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Btrfs: early work to file_write in big extents
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Signed-off-by: Chris Mason <chris.mason@oracle.com>
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Chris Mason authored and David Woodhouse committed Apr 16, 2007
1 parent b4100d6 commit 6567e83
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Showing 4 changed files with 232 additions and 23 deletions.
54 changes: 54 additions & 0 deletions fs/btrfs/ctree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1249,6 +1249,60 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
return ret;
}

int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, u32 data_size)
{
int ret = 0;
int slot;
int slot_orig;
struct btrfs_leaf *leaf;
struct buffer_head *leaf_buf;
u32 nritems;
unsigned int data_end;
unsigned int old_data;
unsigned int old_size;
int i;

slot_orig = path->slots[0];
leaf_buf = path->nodes[0];
leaf = btrfs_buffer_leaf(leaf_buf);

nritems = btrfs_header_nritems(&leaf->header);
data_end = leaf_data_end(root, leaf);

if (btrfs_leaf_free_space(root, leaf) < data_size)
BUG();
slot = path->slots[0];
old_data = btrfs_item_end(leaf->items + slot);

BUG_ON(slot < 0);
BUG_ON(slot >= nritems);

/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff = btrfs_item_offset(leaf->items + i);
btrfs_set_item_offset(leaf->items + i,
ioff - data_size);
}
/* shift the data */
btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
data_end - data_size, btrfs_leaf_data(leaf) +
data_end, old_data - data_end);
data_end = old_data;
old_size = btrfs_item_size(leaf->items + slot);
btrfs_set_item_size(leaf->items + slot, old_size + data_size);
btrfs_mark_buffer_dirty(leaf_buf);

ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0)
BUG();
check_leaf(root, path, 0);
return ret;
}

/*
* Given a key and some data, insert an item into the tree.
* This does all the path init required, making room in the tree if needed.
Expand Down
15 changes: 15 additions & 0 deletions fs/btrfs/ctree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -227,6 +227,7 @@ struct btrfs_file_extent_item {
} __attribute__ ((__packed__));

struct btrfs_csum_item {
__le64 extent_offset;
u8 csum[BTRFS_CSUM_SIZE];
} __attribute__ ((__packed__));

Expand Down Expand Up @@ -924,6 +925,17 @@ static inline void btrfs_set_file_extent_num_blocks(struct
e->num_blocks = cpu_to_le64(val);
}

static inline u64 btrfs_csum_extent_offset(struct btrfs_csum_item *c)
{
return le64_to_cpu(c->extent_offset);
}

static inline void btrfs_set_csum_extent_offset(struct btrfs_csum_item *c,
u64 val)
{
c->extent_offset = cpu_to_le64(val);
}

static inline u16 btrfs_device_pathlen(struct btrfs_device_item *d)
{
return le16_to_cpu(d->pathlen);
Expand Down Expand Up @@ -1002,6 +1014,8 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
btrfs_root *root);
/* ctree.c */
int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, u32 data_size);
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *key, struct btrfs_path *p, int
ins_len, int cow);
Expand Down Expand Up @@ -1071,6 +1085,7 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
u64 extent_offset,
char *data, size_t len);
int btrfs_csum_verify_file_block(struct btrfs_root *root,
u64 objectid, u64 offset,
Expand Down
111 changes: 104 additions & 7 deletions fs/btrfs/file-item.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,9 @@
#include "disk-io.h"
#include "transaction.h"

#define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
sizeof(struct btrfs_item)) / \
sizeof(struct btrfs_csum_item)) - 1))
int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
Expand Down Expand Up @@ -43,6 +46,54 @@ int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
return 0;
}

static struct btrfs_csum_item *__lookup_csum_item(struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset)
{
int ret;
struct btrfs_key file_key;
struct btrfs_key found_key;
struct btrfs_csum_item *item;
struct btrfs_leaf *leaf;
u64 csum_offset = 0;

file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
ret = btrfs_search_slot(NULL, root, &file_key, path, 0, 0);
if (ret < 0)
goto fail;
leaf = btrfs_buffer_leaf(path->nodes[0]);
if (ret > 0) {
ret = 1;
if (path->slots[0] == 0)
goto fail;
path->slots[0]--;
btrfs_disk_key_to_cpu(&found_key,
&leaf->items[path->slots[0]].key);
if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
found_key.objectid != objectid) {
goto fail;
}
csum_offset = (offset - found_key.offset) >>
root->fs_info->sb->s_blocksize_bits;
if (csum_offset >=
btrfs_item_size(leaf->items + path->slots[0]) /
sizeof(struct btrfs_csum_item)) {
goto fail;
}
}
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
item += csum_offset;
return item;
fail:
if (ret > 0)
ret = -EIO;
return ERR_PTR(ret);
}


int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid,
Expand All @@ -52,24 +103,33 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_key file_key;
int ins_len = mod < 0 ? -1 : 0;
int cow = mod != 0;
struct btrfs_csum_item *csum_item;

csum_item = __lookup_csum_item(root, path, objectid, offset);
if (IS_ERR(csum_item))
return PTR_ERR(csum_item);
file_key.objectid = objectid;
file_key.offset = offset;
file_key.offset = btrfs_csum_extent_offset(csum_item);
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
btrfs_release_path(root, path);
ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
return ret;
}

int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
u64 extent_offset,
char *data, size_t len)
{
int ret;
struct btrfs_key file_key;
struct btrfs_key found_key;
struct btrfs_path *path;
struct btrfs_csum_item *item;
struct btrfs_leaf *leaf;
u64 csum_offset;

path = btrfs_alloc_path();
BUG_ON(!path);
Expand All @@ -78,14 +138,50 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
ret = btrfs_search_slot(trans, root, &file_key, path,
sizeof(struct btrfs_csum_item), 1);
if (ret < 0)
goto fail;
if (ret == 0) {
csum_offset = 0;
goto csum;
}
if (path->slots[0] == 0) {
btrfs_release_path(root, path);
goto insert;
}
path->slots[0]--;
leaf = btrfs_buffer_leaf(path->nodes[0]);
btrfs_disk_key_to_cpu(&found_key, &leaf->items[path->slots[0]].key);
csum_offset = (offset - found_key.offset) >>
root->fs_info->sb->s_blocksize_bits;
if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
found_key.objectid != objectid ||
csum_offset >= MAX_CSUM_ITEMS(root)) {
btrfs_release_path(root, path);
goto insert;
}
if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) /
sizeof(struct btrfs_csum_item)) {
ret = btrfs_extend_item(trans, root, path,
sizeof(struct btrfs_csum_item));
BUG_ON(ret);
goto csum;
}

insert:
csum_offset = 0;
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
BTRFS_CSUM_SIZE);
sizeof(struct btrfs_csum_item));
if (ret != 0 && ret != -EEXIST)
goto fail;
csum:
item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_csum_item);
ret = 0;
item += csum_offset;
ret = btrfs_csum_data(root, data, len, item->csum);
btrfs_set_csum_extent_offset(item, extent_offset);
btrfs_mark_buffer_dirty(path->nodes[0]);
fail:
btrfs_release_path(root, path);
Expand All @@ -111,12 +207,13 @@ int btrfs_csum_verify_file_block(struct btrfs_root *root,
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
mutex_lock(&root->fs_info->fs_mutex);
ret = btrfs_search_slot(NULL, root, &file_key, path, 0, 0);
if (ret)

item = __lookup_csum_item(root, path, objectid, offset);
if (IS_ERR(item)) {
ret = PTR_ERR(item);
goto fail;
item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_csum_item);
ret = 0;
}

ret = btrfs_csum_data(root, data, len, result);
WARN_ON(ret);
if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
Expand Down
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