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authorKirill Tkhai <ktkhai@virtuozzo.com>2018-08-27 18:29:56 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-09-28 16:43:23 +0200
commit63825b4e1da5a3cba79d835a5925e5daf7db3a77 (patch)
tree55581224599445dbb52801e50273cb3071f700a8 /fs/fuse
parentae2dffa39485c6fd4f22321814c7287c274b473a (diff)
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 <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/dev.c48
-rw-r--r--fs/fuse/file.c4
-rw-r--r--fs/fuse/fuse_i.h4
3 files changed, 28 insertions, 28 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);
- }
- list_add_tail(&req->list, &fc->bg_queue);
- flush_bg_queue(fc);
+ 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;
+ }
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);