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Index: sys/fs/fuse/fuse_vnops.c
===================================================================
--- sys/fs/fuse/fuse_vnops.c
+++ sys/fs/fuse/fuse_vnops.c
@@ -2225,6 +2225,20 @@
}
/*
+ * List extended attributes
+ *
+ * The FUSE_LISTXATTR operation is based on Linux's listxattr(2) syscall, which
+ * has a number of differences compared to its FreeBSD equivalent,
+ * extattr_list_file:
+ *
+ * - FUSE_LISTXATTR returns all extended attributes across all namespaces,
+ * whereas listxattr(2) only returns attributes for a single namespace
+ * - FUSE_LISTXATTR prepends each attribute name with "namespace."
+ * - If the provided buffer is not large enough to hold the result,
+ * FUSE_LISTXATTR should return ERANGE, whereas listxattr is expected to
+ * return as many results as will fit.
+ */
+/*
struct vop_listextattr_args {
struct vop_generic_args a_gen;
struct vnode *a_vp;
@@ -2303,14 +2317,31 @@
*/
fdisp_refresh_vp(&fdi, FUSE_LISTXATTR, vp, td, cred);
list_xattr_in = fdi.indata;
- list_xattr_in->size = linux_list_len + sizeof(*list_xattr_out);
+ list_xattr_in->size = linux_list_len;
err = fdisp_wait_answ(&fdi);
- if (err != 0)
+ if (err == ERANGE) {
+ /*
+ * Race detected. The attribute list must've grown since the
+ * first FUSE_LISTXATTR call. Start over. Go all the way back
+ * to userland so we can process signals, if necessary, before
+ * restarting.
+ */
+ err = ERESTART;
goto out;
+ } else if (err != 0)
+ goto out;
linux_list = fdi.answ;
- linux_list_len = fdi.iosize;
+ /* FUSE doesn't allow the server to return more data than requested */
+ if (fdi.iosize > linux_list_len) {
+ printf("WARNING: FUSE protocol violation. Server returned "
+ "more extended attribute data than requested; "
+ "should've returned ERANGE instead");
+ } else {
+ /* But returning less data is fine */
+ linux_list_len = fdi.iosize;
+ }
/*
* Retrieve the BSD compatible list values.

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