xfs: check for dinode realtime flag corruption
xfs: check for dinode realtime flag corruption

Ramon tested XFS with a modified version of fsfuzzer and hit a NULL
pointer dereference in __xfs_get_blocks due to the RT device target
pointer being NULL.

To fix this reject inode with the realtime bit set on a a filesystem
without an RT subvolume during inode read.

Signed-off-by: Christoph Hellwig <923f7720577207a44b32e59bbfbea59d27f1ae8e@lst.de>
Reviewed-by: Eric Sandeen <d55521028c14e0f378be5444e4ea388161c0d7e7@sandeen.net>
Reviewed-by: Felix Blyakher <489795e92d328beb2187b977cd7059f2eaf90933@sgi.com>
Reported-by: Ramon de Carvalho Valle <2bfe2630cd649d2b7fecaff845d0a28fb600f4a0@risesecurity.org>
Tested-by: Ramon de Carvalho Valle <2bfe2630cd649d2b7fecaff845d0a28fb600f4a0@risesecurity.org>
Signed-off-by: Felix Blyakher <489795e92d328beb2187b977cd7059f2eaf90933@sgi.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas