diff options
| author |   Jan Kara <jack@suse.cz> | 2013-01-28 20:53:28 -0500 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2013-01-28 20:53:28 -0500 |
| commit | 8a850c3fb8d0f204eabc1a32b502f47d3c16eac4 (patch) | |
| tree | 7178b6117c8d559e4de519bfc17e792f6456bdd8 /fs/ext4/page-io.c | |
| parent | ext4: simplify mpage_add_bh_to_extent() (diff) | |
| download | linux-dev-8a850c3fb8d0f204eabc1a32b502f47d3c16eac4.tar.xz linux-dev-8a850c3fb8d0f204eabc1a32b502f47d3c16eac4.zip | |
ext4: Make ext4_bio_writepage() handle unprepared buffers
So far ext4_bio_writepage() unconditionally cleared dirty bit on all
buffers underlying the page. That implicitely assumes we can write all
buffers. So far that is true because callers call into
ext4_bio_writepage() make sure all buffers in the page are mapped but:
a) it's a data corruption bug waiting to happen
b) in data=ordered mode when blocksize < pagesize we do need to write
pages that may have only some of dirty buffers mapped.
So change ext4_bio_writepage() to skip buffers that cannot be written without
clearing their dirty bit.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/page-io.c')
| -rw-r--r-- | fs/ext4/page-io.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 3fb385cd9670..0290bf85f97e 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -350,14 +350,6 @@ static int io_submit_add_bh(struct ext4_io_submit *io, unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); } - if (!buffer_mapped(bh) || buffer_delay(bh)) { - if (!buffer_mapped(bh)) - clear_buffer_dirty(bh); - if (io->io_bio) - ext4_io_submit(io); - return 0; - } - if (io->io_bio && bh->b_blocknr != io->io_next_block) { submit_and_retry: ext4_io_submit(io); @@ -436,6 +428,15 @@ int ext4_bio_write_page(struct ext4_io_submit *io, set_buffer_uptodate(bh); continue; } + if (!buffer_dirty(bh) || buffer_delay(bh) || + !buffer_mapped(bh) || buffer_unwritten(bh)) { + /* A hole? We can safely clear the dirty bit */ + if (!buffer_mapped(bh)) + clear_buffer_dirty(bh); + if (io->io_bio) + ext4_io_submit(io); + continue; + } ret = io_submit_add_bh(io, io_page, inode, wbc, bh); if (ret) { /* |