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![Qu Wenruo](/assets/img/avatar_default.png)
In btrfs_lookup_path() the local variable @type should always be updated after we hit any file/dir. But if @filename is NULL from the very beginning, then we don't initialize it and return it directly. To prevent such problem from happening, we initialize @type to BTRFS_FT_UNKNOWN. For normal execution route, it will get updated for each filename we resolved. Buf if we didn't find any path, we check if the type is still FT_UNKNOWN and ret == 0. If true we know there is something wrong, just return -EUCLEAN to inform the caller. Reported-by: Coverity CID 312958 Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Marek Behún <marek.behun@nic.cz>
756 lines
18 KiB
C
756 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* BTRFS filesystem implementation for U-Boot
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*
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* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
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*/
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#include <linux/kernel.h>
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#include <malloc.h>
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#include <memalign.h>
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#include "btrfs.h"
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#include "disk-io.h"
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#include "volumes.h"
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/*
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* Read the content of symlink inode @ino of @root, into @target.
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* NOTE: @target will not be \0 termiated, caller should handle it properly.
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*
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* Return the number of read data.
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* Return <0 for error.
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*/
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int btrfs_readlink(struct btrfs_root *root, u64 ino, char *target)
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{
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struct btrfs_path path;
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struct btrfs_key key;
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struct btrfs_file_extent_item *fi;
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int ret;
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key.objectid = ino;
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = 0;
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btrfs_init_path(&path);
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ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
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if (ret < 0)
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return ret;
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if (ret > 0) {
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ret = -ENOENT;
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goto out;
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}
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fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
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struct btrfs_file_extent_item);
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if (btrfs_file_extent_type(path.nodes[0], fi) !=
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BTRFS_FILE_EXTENT_INLINE) {
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ret = -EUCLEAN;
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error("Extent for symlink %llu must be INLINE type!", ino);
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goto out;
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}
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if (btrfs_file_extent_compression(path.nodes[0], fi) !=
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BTRFS_COMPRESS_NONE) {
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ret = -EUCLEAN;
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error("Extent for symlink %llu must not be compressed!", ino);
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goto out;
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}
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if (btrfs_file_extent_ram_bytes(path.nodes[0], fi) >=
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root->fs_info->sectorsize) {
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ret = -EUCLEAN;
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error("Symlink %llu extent data too large (%llu)!\n",
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ino, btrfs_file_extent_ram_bytes(path.nodes[0], fi));
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goto out;
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}
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read_extent_buffer(path.nodes[0], target,
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btrfs_file_extent_inline_start(fi),
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btrfs_file_extent_ram_bytes(path.nodes[0], fi));
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ret = btrfs_file_extent_ram_bytes(path.nodes[0], fi);
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out:
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btrfs_release_path(&path);
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return ret;
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}
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static int lookup_root_ref(struct btrfs_fs_info *fs_info,
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u64 rootid, u64 *root_ret, u64 *dir_ret)
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{
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struct btrfs_root *root = fs_info->tree_root;
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struct btrfs_root_ref *root_ref;
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struct btrfs_path path;
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struct btrfs_key key;
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int ret;
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btrfs_init_path(&path);
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key.objectid = rootid;
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key.type = BTRFS_ROOT_BACKREF_KEY;
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key.offset = (u64)-1;
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ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
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if (ret < 0)
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return ret;
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/* Should not happen */
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if (ret == 0) {
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ret = -EUCLEAN;
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goto out;
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}
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ret = btrfs_previous_item(root, &path, rootid, BTRFS_ROOT_BACKREF_KEY);
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if (ret < 0)
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goto out;
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if (ret > 0) {
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ret = -ENOENT;
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goto out;
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}
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btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
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root_ref = btrfs_item_ptr(path.nodes[0], path.slots[0],
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struct btrfs_root_ref);
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*root_ret = key.offset;
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*dir_ret = btrfs_root_ref_dirid(path.nodes[0], root_ref);
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out:
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btrfs_release_path(&path);
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return ret;
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}
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/*
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* To get the parent inode of @ino of @root.
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*
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* @root_ret and @ino_ret will be filled.
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*
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* NOTE: This function is not reliable. It can only get one parent inode.
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* The get the proper parent inode, we need a full VFS inodes stack to
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* resolve properly.
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*/
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static int get_parent_inode(struct btrfs_root *root, u64 ino,
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struct btrfs_root **root_ret, u64 *ino_ret)
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_path path;
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struct btrfs_key key;
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int ret;
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if (ino == BTRFS_FIRST_FREE_OBJECTID) {
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u64 parent_root = -1;
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/* It's top level already, no more parent */
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if (root->root_key.objectid == BTRFS_FS_TREE_OBJECTID) {
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*root_ret = fs_info->fs_root;
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*ino_ret = BTRFS_FIRST_FREE_OBJECTID;
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return 0;
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}
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ret = lookup_root_ref(fs_info, root->root_key.objectid,
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&parent_root, ino_ret);
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if (ret < 0)
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return ret;
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key.objectid = parent_root;
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key.type = BTRFS_ROOT_ITEM_KEY;
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key.offset = (u64)-1;
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*root_ret = btrfs_read_fs_root(fs_info, &key);
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if (IS_ERR(*root_ret))
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return PTR_ERR(*root_ret);
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return 0;
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}
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btrfs_init_path(&path);
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key.objectid = ino;
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key.type = BTRFS_INODE_REF_KEY;
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key.offset = (u64)-1;
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ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
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if (ret < 0)
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return ret;
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/* Should not happen */
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if (ret == 0) {
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ret = -EUCLEAN;
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goto out;
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}
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ret = btrfs_previous_item(root, &path, ino, BTRFS_INODE_REF_KEY);
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if (ret < 0)
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goto out;
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if (ret > 0) {
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ret = -ENOENT;
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goto out;
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}
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btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
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*root_ret = root;
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*ino_ret = key.offset;
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out:
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btrfs_release_path(&path);
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return ret;
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}
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static inline int next_length(const char *path)
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{
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int res = 0;
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while (*path != '\0' && *path != '/') {
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++res;
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++path;
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if (res > BTRFS_NAME_LEN)
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break;
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}
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return res;
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}
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static inline const char *skip_current_directories(const char *cur)
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{
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while (1) {
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if (cur[0] == '/')
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++cur;
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else if (cur[0] == '.' && cur[1] == '/')
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cur += 2;
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else
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break;
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}
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return cur;
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}
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/*
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* Resolve one filename of @ino of @root.
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*
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* key_ret: The child key (either INODE_ITEM or ROOT_ITEM type)
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* type_ret: BTRFS_FT_* of the child inode.
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*
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* Return 0 with above members filled.
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* Return <0 for error.
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*/
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static int resolve_one_filename(struct btrfs_root *root, u64 ino,
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const char *name, int namelen,
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struct btrfs_key *key_ret, u8 *type_ret)
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{
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struct btrfs_dir_item *dir_item;
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struct btrfs_path path;
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int ret = 0;
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btrfs_init_path(&path);
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dir_item = btrfs_lookup_dir_item(NULL, root, &path, ino, name,
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namelen, 0);
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if (IS_ERR(dir_item)) {
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ret = PTR_ERR(dir_item);
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goto out;
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}
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btrfs_dir_item_key_to_cpu(path.nodes[0], dir_item, key_ret);
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*type_ret = btrfs_dir_type(path.nodes[0], dir_item);
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out:
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btrfs_release_path(&path);
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return ret;
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}
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/*
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* Resolve a full path @filename. The start point is @ino of @root.
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*
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* The result will be filled into @root_ret, @ino_ret and @type_ret.
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*/
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int btrfs_lookup_path(struct btrfs_root *root, u64 ino, const char *filename,
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struct btrfs_root **root_ret, u64 *ino_ret,
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u8 *type_ret, int symlink_limit)
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_root *next_root;
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struct btrfs_key key;
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const char *cur = filename;
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u64 next_ino;
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u8 next_type;
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u8 type = BTRFS_FT_UNKNOWN;
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int len;
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int ret = 0;
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/* If the path is absolute path, also search from fs root */
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if (*cur == '/') {
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root = fs_info->fs_root;
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ino = btrfs_root_dirid(&root->root_item);
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type = BTRFS_FT_DIR;
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}
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while (*cur != '\0') {
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cur = skip_current_directories(cur);
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len = next_length(cur);
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if (len > BTRFS_NAME_LEN) {
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error("%s: Name too long at \"%.*s\"", __func__,
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BTRFS_NAME_LEN, cur);
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return -ENAMETOOLONG;
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}
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if (len == 1 && cur[0] == '.')
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break;
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if (len == 2 && cur[0] == '.' && cur[1] == '.') {
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/* Go one level up */
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ret = get_parent_inode(root, ino, &next_root, &next_ino);
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if (ret < 0)
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return ret;
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root = next_root;
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ino = next_ino;
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goto next;
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}
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if (!*cur)
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break;
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ret = resolve_one_filename(root, ino, cur, len, &key, &type);
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if (ret < 0)
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return ret;
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if (key.type == BTRFS_ROOT_ITEM_KEY) {
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/* Child inode is a subvolume */
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next_root = btrfs_read_fs_root(fs_info, &key);
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if (IS_ERR(next_root))
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return PTR_ERR(next_root);
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root = next_root;
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ino = btrfs_root_dirid(&root->root_item);
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} else if (type == BTRFS_FT_SYMLINK && symlink_limit >= 0) {
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/* Child inode is a symlink */
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char *target;
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if (symlink_limit == 0) {
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error("%s: Too much symlinks!", __func__);
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return -EMLINK;
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}
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target = malloc(fs_info->sectorsize);
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if (!target)
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return -ENOMEM;
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ret = btrfs_readlink(root, key.objectid, target);
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if (ret < 0) {
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free(target);
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return ret;
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}
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target[ret] = '\0';
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ret = btrfs_lookup_path(root, ino, target, &next_root,
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&next_ino, &next_type,
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symlink_limit);
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if (ret < 0)
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return ret;
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root = next_root;
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ino = next_ino;
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type = next_type;
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} else {
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/* Child inode is an inode */
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ino = key.objectid;
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}
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next:
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cur += len;
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}
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/* We haven't found anything, but still get no error? */
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if (type == BTRFS_FT_UNKNOWN && !ret)
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ret = -EUCLEAN;
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if (!ret) {
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*root_ret = root;
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*ino_ret = ino;
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*type_ret = type;
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}
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return ret;
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}
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/*
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* Read out inline extent.
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*
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* Since inline extent should only exist for offset 0, no need for extra
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* parameters.
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* Truncating should be handled by the caller.
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*
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* Return the number of bytes read.
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* Return <0 for error.
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*/
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int btrfs_read_extent_inline(struct btrfs_path *path,
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struct btrfs_file_extent_item *fi, char *dest)
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{
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struct extent_buffer *leaf = path->nodes[0];
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int slot = path->slots[0];
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char *cbuf = NULL;
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char *dbuf = NULL;
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u32 csize;
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u32 dsize;
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int ret;
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csize = btrfs_file_extent_inline_item_len(leaf, btrfs_item_nr(slot));
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if (btrfs_file_extent_compression(leaf, fi) == BTRFS_COMPRESS_NONE) {
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/* Uncompressed, just read it out */
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read_extent_buffer(leaf, dest,
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btrfs_file_extent_inline_start(fi),
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csize);
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return csize;
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}
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/* Compressed extent, prepare the compressed and data buffer */
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dsize = btrfs_file_extent_ram_bytes(leaf, fi);
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cbuf = malloc(csize);
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dbuf = malloc(dsize);
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if (!cbuf || !dbuf) {
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ret = -ENOMEM;
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goto out;
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}
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read_extent_buffer(leaf, cbuf, btrfs_file_extent_inline_start(fi),
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csize);
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ret = btrfs_decompress(btrfs_file_extent_compression(leaf, fi),
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cbuf, csize, dbuf, dsize);
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if (ret < 0 || ret != dsize) {
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ret = -EIO;
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goto out;
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}
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memcpy(dest, dbuf, dsize);
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ret = dsize;
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out:
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free(cbuf);
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free(dbuf);
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return ret;
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}
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/*
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* Read out regular extent.
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*
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* Truncating should be handled by the caller.
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*
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* @offset and @len should not cross the extent boundary.
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* Return the number of bytes read.
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* Return <0 for error.
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*/
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int btrfs_read_extent_reg(struct btrfs_path *path,
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struct btrfs_file_extent_item *fi, u64 offset,
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int len, char *dest)
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{
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struct extent_buffer *leaf = path->nodes[0];
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struct btrfs_fs_info *fs_info = leaf->fs_info;
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struct btrfs_key key;
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u64 extent_num_bytes;
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u64 disk_bytenr;
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u64 read;
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char *cbuf = NULL;
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char *dbuf = NULL;
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u32 csize;
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u32 dsize;
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bool finished = false;
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int num_copies;
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int i;
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int slot = path->slots[0];
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int ret;
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btrfs_item_key_to_cpu(leaf, &key, slot);
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extent_num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
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ASSERT(IS_ALIGNED(offset, fs_info->sectorsize) &&
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IS_ALIGNED(len, fs_info->sectorsize));
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ASSERT(offset >= key.offset &&
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offset + len <= key.offset + extent_num_bytes);
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/* Preallocated or hole , fill @dest with zero */
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if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_PREALLOC ||
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btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
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memset(dest, 0, len);
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return len;
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}
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if (btrfs_file_extent_compression(leaf, fi) == BTRFS_COMPRESS_NONE) {
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u64 logical;
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logical = btrfs_file_extent_disk_bytenr(leaf, fi) +
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btrfs_file_extent_offset(leaf, fi) +
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offset - key.offset;
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read = len;
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num_copies = btrfs_num_copies(fs_info, logical, len);
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for (i = 1; i <= num_copies; i++) {
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ret = read_extent_data(fs_info, dest, logical, &read, i);
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if (ret < 0 || read != len)
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continue;
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finished = true;
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break;
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}
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if (!finished)
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return -EIO;
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return len;
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}
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csize = btrfs_file_extent_disk_num_bytes(leaf, fi);
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dsize = btrfs_file_extent_ram_bytes(leaf, fi);
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disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
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num_copies = btrfs_num_copies(fs_info, disk_bytenr, csize);
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cbuf = malloc_cache_aligned(csize);
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dbuf = malloc_cache_aligned(dsize);
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if (!cbuf || !dbuf) {
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ret = -ENOMEM;
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goto out;
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}
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/* For compressed extent, we must read the whole on-disk extent */
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for (i = 1; i <= num_copies; i++) {
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read = csize;
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ret = read_extent_data(fs_info, cbuf, disk_bytenr,
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&read, i);
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if (ret < 0 || read != csize)
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continue;
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finished = true;
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break;
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}
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if (!finished) {
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ret = -EIO;
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goto out;
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}
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|
|
ret = btrfs_decompress(btrfs_file_extent_compression(leaf, fi), cbuf,
|
|
csize, dbuf, dsize);
|
|
if (ret != dsize) {
|
|
ret = -EIO;
|
|
goto out;
|
|
}
|
|
/* Then copy the needed part */
|
|
memcpy(dest, dbuf + btrfs_file_extent_offset(leaf, fi), len);
|
|
ret = len;
|
|
out:
|
|
free(cbuf);
|
|
free(dbuf);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Get the first file extent that covers bytenr @file_offset.
|
|
*
|
|
* @file_offset must be aligned to sectorsize.
|
|
*
|
|
* return 0 for found, and path points to the file extent.
|
|
* return >0 for not found, and fill @next_offset.
|
|
* @next_offset can be 0 if there is no next file extent.
|
|
* return <0 for error.
|
|
*/
|
|
static int lookup_data_extent(struct btrfs_root *root, struct btrfs_path *path,
|
|
u64 ino, u64 file_offset, u64 *next_offset)
|
|
{
|
|
struct btrfs_key key;
|
|
struct btrfs_file_extent_item *fi;
|
|
u8 extent_type;
|
|
int ret = 0;
|
|
|
|
ASSERT(IS_ALIGNED(file_offset, root->fs_info->sectorsize));
|
|
key.objectid = ino;
|
|
key.type = BTRFS_EXTENT_DATA_KEY;
|
|
key.offset = file_offset;
|
|
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
/* Error or we're already at the file extent */
|
|
if (ret <= 0)
|
|
return ret;
|
|
if (ret > 0) {
|
|
/* Check previous file extent */
|
|
ret = btrfs_previous_item(root, path, ino,
|
|
BTRFS_EXTENT_DATA_KEY);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret > 0)
|
|
goto check_next;
|
|
}
|
|
/* Now the key.offset must be smaller than @file_offset */
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
|
|
if (key.objectid != ino ||
|
|
key.type != BTRFS_EXTENT_DATA_KEY)
|
|
goto check_next;
|
|
|
|
fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
|
|
struct btrfs_file_extent_item);
|
|
extent_type = btrfs_file_extent_type(path->nodes[0], fi);
|
|
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
|
|
if (file_offset == 0)
|
|
return 0;
|
|
/* Inline extent should be the only extent, no next extent. */
|
|
*next_offset = 0;
|
|
return 1;
|
|
}
|
|
|
|
/* This file extent covers @file_offset */
|
|
if (key.offset <= file_offset && key.offset +
|
|
btrfs_file_extent_num_bytes(path->nodes[0], fi) > file_offset)
|
|
return 0;
|
|
check_next:
|
|
ret = btrfs_next_item(root, path);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret > 0) {
|
|
*next_offset = 0;
|
|
return 1;
|
|
}
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
|
|
fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
|
|
struct btrfs_file_extent_item);
|
|
/* Next next data extent */
|
|
if (key.objectid != ino ||
|
|
key.type != BTRFS_EXTENT_DATA_KEY) {
|
|
*next_offset = 0;
|
|
return 1;
|
|
}
|
|
/* Current file extent already beyond @file_offset */
|
|
if (key.offset > file_offset) {
|
|
*next_offset = key.offset;
|
|
return 1;
|
|
}
|
|
/* This file extent covers @file_offset */
|
|
if (key.offset <= file_offset && key.offset +
|
|
btrfs_file_extent_num_bytes(path->nodes[0], fi) > file_offset)
|
|
return 0;
|
|
/* This file extent ends before @file_offset, check next */
|
|
ret = btrfs_next_item(root, path);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret > 0) {
|
|
*next_offset = 0;
|
|
return 1;
|
|
}
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
|
|
if (key.type != BTRFS_EXTENT_DATA_KEY || key.objectid != ino) {
|
|
*next_offset = 0;
|
|
return 1;
|
|
}
|
|
*next_offset = key.offset;
|
|
return 1;
|
|
}
|
|
|
|
static int read_and_truncate_page(struct btrfs_path *path,
|
|
struct btrfs_file_extent_item *fi,
|
|
int start, int len, char *dest)
|
|
{
|
|
struct extent_buffer *leaf = path->nodes[0];
|
|
struct btrfs_fs_info *fs_info = leaf->fs_info;
|
|
u64 aligned_start = round_down(start, fs_info->sectorsize);
|
|
u8 extent_type;
|
|
char *buf;
|
|
int page_off = start - aligned_start;
|
|
int page_len = fs_info->sectorsize - page_off;
|
|
int ret;
|
|
|
|
ASSERT(start + len <= aligned_start + fs_info->sectorsize);
|
|
buf = malloc_cache_aligned(fs_info->sectorsize);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
extent_type = btrfs_file_extent_type(leaf, fi);
|
|
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
|
|
ret = btrfs_read_extent_inline(path, fi, buf);
|
|
memcpy(dest, buf + page_off, min(page_len, ret));
|
|
free(buf);
|
|
return len;
|
|
}
|
|
|
|
ret = btrfs_read_extent_reg(path, fi,
|
|
round_down(start, fs_info->sectorsize),
|
|
fs_info->sectorsize, buf);
|
|
if (ret < 0) {
|
|
free(buf);
|
|
return ret;
|
|
}
|
|
memcpy(dest, buf + page_off, page_len);
|
|
free(buf);
|
|
return len;
|
|
}
|
|
|
|
int btrfs_file_read(struct btrfs_root *root, u64 ino, u64 file_offset, u64 len,
|
|
char *dest)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_file_extent_item *fi;
|
|
struct btrfs_path path;
|
|
struct btrfs_key key;
|
|
u64 aligned_start = round_down(file_offset, fs_info->sectorsize);
|
|
u64 aligned_end = round_down(file_offset + len, fs_info->sectorsize);
|
|
u64 next_offset;
|
|
u64 cur = aligned_start;
|
|
int ret = 0;
|
|
|
|
btrfs_init_path(&path);
|
|
|
|
/* Set the whole dest all zero, so we won't need to bother holes */
|
|
memset(dest, 0, len);
|
|
|
|
/* Read out the leading unaligned part */
|
|
if (aligned_start != file_offset) {
|
|
ret = lookup_data_extent(root, &path, ino, aligned_start,
|
|
&next_offset);
|
|
if (ret < 0)
|
|
goto out;
|
|
if (ret == 0) {
|
|
/* Read the unaligned part out*/
|
|
fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
|
|
struct btrfs_file_extent_item);
|
|
ret = read_and_truncate_page(&path, fi, file_offset,
|
|
round_up(file_offset, fs_info->sectorsize) -
|
|
file_offset, dest);
|
|
if (ret < 0)
|
|
goto out;
|
|
cur += fs_info->sectorsize;
|
|
} else {
|
|
/* The whole file is a hole */
|
|
if (!next_offset) {
|
|
memset(dest, 0, len);
|
|
return len;
|
|
}
|
|
cur = next_offset;
|
|
}
|
|
}
|
|
|
|
/* Read the aligned part */
|
|
while (cur < aligned_end) {
|
|
u64 extent_num_bytes;
|
|
u8 type;
|
|
|
|
btrfs_release_path(&path);
|
|
ret = lookup_data_extent(root, &path, ino, cur, &next_offset);
|
|
if (ret < 0)
|
|
goto out;
|
|
if (ret > 0) {
|
|
/* No next, direct exit */
|
|
if (!next_offset) {
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
}
|
|
fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
|
|
struct btrfs_file_extent_item);
|
|
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
|
|
type = btrfs_file_extent_type(path.nodes[0], fi);
|
|
if (type == BTRFS_FILE_EXTENT_INLINE) {
|
|
ret = btrfs_read_extent_inline(&path, fi, dest);
|
|
goto out;
|
|
}
|
|
/* Skip holes, as we have zeroed the dest */
|
|
if (type == BTRFS_FILE_EXTENT_PREALLOC ||
|
|
btrfs_file_extent_disk_bytenr(path.nodes[0], fi) == 0) {
|
|
cur = key.offset + btrfs_file_extent_num_bytes(
|
|
path.nodes[0], fi);
|
|
continue;
|
|
}
|
|
|
|
/* Read the remaining part of the extent */
|
|
extent_num_bytes = btrfs_file_extent_num_bytes(path.nodes[0],
|
|
fi);
|
|
ret = btrfs_read_extent_reg(&path, fi, cur,
|
|
min(extent_num_bytes, aligned_end - cur),
|
|
dest + cur - file_offset);
|
|
if (ret < 0)
|
|
goto out;
|
|
cur += min(extent_num_bytes, aligned_end - cur);
|
|
}
|
|
|
|
/* Read the tailing unaligned part*/
|
|
if (file_offset + len != aligned_end) {
|
|
btrfs_release_path(&path);
|
|
ret = lookup_data_extent(root, &path, ino, aligned_end,
|
|
&next_offset);
|
|
/* <0 is error, >0 means no extent */
|
|
if (ret)
|
|
goto out;
|
|
fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
|
|
struct btrfs_file_extent_item);
|
|
ret = read_and_truncate_page(&path, fi, aligned_end,
|
|
file_offset + len - aligned_end,
|
|
dest + aligned_end - file_offset);
|
|
}
|
|
out:
|
|
btrfs_release_path(&path);
|
|
if (ret < 0)
|
|
return ret;
|
|
return len;
|
|
}
|