[linux-2.6-block.git] / mm / msync.c

/*
 *	linux/mm/msync.c
 *
 * Copyright (C) 1994-1999  Linus Torvalds
 */

/*
 * The msync() system call.
 */
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/syscalls.h>
#include <linux/sched.h>

/*
 * MS_SYNC syncs the entire file - including mappings.
 *
 * MS_ASYNC does not start I/O (it used to, up to 2.5.67).
 * Nor does it marks the relevant pages dirty (it used to up to 2.6.17).
 * Now it doesn't do anything, since dirty pages are properly tracked.
 *
 * The application may now run fsync() to
 * write out the dirty pages and wait on the writeout and check the result.
 * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
 * async writeout immediately.
 * So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to
 * applications.
 */
SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
{
	unsigned long end;
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	int unmapped_error = 0;
	int error = -EINVAL;

	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
		goto out;
	if (start & ~PAGE_MASK)
		goto out;
	if ((flags & MS_ASYNC) && (flags & MS_SYNC))
		goto out;
	error = -ENOMEM;
	len = (len + ~PAGE_MASK) & PAGE_MASK;
	end = start + len;
	if (end < start)
		goto out;
	error = 0;
	if (end == start)
		goto out;
	/*
	 * If the interval [start,end) covers some unmapped address ranges,
	 * just ignore them, but return -ENOMEM at the end.
	 */
	down_read(&mm->mmap_sem);
	vma = find_vma(mm, start);
	for (;;) {
		struct file *file;

		/* Still start < end. */
		error = -ENOMEM;
		if (!vma)
			goto out_unlock;
		/* Here start < vma->vm_end. */
		if (start < vma->vm_start) {
			start = vma->vm_start;
			if (start >= end)
				goto out_unlock;
			unmapped_error = -ENOMEM;
		}
		/* Here vma->vm_start <= start < vma->vm_end. */
		if ((flags & MS_INVALIDATE) &&
				(vma->vm_flags & VM_LOCKED)) {
			error = -EBUSY;
			goto out_unlock;
		}
		file = vma->vm_file;
		start = vma->vm_end;
		if ((flags & MS_SYNC) && file &&
				(vma->vm_flags & VM_SHARED)) {
			get_file(file);
			up_read(&mm->mmap_sem);
			error = vfs_fsync(file, file->f_path.dentry, 0);
			fput(file);
			if (error || start >= end)
				goto out;
			down_read(&mm->mmap_sem);
			vma = find_vma(mm, start);
		} else {
			if (start >= end) {
				error = 0;
				goto out_unlock;
			}
			vma = vma->vm_next;
		}
	}
out_unlock:
	up_read(&mm->mmap_sem);
out:
	return error ? : unmapped_error;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/mm/msync.c
	3	*
	4	* Copyright (C) 1994-1999 Linus Torvalds
	5	*/
	6
	7	/*
	8	* The msync() system call.
	9	*/
8f2e9f15	10	#include <linux/fs.h>
1da177e4 LT	11	#include <linux/mm.h>
1da177e4 LT	12	#include <linux/mman.h>
9c50823e	13	#include <linux/file.h>
1da177e4	14	#include <linux/syscalls.h>
e8edc6e0	15	#include <linux/sched.h>
1da177e4	16
1da177e4 LT	17	/*
	18	* MS_SYNC syncs the entire file - including mappings.
	19	*
204ec841 PZ	20	* MS_ASYNC does not start I/O (it used to, up to 2.5.67).
	21	* Nor does it marks the relevant pages dirty (it used to up to 2.6.17).
	22	* Now it doesn't do anything, since dirty pages are properly tracked.
	23	*
	24	* The application may now run fsync() to
1da177e4 LT	25	* write out the dirty pages and wait on the writeout and check the result.
	26	* Or the application may run fadvise(FADV_DONTNEED) against the fd to start
	27	* async writeout immediately.
16538c40	28	* So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to
1da177e4 LT	29	* applications.
1da177e4 LT	30	*/
6a6160a7	31	SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
1da177e4 LT	32	{
1da177e4 LT	33	unsigned long end;
204ec841	34	struct mm_struct *mm = current->mm;
1da177e4	35	struct vm_area_struct *vma;
676758bd AM	36	int unmapped_error = 0;
676758bd AM	37	int error = -EINVAL;
1da177e4	38
1da177e4 LT	39	if (flags & ~(MS_ASYNC \| MS_INVALIDATE \| MS_SYNC))
	40	goto out;
	41	if (start & ~PAGE_MASK)
	42	goto out;
	43	if ((flags & MS_ASYNC) && (flags & MS_SYNC))
	44	goto out;
	45	error = -ENOMEM;
	46	len = (len + ~PAGE_MASK) & PAGE_MASK;
	47	end = start + len;
	48	if (end < start)
	49	goto out;
	50	error = 0;
	51	if (end == start)
	52	goto out;
	53	/*
	54	* If the interval [start,end) covers some unmapped address ranges,
	55	* just ignore them, but return -ENOMEM at the end.
	56	*/
204ec841 PZ	57	down_read(&mm->mmap_sem);
	58	vma = find_vma(mm, start);
	59	for (;;) {
9c50823e AM	60	struct file *file;
9c50823e AM	61
204ec841 PZ	62	/* Still start < end. */
	63	error = -ENOMEM;
	64	if (!vma)
	65	goto out_unlock;
1da177e4 LT	66	/* Here start < vma->vm_end. */
1da177e4 LT	67	if (start < vma->vm_start) {
1da177e4	68	start = vma->vm_start;
204ec841 PZ	69	if (start >= end)
	70	goto out_unlock;
	71	unmapped_error = -ENOMEM;
1da177e4 LT	72	}
1da177e4 LT	73	/* Here vma->vm_start <= start < vma->vm_end. */
204ec841 PZ	74	if ((flags & MS_INVALIDATE) &&
	75	(vma->vm_flags & VM_LOCKED)) {
	76	error = -EBUSY;
	77	goto out_unlock;
1da177e4	78	}
9c50823e	79	file = vma->vm_file;
1da177e4	80	start = vma->vm_end;
204ec841	81	if ((flags & MS_SYNC) && file &&
707c21c8	82	(vma->vm_flags & VM_SHARED)) {
707c21c8	83	get_file(file);
204ec841	84	up_read(&mm->mmap_sem);
4c728ef5	85	error = vfs_fsync(file, file->f_path.dentry, 0);
707c21c8	86	fput(file);
204ec841 PZ	87	if (error \|\| start >= end)
	88	goto out;
	89	down_read(&mm->mmap_sem);
	90	vma = find_vma(mm, start);
9c50823e	91	} else {
204ec841 PZ	92	if (start >= end) {
	93	error = 0;
	94	goto out_unlock;
	95	}
9c50823e AM	96	vma = vma->vm_next;
9c50823e AM	97	}
204ec841	98	}
9c50823e	99	out_unlock:
204ec841	100	up_read(&mm->mmap_sem);
9c50823e	101	out:
204ec841	102	return error ? : unmapped_error;
1da177e4	103	}