/*
* This is the worker routine which does all the work of mapping the disk
* blocks and constructs largest possible bios, submits them for IO if the
* blocks are not contiguous on the disk.
*
* We pass a buffer_head back and forth and use its buffer_mapped() flag to
* represent the validity of its disk mapping and to decide when to do the next
* get_block() call.
*/
static struct bio *
do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
sector_t *last_block_in_bio, struct buffer_head *map_bh,
unsigned long *first_logical_block, get_block_t get_block,
gfp_t gfp)
{
struct inode *inode = page->mapping->host;
const unsigned blkbits = inode->i_blkbits;
const unsigned blocks_per_page = PAGE_CACHE_SIZE >> blkbits;
const unsigned blocksize = 1 << blkbits;
sector_t block_in_file;
sector_t last_block;
sector_t last_block_in_file;
sector_t blocks[MAX_BUF_PER_PAGE];
unsigned page_block;
unsigned first_hole = blocks_per_page;
struct block_device *bdev = NULL;
int length;
int fully_mapped = 1;
unsigned nblocks;
unsigned relative_block;
if (page_has_buffers(page))
goto confused;
block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
last_block = block_in_file + nr_pages * blocks_per_page;
last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
if (last_block > last_block_in_file)
last_block = last_block_in_file;
page_block = 0;
/*
* Map blocks using the result from the previous get_blocks call first.
*/
nblocks = map_bh->b_size >> blkbits;
if (buffer_mapped(map_bh) && block_in_file > *first_logical_block &&
block_in_file < (*first_logical_block + nblocks)) {
unsigned map_offset = block_in_file - *first_logical_block;
unsigned last = nblocks - map_offset;
for (relative_block = 0; ; relative_block++) {
if (relative_block == last) {
clear_buffer_mapped(map_bh);
break;
}
if (page_block == blocks_per_page)
break;
blocks[page_block] = map_bh->b_blocknr + map_offset +
relative_block;
page_block++;
block_in_file++;
}
bdev = map_bh->b_bdev;
}
/*
* Then do more get_blocks calls until we are done with this page.
*/
map_bh->b_page = page;
while (page_block < blocks_per_page) {
map_bh->b_state = 0;
map_bh->b_size = 0;
if (block_in_file < last_block) {
map_bh->b_size = (last_block-block_in_file) << blkbits;
if (get_block(inode, block_in_file, map_bh, 0))
goto confused;
*first_logical_block = block_in_file;
}
if (!buffer_mapped(map_bh)) {
fully_mapped = 0;
if (first_hole == blocks_per_page)
first_hole = page_block;
page_block++;
block_in_file++;
continue;
}
/* some filesystems will copy data into the page during
* the get_block call, in which case we don't want to
* read it again. map_buffer_to_page copies the data
* we just collected from get_block into the page's buffers
* so readpage doesn't have to repeat the get_block call
*/
if (buffer_uptodate(map_bh)) {
map_buffer_to_page(page, map_bh, page_block);
goto confused;
}
if (first_hole != blocks_per_page)
goto confused; /* hole -> non-hole */
/* Contiguous blocks? */
if (page_block && blocks[page_block-1] != map_bh->b_blocknr-1)
goto confused;
nblocks = map_bh->b_size >> blkbits;
for (relative_block = 0; ; relative_block++) {
if (relative_block == nblocks) {
clear_buffer_mapped(map_bh);
break;
} else if (page_block == blocks_per_page)
break;
blocks[page_block] = map_bh->b_blocknr+relative_block;
page_block++;
block_in_file++;
}
bdev = map_bh->b_bdev;
}
if (first_hole != blocks_per_page) {
zero_user_segment(page, first_hole << blkbits, PAGE_CACHE_SIZE);
if (first_hole == 0) {
SetPageUptodate(page);
unlock_page(page);
goto out;
}
} else if (fully_mapped) {
SetPageMappedToDisk(page);
}
if (fully_mapped && blocks_per_page == 1 && !PageUptodate(page) &&
cleancache_get_page(page) == 0) {
SetPageUptodate(page);
goto confused;
}
/*
* This page will go to BIO. Do we need to send this BIO off first?
*/
if (bio && (*last_block_in_bio != blocks[0] - 1))
bio = mpage_bio_submit(READ, bio);
alloc_new:
if (bio == NULL) {
if (first_hole == blocks_per_page) {
if (!bdev_read_page(bdev, blocks[0] << (blkbits - 9),
page))
goto out;
}
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
min_t(int, nr_pages, BIO_MAX_PAGES), gfp);
if (bio == NULL)
goto confused;
}
length = first_hole << blkbits;
if (bio_add_page(bio, page, length, 0) < length) {
bio = mpage_bio_submit(READ, bio);
goto alloc_new;
}
relative_block = block_in_file - *first_logical_block;
nblocks = map_bh->b_size >> blkbits;
if ((buffer_boundary(map_bh) && relative_block == nblocks) ||
(first_hole != blocks_per_page))
bio = mpage_bio_submit(READ, bio);
else
*last_block_in_bio = blocks[blocks_per_page - 1];
out:
return bio;
confused:
if (bio)
bio = mpage_bio_submit(READ, bio);
if (!PageUptodate(page))
block_read_full_page(page, get_block);
else
unlock_page(page);
goto out;
}
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;
}