On Thu, Aug 21, 2014 at 6:09 PM, Maxim Patlasov <mpatla...@parallels.com> wrote: > The patch enables the feature by passing 'true' to fuse_file_put in > fuse_release_common. > > Previously, this was safe only in special cases when we sure that > multi-threaded userspace won't deadlock if we'll synchronously send > FUSE_RELEASE in the context of read-ahead or write-back callback. Now, it's > always safe because callbacks don't send requests to userspace anymore.
But we do want to make this privileged, as there are unlikely but possible DoS scenarios with a sync release. Thanks, Miklos > > Signed-off-by: Maxim Patlasov <mpatla...@parallels.com> > --- > fs/fuse/file.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/fuse/file.c b/fs/fuse/file.c > index 73bce1b..cd55488 100644 > --- a/fs/fuse/file.c > +++ b/fs/fuse/file.c > @@ -333,7 +333,8 @@ void fuse_release_common(struct file *file, int opcode) > * synchronous RELEASE is allowed (and desirable) in this case > * because the server can be trusted not to screw up. > */ > - fuse_file_put(ff, ff->fc->destroy_req != NULL); > + fuse_file_put(ff, ff->fc->destroy_req != NULL || > + must_release_synchronously(ff)); > } > > static int fuse_open(struct inode *inode, struct file *file) > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
