/* * 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 __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. */ LIST_HEAD(inode_in_use);LIST_HEAD(inode_unused);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_mutex 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. */static DEFINE_MUTEX(iprune_mutex); /* * Statistics gathering.. */struct inodes_stat_t inodes_stat; static kmem_cache_t * inode_cachep __read_mostly; static struct inode *alloc_inode(struct super_block *sb){ static struct address_space_operations empty_aops; static struct inode_operations empty_iops; static const 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) { BUG_ON(inode_has_buffers(inode)); 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); BUG_ON(inode->i_data.nrpages); BUG_ON(!(inode->i_state & I_FREEING)); BUG_ON(inode->i_state & I_CLEAR); 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_mutex 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); mutex_lock(&iprune_mutex); 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); mutex_unlock(&iprune_mutex); 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 mutex 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; mutex_lock(&iprune_mutex); 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); mutex_unlock(&iprune_mutex); 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;Lines 1–500 of 1417. Load more
/* * 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 __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. */ LIST_HEAD(inode_in_use); LIST_HEAD(inode_unused); 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_mutex 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. */ static DEFINE_MUTEX(iprune_mutex); /* * Statistics gathering.. */ struct inodes_stat_t inodes_stat; static kmem_cache_t * inode_cachep __read_mostly; static struct inode *alloc_inode(struct super_block *sb) { static struct address_space_operations empty_aops; static struct inode_operations empty_iops; static const 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) { BUG_ON(inode_has_buffers(inode)); 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); BUG_ON(inode->i_data.nrpages); BUG_ON(!(inode->i_state & I_FREEING)); BUG_ON(inode->i_state & I_CLEAR); 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_mutex 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); mutex_lock(&iprune_mutex); 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); mutex_unlock(&iprune_mutex); 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 mutex 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; mutex_lock(&iprune_mutex); 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); mutex_unlock(&iprune_mutex); 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;