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Commit 71a63551 authored by David Sterba's avatar David Sterba
Browse files

btrfs: switch to on-stack csum buffer in csum_tree_block 



The maximum size of a checksum buffer is known, BTRFS_CSUM_SIZE, and we
don't have to allocate it dynamically. This code path is not used at all
as we have only the crc32c and use an on-stack buffer already.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 343e4fc1

fs/btrfs/disk-io.c

+3 −13
Original line number Diff line number Diff line
@@ -285,7 +285,7 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info, 
			   int verify)

{

	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);

	char *result = NULL;

	char result[BTRFS_CSUM_SIZE];

	unsigned long len;

	unsigned long cur_len;

	unsigned long offset = BTRFS_CSUM_SIZE;
@@ -294,7 +294,6 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info, 
	unsigned long map_len;

	int err;

	u32 crc = ~(u32)0;

	unsigned long inline_result;



	len = buf->len - offset;

	while (len > 0) {
@@ -308,13 +307,7 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info, 
		len -= cur_len;

		offset += cur_len;

	}

	if (csum_size > sizeof(inline_result)) {

		result = kzalloc(csum_size, GFP_NOFS);

		if (!result)

			return -ENOMEM;

	} else {

		result = (char *)&inline_result;

	}

	memset(result, 0, BTRFS_CSUM_SIZE);



	btrfs_csum_final(crc, result);
@@ -329,15 +322,12 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info, 
				"%s checksum verify failed on %llu wanted %X found %X level %d",

				fs_info->sb->s_id, buf->start,

				val, found, btrfs_header_level(buf));

			if (result != (char *)&inline_result)

				kfree(result);

			return -EUCLEAN;

		}

	} else {

		write_extent_buffer(buf, result, 0, csum_size);

	}

	if (result != (char *)&inline_result)

		kfree(result);



	return 0;

}