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| author | Yongqiang Yang <xiaoqiangnk@gmail.com> | 2011-12-13 22:29:12 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-12-21 12:57:44 -0800 |
| commit | 5da4b53abb4424f4b502a37425ffe4e46a7df5b5 (patch) | |
| tree | ecf73db8f5d03b80b8c01fe02df468f990543372 | |
| parent | 8fe5e8ff93473129957c6d4a7df80046186b9c7b (diff) | |
ext4: handle EOF correctly in ext4_bio_write_page()
commit 5a0dc7365c240795bf190766eba7a27600be3b3e upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -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 bd6a85e33c9..d99d74aca8a 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -405,6 +405,18 @@ 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; |