static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
void *data)
{
struct mpage_data *mpd = data;
struct bio *bio = mpd->bio;
struct address_space *mapping = page->mapping;
struct inode *inode = page->mapping->host;
const unsigned blkbits = inode->i_blkbits;
unsigned long end_index;
const unsigned blocks_per_page = PAGE_CACHE_SIZE >> blkbits;
sector_t last_block;
sector_t block_in_file;
sector_t blocks[MAX_BUF_PER_PAGE];
unsigned page_block;
unsigned first_unmapped = blocks_per_page;
struct block_device *bdev = NULL;
int boundary = 0;
sector_t boundary_block = 0;
struct block_device *boundary_bdev = NULL;
int length;
struct buffer_head map_bh;
loff_t i_size = i_size_read(inode);
int ret = 0;
int wr = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
if (page_has_buffers(page)) {
struct buffer_head *head = page_buffers(page);
struct buffer_head *bh = head;
/* If they're all mapped and dirty, do it */
page_block = 0;
do {
BUG_ON(buffer_locked(bh));
if (!buffer_mapped(bh)) {
/*
* unmapped dirty buffers are created by
* __set_page_dirty_buffers -> mmapped data
*/
if (buffer_dirty(bh))
goto confused;
if (first_unmapped == blocks_per_page)
first_unmapped = page_block;
continue;
}
if (first_unmapped != blocks_per_page)
goto confused; /* hole -> non-hole */
if (!buffer_dirty(bh) || !buffer_uptodate(bh))
goto confused;
if (page_block) {
if (bh->b_blocknr != blocks[page_block-1] + 1)
goto confused;
}
blocks[page_block++] = bh->b_blocknr;
boundary = buffer_boundary(bh);
if (boundary) {
boundary_block = bh->b_blocknr;
boundary_bdev = bh->b_bdev;
}
bdev = bh->b_bdev;
} while ((bh = bh->b_this_page) != head);
if (first_unmapped)
goto page_is_mapped;
/*
* Page has buffers, but they are all unmapped. The page was
* created by pagein or read over a hole which was handled by
* block_read_full_page(). If this address_space is also
* using mpage_readpages then this can rarely happen.
*/
goto confused;
}
/*
* The page has no buffers: map it to disk
*/
BUG_ON(!PageUptodate(page));
block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
last_block = (i_size - 1) >> blkbits;
map_bh.b_page = page;
for (page_block = 0; page_block < blocks_per_page; ) {
map_bh.b_state = 0;
map_bh.b_size = 1 << blkbits;
if (mpd->get_block(inode, block_in_file, &map_bh, 1))
goto confused;
if (buffer_new(&map_bh))
unmap_underlying_metadata(map_bh.b_bdev,
map_bh.b_blocknr);
if (buffer_boundary(&map_bh)) {
boundary_block = map_bh.b_blocknr;
boundary_bdev = map_bh.b_bdev;
}
if (page_block) {
if (map_bh.b_blocknr != blocks[page_block-1] + 1)
goto confused;
}
blocks[page_block++] = map_bh.b_blocknr;
boundary = buffer_boundary(&map_bh);
bdev = map_bh.b_bdev;
if (block_in_file == last_block)
break;
block_in_file++;
}
BUG_ON(page_block == 0);
first_unmapped = page_block;
page_is_mapped:
end_index = i_size >> PAGE_CACHE_SHIFT;
if (page->index >= end_index) {
/*
* The page straddles i_size. It must be zeroed out on each
* and every writepage invocation because it may be mmapped.
* "A file is mapped in multiples of the page size. For a file
* that is not a multiple of the page size, the remaining memory
* is zeroed when mapped, and writes to that region are not
* written out to the file."
*/
unsigned offset = i_size & (PAGE_CACHE_SIZE - 1);
if (page->index > end_index || !offset)
goto confused;
zero_user_segment(page, offset, PAGE_CACHE_SIZE);
}
/*
* This page will go to BIO. Do we need to send this BIO off first?
*/
if (bio && mpd->last_block_in_bio != blocks[0] - 1)
bio = mpage_bio_submit(wr, bio);
alloc_new:
if (bio == NULL) {
if (first_unmapped == blocks_per_page) {
if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),
page, wbc)) {
clean_buffers(page, first_unmapped);
goto out;
}
}
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
BIO_MAX_PAGES, GFP_NOFS|__GFP_HIGH);
if (bio == NULL)
goto confused;
wbc_init_bio(wbc, bio);
}
/*
* Must try to add the page before marking the buffer clean or
* the confused fail path above (OOM) will be very confused when
* it finds all bh marked clean (i.e. it will not write anything)
*/
wbc_account_io(wbc, page, PAGE_SIZE);
length = first_unmapped << blkbits;
if (bio_add_page(bio, page, length, 0) < length) {
bio = mpage_bio_submit(wr, bio);
goto alloc_new;
}
clean_buffers(page, first_unmapped);
BUG_ON(PageWriteback(page));
set_page_writeback(page);
unlock_page(page);
if (boundary || (first_unmapped != blocks_per_page)) {
bio = mpage_bio_submit(wr, bio);
if (boundary_block) {
write_boundary_block(boundary_bdev,
boundary_block, 1 << blkbits);
}
} else {
mpd->last_block_in_bio = blocks[blocks_per_page - 1];
}
goto out;
confused:
if (bio)
bio = mpage_bio_submit(wr, bio);
if (mpd->use_writepage) {
ret = mapping->a_ops->writepage(page, wbc);
} else {
ret = -EAGAIN;
goto out;
}
/*
* The caller has a ref on the inode, so *mapping is stable
*/
mapping_set_error(mapping, ret);
out:
mpd->bio = bio;
return ret;
}
static int __read_suspend_image(struct block_device *bdev, union diskpage *cur, int noresume)
{
swp_entry_t next;
int i, nr_pgdir_pages;
#define PREPARENEXT \
{ next = cur->link.next; \
next.val = swp_offset(next) * PAGE_SIZE; \
}
if (bdev_read_page(bdev, 0, cur)) return -EIO;
if ((!memcmp("SWAP-SPACE",cur->swh.magic.magic,10)) ||
(!memcmp("SWAPSPACE2",cur->swh.magic.magic,10))) {
printk(KERN_ERR "%sThis is normal swap space\n", name_resume );
return -EINVAL;
}
PREPARENEXT; /* We have to read next position before we overwrite it */
if (!memcmp("S1",cur->swh.magic.magic,2))
memcpy(cur->swh.magic.magic,"SWAP-SPACE",10);
else if (!memcmp("S2",cur->swh.magic.magic,2))
memcpy(cur->swh.magic.magic,"SWAPSPACE2",10);
else {
if (noresume)
return -EINVAL;
panic("%sUnable to find suspended-data signature (%.10s - misspelled?\n",
name_resume, cur->swh.magic.magic);
}
if (noresume) {
/* We don't do a sanity check here: we want to restore the swap
whatever version of kernel made the suspend image;
We need to write swap, but swap is *not* enabled so
we must write the device directly */
printk("%s: Fixing swap signatures %s...\n", name_resume, resume_file);
bdev_write_page(bdev, 0, cur);
}
printk( "%sSignature found, resuming\n", name_resume );
MDELAY(1000);
if (bdev_read_page(bdev, next.val, cur)) return -EIO;
if (sanity_check(&cur->sh)) /* Is this same machine? */
return -EPERM;
PREPARENEXT;
pagedir_save = cur->sh.suspend_pagedir;
nr_copy_pages = cur->sh.num_pbes;
nr_pgdir_pages = SUSPEND_PD_PAGES(nr_copy_pages);
pagedir_order = get_bitmask_order(nr_pgdir_pages);
pagedir_nosave = (suspend_pagedir_t *)__get_free_pages(GFP_ATOMIC, pagedir_order);
if (!pagedir_nosave)
return -ENOMEM;
PRINTK( "%sReading pagedir, ", name_resume );
/* We get pages in reverse order of saving! */
for (i=nr_pgdir_pages-1; i>=0; i--) {
BUG_ON (!next.val);
cur = (union diskpage *)((char *) pagedir_nosave)+i;
if (bdev_read_page(bdev, next.val, cur)) return -EIO;
PREPARENEXT;
}
BUG_ON (next.val);
if (relocate_pagedir())
return -ENOMEM;
if (check_pagedir())
return -ENOMEM;
printk( "Reading image data (%d pages): ", nr_copy_pages );
for(i=0; i < nr_copy_pages; i++) {
swp_entry_t swap_address = (pagedir_nosave+i)->swap_address;
if (!(i%100))
printk( "." );
/* You do not need to check for overlaps...
... check_pagedir already did this work */
if (bdev_read_page(bdev, swp_offset(swap_address) * PAGE_SIZE, (char *)((pagedir_nosave+i)->address)))
return -EIO;
}
printk( "|\n" );
return 0;
}
