btrfs-progs: Introduce function to initialize fs tree

[btrfs-progs-unstable/devel.git] / file-item.c

/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include "kerncompat.h"
#include "radix-tree.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "print-tree.h"
#include "crc32c.h"
#include "internal.h"

#define MAX_CSUM_ITEMS(r,size) ((((BTRFS_LEAF_DATA_SIZE(r) - \
                               sizeof(struct btrfs_item) * 2) / \
                               size) - 1))
int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root,
                             u64 objectid, u64 pos, u64 offset,
                             u64 disk_num_bytes, 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();
        BUG_ON(!path);
        file_key.objectid = objectid;
        file_key.offset = pos;
        btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);

        ret = btrfs_insert_empty_item(trans, root, path, &file_key,
                                      sizeof(*item));
        if (ret < 0)
                goto out;
        BUG_ON(ret);
        leaf = path->nodes[0];
        item = btrfs_item_ptr(leaf, path->slots[0],
                              struct btrfs_file_extent_item);
        btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
        btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
        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;
}

int btrfs_insert_inline_extent(struct btrfs_trans_handle *trans,
                               struct btrfs_root *root, u64 objectid,
                               u64 offset, char *buffer, size_t size)
{
        struct btrfs_key key;
        struct btrfs_path *path;
        struct extent_buffer *leaf;
        unsigned long ptr;
        struct btrfs_file_extent_item *ei;
        u32 datasize;
        int err = 0;
        int ret;

        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;

        key.objectid = objectid;
        key.offset = offset;
        btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);

        datasize = btrfs_file_extent_calc_inline_size(size);
        ret = btrfs_insert_empty_item(trans, root, path, &key, datasize);
        if (ret) {
                err = ret;
                goto fail;
        }

        leaf = path->nodes[0];
        ei = btrfs_item_ptr(leaf, path->slots[0],
                            struct btrfs_file_extent_item);
        btrfs_set_file_extent_generation(leaf, ei, trans->transid);
        btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
        btrfs_set_file_extent_ram_bytes(leaf, ei, size);
        btrfs_set_file_extent_compression(leaf, ei, 0);
        btrfs_set_file_extent_encryption(leaf, ei, 0);
        btrfs_set_file_extent_other_encoding(leaf, ei, 0);

        ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
        write_extent_buffer(leaf, buffer, ptr, size);
        btrfs_mark_buffer_dirty(leaf);
fail:
        btrfs_free_path(path);
        return err;
}

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)
{
        int ret;
        struct btrfs_key file_key;
        struct btrfs_key found_key;
        struct btrfs_csum_item *item;
        struct extent_buffer *leaf;
        u64 csum_offset = 0;
        u16 csum_size =
                btrfs_super_csum_size(root->fs_info->super_copy);
        int csums_in_item;

        file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
        file_key.offset = bytenr;
        btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
        ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
        if (ret < 0)
                goto fail;
        leaf = path->nodes[0];
        if (ret > 0) {
                ret = 1;
                if (path->slots[0] == 0)
                        goto fail;
                path->slots[0]--;
                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
                if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY)
                        goto fail;

                csum_offset = (bytenr - found_key.offset) / root->sectorsize;
                csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
                csums_in_item /= csum_size;

                if (csum_offset >= csums_in_item) {
                        ret = -EFBIG;
                        goto fail;
                }
        }
        item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
        item = (struct btrfs_csum_item *)((unsigned char *)item +
                                          csum_offset * csum_size);
        return item;
fail:
        if (ret > 0)
                ret = -ENOENT;
        return ERR_PTR(ret);
}

int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root, u64 alloc_end,
                          u64 bytenr, char *data, size_t len)
{
        int ret = 0;
        struct btrfs_key file_key;
        struct btrfs_key found_key;
        u64 next_offset = (u64)-1;
        int found_next = 0;
        struct btrfs_path *path;
        struct btrfs_csum_item *item;
        struct extent_buffer *leaf = NULL;
        u64 csum_offset;
        u32 csum_result = ~(u32)0;
        u32 nritems;
        u32 ins_size;
        u16 csum_size =
                btrfs_super_csum_size(root->fs_info->super_copy);

        path = btrfs_alloc_path();
        BUG_ON(!path);

        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)) {
                leaf = path->nodes[0];
                ret = 0;
                goto found;
        }
        ret = PTR_ERR(item);
        if (ret == -EFBIG) {
                u32 item_size;
                /* we found one, but it isn't big enough yet */
                leaf = path->nodes[0];
                item_size = btrfs_item_size_nr(leaf, path->slots[0]);
                if ((item_size / csum_size) >= MAX_CSUM_ITEMS(root, csum_size)) {
                        /* already at max size, make a new one */
                        goto insert;
                }
        } else {
                int slot = path->slots[0] + 1;
                /* we didn't find a csum item, insert one */
                nritems = btrfs_header_nritems(path->nodes[0]);
                if (path->slots[0] >= nritems - 1) {
                        ret = btrfs_next_leaf(root, path);
                        if (ret == 1)
                                found_next = 1;
                        if (ret != 0)
                                goto insert;
                        slot = 0;
                }
                btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
                if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
                    found_key.type != BTRFS_EXTENT_CSUM_KEY) {
                        found_next = 1;
                        goto insert;
                }
                next_offset = found_key.offset;
                found_next = 1;
                goto insert;
        }

        /*
         * at this point, we know the tree has an item, but it isn't big
         * enough yet to put our csum in.  Grow it
         */
        btrfs_release_path(path);
        ret = btrfs_search_slot(trans, root, &file_key, path,
                                csum_size, 1);
        if (ret < 0)
                goto fail;
        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 = (file_key.offset - found_key.offset) / root->sectorsize;
        if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
            found_key.type != BTRFS_EXTENT_CSUM_KEY ||
            csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
                goto insert;
        }
        if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
            csum_size) {
                u32 diff = (csum_offset + 1) * csum_size;
                diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
                if (diff != csum_size)
                        goto insert;
                ret = btrfs_extend_item(trans, root, path, diff);
                BUG_ON(ret);
                goto csum;
        }

insert:
        btrfs_release_path(path);
        csum_offset = 0;
        if (found_next) {
                u64 tmp = min(alloc_end, next_offset);
                tmp -= file_key.offset;
                tmp /= root->sectorsize;
                tmp = max((u64)1, tmp);
                tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
                ins_size = csum_size * tmp;
        } else {
                ins_size = csum_size;
        }
        ret = btrfs_insert_empty_item(trans, root, path, &file_key,
                                      ins_size);
        if (ret < 0)
                goto fail;
        if (ret != 0) {
                WARN_ON(1);
                goto fail;
        }
csum:
        leaf = path->nodes[0];
        item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
        ret = 0;
        item = (struct btrfs_csum_item *)((unsigned char *)item +
                                          csum_offset * csum_size);
found:
        csum_result = btrfs_csum_data(root, data, csum_result, len);
        btrfs_csum_final(csum_result, (char *)&csum_result);
        if (csum_result == 0) {
                printk("csum result is 0 for block %llu\n",
                       (unsigned long long)bytenr);
        }

        write_extent_buffer(leaf, &csum_result, (unsigned long)item,
                            csum_size);
        btrfs_mark_buffer_dirty(path->nodes[0]);
fail:
        btrfs_free_path(path);
        return ret;
}

/*
 * helper function for csum removal, this expects the
 * key to describe the csum pointed to by the path, and it expects
 * the csum to overlap the range [bytenr, len]
 *
 * The csum should not be entirely contained in the range and the
 * range should not be entirely contained in the csum.
 *
 * This calls btrfs_truncate_item with the correct args based on the
 * overlap, and fixes up the key as required.
 */
static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
                                      struct btrfs_root *root,
                                      struct btrfs_path *path,
                                      struct btrfs_key *key,
                                      u64 bytenr, u64 len)
{
        struct extent_buffer *leaf;
        u16 csum_size =
                btrfs_super_csum_size(root->fs_info->super_copy);
        u64 csum_end;
        u64 end_byte = bytenr + len;
        u32 blocksize = root->sectorsize;
        int ret;

        leaf = path->nodes[0];
        csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
        csum_end *= root->sectorsize;
        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;
                new_size *= csum_size;
                ret = btrfs_truncate_item(trans, root, path, new_size, 1);
                BUG_ON(ret);
        } else if (key->offset >= bytenr && csum_end > end_byte &&
                   end_byte > key->offset) {
                /*
                 *         [ bytenr - len ]
                 *                 [ ]
                 *                 [csum     ]
                 * we need to truncate from the beginning of the csum
                 */
                u32 new_size = (csum_end - end_byte) / blocksize;
                new_size *= csum_size;

                ret = btrfs_truncate_item(trans, root, path, new_size, 0);
                BUG_ON(ret);

                key->offset = end_byte;
                ret = btrfs_set_item_key_safe(root, path, key);
                BUG_ON(ret);
        } else {
                BUG();
        }
        return 0;
}

/*
 * deletes the csum items from the csum tree for a given
 * range of bytes.
 */
int btrfs_del_csums(struct btrfs_trans_handle *trans,
                    struct btrfs_root *root, u64 bytenr, u64 len)
{
        struct btrfs_path *path;
        struct btrfs_key key;
        u64 end_byte = bytenr + len;
        u64 csum_end;
        struct extent_buffer *leaf;
        int ret;
        u16 csum_size =
                btrfs_super_csum_size(root->fs_info->super_copy);
        int blocksize = root->sectorsize;

        root = root->fs_info->csum_root;

        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)
                                goto out;
                        path->slots[0]--;
                }
                leaf = path->nodes[0];
                btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);

                if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
                    key.type != BTRFS_EXTENT_CSUM_KEY) {
                        break;
                }

                if (key.offset >= end_byte)
                        break;

                csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
                csum_end *= blocksize;
                csum_end += key.offset;

                /* this csum ends before we start, we're done */
                if (csum_end <= bytenr)
                        break;

                /* delete the entire item, it is inside our range */
                if (key.offset >= bytenr && csum_end <= end_byte) {
                        ret = btrfs_del_item(trans, root, path);
                        BUG_ON(ret);
                } 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;
                        offset *= csum_size;

                        shift_len = (len / blocksize) * csum_size;

                        item_offset = btrfs_item_ptr_offset(leaf,
                                                            path->slots[0]);

                        memset_extent_buffer(leaf, 0, item_offset + offset,
                                             shift_len);
                        key.offset = bytenr;

                        /*
                         * btrfs_split_item returns -EAGAIN when the
                         * item changed size or key
                         */
                        ret = btrfs_split_item(trans, root, path, &key, offset);
                        BUG_ON(ret && ret != -EAGAIN);

                        key.offset = end_byte - 1;
                } else {
                        ret = truncate_one_csum(trans, root, path,
                                                &key, bytenr, len);
                        BUG_ON(ret);
                }
                btrfs_release_path(path);
        }
out:
        btrfs_free_path(path);
        return 0;
}