fuse: readdirplus: fix RCU walk

[mirror_ubuntu-bionic-kernel.git] / fs / fuse / dir.c

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 9b16806f11dad2e296b5864455c8f47e6998bb94..a75159846a75b8ddf335dcea0a118c6641920844 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -182,6 +182,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
        struct inode *inode;
        struct dentry *parent;
        struct fuse_conn *fc;
+       struct fuse_inode *fi;
        int ret;
 
        inode = ACCESS_ONCE(entry->d_inode);
@@ -228,7 +229,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
                if (!err && !outarg.nodeid)
                        err = -ENOENT;
                if (!err) {
-                       struct fuse_inode *fi = get_fuse_inode(inode);
+                       fi = get_fuse_inode(inode);
                        if (outarg.nodeid != get_node_id(inode)) {
                                fuse_queue_forget(fc, forget, outarg.nodeid, 1);
                                goto invalid;
@@ -246,8 +247,11 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
                                       attr_version);
                fuse_change_entry_timeout(entry, &outarg);
        } else if (inode) {
-               fc = get_fuse_conn(inode);
-               if (fc->readdirplus_auto) {
+               fi = get_fuse_inode(inode);
+               if (flags & LOOKUP_RCU) {
+                       if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
+                               return -ECHILD;
+               } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
                        parent = dget_parent(entry);
                        fuse_advise_use_readdirplus(parent->d_inode);
                        dput(parent);
@@ -1292,6 +1296,8 @@ static int fuse_direntplus_link(struct file *file,
        }
 
 found:
+       if (fc->readdirplus_auto)
+               set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
        fuse_change_entry_timeout(dentry, o);
 
        err = 0;