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-rw-r--r--mm/page_io.c145
1 files changed, 145 insertions, 0 deletions
diff --git a/mm/page_io.c b/mm/page_io.c
index 34f02923744c..78eee32ee486 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -17,6 +17,7 @@
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/swapops.h>
+#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/frontswap.h>
#include <asm/pgtable.h>
@@ -86,6 +87,98 @@ void end_swap_bio_read(struct bio *bio, int err)
bio_put(bio);
}
+int generic_swapfile_activate(struct swap_info_struct *sis,
+ struct file *swap_file,
+ sector_t *span)
+{
+ struct address_space *mapping = swap_file->f_mapping;
+ struct inode *inode = mapping->host;
+ unsigned blocks_per_page;
+ unsigned long page_no;
+ unsigned blkbits;
+ sector_t probe_block;
+ sector_t last_block;
+ sector_t lowest_block = -1;
+ sector_t highest_block = 0;
+ int nr_extents = 0;
+ int ret;
+
+ blkbits = inode->i_blkbits;
+ blocks_per_page = PAGE_SIZE >> blkbits;
+
+ /*
+ * Map all the blocks into the extent list. This code doesn't try
+ * to be very smart.
+ */
+ probe_block = 0;
+ page_no = 0;
+ last_block = i_size_read(inode) >> blkbits;
+ while ((probe_block + blocks_per_page) <= last_block &&
+ page_no < sis->max) {
+ unsigned block_in_page;
+ sector_t first_block;
+
+ first_block = bmap(inode, probe_block);
+ if (first_block == 0)
+ goto bad_bmap;
+
+ /*
+ * It must be PAGE_SIZE aligned on-disk
+ */
+ if (first_block & (blocks_per_page - 1)) {
+ probe_block++;
+ goto reprobe;
+ }
+
+ for (block_in_page = 1; block_in_page < blocks_per_page;
+ block_in_page++) {
+ sector_t block;
+
+ block = bmap(inode, probe_block + block_in_page);
+ if (block == 0)
+ goto bad_bmap;
+ if (block != first_block + block_in_page) {
+ /* Discontiguity */
+ probe_block++;
+ goto reprobe;
+ }
+ }
+
+ first_block >>= (PAGE_SHIFT - blkbits);
+ if (page_no) { /* exclude the header page */
+ if (first_block < lowest_block)
+ lowest_block = first_block;
+ if (first_block > highest_block)
+ highest_block = first_block;
+ }
+
+ /*
+ * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
+ */
+ ret = add_swap_extent(sis, page_no, 1, first_block);
+ if (ret < 0)
+ goto out;
+ nr_extents += ret;
+ page_no++;
+ probe_block += blocks_per_page;
+reprobe:
+ continue;
+ }
+ ret = nr_extents;
+ *span = 1 + highest_block - lowest_block;
+ if (page_no == 0)
+ page_no = 1; /* force Empty message */
+ sis->max = page_no;
+ sis->pages = page_no - 1;
+ sis->highest_bit = page_no - 1;
+out:
+ return ret;
+bad_bmap:
+ printk(KERN_ERR "swapon: swapfile has holes\n");
+ ret = -EINVAL;
+ goto out;
+}
+
/*
* We may have stale swap cache pages in memory: notice
* them here and get rid of the unnecessary final write.
@@ -94,6 +187,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
{
struct bio *bio;
int ret = 0, rw = WRITE;
+ struct swap_info_struct *sis = page_swap_info(page);
if (try_to_free_swap(page)) {
unlock_page(page);
@@ -105,6 +199,33 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
end_page_writeback(page);
goto out;
}
+
+ if (sis->flags & SWP_FILE) {
+ struct kiocb kiocb;
+ struct file *swap_file = sis->swap_file;
+ struct address_space *mapping = swap_file->f_mapping;
+ struct iovec iov = {
+ .iov_base = kmap(page),
+ .iov_len = PAGE_SIZE,
+ };
+
+ init_sync_kiocb(&kiocb, swap_file);
+ kiocb.ki_pos = page_file_offset(page);
+ kiocb.ki_left = PAGE_SIZE;
+ kiocb.ki_nbytes = PAGE_SIZE;
+
+ unlock_page(page);
+ ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
+ &kiocb, &iov,
+ kiocb.ki_pos, 1);
+ kunmap(page);
+ if (ret == PAGE_SIZE) {
+ count_vm_event(PSWPOUT);
+ ret = 0;
+ }
+ return ret;
+ }
+
bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
if (bio == NULL) {
set_page_dirty(page);
@@ -126,6 +247,7 @@ int swap_readpage(struct page *page)
{
struct bio *bio;
int ret = 0;
+ struct swap_info_struct *sis = page_swap_info(page);
VM_BUG_ON(!PageLocked(page));
VM_BUG_ON(PageUptodate(page));
@@ -134,6 +256,17 @@ int swap_readpage(struct page *page)
unlock_page(page);
goto out;
}
+
+ if (sis->flags & SWP_FILE) {
+ struct file *swap_file = sis->swap_file;
+ struct address_space *mapping = swap_file->f_mapping;
+
+ ret = mapping->a_ops->readpage(swap_file, page);
+ if (!ret)
+ count_vm_event(PSWPIN);
+ return ret;
+ }
+
bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
if (bio == NULL) {
unlock_page(page);
@@ -145,3 +278,15 @@ int swap_readpage(struct page *page)
out:
return ret;
}
+
+int swap_set_page_dirty(struct page *page)
+{
+ struct swap_info_struct *sis = page_swap_info(page);
+
+ if (sis->flags & SWP_FILE) {
+ struct address_space *mapping = sis->swap_file->f_mapping;
+ return mapping->a_ops->set_page_dirty(page);
+ } else {
+ return __set_page_dirty_no_writeback(page);
+ }
+}