[PATCH] fuse: Consider the ->big_writes for allocing fuse_req when do writing

[majianpeng <majianpeng@gmail.com>]

If fc->big_writes == 0, for write-operation it only do 4k in func fuse_fill_write_pages.
So when alloc fuse_req,we should consider this restrict in order to
do additional operations.
The additional operations are memset-opeartion in func fuse_requenst_alloc and alloc more space if nr_pages is larger than FUSE_REQ_MIN_PAGES.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
---
fs/fuse/file.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 34b80ba..c584a31 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -912,8 +912,13 @@ static ssize_t fuse_perform_write(struct file *file,
do {
struct fuse_req *req;
ssize_t count;
- unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
+ unsigned nr_pages;

+ if (!fc->big_writes)
+ nr_pages = 1;
+ else
+ nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
+
req = fuse_get_req(fc, nr_pages);
if (IS_ERR(req)) {
err = PTR_ERR(req);
-- 
1.8.2.rc2.4.g7799588