From 63825b4e1da5a3cba79d835a5925e5daf7db3a77 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Mon, 27 Aug 2018 18:29:56 +0300 Subject: [PATCH] fuse: do not take fc->lock in fuse_request_send_background() Currently, we take fc->lock there only to check for fc->connected. But this flag is changed only on connection abort, which is very rare operation. So allow checking fc->connected under just fc->bg_lock and use this lock (as well as fc->lock) when resetting fc->connected. Signed-off-by: Kirill Tkhai Signed-off-by: Miklos Szeredi --- fs/fuse/dev.c | 46 +++++++++++++++++++++++----------------------- fs/fuse/file.c | 4 +++- fs/fuse/fuse_i.h | 4 +--- 3 files changed, 27 insertions(+), 27 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index d4b9ffc6544d..071feb8cb265 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -581,42 +581,38 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) return ret; } -/* - * Called under fc->lock - * - * fc->connected must have been checked previously - */ -void fuse_request_send_background_nocheck(struct fuse_conn *fc, - struct fuse_req *req) +bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req) { - BUG_ON(!test_bit(FR_BACKGROUND, &req->flags)); + bool queued = false; + + WARN_ON(!test_bit(FR_BACKGROUND, &req->flags)); if (!test_bit(FR_WAITING, &req->flags)) { __set_bit(FR_WAITING, &req->flags); atomic_inc(&fc->num_waiting); } __set_bit(FR_ISREPLY, &req->flags); spin_lock(&fc->bg_lock); - fc->num_background++; - if (fc->num_background == fc->max_background) - fc->blocked = 1; - if (fc->num_background == fc->congestion_threshold && fc->sb) { - set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); - set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); + if (likely(fc->connected)) { + fc->num_background++; + if (fc->num_background == fc->max_background) + fc->blocked = 1; + if (fc->num_background == fc->congestion_threshold && fc->sb) { + set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); + set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); + } + list_add_tail(&req->list, &fc->bg_queue); + flush_bg_queue(fc); + queued = true; } - list_add_tail(&req->list, &fc->bg_queue); - flush_bg_queue(fc); spin_unlock(&fc->bg_lock); + + return queued; } void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) { - BUG_ON(!req->end); - spin_lock(&fc->lock); - if (fc->connected) { - fuse_request_send_background_nocheck(fc, req); - spin_unlock(&fc->lock); - } else { - spin_unlock(&fc->lock); + WARN_ON(!req->end); + if (!fuse_request_queue_background(fc, req)) { req->out.h.error = -ENOTCONN; req->end(fc, req); fuse_put_request(fc, req); @@ -2119,7 +2115,11 @@ void fuse_abort_conn(struct fuse_conn *fc, bool is_abort) struct fuse_req *req, *next; LIST_HEAD(to_end); + /* Background queuing checks fc->connected under bg_lock */ + spin_lock(&fc->bg_lock); fc->connected = 0; + spin_unlock(&fc->bg_lock); + fc->aborted = is_abort; fuse_set_initialized(fc); list_for_each_entry(fud, &fc->devices, entry) { diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 65351d43c2b6..d15c14912e72 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1487,6 +1487,7 @@ __acquires(fc->lock) struct fuse_inode *fi = get_fuse_inode(req->inode); struct fuse_write_in *inarg = &req->misc.write.in; __u64 data_size = req->num_pages * PAGE_SIZE; + bool queued; if (!fc->connected) goto out_free; @@ -1502,7 +1503,8 @@ __acquires(fc->lock) req->in.args[1].size = inarg->size; fi->writectr++; - fuse_request_send_background_nocheck(fc, req); + queued = fuse_request_queue_background(fc, req); + WARN_ON(!queued); return; out_free: diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index d6d55641a5a6..6e6eab8127a4 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -863,9 +863,7 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args); * Send a request in the background */ void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req); - -void fuse_request_send_background_nocheck(struct fuse_conn *fc, - struct fuse_req *req); +bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req); /* Abort all requests */ void fuse_abort_conn(struct fuse_conn *fc, bool is_abort);