aboutsummaryrefslogtreecommitdiffstats
path: root/mm
diff options
context:
space:
mode:
authorRafael J. Wysocki <rjw@sisk.pl>2006-12-06 23:34:07 -0500
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-07 11:39:27 -0500
commit915bae9ebe41e52d71ad8b06d50e4ab26189f964 (patch)
treedaf0c9a370d3a551c1bb5beea69a3a0cfecd9885 /mm
parent3592695c363c3f3119621bdcf5ed852d6b9d1a5c (diff)
[PATCH] swsusp: use partition device and offset to identify swap areas
The Linux kernel handles swap files almost in the same way as it handles swap partitions and there are only two differences between these two types of swap areas: (1) swap files need not be contiguous, (2) the header of a swap file is not in the first block of the partition that holds it. From the swsusp's point of view (1) is not a problem, because it is already taken care of by the swap-handling code, but (2) has to be taken into consideration. In principle the location of a swap file's header may be determined with the help of appropriate filesystem driver. Unfortunately, however, it requires the filesystem holding the swap file to be mounted, and if this filesystem is journaled, it cannot be mounted during a resume from disk. For this reason we need some other means by which swap areas can be identified. For example, to identify a swap area we can use the partition that holds the area and the offset from the beginning of this partition at which the swap header is located. The following patch allows swsusp to identify swap areas this way. It changes swap_type_of() so that it takes an additional argument representing an offset of the swap header within the partition represented by its first argument. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/swapfile.c38
1 files changed, 26 insertions, 12 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index f315131db006..2bfacbac0f4c 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -427,34 +427,48 @@ void free_swap_and_cache(swp_entry_t entry)
427 427
428#ifdef CONFIG_SOFTWARE_SUSPEND 428#ifdef CONFIG_SOFTWARE_SUSPEND
429/* 429/*
430 * Find the swap type that corresponds to given device (if any) 430 * Find the swap type that corresponds to given device (if any).
431 * 431 *
432 * This is needed for software suspend and is done in such a way that inode 432 * @offset - number of the PAGE_SIZE-sized block of the device, starting
433 * aliasing is allowed. 433 * from 0, in which the swap header is expected to be located.
434 *
435 * This is needed for the suspend to disk (aka swsusp).
434 */ 436 */
435int swap_type_of(dev_t device) 437int swap_type_of(dev_t device, sector_t offset)
436{ 438{
439 struct block_device *bdev = NULL;
437 int i; 440 int i;
438 441
442 if (device)
443 bdev = bdget(device);
444
439 spin_lock(&swap_lock); 445 spin_lock(&swap_lock);
440 for (i = 0; i < nr_swapfiles; i++) { 446 for (i = 0; i < nr_swapfiles; i++) {
441 struct inode *inode; 447 struct swap_info_struct *sis = swap_info + i;
442 448
443 if (!(swap_info[i].flags & SWP_WRITEOK)) 449 if (!(sis->flags & SWP_WRITEOK))
444 continue; 450 continue;
445 451
446 if (!device) { 452 if (!bdev) {
447 spin_unlock(&swap_lock); 453 spin_unlock(&swap_lock);
448 return i; 454 return i;
449 } 455 }
450 inode = swap_info[i].swap_file->f_dentry->d_inode; 456 if (bdev == sis->bdev) {
451 if (S_ISBLK(inode->i_mode) && 457 struct swap_extent *se;
452 device == MKDEV(imajor(inode), iminor(inode))) { 458
453 spin_unlock(&swap_lock); 459 se = list_entry(sis->extent_list.next,
454 return i; 460 struct swap_extent, list);
461 if (se->start_block == offset) {
462 spin_unlock(&swap_lock);
463 bdput(bdev);
464 return i;
465 }
455 } 466 }
456 } 467 }
457 spin_unlock(&swap_lock); 468 spin_unlock(&swap_lock);
469 if (bdev)
470 bdput(bdev);
471
458 return -ENODEV; 472 return -ENODEV;
459} 473}
460 474