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authorKirill Tkhai <ktkhai@virtuozzo.com>2018-08-27 18:29:37 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-09-28 16:43:22 +0200
commit2b30a533148af4f3865c0dcd619ad93ab3f4ba52 (patch)
treefd25fe80e8ff83649d05d6eda7328447909ba628 /fs/fuse
parent2a23f2b8adbe4bd584f936f7ac17a99750eed9d7 (diff)
fuse: add locking to max_background and congestion_threshold changes
Functions sequences like request_end()->flush_bg_queue() require that max_background and congestion_threshold are constant during their execution. Otherwise, checks like if (fc->num_background == fc->max_background) made in different time may behave not like expected. 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/control.c30
1 files changed, 24 insertions, 6 deletions
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index acc35819aae6..eaa0e2b21623 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -125,7 +125,12 @@ static ssize_t fuse_conn_max_background_write(struct file *file,
if (ret > 0) {
struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
if (fc) {
+ spin_lock(&fc->lock);
fc->max_background = val;
+ fc->blocked = fc->num_background >= fc->max_background;
+ if (!fc->blocked)
+ wake_up(&fc->blocked_waitq);
+ spin_unlock(&fc->lock);
fuse_conn_put(fc);
}
}
@@ -155,18 +160,31 @@ static ssize_t fuse_conn_congestion_threshold_write(struct file *file,
size_t count, loff_t *ppos)
{
unsigned uninitialized_var(val);
+ struct fuse_conn *fc;
ssize_t ret;
ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
max_user_congthresh);
- if (ret > 0) {
- struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
- if (fc) {
- fc->congestion_threshold = val;
- fuse_conn_put(fc);
+ if (ret <= 0)
+ goto out;
+ fc = fuse_ctl_file_conn_get(file);
+ if (!fc)
+ goto out;
+
+ spin_lock(&fc->lock);
+ fc->congestion_threshold = val;
+ if (fc->sb) {
+ if (fc->num_background < fc->congestion_threshold) {
+ clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
+ clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
+ } else {
+ set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
+ set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
}
}
-
+ spin_unlock(&fc->lock);
+ fuse_conn_put(fc);
+out:
return ret;
}