[PATCH] fuse: add connection aborting

Add ability to abort a filesystem connection.

With the introduction of asynchronous reads, the ability to interrupt any
request is not enough to dissolve deadlocks, since now waiting for the request
completion (page unlocked) is independent of the actual request, so in a
deadlock all threads will be uninterruptible.

The solution is to make it possible to abort all requests, even those
currently undergoing I/O to/from userspace.  The natural interface for this is
'mount -f mountpoint', but that only works as long as the filesystem is
attached.  So also add an 'abort' attribute to the sysfs view of the
connection.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index bcb453f..e6381db 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -246,8 +246,8 @@ struct fuse_conn {
 	/** Mount is active */
 	unsigned mounted : 1;
 
-	/** Connection established, cleared on umount and device
-	    release */
+	/** Connection established, cleared on umount, connection
+	    abort and device release */
 	unsigned connected : 1;
 
 	/** Connection failed (version mismatch) */
@@ -463,6 +463,9 @@ void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
  */
 void fuse_release_background(struct fuse_req *req);
 
+/* Abort all requests */
+void fuse_abort_conn(struct fuse_conn *fc);
+
 /**
  * Get the attributes of a file
  */