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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: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Hugh Dickins 2005-09-03 15:54:32 -07:00 committed by Linus Torvalds
parent b0d9bcd4bb
commit e2244ec2ef
1 changed files with 16 additions and 9 deletions
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25
mm/swapfile.c
View File

@ -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;
@ -1470,25 +1475,27 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
if (error)
goto bad_swap;
}
if (swapfilesize && maxpages > swapfilesize) {
printk(KERN_WARNING
"Swap area shorter than signature indicates\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;
}
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;
down(&swapon_sem);
swap_list_lock();