[PATCH] fuse: add number of waiting requests attribute

This patch adds the 'waiting' attribute which indicates how many filesystem
requests are currently waiting to be completed.  A non-zero value without any
filesystem activity indicates a hung or deadlocked filesystem.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 3 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index de4a0a0bda8a..c72e44b58d09 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -109,18 +109,24 @@ struct fuse_req *fuse_get_request(struct fuse_conn *fc)
         int intr;
         sigset_t oldset;
 
+        atomic_inc(&fc->num_waiting);
         block_sigs(&oldset);
         intr = down_interruptible(&fc->outstanding_sem);
         restore_sigs(&oldset);
-        return intr ? NULL : do_get_request(fc);
+        if (intr) {
+                atomic_dec(&fc->num_waiting);
+                return NULL;
+        }
+        return do_get_request(fc);
 }
 
 static void fuse_putback_request(struct fuse_conn *fc, struct fuse_req *req)
 {
         spin_lock(&fuse_lock);
-        if (req->preallocated)
+        if (req->preallocated) {
+                atomic_dec(&fc->num_waiting);
                 list_add(&req->list, &fc->unused_list);
-        else
+        } else
                 fuse_request_free(req);
 
         /* If we are in debt decrease that first */