From: Joseph Qi <joseph.qi@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Cc: Mark Fasheh <mfasheh@xxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [4.0+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/aops.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN fs/ocfs2/aops.c~ocfs2-fix-shift-left-overflow fs/ocfs2/aops.c
--- a/fs/ocfs2/aops.c~ocfs2-fix-shift-left-overflow
+++ a/fs/ocfs2/aops.c
@@ -685,7 +685,7 @@ static int ocfs2_direct_IO_zero_extend(s
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(str
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);
_
--
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