On Fri, Nov 3, 2017 at 4:04 PM, Szymon Lukasz <noh4hss@xxxxxxxxx> wrote: > Return -ECONNABORTED when userspace tries to read from /dev/fuse after > the fuse connection was aborted via sysfs. > The patch increases FUSE_KERNEL_MINOR_VERSION. However -ECONNABORTED is > always returned, regardless of the minor version sent by userspace in > FUSE_INIT. I worry about that. I'd rather have this enabled with a capability flag negotiated in INIT. > > Info why this patch might be useful: > https://github.com/libfuse/libfuse/issues/122 > > Signed-off-by: Szymon Lukasz <noh4hss@xxxxxxxxx> > --- > fs/fuse/control.c | 2 +- > fs/fuse/dev.c | 13 ++++++++----- > fs/fuse/fuse_i.h | 8 +++++++- > fs/fuse/inode.c | 4 ++-- > include/uapi/linux/fuse.h | 5 ++++- > 5 files changed, 22 insertions(+), 10 deletions(-) > > diff --git a/fs/fuse/control.c b/fs/fuse/control.c > index b9ea99c5b5b3..eeda05a7c882 100644 > --- a/fs/fuse/control.c > +++ b/fs/fuse/control.c > @@ -35,7 +35,7 @@ static ssize_t fuse_conn_abort_write(struct file *file, const char __user *buf, > { > struct fuse_conn *fc = fuse_ctl_file_conn_get(file); > if (fc) { > - fuse_abort_conn(fc); > + fuse_abort_conn(fc, 1); > fuse_conn_put(fc); > } > return count; > diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c > index 13c65dd2d37d..b51da52b92b9 100644 > --- a/fs/fuse/dev.c > +++ b/fs/fuse/dev.c > @@ -1234,9 +1234,10 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, > if (err) > goto err_unlock; > > - err = -ENODEV; > - if (!fiq->connected) > + if (!fiq->connected) { > + err = fiq->aborted ? -ECONNABORTED : -ENODEV; > goto err_unlock; > + } > > if (!list_empty(&fiq->interrupts)) { > req = list_entry(fiq->interrupts.next, struct fuse_req, > @@ -1287,7 +1288,7 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, > spin_lock(&fpq->lock); > clear_bit(FR_LOCKED, &req->flags); > if (!fpq->connected) { > - err = -ENODEV; > + err = fpq->aborted ? -ECONNABORTED : -ENODEV; > goto out_end; > } > if (err) { > @@ -2076,7 +2077,7 @@ static void end_polls(struct fuse_conn *fc) > * is OK, the request will in that case be removed from the list before we touch > * it. > */ > -void fuse_abort_conn(struct fuse_conn *fc) > +void fuse_abort_conn(struct fuse_conn *fc, int is_abort) > { > struct fuse_iqueue *fiq = &fc->iq; > > @@ -2095,6 +2096,7 @@ void fuse_abort_conn(struct fuse_conn *fc) > > spin_lock(&fpq->lock); > fpq->connected = 0; > + fpq->aborted = is_abort; > list_for_each_entry_safe(req, next, &fpq->io, list) { > req->out.h.error = -ECONNABORTED; > spin_lock(&req->waitq.lock); > @@ -2113,6 +2115,7 @@ void fuse_abort_conn(struct fuse_conn *fc) > > spin_lock(&fiq->waitq.lock); > fiq->connected = 0; > + fiq->aborted = is_abort; > list_splice_init(&fiq->pending, &to_end2); > list_for_each_entry(req, &to_end2, list) > clear_bit(FR_PENDING, &req->flags); > @@ -2151,7 +2154,7 @@ int fuse_dev_release(struct inode *inode, struct file *file) > /* Are we the last open device? */ > if (atomic_dec_and_test(&fc->dev_count)) { > WARN_ON(fc->iq.fasync != NULL); > - fuse_abort_conn(fc); > + fuse_abort_conn(fc, 0); > } > fuse_dev_free(fud); > } > diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h > index d5773ca67ad2..650e72be4174 100644 > --- a/fs/fuse/fuse_i.h > +++ b/fs/fuse/fuse_i.h > @@ -387,6 +387,9 @@ struct fuse_iqueue { > /** Connection established */ > unsigned connected; > > + /** Connection aborted via sysfs */ > + int aborted; > + Does it need to be a per-queue granularity? Isn't a single bool in fuse_conn sufficient? Thanks, Miklos > /** Readers of the connection are waiting on this */ > wait_queue_head_t waitq; > > @@ -414,6 +417,9 @@ struct fuse_pqueue { > /** Connection established */ > unsigned connected; > > + /** Connection aborted via sysfs */ > + int aborted; > + > /** Lock protecting accessess to members of this structure */ > spinlock_t lock; > > @@ -851,7 +857,7 @@ void fuse_request_send_background_locked(struct fuse_conn *fc, > struct fuse_req *req); > > /* Abort all requests */ > -void fuse_abort_conn(struct fuse_conn *fc); > +void fuse_abort_conn(struct fuse_conn *fc, int is_abort); > > /** > * Invalidate inode attributes > diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c > index 94a745acaef8..8cc9de4ec16d 100644 > --- a/fs/fuse/inode.c > +++ b/fs/fuse/inode.c > @@ -371,7 +371,7 @@ void fuse_unlock_inode(struct inode *inode) > > static void fuse_umount_begin(struct super_block *sb) > { > - fuse_abort_conn(get_fuse_conn_super(sb)); > + fuse_abort_conn(get_fuse_conn_super(sb), 0); > } > > static void fuse_send_destroy(struct fuse_conn *fc) > @@ -393,7 +393,7 @@ static void fuse_put_super(struct super_block *sb) > > fuse_send_destroy(fc); > > - fuse_abort_conn(fc); > + fuse_abort_conn(fc, 0); > mutex_lock(&fuse_mutex); > list_del(&fc->entry); > fuse_ctl_remove_conn(fc); > diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h > index 42fa977e3b14..4025a5599b2b 100644 > --- a/include/uapi/linux/fuse.h > +++ b/include/uapi/linux/fuse.h > @@ -112,6 +112,9 @@ > * 7.26 > * - add FUSE_HANDLE_KILLPRIV > * - add FUSE_POSIX_ACL > + * > + * 7.27 > + * - reading from /dev/fuse after sysfs abort returns -ECONNABORTED > */ > > #ifndef _LINUX_FUSE_H > @@ -147,7 +150,7 @@ > #define FUSE_KERNEL_VERSION 7 > > /** Minor version number of this interface */ > -#define FUSE_KERNEL_MINOR_VERSION 26 > +#define FUSE_KERNEL_MINOR_VERSION 27 > > /** The node ID of the root inode */ > #define FUSE_ROOT_ID 1 > -- > 2.15.0 >
