Commit 32e5a2a2 authored Aug 06, 2015 by Joseph Qi Committed by Linus Torvalds Aug 07, 2015

ocfs2: fix shift left overflow



When using a large volume, for example 9T volume with 2T already used,
frequent creation of small files with O_DIRECT when the IO is not
cluster aligned may clear sectors in the wrong place.  This will cause
filesystem corruption.

This is because p_cpos is a u32.  When calculating the corresponding
sector it should be converted to u64 first, otherwise it may overflow.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 18896451

fs/ocfs2/aops.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -685,7 +685,7 @@ static int ocfs2_direct_IO_zero_extend(struct ocfs2_super *osb,

		if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {
		u64 s = i_size_read(inode);
		sector_t sector = (p_cpos << (osb->s_clustersize_bits - 9)) +
		sector_t sector = ((u64)p_cpos << (osb->s_clustersize_bits - 9)) +
		(do_div(s, osb->s_clustersize) >> 9);

		ret = blkdev_issue_zeroout(osb->sb->s_bdev, sector,
		@@ -910,7 +910,7 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb,
		BUG_ON(!p_cpos \|\| (ext_flags & OCFS2_EXT_UNWRITTEN));

		ret = blkdev_issue_zeroout(osb->sb->s_bdev,
		p_cpos << (osb->s_clustersize_bits - 9),
		(u64)p_cpos << (osb->s_clustersize_bits - 9),
		zero_len_head >> 9, GFP_NOFS, false);
		if (ret < 0)
		mlog_errno(ret);