There were two code paths direct-io writes could
take. When daemon/server side did not set FOPEN_DIRECT_IO
fuse_cache_write_iter -> direct_write_fallback
and with FOPEN_DIRECT_IO being set
fuse_direct_write_iter
Advantage of fuse_direct_write_iter is that it has optimizations
for parallel DIO writes - it might only take a shared inode lock,
instead of the exclusive lock.
With commits b5a2a3a0b776/80e4f25262f9 the fuse_direct_write_iter
path also handles concurrent page IO (dirty flush and page release),
just the condition on fc->direct_io_relax had to be removed.
Performance wise this basically gives the same improvements as
commit 153524053bbb, just O_DIRECT is sufficient, without the need
that server side sets FOPEN_DIRECT_IO
(it has to set FOPEN_PARALLEL_DIRECT_WRITES), though.
Cc: Hao Xu <howeyxu@xxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
Cc: Dharmendra Singh <dsingh@xxxxxxx>
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
fs/fuse/file.c | 27 +++++++++------------------
1 file changed, 9 insertions(+), 18 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 1cdb6327511e..a5414f46d254 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1338,15 +1338,8 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (err)
goto out;
- if (iocb->ki_flags & IOCB_DIRECT) {
- written = generic_file_direct_write(iocb, from);
- if (written < 0 || !iov_iter_count(from))
- goto out;
- written = direct_write_fallback(iocb, from, written,
- fuse_perform_write(iocb, from));
- } else {
- written = fuse_perform_write(iocb, from);
- }
+ written = fuse_perform_write(iocb, from);
+
out:
inode_unlock(inode);
if (written > 0)
@@ -1441,19 +1434,16 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
int err = 0;
struct fuse_io_args *ia;
unsigned int max_pages;
- bool fopen_direct_io = ff->open_flags & FOPEN_DIRECT_IO;
max_pages = iov_iter_npages(iter, fc->max_pages);
ia = fuse_io_alloc(io, max_pages);
if (!ia)
return -ENOMEM;
- if (fopen_direct_io && fc->direct_io_relax) {
- res = filemap_write_and_wait_range(mapping, pos, pos + count - 1);
- if (res) {
- fuse_io_free(ia);
- return res;
- }
+ 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)
@@ -1463,7 +1453,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
inode_unlock(inode);
}
- if (fopen_direct_io && write) {
+ if (write) {
res = invalidate_inode_pages2_range(mapping, idx_from, idx_to);
if (res) {
fuse_io_free(ia);
@@ -1646,7 +1636,8 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (FUSE_IS_DAX(inode))
return fuse_dax_write_iter(iocb, from);
- if (!(ff->open_flags & FOPEN_DIRECT_IO))
+ if (!(ff->open_flags & FOPEN_DIRECT_IO) &&
+ !(iocb->ki_flags & IOCB_DIRECT))
return fuse_cache_write_iter(iocb, from);
else
return fuse_direct_write_iter(iocb, from);
--
2.39.2
