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Commit e2244ec2 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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[PATCH] swap: correct swapfile nr_good_pages 



If a regular swapfile lies on a filesystem whose blocksize is less than
PAGE_SIZE, then setup_swap_extents may have to cut the number of usable swap
pages; but sys_swapon's nr_good_pages was not expecting that.  Also,
setup_swap_extents takes no account of badpages listed in the swap header: not
worth doing so, but ensure nr_badpages is 0 for a regular swapfile.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b0d9bcd4

mm/swapfile.c

+16 −9
Original line number Diff line number Diff line
@@ -1008,8 +1008,9 @@ static int setup_swap_extents(struct swap_info_struct *sis) 
	}

	ret = 0;

	if (page_no == 0)

		ret = -EINVAL;

		page_no = 1;	/* force Empty message */

	sis->max = page_no;

	sis->pages = page_no - 1;

	sis->highest_bit = page_no - 1;

done:

	sis->curr_swap_extent = list_entry(sis->extent_list.prev,
@@ -1446,6 +1447,10 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) 
		p->highest_bit = maxpages - 1;



		error = -EINVAL;

		if (!maxpages)

			goto bad_swap;

		if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode))

			goto bad_swap;

		if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)

			goto bad_swap;
@@ -1477,18 +1482,20 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) 
		error = -EINVAL;

		goto bad_swap;

	}

	if (!nr_good_pages) {

		printk(KERN_WARNING "Empty swap-file\n");

		error = -EINVAL;

		goto bad_swap;

	}

	if (nr_good_pages) {

		p->swap_map[0] = SWAP_MAP_BAD;

		p->max = maxpages;

		p->pages = nr_good_pages;



		error = setup_swap_extents(p);

		if (error)

			goto bad_swap;

		nr_good_pages = p->pages;

	}

	if (!nr_good_pages) {

		printk(KERN_WARNING "Empty swap-file\n");

		error = -EINVAL;

		goto bad_swap;

	}



	down(&swapon_sem);

	swap_list_lock();