Add block_write_full_page_endio for passing endio handler
block_write_full_page doesn't allow the caller to control what happens
when the IO is over. This adds a new call named block_write_full_page_endio
so the buffer head end_io handler can be provided by the caller.
This will be used by the ext3 data=guarded mode to do i_size updates in
a workqueue based end_io handler. end_buffer_async_write is also
exported so it can be called to do the dirty work of managing page
writeback for the higher level end_io handler.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Acked-by: Theodore Tso <tytso@mit.edu>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/buffer.c b/fs/buffer.c
index ff8bb1f..b3e5be7 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -360,7 +360,7 @@
* Completion handler for block_write_full_page() - pages which are unlocked
* during I/O, and which have PageWriteback cleared upon I/O completion.
*/
-static void end_buffer_async_write(struct buffer_head *bh, int uptodate)
+void end_buffer_async_write(struct buffer_head *bh, int uptodate)
{
char b[BDEVNAME_SIZE];
unsigned long flags;
@@ -438,10 +438,16 @@
set_buffer_async_read(bh);
}
+void mark_buffer_async_write_endio(struct buffer_head *bh,
+ bh_end_io_t *handler)
+{
+ bh->b_end_io = handler;
+ set_buffer_async_write(bh);
+}
+
void mark_buffer_async_write(struct buffer_head *bh)
{
- bh->b_end_io = end_buffer_async_write;
- set_buffer_async_write(bh);
+ mark_buffer_async_write_endio(bh, end_buffer_async_write);
}
EXPORT_SYMBOL(mark_buffer_async_write);
@@ -1615,7 +1621,8 @@
* unplugging the device queue.
*/
static int __block_write_full_page(struct inode *inode, struct page *page,
- get_block_t *get_block, struct writeback_control *wbc)
+ get_block_t *get_block, struct writeback_control *wbc,
+ bh_end_io_t *handler)
{
int err;
sector_t block;
@@ -1700,7 +1707,7 @@
continue;
}
if (test_clear_buffer_dirty(bh)) {
- mark_buffer_async_write(bh);
+ mark_buffer_async_write_endio(bh, handler);
} else {
unlock_buffer(bh);
}
@@ -1753,7 +1760,7 @@
if (buffer_mapped(bh) && buffer_dirty(bh) &&
!buffer_delay(bh)) {
lock_buffer(bh);
- mark_buffer_async_write(bh);
+ mark_buffer_async_write_endio(bh, handler);
} else {
/*
* The buffer may have been set dirty during
@@ -2679,7 +2686,8 @@
out:
ret = mpage_writepage(page, get_block, wbc);
if (ret == -EAGAIN)
- ret = __block_write_full_page(inode, page, get_block, wbc);
+ ret = __block_write_full_page(inode, page, get_block, wbc,
+ end_buffer_async_write);
return ret;
}
EXPORT_SYMBOL(nobh_writepage);
@@ -2837,9 +2845,10 @@
/*
* The generic ->writepage function for buffer-backed address_spaces
+ * this form passes in the end_io handler used to finish the IO.
*/
-int block_write_full_page(struct page *page, get_block_t *get_block,
- struct writeback_control *wbc)
+int block_write_full_page_endio(struct page *page, get_block_t *get_block,
+ struct writeback_control *wbc, bh_end_io_t *handler)
{
struct inode * const inode = page->mapping->host;
loff_t i_size = i_size_read(inode);
@@ -2848,7 +2857,8 @@
/* Is the page fully inside i_size? */
if (page->index < end_index)
- return __block_write_full_page(inode, page, get_block, wbc);
+ return __block_write_full_page(inode, page, get_block, wbc,
+ handler);
/* Is the page fully outside i_size? (truncate in progress) */
offset = i_size & (PAGE_CACHE_SIZE-1);
@@ -2871,9 +2881,20 @@
* writes to that region are not written out to the file."
*/
zero_user_segment(page, offset, PAGE_CACHE_SIZE);
- return __block_write_full_page(inode, page, get_block, wbc);
+ return __block_write_full_page(inode, page, get_block, wbc, handler);
}
+/*
+ * The generic ->writepage function for buffer-backed address_spaces
+ */
+int block_write_full_page(struct page *page, get_block_t *get_block,
+ struct writeback_control *wbc)
+{
+ return block_write_full_page_endio(page, get_block, wbc,
+ end_buffer_async_write);
+}
+
+
sector_t generic_block_bmap(struct address_space *mapping, sector_t block,
get_block_t *get_block)
{
@@ -3342,9 +3363,11 @@
EXPORT_SYMBOL(block_sync_page);
EXPORT_SYMBOL(block_truncate_page);
EXPORT_SYMBOL(block_write_full_page);
+EXPORT_SYMBOL(block_write_full_page_endio);
EXPORT_SYMBOL(cont_write_begin);
EXPORT_SYMBOL(end_buffer_read_sync);
EXPORT_SYMBOL(end_buffer_write_sync);
+EXPORT_SYMBOL(end_buffer_async_write);
EXPORT_SYMBOL(file_fsync);
EXPORT_SYMBOL(generic_block_bmap);
EXPORT_SYMBOL(generic_cont_expand_simple);