From 07e77dca8a1f17a724a9b7449f0ca02e70e9d057 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 7 Dec 2010 20:16:56 +0100 Subject: fuse: separate queue for FORGET requests Terje Malmedal reports that a fuse filesystem with 32 million inodes on a machine with lots of memory can go unresponsive for up to 30 minutes when all those inodes are evicted from the icache. The reason is that FORGET messages, sent when the inode is evicted, are queued up together with regular filesystem requests, and while the huge queue of FORGET messages are processed no other filesystem operation can proceed. Since a full fuse request structure is allocated for each inode, these take up quite a bit of memory as well. To solve these issues, create a slim 'fuse_forget_link' structure containing just the minimum of information required to send the FORGET request and chain these on a separate queue. When userspace is asking for a request make sure that FORGET and non-FORGET requests are selected fairly: for each 8 non-FORGET allow 16 FORGET requests. This will make sure FORGETs do not pile up, yet other requests are also allowed to proceed while the queued FORGETs are processed. Reported-by: Terje Malmedal Signed-off-by: Miklos Szeredi --- fs/fuse/dev.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 77 insertions(+), 9 deletions(-) (limited to 'fs/fuse/dev.c') diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 6e07696308dc..fed65303eeeb 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -251,6 +251,20 @@ static void queue_request(struct fuse_conn *fc, struct fuse_req *req) kill_fasync(&fc->fasync, SIGIO, POLL_IN); } +void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, + u64 nodeid, u64 nlookup) +{ + forget->nodeid = nodeid; + forget->nlookup = nlookup; + + spin_lock(&fc->lock); + fc->forget_list_tail->next = forget; + fc->forget_list_tail = forget; + wake_up(&fc->waitq); + kill_fasync(&fc->fasync, SIGIO, POLL_IN); + spin_unlock(&fc->lock); +} + static void flush_bg_queue(struct fuse_conn *fc) { while (fc->active_background < fc->max_background && @@ -438,12 +452,6 @@ static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req) } } -void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req) -{ - req->isreply = 0; - fuse_request_send_nowait(fc, req); -} - void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) { req->isreply = 1; @@ -896,9 +904,15 @@ static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, return err; } +static int forget_pending(struct fuse_conn *fc) +{ + return fc->forget_list_head.next != NULL; +} + static int request_pending(struct fuse_conn *fc) { - return !list_empty(&fc->pending) || !list_empty(&fc->interrupts); + return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) || + forget_pending(fc); } /* Wait until a request is available on the pending list */ @@ -960,6 +974,50 @@ __releases(fc->lock) return err ? err : reqsize; } +static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc) +{ + struct fuse_forget_link *forget = fc->forget_list_head.next; + + fc->forget_list_head.next = forget->next; + if (fc->forget_list_head.next == NULL) + fc->forget_list_tail = &fc->forget_list_head; + + return forget; +} + +static int fuse_read_single_forget(struct fuse_conn *fc, + struct fuse_copy_state *cs, + size_t nbytes) +__releases(fc->lock) +{ + int err; + struct fuse_forget_link *forget = dequeue_forget(fc); + struct fuse_forget_in arg = { + .nlookup = forget->nlookup, + }; + struct fuse_in_header ih = { + .opcode = FUSE_FORGET, + .nodeid = forget->nodeid, + .unique = fuse_get_unique(fc), + .len = sizeof(ih) + sizeof(arg), + }; + + spin_unlock(&fc->lock); + kfree(forget); + if (nbytes < ih.len) + return -EINVAL; + + err = fuse_copy_one(cs, &ih, sizeof(ih)); + if (!err) + err = fuse_copy_one(cs, &arg, sizeof(arg)); + fuse_copy_finish(cs); + + if (err) + return err; + + return ih.len; +} + /* * Read a single request into the userspace filesystem's buffer. This * function waits until a request is available, then removes it from @@ -998,6 +1056,14 @@ static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file, return fuse_read_interrupt(fc, cs, nbytes, req); } + if (forget_pending(fc)) { + if (list_empty(&fc->pending) || fc->forget_batch-- > 0) + return fuse_read_single_forget(fc, cs, nbytes); + + if (fc->forget_batch <= -8) + fc->forget_batch = 16; + } + req = list_entry(fc->pending.next, struct fuse_req, list); req->state = FUSE_REQ_READING; list_move(&req->list, &fc->io); @@ -1090,7 +1156,7 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, if (!fc) return -EPERM; - bufs = kmalloc(pipe->buffers * sizeof (struct pipe_buffer), GFP_KERNEL); + bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); if (!bufs) return -ENOMEM; @@ -1626,7 +1692,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, if (!fc) return -EPERM; - bufs = kmalloc(pipe->buffers * sizeof (struct pipe_buffer), GFP_KERNEL); + bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); if (!bufs) return -ENOMEM; @@ -1770,6 +1836,8 @@ __acquires(fc->lock) flush_bg_queue(fc); end_requests(fc, &fc->pending); end_requests(fc, &fc->processing); + while (forget_pending(fc)) + kfree(dequeue_forget(fc)); } /* -- cgit v1.2.3