diff options
-rw-r--r-- | fs/fuse/dev.c | 56 | ||||
-rw-r--r-- | include/uapi/linux/fuse.h | 2 |
2 files changed, 58 insertions, 0 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 5a5fb56deb92..3c15a6b7f6f2 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1775,6 +1775,59 @@ copy_finish: return err; } +/* + * Resending all processing queue requests. + * + * During a FUSE daemon panics and failover, it is possible for some inflight + * requests to be lost and never returned. As a result, applications awaiting + * replies would become stuck forever. To address this, we can use notification + * to trigger resending of these pending requests to the FUSE daemon, ensuring + * they are properly processed again. + * + * Please note that this strategy is applicable only to idempotent requests or + * if the FUSE daemon takes careful measures to avoid processing duplicated + * non-idempotent requests. + */ +static void fuse_resend(struct fuse_conn *fc) +{ + struct fuse_dev *fud; + struct fuse_req *req, *next; + struct fuse_iqueue *fiq = &fc->iq; + LIST_HEAD(to_queue); + unsigned int i; + + spin_lock(&fc->lock); + if (!fc->connected) { + spin_unlock(&fc->lock); + return; + } + + list_for_each_entry(fud, &fc->devices, entry) { + struct fuse_pqueue *fpq = &fud->pq; + + spin_lock(&fpq->lock); + for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) + list_splice_tail_init(&fpq->processing[i], &to_queue); + spin_unlock(&fpq->lock); + } + spin_unlock(&fc->lock); + + list_for_each_entry_safe(req, next, &to_queue, list) { + __set_bit(FR_PENDING, &req->flags); + } + + spin_lock(&fiq->lock); + /* iq and pq requests are both oldest to newest */ + list_splice(&to_queue, &fiq->pending); + fiq->ops->wake_pending_and_unlock(fiq); +} + +static int fuse_notify_resend(struct fuse_conn *fc) +{ + fuse_resend(fc); + return 0; +} + static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, unsigned int size, struct fuse_copy_state *cs) { @@ -1800,6 +1853,9 @@ static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, case FUSE_NOTIFY_DELETE: return fuse_notify_delete(fc, size, cs); + case FUSE_NOTIFY_RESEND: + return fuse_notify_resend(fc); + default: fuse_copy_finish(cs); return -EINVAL; diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index a86c2cad65ad..659932eb35e1 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -216,6 +216,7 @@ * - add max_stack_depth to fuse_init_out, add FUSE_PASSTHROUGH init flag * - add backing_id to fuse_open_out, add FOPEN_PASSTHROUGH open flag * - add FUSE_NO_EXPORT_SUPPORT init flag + * - add FUSE_NOTIFY_RESEND */ #ifndef _LINUX_FUSE_H @@ -645,6 +646,7 @@ enum fuse_notify_code { FUSE_NOTIFY_STORE = 4, FUSE_NOTIFY_RETRIEVE = 5, FUSE_NOTIFY_DELETE = 6, + FUSE_NOTIFY_RESEND = 7, FUSE_NOTIFY_CODE_MAX, }; |