/* * linux/fs/inode.c * * (C) 1997 Linus Torvalds */ #include <linux/fs.h> #include <linux/mm.h> #include <linux/dcache.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/writeback.h> #include <linux/module.h> #include <linux/backing-dev.h> #include <linux/wait.h> #include <linux/rwsem.h> #include <linux/hash.h> #include <linux/swap.h> #include <linux/security.h> #include <linux/pagemap.h> #include <linux/cdev.h> #include <linux/bootmem.h> #include <linux/fsnotify.h> #include <linux/mount.h> #include <linux/async.h> #include <linux/posix_acl.h> #include <linux/ima.h> /* * This is needed for the following functions: * - inode_has_buffers * - invalidate_bdev * * FIXME: remove all knowledge of the buffer layer from this file */ #include <linux/buffer_head.h> /* * New inode.c implementation. * * This implementation has the basic premise of trying * to be extremely low-overhead and SMP-safe, yet be * simple enough to be "obviously correct". * * Famous last words. */ /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */ /* #define INODE_PARANOIA 1 */ /* #define INODE_DEBUG 1 */ /* * Inode lookup is no longer as critical as it used to be: * most of the lookups are going to be through the dcache. */ #define I_HASHBITS i_hash_shift #define I_HASHMASK i_hash_mask static unsigned int i_hash_mask __read_mostly; static unsigned int i_hash_shift __read_mostly; /* * Each inode can be on two separate lists. One is * the hash list of the inode, used for lookups. The * other linked list is the "type" list: * "in_use" - valid inode, i_count > 0, i_nlink > 0 * "dirty" - as "in_use" but also dirty * "unused" - valid inode, i_count = 0 * * A "dirty" list is maintained for each super block, * allowing for low-overhead inode sync() operations. */ static LIST_HEAD(inode_lru); static struct hlist_head *inode_hashtable __read_mostly; /* * A simple spinlock to protect the list manipulations. * * NOTE! You also have to own the lock if you change * the i_state of an inode while it is in use.. */ DEFINE_SPINLOCK(inode_lock); /* * iprune_sem provides exclusion between the kswapd or try_to_free_pages * icache shrinking path, and the umount path. Without this exclusion, * by the time prune_icache calls iput for the inode whose pages it has * been invalidating, or by the time it calls clear_inode & destroy_inode * from its final dispose_list, the struct super_block they refer to * (for inode->i_sb->s_op) may already have been freed and reused. * * We make this an rwsem because the fastpath is icache shrinking. In * some cases a filesystem may be doing a significant amount of work in * its inode reclaim code, so this should improve parallelism. */ static DECLARE_RWSEM(iprune_sem); /* * Statistics gathering.. */ struct inodes_stat_t inodes_stat; static DEFINE_PER_CPU(unsigned int, nr_inodes); static struct kmem_cache *inode_cachep __read_mostly; static int get_nr_inodes(void) { int i; int sum = 0; for_each_possible_cpu(i) sum += per_cpu(nr_inodes, i); return sum < 0 ? 0 : sum; } static inline int get_nr_inodes_unused(void) { return inodes_stat.nr_unused; } int get_nr_dirty_inodes(void) { /* not actually dirty inodes, but a wild approximation */ int nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); return nr_dirty > 0 ? nr_dirty : 0; } /* * Handle nr_inode sysctl */ #ifdef CONFIG_SYSCTL int proc_nr_inodes(ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { inodes_stat.nr_inodes = get_nr_inodes(); return proc_dointvec(table, write, buffer, lenp, ppos); } #endif static void wake_up_inode(struct inode *inode) { /* * Prevent speculative execution through spin_unlock(&inode_lock); */ smp_mb(); wake_up_bit(&inode->i_state, __I_NEW); } /** * inode_init_always - perform inode structure intialisation * @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 address_space_operations empty_aops; static const struct inode_operations empty_iops; static const struct file_operations empty_fops; struct address_space *const mapping = &inode->i_data; inode->i_sb = sb; inode->i_blkbits = sb->s_blocksize_bits; inode->i_flags = 0; atomic_set(&inode->i_count, 1); inode->i_op = &empty_iops; inode->i_fop = &empty_fops; inode->i_nlink = 1; inode->i_uid = 0; inode->i_gid = 0; atomic_set(&inode->i_writecount, 0); inode->i_size = 0; inode->i_blocks = 0; inode->i_bytes = 0; inode->i_generation = 0; #ifdef CONFIG_QUOTA memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); #endif inode->i_pipe = NULL; inode->i_bdev = NULL; inode->i_cdev = NULL; inode->i_rdev = 0; inode->dirtied_when = 0; if (security_inode_alloc(inode)) goto out; spin_lock_init(&inode->i_lock); lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); mutex_init(&inode->i_mutex); lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); init_rwsem(&inode->i_alloc_sem); lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key); mapping->a_ops = &empty_aops; mapping->host = inode; mapping->flags = 0; mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); mapping->assoc_mapping = NULL; mapping->backing_dev_info = &default_backing_dev_info; mapping->writeback_index = 0; /* * If the block_device provides a backing_dev_info for client * inodes then use that. Otherwise the inode share the bdev's * backing_dev_info. */ if (sb->s_bdev) { struct backing_dev_info *bdi; bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; mapping->backing_dev_info = bdi; } inode->i_private = NULL; inode->i_mapping = mapping; #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 this_cpu_inc(nr_inodes); return 0; out: return -ENOMEM; } EXPORT_SYMBOL(inode_init_always); static struct inode *alloc_inode(struct super_block *sb) { struct inode *inode; if (sb->s_op->alloc_inode) inode = sb->s_op->alloc_inode(sb); else inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); if (!inode) return NULL; if (unlikely(inode_init_always(sb, inode))) { if (inode->i_sb->s_op->destroy_inode) inode->i_sb->s_op->destroy_inode(inode); else kmem_cache_free(inode_cachep, inode); return NULL; } return inode; } void free_inode_nonrcu(struct inode *inode) { kmem_cache_free(inode_cachep, inode); } EXPORT_SYMBOL(free_inode_nonrcu); void __destroy_inode(struct inode *inode) { BUG_ON(inode_has_buffers(inode)); security_inode_free(inode); fsnotify_inode_delete(inode); #ifdef CONFIG_FS_POSIX_ACL if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) posix_acl_release(inode->i_acl); if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) posix_acl_release(inode->i_default_acl); #endif this_cpu_dec(nr_inodes); } EXPORT_SYMBOL(__destroy_inode); static void i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); INIT_LIST_HEAD(&inode->i_dentry); kmem_cache_free(inode_cachep, inode); } static void destroy_inode(struct inode *inode) { BUG_ON(!list_empty(&inode->i_lru)); __destroy_inode(inode); if (inode->i_sb->s_op->destroy_inode) inode->i_sb->s_op->destroy_inode(inode); else call_rcu(&inode->i_rcu, i_callback); } /* * 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_dentry); INIT_LIST_HEAD(&inode->i_devices); INIT_LIST_HEAD(&inode->i_wb_list); INIT_LIST_HEAD(&inode->i_lru); INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC); spin_lock_init(&inode->i_data.tree_lock); spin_lock_init(&inode->i_data.i_mmap_lock); INIT_LIST_HEAD(&inode->i_data.private_list); spin_lock_init(&inode->i_data.private_lock); INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap); INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear); i_size_ordered_init(inode); #ifdef CONFIG_FSNOTIFY INIT_HLIST_HEAD(&inode->i_fsnotify_marks); #endif } EXPORT_SYMBOL(inode_init_once); static void init_once(void *foo) { struct inode *inode = (struct inode *) foo; inode_init_once(inode); } /* * inode_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_lru_list_add(struct inode *inode) { if (list_empty(&inode->i_lru)) { list_add(&inode->i_lru, &inode_lru); inodes_stat.nr_unused++; } } static void inode_lru_list_del(struct inode *inode) { if (!list_empty(&inode->i_lru)) { list_del_init(&inode->i_lru); inodes_stat.nr_unused--; } } static inline void __inode_sb_list_add(struct inode *inode) { list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); } /** * 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_lock); __inode_sb_list_add(inode); spin_unlock(&inode_lock); } EXPORT_SYMBOL_GPL(inode_sb_list_add); static inline void __inode_sb_list_del(struct inode *inode) { list_del_init(&inode->i_sb_list); } 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_HASHBITS); return tmp & I_HASHMASK; } /** * __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_lock); hlist_add_head(&inode->i_hash, b); spin_unlock(&inode_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. */ static void __remove_inode_hash(struct inode *inode) { hlist_del_init(&inode->i_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_lock); hlist_del_init(&inode->i_hash); spin_unlock(&inode_lock); } EXPORT_SYMBOL(remove_inode_hash); void end_writeback(struct inode *inode) { might_sleep(); BUG_ON(inode->i_data.nrpages); BUG_ON(!list_empty(&inode->i_data.private_list)); BUG_ON(!(inode->i_state & I_FREEING)); BUG_ON(inode->i_state & I_CLEAR); inode_sync_wait(inode); /* don't need i_lock here, no concurrent mods to i_state */ inode->i_state = I_FREEING | I_CLEAR; } EXPORT_SYMBOL(end_writeback); static void evict(struct inode *inode) { const struct super_operations *op = inode->i_sb->s_op; if (op->evict_inode) { op->evict_inode(inode); } else { if (inode->i_data.nrpages) truncate_inode_pages(&inode->i_data, 0); end_writeback(inode); } if (S_ISBLK(inode->i_mode) && inode->i_bdev) bd_forget(inode); if (S_ISCHR(inode->i_mode) && inode->i_cdev) cd_forget(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); spin_lock(&inode_lock); __remove_inode_hash(inode); __inode_sb_list_del(inode); spin_unlock(&inode_lock); wake_up_inode(inode); destroy_inode(inode); } } /** * 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 MS_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); down_write(&iprune_sem); spin_lock(&inode_lock); list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { if (atomic_read(&inode->i_count)) continue; if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { WARN_ON(1); continue; } inode->i_state |= I_FREEING; /* * Move the inode off the IO lists and LRU once I_FREEING is * set so that it won't get moved back on there if it is dirty. */ list_move(&inode->i_lru, &dispose); list_del_init(&inode->i_wb_list); if (!(inode->i_state & (I_DIRTY | I_SYNC))) inodes_stat.nr_unused--; } spin_unlock(&inode_lock); dispose_list(&dispose); up_write(&iprune_sem); } /** * invalidate_inodes - attempt to free all inodes on a superblock * @sb: superblock to operate on * * Attempts to free all inodes for a given superblock. If there were any * busy inodes return a non-zero value, else zero. */ int invalidate_inodes(struct super_block *sb) { int busy = 0; struct inode *inode, *next; LIST_HEAD(dispose); down_write(&iprune_sem); spin_lock(&inode_lock); list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) continue; if (atomic_read(&inode->i_count)) { busy = 1; continue; } inode->i_state |= I_FREEING; /* * Move the inode off the IO lists and LRU once I_FREEING is * set so that it won't get moved back on there if it is dirty. */ list_move(&inode->i_lru, &dispose); list_del_init(&inode->i_wb_list); if (!(inode->i_state & (I_DIRTY | I_SYNC))) inodes_stat.nr_unused--; } spin_unlock(&inode_lock); dispose_list(&dispose); up_write(&iprune_sem); return busy; } static int can_unuse(struct inode *inode) { if (inode->i_state & ~I_REFERENCED) return 0; if (inode_has_buffers(inode)) return 0; if (atomic_read(&inode->i_count)) return 0; if (inode->i_data.nrpages) return 0; return 1; } /* * Scan `goal' inodes on the unused list for freeable ones. They are moved to a * temporary list and then are freed outside inode_lock by dispose_list(). * * Any inodes which are pinned purely because of attached pagecache have their * pagecache removed. If the inode has metadata buffers attached to * mapping->private_list then try to remove them. * * 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 void prune_icache(int nr_to_scan) { LIST_HEAD(freeable); int nr_scanned; unsigned long reap = 0; down_read(&iprune_sem); spin_lock(&inode_lock); for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { struct inode *inode; if (list_empty(&inode_lru)) break; inode = list_entry(inode_lru.prev, struct inode, i_lru); /* * Referenced or dirty inodes are still in use. Give them * another pass through the LRU as we canot reclaim them now. */ if (atomic_read(&inode->i_count) || (inode->i_state & ~I_REFERENCED)) { list_del_init(&inode->i_lru); inodes_stat.nr_unused--; continue; } /* recently referenced inodes get one more pass */ if (inode->i_state & I_REFERENCED) { list_move(&inode->i_lru, &inode_lru); inode->i_state &= ~I_REFERENCED; continue; } if (inode_has_buffers(inode) || inode->i_data.nrpages) { __iget(inode); spin_unlock(&inode_lock); if (remove_inode_buffers(inode)) reap += invalidate_mapping_pages(&inode->i_data, 0, -1); iput(inode); spin_lock(&inode_lock); if (inode != list_entry(inode_lru.next, struct inode, i_lru)) continue; /* wrong inode or list_empty */ if (!can_unuse(inode)) continue; } WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; /* * Move the inode off the IO lists and LRU once I_FREEING is * set so that it won't get moved back on there if it is dirty. */ list_move(&inode->i_lru, &freeable); list_del_init(&inode->i_wb_list); inodes_stat.nr_unused--; } if (current_is_kswapd()) __count_vm_events(KSWAPD_INODESTEAL, reap); else __count_vm_events(PGINODESTEAL, reap); spin_unlock(&inode_lock); dispose_list(&freeable); up_read(&iprune_sem); } /* * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, * "unused" means that no dentries are referring to the inodes: the files are * not open and the dcache references to those inodes have already been * reclaimed. * * This function is passed the number of inodes to scan, and it returns the * total number of remaining possibly-reclaimable inodes. */ static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask) { if (nr) { /* * Nasty deadlock avoidance. We may hold various FS locks, * and we don't want to recurse into the FS that called us * in clear_inode() and friends.. */ if (!(gfp_mask & __GFP_FS)) return -1; prune_icache(nr); } return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure; } static struct shrinker icache_shrinker = { .shrink = shrink_icache_memory, .seeks = DEFAULT_SEEKS, }; 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 hlist_node *node; struct inode *inode = NULL; repeat: hlist_for_each_entry(inode, node, head, i_hash) { if (inode->i_sb != sb) continue; if (!test(inode, data)) continue; if (inode->i_state & (I_FREEING|I_WILL_FREE)) { __wait_on_freeing_inode(inode); goto repeat; } __iget(inode); 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 hlist_node *node; struct inode *inode = NULL; repeat: hlist_for_each_entry(inode, node, head, i_hash) { if (inode->i_ino != ino) continue; if (inode->i_sb != sb) continue; if (inode->i_state & (I_FREEING|I_WILL_FREE)) { __wait_on_freeing_inode(inode); goto repeat; } __iget(inode); 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 *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; spin_lock_prefetch(&inode_lock); inode = alloc_inode(sb); if (inode) { spin_lock(&inode_lock); __inode_sb_list_add(inode); inode->i_state = 0; spin_unlock(&inode_lock); } return inode; } EXPORT_SYMBOL(new_inode); void unlock_new_inode(struct inode *inode) { #ifdef CONFIG_DEBUG_LOCK_ALLOC 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_mutex, &type->i_mutex_key)) { /* * ensure nobody is actually holding i_mutex */ mutex_destroy(&inode->i_mutex); mutex_init(&inode->i_mutex); lockdep_set_class(&inode->i_mutex, &type->i_mutex_dir_key); } } #endif /* * This is special! We do not need the spinlock when clearing I_NEW, * because we're guaranteed that nobody else tries to do anything about * the state of the inode when it is locked, as we just created it (so * there can be no old holders that haven't tested I_NEW). * However we must emit the memory barrier so that other CPUs reliably * see the clearing of I_NEW after the other inode initialisation has * completed. */ smp_mb(); WARN_ON(!(inode->i_state & I_NEW)); inode->i_state &= ~I_NEW; wake_up_inode(inode); } EXPORT_SYMBOL(unlock_new_inode); /* * This is called without the inode lock held.. Be careful. * * We no longer cache the sb_flags in i_flags - see fs.h * -- rmk@arm.uk.linux.org */ static struct inode *get_new_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data) { struct inode *inode; inode = alloc_inode(sb); if (inode) { struct inode *old; spin_lock(&inode_lock); /* We released the lock, so.. */ old = find_inode(sb, head, test, data); if (!old) { if (set(inode, data)) goto set_failed; hlist_add_head(&inode->i_hash, head); __inode_sb_list_add(inode); inode->i_state = I_NEW; spin_unlock(&inode_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_lock); destroy_inode(inode); inode = old; wait_on_inode(inode); } return inode; set_failed: spin_unlock(&inode_lock); destroy_inode(inode); return NULL; } /* * get_new_inode_fast is the fast path version of get_new_inode, see the * comment at iget_locked for details. */ static struct inode *get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino) { struct inode *inode; inode = alloc_inode(sb); if (inode) { struct inode *old; spin_lock(&inode_lock); /* We released the lock, so.. */ old = find_inode_fast(sb, head, ino); if (!old) { inode->i_ino = ino; hlist_add_head(&inode->i_hash, head); __inode_sb_list_add(inode); inode->i_state = I_NEW; spin_unlock(&inode_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_lock); destroy_inode(inode); inode = old; wait_on_inode(inode); } return inode; } /* * 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 hlist_node *node; struct inode *inode; hlist_for_each_entry(inode, node, 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; spin_lock(&inode_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); spin_unlock(&inode_lock); return res; } EXPORT_SYMBOL(iunique); struct inode *igrab(struct inode *inode) { spin_lock(&inode_lock); if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) __iget(inode); else /* * 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; spin_unlock(&inode_lock); return inode; } EXPORT_SYMBOL(igrab); /** * ifind - internal function, you want ilookup5() or iget5(). * @sb: super block of file system to search * @head: the head of the list to search * @test: callback used for comparisons between inodes * @data: opaque data pointer to pass to @test * @wait: if true wait for the inode to be unlocked, if false do not * * ifind() searches for the inode specified by @data in the inode * cache. This is a generalized version of ifind_fast() for file systems where * the inode number is not sufficient for unique identification of an inode. * * If the inode is in the cache, the inode is returned with an incremented * reference count. * * Otherwise NULL is returned. * * Note, @test is called with the inode_lock held, so can't sleep. */ static struct inode *ifind(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data, const int wait) { struct inode *inode; spin_lock(&inode_lock); inode = find_inode(sb, head, test, data); if (inode) { spin_unlock(&inode_lock); if (likely(wait)) wait_on_inode(inode); return inode; } spin_unlock(&inode_lock); return NULL; } /** * ifind_fast - internal function, you want ilookup() or iget(). * @sb: super block of file system to search * @head: head of the list to search * @ino: inode number to search for * * ifind_fast() searches for the inode @ino in the inode cache. This is for * file systems where the inode number is sufficient for unique identification * of an inode. * * If the inode is in the cache, the inode is returned with an incremented * reference count. * * Otherwise NULL is returned. */ static struct inode *ifind_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino) { struct inode *inode; spin_lock(&inode_lock); inode = find_inode_fast(sb, head, ino); if (inode) { spin_unlock(&inode_lock); wait_on_inode(inode); return inode; } spin_unlock(&inode_lock); return NULL; } /** * 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 * * ilookup5() uses ifind() to search for the inode specified by @hashval and * @data in the inode cache. This is a generalized version of ilookup() for * file systems where the inode number is not sufficient for unique * identification of an inode. * * If the inode is in the cache, the inode is returned with an incremented * reference count. Note, the inode lock 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. * * Otherwise NULL is returned. * * Note, @test is called with the inode_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); return ifind(sb, head, test, data, 0); } 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 * * ilookup5() uses ifind() to search for the inode specified by @hashval and * @data in the inode cache. This is a generalized version of ilookup() for * file systems where the inode number is not sufficient for unique * identification of an inode. * * If the inode is in the cache, the inode lock is waited upon and the inode is * returned with an incremented reference count. * * Otherwise NULL is returned. * * Note, @test is called with the inode_lock held, so can't sleep. */ struct inode *ilookup5(struct super_block *sb, unsigned long hashval, int (*test)(struct inode *, void *), void *data) { struct hlist_head *head = inode_hashtable + hash(sb, hashval); return ifind(sb, head, test, data, 1); } 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 * * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. * This is for file systems where the inode number is sufficient for unique * identification of an inode. * * If the inode is in the cache, the inode is returned with an incremented * reference count. * * Otherwise NULL is returned. */ struct inode *ilookup(struct super_block *sb, unsigned long ino) { struct hlist_head *head = inode_hashtable + hash(sb, ino); return ifind_fast(sb, head, ino); } EXPORT_SYMBOL(ilookup); /** * 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 * * iget5_locked() uses ifind() to search for the inode specified by @hashval * and @data in the inode cache and if present it is returned 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, get_new_inode() is called to allocate a new * inode and this is returned 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_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 hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode; inode = ifind(sb, head, test, data, 1); if (inode) return inode; /* * get_new_inode() will do the right thing, re-trying the search * in case it had to block at any point. */ return get_new_inode(sb, head, test, set, data); } 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 * * iget_locked() uses ifind_fast() to search for the inode specified by @ino in * the inode cache and if present it is returned 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, get_new_inode_fast() is called to allocate a * new inode and this is returned 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; inode = ifind_fast(sb, head, ino); if (inode) return inode; /* * get_new_inode_fast() will do the right thing, re-trying the search * in case it had to block at any point. */ return get_new_inode_fast(sb, head, ino); } EXPORT_SYMBOL(iget_locked); 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); inode->i_state |= I_NEW; while (1) { struct hlist_node *node; struct inode *old = NULL; spin_lock(&inode_lock); hlist_for_each_entry(old, node, head, i_hash) { if (old->i_ino != ino) continue; if (old->i_sb != sb) continue; if (old->i_state & (I_FREEING|I_WILL_FREE)) continue; break; } if (likely(!node)) { hlist_add_head(&inode->i_hash, head); spin_unlock(&inode_lock); return 0; } __iget(old); spin_unlock(&inode_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 super_block *sb = inode->i_sb; struct hlist_head *head = inode_hashtable + hash(sb, hashval); inode->i_state |= I_NEW; while (1) { struct hlist_node *node; struct inode *old = NULL; spin_lock(&inode_lock); hlist_for_each_entry(old, node, head, i_hash) { if (old->i_sb != sb) continue; if (!test(old, data)) continue; if (old->i_state & (I_FREEING|I_WILL_FREE)) continue; break; } if (likely(!node)) { hlist_add_head(&inode->i_hash, head); spin_unlock(&inode_lock); return 0; } __iget(old); spin_unlock(&inode_lock); wait_on_inode(old); if (unlikely(!inode_unhashed(old))) { iput(old); return -EBUSY; } iput(old); } } EXPORT_SYMBOL(insert_inode_locked4); int generic_delete_inode(struct inode *inode) { return 1; } EXPORT_SYMBOL(generic_delete_inode); /* * Normal UNIX filesystem behaviour: delete the * inode when the usage count drops to zero, and * i_nlink is zero. */ int generic_drop_inode(struct inode *inode) { return !inode->i_nlink || inode_unhashed(inode); } EXPORT_SYMBOL_GPL(generic_drop_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; int drop; if (op && op->drop_inode) drop = op->drop_inode(inode); else drop = generic_drop_inode(inode); if (!drop) { if (sb->s_flags & MS_ACTIVE) { inode->i_state |= I_REFERENCED; if (!(inode->i_state & (I_DIRTY|I_SYNC))) { inode_lru_list_add(inode); } spin_unlock(&inode_lock); return; } WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_WILL_FREE; spin_unlock(&inode_lock); write_inode_now(inode, 1); spin_lock(&inode_lock); WARN_ON(inode->i_state & I_NEW); inode->i_state &= ~I_WILL_FREE; __remove_inode_hash(inode); } WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; /* * Move the inode off the IO lists and LRU once I_FREEING is * set so that it won't get moved back on there if it is dirty. */ inode_lru_list_del(inode); list_del_init(&inode->i_wb_list); __inode_sb_list_del(inode); spin_unlock(&inode_lock); evict(inode); remove_inode_hash(inode); wake_up_inode(inode); BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); destroy_inode(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) { BUG_ON(inode->i_state & I_CLEAR); if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) iput_final(inode); } } EXPORT_SYMBOL(iput); /** * bmap - find a block number in a file * @inode: inode of file * @block: block to find * * Returns the block number on the device holding the inode that * is the disk block number for the block of the file requested. * That is, asked for block 4 of inode 1 the function will return the * disk block relative to the disk start that holds that block of the * file. */ sector_t bmap(struct inode *inode, sector_t block) { sector_t res = 0; if (inode->i_mapping->a_ops->bmap) res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); return res; } EXPORT_SYMBOL(bmap); /* * With relative atime, only update atime if the previous atime is * earlier than 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 timespec now) { if (!(mnt->mnt_flags & MNT_RELATIME)) return 1; /* * Is mtime younger than atime? If yes, update atime: */ if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) return 1; /* * Is ctime younger than atime? If yes, update atime: */ if (timespec_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; } /** * touch_atime - update the access time * @mnt: mount the inode is accessed on * @dentry: dentry accessed * * 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. */ void touch_atime(struct vfsmount *mnt, struct dentry *dentry) { struct inode *inode = dentry->d_inode; struct timespec now; if (inode->i_flags & S_NOATIME) return; if (IS_NOATIME(inode)) return; if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) return; if (mnt->mnt_flags & MNT_NOATIME) return; if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) return; now = current_fs_time(inode->i_sb); if (!relatime_need_update(mnt, inode, now)) return; if (timespec_equal(&inode->i_atime, &now)) return; if (mnt_want_write(mnt)) return; inode->i_atime = now; mark_inode_dirty_sync(inode); mnt_drop_write(mnt); } EXPORT_SYMBOL(touch_atime); /** * 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 update via this function with the * S_NOCMTIME inode flag, e.g. for network filesystem where these * timestamps are handled by the server. */ void file_update_time(struct file *file) { struct inode *inode = file->f_path.dentry->d_inode; struct timespec now; enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0; /* First try to exhaust all avenues to not sync */ if (IS_NOCMTIME(inode)) return; now = current_fs_time(inode->i_sb); if (!timespec_equal(&inode->i_mtime, &now)) sync_it = S_MTIME; if (!timespec_equal(&inode->i_ctime, &now)) sync_it |= S_CTIME; if (IS_I_VERSION(inode)) sync_it |= S_VERSION; if (!sync_it) return; /* Finally allowed to write? Takes lock. */ if (mnt_want_write_file(file)) return; /* Only change inode inside the lock region */ if (sync_it & S_VERSION) inode_inc_iversion(inode); if (sync_it & S_CTIME) inode->i_ctime = now; if (sync_it & S_MTIME) inode->i_mtime = now; mark_inode_dirty_sync(inode); mnt_drop_write(file->f_path.mnt); } EXPORT_SYMBOL(file_update_time); 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); int inode_wait(void *word) { schedule(); return 0; } EXPORT_SYMBOL(inode_wait); /* * 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_inode() after removing from the hash list will DTRT. * * This is called with inode_lock held. */ 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.wait, TASK_UNINTERRUPTIBLE); spin_unlock(&inode_lock); schedule(); finish_wait(wq, &wait.wait); spin_lock(&inode_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) { int loop; /* 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, &i_hash_shift, &i_hash_mask, 0); for (loop = 0; loop < (1 << i_hash_shift); loop++) INIT_HLIST_HEAD(&inode_hashtable[loop]); } void __init inode_init(void) { int loop; /* inode slab cache */ inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode), 0, (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| SLAB_MEM_SPREAD), init_once); register_shrinker(&icache_shrinker); /* 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, 0, &i_hash_shift, &i_hash_mask, 0); for (loop = 0; loop < (1 << i_hash_shift); loop++) INIT_HLIST_HEAD(&inode_hashtable[loop]); } 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)) { inode->i_fop = &def_blk_fops; inode->i_rdev = rdev; } else if (S_ISFIFO(mode)) inode->i_fop = &def_fifo_fops; else if (S_ISSOCK(mode)) inode->i_fop = &bad_sock_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); /** * Init uid,gid,mode for new inode according to posix standards * @inode: New inode * @dir: Directory inode * @mode: mode of the new inode */ void inode_init_owner(struct inode *inode, const struct inode *dir, mode_t mode) { inode->i_uid = current_fsuid(); if (dir && dir->i_mode & S_ISGID) { inode->i_gid = dir->i_gid; if (S_ISDIR(mode)) mode |= S_ISGID; } else inode->i_gid = current_fsgid(); inode->i_mode = mode; } EXPORT_SYMBOL(inode_init_owner);