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#include "xfs_da_format.h"
  29#include "xfs_dir2.h"
  30#include "xfs_metafile.h"
  31
  32#include <linux/iversion.h>
  33
  34/* Radix tree tags for incore inode tree. */
  35
  36/* inode is to be reclaimed */
  37#define XFS_ICI_RECLAIM_TAG	0
  38/* Inode has speculative preallocations (posteof or cow) to clean. */
  39#define XFS_ICI_BLOCKGC_TAG	1
  40
  41/*
  42 * The goal for walking incore inodes.  These can correspond with incore inode
  43 * radix tree tags when convenient.  Avoid existing XFS_IWALK namespace.
  44 */
  45enum xfs_icwalk_goal {
  46	/* Goals directly associated with tagged inodes. */
  47	XFS_ICWALK_BLOCKGC	= XFS_ICI_BLOCKGC_TAG,
  48	XFS_ICWALK_RECLAIM	= XFS_ICI_RECLAIM_TAG,
  49};
  50
  51static int xfs_icwalk(struct xfs_mount *mp,
  52		enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
  53static int xfs_icwalk_ag(struct xfs_perag *pag,
  54		enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
  55
  56/*
  57 * Private inode cache walk flags for struct xfs_icwalk.  Must not
  58 * coincide with XFS_ICWALK_FLAGS_VALID.
  59 */
  60
  61/* Stop scanning after icw_scan_limit inodes. */
  62#define XFS_ICWALK_FLAG_SCAN_LIMIT	(1U << 28)
  63
  64#define XFS_ICWALK_FLAG_RECLAIM_SICK	(1U << 27)
  65#define XFS_ICWALK_FLAG_UNION		(1U << 26) /* union filter algorithm */
  66
  67#define XFS_ICWALK_PRIVATE_FLAGS	(XFS_ICWALK_FLAG_SCAN_LIMIT | \
  68					 XFS_ICWALK_FLAG_RECLAIM_SICK | \
  69					 XFS_ICWALK_FLAG_UNION)
  70
  71/* Marks for the perag xarray */
  72#define XFS_PERAG_RECLAIM_MARK	XA_MARK_0
  73#define XFS_PERAG_BLOCKGC_MARK	XA_MARK_1
  74
  75static inline xa_mark_t ici_tag_to_mark(unsigned int tag)
  76{
  77	if (tag == XFS_ICI_RECLAIM_TAG)
  78		return XFS_PERAG_RECLAIM_MARK;
  79	ASSERT(tag == XFS_ICI_BLOCKGC_TAG);
  80	return XFS_PERAG_BLOCKGC_MARK;
  81}
  82
  83/*
  84 * Allocate and initialise an xfs_inode.
  85 */
  86struct xfs_inode *
  87xfs_inode_alloc(
  88	struct xfs_mount	*mp,
  89	xfs_ino_t		ino)
  90{
  91	struct xfs_inode	*ip;
  92
  93	/*
  94	 * XXX: If this didn't occur in transactions, we could drop GFP_NOFAIL
  95	 * and return NULL here on ENOMEM.
 
  96	 */
  97	ip = alloc_inode_sb(mp->m_super, xfs_inode_cache, GFP_KERNEL | __GFP_NOFAIL);
  98
 
  99	if (inode_init_always(mp->m_super, VFS_I(ip))) {
 100		kmem_cache_free(xfs_inode_cache, ip);
 101		return NULL;
 102	}
 103
 104	/* VFS doesn't initialise i_mode! */
 105	VFS_I(ip)->i_mode = 0;
 106	mapping_set_folio_min_order(VFS_I(ip)->i_mapping,
 107				    M_IGEO(mp)->min_folio_order);
 108
 109	XFS_STATS_INC(mp, vn_active);
 110	ASSERT(atomic_read(&ip->i_pincount) == 0);
 
 
 111	ASSERT(ip->i_ino == 0);
 112
 113	/* initialise the xfs inode */
 114	ip->i_ino = ino;
 115	ip->i_mount = mp;
 116	memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
 
 117	ip->i_cowfp = NULL;
 118	memset(&ip->i_af, 0, sizeof(ip->i_af));
 119	ip->i_af.if_format = XFS_DINODE_FMT_EXTENTS;
 120	memset(&ip->i_df, 0, sizeof(ip->i_df));
 121	ip->i_flags = 0;
 122	ip->i_delayed_blks = 0;
 123	ip->i_diflags2 = mp->m_ino_geo.new_diflags2;
 124	ip->i_nblocks = 0;
 125	ip->i_forkoff = 0;
 126	ip->i_sick = 0;
 127	ip->i_checked = 0;
 128	INIT_WORK(&ip->i_ioend_work, xfs_end_io);
 129	INIT_LIST_HEAD(&ip->i_ioend_list);
 130	spin_lock_init(&ip->i_ioend_lock);
 131	ip->i_next_unlinked = NULLAGINO;
 132	ip->i_prev_unlinked = 0;
 133
 134	return ip;
 135}
 136
 137STATIC void
 138xfs_inode_free_callback(
 139	struct rcu_head		*head)
 140{
 141	struct inode		*inode = container_of(head, struct inode, i_rcu);
 142	struct xfs_inode	*ip = XFS_I(inode);
 143
 144	switch (VFS_I(ip)->i_mode & S_IFMT) {
 145	case S_IFREG:
 146	case S_IFDIR:
 147	case S_IFLNK:
 148		xfs_idestroy_fork(&ip->i_df);
 149		break;
 150	}
 151
 152	xfs_ifork_zap_attr(ip);
 
 
 
 153
 154	if (ip->i_cowfp) {
 155		xfs_idestroy_fork(ip->i_cowfp);
 156		kmem_cache_free(xfs_ifork_cache, ip->i_cowfp);
 157	}
 158	if (ip->i_itemp) {
 159		ASSERT(!test_bit(XFS_LI_IN_AIL,
 160				 &ip->i_itemp->ili_item.li_flags));
 161		xfs_inode_item_destroy(ip);
 162		ip->i_itemp = NULL;
 163	}
 164
 165	kmem_cache_free(xfs_inode_cache, ip);
 166}
 167
 168static void
 169__xfs_inode_free(
 170	struct xfs_inode	*ip)
 171{
 172	/* asserts to verify all state is correct here */
 173	ASSERT(atomic_read(&ip->i_pincount) == 0);
 174	ASSERT(!ip->i_itemp || list_empty(&ip->i_itemp->ili_item.li_bio_list));
 175	XFS_STATS_DEC(ip->i_mount, vn_active);
 176
 177	call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
 178}
 179
 180void
 181xfs_inode_free(
 182	struct xfs_inode	*ip)
 183{
 184	ASSERT(!xfs_iflags_test(ip, XFS_IFLUSHING));
 185
 186	/*
 187	 * Because we use RCU freeing we need to ensure the inode always
 188	 * appears to be reclaimed with an invalid inode number when in the
 189	 * free state. The ip->i_flags_lock provides the barrier against lookup
 190	 * races.
 191	 */
 192	spin_lock(&ip->i_flags_lock);
 193	ip->i_flags = XFS_IRECLAIM;
 194	ip->i_ino = 0;
 195	spin_unlock(&ip->i_flags_lock);
 196
 197	__xfs_inode_free(ip);
 198}
 199
 200/*
 201 * Queue background inode reclaim work if there are reclaimable inodes and there
 202 * isn't reclaim work already scheduled or in progress.
 
 
 
 203 */
 204static void
 205xfs_reclaim_work_queue(
 206	struct xfs_mount        *mp)
 207{
 208
 209	rcu_read_lock();
 210	if (xfs_group_marked(mp, XG_TYPE_AG, XFS_PERAG_RECLAIM_MARK)) {
 211		queue_delayed_work(mp->m_reclaim_workqueue, &mp->m_reclaim_work,
 212			msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
 213	}
 214	rcu_read_unlock();
 215}
 216
 217/*
 218 * Background scanning to trim preallocated space. This is queued based on the
 219 * 'speculative_prealloc_lifetime' tunable (5m by default).
 
 
 
 220 */
 221static inline void
 222xfs_blockgc_queue(
 223	struct xfs_perag	*pag)
 224{
 225	struct xfs_mount	*mp = pag_mount(pag);
 226
 227	if (!xfs_is_blockgc_enabled(mp))
 228		return;
 229
 230	rcu_read_lock();
 231	if (radix_tree_tagged(&pag->pag_ici_root, XFS_ICI_BLOCKGC_TAG))
 232		queue_delayed_work(mp->m_blockgc_wq, &pag->pag_blockgc_work,
 233				   msecs_to_jiffies(xfs_blockgc_secs * 1000));
 234	rcu_read_unlock();
 235}
 236
 237/* Set a tag on both the AG incore inode tree and the AG radix tree. */
 238static void
 239xfs_perag_set_inode_tag(
 240	struct xfs_perag	*pag,
 241	xfs_agino_t		agino,
 242	unsigned int		tag)
 243{
 244	bool			was_tagged;
 245
 246	lockdep_assert_held(&pag->pag_ici_lock);
 247
 248	was_tagged = radix_tree_tagged(&pag->pag_ici_root, tag);
 249	radix_tree_tag_set(&pag->pag_ici_root, agino, tag);
 250
 251	if (tag == XFS_ICI_RECLAIM_TAG)
 252		pag->pag_ici_reclaimable++;
 253
 254	if (was_tagged)
 255		return;
 256
 257	/* propagate the tag up into the pag xarray tree */
 258	xfs_group_set_mark(pag_group(pag), ici_tag_to_mark(tag));
 
 
 
 259
 260	/* start background work */
 261	switch (tag) {
 262	case XFS_ICI_RECLAIM_TAG:
 263		xfs_reclaim_work_queue(pag_mount(pag));
 264		break;
 265	case XFS_ICI_BLOCKGC_TAG:
 266		xfs_blockgc_queue(pag);
 267		break;
 268	}
 269
 270	trace_xfs_perag_set_inode_tag(pag, _RET_IP_);
 271}
 272
 273/* Clear a tag on both the AG incore inode tree and the AG radix tree. */
 274static void
 275xfs_perag_clear_inode_tag(
 276	struct xfs_perag	*pag,
 277	xfs_agino_t		agino,
 278	unsigned int		tag)
 279{
 280	lockdep_assert_held(&pag->pag_ici_lock);
 281
 282	/*
 283	 * Reclaim can signal (with a null agino) that it cleared its own tag
 284	 * by removing the inode from the radix tree.
 285	 */
 286	if (agino != NULLAGINO)
 287		radix_tree_tag_clear(&pag->pag_ici_root, agino, tag);
 288	else
 289		ASSERT(tag == XFS_ICI_RECLAIM_TAG);
 290
 291	if (tag == XFS_ICI_RECLAIM_TAG)
 292		pag->pag_ici_reclaimable--;
 293
 294	if (radix_tree_tagged(&pag->pag_ici_root, tag))
 295		return;
 296
 297	/* clear the tag from the pag xarray */
 298	xfs_group_clear_mark(pag_group(pag), ici_tag_to_mark(tag));
 299	trace_xfs_perag_clear_inode_tag(pag, _RET_IP_);
 
 
 
 300}
 301
 
 302/*
 303 * Find the next AG after @pag, or the first AG if @pag is NULL.
 
 
 304 */
 305static struct xfs_perag *
 306xfs_perag_grab_next_tag(
 307	struct xfs_mount	*mp,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 308	struct xfs_perag	*pag,
 309	int			tag)
 310{
 311	return to_perag(xfs_group_grab_next_mark(mp,
 312			pag ? pag_group(pag) : NULL,
 313			ici_tag_to_mark(tag), XG_TYPE_AG));
 
 314}
 315
 316/*
 317 * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
 318 * part of the structure. This is made more complex by the fact we store
 319 * information about the on-disk values in the VFS inode and so we can't just
 320 * overwrite the values unconditionally. Hence we save the parameters we
 321 * need to retain across reinitialisation, and rewrite them into the VFS inode
 322 * after reinitialisation even if it fails.
 323 */
 324static int
 325xfs_reinit_inode(
 326	struct xfs_mount	*mp,
 327	struct inode		*inode)
 328{
 329	int			error;
 330	uint32_t		nlink = inode->i_nlink;
 331	uint32_t		generation = inode->i_generation;
 332	uint64_t		version = inode_peek_iversion(inode);
 333	umode_t			mode = inode->i_mode;
 334	dev_t			dev = inode->i_rdev;
 335	kuid_t			uid = inode->i_uid;
 336	kgid_t			gid = inode->i_gid;
 337	unsigned long		state = inode->i_state;
 338
 339	error = inode_init_always(mp->m_super, inode);
 340
 341	set_nlink(inode, nlink);
 342	inode->i_generation = generation;
 343	inode_set_iversion_queried(inode, version);
 344	inode->i_mode = mode;
 345	inode->i_rdev = dev;
 346	inode->i_uid = uid;
 347	inode->i_gid = gid;
 348	inode->i_state = state;
 349	mapping_set_folio_min_order(inode->i_mapping,
 350				    M_IGEO(mp)->min_folio_order);
 351	return error;
 352}
 353
 354/*
 355 * Carefully nudge an inode whose VFS state has been torn down back into a
 356 * usable state.  Drops the i_flags_lock and the rcu read lock.
 357 */
 358static int
 359xfs_iget_recycle(
 360	struct xfs_perag	*pag,
 361	struct xfs_inode	*ip) __releases(&ip->i_flags_lock)
 362{
 363	struct xfs_mount	*mp = ip->i_mount;
 364	struct inode		*inode = VFS_I(ip);
 365	int			error;
 366
 367	trace_xfs_iget_recycle(ip);
 368
 369	if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
 370		return -EAGAIN;
 371
 372	/*
 373	 * We need to make it look like the inode is being reclaimed to prevent
 374	 * the actual reclaim workers from stomping over us while we recycle
 375	 * the inode.  We can't clear the radix tree tag yet as it requires
 376	 * pag_ici_lock to be held exclusive.
 377	 */
 378	ip->i_flags |= XFS_IRECLAIM;
 379
 380	spin_unlock(&ip->i_flags_lock);
 381	rcu_read_unlock();
 382
 383	ASSERT(!rwsem_is_locked(&inode->i_rwsem));
 384	error = xfs_reinit_inode(mp, inode);
 385	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 386	if (error) {
 387		/*
 388		 * Re-initializing the inode failed, and we are in deep
 389		 * trouble.  Try to re-add it to the reclaim list.
 390		 */
 391		rcu_read_lock();
 392		spin_lock(&ip->i_flags_lock);
 393		ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
 394		ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
 395		spin_unlock(&ip->i_flags_lock);
 396		rcu_read_unlock();
 397
 398		trace_xfs_iget_recycle_fail(ip);
 399		return error;
 400	}
 401
 402	spin_lock(&pag->pag_ici_lock);
 403	spin_lock(&ip->i_flags_lock);
 404
 405	/*
 406	 * Clear the per-lifetime state in the inode as we are now effectively
 407	 * a new inode and need to return to the initial state before reuse
 408	 * occurs.
 409	 */
 410	ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
 411	ip->i_flags |= XFS_INEW;
 412	xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
 413			XFS_ICI_RECLAIM_TAG);
 414	inode->i_state = I_NEW;
 415	spin_unlock(&ip->i_flags_lock);
 416	spin_unlock(&pag->pag_ici_lock);
 417
 418	return 0;
 419}
 420
 421/*
 422 * If we are allocating a new inode, then check what was returned is
 423 * actually a free, empty inode. If we are not allocating an inode,
 424 * then check we didn't find a free inode.
 425 *
 426 * Returns:
 427 *	0		if the inode free state matches the lookup context
 428 *	-ENOENT		if the inode is free and we are not allocating
 429 *	-EFSCORRUPTED	if there is any state mismatch at all
 430 */
 431static int
 432xfs_iget_check_free_state(
 433	struct xfs_inode	*ip,
 434	int			flags)
 435{
 436	if (flags & XFS_IGET_CREATE) {
 437		/* should be a free inode */
 438		if (VFS_I(ip)->i_mode != 0) {
 439			xfs_warn(ip->i_mount,
 440"Corruption detected! Free inode 0x%llx not marked free! (mode 0x%x)",
 441				ip->i_ino, VFS_I(ip)->i_mode);
 442			xfs_agno_mark_sick(ip->i_mount,
 443					XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
 444					XFS_SICK_AG_INOBT);
 445			return -EFSCORRUPTED;
 446		}
 447
 448		if (ip->i_nblocks != 0) {
 449			xfs_warn(ip->i_mount,
 450"Corruption detected! Free inode 0x%llx has blocks allocated!",
 451				ip->i_ino);
 452			xfs_agno_mark_sick(ip->i_mount,
 453					XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
 454					XFS_SICK_AG_INOBT);
 455			return -EFSCORRUPTED;
 456		}
 457		return 0;
 458	}
 459
 460	/* should be an allocated inode */
 461	if (VFS_I(ip)->i_mode == 0)
 462		return -ENOENT;
 463
 464	return 0;
 465}
 466
 467/* Make all pending inactivation work start immediately. */
 468static bool
 469xfs_inodegc_queue_all(
 470	struct xfs_mount	*mp)
 471{
 472	struct xfs_inodegc	*gc;
 473	int			cpu;
 474	bool			ret = false;
 475
 476	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
 477		gc = per_cpu_ptr(mp->m_inodegc, cpu);
 478		if (!llist_empty(&gc->list)) {
 479			mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
 480			ret = true;
 481		}
 482	}
 483
 484	return ret;
 485}
 486
 487/* Wait for all queued work and collect errors */
 488static int
 489xfs_inodegc_wait_all(
 490	struct xfs_mount	*mp)
 491{
 492	int			cpu;
 493	int			error = 0;
 494
 495	flush_workqueue(mp->m_inodegc_wq);
 496	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
 497		struct xfs_inodegc	*gc;
 498
 499		gc = per_cpu_ptr(mp->m_inodegc, cpu);
 500		if (gc->error && !error)
 501			error = gc->error;
 502		gc->error = 0;
 503	}
 504
 505	return error;
 506}
 507
 508/*
 509 * Check the validity of the inode we just found it the cache
 510 */
 511static int
 512xfs_iget_cache_hit(
 513	struct xfs_perag	*pag,
 514	struct xfs_inode	*ip,
 515	xfs_ino_t		ino,
 516	int			flags,
 517	int			lock_flags) __releases(RCU)
 518{
 519	struct inode		*inode = VFS_I(ip);
 520	struct xfs_mount	*mp = ip->i_mount;
 521	int			error;
 522
 523	/*
 524	 * check for re-use of an inode within an RCU grace period due to the
 525	 * radix tree nodes not being updated yet. We monitor for this by
 526	 * setting the inode number to zero before freeing the inode structure.
 527	 * If the inode has been reallocated and set up, then the inode number
 528	 * will not match, so check for that, too.
 529	 */
 530	spin_lock(&ip->i_flags_lock);
 531	if (ip->i_ino != ino)
 532		goto out_skip;
 
 
 
 
 
 533
 534	/*
 535	 * If we are racing with another cache hit that is currently
 536	 * instantiating this inode or currently recycling it out of
 537	 * reclaimable state, wait for the initialisation to complete
 538	 * before continuing.
 539	 *
 540	 * If we're racing with the inactivation worker we also want to wait.
 541	 * If we're creating a new file, it's possible that the worker
 542	 * previously marked the inode as free on disk but hasn't finished
 543	 * updating the incore state yet.  The AGI buffer will be dirty and
 544	 * locked to the icreate transaction, so a synchronous push of the
 545	 * inodegc workers would result in deadlock.  For a regular iget, the
 546	 * worker is running already, so we might as well wait.
 547	 *
 548	 * XXX(hch): eventually we should do something equivalent to
 549	 *	     wait_on_inode to wait for these flags to be cleared
 550	 *	     instead of polling for it.
 551	 */
 552	if (ip->i_flags & (XFS_INEW | XFS_IRECLAIM | XFS_INACTIVATING))
 553		goto out_skip;
 554
 555	if (ip->i_flags & XFS_NEED_INACTIVE) {
 556		/* Unlinked inodes cannot be re-grabbed. */
 557		if (VFS_I(ip)->i_nlink == 0) {
 558			error = -ENOENT;
 559			goto out_error;
 560		}
 561		goto out_inodegc_flush;
 562	}
 563
 564	/*
 565	 * Check the inode free state is valid. This also detects lookup
 566	 * racing with unlinks.
 567	 */
 568	error = xfs_iget_check_free_state(ip, flags);
 569	if (error)
 570		goto out_error;
 
 571
 572	/* Skip inodes that have no vfs state. */
 573	if ((flags & XFS_IGET_INCORE) &&
 574	    (ip->i_flags & XFS_IRECLAIMABLE))
 575		goto out_skip;
 576
 577	/* The inode fits the selection criteria; process it. */
 578	if (ip->i_flags & XFS_IRECLAIMABLE) {
 579		/* Drops i_flags_lock and RCU read lock. */
 580		error = xfs_iget_recycle(pag, ip);
 581		if (error == -EAGAIN)
 582			goto out_skip;
 583		if (error)
 584			return error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 585	} else {
 586		/* If the VFS inode is being torn down, pause and try again. */
 587		if (!igrab(inode))
 588			goto out_skip;
 
 
 
 589
 590		/* We've got a live one. */
 591		spin_unlock(&ip->i_flags_lock);
 592		rcu_read_unlock();
 593		trace_xfs_iget_hit(ip);
 594	}
 595
 596	if (lock_flags != 0)
 597		xfs_ilock(ip, lock_flags);
 598
 599	if (!(flags & XFS_IGET_INCORE))
 600		xfs_iflags_clear(ip, XFS_ISTALE);
 601	XFS_STATS_INC(mp, xs_ig_found);
 602
 603	return 0;
 604
 605out_skip:
 606	trace_xfs_iget_skip(ip);
 607	XFS_STATS_INC(mp, xs_ig_frecycle);
 608	error = -EAGAIN;
 609out_error:
 610	spin_unlock(&ip->i_flags_lock);
 611	rcu_read_unlock();
 612	return error;
 613
 614out_inodegc_flush:
 615	spin_unlock(&ip->i_flags_lock);
 616	rcu_read_unlock();
 617	/*
 618	 * Do not wait for the workers, because the caller could hold an AGI
 619	 * buffer lock.  We're just going to sleep in a loop anyway.
 620	 */
 621	if (xfs_is_inodegc_enabled(mp))
 622		xfs_inodegc_queue_all(mp);
 623	return -EAGAIN;
 624}
 625
 
 626static int
 627xfs_iget_cache_miss(
 628	struct xfs_mount	*mp,
 629	struct xfs_perag	*pag,
 630	xfs_trans_t		*tp,
 631	xfs_ino_t		ino,
 632	struct xfs_inode	**ipp,
 633	int			flags,
 634	int			lock_flags)
 635{
 636	struct xfs_inode	*ip;
 637	int			error;
 638	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ino);
 
 639
 640	ip = xfs_inode_alloc(mp, ino);
 641	if (!ip)
 642		return -ENOMEM;
 643
 644	error = xfs_imap(pag, tp, ip->i_ino, &ip->i_imap, flags);
 645	if (error)
 646		goto out_destroy;
 647
 648	/*
 649	 * For version 5 superblocks, if we are initialising a new inode and we
 650	 * are not utilising the XFS_FEAT_IKEEP inode cluster mode, we can
 651	 * simply build the new inode core with a random generation number.
 652	 *
 653	 * For version 4 (and older) superblocks, log recovery is dependent on
 654	 * the i_flushiter field being initialised from the current on-disk
 655	 * value and hence we must also read the inode off disk even when
 656	 * initializing new inodes.
 657	 */
 658	if (xfs_has_v3inodes(mp) &&
 659	    (flags & XFS_IGET_CREATE) && !xfs_has_ikeep(mp)) {
 660		VFS_I(ip)->i_generation = get_random_u32();
 661	} else {
 662		struct xfs_buf		*bp;
 663
 664		error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &bp);
 665		if (error)
 666			goto out_destroy;
 667
 668		error = xfs_inode_from_disk(ip,
 669				xfs_buf_offset(bp, ip->i_imap.im_boffset));
 670		if (!error)
 671			xfs_buf_set_ref(bp, XFS_INO_REF);
 672		else
 673			xfs_inode_mark_sick(ip, XFS_SICK_INO_CORE);
 674		xfs_trans_brelse(tp, bp);
 675
 676		if (error)
 677			goto out_destroy;
 678	}
 679
 680	trace_xfs_iget_miss(ip);
 681
 682	/*
 683	 * Check the inode free state is valid. This also detects lookup
 684	 * racing with unlinks.
 685	 */
 686	error = xfs_iget_check_free_state(ip, flags);
 687	if (error)
 688		goto out_destroy;
 
 689
 690	/*
 691	 * Preload the radix tree so we can insert safely under the
 692	 * write spinlock. Note that we cannot sleep inside the preload
 693	 * region.
 
 694	 */
 695	if (radix_tree_preload(GFP_KERNEL | __GFP_NOLOCKDEP)) {
 696		error = -EAGAIN;
 697		goto out_destroy;
 698	}
 699
 700	/*
 701	 * Because the inode hasn't been added to the radix-tree yet it can't
 702	 * be found by another thread, so we can do the non-sleeping lock here.
 703	 */
 704	if (lock_flags) {
 705		if (!xfs_ilock_nowait(ip, lock_flags))
 706			BUG();
 707	}
 708
 709	/*
 710	 * These values must be set before inserting the inode into the radix
 711	 * tree as the moment it is inserted a concurrent lookup (allowed by the
 712	 * RCU locking mechanism) can find it and that lookup must see that this
 713	 * is an inode currently under construction (i.e. that XFS_INEW is set).
 714	 * The ip->i_flags_lock that protects the XFS_INEW flag forms the
 715	 * memory barrier that ensures this detection works correctly at lookup
 716	 * time.
 717	 */
 
 718	if (flags & XFS_IGET_DONTCACHE)
 719		d_mark_dontcache(VFS_I(ip));
 720	ip->i_udquot = NULL;
 721	ip->i_gdquot = NULL;
 722	ip->i_pdquot = NULL;
 723	xfs_iflags_set(ip, XFS_INEW);
 724
 725	/* insert the new inode */
 726	spin_lock(&pag->pag_ici_lock);
 727	error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
 728	if (unlikely(error)) {
 729		WARN_ON(error != -EEXIST);
 730		XFS_STATS_INC(mp, xs_ig_dup);
 731		error = -EAGAIN;
 732		goto out_preload_end;
 733	}
 734	spin_unlock(&pag->pag_ici_lock);
 735	radix_tree_preload_end();
 736
 737	*ipp = ip;
 738	return 0;
 739
 740out_preload_end:
 741	spin_unlock(&pag->pag_ici_lock);
 742	radix_tree_preload_end();
 743	if (lock_flags)
 744		xfs_iunlock(ip, lock_flags);
 745out_destroy:
 746	__destroy_inode(VFS_I(ip));
 747	xfs_inode_free(ip);
 748	return error;
 749}
 750
 751/*
 752 * Look up an inode by number in the given file system.  The inode is looked up
 753 * in the cache held in each AG.  If the inode is found in the cache, initialise
 754 * the vfs inode if necessary.
 
 755 *
 756 * If it is not in core, read it in from the file system's device, add it to the
 757 * cache and initialise the vfs inode.
 758 *
 759 * The inode is locked according to the value of the lock_flags parameter.
 760 * Inode lookup is only done during metadata operations and not as part of the
 761 * data IO path. Hence we only allow locking of the XFS_ILOCK during lookup.
 
 
 
 
 
 
 
 
 
 762 */
 763int
 764xfs_iget(
 765	struct xfs_mount	*mp,
 766	struct xfs_trans	*tp,
 767	xfs_ino_t		ino,
 768	uint			flags,
 769	uint			lock_flags,
 770	struct xfs_inode	**ipp)
 771{
 772	struct xfs_inode	*ip;
 773	struct xfs_perag	*pag;
 774	xfs_agino_t		agino;
 775	int			error;
 776
 
 
 
 
 
 
 
 777	ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
 778
 779	/* reject inode numbers outside existing AGs */
 780	if (!xfs_verify_ino(mp, ino))
 781		return -EINVAL;
 782
 783	XFS_STATS_INC(mp, xs_ig_attempts);
 784
 785	/* get the perag structure and ensure that it's inode capable */
 786	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
 787	agino = XFS_INO_TO_AGINO(mp, ino);
 788
 789again:
 790	error = 0;
 791	rcu_read_lock();
 792	ip = radix_tree_lookup(&pag->pag_ici_root, agino);
 793
 794	if (ip) {
 795		error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
 796		if (error)
 797			goto out_error_or_again;
 798	} else {
 799		rcu_read_unlock();
 800		if (flags & XFS_IGET_INCORE) {
 801			error = -ENODATA;
 802			goto out_error_or_again;
 803		}
 804		XFS_STATS_INC(mp, xs_ig_missed);
 805
 806		error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
 807							flags, lock_flags);
 808		if (error)
 809			goto out_error_or_again;
 810	}
 811	xfs_perag_put(pag);
 812
 813	*ipp = ip;
 814
 815	/*
 816	 * If we have a real type for an on-disk inode, we can setup the inode
 817	 * now.	 If it's a new inode being created, xfs_init_new_inode will
 818	 * handle it.
 819	 */
 820	if (xfs_iflags_test(ip, XFS_INEW) && VFS_I(ip)->i_mode != 0)
 821		xfs_setup_existing_inode(ip);
 822	return 0;
 823
 824out_error_or_again:
 825	if (!(flags & (XFS_IGET_INCORE | XFS_IGET_NORETRY)) &&
 826	    error == -EAGAIN) {
 827		delay(1);
 828		goto again;
 829	}
 830	xfs_perag_put(pag);
 831	return error;
 832}
 833
 834/*
 835 * Get a metadata inode.
 836 *
 837 * The metafile type must match the file mode exactly, and for files in the
 838 * metadata directory tree, it must match the inode's metatype exactly.
 839 */
 840int
 841xfs_trans_metafile_iget(
 842	struct xfs_trans	*tp,
 843	xfs_ino_t		ino,
 844	enum xfs_metafile_type	metafile_type,
 845	struct xfs_inode	**ipp)
 846{
 847	struct xfs_mount	*mp = tp->t_mountp;
 848	struct xfs_inode	*ip;
 849	umode_t			mode;
 850	int			error;
 851
 852	error = xfs_iget(mp, tp, ino, 0, 0, &ip);
 853	if (error == -EFSCORRUPTED || error == -EINVAL)
 854		goto whine;
 855	if (error)
 856		return error;
 
 
 
 
 
 
 
 
 
 857
 858	if (VFS_I(ip)->i_nlink == 0)
 859		goto bad_rele;
 
 
 860
 861	if (metafile_type == XFS_METAFILE_DIR)
 862		mode = S_IFDIR;
 863	else
 864		mode = S_IFREG;
 865	if (inode_wrong_type(VFS_I(ip), mode))
 866		goto bad_rele;
 867	if (xfs_has_metadir(mp)) {
 868		if (!xfs_is_metadir_inode(ip))
 869			goto bad_rele;
 870		if (metafile_type != ip->i_metatype)
 871			goto bad_rele;
 872	}
 873
 874	*ipp = ip;
 
 
 
 
 875	return 0;
 876bad_rele:
 877	xfs_irele(ip);
 878whine:
 879	xfs_err(mp, "metadata inode 0x%llx type %u is corrupt", ino,
 880			metafile_type);
 881	xfs_fs_mark_sick(mp, XFS_SICK_FS_METADIR);
 882	return -EFSCORRUPTED;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 883}
 884
 885/* Grab a metadata file if the caller doesn't already have a transaction. */
 886int
 887xfs_metafile_iget(
 888	struct xfs_mount	*mp,
 889	xfs_ino_t		ino,
 890	enum xfs_metafile_type	metafile_type,
 891	struct xfs_inode	**ipp)
 
 892{
 893	struct xfs_trans	*tp;
 894	int			error;
 
 
 895
 896	error = xfs_trans_alloc_empty(mp, &tp);
 897	if (error)
 898		return error;
 
 
 
 
 
 
 
 
 
 
 899
 900	error = xfs_trans_metafile_iget(tp, ino, metafile_type, ipp);
 901	xfs_trans_cancel(tp);
 902	return error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 903}
 904
 905/*
 906 * Grab the inode for reclaim exclusively.
 907 *
 908 * We have found this inode via a lookup under RCU, so the inode may have
 909 * already been freed, or it may be in the process of being recycled by
 910 * xfs_iget(). In both cases, the inode will have XFS_IRECLAIM set. If the inode
 911 * has been fully recycled by the time we get the i_flags_lock, XFS_IRECLAIMABLE
 912 * will not be set. Hence we need to check for both these flag conditions to
 913 * avoid inodes that are no longer reclaim candidates.
 914 *
 915 * Note: checking for other state flags here, under the i_flags_lock or not, is
 916 * racy and should be avoided. Those races should be resolved only after we have
 917 * ensured that we are able to reclaim this inode and the world can see that we
 918 * are going to reclaim it.
 919 *
 920 * Return true if we grabbed it, false otherwise.
 921 */
 922static bool
 923xfs_reclaim_igrab(
 924	struct xfs_inode	*ip,
 925	struct xfs_icwalk	*icw)
 926{
 927	ASSERT(rcu_read_lock_held());
 928
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 929	spin_lock(&ip->i_flags_lock);
 930	if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
 931	    __xfs_iflags_test(ip, XFS_IRECLAIM)) {
 932		/* not a reclaim candidate. */
 933		spin_unlock(&ip->i_flags_lock);
 934		return false;
 935	}
 936
 937	/* Don't reclaim a sick inode unless the caller asked for it. */
 938	if (ip->i_sick &&
 939	    (!icw || !(icw->icw_flags & XFS_ICWALK_FLAG_RECLAIM_SICK))) {
 940		spin_unlock(&ip->i_flags_lock);
 941		return false;
 942	}
 943
 944	__xfs_iflags_set(ip, XFS_IRECLAIM);
 945	spin_unlock(&ip->i_flags_lock);
 946	return true;
 947}
 948
 949/*
 950 * Inode reclaim is non-blocking, so the default action if progress cannot be
 951 * made is to "requeue" the inode for reclaim by unlocking it and clearing the
 952 * XFS_IRECLAIM flag.  If we are in a shutdown state, we don't care about
 953 * blocking anymore and hence we can wait for the inode to be able to reclaim
 954 * it.
 
 
 
 
 
 
 
 
 
 
 
 955 *
 956 * We do no IO here - if callers require inodes to be cleaned they must push the
 957 * AIL first to trigger writeback of dirty inodes.  This enables writeback to be
 958 * done in the background in a non-blocking manner, and enables memory reclaim
 959 * to make progress without blocking.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 960 */
 961static void
 962xfs_reclaim_inode(
 963	struct xfs_inode	*ip,
 964	struct xfs_perag	*pag)
 
 965{
 
 966	xfs_ino_t		ino = ip->i_ino; /* for radix_tree_delete */
 
 967
 968	if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
 969		goto out;
 970	if (xfs_iflags_test_and_set(ip, XFS_IFLUSHING))
 971		goto out_iunlock;
 
 
 
 
 972
 973	/*
 974	 * Check for log shutdown because aborting the inode can move the log
 975	 * tail and corrupt in memory state. This is fine if the log is shut
 976	 * down, but if the log is still active and only the mount is shut down
 977	 * then the in-memory log tail movement caused by the abort can be
 978	 * incorrectly propagated to disk.
 979	 */
 980	if (xlog_is_shutdown(ip->i_mount->m_log)) {
 
 981		xfs_iunpin_wait(ip);
 982		xfs_iflush_shutdown_abort(ip);
 
 
 983		goto reclaim;
 984	}
 985	if (xfs_ipincount(ip))
 986		goto out_clear_flush;
 987	if (!xfs_inode_clean(ip))
 988		goto out_clear_flush;
 989
 990	xfs_iflags_clear(ip, XFS_IFLUSHING);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 991reclaim:
 992	trace_xfs_inode_reclaiming(ip);
 993
 994	/*
 995	 * Because we use RCU freeing we need to ensure the inode always appears
 996	 * to be reclaimed with an invalid inode number when in the free state.
 997	 * We do this as early as possible under the ILOCK so that
 998	 * xfs_iflush_cluster() and xfs_ifree_cluster() can be guaranteed to
 999	 * detect races with us here. By doing this, we guarantee that once
1000	 * xfs_iflush_cluster() or xfs_ifree_cluster() has locked XFS_ILOCK that
1001	 * it will see either a valid inode that will serialise correctly, or it
1002	 * will see an invalid inode that it can skip.
1003	 */
1004	spin_lock(&ip->i_flags_lock);
1005	ip->i_flags = XFS_IRECLAIM;
1006	ip->i_ino = 0;
1007	ip->i_sick = 0;
1008	ip->i_checked = 0;
1009	spin_unlock(&ip->i_flags_lock);
1010
1011	ASSERT(!ip->i_itemp || ip->i_itemp->ili_item.li_buf == NULL);
1012	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1013
1014	XFS_STATS_INC(ip->i_mount, xs_ig_reclaims);
1015	/*
1016	 * Remove the inode from the per-AG radix tree.
1017	 *
1018	 * Because radix_tree_delete won't complain even if the item was never
1019	 * added to the tree assert that it's been there before to catch
1020	 * problems with the inode life time early on.
1021	 */
1022	spin_lock(&pag->pag_ici_lock);
1023	if (!radix_tree_delete(&pag->pag_ici_root,
1024				XFS_INO_TO_AGINO(ip->i_mount, ino)))
1025		ASSERT(0);
1026	xfs_perag_clear_inode_tag(pag, NULLAGINO, XFS_ICI_RECLAIM_TAG);
1027	spin_unlock(&pag->pag_ici_lock);
1028
1029	/*
1030	 * Here we do an (almost) spurious inode lock in order to coordinate
1031	 * with inode cache radix tree lookups.  This is because the lookup
1032	 * can reference the inodes in the cache without taking references.
1033	 *
1034	 * We make that OK here by ensuring that we wait until the inode is
1035	 * unlocked after the lookup before we go ahead and free it.
1036	 */
1037	xfs_ilock(ip, XFS_ILOCK_EXCL);
1038	ASSERT(!ip->i_udquot && !ip->i_gdquot && !ip->i_pdquot);
1039	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1040	ASSERT(xfs_inode_clean(ip));
1041
1042	__xfs_inode_free(ip);
1043	return;
1044
1045out_clear_flush:
1046	xfs_iflags_clear(ip, XFS_IFLUSHING);
1047out_iunlock:
1048	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1049out:
1050	xfs_iflags_clear(ip, XFS_IRECLAIM);
 
 
 
 
 
 
 
 
 
1051}
1052
1053/* Reclaim sick inodes if we're unmounting or the fs went down. */
1054static inline bool
1055xfs_want_reclaim_sick(
1056	struct xfs_mount	*mp)
 
 
 
 
 
 
 
1057{
1058	return xfs_is_unmounting(mp) || xfs_has_norecovery(mp) ||
1059	       xfs_is_shutdown(mp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1060}
1061
1062void
1063xfs_reclaim_inodes(
1064	struct xfs_mount	*mp)
 
1065{
1066	struct xfs_icwalk	icw = {
1067		.icw_flags	= 0,
1068	};
1069
1070	if (xfs_want_reclaim_sick(mp))
1071		icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
1072
1073	while (xfs_group_marked(mp, XG_TYPE_AG, XFS_PERAG_RECLAIM_MARK)) {
1074		xfs_ail_push_all_sync(mp->m_ail);
1075		xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
1076	}
1077}
1078
1079/*
1080 * The shrinker infrastructure determines how many inodes we should scan for
1081 * reclaim. We want as many clean inodes ready to reclaim as possible, so we
1082 * push the AIL here. We also want to proactively free up memory if we can to
1083 * minimise the amount of work memory reclaim has to do so we kick the
1084 * background reclaim if it isn't already scheduled.
 
 
1085 */
1086long
1087xfs_reclaim_inodes_nr(
1088	struct xfs_mount	*mp,
1089	unsigned long		nr_to_scan)
1090{
1091	struct xfs_icwalk	icw = {
1092		.icw_flags	= XFS_ICWALK_FLAG_SCAN_LIMIT,
1093		.icw_scan_limit	= min_t(unsigned long, LONG_MAX, nr_to_scan),
1094	};
1095
1096	if (xfs_want_reclaim_sick(mp))
1097		icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
1098
1099	/* kick background reclaimer and push the AIL */
1100	xfs_reclaim_work_queue(mp);
1101	xfs_ail_push_all(mp->m_ail);
1102
1103	xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
1104	return 0;
1105}
1106
1107/*
1108 * Return the number of reclaimable inodes in the filesystem for
1109 * the shrinker to determine how much to reclaim.
1110 */
1111long
1112xfs_reclaim_inodes_count(
1113	struct xfs_mount	*mp)
1114{
1115	XA_STATE		(xas, &mp->m_groups[XG_TYPE_AG].xa, 0);
1116	long			reclaimable = 0;
1117	struct xfs_perag	*pag;
 
 
1118
1119	rcu_read_lock();
1120	xas_for_each_marked(&xas, pag, ULONG_MAX, XFS_PERAG_RECLAIM_MARK) {
1121		trace_xfs_reclaim_inodes_count(pag, _THIS_IP_);
1122		reclaimable += pag->pag_ici_reclaimable;
 
1123	}
1124	rcu_read_unlock();
1125
1126	return reclaimable;
1127}
1128
1129STATIC bool
1130xfs_icwalk_match_id(
1131	struct xfs_inode	*ip,
1132	struct xfs_icwalk	*icw)
1133{
1134	if ((icw->icw_flags & XFS_ICWALK_FLAG_UID) &&
1135	    !uid_eq(VFS_I(ip)->i_uid, icw->icw_uid))
1136		return false;
1137
1138	if ((icw->icw_flags & XFS_ICWALK_FLAG_GID) &&
1139	    !gid_eq(VFS_I(ip)->i_gid, icw->icw_gid))
1140		return false;
1141
1142	if ((icw->icw_flags & XFS_ICWALK_FLAG_PRID) &&
1143	    ip->i_projid != icw->icw_prid)
1144		return false;
1145
1146	return true;
1147}
1148
1149/*
1150 * A union-based inode filtering algorithm. Process the inode if any of the
1151 * criteria match. This is for global/internal scans only.
1152 */
1153STATIC bool
1154xfs_icwalk_match_id_union(
1155	struct xfs_inode	*ip,
1156	struct xfs_icwalk	*icw)
1157{
1158	if ((icw->icw_flags & XFS_ICWALK_FLAG_UID) &&
1159	    uid_eq(VFS_I(ip)->i_uid, icw->icw_uid))
1160		return true;
1161
1162	if ((icw->icw_flags & XFS_ICWALK_FLAG_GID) &&
1163	    gid_eq(VFS_I(ip)->i_gid, icw->icw_gid))
1164		return true;
1165
1166	if ((icw->icw_flags & XFS_ICWALK_FLAG_PRID) &&
1167	    ip->i_projid == icw->icw_prid)
1168		return true;
1169
1170	return false;
1171}
1172
1173/*
1174 * Is this inode @ip eligible for eof/cow block reclamation, given some
1175 * filtering parameters @icw?  The inode is eligible if @icw is null or
1176 * if the predicate functions match.
1177 */
1178static bool
1179xfs_icwalk_match(
1180	struct xfs_inode	*ip,
1181	struct xfs_icwalk	*icw)
1182{
1183	bool			match;
1184
1185	if (!icw)
1186		return true;
1187
1188	if (icw->icw_flags & XFS_ICWALK_FLAG_UNION)
1189		match = xfs_icwalk_match_id_union(ip, icw);
1190	else
1191		match = xfs_icwalk_match_id(ip, icw);
1192	if (!match)
1193		return false;
1194
1195	/* skip the inode if the file size is too small */
1196	if ((icw->icw_flags & XFS_ICWALK_FLAG_MINFILESIZE) &&
1197	    XFS_ISIZE(ip) < icw->icw_min_file_size)
1198		return false;
1199
1200	return true;
1201}
1202
1203/*
1204 * This is a fast pass over the inode cache to try to get reclaim moving on as
1205 * many inodes as possible in a short period of time. It kicks itself every few
1206 * seconds, as well as being kicked by the inode cache shrinker when memory
1207 * goes low.
1208 */
1209void
1210xfs_reclaim_worker(
1211	struct work_struct *work)
1212{
1213	struct xfs_mount *mp = container_of(to_delayed_work(work),
1214					struct xfs_mount, m_reclaim_work);
1215
1216	xfs_icwalk(mp, XFS_ICWALK_RECLAIM, NULL);
1217	xfs_reclaim_work_queue(mp);
1218}
1219
1220STATIC int
1221xfs_inode_free_eofblocks(
1222	struct xfs_inode	*ip,
1223	struct xfs_icwalk	*icw,
1224	unsigned int		*lockflags)
1225{
1226	bool			wait;
1227
1228	wait = icw && (icw->icw_flags & XFS_ICWALK_FLAG_SYNC);
1229
1230	if (!xfs_iflags_test(ip, XFS_IEOFBLOCKS))
 
 
 
1231		return 0;
 
1232
1233	/*
1234	 * If the mapping is dirty the operation can block and wait for some
1235	 * time. Unless we are waiting, skip it.
1236	 */
1237	if (!wait && mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY))
 
1238		return 0;
1239
1240	if (!xfs_icwalk_match(ip, icw))
1241		return 0;
 
 
 
 
 
 
 
 
 
 
 
1242
1243	/*
1244	 * If the caller is waiting, return -EAGAIN to keep the background
1245	 * scanner moving and revisit the inode in a subsequent pass.
1246	 */
1247	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
1248		if (wait)
1249			return -EAGAIN;
1250		return 0;
1251	}
1252	*lockflags |= XFS_IOLOCK_EXCL;
 
1253
1254	if (xfs_can_free_eofblocks(ip))
1255		return xfs_free_eofblocks(ip);
1256
1257	/* inode could be preallocated */
1258	trace_xfs_inode_free_eofblocks_invalid(ip);
1259	xfs_inode_clear_eofblocks_tag(ip);
1260	return 0;
 
 
 
 
 
 
 
 
 
 
 
1261}
1262
1263static void
1264xfs_blockgc_set_iflag(
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1265	struct xfs_inode	*ip,
1266	unsigned long		iflag)
 
1267{
1268	struct xfs_mount	*mp = ip->i_mount;
1269	struct xfs_perag	*pag;
 
 
 
 
 
 
 
1270
1271	ASSERT((iflag & ~(XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1272
1273	/*
1274	 * Don't bother locking the AG and looking up in the radix trees
1275	 * if we already know that we have the tag set.
1276	 */
1277	if (ip->i_flags & iflag)
1278		return;
1279	spin_lock(&ip->i_flags_lock);
1280	ip->i_flags |= iflag;
1281	spin_unlock(&ip->i_flags_lock);
1282
1283	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1284	spin_lock(&pag->pag_ici_lock);
1285
1286	xfs_perag_set_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
1287			XFS_ICI_BLOCKGC_TAG);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1288
1289	spin_unlock(&pag->pag_ici_lock);
1290	xfs_perag_put(pag);
1291}
1292
1293void
1294xfs_inode_set_eofblocks_tag(
1295	xfs_inode_t	*ip)
1296{
1297	trace_xfs_inode_set_eofblocks_tag(ip);
1298	return xfs_blockgc_set_iflag(ip, XFS_IEOFBLOCKS);
 
 
1299}
1300
1301static void
1302xfs_blockgc_clear_iflag(
1303	struct xfs_inode	*ip,
1304	unsigned long		iflag)
 
 
1305{
1306	struct xfs_mount	*mp = ip->i_mount;
1307	struct xfs_perag	*pag;
1308	bool			clear_tag;
1309
1310	ASSERT((iflag & ~(XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0);
1311
1312	spin_lock(&ip->i_flags_lock);
1313	ip->i_flags &= ~iflag;
1314	clear_tag = (ip->i_flags & (XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0;
1315	spin_unlock(&ip->i_flags_lock);
1316
1317	if (!clear_tag)
1318		return;
1319
1320	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1321	spin_lock(&pag->pag_ici_lock);
1322
1323	xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
1324			XFS_ICI_BLOCKGC_TAG);
 
 
 
 
 
 
 
 
 
1325
1326	spin_unlock(&pag->pag_ici_lock);
1327	xfs_perag_put(pag);
1328}
1329
1330void
1331xfs_inode_clear_eofblocks_tag(
1332	xfs_inode_t	*ip)
1333{
1334	trace_xfs_inode_clear_eofblocks_tag(ip);
1335	return xfs_blockgc_clear_iflag(ip, XFS_IEOFBLOCKS);
1336}
1337
1338/*
1339 * Prepare to free COW fork blocks from an inode.
1340 */
1341static bool
1342xfs_prep_free_cowblocks(
1343	struct xfs_inode	*ip,
1344	struct xfs_icwalk	*icw)
1345{
1346	bool			sync;
1347
1348	sync = icw && (icw->icw_flags & XFS_ICWALK_FLAG_SYNC);
1349
1350	/*
1351	 * Just clear the tag if we have an empty cow fork or none at all. It's
1352	 * possible the inode was fully unshared since it was originally tagged.
1353	 */
1354	if (!xfs_inode_has_cow_data(ip)) {
1355		trace_xfs_inode_free_cowblocks_invalid(ip);
1356		xfs_inode_clear_cowblocks_tag(ip);
1357		return false;
1358	}
1359
1360	/*
1361	 * A cowblocks trim of an inode can have a significant effect on
1362	 * fragmentation even when a reasonable COW extent size hint is set.
1363	 * Therefore, we prefer to not process cowblocks unless they are clean
1364	 * and idle. We can never process a cowblocks inode that is dirty or has
1365	 * in-flight I/O under any circumstances, because outstanding writeback
1366	 * or dio expects targeted COW fork blocks exist through write
1367	 * completion where they can be remapped into the data fork.
1368	 *
1369	 * Therefore, the heuristic used here is to never process inodes
1370	 * currently opened for write from background (i.e. non-sync) scans. For
1371	 * sync scans, use the pagecache/dio state of the inode to ensure we
1372	 * never free COW fork blocks out from under pending I/O.
1373	 */
1374	if (!sync && inode_is_open_for_write(VFS_I(ip)))
1375		return false;
1376	return xfs_can_free_cowblocks(ip);
1377}
1378
1379/*
1380 * Automatic CoW Reservation Freeing
1381 *
1382 * These functions automatically garbage collect leftover CoW reservations
1383 * that were made on behalf of a cowextsize hint when we start to run out
1384 * of quota or when the reservations sit around for too long.  If the file
1385 * has dirty pages or is undergoing writeback, its CoW reservations will
1386 * be retained.
1387 *
1388 * The actual garbage collection piggybacks off the same code that runs
1389 * the speculative EOF preallocation garbage collector.
1390 */
1391STATIC int
1392xfs_inode_free_cowblocks(
1393	struct xfs_inode	*ip,
1394	struct xfs_icwalk	*icw,
1395	unsigned int		*lockflags)
1396{
1397	bool			wait;
1398	int			ret = 0;
1399
1400	wait = icw && (icw->icw_flags & XFS_ICWALK_FLAG_SYNC);
1401
1402	if (!xfs_iflags_test(ip, XFS_ICOWBLOCKS))
1403		return 0;
1404
1405	if (!xfs_prep_free_cowblocks(ip, icw))
1406		return 0;
1407
1408	if (!xfs_icwalk_match(ip, icw))
1409		return 0;
1410
1411	/*
1412	 * If the caller is waiting, return -EAGAIN to keep the background
1413	 * scanner moving and revisit the inode in a subsequent pass.
1414	 */
1415	if (!(*lockflags & XFS_IOLOCK_EXCL) &&
1416	    !xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
1417		if (wait)
1418			return -EAGAIN;
1419		return 0;
1420	}
1421	*lockflags |= XFS_IOLOCK_EXCL;
1422
1423	if (!xfs_ilock_nowait(ip, XFS_MMAPLOCK_EXCL)) {
1424		if (wait)
1425			return -EAGAIN;
1426		return 0;
1427	}
1428	*lockflags |= XFS_MMAPLOCK_EXCL;
1429
1430	/*
1431	 * Check again, nobody else should be able to dirty blocks or change
1432	 * the reflink iflag now that we have the first two locks held.
1433	 */
1434	if (xfs_prep_free_cowblocks(ip, icw))
1435		ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false);
1436	return ret;
1437}
1438
1439void
1440xfs_inode_set_cowblocks_tag(
1441	xfs_inode_t	*ip)
1442{
1443	trace_xfs_inode_set_cowblocks_tag(ip);
1444	return xfs_blockgc_set_iflag(ip, XFS_ICOWBLOCKS);
1445}
1446
1447void
1448xfs_inode_clear_cowblocks_tag(
1449	xfs_inode_t	*ip)
1450{
1451	trace_xfs_inode_clear_cowblocks_tag(ip);
1452	return xfs_blockgc_clear_iflag(ip, XFS_ICOWBLOCKS);
1453}
1454
1455/* Disable post-EOF and CoW block auto-reclamation. */
1456void
1457xfs_blockgc_stop(
1458	struct xfs_mount	*mp)
1459{
1460	struct xfs_perag	*pag = NULL;
1461
1462	if (!xfs_clear_blockgc_enabled(mp))
1463		return;
1464
1465	while ((pag = xfs_perag_next(mp, pag)))
1466		cancel_delayed_work_sync(&pag->pag_blockgc_work);
1467	trace_xfs_blockgc_stop(mp, __return_address);
1468}
1469
1470/* Enable post-EOF and CoW block auto-reclamation. */
1471void
1472xfs_blockgc_start(
1473	struct xfs_mount	*mp)
1474{
1475	struct xfs_perag	*pag = NULL;
1476
1477	if (xfs_set_blockgc_enabled(mp))
1478		return;
1479
1480	trace_xfs_blockgc_start(mp, __return_address);
1481	while ((pag = xfs_perag_grab_next_tag(mp, pag, XFS_ICI_BLOCKGC_TAG)))
1482		xfs_blockgc_queue(pag);
1483}
1484
1485/* Don't try to run block gc on an inode that's in any of these states. */
1486#define XFS_BLOCKGC_NOGRAB_IFLAGS	(XFS_INEW | \
1487					 XFS_NEED_INACTIVE | \
1488					 XFS_INACTIVATING | \
1489					 XFS_IRECLAIMABLE | \
1490					 XFS_IRECLAIM)
1491/*
1492 * Decide if the given @ip is eligible for garbage collection of speculative
1493 * preallocations, and grab it if so.  Returns true if it's ready to go or
1494 * false if we should just ignore it.
1495 */
1496static bool
1497xfs_blockgc_igrab(
1498	struct xfs_inode	*ip)
1499{
1500	struct inode		*inode = VFS_I(ip);
1501
1502	ASSERT(rcu_read_lock_held());
1503
1504	/* Check for stale RCU freed inode */
1505	spin_lock(&ip->i_flags_lock);
1506	if (!ip->i_ino)
1507		goto out_unlock_noent;
1508
1509	if (ip->i_flags & XFS_BLOCKGC_NOGRAB_IFLAGS)
1510		goto out_unlock_noent;
1511	spin_unlock(&ip->i_flags_lock);
1512
1513	/* nothing to sync during shutdown */
1514	if (xfs_is_shutdown(ip->i_mount))
1515		return false;
1516
1517	/* If we can't grab the inode, it must on it's way to reclaim. */
1518	if (!igrab(inode))
1519		return false;
1520
1521	/* inode is valid */
1522	return true;
1523
1524out_unlock_noent:
1525	spin_unlock(&ip->i_flags_lock);
1526	return false;
1527}
1528
1529/* Scan one incore inode for block preallocations that we can remove. */
1530static int
1531xfs_blockgc_scan_inode(
1532	struct xfs_inode	*ip,
1533	struct xfs_icwalk	*icw)
1534{
1535	unsigned int		lockflags = 0;
1536	int			error;
1537
1538	error = xfs_inode_free_eofblocks(ip, icw, &lockflags);
1539	if (error)
1540		goto unlock;
1541
1542	error = xfs_inode_free_cowblocks(ip, icw, &lockflags);
1543unlock:
1544	if (lockflags)
1545		xfs_iunlock(ip, lockflags);
1546	xfs_irele(ip);
1547	return error;
1548}
1549
1550/* Background worker that trims preallocated space. */
1551void
1552xfs_blockgc_worker(
1553	struct work_struct	*work)
1554{
1555	struct xfs_perag	*pag = container_of(to_delayed_work(work),
1556					struct xfs_perag, pag_blockgc_work);
1557	struct xfs_mount	*mp = pag_mount(pag);
1558	int			error;
1559
1560	trace_xfs_blockgc_worker(mp, __return_address);
1561
1562	error = xfs_icwalk_ag(pag, XFS_ICWALK_BLOCKGC, NULL);
1563	if (error)
1564		xfs_info(mp, "AG %u preallocation gc worker failed, err=%d",
1565				pag_agno(pag), error);
1566	xfs_blockgc_queue(pag);
1567}
1568
1569/*
1570 * Try to free space in the filesystem by purging inactive inodes, eofblocks
1571 * and cowblocks.
1572 */
1573int
1574xfs_blockgc_free_space(
1575	struct xfs_mount	*mp,
1576	struct xfs_icwalk	*icw)
1577{
1578	int			error;
1579
1580	trace_xfs_blockgc_free_space(mp, icw, _RET_IP_);
1581
1582	error = xfs_icwalk(mp, XFS_ICWALK_BLOCKGC, icw);
1583	if (error)
1584		return error;
1585
1586	return xfs_inodegc_flush(mp);
1587}
1588
1589/*
1590 * Reclaim all the free space that we can by scheduling the background blockgc
1591 * and inodegc workers immediately and waiting for them all to clear.
1592 */
1593int
1594xfs_blockgc_flush_all(
1595	struct xfs_mount	*mp)
1596{
1597	struct xfs_perag	*pag = NULL;
1598
1599	trace_xfs_blockgc_flush_all(mp, __return_address);
1600
1601	/*
1602	 * For each blockgc worker, move its queue time up to now.  If it wasn't
1603	 * queued, it will not be requeued.  Then flush whatever is left.
1604	 */
1605	while ((pag = xfs_perag_grab_next_tag(mp, pag, XFS_ICI_BLOCKGC_TAG)))
1606		mod_delayed_work(mp->m_blockgc_wq, &pag->pag_blockgc_work, 0);
1607
1608	while ((pag = xfs_perag_grab_next_tag(mp, pag, XFS_ICI_BLOCKGC_TAG)))
1609		flush_delayed_work(&pag->pag_blockgc_work);
1610
1611	return xfs_inodegc_flush(mp);
1612}
1613
1614/*
1615 * Run cow/eofblocks scans on the supplied dquots.  We don't know exactly which
1616 * quota caused an allocation failure, so we make a best effort by including
1617 * each quota under low free space conditions (less than 1% free space) in the
1618 * scan.
1619 *
1620 * Callers must not hold any inode's ILOCK.  If requesting a synchronous scan
1621 * (XFS_ICWALK_FLAG_SYNC), the caller also must not hold any inode's IOLOCK or
1622 * MMAPLOCK.
1623 */
1624int
1625xfs_blockgc_free_dquots(
1626	struct xfs_mount	*mp,
1627	struct xfs_dquot	*udqp,
1628	struct xfs_dquot	*gdqp,
1629	struct xfs_dquot	*pdqp,
1630	unsigned int		iwalk_flags)
1631{
1632	struct xfs_icwalk	icw = {0};
1633	bool			do_work = false;
1634
1635	if (!udqp && !gdqp && !pdqp)
1636		return 0;
1637
1638	/*
1639	 * Run a scan to free blocks using the union filter to cover all
1640	 * applicable quotas in a single scan.
1641	 */
1642	icw.icw_flags = XFS_ICWALK_FLAG_UNION | iwalk_flags;
 
 
1643
1644	if (XFS_IS_UQUOTA_ENFORCED(mp) && udqp && xfs_dquot_lowsp(udqp)) {
1645		icw.icw_uid = make_kuid(mp->m_super->s_user_ns, udqp->q_id);
1646		icw.icw_flags |= XFS_ICWALK_FLAG_UID;
1647		do_work = true;
1648	}
1649
1650	if (XFS_IS_UQUOTA_ENFORCED(mp) && gdqp && xfs_dquot_lowsp(gdqp)) {
1651		icw.icw_gid = make_kgid(mp->m_super->s_user_ns, gdqp->q_id);
1652		icw.icw_flags |= XFS_ICWALK_FLAG_GID;
1653		do_work = true;
1654	}
1655
1656	if (XFS_IS_PQUOTA_ENFORCED(mp) && pdqp && xfs_dquot_lowsp(pdqp)) {
1657		icw.icw_prid = pdqp->q_id;
1658		icw.icw_flags |= XFS_ICWALK_FLAG_PRID;
1659		do_work = true;
1660	}
1661
1662	if (!do_work)
1663		return 0;
1664
1665	return xfs_blockgc_free_space(mp, &icw);
1666}
1667
1668/* Run cow/eofblocks scans on the quotas attached to the inode. */
1669int
1670xfs_blockgc_free_quota(
1671	struct xfs_inode	*ip,
1672	unsigned int		iwalk_flags)
1673{
1674	return xfs_blockgc_free_dquots(ip->i_mount,
1675			xfs_inode_dquot(ip, XFS_DQTYPE_USER),
1676			xfs_inode_dquot(ip, XFS_DQTYPE_GROUP),
1677			xfs_inode_dquot(ip, XFS_DQTYPE_PROJ), iwalk_flags);
1678}
1679
1680/* XFS Inode Cache Walking Code */
1681
1682/*
1683 * The inode lookup is done in batches to keep the amount of lock traffic and
1684 * radix tree lookups to a minimum. The batch size is a trade off between
1685 * lookup reduction and stack usage. This is in the reclaim path, so we can't
1686 * be too greedy.
1687 */
1688#define XFS_LOOKUP_BATCH	32
1689
1690
1691/*
1692 * Decide if we want to grab this inode in anticipation of doing work towards
1693 * the goal.
1694 */
1695static inline bool
1696xfs_icwalk_igrab(
1697	enum xfs_icwalk_goal	goal,
1698	struct xfs_inode	*ip,
1699	struct xfs_icwalk	*icw)
1700{
1701	switch (goal) {
1702	case XFS_ICWALK_BLOCKGC:
1703		return xfs_blockgc_igrab(ip);
1704	case XFS_ICWALK_RECLAIM:
1705		return xfs_reclaim_igrab(ip, icw);
1706	default:
1707		return false;
1708	}
1709}
1710
1711/*
1712 * Process an inode.  Each processing function must handle any state changes
1713 * made by the icwalk igrab function.  Return -EAGAIN to skip an inode.
1714 */
1715static inline int
1716xfs_icwalk_process_inode(
1717	enum xfs_icwalk_goal	goal,
1718	struct xfs_inode	*ip,
1719	struct xfs_perag	*pag,
1720	struct xfs_icwalk	*icw)
1721{
1722	int			error = 0;
1723
1724	switch (goal) {
1725	case XFS_ICWALK_BLOCKGC:
1726		error = xfs_blockgc_scan_inode(ip, icw);
1727		break;
1728	case XFS_ICWALK_RECLAIM:
1729		xfs_reclaim_inode(ip, pag);
1730		break;
1731	}
1732	return error;
1733}
1734
1735/*
1736 * For a given per-AG structure @pag and a goal, grab qualifying inodes and
1737 * process them in some manner.
1738 */
1739static int
1740xfs_icwalk_ag(
1741	struct xfs_perag	*pag,
1742	enum xfs_icwalk_goal	goal,
1743	struct xfs_icwalk	*icw)
1744{
1745	struct xfs_mount	*mp = pag_mount(pag);
1746	uint32_t		first_index;
1747	int			last_error = 0;
1748	int			skipped;
1749	bool			done;
1750	int			nr_found;
1751
1752restart:
1753	done = false;
1754	skipped = 0;
1755	if (goal == XFS_ICWALK_RECLAIM)
1756		first_index = READ_ONCE(pag->pag_ici_reclaim_cursor);
1757	else
1758		first_index = 0;
1759	nr_found = 0;
1760	do {
1761		struct xfs_inode *batch[XFS_LOOKUP_BATCH];
1762		int		error = 0;
1763		int		i;
1764
1765		rcu_read_lock();
1766
1767		nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
1768				(void **) batch, first_index,
1769				XFS_LOOKUP_BATCH, goal);
1770		if (!nr_found) {
1771			done = true;
1772			rcu_read_unlock();
1773			break;
1774		}
1775
1776		/*
1777		 * Grab the inodes before we drop the lock. if we found
1778		 * nothing, nr == 0 and the loop will be skipped.
1779		 */
1780		for (i = 0; i < nr_found; i++) {
1781			struct xfs_inode *ip = batch[i];
1782
1783			if (done || !xfs_icwalk_igrab(goal, ip, icw))
1784				batch[i] = NULL;
1785
1786			/*
1787			 * Update the index for the next lookup. Catch
1788			 * overflows into the next AG range which can occur if
1789			 * we have inodes in the last block of the AG and we
1790			 * are currently pointing to the last inode.
1791			 *
1792			 * Because we may see inodes that are from the wrong AG
1793			 * due to RCU freeing and reallocation, only update the
1794			 * index if it lies in this AG. It was a race that lead
1795			 * us to see this inode, so another lookup from the
1796			 * same index will not find it again.
1797			 */
1798			if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag_agno(pag))
1799				continue;
1800			first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
1801			if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
1802				done = true;
1803		}
1804
1805		/* unlock now we've grabbed the inodes. */
1806		rcu_read_unlock();
1807
1808		for (i = 0; i < nr_found; i++) {
1809			if (!batch[i])
1810				continue;
1811			error = xfs_icwalk_process_inode(goal, batch[i], pag,
1812					icw);
1813			if (error == -EAGAIN) {
1814				skipped++;
1815				continue;
1816			}
1817			if (error && last_error != -EFSCORRUPTED)
1818				last_error = error;
1819		}
1820
1821		/* bail out if the filesystem is corrupted.  */
1822		if (error == -EFSCORRUPTED)
1823			break;
1824
1825		cond_resched();
1826
1827		if (icw && (icw->icw_flags & XFS_ICWALK_FLAG_SCAN_LIMIT)) {
1828			icw->icw_scan_limit -= XFS_LOOKUP_BATCH;
1829			if (icw->icw_scan_limit <= 0)
1830				break;
1831		}
1832	} while (nr_found && !done);
1833
1834	if (goal == XFS_ICWALK_RECLAIM) {
1835		if (done)
1836			first_index = 0;
1837		WRITE_ONCE(pag->pag_ici_reclaim_cursor, first_index);
1838	}
1839
1840	if (skipped) {
1841		delay(1);
1842		goto restart;
1843	}
1844	return last_error;
1845}
1846
1847/* Walk all incore inodes to achieve a given goal. */
1848static int
1849xfs_icwalk(
1850	struct xfs_mount	*mp,
1851	enum xfs_icwalk_goal	goal,
1852	struct xfs_icwalk	*icw)
1853{
1854	struct xfs_perag	*pag = NULL;
1855	int			error = 0;
1856	int			last_error = 0;
1857
1858	while ((pag = xfs_perag_grab_next_tag(mp, pag, goal))) {
1859		error = xfs_icwalk_ag(pag, goal, icw);
1860		if (error) {
1861			last_error = error;
1862			if (error == -EFSCORRUPTED) {
1863				xfs_perag_rele(pag);
1864				break;
1865			}
1866		}
1867	}
1868	return last_error;
1869	BUILD_BUG_ON(XFS_ICWALK_PRIVATE_FLAGS & XFS_ICWALK_FLAGS_VALID);
1870}
1871
1872#ifdef DEBUG
1873static void
1874xfs_check_delalloc(
1875	struct xfs_inode	*ip,
1876	int			whichfork)
1877{
1878	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
1879	struct xfs_bmbt_irec	got;
1880	struct xfs_iext_cursor	icur;
1881
1882	if (!ifp || !xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got))
1883		return;
1884	do {
1885		if (isnullstartblock(got.br_startblock)) {
1886			xfs_warn(ip->i_mount,
1887	"ino %llx %s fork has delalloc extent at [0x%llx:0x%llx]",
1888				ip->i_ino,
1889				whichfork == XFS_DATA_FORK ? "data" : "cow",
1890				got.br_startoff, got.br_blockcount);
1891		}
1892	} while (xfs_iext_next_extent(ifp, &icur, &got));
1893}
1894#else
1895#define xfs_check_delalloc(ip, whichfork)	do { } while (0)
1896#endif
1897
1898/* Schedule the inode for reclaim. */
1899static void
1900xfs_inodegc_set_reclaimable(
1901	struct xfs_inode	*ip)
1902{
1903	struct xfs_mount	*mp = ip->i_mount;
1904	struct xfs_perag	*pag;
1905
1906	if (!xfs_is_shutdown(mp) && ip->i_delayed_blks) {
1907		xfs_check_delalloc(ip, XFS_DATA_FORK);
1908		xfs_check_delalloc(ip, XFS_COW_FORK);
1909		ASSERT(0);
1910	}
1911
1912	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1913	spin_lock(&pag->pag_ici_lock);
1914	spin_lock(&ip->i_flags_lock);
1915
1916	trace_xfs_inode_set_reclaimable(ip);
1917	ip->i_flags &= ~(XFS_NEED_INACTIVE | XFS_INACTIVATING);
1918	ip->i_flags |= XFS_IRECLAIMABLE;
1919	xfs_perag_set_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
1920			XFS_ICI_RECLAIM_TAG);
1921
1922	spin_unlock(&ip->i_flags_lock);
1923	spin_unlock(&pag->pag_ici_lock);
1924	xfs_perag_put(pag);
1925}
1926
1927/*
1928 * Free all speculative preallocations and possibly even the inode itself.
1929 * This is the last chance to make changes to an otherwise unreferenced file
1930 * before incore reclamation happens.
1931 */
1932static int
1933xfs_inodegc_inactivate(
1934	struct xfs_inode	*ip)
1935{
1936	int			error;
1937
1938	trace_xfs_inode_inactivating(ip);
1939	error = xfs_inactive(ip);
1940	xfs_inodegc_set_reclaimable(ip);
1941	return error;
1942
1943}
1944
1945void
1946xfs_inodegc_worker(
1947	struct work_struct	*work)
1948{
1949	struct xfs_inodegc	*gc = container_of(to_delayed_work(work),
1950						struct xfs_inodegc, work);
1951	struct llist_node	*node = llist_del_all(&gc->list);
1952	struct xfs_inode	*ip, *n;
1953	struct xfs_mount	*mp = gc->mp;
1954	unsigned int		nofs_flag;
1955
1956	/*
1957	 * Clear the cpu mask bit and ensure that we have seen the latest
1958	 * update of the gc structure associated with this CPU. This matches
1959	 * with the release semantics used when setting the cpumask bit in
1960	 * xfs_inodegc_queue.
1961	 */
1962	cpumask_clear_cpu(gc->cpu, &mp->m_inodegc_cpumask);
1963	smp_mb__after_atomic();
1964
1965	WRITE_ONCE(gc->items, 0);
1966
1967	if (!node)
1968		return;
1969
1970	/*
1971	 * We can allocate memory here while doing writeback on behalf of
1972	 * memory reclaim.  To avoid memory allocation deadlocks set the
1973	 * task-wide nofs context for the following operations.
1974	 */
1975	nofs_flag = memalloc_nofs_save();
1976
1977	ip = llist_entry(node, struct xfs_inode, i_gclist);
1978	trace_xfs_inodegc_worker(mp, READ_ONCE(gc->shrinker_hits));
1979
1980	WRITE_ONCE(gc->shrinker_hits, 0);
1981	llist_for_each_entry_safe(ip, n, node, i_gclist) {
1982		int	error;
1983
1984		xfs_iflags_set(ip, XFS_INACTIVATING);
1985		error = xfs_inodegc_inactivate(ip);
1986		if (error && !gc->error)
1987			gc->error = error;
1988	}
1989
1990	memalloc_nofs_restore(nofs_flag);
1991}
1992
1993/*
1994 * Expedite all pending inodegc work to run immediately. This does not wait for
1995 * completion of the work.
1996 */
1997void
1998xfs_inodegc_push(
1999	struct xfs_mount	*mp)
2000{
2001	if (!xfs_is_inodegc_enabled(mp))
2002		return;
2003	trace_xfs_inodegc_push(mp, __return_address);
2004	xfs_inodegc_queue_all(mp);
2005}
2006
2007/*
2008 * Force all currently queued inode inactivation work to run immediately and
2009 * wait for the work to finish.
2010 */
2011int
2012xfs_inodegc_flush(
2013	struct xfs_mount	*mp)
2014{
2015	xfs_inodegc_push(mp);
2016	trace_xfs_inodegc_flush(mp, __return_address);
2017	return xfs_inodegc_wait_all(mp);
2018}
2019
2020/*
2021 * Flush all the pending work and then disable the inode inactivation background
2022 * workers and wait for them to stop.  Caller must hold sb->s_umount to
2023 * coordinate changes in the inodegc_enabled state.
2024 */
2025void
2026xfs_inodegc_stop(
2027	struct xfs_mount	*mp)
2028{
2029	bool			rerun;
2030
2031	if (!xfs_clear_inodegc_enabled(mp))
2032		return;
2033
2034	/*
2035	 * Drain all pending inodegc work, including inodes that could be
2036	 * queued by racing xfs_inodegc_queue or xfs_inodegc_shrinker_scan
2037	 * threads that sample the inodegc state just prior to us clearing it.
2038	 * The inodegc flag state prevents new threads from queuing more
2039	 * inodes, so we queue pending work items and flush the workqueue until
2040	 * all inodegc lists are empty.  IOWs, we cannot use drain_workqueue
2041	 * here because it does not allow other unserialized mechanisms to
2042	 * reschedule inodegc work while this draining is in progress.
2043	 */
2044	xfs_inodegc_queue_all(mp);
2045	do {
2046		flush_workqueue(mp->m_inodegc_wq);
2047		rerun = xfs_inodegc_queue_all(mp);
2048	} while (rerun);
2049
2050	trace_xfs_inodegc_stop(mp, __return_address);
2051}
2052
2053/*
2054 * Enable the inode inactivation background workers and schedule deferred inode
2055 * inactivation work if there is any.  Caller must hold sb->s_umount to
2056 * coordinate changes in the inodegc_enabled state.
2057 */
2058void
2059xfs_inodegc_start(
2060	struct xfs_mount	*mp)
2061{
2062	if (xfs_set_inodegc_enabled(mp))
2063		return;
2064
2065	trace_xfs_inodegc_start(mp, __return_address);
2066	xfs_inodegc_queue_all(mp);
2067}
2068
2069#ifdef CONFIG_XFS_RT
2070static inline bool
2071xfs_inodegc_want_queue_rt_file(
2072	struct xfs_inode	*ip)
2073{
2074	struct xfs_mount	*mp = ip->i_mount;
2075
2076	if (!XFS_IS_REALTIME_INODE(ip))
2077		return false;
2078
2079	if (__percpu_counter_compare(&mp->m_frextents,
2080				mp->m_low_rtexts[XFS_LOWSP_5_PCNT],
2081				XFS_FDBLOCKS_BATCH) < 0)
2082		return true;
2083
2084	return false;
2085}
2086#else
2087# define xfs_inodegc_want_queue_rt_file(ip)	(false)
2088#endif /* CONFIG_XFS_RT */
2089
2090/*
2091 * Schedule the inactivation worker when:
2092 *
2093 *  - We've accumulated more than one inode cluster buffer's worth of inodes.
2094 *  - There is less than 5% free space left.
2095 *  - Any of the quotas for this inode are near an enforcement limit.
2096 */
2097static inline bool
2098xfs_inodegc_want_queue_work(
2099	struct xfs_inode	*ip,
2100	unsigned int		items)
2101{
2102	struct xfs_mount	*mp = ip->i_mount;
2103
2104	if (items > mp->m_ino_geo.inodes_per_cluster)
2105		return true;
2106
2107	if (__percpu_counter_compare(&mp->m_fdblocks,
2108				mp->m_low_space[XFS_LOWSP_5_PCNT],
2109				XFS_FDBLOCKS_BATCH) < 0)
2110		return true;
2111
2112	if (xfs_inodegc_want_queue_rt_file(ip))
2113		return true;
2114
2115	if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_USER))
2116		return true;
2117
2118	if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_GROUP))
2119		return true;
2120
2121	if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_PROJ))
2122		return true;
2123
2124	return false;
2125}
2126
2127/*
2128 * Upper bound on the number of inodes in each AG that can be queued for
2129 * inactivation at any given time, to avoid monopolizing the workqueue.
2130 */
2131#define XFS_INODEGC_MAX_BACKLOG		(4 * XFS_INODES_PER_CHUNK)
2132
2133/*
2134 * Make the frontend wait for inactivations when:
2135 *
2136 *  - Memory shrinkers queued the inactivation worker and it hasn't finished.
2137 *  - The queue depth exceeds the maximum allowable percpu backlog.
2138 *
2139 * Note: If we are in a NOFS context here (e.g. current thread is running a
2140 * transaction) the we don't want to block here as inodegc progress may require
2141 * filesystem resources we hold to make progress and that could result in a
2142 * deadlock. Hence we skip out of here if we are in a scoped NOFS context.
2143 */
2144static inline bool
2145xfs_inodegc_want_flush_work(
2146	struct xfs_inode	*ip,
2147	unsigned int		items,
2148	unsigned int		shrinker_hits)
2149{
2150	if (current->flags & PF_MEMALLOC_NOFS)
2151		return false;
2152
2153	if (shrinker_hits > 0)
2154		return true;
2155
2156	if (items > XFS_INODEGC_MAX_BACKLOG)
2157		return true;
2158
2159	return false;
2160}
2161
2162/*
2163 * Queue a background inactivation worker if there are inodes that need to be
2164 * inactivated and higher level xfs code hasn't disabled the background
2165 * workers.
2166 */
2167static void
2168xfs_inodegc_queue(
2169	struct xfs_inode	*ip)
2170{
2171	struct xfs_mount	*mp = ip->i_mount;
2172	struct xfs_inodegc	*gc;
2173	int			items;
2174	unsigned int		shrinker_hits;
2175	unsigned int		cpu_nr;
2176	unsigned long		queue_delay = 1;
2177
2178	trace_xfs_inode_set_need_inactive(ip);
2179	spin_lock(&ip->i_flags_lock);
2180	ip->i_flags |= XFS_NEED_INACTIVE;
2181	spin_unlock(&ip->i_flags_lock);
2182
2183	cpu_nr = get_cpu();
2184	gc = this_cpu_ptr(mp->m_inodegc);
2185	llist_add(&ip->i_gclist, &gc->list);
2186	items = READ_ONCE(gc->items);
2187	WRITE_ONCE(gc->items, items + 1);
2188	shrinker_hits = READ_ONCE(gc->shrinker_hits);
2189
2190	/*
2191	 * Ensure the list add is always seen by anyone who finds the cpumask
2192	 * bit set. This effectively gives the cpumask bit set operation
2193	 * release ordering semantics.
2194	 */
2195	smp_mb__before_atomic();
2196	if (!cpumask_test_cpu(cpu_nr, &mp->m_inodegc_cpumask))
2197		cpumask_test_and_set_cpu(cpu_nr, &mp->m_inodegc_cpumask);
2198
2199	/*
2200	 * We queue the work while holding the current CPU so that the work
2201	 * is scheduled to run on this CPU.
2202	 */
2203	if (!xfs_is_inodegc_enabled(mp)) {
2204		put_cpu();
2205		return;
2206	}
2207
2208	if (xfs_inodegc_want_queue_work(ip, items))
2209		queue_delay = 0;
2210
2211	trace_xfs_inodegc_queue(mp, __return_address);
2212	mod_delayed_work_on(current_cpu(), mp->m_inodegc_wq, &gc->work,
2213			queue_delay);
2214	put_cpu();
2215
2216	if (xfs_inodegc_want_flush_work(ip, items, shrinker_hits)) {
2217		trace_xfs_inodegc_throttle(mp, __return_address);
2218		flush_delayed_work(&gc->work);
2219	}
2220}
2221
2222/*
2223 * We set the inode flag atomically with the radix tree tag.  Once we get tag
2224 * lookups on the radix tree, this inode flag can go away.
2225 *
2226 * We always use background reclaim here because even if the inode is clean, it
2227 * still may be under IO and hence we have wait for IO completion to occur
2228 * before we can reclaim the inode. The background reclaim path handles this
2229 * more efficiently than we can here, so simply let background reclaim tear down
2230 * all inodes.
2231 */
2232void
2233xfs_inode_mark_reclaimable(
2234	struct xfs_inode	*ip)
2235{
2236	struct xfs_mount	*mp = ip->i_mount;
2237	bool			need_inactive;
2238
2239	XFS_STATS_INC(mp, vn_reclaim);
2240
2241	/*
2242	 * We should never get here with any of the reclaim flags already set.
2243	 */
2244	ASSERT_ALWAYS(!xfs_iflags_test(ip, XFS_ALL_IRECLAIM_FLAGS));
2245
2246	need_inactive = xfs_inode_needs_inactive(ip);
2247	if (need_inactive) {
2248		xfs_inodegc_queue(ip);
2249		return;
2250	}
2251
2252	/* Going straight to reclaim, so drop the dquots. */
2253	xfs_qm_dqdetach(ip);
2254	xfs_inodegc_set_reclaimable(ip);
2255}
2256
2257/*
2258 * Register a phony shrinker so that we can run background inodegc sooner when
2259 * there's memory pressure.  Inactivation does not itself free any memory but
2260 * it does make inodes reclaimable, which eventually frees memory.
2261 *
2262 * The count function, seek value, and batch value are crafted to trigger the
2263 * scan function during the second round of scanning.  Hopefully this means
2264 * that we reclaimed enough memory that initiating metadata transactions won't
2265 * make things worse.
2266 */
2267#define XFS_INODEGC_SHRINKER_COUNT	(1UL << DEF_PRIORITY)
2268#define XFS_INODEGC_SHRINKER_BATCH	((XFS_INODEGC_SHRINKER_COUNT / 2) + 1)
2269
2270static unsigned long
2271xfs_inodegc_shrinker_count(
2272	struct shrinker		*shrink,
2273	struct shrink_control	*sc)
2274{
2275	struct xfs_mount	*mp = shrink->private_data;
2276	struct xfs_inodegc	*gc;
2277	int			cpu;
2278
2279	if (!xfs_is_inodegc_enabled(mp))
2280		return 0;
2281
2282	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
2283		gc = per_cpu_ptr(mp->m_inodegc, cpu);
2284		if (!llist_empty(&gc->list))
2285			return XFS_INODEGC_SHRINKER_COUNT;
2286	}
2287
2288	return 0;
2289}
2290
2291static unsigned long
2292xfs_inodegc_shrinker_scan(
2293	struct shrinker		*shrink,
2294	struct shrink_control	*sc)
2295{
2296	struct xfs_mount	*mp = shrink->private_data;
2297	struct xfs_inodegc	*gc;
2298	int			cpu;
2299	bool			no_items = true;
2300
2301	if (!xfs_is_inodegc_enabled(mp))
2302		return SHRINK_STOP;
2303
2304	trace_xfs_inodegc_shrinker_scan(mp, sc, __return_address);
2305
2306	for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
2307		gc = per_cpu_ptr(mp->m_inodegc, cpu);
2308		if (!llist_empty(&gc->list)) {
2309			unsigned int	h = READ_ONCE(gc->shrinker_hits);
2310
2311			WRITE_ONCE(gc->shrinker_hits, h + 1);
2312			mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
2313			no_items = false;
2314		}
2315	}
2316
2317	/*
2318	 * If there are no inodes to inactivate, we don't want the shrinker
2319	 * to think there's deferred work to call us back about.
2320	 */
2321	if (no_items)
2322		return LONG_MAX;
2323
2324	return SHRINK_STOP;
2325}
2326
2327/* Register a shrinker so we can accelerate inodegc and throttle queuing. */
2328int
2329xfs_inodegc_register_shrinker(
2330	struct xfs_mount	*mp)
2331{
2332	mp->m_inodegc_shrinker = shrinker_alloc(SHRINKER_NONSLAB,
2333						"xfs-inodegc:%s",
2334						mp->m_super->s_id);
2335	if (!mp->m_inodegc_shrinker)
2336		return -ENOMEM;
2337
2338	mp->m_inodegc_shrinker->count_objects = xfs_inodegc_shrinker_count;
2339	mp->m_inodegc_shrinker->scan_objects = xfs_inodegc_shrinker_scan;
2340	mp->m_inodegc_shrinker->seeks = 0;
2341	mp->m_inodegc_shrinker->batch = XFS_INODEGC_SHRINKER_BATCH;
2342	mp->m_inodegc_shrinker->private_data = mp;
2343
2344	shrinker_register(mp->m_inodegc_shrinker);
2345
2346	return 0;
2347}