vfs: add hooks for ext4's delayed allocation support

Export mpage_bio_submit() and __mpage_writepage() for the benefit of
ext4's delayed allocation support.   Also change __block_write_full_page
so that if buffers that have the BH_Delay flag set it will call
get_block() to get the physical block allocated, just as in the
!BH_Mapped case.

Signed-off-by: Alex Tomas <alex@clusterfs.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/buffer.c b/fs/buffer.c
index f4b0332..5fa1512 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1691,11 +1691,13 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
                         */
                        clear_buffer_dirty(bh);
                        set_buffer_uptodate(bh);
-               } else if (!buffer_mapped(bh) && buffer_dirty(bh)) {
+               } else if ((!buffer_mapped(bh) || buffer_delay(bh)) &&
+                          buffer_dirty(bh)) {
                        WARN_ON(bh->b_size != blocksize);
                        err = get_block(inode, block, bh, 1);
                        if (err)
                                goto recover;
+                       clear_buffer_delay(bh);
                        if (buffer_new(bh)) {
                                /* blockdev mappings never come here */
                                clear_buffer_new(bh);
@@ -1774,7 +1776,8 @@ recover:
        bh = head;
        /* Recovery: lock and submit the mapped buffers */
        do {
-               if (buffer_mapped(bh) && buffer_dirty(bh)) {
+               if (buffer_mapped(bh) && buffer_dirty(bh) &&
+                   !buffer_delay(bh)) {
                        lock_buffer(bh);
                        mark_buffer_async_write(bh);
                } else {

diff --git a/fs/mpage.c b/fs/mpage.c
index 235e4d3..dbcc7af 100644 (file)
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -82,7 +82,7 @@ static void mpage_end_io_write(struct bio *bio, int err)
        bio_put(bio);
 }
 
-static struct bio *mpage_bio_submit(int rw, struct bio *bio)
+struct bio *mpage_bio_submit(int rw, struct bio *bio)
 {
        bio->bi_end_io = mpage_end_io_read;
        if (rw == WRITE)
@@ -90,6 +90,7 @@ static struct bio *mpage_bio_submit(int rw, struct bio *bio)
        submit_bio(rw, bio);
        return NULL;
 }
+EXPORT_SYMBOL(mpage_bio_submit);
 
 static struct bio *
 mpage_alloc(struct block_device *bdev,
@@ -435,15 +436,9 @@ EXPORT_SYMBOL(mpage_readpage);
  * written, so it can intelligently allocate a suitably-sized BIO.  For now,
  * just allocate full-size (16-page) BIOs.
  */
-struct mpage_data {
-       struct bio *bio;
-       sector_t last_block_in_bio;
-       get_block_t *get_block;
-       unsigned use_writepage;
-};
 
-static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
-                            void *data)
+int __mpage_writepage(struct page *page, struct writeback_control *wbc,
+                     void *data)
 {
        struct mpage_data *mpd = data;
        struct bio *bio = mpd->bio;
@@ -651,6 +646,7 @@ out:
        mpd->bio = bio;
        return ret;
 }
+EXPORT_SYMBOL(__mpage_writepage);
 
 /**
  * mpage_writepages - walk the list of dirty pages of the given address space & writepage() all of them

diff --git a/include/linux/mpage.h b/include/linux/mpage.h
index 068a0c9..5c42821 100644 (file)
--- a/include/linux/mpage.h
+++ b/include/linux/mpage.h
@@ -11,11 +11,21 @@
  */
 #ifdef CONFIG_BLOCK
 
+struct mpage_data {
+       struct bio *bio;
+       sector_t last_block_in_bio;
+       get_block_t *get_block;
+       unsigned use_writepage;
+};
+
 struct writeback_control;
 
+struct bio *mpage_bio_submit(int rw, struct bio *bio);
 int mpage_readpages(struct address_space *mapping, struct list_head *pages,
                                unsigned nr_pages, get_block_t get_block);
 int mpage_readpage(struct page *page, get_block_t get_block);
+int __mpage_writepage(struct page *page, struct writeback_control *wbc,
+                     void *data);
 int mpage_writepages(struct address_space *mapping,
                struct writeback_control *wbc, get_block_t get_block);
 int mpage_writepage(struct page *page, get_block_t *get_block,