vm_compressor_backing_file.c   [plain text]

/*
 * Copyright (c) 2000-2013 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#include <stdint.h>
#include <sys/fcntl.h>
#include <sys/vnode_internal.h>
#include <sys/vnode.h>
#include <sys/kauth.h>
#include <sys/mount_internal.h>
#include <sys/buf_internal.h>
#include <kern/debug.h>
#include <kern/kalloc.h>
#include <sys/cprotect.h>
#include <sys/disk.h>
#include <vm/vm_protos.h>
#include <vm/vm_pageout.h>

void vm_swapfile_open(const char *path, vnode_t *vp);
void vm_swapfile_close(uint64_t path, vnode_t vp);
int vm_swapfile_preallocate(vnode_t vp, uint64_t *size);
uint64_t vm_swapfile_get_blksize(vnode_t vp);
uint64_t vm_swapfile_get_transfer_size(vnode_t vp);
int vm_swapfile_io(vnode_t vp, uint64_t offset, uint64_t start, int npages, int flags);

void
vm_swapfile_open(const char *path, vnode_t *vp)
{
	int error = 0;
	vfs_context_t	ctx = vfs_context_current();

	if ((error = vnode_open(path, (O_CREAT | FREAD | FWRITE), S_IRUSR | S_IWUSR, 0, vp, ctx))) {
		printf("Failed to open swap file %d\n", error);
		*vp = NULL;
		return;
	}	

	vnode_put(*vp);
}

uint64_t
vm_swapfile_get_blksize(vnode_t vp)
{
	return ((uint64_t)vfs_devblocksize(vnode_mount(vp)));
}

uint64_t
vm_swapfile_get_transfer_size(vnode_t vp)
{
	return((uint64_t)vp->v_mount->mnt_vfsstat.f_iosize);
}

int unlink1(vfs_context_t, struct nameidata *, int);

void
vm_swapfile_close(uint64_t path_addr, vnode_t vp)
{
	struct nameidata nd;
	vfs_context_t context = vfs_context_current();
	int error = 0;

	vnode_getwithref(vp);
	vnode_close(vp, 0, context);
	
	NDINIT(&nd, DELETE, OP_UNLINK, AUDITVNPATH1, UIO_SYSSPACE,
	       path_addr, context);

	error = unlink1(context, &nd, 0);
}

int
vm_swapfile_preallocate(vnode_t vp, uint64_t *size)
{
	int		error = 0;
	uint64_t	file_size = 0;
	vfs_context_t	ctx = NULL;


	ctx = vfs_context_current();

#if CONFIG_PROTECT
	{
#if 0	// <rdar://11771612>

		if ((error = cp_vnode_setclass(vp, PROTECTION_CLASS_F))) {
			if(config_protect_bug) {
				printf("swap protection class set failed with %d\n", error);
			} else {
				panic("swap protection class set failed with %d\n", error);
			}
		}
#endif
		/* initialize content protection keys manually */
		if ((error = cp_handle_vnop(vp, CP_WRITE_ACCESS, 0)) != 0) {
			printf("Content Protection key failure on swap: %d\n", error);
			vnode_put(vp);
			vp = NULL;
			goto done;
 		}
	}
#endif

	/*
  	 * This check exists because dynamic_pager creates the 1st swapfile,
	 * swapfile0, for us from user-space in a supported manner (with IO_NOZEROFILL etc).
	 * 
	 * If dynamic_pager, in the future, discontinues creating that file,
	 * then we need to change this check to a panic / assert or return an error.
	 * That's because we can't be sure if the file has been created correctly.
	 */

	if ((error = vnode_size(vp, (off_t*) &file_size, ctx)) != 0) {

		printf("vnode_size (existing files) for swap files failed: %d\n", error);
		goto done;
	} else {
	
		if (file_size == 0) {

			error = vnode_setsize(vp, *size, IO_NOZEROFILL, ctx);
		
			if (error) {
				printf("vnode_setsize for swap files failed: %d\n", error);
				goto done;
			}
		} else {

			*size = file_size;
		}
	}

	vnode_lock_spin(vp);
	SET(vp->v_flag, VSWAP);
	vnode_unlock(vp);
done:
	return error;
}

int
vm_swapfile_io(vnode_t vp, uint64_t offset, uint64_t start, int npages, int flags)
{
	int error = 0;
	uint64_t io_size = npages * PAGE_SIZE_64;
#if 1
	kern_return_t	kr = KERN_SUCCESS;
	upl_t		upl = NULL;
	unsigned int	count = 0;
	int		upl_create_flags = 0, upl_control_flags = 0;
	upl_size_t	upl_size = 0;

	upl_create_flags = UPL_SET_INTERNAL | UPL_SET_LITE;
	upl_control_flags = UPL_IOSYNC;

	if ((flags & SWAP_READ) == FALSE) {
		upl_create_flags |= UPL_COPYOUT_FROM;
	}
 
	upl_size = io_size;
	kr = vm_map_create_upl( kernel_map,
				start,
				&upl_size,
				&upl,
				NULL,
				&count,
				&upl_create_flags);

	if (kr != KERN_SUCCESS || (upl_size != io_size)) {
		panic("vm_map_create_upl failed with %d\n", kr);
	}

	if (flags & SWAP_READ) {
		vnode_pagein(vp,
			      upl,
			      0,
			      offset,
			      io_size,
			      upl_control_flags | UPL_IGNORE_VALID_PAGE_CHECK,
			      &error);
		if (error) {
#if DEBUG
			printf("vm_swapfile_io: vnode_pagein failed with %d (vp: %p, offset: 0x%llx, size:%llu)\n", error, vp, offset, io_size);
#else /* DEBUG */
			printf("vm_swapfile_io: vnode_pagein failed with %d.\n", error);
#endif /* DEBUG */
		}
	
	} else {
		vnode_pageout(vp,
			      upl,
			      0,
			      offset,
			      io_size,
			      upl_control_flags,
			      &error);
		if (error) {
#if DEBUG
			printf("vm_swapfile_io: vnode_pageout failed with %d (vp: %p, offset: 0x%llx, size:%llu)\n", error, vp, offset, io_size);
#else /* DEBUG */
			printf("vm_swapfile_io: vnode_pageout failed with %d.\n", error);
#endif /* DEBUG */
		}
	}
	return error;

#else /* 1 */
	vfs_context_t ctx;
	ctx = vfs_context_kernel();
		
	error = vn_rdwr((flags & SWAP_READ) ? UIO_READ : UIO_WRITE, vp, (caddr_t)start, io_size, offset,
		UIO_SYSSPACE, IO_SYNC | IO_NODELOCKED | IO_UNIT | IO_NOCACHE | IO_SWAP_DISPATCH, vfs_context_ucred(ctx), (int *) 0, vfs_context_proc(ctx));

	if (error) {
		printf("vn_rdwr: Swap I/O failed with %d\n", error);
	}
	return error;
#endif /* 1 */
}


#define MAX_BATCH_TO_TRIM	256

u_int32_t vnode_trim_list (vnode_t vp, struct trim_list *tl)
{
	int		error = 0;
	int		trim_index = 0;
	u_int32_t	blocksize = 0;
	struct vnode	*devvp;
	dk_extent_t	*extents;
	dk_unmap_t	unmap;

	if ( !(vp->v_mount->mnt_ioflags & MNT_IOFLAGS_UNMAP_SUPPORTED))
		return (ENOTSUP);

	if (tl == NULL)
		return (0);

	/*
	 * Get the underlying device vnode and physical block size
	 */
	devvp = vp->v_mount->mnt_devvp;
	blocksize = vp->v_mount->mnt_devblocksize;

	extents = kalloc(sizeof(dk_extent_t) * MAX_BATCH_TO_TRIM);

	memset (&unmap, 0, sizeof(dk_unmap_t));
	unmap.extents = extents;

	while (tl) {
		daddr64_t	io_blockno;	/* Block number corresponding to the start of the extent */
		size_t		io_bytecount;	/* Number of bytes in current extent for the specified range */
		size_t		trimmed;
		size_t		remaining_length;
		off_t		current_offset; 

		current_offset = tl->tl_offset;
		remaining_length = tl->tl_length;
		trimmed = 0;
		
		/* 
		 * We may not get the entire range from tl_offset -> tl_offset+tl_length in a single
		 * extent from the blockmap call.  Keep looping/going until we are sure we've hit
		 * the whole range or if we encounter an error.
		 */
		while (trimmed < tl->tl_length) {
			/*
			 * VNOP_BLOCKMAP will tell us the logical to physical block number mapping for the
			 * specified offset.  It returns blocks in contiguous chunks, so if the logical range is 
			 * broken into multiple extents, it must be called multiple times, increasing the offset
			 * in each call to ensure that the entire range is covered.
			 */
			error = VNOP_BLOCKMAP (vp, current_offset, remaining_length, 
					       &io_blockno, &io_bytecount, NULL, VNODE_READ, NULL);

			if (error) {
				goto trim_exit;
			}

			extents[trim_index].offset = (uint64_t) io_blockno * (u_int64_t) blocksize;
			extents[trim_index].length = io_bytecount;

			trim_index++;

			if (trim_index == MAX_BATCH_TO_TRIM) {

				unmap.extentsCount = trim_index;
				error = VNOP_IOCTL(devvp, DKIOCUNMAP, (caddr_t)&unmap, 0, vfs_context_kernel());

				if (error) {
					goto trim_exit;
				}
				trim_index = 0;
			}
			trimmed += io_bytecount;
			current_offset += io_bytecount;
			remaining_length -= io_bytecount;
		}
		tl = tl->tl_next;
	}
	if (trim_index) {

		unmap.extentsCount = trim_index;
		error = VNOP_IOCTL(devvp, DKIOCUNMAP, (caddr_t)&unmap, 0, vfs_context_kernel());
	}
trim_exit:
	kfree(extents, sizeof(dk_extent_t) * MAX_BATCH_TO_TRIM);

	return error;
}