fuse: truncate pending writes on O_TRUNC
Make sure cached writes are not reordered around open(..., O_TRUNC), with
the obvious wrong results.
Fixes: 4d99ff8f12eb ("fuse: Turn writeback cache on")
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 0f022568..6edf949 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -217,7 +217,7 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
{
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
- bool lock_inode = (file->f_flags & O_TRUNC) &&
+ bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
fc->atomic_o_trunc &&
fc->writeback_cache;
@@ -225,16 +225,20 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
if (err)
return err;
- if (lock_inode)
+ if (is_wb_truncate) {
inode_lock(inode);
+ fuse_set_nowrite(inode);
+ }
err = fuse_do_open(fc, get_node_id(inode), file, isdir);
if (!err)
fuse_finish_open(inode, file);
- if (lock_inode)
+ if (is_wb_truncate) {
+ fuse_release_nowrite(inode);
inode_unlock(inode);
+ }
return err;
}
