Commit 3edf7d33 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Handle data checksumming on bios that span multiple ordered extents 



Data checksumming is done right before the bio is sent down the IO stack,
which means a single bio might span more than one ordered extent.  In
this case, the checksumming data is split between two ordered extents.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent eb84ae03

fs/btrfs/ctree.h

+2 −2
Original line number Diff line number Diff line
@@ -1579,8 +1579,8 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, 
int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,

			   struct btrfs_root *root, struct inode *inode,

			   struct btrfs_ordered_sum *sums);

int btrfs_csum_one_bio(struct btrfs_root *root,

		       struct bio *bio, struct btrfs_ordered_sum **sums_ret);

int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,

		       struct bio *bio);

struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,

					  struct btrfs_root *root,

					  struct btrfs_path *path,

fs/btrfs/file-item.c

+39 −4
Original line number Diff line number Diff line
@@ -134,26 +134,53 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, 
	return ret;

}



int btrfs_csum_one_bio(struct btrfs_root *root,

		       struct bio *bio, struct btrfs_ordered_sum **sums_ret)

int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,

		       struct bio *bio)

{

	struct btrfs_ordered_sum *sums;

	struct btrfs_sector_sum *sector_sum;

	struct btrfs_ordered_extent *ordered;

	char *data;

	struct bio_vec *bvec = bio->bi_io_vec;

	int bio_index = 0;

	unsigned long total_bytes = 0;

	unsigned long this_sum_bytes = 0;

	u64 offset;



	WARN_ON(bio->bi_vcnt <= 0);

	sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);

	if (!sums)

		return -ENOMEM;

	*sums_ret = sums;



	sector_sum = &sums->sums;

	sums->file_offset = page_offset(bvec->bv_page);

	sums->file_offset = page_offset(bvec->bv_page) + bvec->bv_offset;

	sums->len = bio->bi_size;

	INIT_LIST_HEAD(&sums->list);

	ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);

	BUG_ON(!ordered);



	while(bio_index < bio->bi_vcnt) {

		offset = page_offset(bvec->bv_page) + bvec->bv_offset;

		if (offset >= ordered->file_offset + ordered->len) {

			unsigned long bytes_left;

			sums->len = this_sum_bytes;

			this_sum_bytes = 0;

			btrfs_add_ordered_sum(inode, ordered, sums);

			btrfs_put_ordered_extent(ordered);



			bytes_left = bio->bi_size - total_bytes;



			sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),

				       GFP_NOFS);

			BUG_ON(!sums);

			sector_sum = &sums->sums;

			sums->len = bytes_left;

			sums->file_offset = offset;

			ordered = btrfs_lookup_ordered_extent(inode,

						      sums->file_offset);

			BUG_ON(!ordered);

		}



		data = kmap_atomic(bvec->bv_page, KM_USER0);

		sector_sum->sum = ~(u32)0;

		sector_sum->sum = btrfs_csum_data(root,
@@ -165,10 +192,18 @@ int btrfs_csum_one_bio(struct btrfs_root *root, 
				 (char *)&sector_sum->sum);

		sector_sum->offset = page_offset(bvec->bv_page) +

			bvec->bv_offset;



		sector_sum++;

		bio_index++;

		total_bytes += bvec->bv_len;

		this_sum_bytes += bvec->bv_len;

		bvec++;

	}

	btrfs_add_ordered_sum(inode, ordered, sums);

	btrfs_put_ordered_extent(ordered);

	if (total_bytes != bio->bi_size) {

printk("warning, total bytes %lu bio size %u\n", total_bytes, bio->bi_size);

	}

	return 0;

}

fs/btrfs/inode.c

+1 −5
Original line number Diff line number Diff line
@@ -351,12 +351,8 @@ int __btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio, 
{

	struct btrfs_root *root = BTRFS_I(inode)->root;

	int ret = 0;

	struct btrfs_ordered_sum *sums;



	ret = btrfs_csum_one_bio(root, bio, &sums);

	BUG_ON(ret);



	ret = btrfs_add_ordered_sum(inode, sums);

	ret = btrfs_csum_one_bio(root, inode, bio);

	BUG_ON(ret);



	return btrfs_map_bio(root, rw, bio, mirror_num, 1);

fs/btrfs/ordered-data.c

+18 −18
Original line number Diff line number Diff line
@@ -186,22 +186,17 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset, 


/*

 * Add a struct btrfs_ordered_sum into the list of checksums to be inserted

 * when an ordered extent is finished.

 * when an ordered extent is finished.  If the list covers more than one

 * ordered extent, it is split across multiples.

 */

int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum)

int btrfs_add_ordered_sum(struct inode *inode,

			  struct btrfs_ordered_extent *entry,

			  struct btrfs_ordered_sum *sum)

{

	struct btrfs_ordered_inode_tree *tree;

	struct rb_node *node;

	struct btrfs_ordered_extent *entry;



	tree = &BTRFS_I(inode)->ordered_tree;

	mutex_lock(&tree->mutex);

	node = tree_search(tree, sum->file_offset);

	BUG_ON(!node);



	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);

	BUG_ON(!offset_in_entry(entry, sum->file_offset));



	list_add_tail(&sum->list, &entry->list);

	mutex_unlock(&tree->mutex);

	return 0;
@@ -524,8 +519,10 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u32 *sum) 
	struct btrfs_ordered_extent *ordered;

	struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;

	struct list_head *cur;

	unsigned long num_sectors;

	unsigned long i;

	u32 sectorsize = BTRFS_I(inode)->root->sectorsize;

	int ret = 1;

	int index;



	ordered = btrfs_lookup_ordered_extent(inode, offset);

	if (!ordered)
@@ -534,16 +531,19 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u32 *sum) 
	mutex_lock(&tree->mutex);

	list_for_each_prev(cur, &ordered->list) {

		ordered_sum = list_entry(cur, struct btrfs_ordered_sum, list);

		if (offset >= ordered_sum->file_offset &&

		    offset < ordered_sum->file_offset + ordered_sum->len) {

			index = (offset - ordered_sum->file_offset) /

				BTRFS_I(inode)->root->sectorsize;;

		if (offset >= ordered_sum->file_offset) {

			num_sectors = ordered_sum->len / sectorsize;

			sector_sums = &ordered_sum->sums;

			*sum = sector_sums[index].sum;

			for (i = 0; i < num_sectors; i++) {

				if (sector_sums[i].offset == offset) {

printk("find ordered sum inode %lu offset %Lu\n", inode->i_ino, offset);

					*sum = sector_sums[i].sum;

					ret = 0;

					goto out;

				}

			}

		}

	}

out:

	mutex_unlock(&tree->mutex);

	return ret;

fs/btrfs/ordered-data.h

+9 −2
Original line number Diff line number Diff line
@@ -39,7 +39,11 @@ struct btrfs_sector_sum { 


struct btrfs_ordered_sum {

	u64 file_offset;

	u64 len;

	/*

	 * this is the length in bytes covered by the sums array below.

	 * But, the sums array may not be contiguous in the file.

	 */

	unsigned long len;

	struct list_head list;

	/* last field is a variable length array of btrfs_sector_sums */

	struct btrfs_sector_sum sums;
@@ -95,6 +99,7 @@ static inline int btrfs_ordered_sum_size(struct btrfs_root *root, u64 bytes) 
{

	unsigned long num_sectors = (bytes + root->sectorsize - 1) /

		root->sectorsize;

	num_sectors++;

	return sizeof(struct btrfs_ordered_sum) +

		num_sectors * sizeof(struct btrfs_sector_sum);

}
@@ -114,7 +119,9 @@ int btrfs_dec_test_ordered_pending(struct inode *inode, 
				       u64 file_offset, u64 io_size);

int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,

			     u64 start, u64 len);

int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum);

int btrfs_add_ordered_sum(struct inode *inode,

			  struct btrfs_ordered_extent *entry,

			  struct btrfs_ordered_sum *sum);

struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,

							 u64 file_offset);

void btrfs_start_ordered_extent(struct inode *inode,

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