2
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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 13:43:55 +08:00
linux-next/fs/inode.c
Linus Torvalds b12a9124ee y2038: more syscalls and cleanups
This concludes the main part of the system call rework for 64-bit time_t,
 which has spread over most of year 2018, the last six system calls being
 
  - ppoll
  - pselect6
  - io_pgetevents
  - recvmmsg
  - futex
  - rt_sigtimedwait
 
 As before, nothing changes for 64-bit architectures, while 32-bit
 architectures gain another entry point that differs only in the layout
 of the timespec structure. Hopefully in the next release we can wire up
 all 22 of those system calls on all 32-bit architectures, which gives
 us a baseline version for glibc to start using them.
 
 This does not include the clock_adjtime, getrusage/waitid, and
 getitimer/setitimer system calls. I still plan to have new versions
 of those as well, but they are not required for correct operation of
 the C library since they can be emulated using the old 32-bit time_t
 based system calls.
 
 Aside from the system calls, there are also a few cleanups here,
 removing old kernel internal interfaces that have become unused after
 all references got removed. The arch/sh cleanups are part of this,
 there were posted several times over the past year without a reaction
 from the maintainers, while the corresponding changes made it into all
 other architectures.
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Merge tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git/arnd/playground

Pull y2038 updates from Arnd Bergmann:
 "More syscalls and cleanups

  This concludes the main part of the system call rework for 64-bit
  time_t, which has spread over most of year 2018, the last six system
  calls being

    - ppoll
    - pselect6
    - io_pgetevents
    - recvmmsg
    - futex
    - rt_sigtimedwait

  As before, nothing changes for 64-bit architectures, while 32-bit
  architectures gain another entry point that differs only in the layout
  of the timespec structure. Hopefully in the next release we can wire
  up all 22 of those system calls on all 32-bit architectures, which
  gives us a baseline version for glibc to start using them.

  This does not include the clock_adjtime, getrusage/waitid, and
  getitimer/setitimer system calls. I still plan to have new versions of
  those as well, but they are not required for correct operation of the
  C library since they can be emulated using the old 32-bit time_t based
  system calls.

  Aside from the system calls, there are also a few cleanups here,
  removing old kernel internal interfaces that have become unused after
  all references got removed. The arch/sh cleanups are part of this,
  there were posted several times over the past year without a reaction
  from the maintainers, while the corresponding changes made it into all
  other architectures"

* tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git/arnd/playground:
  timekeeping: remove obsolete time accessors
  vfs: replace current_kernel_time64 with ktime equivalent
  timekeeping: remove timespec_add/timespec_del
  timekeeping: remove unused {read,update}_persistent_clock
  sh: remove board_time_init() callback
  sh: remove unused rtc_sh_get/set_time infrastructure
  sh: sh03: rtc: push down rtc class ops into driver
  sh: dreamcast: rtc: push down rtc class ops into driver
  y2038: signal: Add compat_sys_rt_sigtimedwait_time64
  y2038: signal: Add sys_rt_sigtimedwait_time32
  y2038: socket: Add compat_sys_recvmmsg_time64
  y2038: futex: Add support for __kernel_timespec
  y2038: futex: Move compat implementation into futex.c
  io_pgetevents: use __kernel_timespec
  pselect6: use __kernel_timespec
  ppoll: use __kernel_timespec
  signal: Add restore_user_sigmask()
  signal: Add set_user_sigmask()
2018-12-28 12:45:04 -08:00

2164 lines
57 KiB
C

/*
* (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/memblock.h>
#include <linux/fsnotify.h>
#include <linux/mount.h>
#include <linux/posix_acl.h>
#include <linux/prefetch.h>
#include <linux/buffer_head.h> /* for inode_has_buffers */
#include <linux/ratelimit.h>
#include <linux/list_lru.h>
#include <linux/iversion.h>
#include <trace/events/writeback.h>
#include "internal.h"
/*
* Inode locking rules:
*
* inode->i_lock protects:
* inode->i_state, inode->i_hash, __iget()
* Inode LRU list locks protect:
* inode->i_sb->s_inode_lru, inode->i_lru
* inode->i_sb->s_inode_list_lock protects:
* inode->i_sb->s_inodes, inode->i_sb_list
* bdi->wb.list_lock protects:
* bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list
* inode_hash_lock protects:
* inode_hashtable, inode->i_hash
*
* Lock ordering:
*
* inode->i_sb->s_inode_list_lock
* inode->i_lock
* Inode LRU list locks
*
* bdi->wb.list_lock
* inode->i_lock
*
* inode_hash_lock
* inode->i_sb->s_inode_list_lock
* inode->i_lock
*
* iunique_lock
* inode_hash_lock
*/
static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
static struct hlist_head *inode_hashtable __read_mostly;
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
/*
* Empty aops. Can be used for the cases where the user does not
* define any of the address_space operations.
*/
const struct address_space_operations empty_aops = {
};
EXPORT_SYMBOL(empty_aops);
/*
* 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(struct 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
static int no_open(struct inode *inode, struct file *file)
{
return -ENXIO;
}
/**
* inode_init_always - perform inode structure initialisation
* @sb: superblock inode belongs to
* @inode: inode to initialise
*
* These are initializations that need to be done on every inode
* allocation as the fields are not initialised by slab allocation.
*/
int inode_init_always(struct super_block *sb, struct inode *inode)
{
static const struct inode_operations empty_iops;
static const struct file_operations no_open_fops = {.open = no_open};
struct address_space *const mapping = &inode->i_data;
inode->i_sb = sb;
inode->i_blkbits = sb->s_blocksize_bits;
inode->i_flags = 0;
atomic_set(&inode->i_count, 1);
inode->i_op = &empty_iops;
inode->i_fop = &no_open_fops;
inode->__i_nlink = 1;
inode->i_opflags = 0;
if (sb->s_xattr)
inode->i_opflags |= IOP_XATTR;
i_uid_write(inode, 0);
i_gid_write(inode, 0);
atomic_set(&inode->i_writecount, 0);
inode->i_size = 0;
inode->i_write_hint = WRITE_LIFE_NOT_SET;
inode->i_blocks = 0;
inode->i_bytes = 0;
inode->i_generation = 0;
inode->i_pipe = NULL;
inode->i_bdev = NULL;
inode->i_cdev = NULL;
inode->i_link = NULL;
inode->i_dir_seq = 0;
inode->i_rdev = 0;
inode->dirtied_when = 0;
#ifdef CONFIG_CGROUP_WRITEBACK
inode->i_wb_frn_winner = 0;
inode->i_wb_frn_avg_time = 0;
inode->i_wb_frn_history = 0;
#endif
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);
init_rwsem(&inode->i_rwsem);
lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key);
atomic_set(&inode->i_dio_count, 0);
mapping->a_ops = &empty_aops;
mapping->host = inode;
mapping->flags = 0;
mapping->wb_err = 0;
atomic_set(&mapping->i_mmap_writable, 0);
mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
mapping->private_data = NULL;
mapping->writeback_index = 0;
inode->i_private = NULL;
inode->i_mapping = mapping;
INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
#ifdef CONFIG_FS_POSIX_ACL
inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
#endif
#ifdef CONFIG_FSNOTIFY
inode->i_fsnotify_mask = 0;
#endif
inode->i_flctx = NULL;
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));
inode_detach_wb(inode);
security_inode_free(inode);
fsnotify_inode_delete(inode);
locks_free_lock_context(inode);
if (!inode->i_nlink) {
WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
atomic_long_dec(&inode->i_sb->s_remove_count);
}
#ifdef CONFIG_FS_POSIX_ACL
if (inode->i_acl && !is_uncached_acl(inode->i_acl))
posix_acl_release(inode->i_acl);
if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl))
posix_acl_release(inode->i_default_acl);
#endif
this_cpu_dec(nr_inodes);
}
EXPORT_SYMBOL(__destroy_inode);
static void 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);
static void __address_space_init_once(struct address_space *mapping)
{
xa_init_flags(&mapping->i_pages, XA_FLAGS_LOCK_IRQ);
init_rwsem(&mapping->i_mmap_rwsem);
INIT_LIST_HEAD(&mapping->private_list);
spin_lock_init(&mapping->private_lock);
mapping->i_mmap = RB_ROOT_CACHED;
}
void address_space_init_once(struct address_space *mapping)
{
memset(mapping, 0, sizeof(*mapping));
__address_space_init_once(mapping);
}
EXPORT_SYMBOL(address_space_init_once);
/*
* These are initializations that only need to be done
* once, because the fields are idempotent across use
* of the inode, so let the slab aware of that.
*/
void inode_init_once(struct inode *inode)
{
memset(inode, 0, sizeof(*inode));
INIT_HLIST_NODE(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_devices);
INIT_LIST_HEAD(&inode->i_io_list);
INIT_LIST_HEAD(&inode->i_wb_list);
INIT_LIST_HEAD(&inode->i_lru);
__address_space_init_once(&inode->i_data);
i_size_ordered_init(inode);
}
EXPORT_SYMBOL(inode_init_once);
static void init_once(void *foo)
{
struct inode *inode = (struct inode *) foo;
inode_init_once(inode);
}
/*
* inode->i_lock must be held
*/
void __iget(struct inode *inode)
{
atomic_inc(&inode->i_count);
}
/*
* get additional reference to inode; caller must already hold one.
*/
void ihold(struct inode *inode)
{
WARN_ON(atomic_inc_return(&inode->i_count) < 2);
}
EXPORT_SYMBOL(ihold);
static void inode_lru_list_add(struct inode *inode)
{
if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
this_cpu_inc(nr_unused);
else
inode->i_state |= I_REFERENCED;
}
/*
* Add inode to LRU if needed (inode is unused and clean).
*
* Needs inode->i_lock held.
*/
void inode_add_lru(struct inode *inode)
{
if (!(inode->i_state & (I_DIRTY_ALL | I_SYNC |
I_FREEING | I_WILL_FREE)) &&
!atomic_read(&inode->i_count) && inode->i_sb->s_flags & SB_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->i_sb->s_inode_list_lock);
list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
spin_unlock(&inode->i_sb->s_inode_list_lock);
}
EXPORT_SYMBOL_GPL(inode_sb_list_add);
static inline void inode_sb_list_del(struct inode *inode)
{
if (!list_empty(&inode->i_sb_list)) {
spin_lock(&inode->i_sb->s_inode_list_lock);
list_del_init(&inode->i_sb_list);
spin_unlock(&inode->i_sb->s_inode_list_lock);
}
}
static unsigned long hash(struct super_block *sb, unsigned long hashval)
{
unsigned long tmp;
tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
L1_CACHE_BYTES;
tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
return tmp & i_hash_mask;
}
/**
* __insert_inode_hash - hash an inode
* @inode: unhashed inode
* @hashval: unsigned long value used to locate this object in the
* inode_hashtable.
*
* Add an inode to the inode hash for this superblock.
*/
void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
spin_lock(&inode_hash_lock);
spin_lock(&inode->i_lock);
hlist_add_head(&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)
{
/*
* We have to cycle the i_pages lock here because reclaim can be in the
* process of removing the last page (in __delete_from_page_cache())
* and we must not free the mapping under it.
*/
xa_lock_irq(&inode->i_data.i_pages);
BUG_ON(inode->i_data.nrpages);
BUG_ON(inode->i_data.nrexceptional);
xa_unlock_irq(&inode->i_data.i_pages);
BUG_ON(!list_empty(&inode->i_data.private_list));
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(inode->i_state & I_CLEAR);
BUG_ON(!list_empty(&inode->i_wb_list));
/* don't need i_lock here, no concurrent mods to i_state */
inode->i_state = I_FREEING | I_CLEAR;
}
EXPORT_SYMBOL(clear_inode);
/*
* Free the inode passed in, removing it from the lists it is still connected
* to. We remove any pages still attached to the inode and wait for any IO that
* is still in progress before finally destroying the inode.
*
* An inode must already be marked I_FREEING so that we avoid the inode being
* moved back onto lists if we race with other code that manipulates the lists
* (e.g. writeback_single_inode). The caller is responsible for setting this.
*
* An inode must already be removed from the LRU list before being evicted from
* the cache. This should occur atomically with setting the I_FREEING state
* flag, so no inodes here should ever be on the LRU when being evicted.
*/
static void evict(struct inode *inode)
{
const struct super_operations *op = inode->i_sb->s_op;
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(!list_empty(&inode->i_lru));
if (!list_empty(&inode->i_io_list))
inode_io_list_del(inode);
inode_sb_list_del(inode);
/*
* Wait for flusher thread to be done with the inode so that filesystem
* does not start destroying it while writeback is still running. Since
* the inode has I_FREEING set, flusher thread won't start new work on
* the inode. We just have to wait for running writeback to finish.
*/
inode_wait_for_writeback(inode);
if (op->evict_inode) {
op->evict_inode(inode);
} else {
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
}
if (S_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);
cond_resched();
}
}
/**
* evict_inodes - evict all evictable inodes for a superblock
* @sb: superblock to operate on
*
* Make sure that no inodes with zero refcount are retained. This is
* called by superblock shutdown after having SB_ACTIVE flag removed,
* so any inode reaching zero refcount during or after that call will
* be immediately evicted.
*/
void evict_inodes(struct super_block *sb)
{
struct inode *inode, *next;
LIST_HEAD(dispose);
again:
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
if (atomic_read(&inode->i_count))
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
spin_unlock(&inode->i_lock);
continue;
}
inode->i_state |= I_FREEING;
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
list_add(&inode->i_lru, &dispose);
/*
* We can have a ton of inodes to evict at unmount time given
* enough memory, check to see if we need to go to sleep for a
* bit so we don't livelock.
*/
if (need_resched()) {
spin_unlock(&sb->s_inode_list_lock);
cond_resched();
dispose_list(&dispose);
goto again;
}
}
spin_unlock(&sb->s_inode_list_lock);
dispose_list(&dispose);
}
EXPORT_SYMBOL_GPL(evict_inodes);
/**
* invalidate_inodes - attempt to free all inodes on a superblock
* @sb: superblock to operate on
* @kill_dirty: flag to guide handling of dirty inodes
*
* Attempts to free all inodes for a given superblock. If there were any
* busy inodes return a non-zero value, else zero.
* If @kill_dirty is set, discard dirty inodes too, otherwise treat
* them as busy.
*/
int invalidate_inodes(struct super_block *sb, bool kill_dirty)
{
int busy = 0;
struct inode *inode, *next;
LIST_HEAD(dispose);
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
spin_unlock(&inode->i_lock);
continue;
}
if (inode->i_state & I_DIRTY_ALL && !kill_dirty) {
spin_unlock(&inode->i_lock);
busy = 1;
continue;
}
if (atomic_read(&inode->i_count)) {
spin_unlock(&inode->i_lock);
busy = 1;
continue;
}
inode->i_state |= I_FREEING;
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
list_add(&inode->i_lru, &dispose);
}
spin_unlock(&sb->s_inode_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,
struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
{
struct list_head *freeable = arg;
struct inode *inode = container_of(item, struct inode, i_lru);
/*
* we are inverting the lru lock/inode->i_lock here, so use a trylock.
* If we fail to get the lock, just skip it.
*/
if (!spin_trylock(&inode->i_lock))
return LRU_SKIP;
/*
* 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_lru_isolate(lru, &inode->i_lru);
spin_unlock(&inode->i_lock);
this_cpu_dec(nr_unused);
return LRU_REMOVED;
}
/*
* Recently referenced inodes and inodes with many attached pages
* get one more pass.
*/
if (inode->i_state & I_REFERENCED || inode->i_data.nrpages > 1) {
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_lru_isolate_move(lru, &inode->i_lru, freeable);
spin_unlock(&inode->i_lock);
this_cpu_dec(nr_unused);
return LRU_REMOVED;
}
/*
* Walk the superblock inode LRU for freeable inodes and attempt to free them.
* This is called from the superblock shrinker function with a number of inodes
* to trim from the LRU. Inodes to be freed are moved to a temporary list and
* then are freed outside inode_lock by dispose_list().
*/
long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
{
LIST_HEAD(freeable);
long freed;
freed = list_lru_shrink_walk(&sb->s_inode_lru, sc,
inode_lru_isolate, &freeable);
dispose_list(&freeable);
return freed;
}
static void __wait_on_freeing_inode(struct inode *inode);
/*
* Called with the inode lock held.
*/
static struct inode *find_inode(struct super_block *sb,
struct hlist_head *head,
int (*test)(struct inode *, void *),
void *data)
{
struct inode *inode = NULL;
repeat:
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_sb != sb)
continue;
if (!test(inode, data))
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
if (unlikely(inode->i_state & I_CREATING)) {
spin_unlock(&inode->i_lock);
return ERR_PTR(-ESTALE);
}
__iget(inode);
spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
}
/*
* find_inode_fast is the fast path version of find_inode, see the comment at
* iget_locked for details.
*/
static struct inode *find_inode_fast(struct super_block *sb,
struct hlist_head *head, unsigned long ino)
{
struct inode *inode = NULL;
repeat:
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_ino != ino)
continue;
if (inode->i_sb != sb)
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
if (unlikely(inode->i_state & I_CREATING)) {
spin_unlock(&inode->i_lock);
return ERR_PTR(-ESTALE);
}
__iget(inode);
spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
}
/*
* Each cpu owns a range of LAST_INO_BATCH numbers.
* 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
* to renew the exhausted range.
*
* This does not significantly increase overflow rate because every CPU can
* consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
* NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
* 2^32 range, and is a worst-case. Even a 50% wastage would only increase
* overflow rate by 2x, which does not seem too significant.
*
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
* error if st_ino won't fit in target struct field. Use 32bit counter
* here to attempt to avoid that.
*/
#define LAST_INO_BATCH 1024
static DEFINE_PER_CPU(unsigned int, last_ino);
unsigned int get_next_ino(void)
{
unsigned int *p = &get_cpu_var(last_ino);
unsigned int res = *p;
#ifdef CONFIG_SMP
if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
static atomic_t shared_last_ino;
int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
res = next - LAST_INO_BATCH;
}
#endif
res++;
/* get_next_ino should not provide a 0 inode number */
if (unlikely(!res))
res++;
*p = res;
put_cpu_var(last_ino);
return res;
}
EXPORT_SYMBOL(get_next_ino);
/**
* new_inode_pseudo - obtain an inode
* @sb: superblock
*
* Allocates a new inode for given superblock.
* Inode wont be chained in superblock s_inodes list
* This means :
* - fs can't be unmount
* - quotas, fsnotify, writeback can't work
*/
struct inode *new_inode_pseudo(struct super_block *sb)
{
struct inode *inode = alloc_inode(sb);
if (inode) {
spin_lock(&inode->i_lock);
inode->i_state = 0;
spin_unlock(&inode->i_lock);
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(&sb->s_inode_list_lock);
inode = new_inode_pseudo(sb);
if (inode)
inode_sb_list_add(inode);
return inode;
}
EXPORT_SYMBOL(new_inode);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void lockdep_annotate_inode_mutex_key(struct inode *inode)
{
if (S_ISDIR(inode->i_mode)) {
struct file_system_type *type = inode->i_sb->s_type;
/* Set new key only if filesystem hasn't already changed it */
if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) {
/*
* ensure nobody is actually holding i_mutex
*/
// mutex_destroy(&inode->i_mutex);
init_rwsem(&inode->i_rwsem);
lockdep_set_class(&inode->i_rwsem,
&type->i_mutex_dir_key);
}
}
}
EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
#endif
/**
* unlock_new_inode - clear the I_NEW state and wake up any waiters
* @inode: new inode to unlock
*
* Called when the inode is fully initialised to clear the new state of the
* inode and wake up anyone waiting for the inode to finish initialisation.
*/
void unlock_new_inode(struct inode *inode)
{
lockdep_annotate_inode_mutex_key(inode);
spin_lock(&inode->i_lock);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW & ~I_CREATING;
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(unlock_new_inode);
void discard_new_inode(struct inode *inode)
{
lockdep_annotate_inode_mutex_key(inode);
spin_lock(&inode->i_lock);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW;
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
spin_unlock(&inode->i_lock);
iput(inode);
}
EXPORT_SYMBOL(discard_new_inode);
/**
* lock_two_nondirectories - take two i_mutexes on non-directory objects
*
* Lock any non-NULL argument that is not a directory.
* Zero, one or two objects may be locked by this function.
*
* @inode1: first inode to lock
* @inode2: second inode to lock
*/
void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
if (inode1 > inode2)
swap(inode1, inode2);
if (inode1 && !S_ISDIR(inode1->i_mode))
inode_lock(inode1);
if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
inode_lock_nested(inode2, I_MUTEX_NONDIR2);
}
EXPORT_SYMBOL(lock_two_nondirectories);
/**
* unlock_two_nondirectories - release locks from lock_two_nondirectories()
* @inode1: first inode to unlock
* @inode2: second inode to unlock
*/
void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
if (inode1 && !S_ISDIR(inode1->i_mode))
inode_unlock(inode1);
if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
inode_unlock(inode2);
}
EXPORT_SYMBOL(unlock_two_nondirectories);
/**
* inode_insert5 - obtain an inode from a mounted file system
* @inode: pre-allocated inode to use for insert to cache
* @hashval: hash value (usually inode number) to get
* @test: callback used for comparisons between inodes
* @set: callback used to initialize a new struct inode
* @data: opaque data pointer to pass to @test and @set
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if present it is return it with an increased reference count. This is
* a variant of iget5_locked() for callers that don't want to fail on memory
* allocation of inode.
*
* If the inode is not in cache, insert the pre-allocated inode to cache and
* return it locked, hashed, and with the I_NEW flag set. The file system gets
* to fill it in before unlocking it via unlock_new_inode().
*
* Note both @test and @set are called with the inode_hash_lock held, so can't
* sleep.
*/
struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
struct inode *old;
bool creating = inode->i_state & I_CREATING;
again:
spin_lock(&inode_hash_lock);
old = find_inode(inode->i_sb, head, test, data);
if (unlikely(old)) {
/*
* Uhhuh, somebody else created the same inode under us.
* Use the old inode instead of the preallocated one.
*/
spin_unlock(&inode_hash_lock);
if (IS_ERR(old))
return NULL;
wait_on_inode(old);
if (unlikely(inode_unhashed(old))) {
iput(old);
goto again;
}
return old;
}
if (set && unlikely(set(inode, data))) {
inode = NULL;
goto unlock;
}
/*
* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
*/
spin_lock(&inode->i_lock);
inode->i_state |= I_NEW;
hlist_add_head(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
if (!creating)
inode_sb_list_add(inode);
unlock:
spin_unlock(&inode_hash_lock);
return inode;
}
EXPORT_SYMBOL(inode_insert5);
/**
* iget5_locked - obtain an inode from a mounted file system
* @sb: super block of file system
* @hashval: hash value (usually inode number) to get
* @test: callback used for comparisons between inodes
* @set: callback used to initialize a new struct inode
* @data: opaque data pointer to pass to @test and @set
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if present it is return it with an increased reference count. This is
* a generalized version of iget_locked() for file systems where the inode
* number is not sufficient for unique identification of an inode.
*
* If the inode is not in cache, allocate a new inode and return it locked,
* hashed, and with the I_NEW flag set. The file system gets to fill it in
* before unlocking it via unlock_new_inode().
*
* Note both @test and @set are called with the inode_hash_lock held, so can't
* sleep.
*/
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
struct inode *inode = ilookup5(sb, hashval, test, data);
if (!inode) {
struct inode *new = alloc_inode(sb);
if (new) {
new->i_state = 0;
inode = inode_insert5(new, hashval, test, set, data);
if (unlikely(inode != new))
destroy_inode(new);
}
}
return inode;
}
EXPORT_SYMBOL(iget5_locked);
/**
* iget_locked - obtain an inode from a mounted file system
* @sb: super block of file system
* @ino: inode number to get
*
* Search for the inode specified by @ino in the inode cache and if present
* return it with an increased reference count. This is for file systems
* where the inode number is sufficient for unique identification of an inode.
*
* If the inode is not in cache, allocate a new inode and return it locked,
* hashed, and with the I_NEW flag set. The file system gets to fill it in
* before unlocking it via unlock_new_inode().
*/
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
again:
spin_lock(&inode_hash_lock);
inode = find_inode_fast(sb, head, ino);
spin_unlock(&inode_hash_lock);
if (inode) {
if (IS_ERR(inode))
return NULL;
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
return inode;
}
inode = alloc_inode(sb);
if (inode) {
struct inode *old;
spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode_fast(sb, head, ino);
if (!old) {
inode->i_ino = ino;
spin_lock(&inode->i_lock);
inode->i_state = I_NEW;
hlist_add_head(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
inode_sb_list_add(inode);
spin_unlock(&inode_hash_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
*/
return inode;
}
/*
* Uhhuh, somebody else created the same inode under
* us. Use the old inode instead of the one we just
* allocated.
*/
spin_unlock(&inode_hash_lock);
destroy_inode(inode);
if (IS_ERR(old))
return NULL;
inode = old;
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
}
return inode;
}
EXPORT_SYMBOL(iget_locked);
/*
* search the inode cache for a matching inode number.
* If we find one, then the inode number we are trying to
* allocate is not unique and so we should not use it.
*
* Returns 1 if the inode number is unique, 0 if it is not.
*/
static int test_inode_iunique(struct super_block *sb, unsigned long ino)
{
struct hlist_head *b = inode_hashtable + hash(sb, ino);
struct inode *inode;
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 IS_ERR(inode) ? NULL : inode;
}
EXPORT_SYMBOL(ilookup5_nowait);
/**
* ilookup5 - search for an inode in the inode cache
* @sb: super block of file system to search
* @hashval: hash value (usually inode number) to search for
* @test: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @test
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if the inode is in the cache, return the inode with an incremented
* reference count. Waits on I_NEW before returning the inode.
* returned with an incremented reference count.
*
* This is a generalized version of ilookup() for file systems where the
* inode number is not sufficient for unique identification of an inode.
*
* Note: @test is called with the inode_hash_lock held, so can't sleep.
*/
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct inode *inode;
again:
inode = ilookup5_nowait(sb, hashval, test, data);
if (inode) {
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
}
return inode;
}
EXPORT_SYMBOL(ilookup5);
/**
* ilookup - search for an inode in the inode cache
* @sb: super block of file system to search
* @ino: inode number to search for
*
* Search for the inode @ino in the inode cache, and if the inode is in the
* cache, the inode is returned with an incremented reference count.
*/
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
again:
spin_lock(&inode_hash_lock);
inode = find_inode_fast(sb, head, ino);
spin_unlock(&inode_hash_lock);
if (inode) {
if (IS_ERR(inode))
return NULL;
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
}
return inode;
}
EXPORT_SYMBOL(ilookup);
/**
* find_inode_nowait - find an inode in the inode cache
* @sb: super block of file system to search
* @hashval: hash value (usually inode number) to search for
* @match: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @match
*
* Search for the inode specified by @hashval and @data in the inode
* cache, where the helper function @match will return 0 if the inode
* does not match, 1 if the inode does match, and -1 if the search
* should be stopped. The @match function must be responsible for
* taking the i_lock spin_lock and checking i_state for an inode being
* freed or being initialized, and incrementing the reference count
* before returning 1. It also must not sleep, since it is called with
* the inode_hash_lock spinlock held.
*
* This is a even more generalized version of ilookup5() when the
* function must never block --- find_inode() can block in
* __wait_on_freeing_inode() --- or when the caller can not increment
* the reference count because the resulting iput() might cause an
* inode eviction. The tradeoff is that the @match funtion must be
* very carefully implemented.
*/
struct inode *find_inode_nowait(struct super_block *sb,
unsigned long hashval,
int (*match)(struct inode *, unsigned long,
void *),
void *data)
{
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
struct inode *inode, *ret_inode = NULL;
int mval;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_sb != sb)
continue;
mval = match(inode, hashval, data);
if (mval == 0)
continue;
if (mval == 1)
ret_inode = inode;
goto out;
}
out:
spin_unlock(&inode_hash_lock);
return ret_inode;
}
EXPORT_SYMBOL(find_inode_nowait);
int insert_inode_locked(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
struct hlist_head *head = inode_hashtable + hash(sb, ino);
while (1) {
struct inode *old = NULL;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, head, i_hash) {
if (old->i_ino != ino)
continue;
if (old->i_sb != sb)
continue;
spin_lock(&old->i_lock);
if (old->i_state & (I_FREEING|I_WILL_FREE)) {
spin_unlock(&old->i_lock);
continue;
}
break;
}
if (likely(!old)) {
spin_lock(&inode->i_lock);
inode->i_state |= I_NEW | I_CREATING;
hlist_add_head(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
return 0;
}
if (unlikely(old->i_state & I_CREATING)) {
spin_unlock(&old->i_lock);
spin_unlock(&inode_hash_lock);
return -EBUSY;
}
__iget(old);
spin_unlock(&old->i_lock);
spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
return -EBUSY;
}
iput(old);
}
}
EXPORT_SYMBOL(insert_inode_locked);
int insert_inode_locked4(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct inode *old;
inode->i_state |= I_CREATING;
old = inode_insert5(inode, hashval, test, NULL, data);
if (old != inode) {
iput(old);
return -EBUSY;
}
return 0;
}
EXPORT_SYMBOL(insert_inode_locked4);
int generic_delete_inode(struct inode *inode)
{
return 1;
}
EXPORT_SYMBOL(generic_delete_inode);
/*
* Called when we're dropping the last reference
* to an inode.
*
* Call the FS "drop_inode()" function, defaulting to
* the legacy UNIX filesystem behaviour. If it tells
* us to evict inode, do so. Otherwise, retain inode
* in cache if fs is alive, sync and evict if fs is
* shutting down.
*/
static void iput_final(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
const struct super_operations *op = inode->i_sb->s_op;
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 & SB_ACTIVE)) {
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)
return;
BUG_ON(inode->i_state & I_CLEAR);
retry:
if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) {
if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) {
atomic_inc(&inode->i_count);
spin_unlock(&inode->i_lock);
trace_writeback_lazytime_iput(inode);
mark_inode_dirty_sync(inode);
goto retry;
}
iput_final(inode);
}
}
EXPORT_SYMBOL(iput);
/**
* 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 (timespec64_compare(&inode->i_mtime, &inode->i_atime) >= 0)
return 1;
/*
* Is ctime younger than atime? If yes, update atime:
*/
if (timespec64_compare(&inode->i_ctime, &inode->i_atime) >= 0)
return 1;
/*
* Is the previous atime value older than a day? If yes,
* update atime:
*/
if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
return 1;
/*
* Good, we can skip the atime update:
*/
return 0;
}
int generic_update_time(struct inode *inode, struct timespec64 *time, int flags)
{
int iflags = I_DIRTY_TIME;
bool dirty = false;
if (flags & S_ATIME)
inode->i_atime = *time;
if (flags & S_VERSION)
dirty = inode_maybe_inc_iversion(inode, false);
if (flags & S_CTIME)
inode->i_ctime = *time;
if (flags & S_MTIME)
inode->i_mtime = *time;
if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
!(inode->i_sb->s_flags & SB_LAZYTIME))
dirty = true;
if (dirty)
iflags |= I_DIRTY_SYNC;
__mark_inode_dirty(inode, iflags);
return 0;
}
EXPORT_SYMBOL(generic_update_time);
/*
* This does the actual work of updating an inodes time or version. Must have
* had called mnt_want_write() before calling this.
*/
static int update_time(struct inode *inode, struct timespec64 *time, int flags)
{
int (*update_time)(struct inode *, struct timespec64 *, int);
update_time = inode->i_op->update_time ? inode->i_op->update_time :
generic_update_time;
return update_time(inode, time, flags);
}
/**
* touch_atime - update the access time
* @path: the &struct path to update
* @inode: inode to update
*
* Update the accessed time on an inode and mark it for writeback.
* This function automatically handles read only file systems and media,
* as well as the "noatime" flag and inode specific "noatime" markers.
*/
bool atime_needs_update(const struct path *path, struct inode *inode)
{
struct vfsmount *mnt = path->mnt;
struct timespec64 now;
if (inode->i_flags & S_NOATIME)
return false;
/* Atime updates will likely cause i_uid and i_gid to be written
* back improprely if their true value is unknown to the vfs.
*/
if (HAS_UNMAPPED_ID(inode))
return false;
if (IS_NOATIME(inode))
return false;
if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode))
return false;
if (mnt->mnt_flags & MNT_NOATIME)
return false;
if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
return false;
now = current_time(inode);
if (!relatime_need_update(mnt, inode, timespec64_to_timespec(now)))
return false;
if (timespec64_equal(&inode->i_atime, &now))
return false;
return true;
}
void touch_atime(const struct path *path)
{
struct vfsmount *mnt = path->mnt;
struct inode *inode = d_inode(path->dentry);
struct timespec64 now;
if (!atime_needs_update(path, inode))
return;
if (!sb_start_write_trylock(inode->i_sb))
return;
if (__mnt_want_write(mnt) != 0)
goto skip_update;
/*
* File systems can error out when updating inodes if they need to
* allocate new space to modify an inode (such is the case for
* Btrfs), but since we touch atime while walking down the path we
* really don't care if we failed to update the atime of the file,
* so just ignore the return value.
* We may also fail on filesystems that have the ability to make parts
* of the fs read only, e.g. subvolumes in Btrfs.
*/
now = current_time(inode);
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 = d_inode(dentry)->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);
/*
* Return mask of changes for notify_change() that need to be done as a
* response to write or truncate. Return 0 if nothing has to be changed.
* Negative value on error (change should be denied).
*/
int dentry_needs_remove_privs(struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
int mask = 0;
int ret;
if (IS_NOSEC(inode))
return 0;
mask = should_remove_suid(dentry);
ret = security_inode_need_killpriv(dentry);
if (ret < 0)
return ret;
if (ret)
mask |= ATTR_KILL_PRIV;
return mask;
}
static int __remove_privs(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);
}
/*
* Remove special file priviledges (suid, capabilities) when file is written
* to or truncated.
*/
int file_remove_privs(struct file *file)
{
struct dentry *dentry = file_dentry(file);
struct inode *inode = file_inode(file);
int kill;
int error = 0;
/* Fast path for nothing security related */
if (IS_NOSEC(inode))
return 0;
kill = dentry_needs_remove_privs(dentry);
if (kill < 0)
return kill;
if (kill)
error = __remove_privs(dentry, kill);
if (!error)
inode_has_no_xattr(inode);
return error;
}
EXPORT_SYMBOL(file_remove_privs);
/**
* 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 timespec64 now;
int sync_it = 0;
int ret;
/* First try to exhaust all avenues to not sync */
if (IS_NOCMTIME(inode))
return 0;
now = current_time(inode);
if (!timespec64_equal(&inode->i_mtime, &now))
sync_it = S_MTIME;
if (!timespec64_equal(&inode->i_ctime, &now))
sync_it |= S_CTIME;
if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
sync_it |= S_VERSION;
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);
/*
* If we try to find an inode in the inode hash while it is being
* deleted, we have to wait until the filesystem completes its
* deletion before reporting that it isn't found. This function waits
* until the deletion _might_ have completed. Callers are responsible
* to recheck inode state.
*
* It doesn't matter if I_NEW is not set initially, a call to
* wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
* will DTRT.
*/
static void __wait_on_freeing_inode(struct inode *inode)
{
wait_queue_head_t *wq;
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
schedule();
finish_wait(wq, &wait.wq_entry);
spin_lock(&inode_hash_lock);
}
static __initdata unsigned long ihash_entries;
static int __init set_ihash_entries(char *str)
{
if (!str)
return 0;
ihash_entries = simple_strtoul(str, &str, 0);
return 1;
}
__setup("ihash_entries=", set_ihash_entries);
/*
* Initialize the waitqueues and inode hash table.
*/
void __init inode_init_early(void)
{
/* If hashes are distributed across NUMA nodes, defer
* hash allocation until vmalloc space is available.
*/
if (hashdist)
return;
inode_hashtable =
alloc_large_system_hash("Inode-cache",
sizeof(struct hlist_head),
ihash_entries,
14,
HASH_EARLY | HASH_ZERO,
&i_hash_shift,
&i_hash_mask,
0,
0);
}
void __init inode_init(void)
{
/* inode slab cache */
inode_cachep = kmem_cache_create("inode_cache",
sizeof(struct inode),
0,
(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
init_once);
/* Hash may have been set up in inode_init_early */
if (!hashdist)
return;
inode_hashtable =
alloc_large_system_hash("Inode-cache",
sizeof(struct hlist_head),
ihash_entries,
14,
HASH_ZERO,
&i_hash_shift,
&i_hash_mask,
0,
0);
}
void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
{
inode->i_mode = mode;
if (S_ISCHR(mode)) {
inode->i_fop = &def_chr_fops;
inode->i_rdev = rdev;
} else if (S_ISBLK(mode)) {
inode->i_fop = &def_blk_fops;
inode->i_rdev = rdev;
} else if (S_ISFIFO(mode))
inode->i_fop = &pipefifo_fops;
else if (S_ISSOCK(mode))
; /* leave it no_open_fops */
else
printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
" inode %s:%lu\n", mode, inode->i_sb->s_id,
inode->i_ino);
}
EXPORT_SYMBOL(init_special_inode);
/**
* inode_init_owner - Init uid,gid,mode for new inode according to posix standards
* @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;
/* Directories are special, and always inherit S_ISGID */
if (S_ISDIR(mode))
mode |= S_ISGID;
else if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP) &&
!in_group_p(inode->i_gid) &&
!capable_wrt_inode_uidgid(dir, CAP_FSETID))
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 in a namespace with the
* inode owner uid mapped, or owns the file.
*/
bool inode_owner_or_capable(const struct inode *inode)
{
struct user_namespace *ns;
if (uid_eq(current_fsuid(), inode->i_uid))
return true;
ns = current_user_ns();
if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER))
return true;
return false;
}
EXPORT_SYMBOL(inode_owner_or_capable);
/*
* Direct i/o helper functions
*/
static void __inode_dio_wait(struct inode *inode)
{
wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
do {
prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE);
if (atomic_read(&inode->i_dio_count))
schedule();
} while (atomic_read(&inode->i_dio_count));
finish_wait(wq, &q.wq_entry);
}
/**
* inode_dio_wait - wait for outstanding DIO requests to finish
* @inode: inode to wait for
*
* Waits for all pending direct I/O requests to finish so that we can
* proceed with a truncate or equivalent operation.
*
* Must be called under a lock that serializes taking new references
* to i_dio_count, usually by inode->i_mutex.
*/
void inode_dio_wait(struct inode *inode)
{
if (atomic_read(&inode->i_dio_count))
__inode_dio_wait(inode);
}
EXPORT_SYMBOL(inode_dio_wait);
/*
* inode_set_flags - atomically set some inode flags
*
* Note: the caller should be holding i_mutex, or else be sure that
* they have exclusive access to the inode structure (i.e., while the
* inode is being instantiated). The reason for the cmpxchg() loop
* --- which wouldn't be necessary if all code paths which modify
* i_flags actually followed this rule, is that there is at least one
* code path which doesn't today so we use cmpxchg() out of an abundance
* of caution.
*
* In the long run, i_mutex is overkill, and we should probably look
* at using the i_lock spinlock to protect i_flags, and then make sure
* it is so documented in include/linux/fs.h and that all code follows
* the locking convention!!
*/
void inode_set_flags(struct inode *inode, unsigned int flags,
unsigned int mask)
{
unsigned int old_flags, new_flags;
WARN_ON_ONCE(flags & ~mask);
do {
old_flags = READ_ONCE(inode->i_flags);
new_flags = (old_flags & ~mask) | flags;
} while (unlikely(cmpxchg(&inode->i_flags, old_flags,
new_flags) != old_flags));
}
EXPORT_SYMBOL(inode_set_flags);
void inode_nohighmem(struct inode *inode)
{
mapping_set_gfp_mask(inode->i_mapping, GFP_USER);
}
EXPORT_SYMBOL(inode_nohighmem);
/**
* timespec64_trunc - Truncate timespec64 to a granularity
* @t: Timespec64
* @gran: Granularity in ns.
*
* Truncate a timespec64 to a granularity. Always rounds down. gran must
* not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
*/
struct timespec64 timespec64_trunc(struct timespec64 t, unsigned gran)
{
/* Avoid division in the common cases 1 ns and 1 s. */
if (gran == 1) {
/* nothing */
} else if (gran == NSEC_PER_SEC) {
t.tv_nsec = 0;
} else if (gran > 1 && gran < NSEC_PER_SEC) {
t.tv_nsec -= t.tv_nsec % gran;
} else {
WARN(1, "illegal file time granularity: %u", gran);
}
return t;
}
EXPORT_SYMBOL(timespec64_trunc);
/**
* current_time - Return FS time
* @inode: inode.
*
* Return the current time truncated to the time granularity supported by
* the fs.
*
* Note that inode and inode->sb cannot be NULL.
* Otherwise, the function warns and returns time without truncation.
*/
struct timespec64 current_time(struct inode *inode)
{
struct timespec64 now;
ktime_get_coarse_real_ts64(&now);
if (unlikely(!inode->i_sb)) {
WARN(1, "current_time() called with uninitialized super_block in the inode");
return now;
}
return timespec64_trunc(now, inode->i_sb->s_time_gran);
}
EXPORT_SYMBOL(current_time);