[PATCH] fuse: propagate async RELEASE queue errno in fuse_file_put()

[Li Wang]

fuse_file_put() queues asynchronous FUSE_RELEASE via fuse_simple_background().
When queueing fails, the failure branch always passed -ENOTCONN into
fuse_release_end(). fuse_simple_background() can however fail for multiple reasons
with different return values, such as -ENOMEM or -EINTR. Pass the actual negative
errno into fuse_release_end(). Currently, the callback does not interpret it,
but passing the real value avoids misleading future development or debug printf
that assumes -ENOTCONN meant disconnect.

Add an explicit (void)error in fuse_release_end() so builds that enable
-Wunused-parameter (for example make W=3) stay clean.

Signed-off-by: Li Wang <liwang@xxxxxxxxxx>
---
 fs/fuse/file.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 3bdab8d03373..8b7badb7721a 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -96,6 +96,8 @@ static void fuse_release_end(struct fuse_args *args, int error)
 {
 	struct fuse_release_args *ra = container_of(args, typeof(*ra), args);
 
+	(void)error;
+
 	iput(ra->inode);
 	kfree(ra);
 }
@@ -117,6 +119,8 @@ static void fuse_file_put(struct fuse_file *ff, bool sync)
 			fuse_simple_request(ff->fm, args);
 			fuse_release_end(args, 0);
 		} else {
+			int err;
+
 			/*
 			 * DAX inodes may need to issue a number of synchronous
 			 * request for clearing the mappings.
@@ -124,9 +128,10 @@ static void fuse_file_put(struct fuse_file *ff, bool sync)
 			if (ra && ra->inode && FUSE_IS_DAX(ra->inode))
 				args->may_block = true;
 			args->end = fuse_release_end;
-			if (fuse_simple_background(ff->fm, args,
-						   GFP_KERNEL | __GFP_NOFAIL))
-				fuse_release_end(args, -ENOTCONN);
+			err = fuse_simple_background(ff->fm, args,
+						     GFP_KERNEL | __GFP_NOFAIL);
+			if (err)
+				fuse_release_end(args, err);
 		}
 		kfree(ff);
 	}
-- 
2.34.1