From: Zach Brown <zach.brown@oracle.com>
This adds filemap_write_and_wait_range(mapping, lstart, lend) which starts
writeback and waits on a range of pages. We call this from
__blkdev_direct_IO with just the range that is going to be read by the
direct_IO read. It was lightly tested with fsx and ext3 and passed.
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/direct-io.c | 7 +++++--
25-akpm/include/linux/fs.h | 2 ++
25-akpm/mm/filemap.c | 16 ++++++++++++++++
3 files changed, 23 insertions(+), 2 deletions(-)
diff -puN fs/direct-io.c~write-and-wait-on-range-before-direct-io-read fs/direct-io.c
--- 25/fs/direct-io.c~write-and-wait-on-range-before-direct-io-read 2005-02-22 18:16:10.000000000 -0800
+++ 25-akpm/fs/direct-io.c 2005-02-22 18:16:10.000000000 -0800
@@ -1206,7 +1206,8 @@ __blockdev_direct_IO(int rw, struct kioc
*/
dio->lock_type = dio_lock_type;
if (dio_lock_type != DIO_NO_LOCKING) {
- if (rw == READ) {
+ /* watch out for a 0 len io from a tricksy fs */
+ if (rw == READ && end > offset) {
struct address_space *mapping;
mapping = iocb->ki_filp->f_mapping;
@@ -1214,7 +1215,9 @@ __blockdev_direct_IO(int rw, struct kioc
down(&inode->i_sem);
reader_with_isem = 1;
}
- retval = filemap_write_and_wait(mapping);
+
+ retval = filemap_write_and_wait_range(mapping, offset,
+ end - 1);
if (retval) {
kfree(dio);
goto out;
diff -puN include/linux/fs.h~write-and-wait-on-range-before-direct-io-read include/linux/fs.h
--- 25/include/linux/fs.h~write-and-wait-on-range-before-direct-io-read 2005-02-22 18:16:10.000000000 -0800
+++ 25-akpm/include/linux/fs.h 2005-02-22 18:16:10.000000000 -0800
@@ -1360,6 +1360,8 @@ extern int filemap_fdatawrite(struct add
extern int filemap_flush(struct address_space *);
extern int filemap_fdatawait(struct address_space *);
extern int filemap_write_and_wait(struct address_space *mapping);
+extern int filemap_write_and_wait_range(struct address_space *mapping,
+ loff_t lstart, loff_t lend);
extern void sync_supers(void);
extern void sync_filesystems(int wait);
extern void emergency_sync(void);
diff -puN mm/filemap.c~write-and-wait-on-range-before-direct-io-read mm/filemap.c
--- 25/mm/filemap.c~write-and-wait-on-range-before-direct-io-read 2005-02-22 18:16:10.000000000 -0800
+++ 25-akpm/mm/filemap.c 2005-02-22 18:16:10.000000000 -0800
@@ -336,6 +336,22 @@ int filemap_write_and_wait(struct addres
return retval;
}
+int filemap_write_and_wait_range(struct address_space *mapping,
+ loff_t lstart, loff_t lend)
+{
+ int retval = 0;
+
+ if (mapping->nrpages) {
+ retval = __filemap_fdatawrite_range(mapping, lstart, lend,
+ WB_SYNC_ALL);
+ if (retval == 0)
+ retval = wait_on_page_writeback_range(mapping,
+ lstart >> PAGE_CACHE_SHIFT,
+ lend >> PAGE_CACHE_SHIFT);
+ }
+ return retval;
+}
+
/*
* This function is used to add newly allocated pagecache pages:
* the page is new, so we can just run SetPageLocked() against it.
_