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Commit faa35ed7 authored by Anthony Romano's avatar Anthony Romano Committed by Sasha Levin
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tmpfs: don't undo fallocate past its last page 

[ Upstream commit b9b4bb26af017dbe930cd4df7f9b2fc3a0497bfe ]

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: default avatarAnthony 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 4c2b0216

mm/shmem.c

+1 −1
Original line number Diff line number Diff line
@@ -2142,7 +2142,7 @@ 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_CACHE_SHIFT,

				(loff_t)index << PAGE_CACHE_SHIFT, true);

				((loff_t)index << PAGE_CACHE_SHIFT) - 1, true);

			goto undone;

		}