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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 12:58:34 -0800 |
| commit | 91bcbb691f0dfe96fe385ba174fc3966049733ae (patch) | |
| tree | 319cb06cb70ed4941dcecb93897eaad6790bea4e /fs | |
| parent | 8afe1f656c3cb0eff4219e3a4a22b95579148ad6 (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>
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 92f38ee13f8a..78ab854f2f90 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -401,6 +401,18 @@ 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; |