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v6.13.7
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file contains vfs inode ops for the 9P2000 protocol.
   4 *
   5 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   6 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/module.h>
  12#include <linux/errno.h>
  13#include <linux/fs.h>
  14#include <linux/file.h>
  15#include <linux/pagemap.h>
  16#include <linux/stat.h>
  17#include <linux/string.h>
  18#include <linux/namei.h>
  19#include <linux/sched.h>
  20#include <linux/slab.h>
  21#include <linux/xattr.h>
  22#include <linux/posix_acl.h>
  23#include <net/9p/9p.h>
  24#include <net/9p/client.h>
  25
  26#include "v9fs.h"
  27#include "v9fs_vfs.h"
  28#include "fid.h"
  29#include "cache.h"
  30#include "xattr.h"
  31#include "acl.h"
  32
  33static const struct inode_operations v9fs_dir_inode_operations;
  34static const struct inode_operations v9fs_dir_inode_operations_dotu;
  35static const struct inode_operations v9fs_file_inode_operations;
  36static const struct inode_operations v9fs_symlink_inode_operations;
  37
  38/**
  39 * unixmode2p9mode - convert unix mode bits to plan 9
  40 * @v9ses: v9fs session information
  41 * @mode: mode to convert
  42 *
  43 */
  44
  45static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  46{
  47	int res;
  48
  49	res = mode & 0777;
  50	if (S_ISDIR(mode))
  51		res |= P9_DMDIR;
  52	if (v9fs_proto_dotu(v9ses)) {
  53		if (v9ses->nodev == 0) {
  54			if (S_ISSOCK(mode))
  55				res |= P9_DMSOCKET;
  56			if (S_ISFIFO(mode))
  57				res |= P9_DMNAMEDPIPE;
  58			if (S_ISBLK(mode))
  59				res |= P9_DMDEVICE;
  60			if (S_ISCHR(mode))
  61				res |= P9_DMDEVICE;
  62		}
  63
  64		if ((mode & S_ISUID) == S_ISUID)
  65			res |= P9_DMSETUID;
  66		if ((mode & S_ISGID) == S_ISGID)
  67			res |= P9_DMSETGID;
  68		if ((mode & S_ISVTX) == S_ISVTX)
  69			res |= P9_DMSETVTX;
  70	}
  71	return res;
  72}
  73
  74/**
  75 * p9mode2perm- convert plan9 mode bits to unix permission bits
  76 * @v9ses: v9fs session information
  77 * @stat: p9_wstat from which mode need to be derived
  78 *
  79 */
  80static int p9mode2perm(struct v9fs_session_info *v9ses,
  81		       struct p9_wstat *stat)
  82{
  83	int res;
  84	int mode = stat->mode;
  85
  86	res = mode & 0777; /* S_IRWXUGO */
  87	if (v9fs_proto_dotu(v9ses)) {
  88		if ((mode & P9_DMSETUID) == P9_DMSETUID)
  89			res |= S_ISUID;
  90
  91		if ((mode & P9_DMSETGID) == P9_DMSETGID)
  92			res |= S_ISGID;
  93
  94		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
  95			res |= S_ISVTX;
  96	}
  97	return res;
  98}
  99
 100/**
 101 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 102 * @v9ses: v9fs session information
 103 * @stat: p9_wstat from which mode need to be derived
 104 * @rdev: major number, minor number in case of device files.
 105 *
 106 */
 107static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 108			       struct p9_wstat *stat, dev_t *rdev)
 109{
 110	int res, r;
 111	u32 mode = stat->mode;
 112
 113	*rdev = 0;
 114	res = p9mode2perm(v9ses, stat);
 115
 116	if ((mode & P9_DMDIR) == P9_DMDIR)
 117		res |= S_IFDIR;
 118	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 119		res |= S_IFLNK;
 120	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 121		 && (v9ses->nodev == 0))
 122		res |= S_IFSOCK;
 123	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 124		 && (v9ses->nodev == 0))
 125		res |= S_IFIFO;
 126	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 127		 && (v9ses->nodev == 0)) {
 128		char type = 0;
 129		int major = -1, minor = -1;
 130
 131		r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
 132		if (r != 3) {
 133			p9_debug(P9_DEBUG_ERROR,
 134				 "invalid device string, umode will be bogus: %s\n",
 135				 stat->extension);
 136			return res;
 137		}
 138		switch (type) {
 139		case 'c':
 140			res |= S_IFCHR;
 141			break;
 142		case 'b':
 143			res |= S_IFBLK;
 144			break;
 145		default:
 146			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 147				 type, stat->extension);
 148		}
 149		*rdev = MKDEV(major, minor);
 150	} else
 151		res |= S_IFREG;
 152
 153	return res;
 154}
 155
 156/**
 157 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 158 * @uflags: flags to convert
 159 * @extended: if .u extensions are active
 160 */
 161
 162int v9fs_uflags2omode(int uflags, int extended)
 163{
 164	int ret;
 165
 166	switch (uflags&3) {
 167	default:
 168	case O_RDONLY:
 169		ret = P9_OREAD;
 170		break;
 171
 172	case O_WRONLY:
 173		ret = P9_OWRITE;
 174		break;
 175
 176	case O_RDWR:
 177		ret = P9_ORDWR;
 178		break;
 179	}
 180
 181	if (uflags & O_TRUNC)
 182		ret |= P9_OTRUNC;
 183
 184	if (extended) {
 185		if (uflags & O_EXCL)
 186			ret |= P9_OEXCL;
 187
 188		if (uflags & O_APPEND)
 189			ret |= P9_OAPPEND;
 190	}
 191
 192	return ret;
 193}
 194
 195/**
 196 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 197 * @wstat: structure to initialize
 198 *
 199 */
 200
 201void
 202v9fs_blank_wstat(struct p9_wstat *wstat)
 203{
 204	wstat->type = ~0;
 205	wstat->dev = ~0;
 206	wstat->qid.type = ~0;
 207	wstat->qid.version = ~0;
 208	*((long long *)&wstat->qid.path) = ~0;
 209	wstat->mode = ~0;
 210	wstat->atime = ~0;
 211	wstat->mtime = ~0;
 212	wstat->length = ~0;
 213	wstat->name = NULL;
 214	wstat->uid = NULL;
 215	wstat->gid = NULL;
 216	wstat->muid = NULL;
 217	wstat->n_uid = INVALID_UID;
 218	wstat->n_gid = INVALID_GID;
 219	wstat->n_muid = INVALID_UID;
 220	wstat->extension = NULL;
 221}
 222
 223/**
 224 * v9fs_alloc_inode - helper function to allocate an inode
 225 * @sb: The superblock to allocate the inode from
 226 */
 227struct inode *v9fs_alloc_inode(struct super_block *sb)
 228{
 229	struct v9fs_inode *v9inode;
 230
 231	v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
 232	if (!v9inode)
 233		return NULL;
 234	v9inode->cache_validity = 0;
 235	mutex_init(&v9inode->v_mutex);
 236	return &v9inode->netfs.inode;
 237}
 238
 239/**
 240 * v9fs_free_inode - destroy an inode
 241 * @inode: The inode to be freed
 242 */
 243
 244void v9fs_free_inode(struct inode *inode)
 245{
 246	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 247}
 248
 249/*
 250 * Set parameters for the netfs library
 251 */
 252void v9fs_set_netfs_context(struct inode *inode)
 253{
 254	struct v9fs_inode *v9inode = V9FS_I(inode);
 255	netfs_inode_init(&v9inode->netfs, &v9fs_req_ops, true);
 256}
 257
 258int v9fs_init_inode(struct v9fs_session_info *v9ses,
 259		    struct inode *inode, umode_t mode, dev_t rdev)
 260{
 261	int err = 0;
 262
 263	inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
 264	inode->i_blocks = 0;
 265	inode->i_rdev = rdev;
 266	simple_inode_init_ts(inode);
 267	inode->i_mapping->a_ops = &v9fs_addr_operations;
 268	inode->i_private = NULL;
 269
 270	switch (mode & S_IFMT) {
 271	case S_IFIFO:
 272	case S_IFBLK:
 273	case S_IFCHR:
 274	case S_IFSOCK:
 275		if (v9fs_proto_dotl(v9ses)) {
 276			inode->i_op = &v9fs_file_inode_operations_dotl;
 277		} else if (v9fs_proto_dotu(v9ses)) {
 278			inode->i_op = &v9fs_file_inode_operations;
 279		} else {
 280			p9_debug(P9_DEBUG_ERROR,
 281				 "special files without extended mode\n");
 282			err = -EINVAL;
 283			goto error;
 284		}
 285		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 286		break;
 287	case S_IFREG:
 288		if (v9fs_proto_dotl(v9ses)) {
 289			inode->i_op = &v9fs_file_inode_operations_dotl;
 290			inode->i_fop = &v9fs_file_operations_dotl;
 291		} else {
 292			inode->i_op = &v9fs_file_inode_operations;
 293			inode->i_fop = &v9fs_file_operations;
 294		}
 295
 296		break;
 297	case S_IFLNK:
 298		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 299			p9_debug(P9_DEBUG_ERROR,
 300				 "extended modes used with legacy protocol\n");
 301			err = -EINVAL;
 302			goto error;
 303		}
 304
 305		if (v9fs_proto_dotl(v9ses))
 306			inode->i_op = &v9fs_symlink_inode_operations_dotl;
 307		else
 308			inode->i_op = &v9fs_symlink_inode_operations;
 309
 310		break;
 311	case S_IFDIR:
 312		inc_nlink(inode);
 313		if (v9fs_proto_dotl(v9ses))
 314			inode->i_op = &v9fs_dir_inode_operations_dotl;
 315		else if (v9fs_proto_dotu(v9ses))
 316			inode->i_op = &v9fs_dir_inode_operations_dotu;
 317		else
 318			inode->i_op = &v9fs_dir_inode_operations;
 319
 320		if (v9fs_proto_dotl(v9ses))
 321			inode->i_fop = &v9fs_dir_operations_dotl;
 322		else
 323			inode->i_fop = &v9fs_dir_operations;
 324
 325		break;
 326	default:
 327		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 328			 mode, mode & S_IFMT);
 329		err = -EINVAL;
 330		goto error;
 331	}
 332error:
 333	return err;
 334
 335}
 336
 337/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 338 * v9fs_evict_inode - Remove an inode from the inode cache
 339 * @inode: inode to release
 340 *
 341 */
 342void v9fs_evict_inode(struct inode *inode)
 343{
 344	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
 345	__le32 __maybe_unused version;
 346
 347	if (!is_bad_inode(inode)) {
 348		netfs_wait_for_outstanding_io(inode);
 349		truncate_inode_pages_final(&inode->i_data);
 350
 351		version = cpu_to_le32(v9inode->qid.version);
 352		netfs_clear_inode_writeback(inode, &version);
 353
 354		clear_inode(inode);
 355		filemap_fdatawrite(&inode->i_data);
 356
 357#ifdef CONFIG_9P_FSCACHE
 358		if (v9fs_inode_cookie(v9inode))
 359			fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
 360#endif
 361	} else
 362		clear_inode(inode);
 363}
 364
 365static int v9fs_test_inode(struct inode *inode, void *data)
 366{
 367	int umode;
 368	dev_t rdev;
 369	struct v9fs_inode *v9inode = V9FS_I(inode);
 370	struct p9_wstat *st = (struct p9_wstat *)data;
 371	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 372
 373	umode = p9mode2unixmode(v9ses, st, &rdev);
 374	/* don't match inode of different type */
 375	if (inode_wrong_type(inode, umode))
 376		return 0;
 377
 378	/* compare qid details */
 379	if (memcmp(&v9inode->qid.version,
 380		   &st->qid.version, sizeof(v9inode->qid.version)))
 381		return 0;
 382
 383	if (v9inode->qid.type != st->qid.type)
 384		return 0;
 385
 386	if (v9inode->qid.path != st->qid.path)
 387		return 0;
 388	return 1;
 389}
 390
 391static int v9fs_test_new_inode(struct inode *inode, void *data)
 392{
 393	return 0;
 394}
 395
 396static int v9fs_set_inode(struct inode *inode,  void *data)
 397{
 398	struct v9fs_inode *v9inode = V9FS_I(inode);
 399	struct p9_wstat *st = (struct p9_wstat *)data;
 400
 401	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 402	return 0;
 403}
 404
 405static struct inode *v9fs_qid_iget(struct super_block *sb,
 406				   struct p9_qid *qid,
 407				   struct p9_wstat *st,
 408				   int new)
 409{
 410	dev_t rdev;
 411	int retval;
 412	umode_t umode;
 
 413	struct inode *inode;
 414	struct v9fs_session_info *v9ses = sb->s_fs_info;
 415	int (*test)(struct inode *inode, void *data);
 416
 417	if (new)
 418		test = v9fs_test_new_inode;
 419	else
 420		test = v9fs_test_inode;
 421
 422	inode = iget5_locked(sb, QID2INO(qid), test, v9fs_set_inode, st);
 
 423	if (!inode)
 424		return ERR_PTR(-ENOMEM);
 425	if (!(inode->i_state & I_NEW))
 426		return inode;
 427	/*
 428	 * initialize the inode with the stat info
 429	 * FIXME!! we may need support for stale inodes
 430	 * later.
 431	 */
 432	inode->i_ino = QID2INO(qid);
 433	umode = p9mode2unixmode(v9ses, st, &rdev);
 434	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 435	if (retval)
 436		goto error;
 437
 438	v9fs_stat2inode(st, inode, sb, 0);
 439	v9fs_set_netfs_context(inode);
 440	v9fs_cache_inode_get_cookie(inode);
 441	unlock_new_inode(inode);
 442	return inode;
 443error:
 444	iget_failed(inode);
 445	return ERR_PTR(retval);
 446
 447}
 448
 449struct inode *
 450v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 451		    struct super_block *sb, int new)
 452{
 453	struct p9_wstat *st;
 454	struct inode *inode = NULL;
 455
 456	st = p9_client_stat(fid);
 457	if (IS_ERR(st))
 458		return ERR_CAST(st);
 459
 460	inode = v9fs_qid_iget(sb, &st->qid, st, new);
 461	p9stat_free(st);
 462	kfree(st);
 463	return inode;
 464}
 465
 466/**
 467 * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 468 * plan 9 AT flag.
 469 * @flags: flags to convert
 470 */
 471static int v9fs_at_to_dotl_flags(int flags)
 472{
 473	int rflags = 0;
 474
 475	if (flags & AT_REMOVEDIR)
 476		rflags |= P9_DOTL_AT_REMOVEDIR;
 477
 478	return rflags;
 479}
 480
 481/**
 482 * v9fs_dec_count - helper functon to drop i_nlink.
 483 *
 484 * If a directory had nlink <= 2 (including . and ..), then we should not drop
 485 * the link count, which indicates the underlying exported fs doesn't maintain
 486 * nlink accurately. e.g.
 487 * - overlayfs sets nlink to 1 for merged dir
 488 * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
 489 *   than EXT4_LINK_MAX (65000) links.
 490 *
 491 * @inode: inode whose nlink is being dropped
 492 */
 493static void v9fs_dec_count(struct inode *inode)
 494{
 495	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
 496		drop_nlink(inode);
 497}
 498
 499/**
 500 * v9fs_remove - helper function to remove files and directories
 501 * @dir: directory inode that is being deleted
 502 * @dentry:  dentry that is being deleted
 503 * @flags: removing a directory
 504 *
 505 */
 506
 507static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 508{
 509	struct inode *inode;
 510	int retval = -EOPNOTSUPP;
 511	struct p9_fid *v9fid, *dfid;
 512	struct v9fs_session_info *v9ses;
 513
 514	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 515		 dir, dentry, flags);
 516
 517	v9ses = v9fs_inode2v9ses(dir);
 518	inode = d_inode(dentry);
 519	dfid = v9fs_parent_fid(dentry);
 520	if (IS_ERR(dfid)) {
 521		retval = PTR_ERR(dfid);
 522		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 523		return retval;
 524	}
 525	if (v9fs_proto_dotl(v9ses))
 526		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 527					    v9fs_at_to_dotl_flags(flags));
 528	p9_fid_put(dfid);
 529	if (retval == -EOPNOTSUPP) {
 530		/* Try the one based on path */
 531		v9fid = v9fs_fid_clone(dentry);
 532		if (IS_ERR(v9fid))
 533			return PTR_ERR(v9fid);
 534		retval = p9_client_remove(v9fid);
 535	}
 536	if (!retval) {
 537		/*
 538		 * directories on unlink should have zero
 539		 * link count
 540		 */
 541		if (flags & AT_REMOVEDIR) {
 542			clear_nlink(inode);
 543			v9fs_dec_count(dir);
 544		} else
 545			v9fs_dec_count(inode);
 546
 547		v9fs_invalidate_inode_attr(inode);
 548		v9fs_invalidate_inode_attr(dir);
 549
 550		/* invalidate all fids associated with dentry */
 551		/* NOTE: This will not include open fids */
 552		dentry->d_op->d_release(dentry);
 553	}
 554	return retval;
 555}
 556
 557/**
 558 * v9fs_create - Create a file
 559 * @v9ses: session information
 560 * @dir: directory that dentry is being created in
 561 * @dentry:  dentry that is being created
 562 * @extension: 9p2000.u extension string to support devices, etc.
 563 * @perm: create permissions
 564 * @mode: open mode
 565 *
 566 */
 567static struct p9_fid *
 568v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 569		struct dentry *dentry, char *extension, u32 perm, u8 mode)
 570{
 571	int err;
 572	const unsigned char *name;
 573	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
 574	struct inode *inode;
 575
 576	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 577
 578	name = dentry->d_name.name;
 579	dfid = v9fs_parent_fid(dentry);
 580	if (IS_ERR(dfid)) {
 581		err = PTR_ERR(dfid);
 582		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 583		return ERR_PTR(err);
 584	}
 585
 586	/* clone a fid to use for creation */
 587	ofid = clone_fid(dfid);
 588	if (IS_ERR(ofid)) {
 589		err = PTR_ERR(ofid);
 590		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 591		goto error;
 592	}
 593
 594	err = p9_client_fcreate(ofid, name, perm, mode, extension);
 595	if (err < 0) {
 596		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 597		goto error;
 598	}
 599
 600	if (!(perm & P9_DMLINK)) {
 601		/* now walk from the parent so we can get unopened fid */
 602		fid = p9_client_walk(dfid, 1, &name, 1);
 603		if (IS_ERR(fid)) {
 604			err = PTR_ERR(fid);
 605			p9_debug(P9_DEBUG_VFS,
 606				   "p9_client_walk failed %d\n", err);
 607			goto error;
 608		}
 609		/*
 610		 * instantiate inode and assign the unopened fid to the dentry
 611		 */
 612		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 613		if (IS_ERR(inode)) {
 614			err = PTR_ERR(inode);
 615			p9_debug(P9_DEBUG_VFS,
 616				   "inode creation failed %d\n", err);
 617			goto error;
 618		}
 619		v9fs_fid_add(dentry, &fid);
 620		d_instantiate(dentry, inode);
 621	}
 622	p9_fid_put(dfid);
 623	return ofid;
 624error:
 625	p9_fid_put(dfid);
 626	p9_fid_put(ofid);
 627	p9_fid_put(fid);
 628	return ERR_PTR(err);
 629}
 630
 631/**
 632 * v9fs_vfs_create - VFS hook to create a regular file
 633 * @idmap: idmap of the mount
 634 * @dir: The parent directory
 635 * @dentry: The name of file to be created
 636 * @mode: The UNIX file mode to set
 637 * @excl: True if the file must not yet exist
 638 *
 639 * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 640 * for mknod(2).
 641 *
 642 */
 643
 644static int
 645v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
 646		struct dentry *dentry, umode_t mode, bool excl)
 647{
 648	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 649	u32 perm = unixmode2p9mode(v9ses, mode);
 650	struct p9_fid *fid;
 651
 652	/* P9_OEXCL? */
 653	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 654	if (IS_ERR(fid))
 655		return PTR_ERR(fid);
 656
 657	v9fs_invalidate_inode_attr(dir);
 658	p9_fid_put(fid);
 659
 660	return 0;
 661}
 662
 663/**
 664 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 665 * @idmap: idmap of the mount
 666 * @dir:  inode that is being unlinked
 667 * @dentry: dentry that is being unlinked
 668 * @mode: mode for new directory
 669 *
 670 */
 671
 672static int v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 673			  struct dentry *dentry, umode_t mode)
 674{
 675	int err;
 676	u32 perm;
 677	struct p9_fid *fid;
 678	struct v9fs_session_info *v9ses;
 679
 680	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 681	err = 0;
 682	v9ses = v9fs_inode2v9ses(dir);
 683	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 684	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 685	if (IS_ERR(fid)) {
 686		err = PTR_ERR(fid);
 687		fid = NULL;
 688	} else {
 689		inc_nlink(dir);
 690		v9fs_invalidate_inode_attr(dir);
 691	}
 692
 693	if (fid)
 694		p9_fid_put(fid);
 695
 696	return err;
 697}
 698
 699/**
 700 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 701 * @dir:  inode that is being walked from
 702 * @dentry: dentry that is being walked to?
 703 * @flags: lookup flags (unused)
 704 *
 705 */
 706
 707struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 708				      unsigned int flags)
 709{
 710	struct dentry *res;
 711	struct v9fs_session_info *v9ses;
 712	struct p9_fid *dfid, *fid;
 713	struct inode *inode;
 714	const unsigned char *name;
 715
 716	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 717		 dir, dentry, dentry, flags);
 718
 719	if (dentry->d_name.len > NAME_MAX)
 720		return ERR_PTR(-ENAMETOOLONG);
 721
 722	v9ses = v9fs_inode2v9ses(dir);
 723	/* We can walk d_parent because we hold the dir->i_mutex */
 724	dfid = v9fs_parent_fid(dentry);
 725	if (IS_ERR(dfid))
 726		return ERR_CAST(dfid);
 727
 728	/*
 729	 * Make sure we don't use a wrong inode due to parallel
 730	 * unlink. For cached mode create calls request for new
 731	 * inode. But with cache disabled, lookup should do this.
 732	 */
 733	name = dentry->d_name.name;
 734	fid = p9_client_walk(dfid, 1, &name, 1);
 735	p9_fid_put(dfid);
 736	if (fid == ERR_PTR(-ENOENT))
 737		inode = NULL;
 738	else if (IS_ERR(fid))
 739		inode = ERR_CAST(fid);
 740	else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 741		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 742	else
 743		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 744	/*
 745	 * If we had a rename on the server and a parallel lookup
 746	 * for the new name, then make sure we instantiate with
 747	 * the new name. ie look up for a/b, while on server somebody
 748	 * moved b under k and client parallely did a lookup for
 749	 * k/b.
 750	 */
 751	res = d_splice_alias(inode, dentry);
 752	if (!IS_ERR(fid)) {
 753		if (!res)
 754			v9fs_fid_add(dentry, &fid);
 755		else if (!IS_ERR(res))
 756			v9fs_fid_add(res, &fid);
 757		else
 758			p9_fid_put(fid);
 759	}
 760	return res;
 761}
 762
 763static int
 764v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 765		     struct file *file, unsigned int flags, umode_t mode)
 766{
 767	int err;
 768	u32 perm;
 769	struct v9fs_inode __maybe_unused *v9inode;
 770	struct v9fs_session_info *v9ses;
 771	struct p9_fid *fid;
 772	struct dentry *res = NULL;
 773	struct inode *inode;
 774	int p9_omode;
 775
 776	if (d_in_lookup(dentry)) {
 777		res = v9fs_vfs_lookup(dir, dentry, 0);
 778		if (IS_ERR(res))
 779			return PTR_ERR(res);
 780
 781		if (res)
 782			dentry = res;
 783	}
 784
 785	/* Only creates */
 786	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 787		return finish_no_open(file, res);
 788
 789	v9ses = v9fs_inode2v9ses(dir);
 790	perm = unixmode2p9mode(v9ses, mode);
 791	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
 792
 793	if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
 794		p9_omode = (p9_omode & ~P9_OWRITE) | P9_ORDWR;
 795		p9_debug(P9_DEBUG_CACHE,
 796			"write-only file with writeback enabled, creating w/ O_RDWR\n");
 797	}
 798	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
 799	if (IS_ERR(fid)) {
 800		err = PTR_ERR(fid);
 801		goto error;
 802	}
 803
 804	v9fs_invalidate_inode_attr(dir);
 805	inode = d_inode(dentry);
 806	v9inode = V9FS_I(inode);
 807	err = finish_open(file, dentry, generic_file_open);
 808	if (err)
 809		goto error;
 810
 811	file->private_data = fid;
 812#ifdef CONFIG_9P_FSCACHE
 813	if (v9ses->cache & CACHE_FSCACHE)
 814		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 815				   file->f_mode & FMODE_WRITE);
 816#endif
 817
 818	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
 819	v9fs_open_fid_add(inode, &fid);
 820
 821	file->f_mode |= FMODE_CREATED;
 822out:
 823	dput(res);
 824	return err;
 825
 826error:
 827	p9_fid_put(fid);
 828	goto out;
 829}
 830
 831/**
 832 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 833 * @i:  inode that is being unlinked
 834 * @d: dentry that is being unlinked
 835 *
 836 */
 837
 838int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 839{
 840	return v9fs_remove(i, d, 0);
 841}
 842
 843/**
 844 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 845 * @i:  inode that is being unlinked
 846 * @d: dentry that is being unlinked
 847 *
 848 */
 849
 850int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 851{
 852	return v9fs_remove(i, d, AT_REMOVEDIR);
 853}
 854
 855/**
 856 * v9fs_vfs_rename - VFS hook to rename an inode
 857 * @idmap: The idmap of the mount
 858 * @old_dir:  old dir inode
 859 * @old_dentry: old dentry
 860 * @new_dir: new dir inode
 861 * @new_dentry: new dentry
 862 * @flags: RENAME_* flags
 863 *
 864 */
 865
 866int
 867v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 868		struct dentry *old_dentry, struct inode *new_dir,
 869		struct dentry *new_dentry, unsigned int flags)
 870{
 871	int retval;
 872	struct inode *old_inode;
 873	struct inode *new_inode;
 874	struct v9fs_session_info *v9ses;
 875	struct p9_fid *oldfid = NULL, *dfid = NULL;
 876	struct p9_fid *olddirfid = NULL;
 877	struct p9_fid *newdirfid = NULL;
 878	struct p9_wstat wstat;
 879
 880	if (flags)
 881		return -EINVAL;
 882
 883	p9_debug(P9_DEBUG_VFS, "\n");
 884	old_inode = d_inode(old_dentry);
 885	new_inode = d_inode(new_dentry);
 886	v9ses = v9fs_inode2v9ses(old_inode);
 887	oldfid = v9fs_fid_lookup(old_dentry);
 888	if (IS_ERR(oldfid))
 889		return PTR_ERR(oldfid);
 890
 891	dfid = v9fs_parent_fid(old_dentry);
 892	olddirfid = clone_fid(dfid);
 893	p9_fid_put(dfid);
 894	dfid = NULL;
 895
 896	if (IS_ERR(olddirfid)) {
 897		retval = PTR_ERR(olddirfid);
 898		goto error;
 899	}
 900
 901	dfid = v9fs_parent_fid(new_dentry);
 902	newdirfid = clone_fid(dfid);
 903	p9_fid_put(dfid);
 904	dfid = NULL;
 905
 906	if (IS_ERR(newdirfid)) {
 907		retval = PTR_ERR(newdirfid);
 908		goto error;
 909	}
 910
 911	down_write(&v9ses->rename_sem);
 912	if (v9fs_proto_dotl(v9ses)) {
 913		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 914					    newdirfid, new_dentry->d_name.name);
 915		if (retval == -EOPNOTSUPP)
 916			retval = p9_client_rename(oldfid, newdirfid,
 917						  new_dentry->d_name.name);
 918		if (retval != -EOPNOTSUPP)
 919			goto error_locked;
 920	}
 921	if (old_dentry->d_parent != new_dentry->d_parent) {
 922		/*
 923		 * 9P .u can only handle file rename in the same directory
 924		 */
 925
 926		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
 927		retval = -EXDEV;
 928		goto error_locked;
 929	}
 930	v9fs_blank_wstat(&wstat);
 931	wstat.muid = v9ses->uname;
 932	wstat.name = new_dentry->d_name.name;
 933	retval = p9_client_wstat(oldfid, &wstat);
 934
 935error_locked:
 936	if (!retval) {
 937		if (new_inode) {
 938			if (S_ISDIR(new_inode->i_mode))
 939				clear_nlink(new_inode);
 940			else
 941				v9fs_dec_count(new_inode);
 942		}
 943		if (S_ISDIR(old_inode->i_mode)) {
 944			if (!new_inode)
 945				inc_nlink(new_dir);
 946			v9fs_dec_count(old_dir);
 947		}
 948		v9fs_invalidate_inode_attr(old_inode);
 949		v9fs_invalidate_inode_attr(old_dir);
 950		v9fs_invalidate_inode_attr(new_dir);
 951
 952		/* successful rename */
 953		d_move(old_dentry, new_dentry);
 954	}
 955	up_write(&v9ses->rename_sem);
 956
 957error:
 958	p9_fid_put(newdirfid);
 959	p9_fid_put(olddirfid);
 960	p9_fid_put(oldfid);
 961	return retval;
 962}
 963
 964/**
 965 * v9fs_vfs_getattr - retrieve file metadata
 966 * @idmap: idmap of the mount
 967 * @path: Object to query
 968 * @stat: metadata structure to populate
 969 * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
 970 * @flags: AT_STATX_xxx setting
 971 *
 972 */
 973
 974static int
 975v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
 976		 struct kstat *stat, u32 request_mask, unsigned int flags)
 977{
 978	struct dentry *dentry = path->dentry;
 979	struct inode *inode = d_inode(dentry);
 980	struct v9fs_session_info *v9ses;
 981	struct p9_fid *fid;
 982	struct p9_wstat *st;
 983
 984	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 985	v9ses = v9fs_dentry2v9ses(dentry);
 986	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
 987		generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
 988		return 0;
 989	} else if (v9ses->cache & CACHE_WRITEBACK) {
 990		if (S_ISREG(inode->i_mode)) {
 991			int retval = filemap_fdatawrite(inode->i_mapping);
 992
 993			if (retval)
 994				p9_debug(P9_DEBUG_ERROR,
 995				    "flushing writeback during getattr returned %d\n", retval);
 996		}
 997	}
 998	fid = v9fs_fid_lookup(dentry);
 999	if (IS_ERR(fid))
1000		return PTR_ERR(fid);
1001
1002	st = p9_client_stat(fid);
1003	p9_fid_put(fid);
1004	if (IS_ERR(st))
1005		return PTR_ERR(st);
1006
1007	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1008	generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
1009
1010	p9stat_free(st);
1011	kfree(st);
1012	return 0;
1013}
1014
1015/**
1016 * v9fs_vfs_setattr - set file metadata
1017 * @idmap: idmap of the mount
1018 * @dentry: file whose metadata to set
1019 * @iattr: metadata assignment structure
1020 *
1021 */
1022
1023static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
1024			    struct dentry *dentry, struct iattr *iattr)
1025{
1026	int retval, use_dentry = 0;
1027	struct inode *inode = d_inode(dentry);
1028	struct v9fs_session_info *v9ses;
1029	struct p9_fid *fid = NULL;
1030	struct p9_wstat wstat;
1031
1032	p9_debug(P9_DEBUG_VFS, "\n");
1033	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1034	if (retval)
1035		return retval;
1036
1037	v9ses = v9fs_dentry2v9ses(dentry);
1038	if (iattr->ia_valid & ATTR_FILE) {
1039		fid = iattr->ia_file->private_data;
1040		WARN_ON(!fid);
1041	}
1042	if (!fid) {
1043		fid = v9fs_fid_lookup(dentry);
1044		use_dentry = 1;
1045	}
1046	if (IS_ERR(fid))
1047		return PTR_ERR(fid);
1048
1049	v9fs_blank_wstat(&wstat);
1050	if (iattr->ia_valid & ATTR_MODE)
1051		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1052
1053	if (iattr->ia_valid & ATTR_MTIME)
1054		wstat.mtime = iattr->ia_mtime.tv_sec;
1055
1056	if (iattr->ia_valid & ATTR_ATIME)
1057		wstat.atime = iattr->ia_atime.tv_sec;
1058
1059	if (iattr->ia_valid & ATTR_SIZE)
1060		wstat.length = iattr->ia_size;
1061
1062	if (v9fs_proto_dotu(v9ses)) {
1063		if (iattr->ia_valid & ATTR_UID)
1064			wstat.n_uid = iattr->ia_uid;
1065
1066		if (iattr->ia_valid & ATTR_GID)
1067			wstat.n_gid = iattr->ia_gid;
1068	}
1069
1070	/* Write all dirty data */
1071	if (d_is_reg(dentry)) {
1072		retval = filemap_fdatawrite(inode->i_mapping);
1073		if (retval)
1074			p9_debug(P9_DEBUG_ERROR,
1075			    "flushing writeback during setattr returned %d\n", retval);
1076	}
1077
1078	retval = p9_client_wstat(fid, &wstat);
1079
1080	if (use_dentry)
1081		p9_fid_put(fid);
1082
1083	if (retval < 0)
1084		return retval;
1085
1086	if ((iattr->ia_valid & ATTR_SIZE) &&
1087		 iattr->ia_size != i_size_read(inode)) {
1088		truncate_setsize(inode, iattr->ia_size);
1089		netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
1090
1091#ifdef CONFIG_9P_FSCACHE
1092		if (v9ses->cache & CACHE_FSCACHE) {
1093			struct v9fs_inode *v9inode = V9FS_I(inode);
1094
1095			fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
1096		}
1097#endif
1098	}
1099
1100	v9fs_invalidate_inode_attr(inode);
1101
1102	setattr_copy(&nop_mnt_idmap, inode, iattr);
1103	mark_inode_dirty(inode);
1104	return 0;
1105}
1106
1107/**
1108 * v9fs_stat2inode - populate an inode structure with mistat info
1109 * @stat: Plan 9 metadata (mistat) structure
1110 * @inode: inode to populate
1111 * @sb: superblock of filesystem
1112 * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1113 *
1114 */
1115
1116void
1117v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1118		 struct super_block *sb, unsigned int flags)
1119{
1120	umode_t mode;
1121	struct v9fs_session_info *v9ses = sb->s_fs_info;
1122	struct v9fs_inode *v9inode = V9FS_I(inode);
1123
 
 
1124	inode_set_atime(inode, stat->atime, 0);
1125	inode_set_mtime(inode, stat->mtime, 0);
1126	inode_set_ctime(inode, stat->mtime, 0);
1127
1128	inode->i_uid = v9ses->dfltuid;
1129	inode->i_gid = v9ses->dfltgid;
1130
1131	if (v9fs_proto_dotu(v9ses)) {
1132		inode->i_uid = stat->n_uid;
1133		inode->i_gid = stat->n_gid;
1134	}
1135	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1136		if (v9fs_proto_dotu(v9ses)) {
1137			unsigned int i_nlink;
1138			/*
1139			 * Hadlink support got added later to the .u extension.
1140			 * So there can be a server out there that doesn't
1141			 * support this even with .u extension. That would
1142			 * just leave us with stat->extension being an empty
1143			 * string, though.
1144			 */
1145			/* HARDLINKCOUNT %u */
1146			if (sscanf(stat->extension,
1147				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1148				set_nlink(inode, i_nlink);
1149		}
1150	}
1151	mode = p9mode2perm(v9ses, stat);
1152	mode |= inode->i_mode & ~S_IALLUGO;
1153	inode->i_mode = mode;
1154
1155	v9inode->netfs.remote_i_size = stat->length;
1156	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1157		v9fs_i_size_write(inode, stat->length);
1158	/* not real number of blocks, but 512 byte ones ... */
1159	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1160	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1161}
1162
1163/**
1164 * v9fs_vfs_get_link - follow a symlink path
1165 * @dentry: dentry for symlink
1166 * @inode: inode for symlink
1167 * @done: delayed call for when we are done with the return value
1168 */
1169
1170static const char *v9fs_vfs_get_link(struct dentry *dentry,
1171				     struct inode *inode,
1172				     struct delayed_call *done)
1173{
1174	struct v9fs_session_info *v9ses;
1175	struct p9_fid *fid;
1176	struct p9_wstat *st;
1177	char *res;
1178
1179	if (!dentry)
1180		return ERR_PTR(-ECHILD);
1181
1182	v9ses = v9fs_dentry2v9ses(dentry);
1183	if (!v9fs_proto_dotu(v9ses))
1184		return ERR_PTR(-EBADF);
1185
1186	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1187	fid = v9fs_fid_lookup(dentry);
1188
1189	if (IS_ERR(fid))
1190		return ERR_CAST(fid);
1191
1192	st = p9_client_stat(fid);
1193	p9_fid_put(fid);
1194	if (IS_ERR(st))
1195		return ERR_CAST(st);
1196
1197	if (!(st->mode & P9_DMSYMLINK)) {
1198		p9stat_free(st);
1199		kfree(st);
1200		return ERR_PTR(-EINVAL);
1201	}
1202	res = st->extension;
1203	st->extension = NULL;
1204	if (strlen(res) >= PATH_MAX)
1205		res[PATH_MAX - 1] = '\0';
1206
1207	p9stat_free(st);
1208	kfree(st);
1209	set_delayed_call(done, kfree_link, res);
1210	return res;
1211}
1212
1213/**
1214 * v9fs_vfs_mkspecial - create a special file
1215 * @dir: inode to create special file in
1216 * @dentry: dentry to create
1217 * @perm: mode to create special file
1218 * @extension: 9p2000.u format extension string representing special file
1219 *
1220 */
1221
1222static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1223	u32 perm, const char *extension)
1224{
1225	struct p9_fid *fid;
1226	struct v9fs_session_info *v9ses;
1227
1228	v9ses = v9fs_inode2v9ses(dir);
1229	if (!v9fs_proto_dotu(v9ses)) {
1230		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1231		return -EPERM;
1232	}
1233
1234	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1235								P9_OREAD);
1236	if (IS_ERR(fid))
1237		return PTR_ERR(fid);
1238
1239	v9fs_invalidate_inode_attr(dir);
1240	p9_fid_put(fid);
1241	return 0;
1242}
1243
1244/**
1245 * v9fs_vfs_symlink - helper function to create symlinks
1246 * @idmap: idmap of the mount
1247 * @dir: directory inode containing symlink
1248 * @dentry: dentry for symlink
1249 * @symname: symlink data
1250 *
1251 * See Also: 9P2000.u RFC for more information
1252 *
1253 */
1254
1255static int
1256v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
1257		 struct dentry *dentry, const char *symname)
1258{
1259	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1260		 dir->i_ino, dentry, symname);
1261
1262	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1263}
1264
1265#define U32_MAX_DIGITS 10
1266
1267/**
1268 * v9fs_vfs_link - create a hardlink
1269 * @old_dentry: dentry for file to link to
1270 * @dir: inode destination for new link
1271 * @dentry: dentry for link
1272 *
1273 */
1274
1275static int
1276v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1277	      struct dentry *dentry)
1278{
1279	int retval;
1280	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1281	struct p9_fid *oldfid;
1282
1283	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1284		 dir->i_ino, dentry, old_dentry);
1285
1286	oldfid = v9fs_fid_clone(old_dentry);
1287	if (IS_ERR(oldfid))
1288		return PTR_ERR(oldfid);
1289
1290	sprintf(name, "%d\n", oldfid->fid);
1291	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1292	if (!retval) {
1293		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1294		v9fs_invalidate_inode_attr(dir);
1295	}
1296	p9_fid_put(oldfid);
1297	return retval;
1298}
1299
1300/**
1301 * v9fs_vfs_mknod - create a special file
1302 * @idmap: idmap of the mount
1303 * @dir: inode destination for new link
1304 * @dentry: dentry for file
1305 * @mode: mode for creation
1306 * @rdev: device associated with special file
1307 *
1308 */
1309
1310static int
1311v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1312	       struct dentry *dentry, umode_t mode, dev_t rdev)
1313{
1314	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1315	int retval;
1316	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1317	u32 perm;
1318
1319	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1320		 dir->i_ino, dentry, mode,
1321		 MAJOR(rdev), MINOR(rdev));
1322
1323	/* build extension */
1324	if (S_ISBLK(mode))
1325		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1326	else if (S_ISCHR(mode))
1327		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1328	else
1329		*name = 0;
1330
1331	perm = unixmode2p9mode(v9ses, mode);
1332	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1333
1334	return retval;
1335}
1336
1337int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1338{
1339	int umode;
1340	dev_t rdev;
1341	struct p9_wstat *st;
1342	struct v9fs_session_info *v9ses;
1343	unsigned int flags;
1344
1345	v9ses = v9fs_inode2v9ses(inode);
1346	st = p9_client_stat(fid);
1347	if (IS_ERR(st))
1348		return PTR_ERR(st);
1349	/*
1350	 * Don't update inode if the file type is different
1351	 */
1352	umode = p9mode2unixmode(v9ses, st, &rdev);
1353	if (inode_wrong_type(inode, umode))
1354		goto out;
1355
1356	/*
1357	 * We don't want to refresh inode->i_size,
1358	 * because we may have cached data
1359	 */
1360	flags = (v9ses->cache & CACHE_LOOSE) ?
1361		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1362	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1363out:
1364	p9stat_free(st);
1365	kfree(st);
1366	return 0;
1367}
1368
1369static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1370	.create = v9fs_vfs_create,
1371	.lookup = v9fs_vfs_lookup,
1372	.atomic_open = v9fs_vfs_atomic_open,
1373	.symlink = v9fs_vfs_symlink,
1374	.link = v9fs_vfs_link,
1375	.unlink = v9fs_vfs_unlink,
1376	.mkdir = v9fs_vfs_mkdir,
1377	.rmdir = v9fs_vfs_rmdir,
1378	.mknod = v9fs_vfs_mknod,
1379	.rename = v9fs_vfs_rename,
1380	.getattr = v9fs_vfs_getattr,
1381	.setattr = v9fs_vfs_setattr,
1382};
1383
1384static const struct inode_operations v9fs_dir_inode_operations = {
1385	.create = v9fs_vfs_create,
1386	.lookup = v9fs_vfs_lookup,
1387	.atomic_open = v9fs_vfs_atomic_open,
1388	.unlink = v9fs_vfs_unlink,
1389	.mkdir = v9fs_vfs_mkdir,
1390	.rmdir = v9fs_vfs_rmdir,
1391	.mknod = v9fs_vfs_mknod,
1392	.rename = v9fs_vfs_rename,
1393	.getattr = v9fs_vfs_getattr,
1394	.setattr = v9fs_vfs_setattr,
1395};
1396
1397static const struct inode_operations v9fs_file_inode_operations = {
1398	.getattr = v9fs_vfs_getattr,
1399	.setattr = v9fs_vfs_setattr,
1400};
1401
1402static const struct inode_operations v9fs_symlink_inode_operations = {
1403	.get_link = v9fs_vfs_get_link,
1404	.getattr = v9fs_vfs_getattr,
1405	.setattr = v9fs_vfs_setattr,
1406};
1407
v6.8
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file contains vfs inode ops for the 9P2000 protocol.
   4 *
   5 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   6 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/module.h>
  12#include <linux/errno.h>
  13#include <linux/fs.h>
  14#include <linux/file.h>
  15#include <linux/pagemap.h>
  16#include <linux/stat.h>
  17#include <linux/string.h>
  18#include <linux/namei.h>
  19#include <linux/sched.h>
  20#include <linux/slab.h>
  21#include <linux/xattr.h>
  22#include <linux/posix_acl.h>
  23#include <net/9p/9p.h>
  24#include <net/9p/client.h>
  25
  26#include "v9fs.h"
  27#include "v9fs_vfs.h"
  28#include "fid.h"
  29#include "cache.h"
  30#include "xattr.h"
  31#include "acl.h"
  32
  33static const struct inode_operations v9fs_dir_inode_operations;
  34static const struct inode_operations v9fs_dir_inode_operations_dotu;
  35static const struct inode_operations v9fs_file_inode_operations;
  36static const struct inode_operations v9fs_symlink_inode_operations;
  37
  38/**
  39 * unixmode2p9mode - convert unix mode bits to plan 9
  40 * @v9ses: v9fs session information
  41 * @mode: mode to convert
  42 *
  43 */
  44
  45static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  46{
  47	int res;
  48
  49	res = mode & 0777;
  50	if (S_ISDIR(mode))
  51		res |= P9_DMDIR;
  52	if (v9fs_proto_dotu(v9ses)) {
  53		if (v9ses->nodev == 0) {
  54			if (S_ISSOCK(mode))
  55				res |= P9_DMSOCKET;
  56			if (S_ISFIFO(mode))
  57				res |= P9_DMNAMEDPIPE;
  58			if (S_ISBLK(mode))
  59				res |= P9_DMDEVICE;
  60			if (S_ISCHR(mode))
  61				res |= P9_DMDEVICE;
  62		}
  63
  64		if ((mode & S_ISUID) == S_ISUID)
  65			res |= P9_DMSETUID;
  66		if ((mode & S_ISGID) == S_ISGID)
  67			res |= P9_DMSETGID;
  68		if ((mode & S_ISVTX) == S_ISVTX)
  69			res |= P9_DMSETVTX;
  70	}
  71	return res;
  72}
  73
  74/**
  75 * p9mode2perm- convert plan9 mode bits to unix permission bits
  76 * @v9ses: v9fs session information
  77 * @stat: p9_wstat from which mode need to be derived
  78 *
  79 */
  80static int p9mode2perm(struct v9fs_session_info *v9ses,
  81		       struct p9_wstat *stat)
  82{
  83	int res;
  84	int mode = stat->mode;
  85
  86	res = mode & S_IALLUGO;
  87	if (v9fs_proto_dotu(v9ses)) {
  88		if ((mode & P9_DMSETUID) == P9_DMSETUID)
  89			res |= S_ISUID;
  90
  91		if ((mode & P9_DMSETGID) == P9_DMSETGID)
  92			res |= S_ISGID;
  93
  94		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
  95			res |= S_ISVTX;
  96	}
  97	return res;
  98}
  99
 100/**
 101 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 102 * @v9ses: v9fs session information
 103 * @stat: p9_wstat from which mode need to be derived
 104 * @rdev: major number, minor number in case of device files.
 105 *
 106 */
 107static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 108			       struct p9_wstat *stat, dev_t *rdev)
 109{
 110	int res, r;
 111	u32 mode = stat->mode;
 112
 113	*rdev = 0;
 114	res = p9mode2perm(v9ses, stat);
 115
 116	if ((mode & P9_DMDIR) == P9_DMDIR)
 117		res |= S_IFDIR;
 118	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 119		res |= S_IFLNK;
 120	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 121		 && (v9ses->nodev == 0))
 122		res |= S_IFSOCK;
 123	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 124		 && (v9ses->nodev == 0))
 125		res |= S_IFIFO;
 126	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 127		 && (v9ses->nodev == 0)) {
 128		char type = 0;
 129		int major = -1, minor = -1;
 130
 131		r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
 132		if (r != 3) {
 133			p9_debug(P9_DEBUG_ERROR,
 134				 "invalid device string, umode will be bogus: %s\n",
 135				 stat->extension);
 136			return res;
 137		}
 138		switch (type) {
 139		case 'c':
 140			res |= S_IFCHR;
 141			break;
 142		case 'b':
 143			res |= S_IFBLK;
 144			break;
 145		default:
 146			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 147				 type, stat->extension);
 148		}
 149		*rdev = MKDEV(major, minor);
 150	} else
 151		res |= S_IFREG;
 152
 153	return res;
 154}
 155
 156/**
 157 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 158 * @uflags: flags to convert
 159 * @extended: if .u extensions are active
 160 */
 161
 162int v9fs_uflags2omode(int uflags, int extended)
 163{
 164	int ret;
 165
 166	switch (uflags&3) {
 167	default:
 168	case O_RDONLY:
 169		ret = P9_OREAD;
 170		break;
 171
 172	case O_WRONLY:
 173		ret = P9_OWRITE;
 174		break;
 175
 176	case O_RDWR:
 177		ret = P9_ORDWR;
 178		break;
 179	}
 180
 
 
 
 181	if (extended) {
 182		if (uflags & O_EXCL)
 183			ret |= P9_OEXCL;
 184
 185		if (uflags & O_APPEND)
 186			ret |= P9_OAPPEND;
 187	}
 188
 189	return ret;
 190}
 191
 192/**
 193 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 194 * @wstat: structure to initialize
 195 *
 196 */
 197
 198void
 199v9fs_blank_wstat(struct p9_wstat *wstat)
 200{
 201	wstat->type = ~0;
 202	wstat->dev = ~0;
 203	wstat->qid.type = ~0;
 204	wstat->qid.version = ~0;
 205	*((long long *)&wstat->qid.path) = ~0;
 206	wstat->mode = ~0;
 207	wstat->atime = ~0;
 208	wstat->mtime = ~0;
 209	wstat->length = ~0;
 210	wstat->name = NULL;
 211	wstat->uid = NULL;
 212	wstat->gid = NULL;
 213	wstat->muid = NULL;
 214	wstat->n_uid = INVALID_UID;
 215	wstat->n_gid = INVALID_GID;
 216	wstat->n_muid = INVALID_UID;
 217	wstat->extension = NULL;
 218}
 219
 220/**
 221 * v9fs_alloc_inode - helper function to allocate an inode
 222 * @sb: The superblock to allocate the inode from
 223 */
 224struct inode *v9fs_alloc_inode(struct super_block *sb)
 225{
 226	struct v9fs_inode *v9inode;
 227
 228	v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
 229	if (!v9inode)
 230		return NULL;
 231	v9inode->cache_validity = 0;
 232	mutex_init(&v9inode->v_mutex);
 233	return &v9inode->netfs.inode;
 234}
 235
 236/**
 237 * v9fs_free_inode - destroy an inode
 238 * @inode: The inode to be freed
 239 */
 240
 241void v9fs_free_inode(struct inode *inode)
 242{
 243	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 244}
 245
 246/*
 247 * Set parameters for the netfs library
 248 */
 249void v9fs_set_netfs_context(struct inode *inode)
 250{
 251	struct v9fs_inode *v9inode = V9FS_I(inode);
 252	netfs_inode_init(&v9inode->netfs, &v9fs_req_ops, true);
 253}
 254
 255int v9fs_init_inode(struct v9fs_session_info *v9ses,
 256		    struct inode *inode, umode_t mode, dev_t rdev)
 257{
 258	int err = 0;
 259
 260	inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
 261	inode->i_blocks = 0;
 262	inode->i_rdev = rdev;
 263	simple_inode_init_ts(inode);
 264	inode->i_mapping->a_ops = &v9fs_addr_operations;
 265	inode->i_private = NULL;
 266
 267	switch (mode & S_IFMT) {
 268	case S_IFIFO:
 269	case S_IFBLK:
 270	case S_IFCHR:
 271	case S_IFSOCK:
 272		if (v9fs_proto_dotl(v9ses)) {
 273			inode->i_op = &v9fs_file_inode_operations_dotl;
 274		} else if (v9fs_proto_dotu(v9ses)) {
 275			inode->i_op = &v9fs_file_inode_operations;
 276		} else {
 277			p9_debug(P9_DEBUG_ERROR,
 278				 "special files without extended mode\n");
 279			err = -EINVAL;
 280			goto error;
 281		}
 282		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 283		break;
 284	case S_IFREG:
 285		if (v9fs_proto_dotl(v9ses)) {
 286			inode->i_op = &v9fs_file_inode_operations_dotl;
 287			inode->i_fop = &v9fs_file_operations_dotl;
 288		} else {
 289			inode->i_op = &v9fs_file_inode_operations;
 290			inode->i_fop = &v9fs_file_operations;
 291		}
 292
 293		break;
 294	case S_IFLNK:
 295		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 296			p9_debug(P9_DEBUG_ERROR,
 297				 "extended modes used with legacy protocol\n");
 298			err = -EINVAL;
 299			goto error;
 300		}
 301
 302		if (v9fs_proto_dotl(v9ses))
 303			inode->i_op = &v9fs_symlink_inode_operations_dotl;
 304		else
 305			inode->i_op = &v9fs_symlink_inode_operations;
 306
 307		break;
 308	case S_IFDIR:
 309		inc_nlink(inode);
 310		if (v9fs_proto_dotl(v9ses))
 311			inode->i_op = &v9fs_dir_inode_operations_dotl;
 312		else if (v9fs_proto_dotu(v9ses))
 313			inode->i_op = &v9fs_dir_inode_operations_dotu;
 314		else
 315			inode->i_op = &v9fs_dir_inode_operations;
 316
 317		if (v9fs_proto_dotl(v9ses))
 318			inode->i_fop = &v9fs_dir_operations_dotl;
 319		else
 320			inode->i_fop = &v9fs_dir_operations;
 321
 322		break;
 323	default:
 324		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 325			 mode, mode & S_IFMT);
 326		err = -EINVAL;
 327		goto error;
 328	}
 329error:
 330	return err;
 331
 332}
 333
 334/**
 335 * v9fs_get_inode - helper function to setup an inode
 336 * @sb: superblock
 337 * @mode: mode to setup inode with
 338 * @rdev: The device numbers to set
 339 */
 340
 341struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 342{
 343	int err;
 344	struct inode *inode;
 345	struct v9fs_session_info *v9ses = sb->s_fs_info;
 346
 347	p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
 348
 349	inode = new_inode(sb);
 350	if (!inode) {
 351		pr_warn("%s (%d): Problem allocating inode\n",
 352			__func__, task_pid_nr(current));
 353		return ERR_PTR(-ENOMEM);
 354	}
 355	err = v9fs_init_inode(v9ses, inode, mode, rdev);
 356	if (err) {
 357		iput(inode);
 358		return ERR_PTR(err);
 359	}
 360	v9fs_set_netfs_context(inode);
 361	return inode;
 362}
 363
 364/**
 365 * v9fs_evict_inode - Remove an inode from the inode cache
 366 * @inode: inode to release
 367 *
 368 */
 369void v9fs_evict_inode(struct inode *inode)
 370{
 371	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
 372	__le32 __maybe_unused version;
 373
 374	truncate_inode_pages_final(&inode->i_data);
 
 
 375
 376	version = cpu_to_le32(v9inode->qid.version);
 377	netfs_clear_inode_writeback(inode, &version);
 378
 379	clear_inode(inode);
 380	filemap_fdatawrite(&inode->i_data);
 381
 382#ifdef CONFIG_9P_FSCACHE
 383	fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
 
 384#endif
 
 
 385}
 386
 387static int v9fs_test_inode(struct inode *inode, void *data)
 388{
 389	int umode;
 390	dev_t rdev;
 391	struct v9fs_inode *v9inode = V9FS_I(inode);
 392	struct p9_wstat *st = (struct p9_wstat *)data;
 393	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 394
 395	umode = p9mode2unixmode(v9ses, st, &rdev);
 396	/* don't match inode of different type */
 397	if (inode_wrong_type(inode, umode))
 398		return 0;
 399
 400	/* compare qid details */
 401	if (memcmp(&v9inode->qid.version,
 402		   &st->qid.version, sizeof(v9inode->qid.version)))
 403		return 0;
 404
 405	if (v9inode->qid.type != st->qid.type)
 406		return 0;
 407
 408	if (v9inode->qid.path != st->qid.path)
 409		return 0;
 410	return 1;
 411}
 412
 413static int v9fs_test_new_inode(struct inode *inode, void *data)
 414{
 415	return 0;
 416}
 417
 418static int v9fs_set_inode(struct inode *inode,  void *data)
 419{
 420	struct v9fs_inode *v9inode = V9FS_I(inode);
 421	struct p9_wstat *st = (struct p9_wstat *)data;
 422
 423	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 424	return 0;
 425}
 426
 427static struct inode *v9fs_qid_iget(struct super_block *sb,
 428				   struct p9_qid *qid,
 429				   struct p9_wstat *st,
 430				   int new)
 431{
 432	dev_t rdev;
 433	int retval;
 434	umode_t umode;
 435	unsigned long i_ino;
 436	struct inode *inode;
 437	struct v9fs_session_info *v9ses = sb->s_fs_info;
 438	int (*test)(struct inode *inode, void *data);
 439
 440	if (new)
 441		test = v9fs_test_new_inode;
 442	else
 443		test = v9fs_test_inode;
 444
 445	i_ino = v9fs_qid2ino(qid);
 446	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 447	if (!inode)
 448		return ERR_PTR(-ENOMEM);
 449	if (!(inode->i_state & I_NEW))
 450		return inode;
 451	/*
 452	 * initialize the inode with the stat info
 453	 * FIXME!! we may need support for stale inodes
 454	 * later.
 455	 */
 456	inode->i_ino = i_ino;
 457	umode = p9mode2unixmode(v9ses, st, &rdev);
 458	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 459	if (retval)
 460		goto error;
 461
 462	v9fs_stat2inode(st, inode, sb, 0);
 463	v9fs_set_netfs_context(inode);
 464	v9fs_cache_inode_get_cookie(inode);
 465	unlock_new_inode(inode);
 466	return inode;
 467error:
 468	iget_failed(inode);
 469	return ERR_PTR(retval);
 470
 471}
 472
 473struct inode *
 474v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 475		    struct super_block *sb, int new)
 476{
 477	struct p9_wstat *st;
 478	struct inode *inode = NULL;
 479
 480	st = p9_client_stat(fid);
 481	if (IS_ERR(st))
 482		return ERR_CAST(st);
 483
 484	inode = v9fs_qid_iget(sb, &st->qid, st, new);
 485	p9stat_free(st);
 486	kfree(st);
 487	return inode;
 488}
 489
 490/**
 491 * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 492 * plan 9 AT flag.
 493 * @flags: flags to convert
 494 */
 495static int v9fs_at_to_dotl_flags(int flags)
 496{
 497	int rflags = 0;
 498
 499	if (flags & AT_REMOVEDIR)
 500		rflags |= P9_DOTL_AT_REMOVEDIR;
 501
 502	return rflags;
 503}
 504
 505/**
 506 * v9fs_dec_count - helper functon to drop i_nlink.
 507 *
 508 * If a directory had nlink <= 2 (including . and ..), then we should not drop
 509 * the link count, which indicates the underlying exported fs doesn't maintain
 510 * nlink accurately. e.g.
 511 * - overlayfs sets nlink to 1 for merged dir
 512 * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
 513 *   than EXT4_LINK_MAX (65000) links.
 514 *
 515 * @inode: inode whose nlink is being dropped
 516 */
 517static void v9fs_dec_count(struct inode *inode)
 518{
 519	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
 520		drop_nlink(inode);
 521}
 522
 523/**
 524 * v9fs_remove - helper function to remove files and directories
 525 * @dir: directory inode that is being deleted
 526 * @dentry:  dentry that is being deleted
 527 * @flags: removing a directory
 528 *
 529 */
 530
 531static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 532{
 533	struct inode *inode;
 534	int retval = -EOPNOTSUPP;
 535	struct p9_fid *v9fid, *dfid;
 536	struct v9fs_session_info *v9ses;
 537
 538	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 539		 dir, dentry, flags);
 540
 541	v9ses = v9fs_inode2v9ses(dir);
 542	inode = d_inode(dentry);
 543	dfid = v9fs_parent_fid(dentry);
 544	if (IS_ERR(dfid)) {
 545		retval = PTR_ERR(dfid);
 546		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 547		return retval;
 548	}
 549	if (v9fs_proto_dotl(v9ses))
 550		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 551					    v9fs_at_to_dotl_flags(flags));
 552	p9_fid_put(dfid);
 553	if (retval == -EOPNOTSUPP) {
 554		/* Try the one based on path */
 555		v9fid = v9fs_fid_clone(dentry);
 556		if (IS_ERR(v9fid))
 557			return PTR_ERR(v9fid);
 558		retval = p9_client_remove(v9fid);
 559	}
 560	if (!retval) {
 561		/*
 562		 * directories on unlink should have zero
 563		 * link count
 564		 */
 565		if (flags & AT_REMOVEDIR) {
 566			clear_nlink(inode);
 567			v9fs_dec_count(dir);
 568		} else
 569			v9fs_dec_count(inode);
 570
 571		v9fs_invalidate_inode_attr(inode);
 572		v9fs_invalidate_inode_attr(dir);
 573
 574		/* invalidate all fids associated with dentry */
 575		/* NOTE: This will not include open fids */
 576		dentry->d_op->d_release(dentry);
 577	}
 578	return retval;
 579}
 580
 581/**
 582 * v9fs_create - Create a file
 583 * @v9ses: session information
 584 * @dir: directory that dentry is being created in
 585 * @dentry:  dentry that is being created
 586 * @extension: 9p2000.u extension string to support devices, etc.
 587 * @perm: create permissions
 588 * @mode: open mode
 589 *
 590 */
 591static struct p9_fid *
 592v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 593		struct dentry *dentry, char *extension, u32 perm, u8 mode)
 594{
 595	int err;
 596	const unsigned char *name;
 597	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
 598	struct inode *inode;
 599
 600	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 601
 602	name = dentry->d_name.name;
 603	dfid = v9fs_parent_fid(dentry);
 604	if (IS_ERR(dfid)) {
 605		err = PTR_ERR(dfid);
 606		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 607		return ERR_PTR(err);
 608	}
 609
 610	/* clone a fid to use for creation */
 611	ofid = clone_fid(dfid);
 612	if (IS_ERR(ofid)) {
 613		err = PTR_ERR(ofid);
 614		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 615		goto error;
 616	}
 617
 618	err = p9_client_fcreate(ofid, name, perm, mode, extension);
 619	if (err < 0) {
 620		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 621		goto error;
 622	}
 623
 624	if (!(perm & P9_DMLINK)) {
 625		/* now walk from the parent so we can get unopened fid */
 626		fid = p9_client_walk(dfid, 1, &name, 1);
 627		if (IS_ERR(fid)) {
 628			err = PTR_ERR(fid);
 629			p9_debug(P9_DEBUG_VFS,
 630				   "p9_client_walk failed %d\n", err);
 631			goto error;
 632		}
 633		/*
 634		 * instantiate inode and assign the unopened fid to the dentry
 635		 */
 636		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 637		if (IS_ERR(inode)) {
 638			err = PTR_ERR(inode);
 639			p9_debug(P9_DEBUG_VFS,
 640				   "inode creation failed %d\n", err);
 641			goto error;
 642		}
 643		v9fs_fid_add(dentry, &fid);
 644		d_instantiate(dentry, inode);
 645	}
 646	p9_fid_put(dfid);
 647	return ofid;
 648error:
 649	p9_fid_put(dfid);
 650	p9_fid_put(ofid);
 651	p9_fid_put(fid);
 652	return ERR_PTR(err);
 653}
 654
 655/**
 656 * v9fs_vfs_create - VFS hook to create a regular file
 657 * @idmap: idmap of the mount
 658 * @dir: The parent directory
 659 * @dentry: The name of file to be created
 660 * @mode: The UNIX file mode to set
 661 * @excl: True if the file must not yet exist
 662 *
 663 * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 664 * for mknod(2).
 665 *
 666 */
 667
 668static int
 669v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
 670		struct dentry *dentry, umode_t mode, bool excl)
 671{
 672	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 673	u32 perm = unixmode2p9mode(v9ses, mode);
 674	struct p9_fid *fid;
 675
 676	/* P9_OEXCL? */
 677	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 678	if (IS_ERR(fid))
 679		return PTR_ERR(fid);
 680
 681	v9fs_invalidate_inode_attr(dir);
 682	p9_fid_put(fid);
 683
 684	return 0;
 685}
 686
 687/**
 688 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 689 * @idmap: idmap of the mount
 690 * @dir:  inode that is being unlinked
 691 * @dentry: dentry that is being unlinked
 692 * @mode: mode for new directory
 693 *
 694 */
 695
 696static int v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 697			  struct dentry *dentry, umode_t mode)
 698{
 699	int err;
 700	u32 perm;
 701	struct p9_fid *fid;
 702	struct v9fs_session_info *v9ses;
 703
 704	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 705	err = 0;
 706	v9ses = v9fs_inode2v9ses(dir);
 707	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 708	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 709	if (IS_ERR(fid)) {
 710		err = PTR_ERR(fid);
 711		fid = NULL;
 712	} else {
 713		inc_nlink(dir);
 714		v9fs_invalidate_inode_attr(dir);
 715	}
 716
 717	if (fid)
 718		p9_fid_put(fid);
 719
 720	return err;
 721}
 722
 723/**
 724 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 725 * @dir:  inode that is being walked from
 726 * @dentry: dentry that is being walked to?
 727 * @flags: lookup flags (unused)
 728 *
 729 */
 730
 731struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 732				      unsigned int flags)
 733{
 734	struct dentry *res;
 735	struct v9fs_session_info *v9ses;
 736	struct p9_fid *dfid, *fid;
 737	struct inode *inode;
 738	const unsigned char *name;
 739
 740	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 741		 dir, dentry, dentry, flags);
 742
 743	if (dentry->d_name.len > NAME_MAX)
 744		return ERR_PTR(-ENAMETOOLONG);
 745
 746	v9ses = v9fs_inode2v9ses(dir);
 747	/* We can walk d_parent because we hold the dir->i_mutex */
 748	dfid = v9fs_parent_fid(dentry);
 749	if (IS_ERR(dfid))
 750		return ERR_CAST(dfid);
 751
 752	/*
 753	 * Make sure we don't use a wrong inode due to parallel
 754	 * unlink. For cached mode create calls request for new
 755	 * inode. But with cache disabled, lookup should do this.
 756	 */
 757	name = dentry->d_name.name;
 758	fid = p9_client_walk(dfid, 1, &name, 1);
 759	p9_fid_put(dfid);
 760	if (fid == ERR_PTR(-ENOENT))
 761		inode = NULL;
 762	else if (IS_ERR(fid))
 763		inode = ERR_CAST(fid);
 764	else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 765		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 766	else
 767		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 768	/*
 769	 * If we had a rename on the server and a parallel lookup
 770	 * for the new name, then make sure we instantiate with
 771	 * the new name. ie look up for a/b, while on server somebody
 772	 * moved b under k and client parallely did a lookup for
 773	 * k/b.
 774	 */
 775	res = d_splice_alias(inode, dentry);
 776	if (!IS_ERR(fid)) {
 777		if (!res)
 778			v9fs_fid_add(dentry, &fid);
 779		else if (!IS_ERR(res))
 780			v9fs_fid_add(res, &fid);
 781		else
 782			p9_fid_put(fid);
 783	}
 784	return res;
 785}
 786
 787static int
 788v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 789		     struct file *file, unsigned int flags, umode_t mode)
 790{
 791	int err;
 792	u32 perm;
 793	struct v9fs_inode __maybe_unused *v9inode;
 794	struct v9fs_session_info *v9ses;
 795	struct p9_fid *fid;
 796	struct dentry *res = NULL;
 797	struct inode *inode;
 798	int p9_omode;
 799
 800	if (d_in_lookup(dentry)) {
 801		res = v9fs_vfs_lookup(dir, dentry, 0);
 802		if (IS_ERR(res))
 803			return PTR_ERR(res);
 804
 805		if (res)
 806			dentry = res;
 807	}
 808
 809	/* Only creates */
 810	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 811		return finish_no_open(file, res);
 812
 813	v9ses = v9fs_inode2v9ses(dir);
 814	perm = unixmode2p9mode(v9ses, mode);
 815	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
 816
 817	if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
 818		p9_omode = (p9_omode & ~P9_OWRITE) | P9_ORDWR;
 819		p9_debug(P9_DEBUG_CACHE,
 820			"write-only file with writeback enabled, creating w/ O_RDWR\n");
 821	}
 822	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
 823	if (IS_ERR(fid)) {
 824		err = PTR_ERR(fid);
 825		goto error;
 826	}
 827
 828	v9fs_invalidate_inode_attr(dir);
 829	inode = d_inode(dentry);
 830	v9inode = V9FS_I(inode);
 831	err = finish_open(file, dentry, generic_file_open);
 832	if (err)
 833		goto error;
 834
 835	file->private_data = fid;
 836#ifdef CONFIG_9P_FSCACHE
 837	if (v9ses->cache & CACHE_FSCACHE)
 838		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 839				   file->f_mode & FMODE_WRITE);
 840#endif
 841
 842	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
 843	v9fs_open_fid_add(inode, &fid);
 844
 845	file->f_mode |= FMODE_CREATED;
 846out:
 847	dput(res);
 848	return err;
 849
 850error:
 851	p9_fid_put(fid);
 852	goto out;
 853}
 854
 855/**
 856 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 857 * @i:  inode that is being unlinked
 858 * @d: dentry that is being unlinked
 859 *
 860 */
 861
 862int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 863{
 864	return v9fs_remove(i, d, 0);
 865}
 866
 867/**
 868 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 869 * @i:  inode that is being unlinked
 870 * @d: dentry that is being unlinked
 871 *
 872 */
 873
 874int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 875{
 876	return v9fs_remove(i, d, AT_REMOVEDIR);
 877}
 878
 879/**
 880 * v9fs_vfs_rename - VFS hook to rename an inode
 881 * @idmap: The idmap of the mount
 882 * @old_dir:  old dir inode
 883 * @old_dentry: old dentry
 884 * @new_dir: new dir inode
 885 * @new_dentry: new dentry
 886 * @flags: RENAME_* flags
 887 *
 888 */
 889
 890int
 891v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 892		struct dentry *old_dentry, struct inode *new_dir,
 893		struct dentry *new_dentry, unsigned int flags)
 894{
 895	int retval;
 896	struct inode *old_inode;
 897	struct inode *new_inode;
 898	struct v9fs_session_info *v9ses;
 899	struct p9_fid *oldfid = NULL, *dfid = NULL;
 900	struct p9_fid *olddirfid = NULL;
 901	struct p9_fid *newdirfid = NULL;
 902	struct p9_wstat wstat;
 903
 904	if (flags)
 905		return -EINVAL;
 906
 907	p9_debug(P9_DEBUG_VFS, "\n");
 908	old_inode = d_inode(old_dentry);
 909	new_inode = d_inode(new_dentry);
 910	v9ses = v9fs_inode2v9ses(old_inode);
 911	oldfid = v9fs_fid_lookup(old_dentry);
 912	if (IS_ERR(oldfid))
 913		return PTR_ERR(oldfid);
 914
 915	dfid = v9fs_parent_fid(old_dentry);
 916	olddirfid = clone_fid(dfid);
 917	p9_fid_put(dfid);
 918	dfid = NULL;
 919
 920	if (IS_ERR(olddirfid)) {
 921		retval = PTR_ERR(olddirfid);
 922		goto error;
 923	}
 924
 925	dfid = v9fs_parent_fid(new_dentry);
 926	newdirfid = clone_fid(dfid);
 927	p9_fid_put(dfid);
 928	dfid = NULL;
 929
 930	if (IS_ERR(newdirfid)) {
 931		retval = PTR_ERR(newdirfid);
 932		goto error;
 933	}
 934
 935	down_write(&v9ses->rename_sem);
 936	if (v9fs_proto_dotl(v9ses)) {
 937		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 938					    newdirfid, new_dentry->d_name.name);
 939		if (retval == -EOPNOTSUPP)
 940			retval = p9_client_rename(oldfid, newdirfid,
 941						  new_dentry->d_name.name);
 942		if (retval != -EOPNOTSUPP)
 943			goto error_locked;
 944	}
 945	if (old_dentry->d_parent != new_dentry->d_parent) {
 946		/*
 947		 * 9P .u can only handle file rename in the same directory
 948		 */
 949
 950		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
 951		retval = -EXDEV;
 952		goto error_locked;
 953	}
 954	v9fs_blank_wstat(&wstat);
 955	wstat.muid = v9ses->uname;
 956	wstat.name = new_dentry->d_name.name;
 957	retval = p9_client_wstat(oldfid, &wstat);
 958
 959error_locked:
 960	if (!retval) {
 961		if (new_inode) {
 962			if (S_ISDIR(new_inode->i_mode))
 963				clear_nlink(new_inode);
 964			else
 965				v9fs_dec_count(new_inode);
 966		}
 967		if (S_ISDIR(old_inode->i_mode)) {
 968			if (!new_inode)
 969				inc_nlink(new_dir);
 970			v9fs_dec_count(old_dir);
 971		}
 972		v9fs_invalidate_inode_attr(old_inode);
 973		v9fs_invalidate_inode_attr(old_dir);
 974		v9fs_invalidate_inode_attr(new_dir);
 975
 976		/* successful rename */
 977		d_move(old_dentry, new_dentry);
 978	}
 979	up_write(&v9ses->rename_sem);
 980
 981error:
 982	p9_fid_put(newdirfid);
 983	p9_fid_put(olddirfid);
 984	p9_fid_put(oldfid);
 985	return retval;
 986}
 987
 988/**
 989 * v9fs_vfs_getattr - retrieve file metadata
 990 * @idmap: idmap of the mount
 991 * @path: Object to query
 992 * @stat: metadata structure to populate
 993 * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
 994 * @flags: AT_STATX_xxx setting
 995 *
 996 */
 997
 998static int
 999v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
1000		 struct kstat *stat, u32 request_mask, unsigned int flags)
1001{
1002	struct dentry *dentry = path->dentry;
1003	struct inode *inode = d_inode(dentry);
1004	struct v9fs_session_info *v9ses;
1005	struct p9_fid *fid;
1006	struct p9_wstat *st;
1007
1008	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1009	v9ses = v9fs_dentry2v9ses(dentry);
1010	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
1011		generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1012		return 0;
1013	} else if (v9ses->cache & CACHE_WRITEBACK) {
1014		if (S_ISREG(inode->i_mode)) {
1015			int retval = filemap_fdatawrite(inode->i_mapping);
1016
1017			if (retval)
1018				p9_debug(P9_DEBUG_ERROR,
1019				    "flushing writeback during getattr returned %d\n", retval);
1020		}
1021	}
1022	fid = v9fs_fid_lookup(dentry);
1023	if (IS_ERR(fid))
1024		return PTR_ERR(fid);
1025
1026	st = p9_client_stat(fid);
1027	p9_fid_put(fid);
1028	if (IS_ERR(st))
1029		return PTR_ERR(st);
1030
1031	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1032	generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
1033
1034	p9stat_free(st);
1035	kfree(st);
1036	return 0;
1037}
1038
1039/**
1040 * v9fs_vfs_setattr - set file metadata
1041 * @idmap: idmap of the mount
1042 * @dentry: file whose metadata to set
1043 * @iattr: metadata assignment structure
1044 *
1045 */
1046
1047static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
1048			    struct dentry *dentry, struct iattr *iattr)
1049{
1050	int retval, use_dentry = 0;
1051	struct inode *inode = d_inode(dentry);
1052	struct v9fs_session_info *v9ses;
1053	struct p9_fid *fid = NULL;
1054	struct p9_wstat wstat;
1055
1056	p9_debug(P9_DEBUG_VFS, "\n");
1057	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1058	if (retval)
1059		return retval;
1060
1061	v9ses = v9fs_dentry2v9ses(dentry);
1062	if (iattr->ia_valid & ATTR_FILE) {
1063		fid = iattr->ia_file->private_data;
1064		WARN_ON(!fid);
1065	}
1066	if (!fid) {
1067		fid = v9fs_fid_lookup(dentry);
1068		use_dentry = 1;
1069	}
1070	if (IS_ERR(fid))
1071		return PTR_ERR(fid);
1072
1073	v9fs_blank_wstat(&wstat);
1074	if (iattr->ia_valid & ATTR_MODE)
1075		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1076
1077	if (iattr->ia_valid & ATTR_MTIME)
1078		wstat.mtime = iattr->ia_mtime.tv_sec;
1079
1080	if (iattr->ia_valid & ATTR_ATIME)
1081		wstat.atime = iattr->ia_atime.tv_sec;
1082
1083	if (iattr->ia_valid & ATTR_SIZE)
1084		wstat.length = iattr->ia_size;
1085
1086	if (v9fs_proto_dotu(v9ses)) {
1087		if (iattr->ia_valid & ATTR_UID)
1088			wstat.n_uid = iattr->ia_uid;
1089
1090		if (iattr->ia_valid & ATTR_GID)
1091			wstat.n_gid = iattr->ia_gid;
1092	}
1093
1094	/* Write all dirty data */
1095	if (d_is_reg(dentry)) {
1096		retval = filemap_fdatawrite(inode->i_mapping);
1097		if (retval)
1098			p9_debug(P9_DEBUG_ERROR,
1099			    "flushing writeback during setattr returned %d\n", retval);
1100	}
1101
1102	retval = p9_client_wstat(fid, &wstat);
1103
1104	if (use_dentry)
1105		p9_fid_put(fid);
1106
1107	if (retval < 0)
1108		return retval;
1109
1110	if ((iattr->ia_valid & ATTR_SIZE) &&
1111		 iattr->ia_size != i_size_read(inode)) {
1112		truncate_setsize(inode, iattr->ia_size);
1113		netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
1114
1115#ifdef CONFIG_9P_FSCACHE
1116		if (v9ses->cache & CACHE_FSCACHE) {
1117			struct v9fs_inode *v9inode = V9FS_I(inode);
1118
1119			fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
1120		}
1121#endif
1122	}
1123
1124	v9fs_invalidate_inode_attr(inode);
1125
1126	setattr_copy(&nop_mnt_idmap, inode, iattr);
1127	mark_inode_dirty(inode);
1128	return 0;
1129}
1130
1131/**
1132 * v9fs_stat2inode - populate an inode structure with mistat info
1133 * @stat: Plan 9 metadata (mistat) structure
1134 * @inode: inode to populate
1135 * @sb: superblock of filesystem
1136 * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1137 *
1138 */
1139
1140void
1141v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1142		 struct super_block *sb, unsigned int flags)
1143{
1144	umode_t mode;
1145	struct v9fs_session_info *v9ses = sb->s_fs_info;
1146	struct v9fs_inode *v9inode = V9FS_I(inode);
1147
1148	set_nlink(inode, 1);
1149
1150	inode_set_atime(inode, stat->atime, 0);
1151	inode_set_mtime(inode, stat->mtime, 0);
1152	inode_set_ctime(inode, stat->mtime, 0);
1153
1154	inode->i_uid = v9ses->dfltuid;
1155	inode->i_gid = v9ses->dfltgid;
1156
1157	if (v9fs_proto_dotu(v9ses)) {
1158		inode->i_uid = stat->n_uid;
1159		inode->i_gid = stat->n_gid;
1160	}
1161	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1162		if (v9fs_proto_dotu(v9ses)) {
1163			unsigned int i_nlink;
1164			/*
1165			 * Hadlink support got added later to the .u extension.
1166			 * So there can be a server out there that doesn't
1167			 * support this even with .u extension. That would
1168			 * just leave us with stat->extension being an empty
1169			 * string, though.
1170			 */
1171			/* HARDLINKCOUNT %u */
1172			if (sscanf(stat->extension,
1173				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1174				set_nlink(inode, i_nlink);
1175		}
1176	}
1177	mode = p9mode2perm(v9ses, stat);
1178	mode |= inode->i_mode & ~S_IALLUGO;
1179	inode->i_mode = mode;
1180
1181	v9inode->netfs.remote_i_size = stat->length;
1182	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1183		v9fs_i_size_write(inode, stat->length);
1184	/* not real number of blocks, but 512 byte ones ... */
1185	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1186	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1187}
1188
1189/**
1190 * v9fs_qid2ino - convert qid into inode number
1191 * @qid: qid to hash
1192 *
1193 * BUG: potential for inode number collisions?
1194 */
1195
1196ino_t v9fs_qid2ino(struct p9_qid *qid)
1197{
1198	u64 path = qid->path + 2;
1199	ino_t i = 0;
1200
1201	if (sizeof(ino_t) == sizeof(path))
1202		memcpy(&i, &path, sizeof(ino_t));
1203	else
1204		i = (ino_t) (path ^ (path >> 32));
1205
1206	return i;
1207}
1208
1209/**
1210 * v9fs_vfs_get_link - follow a symlink path
1211 * @dentry: dentry for symlink
1212 * @inode: inode for symlink
1213 * @done: delayed call for when we are done with the return value
1214 */
1215
1216static const char *v9fs_vfs_get_link(struct dentry *dentry,
1217				     struct inode *inode,
1218				     struct delayed_call *done)
1219{
1220	struct v9fs_session_info *v9ses;
1221	struct p9_fid *fid;
1222	struct p9_wstat *st;
1223	char *res;
1224
1225	if (!dentry)
1226		return ERR_PTR(-ECHILD);
1227
1228	v9ses = v9fs_dentry2v9ses(dentry);
1229	if (!v9fs_proto_dotu(v9ses))
1230		return ERR_PTR(-EBADF);
1231
1232	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1233	fid = v9fs_fid_lookup(dentry);
1234
1235	if (IS_ERR(fid))
1236		return ERR_CAST(fid);
1237
1238	st = p9_client_stat(fid);
1239	p9_fid_put(fid);
1240	if (IS_ERR(st))
1241		return ERR_CAST(st);
1242
1243	if (!(st->mode & P9_DMSYMLINK)) {
1244		p9stat_free(st);
1245		kfree(st);
1246		return ERR_PTR(-EINVAL);
1247	}
1248	res = st->extension;
1249	st->extension = NULL;
1250	if (strlen(res) >= PATH_MAX)
1251		res[PATH_MAX - 1] = '\0';
1252
1253	p9stat_free(st);
1254	kfree(st);
1255	set_delayed_call(done, kfree_link, res);
1256	return res;
1257}
1258
1259/**
1260 * v9fs_vfs_mkspecial - create a special file
1261 * @dir: inode to create special file in
1262 * @dentry: dentry to create
1263 * @perm: mode to create special file
1264 * @extension: 9p2000.u format extension string representing special file
1265 *
1266 */
1267
1268static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1269	u32 perm, const char *extension)
1270{
1271	struct p9_fid *fid;
1272	struct v9fs_session_info *v9ses;
1273
1274	v9ses = v9fs_inode2v9ses(dir);
1275	if (!v9fs_proto_dotu(v9ses)) {
1276		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1277		return -EPERM;
1278	}
1279
1280	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1281								P9_OREAD);
1282	if (IS_ERR(fid))
1283		return PTR_ERR(fid);
1284
1285	v9fs_invalidate_inode_attr(dir);
1286	p9_fid_put(fid);
1287	return 0;
1288}
1289
1290/**
1291 * v9fs_vfs_symlink - helper function to create symlinks
1292 * @idmap: idmap of the mount
1293 * @dir: directory inode containing symlink
1294 * @dentry: dentry for symlink
1295 * @symname: symlink data
1296 *
1297 * See Also: 9P2000.u RFC for more information
1298 *
1299 */
1300
1301static int
1302v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
1303		 struct dentry *dentry, const char *symname)
1304{
1305	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1306		 dir->i_ino, dentry, symname);
1307
1308	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1309}
1310
1311#define U32_MAX_DIGITS 10
1312
1313/**
1314 * v9fs_vfs_link - create a hardlink
1315 * @old_dentry: dentry for file to link to
1316 * @dir: inode destination for new link
1317 * @dentry: dentry for link
1318 *
1319 */
1320
1321static int
1322v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1323	      struct dentry *dentry)
1324{
1325	int retval;
1326	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1327	struct p9_fid *oldfid;
1328
1329	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1330		 dir->i_ino, dentry, old_dentry);
1331
1332	oldfid = v9fs_fid_clone(old_dentry);
1333	if (IS_ERR(oldfid))
1334		return PTR_ERR(oldfid);
1335
1336	sprintf(name, "%d\n", oldfid->fid);
1337	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1338	if (!retval) {
1339		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1340		v9fs_invalidate_inode_attr(dir);
1341	}
1342	p9_fid_put(oldfid);
1343	return retval;
1344}
1345
1346/**
1347 * v9fs_vfs_mknod - create a special file
1348 * @idmap: idmap of the mount
1349 * @dir: inode destination for new link
1350 * @dentry: dentry for file
1351 * @mode: mode for creation
1352 * @rdev: device associated with special file
1353 *
1354 */
1355
1356static int
1357v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1358	       struct dentry *dentry, umode_t mode, dev_t rdev)
1359{
1360	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1361	int retval;
1362	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1363	u32 perm;
1364
1365	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1366		 dir->i_ino, dentry, mode,
1367		 MAJOR(rdev), MINOR(rdev));
1368
1369	/* build extension */
1370	if (S_ISBLK(mode))
1371		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1372	else if (S_ISCHR(mode))
1373		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1374	else
1375		*name = 0;
1376
1377	perm = unixmode2p9mode(v9ses, mode);
1378	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1379
1380	return retval;
1381}
1382
1383int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1384{
1385	int umode;
1386	dev_t rdev;
1387	struct p9_wstat *st;
1388	struct v9fs_session_info *v9ses;
1389	unsigned int flags;
1390
1391	v9ses = v9fs_inode2v9ses(inode);
1392	st = p9_client_stat(fid);
1393	if (IS_ERR(st))
1394		return PTR_ERR(st);
1395	/*
1396	 * Don't update inode if the file type is different
1397	 */
1398	umode = p9mode2unixmode(v9ses, st, &rdev);
1399	if (inode_wrong_type(inode, umode))
1400		goto out;
1401
1402	/*
1403	 * We don't want to refresh inode->i_size,
1404	 * because we may have cached data
1405	 */
1406	flags = (v9ses->cache & CACHE_LOOSE) ?
1407		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1408	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1409out:
1410	p9stat_free(st);
1411	kfree(st);
1412	return 0;
1413}
1414
1415static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1416	.create = v9fs_vfs_create,
1417	.lookup = v9fs_vfs_lookup,
1418	.atomic_open = v9fs_vfs_atomic_open,
1419	.symlink = v9fs_vfs_symlink,
1420	.link = v9fs_vfs_link,
1421	.unlink = v9fs_vfs_unlink,
1422	.mkdir = v9fs_vfs_mkdir,
1423	.rmdir = v9fs_vfs_rmdir,
1424	.mknod = v9fs_vfs_mknod,
1425	.rename = v9fs_vfs_rename,
1426	.getattr = v9fs_vfs_getattr,
1427	.setattr = v9fs_vfs_setattr,
1428};
1429
1430static const struct inode_operations v9fs_dir_inode_operations = {
1431	.create = v9fs_vfs_create,
1432	.lookup = v9fs_vfs_lookup,
1433	.atomic_open = v9fs_vfs_atomic_open,
1434	.unlink = v9fs_vfs_unlink,
1435	.mkdir = v9fs_vfs_mkdir,
1436	.rmdir = v9fs_vfs_rmdir,
1437	.mknod = v9fs_vfs_mknod,
1438	.rename = v9fs_vfs_rename,
1439	.getattr = v9fs_vfs_getattr,
1440	.setattr = v9fs_vfs_setattr,
1441};
1442
1443static const struct inode_operations v9fs_file_inode_operations = {
1444	.getattr = v9fs_vfs_getattr,
1445	.setattr = v9fs_vfs_setattr,
1446};
1447
1448static const struct inode_operations v9fs_symlink_inode_operations = {
1449	.get_link = v9fs_vfs_get_link,
1450	.getattr = v9fs_vfs_getattr,
1451	.setattr = v9fs_vfs_setattr,
1452};
1453