Re: xfs_repair: add '-F' option to ignore writable mount checking

[Yang Joseph <joseph.yang@xtaotech.com>]

xfs_repair should not touch non-xfs mountpoints in platform_check_mount().
If non-xfs mountpoints can be filtered out, the dead fuse mountpoint can
never block our xfs_repair. The following patch can fix my problem and not
add dangerous option to xfs_repair.

thx,

Yang Honggang

-------------------------new patch----------------------
diff --git a/libxfs/linux.c b/libxfs/linux.c
index 0bace3e..6ad24ce 100644
--- a/libxfs/linux.c
+++ b/libxfs/linux.c
@@ -44,6 +44,7 @@ static int max_block_alignment;
  #endif

  #define PROC_MOUNTED   "/proc/mounts"
+#define MNTTYPE_XFS        "xfs"

  /*
   * Check if the filesystem is mounted.  Be verbose if asked, and
@@ -78,6 +79,9 @@ platform_check_mount(char *name, char *block, struct 
stat *s, int flags)
                 return 1;
         }
         while ((mnt = getmntent(f)) != NULL) {
+               /* filter out non xfs mountpoint */
+               if (strncmp(mnt->mnt_type, MNTTYPE_XFS, 
strlen(mnt->mnt_type)))
+                       continue;
                 if (stat(mnt->mnt_dir, &mst) < 0)
                         continue;
                 if (mst.st_dev != s->st_rdev)
-------------------------new patch end-----------------

On 02/25/2018 06:04 AM, Dave Chinner wrote:
> On Sat, Feb 24, 2018 at 11:56:44AM -0600, Eric Sandeen wrote:
>> On 2/24/18 5:23 AM, Yang Joseph wrote:
>>> hello,
>>>
>>> Before the repair process, xfs_repair will check if user specified device already
>>> has a writable mountpoint. And it will stat all the mountpoints of the system. If there
>>> is a dead mountpoint, this checking will be blocked and xfs_repair will enter 'D' state.
> So why is the mount point dead?
>
> That kinda means that the filesystem is still mounted, but something
> has hung somewhere and the filesystem may still have active
> references to the underlying device and be doing stuff that is
> modifying the filesystem....
>
> And if the device is still busy, then you aren't going to be able to
> mount the repaired device, anyway, because the block device is still
> busy...
>
>> That sounds like a bug worth fixing, but I am much
>> less excited about adding options which could do serious damage
>> to a filesystem.
> TO me it sounds like something that should be fixed by a reboot, not
> by adding dangerous options to xfs_repair...
>
> Cheers,
>
> Dave.