microsoft
/
WSL2-Linux-Kernel
зеркало из https://github.com/microsoft/WSL2-Linux-Kernel.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность
WSL2-Linux-Kernel/fs/btrfs/file-item.c

1430 строки
39 KiB
C
Исходник Ответственный История

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/sched/mm.h>
#include <crypto/hash.h>
#include "messages.h"
#include "misc.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "bio.h"
#include "print-tree.h"
#include "compression.h"
#include "fs.h"
#include "accessors.h"
#include "file-item.h"
#include "super.h"
#define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
sizeof(struct btrfs_item) * 2) / \
size) - 1))
#define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
PAGE_SIZE))
/*
* Set inode's size according to filesystem options.
*
* @inode: inode we want to update the disk_i_size for
* @new_i_size: i_size we want to set to, 0 if we use i_size
*
* With NO_HOLES set this simply sets the disk_is_size to whatever i_size_read()
* returns as it is perfectly fine with a file that has holes without hole file
* extent items.
*
* However without NO_HOLES we need to only return the area that is contiguous
* from the 0 offset of the file. Otherwise we could end up adjust i_size up
* to an extent that has a gap in between.
*
* Finally new_i_size should only be set in the case of truncate where we're not
* ready to use i_size_read() as the limiter yet.
*/
void btrfs_inode_safe_disk_i_size_write(struct btrfs_inode *inode, u64 new_i_size)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
u64 start, end, i_size;
int ret;
i_size = new_i_size ?: i_size_read(&inode->vfs_inode);
if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
inode->disk_i_size = i_size;
return;
}
spin_lock(&inode->lock);
ret = find_contiguous_extent_bit(&inode->file_extent_tree, 0, &start,
&end, EXTENT_DIRTY);
if (!ret && start == 0)
i_size = min(i_size, end + 1);
else
i_size = 0;
inode->disk_i_size = i_size;
spin_unlock(&inode->lock);
}
/*
* Mark range within a file as having a new extent inserted.
*
* @inode: inode being modified
* @start: start file offset of the file extent we've inserted
* @len: logical length of the file extent item
*
* Call when we are inserting a new file extent where there was none before.
* Does not need to call this in the case where we're replacing an existing file
* extent, however if not sure it's fine to call this multiple times.
*
* The start and len must match the file extent item, so thus must be sectorsize
* aligned.
*/
int btrfs_inode_set_file_extent_range(struct btrfs_inode *inode, u64 start,
u64 len)
{
if (len == 0)
return 0;
ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize));
if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
return 0;
return set_extent_bits(&inode->file_extent_tree, start, start + len - 1,
EXTENT_DIRTY);
}
/*
* Mark an inode range as not having a backing extent.
*
* @inode: inode being modified
* @start: start file offset of the file extent we've inserted
* @len: logical length of the file extent item
*
* Called when we drop a file extent, for example when we truncate. Doesn't
* need to be called for cases where we're replacing a file extent, like when
* we've COWed a file extent.
*
* The start and len must match the file extent item, so thus must be sectorsize
* aligned.
*/
int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start,
u64 len)
{
if (len == 0)
return 0;
ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize) ||
len == (u64)-1);
if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
return 0;
return clear_extent_bit(&inode->file_extent_tree, start,
start + len - 1, EXTENT_DIRTY, NULL);
}
static size_t bytes_to_csum_size(const struct btrfs_fs_info *fs_info, u32 bytes)
{
ASSERT(IS_ALIGNED(bytes, fs_info->sectorsize));
return (bytes >> fs_info->sectorsize_bits) * fs_info->csum_size;
}
static size_t csum_size_to_bytes(const struct btrfs_fs_info *fs_info, u32 csum_size)
{
ASSERT(IS_ALIGNED(csum_size, fs_info->csum_size));
return (csum_size / fs_info->csum_size) << fs_info->sectorsize_bits;
}
static inline u32 max_ordered_sum_bytes(const struct btrfs_fs_info *fs_info)
{
u32 max_csum_size = round_down(PAGE_SIZE - sizeof(struct btrfs_ordered_sum),
fs_info->csum_size);
return csum_size_to_bytes(fs_info, max_csum_size);
}
/*
* Calculate the total size needed to allocate for an ordered sum structure
* spanning @bytes in the file.
*/
static int btrfs_ordered_sum_size(struct btrfs_fs_info *fs_info, unsigned long bytes)
{
return sizeof(struct btrfs_ordered_sum) + bytes_to_csum_size(fs_info, bytes);
}
int btrfs_insert_hole_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 pos, u64 num_bytes)
{
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();
if (!path)
return -ENOMEM;
file_key.objectid = objectid;
file_key.offset = pos;
file_key.type = BTRFS_EXTENT_DATA_KEY;
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
sizeof(*item));
if (ret < 0)
goto out;
BUG_ON(ret); /* Can't happen */
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, 0);
btrfs_set_file_extent_disk_num_bytes(leaf, item, 0);
btrfs_set_file_extent_offset(leaf, item, 0);
btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, item, num_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, 0);
btrfs_set_file_extent_encryption(leaf, item, 0);
btrfs_set_file_extent_other_encoding(leaf, item, 0);
btrfs_mark_buffer_dirty(leaf);
out:
btrfs_free_path(path);
return ret;
}
static struct btrfs_csum_item *
btrfs_lookup_csum(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u64 bytenr, int cow)
{
struct btrfs_fs_info *fs_info = root->fs_info;
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;
const u32 csum_size = fs_info->csum_size;
int csums_in_item;
file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
file_key.offset = bytenr;
file_key.type = 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 (found_key.type != BTRFS_EXTENT_CSUM_KEY)
goto fail;
csum_offset = (bytenr - found_key.offset) >>
fs_info->sectorsize_bits;
csums_in_item = btrfs_item_size(leaf, path->slots[0]);
csums_in_item /= csum_size;
if (csum_offset == csums_in_item) {
ret = -EFBIG;
goto fail;
} else if (csum_offset > csums_in_item) {
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)
{
struct btrfs_key file_key;
int ins_len = mod < 0 ? -1 : 0;
int cow = mod != 0;
file_key.objectid = objectid;
file_key.offset = offset;
file_key.type = BTRFS_EXTENT_DATA_KEY;
return btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
}
/*
* Find checksums for logical bytenr range [disk_bytenr, disk_bytenr + len) and
* store the result to @dst.
*
* Return >0 for the number of sectors we found.
* Return 0 for the range [disk_bytenr, disk_bytenr + sectorsize) has no csum
* for it. Caller may want to try next sector until one range is hit.
* Return <0 for fatal error.
*/
static int search_csum_tree(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 disk_bytenr,
u64 len, u8 *dst)
{
struct btrfs_root *csum_root;
struct btrfs_csum_item *item = NULL;
struct btrfs_key key;
const u32 sectorsize = fs_info->sectorsize;
const u32 csum_size = fs_info->csum_size;
u32 itemsize;
int ret;
u64 csum_start;
u64 csum_len;
ASSERT(IS_ALIGNED(disk_bytenr, sectorsize) &&
IS_ALIGNED(len, sectorsize));
/* Check if the current csum item covers disk_bytenr */
if (path->nodes[0]) {
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_csum_item);
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
csum_start = key.offset;
csum_len = (itemsize / csum_size) * sectorsize;
if (in_range(disk_bytenr, csum_start, csum_len))
goto found;
}
/* Current item doesn't contain the desired range, search again */
btrfs_release_path(path);
csum_root = btrfs_csum_root(fs_info, disk_bytenr);
item = btrfs_lookup_csum(NULL, csum_root, path, disk_bytenr, 0);
if (IS_ERR(item)) {
ret = PTR_ERR(item);
goto out;
}
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
csum_start = key.offset;
csum_len = (itemsize / csum_size) * sectorsize;
ASSERT(in_range(disk_bytenr, csum_start, csum_len));
found:
ret = (min(csum_start + csum_len, disk_bytenr + len) -
disk_bytenr) >> fs_info->sectorsize_bits;
read_extent_buffer(path->nodes[0], dst, (unsigned long)item,
ret * csum_size);
out:
if (ret == -ENOENT || ret == -EFBIG)
ret = 0;
return ret;
}
/*
* Locate the file_offset of @cur_disk_bytenr of a @bio.
*
* Bio of btrfs represents read range of
* [bi_sector << 9, bi_sector << 9 + bi_size).
* Knowing this, we can iterate through each bvec to locate the page belong to
* @cur_disk_bytenr and get the file offset.
*
* @inode is used to determine if the bvec page really belongs to @inode.
*
* Return 0 if we can't find the file offset
* Return >0 if we find the file offset and restore it to @file_offset_ret
*/
static int search_file_offset_in_bio(struct bio *bio, struct inode *inode,
u64 disk_bytenr, u64 *file_offset_ret)
{
struct bvec_iter iter;
struct bio_vec bvec;
u64 cur = bio->bi_iter.bi_sector << SECTOR_SHIFT;
int ret = 0;
bio_for_each_segment(bvec, bio, iter) {
struct page *page = bvec.bv_page;
if (cur > disk_bytenr)
break;
if (cur + bvec.bv_len <= disk_bytenr) {
cur += bvec.bv_len;
continue;
}
ASSERT(in_range(disk_bytenr, cur, bvec.bv_len));
if (page->mapping && page->mapping->host &&
page->mapping->host == inode) {
ret = 1;
*file_offset_ret = page_offset(page) + bvec.bv_offset +
disk_bytenr - cur;
break;
}
}
return ret;
}
/*
* Lookup the checksum for the read bio in csum tree.
*
* Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise.
*/
blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio)
{
struct btrfs_inode *inode = bbio->inode;
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct extent_io_tree *io_tree = &inode->io_tree;
struct bio *bio = &bbio->bio;
struct btrfs_path *path;
const u32 sectorsize = fs_info->sectorsize;
const u32 csum_size = fs_info->csum_size;
u32 orig_len = bio->bi_iter.bi_size;
u64 orig_disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT;
u64 cur_disk_bytenr;
const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits;
int count = 0;
blk_status_t ret = BLK_STS_OK;
if ((inode->flags & BTRFS_INODE_NODATASUM) ||
test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state))
return BLK_STS_OK;
/*
* This function is only called for read bio.
*
* This means two things:
* - All our csums should only be in csum tree
* No ordered extents csums, as ordered extents are only for write
* path.
* - No need to bother any other info from bvec
* Since we're looking up csums, the only important info is the
* disk_bytenr and the length, which can be extracted from bi_iter
* directly.
*/
ASSERT(bio_op(bio) == REQ_OP_READ);
path = btrfs_alloc_path();
if (!path)
return BLK_STS_RESOURCE;
if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
bbio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS);
if (!bbio->csum) {
btrfs_free_path(path);
return BLK_STS_RESOURCE;
}
} else {
bbio->csum = bbio->csum_inline;
}
/*
* If requested number of sectors is larger than one leaf can contain,
* kick the readahead for csum tree.
*/
if (nblocks > fs_info->csums_per_leaf)
path->reada = READA_FORWARD;
/*
* the free space stuff is only read when it hasn't been
* updated in the current transaction. So, we can safely
* read from the commit root and sidestep a nasty deadlock
* between reading the free space cache and updating the csum tree.
*/
if (btrfs_is_free_space_inode(inode)) {
path->search_commit_root = 1;
path->skip_locking = 1;
}
for (cur_disk_bytenr = orig_disk_bytenr;
cur_disk_bytenr < orig_disk_bytenr + orig_len;
cur_disk_bytenr += (count * sectorsize)) {
u64 search_len = orig_disk_bytenr + orig_len - cur_disk_bytenr;
unsigned int sector_offset;
u8 *csum_dst;
/*
* Although both cur_disk_bytenr and orig_disk_bytenr is u64,
* we're calculating the offset to the bio start.
*
* Bio size is limited to UINT_MAX, thus unsigned int is large
* enough to contain the raw result, not to mention the right
* shifted result.
*/
ASSERT(cur_disk_bytenr - orig_disk_bytenr < UINT_MAX);
sector_offset = (cur_disk_bytenr - orig_disk_bytenr) >>
fs_info->sectorsize_bits;
csum_dst = bbio->csum + sector_offset * csum_size;
count = search_csum_tree(fs_info, path, cur_disk_bytenr,
search_len, csum_dst);
if (count < 0) {
ret = errno_to_blk_status(count);
if (bbio->csum != bbio->csum_inline)
kfree(bbio->csum);
bbio->csum = NULL;
break;
}
/*
* We didn't find a csum for this range. We need to make sure
* we complain loudly about this, because we are not NODATASUM.
*
* However for the DATA_RELOC inode we could potentially be
* relocating data extents for a NODATASUM inode, so the inode
* itself won't be marked with NODATASUM, but the extent we're
* copying is in fact NODATASUM. If we don't find a csum we
* assume this is the case.
*/
if (count == 0) {
memset(csum_dst, 0, csum_size);
count = 1;
if (inode->root->root_key.objectid ==
BTRFS_DATA_RELOC_TREE_OBJECTID) {
u64 file_offset;
int ret;
ret = search_file_offset_in_bio(bio,
&inode->vfs_inode,
cur_disk_bytenr, &file_offset);
if (ret)
set_extent_bits(io_tree, file_offset,
file_offset + sectorsize - 1,
EXTENT_NODATASUM);
} else {
btrfs_warn_rl(fs_info,
"csum hole found for disk bytenr range [%llu, %llu)",
cur_disk_bytenr, cur_disk_bytenr + sectorsize);
}
}
}
btrfs_free_path(path);
return ret;
}
int btrfs_lookup_csums_list(struct btrfs_root *root, u64 start, u64 end,
struct list_head *list, int search_commit,
bool nowait)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key key;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_ordered_sum *sums;
struct btrfs_csum_item *item;
LIST_HEAD(tmplist);
int ret;
ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
IS_ALIGNED(end + 1, fs_info->sectorsize));
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->nowait = nowait;
if (search_commit) {
path->skip_locking = 1;
path->reada = READA_FORWARD;
path->search_commit_root = 1;
}
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);
/*
* There are two cases we can hit here for the previous csum
* item:
*
* |<- search range ->|
* |<- csum item ->|
*
* Or
* |<- search range ->|
* |<- csum item ->|
*
* Check if the previous csum item covers the leading part of
* the search range. If so we have to start from previous csum
* item.
*/
if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
key.type == BTRFS_EXTENT_CSUM_KEY) {
if (bytes_to_csum_size(fs_info, start - key.offset) <
btrfs_item_size(leaf, path->slots[0] - 1))
path->slots[0]--;
}
}
while (start <= end) {
u64 csum_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 ||
key.offset > end)
break;
if (key.offset > start)
start = key.offset;
csum_end = key.offset + csum_size_to_bytes(fs_info,
btrfs_item_size(leaf, path->slots[0]));
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) {
unsigned long offset;
size_t size;
size = min_t(size_t, csum_end - start,
max_ordered_sum_bytes(fs_info));
sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
GFP_NOFS);
if (!sums) {
ret = -ENOMEM;
goto fail;
}
sums->bytenr = start;
sums->len = (int)size;
offset = bytes_to_csum_size(fs_info, start - key.offset);
read_extent_buffer(path->nodes[0],
sums->sums,
((unsigned long)item) + offset,
bytes_to_csum_size(fs_info, size));
start += size;
list_add_tail(&sums->list, &tmplist);
}
path->slots[0]++;
}
ret = 0;
fail:
while (ret < 0 && !list_empty(&tmplist)) {
sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
list_del(&sums->list);
kfree(sums);
}
list_splice_tail(&tmplist, list);
btrfs_free_path(path);
return ret;
}
/*
* Do the same work as btrfs_lookup_csums_list(), the difference is in how
* we return the result.
*
* This version will set the corresponding bits in @csum_bitmap to represent
* that there is a csum found.
* Each bit represents a sector. Thus caller should ensure @csum_buf passed
* in is large enough to contain all csums.
*/
int btrfs_lookup_csums_bitmap(struct btrfs_root *root, u64 start, u64 end,
u8 *csum_buf, unsigned long *csum_bitmap)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key key;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_csum_item *item;
const u64 orig_start = start;
int ret;
ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
IS_ALIGNED(end + 1, fs_info->sectorsize));
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = start;
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);
/*
* There are two cases we can hit here for the previous csum
* item:
*
* |<- search range ->|
* |<- csum item ->|
*
* Or
* |<- search range ->|
* |<- csum item ->|
*
* Check if the previous csum item covers the leading part of
* the search range. If so we have to start from previous csum
* item.
*/
if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
key.type == BTRFS_EXTENT_CSUM_KEY) {
if (bytes_to_csum_size(fs_info, start - key.offset) <
btrfs_item_size(leaf, path->slots[0] - 1))
path->slots[0]--;
}
}
while (start <= end) {
u64 csum_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 ||
key.offset > end)
break;
if (key.offset > start)
start = key.offset;
csum_end = key.offset + csum_size_to_bytes(fs_info,
btrfs_item_size(leaf, path->slots[0]));
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) {
unsigned long offset;
size_t size;
u8 *csum_dest = csum_buf + bytes_to_csum_size(fs_info,
start - orig_start);
size = min_t(size_t, csum_end - start, end + 1 - start);
offset = bytes_to_csum_size(fs_info, start - key.offset);
read_extent_buffer(path->nodes[0], csum_dest,
((unsigned long)item) + offset,
bytes_to_csum_size(fs_info, size));
bitmap_set(csum_bitmap,
(start - orig_start) >> fs_info->sectorsize_bits,
size >> fs_info->sectorsize_bits);
start += size;
}
path->slots[0]++;
}
ret = 0;
fail:
btrfs_free_path(path);
return ret;
}
/*
* Calculate checksums of the data contained inside a bio.
*/
blk_status_t btrfs_csum_one_bio(struct btrfs_bio *bbio)
{
struct btrfs_inode *inode = bbio->inode;
struct btrfs_fs_info *fs_info = inode->root->fs_info;
SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
struct bio *bio = &bbio->bio;
u64 offset = bbio->file_offset;
struct btrfs_ordered_sum *sums;
struct btrfs_ordered_extent *ordered = NULL;
char *data;
struct bvec_iter iter;
struct bio_vec bvec;
int index;
unsigned int blockcount;
unsigned long total_bytes = 0;
unsigned long this_sum_bytes = 0;
int i;
unsigned nofs_flag;
nofs_flag = memalloc_nofs_save();
sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
GFP_KERNEL);
memalloc_nofs_restore(nofs_flag);
if (!sums)
return BLK_STS_RESOURCE;
sums->len = bio->bi_iter.bi_size;
INIT_LIST_HEAD(&sums->list);
sums->bytenr = bio->bi_iter.bi_sector << 9;
index = 0;
shash->tfm = fs_info->csum_shash;
bio_for_each_segment(bvec, bio, iter) {
if (!ordered) {
ordered = btrfs_lookup_ordered_extent(inode, offset);
/*
* The bio range is not covered by any ordered extent,
* must be a code logic error.
*/
if (unlikely(!ordered)) {
WARN(1, KERN_WARNING
"no ordered extent for root %llu ino %llu offset %llu\n",
inode->root->root_key.objectid,
btrfs_ino(inode), offset);
kvfree(sums);
return BLK_STS_IOERR;
}
}
blockcount = BTRFS_BYTES_TO_BLKS(fs_info,
bvec.bv_len + fs_info->sectorsize
- 1);
for (i = 0; i < blockcount; i++) {
if (!(bio->bi_opf & REQ_BTRFS_ONE_ORDERED) &&
!in_range(offset, ordered->file_offset,
ordered->num_bytes)) {
unsigned long bytes_left;
sums->len = this_sum_bytes;
this_sum_bytes = 0;
btrfs_add_ordered_sum(ordered, sums);
btrfs_put_ordered_extent(ordered);
bytes_left = bio->bi_iter.bi_size - total_bytes;
nofs_flag = memalloc_nofs_save();
sums = kvzalloc(btrfs_ordered_sum_size(fs_info,
bytes_left), GFP_KERNEL);
memalloc_nofs_restore(nofs_flag);
BUG_ON(!sums); /* -ENOMEM */
sums->len = bytes_left;
ordered = btrfs_lookup_ordered_extent(inode,
offset);
ASSERT(ordered); /* Logic error */
sums->bytenr = (bio->bi_iter.bi_sector << 9)
+ total_bytes;
index = 0;
}
data = bvec_kmap_local(&bvec);
crypto_shash_digest(shash,
data + (i * fs_info->sectorsize),
fs_info->sectorsize,
sums->sums + index);
kunmap_local(data);
index += fs_info->csum_size;
offset += fs_info->sectorsize;
this_sum_bytes += fs_info->sectorsize;
total_bytes += fs_info->sectorsize;
}
}
this_sum_bytes = 0;
btrfs_add_ordered_sum(ordered, sums);
btrfs_put_ordered_extent(ordered);
return 0;
}
/*
* Remove one checksum overlapping a range.
*
* 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 void truncate_one_csum(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
struct btrfs_key *key,
u64 bytenr, u64 len)
{
struct extent_buffer *leaf;
const u32 csum_size = fs_info->csum_size;
u64 csum_end;
u64 end_byte = bytenr + len;
u32 blocksize_bits = fs_info->sectorsize_bits;
leaf = path->nodes[0];
csum_end = btrfs_item_size(leaf, path->slots[0]) / csum_size;
csum_end <<= 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;
btrfs_truncate_item(path, new_size, 1);
} 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;
btrfs_truncate_item(path, new_size, 0);
key->offset = end_byte;
btrfs_set_item_key_safe(fs_info, path, key);
} else {
BUG();
}
}
/*
* Delete 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_fs_info *fs_info = trans->fs_info;
struct btrfs_path *path;
struct btrfs_key key;
u64 end_byte = bytenr + len;
u64 csum_end;
struct extent_buffer *leaf;
int ret = 0;
const u32 csum_size = fs_info->csum_size;
u32 blocksize_bits = fs_info->sectorsize_bits;
ASSERT(root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID ||
root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while (1) {
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.offset = end_byte - 1;
key.type = BTRFS_EXTENT_CSUM_KEY;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
ret = 0;
if (path->slots[0] == 0)
break;
path->slots[0]--;
} else 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;
}
if (key.offset >= end_byte)
break;
csum_end = btrfs_item_size(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) {
int del_nr = 1;
/*
* Check how many csum items preceding this one in this
* leaf correspond to our range and then delete them all
* at once.
*/
if (key.offset > bytenr && path->slots[0] > 0) {
int slot = path->slots[0] - 1;
while (slot >= 0) {
struct btrfs_key pk;
btrfs_item_key_to_cpu(leaf, &pk, slot);
if (pk.offset < bytenr ||
pk.type != BTRFS_EXTENT_CSUM_KEY ||
pk.objectid !=
BTRFS_EXTENT_CSUM_OBJECTID)
break;
path->slots[0] = slot;
del_nr++;
key.offset = pk.offset;
slot--;
}
}
ret = btrfs_del_items(trans, root, path,
path->slots[0], del_nr);
if (ret)
break;
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]);
memzero_extent_buffer(leaf, 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);
if (ret && ret != -EAGAIN) {
btrfs_abort_transaction(trans, ret);
break;
}
ret = 0;
key.offset = end_byte - 1;
} else {
truncate_one_csum(fs_info, path, &key, bytenr, len);
if (key.offset < bytenr)
break;
}
btrfs_release_path(path);
}
btrfs_free_path(path);
return ret;
}
static int find_next_csum_offset(struct btrfs_root *root,
struct btrfs_path *path,
u64 *next_offset)
{
const u32 nritems = btrfs_header_nritems(path->nodes[0]);
struct btrfs_key found_key;
int slot = path->slots[0] + 1;
int ret;
if (nritems == 0 || slot >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
return ret;
} else if (ret > 0) {
*next_offset = (u64)-1;
return 0;
}
slot = path->slots[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)
*next_offset = (u64)-1;
else
*next_offset = found_key.offset;
return 0;
}
int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_ordered_sum *sums)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key file_key;
struct btrfs_key found_key;
struct btrfs_path *path;
struct btrfs_csum_item *item;
struct btrfs_csum_item *item_end;
struct extent_buffer *leaf = NULL;
u64 next_offset;
u64 total_bytes = 0;
u64 csum_offset;
u64 bytenr;
u32 ins_size;
int index = 0;
int found_next;
int ret;
const u32 csum_size = fs_info->csum_size;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
again:
next_offset = (u64)-1;
found_next = 0;
bytenr = sums->bytenr + total_bytes;
file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
file_key.offset = bytenr;
file_key.type = BTRFS_EXTENT_CSUM_KEY;
item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
if (!IS_ERR(item)) {
ret = 0;
leaf = path->nodes[0];
item_end = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_csum_item);
item_end = (struct btrfs_csum_item *)((char *)item_end +
btrfs_item_size(leaf, path->slots[0]));
goto found;
}
ret = PTR_ERR(item);
if (ret != -EFBIG && ret != -ENOENT)
goto out;
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(leaf, path->slots[0]);
if ((item_size / csum_size) >=
MAX_CSUM_ITEMS(fs_info, csum_size)) {
/* already at max size, make a new one */
goto insert;
}
} else {
/* We didn't find a csum item, insert one. */
ret = find_next_csum_offset(root, path, &next_offset);
if (ret < 0)
goto out;
found_next = 1;
goto insert;
}
/*
* At this point, we know the tree has a checksum item that ends at an
* offset matching the start of the checksum range we want to insert.
* We try to extend that item as much as possible and then add as many
* checksums to it as they fit.
*
* First check if the leaf has enough free space for at least one
* checksum. If it has go directly to the item extension code, otherwise
* release the path and do a search for insertion before the extension.
*/
if (btrfs_leaf_free_space(leaf) >= csum_size) {
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
csum_offset = (bytenr - found_key.offset) >>
fs_info->sectorsize_bits;
goto extend_csum;
}
btrfs_release_path(path);
path->search_for_extension = 1;
ret = btrfs_search_slot(trans, root, &file_key, path,
csum_size, 1);
path->search_for_extension = 0;
if (ret < 0)
goto out;
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) >> fs_info->sectorsize_bits;
if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
goto insert;
}
extend_csum:
if (csum_offset == btrfs_item_size(leaf, path->slots[0]) /
csum_size) {
int extend_nr;
u64 tmp;
u32 diff;
tmp = sums->len - total_bytes;
tmp >>= fs_info->sectorsize_bits;
WARN_ON(tmp < 1);
extend_nr = max_t(int, 1, tmp);
/*
* A log tree can already have checksum items with a subset of
* the checksums we are trying to log. This can happen after
* doing a sequence of partial writes into prealloc extents and
* fsyncs in between, with a full fsync logging a larger subrange
* of an extent for which a previous fast fsync logged a smaller
* subrange. And this happens in particular due to merging file
* extent items when we complete an ordered extent for a range
* covered by a prealloc extent - this is done at
* btrfs_mark_extent_written().
*
* So if we try to extend the previous checksum item, which has
* a range that ends at the start of the range we want to insert,
* make sure we don't extend beyond the start offset of the next
* checksum item. If we are at the last item in the leaf, then
* forget the optimization of extending and add a new checksum
* item - it is not worth the complexity of releasing the path,
* getting the first key for the next leaf, repeat the btree
* search, etc, because log trees are temporary anyway and it
* would only save a few bytes of leaf space.
*/
if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
if (path->slots[0] + 1 >=
btrfs_header_nritems(path->nodes[0])) {
ret = find_next_csum_offset(root, path, &next_offset);
if (ret < 0)
goto out;
found_next = 1;
goto insert;
}
ret = find_next_csum_offset(root, path, &next_offset);
if (ret < 0)
goto out;
tmp = (next_offset - bytenr) >> fs_info->sectorsize_bits;
if (tmp <= INT_MAX)
extend_nr = min_t(int, extend_nr, tmp);
}
diff = (csum_offset + extend_nr) * csum_size;
diff = min(diff,
MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
diff = diff - btrfs_item_size(leaf, path->slots[0]);
diff = min_t(u32, btrfs_leaf_free_space(leaf), diff);
diff /= csum_size;
diff *= csum_size;
btrfs_extend_item(path, diff);
ret = 0;
goto csum;
}
insert:
btrfs_release_path(path);
csum_offset = 0;
if (found_next) {
u64 tmp;
tmp = sums->len - total_bytes;
tmp >>= fs_info->sectorsize_bits;
tmp = min(tmp, (next_offset - file_key.offset) >>
fs_info->sectorsize_bits);
tmp = max_t(u64, 1, tmp);
tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
ins_size = csum_size * tmp;
} else {
ins_size = csum_size;
}
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
ins_size);
if (ret < 0)
goto out;
if (WARN_ON(ret != 0))
goto out;
leaf = path->nodes[0];
csum:
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
item_end = (struct btrfs_csum_item *)((unsigned char *)item +
btrfs_item_size(leaf, path->slots[0]));
item = (struct btrfs_csum_item *)((unsigned char *)item +
csum_offset * csum_size);
found:
ins_size = (u32)(sums->len - total_bytes) >> fs_info->sectorsize_bits;
ins_size *= csum_size;
ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
ins_size);
write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
ins_size);
index += ins_size;
ins_size /= csum_size;
total_bytes += ins_size * fs_info->sectorsize;
btrfs_mark_buffer_dirty(path->nodes[0]);
if (total_bytes < sums->len) {
btrfs_release_path(path);
cond_resched();
goto again;
}
out:
btrfs_free_path(path);
return ret;
}
void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
const struct btrfs_path *path,
struct btrfs_file_extent_item *fi,
struct extent_map *em)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct btrfs_root *root = inode->root;
struct extent_buffer *leaf = path->nodes[0];
const int slot = path->slots[0];
struct btrfs_key key;
u64 extent_start, extent_end;
u64 bytenr;
u8 type = btrfs_file_extent_type(leaf, fi);
int compress_type = btrfs_file_extent_compression(leaf, fi);
btrfs_item_key_to_cpu(leaf, &key, slot);
extent_start = key.offset;
extent_end = btrfs_file_extent_end(path);
em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
em->generation = btrfs_file_extent_generation(leaf, fi);
if (type == BTRFS_FILE_EXTENT_REG ||
type == BTRFS_FILE_EXTENT_PREALLOC) {
em->start = extent_start;
em->len = extent_end - extent_start;
em->orig_start = extent_start -
btrfs_file_extent_offset(leaf, fi);
em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
if (bytenr == 0) {
em->block_start = EXTENT_MAP_HOLE;
return;
}
if (compress_type != BTRFS_COMPRESS_NONE) {
set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
em->compress_type = compress_type;
em->block_start = bytenr;
em->block_len = em->orig_block_len;
} else {
bytenr += btrfs_file_extent_offset(leaf, fi);
em->block_start = bytenr;
em->block_len = em->len;
if (type == BTRFS_FILE_EXTENT_PREALLOC)
set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
}
} else if (type == BTRFS_FILE_EXTENT_INLINE) {
em->block_start = EXTENT_MAP_INLINE;
em->start = extent_start;
em->len = extent_end - extent_start;
/*
* Initialize orig_start and block_len with the same values
* as in inode.c:btrfs_get_extent().
*/
em->orig_start = EXTENT_MAP_HOLE;
em->block_len = (u64)-1;
em->compress_type = compress_type;
if (compress_type != BTRFS_COMPRESS_NONE)
set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
} else {
btrfs_err(fs_info,
"unknown file extent item type %d, inode %llu, offset %llu, "
"root %llu", type, btrfs_ino(inode), extent_start,
root->root_key.objectid);
}
}
/*
* Returns the end offset (non inclusive) of the file extent item the given path
* points to. If it points to an inline extent, the returned offset is rounded
* up to the sector size.
*/
u64 btrfs_file_extent_end(const struct btrfs_path *path)
{
const struct extent_buffer *leaf = path->nodes[0];
const int slot = path->slots[0];
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
u64 end;
btrfs_item_key_to_cpu(leaf, &key, slot);
ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
end = btrfs_file_extent_ram_bytes(leaf, fi);
end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
} else {
end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
}
return end;
}
Ссылка в новой задаче Показать git blame Копировать постоянную ссылку