[PATCH RESEND 4/5] cachefiles: correct the return value of cachefiles_check_volume_xattr()

[libaokun at huaweicloud.com]

From: Baokun Li <libaokun1 at huawei.com>

In cachefiles_check_volume_xattr(), the error returned by vfs_getxattr is
not passed to ret, so it ends up returning -ESTALE, which leads to an
endless loop as follows:

cachefiles_acquire_volume
retry:
  cachefiles_check_volume_xattr
  // return -ESTALE
  cachefiles_bury_object
  //  EIO causes rename failure
  goto retry;

So pass the error code to ret when xlen < 0 to avoid the above problem.

Fixes: 32e150037dce ("fscache, cachefiles: Store the volume coherency data")
Signed-off-by: Baokun Li <libaokun1 at huawei.com>
---
 fs/cachefiles/xattr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
index bcb6173943ee..20e4a4391090 100644
--- a/fs/cachefiles/xattr.c
+++ b/fs/cachefiles/xattr.c
@@ -252,6 +252,7 @@ int cachefiles_check_volume_xattr(struct cachefiles_volume *volume)
 		xlen = vfs_getxattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache, buf, len);
 	if (xlen != len) {
 		if (xlen < 0) {
+			ret = xlen;
 			trace_cachefiles_vfs_error(NULL, d_inode(dentry), xlen,
 						   cachefiles_trace_getxattr_error);
 			if (xlen == -EIO)
-- 
2.39.2