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fuse: do not take fc->lock in fuse_request_send_background()

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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>
This commit is contained in:
Kirill Tkhai 2018-08-27 18:29:56 +03:00 committed by Miklos Szeredi
parent ae2dffa394
commit 63825b4e1d
3 changed files with 27 additions and 27 deletions
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46
fs/fuse/dev.c
View file

@ -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) {

4
fs/fuse/file.c
View file

@ -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:

4
fs/fuse/fuse_i.h
View file

@ -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);