fs/file.c - android_kernel_htc_msm8974 - Gitiles

 /*
  *  linux/fs/file.c
  *
  *  Copyright (C) 1998-1999, Stephen Tweedie and Bill Hawes
  *
  *  Manage the dynamic fd arrays in the process files_struct.
  */

 #include <linux/export.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/mmzone.h>
 #include <linux/time.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/file.h>
 #include <linux/fdtable.h>
 #include <linux/bitops.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/rcupdate.h>
 #include <linux/workqueue.h>
 #include <linux/crc32c.h>

 struct fdtable_defer {
 	spinlock_t lock;
 	struct work_struct wq;
 	struct fdtable *next;
 };

 int sysctl_nr_open __read_mostly = 1024*1024;
 int sysctl_nr_open_min = BITS_PER_LONG;
 int sysctl_nr_open_max = 1024 * 1024;

 static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list);

 static void *alloc_fdmem(size_t size)
 {
 	if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
 		void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
 		if (data != NULL)
 			return data;
 	}
 	return vmalloc(size);
 }

 static void free_fdmem(void *ptr)
 {
 	is_vmalloc_addr(ptr) ? vfree(ptr) : kfree(ptr);
 }

 static void __free_fdtable(struct fdtable *fdt)
 {
 	free_fdmem(fdt->fd);
 	free_fdmem(fdt->open_fds);
 	free_fdmem(fdt->user);
 	kfree(fdt);
 }

 static void free_fdtable_work(struct work_struct *work)
 {
 	struct fdtable_defer *f =
 		container_of(work, struct fdtable_defer, wq);
 	struct fdtable *fdt;

 	spin_lock_bh(&f->lock);
 	fdt = f->next;
 	f->next = NULL;
 	spin_unlock_bh(&f->lock);
 	while(fdt) {
 		struct fdtable *next = fdt->next;

 		__free_fdtable(fdt);
 		fdt = next;
 	}
 }

 void free_fdtable_rcu(struct rcu_head *rcu)
 {
 	struct fdtable *fdt = container_of(rcu, struct fdtable, rcu);
 	struct fdtable_defer *fddef;

 	BUG_ON(!fdt);

 	if (fdt->max_fds <= NR_OPEN_DEFAULT) {
 		kmem_cache_free(files_cachep,
 				container_of(fdt, struct files_struct, fdtab));
 		return;
 	}
 	if (!is_vmalloc_addr(fdt->fd) && !is_vmalloc_addr(fdt->open_fds)
 		    && !is_vmalloc_addr(fdt->user)) {
 		kfree(fdt->fd);
 		kfree(fdt->open_fds);
 		kfree(fdt->user);
 		kfree(fdt);
 	} else {
 		fddef = &get_cpu_var(fdtable_defer_list);
 		spin_lock(&fddef->lock);
 		fdt->next = fddef->next;
 		fddef->next = fdt;

 		schedule_work(&fddef->wq);
 		spin_unlock(&fddef->lock);
 		put_cpu_var(fdtable_defer_list);
 	}
 }

 static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)
 {
 	unsigned int cpy, set;

 	BUG_ON(nfdt->max_fds < ofdt->max_fds);

 	cpy = ofdt->max_fds * sizeof(struct file *);
 	set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);
 	memcpy(nfdt->fd, ofdt->fd, cpy);
 	memset((char *)(nfdt->fd) + cpy, 0, set);

 	cpy = ofdt->max_fds / BITS_PER_BYTE;
 	set = (nfdt->max_fds - ofdt->max_fds) / BITS_PER_BYTE;
 	memcpy(nfdt->open_fds, ofdt->open_fds, cpy);
 	memset((char *)(nfdt->open_fds) + cpy, 0, set);
 	memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);
 	memset((char *)(nfdt->close_on_exec) + cpy, 0, set);
 	memcpy(nfdt->user, ofdt->user,
 		ofdt->max_fds * sizeof(*nfdt->user));
 	memset(nfdt->user + ofdt->max_fds, 0,
 		(nfdt->max_fds - ofdt->max_fds) * sizeof(*nfdt->user));
 }

 static struct fdtable * alloc_fdtable(unsigned int nr)
 {
 	struct fdtable *fdt;
 	void *data;

 	nr /= (1024 / sizeof(struct file *));
 	nr = roundup_pow_of_two(nr + 1);
 	nr *= (1024 / sizeof(struct file *));
 	if (unlikely(nr > sysctl_nr_open))
 		nr = ((sysctl_nr_open - 1) | (BITS_PER_LONG - 1)) + 1;

 	fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);
 	if (!fdt)
 		goto out;
 	fdt->max_fds = nr;
 	data = alloc_fdmem(nr * sizeof(struct file *));
 	if (!data)
 		goto out_fdt;
 	fdt->fd = data;

 	data = alloc_fdmem(max_t(size_t,
 				 2 * nr / BITS_PER_BYTE, L1_CACHE_BYTES));
 	if (!data)
 		goto out_arr;
 	fdt->open_fds = data;
 	data += nr / BITS_PER_BYTE;
 	fdt->close_on_exec = data;
 	fdt->next = NULL;
 	data = alloc_fdmem(sizeof(*fdt->user) * nr);
 	if (!data)
 		goto out_open;
 	fdt->user = (struct fdt_user*) data;

 	return fdt;

 out_open:
 	free_fdmem(fdt->open_fds);
 out_arr:
 	free_fdmem(fdt->fd);
 out_fdt:
 	kfree(fdt);
 out:
 	return NULL;
 }

 static int expand_fdtable(struct files_struct *files, int nr)
 	__releases(files->file_lock)
 	__acquires(files->file_lock)
 {
 	struct fdtable *new_fdt, *cur_fdt;

 	spin_unlock(&files->file_lock);
 	new_fdt = alloc_fdtable(nr);
 	spin_lock(&files->file_lock);
 	if (!new_fdt)
 		return -ENOMEM;
 	if (unlikely(new_fdt->max_fds <= nr)) {
 		__free_fdtable(new_fdt);
 		return -EMFILE;
 	}
 	cur_fdt = files_fdtable(files);
 	if (nr >= cur_fdt->max_fds) {

 		copy_fdtable(new_fdt, cur_fdt);
 		rcu_assign_pointer(files->fdt, new_fdt);
 		if (cur_fdt->max_fds > NR_OPEN_DEFAULT)
 			free_fdtable(cur_fdt);
 	} else {

 		__free_fdtable(new_fdt);
 	}
 	return 1;
 }

 int expand_files(struct files_struct *files, int nr)
 {
 	struct fdtable *fdt;

 	fdt = files_fdtable(files);

 	if (nr >= rlimit(RLIMIT_NOFILE))
 		return -EMFILE;


 	if (nr < fdt->max_fds)
 		return 0;


 	if (nr >= sysctl_nr_open)
 		return -EMFILE;


 	return expand_fdtable(files, nr);
 }

 static int count_open_files(struct fdtable *fdt)
 {
 	int size = fdt->max_fds;
 	int i;


 	for (i = size / BITS_PER_LONG; i > 0; ) {
 		if (fdt->open_fds[--i])
 			break;
 	}
 	i = (i + 1) * BITS_PER_LONG;
 	return i;
 }

 struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
 {
 	struct files_struct *newf;
 	struct file **old_fds, **new_fds;
 	int open_files, size, i;
 	struct fdtable *old_fdt, *new_fdt;

 	*errorp = -ENOMEM;
 	newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
 	if (!newf)
 		goto out;

 	atomic_set(&newf->count, 1);

 	spin_lock_init(&newf->file_lock);
 	newf->next_fd = 0;
 	new_fdt = &newf->fdtab;
 	new_fdt->max_fds = NR_OPEN_DEFAULT;
 	new_fdt->close_on_exec = newf->close_on_exec_init;
 	new_fdt->open_fds = newf->open_fds_init;
 	new_fdt->fd = &newf->fd_array[0];
 	new_fdt->next = NULL;
 	new_fdt->user = &newf->user_array[0];

 	spin_lock(&oldf->file_lock);
 	old_fdt = files_fdtable(oldf);
 	open_files = count_open_files(old_fdt);

 	while (unlikely(open_files > new_fdt->max_fds)) {
 		spin_unlock(&oldf->file_lock);

 		if (new_fdt != &newf->fdtab)
 			__free_fdtable(new_fdt);

 		new_fdt = alloc_fdtable(open_files - 1);
 		if (!new_fdt) {
 			*errorp = -ENOMEM;
 			goto out_release;
 		}


 		if (unlikely(new_fdt->max_fds < open_files)) {
 			__free_fdtable(new_fdt);
 			*errorp = -EMFILE;
 			goto out_release;
 		}

 		spin_lock(&oldf->file_lock);
 		old_fdt = files_fdtable(oldf);
 		open_files = count_open_files(old_fdt);
 	}

 	old_fds = old_fdt->fd;
 	new_fds = new_fdt->fd;

 	memcpy(new_fdt->open_fds, old_fdt->open_fds, open_files / 8);
 	memcpy(new_fdt->close_on_exec, old_fdt->close_on_exec, open_files / 8);
 	memset(new_fdt->user, 0,
 		open_files * sizeof(*old_fdt->user));

 	for (i = open_files; i != 0; i--) {
 		struct file *f = *old_fds++;
 		if (f) {
 			get_file(f);
 		} else {
 			__clear_open_fd(open_files - i, new_fdt);
 		}
 		rcu_assign_pointer(*new_fds++, f);
 	}
 	spin_unlock(&oldf->file_lock);


 	size = (new_fdt->max_fds - open_files) * sizeof(struct file *);


 	memset(new_fds, 0, size);

 	if (new_fdt->max_fds > open_files) {
 		int left = (new_fdt->max_fds - open_files) / 8;
 		int start = open_files / BITS_PER_LONG;

 		memset(&new_fdt->open_fds[start], 0, left);
 		memset(&new_fdt->close_on_exec[start], 0, left);
 		memset(&new_fdt->user[open_files], 0,
 			(new_fdt->max_fds - open_files) * sizeof(*new_fdt->user));
 	}

 	rcu_assign_pointer(newf->fdt, new_fdt);

 	return newf;

 out_release:
 	kmem_cache_free(files_cachep, newf);
 out:
 	return NULL;
 }

 static void __devinit fdtable_defer_list_init(int cpu)
 {
 	struct fdtable_defer *fddef = &per_cpu(fdtable_defer_list, cpu);
 	spin_lock_init(&fddef->lock);
 	INIT_WORK(&fddef->wq, free_fdtable_work);
 	fddef->next = NULL;
 }

 void __init files_defer_init(void)
 {
 	int i;
 	for_each_possible_cpu(i)
 		fdtable_defer_list_init(i);
 	sysctl_nr_open_max = min((size_t)INT_MAX, ~(size_t)0/sizeof(void *)) &
 			     -BITS_PER_LONG;
 }

 struct files_struct init_files = {
 	.count		= ATOMIC_INIT(1),
 	.fdt		= &init_files.fdtab,
 	.fdtab		= {
 		.max_fds	= NR_OPEN_DEFAULT,
 		.fd		= &init_files.fd_array[0],
 		.close_on_exec	= init_files.close_on_exec_init,
 		.open_fds	= init_files.open_fds_init,
 		.user		= &init_files.user_array[0],
 	},
 	.file_lock	= __SPIN_LOCK_UNLOCKED(init_task.file_lock),
 };

 static void fdtable_usage_dump(struct fdtable *fdt)
 {
 	int i, last_crc = 0, repeats = 0;
 	char* buf;

 	buf = (char*) kmalloc(PATH_MAX, GFP_ATOMIC);
 	if (!buf) {
 		pr_err("%s: fail to alloc buffer\n", __func__);
 		return;
 	}

 	rcu_read_lock();
 	for (i = 0; i < fdt->max_fds; i++) {
 		struct file* file;
 		struct task_struct* user = NULL;
 		int this_crc, pid;
 		char* path;

 		file = fdt->fd[i];
 		if (!file)
 			continue;

 		pid = fdt->user[i].installer;

 		user = find_task_by_vpid(pid);
 		if (user)
 			get_task_struct(user);

 		path = d_path(&file->f_path, buf, PATH_MAX);

 		if (IS_ERR(path))
 			path = "<unknown>";
 		else {
 			char* spath = strstr(path, ":[");
 			if (spath) spath[0] = '\0';
 		}

 		this_crc = crc32c(pid, path, strlen(path));
 		if (this_crc != last_crc || i == fdt->max_fds - 1) {
 			if (repeats)
 				pr_warn("  < ... repeats %d time%s ... >\n",
 						repeats, repeats > 1 ? "s" : "");
 			pr_warn("%d->fd[%d] file: %s, user: %d (%s %d:%d)\n",
 					current->tgid, i, path, pid,
 					user ? user->comm : "<unknown>",
 					user ? user->tgid : -1,
 					user ? user->pid  : -1);

 			last_crc = this_crc;
 			repeats = 0;
 		} else
 			repeats++;

 		if (user)
 			put_task_struct(user);
 	}
 	rcu_read_unlock();
 	kfree(buf);
 }

 int alloc_fd(unsigned start, unsigned flags)
 {
 	struct files_struct *files = current->files;
 	unsigned int fd;
 	int error;
 	struct fdtable *fdt;

 	spin_lock(&files->file_lock);
 repeat:
 	fdt = files_fdtable(files);
 	fd = start;
 	if (fd < files->next_fd)
 		fd = files->next_fd;

 	if (fd < fdt->max_fds)
 		fd = find_next_zero_bit(fdt->open_fds, fdt->max_fds, fd);

 	error = expand_files(files, fd);
 	if (error < 0)
 		goto out;

 	if (error)
 		goto repeat;

 	if (start <= files->next_fd)
 		files->next_fd = fd + 1;

 	__set_open_fd(fd, fdt);
 	if (flags & O_CLOEXEC)
 		__set_close_on_exec(fd, fdt);
 	else
 		__clear_close_on_exec(fd, fdt);
 	memset(&fdt->user[fd], 0, sizeof(*fdt->user));
 	error = fd;
 #if 1

 	if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {
 		printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
 		rcu_assign_pointer(fdt->fd[fd], NULL);
 	}
 #endif

 out:
 	if (unlikely(error == -EMFILE)) {
 		static unsigned long debugging_ratelimit = 0;
 		const unsigned long debugging_delay_ms = 30000;

 		if (jiffies > debugging_ratelimit) {
 			debugging_ratelimit = jiffies + msecs_to_jiffies(debugging_delay_ms);

 			pr_warn("[%s] Too many open files (%d/%u), dump all fdt users:\n",
 					__func__, count_open_files(fdt), fdt->max_fds);
 			dump_stack();
 			fdtable_usage_dump(fdt);
 			pr_warn("[%s] end of dump\n", __func__);
 		}
 	}
 	spin_unlock(&files->file_lock);
 	return error;
 }
 EXPORT_SYMBOL(alloc_fd);

 int get_unused_fd(void)
 {
 	return alloc_fd(0, 0);
 }
 EXPORT_SYMBOL(get_unused_fd);
	/*
	* linux/fs/file.c
	*
	* Copyright (C) 1998-1999, Stephen Tweedie and Bill Hawes
	*
	* Manage the dynamic fd arrays in the process files_struct.
	*/

	#include <linux/export.h>
	#include <linux/fs.h>
	#include <linux/mm.h>
	#include <linux/mmzone.h>
	#include <linux/time.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/vmalloc.h>
	#include <linux/file.h>
	#include <linux/fdtable.h>
	#include <linux/bitops.h>
	#include <linux/interrupt.h>
	#include <linux/spinlock.h>
	#include <linux/rcupdate.h>
	#include <linux/workqueue.h>
	#include <linux/crc32c.h>

	struct fdtable_defer {
	spinlock_t lock;
	struct work_struct wq;
	struct fdtable *next;
	};

	int sysctl_nr_open __read_mostly = 1024*1024;
	int sysctl_nr_open_min = BITS_PER_LONG;
	int sysctl_nr_open_max = 1024 * 1024;

	static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list);

	static void *alloc_fdmem(size_t size)
	{
	if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
	void *data = kmalloc(size, GFP_KERNEL\|__GFP_NOWARN);
	if (data != NULL)
	return data;
	}
	return vmalloc(size);
	}

	static void free_fdmem(void *ptr)
	{
	is_vmalloc_addr(ptr) ? vfree(ptr) : kfree(ptr);
	}

	static void __free_fdtable(struct fdtable *fdt)
	{
	free_fdmem(fdt->fd);
	free_fdmem(fdt->open_fds);
	free_fdmem(fdt->user);
	kfree(fdt);
	}

	static void free_fdtable_work(struct work_struct *work)
	{
	struct fdtable_defer *f =
	container_of(work, struct fdtable_defer, wq);
	struct fdtable *fdt;

	spin_lock_bh(&f->lock);
	fdt = f->next;
	f->next = NULL;
	spin_unlock_bh(&f->lock);
	while(fdt) {
	struct fdtable *next = fdt->next;

	__free_fdtable(fdt);
	fdt = next;
	}
	}

	void free_fdtable_rcu(struct rcu_head *rcu)
	{
	struct fdtable *fdt = container_of(rcu, struct fdtable, rcu);
	struct fdtable_defer *fddef;

	BUG_ON(!fdt);

	if (fdt->max_fds <= NR_OPEN_DEFAULT) {
	kmem_cache_free(files_cachep,
	container_of(fdt, struct files_struct, fdtab));
	return;
	}
	if (!is_vmalloc_addr(fdt->fd) && !is_vmalloc_addr(fdt->open_fds)
	&& !is_vmalloc_addr(fdt->user)) {
	kfree(fdt->fd);
	kfree(fdt->open_fds);
	kfree(fdt->user);
	kfree(fdt);
	} else {
	fddef = &get_cpu_var(fdtable_defer_list);
	spin_lock(&fddef->lock);
	fdt->next = fddef->next;
	fddef->next = fdt;

	schedule_work(&fddef->wq);
	spin_unlock(&fddef->lock);
	put_cpu_var(fdtable_defer_list);
	}
	}

	static void copy_fdtable(struct fdtable nfdt, struct fdtable ofdt)
	{
	unsigned int cpy, set;

	BUG_ON(nfdt->max_fds < ofdt->max_fds);

	cpy = ofdt->max_fds * sizeof(struct file *);
	set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);
	memcpy(nfdt->fd, ofdt->fd, cpy);
	memset((char *)(nfdt->fd) + cpy, 0, set);

	cpy = ofdt->max_fds / BITS_PER_BYTE;
	set = (nfdt->max_fds - ofdt->max_fds) / BITS_PER_BYTE;
	memcpy(nfdt->open_fds, ofdt->open_fds, cpy);
	memset((char *)(nfdt->open_fds) + cpy, 0, set);
	memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);
	memset((char *)(nfdt->close_on_exec) + cpy, 0, set);
	memcpy(nfdt->user, ofdt->user,
	ofdt->max_fds * sizeof(*nfdt->user));
	memset(nfdt->user + ofdt->max_fds, 0,
	(nfdt->max_fds - ofdt->max_fds) * sizeof(*nfdt->user));
	}

	static struct fdtable * alloc_fdtable(unsigned int nr)
	{
	struct fdtable *fdt;
	void *data;

	nr /= (1024 / sizeof(struct file *));
	nr = roundup_pow_of_two(nr + 1);
	nr = (1024 / sizeof(struct file ));
	if (unlikely(nr > sysctl_nr_open))
	nr = ((sysctl_nr_open - 1) \| (BITS_PER_LONG - 1)) + 1;

	fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);
	if (!fdt)
	goto out;
	fdt->max_fds = nr;
	data = alloc_fdmem(nr * sizeof(struct file *));
	if (!data)
	goto out_fdt;
	fdt->fd = data;

	data = alloc_fdmem(max_t(size_t,
	2 * nr / BITS_PER_BYTE, L1_CACHE_BYTES));
	if (!data)
	goto out_arr;
	fdt->open_fds = data;
	data += nr / BITS_PER_BYTE;
	fdt->close_on_exec = data;
	fdt->next = NULL;
	data = alloc_fdmem(sizeof(fdt->user) nr);
	if (!data)
	goto out_open;
	fdt->user = (struct fdt_user*) data;

	return fdt;

	out_open:
	free_fdmem(fdt->open_fds);
	out_arr:
	free_fdmem(fdt->fd);
	out_fdt:
	kfree(fdt);
	out:
	return NULL;
	}

	static int expand_fdtable(struct files_struct *files, int nr)
	__releases(files->file_lock)
	__acquires(files->file_lock)
	{
	struct fdtable new_fdt, cur_fdt;

	spin_unlock(&files->file_lock);
	new_fdt = alloc_fdtable(nr);
	spin_lock(&files->file_lock);
	if (!new_fdt)
	return -ENOMEM;
	if (unlikely(new_fdt->max_fds <= nr)) {
	__free_fdtable(new_fdt);
	return -EMFILE;
	}
	cur_fdt = files_fdtable(files);
	if (nr >= cur_fdt->max_fds) {

	copy_fdtable(new_fdt, cur_fdt);
	rcu_assign_pointer(files->fdt, new_fdt);
	if (cur_fdt->max_fds > NR_OPEN_DEFAULT)
	free_fdtable(cur_fdt);
	} else {

	__free_fdtable(new_fdt);
	}
	return 1;
	}

	int expand_files(struct files_struct *files, int nr)
	{
	struct fdtable *fdt;

	fdt = files_fdtable(files);

	if (nr >= rlimit(RLIMIT_NOFILE))
	return -EMFILE;


	if (nr < fdt->max_fds)
	return 0;


	if (nr >= sysctl_nr_open)
	return -EMFILE;


	return expand_fdtable(files, nr);
	}

	static int count_open_files(struct fdtable *fdt)
	{
	int size = fdt->max_fds;
	int i;


	for (i = size / BITS_PER_LONG; i > 0; ) {
	if (fdt->open_fds[--i])
	break;
	}
	i = (i + 1) * BITS_PER_LONG;
	return i;
	}

	struct files_struct dup_fd(struct files_struct oldf, int *errorp)
	{
	struct files_struct *newf;
	struct file old_fds, new_fds;
	int open_files, size, i;
	struct fdtable old_fdt, new_fdt;

	*errorp = -ENOMEM;
	newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
	if (!newf)
	goto out;

	atomic_set(&newf->count, 1);

	spin_lock_init(&newf->file_lock);
	newf->next_fd = 0;
	new_fdt = &newf->fdtab;
	new_fdt->max_fds = NR_OPEN_DEFAULT;
	new_fdt->close_on_exec = newf->close_on_exec_init;
	new_fdt->open_fds = newf->open_fds_init;
	new_fdt->fd = &newf->fd_array[0];
	new_fdt->next = NULL;
	new_fdt->user = &newf->user_array[0];

	spin_lock(&oldf->file_lock);
	old_fdt = files_fdtable(oldf);
	open_files = count_open_files(old_fdt);

	while (unlikely(open_files > new_fdt->max_fds)) {
	spin_unlock(&oldf->file_lock);

	if (new_fdt != &newf->fdtab)
	__free_fdtable(new_fdt);

	new_fdt = alloc_fdtable(open_files - 1);
	if (!new_fdt) {
	*errorp = -ENOMEM;
	goto out_release;
	}


	if (unlikely(new_fdt->max_fds < open_files)) {
	__free_fdtable(new_fdt);
	*errorp = -EMFILE;
	goto out_release;
	}

	spin_lock(&oldf->file_lock);
	old_fdt = files_fdtable(oldf);
	open_files = count_open_files(old_fdt);
	}

	old_fds = old_fdt->fd;
	new_fds = new_fdt->fd;

	memcpy(new_fdt->open_fds, old_fdt->open_fds, open_files / 8);
	memcpy(new_fdt->close_on_exec, old_fdt->close_on_exec, open_files / 8);
	memset(new_fdt->user, 0,
	open_files * sizeof(*old_fdt->user));

	for (i = open_files; i != 0; i--) {
	struct file f = old_fds++;
	if (f) {
	get_file(f);
	} else {
	__clear_open_fd(open_files - i, new_fdt);
	}
	rcu_assign_pointer(*new_fds++, f);
	}
	spin_unlock(&oldf->file_lock);


	size = (new_fdt->max_fds - open_files) * sizeof(struct file *);


	memset(new_fds, 0, size);

	if (new_fdt->max_fds > open_files) {
	int left = (new_fdt->max_fds - open_files) / 8;
	int start = open_files / BITS_PER_LONG;

	memset(&new_fdt->open_fds[start], 0, left);
	memset(&new_fdt->close_on_exec[start], 0, left);
	memset(&new_fdt->user[open_files], 0,
	(new_fdt->max_fds - open_files) * sizeof(*new_fdt->user));
	}

	rcu_assign_pointer(newf->fdt, new_fdt);

	return newf;

	out_release:
	kmem_cache_free(files_cachep, newf);
	out:
	return NULL;
	}

	static void __devinit fdtable_defer_list_init(int cpu)
	{
	struct fdtable_defer *fddef = &per_cpu(fdtable_defer_list, cpu);
	spin_lock_init(&fddef->lock);
	INIT_WORK(&fddef->wq, free_fdtable_work);
	fddef->next = NULL;
	}

	void __init files_defer_init(void)
	{
	int i;
	for_each_possible_cpu(i)
	fdtable_defer_list_init(i);
	sysctl_nr_open_max = min((size_t)INT_MAX, ~(size_t)0/sizeof(void *)) &
	-BITS_PER_LONG;
	}

	struct files_struct init_files = {
	.count = ATOMIC_INIT(1),
	.fdt = &init_files.fdtab,
	.fdtab = {
	.max_fds = NR_OPEN_DEFAULT,
	.fd = &init_files.fd_array[0],
	.close_on_exec = init_files.close_on_exec_init,
	.open_fds = init_files.open_fds_init,
	.user = &init_files.user_array[0],
	},
	.file_lock = __SPIN_LOCK_UNLOCKED(init_task.file_lock),
	};

	static void fdtable_usage_dump(struct fdtable *fdt)
	{
	int i, last_crc = 0, repeats = 0;
	char* buf;

	buf = (char*) kmalloc(PATH_MAX, GFP_ATOMIC);
	if (!buf) {
	pr_err("%s: fail to alloc buffer\n", __func__);
	return;
	}

	rcu_read_lock();
	for (i = 0; i < fdt->max_fds; i++) {
	struct file* file;
	struct task_struct* user = NULL;
	int this_crc, pid;
	char* path;

	file = fdt->fd[i];
	if (!file)
	continue;

	pid = fdt->user[i].installer;

	user = find_task_by_vpid(pid);
	if (user)
	get_task_struct(user);

	path = d_path(&file->f_path, buf, PATH_MAX);

	if (IS_ERR(path))
	path = "<unknown>";
	else {
	char* spath = strstr(path, ":[");
	if (spath) spath[0] = '\0';
	}

	this_crc = crc32c(pid, path, strlen(path));
	if (this_crc != last_crc \|\| i == fdt->max_fds - 1) {
	if (repeats)
	pr_warn(" < ... repeats %d time%s ... >\n",
	repeats, repeats > 1 ? "s" : "");
	pr_warn("%d->fd[%d] file: %s, user: %d (%s %d:%d)\n",
	current->tgid, i, path, pid,
	user ? user->comm : "<unknown>",
	user ? user->tgid : -1,
	user ? user->pid : -1);

	last_crc = this_crc;
	repeats = 0;
	} else
	repeats++;

	if (user)
	put_task_struct(user);
	}
	rcu_read_unlock();
	kfree(buf);
	}

	int alloc_fd(unsigned start, unsigned flags)
	{
	struct files_struct *files = current->files;
	unsigned int fd;
	int error;
	struct fdtable *fdt;

	spin_lock(&files->file_lock);
	repeat:
	fdt = files_fdtable(files);
	fd = start;
	if (fd < files->next_fd)
	fd = files->next_fd;

	if (fd < fdt->max_fds)
	fd = find_next_zero_bit(fdt->open_fds, fdt->max_fds, fd);

	error = expand_files(files, fd);
	if (error < 0)
	goto out;

	if (error)
	goto repeat;

	if (start <= files->next_fd)
	files->next_fd = fd + 1;

	__set_open_fd(fd, fdt);
	if (flags & O_CLOEXEC)
	__set_close_on_exec(fd, fdt);
	else
	__clear_close_on_exec(fd, fdt);
	memset(&fdt->user[fd], 0, sizeof(*fdt->user));
	error = fd;
	#if 1

	if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {
	printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
	rcu_assign_pointer(fdt->fd[fd], NULL);
	}
	#endif

	out:
	if (unlikely(error == -EMFILE)) {
	static unsigned long debugging_ratelimit = 0;
	const unsigned long debugging_delay_ms = 30000;

	if (jiffies > debugging_ratelimit) {
	debugging_ratelimit = jiffies + msecs_to_jiffies(debugging_delay_ms);

	pr_warn("[%s] Too many open files (%d/%u), dump all fdt users:\n",
	__func__, count_open_files(fdt), fdt->max_fds);
	dump_stack();
	fdtable_usage_dump(fdt);
	pr_warn("[%s] end of dump\n", __func__);
	}
	}
	spin_unlock(&files->file_lock);
	return error;
	}
	EXPORT_SYMBOL(alloc_fd);

	int get_unused_fd(void)
	{
	return alloc_fd(0, 0);
	}
	EXPORT_SYMBOL(get_unused_fd);