From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 31 May 2018 09:49:47 -0400 From: Brian Foster To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 18/18] xfs: allow writeback on pages without buffer heads Message-ID: <20180531134946.GL2997@bfoster.bfoster> References: <20180530100013.31358-1-hch@lst.de> <20180530100013.31358-19-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180530100013.31358-19-hch@lst.de> Sender: owner-linux-mm@kvack.org List-ID: On Wed, May 30, 2018 at 12:00:13PM +0200, Christoph Hellwig wrote: > Disable the IOMAP_F_BUFFER_HEAD flag on file systems with a block size > equal to the page size, and deal with pages without buffer heads in > writeback. Thanks to the previous refactoring this is basically trivial > now. > > Signed-off-by: Christoph Hellwig > --- Reviewed-by: Brian Foster > fs/xfs/xfs_aops.c | 47 +++++++++++++++++++++++++++++++++------------- > fs/xfs/xfs_iomap.c | 3 ++- > 2 files changed, 36 insertions(+), 14 deletions(-) > > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index 84f88cecd2f1..6640377b6eae 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -91,6 +91,19 @@ xfs_find_daxdev_for_inode( > return mp->m_ddev_targp->bt_daxdev; > } > > +static void > +xfs_finish_page_writeback( > + struct inode *inode, > + struct bio_vec *bvec, > + int error) > +{ > + if (error) { > + SetPageError(bvec->bv_page); > + mapping_set_error(inode->i_mapping, -EIO); > + } > + end_page_writeback(bvec->bv_page); > +} > + > /* > * We're now finished for good with this page. Update the page state via the > * associated buffer_heads, paying attention to the start and end offsets that > @@ -103,7 +116,7 @@ xfs_find_daxdev_for_inode( > * and buffers potentially freed after every call to end_buffer_async_write. > */ > static void > -xfs_finish_page_writeback( > +xfs_finish_buffer_writeback( > struct inode *inode, > struct bio_vec *bvec, > int error) > @@ -178,9 +191,12 @@ xfs_destroy_ioend( > next = bio->bi_private; > > /* walk each page on bio, ending page IO on them */ > - bio_for_each_segment_all(bvec, bio, i) > - xfs_finish_page_writeback(inode, bvec, error); > - > + bio_for_each_segment_all(bvec, bio, i) { > + if (page_has_buffers(bvec->bv_page)) > + xfs_finish_buffer_writeback(inode, bvec, error); > + else > + xfs_finish_page_writeback(inode, bvec, error); > + } > bio_put(bio); > } > > @@ -782,13 +798,16 @@ xfs_writepage_map( > { > LIST_HEAD(submit_list); > struct xfs_ioend *ioend, *next; > - struct buffer_head *bh; > + struct buffer_head *bh = NULL; > ssize_t len = i_blocksize(inode); > int error = 0; > int count = 0; > loff_t file_offset; /* file offset of page */ > unsigned poffset; /* offset into page */ > > + if (page_has_buffers(page)) > + bh = page_buffers(page); > + > /* > * Walk the blocks on the page, and we we run off then end of the > * current map or find the current map invalid, grab a new one. > @@ -797,11 +816,9 @@ xfs_writepage_map( > * replace the bufferhead with some other state tracking mechanism in > * future. > */ > - file_offset = page_offset(page); > - bh = page_buffers(page); > - for (poffset = 0; > + for (poffset = 0, file_offset = page_offset(page); > poffset < PAGE_SIZE; > - poffset += len, file_offset += len, bh = bh->b_this_page) { > + poffset += len, file_offset += len) { > /* past the range we are writing, so nothing more to write. */ > if (file_offset >= end_offset) > break; > @@ -809,9 +826,10 @@ xfs_writepage_map( > /* > * Block does not contain valid data, skip it. > */ > - if (!buffer_uptodate(bh)) { > + if (bh && !buffer_uptodate(bh)) { > if (PageUptodate(page)) > ASSERT(buffer_mapped(bh)); > + bh = bh->b_this_page; > continue; > } > > @@ -836,10 +854,15 @@ xfs_writepage_map( > * meaningless for holes (!mapped && uptodate), so check we did > * have a buffer covering a hole here and continue. > */ > + if (bh) > + bh = bh->b_this_page; > continue; > } > > - xfs_map_at_offset(inode, bh, &wpc->imap, file_offset); > + if (bh) { > + xfs_map_at_offset(inode, bh, &wpc->imap, file_offset); > + bh = bh->b_this_page; > + } > xfs_add_to_ioend(inode, file_offset, page, wpc, wbc, > &submit_list); > count++; > @@ -939,8 +962,6 @@ xfs_do_writepage( > > trace_xfs_writepage(inode, page, 0, 0); > > - ASSERT(page_has_buffers(page)); > - > /* > * Refuse to write the page out if we are called from reclaim context. > * > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > index f949f0dd7382..93c40da3378a 100644 > --- a/fs/xfs/xfs_iomap.c > +++ b/fs/xfs/xfs_iomap.c > @@ -1031,7 +1031,8 @@ xfs_file_iomap_begin( > if (XFS_FORCED_SHUTDOWN(mp)) > return -EIO; > > - iomap->flags |= IOMAP_F_BUFFER_HEAD; > + if (i_blocksize(inode) < PAGE_SIZE) > + iomap->flags |= IOMAP_F_BUFFER_HEAD; > > if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) && > !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) { > -- > 2.17.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html