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/*
* linux/fs/inode.c
*
* (C) 1997 Linus Torvalds
*/
#include <linux/config.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/dcache.h>
#include <linux/init.h>
#include <linux/quotaops.h>
#include <linux/slab.h>
#include <linux/cache.h>
#include <linux/swap.h>
#include <linux/swapctl.h>
#include <linux/prefetch.h>
#include <linux/locks.h>
/*
* New inode.c implementation.
*
* This implementation has the basic premise of trying
* to be extremely low-overhead and SMP-safe, yet be
* simple enough to be "obviously correct".
*
* Famous last words.
*/
/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
/* #define INODE_PARANOIA 1 */
/* #define INODE_DEBUG 1 */
/*
* Inode lookup is no longer as critical as it used to be:
* most of the lookups are going to be through the dcache.
*/
#define I_HASHBITS i_hash_shift
#define I_HASHMASK i_hash_mask
static unsigned int i_hash_mask;
static unsigned int i_hash_shift;
/*
* Each inode can be on two separate lists. One is
* the hash list of the inode, used for lookups. The
* other linked list is the "type" list:
* "in_use" - valid inode, i_count > 0, i_nlink > 0
* "dirty" - as "in_use" but also dirty
* "unused" - valid inode, i_count = 0
*
* A "dirty" list is maintained for each super block,
* allowing for low-overhead inode sync() operations.
*/
static LIST_HEAD(inode_in_use);
static LIST_HEAD(inode_unused);
static struct list_head *inode_hashtable;
static LIST_HEAD(anon_hash_chain); /* for inodes with NULL i_sb */
/*
* A simple spinlock to protect the list manipulations.
*
* NOTE! You also have to own the lock if you change
* the i_state of an inode while it is in use..
*/
static spinlock_t inode_lock = SPIN_LOCK_UNLOCKED;
/*
* Statistics gathering..
*/
struct inodes_stat_t inodes_stat;
static kmem_cache_t * inode_cachep;
#define alloc_inode(gfp_mask) \
((struct inode *) kmem_cache_alloc(inode_cachep, gfp_mask))
static void destroy_inode(struct inode *inode)
{
if (inode_has_buffers(inode))
BUG();
kmem_cache_free(inode_cachep, (inode));
}
/*
* These are initializations that only need to be done
* once, because the fields are idempotent across use
* of the inode, so let the slab aware of that.
*/
static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
struct inode * inode = (struct inode *) foo;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR)
{
memset(inode, 0, sizeof(*inode));
init_waitqueue_head(&inode->i_wait);
INIT_LIST_HEAD(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_data.clean_pages);
INIT_LIST_HEAD(&inode->i_data.dirty_pages);
INIT_LIST_HEAD(&inode->i_data.locked_pages);
INIT_LIST_HEAD(&inode->i_dentry);
INIT_LIST_HEAD(&inode->i_dirty_buffers);
INIT_LIST_HEAD(&inode->i_dirty_data_buffers);
INIT_LIST_HEAD(&inode->i_devices);
sema_init(&inode->i_sem, 1);
sema_init(&inode->i_zombie, 1);
spin_lock_init(&inode->i_data.i_shared_lock);
}
}
/*
* Put the inode on the super block's dirty list.
*
* CAREFUL! We mark it dirty unconditionally, but
* move it onto the dirty list only if it is hashed.
* If it was not hashed, it will never be added to
* the dirty list even if it is later hashed, as it
* will have been marked dirty already.
*
* In short, make sure you hash any inodes _before_
* you start marking them dirty..
*/
/**
* __mark_inode_dirty - internal function
* @inode: inode to mark
* @flags: what kind of dirty (i.e. I_DIRTY_SYNC)
* Mark an inode as dirty. Callers should use mark_inode_dirty or
* mark_inode_dirty_sync.
*/
void __mark_inode_dirty(struct inode *inode, int flags)
{
struct super_block * sb = inode->i_sb;
if (!sb)
return;
/* Don't do this for I_DIRTY_PAGES - that doesn't actually dirty the inode itself */
if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
if (sb->s_op && sb->s_op->dirty_inode)
sb->s_op->dirty_inode(inode);
}
/* avoid the locking if we can */
if ((inode->i_state & flags) == flags)
return;
spin_lock(&inode_lock);
if ((inode->i_state & flags) != flags) {
inode->i_state |= flags;
/* Only add valid (ie hashed) inodes to the dirty list */
if (!(inode->i_state & I_LOCK) && !list_empty(&inode->i_hash)) {
list_del(&inode->i_list);
list_add(&inode->i_list, &sb->s_dirty);
}
}
spin_unlock(&inode_lock);
}
static void __wait_on_inode(struct inode * inode)
{
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(&inode->i_wait, &wait);
repeat:
set_current_state(TASK_UNINTERRUPTIBLE);
if (inode->i_state & I_LOCK) {
schedule();
goto repeat;
}
remove_wait_queue(&inode->i_wait, &wait);
current->state = TASK_RUNNING;
}
static inline void wait_on_inode(struct inode *inode)
{
if (inode->i_state & I_LOCK)
__wait_on_inode(inode);
}
static inline void write_inode(struct inode *inode, int sync)
{
if (inode->i_sb && inode->i_sb->s_op && inode->i_sb->s_op->write_inode && !is_bad_inode(inode))
inode->i_sb->s_op->write_inode(inode, sync);
}
static inline void __iget(struct inode * inode)
{
if (atomic_read(&inode->i_count)) {
atomic_inc(&inode->i_count);
return;
}
atomic_inc(&inode->i_count);
if (!(inode->i_state & (I_DIRTY|I_LOCK))) {
list_del(&inode->i_list);
list_add(&inode->i_list, &inode_in_use);
}
inodes_stat.nr_unused--;
}
static inline void __sync_one(struct inode *inode, int sync)
{
unsigned dirty;
list_del(&inode->i_list);
list_add(&inode->i_list, &inode->i_sb->s_locked_inodes);
if (inode->i_state & I_LOCK)
BUG();
/* Set I_LOCK, reset I_DIRTY */
dirty = inode->i_state & I_DIRTY;
inode->i_state |= I_LOCK;
inode->i_state &= ~I_DIRTY;
spin_unlock(&inode_lock);
filemap_fdatasync(inode->i_mapping);
/* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC))
write_inode(inode, sync);
filemap_fdatawait(inode->i_mapping);
spin_lock(&inode_lock);
inode->i_state &= ~I_LOCK;
if (!(inode->i_state & I_FREEING)) {
struct list_head *to;
if (inode->i_state & I_DIRTY)
to = &inode->i_sb->s_dirty;
else if (atomic_read(&inode->i_count))
to = &inode_in_use;
else
to = &inode_unused;
list_del(&inode->i_list);
list_add(&inode->i_list, to);
}
wake_up(&inode->i_wait);
}
static inline void sync_one(struct inode *inode, int sync)
{
if (inode->i_state & I_LOCK) {
__iget(inode);
spin_unlock(&inode_lock);
__wait_on_inode(inode);
iput(inode);
spin_lock(&inode_lock);
} else {
__sync_one(inode, sync);
}
}
static inline void sync_list(struct list_head *head)
{
struct list_head * tmp;
while ((tmp = head->prev) != head)
__sync_one(list_entry(tmp, struct inode, i_list), 0);
}
static inline void wait_on_locked(struct list_head *head)
{
struct list_head * tmp;
while ((tmp = head->prev) != head) {
struct inode *inode = list_entry(tmp, struct inode, i_list);
__iget(inode);
spin_unlock(&inode_lock);
__wait_on_inode(inode);
iput(inode);
spin_lock(&inode_lock);
}
}
static inline int try_to_sync_unused_list(struct list_head *head, int nr_inodes)
{
struct list_head *tmp = head;
struct inode *inode;
while (nr_inodes && (tmp = tmp->prev) != head) {
inode = list_entry(tmp, struct inode, i_list);
if (!atomic_read(&inode->i_count)) {
__sync_one(inode, 0);
nr_inodes--;
/*
* __sync_one moved the inode to another list,
* so we have to start looking from the list head.
*/
tmp = head;
}
}
return nr_inodes;
}
void sync_inodes_sb(struct super_block *sb)
{
spin_lock(&inode_lock);
while (!list_empty(&sb->s_dirty)||!list_empty(&sb->s_locked_inodes)) {
sync_list(&sb->s_dirty);
wait_on_locked(&sb->s_locked_inodes);
}
spin_unlock(&inode_lock);
}
/*
* Note:
* We don't need to grab a reference to superblock here. If it has non-empty
* ->s_dirty it's hadn't been killed yet and kill_super() won't proceed
* past sync_inodes_sb() until both ->s_dirty and ->s_locked_inodes are
* empty. Since __sync_one() regains inode_lock before it finally moves
* inode from superblock lists we are OK.
*/
void sync_unlocked_inodes(void)
{
struct super_block * sb;
spin_lock(&inode_lock);
spin_lock(&sb_lock);
sb = sb_entry(super_blocks.next);
for (; sb != sb_entry(&super_blocks); sb = sb_entry(sb->s_list.next)) {
if (!list_empty(&sb->s_dirty)) {
spin_unlock(&sb_lock);
sync_list(&sb->s_dirty);
spin_lock(&sb_lock);
}
}
spin_unlock(&sb_lock);
spin_unlock(&inode_lock);
}
/*
* Find a superblock with inodes that need to be synced
*/
static struct super_block *get_super_to_sync(void)
{
struct list_head *p;
restart:
spin_lock(&inode_lock);
spin_lock(&sb_lock);
list_for_each(p, &super_blocks) {
struct super_block *s = list_entry(p,struct super_block,s_list);
if (list_empty(&s->s_dirty) && list_empty(&s->s_locked_inodes))
continue;
s->s_count++;
spin_unlock(&sb_lock);
spin_unlock(&inode_lock);
down_read(&s->s_umount);
if (!s->s_root) {
drop_super(s);
goto restart;
}
return s;
}
spin_unlock(&sb_lock);
spin_unlock(&inode_lock);
return NULL;
}
/**
* sync_inodes
* @dev: device to sync the inodes from.
*
* sync_inodes goes through the super block's dirty list,
* writes them out, and puts them back on the normal list.
*/
void sync_inodes(kdev_t dev)
{
struct super_block * s;
/*
* Search the super_blocks array for the device(s) to sync.
*/
if (dev) {
if ((s = get_super(dev)) != NULL) {
sync_inodes_sb(s);
drop_super(s);
}
} else {
while ((s = get_super_to_sync()) != NULL) {
sync_inodes_sb(s);
drop_super(s);
}
}
}
static void try_to_sync_unused_inodes(void * arg)
{
struct super_block * sb;
int nr_inodes = inodes_stat.nr_unused;
spin_lock(&inode_lock);
spin_lock(&sb_lock);
sb = sb_entry(super_blocks.next);
for (; nr_inodes && sb != sb_entry(&super_blocks); sb = sb_entry(sb->s_list.next)) {
if (list_empty(&sb->s_dirty))
continue;
spin_unlock(&sb_lock);
nr_inodes = try_to_sync_unused_list(&sb->s_dirty, nr_inodes);
spin_lock(&sb_lock);
}
spin_unlock(&sb_lock);
spin_unlock(&inode_lock);
}
static struct tq_struct unused_inodes_flush_task;
/**
* write_inode_now - write an inode to disk
* @inode: inode to write to disk
* @sync: whether the write should be synchronous or not
*
* This function commits an inode to disk immediately if it is
* dirty. This is primarily needed by knfsd.
*/
void write_inode_now(struct inode *inode, int sync)
{
struct super_block * sb = inode->i_sb;
if (sb) {
spin_lock(&inode_lock);
while (inode->i_state & I_DIRTY)
sync_one(inode, sync);
spin_unlock(&inode_lock);
if (sync)
wait_on_inode(inode);
}
else
printk(KERN_ERR "write_inode_now: no super block\n");
}
/**
* generic_osync_inode - flush all dirty data for a given inode to disk
* @inode: inode to write
* @datasync: if set, don't bother flushing timestamps
*
* This can be called by file_write functions for files which have the
* O_SYNC flag set, to flush dirty writes to disk.
*/
int generic_osync_inode(struct inode *inode, int what)
{
int err = 0, err2 = 0, need_write_inode_now = 0;
/*
* WARNING
*
* Currently, the filesystem write path does not pass the
* filp down to the low-level write functions. Therefore it
* is impossible for (say) __block_commit_write to know if
* the operation is O_SYNC or not.
*
* Ideally, O_SYNC writes would have the filesystem call
* ll_rw_block as it went to kick-start the writes, and we
* could call osync_inode_buffers() here to wait only for
* those IOs which have already been submitted to the device
* driver layer. As it stands, if we did this we'd not write
* anything to disk since our writes have not been queued by
* this point: they are still on the dirty LRU.
*
* So, currently we will call fsync_inode_buffers() instead,
* to flush _all_ dirty buffers for this inode to disk on
* every O_SYNC write, not just the synchronous I/Os. --sct
*/
if (what & OSYNC_METADATA)
err = fsync_inode_buffers(inode);
if (what & OSYNC_DATA)
err2 = fsync_inode_data_buffers(inode);
if (!err)
err = err2;
spin_lock(&inode_lock);
if ((inode->i_state & I_DIRTY) &&
((what & OSYNC_INODE) || (inode->i_state & I_DIRTY_DATASYNC)))
need_write_inode_now = 1;
spin_unlock(&inode_lock);
if (need_write_inode_now)
write_inode_now(inode, 1);
else
wait_on_inode(inode);
return err;
}
/**
* clear_inode - clear an inode
* @inode: inode to clear
*
* This is called by the filesystem to tell us
* that the inode is no longer useful. We just
* terminate it with extreme prejudice.
*/
void clear_inode(struct inode *inode)
{
invalidate_inode_buffers(inode);
if (inode->i_data.nrpages)
BUG();
if (!(inode->i_state & I_FREEING))
BUG();
if (inode->i_state & I_CLEAR)
BUG();
wait_on_inode(inode);
DQUOT_DROP(inode);
if (inode->i_sb && inode->i_sb->s_op && inode->i_sb->s_op->clear_inode)
inode->i_sb->s_op->clear_inode(inode);
if (inode->i_bdev)
bd_forget(inode);
else if (inode->i_cdev) {
cdput(inode->i_cdev);
inode->i_cdev = NULL;
}
inode->i_state = I_CLEAR;
}
/*
* 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)
{
struct list_head * inode_entry;
struct inode * inode;
while ((inode_entry = head->next) != head)
{
list_del(inode_entry);
inode = list_entry(inode_entry, struct inode, i_list);
if (inode->i_data.nrpages)
truncate_inode_pages(&inode->i_data, 0);
clear_inode(inode);
destroy_inode(inode);
inodes_stat.nr_inodes--;
}
}
/*
* Invalidate all inodes for a device.
*/
static int invalidate_list(struct list_head *head, struct super_block * sb, struct list_head * dispose)
{
struct list_head *next;
int busy = 0, count = 0;
next = head->next;
for (;;) {
struct list_head * tmp = next;
struct inode * inode;
next = next->next;
if (tmp == head)
break;
inode = list_entry(tmp, struct inode, i_list);
if (inode->i_sb != sb)
continue;
invalidate_inode_buffers(inode);
if (!atomic_read(&inode->i_count)) {
list_del_init(&inode->i_hash);
list_del(&inode->i_list);
list_add(&inode->i_list, dispose);
inode->i_state |= I_FREEING;
count++;
continue;
}
busy = 1;
}
/* only unused inodes may be cached with i_count zero */
inodes_stat.nr_unused -= count;
return busy;
}
/*
* This is a two-stage process. First we collect all
* offending inodes onto the throw-away list, and in
* the second stage we actually dispose of them. This
* is because we don't want to sleep while messing
* with the global lists..
*/
/**
* invalidate_inodes - discard the inodes on a device
* @sb: superblock
*
* Discard all of the inodes for a given superblock. If the discard
* fails because there are busy inodes then a non zero value is returned.
* If the discard is successful all the inodes have been discarded.
*/
int invalidate_inodes(struct super_block * sb)
{
int busy;
LIST_HEAD(throw_away);
spin_lock(&inode_lock);
busy = invalidate_list(&inode_in_use, sb, &throw_away);
busy |= invalidate_list(&inode_unused, sb, &throw_away);
busy |= invalidate_list(&sb->s_dirty, sb, &throw_away);
busy |= invalidate_list(&sb->s_locked_inodes, sb, &throw_away);
spin_unlock(&inode_lock);
dispose_list(&throw_away);
return busy;
}
int invalidate_device(kdev_t dev, int do_sync)
{
struct super_block *sb;
int res;
if (do_sync)
fsync_dev(dev);
res = 0;
sb = get_super(dev);
if (sb) {
/*
* no need to lock the super, get_super holds the
* read semaphore so the filesystem cannot go away
* under us (->put_super runs with the write lock
* hold).
*/
shrink_dcache_sb(sb);
res = invalidate_inodes(sb);
drop_super(sb);
}
invalidate_buffers(dev);
return res;
}
/*
* This is called with the inode lock held. It searches
* the in-use for freeable inodes, which are moved to a
* temporary list and then placed on the unused list by
* dispose_list.
*
* We don't expect to have to call this very often.
*
* N.B. The spinlock is released during the call to
* dispose_list.
*/
#define CAN_UNUSE(inode) \
((((inode)->i_state | (inode)->i_data.nrpages) == 0) && \
!inode_has_buffers(inode))
#define INODE(entry) (list_entry(entry, struct inode, i_list))
void prune_icache(int goal)
{
LIST_HEAD(list);
struct list_head *entry, *freeable = &list;
int count;
struct inode * inode;
spin_lock(&inode_lock);
count = 0;
entry = inode_unused.prev;
while (entry != &inode_unused)
{
struct list_head *tmp = entry;
entry = entry->prev;
inode = INODE(tmp);
if (inode->i_state & (I_FREEING|I_CLEAR|I_LOCK))
continue;
if (!CAN_UNUSE(inode))
continue;
if (atomic_read(&inode->i_count))
continue;
list_del(tmp);
list_del(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_hash);
list_add(tmp, freeable);
inode->i_state |= I_FREEING;
count++;
if (!--goal)
break;
}
inodes_stat.nr_unused -= count;
spin_unlock(&inode_lock);
dispose_list(freeable);
/*
* If we didn't freed enough clean inodes schedule
* a sync of the dirty inodes, we cannot do it
* from here or we're either synchronously dogslow
* or we deadlock with oom.
*/
if (goal)
schedule_task(&unused_inodes_flush_task);
}
int shrink_icache_memory(int priority, int gfp_mask)
{
int count = 0;
/*
* Nasty deadlock avoidance..
*
* We may hold various FS locks, and we don't
* want to recurse into the FS that called us
* in clear_inode() and friends..
*/
if (!(gfp_mask & __GFP_FS))
return 0;
count = inodes_stat.nr_unused / priority;
prune_icache(count);
kmem_cache_shrink(inode_cachep);
return 0;
}
/*
* Called with the inode lock held.
* NOTE: we are not increasing the inode-refcount, you must call __iget()
* by hand after calling find_inode now! This simplifies iunique and won't
* add any additional branch in the common code.
*/
static struct inode * find_inode(struct super_block * sb, unsigned long ino, struct list_head *head, find_inode_t find_actor, void *opaque)
{
struct list_head *tmp;
struct inode * inode;
tmp = head;
for (;;) {
tmp = tmp->next;
inode = NULL;
if (tmp == head)
break;
inode = list_entry(tmp, struct inode, i_hash);
if (inode->i_ino != ino)
continue;
if (inode->i_sb != sb)
continue;
if (find_actor && !find_actor(inode, ino, opaque))
continue;
break;
}
return inode;
}
/*
* This just initializes the inode fields
* to known values before returning the inode..
*
* i_sb, i_ino, i_count, i_state and the lists have
* been initialized elsewhere..
*/
static void clean_inode(struct inode *inode)
{
static struct address_space_operations empty_aops;
static struct inode_operations empty_iops;
static struct file_operations empty_fops;
memset(&inode->u, 0, sizeof(inode->u));
inode->i_sock = 0;
inode->i_op = &empty_iops;
inode->i_fop = &empty_fops;
inode->i_nlink = 1;
atomic_set(&inode->i_writecount, 0);
inode->i_size = 0;
inode->i_blocks = 0;
inode->i_bytes = 0;
inode->i_generation = 0;
memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
inode->i_pipe = NULL;
inode->i_bdev = NULL;
inode->i_cdev = NULL;
inode->i_data.a_ops = &empty_aops;
inode->i_data.host = inode;
inode->i_data.gfp_mask = GFP_HIGHUSER;
inode->i_mapping = &inode->i_data;
}
/**
* get_empty_inode - obtain an inode
*
* This is called by things like the networking layer
* etc that want to get an inode without any inode
* number, or filesystems that allocate new inodes with
* no pre-existing information.
*
* On a successful return the inode pointer is returned. On a failure
* a %NULL pointer is returned. The returned inode is not on any superblock
* lists.
*/
struct inode * get_empty_inode(void)
{
static unsigned long last_ino;
struct inode * inode;
spin_lock_prefetch(&inode_lock);
inode = alloc_inode(SLAB_KERNEL);
if (inode)
{
spin_lock(&inode_lock);
inodes_stat.nr_inodes++;
list_add(&inode->i_list, &inode_in_use);
inode->i_sb = NULL;
inode->i_dev = 0;
inode->i_blkbits = 0;
inode->i_ino = ++last_ino;
inode->i_flags = 0;
atomic_set(&inode->i_count, 1);
inode->i_state = 0;
spin_unlock(&inode_lock);
clean_inode(inode);
}
return inode;
}
static inline void _unlock_new_inode(struct inode *inode)
{
/*
* This is special! We do not need the spinlock
* when clearing I_LOCK, because we're guaranteed
* that nobody else tries to do anything about the
* state of the inode when it is locked, as we
* just created it (so there can be no old holders
* that haven't tested I_LOCK).
*/
inode->i_state &= ~(I_LOCK|I_NEW);
wake_up(&inode->i_wait);
}
/*
* Broken out of create_new_inode for clarity, Calls the read_inode
* function, unlocks the populated inode, and wakes up anyone
* waiting for it to be available.
*/
static inline void populate_inode(
struct super_block *sb,
struct inode * inode,
void *opaque)
{
/* reiserfs specific hack right here. We don't
** want this to last, and are looking for VFS changes
** that will allow us to get rid of it.
** -- mason@suse.com
*/
if (sb->s_op->read_inode2) {
sb->s_op->read_inode2(inode, opaque) ;
} else {
sb->s_op->read_inode(inode);
}
_unlock_new_inode(inode);
}
/*
* This is called without the inode lock held.. Be careful.
*
* We no longer cache the sb_flags in i_flags - see fs.h
* -- rmk@arm.uk.linux.org
*/
static struct inode * get_new_inode(struct super_block *sb, unsigned long ino, struct list_head *head, find_inode_t find_actor, void *opaque, int gfp_mask)
{
struct inode * inode;
inode = alloc_inode(gfp_mask);
if (inode) {
struct inode * old;
spin_lock(&inode_lock);
/* We released the lock, so.. */
old = find_inode(sb, ino, head, find_actor, opaque);
if (!old) {
inodes_stat.nr_inodes++;
list_add(&inode->i_list, &inode_in_use);
list_add(&inode->i_hash, head);
inode->i_sb = sb;
inode->i_dev = sb->s_dev;
inode->i_blkbits = sb->s_blocksize_bits;
inode->i_ino = ino;
inode->i_flags = 0;
atomic_set(&inode->i_count, 1);
inode->i_state = I_LOCK|I_NEW;
spin_unlock(&inode_lock);
clean_inode(inode);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
*/
return inode;
}
/*
* Uhhuh, somebody else created the same inode under
* us. Use the old inode instead of the one we just
* allocated.
*/
__iget(old);
spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
}
return inode;
}
static inline unsigned long hash(struct super_block *sb, unsigned long i_ino)
{
unsigned long tmp = i_ino + ((unsigned long) sb / L1_CACHE_BYTES);
tmp = tmp + (tmp >> I_HASHBITS);
return tmp & I_HASHMASK;
}
/* Yeah, I know about quadratic hash. Maybe, later. */
/**
* iunique - get a unique inode number
* @sb: superblock
* @max_reserved: highest reserved inode number
*
* Obtain an inode number that is unique on the system for a given
* superblock. This is used by file systems that have no natural
* permanent inode numbering system. An inode number is returned that
* is higher than the reserved limit but unique.
*
* BUGS:
* With a large number of inodes live on the file system this function
* currently becomes quite slow.
*/
ino_t iunique(struct super_block *sb, ino_t max_reserved)
{
static ino_t counter = 0;
struct inode *inode;
struct list_head * head;
ino_t res;
spin_lock(&inode_lock);
retry:
if (counter > max_reserved) {
head = inode_hashtable + hash(sb,counter);
inode = find_inode(sb, res = counter++, head, NULL, NULL);
if (!inode) {
spin_unlock(&inode_lock);
return res;
}
} else {
counter = max_reserved + 1;
}
goto retry;
}
struct inode *igrab(struct inode *inode)
{
spin_lock(&inode_lock);
if (!(inode->i_state & I_FREEING))
__iget(inode);
else
/*
* Handle the case where s_op->clear_inode is not been
* called yet, and somebody is calling igrab
* while the inode is getting freed.
*/
inode = NULL;
spin_unlock(&inode_lock);
return inode;
}
/*
* This is iget4 without the read_inode portion of get_new_inode
* the filesystem gets back a new locked and hashed inode and gets
* to fill it in before unlocking it via unlock_new_inode().
*/
struct inode *icreate(struct super_block *sb, unsigned long ino, int gfp_mask)
{
struct list_head * head = inode_hashtable + hash(sb,ino);
struct inode * inode;
spin_lock(&inode_lock);
inode = find_inode(sb, ino, head, NULL, NULL);
if (inode) {
__iget(inode);
spin_unlock(&inode_lock);
wait_on_inode(inode);
return inode;
}
spin_unlock(&inode_lock);
return get_new_inode(sb, ino, head, NULL, NULL, gfp_mask);
}
void unlock_new_inode(struct inode *inode)
{
_unlock_new_inode(inode);
}
struct inode *iget4(struct super_block *sb, unsigned long ino, find_inode_t find_actor, void *opaque)
{
struct list_head * head = inode_hashtable + hash(sb,ino);
struct inode * inode;
spin_lock(&inode_lock);
inode = find_inode(sb, ino, head, find_actor, opaque);
if (inode) {
__iget(inode);
spin_unlock(&inode_lock);
wait_on_inode(inode);
return inode;
}
spin_unlock(&inode_lock);
/*
* get_new_inode() will do the right thing, re-trying the search
* in case it had to block at any point.
*/
inode = get_new_inode(sb, ino, head, find_actor, opaque, SLAB_KERNEL);
if (inode && (inode->i_state & I_NEW))
populate_inode(sb, inode, opaque);
return inode;
}
/**
* insert_inode_hash - hash an inode
* @inode: unhashed inode
*
* Add an inode to the inode hash for this superblock. If the inode
* has no superblock it is added to a separate anonymous chain.
*/
void insert_inode_hash(struct inode *inode)
{
struct list_head *head = &anon_hash_chain;
if (inode->i_sb)
head = inode_hashtable + hash(inode->i_sb, inode->i_ino);
spin_lock(&inode_lock);
list_add(&inode->i_hash, head);
spin_unlock(&inode_lock);
}
/**
* remove_inode_hash - remove an inode from the hash
* @inode: inode to unhash
*
* Remove an inode from the superblock or anonymous hash.
*/
void remove_inode_hash(struct inode *inode)
{
spin_lock(&inode_lock);
list_del(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_hash);
spin_unlock(&inode_lock);
}
/**
* 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 also then freed and may be destroyed.
*/
void iput(struct inode *inode)
{
if (inode) {
struct super_block *sb = inode->i_sb;
struct super_operations *op = NULL;
if (inode->i_state == I_CLEAR)
BUG();
if (sb && sb->s_op)
op = sb->s_op;
if (op && op->put_inode)
op->put_inode(inode);
if (!atomic_dec_and_lock(&inode->i_count, &inode_lock))
return;
if (!inode->i_nlink) {
list_del(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_hash);
list_del(&inode->i_list);
INIT_LIST_HEAD(&inode->i_list);
inode->i_state|=I_FREEING;
inodes_stat.nr_inodes--;
spin_unlock(&inode_lock);
if (inode->i_data.nrpages)
truncate_inode_pages(&inode->i_data, 0);
if (op && op->delete_inode) {
void (*delete)(struct inode *) = op->delete_inode;
if (!is_bad_inode(inode))
DQUOT_INIT(inode);
/* s_op->delete_inode internally recalls clear_inode() */
delete(inode);
} else
clear_inode(inode);
if (inode->i_state != I_CLEAR)
BUG();
} else {
if (!list_empty(&inode->i_hash)) {
if (!(inode->i_state & (I_DIRTY|I_LOCK))) {
list_del(&inode->i_list);
list_add(&inode->i_list, &inode_unused);
}
inodes_stat.nr_unused++;
spin_unlock(&inode_lock);
if (!sb || (sb->s_flags & MS_ACTIVE))
return;
write_inode_now(inode, 1);
spin_lock(&inode_lock);
inodes_stat.nr_unused--;
list_del_init(&inode->i_hash);
}
list_del_init(&inode->i_list);
inode->i_state|=I_FREEING;
inodes_stat.nr_inodes--;
spin_unlock(&inode_lock);
if (inode->i_data.nrpages)
truncate_inode_pages(&inode->i_data, 0);
clear_inode(inode);
}
destroy_inode(inode);
}
}
void force_delete(struct inode *inode)
{
/*
* Kill off unused inodes ... iput() will unhash and
* delete the inode if we set i_nlink to zero.
*/
if (atomic_read(&inode->i_count) == 1)
inode->i_nlink = 0;
}
/**
* 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.
*/
int bmap(struct inode * inode, int block)
{
int res = 0;
if (inode->i_mapping->a_ops->bmap)
res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
return res;
}
/*
* Initialize the hash tables.
*/
void __init inode_init(unsigned long mempages)
{
struct list_head *head;
unsigned long order;
unsigned int nr_hash;
int i;
mempages >>= (14 - PAGE_SHIFT);
mempages *= sizeof(struct list_head);
for (order = 0; ((1UL << order) << PAGE_SHIFT) < mempages; order++)
;
do {
unsigned long tmp;
nr_hash = (1UL << order) * PAGE_SIZE /
sizeof(struct list_head);
i_hash_mask = (nr_hash - 1);
tmp = nr_hash;
i_hash_shift = 0;
while ((tmp >>= 1UL) != 0UL)
i_hash_shift++;
inode_hashtable = (struct list_head *)
__get_free_pages(GFP_ATOMIC, order);
} while (inode_hashtable == NULL && --order >= 0);
printk("Inode-cache hash table entries: %d (order: %ld, %ld bytes)\n",
nr_hash, order, (PAGE_SIZE << order));
if (!inode_hashtable)
panic("Failed to allocate inode hash table\n");
head = inode_hashtable;
i = nr_hash;
do {
INIT_LIST_HEAD(head);
head++;
i--;
} while (i);
/* inode slab cache */
inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode),
0, SLAB_HWCACHE_ALIGN, init_once,
NULL);
if (!inode_cachep)
panic("cannot create inode slab cache");
unused_inodes_flush_task.routine = try_to_sync_unused_inodes;
}
/**
* update_atime - update the access time
* @inode: inode accessed
*
* Update the accessed time on an inode and mark it for writeback.
* This function automatically handles read only file systems and media,
* as well as the "noatime" flag and inode specific "noatime" markers.
*/
void update_atime (struct inode *inode)
{
if (inode->i_atime == CURRENT_TIME)
return;
if ( IS_NOATIME (inode) ) return;
if ( IS_NODIRATIME (inode) && S_ISDIR (inode->i_mode) ) return;
if ( IS_RDONLY (inode) ) return;
inode->i_atime = CURRENT_TIME;
mark_inode_dirty_sync (inode);
} /* End Function update_atime */
/*
* Quota functions that want to walk the inode lists..
*/
#ifdef CONFIG_QUOTA
/* Functions back in dquot.c */
void put_dquot_list(struct list_head *);
int remove_inode_dquot_ref(struct inode *, short, struct list_head *);
void remove_dquot_ref(struct super_block *sb, short type)
{
struct inode *inode;
struct list_head *act_head;
LIST_HEAD(tofree_head);
if (!sb->dq_op)
return; /* nothing to do */
/* We have to be protected against other CPUs */
lock_kernel(); /* This lock is for quota code */
spin_lock(&inode_lock); /* This lock is for inodes code */
list_for_each(act_head, &inode_in_use) {
inode = list_entry(act_head, struct inode, i_list);
if (inode->i_sb == sb && IS_QUOTAINIT(inode))
remove_inode_dquot_ref(inode, type, &tofree_head);
}
list_for_each(act_head, &inode_unused) {
inode = list_entry(act_head, struct inode, i_list);
if (inode->i_sb == sb && IS_QUOTAINIT(inode))
remove_inode_dquot_ref(inode, type, &tofree_head);
}
list_for_each(act_head, &sb->s_dirty) {
inode = list_entry(act_head, struct inode, i_list);
if (IS_QUOTAINIT(inode))
remove_inode_dquot_ref(inode, type, &tofree_head);
}
list_for_each(act_head, &sb->s_locked_inodes) {
inode = list_entry(act_head, struct inode, i_list);
if (IS_QUOTAINIT(inode))
remove_inode_dquot_ref(inode, type, &tofree_head);
}
spin_unlock(&inode_lock);
unlock_kernel();
put_dquot_list(&tofree_head);
}
#endif
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