Also avoid unnecessary lock_page if page is handled by others.
Signed-off-by: Peng Tao <peng_tao@xxxxxxx>
---
fs/nfs/blocklayout/blocklayout.c | 78 ++++++++++++++++++++++++++------------
1 files changed, 54 insertions(+), 24 deletions(-)
diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 4ced0b0..c83ad70 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -484,6 +484,55 @@ cleanup:
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)
{
@@ -543,32 +592,13 @@ fill_invalid_ext:
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);
--
1.7.1.262.g5ef3d
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