| // 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/mount.h> |
| #include <linux/posix_acl.h> |
| #include <linux/prefetch.h> |
| #include <linux/buffer_head.h> /* for inode_has_buffers */ |
| #include <linux/ratelimit.h> |
| #include <linux/list_lru.h> |
| #include <linux/iversion.h> |
| #include <trace/events/writeback.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_sb->s_inode_list_lock |
| * inode->i_lock |
| * |
| * iunique_lock |
| * inode_hash_lock |
| */ |
| |
| static unsigned int i_hash_mask __read_mostly; |
| static unsigned int i_hash_shift __read_mostly; |
| static struct hlist_head *inode_hashtable __read_mostly; |
| 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 __read_mostly; |
| |
| 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; |
| } |
| |
| /* |
| * Handle nr_inode sysctl |
| */ |
| #ifdef CONFIG_SYSCTL |
| /* |
| * Statistics gathering.. |
| */ |
| static struct inodes_stat_t inodes_stat; |
| |
| static int proc_nr_inodes(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 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 - perform inode structure initialisation |
| * @sb: superblock inode belongs to |
| * @inode: inode to initialise |
| * |
| * These are initializations that need to be done on every inode |
| * allocation as the fields are not initialised by slab allocation. |
| */ |
| int inode_init_always(struct super_block *sb, struct inode *inode) |
| { |
| 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; |
| 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; |
| 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); |
| #ifdef CONFIG_READ_ONLY_THP_FOR_FS |
| atomic_set(&mapping->nr_thps, 0); |
| #endif |
| mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
| mapping->private_data = NULL; |
| 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"); |
| 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))) |
| return -ENOMEM; |
| this_cpu_inc(nr_inodes); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(inode_init_always); |
| |
| 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); |
| } |
| |
| static 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) |
| { |
| BUG_ON(inode_has_buffers(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->i_state & 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); |
| INIT_LIST_HEAD(&mapping->private_list); |
| spin_lock_init(&mapping->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); |
| } |
| |
| /* |
| * inode->i_lock must be held |
| */ |
| void __iget(struct inode *inode) |
| { |
| atomic_inc(&inode->i_count); |
| } |
| |
| /* |
| * get additional reference to inode; caller must already hold one. |
| */ |
| void ihold(struct inode *inode) |
| { |
| WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
| } |
| EXPORT_SYMBOL(ihold); |
| |
| static void __inode_add_lru(struct inode *inode, bool rotate) |
| { |
| if (inode->i_state & (I_DIRTY_ALL | I_SYNC | I_FREEING | I_WILL_FREE)) |
| return; |
| if (atomic_read(&inode->i_count)) |
| return; |
| if (!(inode->i_sb->s_flags & SB_ACTIVE)) |
| return; |
| if (!mapping_shrinkable(&inode->i_data)) |
| return; |
| |
| if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
| this_cpu_inc(nr_unused); |
| else if (rotate) |
| inode->i_state |= I_REFERENCED; |
| } |
| |
| /* |
| * Add inode to LRU if needed (inode is unused and clean). |
| * |
| * Needs inode->i_lock held. |
| */ |
| void inode_add_lru(struct inode *inode) |
| { |
| __inode_add_lru(inode, false); |
| } |
| |
| static void inode_lru_list_del(struct inode *inode) |
| { |
| if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
| this_cpu_dec(nr_unused); |
| } |
| |
| /** |
| * inode_sb_list_add - add inode to the superblock list of inodes |
| * @inode: inode to add |
| */ |
| void inode_sb_list_add(struct inode *inode) |
| { |
| spin_lock(&inode->i_sb->s_inode_list_lock); |
| list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
| spin_unlock(&inode->i_sb->s_inode_list_lock); |
| } |
| EXPORT_SYMBOL_GPL(inode_sb_list_add); |
| |
| static inline void inode_sb_list_del(struct inode *inode) |
| { |
| if (!list_empty(&inode->i_sb_list)) { |
| spin_lock(&inode->i_sb->s_inode_list_lock); |
| list_del_init(&inode->i_sb_list); |
| spin_unlock(&inode->i_sb->s_inode_list_lock); |
| } |
| } |
| |
| static unsigned long hash(struct super_block *sb, unsigned long 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: unsigned long 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, unsigned long 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; |
| unsigned long 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:%lx\n", a_ops, ino); |
| return; |
| } |
| |
| dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias); |
| if (get_kernel_nofault(dentry, dentry_ptr)) { |
| pr_warn("aops:%ps ino:%lx invalid dentry:%px\n", |
| a_ops, ino, dentry_ptr); |
| return; |
| } |
| |
| /* |
| * if dentry is corrupted, the %pd handler may still crash, |
| * but it's unlikely that we reach here with a corrupt mapping |
| */ |
| pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry); |
| } |
| |
| void clear_inode(struct 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(!list_empty(&inode->i_data.private_list)); |
| BUG_ON(!(inode->i_state & I_FREEING)); |
| BUG_ON(inode->i_state & I_CLEAR); |
| BUG_ON(!list_empty(&inode->i_wb_list)); |
| /* don't need i_lock here, no concurrent mods to i_state */ |
| inode->i_state = 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->i_state & I_FREEING)); |
| BUG_ON(!list_empty(&inode->i_lru)); |
| |
| if (!list_empty(&inode->i_io_list)) |
| inode_io_list_del(inode); |
| |
| inode_sb_list_del(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); |
| |
| 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); |
| |
| spin_lock(&inode->i_lock); |
| wake_up_bit(&inode->i_state, __I_NEW); |
| BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
| spin_unlock(&inode->i_lock); |
| |
| 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, *next; |
| LIST_HEAD(dispose); |
| |
| again: |
| spin_lock(&sb->s_inode_list_lock); |
| list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
| if (atomic_read(&inode->i_count)) |
| continue; |
| |
| spin_lock(&inode->i_lock); |
| if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
| spin_unlock(&inode->i_lock); |
| continue; |
| } |
| |
| inode->i_state |= 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); |
| |
| /** |
| * invalidate_inodes - attempt to free all inodes on a superblock |
| * @sb: superblock to operate on |
| * @kill_dirty: flag to guide handling of dirty inodes |
| * |
| * Attempts to free all inodes for a given superblock. If there were any |
| * busy inodes return a non-zero value, else zero. |
| * If @kill_dirty is set, discard dirty inodes too, otherwise treat |
| * them as busy. |
| */ |
| int invalidate_inodes(struct super_block *sb, bool kill_dirty) |
| { |
| int busy = 0; |
| struct inode *inode, *next; |
| LIST_HEAD(dispose); |
| |
| again: |
| spin_lock(&sb->s_inode_list_lock); |
| list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
| spin_lock(&inode->i_lock); |
| if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
| spin_unlock(&inode->i_lock); |
| continue; |
| } |
| if (inode->i_state & I_DIRTY_ALL && !kill_dirty) { |
| spin_unlock(&inode->i_lock); |
| busy = 1; |
| continue; |
| } |
| if (atomic_read(&inode->i_count)) { |
| spin_unlock(&inode->i_lock); |
| busy = 1; |
| continue; |
| } |
| |
| inode->i_state |= I_FREEING; |
| inode_lru_list_del(inode); |
| spin_unlock(&inode->i_lock); |
| list_add(&inode->i_lru, &dispose); |
| 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); |
| |
| return busy; |
| } |
| |
| /* |
| * 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, spinlock_t *lru_lock, 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 (atomic_read(&inode->i_count) || |
| (inode->i_state & ~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->i_state & I_REFERENCED) { |
| inode->i_state &= ~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 (inode_has_buffers(inode) || !mapping_empty(&inode->i_data)) { |
| __iget(inode); |
| spin_unlock(&inode->i_lock); |
| spin_unlock(lru_lock); |
| if (remove_inode_buffers(inode)) { |
| unsigned long reap; |
| 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); |
| } |
| iput(inode); |
| spin_lock(lru_lock); |
| return LRU_RETRY; |
| } |
| |
| WARN_ON(inode->i_state & I_NEW); |
| inode->i_state |= 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); |
| /* |
| * 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) |
| { |
| struct inode *inode = NULL; |
| |
| repeat: |
| hlist_for_each_entry(inode, head, i_hash) { |
| if (inode->i_sb != sb) |
| continue; |
| if (!test(inode, data)) |
| continue; |
| spin_lock(&inode->i_lock); |
| if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
| __wait_on_freeing_inode(inode); |
| goto repeat; |
| } |
| if (unlikely(inode->i_state & I_CREATING)) { |
| spin_unlock(&inode->i_lock); |
| return ERR_PTR(-ESTALE); |
| } |
| __iget(inode); |
| spin_unlock(&inode->i_lock); |
| return inode; |
| } |
| 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, unsigned long ino) |
| { |
| struct inode *inode = NULL; |
| |
| repeat: |
| hlist_for_each_entry(inode, head, i_hash) { |
| if (inode->i_ino != ino) |
| continue; |
| if (inode->i_sb != sb) |
| continue; |
| spin_lock(&inode->i_lock); |
| if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
| __wait_on_freeing_inode(inode); |
| goto repeat; |
| } |
| if (unlikely(inode->i_state & I_CREATING)) { |
| spin_unlock(&inode->i_lock); |
| return ERR_PTR(-ESTALE); |
| } |
| __iget(inode); |
| spin_unlock(&inode->i_lock); |
| return inode; |
| } |
| 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 1024 |
| static 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_pseudo - 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 *new_inode_pseudo(struct super_block *sb) |
| { |
| struct inode *inode = alloc_inode(sb); |
| |
| if (inode) { |
| spin_lock(&inode->i_lock); |
| inode->i_state = 0; |
| spin_unlock(&inode->i_lock); |
| } |
| return inode; |
| } |
| |
| /** |
| * 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; |
| |
| spin_lock_prefetch(&sb->s_inode_list_lock); |
| |
| inode = new_inode_pseudo(sb); |
| if (inode) |
| inode_sb_list_add(inode); |
| return inode; |
| } |
| EXPORT_SYMBOL(new_inode); |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| void 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_mutex |
| */ |
| // mutex_destroy(&inode->i_mutex); |
| 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->i_state & I_NEW)); |
| inode->i_state &= ~I_NEW & ~I_CREATING; |
| smp_mb(); |
| wake_up_bit(&inode->i_state, __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->i_state & I_NEW)); |
| inode->i_state &= ~I_NEW; |
| smp_mb(); |
| wake_up_bit(&inode->i_state, __I_NEW); |
| spin_unlock(&inode->i_lock); |
| iput(inode); |
| } |
| EXPORT_SYMBOL(discard_new_inode); |
| |
| /** |
| * lock_two_inodes - lock two inodes (may be regular files but also dirs) |
| * |
| * Lock any non-NULL argument. The caller must make sure that if he is passing |
| * in two directories, one is not ancestor of the other. Zero, one or two |
| * objects may be locked by this function. |
| * |
| * @inode1: first inode to lock |
| * @inode2: second inode to lock |
| * @subclass1: inode lock subclass for the first lock obtained |
| * @subclass2: inode lock subclass for the second lock obtained |
| */ |
| void lock_two_inodes(struct inode *inode1, struct inode *inode2, |
| unsigned subclass1, unsigned subclass2) |
| { |
| if (!inode1 || !inode2) { |
| /* |
| * Make sure @subclass1 will be used for the acquired lock. |
| * This is not strictly necessary (no current caller cares) but |
| * let's keep things consistent. |
| */ |
| if (!inode1) |
| swap(inode1, inode2); |
| goto lock; |
| } |
| |
| /* |
| * If one object is directory and the other is not, we must make sure |
| * to lock directory first as the other object may be its child. |
| */ |
| if (S_ISDIR(inode2->i_mode) == S_ISDIR(inode1->i_mode)) { |
| if (inode1 > inode2) |
| swap(inode1, inode2); |
| } else if (!S_ISDIR(inode1->i_mode)) |
| swap(inode1, inode2); |
| lock: |
| if (inode1) |
| inode_lock_nested(inode1, subclass1); |
| if (inode2 && inode2 != inode1) |
| inode_lock_nested(inode2, subclass2); |
| } |
| |
| /** |
| * 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)); |
| lock_two_inodes(inode1, inode2, I_MUTEX_NORMAL, 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 |
| * |
| * Search for the inode specified by @hashval and @data in the inode cache, |
| * and if present it is return it with an increased reference count. This is |
| * a variant of iget5_locked() for callers that don't want to fail on memory |
| * allocation of inode. |
| * |
| * If the inode is not in cache, insert the pre-allocated inode to cache 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 both @test and @set are called with the inode_hash_lock held, so can't |
| * sleep. |
| */ |
| struct inode *inode_insert5(struct inode *inode, unsigned long 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; |
| |
| again: |
| spin_lock(&inode_hash_lock); |
| old = find_inode(inode->i_sb, head, test, data); |
| 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; |
| wait_on_inode(old); |
| if (unlikely(inode_unhashed(old))) { |
| iput(old); |
| goto again; |
| } |
| return old; |
| } |
| |
| if (set && unlikely(set(inode, data))) { |
| inode = NULL; |
| goto unlock; |
| } |
| |
| /* |
| * Return the locked inode with I_NEW set, the |
| * caller is responsible for filling in the contents |
| */ |
| spin_lock(&inode->i_lock); |
| inode->i_state |= I_NEW; |
| hlist_add_head_rcu(&inode->i_hash, head); |
| spin_unlock(&inode->i_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); |
| unlock: |
| spin_unlock(&inode_hash_lock); |
| |
| 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 it is 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 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(). |
| * |
| * Note both @test and @set are called with the inode_hash_lock held, so can't |
| * sleep. |
| */ |
| struct inode *iget5_locked(struct super_block *sb, unsigned long 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) { |
| new->i_state = 0; |
| inode = inode_insert5(new, hashval, test, set, data); |
| if (unlikely(inode != new)) |
| destroy_inode(new); |
| } |
| } |
| return inode; |
| } |
| EXPORT_SYMBOL(iget5_locked); |
| |
| /** |
| * 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, unsigned long ino) |
| { |
| struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| struct inode *inode; |
| again: |
| spin_lock(&inode_hash_lock); |
| inode = find_inode_fast(sb, head, ino); |
| spin_unlock(&inode_hash_lock); |
| if (inode) { |
| if (IS_ERR(inode)) |
| return NULL; |
| wait_on_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); |
| if (!old) { |
| inode->i_ino = ino; |
| spin_lock(&inode->i_lock); |
| inode->i_state = I_NEW; |
| hlist_add_head_rcu(&inode->i_hash, head); |
| spin_unlock(&inode->i_lock); |
| inode_sb_list_add(inode); |
| spin_unlock(&inode_hash_lock); |
| |
| /* 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; |
| wait_on_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, unsigned long 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); |
| |
| struct inode *igrab(struct inode *inode) |
| { |
| spin_lock(&inode->i_lock); |
| if (!(inode->i_state & (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); |
| |
| /** |
| * 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 |
| * |
| * 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, unsigned long hashval, |
| int (*test)(struct inode *, void *), void *data) |
| { |
| struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
| struct inode *inode; |
| |
| spin_lock(&inode_hash_lock); |
| inode = find_inode(sb, head, test, data); |
| 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, unsigned long hashval, |
| int (*test)(struct inode *, void *), void *data) |
| { |
| struct inode *inode; |
| again: |
| inode = ilookup5_nowait(sb, hashval, test, data); |
| if (inode) { |
| wait_on_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, unsigned long ino) |
| { |
| struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| struct inode *inode; |
| again: |
| spin_lock(&inode_hash_lock); |
| inode = find_inode_fast(sb, head, ino); |
| spin_unlock(&inode_hash_lock); |
| |
| if (inode) { |
| if (IS_ERR(inode)) |
| return NULL; |
| wait_on_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, |
| unsigned long hashval, |
| int (*match)(struct inode *, unsigned long, |
| 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, unsigned long 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 && |
| !(READ_ONCE(inode->i_state) & (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, |
| unsigned long 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 && |
| !(READ_ONCE(inode->i_state) & (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; |
| ino_t ino = inode->i_ino; |
| struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| |
| while (1) { |
| struct inode *old = NULL; |
| spin_lock(&inode_hash_lock); |
| 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); |
| if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
| spin_unlock(&old->i_lock); |
| continue; |
| } |
| break; |
| } |
| if (likely(!old)) { |
| spin_lock(&inode->i_lock); |
| inode->i_state |= 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 (unlikely(old->i_state & I_CREATING)) { |
| spin_unlock(&old->i_lock); |
| spin_unlock(&inode_hash_lock); |
| return -EBUSY; |
| } |
| __iget(old); |
| spin_unlock(&old->i_lock); |
| spin_unlock(&inode_hash_lock); |
| wait_on_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, unsigned long hashval, |
| int (*test)(struct inode *, void *), void *data) |
| { |
| struct inode *old; |
| |
| inode->i_state |= 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 generic_delete_inode(struct inode *inode) |
| { |
| return 1; |
| } |
| EXPORT_SYMBOL(generic_delete_inode); |
| |
| /* |
| * 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; |
| unsigned long state; |
| int drop; |
| |
| WARN_ON(inode->i_state & I_NEW); |
| |
| if (op->drop_inode) |
| drop = op->drop_inode(inode); |
| else |
| drop = generic_drop_inode(inode); |
| |
| if (!drop && |
| !(inode->i_state & I_DONTCACHE) && |
| (sb->s_flags & SB_ACTIVE)) { |
| __inode_add_lru(inode, true); |
| spin_unlock(&inode->i_lock); |
| return; |
| } |
| |
| state = inode->i_state; |
| if (!drop) { |
| WRITE_ONCE(inode->i_state, state | I_WILL_FREE); |
| spin_unlock(&inode->i_lock); |
| |
| write_inode_now(inode, 1); |
| |
| spin_lock(&inode->i_lock); |
| state = inode->i_state; |
| WARN_ON(state & I_NEW); |
| state &= ~I_WILL_FREE; |
| } |
| |
| WRITE_ONCE(inode->i_state, state | I_FREEING); |
| if (!list_empty(&inode->i_lru)) |
| 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) |
| { |
| if (!inode) |
| return; |
| BUG_ON(inode->i_state & I_CLEAR); |
| retry: |
| if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) { |
| if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) { |
| atomic_inc(&inode->i_count); |
| spin_unlock(&inode->i_lock); |
| trace_writeback_lazytime_iput(inode); |
| mark_inode_dirty_sync(inode); |
| goto retry; |
| } |
| iput_final(inode); |
| } |
| } |
| EXPORT_SYMBOL(iput); |
| |
| #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 int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
| struct timespec64 now) |
| { |
| |
| if (!(mnt->mnt_flags & MNT_RELATIME)) |
| return 1; |
| /* |
| * Is mtime younger than or equal to atime? If yes, update atime: |
| */ |
| if (timespec64_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
| return 1; |
| /* |
| * Is ctime younger than or equal to atime? If yes, update atime: |
| */ |
| if (timespec64_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
| return 1; |
| |
| /* |
| * Is the previous atime value older than a day? If yes, |
| * update atime: |
| */ |
| if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
| return 1; |
| /* |
| * Good, we can skip the atime update: |
| */ |
| return 0; |
| } |
| |
| int generic_update_time(struct inode *inode, struct timespec64 *time, int flags) |
| { |
| int dirty_flags = 0; |
| |
| if (flags & (S_ATIME | S_CTIME | S_MTIME)) { |
| if (flags & S_ATIME) |
| inode->i_atime = *time; |
| if (flags & S_CTIME) |
| inode->i_ctime = *time; |
| if (flags & S_MTIME) |
| inode->i_mtime = *time; |
| |
| if (inode->i_sb->s_flags & SB_LAZYTIME) |
| dirty_flags |= I_DIRTY_TIME; |
| else |
| dirty_flags |= I_DIRTY_SYNC; |
| } |
| |
| if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) |
| dirty_flags |= I_DIRTY_SYNC; |
| |
| __mark_inode_dirty(inode, dirty_flags); |
| return 0; |
| } |
| EXPORT_SYMBOL(generic_update_time); |
| |
| /* |
| * This does the actual work of updating an inodes time or version. Must have |
| * had called mnt_want_write() before calling this. |
| */ |
| int inode_update_time(struct inode *inode, struct timespec64 *time, int flags) |
| { |
| if (inode->i_op->update_time) |
| return inode->i_op->update_time(inode, time, flags); |
| return generic_update_time(inode, time, flags); |
| } |
| EXPORT_SYMBOL(inode_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; |
| |
| 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; |
| |
| if (timespec64_equal(&inode->i_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); |
| struct timespec64 now; |
| |
| if (!atime_needs_update(path, inode)) |
| return; |
| |
| if (!sb_start_write_trylock(inode->i_sb)) |
| return; |
| |
| if (__mnt_want_write(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. |
| */ |
| now = current_time(inode); |
| inode_update_time(inode, &now, S_ATIME); |
| __mnt_drop_write(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(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(file, 0); |
| } |
| EXPORT_SYMBOL(file_remove_privs); |
| |
| static int inode_needs_update_time(struct inode *inode, struct timespec64 *now) |
| { |
| int sync_it = 0; |
| |
| /* First try to exhaust all avenues to not sync */ |
| if (IS_NOCMTIME(inode)) |
| return 0; |
| |
| if (!timespec64_equal(&inode->i_mtime, now)) |
| sync_it = S_MTIME; |
| |
| if (!timespec64_equal(&inode->i_ctime, now)) |
| sync_it |= S_CTIME; |
| |
| if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode)) |
| sync_it |= S_VERSION; |
| |
| return sync_it; |
| } |
| |
| static int __file_update_time(struct file *file, struct timespec64 *now, |
| int sync_mode) |
| { |
| int ret = 0; |
| struct inode *inode = file_inode(file); |
| |
| /* try to update time settings */ |
| if (!__mnt_want_write_file(file)) { |
| ret = inode_update_time(inode, now, sync_mode); |
| __mnt_drop_write_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) |
| { |
| int ret; |
| struct inode *inode = file_inode(file); |
| struct timespec64 now = current_time(inode); |
| |
| ret = inode_needs_update_time(inode, &now); |
| if (ret <= 0) |
| return ret; |
| |
| return __file_update_time(file, &now, ret); |
| } |
| 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; |
| struct inode *inode = file_inode(file); |
| struct timespec64 now = current_time(inode); |
| |
| /* |
| * 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(file, flags); |
| if (ret) |
| return ret; |
| |
| if (unlikely(file->f_mode & FMODE_NOCMTIME)) |
| return 0; |
| |
| ret = inode_needs_update_time(inode, &now); |
| if (ret <= 0) |
| return ret; |
| if (flags & IOCB_NOWAIT) |
| return -EAGAIN; |
| |
| return __file_update_time(file, &now, ret); |
| } |
| |
| /** |
| * 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) |
| { |
| wait_queue_head_t *wq; |
| DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
| wq = bit_waitqueue(&inode->i_state, __I_NEW); |
| prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE); |
| spin_unlock(&inode->i_lock); |
| spin_unlock(&inode_hash_lock); |
| schedule(); |
| finish_wait(wq, &wait.wq_entry); |
| spin_lock(&inode_hash_lock); |
| } |
| |
| static __initdata unsigned long ihash_entries; |
| static int __init set_ihash_entries(char *str) |
| { |
| if (!str) |
| return 0; |
| ihash_entries = simple_strtoul(str, &str, 0); |
| return 1; |
| } |
| __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_MEM_SPREAD|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; |
| if (S_ISCHR(mode)) { |
| inode->i_fop = &def_chr_fops; |
| inode->i_rdev = rdev; |
| } else if (S_ISBLK(mode)) { |
| if (IS_ENABLED(CONFIG_BLOCK)) |
| inode->i_fop = &def_blk_fops; |
| inode->i_rdev = rdev; |
| } else if (S_ISFIFO(mode)) |
| inode->i_fop = &pipefifo_fops; |
| else if (S_ISSOCK(mode)) |
| ; /* leave it no_open_fops */ |
| else |
| printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
| " inode %s:%lu\n", mode, inode->i_sb->s_id, |
| inode->i_ino); |
| } |
| 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 passs @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 |
| */ |
| static void __inode_dio_wait(struct inode *inode) |
| { |
| wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP); |
| DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP); |
| |
| do { |
| prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE); |
| if (atomic_read(&inode->i_dio_count)) |
| schedule(); |
| } while (atomic_read(&inode->i_dio_count)); |
| finish_wait(wq, &q.wq_entry); |
| } |
| |
| /** |
| * 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_mutex. |
| */ |
| void inode_dio_wait(struct inode *inode) |
| { |
| if (atomic_read(&inode->i_dio_count)) |
| __inode_dio_wait(inode); |
| } |
| EXPORT_SYMBOL(inode_dio_wait); |
| |
| /* |
| * inode_set_flags - atomically set some inode flags |
| * |
| * Note: the caller should be holding i_mutex, 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_mutex 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); |
| |
| /** |
| * 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); |
| |
| /** |
| * current_time - Return FS time |
| * @inode: inode. |
| * |
| * Return the current time truncated to the time granularity supported by |
| * the fs. |
| * |
| * Note that inode and inode->sb cannot be NULL. |
| * Otherwise, the function warns and returns time without truncation. |
| */ |
| struct timespec64 current_time(struct inode *inode) |
| { |
| struct timespec64 now; |
| |
| ktime_get_coarse_real_ts64(&now); |
| |
| if (unlikely(!inode->i_sb)) { |
| WARN(1, "current_time() called with uninitialized super_block in the inode"); |
| return now; |
| } |
| |
| return timestamp_truncate(now, inode); |
| } |
| EXPORT_SYMBOL(current_time); |
| |
| /** |
| * 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 wether @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; |
| } |
| |
| /** |
| * 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); |