[mirror_ubuntu-artful-kernel.git] / mm / fadvise.c

/*
 * mm/fadvise.c
 *
 * Copyright (C) 2002, Linus Torvalds
 *
 * 11Jan2003	akpm@digeo.com
 *		Initial version.
 */

#include <linux/kernel.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
#include <linux/fadvise.h>
#include <linux/writeback.h>
#include <linux/syscalls.h>

#include <asm/unistd.h>

/*
 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
 * deactivate the pages and clear PG_Referenced.
 *
 * LINUX_FADV_ASYNC_WRITE: start async writeout of any dirty pages between file
 * offsets `offset' and `offset+len' inclusive.  Any pages which are currently
 * under writeout are skipped, whether or not they are dirty.
 *
 * LINUX_FADV_WRITE_WAIT: wait upon writeout of any dirty pages between file
 * offsets `offset' and `offset+len'.
 *
 * By combining these two operations the application may do several things:
 *
 * LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
 *
 */
asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
{
	struct file *file = fget(fd);
	struct address_space *mapping;
	struct backing_dev_info *bdi;
	loff_t endbyte;			/* inclusive */
	pgoff_t start_index;
	pgoff_t end_index;
	unsigned long nrpages;
	int ret = 0;

	if (!file)
		return -EBADF;

	if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
		ret = -ESPIPE;
		goto out;
	}

	mapping = file->f_mapping;
	if (!mapping || len < 0) {
		ret = -EINVAL;
		goto out;
	}

	if (mapping->a_ops->get_xip_page)
		/* no bad return value, but ignore advice */
		goto out;

	/* Careful about overflows. Len == 0 means "as much as possible" */
	endbyte = offset + len;
	if (!len || endbyte < len)
		endbyte = -1;
	else
		endbyte--;		/* inclusive */

	bdi = mapping->backing_dev_info;

	switch (advice) {
	case POSIX_FADV_NORMAL:
		file->f_ra.ra_pages = bdi->ra_pages;
		break;
	case POSIX_FADV_RANDOM:
		file->f_ra.ra_pages = 0;
		break;
	case POSIX_FADV_SEQUENTIAL:
		file->f_ra.ra_pages = bdi->ra_pages * 2;
		break;
	case POSIX_FADV_WILLNEED:
	case POSIX_FADV_NOREUSE:
		if (!mapping->a_ops->readpage) {
			ret = -EINVAL;
			break;
		}

		/* First and last PARTIAL page! */
		start_index = offset >> PAGE_CACHE_SHIFT;
		end_index = endbyte >> PAGE_CACHE_SHIFT;

		/* Careful about overflow on the "+1" */
		nrpages = end_index - start_index + 1;
		if (!nrpages)
			nrpages = ~0UL;
		
		ret = force_page_cache_readahead(mapping, file,
				start_index,
				max_sane_readahead(nrpages));
		if (ret > 0)
			ret = 0;
		break;
	case POSIX_FADV_DONTNEED:
		if (!bdi_write_congested(mapping->backing_dev_info))
			filemap_flush(mapping);

		/* First and last FULL page! */
		start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
		end_index = (endbyte >> PAGE_CACHE_SHIFT);

		if (end_index >= start_index)
			invalidate_mapping_pages(mapping, start_index,
						end_index);
		break;
	default:
		ret = -EINVAL;
	}
out:
	fput(file);
	return ret;
}

#ifdef __ARCH_WANT_SYS_FADVISE64

asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
{
	return sys_fadvise64_64(fd, offset, len, advice);
}

#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* mm/fadvise.c
	3	*
	4	* Copyright (C) 2002, Linus Torvalds
	5	*
	6	* 11Jan2003 akpm@digeo.com
	7	* Initial version.
	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/file.h>
	12	#include <linux/fs.h>
	13	#include <linux/mm.h>
	14	#include <linux/pagemap.h>
	15	#include <linux/backing-dev.h>
	16	#include <linux/pagevec.h>
	17	#include <linux/fadvise.h>
ebcf28e1	18	#include <linux/writeback.h>
1da177e4 LT	19	#include <linux/syscalls.h>
	20
	21	#include <asm/unistd.h>
	22
	23	/*
	24	* POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
	25	* deactivate the pages and clear PG_Referenced.
ebcf28e1 AM	26	*
	27	* LINUX_FADV_ASYNC_WRITE: start async writeout of any dirty pages between file
	28	* offsets `offset' and `offset+len' inclusive. Any pages which are currently
	29	* under writeout are skipped, whether or not they are dirty.
	30	*
	31	* LINUX_FADV_WRITE_WAIT: wait upon writeout of any dirty pages between file
	32	* offsets `offset' and `offset+len'.
	33	*
	34	* By combining these two operations the application may do several things:
	35	*
	36	* LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
	37	*
1da177e4 LT	38	*/
	39	asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
	40	{
	41	struct file *file = fget(fd);
	42	struct address_space *mapping;
	43	struct backing_dev_info *bdi;
ebcf28e1	44	loff_t endbyte; /* inclusive */
1da177e4 LT	45	pgoff_t start_index;
	46	pgoff_t end_index;
	47	unsigned long nrpages;
	48	int ret = 0;
	49
	50	if (!file)
	51	return -EBADF;
	52
87ba81db VB	53	if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
	54	ret = -ESPIPE;
	55	goto out;
	56	}
	57
1da177e4 LT	58	mapping = file->f_mapping;
	59	if (!mapping \|\| len < 0) {
	60	ret = -EINVAL;
	61	goto out;
	62	}
	63
fe77ba6f CO	64	if (mapping->a_ops->get_xip_page)
	65	/* no bad return value, but ignore advice */
	66	goto out;
	67
1da177e4 LT	68	/* Careful about overflows. Len == 0 means "as much as possible" */
	69	endbyte = offset + len;
	70	if (!len \|\| endbyte < len)
	71	endbyte = -1;
ebcf28e1 AM	72	else
ebcf28e1 AM	73	endbyte--; /* inclusive */
1da177e4 LT	74
	75	bdi = mapping->backing_dev_info;
	76
	77	switch (advice) {
	78	case POSIX_FADV_NORMAL:
	79	file->f_ra.ra_pages = bdi->ra_pages;
	80	break;
	81	case POSIX_FADV_RANDOM:
	82	file->f_ra.ra_pages = 0;
	83	break;
	84	case POSIX_FADV_SEQUENTIAL:
	85	file->f_ra.ra_pages = bdi->ra_pages * 2;
	86	break;
	87	case POSIX_FADV_WILLNEED:
	88	case POSIX_FADV_NOREUSE:
	89	if (!mapping->a_ops->readpage) {
	90	ret = -EINVAL;
	91	break;
	92	}
	93
	94	/* First and last PARTIAL page! */
	95	start_index = offset >> PAGE_CACHE_SHIFT;
ebcf28e1	96	end_index = endbyte >> PAGE_CACHE_SHIFT;
1da177e4 LT	97
	98	/* Careful about overflow on the "+1" */
	99	nrpages = end_index - start_index + 1;
	100	if (!nrpages)
	101	nrpages = ~0UL;
	102
	103	ret = force_page_cache_readahead(mapping, file,
	104	start_index,
	105	max_sane_readahead(nrpages));
	106	if (ret > 0)
	107	ret = 0;
	108	break;
	109	case POSIX_FADV_DONTNEED:
	110	if (!bdi_write_congested(mapping->backing_dev_info))
	111	filemap_flush(mapping);
	112
	113	/* First and last FULL page! */
ebcf28e1	114	start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
1da177e4 LT	115	end_index = (endbyte >> PAGE_CACHE_SHIFT);
1da177e4 LT	116
ebcf28e1 AM	117	if (end_index >= start_index)
	118	invalidate_mapping_pages(mapping, start_index,
	119	end_index);
	120	break;
1da177e4 LT	121	default:
	122	ret = -EINVAL;
	123	}
	124	out:
	125	fput(file);
	126	return ret;
	127	}
	128
	129	#ifdef __ARCH_WANT_SYS_FADVISE64
	130
	131	asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
	132	{
	133	return sys_fadvise64_64(fd, offset, len, advice);
	134	}
	135
	136	#endif