On 2023/6/30 17:46, Hao Xu wrote:
From: Hao Xu <howeyxu@xxxxxxxxxxx>
In direct_io_relax mode, there can be shared mmaped files and thus dirty
pages in its page cache. Therefore those dirty pages should be written
back to backend before direct write to avoid data loss.
Signed-off-by: Hao Xu <howeyxu@xxxxxxxxxxx>
---
fs/fuse/file.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 176f719f8fc8..7c9167c62bf6 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1485,6 +1485,13 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
if (!ia)
return -ENOMEM;
+ if (fopen_direct_write && fc->direct_io_relax) {
+ res = filemap_write_and_wait_range(mapping, pos, pos + count - 1);
+ if (res) {
+ fuse_io_free(ia);
+ return res;
+ }
+ }
if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
if (!write)
inode_lock(inode);
Tested-by: Jiachen Zhang <zhangjiachen.jaycee@xxxxxxxxxxxxx>
Looks good to me.
By the way, the behaviour would be a first FUSE_WRITE flushing the page
cache, followed by a second FUSE_WRITE doing the direct IO. In the
future, further optimization could be first write into the page cache
and then flush the dirty page to the FUSE daemon.
Thanks,
Jiachen
