lkml.org 
[lkml]   [2018]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.4 60/80] fuse: umount should wait for all requests
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Miklos Szeredi <mszeredi@redhat.com>

commit b8f95e5d13f5f0191dcb4b9113113d241636e7cb upstream.

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: 0d8e84b0432b ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/fuse/dev.c | 23 +++++++++++++++++++----
fs/fuse/fuse_i.h | 1 +
fs/fuse/inode.c | 2 ++
3 files changed, 22 insertions(+), 4 deletions(-)

--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -143,6 +143,16 @@ static bool fuse_block_alloc(struct fuse
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)
{
@@ -189,7 +199,7 @@ static struct fuse_req *__fuse_get_req(s
return req;

out:
- atomic_dec(&fc->num_waiting);
+ fuse_drop_waiting(fc);
return ERR_PTR(err);
}

@@ -296,7 +306,7 @@ void fuse_put_request(struct fuse_conn *

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)
@@ -382,7 +392,7 @@ static void request_end(struct fuse_conn
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);
@@ -412,7 +422,7 @@ static void request_end(struct fuse_conn
wake_up(&req->waitq);
if (req->end)
req->end(fc, req);
-out_put_req:
+put_request:
fuse_put_request(fc, req);
}

@@ -2192,6 +2202,11 @@ void fuse_abort_conn(struct fuse_conn *f
}
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);
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -842,6 +842,7 @@ void fuse_request_send_background_locked

/* Abort all requests */
void fuse_abort_conn(struct fuse_conn *fc);
+void fuse_wait_aborted(struct fuse_conn *fc);

/**
* Invalidate inode attributes
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -382,6 +382,8 @@ static void fuse_put_super(struct super_
fuse_send_destroy(fc);

fuse_abort_conn(fc);
+ fuse_wait_aborted(fc);
+
mutex_lock(&fuse_mutex);
list_del(&fc->entry);
fuse_ctl_remove_conn(fc);

\
 
 \ /
  Last update: 2018-09-03 19:13    [W:0.322 / U:2.324 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site