1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4 * All Rights Reserved.
   5 */
   6#include "xfs.h"
   7#include "xfs_fs.h"
   8#include "xfs_shared.h"
   9#include "xfs_format.h"
  10#include "xfs_log_format.h"
  11#include "xfs_trans_resv.h"
  12#include "xfs_mount.h"
  13#include "xfs_inode.h"
  14#include "xfs_trans.h"
  15#include "xfs_trans_priv.h"
  16#include "xfs_inode_item.h"
  17#include "xfs_quota.h"
  18#include "xfs_trace.h"
  19#include "xfs_icache.h"
  20#include "xfs_bmap_util.h"
  21#include "xfs_dquot_item.h"
  22#include "xfs_dquot.h"
  23#include "xfs_reflink.h"
  24#include "xfs_ialloc.h"
  25#include "xfs_ag.h"
  26#include "xfs_log_priv.h"
  27#include "xfs_health.h"
 
 
 
  28
  29#include <linux/iversion.h>
  30
  31/* Radix tree tags for incore inode tree. */
  32
  33/* inode is to be reclaimed */
  34#define XFS_ICI_RECLAIM_TAG	0
  35/* Inode has speculative preallocations (posteof or cow) to clean. */
  36#define XFS_ICI_BLOCKGC_TAG	1
  37
  38/*
  39 * The goal for walking incore inodes.  These can correspond with incore inode
  40 * radix tree tags when convenient.  Avoid existing XFS_IWALK namespace.
  41 */
  42enum xfs_icwalk_goal {
  43	/* Goals directly associated with tagged inodes. */
  44	XFS_ICWALK_BLOCKGC	= XFS_ICI_BLOCKGC_TAG,
  45	XFS_ICWALK_RECLAIM	= XFS_ICI_RECLAIM_TAG,
  46};
  47
  48static int xfs_icwalk(struct xfs_mount *mp,
  49		enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
  50static int xfs_icwalk_ag(struct xfs_perag *pag,
  51		enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
  52
  53/*
  54 * Private inode cache walk flags for struct xfs_icwalk.  Must not
  55 * coincide with XFS_ICWALK_FLAGS_VALID.
  56 */
  57
  58/* Stop scanning after icw_scan_limit inodes. */
  59#define XFS_ICWALK_FLAG_SCAN_LIMIT	(1U << 28)
  60
  61#define XFS_ICWALK_FLAG_RECLAIM_SICK	(1U << 27)
  62#define XFS_ICWALK_FLAG_UNION		(1U << 26) /* union filter algorithm */
  63
  64#define XFS_ICWALK_PRIVATE_FLAGS	(XFS_ICWALK_FLAG_SCAN_LIMIT | \
  65					 XFS_ICWALK_FLAG_RECLAIM_SICK | \
  66					 XFS_ICWALK_FLAG_UNION)
  67
 
 
 
 
 
 
 
 
 
 
 
 
  68/*
  69 * Allocate and initialise an xfs_inode.
  70 */
  71struct xfs_inode *
  72xfs_inode_alloc(
  73	struct xfs_mount	*mp,
  74	xfs_ino_t		ino)
  75{
  76	struct xfs_inode	*ip;
  77
  78	/*
  79	 * XXX: If this didn't occur in transactions, we could drop GFP_NOFAIL
  80	 * and return NULL here on ENOMEM.
  81	 */
  82	ip = alloc_inode_sb(mp->m_super, xfs_inode_cache, GFP_KERNEL | __GFP_NOFAIL);
  83
  84	if (inode_init_always(mp->m_super, VFS_I(ip))) {
  85		kmem_cache_free(xfs_inode_cache, ip);
  86		return NULL;
  87	}
  88
  89	/* VFS doesn't initialise i_mode or i_state! */
  90	VFS_I(ip)->i_mode = 0;
  91	VFS_I(ip)->i_state = 0;
  92	mapping_set_large_folios(VFS_I(ip)->i_mapping);
  93
  94	XFS_STATS_INC(mp, vn_active);
  95	ASSERT(atomic_read(&ip->i_pincount) == 0);
  96	ASSERT(ip->i_ino == 0);
  97
  98	/* initialise the xfs inode */
  99	ip->i_ino = ino;
 100	ip->i_mount = mp;
 101	memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
 102	ip->i_cowfp = NULL;
 103	memset(&ip->i_af, 0, sizeof(ip->i_af));
 104	ip->i_af.if_format = XFS_DINODE_FMT_EXTENTS;
 105	memset(&ip->i_df, 0, sizeof(ip->i_df));
 106	ip->i_flags = 0;
 107	ip->i_delayed_blks = 0;
 108	ip->i_diflags2 = mp->m_ino_geo.new_diflags2;
 109	ip->i_nblocks = 0;
 110	ip->i_forkoff = 0;
 111	ip->i_sick = 0;
 112	ip->i_checked = 0;
 113	INIT_WORK(&ip->i_ioend_work, xfs_end_io);
 114	INIT_LIST_HEAD(&ip->i_ioend_list);
 115	spin_lock_init(&ip->i_ioend_lock);
 116	ip->i_next_unlinked = NULLAGINO;
 117	ip->i_prev_unlinked = 0;
 118
 119	return ip;
 120}
 121
 122STATIC void
 123xfs_inode_free_callback(
 124	struct rcu_head		*head)
 125{
 126	struct inode		*inode = container_of(head, struct inode, i_rcu);
 127	struct xfs_inode	*ip = XFS_I(inode);
 128
 129	switch (VFS_I(ip)->i_mode & S_IFMT) {
 130	case S_IFREG:
 131	case S_IFDIR:
 132	case S_IFLNK:
 133		xfs_idestroy_fork(&ip->i_df);
 134		break;
 135	}
 136
 137	xfs_ifork_zap_attr(ip);
 138
 139	if (ip->i_cowfp) {
 140		xfs_idestroy_fork(ip->i_cowfp);
 141		kmem_cache_free(xfs_ifork_cache, ip->i_cowfp);
 142	}
 143	if (ip->i_itemp) {
 144		ASSERT(!test_bit(XFS_LI_IN_AIL,
 145				 &ip->i_itemp->ili_item.li_flags));
 146		xfs_inode_item_destroy(ip);
 147		ip->i_itemp = NULL;
 148	}
 149
 150	kmem_cache_free(xfs_inode_cache, ip);
 151}
 152
 153static void
 154__xfs_inode_free(
 155	struct xfs_inode	*ip)
 156{
 157	/* asserts to verify all state is correct here */
 158	ASSERT(atomic_read(&ip->i_pincount) == 0);
 159	ASSERT(!ip->i_itemp || list_empty(&ip->i_itemp->ili_item.li_bio_list));
 160	XFS_STATS_DEC(ip->i_mount, vn_active);
 161
 162	call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
 163}
 164
 165void
 166xfs_inode_free(
 167	struct xfs_inode	*ip)
 168{
 169	ASSERT(!xfs_iflags_test(ip, XFS_IFLUSHING));
 170
 171	/*
 172	 * Because we use RCU freeing we need to ensure the inode always
 173	 * appears to be reclaimed with an invalid inode number when in the
 174	 * free state. The ip->i_flags_lock provides the barrier against lookup
 175	 * races.
 176	 */
 177	spin_lock(&ip->i_flags_lock);
 178	ip->i_flags = XFS_IRECLAIM;
 179	ip->i_ino = 0;
 180	spin_unlock(&ip->i_flags_lock);
 181
 182	__xfs_inode_free(ip);
 183}
 184
 185/*
 186 * Queue background inode reclaim work if there are reclaimable inodes and there
 187 * isn't reclaim work already scheduled or in progress.
 188 */
 189static void
 190xfs_reclaim_work_queue(
 191	struct xfs_mount        *mp)
 192{
 193
 194	rcu_read_lock();
 195	if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
 196		queue_delayed_work(mp->m_reclaim_workqueue, &mp->m_reclaim_work,
 197			msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
 198	}
 199	rcu_read_unlock();
 200}
 201
 202/*
 203 * Background scanning to trim preallocated space. This is queued based on the
 204 * 'speculative_prealloc_lifetime' tunable (5m by default).
 205 */
 206static inline void
 207xfs_blockgc_queue(
 208	struct xfs_perag	*pag)
 209{
 210	struct xfs_mount	*mp = pag->pag_mount;
 211
 212	if (!xfs_is_blockgc_enabled(mp))
 213		return;
 214
 215	rcu_read_lock();
 216	if (radix_tree_tagged(&pag->pag_ici_root, XFS_ICI_BLOCKGC_TAG))
 217		queue_delayed_work(pag->pag_mount->m_blockgc_wq,
 218				   &pag->pag_blockgc_work,
 219				   msecs_to_jiffies(xfs_blockgc_secs * 1000));
 220	rcu_read_unlock();
 221}
 222
 223/* Set a tag on both the AG incore inode tree and the AG radix tree. */
 224static void
 225xfs_perag_set_inode_tag(
 226	struct xfs_perag	*pag,
 227	xfs_agino_t		agino,
 228	unsigned int		tag)
 229{
 230	struct xfs_mount	*mp = pag->pag_mount;
 231	bool			was_tagged;
 232
 233	lockdep_assert_held(&pag->pag_ici_lock);
 234
 235	was_tagged = radix_tree_tagged(&pag->pag_ici_root, tag);
 236	radix_tree_tag_set(&pag->pag_ici_root, agino, tag);
 237
 238	if (tag == XFS_ICI_RECLAIM_TAG)
 239		pag->pag_ici_reclaimable++;
 240
 241	if (was_tagged)
 242		return;
 243
 244	/* propagate the tag up into the perag radix tree */
 245	spin_lock(&mp->m_perag_lock);
 246	radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno, tag);
 247	spin_unlock(&mp->m_perag_lock);
 248
 249	/* start background work */
 250	switch (tag) {
 251	case XFS_ICI_RECLAIM_TAG:
 252		xfs_reclaim_work_queue(mp);
 253		break;
 254	case XFS_ICI_BLOCKGC_TAG:
 255		xfs_blockgc_queue(pag);
 256		break;
 257	}
 258
 259	trace_xfs_perag_set_inode_tag(pag, _RET_IP_);
 260}
 261
 262/* Clear a tag on both the AG incore inode tree and the AG radix tree. */
 263static void
 264xfs_perag_clear_inode_tag(
 265	struct xfs_perag	*pag,
 266	xfs_agino_t		agino,
 267	unsigned int		tag)
 268{
 269	struct xfs_mount	*mp = pag->pag_mount;
 270
 271	lockdep_assert_held(&pag->pag_ici_lock);
 272
 273	/*
 274	 * Reclaim can signal (with a null agino) that it cleared its own tag
 275	 * by removing the inode from the radix tree.
 276	 */
 277	if (agino != NULLAGINO)
 278		radix_tree_tag_clear(&pag->pag_ici_root, agino, tag);
 279	else
 280		ASSERT(tag == XFS_ICI_RECLAIM_TAG);
 281
 282	if (tag == XFS_ICI_RECLAIM_TAG)
 283		pag->pag_ici_reclaimable--;
 284
 285	if (radix_tree_tagged(&pag->pag_ici_root, tag))
 286		return;
 287
 288	/* clear the tag from the perag radix tree */
 289	spin_lock(&mp->m_perag_lock);
 290	radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno, tag);
 291	spin_unlock(&mp->m_perag_lock);
 292
 293	trace_xfs_perag_clear_inode_tag(pag, _RET_IP_);
 294}
 295
 296/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 297 * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
 298 * part of the structure. This is made more complex by the fact we store
 299 * information about the on-disk values in the VFS inode and so we can't just
 300 * overwrite the values unconditionally. Hence we save the parameters we
 301 * need to retain across reinitialisation, and rewrite them into the VFS inode
 302 * after reinitialisation even if it fails.
 303 */
 304static int
 305xfs_reinit_inode(
 306	struct xfs_mount	*mp,
 307	struct inode		*inode)
 308{
 309	int			error;
 310	uint32_t		nlink = inode->i_nlink;
 311	uint32_t		generation = inode->i_generation;
 312	uint64_t		version = inode_peek_iversion(inode);
 313	umode_t			mode = inode->i_mode;
 314	dev_t			dev = inode->i_rdev;
 315	kuid_t			uid = inode->i_uid;
 316	kgid_t			gid = inode->i_gid;
 
 317
 318	error = inode_init_always(mp->m_super, inode);
 319
 320	set_nlink(inode, nlink);
 321	inode->i_generation = generation;
 322	inode_set_iversion_queried(inode, version);
 323	inode->i_mode = mode;
 324	inode->i_rdev = dev;
 325	inode->i_uid = uid;
 326	inode->i_gid = gid;
 327	mapping_set_large_folios(inode->i_mapping);
 
 
 328	return error;
 329}
 330
 331/*
 332 * Carefully nudge an inode whose VFS state has been torn down back into a
 333 * usable state.  Drops the i_flags_lock and the rcu read lock.
 334 */
 335static int
 336xfs_iget_recycle(
 337	struct xfs_perag	*pag,
 338	struct xfs_inode	*ip) __releases(&ip->i_flags_lock)
 339{
 340	struct xfs_mount	*mp = ip->i_mount;
 341	struct inode		*inode = VFS_I(ip);
 342	int			error;
 343
 344	trace_xfs_iget_recycle(ip);
 345
 346	if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
 347		return -EAGAIN;
 348
 349	/*
 350	 * We need to make it look like the inode is being reclaimed to prevent
 351	 * the actual reclaim workers from stomping over us while we recycle
 352	 * the inode.  We can't clear the radix tree tag yet as it requires
 353	 * pag_ici_lock to be held exclusive.
 354	 */
 355	ip->i_flags |= XFS_IRECLAIM;
 356
 357	spin_unlock(&ip->i_flags_lock);
 358	rcu_read_unlock();
 359
 360	ASSERT(!rwsem_is_locked(&inode->i_rwsem));
 361	error = xfs_reinit_inode(mp, inode);
 362	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 363	if (error) {
 364		/*
 365		 * Re-initializing the inode failed, and we are in deep
 366		 * trouble.  Try to re-add it to the reclaim list.
 367		 */
 368		rcu_read_lock();
 369		spin_lock(&ip->i_flags_lock);
 370		ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
 371		ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
 372		spin_unlock(&ip->i_flags_lock);
 373		rcu_read_unlock();
 374
 375		trace_xfs_iget_recycle_fail(ip);
 376		return error;
 377	}
 378
 379	spin_lock(&pag->pag_ici_lock);
 380	spin_lock(&ip->i_flags_lock);
 381
 382	/*
 383	 * Clear the per-lifetime state in the inode as we are now effectively
 384	 * a new inode and need to return to the initial state before reuse
 385	 * occurs.
 386	 */
 387	ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
 388	ip->i_flags |= XFS_INEW;
 389	xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
 390			XFS_ICI_RECLAIM_TAG);
 391	inode->i_state = I_NEW;
 392	spin_unlock(&ip->i_flags_lock);
 393	spin_unlock(&pag->pag_ici_lock);
 394
 395	return 0;
 396}
 397
 398/*
 399 * If we are allocating a new inode, then check what was returned is
 400 * actually a free, empty inode. If we are not allocating an inode,
 401 * then check we didn't find a free inode.
 402 *
 403 * Returns:
 404 *	0		if the inode free state matches the lookup context
 405 *	-ENOENT		if the inode is free and we are not allocating
 406 *	-EFSCORRUPTED	if there is any state mismatch at all
 407 */
 408static int
 409xfs_iget_check_free_state(
 410	struct xfs_inode	*ip,
 411	int			flags)
 412{
 413	if (flags & XFS_IGET_CREATE) {
 414		/* should be a free inode */
 415		if (VFS_I(ip)->i_mode != 0) {
 416			xfs_warn(ip->i_mount,
 417"Corruption detected! Free inode 0x%llx not marked free! (mode 0x%x)",
 418				ip->i_ino, VFS_I(ip)->i_mode);
 419			xfs_agno_mark_sick(ip->i_mount,
 420					XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
 421					XFS_SICK_AG_INOBT);
 422			return -EFSCORRUPTED;
 423		}
 424
 425		if (ip->i_nblocks != 0) {
 426			xfs_warn(ip->i_mount,
 427"Corruption detected! Free inode 0x%llx has blocks allocated!",
 428				ip->i_ino);
 429			xfs_agno_mark_sick(ip->i_mount,
 430					XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
 431					XFS_SICK_AG_INOBT);
 432			return -EFSCORRUPTED;
 433		}
 434		return 0;
 435	}
 436
 437	/* should be an allocated inode */
 438	if (VFS_I(ip)->i_mode == 0)
 439		return -ENOENT;
 440
 441	return 0;
 442}
 443
 444/* Make all pending inactivation work start immediately. */
 445static bool
 446xfs_inodegc_queue_all(
 447	struct xfs_mount	*mp)
 448{
 449	struct xfs_inodegc	*gc;
 450	int			cpu;
 451	bool			ret = false;
 452
 453	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
 454		gc = per_cpu_ptr(mp->m_inodegc, cpu);
 455		if (!llist_empty(&gc->list)) {
 456			mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
 457			ret = true;
 458		}
 459	}
 460
 461	return ret;
 462}
 463
 464/* Wait for all queued work and collect errors */
 465static int
 466xfs_inodegc_wait_all(
 467	struct xfs_mount	*mp)
 468{
 469	int			cpu;
 470	int			error = 0;
 471
 472	flush_workqueue(mp->m_inodegc_wq);
 473	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
 474		struct xfs_inodegc	*gc;
 475
 476		gc = per_cpu_ptr(mp->m_inodegc, cpu);
 477		if (gc->error && !error)
 478			error = gc->error;
 479		gc->error = 0;
 480	}
 481
 482	return error;
 483}
 484
 485/*
 486 * Check the validity of the inode we just found it the cache
 487 */
 488static int
 489xfs_iget_cache_hit(
 490	struct xfs_perag	*pag,
 491	struct xfs_inode	*ip,
 492	xfs_ino_t		ino,
 493	int			flags,
 494	int			lock_flags) __releases(RCU)
 495{
 496	struct inode		*inode = VFS_I(ip);
 497	struct xfs_mount	*mp = ip->i_mount;
 498	int			error;
 499
 500	/*
 501	 * check for re-use of an inode within an RCU grace period due to the
 502	 * radix tree nodes not being updated yet. We monitor for this by
 503	 * setting the inode number to zero before freeing the inode structure.
 504	 * If the inode has been reallocated and set up, then the inode number
 505	 * will not match, so check for that, too.
 506	 */
 507	spin_lock(&ip->i_flags_lock);
 508	if (ip->i_ino != ino)
 509		goto out_skip;
 510
 511	/*
 512	 * If we are racing with another cache hit that is currently
 513	 * instantiating this inode or currently recycling it out of
 514	 * reclaimable state, wait for the initialisation to complete
 515	 * before continuing.
 516	 *
 517	 * If we're racing with the inactivation worker we also want to wait.
 518	 * If we're creating a new file, it's possible that the worker
 519	 * previously marked the inode as free on disk but hasn't finished
 520	 * updating the incore state yet.  The AGI buffer will be dirty and
 521	 * locked to the icreate transaction, so a synchronous push of the
 522	 * inodegc workers would result in deadlock.  For a regular iget, the
 523	 * worker is running already, so we might as well wait.
 524	 *
 525	 * XXX(hch): eventually we should do something equivalent to
 526	 *	     wait_on_inode to wait for these flags to be cleared
 527	 *	     instead of polling for it.
 528	 */
 529	if (ip->i_flags & (XFS_INEW | XFS_IRECLAIM | XFS_INACTIVATING))
 530		goto out_skip;
 531
 532	if (ip->i_flags & XFS_NEED_INACTIVE) {
 533		/* Unlinked inodes cannot be re-grabbed. */
 534		if (VFS_I(ip)->i_nlink == 0) {
 535			error = -ENOENT;
 536			goto out_error;
 537		}
 538		goto out_inodegc_flush;
 539	}
 540
 541	/*
 542	 * Check the inode free state is valid. This also detects lookup
 543	 * racing with unlinks.
 544	 */
 545	error = xfs_iget_check_free_state(ip, flags);
 546	if (error)
 547		goto out_error;
 548
 549	/* Skip inodes that have no vfs state. */
 550	if ((flags & XFS_IGET_INCORE) &&
 551	    (ip->i_flags & XFS_IRECLAIMABLE))
 552		goto out_skip;
 553
 554	/* The inode fits the selection criteria; process it. */
 555	if (ip->i_flags & XFS_IRECLAIMABLE) {
 556		/* Drops i_flags_lock and RCU read lock. */
 557		error = xfs_iget_recycle(pag, ip);
 558		if (error == -EAGAIN)
 559			goto out_skip;
 560		if (error)
 561			return error;
 562	} else {
 563		/* If the VFS inode is being torn down, pause and try again. */
 564		if (!igrab(inode))
 565			goto out_skip;
 566
 567		/* We've got a live one. */
 568		spin_unlock(&ip->i_flags_lock);
 569		rcu_read_unlock();
 570		trace_xfs_iget_hit(ip);
 571	}
 572
 573	if (lock_flags != 0)
 574		xfs_ilock(ip, lock_flags);
 575
 576	if (!(flags & XFS_IGET_INCORE))
 577		xfs_iflags_clear(ip, XFS_ISTALE);
 578	XFS_STATS_INC(mp, xs_ig_found);
 579
 580	return 0;
 581
 582out_skip:
 583	trace_xfs_iget_skip(ip);
 584	XFS_STATS_INC(mp, xs_ig_frecycle);
 585	error = -EAGAIN;
 586out_error:
 587	spin_unlock(&ip->i_flags_lock);
 588	rcu_read_unlock();
 589	return error;
 590
 591out_inodegc_flush:
 592	spin_unlock(&ip->i_flags_lock);
 593	rcu_read_unlock();
 594	/*
 595	 * Do not wait for the workers, because the caller could hold an AGI
 596	 * buffer lock.  We're just going to sleep in a loop anyway.
 597	 */
 598	if (xfs_is_inodegc_enabled(mp))
 599		xfs_inodegc_queue_all(mp);
 600	return -EAGAIN;
 601}
 602
 603static int
 604xfs_iget_cache_miss(
 605	struct xfs_mount	*mp,
 606	struct xfs_perag	*pag,
 607	xfs_trans_t		*tp,
 608	xfs_ino_t		ino,
 609	struct xfs_inode	**ipp,
 610	int			flags,
 611	int			lock_flags)
 612{
 613	struct xfs_inode	*ip;
 614	int			error;
 615	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ino);
 616	int			iflags;
 617
 618	ip = xfs_inode_alloc(mp, ino);
 619	if (!ip)
 620		return -ENOMEM;
 621
 622	error = xfs_imap(pag, tp, ip->i_ino, &ip->i_imap, flags);
 623	if (error)
 624		goto out_destroy;
 625
 626	/*
 627	 * For version 5 superblocks, if we are initialising a new inode and we
 628	 * are not utilising the XFS_FEAT_IKEEP inode cluster mode, we can
 629	 * simply build the new inode core with a random generation number.
 630	 *
 631	 * For version 4 (and older) superblocks, log recovery is dependent on
 632	 * the i_flushiter field being initialised from the current on-disk
 633	 * value and hence we must also read the inode off disk even when
 634	 * initializing new inodes.
 635	 */
 636	if (xfs_has_v3inodes(mp) &&
 637	    (flags & XFS_IGET_CREATE) && !xfs_has_ikeep(mp)) {
 638		VFS_I(ip)->i_generation = get_random_u32();
 639	} else {
 640		struct xfs_buf		*bp;
 641
 642		error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &bp);
 643		if (error)
 644			goto out_destroy;
 645
 646		error = xfs_inode_from_disk(ip,
 647				xfs_buf_offset(bp, ip->i_imap.im_boffset));
 648		if (!error)
 649			xfs_buf_set_ref(bp, XFS_INO_REF);
 650		else
 651			xfs_inode_mark_sick(ip, XFS_SICK_INO_CORE);
 652		xfs_trans_brelse(tp, bp);
 653
 654		if (error)
 655			goto out_destroy;
 656	}
 657
 658	trace_xfs_iget_miss(ip);
 659
 660	/*
 661	 * Check the inode free state is valid. This also detects lookup
 662	 * racing with unlinks.
 663	 */
 664	error = xfs_iget_check_free_state(ip, flags);
 665	if (error)
 666		goto out_destroy;
 667
 668	/*
 669	 * Preload the radix tree so we can insert safely under the
 670	 * write spinlock. Note that we cannot sleep inside the preload
 671	 * region.
 672	 */
 673	if (radix_tree_preload(GFP_KERNEL | __GFP_NOLOCKDEP)) {
 674		error = -EAGAIN;
 675		goto out_destroy;
 676	}
 677
 678	/*
 679	 * Because the inode hasn't been added to the radix-tree yet it can't
 680	 * be found by another thread, so we can do the non-sleeping lock here.
 681	 */
 682	if (lock_flags) {
 683		if (!xfs_ilock_nowait(ip, lock_flags))
 684			BUG();
 685	}
 686
 687	/*
 688	 * These values must be set before inserting the inode into the radix
 689	 * tree as the moment it is inserted a concurrent lookup (allowed by the
 690	 * RCU locking mechanism) can find it and that lookup must see that this
 691	 * is an inode currently under construction (i.e. that XFS_INEW is set).
 692	 * The ip->i_flags_lock that protects the XFS_INEW flag forms the
 693	 * memory barrier that ensures this detection works correctly at lookup
 694	 * time.
 695	 */
 696	iflags = XFS_INEW;
 697	if (flags & XFS_IGET_DONTCACHE)
 698		d_mark_dontcache(VFS_I(ip));
 699	ip->i_udquot = NULL;
 700	ip->i_gdquot = NULL;
 701	ip->i_pdquot = NULL;
 702	xfs_iflags_set(ip, iflags);
 703
 704	/* insert the new inode */
 705	spin_lock(&pag->pag_ici_lock);
 706	error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
 707	if (unlikely(error)) {
 708		WARN_ON(error != -EEXIST);
 709		XFS_STATS_INC(mp, xs_ig_dup);
 710		error = -EAGAIN;
 711		goto out_preload_end;
 712	}
 713	spin_unlock(&pag->pag_ici_lock);
 714	radix_tree_preload_end();
 715
 716	*ipp = ip;
 717	return 0;
 718
 719out_preload_end:
 720	spin_unlock(&pag->pag_ici_lock);
 721	radix_tree_preload_end();
 722	if (lock_flags)
 723		xfs_iunlock(ip, lock_flags);
 724out_destroy:
 725	__destroy_inode(VFS_I(ip));
 726	xfs_inode_free(ip);
 727	return error;
 728}
 729
 730/*
 731 * Look up an inode by number in the given file system.  The inode is looked up
 732 * in the cache held in each AG.  If the inode is found in the cache, initialise
 733 * the vfs inode if necessary.
 734 *
 735 * If it is not in core, read it in from the file system's device, add it to the
 736 * cache and initialise the vfs inode.
 737 *
 738 * The inode is locked according to the value of the lock_flags parameter.
 739 * Inode lookup is only done during metadata operations and not as part of the
 740 * data IO path. Hence we only allow locking of the XFS_ILOCK during lookup.
 741 */
 742int
 743xfs_iget(
 744	struct xfs_mount	*mp,
 745	struct xfs_trans	*tp,
 746	xfs_ino_t		ino,
 747	uint			flags,
 748	uint			lock_flags,
 749	struct xfs_inode	**ipp)
 750{
 751	struct xfs_inode	*ip;
 752	struct xfs_perag	*pag;
 753	xfs_agino_t		agino;
 754	int			error;
 755
 756	ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
 757
 758	/* reject inode numbers outside existing AGs */
 759	if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
 760		return -EINVAL;
 761
 762	XFS_STATS_INC(mp, xs_ig_attempts);
 763
 764	/* get the perag structure and ensure that it's inode capable */
 765	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
 766	agino = XFS_INO_TO_AGINO(mp, ino);
 767
 768again:
 769	error = 0;
 770	rcu_read_lock();
 771	ip = radix_tree_lookup(&pag->pag_ici_root, agino);
 772
 773	if (ip) {
 774		error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
 775		if (error)
 776			goto out_error_or_again;
 777	} else {
 778		rcu_read_unlock();
 779		if (flags & XFS_IGET_INCORE) {
 780			error = -ENODATA;
 781			goto out_error_or_again;
 782		}
 783		XFS_STATS_INC(mp, xs_ig_missed);
 784
 785		error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
 786							flags, lock_flags);
 787		if (error)
 788			goto out_error_or_again;
 789	}
 790	xfs_perag_put(pag);
 791
 792	*ipp = ip;
 793
 794	/*
 795	 * If we have a real type for an on-disk inode, we can setup the inode
 796	 * now.	 If it's a new inode being created, xfs_init_new_inode will
 797	 * handle it.
 798	 */
 799	if (xfs_iflags_test(ip, XFS_INEW) && VFS_I(ip)->i_mode != 0)
 800		xfs_setup_existing_inode(ip);
 801	return 0;
 802
 803out_error_or_again:
 804	if (!(flags & (XFS_IGET_INCORE | XFS_IGET_NORETRY)) &&
 805	    error == -EAGAIN) {
 806		delay(1);
 807		goto again;
 808	}
 809	xfs_perag_put(pag);
 810	return error;
 811}
 812
 813/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 814 * Grab the inode for reclaim exclusively.
 815 *
 816 * We have found this inode via a lookup under RCU, so the inode may have
 817 * already been freed, or it may be in the process of being recycled by
 818 * xfs_iget(). In both cases, the inode will have XFS_IRECLAIM set. If the inode
 819 * has been fully recycled by the time we get the i_flags_lock, XFS_IRECLAIMABLE
 820 * will not be set. Hence we need to check for both these flag conditions to
 821 * avoid inodes that are no longer reclaim candidates.
 822 *
 823 * Note: checking for other state flags here, under the i_flags_lock or not, is
 824 * racy and should be avoided. Those races should be resolved only after we have
 825 * ensured that we are able to reclaim this inode and the world can see that we
 826 * are going to reclaim it.
 827 *
 828 * Return true if we grabbed it, false otherwise.
 829 */
 830static bool
 831xfs_reclaim_igrab(
 832	struct xfs_inode	*ip,
 833	struct xfs_icwalk	*icw)
 834{
 835	ASSERT(rcu_read_lock_held());
 836
 837	spin_lock(&ip->i_flags_lock);
 838	if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
 839	    __xfs_iflags_test(ip, XFS_IRECLAIM)) {
 840		/* not a reclaim candidate. */
 841		spin_unlock(&ip->i_flags_lock);
 842		return false;
 843	}
 844
 845	/* Don't reclaim a sick inode unless the caller asked for it. */
 846	if (ip->i_sick &&
 847	    (!icw || !(icw->icw_flags & XFS_ICWALK_FLAG_RECLAIM_SICK))) {
 848		spin_unlock(&ip->i_flags_lock);
 849		return false;
 850	}
 851
 852	__xfs_iflags_set(ip, XFS_IRECLAIM);
 853	spin_unlock(&ip->i_flags_lock);
 854	return true;
 855}
 856
 857/*
 858 * Inode reclaim is non-blocking, so the default action if progress cannot be
 859 * made is to "requeue" the inode for reclaim by unlocking it and clearing the
 860 * XFS_IRECLAIM flag.  If we are in a shutdown state, we don't care about
 861 * blocking anymore and hence we can wait for the inode to be able to reclaim
 862 * it.
 863 *
 864 * We do no IO here - if callers require inodes to be cleaned they must push the
 865 * AIL first to trigger writeback of dirty inodes.  This enables writeback to be
 866 * done in the background in a non-blocking manner, and enables memory reclaim
 867 * to make progress without blocking.
 868 */
 869static void
 870xfs_reclaim_inode(
 871	struct xfs_inode	*ip,
 872	struct xfs_perag	*pag)
 873{
 874	xfs_ino_t		ino = ip->i_ino; /* for radix_tree_delete */
 875
 876	if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
 877		goto out;
 878	if (xfs_iflags_test_and_set(ip, XFS_IFLUSHING))
 879		goto out_iunlock;
 880
 881	/*
 882	 * Check for log shutdown because aborting the inode can move the log
 883	 * tail and corrupt in memory state. This is fine if the log is shut
 884	 * down, but if the log is still active and only the mount is shut down
 885	 * then the in-memory log tail movement caused by the abort can be
 886	 * incorrectly propagated to disk.
 887	 */
 888	if (xlog_is_shutdown(ip->i_mount->m_log)) {
 889		xfs_iunpin_wait(ip);
 890		xfs_iflush_shutdown_abort(ip);
 891		goto reclaim;
 892	}
 893	if (xfs_ipincount(ip))
 894		goto out_clear_flush;
 895	if (!xfs_inode_clean(ip))
 896		goto out_clear_flush;
 897
 898	xfs_iflags_clear(ip, XFS_IFLUSHING);
 899reclaim:
 900	trace_xfs_inode_reclaiming(ip);
 901
 902	/*
 903	 * Because we use RCU freeing we need to ensure the inode always appears
 904	 * to be reclaimed with an invalid inode number when in the free state.
 905	 * We do this as early as possible under the ILOCK so that
 906	 * xfs_iflush_cluster() and xfs_ifree_cluster() can be guaranteed to
 907	 * detect races with us here. By doing this, we guarantee that once
 908	 * xfs_iflush_cluster() or xfs_ifree_cluster() has locked XFS_ILOCK that
 909	 * it will see either a valid inode that will serialise correctly, or it
 910	 * will see an invalid inode that it can skip.
 911	 */
 912	spin_lock(&ip->i_flags_lock);
 913	ip->i_flags = XFS_IRECLAIM;
 914	ip->i_ino = 0;
 915	ip->i_sick = 0;
 916	ip->i_checked = 0;
 917	spin_unlock(&ip->i_flags_lock);
 918
 919	ASSERT(!ip->i_itemp || ip->i_itemp->ili_item.li_buf == NULL);
 920	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 921
 922	XFS_STATS_INC(ip->i_mount, xs_ig_reclaims);
 923	/*
 924	 * Remove the inode from the per-AG radix tree.
 925	 *
 926	 * Because radix_tree_delete won't complain even if the item was never
 927	 * added to the tree assert that it's been there before to catch
 928	 * problems with the inode life time early on.
 929	 */
 930	spin_lock(&pag->pag_ici_lock);
 931	if (!radix_tree_delete(&pag->pag_ici_root,
 932				XFS_INO_TO_AGINO(ip->i_mount, ino)))
 933		ASSERT(0);
 934	xfs_perag_clear_inode_tag(pag, NULLAGINO, XFS_ICI_RECLAIM_TAG);
 935	spin_unlock(&pag->pag_ici_lock);
 936
 937	/*
 938	 * Here we do an (almost) spurious inode lock in order to coordinate
 939	 * with inode cache radix tree lookups.  This is because the lookup
 940	 * can reference the inodes in the cache without taking references.
 941	 *
 942	 * We make that OK here by ensuring that we wait until the inode is
 943	 * unlocked after the lookup before we go ahead and free it.
 944	 */
 945	xfs_ilock(ip, XFS_ILOCK_EXCL);
 946	ASSERT(!ip->i_udquot && !ip->i_gdquot && !ip->i_pdquot);
 947	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 948	ASSERT(xfs_inode_clean(ip));
 949
 950	__xfs_inode_free(ip);
 951	return;
 952
 953out_clear_flush:
 954	xfs_iflags_clear(ip, XFS_IFLUSHING);
 955out_iunlock:
 956	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 957out:
 958	xfs_iflags_clear(ip, XFS_IRECLAIM);
 959}
 960
 961/* Reclaim sick inodes if we're unmounting or the fs went down. */
 962static inline bool
 963xfs_want_reclaim_sick(
 964	struct xfs_mount	*mp)
 965{
 966	return xfs_is_unmounting(mp) || xfs_has_norecovery(mp) ||
 967	       xfs_is_shutdown(mp);
 968}
 969
 970void
 971xfs_reclaim_inodes(
 972	struct xfs_mount	*mp)
 973{
 974	struct xfs_icwalk	icw = {
 975		.icw_flags	= 0,
 976	};
 977
 978	if (xfs_want_reclaim_sick(mp))
 979		icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
 980
 981	while (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
 982		xfs_ail_push_all_sync(mp->m_ail);
 983		xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
 984	}
 985}
 986
 987/*
 988 * The shrinker infrastructure determines how many inodes we should scan for
 989 * reclaim. We want as many clean inodes ready to reclaim as possible, so we
 990 * push the AIL here. We also want to proactively free up memory if we can to
 991 * minimise the amount of work memory reclaim has to do so we kick the
 992 * background reclaim if it isn't already scheduled.
 993 */
 994long
 995xfs_reclaim_inodes_nr(
 996	struct xfs_mount	*mp,
 997	unsigned long		nr_to_scan)
 998{
 999	struct xfs_icwalk	icw = {
1000		.icw_flags	= XFS_ICWALK_FLAG_SCAN_LIMIT,
1001		.icw_scan_limit	= min_t(unsigned long, LONG_MAX, nr_to_scan),
1002	};
1003
1004	if (xfs_want_reclaim_sick(mp))
1005		icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
1006
1007	/* kick background reclaimer and push the AIL */
1008	xfs_reclaim_work_queue(mp);
1009	xfs_ail_push_all(mp->m_ail);
1010
1011	xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
1012	return 0;
1013}
1014
1015/*
1016 * Return the number of reclaimable inodes in the filesystem for
1017 * the shrinker to determine how much to reclaim.
1018 */
1019long
1020xfs_reclaim_inodes_count(
1021	struct xfs_mount	*mp)
1022{
1023	struct xfs_perag	*pag;
1024	xfs_agnumber_t		ag = 0;
1025	long			reclaimable = 0;
 
1026
1027	while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
1028		ag = pag->pag_agno + 1;
 
1029		reclaimable += pag->pag_ici_reclaimable;
1030		xfs_perag_put(pag);
1031	}
 
 
1032	return reclaimable;
1033}
1034
1035STATIC bool
1036xfs_icwalk_match_id(
1037	struct xfs_inode	*ip,
1038	struct xfs_icwalk	*icw)
1039{
1040	if ((icw->icw_flags & XFS_ICWALK_FLAG_UID) &&
1041	    !uid_eq(VFS_I(ip)->i_uid, icw->icw_uid))
1042		return false;
1043
1044	if ((icw->icw_flags & XFS_ICWALK_FLAG_GID) &&
1045	    !gid_eq(VFS_I(ip)->i_gid, icw->icw_gid))
1046		return false;
1047
1048	if ((icw->icw_flags & XFS_ICWALK_FLAG_PRID) &&
1049	    ip->i_projid != icw->icw_prid)
1050		return false;
1051
1052	return true;
1053}
1054
1055/*
1056 * A union-based inode filtering algorithm. Process the inode if any of the
1057 * criteria match. This is for global/internal scans only.
1058 */
1059STATIC bool
1060xfs_icwalk_match_id_union(
1061	struct xfs_inode	*ip,
1062	struct xfs_icwalk	*icw)
1063{
1064	if ((icw->icw_flags & XFS_ICWALK_FLAG_UID) &&
1065	    uid_eq(VFS_I(ip)->i_uid, icw->icw_uid))
1066		return true;
1067
1068	if ((icw->icw_flags & XFS_ICWALK_FLAG_GID) &&
1069	    gid_eq(VFS_I(ip)->i_gid, icw->icw_gid))
1070		return true;
1071
1072	if ((icw->icw_flags & XFS_ICWALK_FLAG_PRID) &&
1073	    ip->i_projid == icw->icw_prid)
1074		return true;
1075
1076	return false;
1077}
1078
1079/*
1080 * Is this inode @ip eligible for eof/cow block reclamation, given some
1081 * filtering parameters @icw?  The inode is eligible if @icw is null or
1082 * if the predicate functions match.
1083 */
1084static bool
1085xfs_icwalk_match(
1086	struct xfs_inode	*ip,
1087	struct xfs_icwalk	*icw)
1088{
1089	bool			match;
1090
1091	if (!icw)
1092		return true;
1093
1094	if (icw->icw_flags & XFS_ICWALK_FLAG_UNION)
1095		match = xfs_icwalk_match_id_union(ip, icw);
1096	else
1097		match = xfs_icwalk_match_id(ip, icw);
1098	if (!match)
1099		return false;
1100
1101	/* skip the inode if the file size is too small */
1102	if ((icw->icw_flags & XFS_ICWALK_FLAG_MINFILESIZE) &&
1103	    XFS_ISIZE(ip) < icw->icw_min_file_size)
1104		return false;
1105
1106	return true;
1107}
1108
1109/*
1110 * This is a fast pass over the inode cache to try to get reclaim moving on as
1111 * many inodes as possible in a short period of time. It kicks itself every few
1112 * seconds, as well as being kicked by the inode cache shrinker when memory
1113 * goes low.
1114 */
1115void
1116xfs_reclaim_worker(
1117	struct work_struct *work)
1118{
1119	struct xfs_mount *mp = container_of(to_delayed_work(work),
1120					struct xfs_mount, m_reclaim_work);
1121
1122	xfs_icwalk(mp, XFS_ICWALK_RECLAIM, NULL);
1123	xfs_reclaim_work_queue(mp);
1124}
1125
1126STATIC int
1127xfs_inode_free_eofblocks(
1128	struct xfs_inode	*ip,
1129	struct xfs_icwalk	*icw,
1130	unsigned int		*lockflags)
1131{
1132	bool			wait;
1133
1134	wait = icw && (icw->icw_flags & XFS_ICWALK_FLAG_SYNC);
1135
1136	if (!xfs_iflags_test(ip, XFS_IEOFBLOCKS))
1137		return 0;
1138
1139	/*
1140	 * If the mapping is dirty the operation can block and wait for some
1141	 * time. Unless we are waiting, skip it.
1142	 */
1143	if (!wait && mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY))
1144		return 0;
1145
1146	if (!xfs_icwalk_match(ip, icw))
1147		return 0;
1148
1149	/*
1150	 * If the caller is waiting, return -EAGAIN to keep the background
1151	 * scanner moving and revisit the inode in a subsequent pass.
1152	 */
1153	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
1154		if (wait)
1155			return -EAGAIN;
1156		return 0;
1157	}
1158	*lockflags |= XFS_IOLOCK_EXCL;
1159
1160	if (xfs_can_free_eofblocks(ip, false))
1161		return xfs_free_eofblocks(ip);
1162
1163	/* inode could be preallocated or append-only */
1164	trace_xfs_inode_free_eofblocks_invalid(ip);
1165	xfs_inode_clear_eofblocks_tag(ip);
1166	return 0;
1167}
1168
1169static void
1170xfs_blockgc_set_iflag(
1171	struct xfs_inode	*ip,
1172	unsigned long		iflag)
1173{
1174	struct xfs_mount	*mp = ip->i_mount;
1175	struct xfs_perag	*pag;
1176
1177	ASSERT((iflag & ~(XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0);
1178
1179	/*
1180	 * Don't bother locking the AG and looking up in the radix trees
1181	 * if we already know that we have the tag set.
1182	 */
1183	if (ip->i_flags & iflag)
1184		return;
1185	spin_lock(&ip->i_flags_lock);
1186	ip->i_flags |= iflag;
1187	spin_unlock(&ip->i_flags_lock);
1188
1189	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1190	spin_lock(&pag->pag_ici_lock);
1191
1192	xfs_perag_set_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
1193			XFS_ICI_BLOCKGC_TAG);
1194
1195	spin_unlock(&pag->pag_ici_lock);
1196	xfs_perag_put(pag);
1197}
1198
1199void
1200xfs_inode_set_eofblocks_tag(
1201	xfs_inode_t	*ip)
1202{
1203	trace_xfs_inode_set_eofblocks_tag(ip);
1204	return xfs_blockgc_set_iflag(ip, XFS_IEOFBLOCKS);
1205}
1206
1207static void
1208xfs_blockgc_clear_iflag(
1209	struct xfs_inode	*ip,
1210	unsigned long		iflag)
1211{
1212	struct xfs_mount	*mp = ip->i_mount;
1213	struct xfs_perag	*pag;
1214	bool			clear_tag;
1215
1216	ASSERT((iflag & ~(XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0);
1217
1218	spin_lock(&ip->i_flags_lock);
1219	ip->i_flags &= ~iflag;
1220	clear_tag = (ip->i_flags & (XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0;
1221	spin_unlock(&ip->i_flags_lock);
1222
1223	if (!clear_tag)
1224		return;
1225
1226	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1227	spin_lock(&pag->pag_ici_lock);
1228
1229	xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
1230			XFS_ICI_BLOCKGC_TAG);
1231
1232	spin_unlock(&pag->pag_ici_lock);
1233	xfs_perag_put(pag);
1234}
1235
1236void
1237xfs_inode_clear_eofblocks_tag(
1238	xfs_inode_t	*ip)
1239{
1240	trace_xfs_inode_clear_eofblocks_tag(ip);
1241	return xfs_blockgc_clear_iflag(ip, XFS_IEOFBLOCKS);
1242}
1243
1244/*
1245 * Set ourselves up to free CoW blocks from this file.  If it's already clean
1246 * then we can bail out quickly, but otherwise we must back off if the file
1247 * is undergoing some kind of write.
1248 */
1249static bool
1250xfs_prep_free_cowblocks(
1251	struct xfs_inode	*ip)
 
1252{
 
 
 
 
1253	/*
1254	 * Just clear the tag if we have an empty cow fork or none at all. It's
1255	 * possible the inode was fully unshared since it was originally tagged.
1256	 */
1257	if (!xfs_inode_has_cow_data(ip)) {
1258		trace_xfs_inode_free_cowblocks_invalid(ip);
1259		xfs_inode_clear_cowblocks_tag(ip);
1260		return false;
1261	}
1262
1263	/*
1264	 * If the mapping is dirty or under writeback we cannot touch the
1265	 * CoW fork.  Leave it alone if we're in the midst of a directio.
 
 
 
 
 
 
 
 
 
 
1266	 */
1267	if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) ||
1268	    mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) ||
1269	    mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) ||
1270	    atomic_read(&VFS_I(ip)->i_dio_count))
1271		return false;
1272
1273	return true;
1274}
1275
1276/*
1277 * Automatic CoW Reservation Freeing
1278 *
1279 * These functions automatically garbage collect leftover CoW reservations
1280 * that were made on behalf of a cowextsize hint when we start to run out
1281 * of quota or when the reservations sit around for too long.  If the file
1282 * has dirty pages or is undergoing writeback, its CoW reservations will
1283 * be retained.
1284 *
1285 * The actual garbage collection piggybacks off the same code that runs
1286 * the speculative EOF preallocation garbage collector.
1287 */
1288STATIC int
1289xfs_inode_free_cowblocks(
1290	struct xfs_inode	*ip,
1291	struct xfs_icwalk	*icw,
1292	unsigned int		*lockflags)
1293{
1294	bool			wait;
1295	int			ret = 0;
1296
1297	wait = icw && (icw->icw_flags & XFS_ICWALK_FLAG_SYNC);
1298
1299	if (!xfs_iflags_test(ip, XFS_ICOWBLOCKS))
1300		return 0;
1301
1302	if (!xfs_prep_free_cowblocks(ip))
1303		return 0;
1304
1305	if (!xfs_icwalk_match(ip, icw))
1306		return 0;
1307
1308	/*
1309	 * If the caller is waiting, return -EAGAIN to keep the background
1310	 * scanner moving and revisit the inode in a subsequent pass.
1311	 */
1312	if (!(*lockflags & XFS_IOLOCK_EXCL) &&
1313	    !xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
1314		if (wait)
1315			return -EAGAIN;
1316		return 0;
1317	}
1318	*lockflags |= XFS_IOLOCK_EXCL;
1319
1320	if (!xfs_ilock_nowait(ip, XFS_MMAPLOCK_EXCL)) {
1321		if (wait)
1322			return -EAGAIN;
1323		return 0;
1324	}
1325	*lockflags |= XFS_MMAPLOCK_EXCL;
1326
1327	/*
1328	 * Check again, nobody else should be able to dirty blocks or change
1329	 * the reflink iflag now that we have the first two locks held.
1330	 */
1331	if (xfs_prep_free_cowblocks(ip))
1332		ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false);
1333	return ret;
1334}
1335
1336void
1337xfs_inode_set_cowblocks_tag(
1338	xfs_inode_t	*ip)
1339{
1340	trace_xfs_inode_set_cowblocks_tag(ip);
1341	return xfs_blockgc_set_iflag(ip, XFS_ICOWBLOCKS);
1342}
1343
1344void
1345xfs_inode_clear_cowblocks_tag(
1346	xfs_inode_t	*ip)
1347{
1348	trace_xfs_inode_clear_cowblocks_tag(ip);
1349	return xfs_blockgc_clear_iflag(ip, XFS_ICOWBLOCKS);
1350}
1351
1352/* Disable post-EOF and CoW block auto-reclamation. */
1353void
1354xfs_blockgc_stop(
1355	struct xfs_mount	*mp)
1356{
1357	struct xfs_perag	*pag;
1358	xfs_agnumber_t		agno;
1359
1360	if (!xfs_clear_blockgc_enabled(mp))
1361		return;
1362
1363	for_each_perag(mp, agno, pag)
1364		cancel_delayed_work_sync(&pag->pag_blockgc_work);
1365	trace_xfs_blockgc_stop(mp, __return_address);
1366}
1367
1368/* Enable post-EOF and CoW block auto-reclamation. */
1369void
1370xfs_blockgc_start(
1371	struct xfs_mount	*mp)
1372{
1373	struct xfs_perag	*pag;
1374	xfs_agnumber_t		agno;
1375
1376	if (xfs_set_blockgc_enabled(mp))
1377		return;
1378
1379	trace_xfs_blockgc_start(mp, __return_address);
1380	for_each_perag_tag(mp, agno, pag, XFS_ICI_BLOCKGC_TAG)
1381		xfs_blockgc_queue(pag);
1382}
1383
1384/* Don't try to run block gc on an inode that's in any of these states. */
1385#define XFS_BLOCKGC_NOGRAB_IFLAGS	(XFS_INEW | \
1386					 XFS_NEED_INACTIVE | \
1387					 XFS_INACTIVATING | \
1388					 XFS_IRECLAIMABLE | \
1389					 XFS_IRECLAIM)
1390/*
1391 * Decide if the given @ip is eligible for garbage collection of speculative
1392 * preallocations, and grab it if so.  Returns true if it's ready to go or
1393 * false if we should just ignore it.
1394 */
1395static bool
1396xfs_blockgc_igrab(
1397	struct xfs_inode	*ip)
1398{
1399	struct inode		*inode = VFS_I(ip);
1400
1401	ASSERT(rcu_read_lock_held());
1402
1403	/* Check for stale RCU freed inode */
1404	spin_lock(&ip->i_flags_lock);
1405	if (!ip->i_ino)
1406		goto out_unlock_noent;
1407
1408	if (ip->i_flags & XFS_BLOCKGC_NOGRAB_IFLAGS)
1409		goto out_unlock_noent;
1410	spin_unlock(&ip->i_flags_lock);
1411
1412	/* nothing to sync during shutdown */
1413	if (xfs_is_shutdown(ip->i_mount))
1414		return false;
1415
1416	/* If we can't grab the inode, it must on it's way to reclaim. */
1417	if (!igrab(inode))
1418		return false;
1419
1420	/* inode is valid */
1421	return true;
1422
1423out_unlock_noent:
1424	spin_unlock(&ip->i_flags_lock);
1425	return false;
1426}
1427
1428/* Scan one incore inode for block preallocations that we can remove. */
1429static int
1430xfs_blockgc_scan_inode(
1431	struct xfs_inode	*ip,
1432	struct xfs_icwalk	*icw)
1433{
1434	unsigned int		lockflags = 0;
1435	int			error;
1436
1437	error = xfs_inode_free_eofblocks(ip, icw, &lockflags);
1438	if (error)
1439		goto unlock;
1440
1441	error = xfs_inode_free_cowblocks(ip, icw, &lockflags);
1442unlock:
1443	if (lockflags)
1444		xfs_iunlock(ip, lockflags);
1445	xfs_irele(ip);
1446	return error;
1447}
1448
1449/* Background worker that trims preallocated space. */
1450void
1451xfs_blockgc_worker(
1452	struct work_struct	*work)
1453{
1454	struct xfs_perag	*pag = container_of(to_delayed_work(work),
1455					struct xfs_perag, pag_blockgc_work);
1456	struct xfs_mount	*mp = pag->pag_mount;
1457	int			error;
1458
1459	trace_xfs_blockgc_worker(mp, __return_address);
1460
1461	error = xfs_icwalk_ag(pag, XFS_ICWALK_BLOCKGC, NULL);
1462	if (error)
1463		xfs_info(mp, "AG %u preallocation gc worker failed, err=%d",
1464				pag->pag_agno, error);
1465	xfs_blockgc_queue(pag);
1466}
1467
1468/*
1469 * Try to free space in the filesystem by purging inactive inodes, eofblocks
1470 * and cowblocks.
1471 */
1472int
1473xfs_blockgc_free_space(
1474	struct xfs_mount	*mp,
1475	struct xfs_icwalk	*icw)
1476{
1477	int			error;
1478
1479	trace_xfs_blockgc_free_space(mp, icw, _RET_IP_);
1480
1481	error = xfs_icwalk(mp, XFS_ICWALK_BLOCKGC, icw);
1482	if (error)
1483		return error;
1484
1485	return xfs_inodegc_flush(mp);
1486}
1487
1488/*
1489 * Reclaim all the free space that we can by scheduling the background blockgc
1490 * and inodegc workers immediately and waiting for them all to clear.
1491 */
1492int
1493xfs_blockgc_flush_all(
1494	struct xfs_mount	*mp)
1495{
1496	struct xfs_perag	*pag;
1497	xfs_agnumber_t		agno;
1498
1499	trace_xfs_blockgc_flush_all(mp, __return_address);
1500
1501	/*
1502	 * For each blockgc worker, move its queue time up to now.  If it
1503	 * wasn't queued, it will not be requeued.  Then flush whatever's
1504	 * left.
1505	 */
1506	for_each_perag_tag(mp, agno, pag, XFS_ICI_BLOCKGC_TAG)
1507		mod_delayed_work(pag->pag_mount->m_blockgc_wq,
1508				&pag->pag_blockgc_work, 0);
1509
1510	for_each_perag_tag(mp, agno, pag, XFS_ICI_BLOCKGC_TAG)
1511		flush_delayed_work(&pag->pag_blockgc_work);
1512
1513	return xfs_inodegc_flush(mp);
1514}
1515
1516/*
1517 * Run cow/eofblocks scans on the supplied dquots.  We don't know exactly which
1518 * quota caused an allocation failure, so we make a best effort by including
1519 * each quota under low free space conditions (less than 1% free space) in the
1520 * scan.
1521 *
1522 * Callers must not hold any inode's ILOCK.  If requesting a synchronous scan
1523 * (XFS_ICWALK_FLAG_SYNC), the caller also must not hold any inode's IOLOCK or
1524 * MMAPLOCK.
1525 */
1526int
1527xfs_blockgc_free_dquots(
1528	struct xfs_mount	*mp,
1529	struct xfs_dquot	*udqp,
1530	struct xfs_dquot	*gdqp,
1531	struct xfs_dquot	*pdqp,
1532	unsigned int		iwalk_flags)
1533{
1534	struct xfs_icwalk	icw = {0};
1535	bool			do_work = false;
1536
1537	if (!udqp && !gdqp && !pdqp)
1538		return 0;
1539
1540	/*
1541	 * Run a scan to free blocks using the union filter to cover all
1542	 * applicable quotas in a single scan.
1543	 */
1544	icw.icw_flags = XFS_ICWALK_FLAG_UNION | iwalk_flags;
1545
1546	if (XFS_IS_UQUOTA_ENFORCED(mp) && udqp && xfs_dquot_lowsp(udqp)) {
1547		icw.icw_uid = make_kuid(mp->m_super->s_user_ns, udqp->q_id);
1548		icw.icw_flags |= XFS_ICWALK_FLAG_UID;
1549		do_work = true;
1550	}
1551
1552	if (XFS_IS_UQUOTA_ENFORCED(mp) && gdqp && xfs_dquot_lowsp(gdqp)) {
1553		icw.icw_gid = make_kgid(mp->m_super->s_user_ns, gdqp->q_id);
1554		icw.icw_flags |= XFS_ICWALK_FLAG_GID;
1555		do_work = true;
1556	}
1557
1558	if (XFS_IS_PQUOTA_ENFORCED(mp) && pdqp && xfs_dquot_lowsp(pdqp)) {
1559		icw.icw_prid = pdqp->q_id;
1560		icw.icw_flags |= XFS_ICWALK_FLAG_PRID;
1561		do_work = true;
1562	}
1563
1564	if (!do_work)
1565		return 0;
1566
1567	return xfs_blockgc_free_space(mp, &icw);
1568}
1569
1570/* Run cow/eofblocks scans on the quotas attached to the inode. */
1571int
1572xfs_blockgc_free_quota(
1573	struct xfs_inode	*ip,
1574	unsigned int		iwalk_flags)
1575{
1576	return xfs_blockgc_free_dquots(ip->i_mount,
1577			xfs_inode_dquot(ip, XFS_DQTYPE_USER),
1578			xfs_inode_dquot(ip, XFS_DQTYPE_GROUP),
1579			xfs_inode_dquot(ip, XFS_DQTYPE_PROJ), iwalk_flags);
1580}
1581
1582/* XFS Inode Cache Walking Code */
1583
1584/*
1585 * The inode lookup is done in batches to keep the amount of lock traffic and
1586 * radix tree lookups to a minimum. The batch size is a trade off between
1587 * lookup reduction and stack usage. This is in the reclaim path, so we can't
1588 * be too greedy.
1589 */
1590#define XFS_LOOKUP_BATCH	32
1591
1592
1593/*
1594 * Decide if we want to grab this inode in anticipation of doing work towards
1595 * the goal.
1596 */
1597static inline bool
1598xfs_icwalk_igrab(
1599	enum xfs_icwalk_goal	goal,
1600	struct xfs_inode	*ip,
1601	struct xfs_icwalk	*icw)
1602{
1603	switch (goal) {
1604	case XFS_ICWALK_BLOCKGC:
1605		return xfs_blockgc_igrab(ip);
1606	case XFS_ICWALK_RECLAIM:
1607		return xfs_reclaim_igrab(ip, icw);
1608	default:
1609		return false;
1610	}
1611}
1612
1613/*
1614 * Process an inode.  Each processing function must handle any state changes
1615 * made by the icwalk igrab function.  Return -EAGAIN to skip an inode.
1616 */
1617static inline int
1618xfs_icwalk_process_inode(
1619	enum xfs_icwalk_goal	goal,
1620	struct xfs_inode	*ip,
1621	struct xfs_perag	*pag,
1622	struct xfs_icwalk	*icw)
1623{
1624	int			error = 0;
1625
1626	switch (goal) {
1627	case XFS_ICWALK_BLOCKGC:
1628		error = xfs_blockgc_scan_inode(ip, icw);
1629		break;
1630	case XFS_ICWALK_RECLAIM:
1631		xfs_reclaim_inode(ip, pag);
1632		break;
1633	}
1634	return error;
1635}
1636
1637/*
1638 * For a given per-AG structure @pag and a goal, grab qualifying inodes and
1639 * process them in some manner.
1640 */
1641static int
1642xfs_icwalk_ag(
1643	struct xfs_perag	*pag,
1644	enum xfs_icwalk_goal	goal,
1645	struct xfs_icwalk	*icw)
1646{
1647	struct xfs_mount	*mp = pag->pag_mount;
1648	uint32_t		first_index;
1649	int			last_error = 0;
1650	int			skipped;
1651	bool			done;
1652	int			nr_found;
1653
1654restart:
1655	done = false;
1656	skipped = 0;
1657	if (goal == XFS_ICWALK_RECLAIM)
1658		first_index = READ_ONCE(pag->pag_ici_reclaim_cursor);
1659	else
1660		first_index = 0;
1661	nr_found = 0;
1662	do {
1663		struct xfs_inode *batch[XFS_LOOKUP_BATCH];
1664		int		error = 0;
1665		int		i;
1666
1667		rcu_read_lock();
1668
1669		nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
1670				(void **) batch, first_index,
1671				XFS_LOOKUP_BATCH, goal);
1672		if (!nr_found) {
1673			done = true;
1674			rcu_read_unlock();
1675			break;
1676		}
1677
1678		/*
1679		 * Grab the inodes before we drop the lock. if we found
1680		 * nothing, nr == 0 and the loop will be skipped.
1681		 */
1682		for (i = 0; i < nr_found; i++) {
1683			struct xfs_inode *ip = batch[i];
1684
1685			if (done || !xfs_icwalk_igrab(goal, ip, icw))
1686				batch[i] = NULL;
1687
1688			/*
1689			 * Update the index for the next lookup. Catch
1690			 * overflows into the next AG range which can occur if
1691			 * we have inodes in the last block of the AG and we
1692			 * are currently pointing to the last inode.
1693			 *
1694			 * Because we may see inodes that are from the wrong AG
1695			 * due to RCU freeing and reallocation, only update the
1696			 * index if it lies in this AG. It was a race that lead
1697			 * us to see this inode, so another lookup from the
1698			 * same index will not find it again.
1699			 */
1700			if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
1701				continue;
1702			first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
1703			if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
1704				done = true;
1705		}
1706
1707		/* unlock now we've grabbed the inodes. */
1708		rcu_read_unlock();
1709
1710		for (i = 0; i < nr_found; i++) {
1711			if (!batch[i])
1712				continue;
1713			error = xfs_icwalk_process_inode(goal, batch[i], pag,
1714					icw);
1715			if (error == -EAGAIN) {
1716				skipped++;
1717				continue;
1718			}
1719			if (error && last_error != -EFSCORRUPTED)
1720				last_error = error;
1721		}
1722
1723		/* bail out if the filesystem is corrupted.  */
1724		if (error == -EFSCORRUPTED)
1725			break;
1726
1727		cond_resched();
1728
1729		if (icw && (icw->icw_flags & XFS_ICWALK_FLAG_SCAN_LIMIT)) {
1730			icw->icw_scan_limit -= XFS_LOOKUP_BATCH;
1731			if (icw->icw_scan_limit <= 0)
1732				break;
1733		}
1734	} while (nr_found && !done);
1735
1736	if (goal == XFS_ICWALK_RECLAIM) {
1737		if (done)
1738			first_index = 0;
1739		WRITE_ONCE(pag->pag_ici_reclaim_cursor, first_index);
1740	}
1741
1742	if (skipped) {
1743		delay(1);
1744		goto restart;
1745	}
1746	return last_error;
1747}
1748
1749/* Walk all incore inodes to achieve a given goal. */
1750static int
1751xfs_icwalk(
1752	struct xfs_mount	*mp,
1753	enum xfs_icwalk_goal	goal,
1754	struct xfs_icwalk	*icw)
1755{
1756	struct xfs_perag	*pag;
1757	int			error = 0;
1758	int			last_error = 0;
1759	xfs_agnumber_t		agno;
1760
1761	for_each_perag_tag(mp, agno, pag, goal) {
1762		error = xfs_icwalk_ag(pag, goal, icw);
1763		if (error) {
1764			last_error = error;
1765			if (error == -EFSCORRUPTED) {
1766				xfs_perag_rele(pag);
1767				break;
1768			}
1769		}
1770	}
1771	return last_error;
1772	BUILD_BUG_ON(XFS_ICWALK_PRIVATE_FLAGS & XFS_ICWALK_FLAGS_VALID);
1773}
1774
1775#ifdef DEBUG
1776static void
1777xfs_check_delalloc(
1778	struct xfs_inode	*ip,
1779	int			whichfork)
1780{
1781	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
1782	struct xfs_bmbt_irec	got;
1783	struct xfs_iext_cursor	icur;
1784
1785	if (!ifp || !xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got))
1786		return;
1787	do {
1788		if (isnullstartblock(got.br_startblock)) {
1789			xfs_warn(ip->i_mount,
1790	"ino %llx %s fork has delalloc extent at [0x%llx:0x%llx]",
1791				ip->i_ino,
1792				whichfork == XFS_DATA_FORK ? "data" : "cow",
1793				got.br_startoff, got.br_blockcount);
1794		}
1795	} while (xfs_iext_next_extent(ifp, &icur, &got));
1796}
1797#else
1798#define xfs_check_delalloc(ip, whichfork)	do { } while (0)
1799#endif
1800
1801/* Schedule the inode for reclaim. */
1802static void
1803xfs_inodegc_set_reclaimable(
1804	struct xfs_inode	*ip)
1805{
1806	struct xfs_mount	*mp = ip->i_mount;
1807	struct xfs_perag	*pag;
1808
1809	if (!xfs_is_shutdown(mp) && ip->i_delayed_blks) {
1810		xfs_check_delalloc(ip, XFS_DATA_FORK);
1811		xfs_check_delalloc(ip, XFS_COW_FORK);
1812		ASSERT(0);
1813	}
1814
1815	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1816	spin_lock(&pag->pag_ici_lock);
1817	spin_lock(&ip->i_flags_lock);
1818
1819	trace_xfs_inode_set_reclaimable(ip);
1820	ip->i_flags &= ~(XFS_NEED_INACTIVE | XFS_INACTIVATING);
1821	ip->i_flags |= XFS_IRECLAIMABLE;
1822	xfs_perag_set_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
1823			XFS_ICI_RECLAIM_TAG);
1824
1825	spin_unlock(&ip->i_flags_lock);
1826	spin_unlock(&pag->pag_ici_lock);
1827	xfs_perag_put(pag);
1828}
1829
1830/*
1831 * Free all speculative preallocations and possibly even the inode itself.
1832 * This is the last chance to make changes to an otherwise unreferenced file
1833 * before incore reclamation happens.
1834 */
1835static int
1836xfs_inodegc_inactivate(
1837	struct xfs_inode	*ip)
1838{
1839	int			error;
1840
1841	trace_xfs_inode_inactivating(ip);
1842	error = xfs_inactive(ip);
1843	xfs_inodegc_set_reclaimable(ip);
1844	return error;
1845
1846}
1847
1848void
1849xfs_inodegc_worker(
1850	struct work_struct	*work)
1851{
1852	struct xfs_inodegc	*gc = container_of(to_delayed_work(work),
1853						struct xfs_inodegc, work);
1854	struct llist_node	*node = llist_del_all(&gc->list);
1855	struct xfs_inode	*ip, *n;
1856	struct xfs_mount	*mp = gc->mp;
1857	unsigned int		nofs_flag;
1858
1859	/*
1860	 * Clear the cpu mask bit and ensure that we have seen the latest
1861	 * update of the gc structure associated with this CPU. This matches
1862	 * with the release semantics used when setting the cpumask bit in
1863	 * xfs_inodegc_queue.
1864	 */
1865	cpumask_clear_cpu(gc->cpu, &mp->m_inodegc_cpumask);
1866	smp_mb__after_atomic();
1867
1868	WRITE_ONCE(gc->items, 0);
1869
1870	if (!node)
1871		return;
1872
1873	/*
1874	 * We can allocate memory here while doing writeback on behalf of
1875	 * memory reclaim.  To avoid memory allocation deadlocks set the
1876	 * task-wide nofs context for the following operations.
1877	 */
1878	nofs_flag = memalloc_nofs_save();
1879
1880	ip = llist_entry(node, struct xfs_inode, i_gclist);
1881	trace_xfs_inodegc_worker(mp, READ_ONCE(gc->shrinker_hits));
1882
1883	WRITE_ONCE(gc->shrinker_hits, 0);
1884	llist_for_each_entry_safe(ip, n, node, i_gclist) {
1885		int	error;
1886
1887		xfs_iflags_set(ip, XFS_INACTIVATING);
1888		error = xfs_inodegc_inactivate(ip);
1889		if (error && !gc->error)
1890			gc->error = error;
1891	}
1892
1893	memalloc_nofs_restore(nofs_flag);
1894}
1895
1896/*
1897 * Expedite all pending inodegc work to run immediately. This does not wait for
1898 * completion of the work.
1899 */
1900void
1901xfs_inodegc_push(
1902	struct xfs_mount	*mp)
1903{
1904	if (!xfs_is_inodegc_enabled(mp))
1905		return;
1906	trace_xfs_inodegc_push(mp, __return_address);
1907	xfs_inodegc_queue_all(mp);
1908}
1909
1910/*
1911 * Force all currently queued inode inactivation work to run immediately and
1912 * wait for the work to finish.
1913 */
1914int
1915xfs_inodegc_flush(
1916	struct xfs_mount	*mp)
1917{
1918	xfs_inodegc_push(mp);
1919	trace_xfs_inodegc_flush(mp, __return_address);
1920	return xfs_inodegc_wait_all(mp);
1921}
1922
1923/*
1924 * Flush all the pending work and then disable the inode inactivation background
1925 * workers and wait for them to stop.  Caller must hold sb->s_umount to
1926 * coordinate changes in the inodegc_enabled state.
1927 */
1928void
1929xfs_inodegc_stop(
1930	struct xfs_mount	*mp)
1931{
1932	bool			rerun;
1933
1934	if (!xfs_clear_inodegc_enabled(mp))
1935		return;
1936
1937	/*
1938	 * Drain all pending inodegc work, including inodes that could be
1939	 * queued by racing xfs_inodegc_queue or xfs_inodegc_shrinker_scan
1940	 * threads that sample the inodegc state just prior to us clearing it.
1941	 * The inodegc flag state prevents new threads from queuing more
1942	 * inodes, so we queue pending work items and flush the workqueue until
1943	 * all inodegc lists are empty.  IOWs, we cannot use drain_workqueue
1944	 * here because it does not allow other unserialized mechanisms to
1945	 * reschedule inodegc work while this draining is in progress.
1946	 */
1947	xfs_inodegc_queue_all(mp);
1948	do {
1949		flush_workqueue(mp->m_inodegc_wq);
1950		rerun = xfs_inodegc_queue_all(mp);
1951	} while (rerun);
1952
1953	trace_xfs_inodegc_stop(mp, __return_address);
1954}
1955
1956/*
1957 * Enable the inode inactivation background workers and schedule deferred inode
1958 * inactivation work if there is any.  Caller must hold sb->s_umount to
1959 * coordinate changes in the inodegc_enabled state.
1960 */
1961void
1962xfs_inodegc_start(
1963	struct xfs_mount	*mp)
1964{
1965	if (xfs_set_inodegc_enabled(mp))
1966		return;
1967
1968	trace_xfs_inodegc_start(mp, __return_address);
1969	xfs_inodegc_queue_all(mp);
1970}
1971
1972#ifdef CONFIG_XFS_RT
1973static inline bool
1974xfs_inodegc_want_queue_rt_file(
1975	struct xfs_inode	*ip)
1976{
1977	struct xfs_mount	*mp = ip->i_mount;
1978
1979	if (!XFS_IS_REALTIME_INODE(ip))
1980		return false;
1981
1982	if (__percpu_counter_compare(&mp->m_frextents,
1983				mp->m_low_rtexts[XFS_LOWSP_5_PCNT],
1984				XFS_FDBLOCKS_BATCH) < 0)
1985		return true;
1986
1987	return false;
1988}
1989#else
1990# define xfs_inodegc_want_queue_rt_file(ip)	(false)
1991#endif /* CONFIG_XFS_RT */
1992
1993/*
1994 * Schedule the inactivation worker when:
1995 *
1996 *  - We've accumulated more than one inode cluster buffer's worth of inodes.
1997 *  - There is less than 5% free space left.
1998 *  - Any of the quotas for this inode are near an enforcement limit.
1999 */
2000static inline bool
2001xfs_inodegc_want_queue_work(
2002	struct xfs_inode	*ip,
2003	unsigned int		items)
2004{
2005	struct xfs_mount	*mp = ip->i_mount;
2006
2007	if (items > mp->m_ino_geo.inodes_per_cluster)
2008		return true;
2009
2010	if (__percpu_counter_compare(&mp->m_fdblocks,
2011				mp->m_low_space[XFS_LOWSP_5_PCNT],
2012				XFS_FDBLOCKS_BATCH) < 0)
2013		return true;
2014
2015	if (xfs_inodegc_want_queue_rt_file(ip))
2016		return true;
2017
2018	if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_USER))
2019		return true;
2020
2021	if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_GROUP))
2022		return true;
2023
2024	if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_PROJ))
2025		return true;
2026
2027	return false;
2028}
2029
2030/*
2031 * Upper bound on the number of inodes in each AG that can be queued for
2032 * inactivation at any given time, to avoid monopolizing the workqueue.
2033 */
2034#define XFS_INODEGC_MAX_BACKLOG		(4 * XFS_INODES_PER_CHUNK)
2035
2036/*
2037 * Make the frontend wait for inactivations when:
2038 *
2039 *  - Memory shrinkers queued the inactivation worker and it hasn't finished.
2040 *  - The queue depth exceeds the maximum allowable percpu backlog.
2041 *
2042 * Note: If we are in a NOFS context here (e.g. current thread is running a
2043 * transaction) the we don't want to block here as inodegc progress may require
2044 * filesystem resources we hold to make progress and that could result in a
2045 * deadlock. Hence we skip out of here if we are in a scoped NOFS context.
2046 */
2047static inline bool
2048xfs_inodegc_want_flush_work(
2049	struct xfs_inode	*ip,
2050	unsigned int		items,
2051	unsigned int		shrinker_hits)
2052{
2053	if (current->flags & PF_MEMALLOC_NOFS)
2054		return false;
2055
2056	if (shrinker_hits > 0)
2057		return true;
2058
2059	if (items > XFS_INODEGC_MAX_BACKLOG)
2060		return true;
2061
2062	return false;
2063}
2064
2065/*
2066 * Queue a background inactivation worker if there are inodes that need to be
2067 * inactivated and higher level xfs code hasn't disabled the background
2068 * workers.
2069 */
2070static void
2071xfs_inodegc_queue(
2072	struct xfs_inode	*ip)
2073{
2074	struct xfs_mount	*mp = ip->i_mount;
2075	struct xfs_inodegc	*gc;
2076	int			items;
2077	unsigned int		shrinker_hits;
2078	unsigned int		cpu_nr;
2079	unsigned long		queue_delay = 1;
2080
2081	trace_xfs_inode_set_need_inactive(ip);
2082	spin_lock(&ip->i_flags_lock);
2083	ip->i_flags |= XFS_NEED_INACTIVE;
2084	spin_unlock(&ip->i_flags_lock);
2085
2086	cpu_nr = get_cpu();
2087	gc = this_cpu_ptr(mp->m_inodegc);
2088	llist_add(&ip->i_gclist, &gc->list);
2089	items = READ_ONCE(gc->items);
2090	WRITE_ONCE(gc->items, items + 1);
2091	shrinker_hits = READ_ONCE(gc->shrinker_hits);
2092
2093	/*
2094	 * Ensure the list add is always seen by anyone who finds the cpumask
2095	 * bit set. This effectively gives the cpumask bit set operation
2096	 * release ordering semantics.
2097	 */
2098	smp_mb__before_atomic();
2099	if (!cpumask_test_cpu(cpu_nr, &mp->m_inodegc_cpumask))
2100		cpumask_test_and_set_cpu(cpu_nr, &mp->m_inodegc_cpumask);
2101
2102	/*
2103	 * We queue the work while holding the current CPU so that the work
2104	 * is scheduled to run on this CPU.
2105	 */
2106	if (!xfs_is_inodegc_enabled(mp)) {
2107		put_cpu();
2108		return;
2109	}
2110
2111	if (xfs_inodegc_want_queue_work(ip, items))
2112		queue_delay = 0;
2113
2114	trace_xfs_inodegc_queue(mp, __return_address);
2115	mod_delayed_work_on(current_cpu(), mp->m_inodegc_wq, &gc->work,
2116			queue_delay);
2117	put_cpu();
2118
2119	if (xfs_inodegc_want_flush_work(ip, items, shrinker_hits)) {
2120		trace_xfs_inodegc_throttle(mp, __return_address);
2121		flush_delayed_work(&gc->work);
2122	}
2123}
2124
2125/*
2126 * We set the inode flag atomically with the radix tree tag.  Once we get tag
2127 * lookups on the radix tree, this inode flag can go away.
2128 *
2129 * We always use background reclaim here because even if the inode is clean, it
2130 * still may be under IO and hence we have wait for IO completion to occur
2131 * before we can reclaim the inode. The background reclaim path handles this
2132 * more efficiently than we can here, so simply let background reclaim tear down
2133 * all inodes.
2134 */
2135void
2136xfs_inode_mark_reclaimable(
2137	struct xfs_inode	*ip)
2138{
2139	struct xfs_mount	*mp = ip->i_mount;
2140	bool			need_inactive;
2141
2142	XFS_STATS_INC(mp, vn_reclaim);
2143
2144	/*
2145	 * We should never get here with any of the reclaim flags already set.
2146	 */
2147	ASSERT_ALWAYS(!xfs_iflags_test(ip, XFS_ALL_IRECLAIM_FLAGS));
2148
2149	need_inactive = xfs_inode_needs_inactive(ip);
2150	if (need_inactive) {
2151		xfs_inodegc_queue(ip);
2152		return;
2153	}
2154
2155	/* Going straight to reclaim, so drop the dquots. */
2156	xfs_qm_dqdetach(ip);
2157	xfs_inodegc_set_reclaimable(ip);
2158}
2159
2160/*
2161 * Register a phony shrinker so that we can run background inodegc sooner when
2162 * there's memory pressure.  Inactivation does not itself free any memory but
2163 * it does make inodes reclaimable, which eventually frees memory.
2164 *
2165 * The count function, seek value, and batch value are crafted to trigger the
2166 * scan function during the second round of scanning.  Hopefully this means
2167 * that we reclaimed enough memory that initiating metadata transactions won't
2168 * make things worse.
2169 */
2170#define XFS_INODEGC_SHRINKER_COUNT	(1UL << DEF_PRIORITY)
2171#define XFS_INODEGC_SHRINKER_BATCH	((XFS_INODEGC_SHRINKER_COUNT / 2) + 1)
2172
2173static unsigned long
2174xfs_inodegc_shrinker_count(
2175	struct shrinker		*shrink,
2176	struct shrink_control	*sc)
2177{
2178	struct xfs_mount	*mp = shrink->private_data;
2179	struct xfs_inodegc	*gc;
2180	int			cpu;
2181
2182	if (!xfs_is_inodegc_enabled(mp))
2183		return 0;
2184
2185	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
2186		gc = per_cpu_ptr(mp->m_inodegc, cpu);
2187		if (!llist_empty(&gc->list))
2188			return XFS_INODEGC_SHRINKER_COUNT;
2189	}
2190
2191	return 0;
2192}
2193
2194static unsigned long
2195xfs_inodegc_shrinker_scan(
2196	struct shrinker		*shrink,
2197	struct shrink_control	*sc)
2198{
2199	struct xfs_mount	*mp = shrink->private_data;
2200	struct xfs_inodegc	*gc;
2201	int			cpu;
2202	bool			no_items = true;
2203
2204	if (!xfs_is_inodegc_enabled(mp))
2205		return SHRINK_STOP;
2206
2207	trace_xfs_inodegc_shrinker_scan(mp, sc, __return_address);
2208
2209	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
2210		gc = per_cpu_ptr(mp->m_inodegc, cpu);
2211		if (!llist_empty(&gc->list)) {
2212			unsigned int	h = READ_ONCE(gc->shrinker_hits);
2213
2214			WRITE_ONCE(gc->shrinker_hits, h + 1);
2215			mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
2216			no_items = false;
2217		}
2218	}
2219
2220	/*
2221	 * If there are no inodes to inactivate, we don't want the shrinker
2222	 * to think there's deferred work to call us back about.
2223	 */
2224	if (no_items)
2225		return LONG_MAX;
2226
2227	return SHRINK_STOP;
2228}
2229
2230/* Register a shrinker so we can accelerate inodegc and throttle queuing. */
2231int
2232xfs_inodegc_register_shrinker(
2233	struct xfs_mount	*mp)
2234{
2235	mp->m_inodegc_shrinker = shrinker_alloc(SHRINKER_NONSLAB,
2236						"xfs-inodegc:%s",
2237						mp->m_super->s_id);
2238	if (!mp->m_inodegc_shrinker)
2239		return -ENOMEM;
2240
2241	mp->m_inodegc_shrinker->count_objects = xfs_inodegc_shrinker_count;
2242	mp->m_inodegc_shrinker->scan_objects = xfs_inodegc_shrinker_scan;
2243	mp->m_inodegc_shrinker->seeks = 0;
2244	mp->m_inodegc_shrinker->batch = XFS_INODEGC_SHRINKER_BATCH;
2245	mp->m_inodegc_shrinker->private_data = mp;
2246
2247	shrinker_register(mp->m_inodegc_shrinker);
2248
2249	return 0;
2250}