/* fsys_btrfs.c - an implementation for the Btrfs filesystem * * Copyright 2009 Red Hat, Inc. 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 as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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, see . */ #ifdef FSYS_BTRFS #include "shared.h" #include "filesys.h" #include "btrfs.h" #define BTRFS_VERBOSE 0 /* Cache layouts */ #define LOOKUP_CACHE_BUF_SIZE (4096) #define LOOKUP_CACHE_SIZE (LOOKUP_CACHE_BUF_SIZE * LAST_LOOKUP_POOL) #define BTRFS_FS_INFO \ ((struct btrfs_fs_info *)((unsigned long)FSYS_BUF + \ LOOKUP_CACHE_SIZE)) #define BTRFS_CACHE_SIZE (sizeof(struct btrfs_fs_info) + \ LOOKUP_CACHE_SIZE) #define BTRFS_FILE_INFO (&BTRFS_FS_INFO->file_info) #define BTRFS_TREE_ROOT (&BTRFS_FS_INFO->tree_root) #define BTRFS_CHUNK_ROOT (&BTRFS_FS_INFO->chunk_root) #define BTRFS_FS_ROOT (&BTRFS_FS_INFO->fs_root) #define BTRFS_SUPER (&BTRFS_FS_INFO->super_copy) #define LOOKUP_CACHE_BUF(id) ((char *)((unsigned long)FSYS_BUF + \ id * LOOKUP_CACHE_BUF_SIZE)) #define noop do {; } while (0) #if BTRFS_VERBOSE #define btrfs_msg(format, ...) printf(format , ## __VA_ARGS__) #else #define btrfs_msg(format, args...) noop #endif /* compile-time check to make sure we don't overlap filesystem buffer */ static inline void check_btrfs_cache_size(void) { cassert(BTRFS_CACHE_SIZE <= FSYS_BUFLEN); } static inline u64 btrfs_sb_offset(int mirror) { u64 start = 16 * 1024; if (mirror) return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror); return BTRFS_SUPER_INFO_OFFSET; } static inline char *grab_lookup_cache(lookup_pool_id lpid) { char *buf = LOOKUP_CACHE_BUF(lpid); memset(buf, 0, LOOKUP_CACHE_BUF_SIZE); return buf; } static inline struct btrfs_path *btrfs_grab_path(lookup_pool_id lpid) { return &BTRFS_FS_INFO->paths[lpid]; } static inline void btrfs_update_file_info(struct btrfs_path *path) { btrfs_item_key_to_cpu(&path->nodes[0], BTRFS_FILE_INFO, path->slots[0]); } static inline void btrfs_set_root_dir_key(struct btrfs_key *key) { key->objectid = BTRFS_FIRST_FREE_OBJECTID; btrfs_set_key_type(key, BTRFS_INODE_ITEM_KEY); key->offset = 0; } static inline void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src) { char *data = dst->data; memcpy(dst, src, sizeof(*dst)); memcpy(data, src->data, 4096); dst->data = data; } static inline void move_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src) { memcpy(dst, src, sizeof(*dst)); } static inline void init_btrfs_root (struct btrfs_root *root) { root->node.data = root->data; } static inline void init_btrfs_path(lookup_pool_id lpid) { struct btrfs_path *path; path = btrfs_grab_path(lpid); path->lpid = lpid; } static inline void init_btrfs_info(void) { int i; struct btrfs_fs_info *fs = BTRFS_FS_INFO; memset(fs, 0, sizeof (*fs)); for(i = 0; i < LAST_LOOKUP_POOL; i++) init_btrfs_path(i); init_btrfs_root(&fs->tree_root); init_btrfs_root(&fs->chunk_root); init_btrfs_root(&fs->fs_root); } static void setup_root(struct btrfs_root *root, u32 nodesize, u32 leafsize, u32 sectorsize, u32 stripesize, u64 objectid) { root->fs_info = BTRFS_FS_INFO; root->nodesize = nodesize; root->leafsize = leafsize; root->sectorsize = sectorsize; root->stripesize = stripesize; root->objectid = objectid; } /* * Pick up the latest root of a * tree with specified @objectid */ static int btrfs_find_last_root(struct btrfs_root *tree_root, u64 objectid, struct btrfs_root_item *item, struct btrfs_key *key, lookup_pool_id lpid) { int ret; int slot; struct btrfs_key search_key; struct btrfs_key found_key; struct btrfs_path *path; search_key.objectid = objectid; search_key.type = BTRFS_ROOT_ITEM_KEY; search_key.offset = (u64)-1; path = btrfs_grab_path(lpid); ret = aux_tree_lookup(tree_root, &search_key, path); if (ret < 0) return 1; slot = path->slots[0]; WARN_ON(slot == 0); slot -= 1; btrfs_item_key_to_cpu(&path->nodes[0], &found_key, slot); if (found_key.objectid != objectid) return 1; read_extent_buffer(&path->nodes[0], item, btrfs_item_ptr_offset(&path->nodes[0], slot), sizeof(*item)); memcpy(key, &found_key, sizeof(found_key)); return 0; } static int find_setup_root(struct btrfs_root *tree_root, u32 nodesize, u32 leafsize, u32 sectorsize, u32 stripesize, u64 objectid, struct btrfs_root *dest_root, u64 bytenr, u32 blocksize, u64 generation, lookup_pool_id lpid) { int ret; struct extent_buffer eb; setup_root(dest_root, nodesize, leafsize, sectorsize, stripesize, objectid); if (tree_root) { /* * pick up the latest version * of the root we want to set up */ ret = btrfs_find_last_root(tree_root, objectid, &dest_root->root_item, &dest_root->root_key, lpid); if (ret) return ret; bytenr = btrfs_root_bytenr(&dest_root->root_item); blocksize = btrfs_level_size(dest_root, btrfs_root_level(&dest_root->root_item)); generation = btrfs_root_generation(&tree_root->root_item); } ret = read_tree_block(dest_root, &eb, bytenr, blocksize, generation, lpid); if (!ret) return 1; copy_extent_buffer(&dest_root->node, &eb); return 0; } static inline int btrfs_strncmp(const char *cs, const char *ct, int count) { signed char __res = 0; while (count) { if ((__res = *cs - *ct++) != 0 || !*cs++) break; count--; } return __res; } static int btrfs_check_super_block(struct btrfs_super_block *sb) { if (sb->num_devices != BTRFS_DEFAULT_NUM_DEVICES) { btrfs_msg("Btrfs multi-device configuration unsupported\n"); goto error; } if (sb->nodesize != BTRFS_DEFAULT_NODE_SIZE) { btrfs_msg("Btrfs node size (%d) != %d unsupported\n", sb->nodesize, BTRFS_DEFAULT_NODE_SIZE); goto error; } if (sb->leafsize != BTRFS_DEFAULT_LEAF_SIZE) { btrfs_msg("Btrfs leaf size (%d) != %d unsupported\n", sb->leafsize, BTRFS_DEFAULT_LEAF_SIZE); goto error; } return 1; error: errnum = ERR_FSYS_MOUNT; return 0; } int btrfs_mount(void) { int i; int ret; u64 transid = 0; u64 bytenr; struct btrfs_fs_info *fs = BTRFS_FS_INFO; struct btrfs_super_block *sb_tmp; /* current */ struct btrfs_super_block *sb; /* latest */ struct btrfs_root *tree_root = &fs->tree_root; struct btrfs_root *chunk_root = &fs->chunk_root; struct btrfs_root *fs_root = &fs->fs_root; check_btrfs_cache_size(); init_btrfs_info(); sb_tmp = &fs->super_temp; sb = &fs->super_copy; /* pick up the latest version of superblock */ for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) { bytenr = btrfs_sb_offset(i); ret = devread(bytenr >> SECTOR_BITS, 0, sizeof(*sb_tmp), (char *)sb_tmp); if (!ret) continue; if (btrfs_super_bytenr(sb_tmp) != bytenr || btrfs_strncmp((char *)(&sb_tmp->magic), BTRFS_MAGIC, sizeof(sb_tmp->magic))) continue; if (btrfs_super_generation(sb_tmp) > transid) { memcpy(sb, sb_tmp, sizeof(*sb_tmp)); transid = btrfs_super_generation(sb); } } /* there might be errors when reading super mirrors */ if (errnum == ERR_OUTSIDE_PART) errnum = ERR_NONE; if (transid <= 0) { btrfs_msg("No valid Btrfs superblock found\n"); return 0; } if (!btrfs_check_super_block(sb)) return 0; /* setup chunk root */ ret = find_setup_root(NULL, btrfs_super_nodesize(sb), btrfs_super_leafsize(sb), btrfs_super_sectorsize(sb), btrfs_super_stripesize(sb), BTRFS_CHUNK_TREE_OBJECTID, chunk_root, btrfs_super_chunk_root(sb), btrfs_chunk_root_level_size(sb), btrfs_super_chunk_root_generation(sb), FIRST_EXTERNAL_LOOKUP_POOL); if (ret) return 0; /* setup tree root */ ret = find_setup_root(NULL, btrfs_super_nodesize(sb), btrfs_super_leafsize(sb), btrfs_super_sectorsize(sb), btrfs_super_stripesize(sb), BTRFS_ROOT_TREE_OBJECTID, tree_root, btrfs_super_root(sb), btrfs_root_level_size(sb), btrfs_super_generation(sb), FIRST_EXTERNAL_LOOKUP_POOL); if (ret) return 0; /* setup fs_root */ ret = find_setup_root(tree_root, btrfs_super_nodesize(sb), btrfs_super_leafsize(sb), btrfs_super_sectorsize(sb), btrfs_super_stripesize(sb), BTRFS_FS_TREE_OBJECTID, fs_root, 0, 0, 0, FIRST_EXTERNAL_LOOKUP_POOL); return !ret; } /* * Check, whether @chunk is the map for a * block with @logical block number. * If yes, then fill the @map. * Return 1 on affirmative result, * otherwise return 0. */ int check_read_chunk(struct btrfs_key *key, struct extent_buffer *leaf, struct btrfs_chunk *chunk, struct map_lookup *map, u64 logical) { int i; u64 chunk_start; u64 chunk_size; int num_stripes; chunk_start = key->offset; chunk_size = btrfs_chunk_length(leaf, chunk); if (logical + 1 > chunk_start + chunk_size || logical < chunk_start) /* not a fit */ return 0; num_stripes = btrfs_chunk_num_stripes(leaf, chunk); map->ce.start = chunk_start; map->ce.size = chunk_size; map->num_stripes = num_stripes; map->io_width = btrfs_chunk_io_width(leaf, chunk); map->io_align = btrfs_chunk_io_align(leaf, chunk); map->sector_size = btrfs_chunk_sector_size(leaf, chunk); map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk); map->type = btrfs_chunk_type(leaf, chunk); map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk); for (i = 0; i < num_stripes; i++) { map->stripes[i].physical = btrfs_stripe_offset_nr(leaf, chunk, i); } return 1; } static void init_extent_buffer(struct extent_buffer *eb, u64 logical, u32 blocksize, u64 physical, lookup_pool_id lpid) { eb->start = logical; eb->len = blocksize; eb->refs = 2; eb->flags = 0; eb->dev_bytenr = physical; eb->data = grab_lookup_cache(lpid); } /* * Search for a map by logical offset in sys array. * Return -1 on errors; * Return 1 if the map is found, * Return 0 if the map is not found. */ int sys_array_lookup(struct map_lookup *map, u64 logical) { struct extent_buffer sb; struct btrfs_disk_key *disk_key; struct btrfs_chunk *chunk; struct btrfs_key key; u32 num_stripes; u32 array_size; u32 len = 0; u8 *ptr; unsigned long sb_ptr; u32 cur; int ret; int i = 0; sb.data = (char *)BTRFS_SUPER; array_size = btrfs_super_sys_array_size(BTRFS_SUPER); ptr = BTRFS_SUPER->sys_chunk_array; sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array); cur = 0; while (cur < array_size) { disk_key = (struct btrfs_disk_key *)ptr; btrfs_disk_key_to_cpu(&key, disk_key); len = sizeof(*disk_key); ptr += len; sb_ptr += len; cur += len; if (key.type == BTRFS_CHUNK_ITEM_KEY) { chunk = (struct btrfs_chunk *)sb_ptr; ret = check_read_chunk(&key, &sb, chunk, map, logical); if (ret) /* map is found */ return ret; num_stripes = btrfs_chunk_num_stripes(&sb, chunk); len = btrfs_chunk_item_size(num_stripes); } else { errnum = ERR_FSYS_CORRUPT; return -1; } ptr += len; sb_ptr += len; cur += len; i++; } return 0; } /* * Search for a map by logical offset in the chunk tree. * Return 1 if map is found, otherwise return 0. */ static int chunk_tree_lookup(struct map_lookup *map, u64 logical) { int ret; int slot; struct extent_buffer *leaf; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_chunk *chunk; struct btrfs_path *path; path = btrfs_grab_path(INTERNAL_LOOKUP_POOL); key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID; key.offset = logical; key.type = BTRFS_CHUNK_ITEM_KEY; ret = aux_tree_lookup(BTRFS_CHUNK_ROOT, &key, path); if (ret < 0) return 0; leaf = &path->nodes[0]; slot = path->slots[0]; if (ret == 1) { WARN_ON(slot == 0); slot -= 1; } btrfs_item_key_to_cpu(leaf, &found_key, slot); if (found_key.type != BTRFS_CHUNK_ITEM_KEY) return 0; chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk); return check_read_chunk(&found_key, leaf, chunk, map, logical); } /* * Btrfs logical/physical block mapper. * Look for an appropriate map-extent and * perform a translation. Return 1 on errors. */ int __btrfs_map_block(u64 logical, u64 *length, struct btrfs_multi_bio *multi, int mirror_num) { struct map_lookup map; u64 offset; u64 stripe_offset; u64 stripe_nr; struct cache_extent *ce; int stripe_index; int i; int ret; memset(&map, 0, sizeof(map)); ret = sys_array_lookup(&map, logical); if (ret == -1) { errnum = ERR_FSYS_CORRUPT; return 1; } if (ret == 0) { ret = chunk_tree_lookup(&map, logical); if (!ret) { /* something should be found! */ errnum = ERR_FSYS_CORRUPT; return 1; } } /* do translation */ ce = &map.ce; offset = logical - ce->start; stripe_nr = offset / map.stripe_len; stripe_offset = stripe_nr * map.stripe_len; WARN_ON(offset < stripe_offset); stripe_offset = offset - stripe_offset; if (map.type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10 | BTRFS_BLOCK_GROUP_DUP)) { *length = min_t(u64, ce->size - offset, map.stripe_len - stripe_offset); } else { *length = ce->size - offset; } multi->num_stripes = 1; stripe_index = 0; if (map.type & BTRFS_BLOCK_GROUP_RAID1) { if (mirror_num) stripe_index = mirror_num - 1; else stripe_index = stripe_nr % map.num_stripes; } else if (map.type & BTRFS_BLOCK_GROUP_RAID10) { int factor = map.num_stripes / map.sub_stripes; stripe_index = stripe_nr % factor; stripe_index *= map.sub_stripes; if (mirror_num) stripe_index += mirror_num - 1; else stripe_index = stripe_nr % map.sub_stripes; stripe_nr = stripe_nr / factor; } else if (map.type & BTRFS_BLOCK_GROUP_DUP) { if (mirror_num) stripe_index = mirror_num - 1; } else { stripe_index = stripe_nr % map.num_stripes; stripe_nr = stripe_nr / map.num_stripes; } WARN_ON(stripe_index >= map.num_stripes); for (i = 0; i < multi->num_stripes; i++) { multi->stripes[i].physical = map.stripes[stripe_index].physical + stripe_offset + stripe_nr * map.stripe_len; stripe_index++; } return 0; } static u64 btrfs_map_block(u64 logical) { int ret; u64 length; struct btrfs_multi_bio multi; ret = __btrfs_map_block(logical, &length, &multi, 0); if (ret) { errnum = ERR_FSYS_CORRUPT; return 0; } return multi.stripes[0].physical; } static int read_extent_from_disk(struct extent_buffer *eb) { WARN_ON(eb->dev_bytenr % SECTOR_BITS); return devread(eb->dev_bytenr >> SECTOR_BITS, 0, eb->len, eb->data); } static int verify_parent_transid(struct extent_buffer *eb, u64 parent_transid) { return parent_transid && (btrfs_header_generation(eb) != parent_transid); } static int btrfs_num_copies(u64 logical, u64 len) { return 1; } static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf) { return 0; } static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf, int verify) { return 0; } /* * Read a block of logical number @bytenr * from disk to buffer @eb. * Return 1 on success. */ int read_tree_block(struct btrfs_root *root, struct extent_buffer *eb, u64 bytenr, /* logical */ u32 blocksize, u64 parent_transid, lookup_pool_id lpid) { int ret; int dev_nr; u64 length; struct btrfs_multi_bio multi; int mirror_num = 0; int num_copies; dev_nr = 0; length = blocksize; while (1) { ret = __btrfs_map_block(bytenr, &length, &multi, mirror_num); if (ret) { errnum = ERR_FSYS_CORRUPT; return 0; } init_extent_buffer(eb, bytenr, blocksize, multi.stripes[0].physical, lpid); ret = read_extent_from_disk(eb); if (ret && check_tree_block(root, eb) == 0 && csum_tree_block(root, eb, 1) == 0 && verify_parent_transid(eb, parent_transid) == 0) return 1; num_copies = btrfs_num_copies(eb->start, eb->len); if (num_copies == 1) break; mirror_num++; if (mirror_num > num_copies) break; } return 0; } /* * Read a child pointed by @slot node pointer * of @parent. Put the result to @parent. * Return 1 on success. */ static int parent2child(struct btrfs_root *root, struct extent_buffer *parent, int slot, lookup_pool_id lpid) { int level; WARN_ON(slot < 0); WARN_ON(slot >= btrfs_header_nritems(parent)); level = btrfs_header_level(parent); WARN_ON(level <= 0); return read_tree_block(root, parent, btrfs_node_blockptr(parent, slot), btrfs_level_size(root, level - 1), btrfs_node_ptr_generation(parent, slot), lpid); } static int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2) { struct btrfs_key k1; btrfs_disk_key_to_cpu(&k1, disk); if (k1.objectid > k2->objectid) return 1; if (k1.objectid < k2->objectid) return -1; if (k1.type > k2->type) return 1; if (k1.type < k2->type) return -1; if (k1.offset > k2->offset) return 1; if (k1.offset < k2->offset) return -1; return 0; } static int bin_search(struct extent_buffer *eb, unsigned long p, int item_size, struct btrfs_key *key, int max, int *slot) { int low = 0; int high = max; int mid; int ret; unsigned long offset; struct btrfs_disk_key *tmp; while(low < high) { mid = (low + high) / 2; offset = p + mid * item_size; tmp = (struct btrfs_disk_key *)(eb->data + offset); ret = btrfs_comp_keys(tmp, key); if (ret < 0) low = mid + 1; else if (ret > 0) high = mid; else { *slot = mid; return 0; } } *slot = low; return 1; } /* look for a key in a node */ static int node_lookup(struct extent_buffer *eb, struct btrfs_key *key, int *slot) { if (btrfs_header_level(eb) == 0) { return bin_search(eb, offsetof(struct btrfs_leaf, items), sizeof(struct btrfs_item), key, btrfs_header_nritems(eb), slot); } else { return bin_search(eb, offsetof(struct btrfs_node, ptrs), sizeof(struct btrfs_key_ptr), key, btrfs_header_nritems(eb), slot); } return -1; } static inline int check_node(struct extent_buffer *buf, int slot) { return 0; } /* * Look for an item by key in read-only tree. * Return 0, if key was found. Return -1 on io errors. * * Preconditions: btrfs_mount already executed. * Postconditions: if returned value is non-negative, * then path[0] represents the found position in the * tree. All components of the @path from leaf to root * are valid except their data buffers (only path[0] * has valid attached data buffer). */ int aux_tree_lookup(struct btrfs_root *root, struct btrfs_key *key, struct btrfs_path *path) { int ret; int slot = 0; int level; struct extent_buffer node; init_extent_buffer(&node, 0, 0, 0, path->lpid); copy_extent_buffer(&node, &root->node); do { level = btrfs_header_level(&node); ret = check_node(&node, slot); if (ret) return -1; move_extent_buffer(&path->nodes[level], &node); ret = node_lookup(&node, key, &slot); if (ret < 0) return ret; if (level) { /* * non-leaf, * jump to the next level */ if (ret && slot > 0) slot -= 1; ret = parent2child(root, &node, slot, path->lpid); if (ret == 0) return -1; } path->slots[level] = slot; } while (level); return ret; } static int readup_buffer(struct extent_buffer *buf, lookup_pool_id lpid) { buf->data = grab_lookup_cache(lpid); return read_extent_from_disk(buf); } /* * Find the next leaf in accordance with tree order; * walk up the tree as far as required to find it. * Returns 0 if something was found, or 1 if there * are no greater leaves. Returns < 0 on io errors. * * Preconditions: all @path components from leaf to * root have valid meta-data fields. path[0] has a * valid attached data buffer with initial leaf. * Postcondition: the same as above, but path[0] has * an attached data buffer with the next leaf. */ static int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) { int res; int slot; int level = 1; struct extent_buffer *buf; while(level < BTRFS_MAX_LEVEL) { buf = &path->nodes[level]; slot = path->slots[level] + 1; /* * lift data on this level */ res = readup_buffer(buf, path->lpid); if (!res) break; if (slot >= btrfs_header_nritems(buf)) { /* alas, go to parent (if any) */ level++; res = 1; continue; } break; } if (!res) return 1; /* * At this level slot points to * the subtree we are interested in. */ path->slots[level] = slot; while(level) { struct extent_buffer tmp; move_extent_buffer(&tmp, &path->nodes[level]); res = parent2child(root, &tmp, slot, path->lpid); if (res == 0) return -1; level --; slot = 0; move_extent_buffer(&path->nodes[level], &tmp); path->slots[level] = slot; } return 0; } /* Preconditions: path is valid, data buffer * is attached to leaf node. * Postcondition: path is updated to point to * the next position with respect to the tree * order. * * Return -1 on io errors. * Return 0, if next item was found. * Return 1, if next item wasn't found (no more items). */ static int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *path) { WARN_ON(path->slots[0] >= btrfs_header_nritems(&path->nodes[0])); path->slots[0] += 1; if (path->slots[0] < btrfs_header_nritems(&path->nodes[0])) return 0; if (coord_is_root(root, path)) /* no more items */ return 1; return btrfs_next_leaf(root, path); } /* * check if we can reuse results of previous * search for read operation */ static int path_is_valid(struct btrfs_path *path, struct btrfs_key *key) { btrfs_item_key_to_cpu(&path->nodes[0], key, path->slots[0]); return (key->objectid == BTRFS_FILE_INFO->objectid) && (btrfs_key_type(key) == BTRFS_EXTENT_DATA_KEY); } /* ->read_func() */ int btrfs_read(char *buf, int len) { int ret; struct btrfs_root *fs_root; struct btrfs_path *path; struct btrfs_key *info_key; struct btrfs_key path_key; u64 off; u64 bytes; unsigned int to_read; char *pos = buf; fs_root = BTRFS_FS_ROOT; info_key = BTRFS_FILE_INFO; path = btrfs_grab_path(FIRST_EXTERNAL_LOOKUP_POOL); if (!path_is_valid(path, &path_key)) { btrfs_set_key_type(info_key, BTRFS_EXTENT_DATA_KEY); info_key->offset = filepos; ret = aux_tree_lookup(fs_root, info_key, path); if (ret < 0) errnum = ERR_FSYS_CORRUPT; } while (!errnum) { struct btrfs_item *item; struct btrfs_file_extent_item *fi; unsigned int from; if (!path_is_valid(path, &path_key)) break; item = btrfs_item_nr(&path->nodes[0], path->slots[0]); fi = btrfs_item_ptr(&path->nodes[0], path->slots[0], struct btrfs_file_extent_item); if (btrfs_file_extent_compression(&path->nodes[0], fi)) { btrfs_msg("Btrfs transparent compression unsupported\n"); errnum = ERR_BAD_FILETYPE; goto exit; } off = filepos - path_key.offset; switch (btrfs_file_extent_type(&path->nodes[0], fi)) { case BTRFS_FILE_EXTENT_INLINE: bytes = btrfs_file_extent_inline_item_len(&path-> nodes[0], item); to_read = bytes - off; if (to_read > len) to_read = len; from = off + btrfs_file_extent_inline_start(fi); if (disk_read_hook != NULL) { disk_read_func = disk_read_hook; ret = devread(path->nodes[0].dev_bytenr >> SECTOR_BITS, from, to_read, pos); disk_read_func = NULL; } else { memcpy(pos, path->nodes[0].data + from, to_read); } break; case BTRFS_FILE_EXTENT_REG: bytes = btrfs_file_extent_num_bytes(&path->nodes[0], fi); to_read = bytes - off; if (to_read > len) to_read = len; from = off + btrfs_file_extent_disk_bytenr(&path->nodes[0], fi); disk_read_func = disk_read_hook; ret = devread(btrfs_map_block(from) >> SECTOR_BITS, from & ((u64)SECTOR_SIZE - 1), to_read, pos); disk_read_func = NULL; if (!ret) goto exit; break; case BTRFS_FILE_EXTENT_PREALLOC: btrfs_msg("Btrfs preallocated extents unsupported\n"); errnum = ERR_BAD_FILETYPE; goto exit; default: errnum = ERR_FSYS_CORRUPT; goto exit; } len -= to_read; pos += to_read; filepos += to_read; if (len == 0) break; /* not everything was read */ ret = btrfs_next_item(fs_root, path); if (ret) { /* something should be found */ errnum = ERR_FSYS_CORRUPT; break; } } exit: return errnum ? 0 : pos - buf; } static int btrfs_follow_link(struct btrfs_root *root, struct btrfs_path *path, char **dirname, char *linkbuf, int *link_count, struct btrfs_inode_item *sd) { int ret; int len; char *name = *dirname; if (++(*link_count) > MAX_LINK_COUNT) { errnum = ERR_SYMLINK_LOOP; return 0; } /* calculate remaining name size */ filemax = btrfs_inode_size(&path->nodes[0], sd); for (len = 0; name[len] && isspace(name[len]); len ++); if (filemax + len > PATH_MAX - 1) { errnum = ERR_FILELENGTH; return 0; } grub_memmove(linkbuf + filemax, name, len + 1); btrfs_update_file_info(path); filepos = 0; /* extract symlink content */ while (1) { u64 oid = BTRFS_FILE_INFO->objectid; ret = btrfs_next_item(root, path); if (ret) break; btrfs_update_file_info(path); if (oid != BTRFS_FILE_INFO->objectid) break; if (btrfs_key_type(BTRFS_FILE_INFO) == BTRFS_EXTENT_DATA_KEY) goto found; } /* no target was found */ errnum = ERR_FSYS_CORRUPT; return 0; found: /* fill the rest of linkbuf with the content */ ret = btrfs_read(linkbuf, filemax); if (ret != filemax) { errnum = ERR_FSYS_CORRUPT; return 0; } return 1; } static int update_fs_root(struct btrfs_root *fs_root, struct btrfs_key *location) { int ret; struct btrfs_root *tree_root; if (location->offset != (u64)-1) return 0; tree_root = &fs_root->fs_info->tree_root; ret = find_setup_root(tree_root, tree_root->nodesize, tree_root->leafsize, tree_root->sectorsize, tree_root->stripesize, location->objectid, fs_root, 0, 0, 0, SECOND_EXTERNAL_LOOKUP_POOL); if (ret) return ret; location->objectid = btrfs_root_dirid(&fs_root->root_item); btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY); location->offset = 0; return 0; } #ifndef STAGE1_5 static inline void update_possibilities(void) { if (print_possibilities > 0) print_possibilities = -print_possibilities; } #endif /* * Look for a directory item by name. * Print possibilities, if needed. * Postconditions: on success @sd_key points * to the key contained in the directory entry. */ static int btrfs_de_index_by_name(struct btrfs_root *root, struct btrfs_path *path, char **dirname, struct btrfs_key *sd_key) { char ch; int ret; char *rest; struct btrfs_dir_item *di; #ifndef STAGE1_5 int do_possibilities = 0; #endif for (; **dirname == '/'; (*dirname)++); for (rest = *dirname; (ch = *rest) && !isspace(ch) && ch != '/'; rest++); *rest = 0; /* for substrung() */ #ifndef STAGE1_5 if (print_possibilities && ch != '/') do_possibilities = 1; #endif /* scan a directory */ while (1) { u32 total; u32 cur = 0; u32 len; struct btrfs_key di_key; struct btrfs_disk_key location; struct btrfs_item *item; /* extract next dir entry */ ret = btrfs_next_item(root, path); if (ret) break; item = btrfs_item_nr(&path->nodes[0], path->slots[0]); btrfs_item_key_to_cpu(&path->nodes[0], &di_key, path->slots[0]); if (di_key.objectid != sd_key->objectid) /* no more entries */ break; di = btrfs_item_ptr(&path->nodes[0], path->slots[0], struct btrfs_dir_item); /* * working around special cases: * btrfs doesn't maintain directory entries * which contain names "." and ".." */ if (!substring(".", *dirname)) { #ifndef STAGE1_5 if (do_possibilities) { update_possibilities(); return 1; } #endif goto found; } if (!substring("..", *dirname)) { if (di_key.type != BTRFS_INODE_REF_KEY) continue; sd_key->objectid = di_key.offset; btrfs_set_key_type(sd_key, BTRFS_INODE_ITEM_KEY); sd_key->offset = 0; #ifndef STAGE1_5 if (do_possibilities) { update_possibilities(); return 1; } #endif goto found; } if (di_key.type != BTRFS_DIR_ITEM_KEY) continue; total = btrfs_item_size(&path->nodes[0], item); /* scan a directory item */ while (cur < total) { char tmp; int result; char *filename; char *end_of_name; int name_len; int data_len; btrfs_dir_item_key(&path->nodes[0], di, &location); name_len = btrfs_dir_name_len(&path->nodes[0], di); data_len = btrfs_dir_data_len(&path->nodes[0], di); WARN_ON(name_len > BTRFS_NAME_LEN); filename = (char *)(path->nodes[0].data + (unsigned long)(di + 1)); end_of_name = filename + name_len; /* * working around not null-terminated * directory names in btrfs: just * a short-term overwrite of the * cache with the following rollback * of the change. */ tmp = *end_of_name; *end_of_name = 0; result = substring(*dirname, filename); *end_of_name = tmp; #ifndef STAGE1_5 if (do_possibilities) { if (result <= 0) { update_possibilities(); *end_of_name = 0; print_a_completion(filename); *end_of_name = tmp; } } else #endif if (result == 0) { btrfs_dir_item_key_to_cpu(&path->nodes[0], di, sd_key); goto found; } len = sizeof(*di) + name_len + data_len; di = (struct btrfs_dir_item *)((char *)di + len); cur += len; } } #ifndef STAGE1_5 if (print_possibilities < 0) return 1; #endif errnum = ERR_FILE_NOT_FOUND; *rest = ch; return 0; found: *rest = ch; *dirname = rest; return 1; } /* * ->dir_func(). * Postcondition: on a non-zero return BTRFS_FS_INFO * contains the latest fs_root of file's subvolume. * BTRFS_FS_INFO points to a subvolume of a file we * were trying to look up. * BTRFS_FILE_INFO contains info of the file we were * trying to look up. */ int btrfs_dir(char *dirname) { int ret; int mode; u64 size; int linkcount = 0; char linkbuf[PATH_MAX]; struct btrfs_path *path; struct btrfs_root *root; struct btrfs_key sd_key; struct btrfs_inode_item *sd; struct btrfs_key parent_sd_key; root = BTRFS_FS_ROOT; path = btrfs_grab_path(FIRST_EXTERNAL_LOOKUP_POOL); btrfs_set_root_dir_key(&sd_key); while (1) { struct extent_buffer *leaf; ret = aux_tree_lookup(root, &sd_key, path); if (ret) return 0; leaf = &path->nodes[0]; sd = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item); mode = btrfs_inode_mode(leaf, sd); size = btrfs_inode_size(leaf, sd); switch (btrfs_get_file_type(mode)) { case BTRFS_SYMLINK_FILE: ret = btrfs_follow_link(root, path, &dirname, linkbuf, &linkcount, sd); if (!ret) return 0; dirname = linkbuf; if (*dirname == '/') /* absolute name */ btrfs_set_root_dir_key(&sd_key); else memcpy(&sd_key, &parent_sd_key, sizeof(sd_key)); continue; case BTRFS_REGULAR_FILE: /* * normally we want to exit here */ if (*dirname && !isspace (*dirname)) { errnum = ERR_BAD_FILETYPE; return 0; } filepos = 0; filemax = btrfs_inode_size(leaf, sd); btrfs_update_file_info(path); return 1; case BTRFS_DIRECTORY_FILE: memcpy(&parent_sd_key, &sd_key, sizeof(sd_key)); ret = btrfs_de_index_by_name(root, path, &dirname, &sd_key); if (!ret) return 0; #ifndef STAGE1_5 if (print_possibilities < 0) return 1; #endif /* * update fs_tree: * subvolume stuff goes here */ ret = update_fs_root(root, &sd_key); if (ret) return 0; continue; case BTRFS_UNKNOWN_FILE: default: btrfs_msg("Btrfs: bad file type\n"); errnum = ERR_BAD_FILETYPE; return 0; } } } #endif /* FSYS_BTRFS */ /* Local variables: c-indentation-style: "K&R" mode-name: "LC" c-basic-offset: 8 tab-width: 8 fill-column: 80 scroll-step: 1 End: */