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Commit 72c50887 authored by Peng Tao's avatar Peng Tao Committed by Trond Myklebust
Browse files

pnfsblock: move find lock page logic out of bl_write_pagelist 



Also avoid unnecessary lock_page if page is handled by others.

Signed-off-by: default avatarPeng Tao <peng_tao@emc.com>
Signed-off-by: default avatarBenny Halevy <bhalevy@tonian.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 60c52e3a

fs/nfs/blocklayout/blocklayout.c

+54 −24
Original line number Diff line number Diff line
@@ -490,6 +490,55 @@ init_page_for_write(struct page *page, struct pnfs_block_extent *cow_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_write_data *wdata, int sync)

{
@@ -549,32 +598,13 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync) 
			dprintk("%s zero %dth page: index %lu isect %llu\n",

				__func__, npg_zero, index,

				(unsigned long long)isect);

			page =

			    find_or_create_page(wdata->inode->i_mapping, index,

						GFP_NOFS);

			if (!page) {

				dprintk("%s oom\n", __func__);

				wdata->pnfs_error = -ENOMEM;

			page = bl_find_get_zeroing_page(wdata->inode, index,

							cow_read);

			if (unlikely(IS_ERR(page))) {

				wdata->pnfs_error = PTR_ERR(page);

				goto out;

			}



			/* PageDirty: Other will write this out

			 * PageWriteback: Other is writing this out

			 * PageUptodate: It was read before

			 * sector_initialized: already written out

			 */

			if (PageDirty(page) || PageWriteback(page)) {

				print_page(page);

				unlock_page(page);

				page_cache_release(page);

			} else if (page == NULL)

				goto next_page;

			}

			if (!PageUptodate(page)) {

				/* New page, readin or zero it */

				init_page_for_write(page, cow_read);

			}

			set_page_writeback(page);

			unlock_page(page);



			ret = bl_mark_sectors_init(be->be_inval, isect,

						       PAGE_CACHE_SECTORS);