[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>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9f46d83..5ac5333 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1008,8 +1008,9 @@
}
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 @@
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 @@
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();