/*
* (C) 1997 Linus Torvalds
* (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation)
*/
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include <linux/hash.h>
#include <linux/swap.h>
#include <linux/security.h>
#include <linux/cdev.h>
#include <linux/bootmem.h>
#include <linux/fsnotify.h>
#include <linux/mount.h>
#include <linux/posix_acl.h>
#include <linux/prefetch.h>
#include <linux/buffer_head.h> /* for inode_has_buffers */
#include <linux/ratelimit.h>
#include <linux/list_lru.h>
#include "internal.h"
/*
* Inode locking rules:
*
* inode->i_lock protects:
* inode->i_state, inode->i_hash, __iget()
* Inode LRU list locks protect:
* inode->i_sb->s_inode_lru, inode->i_lru
* inode_sb_list_lock protects:
* sb->s_inodes, inode->i_sb_list
* bdi->wb.list_lock protects:
* bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list
* inode_hash_lock protects:
* inode_hashtable, inode->i_hash
*
* Lock ordering:
*
* inode_sb_list_lock
* inode->i_lock
* Inode LRU list locks
*
* bdi->wb.list_lock
* inode->i_lock
*
* inode_hash_lock
* inode_sb_list_lock
* inode->i_lock
*
* iunique_lock
* inode_hash_lock
*/
static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
static struct hlist_head *inode_hashtable __read_mostly;
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock);
/*
* Empty aops. Can be used for the cases where the user does not
* define any of the address_space operations.
*/
const struct address_space_operations empty_aops = {
};
EXPORT_SYMBOL(empty_aops);
/*
* Statistics gathering..
*/
struct inodes_stat_t inodes_stat;
static DEFINE_PER_CPU(unsigned long, nr_inodes);
static DEFINE_PER_CPU(unsigned long, nr_unused);
static struct kmem_cache *inode_cachep __read_mostly;
static long get_nr_inodes(void)
{
int i;
long sum = 0;
for_each_possible_cpu(i)
sum += per_cpu(nr_inodes, i);
return sum < 0 ? 0 : sum;
}
static inline long get_nr_inodes_unused(void)
{
int i;
long sum = 0;
for_each_possible_cpu(i)
sum += per_cpu(nr_unused, i);
return sum < 0 ? 0 : sum;
}
long get_nr_dirty_inodes(void)
{
/* not actually dirty inodes, but a wild approximation */
long nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
return nr_dirty > 0 ? nr_dirty : 0;
}
/*
* Handle nr_inode sysctl
*/
#ifdef CONFIG_SYSCTL
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();
inodes_stat.nr_unused = get_nr_inodes_unused();
return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
}
#endif
/**
* 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 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_opflags = 0;
i_uid_write(inode, 0);
i_gid_write(inode, 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);
atomic_set(&inode->i_dio_count, 0);
mapping->a_ops = &empty_aops;
mapping->host = inode;
mapping->flags = 0;
mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
mapping->private_data = 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;
INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
#ifdef CONFIG_FS_POSIX_ACL
inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
#endif
#ifdef CONFIG_FSNOTIFY
inode->i_fsnotify_mask = 0;
#endif
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);
if (!inode->i_nlink) {
WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
atomic_long_dec(&inode->i_sb->s_remove_count);
}
#ifdef CONFIG_FS_POSIX_ACL
if (inode->i_acl && 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);
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);
}
/**
* drop_nlink - directly drop an inode's link count
* @inode: inode
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink. In cases
* where we are attempting to track writes to the
* filesystem, a decrement to zero means an imminent
* write when the file is truncated and actually unlinked
* on the filesystem.
*/
void drop_nlink(struct inode *inode)
{
WARN_ON(inode->i_nlink == 0);
inode->__i_nlink--;
if (!inode->i_nlink)
atomic_long_inc(&inode->i_sb->s_remove_count);
}
EXPORT_SYMBOL(drop_nlink);
/**
* clear_nlink - directly zero an inode's link count
* @inode: inode
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink. See
* drop_nlink() for why we care about i_nlink hitting zero.
*/
void clear_nlink(struct inode *inode)
{
if (inode->i_nlink) {
inode->__i_nlink = 0;
atomic_long_inc(&inode->i_sb->s_remove_count);
}
}
EXPORT_SYMBOL(clear_nlink);
/**
* set_nlink - directly set an inode's link count
* @inode: inode
* @nlink: new nlink (should be non-zero)
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink.
*/
void set_nlink(struct inode *inode, unsigned int nlink)
{
if (!nlink) {
clear_nlink(inode);
} else {
/* Yes, some filesystems do change nlink from zero to one */
if (inode->i_nlink == 0)
atomic_long_dec(&inode->i_sb->s_remove_count);
inode->__i_nlink = nlink;
}
}
EXPORT_SYMBOL(set_nlink);
/**
* inc_nlink - directly increment an inode's link count
* @inode: inode
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink. Currently,
* it is only here for parity with dec_nlink().
*/
void inc_nlink(struct inode *inode)
{
if (unlikely(inode->i_nlink == 0)) {
WARN_ON(!(inode->i_state & I_LINKABLE));
atomic_long_dec(&inode->i_sb->s_remove_count);
}
inode->__i_nlink++;
}
EXPORT_SYMBOL(inc_nlink);
void address_space_init_once(struct address_space *mapping)
{
memset(mapping, 0, sizeof(*mapping));
INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
spin_lock_init(&mapping->tree_lock);
mutex_init(&mapping->i_mmap_mutex);
INIT_LIST_HEAD(&mapping->private_list);
spin_lock_init(&mapping->private_lock);
mapping->i_mmap = RB_ROOT;
INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
}
EXPORT_SYMBOL(address_space_init_once);
/*
* These are initializations that only need to be done
* once, because the fields are idempotent across use
* of the inode, so let the slab aware of that.
*/
void inode_init_once(struct inode *inode)
{
memset(inode, 0, sizeof(*inode));
INIT_HLIST_NODE(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_devices);
INIT_LIST_HEAD(&inode->i_wb_list);
INIT_LIST_HEAD(&inode->i_lru);
address_space_init_once(&inode->i_data);
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->i_lock must be held
*/
void __iget(struct inode *inode)
{
atomic_inc(&inode->i_count);
}
/*
* get additional reference to inode; caller must already hold one.
*/
void ihold(struct inode *inode)
{
WARN_ON(atomic_inc_return(&inode->i_count) < 2);
}
EXPORT_SYMBOL(ihold);
static void inode_lru_list_add(struct inode *inode)
{
if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
this_cpu_inc(nr_unused);
}
/*
* Add inode to LRU if needed (inode is unused and clean).
*
* Needs inode->i_lock held.
*/
void inode_add_lru(struct inode *inode)
{
if (!(inode->i_state & (I_DIRTY | I_SYNC | I_FREEING | I_WILL_FREE)) &&
!atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE)
inode_lru_list_add(inode);
}
static void inode_lru_list_del(struct inode *inode)
{
if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
this_cpu_dec(nr_unused);
}
/**
* inode_sb_list_add - add inode to the superblock list of inodes
* @inode: inode to add
*/
void inode_sb_list_add(struct inode *inode)
{
spin_lock(&inode_sb_list_lock);
list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
spin_unlock(&inode_sb_list_lock);
}
EXPORT_SYMBOL_GPL(inode_sb_list_add);
static inline void inode_sb_list_del(struct inode *inode)
{
if (!list_empty(&inode->i_sb_list)) {
spin_lock(&inode_sb_list_lock);
list_del_init(&inode->i_sb_list);
spin_unlock(&inode_sb_list_lock);
}
}
static unsigned long hash(struct super_block *sb, unsigned long hashval)
{
unsigned long tmp;
tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
L1_CACHE_BYTES;
tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
return tmp & i_hash_mask;
}
/**
* __insert_inode_hash - hash an inode
* @inode: unhashed inode
* @hashval: unsigned long value used to locate this object in the
* inode_hashtable.
*
* Add an inode to the inode hash for this superblock.
*/
void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
spin_lock(&inode_hash_lock);
spin_lock(&inode->i_lock);
hlist_add_head(&inode->i_hash, b);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);
/**
* __remove_inode_hash - remove an inode from the hash
* @inode: inode to unhash
*
* Remove an inode from the superblock.
*/
void __remove_inode_hash(struct inode *inode)
{
spin_lock(&inode_hash_lock);
spin_lock(&inode->i_lock);
hlist_del_init(&inode->i_hash);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__remove_inode_hash);
void clear_inode(struct inode *inode)
{
might_sleep();
/*
* We have to cycle tree_lock here because reclaim can be still in the
* process of removing the last page (in __delete_from_page_cache())
* and we must not free mapping under it.
*/
spin_lock_irq(&inode->i_data.tree_lock);
BUG_ON(inode->i_data.nrpages);
spin_unlock_irq(&inode->i_data.tree_lock);
BUG_ON(!list_empty(&inode->i_data.private_list));
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(inode->i_state & I_CLEAR);
/* don't need i_lock here, no concurrent mods to i_state */
inode->i_state = I_FREEING | I_CLEAR;
}
EXPORT_SYMBOL(clear_inode);
/*
* Free the inode passed in, removing it from the lists it is still connected
* to. We remove any pages still attached to the inode and wait for any IO that
* is still in progress before finally destroying the inode.
*
* An inode must already be marked I_FREEING so that we avoid the inode being
* moved back onto lists if we race with other code that manipulates the lists
* (e.g. writeback_single_inode). The caller is responsible for setting this.
*
* An inode must already be removed from the LRU list before being evicted from
* the cache. This should occur atomically with setting the I_FREEING state
* flag, so no inodes here should ever be on the LRU when being evicted.
*/
static void evict(struct inode *inode)
{
const struct super_operations *op = inode->i_sb->s_op;
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(!list_empty(&inode->i_lru));
if (!list_empty(&inode->i_wb_list))
inode_wb_list_del(inode);
inode_sb_list_del(inode);
/*
* Wait for flusher thread to be done with the inode so that filesystem
* does not start destroying it while writeback is still running. Since
* the inode has I_FREEING set, flusher thread won't start new work on
* the inode. We just have to wait for running writeback to finish.
*/
inode_wait_for_writeback(inode);
if (op->evict_inode) {
op->evict_inode(inode);
} else {
if (inode->i_data.nrpages)
truncate_inode_pages(&inode->i_data, 0);
clear_inode(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);
remove_inode_hash(inode);
spin_lock(&inode->i_lock);
wake_up_bit(&inode->i_state, __I_NEW);
BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
spin_unlock(&inode->i_lock);
destroy_inode(inode);
}
/*
* dispose_list - dispose of the contents of a local list
* @head: the head of the list to free
*
* Dispose-list gets a local list with local inodes in it, so it doesn't
* need to worry about list corruption and SMP locks.
*/
static void dispose_list(struct list_head *head)
{
while (!list_empty(head)) {
struct inode *inode;
inode = list_first_entry(head, struct inode, i_lru);
list_del_init(&inode->i_lru);
evict(inode);
}
}
/**
* 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);
spin_lock(&inode_sb_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
if (atomic_read(&inode->i_count))
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
spin_unlock(&inode->i_lock);
continue;
}
inode->i_state |= I_FREEING;
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
list_add(&inode->i_lru, &dispose);
}
spin_unlock(&inode_sb_list_lock);
dispose_list(&dispose);
}
/**
* invalidate_inodes - attempt to free all inodes on a superblock
* @sb: superblock to operate on
* @kill_dirty: flag to guide handling of dirty inodes
*
* Attempts to free all inodes for a given superblock. If there were any
* busy inodes return a non-zero value, else zero.
* If @kill_dirty is set, discard dirty inodes too, otherwise treat
* them as busy.
*/
int invalidate_inodes(struct super_block *sb, bool kill_dirty)
{
int busy = 0;
struct inode *inode, *next;
LIST_HEAD(dispose);
spin_lock(&inode_sb_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
spin_unlock(&inode->i_lock);
continue;
}
if (inode->i_state & I_DIRTY && !kill_dirty) {
spin_unlock(&inode->i_lock);
busy = 1;
continue;
}
if (atomic_read(&inode->i_count)) {
spin_unlock(&inode->i_lock);
busy = 1;
continue;
}
inode->i_state |= I_FREEING;
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
list_add(&inode->i_lru, &dispose);
}
spin_unlock(&inode_sb_list_lock);
dispose_list(&dispose);
return busy;
}
/*
* Isolate the inode from the LRU in preparation for freeing it.
*
* 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 enum lru_status
inode_lru_isolate(struct list_head *item, spinlock_t *lru_lock, void *arg)
{
struct list_head *freeable = arg;
struct inode *inode = container_of(item, struct inode, i_lru);
/*
* we are inverting the lru lock/inode->i_lock here, so use a trylock.
* If we fail to get the lock, just skip it.
*/
if (!spin_trylock(&inode->i_lock))
return LRU_SKIP;
/*
* 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);
spin_unlock(&inode->i_lock);
this_cpu_dec(nr_unused);
return LRU_REMOVED;
}
/* recently referenced inodes get one more pass */
if (inode->i_state & I_REFERENCED) {
inode->i_state &= ~I_REFERENCED;
spin_unlock(&inode->i_lock);
return LRU_ROTATE;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(lru_lock);
if (remove_inode_buffers(inode)) {
unsigned long reap;
reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
if (current_is_kswapd())
__count_vm_events(KSWAPD_INODESTEAL, reap);
else
__count_vm_events(PGINODESTEAL, reap);
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += reap;
}
iput(inode);
spin_lock(lru_lock);
return LRU_RETRY;
}
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
list_move(&inode->i_lru, freeable);
spin_unlock(&inode->i_lock);
this_cpu_dec(nr_unused);
return LRU_REMOVED;
}
/*
* Walk the superblock inode LRU for freeable inodes and attempt to free them.
* This is called from the superblock shrinker function with a number of inodes
* to trim from the LRU. Inodes to be freed are moved to a temporary list and
* then are freed outside inode_lock by dispose_list().
*/
long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan,
int nid)
{
LIST_HEAD(freeable);
long freed;
freed = list_lru_walk_node(&sb->s_inode_lru, nid, inode_lru_isolate,
&freeable, &nr_to_scan);
dispose_list(&freeable);
return freed;
}
static void __wait_on_freeing_inode(struct inode *inode);
/*
* Called with the inode lock held.
*/
static struct inode *find_inode(struct super_block *sb,
struct hlist_head *head,
int (*test)(struct inode *, void *),
void *data)
{
struct inode *inode = NULL;
repeat:
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_sb != sb)
continue;
if (!test(inode, data))
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
__iget(inode);
spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
}
/*
* find_inode_fast is the fast path version of find_inode, see the comment at
* iget_locked for details.
*/
static struct inode *find_inode_fast(struct super_block *sb,
struct hlist_head *head, unsigned long ino)
{
struct inode *inode = NULL;
repeat:
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_ino != ino)
continue;
if (inode->i_sb != sb)
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
__iget(inode);
spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
}
/*
* Each cpu owns a range of LAST_INO_BATCH numbers.
* 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
* to renew the exhausted range.
*
* This does not significantly increase overflow rate because every CPU can
* consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
* NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
* 2^32 range, and is a worst-case. Even a 50% wastage would only increase
* overflow rate by 2x, which does not seem too significant.
*
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
* error if st_ino won't fit in target struct field. Use 32bit counter
* here to attempt to avoid that.
*/
#define LAST_INO_BATCH 1024
static DEFINE_PER_CPU(unsigned int, last_ino);
unsigned int get_next_ino(void)
{
unsigned int *p = &get_cpu_var(last_ino);
unsigned int res = *p;
#ifdef CONFIG_SMP
if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
static atomic_t shared_last_ino;
int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
res = next - LAST_INO_BATCH;
}
#endif
*p = ++res;
put_cpu_var(last_ino);
return res;
}
EXPORT_SYMBOL(get_next_ino);
/**
* new_inode_pseudo - obtain an inode
* @sb: superblock
*
* Allocates a new inode for given superblock.
* Inode wont be chained in superblock s_inodes list
* This means :
* - fs can't be unmount
* - quotas, fsnotify, writeback can't work
*/
struct inode *new_inode_pseudo(struct super_block *sb)
{
struct inode *inode = alloc_inode(sb);
if (inode) {
spin_lock(&inode->i_lock);
inode->i_state = 0;
spin_unlock(&inode->i_lock);
INIT_LIST_HEAD(&inode->i_sb_list);
}
return inode;
}
/**
* new_inode - obtain an inode
* @sb: superblock
*
* Allocates a new inode for given superblock. The default gfp_mask
* for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
* If HIGHMEM pages are unsuitable or it is known that pages allocated
* for the page cache are not reclaimable or migratable,
* mapping_set_gfp_mask() must be called with suitable flags on the
* newly created inode's mapping
*
*/
struct inode *new_inode(struct super_block *sb)
{
struct inode *inode;
spin_lock_prefetch(&inode_sb_list_lock);
inode = new_inode_pseudo(sb);
if (inode)
inode_sb_list_add(inode);
return inode;
}
EXPORT_SYMBOL(new_inode);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void lockdep_annotate_inode_mutex_key(struct inode *inode)
{
if (S_ISDIR(inode->i_mode)) {
struct file_system_type *type = inode->i_sb->s_type;
/* Set new key only if filesystem hasn't already changed it */
if (lockdep_match_class(&inode->i_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);
}
}
}
EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
#endif
/**
* unlock_new_inode - clear the I_NEW state and wake up any waiters
* @inode: new inode to unlock
*
* Called when the inode is fully initialised to clear the new state of the
* inode and wake up anyone waiting for the inode to finish initialisation.
*/
void unlock_new_inode(struct inode *inode)
{
lockdep_annotate_inode_mutex_key(inode);
spin_lock(&inode->i_lock);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW;
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(unlock_new_inode);
/**
* lock_two_nondirectories - take two i_mutexes on non-directory objects
* @inode1: first inode to lock
* @inode2: second inode to lock
*/
void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
if (inode1 == inode2 || !inode2) {
mutex_lock(&inode1->i_mutex);
return;
}
WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
if (inode1 < inode2) {
mutex_lock(&inode1->i_mutex);
mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
} else {
mutex_lock(&inode2->i_mutex);
mutex_lock_nested(&inode1->i_mutex, I_MUTEX_NONDIR2);
}
}
EXPORT_SYMBOL(lock_two_nondirectories);
/**
* unlock_two_nondirectories - release locks from lock_two_nondirectories()
* @inode1: first inode to unlock
* @inode2: second inode to unlock
*/
void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
mutex_unlock(&inode1->i_mutex);
if (inode2 && inode2 != inode1)
mutex_unlock(&inode2->i_mutex);
}
EXPORT_SYMBOL(unlock_two_nondirectories);
/**
* iget5_locked - obtain an inode from a mounted file system
* @sb: super block of file system
* @hashval: hash value (usually inode number) to get
* @test: callback used for comparisons between inodes
* @set: callback used to initialize a new struct inode
* @data: opaque data pointer to pass to @test and @set
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if present it is return it with an increased reference count. This is
* a generalized version of iget_locked() for file systems where the inode
* number is not sufficient for unique identification of an inode.
*
* If the inode is not in cache, allocate a new inode and return it locked,
* hashed, and with the I_NEW flag set. The file system gets to fill it in
* before unlocking it via unlock_new_inode().
*
* Note both @test and @set are called with the inode_hash_lock held, so can't
* sleep.
*/
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
struct inode *inode;
spin_lock(&inode_hash_lock);
inode = find_inode(sb, head, test, data);
spin_unlock(&inode_hash_lock);
if (inode) {
wait_on_inode(inode);
return inode;
}
inode = alloc_inode(sb);
if (inode) {
struct inode *old;
spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode(sb, head, test, data);
if (!old) {
if (set(inode, data))
goto set_failed;
spin_lock(&inode->i_lock);
inode->i_state = I_NEW;
hlist_add_head(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
inode_sb_list_add(inode);
spin_unlock(&inode_hash_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
*/
return inode;
}
/*
* Uhhuh, somebody else created the same inode under
* us. Use the old inode instead of the one we just
* allocated.
*/
spin_unlock(&inode_hash_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
}
return inode;
set_failed:
spin_unlock(&inode_hash_lock);
destroy_inode(inode);
return NULL;
}
EXPORT_SYMBOL(iget5_locked);
/**
* iget_locked - obtain an inode from a mounted file system
* @sb: super block of file system
* @ino: inode number to get
*
* Search for the inode specified by @ino in the inode cache and if present
* return it with an increased reference count. This is for file systems
* where the inode number is sufficient for unique identification of an inode.
*
* If the inode is not in cache, allocate a new inode and return it locked,
* hashed, and with the I_NEW flag set. The file system gets to fill it in
* before unlocking it via unlock_new_inode().
*/
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
spin_lock(&inode_hash_lock);
inode = find_inode_fast(sb, head, ino);
spin_unlock(&inode_hash_lock);
if (inode) {
wait_on_inode(inode);
return inode;
}
inode = alloc_inode(sb);
if (inode) {
struct inode *old;
spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode_fast(sb, head, ino);
if (!old) {
inode->i_ino = ino;
spin_lock(&inode->i_lock);
inode->i_state = I_NEW;
hlist_add_head(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
inode_sb_list_add(inode);
spin_unlock(&inode_hash_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
*/
return inode;
}
/*
* Uhhuh, somebody else created the same inode under
* us. Use the old inode instead of the one we just
* allocated.
*/
spin_unlock(&inode_hash_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
}
return inode;
}
EXPORT_SYMBOL(iget_locked);
/*
* search the inode cache for a matching inode number.
* If we find one, then the inode number we are trying to
* allocate is not unique and so we should not use it.
*
* Returns 1 if the inode number is unique, 0 if it is not.
*/
static int test_inode_iunique(struct super_block *sb, unsigned long ino)
{
struct hlist_head *b = inode_hashtable + hash(sb, ino);
struct inode *inode;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(inode, b, i_hash) {
if (inode->i_ino == ino && inode->i_sb == sb) {
spin_unlock(&inode_hash_lock);
return 0;
}
}
spin_unlock(&inode_hash_lock);
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(&iunique_lock);
do {
if (counter <= max_reserved)
counter = max_reserved + 1;
res = counter++;
} while (!test_inode_iunique(sb, res));
spin_unlock(&iunique_lock);
return res;
}
EXPORT_SYMBOL(iunique);
struct inode *igrab(struct inode *inode)
{
spin_lock(&inode->i_lock);
if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
__iget(inode);
spin_unlock(&inode->i_lock);
} else {
spin_unlock(&inode->i_lock);
/*
* Handle the case where s_op->clear_inode is not been
* called yet, and somebody is calling igrab
* while the inode is getting freed.
*/
inode = NULL;
}
return inode;
}
EXPORT_SYMBOL(igrab);
/**
* ilookup5_nowait - search for an inode in the inode cache
* @sb: super block of file system to search
* @hashval: hash value (usually inode number) to search for
* @test: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @test
*
* Search for the inode specified by @hashval and @data in the inode cache.
* If the inode is in the cache, the inode is returned with an incremented
* reference count.
*
* Note: I_NEW is not waited upon so you have to be very careful what you do
* with the returned inode. You probably should be using ilookup5() instead.
*
* Note2: @test is called with the inode_hash_lock held, so can't sleep.
*/
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
struct inode *inode;
spin_lock(&inode_hash_lock);
inode = find_inode(sb, head, test, data);
spin_unlock(&inode_hash_lock);
return inode;
}
EXPORT_SYMBOL(ilookup5_nowait);
/**
* ilookup5 - search for an inode in the inode cache
* @sb: super block of file system to search
* @hashval: hash value (usually inode number) to search for
* @test: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @test
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if the inode is in the cache, return the inode with an incremented
* reference count. Waits on I_NEW before returning the inode.
* returned with an incremented reference count.
*
* This is a generalized version of ilookup() for file systems where the
* inode number is not sufficient for unique identification of an inode.
*
* Note: @test is called with the inode_hash_lock held, so can't sleep.
*/
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
if (inode)
wait_on_inode(inode);
return inode;
}
EXPORT_SYMBOL(ilookup5);
/**
* ilookup - search for an inode in the inode cache
* @sb: super block of file system to search
* @ino: inode number to search for
*
* Search for the inode @ino in the inode cache, and if the inode is in the
* cache, the inode is returned with an incremented reference count.
*/
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
spin_lock(&inode_hash_lock);
inode = find_inode_fast(sb, head, ino);
spin_unlock(&inode_hash_lock);
if (inode)
wait_on_inode(inode);
return inode;
}
EXPORT_SYMBOL(ilookup);
int insert_inode_locked(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
struct hlist_head *head = inode_hashtable + hash(sb, ino);
while (1) {
struct inode *old = NULL;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, head, i_hash) {
if (old->i_ino != ino)
continue;
if (old->i_sb != sb)
continue;
spin_lock(&old->i_lock);
if (old->i_state & (I_FREEING|I_WILL_FREE)) {
spin_unlock(&old->i_lock);
continue;
}
break;
}
if (likely(!old)) {
spin_lock(&inode->i_lock);
inode->i_state |= I_NEW;
hlist_add_head(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
return 0;
}
__iget(old);
spin_unlock(&old->i_lock);
spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
return -EBUSY;
}
iput(old);
}
}
EXPORT_SYMBOL(insert_inode_locked);
int insert_inode_locked4(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct super_block *sb = inode->i_sb;
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
while (1) {
struct inode *old = NULL;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, head, i_hash) {
if (old->i_sb != sb)
continue;
if (!test(old, data))
continue;
spin_lock(&old->i_lock);
if (old->i_state & (I_FREEING|I_WILL_FREE)) {
spin_unlock(&old->i_lock);
continue;
}
break;
}
if (likely(!old)) {
spin_lock(&inode->i_lock);
inode->i_state |= I_NEW;
hlist_add_head(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
return 0;
}
__iget(old);
spin_unlock(&old->i_lock);
spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
return -EBUSY;
}
iput(old);
}
}
EXPORT_SYMBOL(insert_inode_locked4);
int generic_delete_inode(struct inode *inode)
{
return 1;
}
EXPORT_SYMBOL(generic_delete_inode);
/*
* Called when we're dropping the last reference
* to an inode.
*
* Call the FS "drop_inode()" function, defaulting to
* the legacy UNIX filesystem behaviour. If it tells
* us to evict inode, do so. Otherwise, retain inode
* in cache if fs is alive, sync and evict if fs is
* shutting down.
*/
static void iput_final(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
const struct super_operations *op = inode->i_sb->s_op;
int drop;
WARN_ON(inode->i_state & I_NEW);
if (op->drop_inode)
drop = op->drop_inode(inode);
else
drop = generic_drop_inode(inode);
if (!drop && (sb->s_flags & MS_ACTIVE)) {
inode->i_state |= I_REFERENCED;
inode_add_lru(inode);
spin_unlock(&inode->i_lock);
return;
}
if (!drop) {
inode->i_state |= I_WILL_FREE;
spin_unlock(&inode->i_lock);
write_inode_now(inode, 1);
spin_lock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
}
inode->i_state |= I_FREEING;
if (!list_empty(&inode->i_lru))
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
evict(inode);
}
/**
* iput - put an inode
* @inode: inode to put
*
* Puts an inode, dropping its usage count. If the inode use count hits
* zero, the inode is then freed and may also be destroyed.
*
* Consequently, iput() can sleep.
*/
void iput(struct inode *inode)
{
if (inode) {
BUG_ON(inode->i_state & I_CLEAR);
if (atomic_dec_and_lock(&inode->i_count, &inode->i_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;
}
/*
* This does the actual work of updating an inodes time or version. Must have
* had called mnt_want_write() before calling this.
*/
static int update_time(struct inode *inode, struct timespec *time, int flags)
{
if (inode->i_op->update_time)
return inode->i_op->update_time(inode, time, flags);
if (flags & S_ATIME)
inode->i_atime = *time;
if (flags & S_VERSION)
inode_inc_iversion(inode);
if (flags & S_CTIME)
inode->i_ctime = *time;
if (flags & S_MTIME)
inode->i_mtime = *time;
mark_inode_dirty_sync(inode);
return 0;
}
/**
* touch_atime - update the access time
* @path: the &struct path to update
*
* Update the accessed time on an inode and mark it for writeback.
* This function automatically handles read only file systems and media,
* as well as the "noatime" flag and inode specific "noatime" markers.
*/
void touch_atime(const struct path *path)
{
struct vfsmount *mnt = path->mnt;
struct inode *inode = path->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 (!sb_start_write_trylock(inode->i_sb))
return;
if (__mnt_want_write(mnt))
goto skip_update;
/*
* File systems can error out when updating inodes if they need to
* allocate new space to modify an inode (such is the case for
* Btrfs), but since we touch atime while walking down the path we
* really don't care if we failed to update the atime of the file,
* so just ignore the return value.
* We may also fail on filesystems that have the ability to make parts
* of the fs read only, e.g. subvolumes in Btrfs.
*/
update_time(inode, &now, S_ATIME);
__mnt_drop_write(mnt);
skip_update:
sb_end_write(inode->i_sb);
}
EXPORT_SYMBOL(touch_atime);
/*
* The logic we want is
*
* if suid or (sgid and xgrp)
* remove privs
*/
int should_remove_suid(struct dentry *dentry)
{
umode_t mode = dentry->d_inode->i_mode;
int kill = 0;
/* suid always must be killed */
if (unlikely(mode & S_ISUID))
kill = ATTR_KILL_SUID;
/*
* sgid without any exec bits is just a mandatory locking mark; leave
* it alone. If some exec bits are set, it's a real sgid; kill it.
*/
if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
kill |= ATTR_KILL_SGID;
if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
return kill;
return 0;
}
EXPORT_SYMBOL(should_remove_suid);
static int __remove_suid(struct dentry *dentry, int kill)
{
struct iattr newattrs;
newattrs.ia_valid = ATTR_FORCE | kill;
/*
* Note we call this on write, so notify_change will not
* encounter any conflicting delegations:
*/
return notify_change(dentry, &newattrs, NULL);
}
int file_remove_suid(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
int killsuid;
int killpriv;
int error = 0;
/* Fast path for nothing security related */
if (IS_NOSEC(inode))
return 0;
killsuid = should_remove_suid(dentry);
killpriv = security_inode_need_killpriv(dentry);
if (killpriv < 0)
return killpriv;
if (killpriv)
error = security_inode_killpriv(dentry);
if (!error && killsuid)
error = __remove_suid(dentry, killsuid);
if (!error && (inode->i_sb->s_flags & MS_NOSEC))
inode->i_flags |= S_NOSEC;
return error;
}
EXPORT_SYMBOL(file_remove_suid);
/**
* 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. This can return an error for
* file systems who need to allocate space in order to update an inode.
*/
int file_update_time(struct file *file)
{
struct inode *inode = file_inode(file);
struct timespec now;
int sync_it = 0;
int ret;
/* First try to exhaust all avenues to not sync */
if (IS_NOCMTIME(inode))
return 0;
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 0;
/* Finally allowed to write? Takes lock. */
if (__mnt_want_write_file(file))
return 0;
ret = update_time(inode, &now, sync_it);
__mnt_drop_write_file(file);
return ret;
}
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_bit(&inode->i_state, __I_NEW) after removing from the hash list
* will DTRT.
*/
static void __wait_on_freeing_inode(struct inode *inode)
{
wait_queue_head_t *wq;
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
schedule();
finish_wait(wq, &wait.wait);
spin_lock(&inode_hash_lock);
}
static __initdata unsigned long ihash_entries;
static int __init set_ihash_entries(char *str)
{
if (!str)
return 0;
ihash_entries = simple_strtoul(str, &str, 0);
return 1;
}
__setup("ihash_entries=", set_ihash_entries);
/*
* Initialize the waitqueues and inode hash table.
*/
void __init inode_init_early(void)
{
unsigned 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,
0);
for (loop = 0; loop < (1U << i_hash_shift); loop++)
INIT_HLIST_HEAD(&inode_hashtable[loop]);
}
void __init inode_init(void)
{
unsigned 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);
/* 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,
0);
for (loop = 0; loop < (1U << 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 = &pipefifo_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);
/**
* inode_init_owner - 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,
umode_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);
/**
* inode_owner_or_capable - check current task permissions to inode
* @inode: inode being checked
*
* Return true if current either has CAP_FOWNER to the inode, or
* owns the file.
*/
bool inode_owner_or_capable(const struct inode *inode)
{
if (uid_eq(current_fsuid(), inode->i_uid))
return true;
if (inode_capable(inode, CAP_FOWNER))
return true;
return false;
}
EXPORT_SYMBOL(inode_owner_or_capable);
/*
* Direct i/o helper functions
*/
static void __inode_dio_wait(struct inode *inode)
{
wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
do {
prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE);
if (atomic_read(&inode->i_dio_count))
schedule();
} while (atomic_read(&inode->i_dio_count));
finish_wait(wq, &q.wait);
}
/**
* inode_dio_wait - wait for outstanding DIO requests to finish
* @inode: inode to wait for
*
* Waits for all pending direct I/O requests to finish so that we can
* proceed with a truncate or equivalent operation.
*
* Must be called under a lock that serializes taking new references
* to i_dio_count, usually by inode->i_mutex.
*/
void inode_dio_wait(struct inode *inode)
{
if (atomic_read(&inode->i_dio_count))
__inode_dio_wait(inode);
}
EXPORT_SYMBOL(inode_dio_wait);
/*
* inode_dio_done - signal finish of a direct I/O requests
* @inode: inode the direct I/O happens on
*
* This is called once we've finished processing a direct I/O request,
* and is used to wake up callers waiting for direct I/O to be quiesced.
*/
void inode_dio_done(struct inode *inode)
{
if (atomic_dec_and_test(&inode->i_dio_count))
wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
}
EXPORT_SYMBOL(inode_dio_done);