On Mon, Jun 01, 2015 at 08:52:37PM +0530, Chandan Rajendra wrote: > For the subpagesize-blocksize scenario, a page can contain multiple > blocks. In such cases, this patch handles writing data to files. > > Also, When setting EXTENT_DELALLOC, we no longer set EXTENT_UPTODATE bit on > the extent_io_tree since uptodate status is being tracked by the bitmap > pointed to by page->private.
To be honestly, I'm not sure why we set EXTENT_UPTODATE bit for data as we don't check for that bit at all for now, correct me if I'm wrong. > > Signed-off-by: Chandan Rajendra <[email protected]> > --- > fs/btrfs/extent_io.c | 141 > +++++++++++++++++++++++---------------------------- > fs/btrfs/file.c | 16 ++++++ > fs/btrfs/inode.c | 58 ++++++++++++++++----- > 3 files changed, 125 insertions(+), 90 deletions(-) > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index d37badb..3736ab5 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -1283,9 +1283,8 @@ int clear_extent_bits(struct extent_io_tree *tree, u64 > start, u64 end, > int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end, > struct extent_state **cached_state, gfp_t mask) > { > - return set_extent_bit(tree, start, end, > - EXTENT_DELALLOC | EXTENT_UPTODATE, > - NULL, cached_state, mask); > + return set_extent_bit(tree, start, end, EXTENT_DELALLOC, > + NULL, cached_state, mask); > } > > int set_extent_defrag(struct extent_io_tree *tree, u64 start, u64 end, > @@ -1498,25 +1497,6 @@ int extent_range_redirty_for_io(struct inode *inode, > u64 start, u64 end) > return 0; > } > > -/* > - * helper function to set both pages and extents in the tree writeback > - */ > -static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 > end) > -{ > - unsigned long index = start >> PAGE_CACHE_SHIFT; > - unsigned long end_index = end >> PAGE_CACHE_SHIFT; > - struct page *page; > - > - while (index <= end_index) { > - page = find_get_page(tree->mapping, index); > - BUG_ON(!page); /* Pages should be in the extent_io_tree */ > - set_page_writeback(page); > - page_cache_release(page); > - index++; > - } > - return 0; > -} > - > /* find the first state struct with 'bits' set after 'start', and > * return it. tree->lock must be held. NULL will returned if > * nothing was found after 'start' > @@ -2080,6 +2060,14 @@ static int page_read_complete(struct page *page) > return !test_page_blks_state(page, BLK_STATE_IO, start, end, 0); > } > > +static int page_write_complete(struct page *page) > +{ > + u64 start = page_offset(page); > + u64 end = start + PAGE_CACHE_SIZE - 1; > + > + return !test_page_blks_state(page, BLK_STATE_IO, start, end, 0); > +} > + > int free_io_failure(struct inode *inode, struct io_failure_record *rec) > { > int ret; > @@ -2575,38 +2563,37 @@ int end_extent_writepage(struct page *page, int err, > u64 start, u64 end) > */ > static void end_bio_extent_writepage(struct bio *bio, int err) > { > + struct btrfs_page_private *pg_private; > struct bio_vec *bvec; > + unsigned long flags; > u64 start; > u64 end; > + int clear_writeback; > int i; > > bio_for_each_segment_all(bvec, bio, i) { > struct page *page = bvec->bv_page; > > - /* We always issue full-page reads, but if some block > - * in a page fails to read, blk_update_request() will > - * advance bv_offset and adjust bv_len to compensate. > - * Print a warning for nonzero offsets, and an error > - * if they don't add up to a full page. */ > - if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) { > - if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE) > - > btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info, > - "partial page write in btrfs with offset %u > and length %u", > - bvec->bv_offset, bvec->bv_len); > - else > - > btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info, > - "incomplete page write in btrfs with offset > %u and " > - "length %u", > - bvec->bv_offset, bvec->bv_len); > - } > + start = page_offset(page) + bvec->bv_offset; > + end = start + bvec->bv_len - 1; > > - start = page_offset(page); > - end = start + bvec->bv_offset + bvec->bv_len - 1; > + pg_private = (struct btrfs_page_private *)page->private; > + > + spin_lock_irqsave(&pg_private->io_lock, flags); > > - if (end_extent_writepage(page, err, start, end)) > + if (end_extent_writepage(page, err, start, end)) { > + spin_unlock_irqrestore(&pg_private->io_lock, flags); > continue; > + } > > - end_page_writeback(page); > + clear_page_blks_state(page, 1 << BLK_STATE_IO, start, end); > + > + clear_writeback = page_write_complete(page); > + > + spin_unlock_irqrestore(&pg_private->io_lock, flags); > + > + if (clear_writeback) > + end_page_writeback(page); > } > > bio_put(bio); > @@ -3417,10 +3404,9 @@ static noinline_for_stack int > __extent_writepage_io(struct inode *inode, > u64 block_start; > u64 iosize; > sector_t sector; > - struct extent_state *cached_state = NULL; > struct extent_map *em; > struct block_device *bdev; > - size_t pg_offset = 0; > + size_t pg_offset; > size_t blocksize; > int ret = 0; > int nr = 0; > @@ -3467,8 +3453,16 @@ static noinline_for_stack int > __extent_writepage_io(struct inode *inode, > page_end, NULL, 1); > break; > } > - em = epd->get_extent(inode, page, pg_offset, cur, > - end - cur + 1, 1); > + > + pg_offset = cur & (PAGE_CACHE_SIZE - 1); > + > + if (!test_page_blks_state(page, BLK_STATE_DIRTY, cur, > + cur + blocksize - 1, 1)) { > + cur += blocksize; > + continue; > + } If we don't check this, the below get_extent() will return a HOLE (block_start == EXTENT_MAP_HOLE) and we can still go on to the next block, then we don't need to maintain this BLK_STATE_DIRTY bit all the while. > + > + em = epd->get_extent(inode, page, pg_offset, cur, blocksize, 1); > if (IS_ERR_OR_NULL(em)) { > SetPageError(page); > ret = PTR_ERR_OR_ZERO(em); > @@ -3479,7 +3473,7 @@ static noinline_for_stack int > __extent_writepage_io(struct inode *inode, > em_end = extent_map_end(em); > BUG_ON(em_end <= cur); > BUG_ON(end < cur); > - iosize = min(em_end - cur, end - cur + 1); > + iosize = min_t(u64, em_end - cur, blocksize); > iosize = ALIGN(iosize, blocksize); This limits us to do one block per loop, if two blocks are contiguous, it should be fine to write them along. > sector = (em->block_start + extent_offset) >> 9; > bdev = em->bdev; > @@ -3488,32 +3482,20 @@ static noinline_for_stack int > __extent_writepage_io(struct inode *inode, > free_extent_map(em); > em = NULL; > > - /* > - * compressed and inline extents are written through other > - * paths in the FS > - */ > - if (compressed || block_start == EXTENT_MAP_HOLE || > - block_start == EXTENT_MAP_INLINE) { > - /* > - * end_io notification does not happen here for > - * compressed extents > - */ > - if (!compressed && tree->ops && > - tree->ops->writepage_end_io_hook) > - tree->ops->writepage_end_io_hook(page, cur, > - cur + iosize - 1, > - NULL, 1); > - else if (compressed) { > - /* we don't want to end_page_writeback on > - * a compressed extent. this happens > - * elsewhere > - */ > - nr++; > - } > + BUG_ON(compressed); > + BUG_ON(block_start == EXTENT_MAP_INLINE); > > - cur += iosize; > - pg_offset += iosize; > - continue; > + if (block_start == EXTENT_MAP_HOLE) { > + if (test_page_blks_state(page, BLK_STATE_UPTODATE, cur, > + cur + iosize - 1, 1)) { > + clear_page_blks_state(page, > + 1 << BLK_STATE_DIRTY, cur, > + cur + iosize - 1); > + cur += iosize; > + continue; > + } else { > + BUG(); > + } > } > > if (tree->ops && tree->ops->writepage_io_hook) { > @@ -3527,7 +3509,13 @@ static noinline_for_stack int > __extent_writepage_io(struct inode *inode, > } else { > unsigned long max_nr = (i_size >> PAGE_CACHE_SHIFT) + 1; > > - set_range_writeback(tree, cur, cur + iosize - 1); > + clear_page_blks_state(page, 1 << BLK_STATE_DIRTY, cur, > + cur + iosize - 1); > + set_page_writeback(page); > + > + set_page_blks_state(page, 1 << BLK_STATE_IO, cur, > + cur + iosize - 1); > + > if (!PageWriteback(page)) { > btrfs_err(BTRFS_I(inode)->root->fs_info, > "page %lu not writeback, cur %llu > end %llu", > @@ -3542,17 +3530,14 @@ static noinline_for_stack int > __extent_writepage_io(struct inode *inode, > if (ret) > SetPageError(page); > } > - cur = cur + iosize; > - pg_offset += iosize; > + > + cur += iosize; > nr++; > } > done: > *nr_ret = nr; > > done_unlocked: > - > - /* drop our reference on any cached states */ > - free_extent_state(cached_state); > return ret; > } > > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 23b6e03..cbe6381 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -495,6 +495,9 @@ int btrfs_dirty_pages(struct btrfs_root *root, struct > inode *inode, > u64 num_bytes; > u64 start_pos; > u64 end_of_last_block; > + u64 start; > + u64 end; > + u64 page_end; > u64 end_pos = pos + write_bytes; > loff_t isize = i_size_read(inode); > > @@ -507,11 +510,24 @@ int btrfs_dirty_pages(struct btrfs_root *root, struct > inode *inode, > if (err) > return err; > > + start = start_pos; > + > for (i = 0; i < num_pages; i++) { > struct page *p = pages[i]; > SetPageUptodate(p); > ClearPageChecked(p); > + > + end = page_end = page_offset(p) + PAGE_CACHE_SIZE - 1; > + > + if (i == num_pages - 1) > + end = min_t(u64, page_end, end_of_last_block); > + > + set_page_blks_state(p, > + 1 << BLK_STATE_DIRTY | 1 << BLK_STATE_UPTODATE, > + start, end); > set_page_dirty(p); > + > + start = page_end + 1; This is not the usual way, page_end is unnecessary, (start += PAGE_CACHE_SIZE) should work. > } > > /* > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 8262f83..ac6a3f3 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -1995,6 +1995,11 @@ again: > } > > btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state); > + > + set_page_blks_state(page, > + 1 << BLK_STATE_DIRTY | 1 << BLK_STATE_UPTODATE, > + page_start, page_end); > + > ClearPageChecked(page); > set_page_dirty(page); > out: > @@ -2984,26 +2989,48 @@ static int btrfs_writepage_end_io_hook(struct page > *page, u64 start, u64 end, > struct btrfs_ordered_extent *ordered_extent = NULL; > struct btrfs_workqueue *wq; > btrfs_work_func_t func; > + u64 ordered_start, ordered_end; > + int done; > > trace_btrfs_writepage_end_io_hook(page, start, end, uptodate); > > ClearPagePrivate2(page); > - if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start, > - end - start + 1, uptodate)) > - return 0; > +loop: > + ordered_extent = btrfs_lookup_ordered_range(inode, start, > + end - start + 1); > + if (!ordered_extent) > + goto out; > > - if (btrfs_is_free_space_inode(inode)) { > - wq = root->fs_info->endio_freespace_worker; > - func = btrfs_freespace_write_helper; > - } else { > - wq = root->fs_info->endio_write_workers; > - func = btrfs_endio_write_helper; > + ordered_start = max_t(u64, start, ordered_extent->file_offset); > + ordered_end = min_t(u64, end, > + ordered_extent->file_offset + ordered_extent->len - 1); > + > + done = btrfs_dec_test_ordered_pending(inode, &ordered_extent, > + ordered_start, > + ordered_end - ordered_start + 1, > + uptodate); > + if (done) { > + if (btrfs_is_free_space_inode(inode)) { > + wq = root->fs_info->endio_freespace_worker; > + func = btrfs_freespace_write_helper; > + } else { > + wq = root->fs_info->endio_write_workers; > + func = btrfs_endio_write_helper; > + } > + > + btrfs_init_work(&ordered_extent->work, func, > + finish_ordered_fn, NULL, NULL); > + btrfs_queue_work(wq, &ordered_extent->work); > } > > - btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL, > - NULL); > - btrfs_queue_work(wq, &ordered_extent->work); > + btrfs_put_ordered_extent(ordered_extent); > + > + start = ordered_end + 1; > + > + if (start < end) > + goto loop; > > +out: I saw this's put a BUG_ON(block_start == EXTENT_MAP_INLINE); in writepage(), but I didn't see the code of disabling inline data in patch 01 and patch 02, but anyway I think we can avoid above searching for ordered_extents in a single page if we enable inline data. Thanks, -liubo > return 0; > } > > @@ -4601,6 +4628,9 @@ again: > goto out_unlock; > } > > + set_page_blks_state(page, 1 << BLK_STATE_DIRTY | 1 << > BLK_STATE_UPTODATE, > + page_start, page_end); > + > if (offset != PAGE_CACHE_SIZE) { > if (!len) > len = PAGE_CACHE_SIZE - offset; > @@ -8590,6 +8620,10 @@ again: > ret = VM_FAULT_SIGBUS; > goto out_unlock; > } > + > + set_page_blks_state(page, 1 << BLK_STATE_DIRTY | 1 << > BLK_STATE_UPTODATE, > + page_start, end); > + > ret = 0; > > /* page is wholly or partially inside EOF */ > -- > 2.1.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
