Re: [PATCH] btrfs: add missing check for nocow and compression inode flags

10 Jul 2020


      On 10/07/2020 12:06, David Sterba wrote:
...
+static int check_fsflags(unsigned int old_flags, unsigned int flags)
 {
   if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
   	      FS_NOATIME_FL | FS_NODUMP_FL | \
@@ -174,9 +177,19 @@ static int check_fsflags(unsigned int flags)
   	      FS_NOCOW_FL))
   	return -EOPNOTSUPP;

/* COMPR and NOCOMP on new/old are valid */
if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
return -EINVAL;


if ((flags & FS_COMPR_FL) && (flags & FS_NOCOW_FL))
return -EINVAL;



/* NOCOW and compression options are mutually exclusive */
if ((old_flags & FS_NOCOW_FL) && (flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
return -EINVAL;


if ((flags & FS_NOCOW_FL) && (old_flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
return -EINVAL;




If we'd pass in fs_info to check_fsflags() we could also validate against mount options
which are incompatible with inode flags. Like -o nodatacow and FS_COMPR_FL or 
-o auth_key and FS_NOCOW_FL.

    