iomap: Allow filesystem to call iomap_dio_complete without i_rwsem
This is to avoid the deadlock caused in btrfs because of O_DIRECT |
O_DSYNC.
Filesystems such as btrfs require i_rwsem while performing sync on a
file. iomap_dio_rw() is called under i_rw_sem. This leads to a
deadlock because of:
iomap_dio_complete()
generic_write_sync()
btrfs_sync_file()
Separate out iomap_dio_complete() from iomap_dio_rw(), so filesystems
can call iomap_dio_complete() after unlocking i_rwsem.
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Signed-off-by: Goldwyn Rodrigues <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 4d1d3c3..172b339 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -13,6 +13,7 @@
struct address_space;
struct fiemap_extent_info;
struct inode;
+struct iomap_dio;
struct iomap_writepage_ctx;
struct iov_iter;
struct kiocb;
@@ -258,6 +259,10 @@ struct iomap_dio_ops {
ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
bool wait_for_completion);
+struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
+ const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
+ bool wait_for_completion);
+ssize_t iomap_dio_complete(struct iomap_dio *dio);
int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
#ifdef CONFIG_SWAP
