fuse: allow private mappings of "direct_io" files
Allow MAP_PRIVATE mmaps of "direct_io" files. This is necessary for
execute support.
MAP_SHARED mappings require some sort of coherency between the
underlying file and the mapping. With "direct_io" it is difficult to
provide this, so for the moment just disallow shared (read-write and
read-only) mappings altogether.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 78a2c83..2b25133 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1292,6 +1292,15 @@
return 0;
}
+static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ /* Can't provide the coherency needed for MAP_SHARED */
+ if (vma->vm_flags & VM_MAYSHARE)
+ return -ENODEV;
+
+ return generic_file_mmap(file, vma);
+}
+
static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
struct file_lock *fl)
{
@@ -1926,6 +1935,7 @@
.llseek = fuse_file_llseek,
.read = fuse_direct_read,
.write = fuse_direct_write,
+ .mmap = fuse_direct_mmap,
.open = fuse_open,
.flush = fuse_flush,
.release = fuse_release,
@@ -1935,7 +1945,7 @@
.unlocked_ioctl = fuse_file_ioctl,
.compat_ioctl = fuse_file_compat_ioctl,
.poll = fuse_file_poll,
- /* no mmap and splice_read */
+ /* no splice_read */
};
static const struct address_space_operations fuse_file_aops = {