From 595afaf9e6ee1b48e13ec4b8bcc8c7dee888161a Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 7 Sep 2010 13:42:41 +0200 Subject: fuse: flush background queue on connection close David Bartly reported that fuse can hang in fuse_get_req_nofail() when the connection to the filesystem server is no longer active. If bg_queue is not empty then flush_bg_queue() called from request_end() can put more requests on to the pending queue. If this happens while ending requests on the processing queue then those background requests will be queued to the pending list and never ended. Another problem is that fuse_dev_release() didn't wake up processes sleeping on blocked_waitq. Solve this by: a) flushing the background queue before calling end_requests() on the pending and processing queues b) setting blocked = 0 and waking up processes waiting on blocked_waitq() Thanks to David for an excellent bug report. Reported-by: David Bartley Signed-off-by: Miklos Szeredi CC: stable@kernel.org --- fs/fuse/dev.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 69ad053ffd7..b4fc47ff4bc 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1769,6 +1769,14 @@ __acquires(&fc->lock) } } +static void end_queued_requests(struct fuse_conn *fc) +{ + fc->max_background = UINT_MAX; + flush_bg_queue(fc); + end_requests(fc, &fc->pending); + end_requests(fc, &fc->processing); +} + /* * Abort all requests. * @@ -1795,8 +1803,7 @@ void fuse_abort_conn(struct fuse_conn *fc) fc->connected = 0; fc->blocked = 0; end_io_requests(fc); - end_requests(fc, &fc->pending); - end_requests(fc, &fc->processing); + end_queued_requests(fc); wake_up_all(&fc->waitq); wake_up_all(&fc->blocked_waitq); kill_fasync(&fc->fasync, SIGIO, POLL_IN); @@ -1811,8 +1818,9 @@ int fuse_dev_release(struct inode *inode, struct file *file) if (fc) { spin_lock(&fc->lock); fc->connected = 0; - end_requests(fc, &fc->pending); - end_requests(fc, &fc->processing); + fc->blocked = 0; + end_queued_requests(fc); + wake_up_all(&fc->blocked_waitq); spin_unlock(&fc->lock); fuse_conn_put(fc); } -- cgit v1.2.3 From b9ca67b2ddf021491a3741d9555e8ff59b2175ba Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 7 Sep 2010 13:42:41 +0200 Subject: fuse: fix lock annotations Sparse doesn't understand lock annotations of the form __releases(&foo->lock). Change them to __releases(foo->lock). Same for __acquires(). Signed-off-by: Miklos Szeredi --- fs/fuse/dev.c | 26 ++++++++++++++------------ fs/fuse/file.c | 8 ++++---- 2 files changed, 18 insertions(+), 16 deletions(-) (limited to 'fs') diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index b4fc47ff4bc..d367af1514e 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -276,7 +276,7 @@ static void flush_bg_queue(struct fuse_conn *fc) * Called with fc->lock, unlocks it */ static void request_end(struct fuse_conn *fc, struct fuse_req *req) -__releases(&fc->lock) +__releases(fc->lock) { void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; req->end = NULL; @@ -306,8 +306,8 @@ __releases(&fc->lock) static void wait_answer_interruptible(struct fuse_conn *fc, struct fuse_req *req) -__releases(&fc->lock) -__acquires(&fc->lock) +__releases(fc->lock) +__acquires(fc->lock) { if (signal_pending(current)) return; @@ -325,8 +325,8 @@ static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req) } static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) -__releases(&fc->lock) -__acquires(&fc->lock) +__releases(fc->lock) +__acquires(fc->lock) { if (!fc->no_interrupt) { /* Any signal may interrupt this */ @@ -905,8 +905,8 @@ static int request_pending(struct fuse_conn *fc) /* Wait until a request is available on the pending list */ static void request_wait(struct fuse_conn *fc) -__releases(&fc->lock) -__acquires(&fc->lock) +__releases(fc->lock) +__acquires(fc->lock) { DECLARE_WAITQUEUE(wait, current); @@ -934,7 +934,7 @@ __acquires(&fc->lock) */ static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs, size_t nbytes, struct fuse_req *req) -__releases(&fc->lock) +__releases(fc->lock) { struct fuse_in_header ih; struct fuse_interrupt_in arg; @@ -1720,8 +1720,8 @@ static unsigned fuse_dev_poll(struct file *file, poll_table *wait) * This function releases and reacquires fc->lock */ static void end_requests(struct fuse_conn *fc, struct list_head *head) -__releases(&fc->lock) -__acquires(&fc->lock) +__releases(fc->lock) +__acquires(fc->lock) { while (!list_empty(head)) { struct fuse_req *req; @@ -1744,8 +1744,8 @@ __acquires(&fc->lock) * locked). */ static void end_io_requests(struct fuse_conn *fc) -__releases(&fc->lock) -__acquires(&fc->lock) +__releases(fc->lock) +__acquires(fc->lock) { while (!list_empty(&fc->io)) { struct fuse_req *req = @@ -1770,6 +1770,8 @@ __acquires(&fc->lock) } static void end_queued_requests(struct fuse_conn *fc) +__releases(fc->lock) +__acquires(fc->lock) { fc->max_background = UINT_MAX; flush_bg_queue(fc); diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 147c1f71bdb..c8224587123 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1144,8 +1144,8 @@ static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req) /* Called under fc->lock, may release and reacquire it */ static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req) -__releases(&fc->lock) -__acquires(&fc->lock) +__releases(fc->lock) +__acquires(fc->lock) { struct fuse_inode *fi = get_fuse_inode(req->inode); loff_t size = i_size_read(req->inode); @@ -1183,8 +1183,8 @@ __acquires(&fc->lock) * Called with fc->lock */ void fuse_flush_writepages(struct inode *inode) -__releases(&fc->lock) -__acquires(&fc->lock) +__releases(fc->lock) +__acquires(fc->lock) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); -- cgit v1.2.3