Reply with ENOMEM in case of failure to allocate request

Reply to request with ENOMEM in case of failure to allocate request
structure.  Otherwise the task issuing the request will just freeze up
until the filesystem daemon is killed.  Reported by Stephan Kulow

2 files changed, 27 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index eedab2f..955813b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-10-13  Miklos Szeredi <miklos@szeredi.hu>
+
+	* Reply to request with ENOMEM in case of failure to allocate
+	request structure.  Otherwise the task issuing the request will
+	just freeze up until the filesystem daemon is killed.  Reported by
+	Stephan Kulow
+
 2011-09-23  Miklos Szeredi <miklos@szeredi.hu>
 
 	* Replace daemon() function with fork().  Patch by Anatol Pomozov
diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
index b101523..e778faa 100644
--- a/lib/fuse_lowlevel.c
+++ b/lib/fuse_lowlevel.c
@@ -2273,9 +2273,28 @@ static void fuse_ll_process_buf(void *data, const struct fuse_buf *buf,
 		in = buf->mem;
 	}
 
+	if (f->debug) {
+		fprintf(stderr,
+			"unique: %llu, opcode: %s (%i), nodeid: %lu, insize: %zu, pid: %u\n",
+			(unsigned long long) in->unique,
+			opname((enum fuse_opcode) in->opcode), in->opcode,
+			(unsigned long) in->nodeid, buf->size, in->pid);
+	}
+
 	req = fuse_ll_alloc_req(f);
-	if (req == NULL)
+	if (req == NULL) {
+		struct fuse_out_header out = {
+			.unique = in->unique,
+			.error = -ENOMEM,
+		};
+		struct iovec iov = {
+			.iov_base = &out,
+			.iov_len = sizeof(struct fuse_out_header),
+		};
+
+		fuse_send_msg(f, ch, &iov, 1);
 		goto clear_pipe;
+	}
 
 	req->unique = in->unique;
 	req->ctx.uid = in->uid;
@@ -2283,14 +2302,6 @@ static void fuse_ll_process_buf(void *data, const struct fuse_buf *buf,
 	req->ctx.pid = in->pid;
 	req->ch = ch;
 
-	if (f->debug)
-		fprintf(stderr,
-			"unique: %llu, opcode: %s (%i), nodeid: %lu, insize: %zu, pid: %u\n",
-			(unsigned long long) in->unique,
-			opname((enum fuse_opcode) in->opcode), in->opcode,
-			(unsigned long) in->nodeid, buf->size, in->pid);
-
-
 	err = EIO;
 	if (!f->got_init) {
 		enum fuse_opcode expected;