Return-Path: linux-nfs-owner@vger.kernel.org Received: from casper.infradead.org ([85.118.1.10]:45783 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754267AbaHGHVl (ORCPT ); Thu, 7 Aug 2014 03:21:41 -0400 From: Christoph Hellwig To: Trond Myklebust Cc: linux-nfs@vger.kernel.org Subject: [PATCH 12/17] pnfs/blocklayout: remove read-modify-write handling in bl_write_pagelist Date: Thu, 7 Aug 2014 09:23:44 +0200 Message-Id: <1407396229-4785-13-git-send-email-hch@lst.de> In-Reply-To: <1407396229-4785-1-git-send-email-hch@lst.de> References: <1407396229-4785-1-git-send-email-hch@lst.de> Sender: linux-nfs-owner@vger.kernel.org List-ID: Use the new PNFS_READ_WHOLE_PAGE flag to offload read-modify-write handling to core nfs code, and remove a huge chunk of deadlock prone mess from the block layout writeback path. Signed-off-by: Christoph Hellwig --- fs/nfs/blocklayout/blocklayout.c | 500 +++++---------------------------------- 1 file changed, 64 insertions(+), 436 deletions(-) diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c index 87a633d..6484b9f 100644 --- a/fs/nfs/blocklayout/blocklayout.c +++ b/fs/nfs/blocklayout/blocklayout.c @@ -35,7 +35,6 @@ #include #include #include /* struct bio */ -#include /* various write calls */ #include #include @@ -188,16 +187,6 @@ retry: return bio; } -static struct bio *bl_add_page_to_bio(struct bio *bio, int npg, int rw, - sector_t isect, struct page *page, - struct pnfs_block_extent *be, - void (*end_io)(struct bio *, int err), - struct parallel_io *par) -{ - return do_add_page_to_bio(bio, npg, rw, isect, page, be, - end_io, par, 0, PAGE_CACHE_SIZE); -} - /* This is basically copied from mpage_end_io_read */ static void bl_end_io_read(struct bio *bio, int err) { @@ -293,8 +282,8 @@ bl_read_pagelist(struct nfs_pgio_header *hdr) } } + pg_offset = f_offset & ~PAGE_CACHE_MASK; if (is_dio) { - pg_offset = f_offset & ~PAGE_CACHE_MASK; if (pg_offset + bytes_left > PAGE_CACHE_SIZE) pg_len = PAGE_CACHE_SIZE - pg_offset; else @@ -305,7 +294,7 @@ bl_read_pagelist(struct nfs_pgio_header *hdr) isect += (pg_offset >> SECTOR_SHIFT); extent_length -= (pg_offset >> SECTOR_SHIFT); } else { - pg_offset = 0; + BUG_ON(pg_offset != 0); pg_len = PAGE_CACHE_SIZE; } @@ -383,29 +372,6 @@ static void mark_extents_written(struct pnfs_block_layout *bl, } } -static void bl_end_io_write_zero(struct bio *bio, int err) -{ - struct parallel_io *par = bio->bi_private; - struct bio_vec *bvec; - int i; - - bio_for_each_segment_all(bvec, bio, i) { - /* This is the zeroing page we added */ - end_page_writeback(bvec->bv_page); - page_cache_release(bvec->bv_page); - } - - if (unlikely(err)) { - struct nfs_pgio_header *header = par->data; - - if (!header->pnfs_error) - header->pnfs_error = -EIO; - pnfs_set_lo_fail(header->lseg); - } - bio_put(bio); - put_parallel(par); -} - static void bl_end_io_write(struct bio *bio, int err) { struct parallel_io *par = bio->bi_private; @@ -455,256 +421,22 @@ static void bl_end_par_io_write(void *data, int num_se) schedule_work(&hdr->task.u.tk_work); } -/* FIXME STUB - mark intersection of layout and page as bad, so is not - * used again. - */ -static void mark_bad_read(void) -{ - return; -} - -/* - * map_block: map a requested I/0 block (isect) into an offset in the LVM - * block_device - */ -static void -map_block(struct buffer_head *bh, sector_t isect, struct pnfs_block_extent *be) -{ - dprintk("%s enter be=%p\n", __func__, be); - - set_buffer_mapped(bh); - bh->b_bdev = be->be_mdev; - bh->b_blocknr = (isect - be->be_f_offset + be->be_v_offset) >> - (be->be_mdev->bd_inode->i_blkbits - SECTOR_SHIFT); - - dprintk("%s isect %llu, bh->b_blocknr %ld, using bsize %Zd\n", - __func__, (unsigned long long)isect, (long)bh->b_blocknr, - bh->b_size); - return; -} - -static void -bl_read_single_end_io(struct bio *bio, int error) -{ - struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; - struct page *page = bvec->bv_page; - - /* Only one page in bvec */ - unlock_page(page); -} - -static int -bl_do_readpage_sync(struct page *page, struct pnfs_block_extent *be, - unsigned int offset, unsigned int len) -{ - struct bio *bio; - struct page *shadow_page; - sector_t isect; - char *kaddr, *kshadow_addr; - int ret = 0; - - dprintk("%s: offset %u len %u\n", __func__, offset, len); - - shadow_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); - if (shadow_page == NULL) - return -ENOMEM; - - bio = bio_alloc(GFP_NOIO, 1); - if (bio == NULL) - return -ENOMEM; - - isect = (page->index << PAGE_CACHE_SECTOR_SHIFT) + - (offset / SECTOR_SIZE); - - bio->bi_iter.bi_sector = isect - be->be_f_offset + be->be_v_offset; - bio->bi_bdev = be->be_mdev; - bio->bi_end_io = bl_read_single_end_io; - - lock_page(shadow_page); - if (bio_add_page(bio, shadow_page, - SECTOR_SIZE, round_down(offset, SECTOR_SIZE)) == 0) { - unlock_page(shadow_page); - bio_put(bio); - return -EIO; - } - - submit_bio(READ, bio); - wait_on_page_locked(shadow_page); - if (unlikely(!test_bit(BIO_UPTODATE, &bio->bi_flags))) { - ret = -EIO; - } else { - kaddr = kmap_atomic(page); - kshadow_addr = kmap_atomic(shadow_page); - memcpy(kaddr + offset, kshadow_addr + offset, len); - kunmap_atomic(kshadow_addr); - kunmap_atomic(kaddr); - } - __free_page(shadow_page); - bio_put(bio); - - return ret; -} - -static int -bl_read_partial_page_sync(struct page *page, struct pnfs_block_extent *be, - unsigned int dirty_offset, unsigned int dirty_len, - bool full_page) -{ - int ret = 0; - unsigned int start, end; - - if (full_page) { - start = 0; - end = PAGE_CACHE_SIZE; - } else { - start = round_down(dirty_offset, SECTOR_SIZE); - end = round_up(dirty_offset + dirty_len, SECTOR_SIZE); - } - - dprintk("%s: offset %u len %d\n", __func__, dirty_offset, dirty_len); - if (!be) { - zero_user_segments(page, start, dirty_offset, - dirty_offset + dirty_len, end); - if (start == 0 && end == PAGE_CACHE_SIZE && - trylock_page(page)) { - SetPageUptodate(page); - unlock_page(page); - } - return ret; - } - - if (start != dirty_offset) - ret = bl_do_readpage_sync(page, be, start, dirty_offset - start); - - if (!ret && (dirty_offset + dirty_len < end)) - ret = bl_do_readpage_sync(page, be, dirty_offset + dirty_len, - end - dirty_offset - dirty_len); - - return ret; -} - -/* Given an unmapped page, zero it or read in page for COW, page is locked - * by caller. - */ -static int -init_page_for_write(struct page *page, struct pnfs_block_extent *cow_read) -{ - struct buffer_head *bh = NULL; - int ret = 0; - sector_t isect; - - dprintk("%s enter, %p\n", __func__, page); - BUG_ON(PageUptodate(page)); - if (!cow_read) { - zero_user_segment(page, 0, PAGE_SIZE); - SetPageUptodate(page); - goto cleanup; - } - - bh = alloc_page_buffers(page, PAGE_CACHE_SIZE, 0); - if (!bh) { - ret = -ENOMEM; - goto cleanup; - } - - isect = (sector_t) page->index << PAGE_CACHE_SECTOR_SHIFT; - map_block(bh, isect, cow_read); - if (!bh_uptodate_or_lock(bh)) - ret = bh_submit_read(bh); - if (ret) - goto cleanup; - SetPageUptodate(page); - -cleanup: - if (bh) - free_buffer_head(bh); - if (ret) { - /* Need to mark layout with bad read...should now - * just use nfs4 for reads and writes. - */ - mark_bad_read(); - } - return ret; -} - -/* Find or create a zeroing page marked being writeback. - * Return ERR_PTR on error, NULL to indicate skip this page and page itself - * to indicate write out. - */ -static struct page * -bl_find_get_zeroing_page(struct inode *inode, pgoff_t index, - struct pnfs_block_extent *cow_read) -{ - struct page *page; - int locked = 0; - page = find_get_page(inode->i_mapping, index); - if (page) - goto check_page; - - page = find_or_create_page(inode->i_mapping, index, GFP_NOFS); - if (unlikely(!page)) { - dprintk("%s oom\n", __func__); - return ERR_PTR(-ENOMEM); - } - locked = 1; - -check_page: - /* PageDirty: Other will write this out - * PageWriteback: Other is writing this out - * PageUptodate: It was read before - */ - if (PageDirty(page) || PageWriteback(page)) { - print_page(page); - if (locked) - unlock_page(page); - page_cache_release(page); - return NULL; - } - - if (!locked) { - lock_page(page); - locked = 1; - goto check_page; - } - if (!PageUptodate(page)) { - /* New page, readin or zero it */ - init_page_for_write(page, cow_read); - } - set_page_writeback(page); - unlock_page(page); - - return page; -} - static enum pnfs_try_status bl_write_pagelist(struct nfs_pgio_header *header, int sync) { - int i, ret, npg_zero, pg_index, last = 0; + int i, ret; struct bio *bio = NULL; - struct pnfs_block_extent *be = NULL, *cow_read = NULL; - sector_t isect, last_isect = 0, extent_length = 0; + struct pnfs_block_extent *be = NULL; + sector_t isect, extent_length = 0; struct parallel_io *par = NULL; loff_t offset = header->args.offset; size_t count = header->args.count; - unsigned int pg_offset, pg_len, saved_len; struct page **pages = header->args.pages; - struct page *page; - pgoff_t index; - u64 temp; - int npg_per_block = - NFS_SERVER(header->inode)->pnfs_blksize >> PAGE_CACHE_SHIFT; + int pg_index = pg_index = header->args.pgbase >> PAGE_CACHE_SHIFT; struct blk_plug plug; dprintk("%s enter, %Zu@%lld\n", __func__, count, offset); - blk_start_plug(&plug); - - if (header->dreq != NULL && - (!IS_ALIGNED(offset, NFS_SERVER(header->inode)->pnfs_blksize) || - !IS_ALIGNED(count, NFS_SERVER(header->inode)->pnfs_blksize))) { - dprintk("pnfsblock nonblock aligned DIO writes. Resend MDS\n"); - goto out_mds; - } /* At this point, header->page_aray is a (sequential) list of nfs_pages. * We want to write each, and if there is an error set pnfs_error * to have it redone using nfs. @@ -715,97 +447,20 @@ bl_write_pagelist(struct nfs_pgio_header *header, int sync) par->pnfs_callback = bl_end_par_io_write; /* At this point, have to be more careful with error handling */ - isect = (sector_t) ((offset & (long)PAGE_CACHE_MASK) >> SECTOR_SHIFT); - be = bl_find_get_extent(BLK_LSEG2EXT(header->lseg), isect, &cow_read); - if (!be || !is_writable(be, isect)) { - dprintk("%s no matching extents!\n", __func__); - goto out_mds; - } - - /* First page inside INVALID extent */ - if (be->be_state == PNFS_BLOCK_INVALID_DATA) { - if (likely(!bl_push_one_short_extent(be->be_inval))) - par->bse_count++; - else - goto out_mds; - temp = offset >> PAGE_CACHE_SHIFT; - npg_zero = do_div(temp, npg_per_block); - isect = (sector_t) (((offset - npg_zero * PAGE_CACHE_SIZE) & - (long)PAGE_CACHE_MASK) >> SECTOR_SHIFT); - extent_length = be->be_length - (isect - be->be_f_offset); - -fill_invalid_ext: - dprintk("%s need to zero %d pages\n", __func__, npg_zero); - for (;npg_zero > 0; npg_zero--) { - if (bl_is_sector_init(be->be_inval, isect)) { - dprintk("isect %llu already init\n", - (unsigned long long)isect); - goto next_page; - } - /* page ref released in bl_end_io_write_zero */ - index = isect >> PAGE_CACHE_SECTOR_SHIFT; - dprintk("%s zero %dth page: index %lu isect %llu\n", - __func__, npg_zero, index, - (unsigned long long)isect); - page = bl_find_get_zeroing_page(header->inode, index, - cow_read); - if (unlikely(IS_ERR(page))) { - header->pnfs_error = PTR_ERR(page); - goto out; - } else if (page == NULL) - goto next_page; - - ret = bl_mark_sectors_init(be->be_inval, isect, - PAGE_CACHE_SECTORS); - if (unlikely(ret)) { - dprintk("%s bl_mark_sectors_init fail %d\n", - __func__, ret); - end_page_writeback(page); - page_cache_release(page); - header->pnfs_error = ret; - goto out; - } - if (likely(!bl_push_one_short_extent(be->be_inval))) - par->bse_count++; - else { - end_page_writeback(page); - page_cache_release(page); - header->pnfs_error = -ENOMEM; - goto out; - } - /* FIXME: This should be done in bi_end_io */ - mark_extents_written(BLK_LSEG2EXT(header->lseg), - page->index << PAGE_CACHE_SHIFT, - PAGE_CACHE_SIZE); - - bio = bl_add_page_to_bio(bio, npg_zero, WRITE, - isect, page, be, - bl_end_io_write_zero, par); - if (IS_ERR(bio)) { - header->pnfs_error = PTR_ERR(bio); - bio = NULL; - goto out; - } -next_page: - isect += PAGE_CACHE_SECTORS; - extent_length -= PAGE_CACHE_SECTORS; - } - if (last) - goto write_done; - } - bio = bl_submit_bio(WRITE, bio); + blk_start_plug(&plug); - /* Middle pages */ - pg_index = header->args.pgbase >> PAGE_CACHE_SHIFT; + /* we always write out the whole page */ + offset = offset & (loff_t)PAGE_CACHE_MASK; + isect = offset >> SECTOR_SHIFT; + for (i = pg_index; i < header->page_array.npages; i++) { if (extent_length <= 0) { /* We've used up the previous extent */ bl_put_extent(be); - bl_put_extent(cow_read); bio = bl_submit_bio(WRITE, bio); /* Get the next one */ be = bl_find_get_extent(BLK_LSEG2EXT(header->lseg), - isect, &cow_read); + isect, NULL); if (!be || !is_writable(be, isect)) { header->pnfs_error = -EINVAL; goto out; @@ -823,25 +478,10 @@ next_page: (isect - be->be_f_offset); } - dprintk("%s offset %lld count %Zu\n", __func__, offset, count); - pg_offset = offset & ~PAGE_CACHE_MASK; - if (pg_offset + count > PAGE_CACHE_SIZE) - pg_len = PAGE_CACHE_SIZE - pg_offset; - else - pg_len = count; + BUG_ON(offset & ~PAGE_CACHE_MASK); - saved_len = pg_len; if (be->be_state == PNFS_BLOCK_INVALID_DATA && !bl_is_sector_init(be->be_inval, isect)) { - ret = bl_read_partial_page_sync(pages[i], cow_read, - pg_offset, pg_len, true); - if (ret) { - dprintk("%s bl_read_partial_page_sync fail %d\n", - __func__, ret); - header->pnfs_error = ret; - goto out; - } - ret = bl_mark_sectors_init(be->be_inval, isect, PAGE_CACHE_SECTORS); if (unlikely(ret)) { @@ -850,66 +490,31 @@ next_page: header->pnfs_error = ret; goto out; } - - /* Expand to full page write */ - pg_offset = 0; - pg_len = PAGE_CACHE_SIZE; - } else if ((pg_offset & (SECTOR_SIZE - 1)) || - (pg_len & (SECTOR_SIZE - 1))){ - /* ahh, nasty case. We have to do sync full sector - * read-modify-write cycles. - */ - unsigned int saved_offset = pg_offset; - ret = bl_read_partial_page_sync(pages[i], be, pg_offset, - pg_len, false); - pg_offset = round_down(pg_offset, SECTOR_SIZE); - pg_len = round_up(saved_offset + pg_len, SECTOR_SIZE) - - pg_offset; } - bio = do_add_page_to_bio(bio, header->page_array.npages - i, - WRITE, - isect, pages[i], be, + WRITE, isect, pages[i], be, bl_end_io_write, par, - pg_offset, pg_len); + 0, PAGE_CACHE_SIZE); if (IS_ERR(bio)) { header->pnfs_error = PTR_ERR(bio); bio = NULL; goto out; } - offset += saved_len; - count -= saved_len; + offset += PAGE_CACHE_SIZE; + count -= PAGE_CACHE_SIZE; isect += PAGE_CACHE_SECTORS; - last_isect = isect; extent_length -= PAGE_CACHE_SECTORS; } - /* Last page inside INVALID extent */ - if (be->be_state == PNFS_BLOCK_INVALID_DATA) { - bio = bl_submit_bio(WRITE, bio); - temp = last_isect >> PAGE_CACHE_SECTOR_SHIFT; - npg_zero = npg_per_block - do_div(temp, npg_per_block); - if (npg_zero < npg_per_block) { - last = 1; - goto fill_invalid_ext; - } - } - -write_done: header->res.count = header->args.count; out: bl_put_extent(be); - bl_put_extent(cow_read); bl_submit_bio(WRITE, bio); blk_finish_plug(&plug); put_parallel(par); return PNFS_ATTEMPTED; out_mds: - blk_finish_plug(&plug); - bl_put_extent(be); - bl_put_extent(cow_read); - kfree(par); return PNFS_NOT_ATTEMPTED; } @@ -1188,20 +793,45 @@ bl_clear_layoutdriver(struct nfs_server *server) } static bool -is_aligned_req(struct nfs_page *req, unsigned int alignment) +is_aligned_req(struct nfs_pageio_descriptor *pgio, + struct nfs_page *req, unsigned int alignment) { - return IS_ALIGNED(req->wb_offset, alignment) && - IS_ALIGNED(req->wb_bytes, alignment); + /* + * Always accept buffered writes, higher layers take care of the + * right alignment. + */ + if (pgio->pg_dreq == NULL) + return true; + + if (!IS_ALIGNED(req->wb_offset, alignment)) + return false; + + if (IS_ALIGNED(req->wb_bytes, alignment)) + return true; + + if (req_offset(req) + req->wb_bytes == i_size_read(pgio->pg_inode)) { + /* + * If the write goes up to the inode size, just write + * the full page. Data past the inode size is + * guaranteed to be zeroed by the higher level client + * code, and this behaviour is mandated by RFC 5663 + * section 2.3.2. + */ + return true; + } + + return false; } static void bl_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) { - if (pgio->pg_dreq != NULL && - !is_aligned_req(req, SECTOR_SIZE)) + if (!is_aligned_req(pgio, req, SECTOR_SIZE)) { nfs_pageio_reset_read_mds(pgio); - else - pnfs_generic_pg_init_read(pgio, req); + return; + } + + pnfs_generic_pg_init_read(pgio, req); } /* @@ -1212,10 +842,8 @@ static size_t bl_pg_test_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, struct nfs_page *req) { - if (pgio->pg_dreq != NULL && - !is_aligned_req(req, SECTOR_SIZE)) + if (!is_aligned_req(pgio, req, SECTOR_SIZE)) return 0; - return pnfs_generic_pg_test(pgio, prev, req); } @@ -1245,19 +873,20 @@ static u64 pnfs_num_cont_bytes(struct inode *inode, pgoff_t idx) static void bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) { - if (pgio->pg_dreq != NULL && - !is_aligned_req(req, PAGE_CACHE_SIZE)) { + u64 wb_size; + + if (!is_aligned_req(pgio, req, PAGE_SIZE)) { nfs_pageio_reset_write_mds(pgio); - } else { - u64 wb_size; - if (pgio->pg_dreq == NULL) - wb_size = pnfs_num_cont_bytes(pgio->pg_inode, - req->wb_index); - else - wb_size = nfs_dreq_bytes_left(pgio->pg_dreq); - - pnfs_generic_pg_init_write(pgio, req, wb_size); + return; } + + if (pgio->pg_dreq == NULL) + wb_size = pnfs_num_cont_bytes(pgio->pg_inode, + req->wb_index); + else + wb_size = nfs_dreq_bytes_left(pgio->pg_dreq); + + pnfs_generic_pg_init_write(pgio, req, wb_size); } /* @@ -1268,10 +897,8 @@ static size_t bl_pg_test_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, struct nfs_page *req) { - if (pgio->pg_dreq != NULL && - !is_aligned_req(req, PAGE_CACHE_SIZE)) + if (!is_aligned_req(pgio, req, PAGE_SIZE)) return 0; - return pnfs_generic_pg_test(pgio, prev, req); } @@ -1291,6 +918,7 @@ static struct pnfs_layoutdriver_type blocklayout_type = { .id = LAYOUT_BLOCK_VOLUME, .name = "LAYOUT_BLOCK_VOLUME", .owner = THIS_MODULE, + .flags = PNFS_READ_WHOLE_PAGE, .read_pagelist = bl_read_pagelist, .write_pagelist = bl_write_pagelist, .alloc_layout_hdr = bl_alloc_layout_hdr, -- 1.9.1