![Chris Mason](/assets/img/avatar_default.png)
This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
586 lines
16 KiB
C
586 lines
16 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/bio.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "print-tree.h"
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#define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
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sizeof(struct btrfs_item) * 2) / \
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BTRFS_CRC32_SIZE) - 1))
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int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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u64 objectid, u64 pos,
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u64 disk_offset, u64 disk_num_bytes,
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u64 num_bytes, u64 offset, u64 ram_bytes,
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u8 compression, u8 encryption, u16 other_encoding)
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{
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int ret = 0;
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struct btrfs_file_extent_item *item;
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struct btrfs_key file_key;
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struct btrfs_path *path;
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struct extent_buffer *leaf;
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path = btrfs_alloc_path();
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BUG_ON(!path);
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file_key.objectid = objectid;
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file_key.offset = pos;
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btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
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ret = btrfs_insert_empty_item(trans, root, path, &file_key,
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sizeof(*item));
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if (ret < 0)
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goto out;
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BUG_ON(ret);
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leaf = path->nodes[0];
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item = btrfs_item_ptr(leaf, path->slots[0],
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struct btrfs_file_extent_item);
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btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
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btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
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btrfs_set_file_extent_offset(leaf, item, offset);
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btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
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btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
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btrfs_set_file_extent_generation(leaf, item, trans->transid);
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btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
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btrfs_set_file_extent_compression(leaf, item, compression);
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btrfs_set_file_extent_encryption(leaf, item, encryption);
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btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
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btrfs_mark_buffer_dirty(leaf);
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out:
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btrfs_free_path(path);
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return ret;
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}
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struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path,
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u64 objectid, u64 offset,
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int cow)
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{
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int ret;
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struct btrfs_key file_key;
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struct btrfs_key found_key;
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struct btrfs_csum_item *item;
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struct extent_buffer *leaf;
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u64 csum_offset = 0;
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int csums_in_item;
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file_key.objectid = objectid;
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file_key.offset = offset;
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btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
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ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
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if (ret < 0)
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goto fail;
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leaf = path->nodes[0];
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if (ret > 0) {
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ret = 1;
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if (path->slots[0] == 0)
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goto fail;
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path->slots[0]--;
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btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
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if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
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found_key.objectid != objectid) {
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goto fail;
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}
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csum_offset = (offset - found_key.offset) >>
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root->fs_info->sb->s_blocksize_bits;
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csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
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csums_in_item /= BTRFS_CRC32_SIZE;
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if (csum_offset >= csums_in_item) {
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ret = -EFBIG;
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goto fail;
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}
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}
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item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
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item = (struct btrfs_csum_item *)((unsigned char *)item +
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csum_offset * BTRFS_CRC32_SIZE);
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return item;
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fail:
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if (ret > 0)
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ret = -ENOENT;
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return ERR_PTR(ret);
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}
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int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, u64 objectid,
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u64 offset, int mod)
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{
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int ret;
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struct btrfs_key file_key;
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int ins_len = mod < 0 ? -1 : 0;
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int cow = mod != 0;
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file_key.objectid = objectid;
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file_key.offset = offset;
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btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
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ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
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return ret;
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}
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int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
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struct bio *bio)
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{
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u32 sum;
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struct bio_vec *bvec = bio->bi_io_vec;
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int bio_index = 0;
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u64 offset;
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u64 item_start_offset = 0;
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u64 item_last_offset = 0;
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u32 diff;
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int ret;
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struct btrfs_path *path;
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struct btrfs_csum_item *item = NULL;
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struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
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path = btrfs_alloc_path();
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if (bio->bi_size > PAGE_CACHE_SIZE * 8)
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path->reada = 2;
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WARN_ON(bio->bi_vcnt <= 0);
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while(bio_index < bio->bi_vcnt) {
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offset = page_offset(bvec->bv_page) + bvec->bv_offset;
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ret = btrfs_find_ordered_sum(inode, offset, &sum);
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if (ret == 0)
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goto found;
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if (!item || offset < item_start_offset ||
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offset >= item_last_offset) {
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struct btrfs_key found_key;
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u32 item_size;
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if (item)
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btrfs_release_path(root, path);
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item = btrfs_lookup_csum(NULL, root, path,
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inode->i_ino, offset, 0);
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if (IS_ERR(item)) {
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ret = PTR_ERR(item);
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if (ret == -ENOENT || ret == -EFBIG)
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ret = 0;
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sum = 0;
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printk("no csum found for inode %lu start "
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"%llu\n", inode->i_ino,
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(unsigned long long)offset);
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item = NULL;
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goto found;
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}
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btrfs_item_key_to_cpu(path->nodes[0], &found_key,
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path->slots[0]);
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item_start_offset = found_key.offset;
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item_size = btrfs_item_size_nr(path->nodes[0],
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path->slots[0]);
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item_last_offset = item_start_offset +
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(item_size / BTRFS_CRC32_SIZE) *
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root->sectorsize;
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item = btrfs_item_ptr(path->nodes[0], path->slots[0],
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struct btrfs_csum_item);
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}
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/*
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* this byte range must be able to fit inside
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* a single leaf so it will also fit inside a u32
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*/
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diff = offset - item_start_offset;
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diff = diff / root->sectorsize;
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diff = diff * BTRFS_CRC32_SIZE;
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read_extent_buffer(path->nodes[0], &sum,
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((unsigned long)item) + diff,
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BTRFS_CRC32_SIZE);
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found:
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set_state_private(io_tree, offset, sum);
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bio_index++;
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bvec++;
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}
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btrfs_free_path(path);
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return 0;
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}
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int btrfs_csum_file_bytes(struct btrfs_root *root, struct inode *inode,
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u64 start, unsigned long len)
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{
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struct btrfs_ordered_sum *sums;
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struct btrfs_sector_sum *sector_sum;
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struct btrfs_ordered_extent *ordered;
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char *data;
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struct page *page;
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unsigned long total_bytes = 0;
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unsigned long this_sum_bytes = 0;
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sums = kzalloc(btrfs_ordered_sum_size(root, len), GFP_NOFS);
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if (!sums)
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return -ENOMEM;
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sector_sum = sums->sums;
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sums->file_offset = start;
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sums->len = len;
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INIT_LIST_HEAD(&sums->list);
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ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);
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BUG_ON(!ordered);
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while(len > 0) {
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if (start >= ordered->file_offset + ordered->len ||
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start < ordered->file_offset) {
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sums->len = this_sum_bytes;
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this_sum_bytes = 0;
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btrfs_add_ordered_sum(inode, ordered, sums);
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btrfs_put_ordered_extent(ordered);
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sums = kzalloc(btrfs_ordered_sum_size(root, len),
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GFP_NOFS);
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BUG_ON(!sums);
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sector_sum = sums->sums;
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sums->len = len;
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sums->file_offset = start;
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ordered = btrfs_lookup_ordered_extent(inode,
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sums->file_offset);
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BUG_ON(!ordered);
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}
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page = find_get_page(inode->i_mapping,
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start >> PAGE_CACHE_SHIFT);
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data = kmap_atomic(page, KM_USER0);
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sector_sum->sum = ~(u32)0;
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sector_sum->sum = btrfs_csum_data(root, data, sector_sum->sum,
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PAGE_CACHE_SIZE);
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kunmap_atomic(data, KM_USER0);
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btrfs_csum_final(sector_sum->sum,
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(char *)§or_sum->sum);
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sector_sum->offset = page_offset(page);
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page_cache_release(page);
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sector_sum++;
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total_bytes += PAGE_CACHE_SIZE;
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this_sum_bytes += PAGE_CACHE_SIZE;
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start += PAGE_CACHE_SIZE;
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WARN_ON(len < PAGE_CACHE_SIZE);
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len -= PAGE_CACHE_SIZE;
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}
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btrfs_add_ordered_sum(inode, ordered, sums);
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btrfs_put_ordered_extent(ordered);
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return 0;
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}
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int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
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struct bio *bio)
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{
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struct btrfs_ordered_sum *sums;
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struct btrfs_sector_sum *sector_sum;
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struct btrfs_ordered_extent *ordered;
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char *data;
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struct bio_vec *bvec = bio->bi_io_vec;
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int bio_index = 0;
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unsigned long total_bytes = 0;
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unsigned long this_sum_bytes = 0;
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u64 offset;
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WARN_ON(bio->bi_vcnt <= 0);
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sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
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if (!sums)
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return -ENOMEM;
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sector_sum = sums->sums;
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sums->file_offset = page_offset(bvec->bv_page) + bvec->bv_offset;
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sums->len = bio->bi_size;
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INIT_LIST_HEAD(&sums->list);
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ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);
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BUG_ON(!ordered);
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while(bio_index < bio->bi_vcnt) {
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offset = page_offset(bvec->bv_page) + bvec->bv_offset;
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if (offset >= ordered->file_offset + ordered->len ||
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offset < ordered->file_offset) {
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unsigned long bytes_left;
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sums->len = this_sum_bytes;
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this_sum_bytes = 0;
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btrfs_add_ordered_sum(inode, ordered, sums);
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btrfs_put_ordered_extent(ordered);
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bytes_left = bio->bi_size - total_bytes;
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sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
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GFP_NOFS);
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BUG_ON(!sums);
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sector_sum = sums->sums;
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sums->len = bytes_left;
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sums->file_offset = offset;
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ordered = btrfs_lookup_ordered_extent(inode,
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sums->file_offset);
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BUG_ON(!ordered);
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}
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data = kmap_atomic(bvec->bv_page, KM_USER0);
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sector_sum->sum = ~(u32)0;
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sector_sum->sum = btrfs_csum_data(root,
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data + bvec->bv_offset,
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sector_sum->sum,
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bvec->bv_len);
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kunmap_atomic(data, KM_USER0);
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btrfs_csum_final(sector_sum->sum,
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(char *)§or_sum->sum);
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sector_sum->offset = page_offset(bvec->bv_page) +
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bvec->bv_offset;
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sector_sum++;
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bio_index++;
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total_bytes += bvec->bv_len;
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this_sum_bytes += bvec->bv_len;
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bvec++;
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}
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this_sum_bytes = 0;
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btrfs_add_ordered_sum(inode, ordered, sums);
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btrfs_put_ordered_extent(ordered);
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return 0;
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}
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int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct inode *inode,
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struct btrfs_ordered_sum *sums)
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{
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u64 objectid = inode->i_ino;
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u64 offset;
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int ret;
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struct btrfs_key file_key;
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struct btrfs_key found_key;
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u64 next_offset;
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u64 total_bytes = 0;
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int found_next;
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struct btrfs_path *path;
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struct btrfs_csum_item *item;
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struct btrfs_csum_item *item_end;
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struct extent_buffer *leaf = NULL;
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u64 csum_offset;
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struct btrfs_sector_sum *sector_sum;
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u32 nritems;
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u32 ins_size;
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char *eb_map;
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char *eb_token;
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unsigned long map_len;
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unsigned long map_start;
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path = btrfs_alloc_path();
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BUG_ON(!path);
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sector_sum = sums->sums;
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again:
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next_offset = (u64)-1;
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found_next = 0;
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offset = sector_sum->offset;
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file_key.objectid = objectid;
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file_key.offset = offset;
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btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
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mutex_lock(&BTRFS_I(inode)->csum_mutex);
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item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
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if (!IS_ERR(item)) {
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leaf = path->nodes[0];
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ret = 0;
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goto found;
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}
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ret = PTR_ERR(item);
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if (ret == -EFBIG) {
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u32 item_size;
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/* we found one, but it isn't big enough yet */
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leaf = path->nodes[0];
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item_size = btrfs_item_size_nr(leaf, path->slots[0]);
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if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
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/* already at max size, make a new one */
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goto insert;
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}
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} else {
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int slot = path->slots[0] + 1;
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/* we didn't find a csum item, insert one */
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nritems = btrfs_header_nritems(path->nodes[0]);
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if (path->slots[0] >= nritems - 1) {
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ret = btrfs_next_leaf(root, path);
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if (ret == 1)
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found_next = 1;
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if (ret != 0)
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goto insert;
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slot = 0;
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}
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btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
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if (found_key.objectid != objectid ||
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found_key.type != BTRFS_CSUM_ITEM_KEY) {
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found_next = 1;
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goto insert;
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}
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next_offset = found_key.offset;
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found_next = 1;
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goto insert;
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}
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/*
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* at this point, we know the tree has an item, but it isn't big
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* enough yet to put our csum in. Grow it
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*/
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btrfs_release_path(root, path);
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ret = btrfs_search_slot(trans, root, &file_key, path,
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|
BTRFS_CRC32_SIZE, 1);
|
|
if (ret < 0)
|
|
goto fail_unlock;
|
|
if (ret == 0) {
|
|
BUG();
|
|
}
|
|
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 = (offset - found_key.offset) >>
|
|
root->fs_info->sb->s_blocksize_bits;
|
|
if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
|
|
found_key.objectid != objectid ||
|
|
csum_offset >= MAX_CSUM_ITEMS(root)) {
|
|
goto insert;
|
|
}
|
|
if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
|
|
BTRFS_CRC32_SIZE) {
|
|
u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
|
|
diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
|
|
if (diff != BTRFS_CRC32_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 = min((u64)i_size_read(inode), next_offset);
|
|
tmp -= offset & ~((u64)root->sectorsize -1);
|
|
tmp >>= root->fs_info->sb->s_blocksize_bits;
|
|
tmp = max((u64)1, tmp);
|
|
tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
|
|
ins_size = BTRFS_CRC32_SIZE * tmp;
|
|
} else {
|
|
ins_size = BTRFS_CRC32_SIZE;
|
|
}
|
|
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
|
|
ins_size);
|
|
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 * BTRFS_CRC32_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;
|
|
mutex_unlock(&BTRFS_I(inode)->csum_mutex);
|
|
cond_resched();
|
|
next_sector:
|
|
|
|
if (!eb_token ||
|
|
(unsigned long)item + BTRFS_CRC32_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,
|
|
BTRFS_CRC32_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)),
|
|
§or_sum->sum, BTRFS_CRC32_SIZE);
|
|
} else {
|
|
write_extent_buffer(leaf, §or_sum->sum,
|
|
(unsigned long)item, BTRFS_CRC32_SIZE);
|
|
}
|
|
|
|
total_bytes += root->sectorsize;
|
|
sector_sum++;
|
|
if (total_bytes < sums->len) {
|
|
item = (struct btrfs_csum_item *)((char *)item +
|
|
BTRFS_CRC32_SIZE);
|
|
if (item < item_end && offset + PAGE_CACHE_SIZE ==
|
|
sector_sum->offset) {
|
|
offset = sector_sum->offset;
|
|
goto next_sector;
|
|
}
|
|
}
|
|
if (eb_token) {
|
|
unmap_extent_buffer(leaf, eb_token, KM_USER1);
|
|
eb_token = NULL;
|
|
}
|
|
btrfs_mark_buffer_dirty(path->nodes[0]);
|
|
cond_resched();
|
|
if (total_bytes < sums->len) {
|
|
btrfs_release_path(root, path);
|
|
goto again;
|
|
}
|
|
out:
|
|
btrfs_free_path(path);
|
|
return ret;
|
|
|
|
fail_unlock:
|
|
mutex_unlock(&BTRFS_I(inode)->csum_mutex);
|
|
goto out;
|
|
}
|
|
|
|
int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct btrfs_path *path,
|
|
u64 isize)
|
|
{
|
|
struct btrfs_key key;
|
|
struct extent_buffer *leaf = path->nodes[0];
|
|
int slot = path->slots[0];
|
|
int ret;
|
|
u32 new_item_size;
|
|
u64 new_item_span;
|
|
u64 blocks;
|
|
|
|
btrfs_item_key_to_cpu(leaf, &key, slot);
|
|
if (isize <= key.offset)
|
|
return 0;
|
|
new_item_span = isize - key.offset;
|
|
blocks = (new_item_span + root->sectorsize - 1) >>
|
|
root->fs_info->sb->s_blocksize_bits;
|
|
new_item_size = blocks * BTRFS_CRC32_SIZE;
|
|
if (new_item_size >= btrfs_item_size_nr(leaf, slot))
|
|
return 0;
|
|
ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
|
|
BUG_ON(ret);
|
|
return ret;
|
|
}
|