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nilfs2: Convert to XArray 

This is close to a 1:1 replacement of radix tree APIs with their XArray
equivalents.  It would be possible to optimise nilfs_copy_back_pages(),
but that doesn't seem to be in the performance path.  Also, I think
it has a pre-existing bug, and I've added a note to that effect in the
source code.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox 2017-12-04 19:33:30 -05:00
parent 04edf02cdd
commit f611ff6375
2 changed files with 22 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
fs/nilfs2/btnode.c
View File

@ -168,24 +168,18 @@ int nilfs_btnode_prepare_change_key(struct address_space *btnc,
ctxt->newbh = NULL;
if (inode->i_blkbits == PAGE_SHIFT) {
lock_page(obh->b_page);
/*
* We cannot call radix_tree_preload for the kernels older
* than 2.6.23, because it is not exported for modules.
*/
struct page *opage = obh->b_page;
lock_page(opage);
retry:
err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
if (err)
goto failed_unlock;
/* BUG_ON(oldkey != obh->b_page->index); */
if (unlikely(oldkey != obh->b_page->index))
NILFS_PAGE_BUG(obh->b_page,
if (unlikely(oldkey != opage->index))
NILFS_PAGE_BUG(opage,
"invalid oldkey %lld (newkey=%lld)",
(unsigned long long)oldkey,
(unsigned long long)newkey);
xa_lock_irq(&btnc->i_pages);
err = radix_tree_insert(&btnc->i_pages, newkey, obh->b_page);
err = __xa_insert(&btnc->i_pages, newkey, opage, GFP_NOFS);
xa_unlock_irq(&btnc->i_pages);
/*
* Note: page->index will not change to newkey until
@ -193,7 +187,6 @@ retry:
* To protect the page in intermediate state, the page lock
* is held.
*/
radix_tree_preload_end();
if (!err)
return 0;
else if (err != -EEXIST)
@ -203,7 +196,7 @@ retry:
if (!err)
goto retry;
/* fallback to copy mode */
unlock_page(obh->b_page);
unlock_page(opage);
}
nbh = nilfs_btnode_create_block(btnc, newkey);
@ -243,9 +236,8 @@ void nilfs_btnode_commit_change_key(struct address_space *btnc,
mark_buffer_dirty(obh);
xa_lock_irq(&btnc->i_pages);
radix_tree_delete(&btnc->i_pages, oldkey);
radix_tree_tag_set(&btnc->i_pages, newkey,
PAGECACHE_TAG_DIRTY);
__xa_erase(&btnc->i_pages, oldkey);
__xa_set_mark(&btnc->i_pages, newkey, PAGECACHE_TAG_DIRTY);
xa_unlock_irq(&btnc->i_pages);
opage->index = obh->b_blocknr = newkey;
@ -275,7 +267,7 @@ void nilfs_btnode_abort_change_key(struct address_space *btnc,
if (nbh == NULL) { /* blocksize == pagesize */
xa_lock_irq(&btnc->i_pages);
radix_tree_delete(&btnc->i_pages, newkey);
__xa_erase(&btnc->i_pages, newkey);
xa_unlock_irq(&btnc->i_pages);
unlock_page(ctxt->bh->b_page);
} else

27
fs/nilfs2/page.c
View File

@ -289,7 +289,7 @@ repeat:
* @dmap: destination page cache
* @smap: source page cache
*
* No pages must no be added to the cache during this process.
* No pages must be added to the cache during this process.
* This must be ensured by the caller.
*/
void nilfs_copy_back_pages(struct address_space *dmap,
@ -298,7 +298,6 @@ void nilfs_copy_back_pages(struct address_space *dmap,
struct pagevec pvec;
unsigned int i, n;
pgoff_t index = 0;
int err;
pagevec_init(&pvec);
repeat:
@ -313,34 +312,33 @@ repeat:
lock_page(page);
dpage = find_lock_page(dmap, offset);
if (dpage) {
/* override existing page on the destination cache */
/* overwrite existing page in the destination cache */
WARN_ON(PageDirty(dpage));
nilfs_copy_page(dpage, page, 0);
unlock_page(dpage);
put_page(dpage);
/* Do we not need to remove page from smap here? */
} else {
struct page *page2;
struct page *p;
/* move the page to the destination cache */
xa_lock_irq(&smap->i_pages);
page2 = radix_tree_delete(&smap->i_pages, offset);
WARN_ON(page2 != page);
p = __xa_erase(&smap->i_pages, offset);
WARN_ON(page != p);
smap->nrpages--;
xa_unlock_irq(&smap->i_pages);
xa_lock_irq(&dmap->i_pages);
err = radix_tree_insert(&dmap->i_pages, offset, page);
if (unlikely(err < 0)) {
WARN_ON(err == -EEXIST);
p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS);
if (unlikely(p)) {
/* Probably -ENOMEM */
page->mapping = NULL;
put_page(page); /* for cache */
put_page(page);
} else {
page->mapping = dmap;
dmap->nrpages++;
if (PageDirty(page))
radix_tree_tag_set(&dmap->i_pages,
offset,
__xa_set_mark(&dmap->i_pages, offset,
PAGECACHE_TAG_DIRTY);
}
xa_unlock_irq(&dmap->i_pages);
@ -467,8 +465,7 @@ int __nilfs_clear_page_dirty(struct page *page)
if (mapping) {
xa_lock_irq(&mapping->i_pages);
if (test_bit(PG_dirty, &page->flags)) {
radix_tree_tag_clear(&mapping->i_pages,
page_index(page),
__xa_clear_mark(&mapping->i_pages, page_index(page),
PAGECACHE_TAG_DIRTY);
xa_unlock_irq(&mapping->i_pages);
return clear_page_dirty_for_io(page);