There are situations where fuse servers can become unresponsive or
stuck, for example if the server is in a deadlock. Currently, there's
no good way to detect if a server is stuck and needs to be killed
manually.
This commit adds an option for enforcing a timeout (in seconds) on
requests where if the timeout elapses without a reply from the server,
the connection will be automatically aborted.
Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx>
---
fs/fuse/dev.c | 26 +++++++++++++++++++++++++-
fs/fuse/fuse_i.h | 8 ++++++++
fs/fuse/inode.c | 7 +++++++
3 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 9eb191b5c4de..a4ec817074a2 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -40,6 +40,16 @@ static struct fuse_dev *fuse_get_dev(struct file *file)
return READ_ONCE(file->private_data);
}
+static void fuse_request_timeout(struct timer_list *timer)
+{
+ struct fuse_req *req = container_of(timer, struct fuse_req, timer);
+ struct fuse_conn *fc = req->fm->fc;
+
+ req->timer.function = NULL;
+
+ fuse_abort_conn(fc);
+}
+
static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req)
{
INIT_LIST_HEAD(&req->list);
@@ -48,6 +58,8 @@ static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req)
refcount_set(&req->count, 1);
__set_bit(FR_PENDING, &req->flags);
req->fm = fm;
+ if (fm->fc->req_timeout)
+ timer_setup(&req->timer, fuse_request_timeout, 0);
}
static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags)
@@ -283,6 +295,9 @@ void fuse_request_end(struct fuse_req *req)
struct fuse_conn *fc = fm->fc;
struct fuse_iqueue *fiq = &fc->iq;
+ if (req->timer.function)
+ timer_delete_sync(&req->timer);
+
if (test_and_set_bit(FR_FINISHED, &req->flags))
goto put_request;
@@ -393,6 +408,8 @@ static void request_wait_answer(struct fuse_req *req)
if (test_bit(FR_PENDING, &req->flags)) {
list_del(&req->list);
spin_unlock(&fiq->lock);
+ if (req->timer.function)
+ timer_delete_sync(&req->timer);
__fuse_put_request(req);
req->out.h.error = -EINTR;
return;
@@ -409,7 +426,8 @@ static void request_wait_answer(struct fuse_req *req)
static void __fuse_request_send(struct fuse_req *req)
{
- struct fuse_iqueue *fiq = &req->fm->fc->iq;
+ struct fuse_conn *fc = req->fm->fc;
+ struct fuse_iqueue *fiq = &fc->iq;
BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
spin_lock(&fiq->lock);
@@ -421,6 +439,8 @@ static void __fuse_request_send(struct fuse_req *req)
/* acquire extra reference, since request is still needed
after fuse_request_end() */
__fuse_get_request(req);
+ if (req->timer.function)
+ mod_timer(&req->timer, jiffies + fc->req_timeout);
queue_request_and_unlock(fiq, req);
request_wait_answer(req);
@@ -539,6 +559,8 @@ static bool fuse_request_queue_background(struct fuse_req *req)
if (fc->num_background == fc->max_background)
fc->blocked = 1;
list_add_tail(&req->list, &fc->bg_queue);
+ if (req->timer.function)
+ mod_timer(&req->timer, jiffies + fc->req_timeout);
flush_bg_queue(fc);
queued = true;
}
@@ -594,6 +616,8 @@ static int fuse_simple_notify_reply(struct fuse_mount *fm,
spin_lock(&fiq->lock);
if (fiq->connected) {
+ if (req->timer.function)
+ mod_timer(&req->timer, jiffies + fm->fc->req_timeout);
queue_request_and_unlock(fiq, req);
} else {
err = -ENODEV;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index f23919610313..97dacafa4289 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -435,6 +435,9 @@ struct fuse_req {
/** fuse_mount this request belongs to */
struct fuse_mount *fm;
+
+ /** timer for request replies, if timeout option is enabled */
+ struct timer_list timer;
};
struct fuse_iqueue;
@@ -574,6 +577,8 @@ struct fuse_fs_context {
enum fuse_dax_mode dax_mode;
unsigned int max_read;
unsigned int blksize;
+ /* Request timeout (in seconds). 0 = no timeout (infinite wait) */
+ unsigned int req_timeout;
const char *subtype;
/* DAX device, may be NULL */
@@ -633,6 +638,9 @@ struct fuse_conn {
/** Constrain ->max_pages to this value during feature negotiation */
unsigned int max_pages_limit;
+ /* Request timeout (in jiffies). 0 = no timeout (infinite wait) */
+ unsigned long req_timeout;
+
/** Input queue */
struct fuse_iqueue iq;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 99e44ea7d875..9e69006fc026 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -733,6 +733,7 @@ enum {
OPT_ALLOW_OTHER,
OPT_MAX_READ,
OPT_BLKSIZE,
+ OPT_REQUEST_TIMEOUT,
OPT_ERR
};
@@ -747,6 +748,7 @@ static const struct fs_parameter_spec fuse_fs_parameters[] = {
fsparam_u32 ("max_read", OPT_MAX_READ),
fsparam_u32 ("blksize", OPT_BLKSIZE),
fsparam_string ("subtype", OPT_SUBTYPE),
+ fsparam_u32 ("request_timeout", OPT_REQUEST_TIMEOUT),
{}
};
@@ -830,6 +832,10 @@ static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
ctx->blksize = result.uint_32;
break;
+ case OPT_REQUEST_TIMEOUT:
+ ctx->req_timeout = result.uint_32;
+ break;
+
default:
return -EINVAL;
}
@@ -1724,6 +1730,7 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
fc->group_id = ctx->group_id;
fc->legacy_opts_show = ctx->legacy_opts_show;
fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
+ fc->req_timeout = ctx->req_timeout * HZ;
fc->destroy = ctx->destroy;
fc->no_control = ctx->no_control;
fc->no_force_umount = ctx->no_force_umount;
--
2.43.5
