1 files changed, 49 insertions, 2 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ba1107977f2e..ed19a7d622fa 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -131,6 +131,13 @@ static void fuse_req_init_context(struct fuse_req *req)
         req->in.h.pid = current->pid;
 }
 
+void fuse_set_initialized(struct fuse_conn *fc)
+{
+        /* Make sure stores before this are seen on another CPU */
+        smp_wmb();
+        fc->initialized = 1;
+}
+
 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 {
         return !fc->initialized || (for_background && fc->blocked);
@@ -155,6 +162,8 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
                 if (intr)
                         goto out;
         }
+        /* Matches smp_wmb() in fuse_set_initialized() */
+        smp_rmb();
 
         err = -ENOTCONN;
         if (!fc->connected)
@@ -253,6 +262,8 @@ struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 
         atomic_inc(&fc->num_waiting);
         wait_event(fc->blocked_waitq, fc->initialized);
+        /* Matches smp_wmb() in fuse_set_initialized() */
+        smp_rmb();
         req = fuse_request_alloc(0);
         if (!req)
                 req = get_reserved_req(fc, file);
@@ -511,6 +522,39 @@ void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 }
 EXPORT_SYMBOL_GPL(fuse_request_send);
 
+static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
+{
+        if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
+                args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
+
+        if (fc->minor < 9) {
+                switch (args->in.h.opcode) {
+                case FUSE_LOOKUP:
+                case FUSE_CREATE:
+                case FUSE_MKNOD:
+                case FUSE_MKDIR:
+                case FUSE_SYMLINK:
+                case FUSE_LINK:
+                        args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
+                        break;
+                case FUSE_GETATTR:
+                case FUSE_SETATTR:
+                        args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
+                        break;
+                }
+        }
+        if (fc->minor < 12) {
+                switch (args->in.h.opcode) {
+                case FUSE_CREATE:
+                        args->in.args[0].size = sizeof(struct fuse_open_in);
+                        break;
+                case FUSE_MKNOD:
+                        args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
+                        break;
+                }
+        }
+}
+
 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 {
         struct fuse_req *req;
@@ -520,6 +564,9 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
         if (IS_ERR(req))
                 return PTR_ERR(req);
 
+        /* Needs to be done after fuse_get_req() so that fc->minor is valid */
+        fuse_adjust_compat(fc, args);
+
         req->in.h.opcode = args->in.h.opcode;
         req->in.h.nodeid = args->in.h.nodeid;
         req->in.numargs = args->in.numargs;
@@ -2127,7 +2174,7 @@ void fuse_abort_conn(struct fuse_conn *fc)
         if (fc->connected) {
                 fc->connected = 0;
                 fc->blocked = 0;
-                fc->initialized = 1;
+                fuse_set_initialized(fc);
                 end_io_requests(fc);
                 end_queued_requests(fc);
                 end_polls(fc);
@@ -2146,7 +2193,7 @@ int fuse_dev_release(struct inode *inode, struct file *file)
                 spin_lock(&fc->lock);
                 fc->connected = 0;
                 fc->blocked = 0;
-                fc->initialized = 1;
+                fuse_set_initialized(fc);
                 end_queued_requests(fc);
                 end_polls(fc);
                 wake_up_all(&fc->blocked_waitq);