| Message ID | 1476963342-26989-1-git-send-email-jack@suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Looks fine,
Reviewed-by: Christoph Hellwig <hch@lst.de>
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On Thu, Oct 20, 2016 at 01:35:42PM +0200, Jan Kara wrote: > iomap_page_mkwrite_actor() calls __block_write_begin_int() with position > masked as pos & ~PAGE_MASK which is equivalent to pos & (PAGE_SIZE-1). > Thus it masks off high bits of file position. However > __block_write_begin_int() expects full file position on input. This does > not cause any visible issues because all __block_write_begin_int() > really cares about are low file position bits but still it is a bug > waiting to happen. > > Signed-off-by: Jan Kara <jack@suse.cz> > --- > fs/iomap.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/fs/iomap.c b/fs/iomap.c > index 013d1d36fbbf..3341907eefc7 100644 > --- a/fs/iomap.c > +++ b/fs/iomap.c > @@ -433,8 +433,7 @@ iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, > struct page *page = data; > int ret; > > - ret = __block_write_begin_int(page, pos & ~PAGE_MASK, length, > - NULL, iomap); > + ret = __block_write_begin_int(page, pos, length, NULL, iomap); > if (ret) > return ret; Looks good. I've added it to my -rc3 fixes series. Cheers, Dave.
diff --git a/fs/iomap.c b/fs/iomap.c index 013d1d36fbbf..3341907eefc7 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -433,8 +433,7 @@ iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, struct page *page = data; int ret; - ret = __block_write_begin_int(page, pos & ~PAGE_MASK, length, - NULL, iomap); + ret = __block_write_begin_int(page, pos, length, NULL, iomap); if (ret) return ret;
iomap_page_mkwrite_actor() calls __block_write_begin_int() with position masked as pos & ~PAGE_MASK which is equivalent to pos & (PAGE_SIZE-1). Thus it masks off high bits of file position. However __block_write_begin_int() expects full file position on input. This does not cause any visible issues because all __block_write_begin_int() really cares about are low file position bits but still it is a bug waiting to happen. Signed-off-by: Jan Kara <jack@suse.cz> --- fs/iomap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)