linux/fs/btrfs/file-item.c
Qu Wenruo 6275193ef1 btrfs: refactor btrfs_lookup_bio_sums to handle out-of-order bvecs
Refactor btrfs_lookup_bio_sums() by:

- Remove the @file_offset parameter
  There are two factors making the @file_offset parameter useless:

  * For csum lookup in csum tree, file offset makes no sense
    We only need disk_bytenr, which is unrelated to file_offset

  * page_offset (file offset) of each bvec is not contiguous.
    Pages can be added to the same bio as long as their on-disk bytenr
    is contiguous, meaning we could have pages at different file offsets
    in the same bio.

  Thus passing file_offset makes no sense any more.
  The only user of file_offset is for data reloc inode, we will use
  a new function, search_file_offset_in_bio(), to handle it.

- Extract the csum tree lookup into search_csum_tree()
  The new function will handle the csum search in csum tree.
  The return value is the same as btrfs_find_ordered_sum(), returning
  the number of found sectors which have checksum.

- Change how we do the main loop
  The only needed info from bio is:
  * the on-disk bytenr
  * the length

  After extracting the above info, we can do the search without bio
  at all, which makes the main loop much simpler:

	for (cur_disk_bytenr = orig_disk_bytenr;
	     cur_disk_bytenr < orig_disk_bytenr + orig_len;
	     cur_disk_bytenr += count * sectorsize) {

		/* Lookup csum tree */
		count = search_csum_tree(fs_info, path, cur_disk_bytenr,
					 search_len, csum_dst);
		if (!count) {
			/* Csum hole handling */
		}
	}

- Use single variable as the source to calculate all other offsets
  Instead of all different type of variables, we use only one main
  variable, cur_disk_bytenr, which represents the current disk bytenr.

  All involved values can be calculated from that variable, and
  all those variable will only be visible in the inner loop.

The above refactoring makes btrfs_lookup_bio_sums() way more robust than
it used to be, especially related to the file offset lookup.  Now
file_offset lookup is only related to data reloc inode, otherwise we
don't need to bother file_offset at all.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09 19:16:11 +01:00

1211 lines
34 KiB
C

// 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 "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "volumes.h"
#include "print-tree.h"
#include "compression.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))
/**
* @inode - the inode we want to update the disk_i_size for
* @new_i_size - the 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);
}
/**
* @inode - the inode we're modifying
* @start - the start file offset of the file extent we've inserted
* @len - the 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);
}
/**
* @inode - the inode we're modifying
* @start - the start file offset of the file extent we've inserted
* @len - the 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, 0, 0, NULL);
}
static inline u32 max_ordered_sum_bytes(struct btrfs_fs_info *fs_info,
u16 csum_size)
{
u32 ncsums = (PAGE_SIZE - sizeof(struct btrfs_ordered_sum)) / csum_size;
return ncsums * fs_info->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();
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, 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;
}
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_nr(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)
{
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;
file_key.type = BTRFS_EXTENT_DATA_KEY;
ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
return ret;
}
/*
* Find checksums for logical bytenr range [disk_bytenr, disk_bytenr + len) and
* estore 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_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_nr(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);
item = btrfs_lookup_csum(NULL, fs_info->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_nr(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 = 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.
*
* @inode: inode that the bio is for.
* @bio: bio to look up.
* @dst: Buffer of size nblocks * btrfs_super_csum_size() used to return
* checksum (nblocks = bio->bi_iter.bi_size / fs_info->sectorsize). If
* NULL, the checksum buffer is allocated and returned in
* btrfs_io_bio(bio)->csum instead.
*
* Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise.
*/
blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
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;
u8 *csum;
const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits;
int count = 0;
if (!fs_info->csum_root || (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
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 (!dst) {
struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio);
if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
btrfs_bio->csum = kmalloc_array(nblocks, csum_size,
GFP_NOFS);
if (!btrfs_bio->csum) {
btrfs_free_path(path);
return BLK_STS_RESOURCE;
}
} else {
btrfs_bio->csum = btrfs_bio->csum_inline;
}
csum = btrfs_bio->csum;
} else {
csum = dst;
}
/*
* 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(BTRFS_I(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 = csum + sector_offset * csum_size;
count = search_csum_tree(fs_info, path, cur_disk_bytenr,
search_len, csum_dst);
if (count <= 0) {
/*
* Either we hit a critical error or we didn't find
* the csum.
* Either way, we put zero into the csums dst, and skip
* to the next sector.
*/
memset(csum_dst, 0, csum_size);
count = 1;
/*
* For data reloc inode, we need to mark the range
* NODATASUM so that balance won't report false csum
* error.
*/
if (BTRFS_I(inode)->root->root_key.objectid ==
BTRFS_DATA_RELOC_TREE_OBJECTID) {
u64 file_offset;
int ret;
ret = search_file_offset_in_bio(bio, 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 BLK_STS_OK;
}
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
struct list_head *list, int search_commit)
{
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);
unsigned long offset;
int ret;
size_t size;
u64 csum_end;
const u32 csum_size = fs_info->csum_size;
ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
IS_ALIGNED(end + 1, fs_info->sectorsize));
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
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);
if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
key.type == BTRFS_EXTENT_CSUM_KEY) {
offset = (start - key.offset) >> fs_info->sectorsize_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 ||
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) * fs_info->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(fs_info, csum_size));
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 = (start - key.offset) >> fs_info->sectorsize_bits;
offset *= csum_size;
size >>= fs_info->sectorsize_bits;
read_extent_buffer(path->nodes[0],
sums->sums,
((unsigned long)item) + offset,
csum_size * size);
start += fs_info->sectorsize * 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;
}
/*
* btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio
* @inode: Owner of the data inside the bio
* @bio: Contains the data to be checksummed
* @file_start: offset in file this bio begins to describe
* @contig: Boolean. If true/1 means all bio vecs in this bio are
* contiguous and they begin at @file_start in the file. False/0
* means this bio can contains potentially discontigous bio vecs
* so the logical offset of each should be calculated separately.
*/
blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
u64 file_start, int contig)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
struct btrfs_ordered_sum *sums;
struct btrfs_ordered_extent *ordered = NULL;
char *data;
struct bvec_iter iter;
struct bio_vec bvec;
int index;
int nr_sectors;
unsigned long total_bytes = 0;
unsigned long this_sum_bytes = 0;
int i;
u64 offset;
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);
if (contig)
offset = file_start;
else
offset = 0; /* shut up gcc */
sums->bytenr = bio->bi_iter.bi_sector << 9;
index = 0;
shash->tfm = fs_info->csum_shash;
bio_for_each_segment(bvec, bio, iter) {
if (!contig)
offset = page_offset(bvec.bv_page) + bvec.bv_offset;
if (!ordered) {
ordered = btrfs_lookup_ordered_extent(inode, offset);
BUG_ON(!ordered); /* Logic error */
}
nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
bvec.bv_len + fs_info->sectorsize
- 1);
for (i = 0; i < nr_sectors; i++) {
if (offset >= ordered->file_offset + ordered->num_bytes ||
offset < ordered->file_offset) {
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 = kmap_atomic(bvec.bv_page);
crypto_shash_digest(shash, data + bvec.bv_offset
+ (i * fs_info->sectorsize),
fs_info->sectorsize,
sums->sums + index);
kunmap_atomic(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;
}
/*
* 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 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_nr(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();
}
}
/*
* 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_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;
const u32 csum_size = fs_info->csum_size;
u32 blocksize_bits = fs_info->sectorsize_bits;
ASSERT(root == fs_info->csum_root ||
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) {
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_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) {
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)
goto out;
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);
goto out;
}
key.offset = end_byte - 1;
} else {
truncate_one_csum(fs_info, path, &key, bytenr, len);
if (key.offset < bytenr)
break;
}
btrfs_release_path(path);
}
ret = 0;
out:
btrfs_free_path(path);
return ret;
}
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 nritems;
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_nr(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_nr(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 {
int slot = path->slots[0] + 1;
/* we didn't find a csum item, insert one */
nritems = btrfs_header_nritems(path->nodes[0]);
if (!nritems || (path->slots[0] >= nritems - 1)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
found_next = 1;
goto insert;
}
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) {
found_next = 1;
goto insert;
}
next_offset = found_key.offset;
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);
ret = btrfs_search_slot(trans, root, &file_key, path,
csum_size, 1);
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_nr(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, (int)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_nr(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_nr(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,
const bool new_inline,
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);
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;
if (!new_inline && compress_type != BTRFS_COMPRESS_NONE) {
set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
em->compress_type = compress_type;
}
} 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;
}