@@ -1805,10 +1805,118 @@ bool btrfs_find_delalloc_range(struct extent_io_tree *tree, u64 *start,
return found;
}
+/*
+ * Process one page for __process_pages_contig().
+ *
+ * Return >0 if we hit @page == @locked_page.
+ * Return 0 if we updated the page status.
+ * Return -EGAIN if the we need to try again.
+ * (For PAGE_LOCK case but got dirty page or page not belong to mapping)
+ */
+static int process_one_page(struct address_space *mapping,
+ struct page *page, struct page *locked_page,
+ unsigned long page_ops)
+{
+ if (page_ops & PAGE_SET_ORDERED)
+ SetPageOrdered(page);
+
+ if (page == locked_page)
+ return 1;
+
+ if (page_ops & PAGE_SET_ERROR)
+ SetPageError(page);
+ if (page_ops & PAGE_START_WRITEBACK) {
+ clear_page_dirty_for_io(page);
+ set_page_writeback(page);
+ }
+ if (page_ops & PAGE_END_WRITEBACK)
+ end_page_writeback(page);
+ if (page_ops & PAGE_LOCK) {
+ lock_page(page);
+ if (!PageDirty(page) || page->mapping != mapping) {
+ unlock_page(page);
+ return -EAGAIN;
+ }
+ }
+ if (page_ops & PAGE_UNLOCK)
+ unlock_page(page);
+ return 0;
+}
+
static int __process_pages_contig(struct address_space *mapping,
struct page *locked_page,
u64 start, u64 end, unsigned long page_ops,
- u64 *processed_end);
+ u64 *processed_end)
+{
+ pgoff_t start_index = start >> PAGE_SHIFT;
+ pgoff_t end_index = end >> PAGE_SHIFT;
+ pgoff_t index = start_index;
+ unsigned long nr_pages = end_index - start_index + 1;
+ unsigned long pages_processed = 0;
+ struct page *pages[16];
+ int err = 0;
+ int i;
+
+ if (page_ops & PAGE_LOCK) {
+ ASSERT(page_ops == PAGE_LOCK);
+ ASSERT(processed_end && *processed_end == start);
+ }
+
+ if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
+ mapping_set_error(mapping, -EIO);
+
+ while (nr_pages > 0) {
+ int found_pages;
+
+ found_pages = find_get_pages_contig(mapping, index,
+ min_t(unsigned long,
+ nr_pages, ARRAY_SIZE(pages)), pages);
+ if (found_pages == 0) {
+ /*
+ * Only if we're going to lock these pages,
+ * can we find nothing at @index.
+ */
+ ASSERT(page_ops & PAGE_LOCK);
+ err = -EAGAIN;
+ goto out;
+ }
+
+ for (i = 0; i < found_pages; i++) {
+ int process_ret;
+
+ process_ret = process_one_page(mapping, pages[i],
+ locked_page, page_ops);
+ if (process_ret < 0) {
+ for (; i < found_pages; i++)
+ put_page(pages[i]);
+ err = -EAGAIN;
+ goto out;
+ }
+ put_page(pages[i]);
+ pages_processed++;
+ }
+ nr_pages -= found_pages;
+ index += found_pages;
+ cond_resched();
+ }
+out:
+ if (err && processed_end) {
+ /*
+ * Update @processed_end. I know this is awful since it has
+ * two different return value patterns (inclusive vs exclusive).
+ *
+ * But the exclusive pattern is necessary if @start is 0, or we
+ * underflow and check against processed_end won't work as
+ * expected.
+ */
+ if (pages_processed)
+ *processed_end = min(end,
+ ((u64)(start_index + pages_processed) << PAGE_SHIFT) - 1);
+ else
+ *processed_end = start;
+ }
+ return err;
+}
static noinline void __unlock_for_delalloc(struct inode *inode,
struct page *locked_page,
@@ -1936,102 +2044,6 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
return found;
}
-static int __process_pages_contig(struct address_space *mapping,
- struct page *locked_page,
- u64 start, u64 end, unsigned long page_ops,
- u64 *processed_end)
-{
- pgoff_t start_index = start >> PAGE_SHIFT;
- pgoff_t end_index = end >> PAGE_SHIFT;
- pgoff_t index = start_index;
- unsigned long nr_pages = end_index - start_index + 1;
- unsigned long pages_processed = 0;
- struct page *pages[16];
- unsigned ret;
- int err = 0;
- int i;
-
- if (page_ops & PAGE_LOCK) {
- ASSERT(page_ops == PAGE_LOCK);
- ASSERT(processed_end && *processed_end == start);
- }
-
- if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
- mapping_set_error(mapping, -EIO);
-
- while (nr_pages > 0) {
- int found_pages;
-
- found_pages = find_get_pages_contig(mapping, index,
- min_t(unsigned long,
- nr_pages, ARRAY_SIZE(pages)), pages);
- if (found_pages == 0) {
- /*
- * Only if we're going to lock these pages,
- * can we find nothing at @index.
- */
- ASSERT(page_ops & PAGE_LOCK);
- err = -EAGAIN;
- goto out;
- }
-
- for (i = 0; i < ret; i++) {
- if (page_ops & PAGE_SET_ORDERED)
- SetPageOrdered(pages[i]);
-
- if (locked_page && pages[i] == locked_page) {
- put_page(pages[i]);
- pages_processed++;
- continue;
- }
- if (page_ops & PAGE_START_WRITEBACK) {
- clear_page_dirty_for_io(pages[i]);
- set_page_writeback(pages[i]);
- }
- if (page_ops & PAGE_SET_ERROR)
- SetPageError(pages[i]);
- if (page_ops & PAGE_END_WRITEBACK)
- end_page_writeback(pages[i]);
- if (page_ops & PAGE_UNLOCK)
- unlock_page(pages[i]);
- if (page_ops & PAGE_LOCK) {
- lock_page(pages[i]);
- if (!PageDirty(pages[i]) ||
- pages[i]->mapping != mapping) {
- unlock_page(pages[i]);
- for (; i < ret; i++)
- put_page(pages[i]);
- err = -EAGAIN;
- goto out;
- }
- }
- put_page(pages[i]);
- pages_processed++;
- }
- nr_pages -= found_pages;
- index += found_pages;
- cond_resched();
- }
-out:
- if (err && processed_end) {
- /*
- * Update @processed_end. I know this is awful since it has
- * two different return value patterns (inclusive vs exclusive).
- *
- * But the exclusive pattern is necessary if @start is 0, or we
- * underflow and check against processed_end won't work as
- * expected.
- */
- if (pages_processed)
- *processed_end = min(end,
- ((u64)(start_index + pages_processed) << PAGE_SHIFT) - 1);
- else
- *processed_end = start;
-
- }
- return err;
-}
-
void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
struct page *locked_page,
u32 clear_bits, unsigned long page_ops)
In __process_pages_contig() we update page status according to page_ops. That update process is a bunch of if () {} branches, which lies inside two loops, this makes it pretty hard to expand for later subpage operations. So this patch will extract this operations into its own function, process_one_pages(). Also since we're refactoring __process_pages_contig(), also move the new helper and __process_pages_contig() before the first caller of them, to remove the forward declaration. Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/extent_io.c | 206 +++++++++++++++++++++++-------------------- 1 file changed, 109 insertions(+), 97 deletions(-)