text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * This file contains vfs inode ops for the 9P2000.L protocol.
   *
   *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   */
  
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <linux/fs.h>
  #include <linux/file.h>
  #include <linux/pagemap.h>
  #include <linux/stat.h>
  #include <linux/string.h>
  #include <linux/inet.h>
  #include <linux/namei.h>
  #include <linux/idr.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/xattr.h>
  #include <linux/posix_acl.h>
  #include <net/9p/9p.h>
  #include <net/9p/client.h>
  
  #include "v9fs.h"
  #include "v9fs_vfs.h"
  #include "fid.h"
  #include "cache.h"
  #include "xattr.h"
  #include "acl.h"
  
  static int
  v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
  		    struct dentry *dentry, umode_t omode, dev_t rdev);
  
  /**
   * v9fs_get_fsgid_for_create - Helper function to get the gid for a new object
   * @dir_inode: The directory inode
   *
   * Helper function to get the gid for creating a
   * new file system object. This checks the S_ISGID to determine the owning
   * group of the new file system object.
   */
  
  static kgid_t v9fs_get_fsgid_for_create(struct inode *dir_inode)
  {
  	BUG_ON(dir_inode == NULL);
  
  	if (dir_inode->i_mode & S_ISGID) {
  		/* set_gid bit is set.*/
  		return dir_inode->i_gid;
  	}
  	return current_fsgid();
  }
  
  static int v9fs_test_inode_dotl(struct inode *inode, void *data)
  {
  	struct v9fs_inode *v9inode = V9FS_I(inode);
  	struct p9_stat_dotl *st = (struct p9_stat_dotl *)data;
  
  	/* don't match inode of different type */
  	if (inode_wrong_type(inode, st->st_mode))
  		return 0;
  
  	if (inode->i_generation != st->st_gen)
  		return 0;
  
  	/* compare qid details */
  	if (memcmp(&v9inode->qid.version,
  		   &st->qid.version, sizeof(v9inode->qid.version)))
  		return 0;
  
  	if (v9inode->qid.type != st->qid.type)
  		return 0;
  
  	if (v9inode->qid.path != st->qid.path)
  		return 0;
  	return 1;
  }
  
  /* Always get a new inode */
  static int v9fs_test_new_inode_dotl(struct inode *inode, void *data)
  {
  	return 0;
  }
  
  static int v9fs_set_inode_dotl(struct inode *inode,  void *data)
  {
  	struct v9fs_inode *v9inode = V9FS_I(inode);
  	struct p9_stat_dotl *st = (struct p9_stat_dotl *)data;
  
  	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
  	inode->i_generation = st->st_gen;
  	return 0;
  }
  
  static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
  					struct p9_qid *qid,
  					struct p9_fid *fid,
  					struct p9_stat_dotl *st,
  					int new)
  {
  	int retval;
  	unsigned long i_ino;
  	struct inode *inode;
  	struct v9fs_session_info *v9ses = sb->s_fs_info;
  	int (*test)(struct inode *inode, void *data);
  
  	if (new)
  		test = v9fs_test_new_inode_dotl;
  	else
  		test = v9fs_test_inode_dotl;
  
  	i_ino = v9fs_qid2ino(qid);
  	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode_dotl, st);
  	if (!inode)
  		return ERR_PTR(-ENOMEM);
  	if (!(inode->i_state & I_NEW))
  		return inode;
  	/*
  	 * initialize the inode with the stat info
  	 * FIXME!! we may need support for stale inodes
  	 * later.
  	 */
  	inode->i_ino = i_ino;
  	retval = v9fs_init_inode(v9ses, inode,
  				 st->st_mode, new_decode_dev(st->st_rdev));
  	if (retval)
  		goto error;
  
  	v9fs_stat2inode_dotl(st, inode, 0);
  	v9fs_cache_inode_get_cookie(inode);
  	retval = v9fs_get_acl(inode, fid);
  	if (retval)
  		goto error;
  
  	unlock_new_inode(inode);
  	return inode;
  error:
  	iget_failed(inode);
  	return ERR_PTR(retval);
  
  }
  
  struct inode *
  v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses, struct p9_fid *fid,
  			 struct super_block *sb, int new)
  {
  	struct p9_stat_dotl *st;
  	struct inode *inode = NULL;
  
  	st = p9_client_getattr_dotl(fid, P9_STATS_BASIC | P9_STATS_GEN);
  	if (IS_ERR(st))
  		return ERR_CAST(st);
  
  	inode = v9fs_qid_iget_dotl(sb, &st->qid, fid, st, new);
  	kfree(st);
  	return inode;
  }
  
  struct dotl_openflag_map {
  	int open_flag;
  	int dotl_flag;
  };
  
  static int v9fs_mapped_dotl_flags(int flags)
  {
  	int i;
  	int rflags = 0;
  	struct dotl_openflag_map dotl_oflag_map[] = {
  		{ O_CREAT,	P9_DOTL_CREATE },
  		{ O_EXCL,	P9_DOTL_EXCL },
  		{ O_NOCTTY,	P9_DOTL_NOCTTY },
  		{ O_APPEND,	P9_DOTL_APPEND },
  		{ O_NONBLOCK,	P9_DOTL_NONBLOCK },
  		{ O_DSYNC,	P9_DOTL_DSYNC },
  		{ FASYNC,	P9_DOTL_FASYNC },
  		{ O_DIRECT,	P9_DOTL_DIRECT },
  		{ O_LARGEFILE,	P9_DOTL_LARGEFILE },
  		{ O_DIRECTORY,	P9_DOTL_DIRECTORY },
  		{ O_NOFOLLOW,	P9_DOTL_NOFOLLOW },
  		{ O_NOATIME,	P9_DOTL_NOATIME },
  		{ O_CLOEXEC,	P9_DOTL_CLOEXEC },
  		{ O_SYNC,	P9_DOTL_SYNC},
  	};
  	for (i = 0; i < ARRAY_SIZE(dotl_oflag_map); i++) {
  		if (flags & dotl_oflag_map[i].open_flag)
  			rflags |= dotl_oflag_map[i].dotl_flag;
  	}
  	return rflags;
  }
  
  /**
   * v9fs_open_to_dotl_flags- convert Linux specific open flags to
   * plan 9 open flag.
   * @flags: flags to convert
   */
  int v9fs_open_to_dotl_flags(int flags)
  {
  	int rflags = 0;
  
  	/*
  	 * We have same bits for P9_DOTL_READONLY, P9_DOTL_WRONLY
  	 * and P9_DOTL_NOACCESS
  	 */
  	rflags |= flags & O_ACCMODE;
  	rflags |= v9fs_mapped_dotl_flags(flags);
  
  	return rflags;
  }
  
  /**
   * v9fs_vfs_create_dotl - VFS hook to create files for 9P2000.L protocol.
   * @mnt_userns: The user namespace of the mount
   * @dir: directory inode that is being created
   * @dentry:  dentry that is being deleted
   * @omode: create permissions
   * @excl: True if the file must not yet exist
   *
   */
  static int
  v9fs_vfs_create_dotl(struct user_namespace *mnt_userns, struct inode *dir,
  		     struct dentry *dentry, umode_t omode, bool excl)
  {
  	return v9fs_vfs_mknod_dotl(mnt_userns, dir, dentry, omode, 0);
  }
  
  static int
  v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
  			  struct file *file, unsigned int flags, umode_t omode)
  {
  	int err = 0;
  	kgid_t gid;
  	umode_t mode;
  	const unsigned char *name = NULL;
  	struct p9_qid qid;
  	struct inode *inode;
  	struct p9_fid *fid = NULL;
  	struct v9fs_inode *v9inode;
  	struct p9_fid *dfid, *ofid, *inode_fid;
  	struct v9fs_session_info *v9ses;
  	struct posix_acl *pacl = NULL, *dacl = NULL;
  	struct dentry *res = NULL;
  
  	if (d_in_lookup(dentry)) {
  		res = v9fs_vfs_lookup(dir, dentry, 0);
  		if (IS_ERR(res))
  			return PTR_ERR(res);
  
  		if (res)
  			dentry = res;
  	}
  
  	/* Only creates */
  	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
  		return	finish_no_open(file, res);
  
  	v9ses = v9fs_inode2v9ses(dir);
  
  	name = dentry->d_name.name;
  	p9_debug(P9_DEBUG_VFS, "name:%s flags:0x%x mode:0x%x\n",
  		 name, flags, omode);
  
  	dfid = v9fs_parent_fid(dentry);
  	if (IS_ERR(dfid)) {
  		err = PTR_ERR(dfid);
  		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
  		goto out;
  	}
  
  	/* clone a fid to use for creation */
  	ofid = clone_fid(dfid);
  	if (IS_ERR(ofid)) {
  		err = PTR_ERR(ofid);
  		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
  		goto out;
  	}
  
  	gid = v9fs_get_fsgid_for_create(dir);
  
  	mode = omode;
  	/* Update mode based on ACL value */
  	err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
  	if (err) {
  		p9_debug(P9_DEBUG_VFS, "Failed to get acl values in creat %d\n",
  			 err);
  		goto error;
  	}
  	err = p9_client_create_dotl(ofid, name, v9fs_open_to_dotl_flags(flags),
  				    mode, gid, &qid);
  	if (err < 0) {
  		p9_debug(P9_DEBUG_VFS, "p9_client_open_dotl failed in creat %d\n",
  			 err);
  		goto error;
  	}
  	v9fs_invalidate_inode_attr(dir);
  
  	/* instantiate inode and assign the unopened fid to the dentry */
  	fid = p9_client_walk(dfid, 1, &name, 1);
  	p9_client_clunk(dfid);
  	if (IS_ERR(fid)) {
  		err = PTR_ERR(fid);
  		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
  		fid = NULL;
  		goto error;
  	}
  	inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
  	if (IS_ERR(inode)) {
  		err = PTR_ERR(inode);
  		p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n", err);
  		goto error;
  	}
  	/* Now set the ACL based on the default value */
  	v9fs_set_create_acl(inode, fid, dacl, pacl);
  
  	v9fs_fid_add(dentry, fid);
  	d_instantiate(dentry, inode);
  
  	v9inode = V9FS_I(inode);
  	mutex_lock(&v9inode->v_mutex);
  	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
  	    !v9inode->writeback_fid &&
  	    ((flags & O_ACCMODE) != O_RDONLY)) {
  		/*
  		 * clone a fid and add it to writeback_fid
  		 * we do it during open time instead of
  		 * page dirty time via write_begin/page_mkwrite
  		 * because we want write after unlink usecase
  		 * to work.
  		 */
  		inode_fid = v9fs_writeback_fid(dentry);
  		if (IS_ERR(inode_fid)) {
  			err = PTR_ERR(inode_fid);
  			mutex_unlock(&v9inode->v_mutex);
  			goto err_clunk_old_fid;
  		}
  		v9inode->writeback_fid = (void *) inode_fid;
  	}
  	mutex_unlock(&v9inode->v_mutex);
  	/* Since we are opening a file, assign the open fid to the file */
  	err = finish_open(file, dentry, generic_file_open);
  	if (err)
  		goto err_clunk_old_fid;
  	file->private_data = ofid;
  	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
  		fscache_use_cookie(v9fs_inode_cookie(v9inode),
  				   file->f_mode & FMODE_WRITE);
  	v9fs_open_fid_add(inode, ofid);
  	file->f_mode |= FMODE_CREATED;
  out:
  	v9fs_put_acl(dacl, pacl);
  	dput(res);
  	return err;
  
  error:
  	if (fid)
  		p9_client_clunk(fid);
  err_clunk_old_fid:
  	if (ofid)
  		p9_client_clunk(ofid);
  	goto out;
  }
  
  /**
   * v9fs_vfs_mkdir_dotl - VFS mkdir hook to create a directory
   * @mnt_userns: The user namespace of the mount
   * @dir:  inode that is being unlinked
   * @dentry: dentry that is being unlinked
   * @omode: mode for new directory
   *
   */
  
  static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
  			       struct inode *dir, struct dentry *dentry,
  			       umode_t omode)
  {
  	int err;
  	struct v9fs_session_info *v9ses;
  	struct p9_fid *fid = NULL, *dfid = NULL;
  	kgid_t gid;
  	const unsigned char *name;
  	umode_t mode;
  	struct inode *inode;
  	struct p9_qid qid;
  	struct posix_acl *dacl = NULL, *pacl = NULL;
  
  	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
  	err = 0;
  	v9ses = v9fs_inode2v9ses(dir);
  
  	omode |= S_IFDIR;
  	if (dir->i_mode & S_ISGID)
  		omode |= S_ISGID;
  
  	dfid = v9fs_parent_fid(dentry);
  	if (IS_ERR(dfid)) {
  		err = PTR_ERR(dfid);
  		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
  		dfid = NULL;
  		goto error;
  	}
  
  	gid = v9fs_get_fsgid_for_create(dir);
  	mode = omode;
  	/* Update mode based on ACL value */
  	err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
  	if (err) {
  		p9_debug(P9_DEBUG_VFS, "Failed to get acl values in mkdir %d\n",
  			 err);
  		goto error;
  	}
  	name = dentry->d_name.name;
  	err = p9_client_mkdir_dotl(dfid, name, mode, gid, &qid);
  	if (err < 0)
  		goto error;
  	fid = p9_client_walk(dfid, 1, &name, 1);
  	if (IS_ERR(fid)) {
  		err = PTR_ERR(fid);
  		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
  			 err);
  		fid = NULL;
  		goto error;
  	}
  
  	/* instantiate inode and assign the unopened fid to the dentry */
  	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
  		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
  		if (IS_ERR(inode)) {
  			err = PTR_ERR(inode);
  			p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
  				 err);
  			goto error;
  		}
  		v9fs_fid_add(dentry, fid);
  		v9fs_set_create_acl(inode, fid, dacl, pacl);
  		d_instantiate(dentry, inode);
  		fid = NULL;
  		err = 0;
  	} else {
  		/*
  		 * Not in cached mode. No need to populate
  		 * inode with stat. We need to get an inode
  		 * so that we can set the acl with dentry
  		 */
  		inode = v9fs_get_inode(dir->i_sb, mode, 0);
  		if (IS_ERR(inode)) {
  			err = PTR_ERR(inode);
  			goto error;
  		}
  		v9fs_set_create_acl(inode, fid, dacl, pacl);
  		d_instantiate(dentry, inode);
  	}
  	inc_nlink(dir);
  	v9fs_invalidate_inode_attr(dir);
  error:
  	if (fid)
  		p9_client_clunk(fid);
  	v9fs_put_acl(dacl, pacl);
  	p9_client_clunk(dfid);
  	return err;
  }
  
  static int
  v9fs_vfs_getattr_dotl(struct user_namespace *mnt_userns,
  		      const struct path *path, struct kstat *stat,
  		      u32 request_mask, unsigned int flags)
  {
  	struct dentry *dentry = path->dentry;
  	struct v9fs_session_info *v9ses;
  	struct p9_fid *fid;
  	struct p9_stat_dotl *st;
  
  	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
  	v9ses = v9fs_dentry2v9ses(dentry);
  	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
  		generic_fillattr(&init_user_ns, d_inode(dentry), stat);
  		return 0;
  	}
  	fid = v9fs_fid_lookup(dentry);
  	if (IS_ERR(fid))
  		return PTR_ERR(fid);
  
  	/* Ask for all the fields in stat structure. Server will return
  	 * whatever it supports
  	 */
  
  	st = p9_client_getattr_dotl(fid, P9_STATS_ALL);
  	p9_client_clunk(fid);
  	if (IS_ERR(st))
  		return PTR_ERR(st);
  
  	v9fs_stat2inode_dotl(st, d_inode(dentry), 0);
  	generic_fillattr(&init_user_ns, d_inode(dentry), stat);
  	/* Change block size to what the server returned */
  	stat->blksize = st->st_blksize;
  
  	kfree(st);
  	return 0;
  }
  
  /*
   * Attribute flags.
   */
  #define P9_ATTR_MODE		(1 << 0)
  #define P9_ATTR_UID		(1 << 1)
  #define P9_ATTR_GID		(1 << 2)
  #define P9_ATTR_SIZE		(1 << 3)
  #define P9_ATTR_ATIME		(1 << 4)
  #define P9_ATTR_MTIME		(1 << 5)
  #define P9_ATTR_CTIME		(1 << 6)
  #define P9_ATTR_ATIME_SET	(1 << 7)
  #define P9_ATTR_MTIME_SET	(1 << 8)
  
  struct dotl_iattr_map {
  	int iattr_valid;
  	int p9_iattr_valid;
  };
  
  static int v9fs_mapped_iattr_valid(int iattr_valid)
  {
  	int i;
  	int p9_iattr_valid = 0;
  	struct dotl_iattr_map dotl_iattr_map[] = {
  		{ ATTR_MODE,		P9_ATTR_MODE },
  		{ ATTR_UID,		P9_ATTR_UID },
  		{ ATTR_GID,		P9_ATTR_GID },
  		{ ATTR_SIZE,		P9_ATTR_SIZE },
  		{ ATTR_ATIME,		P9_ATTR_ATIME },
  		{ ATTR_MTIME,		P9_ATTR_MTIME },
  		{ ATTR_CTIME,		P9_ATTR_CTIME },
  		{ ATTR_ATIME_SET,	P9_ATTR_ATIME_SET },
  		{ ATTR_MTIME_SET,	P9_ATTR_MTIME_SET },
  	};
  	for (i = 0; i < ARRAY_SIZE(dotl_iattr_map); i++) {
  		if (iattr_valid & dotl_iattr_map[i].iattr_valid)
  			p9_iattr_valid |= dotl_iattr_map[i].p9_iattr_valid;
  	}
  	return p9_iattr_valid;
  }
  
  /**
   * v9fs_vfs_setattr_dotl - set file metadata
   * @mnt_userns: The user namespace of the mount
   * @dentry: file whose metadata to set
   * @iattr: metadata assignment structure
   *
   */
  
  int v9fs_vfs_setattr_dotl(struct user_namespace *mnt_userns,
  			  struct dentry *dentry, struct iattr *iattr)
  {
  	int retval, use_dentry = 0;
  	struct p9_fid *fid = NULL;
  	struct p9_iattr_dotl p9attr = {
  		.uid = INVALID_UID,
  		.gid = INVALID_GID,
  	};
  	struct inode *inode = d_inode(dentry);
  
  	p9_debug(P9_DEBUG_VFS, "\n");
  
  	retval = setattr_prepare(&init_user_ns, dentry, iattr);
  	if (retval)
  		return retval;
  
  	p9attr.valid = v9fs_mapped_iattr_valid(iattr->ia_valid);
  	if (iattr->ia_valid & ATTR_MODE)
  		p9attr.mode = iattr->ia_mode;
  	if (iattr->ia_valid & ATTR_UID)
  		p9attr.uid = iattr->ia_uid;
  	if (iattr->ia_valid & ATTR_GID)
  		p9attr.gid = iattr->ia_gid;
  	if (iattr->ia_valid & ATTR_SIZE)
  		p9attr.size = iattr->ia_size;
  	if (iattr->ia_valid & ATTR_ATIME_SET) {
  		p9attr.atime_sec = iattr->ia_atime.tv_sec;
  		p9attr.atime_nsec = iattr->ia_atime.tv_nsec;
  	}
  	if (iattr->ia_valid & ATTR_MTIME_SET) {
  		p9attr.mtime_sec = iattr->ia_mtime.tv_sec;
  		p9attr.mtime_nsec = iattr->ia_mtime.tv_nsec;
  	}
  
  	if (iattr->ia_valid & ATTR_FILE) {
  		fid = iattr->ia_file->private_data;
  		WARN_ON(!fid);
  	}
  	if (!fid) {
  		fid = v9fs_fid_lookup(dentry);
  		use_dentry = 1;
  	}
  	if (IS_ERR(fid))
  		return PTR_ERR(fid);
  
  	/* Write all dirty data */
  	if (S_ISREG(inode->i_mode))
  		filemap_write_and_wait(inode->i_mapping);
  
  	retval = p9_client_setattr(fid, &p9attr);
  	if (retval < 0) {
  		if (use_dentry)
  			p9_client_clunk(fid);
  		return retval;
  	}
  
  	if ((iattr->ia_valid & ATTR_SIZE) &&
  	    iattr->ia_size != i_size_read(inode))
  		truncate_setsize(inode, iattr->ia_size);
  
  	v9fs_invalidate_inode_attr(inode);
  	setattr_copy(&init_user_ns, inode, iattr);
  	mark_inode_dirty(inode);
  	if (iattr->ia_valid & ATTR_MODE) {
  		/* We also want to update ACL when we update mode bits */
  		retval = v9fs_acl_chmod(inode, fid);
  		if (retval < 0) {
  			if (use_dentry)
  				p9_client_clunk(fid);
  			return retval;
  		}
  	}
  	if (use_dentry)
  		p9_client_clunk(fid);
  
  	return 0;
  }
  
  /**
   * v9fs_stat2inode_dotl - populate an inode structure with stat info
   * @stat: stat structure
   * @inode: inode to populate
   * @flags: ctrl flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
   *
   */
  
  void
  v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
  		      unsigned int flags)
  {
  	umode_t mode;
  	struct v9fs_inode *v9inode = V9FS_I(inode);
  
  	if ((stat->st_result_mask & P9_STATS_BASIC) == P9_STATS_BASIC) {
  		inode->i_atime.tv_sec = stat->st_atime_sec;
  		inode->i_atime.tv_nsec = stat->st_atime_nsec;
  		inode->i_mtime.tv_sec = stat->st_mtime_sec;
  		inode->i_mtime.tv_nsec = stat->st_mtime_nsec;
  		inode->i_ctime.tv_sec = stat->st_ctime_sec;
  		inode->i_ctime.tv_nsec = stat->st_ctime_nsec;
  		inode->i_uid = stat->st_uid;
  		inode->i_gid = stat->st_gid;
  		set_nlink(inode, stat->st_nlink);
  
  		mode = stat->st_mode & S_IALLUGO;
  		mode |= inode->i_mode & ~S_IALLUGO;
  		inode->i_mode = mode;
  
  		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
  			v9fs_i_size_write(inode, stat->st_size);
  		inode->i_blocks = stat->st_blocks;
  	} else {
  		if (stat->st_result_mask & P9_STATS_ATIME) {
  			inode->i_atime.tv_sec = stat->st_atime_sec;
  			inode->i_atime.tv_nsec = stat->st_atime_nsec;
  		}
  		if (stat->st_result_mask & P9_STATS_MTIME) {
  			inode->i_mtime.tv_sec = stat->st_mtime_sec;
  			inode->i_mtime.tv_nsec = stat->st_mtime_nsec;
  		}
  		if (stat->st_result_mask & P9_STATS_CTIME) {
  			inode->i_ctime.tv_sec = stat->st_ctime_sec;
  			inode->i_ctime.tv_nsec = stat->st_ctime_nsec;
  		}
  		if (stat->st_result_mask & P9_STATS_UID)
  			inode->i_uid = stat->st_uid;
  		if (stat->st_result_mask & P9_STATS_GID)
  			inode->i_gid = stat->st_gid;
  		if (stat->st_result_mask & P9_STATS_NLINK)
  			set_nlink(inode, stat->st_nlink);
  		if (stat->st_result_mask & P9_STATS_MODE) {
  			mode = stat->st_mode & S_IALLUGO;
  			mode |= inode->i_mode & ~S_IALLUGO;
  			inode->i_mode = mode;
  		}
  		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE) &&
  		    stat->st_result_mask & P9_STATS_SIZE)
  			v9fs_i_size_write(inode, stat->st_size);
  		if (stat->st_result_mask & P9_STATS_BLOCKS)
  			inode->i_blocks = stat->st_blocks;
  	}
  	if (stat->st_result_mask & P9_STATS_GEN)
  		inode->i_generation = stat->st_gen;
  
  	/* Currently we don't support P9_STATS_BTIME and P9_STATS_DATA_VERSION
  	 * because the inode structure does not have fields for them.
  	 */
  	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
  }
  
  static int
  v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns, struct inode *dir,
  		      struct dentry *dentry, const char *symname)
  {
  	int err;
  	kgid_t gid;
  	const unsigned char *name;
  	struct p9_qid qid;
  	struct inode *inode;
  	struct p9_fid *dfid;
  	struct p9_fid *fid = NULL;
  	struct v9fs_session_info *v9ses;
  
  	name = dentry->d_name.name;
  	p9_debug(P9_DEBUG_VFS, "%lu,%s,%s\n", dir->i_ino, name, symname);
  	v9ses = v9fs_inode2v9ses(dir);
  
  	dfid = v9fs_parent_fid(dentry);
  	if (IS_ERR(dfid)) {
  		err = PTR_ERR(dfid);
  		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
  		return err;
  	}
  
  	gid = v9fs_get_fsgid_for_create(dir);
  
  	/* Server doesn't alter fid on TSYMLINK. Hence no need to clone it. */
  	err = p9_client_symlink(dfid, name, symname, gid, &qid);
  
  	if (err < 0) {
  		p9_debug(P9_DEBUG_VFS, "p9_client_symlink failed %d\n", err);
  		goto error;
  	}
  
  	v9fs_invalidate_inode_attr(dir);
  	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
  		/* Now walk from the parent so we can get an unopened fid. */
  		fid = p9_client_walk(dfid, 1, &name, 1);
  		if (IS_ERR(fid)) {
  			err = PTR_ERR(fid);
  			p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
  				 err);
  			fid = NULL;
  			goto error;
  		}
  
  		/* instantiate inode and assign the unopened fid to dentry */
  		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
  		if (IS_ERR(inode)) {
  			err = PTR_ERR(inode);
  			p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
  				 err);
  			goto error;
  		}
  		v9fs_fid_add(dentry, fid);
  		d_instantiate(dentry, inode);
  		fid = NULL;
  		err = 0;
  	} else {
  		/* Not in cached mode. No need to populate inode with stat */
  		inode = v9fs_get_inode(dir->i_sb, S_IFLNK, 0);
  		if (IS_ERR(inode)) {
  			err = PTR_ERR(inode);
  			goto error;
  		}
  		d_instantiate(dentry, inode);
  	}
  
  error:
  	if (fid)
  		p9_client_clunk(fid);
  
  	p9_client_clunk(dfid);
  	return err;
  }
  
  /**
   * v9fs_vfs_link_dotl - create a hardlink for dotl
   * @old_dentry: dentry for file to link to
   * @dir: inode destination for new link
   * @dentry: dentry for link
   *
   */
  
  static int
  v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
  		struct dentry *dentry)
  {
  	int err;
  	struct p9_fid *dfid, *oldfid;
  	struct v9fs_session_info *v9ses;
  
  	p9_debug(P9_DEBUG_VFS, "dir ino: %lu, old_name: %pd, new_name: %pd\n",
  		 dir->i_ino, old_dentry, dentry);
  
  	v9ses = v9fs_inode2v9ses(dir);
  	dfid = v9fs_parent_fid(dentry);
  	if (IS_ERR(dfid))
  		return PTR_ERR(dfid);
  
  	oldfid = v9fs_fid_lookup(old_dentry);
  	if (IS_ERR(oldfid)) {
  		p9_client_clunk(dfid);
  		return PTR_ERR(oldfid);
  	}
  
  	err = p9_client_link(dfid, oldfid, dentry->d_name.name);
  
  	p9_client_clunk(dfid);
  	p9_client_clunk(oldfid);
  	if (err < 0) {
  		p9_debug(P9_DEBUG_VFS, "p9_client_link failed %d\n", err);
  		return err;
  	}
  
  	v9fs_invalidate_inode_attr(dir);
  	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
  		/* Get the latest stat info from server. */
  		struct p9_fid *fid;
  
  		fid = v9fs_fid_lookup(old_dentry);
  		if (IS_ERR(fid))
  			return PTR_ERR(fid);
  
  		v9fs_refresh_inode_dotl(fid, d_inode(old_dentry));
  		p9_client_clunk(fid);
  	}
  	ihold(d_inode(old_dentry));
  	d_instantiate(dentry, d_inode(old_dentry));
  
  	return err;
  }
  
  /**
   * v9fs_vfs_mknod_dotl - create a special file
   * @mnt_userns: The user namespace of the mount
   * @dir: inode destination for new link
   * @dentry: dentry for file
   * @omode: mode for creation
   * @rdev: device associated with special file
   *
   */
  static int
  v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
  		    struct dentry *dentry, umode_t omode, dev_t rdev)
  {
  	int err;
  	kgid_t gid;
  	const unsigned char *name;
  	umode_t mode;
  	struct v9fs_session_info *v9ses;
  	struct p9_fid *fid = NULL, *dfid = NULL;
  	struct inode *inode;
  	struct p9_qid qid;
  	struct posix_acl *dacl = NULL, *pacl = NULL;
  
  	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
  		 dir->i_ino, dentry, omode,
  		 MAJOR(rdev), MINOR(rdev));
  
  	v9ses = v9fs_inode2v9ses(dir);
  	dfid = v9fs_parent_fid(dentry);
  	if (IS_ERR(dfid)) {
  		err = PTR_ERR(dfid);
  		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
  		dfid = NULL;
  		goto error;
  	}
  
  	gid = v9fs_get_fsgid_for_create(dir);
  	mode = omode;
  	/* Update mode based on ACL value */
  	err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
  	if (err) {
  		p9_debug(P9_DEBUG_VFS, "Failed to get acl values in mknod %d\n",
  			 err);
  		goto error;
  	}
  	name = dentry->d_name.name;
  
  	err = p9_client_mknod_dotl(dfid, name, mode, rdev, gid, &qid);
  	if (err < 0)
  		goto error;
  
  	v9fs_invalidate_inode_attr(dir);
  	fid = p9_client_walk(dfid, 1, &name, 1);
  	if (IS_ERR(fid)) {
  		err = PTR_ERR(fid);
  		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
  			 err);
  		fid = NULL;
  		goto error;
  	}
  
  	/* instantiate inode and assign the unopened fid to the dentry */
  	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
  		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
  		if (IS_ERR(inode)) {
  			err = PTR_ERR(inode);
  			p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
  				 err);
  			goto error;
  		}
  		v9fs_set_create_acl(inode, fid, dacl, pacl);
  		v9fs_fid_add(dentry, fid);
  		d_instantiate(dentry, inode);
  		fid = NULL;
  		err = 0;
  	} else {
  		/*
  		 * Not in cached mode. No need to populate inode with stat.
  		 * socket syscall returns a fd, so we need instantiate
  		 */
  		inode = v9fs_get_inode(dir->i_sb, mode, rdev);
  		if (IS_ERR(inode)) {
  			err = PTR_ERR(inode);
  			goto error;
  		}
  		v9fs_set_create_acl(inode, fid, dacl, pacl);
  		d_instantiate(dentry, inode);
  	}
  error:
  	if (fid)
  		p9_client_clunk(fid);
  	v9fs_put_acl(dacl, pacl);
  	p9_client_clunk(dfid);
  
  	return err;
  }
  
  /**
   * v9fs_vfs_get_link_dotl - follow a symlink path
   * @dentry: dentry for symlink
   * @inode: inode for symlink
   * @done: destructor for return value
   */
  
  static const char *
  v9fs_vfs_get_link_dotl(struct dentry *dentry,
  		       struct inode *inode,
  		       struct delayed_call *done)
  {
  	struct p9_fid *fid;
  	char *target;
  	int retval;
  
  	if (!dentry)
  		return ERR_PTR(-ECHILD);
  
  	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
  
  	fid = v9fs_fid_lookup(dentry);
  	if (IS_ERR(fid))
  		return ERR_CAST(fid);
  	retval = p9_client_readlink(fid, &target);
  	p9_client_clunk(fid);
  	if (retval)
  		return ERR_PTR(retval);
  	set_delayed_call(done, kfree_link, target);
  	return target;
  }
  
  int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
  {
  	struct p9_stat_dotl *st;
  	struct v9fs_session_info *v9ses;
  	unsigned int flags;
  
  	v9ses = v9fs_inode2v9ses(inode);
  	st = p9_client_getattr_dotl(fid, P9_STATS_ALL);
  	if (IS_ERR(st))
  		return PTR_ERR(st);
  	/*
  	 * Don't update inode if the file type is different
  	 */
  	if (inode_wrong_type(inode, st->st_mode))
  		goto out;
  
  	/*
  	 * We don't want to refresh inode->i_size,
  	 * because we may have cached data
  	 */
  	flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
  		V9FS_STAT2INODE_KEEP_ISIZE : 0;
  	v9fs_stat2inode_dotl(st, inode, flags);
  out:
  	kfree(st);
  	return 0;
  }
  
  const struct inode_operations v9fs_dir_inode_operations_dotl = {
  	.create = v9fs_vfs_create_dotl,
  	.atomic_open = v9fs_vfs_atomic_open_dotl,
  	.lookup = v9fs_vfs_lookup,
  	.link = v9fs_vfs_link_dotl,
  	.symlink = v9fs_vfs_symlink_dotl,
  	.unlink = v9fs_vfs_unlink,
  	.mkdir = v9fs_vfs_mkdir_dotl,
  	.rmdir = v9fs_vfs_rmdir,
  	.mknod = v9fs_vfs_mknod_dotl,
  	.rename = v9fs_vfs_rename,
  	.getattr = v9fs_vfs_getattr_dotl,
  	.setattr = v9fs_vfs_setattr_dotl,
  	.listxattr = v9fs_listxattr,
  	.get_acl = v9fs_iop_get_acl,
  };
  
  const struct inode_operations v9fs_file_inode_operations_dotl = {
  	.getattr = v9fs_vfs_getattr_dotl,
  	.setattr = v9fs_vfs_setattr_dotl,
  	.listxattr = v9fs_listxattr,
  	.get_acl = v9fs_iop_get_acl,
  };
  
  const struct inode_operations v9fs_symlink_inode_operations_dotl = {
  	.get_link = v9fs_vfs_get_link_dotl,
  	.getattr = v9fs_vfs_getattr_dotl,
  	.setattr = v9fs_vfs_setattr_dotl,
  	.listxattr = v9fs_listxattr,
  };
  