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fuse: umount should wait for all requests

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fuse_abort_conn() does not guarantee that all async requests have actually
finished aborting (i.e. their ->end() function is called).  This could
actually result in still used inodes after umount.

Add a helper to wait until all requests are fully done.  This is done by
looking at the "num_waiting" counter.  When this counter drops to zero, we
can be sure that no more requests are outstanding.

Fixes: 0d8e84b043 ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2018-07-26 16:13:11 +02:00
parent 45ff350bbd
commit b8f95e5d13
3 changed files with 22 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
fs/fuse/dev.c
View file

@ -127,6 +127,16 @@ static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
return !fc->initialized || (for_background && fc->blocked);
}
static void fuse_drop_waiting(struct fuse_conn *fc)
{
if (fc->connected) {
atomic_dec(&fc->num_waiting);
} else if (atomic_dec_and_test(&fc->num_waiting)) {
/* wake up aborters */
wake_up_all(&fc->blocked_waitq);
}
}
static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
bool for_background)
{
@ -175,7 +185,7 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
return req;
out:
atomic_dec(&fc->num_waiting);
fuse_drop_waiting(fc);
return ERR_PTR(err);
}
@ -285,7 +295,7 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
if (test_bit(FR_WAITING, &req->flags)) {
__clear_bit(FR_WAITING, &req->flags);
atomic_dec(&fc->num_waiting);
fuse_drop_waiting(fc);
}
if (req->stolen_file)
@ -371,7 +381,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
struct fuse_iqueue *fiq = &fc->iq;
if (test_and_set_bit(FR_FINISHED, &req->flags))
goto out_put_req;
goto put_request;
spin_lock(&fiq->waitq.lock);
list_del_init(&req->intr_entry);
@ -400,7 +410,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
wake_up(&req->waitq);
if (req->end)
req->end(fc, req);
out_put_req:
put_request:
fuse_put_request(fc, req);
}
@ -2143,6 +2153,11 @@ void fuse_abort_conn(struct fuse_conn *fc, bool is_abort)
}
EXPORT_SYMBOL_GPL(fuse_abort_conn);
void fuse_wait_aborted(struct fuse_conn *fc)
{
wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
}
int fuse_dev_release(struct inode *inode, struct file *file)
{
struct fuse_dev *fud = fuse_get_dev(file);

1
fs/fuse/fuse_i.h
View file

@ -862,6 +862,7 @@ void fuse_request_send_background_locked(struct fuse_conn *fc,
/* Abort all requests */
void fuse_abort_conn(struct fuse_conn *fc, bool is_abort);
void fuse_wait_aborted(struct fuse_conn *fc);
/**
* Invalidate inode attributes

2
fs/fuse/inode.c
View file

@ -394,6 +394,8 @@ static void fuse_put_super(struct super_block *sb)
fuse_send_destroy(fc);
fuse_abort_conn(fc, false);
fuse_wait_aborted(fc);
mutex_lock(&fuse_mutex);
list_del(&fc->entry);
fuse_ctl_remove_conn(fc);