Commit 98af9ab1 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: pass bytenr directly to __process_pages_contig() 



As a preparation for incoming subpage support, we need bytenr passed to
__process_pages_contig() directly, not the current page index.

So change the parameter and all callers to pass bytenr in.

With the modification, here we need to replace the old @index_ret with
@processed_end for __process_pages_contig(), but this brings a small
problem.

Normally we follow the inclusive return value, meaning @processed_end
should be the last byte we processed.

If parameter @start is 0, and we failed to lock any page, then we would
return @processed_end as -1, causing more problems for
__unlock_for_delalloc().

So here for @processed_end, we use two different return value patterns.
If we have locked any page, @processed_end will be the last byte of
locked page.
Or it will be @start otherwise.

This change will impact lock_delalloc_pages(), so it needs to check
@processed_end to only unlock the range if we have locked any.

Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64]
Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64]
Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 968f2566

fs/btrfs/extent_io.c

+37 −20
Original line number Diff line number Diff line
@@ -1810,8 +1810,8 @@ bool btrfs_find_delalloc_range(struct extent_io_tree *tree, u64 *start, 


static int __process_pages_contig(struct address_space *mapping,

				  struct page *locked_page,

				  pgoff_t start_index, pgoff_t end_index,

				  unsigned long page_ops, pgoff_t *index_ret);

				  u64 start, u64 end, unsigned long page_ops,

				  u64 *processed_end);



static noinline void __unlock_for_delalloc(struct inode *inode,

					   struct page *locked_page,
@@ -1824,7 +1824,7 @@ static noinline void __unlock_for_delalloc(struct inode *inode, 
	if (index == locked_page->index && end_index == index)

		return;



	__process_pages_contig(inode->i_mapping, locked_page, index, end_index,

	__process_pages_contig(inode->i_mapping, locked_page, start, end,

			       PAGE_UNLOCK, NULL);

}
@@ -1834,19 +1834,19 @@ static noinline int lock_delalloc_pages(struct inode *inode, 
					u64 delalloc_end)

{

	unsigned long index = delalloc_start >> PAGE_SHIFT;

	unsigned long index_ret = index;

	unsigned long end_index = delalloc_end >> PAGE_SHIFT;

	u64 processed_end = delalloc_start;

	int ret;



	ASSERT(locked_page);

	if (index == locked_page->index && index == end_index)

		return 0;



	ret = __process_pages_contig(inode->i_mapping, locked_page, index,

				     end_index, PAGE_LOCK, &index_ret);

	if (ret == -EAGAIN)

	ret = __process_pages_contig(inode->i_mapping, locked_page, delalloc_start,

				     delalloc_end, PAGE_LOCK, &processed_end);

	if (ret == -EAGAIN && processed_end > delalloc_start)

		__unlock_for_delalloc(inode, locked_page, delalloc_start,

				      (u64)index_ret << PAGE_SHIFT);

				      processed_end);

	return ret;

}
@@ -1941,12 +1941,14 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode, 


static int __process_pages_contig(struct address_space *mapping,

				  struct page *locked_page,

				  pgoff_t start_index, pgoff_t end_index,

				  unsigned long page_ops, pgoff_t *index_ret)

				  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;

	pgoff_t index = start_index;

	struct page *pages[16];

	unsigned ret;

	int err = 0;
@@ -1954,17 +1956,19 @@ static int __process_pages_contig(struct address_space *mapping, 


	if (page_ops & PAGE_LOCK) {

		ASSERT(page_ops == PAGE_LOCK);

		ASSERT(index_ret && *index_ret == start_index);

		ASSERT(processed_end && *processed_end == start);

	}



	if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)

		mapping_set_error(mapping, -EIO);



	while (nr_pages > 0) {

		ret = find_get_pages_contig(mapping, index,

		int found_pages;



		found_pages = find_get_pages_contig(mapping, index,

				     min_t(unsigned long,

				     nr_pages, ARRAY_SIZE(pages)), pages);

		if (ret == 0) {

		if (found_pages == 0) {

			/*

			 * Only if we're going to lock these pages,

			 * can we find nothing at @index.
@@ -2007,13 +2011,27 @@ static int __process_pages_contig(struct address_space *mapping, 
			put_page(pages[i]);

			pages_processed++;

		}

		nr_pages -= ret;

		index += ret;

		nr_pages -= found_pages;

		index += found_pages;

		cond_resched();

	}

out:

	if (err && index_ret)

		*index_ret = start_index + pages_processed - 1;

	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;

}
@@ -2024,8 +2042,7 @@ void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end, 
	clear_extent_bit(&inode->io_tree, start, end, clear_bits, 1, 0, NULL);



	__process_pages_contig(inode->vfs_inode.i_mapping, locked_page,

			       start >> PAGE_SHIFT, end >> PAGE_SHIFT,

			       page_ops, NULL);

			       start, end, page_ops, NULL);

}



/*