3 files changed, 38 insertions, 4 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 4dc104c0e95d..6c740f860665 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -90,7 +90,17 @@ static void __fuse_put_request(struct fuse_req *req)
 
 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
 {
-        struct fuse_req *req = fuse_request_alloc();
+        struct fuse_req *req;
+        sigset_t oldset;
+        int err;
+
+        block_sigs(&oldset);
+        err = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
+        restore_sigs(&oldset);
+        if (err)
+                return ERR_PTR(-EINTR);
+
+        req = fuse_request_alloc();
         if (!req)
                 return ERR_PTR(-ENOMEM);
 
@@ -118,6 +128,11 @@ void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req)
                 fput(req->file);
         spin_lock(&fc->lock);
         list_del(&req->bg_entry);
+        if (fc->num_background == FUSE_MAX_BACKGROUND) {
+                fc->blocked = 0;
+                wake_up_all(&fc->blocked_waitq);
+        }
+        fc->num_background--;
         spin_unlock(&fc->lock);
 }
 
@@ -195,6 +210,9 @@ static void background_request(struct fuse_conn *fc, struct fuse_req *req)
 {
         req->background = 1;
         list_add(&req->bg_entry, &fc->background);
+        fc->num_background++;
+        if (fc->num_background == FUSE_MAX_BACKGROUND)
+                fc->blocked = 1;
         if (req->inode)
                 req->inode = igrab(req->inode);
         if (req->inode2)
@@ -288,6 +306,7 @@ void request_send(struct fuse_conn *fc, struct fuse_req *req)
 static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
 {
         spin_lock(&fc->lock);
+        background_request(fc, req);
         if (fc->connected) {
                 queue_request(fc, req);
                 spin_unlock(&fc->lock);
@@ -306,9 +325,6 @@ void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req)
 void request_send_background(struct fuse_conn *fc, struct fuse_req *req)
 {
         req->isreply = 1;
-        spin_lock(&fc->lock);
-        background_request(fc, req);
-        spin_unlock(&fc->lock);
         request_send_nowait(fc, req);
 }
 
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 242e69cb1251..19c7185a7546 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -18,6 +18,9 @@
 /** Max number of pages that can be used in a single read request */
 #define FUSE_MAX_PAGES_PER_REQ 32
 
+/** Maximum number of outstanding background requests */
+#define FUSE_MAX_BACKGROUND 10
+
 /** It could be as large as PATH_MAX, but would that have any uses? */
 #define FUSE_NAME_MAX 1024
 
@@ -241,6 +244,17 @@ struct fuse_conn {
             interrupted request) */
         struct list_head background;
 
+        /** Number of requests currently in the background */
+        unsigned num_background;
+
+        /** Flag indicating if connection is blocked.  This will be
+            the case before the INIT reply is received, and if there
+            are too many outstading backgrounds requests */
+        int blocked;
+
+        /** waitq for blocked connection */
+        wait_queue_head_t blocked_waitq;
+
         /** RW semaphore for exclusion with fuse_put_super() */
         struct rw_semaphore sbput_sem;
 
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 824ebbc428ed..fd34037b0588 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -381,6 +381,7 @@ static struct fuse_conn *new_conn(void)
         if (fc) {
                 spin_lock_init(&fc->lock);
                 init_waitqueue_head(&fc->waitq);
+                init_waitqueue_head(&fc->blocked_waitq);
                 INIT_LIST_HEAD(&fc->pending);
                 INIT_LIST_HEAD(&fc->processing);
                 INIT_LIST_HEAD(&fc->io);
@@ -392,6 +393,7 @@ static struct fuse_conn *new_conn(void)
                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
                 fc->reqctr = 0;
+                fc->blocked = 1;
         }
         return fc;
 }
@@ -438,6 +440,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
         }
         fuse_put_request(fc, req);
+        fc->blocked = 0;
+        wake_up_all(&fc->blocked_waitq);
 }
 
 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)