Commits
![OGAWA Hirofumi](https://secure.gravatar.com/avatar/8c0e976dc5fbad5088ca748febf17f70.jpg?s=96&d=mm)
OGAWA Hirofumi committed 07bfa4415ab
fat: work around race with userspace's read via blockdev while mounting If userspace reads the buffer via blockdev while mounting, sb_getblk()+modify can race with buffer read via blockdev. For example, FS userspace bh = sb_getblk() modify bh->b_data read ll_rw_block(bh) fill bh->b_data by on-disk data /* lost modified data by FS */ set_buffer_uptodate(bh) set_buffer_uptodate(bh) Userspace should not use the blockdev while mounting though, the udev seems to be already doing this. Although I think the udev should try to avoid this, workaround the race by small overhead. Link: http://lkml.kernel.org/r/87pnk7l3sw.fsf_-_@mail.parknet.co.jp Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Reported-by: Jan Stancek <jstancek@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>