f2fs: fix defragment writeback range truncation on 32-bit

f2fs_defragment_range() flushes the range it is about to defragment:

	filemap_write_and_wait_range(inode->i_mapping,
				pg_start << PAGE_SHIFT,
				(pg_end << PAGE_SHIFT) - 1);

pg_start and pg_end are pgoff_t, 32 bits on 32-bit kernels, so both
shifts are evaluated in 32 bits and truncated before they are widened to
the loff_t parameters.  pg_end is only capped by the file's page count,
so for a file larger than 4 GiB the shift wraps.

For a 5 GiB file pg_end is 1310720 and the range collapses from
[0, 5 GiB) to [0, 1 GiB), leaving the rest of the dirty pages unwritten
before the blocks are moved.  For 8 GiB the shift yields 0, the minus one
makes it (loff_t)-1, and the range becomes [0, LLONG_MAX].

The matching call in f2fs_collapse_range() already casts:

	filemap_write_and_wait_range(inode->i_mapping,
				(loff_t)index << PAGE_SHIFT,
				((loff_t)pg_end << PAGE_SHIFT) - 1);

Do the same here.  On i386 the shift changes from "shl $0xc,%ecx" to
"shld", i.e. from a 32-bit shift to a double-precision one.

Cc: stable@kernel.org
Fixes: d323d005ac4a ("f2fs: support file defragment")
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

0 files changed, 0 insertions, 0 deletions