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// SPDX-License-Identifier: GPL-2.0-only/* * (C) 1997 Linus Torvalds * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation) */#include <linux/export.h>#include <linux/fs.h>#include <linux/filelock.h>#include <linux/mm.h>#include <linux/backing-dev.h>#include <linux/hash.h>#include <linux/swap.h>#include <linux/security.h>#include <linux/cdev.h>#include <linux/memblock.h>#include <linux/fsnotify.h>#include <linux/fsverity.h>#include <linux/mount.h>#include <linux/posix_acl.h>#include <linux/ratelimit.h>#include <linux/list_lru.h>#include <linux/iversion.h>#include <linux/rw_hint.h>#include <linux/seq_file.h>#include <linux/debugfs.h>#include <trace/events/writeback.h>#define CREATE_TRACE_POINTS#include <trace/events/timestamp.h> #include "internal.h" /* * Inode locking rules: * * inode->i_lock protects: *   inode->i_state, inode->i_hash, __iget(), inode->i_io_list * Inode LRU list locks protect: *   inode->i_sb->s_inode_lru, inode->i_lru * inode->i_sb->s_inode_list_lock protects: *   inode->i_sb->s_inodes, inode->i_sb_list * bdi->wb.list_lock protects: *   bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list * inode_hash_lock protects: *   inode_hashtable, inode->i_hash * * Lock ordering: * * inode->i_sb->s_inode_list_lock *   inode->i_lock *     Inode LRU list locks * * bdi->wb.list_lock *   inode->i_lock * * inode_hash_lock *   inode->i_lock */ static unsigned int i_hash_mask __ro_after_init;static unsigned int i_hash_shift __ro_after_init;static struct hlist_head *inode_hashtable __ro_after_init;static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); /* * Empty aops. Can be used for the cases where the user does not * define any of the address_space operations. */const struct address_space_operations empty_aops = {};EXPORT_SYMBOL(empty_aops); static DEFINE_PER_CPU(unsigned long, nr_inodes);static DEFINE_PER_CPU(unsigned long, nr_unused); static struct kmem_cache *inode_cachep __ro_after_init; static long get_nr_inodes(void){	int i;	long sum = 0;	for_each_possible_cpu(i)		sum += per_cpu(nr_inodes, i);	return sum < 0 ? 0 : sum;} static inline long get_nr_inodes_unused(void){	int i;	long sum = 0;	for_each_possible_cpu(i)		sum += per_cpu(nr_unused, i);	return sum < 0 ? 0 : sum;} long get_nr_dirty_inodes(void){	/* not actually dirty inodes, but a wild approximation */	long nr_dirty = get_nr_inodes() - get_nr_inodes_unused();	return nr_dirty > 0 ? nr_dirty : 0;} #ifdef CONFIG_DEBUG_FSstatic DEFINE_PER_CPU(long, mg_ctime_updates);static DEFINE_PER_CPU(long, mg_fine_stamps);static DEFINE_PER_CPU(long, mg_ctime_swaps); static unsigned long get_mg_ctime_updates(void){	unsigned long sum = 0;	int i; 	for_each_possible_cpu(i)		sum += data_race(per_cpu(mg_ctime_updates, i));	return sum;} static unsigned long get_mg_fine_stamps(void){	unsigned long sum = 0;	int i; 	for_each_possible_cpu(i)		sum += data_race(per_cpu(mg_fine_stamps, i));	return sum;} static unsigned long get_mg_ctime_swaps(void){	unsigned long sum = 0;	int i; 	for_each_possible_cpu(i)		sum += data_race(per_cpu(mg_ctime_swaps, i));	return sum;} #define mgtime_counter_inc(__var)	this_cpu_inc(__var) static int mgts_show(struct seq_file *s, void *p){	unsigned long ctime_updates = get_mg_ctime_updates();	unsigned long ctime_swaps = get_mg_ctime_swaps();	unsigned long fine_stamps = get_mg_fine_stamps();	unsigned long floor_swaps = timekeeping_get_mg_floor_swaps(); 	seq_printf(s, "%lu %lu %lu %lu\n",		   ctime_updates, ctime_swaps, fine_stamps, floor_swaps);	return 0;} DEFINE_SHOW_ATTRIBUTE(mgts); static int __init mg_debugfs_init(void){	debugfs_create_file("multigrain_timestamps", S_IFREG | S_IRUGO, NULL, NULL, &mgts_fops);	return 0;}late_initcall(mg_debugfs_init); #else /* ! CONFIG_DEBUG_FS */ #define mgtime_counter_inc(__var)	do { } while (0) #endif /* CONFIG_DEBUG_FS */ /* * Handle nr_inode sysctl */#ifdef CONFIG_SYSCTL/* * Statistics gathering.. */static struct inodes_stat_t inodes_stat; static int proc_nr_inodes(const struct ctl_table *table, int write, void *buffer,			  size_t *lenp, loff_t *ppos){	inodes_stat.nr_inodes = get_nr_inodes();	inodes_stat.nr_unused = get_nr_inodes_unused();	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);} static const struct ctl_table inodes_sysctls[] = {	{		.procname	= "inode-nr",		.data		= &inodes_stat,		.maxlen		= 2*sizeof(long),		.mode		= 0444,		.proc_handler	= proc_nr_inodes,	},	{		.procname	= "inode-state",		.data		= &inodes_stat,		.maxlen		= 7*sizeof(long),		.mode		= 0444,		.proc_handler	= proc_nr_inodes,	},}; static int __init init_fs_inode_sysctls(void){	register_sysctl_init("fs", inodes_sysctls);	return 0;}early_initcall(init_fs_inode_sysctls);#endif static int no_open(struct inode *inode, struct file *file){	return -ENXIO;} /** * inode_init_always_gfp - perform inode structure initialisation * @sb: superblock inode belongs to * @inode: inode to initialise * @gfp: allocation flags * * These are initializations that need to be done on every inode * allocation as the fields are not initialised by slab allocation. * If there are additional allocations required @gfp is used. */int inode_init_always_gfp(struct super_block *sb, struct inode *inode, gfp_t gfp){	static const struct inode_operations empty_iops;	static const struct file_operations no_open_fops = {.open = no_open};	struct address_space *const mapping = &inode->i_data; 	inode->i_sb = sb;	inode->i_blkbits = sb->s_blocksize_bits;	inode->i_flags = 0;	inode_state_assign_raw(inode, 0);	atomic64_set(&inode->i_sequence, 0);	atomic_set(&inode->i_count, 1);	inode->i_op = &empty_iops;	inode->i_fop = &no_open_fops;	inode->i_ino = 0;	inode->__i_nlink = 1;	inode->i_opflags = 0;	if (sb->s_xattr)		inode->i_opflags |= IOP_XATTR;	if (sb->s_type->fs_flags & FS_MGTIME)		inode->i_opflags |= IOP_MGTIME;	i_uid_write(inode, 0);	i_gid_write(inode, 0);	atomic_set(&inode->i_writecount, 0);	inode->i_size = 0;	inode->i_write_hint = WRITE_LIFE_NOT_SET;	inode->i_blocks = 0;	inode->i_bytes = 0;	inode->i_generation = 0;	inode->i_pipe = NULL;	inode->i_cdev = NULL;	inode->i_link = NULL;	inode->i_dir_seq = 0;	inode->i_rdev = 0;	inode->dirtied_when = 0; #ifdef CONFIG_CGROUP_WRITEBACK	inode->i_wb_frn_winner = 0;	inode->i_wb_frn_avg_time = 0;	inode->i_wb_frn_history = 0;#endif 	spin_lock_init(&inode->i_lock);	lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); 	init_rwsem(&inode->i_rwsem);	lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key); 	atomic_set(&inode->i_dio_count, 0); 	mapping->a_ops = &empty_aops;	mapping->host = inode;	mapping->flags = 0;	mapping->wb_err = 0;	atomic_set(&mapping->i_mmap_writable, 0);	mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);	mapping->writeback_index = 0;	init_rwsem(&mapping->invalidate_lock);	lockdep_set_class_and_name(&mapping->invalidate_lock,				   &sb->s_type->invalidate_lock_key,				   "mapping.invalidate_lock");	if (sb->s_iflags & SB_I_STABLE_WRITES)		mapping_set_stable_writes(mapping);	inode->i_private = NULL;	inode->i_mapping = mapping;	INIT_HLIST_HEAD(&inode->i_dentry);	/* buggered by rcu freeing */#ifdef CONFIG_FS_POSIX_ACL	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;#endif #ifdef CONFIG_FSNOTIFY	inode->i_fsnotify_mask = 0;#endif	inode->i_flctx = NULL; 	if (unlikely(security_inode_alloc(inode, gfp)))		return -ENOMEM; 	this_cpu_inc(nr_inodes); 	return 0;}EXPORT_SYMBOL(inode_init_always_gfp); void free_inode_nonrcu(struct inode *inode){	kmem_cache_free(inode_cachep, inode);}EXPORT_SYMBOL(free_inode_nonrcu); static void i_callback(struct rcu_head *head){	struct inode *inode = container_of(head, struct inode, i_rcu);	if (inode->free_inode)		inode->free_inode(inode);	else		free_inode_nonrcu(inode);} /** *	alloc_inode 	- obtain an inode *	@sb: superblock * *	Allocates a new inode for given superblock. *	Inode wont be chained in superblock s_inodes list *	This means : *	- fs can't be unmount *	- quotas, fsnotify, writeback can't work */struct inode *alloc_inode(struct super_block *sb){	const struct super_operations *ops = sb->s_op;	struct inode *inode; 	if (ops->alloc_inode)		inode = ops->alloc_inode(sb);	else		inode = alloc_inode_sb(sb, inode_cachep, GFP_KERNEL); 	if (!inode)		return NULL; 	if (unlikely(inode_init_always(sb, inode))) {		if (ops->destroy_inode) {			ops->destroy_inode(inode);			if (!ops->free_inode)				return NULL;		}		inode->free_inode = ops->free_inode;		i_callback(&inode->i_rcu);		return NULL;	} 	return inode;} void __destroy_inode(struct inode *inode){	inode_detach_wb(inode);	security_inode_free(inode);	fsnotify_inode_delete(inode);	locks_free_lock_context(inode);	if (!inode->i_nlink) {		WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);		atomic_long_dec(&inode->i_sb->s_remove_count);	} #ifdef CONFIG_FS_POSIX_ACL	if (inode->i_acl && !is_uncached_acl(inode->i_acl))		posix_acl_release(inode->i_acl);	if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl))		posix_acl_release(inode->i_default_acl);#endif	this_cpu_dec(nr_inodes);}EXPORT_SYMBOL(__destroy_inode); static void destroy_inode(struct inode *inode){	const struct super_operations *ops = inode->i_sb->s_op; 	BUG_ON(!list_empty(&inode->i_lru));	__destroy_inode(inode);	if (ops->destroy_inode) {		ops->destroy_inode(inode);		if (!ops->free_inode)			return;	}	inode->free_inode = ops->free_inode;	call_rcu(&inode->i_rcu, i_callback);} /** * drop_nlink - directly drop an inode's link count * @inode: inode * * This is a low-level filesystem helper to replace any * direct filesystem manipulation of i_nlink.  In cases * where we are attempting to track writes to the * filesystem, a decrement to zero means an imminent * write when the file is truncated and actually unlinked * on the filesystem. */void drop_nlink(struct inode *inode){	WARN_ON(inode->i_nlink == 0);	inode->__i_nlink--;	if (!inode->i_nlink)		atomic_long_inc(&inode->i_sb->s_remove_count);}EXPORT_SYMBOL(drop_nlink); /** * clear_nlink - directly zero an inode's link count * @inode: inode * * This is a low-level filesystem helper to replace any * direct filesystem manipulation of i_nlink.  See * drop_nlink() for why we care about i_nlink hitting zero. */void clear_nlink(struct inode *inode){	if (inode->i_nlink) {		inode->__i_nlink = 0;		atomic_long_inc(&inode->i_sb->s_remove_count);	}}EXPORT_SYMBOL(clear_nlink); /** * set_nlink - directly set an inode's link count * @inode: inode * @nlink: new nlink (should be non-zero) * * This is a low-level filesystem helper to replace any * direct filesystem manipulation of i_nlink. */void set_nlink(struct inode *inode, unsigned int nlink){	if (!nlink) {		clear_nlink(inode);	} else {		/* Yes, some filesystems do change nlink from zero to one */		if (inode->i_nlink == 0)			atomic_long_dec(&inode->i_sb->s_remove_count); 		inode->__i_nlink = nlink;	}}EXPORT_SYMBOL(set_nlink); /** * inc_nlink - directly increment an inode's link count * @inode: inode * * This is a low-level filesystem helper to replace any * direct filesystem manipulation of i_nlink.  Currently, * it is only here for parity with dec_nlink(). */void inc_nlink(struct inode *inode){	if (unlikely(inode->i_nlink == 0)) {		WARN_ON(!(inode_state_read_once(inode) & I_LINKABLE));		atomic_long_dec(&inode->i_sb->s_remove_count);	} 	inode->__i_nlink++;}EXPORT_SYMBOL(inc_nlink); static void __address_space_init_once(struct address_space *mapping){	xa_init_flags(&mapping->i_pages, XA_FLAGS_LOCK_IRQ | XA_FLAGS_ACCOUNT);	init_rwsem(&mapping->i_mmap_rwsem);	spin_lock_init(&mapping->i_private_lock);	mapping->i_mmap = RB_ROOT_CACHED;} void address_space_init_once(struct address_space *mapping){	memset(mapping, 0, sizeof(*mapping));	__address_space_init_once(mapping);}EXPORT_SYMBOL(address_space_init_once); /* * These are initializations that only need to be done * once, because the fields are idempotent across use * of the inode, so let the slab aware of that. */void inode_init_once(struct inode *inode){	memset(inode, 0, sizeof(*inode));	INIT_HLIST_NODE(&inode->i_hash);	INIT_LIST_HEAD(&inode->i_devices);	INIT_LIST_HEAD(&inode->i_io_list);	INIT_LIST_HEAD(&inode->i_wb_list);	INIT_LIST_HEAD(&inode->i_lru);

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