Prevent create IMSM volume with size smaller than 1M or chunk

Block creation of the imsm volume when given size is smaller than 1M and
print appropriate message.

Commit b53bfba6119d3f6f56eb9e10e5a59da6901af159
(imsm: use rounded size for metadata initialization) introduces issue with
rounding volume sizes smaller than 1M to 0. There is an inconsistency when
size smaller than 1M was given depends of what we give as target device:
1) When block devices was given created volume has maximum available size.
2) When container symlink was given created volume has size 0. Additionally
it causes below call trace:

[69587.891556] WARNING: CPU: 28 PID: 22485 at ../drivers/md/md.c:7582 md_seq_show+0x764/0x770 [md_mod]
[69588.066405] Call Trace:
[69588.066409]  seq_read+0x336/0x430
[69588.066411]  proc_reg_read+0x40/0x70
[69588.066412]  __vfs_read+0x26/0x140
[69588.066414]  vfs_read+0x89/0x130
[69588.066415]  SyS_read+0x42/0x90
[69588.066417]  do_syscall_64+0x74/0x140
[69588.066419]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Signed-off-by: Roman Sobanski <roman.sobanski@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

diff --git a/super-intel.c b/super-intel.c
index c55c85f1b0f9d316c8d0cf966d1bda7ae4a16869..520abf5df808e523a93852cebd79e71ecd290ac5 100644 (file)
--- a/super-intel.c
+++ b/super-intel.c
@@ -7358,6 +7358,16 @@ static int validate_geometry_imsm(struct supertype *st, int level, int layout,
                                                        verbose);
        }
 
+       if (size && ((size < 1024) || (*chunk != UnSet &&
+           size < (unsigned long long) *chunk))) {
+               pr_err("Given size must be greater than 1M and chunk size.\n");
+               /* Depends on algorithm in Create.c :
+                * if container was given (dev == NULL) return -1,
+                * if block device was given ( dev != NULL) return 0.
+                */
+               return dev ? -1 : 0;
+       }
+
        if (!dev) {
                if (st->sb) {
                        struct intel_super *super = st->sb;