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Commit 2b108268 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: don't use highmem for free space cache pages 



In order to create the free space cache concurrently with FS modifications,
we need to take a few block group locks.

The cache code also does kmap, which would schedule with the locks held.
Instead of going through kmap_atomic, lets just use lowmem for the cache
pages.

Signed-off-by: default avatarChris Mason <clm@fb.com>
parent c9dc4c65

fs/btrfs/free-space-cache.c

+5 −7
Original line number Diff line number Diff line
@@ -85,7 +85,8 @@ static struct inode *__lookup_free_space_inode(struct btrfs_root *root, 
	}



	mapping_set_gfp_mask(inode->i_mapping,

			mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);

			mapping_gfp_mask(inode->i_mapping) &

			~(GFP_NOFS & ~__GFP_HIGHMEM));



	return inode;

}
@@ -310,7 +311,6 @@ static void io_ctl_free(struct btrfs_io_ctl *io_ctl) 
static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)

{

	if (io_ctl->cur) {

		kunmap(io_ctl->page);

		io_ctl->cur = NULL;

		io_ctl->orig = NULL;

	}
@@ -320,7 +320,7 @@ static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear) 
{

	ASSERT(io_ctl->index < io_ctl->num_pages);

	io_ctl->page = io_ctl->pages[io_ctl->index++];

	io_ctl->cur = kmap(io_ctl->page);

	io_ctl->cur = page_address(io_ctl->page);

	io_ctl->orig = io_ctl->cur;

	io_ctl->size = PAGE_CACHE_SIZE;

	if (clear)
@@ -446,10 +446,9 @@ static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index) 
			      PAGE_CACHE_SIZE - offset);

	btrfs_csum_final(crc, (char *)&crc);

	io_ctl_unmap_page(io_ctl);

	tmp = kmap(io_ctl->pages[0]);

	tmp = page_address(io_ctl->pages[0]);

	tmp += index;

	*tmp = crc;

	kunmap(io_ctl->pages[0]);

}



static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
@@ -466,10 +465,9 @@ static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index) 
	if (index == 0)

		offset = sizeof(u32) * io_ctl->num_pages;



	tmp = kmap(io_ctl->pages[0]);

	tmp = page_address(io_ctl->pages[0]);

	tmp += index;

	val = *tmp;

	kunmap(io_ctl->pages[0]);



	io_ctl_map_page(io_ctl, 0);

	crc = btrfs_csum_data(io_ctl->orig + offset, crc,