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| author | Yongqiang Yang <xiaoqiangnk@gmail.com> | 2011-12-13 22:29:12 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-12-13 22:29:12 -0500 |
| commit | 5a0dc7365c240795bf190766eba7a27600be3b3e (patch) | |
| tree | 614d5275640f4df89604f64e2cd47a438644226e /fs | |
| parent | 5b5ffa49d4bbb8ca4c41c094261660264f16bd20 (diff) | |
| download | linux-5a0dc7365c240795bf190766eba7a27600be3b3e.tar.bz2 | |
ext4: handle EOF correctly in ext4_bio_write_page()
We need to zero out part of a page which beyond EOF before setting uptodate,
otherwise, mapread or write will see non-zero data beyond EOF.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/page-io.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 7ce1d0b19c94..7e106c810c62 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -385,6 +385,18 @@ int ext4_bio_write_page(struct ext4_io_submit *io, block_end = block_start + blocksize; if (block_start >= len) { + /* + * Comments copied from block_write_full_page_endio: + * + * The page straddles i_size. It must be zeroed out on + * each and every writepage invocation because it may + * be mmapped. "A file is mapped in multiples of the + * page size. For a file that is not a multiple of + * the page size, the remaining memory is zeroed when + * mapped, and writes to that region are not written + * out to the file." + */ + zero_user_segment(page, block_start, block_end); clear_buffer_dirty(bh); set_buffer_uptodate(bh); continue; |