Commit 6994ca36 authored by David Sterba's avatar David Sterba
Browse files

btrfs: free-space-cache: use unaligned helpers to access data 



The free space inode stores the tracking data, checksums etc, using the
io_ctl structure and moving the pointers. The data are generally aligned
to at least 4 bytes (u32 for CRC) so it's not completely unaligned but
for clarity we should use the proper helpers whenever a struct is
initialized from io_ctl->cur pointer.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e2f896b3

fs/btrfs/free-space-cache.c

+9 −12
Original line number Diff line number Diff line
@@ -413,8 +413,6 @@ static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate) 


static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)

{

	__le64 *val;



	io_ctl_map_page(io_ctl, 1);



	/*
@@ -429,14 +427,13 @@ static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation) 
		io_ctl->size -= sizeof(u64) * 2;

	}



	val = io_ctl->cur;

	*val = cpu_to_le64(generation);

	put_unaligned_le64(generation, io_ctl->cur);

	io_ctl->cur += sizeof(u64);

}



static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)

{

	__le64 *gen;

	u64 cache_gen;



	/*

	 * Skip the crc area.  If we don't check crcs then we just have a 64bit
@@ -451,11 +448,11 @@ static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation) 
		io_ctl->size -= sizeof(u64) * 2;

	}



	gen = io_ctl->cur;

	if (le64_to_cpu(*gen) != generation) {

	cache_gen = get_unaligned_le64(io_ctl->cur);

	if (cache_gen != generation) {

		btrfs_err_rl(io_ctl->fs_info,

			"space cache generation (%llu) does not match inode (%llu)",

				*gen, generation);

				cache_gen, generation);

		io_ctl_unmap_page(io_ctl);

		return -EIO;

	}
@@ -525,8 +522,8 @@ static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes, 
		return -ENOSPC;



	entry = io_ctl->cur;

	entry->offset = cpu_to_le64(offset);

	entry->bytes = cpu_to_le64(bytes);

	put_unaligned_le64(offset, &entry->offset);

	put_unaligned_le64(bytes, &entry->bytes);

	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :

		BTRFS_FREE_SPACE_EXTENT;

	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
@@ -599,8 +596,8 @@ static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl, 
	}



	e = io_ctl->cur;

	entry->offset = le64_to_cpu(e->offset);

	entry->bytes = le64_to_cpu(e->bytes);

	entry->offset = get_unaligned_le64(&e->offset);

	entry->bytes = get_unaligned_le64(&e->bytes);

	*type = e->type;

	io_ctl->cur += sizeof(struct btrfs_free_space_entry);

	io_ctl->size -= sizeof(struct btrfs_free_space_entry);

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