr));
	}
}

static inline bool
is_nametoolong(struct dentry *dentry)
{
	zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;
	size_t dlen = dlen(dentry);

	return ((!zfsvfs->z_longname && dlen >= ZAP_MAXNAMELEN) ||
	    dlen >= ZAP_MAXNAMELEN_NEW);
}

static int
#ifdef HAVE_IOPS_CREATE_USERNS
zpl_create(struct user_namespace *user_ns, struct inode *dir,
    struct dentry *dentry, umode_t mode, bool flag)
#elif defined(HAVE_IOPS_CREATE_IDMAP)
zpl_create(struct mnt_idmap *user_ns, struct inode *dir,
    struct dentry *dentry, umode_t mode, bool flag)
#else
zpl_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool flag)
#endif
{
	cred_t *cr = CRED();
	znode_t *zp;
	vattr_t *vap;
	int error;
	fstrans_cookie_t cookie;
#if !(defined(HAVE_IOPS_CREATE_USERNS) || defined(HAVE_IOPS_CREATE_IDMAP))
	zidmap_t *user_ns = kcred->user_ns;
#endif

	if (is_nametoolong(dentry)) {
		return (-ENAMETOOLONG);
	}

	crhold(cr);
	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
	zpl_vap_init(vap, dir, mode, cr, user_ns);

	cookie = spl_fstrans_mark();
	error = -zfs_create(ITOZ(dir), dname(dentry), vap, 0,
	    mode, &zp, cr, 0, NULL, user_ns);
	if (error == 0) {
		error = zpl_xattr_security_init(ZTOI(zp), dir, &dentry->d_name);
		if (error == 0)
			error = zpl_init_acl(ZTOI(zp), dir);

		if (error) {
			(void) zfs_remove(ITOZ(dir), dname(dentry), cr, 0);
			remove_inode_hash(ZTOI(zp));
			iput(ZTOI(zp));
		} else {
			d_instantiate(dentry, ZTOI(zp));
		}
	}

	spl_fstrans_unmark(cookie);
	kmem_free(vap, sizeof (vattr_t));
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
#ifdef HAVE_IOPS_MKNOD_USERNS
zpl_mknod(struct user_namespace *user_ns, struct inode *dir,
    struct dentry *dentry, umode_t mode,
#elif defined(HAVE_IOPS_MKNOD_IDMAP)
zpl_mknod(struct mnt_idmap *user_ns, struct inode *dir,
    struct dentry *dentry, umode_t mode,
#else
zpl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
#endif
    dev_t rdev)
{
	cred_t *cr = CRED();
	znode_t *zp;
	vattr_t *vap;
	int error;
	fstrans_cookie_t cookie;
#if !(defined(HAVE_IOPS_MKNOD_USERNS) || defined(HAVE_IOPS_MKNOD_IDMAP))
	zidmap_t *user_ns = kcred->user_ns;
#endif

	if (is_nametoolong(dentry)) {
		return (-ENAMETOOLONG);
	}

	/*
	 * We currently expect Linux to supply rdev=0 for all sockets
	 * and fifos, but we want to know if this behavior ever changes.
	 */
	if (S_ISSOCK(mode) || S_ISFIFO(mode))
		ASSERT(rdev == 0);

	crhold(cr);
	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
	zpl_vap_init(vap, dir, mode, cr, user_ns);
	vap->va_rdev = rdev;

	cookie = spl_fstrans_mark();
	error = -zfs_create(ITOZ(dir), dname(dentry), vap, 0,
	    mode, &zp, cr, 0, NULL, user_ns);
	if (error == 0) {
		error = zpl_xattr_security_init(ZTOI(zp), dir, &dentry->d_name);
		if (error == 0)
			error = zpl_init_acl(ZTOI(zp), dir);

		if (error) {
			(void) zfs_remove(ITOZ(dir), dname(dentry), cr, 0);
			remove_inode_hash(ZTOI(zp));
			iput(ZTOI(zp));
		} else {
			d_instantiate(dentry, ZTOI(zp));
		}
	}

	spl_fstrans_unmark(cookie);
	kmem_free(vap, sizeof (vattr_t));
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
#ifdef HAVE_TMPFILE_IDMAP
zpl_tmpfile(struct mnt_idmap *userns, struct inode *dir,
    struct file *file, umode_t mode)
#elif !defined(HAVE_TMPFILE_DENTRY)
zpl_tmpfile(struct user_namespace *userns, struct inode *dir,
    struct file *file, umode_t mode)
#else
#ifdef HAVE_TMPFILE_USERNS
zpl_tmpfile(struct user_namespace *userns, struct inode *dir,
    struct dentry *dentry, umode_t mode)
#else
zpl_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
#endif
#endif
{
	cred_t *cr = CRED();
	struct inode *ip;
	vattr_t *vap;
	int error;
	fstrans_cookie_t cookie;
#if !(defined(HAVE_TMPFILE_USERNS) || defined(HAVE_TMPFILE_IDMAP))
	zidmap_t *userns = kcred->user_ns;
#endif

	crhold(cr);
	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
	/*
	 * The VFS does not apply the umask, therefore it is applied here
	 * when POSIX ACLs are not enabled.
	 */
	if (!IS_POSIXACL(dir))
		mode &= ~current_umask();
	zpl_vap_init(vap, dir, mode, cr, userns);

	cookie = spl_fstrans_mark();
	error = -zfs_tmpfile(dir, vap, 0, mode, &ip, cr, 0, NULL, userns);
	if (error == 0) {
		/* d_tmpfile will do drop_nlink, so we should set it first */
		set_nlink(ip, 1);
#ifndef HAVE_TMPFILE_DENTRY
		d_tmpfile(file, ip);

		error = zpl_xattr_security_init(ip, dir,
		    &file->f_path.dentry->d_name);
#else
		d_tmpfile(dentry, ip);

		error = zpl_xattr_security_init(ip, dir, &dentry->d_name);
#endif
		if (error == 0)
			error = zpl_init_acl(ip, dir);
#ifndef HAVE_TMPFILE_DENTRY
		error = finish_open_simple(file, error);
#endif
		/*
		 * don't need to handle error here, file is already in
		 * unlinked set.
		 */
	}

	spl_fstrans_unmark(cookie);
	kmem_free(vap, sizeof (vattr_t));
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
zpl_unlink(struct inode *dir, struct dentry *dentry)
{
	cred_t *cr = CRED();
	int error;
	fstrans_cookie_t cookie;
	zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;

	crhold(cr);
	cookie = spl_fstrans_mark();
	error = -zfs_remove(ITOZ(dir), dname(dentry), cr, 0);

	/*
	 * For a CI FS we must invalidate the dentry to prevent the
	 * creation of negative entries.
	 */
	if (error == 0 && zfsvfs->z_case == ZFS_CASE_INSENSITIVE)
		d_invalidate(dentry);

	spl_fstrans_unmark(cookie);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

#if defined(HAVE_IOPS_MKDIR_USERNS)
static int
zpl_mkdir(struct user_namespace *user_ns, struct inode *dir,
    struct dentry *dentry, umode_t mode)
#elif defined(HAVE_IOPS_MKDIR_IDMAP)
static int
zpl_mkdir(struct mnt_idmap *user_ns, struct inode *dir,
    struct dentry *dentry, umode_t mode)
#elif defined(HAVE_IOPS_MKDIR_DENTRY)
static struct dentry *
zpl_mkdir(struct mnt_idmap *user_ns, struct inode *dir,
    struct dentry *dentry, umode_t mode)
#else
static int
zpl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
#endif
{
	cred_t *cr = CRED();
	vattr_t *vap;
	znode_t *zp;
	int error;
	fstrans_cookie_t cookie;
#if !(defined(HAVE_IOPS_MKDIR_USERNS) || \
	defined(HAVE_IOPS_MKDIR_IDMAP) || defined(HAVE_IOPS_MKDIR_DENTRY))
	zidmap_t *user_ns = kcred->user_ns;
#endif

	if (is_nametoolong(dentry)) {
		error = -ENAMETOOLONG;
		goto err;
	}

	crhold(cr);
	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
	zpl_vap_init(vap, dir, mode | S_IFDIR, cr, user_ns);

	cookie = spl_fstrans_mark();
	error = -zfs_mkdir(ITOZ(dir), dname(dentry), vap, &zp, cr, 0, NULL,
	    user_ns);
	if (error == 0) {
		error = zpl_xattr_security_init(ZTOI(zp), dir, &dentry->d_name);
		if (error == 0)
			error = zpl_init_acl(ZTOI(zp), dir);

		if (error) {
			(void) zfs_rmdir(ITOZ(dir), dname(dentry), NULL, cr, 0);
			remove_inode_hash(ZTOI(zp));
			iput(ZTOI(zp));
		} else {
			d_instantiate(dentry, ZTOI(zp));
		}
	}

	spl_fstrans_unmark(cookie);
	kmem_free(vap, sizeof (vattr_t));
	crfree(cr);

err:
	ASSERT3S(error, <=, 0);
#if defined(HAVE_IOPS_MKDIR_DENTRY)
	return (error != 0 ? ERR_PTR(error) : NULL);
#else
	return (error);
#endif
}

static int
zpl_rmdir(struct inode *dir, struct dentry *dentry)
{
	cred_t *cr = CRED();
	int error;
	fstrans_cookie_t cookie;
	zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;

	crhold(cr);
	cookie = spl_fstrans_mark();
	error = -zfs_rmdir(ITOZ(dir), dname(dentry), NULL, cr, 0);

	/*
	 * For a CI FS we must invalidate the dentry to prevent the
	 * creation of negative entries.
	 */
	if (error == 0 && zfsvfs->z_case == ZFS_CASE_INSENSITIVE)
		d_invalidate(dentry);

	spl_fstrans_unmark(cookie);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
#ifdef HAVE_USERNS_IOPS_GETATTR
zpl_getattr_impl(struct user_namespace *user_ns,
    const struct path *path, struct kstat *stat, u32 request_mask,
    unsigned int query_flags)
#elif defined(HAVE_IDMAP_IOPS_GETATTR)
zpl_getattr_impl(struct mnt_idmap *user_ns,
    const struct path *path, struct kstat *stat, u32 request_mask,
    unsigned int query_flags)
#else
zpl_getattr_impl(const struct path *path, struct kstat *stat, u32 request_mask,
    unsigned int query_flags)
#endif
{
	int error;
	fstrans_cookie_t cookie;
	struct inode *ip = path->dentry->d_inode;
	znode_t *zp __maybe_unused = ITOZ(ip);

	cookie = spl_fstrans_mark();

	/*
	 * XXX query_flags currently ignored.
	 */

#ifdef HAVE_GENERIC_FILLATTR_IDMAP_REQMASK
	error = -zfs_getattr_fast(user_ns, request_mask, ip, stat);
#elif (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
	error = -zfs_getattr_fast(user_ns, ip, stat);
#else
	error = -zfs_getattr_fast(kcred->user_ns, ip, stat);
#endif

#ifdef STATX_BTIME
	if (request_mask & STATX_BTIME) {
		stat->btime = zp->z_btime;
		stat->result_mask |= STATX_BTIME;
	}
#endif

#ifdef STATX_DIOALIGN
	if (request_mask & STATX_DIOALIGN) {
		uint64_t align;
		if (zfs_get_direct_alignment(zp, &align) == 0) {
			stat->dio_mem_align = PAGE_SIZE;
			stat->dio_offset_align = align;
			stat->result_mask |= STATX_DIOALIGN;
		}
	}
#endif

#ifdef STATX_ATTR_IMMUTABLE
	if (zp->z_pflags & ZFS_IMMUTABLE)
		stat->attributes |= STATX_ATTR_IMMUTABLE;
	stat->attributes_mask |= STATX_ATTR_IMMUTABLE;
#endif

#ifdef STATX_ATTR_APPEND
	if (zp->z_pflags & ZFS_APPENDONLY)
		stat->attributes |= STATX_ATTR_APPEND;
	stat->attributes_mask |= STATX_ATTR_APPEND;
#endif

#ifdef STATX_ATTR_NODUMP
	if (zp->z_pflags & ZFS_NODUMP)
		stat->attributes |= STATX_ATTR_NODUMP;
	stat->attributes_mask |= STATX_ATTR_NODUMP;
#endif

	spl_fstrans_unmark(cookie);
	ASSERT3S(error, <=, 0);

	return (error);
}
ZPL_GETATTR_WRAPPER(zpl_getattr);

static int
#ifdef HAVE_USERNS_IOPS_SETATTR
zpl_setattr(struct user_namespace *user_ns, struct dentry *dentry,
    struct iattr *ia)
#elif defined(HAVE_IDMAP_IOPS_SETATTR)
zpl_setattr(struct mnt_idmap *user_ns, struct dentry *dentry,
    struct iattr *ia)
#else
zpl_setattr(struct dentry *dentry, struct iattr *ia)
#endif
{
	struct inode *ip = dentry->d_inode;
	cred_t *cr = CRED();
	vattr_t *vap;
	int error;
	fstrans_cookie_t cookie;

#ifdef HAVE_SETATTR_PREPARE_USERNS
	error = zpl_setattr_prepare(user_ns, dentry, ia);
#elif defined(HAVE_SETATTR_PREPARE_IDMAP)
	error = zpl_setattr_prepare(user_ns, dentry, ia);
#else
	error = zpl_setattr_prepare(zfs_init_idmap, dentry, ia);
#endif
	if (error)
		return (error);

	crhold(cr);
	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
	vap->va_mask = ia->ia_valid & ATTR_IATTR_MASK;
	vap->va_mode = ia->ia_mode;
	if (ia->ia_valid & ATTR_UID)
#ifdef HAVE_IATTR_VFSID
		vap->va_uid = zfs_vfsuid_to_uid(user_ns, zfs_i_user_ns(ip),
		    __vfsuid_val(ia->ia_vfsuid));
#else
		vap->va_uid = KUID_TO_SUID(ia->ia_uid);
#endif
	if (ia->ia_valid & ATTR_GID)
#ifdef HAVE_IATTR_VFSID
		vap->va_gid = zfs_vfsgid_to_gid(user_ns, zfs_i_user_ns(ip),
		    __vfsgid_val(ia->ia_vfsgid));
#else
		vap->va_gid = KGID_TO_SGID(ia->ia_gid);
#endif
	vap->va_size = ia->ia_size;
	vap->va_atime = ia->ia_atime;
	vap->va_mtime = ia->ia_mtime;
	vap->va_ctime = ia->ia_ctime;

	if (vap->va_mask & ATTR_ATIME)
		zpl_inode_set_atime_to_ts(ip,
		    zpl_inode_timestamp_truncate(ia->ia_atime, ip));

	cookie = spl_fstrans_mark();
#ifdef HAVE_USERNS_IOPS_SETATTR
	error = -zfs_setattr(ITOZ(ip), vap, 0, cr, user_ns);
#elif defined(HAVE_IDMAP_IOPS_SETATTR)
	error = -zfs_setattr(ITOZ(ip), vap, 0, cr, user_ns);
#else
	error = -zfs_setattr(ITOZ(ip), vap, 0, cr, zfs_init_idmap);
#endif
	if (!error && (ia->ia_valid & ATTR_MODE))
		error = zpl_chmod_acl(ip);

	spl_fstrans_unmark(cookie);
	kmem_free(vap, sizeof (vattr_t));
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
#ifdef HAVE_IOPS_RENAME_USERNS
zpl_rename2(struct user_namespace *user_ns, struct inode *sdip,
    struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
    unsigned int rflags)
#elif defined(HAVE_IOPS_RENAME_IDMAP)
zpl_rename2(struct mnt_idmap *user_ns, struct inode *sdip,
    struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
    unsigned int rflags)
#else
zpl_rename2(struct inode *sdip, struct dentry *sdentry,
    struct inode *tdip, struct dentry *tdentry, unsigned int rflags)
#endif
{
	cred_t *cr = CRED();
	vattr_t *wo_vap = NULL;
	int error;
	fstrans_cookie_t cookie;
#if !(defined(HAVE_IOPS_RENAME_USERNS) || defined(HAVE_IOPS_RENAME_IDMAP))
	zidmap_t *user_ns = kcred->user_ns;
#endif

	if (is_nametoolong(tdentry)) {
		return (-ENAMETOOLONG);
	}

	crhold(cr);
	if (rflags & RENAME_WHITEOUT) {
		wo_vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
		zpl_vap_init(wo_vap, sdip, S_IFCHR, cr, user_ns);
		wo_vap->va_rdev = makedevice(0, 0);
	}

	cookie = spl_fstrans_mark();
	error = -zfs_rename(ITOZ(sdip), dname(sdentry), ITOZ(tdip),
	    dname(tdentry), cr, 0, rflags, wo_vap, user_ns);
	spl_fstrans_unmark(cookie);
	if (wo_vap)
		kmem_free(wo_vap, sizeof (vattr_t));
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

#if !defined(HAVE_IOPS_RENAME_USERNS) && \
	!defined(HAVE_RENAME_WANTS_FLAGS) && \
	!defined(HAVE_IOPS_RENAME_IDMAP)
static int
zpl_rename(struct inode *sdip, struct dentry *sdentry,
    struct inode *tdip, struct dentry *tdentry)
{
	return (zpl_rename2(sdip, sdentry, tdip, tdentry, 0));
}
#endif

static int
#ifdef HAVE_IOPS_SYMLINK_USERNS
zpl_symlink(struct user_namespace *user_ns, struct inode *dir,
    struct dentry *dentry, const char *name)
#elif defined(HAVE_IOPS_SYMLINK_IDMAP)
zpl_symlink(struct mnt_idmap *user_ns, struct inode *dir,
    struct dentry *dentry, const char *name)
#else
zpl_symlink(struct inode *dir, struct dentry *dentry, const char *name)
#endif
{
	cred_t *cr = CRED();
	vattr_t *vap;
	znode_t *zp;
	int error;
	fstrans_cookie_t cookie;
#if !(defined(HAVE_IOPS_SYMLINK_USERNS) || defined(HAVE_IOPS_SYMLINK_IDMAP))
	zidmap_t *user_ns = kcred->user_ns;
#endif

	if (is_nametoolong(dentry)) {
		return (-ENAMETOOLONG);
	}

	crhold(cr);
	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
	zpl_vap_init(vap, dir, S_IFLNK | S_IRWXUGO, cr, user_ns);

	cookie = spl_fstrans_mark();
	error = -zfs_symlink(ITOZ(dir), dname(dentry), vap,
	    (char *)name, &zp, cr, 0, user_ns);
	if (error == 0) {
		error = zpl_xattr_security_init(ZTOI(zp), dir, &dentry->d_name);
		if (error) {
			(void) zfs_remove(ITOZ(dir), dname(dentry), cr, 0);
			remove_inode_hash(ZTOI(zp));
			iput(ZTOI(zp));
		} else {
			d_instantiate(dentry, ZTOI(zp));
		}
	}

	spl_fstrans_unmark(cookie);
	kmem_free(vap, sizeof (vattr_t));
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static void
zpl_put_link(void *ptr)
{
	kmem_free(ptr, MAXPATHLEN);
}

static int
zpl_get_link_common(struct dentry *dentry, struct inode *ip, char **link)
{
	fstrans_cookie_t cookie;
	cred_t *cr = CRED();
	int error;

	crhold(cr);
	*link = NULL;

	struct iovec iov;
	iov.iov_len = MAXPATHLEN;
	iov.iov_base = kmem_zalloc(MAXPATHLEN, KM_SLEEP);

	zfs_uio_t uio;
	zfs_uio_iovec_init(&uio, &iov, 1, 0, UIO_SYSSPACE, MAXPATHLEN - 1, 0);

	cookie = spl_fstrans_mark();
	error = -zfs_readlink(ip, &uio, cr);
	spl_fstrans_unmark(cookie);
	crfree(cr);

	if (error)
		kmem_free(iov.iov_base, MAXPATHLEN);
	else
		*link = iov.iov_base;

	return (error);
}

static const char *
zpl_get_link(struct dentry *dentry, struct inode *inode,
    struct delayed_call *done)
{
	char *link = NULL;
	int error;

	if (!dentry)
		return (ERR_PTR(-ECHILD));

	error = zpl_get_link_common(dentry, inode, &link);
	if (error)
		return (ERR_PTR(error));

	set_delayed_call(done, zpl_put_link, link);

	return (link);
}

static int
zpl_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
	cred_t *cr = CRED();
	struct inode *ip = old_dentry->d_inode;
	int error;
	fstrans_cookie_t cookie;

	if (is_nametoolong(dentry)) {
		return (-ENAMETOOLONG);
	}

	if (ip->i_nlink >= ZFS_LINK_MAX)
		return (-EMLINK);

	crhold(cr);
	zpl_inode_set_ctime_to_ts(ip, current_time(ip));
	/* Must have an existing ref, so igrab() cannot return NULL */
	VERIFY3P(igrab(ip), !=, NULL);

	cookie = spl_fstrans_mark();
	error = -zfs_link(ITOZ(dir), ITOZ(ip), dname(dentry), cr, 0);
	if (error) {
		iput(ip);
		goto out;
	}

	d_instantiate(dentry, ip);
out:
	spl_fstrans_unmark(cookie);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

const struct inode_operations zpl_inode_operations = {
	.setattr	= zpl_setattr,
	.getattr	= zpl_getattr,
	.listxattr	= zpl_xattr_list,
#if defined(CONFIG_FS_POSIX_ACL)
	.set_acl	= zpl_set_acl,
#if defined(HAVE_GET_INODE_ACL)
	.get_inode_acl	= zpl_get_acl,
#else
	.get_acl	= zpl_get_acl,
#endif /* HAVE_GET_INODE_ACL */
#endif /* CONFIG_FS_POSIX_ACL */
};

const struct inode_operations zpl_dir_inode_operations = {
	.create		= zpl_create,
	.lookup		= zpl_lookup,
	.link		= zpl_link,
	.unlink		= zpl_unlink,
	.symlink	= zpl_symlink,
	.mkdir		= zpl_mkdir,
	.rmdir		= zpl_rmdir,
	.mknod		= zpl_mknod,
#if defined(HAVE_RENAME_WANTS_FLAGS) || defined(HAVE_IOPS_RENAME_USERNS)
	.rename		= zpl_rename2,
#elif defined(HAVE_IOPS_RENAME_IDMAP)
	.rename		= zpl_rename2,
#else
	.rename		= zpl_rename,
#endif
	.tmpfile	= zpl_tmpfile,
	.setattr	= zpl_setattr,
	.getattr	= zpl_getattr,
	.listxattr	= zpl_xattr_list,
#if defined(CONFIG_FS_POSIX_ACL)
	.set_acl	= zpl_set_acl,
#if defined(HAVE_GET_INODE_ACL)
	.get_inode_acl	= zpl_get_acl,
#else
	.get_acl	= zpl_get_acl,
#endif /* HAVE_GET_INODE_ACL */
#endif /* CONFIG_FS_POSIX_ACL */
};

const struct inode_operations zpl_symlink_inode_operations = {
	.get_link	= zpl_get_link,
	.setattr	= zpl_setattr,
	.getattr	= zpl_getattr,
	.listxattr	= zpl_xattr_list,
};

const struct inode_operations zpl_special_inode_operations = {
	.setattr	= zpl_setattr,
	.getattr	= zpl_getattr,
	.listxattr	= zpl_xattr_list,
#if defined(CONFIG_FS_POSIX_ACL)
	.set_acl	= zpl_set_acl,
#if defined(HAVE_GET_INODE_ACL)
	.get_inode_acl	= zpl_get_acl,
#else
	.get_acl	= zpl_get_acl,
#endif /* HAVE_GET_INODE_ACL */
#endif /* CONFIG_FS_POSIX_ACL */
};