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Btrfs: Handle data checksumming on bios that span multiple ordered ex…
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…tents

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: Chris Mason <chris.mason@oracle.com>
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@chrismason-xx
chrismason-xx committed Sep 25, 2008
1 parent eb84ae0 commit 3edf7d3
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Showing 5 changed files with 69 additions and 31 deletions.
4 changes: 2 additions & 2 deletions fs/btrfs/ctree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
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43 changes: 39 additions & 4 deletions fs/btrfs/file-item.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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;
}

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6 changes: 1 addition & 5 deletions fs/btrfs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
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36 changes: 18 additions & 18 deletions fs/btrfs/ordered-data.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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)
Expand All @@ -534,14 +531,17 @@ 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;
ret = 0;
goto out;
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:
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11 changes: 9 additions & 2 deletions fs/btrfs/ordered-data.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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);
}
Expand All @@ -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,
Expand Down

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