diff options
Diffstat (limited to 'fs/btrfs/inode-item.c')
| -rw-r--r-- | fs/btrfs/inode-item.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c new file mode 100644 index 000000000..a8956a3c9 --- /dev/null +++ b/fs/btrfs/inode-item.c @@ -0,0 +1,435 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2007 Oracle. All rights reserved. + */ + +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "print-tree.h" + +int btrfs_find_name_in_backref(struct extent_buffer *leaf, int slot, + const char *name, + int name_len, struct btrfs_inode_ref **ref_ret) +{ + struct btrfs_inode_ref *ref; + unsigned long ptr; + unsigned long name_ptr; + u32 item_size; + u32 cur_offset = 0; + int len; + + item_size = btrfs_item_size_nr(leaf, slot); + ptr = btrfs_item_ptr_offset(leaf, slot); + while (cur_offset < item_size) { + ref = (struct btrfs_inode_ref *)(ptr + cur_offset); + len = btrfs_inode_ref_name_len(leaf, ref); + name_ptr = (unsigned long)(ref + 1); + cur_offset += len + sizeof(*ref); + if (len != name_len) + continue; + if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) { + if (ref_ret) + *ref_ret = ref; + return 1; + } + } + return 0; +} + +int btrfs_find_name_in_ext_backref(struct extent_buffer *leaf, int slot, + u64 ref_objectid, + const char *name, int name_len, + struct btrfs_inode_extref **extref_ret) +{ + struct btrfs_inode_extref *extref; + unsigned long ptr; + unsigned long name_ptr; + u32 item_size; + u32 cur_offset = 0; + int ref_name_len; + + item_size = btrfs_item_size_nr(leaf, slot); + ptr = btrfs_item_ptr_offset(leaf, slot); + + /* + * Search all extended backrefs in this item. We're only + * looking through any collisions so most of the time this is + * just going to compare against one buffer. If all is well, + * we'll return success and the inode ref object. + */ + while (cur_offset < item_size) { + extref = (struct btrfs_inode_extref *) (ptr + cur_offset); + name_ptr = (unsigned long)(&extref->name); + ref_name_len = btrfs_inode_extref_name_len(leaf, extref); + + if (ref_name_len == name_len && + btrfs_inode_extref_parent(leaf, extref) == ref_objectid && + (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)) { + if (extref_ret) + *extref_ret = extref; + return 1; + } + + cur_offset += ref_name_len + sizeof(*extref); + } + return 0; +} + +/* Returns NULL if no extref found */ +struct btrfs_inode_extref * +btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + const char *name, int name_len, + u64 inode_objectid, u64 ref_objectid, int ins_len, + int cow) +{ + int ret; + struct btrfs_key key; + struct btrfs_inode_extref *extref; + + key.objectid = inode_objectid; + key.type = BTRFS_INODE_EXTREF_KEY; + key.offset = btrfs_extref_hash(ref_objectid, name, name_len); + + ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow); + if (ret < 0) + return ERR_PTR(ret); + if (ret > 0) + return NULL; + if (!btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0], + ref_objectid, name, name_len, + &extref)) + return NULL; + return extref; +} + +static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + const char *name, int name_len, + u64 inode_objectid, u64 ref_objectid, + u64 *index) +{ + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_inode_extref *extref; + struct extent_buffer *leaf; + int ret; + int del_len = name_len + sizeof(*extref); + unsigned long ptr; + unsigned long item_start; + u32 item_size; + + key.objectid = inode_objectid; + key.type = BTRFS_INODE_EXTREF_KEY; + key.offset = btrfs_extref_hash(ref_objectid, name, name_len); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret > 0) + ret = -ENOENT; + if (ret < 0) + goto out; + + /* + * Sanity check - did we find the right item for this name? + * This should always succeed so error here will make the FS + * readonly. + */ + if (!btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0], + ref_objectid, + name, name_len, &extref)) { + btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL); + ret = -EROFS; + goto out; + } + + leaf = path->nodes[0]; + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + if (index) + *index = btrfs_inode_extref_index(leaf, extref); + + if (del_len == item_size) { + /* + * Common case only one ref in the item, remove the + * whole item. + */ + ret = btrfs_del_item(trans, root, path); + goto out; + } + + ptr = (unsigned long)extref; + item_start = btrfs_item_ptr_offset(leaf, path->slots[0]); + + memmove_extent_buffer(leaf, ptr, ptr + del_len, + item_size - (ptr + del_len - item_start)); + + btrfs_truncate_item(root->fs_info, path, item_size - del_len, 1); + +out: + btrfs_free_path(path); + + return ret; +} + +int btrfs_del_inode_ref(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + const char *name, int name_len, + u64 inode_objectid, u64 ref_objectid, u64 *index) +{ + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_inode_ref *ref; + struct extent_buffer *leaf; + unsigned long ptr; + unsigned long item_start; + u32 item_size; + u32 sub_item_len; + int ret; + int search_ext_refs = 0; + int del_len = name_len + sizeof(*ref); + + key.objectid = inode_objectid; + key.offset = ref_objectid; + key.type = BTRFS_INODE_REF_KEY; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret > 0) { + ret = -ENOENT; + search_ext_refs = 1; + goto out; + } else if (ret < 0) { + goto out; + } + if (!btrfs_find_name_in_backref(path->nodes[0], path->slots[0], + name, name_len, &ref)) { + ret = -ENOENT; + search_ext_refs = 1; + goto out; + } + leaf = path->nodes[0]; + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + + if (index) + *index = btrfs_inode_ref_index(leaf, ref); + + if (del_len == item_size) { + ret = btrfs_del_item(trans, root, path); + goto out; + } + ptr = (unsigned long)ref; + sub_item_len = name_len + sizeof(*ref); + item_start = btrfs_item_ptr_offset(leaf, path->slots[0]); + memmove_extent_buffer(leaf, ptr, ptr + sub_item_len, + item_size - (ptr + sub_item_len - item_start)); + btrfs_truncate_item(root->fs_info, path, item_size - sub_item_len, 1); +out: + btrfs_free_path(path); + + if (search_ext_refs) { + /* + * No refs were found, or we could not find the + * name in our ref array. Find and remove the extended + * inode ref then. + */ + return btrfs_del_inode_extref(trans, root, name, name_len, + inode_objectid, ref_objectid, index); + } + + return ret; +} + +/* + * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree. + * + * The caller must have checked against BTRFS_LINK_MAX already. + */ +static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + const char *name, int name_len, + u64 inode_objectid, u64 ref_objectid, u64 index) +{ + struct btrfs_inode_extref *extref; + int ret; + int ins_len = name_len + sizeof(*extref); + unsigned long ptr; + struct btrfs_path *path; + struct btrfs_key key; + struct extent_buffer *leaf; + struct btrfs_item *item; + + key.objectid = inode_objectid; + key.type = BTRFS_INODE_EXTREF_KEY; + key.offset = btrfs_extref_hash(ref_objectid, name, name_len); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + ret = btrfs_insert_empty_item(trans, root, path, &key, + ins_len); + if (ret == -EEXIST) { + if (btrfs_find_name_in_ext_backref(path->nodes[0], + path->slots[0], + ref_objectid, + name, name_len, NULL)) + goto out; + + btrfs_extend_item(root->fs_info, path, ins_len); + ret = 0; + } + if (ret < 0) + goto out; + + leaf = path->nodes[0]; + item = btrfs_item_nr(path->slots[0]); + ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char); + ptr += btrfs_item_size(leaf, item) - ins_len; + extref = (struct btrfs_inode_extref *)ptr; + + btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len); + btrfs_set_inode_extref_index(path->nodes[0], extref, index); + btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid); + + ptr = (unsigned long)&extref->name; + write_extent_buffer(path->nodes[0], name, ptr, name_len); + btrfs_mark_buffer_dirty(path->nodes[0]); + +out: + btrfs_free_path(path); + return ret; +} + +/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */ +int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + const char *name, int name_len, + u64 inode_objectid, u64 ref_objectid, u64 index) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_inode_ref *ref; + unsigned long ptr; + int ret; + int ins_len = name_len + sizeof(*ref); + + key.objectid = inode_objectid; + key.offset = ref_objectid; + key.type = BTRFS_INODE_REF_KEY; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + path->skip_release_on_error = 1; + ret = btrfs_insert_empty_item(trans, root, path, &key, + ins_len); + if (ret == -EEXIST) { + u32 old_size; + + if (btrfs_find_name_in_backref(path->nodes[0], path->slots[0], + name, name_len, &ref)) + goto out; + + old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]); + btrfs_extend_item(fs_info, path, ins_len); + ref = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_inode_ref); + ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size); + btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len); + btrfs_set_inode_ref_index(path->nodes[0], ref, index); + ptr = (unsigned long)(ref + 1); + ret = 0; + } else if (ret < 0) { + if (ret == -EOVERFLOW) { + if (btrfs_find_name_in_backref(path->nodes[0], + path->slots[0], + name, name_len, &ref)) + ret = -EEXIST; + else + ret = -EMLINK; + } + goto out; + } else { + ref = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_inode_ref); + btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len); + btrfs_set_inode_ref_index(path->nodes[0], ref, index); + ptr = (unsigned long)(ref + 1); + } + write_extent_buffer(path->nodes[0], name, ptr, name_len); + btrfs_mark_buffer_dirty(path->nodes[0]); + +out: + btrfs_free_path(path); + + if (ret == -EMLINK) { + struct btrfs_super_block *disk_super = fs_info->super_copy; + /* We ran out of space in the ref array. Need to + * add an extended ref. */ + if (btrfs_super_incompat_flags(disk_super) + & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF) + ret = btrfs_insert_inode_extref(trans, root, name, + name_len, + inode_objectid, + ref_objectid, index); + } + + return ret; +} + +int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, u64 objectid) +{ + struct btrfs_key key; + int ret; + key.objectid = objectid; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + + ret = btrfs_insert_empty_item(trans, root, path, &key, + sizeof(struct btrfs_inode_item)); + return ret; +} + +int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root + *root, struct btrfs_path *path, + struct btrfs_key *location, int mod) +{ + int ins_len = mod < 0 ? -1 : 0; + int cow = mod != 0; + int ret; + int slot; + struct extent_buffer *leaf; + struct btrfs_key found_key; + + ret = btrfs_search_slot(trans, root, location, path, ins_len, cow); + if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY && + location->offset == (u64)-1 && path->slots[0] != 0) { + slot = path->slots[0] - 1; + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &found_key, slot); + if (found_key.objectid == location->objectid && + found_key.type == location->type) { + path->slots[0]--; + return 0; + } + } + return ret; +} |