tmpfs: don't undo fallocate past its last page

When fallocate is interrupted it will undo a range that extends one byte
past its range of allocated pages.  This can corrupt an in-use page by
zeroing out its first byte.  Instead, undo using the inclusive byte
range.

Fixes: 1635f6a741 ("tmpfs: undo fallocation on failure")
Link: http://lkml.kernel.org/r/1462713387-16724-1-git-send-email-anthony.romano@coreos.com
Signed-off-by: Anthony Romano <anthony.romano@coreos.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Brandon Philips <brandon@ifup.co>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Anthony Romano 2016-06-24 14:48:43 -07:00 committed by Linus Torvalds
parent a7b50abc90
commit b9b4bb26af

View File

@ -2227,7 +2227,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
/* Remove the !PageUptodate pages we added */
shmem_undo_range(inode,
(loff_t)start << PAGE_SHIFT,
(loff_t)index << PAGE_SHIFT, true);
((loff_t)index << PAGE_SHIFT) - 1, true);
goto undone;
}