linux/fs/btrfs/file-item.c
Josef Bacik 4b46fce233 Btrfs: add basic DIO read/write support
This provides basic DIO support for reading and writing.  It does not do the
work to recover from mismatching checksums, that will come later.  A few design
changes have been made from Jim's code (sorry Jim!)

1) Use the generic direct-io code.  Jim originally re-wrote all the generic DIO
code in order to account for all of BTRFS's oddities, but thanks to that work it
seems like the best bet is to just ignore compression and such and just opt to
fallback on buffered IO.

2) Fallback on buffered IO for compressed or inline extents.  Jim's code did
it's own buffering to make dio with compressed extents work.  Now we just
fallback onto normal buffered IO.

3) Use ordered extents for the writes so that all of the

lock_extent()
lookup_ordered()

type checks continue to work.

4) Do the lock_extent() lookup_ordered() loop in readpage so we don't race with
DIO writes.

I've tested this with fsx and everything works great.  This patch depends on my
dio and filemap.c patches to work.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25 10:34:57 -04:00

855 lines
22 KiB
C

/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#define MAX_CSUM_ITEMS(r, size) ((((BTRFS_LEAF_DATA_SIZE(r) - \
sizeof(struct btrfs_item) * 2) / \
size) - 1))
#define MAX_ORDERED_SUM_BYTES(r) ((PAGE_SIZE - \
sizeof(struct btrfs_ordered_sum)) / \
sizeof(struct btrfs_sector_sum) * \
(r)->sectorsize - (r)->sectorsize)
int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 pos,
u64 disk_offset, u64 disk_num_bytes,
u64 num_bytes, u64 offset, u64 ram_bytes,
u8 compression, u8 encryption, u16 other_encoding)
{
int ret = 0;
struct btrfs_file_extent_item *item;
struct btrfs_key file_key;
struct btrfs_path *path;
struct extent_buffer *leaf;
path = btrfs_alloc_path();
BUG_ON(!path);
file_key.objectid = objectid;
file_key.offset = pos;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
sizeof(*item));
if (ret < 0)
goto out;
BUG_ON(ret);
leaf = path->nodes[0];
item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
btrfs_set_file_extent_offset(leaf, item, offset);
btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
btrfs_set_file_extent_generation(leaf, item, trans->transid);
btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_compression(leaf, item, compression);
btrfs_set_file_extent_encryption(leaf, item, encryption);
btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
btrfs_mark_buffer_dirty(leaf);
out:
btrfs_free_path(path);
return ret;
}
struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u64 bytenr, int cow)
{
int ret;
struct btrfs_key file_key;
struct btrfs_key found_key;
struct btrfs_csum_item *item;
struct extent_buffer *leaf;
u64 csum_offset = 0;
u16 csum_size =
btrfs_super_csum_size(&root->fs_info->super_copy);
int csums_in_item;
file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
file_key.offset = bytenr;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
if (ret < 0)
goto fail;
leaf = path->nodes[0];
if (ret > 0) {
ret = 1;
if (path->slots[0] == 0)
goto fail;
path->slots[0]--;
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY)
goto fail;
csum_offset = (bytenr - found_key.offset) >>
root->fs_info->sb->s_blocksize_bits;
csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
csums_in_item /= csum_size;
if (csum_offset >= csums_in_item) {
ret = -EFBIG;
goto fail;
}
}
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
item = (struct btrfs_csum_item *)((unsigned char *)item +
csum_offset * csum_size);
return item;
fail:
if (ret > 0)
ret = -ENOENT;
return ERR_PTR(ret);
}
int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid,
u64 offset, int mod)
{
int ret;
struct btrfs_key file_key;
int ins_len = mod < 0 ? -1 : 0;
int cow = mod != 0;
file_key.objectid = objectid;
file_key.offset = offset;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
return ret;
}
static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
struct inode *inode, struct bio *bio,
u64 logical_offset, u32 *dst, int dio)
{
u32 sum;
struct bio_vec *bvec = bio->bi_io_vec;
int bio_index = 0;
u64 offset = 0;
u64 item_start_offset = 0;
u64 item_last_offset = 0;
u64 disk_bytenr;
u32 diff;
u16 csum_size =
btrfs_super_csum_size(&root->fs_info->super_copy);
int ret;
struct btrfs_path *path;
struct btrfs_csum_item *item = NULL;
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
path = btrfs_alloc_path();
if (bio->bi_size > PAGE_CACHE_SIZE * 8)
path->reada = 2;
WARN_ON(bio->bi_vcnt <= 0);
disk_bytenr = (u64)bio->bi_sector << 9;
if (dio)
offset = logical_offset;
while (bio_index < bio->bi_vcnt) {
if (!dio)
offset = page_offset(bvec->bv_page) + bvec->bv_offset;
ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum);
if (ret == 0)
goto found;
if (!item || disk_bytenr < item_start_offset ||
disk_bytenr >= item_last_offset) {
struct btrfs_key found_key;
u32 item_size;
if (item)
btrfs_release_path(root, path);
item = btrfs_lookup_csum(NULL, root->fs_info->csum_root,
path, disk_bytenr, 0);
if (IS_ERR(item)) {
ret = PTR_ERR(item);
if (ret == -ENOENT || ret == -EFBIG)
ret = 0;
sum = 0;
if (BTRFS_I(inode)->root->root_key.objectid ==
BTRFS_DATA_RELOC_TREE_OBJECTID) {
set_extent_bits(io_tree, offset,
offset + bvec->bv_len - 1,
EXTENT_NODATASUM, GFP_NOFS);
} else {
printk(KERN_INFO "btrfs no csum found "
"for inode %lu start %llu\n",
inode->i_ino,
(unsigned long long)offset);
}
item = NULL;
btrfs_release_path(root, path);
goto found;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
item_start_offset = found_key.offset;
item_size = btrfs_item_size_nr(path->nodes[0],
path->slots[0]);
item_last_offset = item_start_offset +
(item_size / csum_size) *
root->sectorsize;
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_csum_item);
}
/*
* this byte range must be able to fit inside
* a single leaf so it will also fit inside a u32
*/
diff = disk_bytenr - item_start_offset;
diff = diff / root->sectorsize;
diff = diff * csum_size;
read_extent_buffer(path->nodes[0], &sum,
((unsigned long)item) + diff,
csum_size);
found:
if (dst)
*dst++ = sum;
else
set_state_private(io_tree, offset, sum);
disk_bytenr += bvec->bv_len;
offset += bvec->bv_len;
bio_index++;
bvec++;
}
btrfs_free_path(path);
return 0;
}
int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
struct bio *bio, u32 *dst)
{
return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0);
}
int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
struct bio *bio, u64 offset, u32 *dst)
{
return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1);
}
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
struct list_head *list)
{
struct btrfs_key key;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_ordered_sum *sums;
struct btrfs_sector_sum *sector_sum;
struct btrfs_csum_item *item;
unsigned long offset;
int ret;
size_t size;
u64 csum_end;
u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
path = btrfs_alloc_path();
BUG_ON(!path);
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.offset = start;
key.type = BTRFS_EXTENT_CSUM_KEY;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto fail;
if (ret > 0 && path->slots[0] > 0) {
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
key.type == BTRFS_EXTENT_CSUM_KEY) {
offset = (start - key.offset) >>
root->fs_info->sb->s_blocksize_bits;
if (offset * csum_size <
btrfs_item_size_nr(leaf, path->slots[0] - 1))
path->slots[0]--;
}
}
while (start <= end) {
leaf = path->nodes[0];
if (path->slots[0] >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto fail;
if (ret > 0)
break;
leaf = path->nodes[0];
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
key.type != BTRFS_EXTENT_CSUM_KEY)
break;
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.offset > end)
break;
if (key.offset > start)
start = key.offset;
size = btrfs_item_size_nr(leaf, path->slots[0]);
csum_end = key.offset + (size / csum_size) * root->sectorsize;
if (csum_end <= start) {
path->slots[0]++;
continue;
}
csum_end = min(csum_end, end + 1);
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_csum_item);
while (start < csum_end) {
size = min_t(size_t, csum_end - start,
MAX_ORDERED_SUM_BYTES(root));
sums = kzalloc(btrfs_ordered_sum_size(root, size),
GFP_NOFS);
BUG_ON(!sums);
sector_sum = sums->sums;
sums->bytenr = start;
sums->len = size;
offset = (start - key.offset) >>
root->fs_info->sb->s_blocksize_bits;
offset *= csum_size;
while (size > 0) {
read_extent_buffer(path->nodes[0],
&sector_sum->sum,
((unsigned long)item) +
offset, csum_size);
sector_sum->bytenr = start;
size -= root->sectorsize;
start += root->sectorsize;
offset += csum_size;
sector_sum++;
}
list_add_tail(&sums->list, list);
}
path->slots[0]++;
}
ret = 0;
fail:
btrfs_free_path(path);
return ret;
}
int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
struct bio *bio, u64 file_start, int contig)
{
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;
u64 disk_bytenr;
WARN_ON(bio->bi_vcnt <= 0);
sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
if (!sums)
return -ENOMEM;
sector_sum = sums->sums;
disk_bytenr = (u64)bio->bi_sector << 9;
sums->len = bio->bi_size;
INIT_LIST_HEAD(&sums->list);
if (contig)
offset = file_start;
else
offset = page_offset(bvec->bv_page) + bvec->bv_offset;
ordered = btrfs_lookup_ordered_extent(inode, offset);
BUG_ON(!ordered);
sums->bytenr = ordered->start;
while (bio_index < bio->bi_vcnt) {
if (!contig)
offset = page_offset(bvec->bv_page) + bvec->bv_offset;
if (!contig && (offset >= ordered->file_offset + ordered->len ||
offset < ordered->file_offset)) {
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;
ordered = btrfs_lookup_ordered_extent(inode, offset);
BUG_ON(!ordered);
sums->bytenr = ordered->start;
}
data = kmap_atomic(bvec->bv_page, KM_USER0);
sector_sum->sum = ~(u32)0;
sector_sum->sum = btrfs_csum_data(root,
data + bvec->bv_offset,
sector_sum->sum,
bvec->bv_len);
kunmap_atomic(data, KM_USER0);
btrfs_csum_final(sector_sum->sum,
(char *)&sector_sum->sum);
sector_sum->bytenr = disk_bytenr;
sector_sum++;
bio_index++;
total_bytes += bvec->bv_len;
this_sum_bytes += bvec->bv_len;
disk_bytenr += bvec->bv_len;
offset += bvec->bv_len;
bvec++;
}
this_sum_bytes = 0;
btrfs_add_ordered_sum(inode, ordered, sums);
btrfs_put_ordered_extent(ordered);
return 0;
}
/*
* helper function for csum removal, this expects the
* key to describe the csum pointed to by the path, and it expects
* the csum to overlap the range [bytenr, len]
*
* The csum should not be entirely contained in the range and the
* range should not be entirely contained in the csum.
*
* This calls btrfs_truncate_item with the correct args based on the
* overlap, and fixes up the key as required.
*/
static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *key,
u64 bytenr, u64 len)
{
struct extent_buffer *leaf;
u16 csum_size =
btrfs_super_csum_size(&root->fs_info->super_copy);
u64 csum_end;
u64 end_byte = bytenr + len;
u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
int ret;
leaf = path->nodes[0];
csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
csum_end <<= root->fs_info->sb->s_blocksize_bits;
csum_end += key->offset;
if (key->offset < bytenr && csum_end <= end_byte) {
/*
* [ bytenr - len ]
* [ ]
* [csum ]
* A simple truncate off the end of the item
*/
u32 new_size = (bytenr - key->offset) >> blocksize_bits;
new_size *= csum_size;
ret = btrfs_truncate_item(trans, root, path, new_size, 1);
BUG_ON(ret);
} else if (key->offset >= bytenr && csum_end > end_byte &&
end_byte > key->offset) {
/*
* [ bytenr - len ]
* [ ]
* [csum ]
* we need to truncate from the beginning of the csum
*/
u32 new_size = (csum_end - end_byte) >> blocksize_bits;
new_size *= csum_size;
ret = btrfs_truncate_item(trans, root, path, new_size, 0);
BUG_ON(ret);
key->offset = end_byte;
ret = btrfs_set_item_key_safe(trans, root, path, key);
BUG_ON(ret);
} else {
BUG();
}
return 0;
}
/*
* deletes the csum items from the csum tree for a given
* range of bytes.
*/
int btrfs_del_csums(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 bytenr, u64 len)
{
struct btrfs_path *path;
struct btrfs_key key;
u64 end_byte = bytenr + len;
u64 csum_end;
struct extent_buffer *leaf;
int ret;
u16 csum_size =
btrfs_super_csum_size(&root->fs_info->super_copy);
int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
root = root->fs_info->csum_root;
path = btrfs_alloc_path();
while (1) {
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.offset = end_byte - 1;
key.type = BTRFS_EXTENT_CSUM_KEY;
path->leave_spinning = 1;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
if (path->slots[0] == 0)
goto out;
path->slots[0]--;
}
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
key.type != BTRFS_EXTENT_CSUM_KEY) {
break;
}
if (key.offset >= end_byte)
break;
csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
csum_end <<= blocksize_bits;
csum_end += key.offset;
/* this csum ends before we start, we're done */
if (csum_end <= bytenr)
break;
/* delete the entire item, it is inside our range */
if (key.offset >= bytenr && csum_end <= end_byte) {
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
if (key.offset == bytenr)
break;
} else if (key.offset < bytenr && csum_end > end_byte) {
unsigned long offset;
unsigned long shift_len;
unsigned long item_offset;
/*
* [ bytenr - len ]
* [csum ]
*
* Our bytes are in the middle of the csum,
* we need to split this item and insert a new one.
*
* But we can't drop the path because the
* csum could change, get removed, extended etc.
*
* The trick here is the max size of a csum item leaves
* enough room in the tree block for a single
* item header. So, we split the item in place,
* adding a new header pointing to the existing
* bytes. Then we loop around again and we have
* a nicely formed csum item that we can neatly
* truncate.
*/
offset = (bytenr - key.offset) >> blocksize_bits;
offset *= csum_size;
shift_len = (len >> blocksize_bits) * csum_size;
item_offset = btrfs_item_ptr_offset(leaf,
path->slots[0]);
memset_extent_buffer(leaf, 0, item_offset + offset,
shift_len);
key.offset = bytenr;
/*
* btrfs_split_item returns -EAGAIN when the
* item changed size or key
*/
ret = btrfs_split_item(trans, root, path, &key, offset);
BUG_ON(ret && ret != -EAGAIN);
key.offset = end_byte - 1;
} else {
ret = truncate_one_csum(trans, root, path,
&key, bytenr, len);
BUG_ON(ret);
if (key.offset < bytenr)
break;
}
btrfs_release_path(root, path);
}
out:
btrfs_free_path(path);
return 0;
}
int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_ordered_sum *sums)
{
u64 bytenr;
int ret;
struct btrfs_key file_key;
struct btrfs_key found_key;
u64 next_offset;
u64 total_bytes = 0;
int found_next;
struct btrfs_path *path;
struct btrfs_csum_item *item;
struct btrfs_csum_item *item_end;
struct extent_buffer *leaf = NULL;
u64 csum_offset;
struct btrfs_sector_sum *sector_sum;
u32 nritems;
u32 ins_size;
char *eb_map;
char *eb_token;
unsigned long map_len;
unsigned long map_start;
u16 csum_size =
btrfs_super_csum_size(&root->fs_info->super_copy);
path = btrfs_alloc_path();
BUG_ON(!path);
sector_sum = sums->sums;
again:
next_offset = (u64)-1;
found_next = 0;
file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
file_key.offset = sector_sum->bytenr;
bytenr = sector_sum->bytenr;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1);
if (!IS_ERR(item)) {
leaf = path->nodes[0];
ret = 0;
goto found;
}
ret = PTR_ERR(item);
if (ret != -EFBIG && ret != -ENOENT)
goto fail_unlock;
if (ret == -EFBIG) {
u32 item_size;
/* we found one, but it isn't big enough yet */
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if ((item_size / csum_size) >=
MAX_CSUM_ITEMS(root, csum_size)) {
/* already at max size, make a new one */
goto insert;
}
} else {
int slot = path->slots[0] + 1;
/* we didn't find a csum item, insert one */
nritems = btrfs_header_nritems(path->nodes[0]);
if (path->slots[0] >= nritems - 1) {
ret = btrfs_next_leaf(root, path);
if (ret == 1)
found_next = 1;
if (ret != 0)
goto insert;
slot = 0;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
found_key.type != BTRFS_EXTENT_CSUM_KEY) {
found_next = 1;
goto insert;
}
next_offset = found_key.offset;
found_next = 1;
goto insert;
}
/*
* at this point, we know the tree has an item, but it isn't big
* enough yet to put our csum in. Grow it
*/
btrfs_release_path(root, path);
ret = btrfs_search_slot(trans, root, &file_key, path,
csum_size, 1);
if (ret < 0)
goto fail_unlock;
if (ret > 0) {
if (path->slots[0] == 0)
goto insert;
path->slots[0]--;
}
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
csum_offset = (bytenr - found_key.offset) >>
root->fs_info->sb->s_blocksize_bits;
if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY ||
found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
goto insert;
}
if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
csum_size) {
u32 diff = (csum_offset + 1) * csum_size;
/*
* is the item big enough already? we dropped our lock
* before and need to recheck
*/
if (diff < btrfs_item_size_nr(leaf, path->slots[0]))
goto csum;
diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
if (diff != csum_size)
goto insert;
ret = btrfs_extend_item(trans, root, path, diff);
BUG_ON(ret);
goto csum;
}
insert:
btrfs_release_path(root, path);
csum_offset = 0;
if (found_next) {
u64 tmp = total_bytes + root->sectorsize;
u64 next_sector = sector_sum->bytenr;
struct btrfs_sector_sum *next = sector_sum + 1;
while (tmp < sums->len) {
if (next_sector + root->sectorsize != next->bytenr)
break;
tmp += root->sectorsize;
next_sector = next->bytenr;
next++;
}
tmp = min(tmp, next_offset - file_key.offset);
tmp >>= root->fs_info->sb->s_blocksize_bits;
tmp = max((u64)1, tmp);
tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
ins_size = csum_size * tmp;
} else {
ins_size = csum_size;
}
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
ins_size);
path->leave_spinning = 0;
if (ret < 0)
goto fail_unlock;
if (ret != 0) {
WARN_ON(1);
goto fail_unlock;
}
csum:
leaf = path->nodes[0];
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
ret = 0;
item = (struct btrfs_csum_item *)((unsigned char *)item +
csum_offset * csum_size);
found:
item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
btrfs_item_size_nr(leaf, path->slots[0]));
eb_token = NULL;
next_sector:
if (!eb_token ||
(unsigned long)item + csum_size >= map_start + map_len) {
int err;
if (eb_token)
unmap_extent_buffer(leaf, eb_token, KM_USER1);
eb_token = NULL;
err = map_private_extent_buffer(leaf, (unsigned long)item,
csum_size,
&eb_token, &eb_map,
&map_start, &map_len, KM_USER1);
if (err)
eb_token = NULL;
}
if (eb_token) {
memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
&sector_sum->sum, csum_size);
} else {
write_extent_buffer(leaf, &sector_sum->sum,
(unsigned long)item, csum_size);
}
total_bytes += root->sectorsize;
sector_sum++;
if (total_bytes < sums->len) {
item = (struct btrfs_csum_item *)((char *)item +
csum_size);
if (item < item_end && bytenr + PAGE_CACHE_SIZE ==
sector_sum->bytenr) {
bytenr = sector_sum->bytenr;
goto next_sector;
}
}
if (eb_token) {
unmap_extent_buffer(leaf, eb_token, KM_USER1);
eb_token = NULL;
}
btrfs_mark_buffer_dirty(path->nodes[0]);
if (total_bytes < sums->len) {
btrfs_release_path(root, path);
cond_resched();
goto again;
}
out:
btrfs_free_path(path);
return ret;
fail_unlock:
goto out;
}