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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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); INIT_LIST_HEAD(&inode->i_sb_list); __address_space_init_once(&inode->i_data); i_size_ordered_init(inode);}EXPORT_SYMBOL(inode_init_once);
static void init_once(void *foo){ struct inode *inode = (struct inode *) foo;
inode_init_once(inode);}
struct wait_queue_head *inode_bit_waitqueue(struct wait_bit_queue_entry *wqe, struct inode *inode, u32 bit){ void *bit_address;
bit_address = inode_state_wait_address(inode, bit); init_wait_var_entry(wqe, bit_address, 0); return __var_waitqueue(bit_address);}EXPORT_SYMBOL(inode_bit_waitqueue);
void wait_on_new_inode(struct inode *inode){ struct wait_bit_queue_entry wqe; struct wait_queue_head *wq_head;
spin_lock(&inode->i_lock); if (!(inode_state_read(inode) & I_NEW)) { spin_unlock(&inode->i_lock); return; }
wq_head = inode_bit_waitqueue(&wqe, inode, __I_NEW); for (;;) { prepare_to_wait_event(wq_head, &wqe.wq_entry, TASK_UNINTERRUPTIBLE); if (!(inode_state_read(inode) & I_NEW)) break; spin_unlock(&inode->i_lock); schedule(); spin_lock(&inode->i_lock); } finish_wait(wq_head, &wqe.wq_entry); WARN_ON(inode_state_read(inode) & I_NEW); spin_unlock(&inode->i_lock);}EXPORT_SYMBOL(wait_on_new_inode);
static void __inode_lru_list_add(struct inode *inode, bool rotate){ lockdep_assert_held(&inode->i_lock);
if (inode_state_read(inode) & (I_DIRTY_ALL | I_SYNC | I_FREEING | I_WILL_FREE)) return; if (icount_read(inode)) return; if (!(inode->i_sb->s_flags & SB_ACTIVE)) return; if (!mapping_shrinkable(&inode->i_data)) return;
if (list_lru_add_obj(&inode->i_sb->s_inode_lru, &inode->i_lru)) this_cpu_inc(nr_unused); else if (rotate) inode_state_set(inode, I_REFERENCED);}
/* * Add inode to LRU if needed (inode is unused and clean). */void inode_lru_list_add(struct inode *inode){ __inode_lru_list_add(inode, false);}
static void inode_lru_list_del(struct inode *inode){ if (list_empty(&inode->i_lru)) return;
if (list_lru_del_obj(&inode->i_sb->s_inode_lru, &inode->i_lru)) this_cpu_dec(nr_unused);}
static void inode_pin_lru_isolating(struct inode *inode){ lockdep_assert_held(&inode->i_lock); WARN_ON(inode_state_read(inode) & (I_LRU_ISOLATING | I_FREEING | I_WILL_FREE)); inode_state_set(inode, I_LRU_ISOLATING);}
static void inode_unpin_lru_isolating(struct inode *inode){ spin_lock(&inode->i_lock); WARN_ON(!(inode_state_read(inode) & I_LRU_ISOLATING)); inode_state_clear(inode, I_LRU_ISOLATING); /* Called with inode->i_lock which ensures memory ordering. */ inode_wake_up_bit(inode, __I_LRU_ISOLATING); spin_unlock(&inode->i_lock);}
static void inode_wait_for_lru_isolating(struct inode *inode){ struct wait_bit_queue_entry wqe; struct wait_queue_head *wq_head;
lockdep_assert_held(&inode->i_lock); if (!(inode_state_read(inode) & I_LRU_ISOLATING)) return;
wq_head = inode_bit_waitqueue(&wqe, inode, __I_LRU_ISOLATING); for (;;) { prepare_to_wait_event(wq_head, &wqe.wq_entry, TASK_UNINTERRUPTIBLE); /* * Checking I_LRU_ISOLATING with inode->i_lock guarantees * memory ordering. */ if (!(inode_state_read(inode) & I_LRU_ISOLATING)) break; spin_unlock(&inode->i_lock); schedule(); spin_lock(&inode->i_lock); } finish_wait(wq_head, &wqe.wq_entry); WARN_ON(inode_state_read(inode) & I_LRU_ISOLATING);}
/** * inode_sb_list_add - add inode to the superblock list of inodes * @inode: inode to add */void inode_sb_list_add(struct inode *inode){ struct super_block *sb = inode->i_sb;
spin_lock(&sb->s_inode_list_lock); list_add(&inode->i_sb_list, &sb->s_inodes); spin_unlock(&sb->s_inode_list_lock);}EXPORT_SYMBOL_GPL(inode_sb_list_add);
static inline void inode_sb_list_del(struct inode *inode){ struct super_block *sb = inode->i_sb;
if (!list_empty(&inode->i_sb_list)) { spin_lock(&sb->s_inode_list_lock); list_del_init(&inode->i_sb_list); spin_unlock(&sb->s_inode_list_lock); }}
static unsigned long hash(struct super_block *sb, u64 hashval){ unsigned long tmp;
tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / L1_CACHE_BYTES; tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); return tmp & i_hash_mask;}
/** * __insert_inode_hash - hash an inode * @inode: unhashed inode * @hashval: u64 value used to locate this object in the * inode_hashtable. * * Add an inode to the inode hash for this superblock. */void __insert_inode_hash(struct inode *inode, u64 hashval){ struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
spin_lock(&inode_hash_lock); spin_lock(&inode->i_lock); hlist_add_head_rcu(&inode->i_hash, b); spin_unlock(&inode->i_lock); spin_unlock(&inode_hash_lock);}EXPORT_SYMBOL(__insert_inode_hash);
/** * __remove_inode_hash - remove an inode from the hash * @inode: inode to unhash * * Remove an inode from the superblock. */void __remove_inode_hash(struct inode *inode){ spin_lock(&inode_hash_lock); spin_lock(&inode->i_lock); hlist_del_init_rcu(&inode->i_hash); spin_unlock(&inode->i_lock); spin_unlock(&inode_hash_lock);}EXPORT_SYMBOL(__remove_inode_hash);
void dump_mapping(const struct address_space *mapping){ struct inode *host; const struct address_space_operations *a_ops; struct hlist_node *dentry_first; struct dentry *dentry_ptr; struct dentry dentry; char fname[64] = {}; u64 ino;
/* * If mapping is an invalid pointer, we don't want to crash * accessing it, so probe everything depending on it carefully. */ if (get_kernel_nofault(host, &mapping->host) || get_kernel_nofault(a_ops, &mapping->a_ops)) { pr_warn("invalid mapping:%px\n", mapping); return; }
if (!host) { pr_warn("aops:%ps\n", a_ops); return; }
if (get_kernel_nofault(dentry_first, &host->i_dentry.first) || get_kernel_nofault(ino, &host->i_ino)) { pr_warn("aops:%ps invalid inode:%px\n", a_ops, host); return; }
if (!dentry_first) { pr_warn("aops:%ps ino:%llx\n", a_ops, ino); return; }
dentry_ptr = container_of(dentry_first, struct dentry, d_alias); if (get_kernel_nofault(dentry, dentry_ptr) || !dentry.d_parent || !dentry.d_name.name) { pr_warn("aops:%ps ino:%llx invalid dentry:%px\n", a_ops, ino, dentry_ptr); return; }
if (strncpy_from_kernel_nofault(fname, dentry.d_name.name, 63) < 0) strscpy(fname, "<invalid>"); /* * Even if strncpy_from_kernel_nofault() succeeded, * the fname could be unreliable */ pr_warn("aops:%ps ino:%llx dentry name(?):\"%s\"\n", a_ops, ino, fname);}
void clear_inode(struct inode *inode){ /* * Only IS_VERITY() inodes can have verity info, so start by checking * for IS_VERITY() (which is faster than retrieving the pointer to the * verity info). This minimizes overhead for non-verity inodes. */ if (IS_ENABLED(CONFIG_FS_VERITY) && IS_VERITY(inode)) fsverity_cleanup_inode(inode);
/* * We have to cycle the i_pages lock here because reclaim can be in the * process of removing the last page (in __filemap_remove_folio()) * and we must not free the mapping under it. */ xa_lock_irq(&inode->i_data.i_pages); BUG_ON(inode->i_data.nrpages); /* * Almost always, mapping_empty(&inode->i_data) here; but there are * two known and long-standing ways in which nodes may get left behind * (when deep radix-tree node allocation failed partway; or when THP * collapse_file() failed). Until those two known cases are cleaned up, * or a cleanup function is called here, do not BUG_ON(!mapping_empty), * nor even WARN_ON(!mapping_empty). */ xa_unlock_irq(&inode->i_data.i_pages); BUG_ON(!(inode_state_read_once(inode) & I_FREEING)); BUG_ON(inode_state_read_once(inode) & I_CLEAR); BUG_ON(!list_empty(&inode->i_wb_list)); /* don't need i_lock here, no concurrent mods to i_state */ inode_state_assign_raw(inode, I_FREEING | I_CLEAR);}EXPORT_SYMBOL(clear_inode);
/* * Free the inode passed in, removing it from the lists it is still connected * to. We remove any pages still attached to the inode and wait for any IO that * is still in progress before finally destroying the inode. * * An inode must already be marked I_FREEING so that we avoid the inode being * moved back onto lists if we race with other code that manipulates the lists * (e.g. writeback_single_inode). The caller is responsible for setting this. * * An inode must already be removed from the LRU list before being evicted from * the cache. This should occur atomically with setting the I_FREEING state * flag, so no inodes here should ever be on the LRU when being evicted. */static void evict(struct inode *inode){ const struct super_operations *op = inode->i_sb->s_op;
BUG_ON(!(inode_state_read_once(inode) & I_FREEING)); BUG_ON(!list_empty(&inode->i_lru));
inode_io_list_del(inode); inode_sb_list_del(inode);
spin_lock(&inode->i_lock); inode_wait_for_lru_isolating(inode);
/* * Wait for flusher thread to be done with the inode so that filesystem * does not start destroying it while writeback is still running. Since * the inode has I_FREEING set, flusher thread won't start new work on * the inode. We just have to wait for running writeback to finish. */ inode_wait_for_writeback(inode); spin_unlock(&inode->i_lock);
if (op->evict_inode) { op->evict_inode(inode); } else { truncate_inode_pages_final(&inode->i_data); clear_inode(inode); } if (S_ISCHR(inode->i_mode) && inode->i_cdev) cd_forget(inode);
remove_inode_hash(inode);
/* * Wake up waiters in __wait_on_freeing_inode(). * * It is an invariant that any thread we need to wake up is already * accounted for before remove_inode_hash() acquires ->i_lock -- both * sides take the lock and sleep is aborted if the inode is found * unhashed. Thus either the sleeper wins and goes off CPU, or removal * wins and the sleeper aborts after testing with the lock. * * This also means we don't need any fences for the call below. */ inode_wake_up_bit(inode, __I_NEW); BUG_ON(inode_state_read_once(inode) != (I_FREEING | I_CLEAR));
destroy_inode(inode);}
/* * dispose_list - dispose of the contents of a local list * @head: the head of the list to free * * Dispose-list gets a local list with local inodes in it, so it doesn't * need to worry about list corruption and SMP locks. */static void dispose_list(struct list_head *head){ while (!list_empty(head)) { struct inode *inode;
inode = list_first_entry(head, struct inode, i_lru); list_del_init(&inode->i_lru);
evict(inode); cond_resched(); }}
/** * evict_inodes - evict all evictable inodes for a superblock * @sb: superblock to operate on * * Make sure that no inodes with zero refcount are retained. This is * called by superblock shutdown after having SB_ACTIVE flag removed, * so any inode reaching zero refcount during or after that call will * be immediately evicted. */void evict_inodes(struct super_block *sb){ struct inode *inode; LIST_HEAD(dispose);
again: spin_lock(&sb->s_inode_list_lock); list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { if (icount_read_once(inode)) continue;
spin_lock(&inode->i_lock); if (icount_read(inode)) { spin_unlock(&inode->i_lock); continue; } if (inode_state_read(inode) & (I_NEW | I_FREEING | I_WILL_FREE)) { spin_unlock(&inode->i_lock); continue; }
inode_state_set(inode, I_FREEING); inode_lru_list_del(inode); spin_unlock(&inode->i_lock); list_add(&inode->i_lru, &dispose);
/* * We can have a ton of inodes to evict at unmount time given * enough memory, check to see if we need to go to sleep for a * bit so we don't livelock. */ if (need_resched()) { spin_unlock(&sb->s_inode_list_lock); cond_resched(); dispose_list(&dispose); goto again; } } spin_unlock(&sb->s_inode_list_lock);
dispose_list(&dispose);}EXPORT_SYMBOL_GPL(evict_inodes);
/* * Isolate the inode from the LRU in preparation for freeing it. * * If the inode has the I_REFERENCED flag set, then it means that it has been * used recently - the flag is set in iput_final(). When we encounter such an * inode, clear the flag and move it to the back of the LRU so it gets another * pass through the LRU before it gets reclaimed. This is necessary because of * the fact we are doing lazy LRU updates to minimise lock contention so the * LRU does not have strict ordering. Hence we don't want to reclaim inodes * with this flag set because they are the inodes that are out of order. */static enum lru_status inode_lru_isolate(struct list_head *item, struct list_lru_one *lru, void *arg){ struct list_head *freeable = arg; struct inode *inode = container_of(item, struct inode, i_lru);
/* * We are inverting the lru lock/inode->i_lock here, so use a * trylock. If we fail to get the lock, just skip it. */ if (!spin_trylock(&inode->i_lock)) return LRU_SKIP;
/* * Inodes can get referenced, redirtied, or repopulated while * they're already on the LRU, and this can make them * unreclaimable for a while. Remove them lazily here; iput, * sync, or the last page cache deletion will requeue them. */ if (icount_read(inode) || (inode_state_read(inode) & ~I_REFERENCED) || !mapping_shrinkable(&inode->i_data)) { list_lru_isolate(lru, &inode->i_lru); spin_unlock(&inode->i_lock); this_cpu_dec(nr_unused); return LRU_REMOVED; }
/* Recently referenced inodes get one more pass */ if (inode_state_read(inode) & I_REFERENCED) { inode_state_clear(inode, I_REFERENCED); spin_unlock(&inode->i_lock); return LRU_ROTATE; }
/* * On highmem systems, mapping_shrinkable() permits dropping * page cache in order to free up struct inodes: lowmem might * be under pressure before the cache inside the highmem zone. */ if (!mapping_empty(&inode->i_data)) { unsigned long reap;
inode_pin_lru_isolating(inode); spin_unlock(&inode->i_lock); spin_unlock(&lru->lock); reap = invalidate_mapping_pages(&inode->i_data, 0, -1); if (current_is_kswapd()) __count_vm_events(KSWAPD_INODESTEAL, reap); else __count_vm_events(PGINODESTEAL, reap); mm_account_reclaimed_pages(reap); inode_unpin_lru_isolating(inode); return LRU_RETRY; }
WARN_ON(inode_state_read(inode) & I_NEW); inode_state_set(inode, I_FREEING); list_lru_isolate_move(lru, &inode->i_lru, freeable); spin_unlock(&inode->i_lock);
this_cpu_dec(nr_unused); return LRU_REMOVED;}
/* * Walk the superblock inode LRU for freeable inodes and attempt to free them. * This is called from the superblock shrinker function with a number of inodes * to trim from the LRU. Inodes to be freed are moved to a temporary list and * then are freed outside inode_lock by dispose_list(). */long prune_icache_sb(struct super_block *sb, struct shrink_control *sc){ LIST_HEAD(freeable); long freed;
freed = list_lru_shrink_walk(&sb->s_inode_lru, sc, inode_lru_isolate, &freeable); dispose_list(&freeable); return freed;}
static void __wait_on_freeing_inode(struct inode *inode, bool hash_locked, bool rcu_locked);static bool igrab_from_hash(struct inode *inode);
/* * Called with the inode lock held. */static struct inode *find_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data, bool hash_locked, bool *isnew){ struct inode *inode = NULL;
if (hash_locked) lockdep_assert_held(&inode_hash_lock); else lockdep_assert_not_held(&inode_hash_lock);
rcu_read_lock();repeat: hlist_for_each_entry_rcu(inode, head, i_hash) { if (inode->i_sb != sb) continue; if (!test(inode, data)) continue; if (igrab_from_hash(inode)) { rcu_read_unlock(); *isnew = false; return inode; } spin_lock(&inode->i_lock); if (inode_state_read(inode) & (I_FREEING | I_WILL_FREE)) { __wait_on_freeing_inode(inode, hash_locked, true); goto repeat; } if (unlikely(inode_state_read(inode) & I_CREATING)) { spin_unlock(&inode->i_lock); rcu_read_unlock(); return ERR_PTR(-ESTALE); } __iget(inode); *isnew = !!(inode_state_read(inode) & I_NEW); spin_unlock(&inode->i_lock); rcu_read_unlock(); return inode; } rcu_read_unlock(); return NULL;}
/* * find_inode_fast is the fast path version of find_inode, see the comment at * iget_locked for details. */static struct inode *find_inode_fast(struct super_block *sb, struct hlist_head *head, u64 ino, bool hash_locked, bool *isnew){ struct inode *inode = NULL;
if (hash_locked) lockdep_assert_held(&inode_hash_lock); else lockdep_assert_not_held(&inode_hash_lock);
rcu_read_lock();repeat: hlist_for_each_entry_rcu(inode, head, i_hash) { if (inode->i_ino != ino) continue; if (inode->i_sb != sb) continue; if (igrab_from_hash(inode)) { rcu_read_unlock(); *isnew = false; return inode; } spin_lock(&inode->i_lock); if (inode_state_read(inode) & (I_FREEING | I_WILL_FREE)) { __wait_on_freeing_inode(inode, hash_locked, true); goto repeat; } if (unlikely(inode_state_read(inode) & I_CREATING)) { spin_unlock(&inode->i_lock); rcu_read_unlock(); return ERR_PTR(-ESTALE); } __iget(inode); *isnew = !!(inode_state_read(inode) & I_NEW); spin_unlock(&inode->i_lock); rcu_read_unlock(); return inode; } rcu_read_unlock(); return NULL;}
/* * Each cpu owns a range of LAST_INO_BATCH numbers. * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, * to renew the exhausted range. * * This does not significantly increase overflow rate because every CPU can * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the * 2^32 range, and is a worst-case. Even a 50% wastage would only increase * overflow rate by 2x, which does not seem too significant. * * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW * error if st_ino won't fit in target struct field. Use 32bit counter * here to attempt to avoid that. */#define LAST_INO_BATCH 1024static DEFINE_PER_CPU(unsigned int, last_ino);
unsigned int get_next_ino(void){ unsigned int *p = &get_cpu_var(last_ino); unsigned int res = *p;
#ifdef CONFIG_SMP if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { static atomic_t shared_last_ino; int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
res = next - LAST_INO_BATCH; }#endif
res++; /* get_next_ino should not provide a 0 inode number */ if (unlikely(!res)) res++; *p = res; put_cpu_var(last_ino); return res;}EXPORT_SYMBOL(get_next_ino);
/** * new_inode - obtain an inode * @sb: superblock * * Allocates a new inode for given superblock. The default gfp_mask * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. * If HIGHMEM pages are unsuitable or it is known that pages allocated * for the page cache are not reclaimable or migratable, * mapping_set_gfp_mask() must be called with suitable flags on the * newly created inode's mapping * */struct inode *new_inode(struct super_block *sb){ struct inode *inode;
inode = alloc_inode(sb); if (inode) inode_sb_list_add(inode); return inode;}EXPORT_SYMBOL(new_inode);
#ifdef CONFIG_DEBUG_LOCK_ALLOCvoid lockdep_annotate_inode_mutex_key(struct inode *inode){ if (S_ISDIR(inode->i_mode)) { struct file_system_type *type = inode->i_sb->s_type;
/* Set new key only if filesystem hasn't already changed it */ if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) { /* * ensure nobody is actually holding i_rwsem */ init_rwsem(&inode->i_rwsem); lockdep_set_class(&inode->i_rwsem, &type->i_mutex_dir_key); } }}EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);#endif
/** * unlock_new_inode - clear the I_NEW state and wake up any waiters * @inode: new inode to unlock * * Called when the inode is fully initialised to clear the new state of the * inode and wake up anyone waiting for the inode to finish initialisation. */void unlock_new_inode(struct inode *inode){ lockdep_annotate_inode_mutex_key(inode); spin_lock(&inode->i_lock); WARN_ON(!(inode_state_read(inode) & I_NEW)); /* * Paired with igrab_from_hash() */ smp_wmb(); inode_state_clear(inode, I_NEW | I_CREATING); inode_wake_up_bit(inode, __I_NEW); spin_unlock(&inode->i_lock);}EXPORT_SYMBOL(unlock_new_inode);
void discard_new_inode(struct inode *inode){ lockdep_annotate_inode_mutex_key(inode); spin_lock(&inode->i_lock); WARN_ON(!(inode_state_read(inode) & I_NEW)); /* * Paired with igrab_from_hash() */ smp_wmb(); inode_state_clear(inode, I_NEW); inode_wake_up_bit(inode, __I_NEW); spin_unlock(&inode->i_lock); iput(inode);}EXPORT_SYMBOL(discard_new_inode);
/** * lock_two_nondirectories - take two i_mutexes on non-directory objects * * Lock any non-NULL argument. Passed objects must not be directories. * Zero, one or two objects may be locked by this function. * * @inode1: first inode to lock * @inode2: second inode to lock */void lock_two_nondirectories(struct inode *inode1, struct inode *inode2){ if (inode1) WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); if (inode2) WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); if (inode1 > inode2) swap(inode1, inode2); if (inode1) inode_lock(inode1); if (inode2 && inode2 != inode1) inode_lock_nested(inode2, I_MUTEX_NONDIR2);}EXPORT_SYMBOL(lock_two_nondirectories);
/** * unlock_two_nondirectories - release locks from lock_two_nondirectories() * @inode1: first inode to unlock * @inode2: second inode to unlock */void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2){ if (inode1) { WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); inode_unlock(inode1); } if (inode2 && inode2 != inode1) { WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); inode_unlock(inode2); }}EXPORT_SYMBOL(unlock_two_nondirectories);
/** * inode_insert5 - obtain an inode from a mounted file system * @inode: pre-allocated inode to use for insert to cache * @hashval: hash value (usually inode number) to get * @test: callback used for comparisons between inodes * @set: callback used to initialize a new struct inode * @data: opaque data pointer to pass to @test and @set * @isnew: pointer to a bool which will indicate whether I_NEW is set * * Search for the inode specified by @hashval and @data in the inode cache, * and if present return it with an increased reference count. This is a * variant of iget5_locked() that doesn't allocate an inode. * * If the inode is not present in the cache, insert the pre-allocated inode and * return it locked, hashed, and with the I_NEW flag set. The file system gets * to fill it in before unlocking it via unlock_new_inode(). * * Note that both @test and @set are called with the inode_hash_lock held, so * they can't sleep. */struct inode *inode_insert5(struct inode *inode, u64 hashval, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data){ struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); struct inode *old; bool isnew;
might_sleep();
again: spin_lock(&inode_hash_lock); old = find_inode(inode->i_sb, head, test, data, true, &isnew); if (unlikely(old)) { /* * Uhhuh, somebody else created the same inode under us. * Use the old inode instead of the preallocated one. */ spin_unlock(&inode_hash_lock); if (IS_ERR(old)) return NULL; if (unlikely(isnew)) wait_on_new_inode(old); if (unlikely(inode_unhashed(old))) { iput(old); goto again; } return old; }
if (set && unlikely(set(inode, data))) { spin_unlock(&inode_hash_lock); return NULL; }
/* * Return the locked inode with I_NEW set, the * caller is responsible for filling in the contents */ spin_lock(&inode->i_lock); inode_state_set(inode, I_NEW); hlist_add_head_rcu(&inode->i_hash, head); spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
/* * Add inode to the sb list if it's not already. It has I_NEW at this * point, so it should be safe to test i_sb_list locklessly. */ if (list_empty(&inode->i_sb_list)) inode_sb_list_add(inode);
return inode;}EXPORT_SYMBOL(inode_insert5);
/** * iget5_locked - obtain an inode from a mounted file system * @sb: super block of file system * @hashval: hash value (usually inode number) to get * @test: callback used for comparisons between inodes * @set: callback used to initialize a new struct inode * @data: opaque data pointer to pass to @test and @set * * Search for the inode specified by @hashval and @data in the inode cache, * and if present return it with an increased reference count. This is a * generalized version of iget_locked() for file systems where the inode * number is not sufficient for unique identification of an inode. * * If the inode is not present in the cache, allocate and insert a new inode * and return it locked, hashed, and with the I_NEW flag set. The file system * gets to fill it in before unlocking it via unlock_new_inode(). * * Note that both @test and @set are called with the inode_hash_lock held, so * they can't sleep. */struct inode *iget5_locked(struct super_block *sb, u64 hashval, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data){ struct inode *inode = ilookup5(sb, hashval, test, data);
if (!inode) { struct inode *new = alloc_inode(sb);
if (new) { inode = inode_insert5(new, hashval, test, set, data); if (unlikely(inode != new)) destroy_inode(new); } } return inode;}EXPORT_SYMBOL(iget5_locked);
/** * iget5_locked_rcu - obtain an inode from a mounted file system * @sb: super block of file system * @hashval: hash value (usually inode number) to get * @test: callback used for comparisons between inodes * @set: callback used to initialize a new struct inode * @data: opaque data pointer to pass to @test and @set * * This is equivalent to iget5_locked, except the @test callback must * tolerate the inode not being stable, including being mid-teardown. */struct inode *iget5_locked_rcu(struct super_block *sb, u64 hashval, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data){ struct hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode, *new; bool isnew;
might_sleep();
again: inode = find_inode(sb, head, test, data, false, &isnew); if (inode) { if (IS_ERR(inode)) return NULL; if (unlikely(isnew)) wait_on_new_inode(inode); if (unlikely(inode_unhashed(inode))) { iput(inode); goto again; } return inode; }
new = alloc_inode(sb); if (new) { inode = inode_insert5(new, hashval, test, set, data); if (unlikely(inode != new)) destroy_inode(new); } return inode;}EXPORT_SYMBOL_GPL(iget5_locked_rcu);
/** * iget_locked - obtain an inode from a mounted file system * @sb: super block of file system * @ino: inode number to get * * Search for the inode specified by @ino in the inode cache and if present * return it with an increased reference count. This is for file systems * where the inode number is sufficient for unique identification of an inode. * * If the inode is not in cache, allocate a new inode and return it locked, * hashed, and with the I_NEW flag set. The file system gets to fill it in * before unlocking it via unlock_new_inode(). */struct inode *iget_locked(struct super_block *sb, u64 ino){ struct hlist_head *head = inode_hashtable + hash(sb, ino); struct inode *inode; bool isnew;
might_sleep();
again: inode = find_inode_fast(sb, head, ino, false, &isnew); if (inode) { if (IS_ERR(inode)) return NULL; if (unlikely(isnew)) wait_on_new_inode(inode); if (unlikely(inode_unhashed(inode))) { iput(inode); goto again; } return inode; }
inode = alloc_inode(sb); if (inode) { struct inode *old;
spin_lock(&inode_hash_lock); /* We released the lock, so.. */ old = find_inode_fast(sb, head, ino, true, &isnew); if (!old) { inode->i_ino = ino; spin_lock(&inode->i_lock); inode_state_assign(inode, I_NEW); hlist_add_head_rcu(&inode->i_hash, head); spin_unlock(&inode->i_lock); spin_unlock(&inode_hash_lock); inode_sb_list_add(inode);
/* Return the locked inode with I_NEW set, the * caller is responsible for filling in the contents */ return inode; }
/* * Uhhuh, somebody else created the same inode under * us. Use the old inode instead of the one we just * allocated. */ spin_unlock(&inode_hash_lock); destroy_inode(inode); if (IS_ERR(old)) return NULL; inode = old; if (unlikely(isnew)) wait_on_new_inode(inode); if (unlikely(inode_unhashed(inode))) { iput(inode); goto again; } } return inode;}EXPORT_SYMBOL(iget_locked);
/* * search the inode cache for a matching inode number. * If we find one, then the inode number we are trying to * allocate is not unique and so we should not use it. * * Returns 1 if the inode number is unique, 0 if it is not. */static int test_inode_iunique(struct super_block *sb, u64 ino){ struct hlist_head *b = inode_hashtable + hash(sb, ino); struct inode *inode;
hlist_for_each_entry_rcu(inode, b, i_hash) { if (inode->i_ino == ino && inode->i_sb == sb) return 0; } return 1;}
/** * iunique - get a unique inode number * @sb: superblock * @max_reserved: highest reserved inode number * * Obtain an inode number that is unique on the system for a given * superblock. This is used by file systems that have no natural * permanent inode numbering system. An inode number is returned that * is higher than the reserved limit but unique. * * BUGS: * With a large number of inodes live on the file system this function * currently becomes quite slow. */ino_t iunique(struct super_block *sb, ino_t max_reserved){ /* * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW * error if st_ino won't fit in target struct field. Use 32bit counter * here to attempt to avoid that. */ static DEFINE_SPINLOCK(iunique_lock); static unsigned int counter; ino_t res;
rcu_read_lock(); spin_lock(&iunique_lock); do { if (counter <= max_reserved) counter = max_reserved + 1; res = counter++; } while (!test_inode_iunique(sb, res)); spin_unlock(&iunique_lock); rcu_read_unlock();
return res;}EXPORT_SYMBOL(iunique);
/** * ihold - get a reference on the inode, provided you already have one * @inode: inode to operate on */void ihold(struct inode *inode){ VFS_BUG_ON_INODE(icount_read_once(inode) < 1, inode); WARN_ON(atomic_inc_return(&inode->i_count) < 2);}EXPORT_SYMBOL(ihold);
struct inode *igrab(struct inode *inode){ /* * Read commentary above igrab_from_hash() for an explanation why this works. */ if (atomic_add_unless(&inode->i_count, 1, 0)) { VFS_BUG_ON_INODE(inode_state_read_once(inode) & (I_FREEING | I_WILL_FREE), inode); return inode; }
spin_lock(&inode->i_lock); if (!(inode_state_read(inode) & (I_FREEING | I_WILL_FREE))) { __iget(inode); spin_unlock(&inode->i_lock); } else { spin_unlock(&inode->i_lock); /* * Handle the case where s_op->clear_inode is not been * called yet, and somebody is calling igrab * while the inode is getting freed. */ inode = NULL; } return inode;}EXPORT_SYMBOL(igrab);
/* * igrab_from_hash - special inode refcount acquire primitive for the inode hash * * It provides lockless refcount acquire in the common case of no problematic * flags being set and the count being > 0. * * There are 4 state flags to worry about and the routine makes sure to not bump the * ref if any of them is present. * * I_NEW and I_CREATING can only legally get set *before* the inode becomes visible * during lookup. Thus if the flags are not spotted, they are guaranteed to not be * a factor. However, we need an acquire fence before returning the inode just * in case we raced against clearing the state to make sure our consumer picks up * any other changes made prior. atomic_add_unless provides a full fence, which * takes care of it. * * I_FREEING and I_WILL_FREE can only legally get set if ->i_count == 0 and it is * illegal to bump the ref if either is present. Consequently if atomic_add_unless * managed to replace a non-0 value with a bigger one, we have a guarantee neither * of these flags is set. Note this means explicitly checking of these flags below * is not necessary, it is only done because it does not cost anything on top of the * load which already needs to be done to handle the other flags. */static bool igrab_from_hash(struct inode *inode){ if (inode_state_read_once(inode) & (I_NEW | I_CREATING | I_FREEING | I_WILL_FREE)) return false; /* * Paired with routines clearing I_NEW */ if (atomic_add_unless(&inode->i_count, 1, 0)) { VFS_BUG_ON_INODE(inode_state_read_once(inode) & (I_FREEING | I_WILL_FREE), inode); return true; } return false;}
/** * ilookup5_nowait - search for an inode in the inode cache * @sb: super block of file system to search * @hashval: hash value (usually inode number) to search for * @test: callback used for comparisons between inodes * @data: opaque data pointer to pass to @test * @isnew: return argument telling whether I_NEW was set when * the inode was found in hash (the caller needs to * wait for I_NEW to clear) * * Search for the inode specified by @hashval and @data in the inode cache. * If the inode is in the cache, the inode is returned with an incremented * reference count. * * Note: I_NEW is not waited upon so you have to be very careful what you do * with the returned inode. You probably should be using ilookup5() instead. * * Note2: @test is called with the inode_hash_lock held, so can't sleep. */struct inode *ilookup5_nowait(struct super_block *sb, u64 hashval, int (*test)(struct inode *, void *), void *data, bool *isnew){ struct hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode;
spin_lock(&inode_hash_lock); inode = find_inode(sb, head, test, data, true, isnew); spin_unlock(&inode_hash_lock);
return IS_ERR(inode) ? NULL : inode;}EXPORT_SYMBOL(ilookup5_nowait);
/** * ilookup5 - search for an inode in the inode cache * @sb: super block of file system to search * @hashval: hash value (usually inode number) to search for * @test: callback used for comparisons between inodes * @data: opaque data pointer to pass to @test * * Search for the inode specified by @hashval and @data in the inode cache, * and if the inode is in the cache, return the inode with an incremented * reference count. Waits on I_NEW before returning the inode. * returned with an incremented reference count. * * This is a generalized version of ilookup() for file systems where the * inode number is not sufficient for unique identification of an inode. * * Note: @test is called with the inode_hash_lock held, so can't sleep. */struct inode *ilookup5(struct super_block *sb, u64 hashval, int (*test)(struct inode *, void *), void *data){ struct inode *inode; bool isnew;
might_sleep();
again: inode = ilookup5_nowait(sb, hashval, test, data, &isnew); if (inode) { if (unlikely(isnew)) wait_on_new_inode(inode); if (unlikely(inode_unhashed(inode))) { iput(inode); goto again; } } return inode;}EXPORT_SYMBOL(ilookup5);
/** * ilookup - search for an inode in the inode cache * @sb: super block of file system to search * @ino: inode number to search for * * Search for the inode @ino in the inode cache, and if the inode is in the * cache, the inode is returned with an incremented reference count. */struct inode *ilookup(struct super_block *sb, u64 ino){ struct hlist_head *head = inode_hashtable + hash(sb, ino); struct inode *inode; bool isnew;
might_sleep();
again: inode = find_inode_fast(sb, head, ino, false, &isnew);
if (inode) { if (IS_ERR(inode)) return NULL; if (unlikely(isnew)) wait_on_new_inode(inode); if (unlikely(inode_unhashed(inode))) { iput(inode); goto again; } } return inode;}EXPORT_SYMBOL(ilookup);
/** * find_inode_nowait - find an inode in the inode cache * @sb: super block of file system to search * @hashval: hash value (usually inode number) to search for * @match: callback used for comparisons between inodes * @data: opaque data pointer to pass to @match * * Search for the inode specified by @hashval and @data in the inode * cache, where the helper function @match will return 0 if the inode * does not match, 1 if the inode does match, and -1 if the search * should be stopped. The @match function must be responsible for * taking the i_lock spin_lock and checking i_state for an inode being * freed or being initialized, and incrementing the reference count * before returning 1. It also must not sleep, since it is called with * the inode_hash_lock spinlock held. * * This is a even more generalized version of ilookup5() when the * function must never block --- find_inode() can block in * __wait_on_freeing_inode() --- or when the caller can not increment * the reference count because the resulting iput() might cause an * inode eviction. The tradeoff is that the @match funtion must be * very carefully implemented. */struct inode *find_inode_nowait(struct super_block *sb, u64 hashval, int (*match)(struct inode *, u64, void *), void *data){ struct hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode, *ret_inode = NULL; int mval;
spin_lock(&inode_hash_lock); hlist_for_each_entry(inode, head, i_hash) { if (inode->i_sb != sb) continue; mval = match(inode, hashval, data); if (mval == 0) continue; if (mval == 1) ret_inode = inode; goto out; }out: spin_unlock(&inode_hash_lock); return ret_inode;}EXPORT_SYMBOL(find_inode_nowait);
/** * find_inode_rcu - find an inode in the inode cache * @sb: Super block of file system to search * @hashval: Key to hash * @test: Function to test match on an inode * @data: Data for test function * * Search for the inode specified by @hashval and @data in the inode cache, * where the helper function @test will return 0 if the inode does not match * and 1 if it does. The @test function must be responsible for taking the * i_lock spin_lock and checking i_state for an inode being freed or being * initialized. * * If successful, this will return the inode for which the @test function * returned 1 and NULL otherwise. * * The @test function is not permitted to take a ref on any inode presented. * It is also not permitted to sleep. * * The caller must hold the RCU read lock. */struct inode *find_inode_rcu(struct super_block *sb, u64 hashval, int (*test)(struct inode *, void *), void *data){ struct hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode;
RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "suspicious find_inode_rcu() usage");
hlist_for_each_entry_rcu(inode, head, i_hash) { if (inode->i_sb == sb && !(inode_state_read_once(inode) & (I_FREEING | I_WILL_FREE)) && test(inode, data)) return inode; } return NULL;}EXPORT_SYMBOL(find_inode_rcu);
/** * find_inode_by_ino_rcu - Find an inode in the inode cache * @sb: Super block of file system to search * @ino: The inode number to match * * Search for the inode specified by @hashval and @data in the inode cache, * where the helper function @test will return 0 if the inode does not match * and 1 if it does. The @test function must be responsible for taking the * i_lock spin_lock and checking i_state for an inode being freed or being * initialized. * * If successful, this will return the inode for which the @test function * returned 1 and NULL otherwise. * * The @test function is not permitted to take a ref on any inode presented. * It is also not permitted to sleep. * * The caller must hold the RCU read lock. */struct inode *find_inode_by_ino_rcu(struct super_block *sb, u64 ino){ struct hlist_head *head = inode_hashtable + hash(sb, ino); struct inode *inode;
RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "suspicious find_inode_by_ino_rcu() usage");
hlist_for_each_entry_rcu(inode, head, i_hash) { if (inode->i_ino == ino && inode->i_sb == sb && !(inode_state_read_once(inode) & (I_FREEING | I_WILL_FREE))) return inode; } return NULL;}EXPORT_SYMBOL(find_inode_by_ino_rcu);
int insert_inode_locked(struct inode *inode){ struct super_block *sb = inode->i_sb; u64 ino = inode->i_ino; struct hlist_head *head = inode_hashtable + hash(sb, ino); bool isnew;
might_sleep();
while (1) { struct inode *old = NULL; spin_lock(&inode_hash_lock);repeat: hlist_for_each_entry(old, head, i_hash) { if (old->i_ino != ino) continue; if (old->i_sb != sb) continue; spin_lock(&old->i_lock); break; } if (likely(!old)) { spin_lock(&inode->i_lock); inode_state_set(inode, I_NEW | I_CREATING); hlist_add_head_rcu(&inode->i_hash, head); spin_unlock(&inode->i_lock); spin_unlock(&inode_hash_lock); return 0; } if (inode_state_read(old) & (I_FREEING | I_WILL_FREE)) { __wait_on_freeing_inode(old, true, false); old = NULL; goto repeat; } if (unlikely(inode_state_read(old) & I_CREATING)) { spin_unlock(&old->i_lock); spin_unlock(&inode_hash_lock); return -EBUSY; } __iget(old); isnew = !!(inode_state_read(old) & I_NEW); spin_unlock(&old->i_lock); spin_unlock(&inode_hash_lock); if (isnew) wait_on_new_inode(old); if (unlikely(!inode_unhashed(old))) { iput(old); return -EBUSY; } iput(old); }}EXPORT_SYMBOL(insert_inode_locked);
int insert_inode_locked4(struct inode *inode, u64 hashval, int (*test)(struct inode *, void *), void *data){ struct inode *old;
might_sleep();
inode_state_set_raw(inode, I_CREATING); old = inode_insert5(inode, hashval, test, NULL, data);
if (old != inode) { iput(old); return -EBUSY; } return 0;}EXPORT_SYMBOL(insert_inode_locked4);
int inode_just_drop(struct inode *inode){ return 1;}EXPORT_SYMBOL(inode_just_drop);
/* * Called when we're dropping the last reference * to an inode. * * Call the FS "drop_inode()" function, defaulting to * the legacy UNIX filesystem behaviour. If it tells * us to evict inode, do so. Otherwise, retain inode * in cache if fs is alive, sync and evict if fs is * shutting down. */static void iput_final(struct inode *inode){ struct super_block *sb = inode->i_sb; const struct super_operations *op = inode->i_sb->s_op; int drop;
WARN_ON(inode_state_read(inode) & I_NEW); VFS_BUG_ON_INODE(icount_read(inode) != 0, inode);
if (op->drop_inode) drop = op->drop_inode(inode); else drop = inode_generic_drop(inode);
if (!drop && !(inode_state_read(inode) & I_DONTCACHE) && (sb->s_flags & SB_ACTIVE)) { __inode_lru_list_add(inode, true); spin_unlock(&inode->i_lock); return; }
/* * Re-check ->i_count in case the ->drop_inode() hooks played games. * Note we only execute this if the verdict was to drop the inode. */ VFS_BUG_ON_INODE(icount_read(inode) != 0, inode);
if (drop) { inode_state_set(inode, I_FREEING); } else { inode_state_set(inode, I_WILL_FREE); spin_unlock(&inode->i_lock);
write_inode_now(inode, 1);
spin_lock(&inode->i_lock); WARN_ON(inode_state_read(inode) & I_NEW); inode_state_replace(inode, I_WILL_FREE, I_FREEING); }
inode_lru_list_del(inode); spin_unlock(&inode->i_lock);
evict(inode);}
/** * iput - put an inode * @inode: inode to put * * Puts an inode, dropping its usage count. If the inode use count hits * zero, the inode is then freed and may also be destroyed. * * Consequently, iput() can sleep. */void iput(struct inode *inode){ might_sleep(); if (unlikely(!inode)) return;
retry: lockdep_assert_not_held(&inode->i_lock); VFS_BUG_ON_INODE(inode_state_read_once(inode) & (I_FREEING | I_CLEAR), inode); /* * Note this assert is technically racy as if the count is bogusly * equal to one, then two CPUs racing to further drop it can both * conclude it's fine. */ VFS_BUG_ON_INODE(icount_read_once(inode) < 1, inode);
if (atomic_add_unless(&inode->i_count, -1, 1)) return;
if (inode->i_nlink && sync_lazytime(inode)) goto retry;
spin_lock(&inode->i_lock); if (unlikely((inode_state_read(inode) & I_DIRTY_TIME) && inode->i_nlink)) { spin_unlock(&inode->i_lock); goto retry; }
if (!atomic_dec_and_test(&inode->i_count)) { spin_unlock(&inode->i_lock); return; }
/* * iput_final() drops ->i_lock, we can't assert on it as the inode may * be deallocated by the time the call returns. */ iput_final(inode);}EXPORT_SYMBOL(iput);
/** * iput_not_last - put an inode assuming this is not the last reference * @inode: inode to put */void iput_not_last(struct inode *inode){ VFS_BUG_ON_INODE(inode_state_read_once(inode) & (I_FREEING | I_CLEAR), inode); VFS_BUG_ON_INODE(icount_read_once(inode) < 2, inode);
WARN_ON(atomic_sub_return(1, &inode->i_count) == 0);}EXPORT_SYMBOL(iput_not_last);
#ifdef CONFIG_BLOCK/** * bmap - find a block number in a file * @inode: inode owning the block number being requested * @block: pointer containing the block to find * * Replaces the value in ``*block`` with the block number on the device holding * corresponding to the requested block number in the file. * That is, asked for block 4 of inode 1 the function will replace the * 4 in ``*block``, with disk block relative to the disk start that holds that * block of the file. * * Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a * hole, returns 0 and ``*block`` is also set to 0. */int bmap(struct inode *inode, sector_t *block){ if (!inode->i_mapping->a_ops->bmap) return -EINVAL;
*block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block); return 0;}EXPORT_SYMBOL(bmap);#endif
/* * With relative atime, only update atime if the previous atime is * earlier than or equal to either the ctime or mtime, * or if at least a day has passed since the last atime update. */static bool relatime_need_update(struct vfsmount *mnt, struct inode *inode, struct timespec64 now){ struct timespec64 atime, mtime, ctime;
if (!(mnt->mnt_flags & MNT_RELATIME)) return true; /* * Is mtime younger than or equal to atime? If yes, update atime: */ atime = inode_get_atime(inode); mtime = inode_get_mtime(inode); if (timespec64_compare(&mtime, &atime) >= 0) return true; /* * Is ctime younger than or equal to atime? If yes, update atime: */ ctime = inode_get_ctime(inode); if (timespec64_compare(&ctime, &atime) >= 0) return true;
/* * Is the previous atime value older than a day? If yes, * update atime: */ if ((long)(now.tv_sec - atime.tv_sec) >= 24*60*60) return true; /* * Good, we can skip the atime update: */ return false;}
static int inode_update_atime(struct inode *inode){ struct timespec64 atime = inode_get_atime(inode); struct timespec64 now = current_time(inode);
if (timespec64_equal(&now, &atime)) return 0;
inode_set_atime_to_ts(inode, now); return inode_time_dirty_flag(inode);}
static int inode_update_cmtime(struct inode *inode, unsigned int flags){ struct timespec64 ctime = inode_get_ctime(inode); struct timespec64 mtime = inode_get_mtime(inode); struct timespec64 now = inode_set_ctime_current(inode); unsigned int dirty = 0; bool mtime_changed;
mtime_changed = !timespec64_equal(&now, &mtime); if (mtime_changed || !timespec64_equal(&now, &ctime)) dirty = inode_time_dirty_flag(inode);
/* * Pure timestamp updates can be recorded in the inode without blocking * by not dirtying the inode. But when the file system requires * i_version updates, the update of i_version can still block. * Error out if we'd actually have to update i_version or don't support * lazytime. */ if (IS_I_VERSION(inode)) { if (flags & IOCB_NOWAIT) { if (!(inode->i_sb->s_flags & SB_LAZYTIME) || inode_iversion_need_inc(inode)) return -EAGAIN; } else { /* * Don't force iversion increment for pure lazytime * updates (I_DIRTY_TIME only), let I_VERSION_QUERIED * dictate whether the increment is needed. */ if (inode_maybe_inc_iversion(inode, dirty != I_DIRTY_TIME)) dirty |= I_DIRTY_SYNC; } }
if (mtime_changed) inode_set_mtime_to_ts(inode, now); return dirty;}
/** * inode_update_time - update either atime or c/mtime and i_version on the inode * @inode: inode to be updated * @type: timestamp to be updated * @flags: flags for the update * * Update either atime or c/mtime and version in a inode if needed for a file * access or modification. It is up to the caller to mark the inode dirty * appropriately. * * Returns the positive I_DIRTY_* flags for __mark_inode_dirty() if the inode * needs to be marked dirty, 0 if it did not, or a negative errno if an error * happened. */int inode_update_time(struct inode *inode, enum fs_update_time type, unsigned int flags){ switch (type) { case FS_UPD_ATIME: return inode_update_atime(inode); case FS_UPD_CMTIME: return inode_update_cmtime(inode, flags); default: WARN_ON_ONCE(1); return -EIO; }}EXPORT_SYMBOL(inode_update_time);
/** * generic_update_time - update the timestamps on the inode * @inode: inode to be updated * @type: timestamp to be updated * @flags: flags for the update * * Returns a negative error value on error, else 0. */int generic_update_time(struct inode *inode, enum fs_update_time type, unsigned int flags){ int dirty;
/* * ->dirty_inode is what could make generic timestamp updates block. * Don't support non-blocking timestamp updates here if it is set. * File systems that implement ->dirty_inode but want to support * non-blocking timestamp updates should call inode_update_time * directly. */ if ((flags & IOCB_NOWAIT) && inode->i_sb->s_op->dirty_inode) return -EAGAIN;
dirty = inode_update_time(inode, type, flags); if (dirty <= 0) return dirty; __mark_inode_dirty(inode, dirty); return 0;}EXPORT_SYMBOL(generic_update_time);
/** * atime_needs_update - update the access time * @path: the &struct path to update * @inode: inode to update * * Update the accessed time on an inode and mark it for writeback. * This function automatically handles read only file systems and media, * as well as the "noatime" flag and inode specific "noatime" markers. */bool atime_needs_update(const struct path *path, struct inode *inode){ struct vfsmount *mnt = path->mnt; struct timespec64 now, atime;
if (inode->i_flags & S_NOATIME) return false;
/* Atime updates will likely cause i_uid and i_gid to be written * back improprely if their true value is unknown to the vfs. */ if (HAS_UNMAPPED_ID(mnt_idmap(mnt), inode)) return false;
if (IS_NOATIME(inode)) return false; if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode)) return false;
if (mnt->mnt_flags & MNT_NOATIME) return false; if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) return false;
now = current_time(inode);
if (!relatime_need_update(mnt, inode, now)) return false;
atime = inode_get_atime(inode); if (timespec64_equal(&atime, &now)) return false;
return true;}
void touch_atime(const struct path *path){ struct vfsmount *mnt = path->mnt; struct inode *inode = d_inode(path->dentry);
if (!atime_needs_update(path, inode)) return;
if (!sb_start_write_trylock(inode->i_sb)) return;
if (mnt_get_write_access(mnt) != 0) goto skip_update; /* * File systems can error out when updating inodes if they need to * allocate new space to modify an inode (such is the case for * Btrfs), but since we touch atime while walking down the path we * really don't care if we failed to update the atime of the file, * so just ignore the return value. * We may also fail on filesystems that have the ability to make parts * of the fs read only, e.g. subvolumes in Btrfs. */ if (inode->i_op->update_time) inode->i_op->update_time(inode, FS_UPD_ATIME, 0); else generic_update_time(inode, FS_UPD_ATIME, 0); mnt_put_write_access(mnt);skip_update: sb_end_write(inode->i_sb);}EXPORT_SYMBOL(touch_atime);
/* * Return mask of changes for notify_change() that need to be done as a * response to write or truncate. Return 0 if nothing has to be changed. * Negative value on error (change should be denied). */int dentry_needs_remove_privs(struct mnt_idmap *idmap, struct dentry *dentry){ struct inode *inode = d_inode(dentry); int mask = 0; int ret;
if (IS_NOSEC(inode)) return 0;
mask = setattr_should_drop_suidgid(idmap, inode); ret = security_inode_need_killpriv(dentry); if (ret < 0) return ret; if (ret) mask |= ATTR_KILL_PRIV; return mask;}
static int __remove_privs(struct mnt_idmap *idmap, struct dentry *dentry, int kill){ struct iattr newattrs;
newattrs.ia_valid = ATTR_FORCE | kill; /* * Note we call this on write, so notify_change will not * encounter any conflicting delegations: */ return notify_change(idmap, dentry, &newattrs, NULL);}
static int file_remove_privs_flags(struct file *file, unsigned int flags){ struct dentry *dentry = file_dentry(file); struct inode *inode = file_inode(file); int error = 0; int kill;
if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode)) return 0;
kill = dentry_needs_remove_privs(file_mnt_idmap(file), dentry); if (kill < 0) return kill;
if (kill) { if (flags & IOCB_NOWAIT) return -EAGAIN;
error = __remove_privs(file_mnt_idmap(file), dentry, kill); }
if (!error) inode_has_no_xattr(inode); return error;}
/** * file_remove_privs - remove special file privileges (suid, capabilities) * @file: file to remove privileges from * * When file is modified by a write or truncation ensure that special * file privileges are removed. * * Return: 0 on success, negative errno on failure. */int file_remove_privs(struct file *file){ return file_remove_privs_flags(file, 0);}EXPORT_SYMBOL(file_remove_privs);
/** * current_time - Return FS time (possibly fine-grained) * @inode: inode. * * Return the current time truncated to the time granularity supported by * the fs, as suitable for a ctime/mtime change. If the ctime is flagged * as having been QUERIED, get a fine-grained timestamp, but don't update * the floor. * * For a multigrain inode, this is effectively an estimate of the timestamp * that a file would receive. An actual update must go through * inode_set_ctime_current(). */struct timespec64 current_time(struct inode *inode){ struct timespec64 now; u32 cns;
ktime_get_coarse_real_ts64_mg(&now);
if (!is_mgtime(inode)) goto out;
/* If nothing has queried it, then coarse time is fine */ cns = smp_load_acquire(&inode->i_ctime_nsec); if (cns & I_CTIME_QUERIED) { /* * If there is no apparent change, then get a fine-grained * timestamp. */ if (now.tv_nsec == (cns & ~I_CTIME_QUERIED)) ktime_get_real_ts64(&now); }out: return timestamp_truncate(now, inode);}EXPORT_SYMBOL(current_time);
static inline bool need_cmtime_update(struct inode *inode){ struct timespec64 now = current_time(inode), ts;
ts = inode_get_mtime(inode); if (!timespec64_equal(&ts, &now)) return true; ts = inode_get_ctime(inode); if (!timespec64_equal(&ts, &now)) return true; return IS_I_VERSION(inode) && inode_iversion_need_inc(inode);}
static int file_update_time_flags(struct file *file, unsigned int flags){ struct inode *inode = file_inode(file); int ret;
/* First try to exhaust all avenues to not sync */ if (IS_NOCMTIME(inode)) return 0; if (unlikely(file->f_mode & FMODE_NOCMTIME)) return 0; if (!need_cmtime_update(inode)) return 0;
flags &= IOCB_NOWAIT; if (mnt_get_write_access_file(file)) return 0; if (inode->i_op->update_time) ret = inode->i_op->update_time(inode, FS_UPD_CMTIME, flags); else ret = generic_update_time(inode, FS_UPD_CMTIME, flags); mnt_put_write_access_file(file); return ret;}
/** * file_update_time - update mtime and ctime time * @file: file accessed * * Update the mtime and ctime members of an inode and mark the inode for * writeback. Note that this function is meant exclusively for usage in * the file write path of filesystems, and filesystems may choose to * explicitly ignore updates via this function with the _NOCMTIME inode * flag, e.g. for network filesystem where these imestamps are handled * by the server. This can return an error for file systems who need to * allocate space in order to update an inode. * * Return: 0 on success, negative errno on failure. */int file_update_time(struct file *file){ return file_update_time_flags(file, 0);}EXPORT_SYMBOL(file_update_time);
/** * file_modified_flags - handle mandated vfs changes when modifying a file * @file: file that was modified * @flags: kiocb flags * * When file has been modified ensure that special * file privileges are removed and time settings are updated. * * If IOCB_NOWAIT is set, special file privileges will not be removed and * time settings will not be updated. It will return -EAGAIN. * * Context: Caller must hold the file's inode lock. * * Return: 0 on success, negative errno on failure. */static int file_modified_flags(struct file *file, int flags){ int ret;
/* * Clear the security bits if the process is not being run by root. * This keeps people from modifying setuid and setgid binaries. */ ret = file_remove_privs_flags(file, flags); if (ret) return ret; return file_update_time_flags(file, flags);}
/** * file_modified - handle mandated vfs changes when modifying a file * @file: file that was modified * * When file has been modified ensure that special * file privileges are removed and time settings are updated. * * Context: Caller must hold the file's inode lock. * * Return: 0 on success, negative errno on failure. */int file_modified(struct file *file){ return file_modified_flags(file, 0);}EXPORT_SYMBOL(file_modified);
/** * kiocb_modified - handle mandated vfs changes when modifying a file * @iocb: iocb that was modified * * When file has been modified ensure that special * file privileges are removed and time settings are updated. * * Context: Caller must hold the file's inode lock. * * Return: 0 on success, negative errno on failure. */int kiocb_modified(struct kiocb *iocb){ return file_modified_flags(iocb->ki_filp, iocb->ki_flags);}EXPORT_SYMBOL_GPL(kiocb_modified);
int inode_needs_sync(struct inode *inode){ if (IS_SYNC(inode)) return 1; if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) return 1; return 0;}EXPORT_SYMBOL(inode_needs_sync);
/* * If we try to find an inode in the inode hash while it is being * deleted, we have to wait until the filesystem completes its * deletion before reporting that it isn't found. This function waits * until the deletion _might_ have completed. Callers are responsible * to recheck inode state. * * It doesn't matter if I_NEW is not set initially, a call to * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list * will DTRT. */static void __wait_on_freeing_inode(struct inode *inode, bool hash_locked, bool rcu_locked){ struct wait_bit_queue_entry wqe; struct wait_queue_head *wq_head;
VFS_BUG_ON(!hash_locked && !rcu_locked);
/* * Handle racing against evict(), see that routine for more details. */ if (unlikely(inode_unhashed(inode))) { WARN_ON(hash_locked); spin_unlock(&inode->i_lock); return; }
wq_head = inode_bit_waitqueue(&wqe, inode, __I_NEW); prepare_to_wait_event(wq_head, &wqe.wq_entry, TASK_UNINTERRUPTIBLE); spin_unlock(&inode->i_lock); if (rcu_locked) rcu_read_unlock(); if (hash_locked) spin_unlock(&inode_hash_lock); schedule(); finish_wait(wq_head, &wqe.wq_entry); if (hash_locked) spin_lock(&inode_hash_lock); if (rcu_locked) rcu_read_lock();}
static __initdata unsigned long ihash_entries;static int __init set_ihash_entries(char *str){ return kstrtoul(str, 0, &ihash_entries) == 0;}__setup("ihash_entries=", set_ihash_entries);
/* * Initialize the waitqueues and inode hash table. */void __init inode_init_early(void){ /* If hashes are distributed across NUMA nodes, defer * hash allocation until vmalloc space is available. */ if (hashdist) return;
inode_hashtable = alloc_large_system_hash("Inode-cache", sizeof(struct hlist_head), ihash_entries, 14, HASH_EARLY | HASH_ZERO, &i_hash_shift, &i_hash_mask, 0, 0);}
void __init inode_init(void){ /* inode slab cache */ inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode), 0, (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| SLAB_ACCOUNT), init_once);
/* Hash may have been set up in inode_init_early */ if (!hashdist) return;
inode_hashtable = alloc_large_system_hash("Inode-cache", sizeof(struct hlist_head), ihash_entries, 14, HASH_ZERO, &i_hash_shift, &i_hash_mask, 0, 0);}
void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev){ inode->i_mode = mode; switch (inode->i_mode & S_IFMT) { case S_IFCHR: inode->i_fop = &def_chr_fops; inode->i_rdev = rdev; break; case S_IFBLK: if (IS_ENABLED(CONFIG_BLOCK)) inode->i_fop = &def_blk_fops; inode->i_rdev = rdev; break; case S_IFIFO: inode->i_fop = &pipefifo_fops; break; case S_IFSOCK: /* leave it no_open_fops */ break; default: pr_debug("init_special_inode: bogus i_mode (%o) for inode %s:%llu\n", mode, inode->i_sb->s_id, inode->i_ino); break; }}EXPORT_SYMBOL(init_special_inode);
/** * inode_init_owner - Init uid,gid,mode for new inode according to posix standards * @idmap: idmap of the mount the inode was created from * @inode: New inode * @dir: Directory inode * @mode: mode of the new inode * * If the inode has been created through an idmapped mount the idmap of * the vfsmount must be passed through @idmap. This function will then take * care to map the inode according to @idmap before checking permissions * and initializing i_uid and i_gid. On non-idmapped mounts or if permission * checking is to be performed on the raw inode simply pass @nop_mnt_idmap. */void inode_init_owner(struct mnt_idmap *idmap, struct inode *inode, const struct inode *dir, umode_t mode){ inode_fsuid_set(inode, idmap); if (dir && dir->i_mode & S_ISGID) { inode->i_gid = dir->i_gid;
/* Directories are special, and always inherit S_ISGID */ if (S_ISDIR(mode)) mode |= S_ISGID; } else inode_fsgid_set(inode, idmap); inode->i_mode = mode;}EXPORT_SYMBOL(inode_init_owner);
/** * inode_owner_or_capable - check current task permissions to inode * @idmap: idmap of the mount the inode was found from * @inode: inode being checked * * Return true if current either has CAP_FOWNER in a namespace with the * inode owner uid mapped, or owns the file. * * If the inode has been found through an idmapped mount the idmap of * the vfsmount must be passed through @idmap. This function will then take * care to map the inode according to @idmap before checking permissions. * On non-idmapped mounts or if permission checking is to be performed on the * raw inode simply pass @nop_mnt_idmap. */bool inode_owner_or_capable(struct mnt_idmap *idmap, const struct inode *inode){ vfsuid_t vfsuid; struct user_namespace *ns;
vfsuid = i_uid_into_vfsuid(idmap, inode); if (vfsuid_eq_kuid(vfsuid, current_fsuid())) return true;
ns = current_user_ns(); if (vfsuid_has_mapping(ns, vfsuid) && ns_capable(ns, CAP_FOWNER)) return true; return false;}EXPORT_SYMBOL(inode_owner_or_capable);
/* * Direct i/o helper functions */bool inode_dio_finished(const struct inode *inode){ return atomic_read(&inode->i_dio_count) == 0;}EXPORT_SYMBOL(inode_dio_finished);
/** * inode_dio_wait - wait for outstanding DIO requests to finish * @inode: inode to wait for * * Waits for all pending direct I/O requests to finish so that we can * proceed with a truncate or equivalent operation. * * Must be called under a lock that serializes taking new references * to i_dio_count, usually by inode->i_rwsem. */void inode_dio_wait(struct inode *inode){ wait_var_event(&inode->i_dio_count, inode_dio_finished(inode));}EXPORT_SYMBOL(inode_dio_wait);
void inode_dio_wait_interruptible(struct inode *inode){ wait_var_event_interruptible(&inode->i_dio_count, inode_dio_finished(inode));}EXPORT_SYMBOL(inode_dio_wait_interruptible);
/* * inode_set_flags - atomically set some inode flags * * Note: the caller should be holding i_rwsem exclusively, or else be sure that * they have exclusive access to the inode structure (i.e., while the * inode is being instantiated). The reason for the cmpxchg() loop * --- which wouldn't be necessary if all code paths which modify * i_flags actually followed this rule, is that there is at least one * code path which doesn't today so we use cmpxchg() out of an abundance * of caution. * * In the long run, i_rwsem is overkill, and we should probably look * at using the i_lock spinlock to protect i_flags, and then make sure * it is so documented in include/linux/fs.h and that all code follows * the locking convention!! */void inode_set_flags(struct inode *inode, unsigned int flags, unsigned int mask){ WARN_ON_ONCE(flags & ~mask); set_mask_bits(&inode->i_flags, mask, flags);}EXPORT_SYMBOL(inode_set_flags);
void inode_nohighmem(struct inode *inode){ mapping_set_gfp_mask(inode->i_mapping, GFP_USER);}EXPORT_SYMBOL(inode_nohighmem);
struct timespec64 inode_set_ctime_to_ts(struct inode *inode, struct timespec64 ts){ trace_inode_set_ctime_to_ts(inode, &ts); set_normalized_timespec64(&ts, ts.tv_sec, ts.tv_nsec); inode->i_ctime_sec = ts.tv_sec; inode->i_ctime_nsec = ts.tv_nsec; return ts;}EXPORT_SYMBOL(inode_set_ctime_to_ts);
/** * timestamp_truncate - Truncate timespec to a granularity * @t: Timespec * @inode: inode being updated * * Truncate a timespec to the granularity supported by the fs * containing the inode. Always rounds down. gran must * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns). */struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode){ struct super_block *sb = inode->i_sb; unsigned int gran = sb->s_time_gran;
t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max); if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min)) t.tv_nsec = 0;
/* Avoid division in the common cases 1 ns and 1 s. */ if (gran == 1) ; /* nothing */ else if (gran == NSEC_PER_SEC) t.tv_nsec = 0; else if (gran > 1 && gran < NSEC_PER_SEC) t.tv_nsec -= t.tv_nsec % gran; else WARN(1, "invalid file time granularity: %u", gran); return t;}EXPORT_SYMBOL(timestamp_truncate);
/** * inode_set_ctime_current - set the ctime to current_time * @inode: inode * * Set the inode's ctime to the current value for the inode. Returns the * current value that was assigned. If this is not a multigrain inode, then we * set it to the later of the coarse time and floor value. * * If it is multigrain, then we first see if the coarse-grained timestamp is * distinct from what is already there. If so, then use that. Otherwise, get a * fine-grained timestamp. * * After that, try to swap the new value into i_ctime_nsec. Accept the * resulting ctime, regardless of the outcome of the swap. If it has * already been replaced, then that timestamp is later than the earlier * unacceptable one, and is thus acceptable. */struct timespec64 inode_set_ctime_current(struct inode *inode){ struct timespec64 now; u32 cns, cur;
ktime_get_coarse_real_ts64_mg(&now); now = timestamp_truncate(now, inode);
/* Just return that if this is not a multigrain fs */ if (!is_mgtime(inode)) { inode_set_ctime_to_ts(inode, now); goto out; }
/* * A fine-grained time is only needed if someone has queried * for timestamps, and the current coarse grained time isn't * later than what's already there. */ cns = smp_load_acquire(&inode->i_ctime_nsec); if (cns & I_CTIME_QUERIED) { struct timespec64 ctime = { .tv_sec = inode->i_ctime_sec, .tv_nsec = cns & ~I_CTIME_QUERIED };
if (timespec64_compare(&now, &ctime) <= 0) { ktime_get_real_ts64_mg(&now); now = timestamp_truncate(now, inode); mgtime_counter_inc(mg_fine_stamps); } } mgtime_counter_inc(mg_ctime_updates);
/* No need to cmpxchg if it's exactly the same */ if (cns == now.tv_nsec && inode->i_ctime_sec == now.tv_sec) { trace_ctime_xchg_skip(inode, &now); goto out; } cur = cns;retry: /* Try to swap the nsec value into place. */ if (try_cmpxchg(&inode->i_ctime_nsec, &cur, now.tv_nsec)) { /* If swap occurred, then we're (mostly) done */ inode->i_ctime_sec = now.tv_sec; trace_ctime_ns_xchg(inode, cns, now.tv_nsec, cur); mgtime_counter_inc(mg_ctime_swaps); } else { /* * Was the change due to someone marking the old ctime QUERIED? * If so then retry the swap. This can only happen once since * the only way to clear I_CTIME_QUERIED is to stamp the inode * with a new ctime. */ if (!(cns & I_CTIME_QUERIED) && (cns | I_CTIME_QUERIED) == cur) { cns = cur; goto retry; } /* Otherwise, keep the existing ctime */ now.tv_sec = inode->i_ctime_sec; now.tv_nsec = cur & ~I_CTIME_QUERIED; }out: return now;}EXPORT_SYMBOL(inode_set_ctime_current);
/** * inode_set_ctime_deleg - try to update the ctime on a delegated inode * @inode: inode to update * @update: timespec64 to set the ctime * * Attempt to atomically update the ctime on behalf of a delegation holder. * * The nfs server can call back the holder of a delegation to get updated * inode attributes, including the mtime. When updating the mtime, update * the ctime to a value at least equal to that. * * This can race with concurrent updates to the inode, in which * case the update is skipped. * * Note that this works even when multigrain timestamps are not enabled, * so it is used in either case. */struct timespec64 inode_set_ctime_deleg(struct inode *inode, struct timespec64 update){ struct timespec64 now, cur_ts; u32 cur, old;
/* pairs with try_cmpxchg below */ cur = smp_load_acquire(&inode->i_ctime_nsec); cur_ts.tv_nsec = cur & ~I_CTIME_QUERIED; cur_ts.tv_sec = inode->i_ctime_sec;
/* If the update is older than the existing value, skip it. */ if (timespec64_compare(&update, &cur_ts) <= 0) return cur_ts;
ktime_get_coarse_real_ts64_mg(&now);
/* Clamp the update to "now" if it's in the future */ if (timespec64_compare(&update, &now) > 0) update = now;
update = timestamp_truncate(update, inode);
/* No need to update if the values are already the same */ if (timespec64_equal(&update, &cur_ts)) return cur_ts;
/* * Try to swap the nsec value into place. If it fails, that means * it raced with an update due to a write or similar activity. That * stamp takes precedence, so just skip the update. */retry: old = cur; if (try_cmpxchg(&inode->i_ctime_nsec, &cur, update.tv_nsec)) { inode->i_ctime_sec = update.tv_sec; mgtime_counter_inc(mg_ctime_swaps); return update; }
/* * Was the change due to another task marking the old ctime QUERIED? * * If so, then retry the swap. This can only happen once since * the only way to clear I_CTIME_QUERIED is to stamp the inode * with a new ctime. */ if (!(old & I_CTIME_QUERIED) && (cur == (old | I_CTIME_QUERIED))) goto retry;
/* Otherwise, it was a new timestamp. */ cur_ts.tv_sec = inode->i_ctime_sec; cur_ts.tv_nsec = cur & ~I_CTIME_QUERIED; return cur_ts;}EXPORT_SYMBOL(inode_set_ctime_deleg);
/** * in_group_or_capable - check whether caller is CAP_FSETID privileged * @idmap: idmap of the mount @inode was found from * @inode: inode to check * @vfsgid: the new/current vfsgid of @inode * * Check whether @vfsgid is in the caller's group list or if the caller is * privileged with CAP_FSETID over @inode. This can be used to determine * whether the setgid bit can be kept or must be dropped. * * Return: true if the caller is sufficiently privileged, false if not. */bool in_group_or_capable(struct mnt_idmap *idmap, const struct inode *inode, vfsgid_t vfsgid){ if (vfsgid_in_group_p(vfsgid)) return true; if (capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID)) return true; return false;}EXPORT_SYMBOL(in_group_or_capable);
/** * mode_strip_sgid - handle the sgid bit for non-directories * @idmap: idmap of the mount the inode was created from * @dir: parent directory inode * @mode: mode of the file to be created in @dir * * If the @mode of the new file has both the S_ISGID and S_IXGRP bit * raised and @dir has the S_ISGID bit raised ensure that the caller is * either in the group of the parent directory or they have CAP_FSETID * in their user namespace and are privileged over the parent directory. * In all other cases, strip the S_ISGID bit from @mode. * * Return: the new mode to use for the file */umode_t mode_strip_sgid(struct mnt_idmap *idmap, const struct inode *dir, umode_t mode){ if ((mode & (S_ISGID | S_IXGRP)) != (S_ISGID | S_IXGRP)) return mode; if (S_ISDIR(mode) || !dir || !(dir->i_mode & S_ISGID)) return mode; if (in_group_or_capable(idmap, dir, i_gid_into_vfsgid(idmap, dir))) return mode; return mode & ~S_ISGID;}EXPORT_SYMBOL(mode_strip_sgid);
#ifdef CONFIG_DEBUG_VFS/** * dump_inode - dump an inode. * @inode: inode to dump * @reason: reason for dumping * * If inode is an invalid pointer, we don't want to crash accessing it, * so probe everything depending on it carefully with get_kernel_nofault(). */void dump_inode(struct inode *inode, const char *reason){ struct super_block *sb; struct file_system_type *s_type; const char *fs_name_ptr; char fs_name[32] = {}; umode_t mode; unsigned short opflags; unsigned int flags; unsigned int state; int count;
if (get_kernel_nofault(sb, &inode->i_sb) || get_kernel_nofault(mode, &inode->i_mode) || get_kernel_nofault(opflags, &inode->i_opflags) || get_kernel_nofault(flags, &inode->i_flags)) { pr_warn("%s: unreadable inode:%px\n", reason, inode); return; }
state = inode_state_read_once(inode); count = icount_read_once(inode);
if (!sb || get_kernel_nofault(s_type, &sb->s_type) || !s_type || get_kernel_nofault(fs_name_ptr, &s_type->name) || !fs_name_ptr || strncpy_from_kernel_nofault(fs_name, fs_name_ptr, sizeof(fs_name) - 1) < 0) strscpy(fs_name, "<unknown, sb unreadable>");
pr_warn("%s: inode:%px fs:%s mode:%ho opflags:%#x flags:%#x state:%#x count:%d\n", reason, inode, fs_name, mode, opflags, flags, state, count);}EXPORT_SYMBOL(dump_inode);#endif