Commit b9b4bb26 authored Jun 24, 2016 by Anthony Romano Committed by Linus Torvalds Jun 24, 2016

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: 1635f6a7 ("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>

parent a7b50abc

mm/shmem.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

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