On Wed, Jul 01, 2009 at 03:16:15PM +0530, Aneesh Kumar K.V wrote: > block_write_full_page consider a zero return from get_block as success. > noalloc_get_block_write returned zero even if we failed to find a mapping > blocks. Returning non zero ensures we fallback to the error handling path > of block_write_full_page which would properly redirty the page after > the below patch is applied. > > http://article.gmane.org/gmane.linux.file-systems/33145 > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> > --- > > NOTE: I am not sure whether -EGAIN is the right error to be returned error. > This patch should enable us to push the pending ext4 patches in the patch > queue without depending on the full series from Jan. Will reply to this > email with patch ordering. > > fs/ext4/inode.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 25638bc..6c814af 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -2514,7 +2514,10 @@ static int noalloc_get_block_write(struct inode *inode, sector_t iblock, > if (ret > 0) { > bh_result->b_size = (ret << inode->i_blkbits); > ret = 0; > - } > + } else if (create && ret == 0) > + /* write request on unmapped buffer head. */ > + ret = -EAGAIN; > + > return ret; > } > The patch ordering I tested this with was + stable-boundary + stable-boundary-undo.patch + jan-kara-dont-clear-dirty-bits-in-block_write_full_page + dont-look-at-buffer_heads-outside-i_size + fix-mmap-truncate-race-with-subpage-blocksize + 01.patch <=============================================== This is the above patch + fix-mmap-truncate-race-with-nondelalloc + move-__ext4_journaled-writepage-function + add-WARN_ON-with-unmapped-dirty-bh-in-writepage + vfs-jan-kara-page_mkwrite-infrastructure + allocate-blocks-correctly-with-subpage-blocksize > jan-kara-unmap-underlying-metadata-of-new-buffers-only-when-mapped Now with jan-kara-dont-clear-dirty-bits-in-block_write_full_page block_write_full_page will redirty the page when get_block fails. That would ensure that we don't drop the pages if we find unmapped buffer_heads in the writepage callback. The patch fix-mmap-truncate-race-with-subpage-blocksize actually pass pages with unmapped buffer heads to block_write_full_page. This also means we can push patches upto move-__ext4_journaled-writepage-function to upstream in 2.6.31 I am yet to run the full patch set on ABAT. So the patches had limited testing. -aneesh -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
