| /* |
| * linux/fs/inode.c |
| * |
| * (C) 1997 Linus Torvalds |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/dcache.h> |
| #include <linux/init.h> |
| #include <linux/quotaops.h> |
| #include <linux/slab.h> |
| #include <linux/writeback.h> |
| #include <linux/module.h> |
| #include <linux/backing-dev.h> |
| #include <linux/wait.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/inotify.h> |
| #include <linux/mount.h> |
| |
| /* |
| * This is needed for the following functions: |
| * - inode_has_buffers |
| * - invalidate_inode_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; |
| static unsigned int i_hash_shift; |
| |
| /* |
| * 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. |
| */ |
| |
| LIST_HEAD(inode_in_use); |
| LIST_HEAD(inode_unused); |
| static struct hlist_head *inode_hashtable; |
| |
| /* |
| * 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. |
| */ |
| DECLARE_MUTEX(iprune_sem); |
| |
| /* |
| * Statistics gathering.. |
| */ |
| struct inodes_stat_t inodes_stat; |
| |
| static kmem_cache_t * inode_cachep; |
| |
| static struct inode *alloc_inode(struct super_block *sb) |
| { |
| static struct address_space_operations empty_aops; |
| static struct inode_operations empty_iops; |
| static struct file_operations empty_fops; |
| struct inode *inode; |
| |
| if (sb->s_op->alloc_inode) |
| inode = sb->s_op->alloc_inode(sb); |
| else |
| inode = (struct inode *) kmem_cache_alloc(inode_cachep, SLAB_KERNEL); |
| |
| if (inode) { |
| 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; |
| 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->i_security = NULL; |
| inode->dirtied_when = 0; |
| if (security_inode_alloc(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; |
| } |
| |
| mapping->a_ops = &empty_aops; |
| mapping->host = inode; |
| mapping->flags = 0; |
| mapping_set_gfp_mask(mapping, GFP_HIGHUSER); |
| mapping->assoc_mapping = NULL; |
| mapping->backing_dev_info = &default_backing_dev_info; |
| |
| /* |
| * 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_backing_dev_info; |
| if (!bdi) |
| bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
| mapping->backing_dev_info = bdi; |
| } |
| memset(&inode->u, 0, sizeof(inode->u)); |
| inode->i_mapping = mapping; |
| } |
| return inode; |
| } |
| |
| void destroy_inode(struct inode *inode) |
| { |
| if (inode_has_buffers(inode)) |
| BUG(); |
| security_inode_free(inode); |
| if (inode->i_sb->s_op->destroy_inode) |
| inode->i_sb->s_op->destroy_inode(inode); |
| else |
| kmem_cache_free(inode_cachep, (inode)); |
| } |
| |
| |
| /* |
| * 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); |
| mutex_init(&inode->i_mutex); |
| init_rwsem(&inode->i_alloc_sem); |
| INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC); |
| rwlock_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); |
| spin_lock_init(&inode->i_lock); |
| i_size_ordered_init(inode); |
| #ifdef CONFIG_INOTIFY |
| INIT_LIST_HEAD(&inode->inotify_watches); |
| mutex_init(&inode->inotify_mutex); |
| #endif |
| } |
| |
| EXPORT_SYMBOL(inode_init_once); |
| |
| static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) |
| { |
| struct inode * inode = (struct inode *) foo; |
| |
| if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == |
| SLAB_CTOR_CONSTRUCTOR) |
| inode_init_once(inode); |
| } |
| |
| /* |
| * inode_lock must be held |
| */ |
| void __iget(struct inode * inode) |
| { |
| if (atomic_read(&inode->i_count)) { |
| atomic_inc(&inode->i_count); |
| return; |
| } |
| atomic_inc(&inode->i_count); |
| if (!(inode->i_state & (I_DIRTY|I_LOCK))) |
| list_move(&inode->i_list, &inode_in_use); |
| inodes_stat.nr_unused--; |
| } |
| |
| /** |
| * clear_inode - clear an inode |
| * @inode: inode to clear |
| * |
| * This is called by the filesystem to tell us |
| * that the inode is no longer useful. We just |
| * terminate it with extreme prejudice. |
| */ |
| void clear_inode(struct inode *inode) |
| { |
| might_sleep(); |
| invalidate_inode_buffers(inode); |
| |
| if (inode->i_data.nrpages) |
| BUG(); |
| if (!(inode->i_state & I_FREEING)) |
| BUG(); |
| if (inode->i_state & I_CLEAR) |
| BUG(); |
| wait_on_inode(inode); |
| DQUOT_DROP(inode); |
| if (inode->i_sb && inode->i_sb->s_op->clear_inode) |
| inode->i_sb->s_op->clear_inode(inode); |
| if (inode->i_bdev) |
| bd_forget(inode); |
| if (inode->i_cdev) |
| cd_forget(inode); |
| inode->i_state = I_CLEAR; |
| } |
| |
| EXPORT_SYMBOL(clear_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) |
| { |
| int nr_disposed = 0; |
| |
| while (!list_empty(head)) { |
| struct inode *inode; |
| |
| inode = list_entry(head->next, struct inode, i_list); |
| list_del(&inode->i_list); |
| |
| if (inode->i_data.nrpages) |
| truncate_inode_pages(&inode->i_data, 0); |
| clear_inode(inode); |
| |
| spin_lock(&inode_lock); |
| hlist_del_init(&inode->i_hash); |
| list_del_init(&inode->i_sb_list); |
| spin_unlock(&inode_lock); |
| |
| wake_up_inode(inode); |
| destroy_inode(inode); |
| nr_disposed++; |
| } |
| spin_lock(&inode_lock); |
| inodes_stat.nr_inodes -= nr_disposed; |
| spin_unlock(&inode_lock); |
| } |
| |
| /* |
| * Invalidate all inodes for a device. |
| */ |
| static int invalidate_list(struct list_head *head, struct list_head *dispose) |
| { |
| struct list_head *next; |
| int busy = 0, count = 0; |
| |
| next = head->next; |
| for (;;) { |
| struct list_head * tmp = next; |
| struct inode * inode; |
| |
| /* |
| * We can reschedule here without worrying about the list's |
| * consistency because the per-sb list of inodes must not |
| * change during umount anymore, and because iprune_sem keeps |
| * shrink_icache_memory() away. |
| */ |
| cond_resched_lock(&inode_lock); |
| |
| next = next->next; |
| if (tmp == head) |
| break; |
| inode = list_entry(tmp, struct inode, i_sb_list); |
| invalidate_inode_buffers(inode); |
| if (!atomic_read(&inode->i_count)) { |
| list_move(&inode->i_list, dispose); |
| inode->i_state |= I_FREEING; |
| count++; |
| continue; |
| } |
| busy = 1; |
| } |
| /* only unused inodes may be cached with i_count zero */ |
| inodes_stat.nr_unused -= count; |
| return busy; |
| } |
| |
| /** |
| * invalidate_inodes - discard the inodes on a device |
| * @sb: superblock |
| * |
| * Discard all of the inodes for a given superblock. If the discard |
| * fails because there are busy inodes then a non zero value is returned. |
| * If the discard is successful all the inodes have been discarded. |
| */ |
| int invalidate_inodes(struct super_block * sb) |
| { |
| int busy; |
| LIST_HEAD(throw_away); |
| |
| down(&iprune_sem); |
| spin_lock(&inode_lock); |
| inotify_unmount_inodes(&sb->s_inodes); |
| busy = invalidate_list(&sb->s_inodes, &throw_away); |
| spin_unlock(&inode_lock); |
| |
| dispose_list(&throw_away); |
| up(&iprune_sem); |
| |
| return busy; |
| } |
| |
| EXPORT_SYMBOL(invalidate_inodes); |
| |
| int __invalidate_device(struct block_device *bdev) |
| { |
| struct super_block *sb = get_super(bdev); |
| int res = 0; |
| |
| if (sb) { |
| /* |
| * no need to lock the super, get_super holds the |
| * read semaphore so the filesystem cannot go away |
| * under us (->put_super runs with the write lock |
| * hold). |
| */ |
| shrink_dcache_sb(sb); |
| res = invalidate_inodes(sb); |
| drop_super(sb); |
| } |
| invalidate_bdev(bdev, 0); |
| return res; |
| } |
| EXPORT_SYMBOL(__invalidate_device); |
| |
| static int can_unuse(struct inode *inode) |
| { |
| if (inode->i_state) |
| 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. We expect the final iput() on that inode to add it to |
| * the front of the inode_unused list. So look for it there and if the |
| * inode is still freeable, proceed. The right inode is found 99.9% of the |
| * time in testing on a 4-way. |
| * |
| * If the inode has metadata buffers attached to mapping->private_list then |
| * try to remove them. |
| */ |
| static void prune_icache(int nr_to_scan) |
| { |
| LIST_HEAD(freeable); |
| int nr_pruned = 0; |
| int nr_scanned; |
| unsigned long reap = 0; |
| |
| down(&iprune_sem); |
| spin_lock(&inode_lock); |
| for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { |
| struct inode *inode; |
| |
| if (list_empty(&inode_unused)) |
| break; |
| |
| inode = list_entry(inode_unused.prev, struct inode, i_list); |
| |
| if (inode->i_state || atomic_read(&inode->i_count)) { |
| list_move(&inode->i_list, &inode_unused); |
| continue; |
| } |
| if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
| __iget(inode); |
| spin_unlock(&inode_lock); |
| if (remove_inode_buffers(inode)) |
| reap += invalidate_inode_pages(&inode->i_data); |
| iput(inode); |
| spin_lock(&inode_lock); |
| |
| if (inode != list_entry(inode_unused.next, |
| struct inode, i_list)) |
| continue; /* wrong inode or list_empty */ |
| if (!can_unuse(inode)) |
| continue; |
| } |
| list_move(&inode->i_list, &freeable); |
| inode->i_state |= I_FREEING; |
| nr_pruned++; |
| } |
| inodes_stat.nr_unused -= nr_pruned; |
| spin_unlock(&inode_lock); |
| |
| dispose_list(&freeable); |
| up(&iprune_sem); |
| |
| if (current_is_kswapd()) |
| mod_page_state(kswapd_inodesteal, reap); |
| else |
| mod_page_state(pginodesteal, reap); |
| } |
| |
| /* |
| * 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(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 (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; |
| } |
| |
| static void __wait_on_freeing_inode(struct inode *inode); |
| /* |
| * Called with the inode lock held. |
| * NOTE: we are not increasing the inode-refcount, you must call __iget() |
| * by hand after calling find_inode now! This simplifies iunique and won't |
| * add any additional branch in the common code. |
| */ |
| 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 (node, head) { |
| inode = hlist_entry(node, struct inode, i_hash); |
| if (inode->i_sb != sb) |
| continue; |
| if (!test(inode, data)) |
| continue; |
| if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
| __wait_on_freeing_inode(inode); |
| goto repeat; |
| } |
| break; |
| } |
| return node ? inode : 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 (node, head) { |
| inode = hlist_entry(node, struct inode, i_hash); |
| if (inode->i_ino != ino) |
| continue; |
| if (inode->i_sb != sb) |
| continue; |
| if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
| __wait_on_freeing_inode(inode); |
| goto repeat; |
| } |
| break; |
| } |
| return node ? inode : NULL; |
| } |
| |
| /** |
| * new_inode - obtain an inode |
| * @sb: superblock |
| * |
| * Allocates a new inode for given superblock. |
| */ |
| struct inode *new_inode(struct super_block *sb) |
| { |
| static unsigned long last_ino; |
| struct inode * inode; |
| |
| spin_lock_prefetch(&inode_lock); |
| |
| inode = alloc_inode(sb); |
| if (inode) { |
| spin_lock(&inode_lock); |
| inodes_stat.nr_inodes++; |
| list_add(&inode->i_list, &inode_in_use); |
| list_add(&inode->i_sb_list, &sb->s_inodes); |
| inode->i_ino = ++last_ino; |
| inode->i_state = 0; |
| spin_unlock(&inode_lock); |
| } |
| return inode; |
| } |
| |
| EXPORT_SYMBOL(new_inode); |
| |
| void unlock_new_inode(struct inode *inode) |
| { |
| /* |
| * This is special! We do not need the spinlock |
| * when clearing I_LOCK, 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_LOCK). |
| */ |
| inode->i_state &= ~(I_LOCK|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; |
| |
| inodes_stat.nr_inodes++; |
| list_add(&inode->i_list, &inode_in_use); |
| list_add(&inode->i_sb_list, &sb->s_inodes); |
| hlist_add_head(&inode->i_hash, head); |
| inode->i_state = I_LOCK|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. |
| */ |
| __iget(old); |
| 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; |
| inodes_stat.nr_inodes++; |
| list_add(&inode->i_list, &inode_in_use); |
| list_add(&inode->i_sb_list, &sb->s_inodes); |
| hlist_add_head(&inode->i_hash, head); |
| inode->i_state = I_LOCK|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. |
| */ |
| __iget(old); |
| spin_unlock(&inode_lock); |
| destroy_inode(inode); |
| inode = old; |
| wait_on_inode(inode); |
| } |
| return inode; |
| } |
| |
| static inline 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; |
| } |
| |
| /** |
| * 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) |
| { |
| static ino_t counter; |
| struct inode *inode; |
| struct hlist_head * head; |
| ino_t res; |
| spin_lock(&inode_lock); |
| retry: |
| if (counter > max_reserved) { |
| head = inode_hashtable + hash(sb,counter); |
| res = counter++; |
| inode = find_inode_fast(sb, head, res); |
| if (!inode) { |
| spin_unlock(&inode_lock); |
| return res; |
| } |
| } else { |
| counter = max_reserved + 1; |
| } |
| goto retry; |
| |
| } |
| |
| 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) { |
| __iget(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) { |
| __iget(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 |
| * |
| * This is iget() without the read_inode() portion of get_new_inode(). |
| * |
| * 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 |
| * |
| * This is iget() without the read_inode() portion of get_new_inode_fast(). |
| * |
| * 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); |
| |
| /** |
| * __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 *head = inode_hashtable + hash(inode->i_sb, hashval); |
| spin_lock(&inode_lock); |
| hlist_add_head(&inode->i_hash, head); |
| 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. |
| */ |
| 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); |
| |
| /* |
| * Tell the filesystem that this inode is no longer of any interest and should |
| * be completely destroyed. |
| * |
| * We leave the inode in the inode hash table until *after* the filesystem's |
| * ->delete_inode completes. This ensures that an iget (such as nfsd might |
| * instigate) will always find up-to-date information either in the hash or on |
| * disk. |
| * |
| * I_FREEING is set so that no-one will take a new reference to the inode while |
| * it is being deleted. |
| */ |
| void generic_delete_inode(struct inode *inode) |
| { |
| struct super_operations *op = inode->i_sb->s_op; |
| |
| list_del_init(&inode->i_list); |
| list_del_init(&inode->i_sb_list); |
| inode->i_state|=I_FREEING; |
| inodes_stat.nr_inodes--; |
| spin_unlock(&inode_lock); |
| |
| security_inode_delete(inode); |
| |
| if (op->delete_inode) { |
| void (*delete)(struct inode *) = op->delete_inode; |
| if (!is_bad_inode(inode)) |
| DQUOT_INIT(inode); |
| /* Filesystems implementing their own |
| * s_op->delete_inode are required to call |
| * truncate_inode_pages and clear_inode() |
| * internally */ |
| delete(inode); |
| } else { |
| truncate_inode_pages(&inode->i_data, 0); |
| clear_inode(inode); |
| } |
| spin_lock(&inode_lock); |
| hlist_del_init(&inode->i_hash); |
| spin_unlock(&inode_lock); |
| wake_up_inode(inode); |
| if (inode->i_state != I_CLEAR) |
| BUG(); |
| destroy_inode(inode); |
| } |
| |
| EXPORT_SYMBOL(generic_delete_inode); |
| |
| static void generic_forget_inode(struct inode *inode) |
| { |
| struct super_block *sb = inode->i_sb; |
| |
| if (!hlist_unhashed(&inode->i_hash)) { |
| if (!(inode->i_state & (I_DIRTY|I_LOCK))) |
| list_move(&inode->i_list, &inode_unused); |
| inodes_stat.nr_unused++; |
| if (!sb || (sb->s_flags & MS_ACTIVE)) { |
| spin_unlock(&inode_lock); |
| return; |
| } |
| inode->i_state |= I_WILL_FREE; |
| spin_unlock(&inode_lock); |
| write_inode_now(inode, 1); |
| spin_lock(&inode_lock); |
| inode->i_state &= ~I_WILL_FREE; |
| inodes_stat.nr_unused--; |
| hlist_del_init(&inode->i_hash); |
| } |
| list_del_init(&inode->i_list); |
| list_del_init(&inode->i_sb_list); |
| inode->i_state |= I_FREEING; |
| inodes_stat.nr_inodes--; |
| spin_unlock(&inode_lock); |
| if (inode->i_data.nrpages) |
| truncate_inode_pages(&inode->i_data, 0); |
| clear_inode(inode); |
| wake_up_inode(inode); |
| destroy_inode(inode); |
| } |
| |
| /* |
| * Normal UNIX filesystem behaviour: delete the |
| * inode when the usage count drops to zero, and |
| * i_nlink is zero. |
| */ |
| void generic_drop_inode(struct inode *inode) |
| { |
| if (!inode->i_nlink) |
| generic_delete_inode(inode); |
| else |
| generic_forget_inode(inode); |
| } |
| |
| EXPORT_SYMBOL_GPL(generic_drop_inode); |
| |
| /* |
| * Called when we're dropping the last reference |
| * to an inode. |
| * |
| * Call the FS "drop()" function, defaulting to |
| * the legacy UNIX filesystem behaviour.. |
| * |
| * NOTE! NOTE! NOTE! We're called with the inode lock |
| * held, and the drop function is supposed to release |
| * the lock! |
| */ |
| static inline void iput_final(struct inode *inode) |
| { |
| struct super_operations *op = inode->i_sb->s_op; |
| void (*drop)(struct inode *) = generic_drop_inode; |
| |
| if (op && op->drop_inode) |
| drop = op->drop_inode; |
| drop(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) { |
| struct super_operations *op = inode->i_sb->s_op; |
| |
| BUG_ON(inode->i_state == I_CLEAR); |
| |
| if (op && op->put_inode) |
| op->put_inode(inode); |
| |
| 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); |
| |
| /** |
| * 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 (IS_RDONLY(inode)) |
| return; |
| |
| if ((inode->i_flags & S_NOATIME) || |
| (inode->i_sb->s_flags & MS_NOATIME) || |
| ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))) |
| return; |
| |
| /* |
| * We may have a NULL vfsmount when coming from NFSD |
| */ |
| if (mnt && |
| ((mnt->mnt_flags & MNT_NOATIME) || |
| ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))) |
| return; |
| |
| now = current_fs_time(inode->i_sb); |
| if (!timespec_equal(&inode->i_atime, &now)) { |
| inode->i_atime = now; |
| mark_inode_dirty_sync(inode); |
| } |
| } |
| |
| 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_NOCTIME 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_dentry->d_inode; |
| struct timespec now; |
| int sync_it = 0; |
| |
| if (IS_NOCMTIME(inode)) |
| return; |
| if (IS_RDONLY(inode)) |
| return; |
| |
| now = current_fs_time(inode->i_sb); |
| if (!timespec_equal(&inode->i_mtime, &now)) |
| sync_it = 1; |
| inode->i_mtime = now; |
| |
| if (!timespec_equal(&inode->i_ctime, &now)) |
| sync_it = 1; |
| inode->i_ctime = now; |
| |
| if (sync_it) |
| mark_inode_dirty_sync(inode); |
| } |
| |
| 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); |
| |
| /* |
| * Quota functions that want to walk the inode lists.. |
| */ |
| #ifdef CONFIG_QUOTA |
| |
| /* Function back in dquot.c */ |
| int remove_inode_dquot_ref(struct inode *, int, struct list_head *); |
| |
| void remove_dquot_ref(struct super_block *sb, int type, |
| struct list_head *tofree_head) |
| { |
| struct inode *inode; |
| |
| if (!sb->dq_op) |
| return; /* nothing to do */ |
| spin_lock(&inode_lock); /* This lock is for inodes code */ |
| |
| /* |
| * We don't have to lock against quota code - test IS_QUOTAINIT is |
| * just for speedup... |
| */ |
| list_for_each_entry(inode, &sb->s_inodes, i_sb_list) |
| if (!IS_NOQUOTA(inode)) |
| remove_inode_dquot_ref(inode, type, tofree_head); |
| |
| spin_unlock(&inode_lock); |
| } |
| |
| #endif |
| |
| int inode_wait(void *word) |
| { |
| schedule(); |
| return 0; |
| } |
| |
| /* |
| * 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_LOCK 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_LOCK); |
| wq = bit_waitqueue(&inode->i_state, __I_LOCK); |
| prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
| spin_unlock(&inode_lock); |
| schedule(); |
| finish_wait(wq, &wait.wait); |
| spin_lock(&inode_lock); |
| } |
| |
| void wake_up_inode(struct inode *inode) |
| { |
| /* |
| * Prevent speculative execution through spin_unlock(&inode_lock); |
| */ |
| smp_mb(); |
| wake_up_bit(&inode->i_state, __I_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(unsigned long mempages) |
| { |
| int loop; |
| |
| /* inode slab cache */ |
| inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode), |
| 0, SLAB_RECLAIM_ACCOUNT|SLAB_PANIC, init_once, NULL); |
| set_shrinker(DEFAULT_SEEKS, shrink_icache_memory); |
| |
| /* 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)\n", |
| mode); |
| } |
| EXPORT_SYMBOL(init_special_inode); |