![Chris Mason](/assets/img/avatar_default.png)
The new ioctls to follow backrefs are not clean for 32/64 bit compat. This reworks them for u64s everywhere. They are brand new, so there are no problems with changing the interface now. Signed-off-by: Chris Mason <chris.mason@oracle.com>
777 lines
20 KiB
C
777 lines
20 KiB
C
/*
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* Copyright (C) 2011 STRATO. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include "ctree.h"
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#include "disk-io.h"
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#include "backref.h"
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struct __data_ref {
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struct list_head list;
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u64 inum;
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u64 root;
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u64 extent_data_item_offset;
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};
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struct __shared_ref {
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struct list_head list;
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u64 disk_byte;
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};
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static int __inode_info(u64 inum, u64 ioff, u8 key_type,
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struct btrfs_root *fs_root, struct btrfs_path *path,
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struct btrfs_key *found_key)
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{
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int ret;
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struct btrfs_key key;
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struct extent_buffer *eb;
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key.type = key_type;
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key.objectid = inum;
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key.offset = ioff;
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ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
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if (ret < 0)
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return ret;
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eb = path->nodes[0];
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if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
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ret = btrfs_next_leaf(fs_root, path);
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if (ret)
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return ret;
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eb = path->nodes[0];
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}
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btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
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if (found_key->type != key.type || found_key->objectid != key.objectid)
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return 1;
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return 0;
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}
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/*
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* this makes the path point to (inum INODE_ITEM ioff)
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*/
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int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
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struct btrfs_path *path)
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{
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struct btrfs_key key;
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return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path,
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&key);
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}
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static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
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struct btrfs_path *path,
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struct btrfs_key *found_key)
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{
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return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path,
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found_key);
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}
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/*
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* this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
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* of the path are separated by '/' and the path is guaranteed to be
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* 0-terminated. the path is only given within the current file system.
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* Therefore, it never starts with a '/'. the caller is responsible to provide
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* "size" bytes in "dest". the dest buffer will be filled backwards. finally,
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* the start point of the resulting string is returned. this pointer is within
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* dest, normally.
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* in case the path buffer would overflow, the pointer is decremented further
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* as if output was written to the buffer, though no more output is actually
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* generated. that way, the caller can determine how much space would be
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* required for the path to fit into the buffer. in that case, the returned
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* value will be smaller than dest. callers must check this!
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*/
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static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
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struct btrfs_inode_ref *iref,
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struct extent_buffer *eb_in, u64 parent,
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char *dest, u32 size)
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{
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u32 len;
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int slot;
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u64 next_inum;
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int ret;
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s64 bytes_left = size - 1;
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struct extent_buffer *eb = eb_in;
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struct btrfs_key found_key;
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if (bytes_left >= 0)
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dest[bytes_left] = '\0';
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while (1) {
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len = btrfs_inode_ref_name_len(eb, iref);
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bytes_left -= len;
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if (bytes_left >= 0)
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read_extent_buffer(eb, dest + bytes_left,
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(unsigned long)(iref + 1), len);
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if (eb != eb_in)
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free_extent_buffer(eb);
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ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
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if (ret)
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break;
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next_inum = found_key.offset;
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/* regular exit ahead */
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if (parent == next_inum)
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break;
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slot = path->slots[0];
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eb = path->nodes[0];
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/* make sure we can use eb after releasing the path */
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if (eb != eb_in)
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atomic_inc(&eb->refs);
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btrfs_release_path(path);
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iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
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parent = next_inum;
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--bytes_left;
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if (bytes_left >= 0)
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dest[bytes_left] = '/';
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}
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btrfs_release_path(path);
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if (ret)
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return ERR_PTR(ret);
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return dest + bytes_left;
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}
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/*
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* this makes the path point to (logical EXTENT_ITEM *)
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* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
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* tree blocks and <0 on error.
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*/
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int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
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struct btrfs_path *path, struct btrfs_key *found_key)
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{
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int ret;
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u64 flags;
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u32 item_size;
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struct extent_buffer *eb;
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struct btrfs_extent_item *ei;
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struct btrfs_key key;
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key.type = BTRFS_EXTENT_ITEM_KEY;
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key.objectid = logical;
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key.offset = (u64)-1;
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ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
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if (ret < 0)
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return ret;
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ret = btrfs_previous_item(fs_info->extent_root, path,
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0, BTRFS_EXTENT_ITEM_KEY);
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if (ret < 0)
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return ret;
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btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
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if (found_key->type != BTRFS_EXTENT_ITEM_KEY ||
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found_key->objectid > logical ||
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found_key->objectid + found_key->offset <= logical)
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return -ENOENT;
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eb = path->nodes[0];
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item_size = btrfs_item_size_nr(eb, path->slots[0]);
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BUG_ON(item_size < sizeof(*ei));
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ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
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flags = btrfs_extent_flags(eb, ei);
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if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
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return BTRFS_EXTENT_FLAG_TREE_BLOCK;
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if (flags & BTRFS_EXTENT_FLAG_DATA)
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return BTRFS_EXTENT_FLAG_DATA;
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return -EIO;
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}
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/*
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* helper function to iterate extent inline refs. ptr must point to a 0 value
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* for the first call and may be modified. it is used to track state.
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* if more refs exist, 0 is returned and the next call to
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* __get_extent_inline_ref must pass the modified ptr parameter to get the
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* next ref. after the last ref was processed, 1 is returned.
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* returns <0 on error
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*/
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static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
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struct btrfs_extent_item *ei, u32 item_size,
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struct btrfs_extent_inline_ref **out_eiref,
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int *out_type)
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{
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unsigned long end;
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u64 flags;
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struct btrfs_tree_block_info *info;
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if (!*ptr) {
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/* first call */
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flags = btrfs_extent_flags(eb, ei);
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if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
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info = (struct btrfs_tree_block_info *)(ei + 1);
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*out_eiref =
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(struct btrfs_extent_inline_ref *)(info + 1);
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} else {
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*out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
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}
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*ptr = (unsigned long)*out_eiref;
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if ((void *)*ptr >= (void *)ei + item_size)
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return -ENOENT;
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}
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end = (unsigned long)ei + item_size;
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*out_eiref = (struct btrfs_extent_inline_ref *)*ptr;
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*out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
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*ptr += btrfs_extent_inline_ref_size(*out_type);
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WARN_ON(*ptr > end);
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if (*ptr == end)
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return 1; /* last */
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return 0;
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}
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/*
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* reads the tree block backref for an extent. tree level and root are returned
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* through out_level and out_root. ptr must point to a 0 value for the first
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* call and may be modified (see __get_extent_inline_ref comment).
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* returns 0 if data was provided, 1 if there was no more data to provide or
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* <0 on error.
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*/
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int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
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struct btrfs_extent_item *ei, u32 item_size,
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u64 *out_root, u8 *out_level)
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{
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int ret;
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int type;
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struct btrfs_tree_block_info *info;
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struct btrfs_extent_inline_ref *eiref;
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if (*ptr == (unsigned long)-1)
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return 1;
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while (1) {
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ret = __get_extent_inline_ref(ptr, eb, ei, item_size,
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&eiref, &type);
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if (ret < 0)
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return ret;
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if (type == BTRFS_TREE_BLOCK_REF_KEY ||
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type == BTRFS_SHARED_BLOCK_REF_KEY)
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break;
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if (ret == 1)
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return 1;
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}
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/* we can treat both ref types equally here */
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info = (struct btrfs_tree_block_info *)(ei + 1);
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*out_root = btrfs_extent_inline_ref_offset(eb, eiref);
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*out_level = btrfs_tree_block_level(eb, info);
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if (ret == 1)
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*ptr = (unsigned long)-1;
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return 0;
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}
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static int __data_list_add(struct list_head *head, u64 inum,
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u64 extent_data_item_offset, u64 root)
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{
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struct __data_ref *ref;
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ref = kmalloc(sizeof(*ref), GFP_NOFS);
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if (!ref)
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return -ENOMEM;
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ref->inum = inum;
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ref->extent_data_item_offset = extent_data_item_offset;
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ref->root = root;
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list_add_tail(&ref->list, head);
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return 0;
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}
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static int __data_list_add_eb(struct list_head *head, struct extent_buffer *eb,
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struct btrfs_extent_data_ref *dref)
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{
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return __data_list_add(head, btrfs_extent_data_ref_objectid(eb, dref),
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btrfs_extent_data_ref_offset(eb, dref),
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btrfs_extent_data_ref_root(eb, dref));
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}
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static int __shared_list_add(struct list_head *head, u64 disk_byte)
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{
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struct __shared_ref *ref;
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ref = kmalloc(sizeof(*ref), GFP_NOFS);
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if (!ref)
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return -ENOMEM;
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ref->disk_byte = disk_byte;
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list_add_tail(&ref->list, head);
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return 0;
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}
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static int __iter_shared_inline_ref_inodes(struct btrfs_fs_info *fs_info,
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u64 logical, u64 inum,
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u64 extent_data_item_offset,
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u64 extent_offset,
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struct btrfs_path *path,
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struct list_head *data_refs,
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iterate_extent_inodes_t *iterate,
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void *ctx)
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{
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u64 ref_root;
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u32 item_size;
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struct btrfs_key key;
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struct extent_buffer *eb;
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struct btrfs_extent_item *ei;
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struct btrfs_extent_inline_ref *eiref;
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struct __data_ref *ref;
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int ret;
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int type;
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int last;
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unsigned long ptr = 0;
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WARN_ON(!list_empty(data_refs));
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ret = extent_from_logical(fs_info, logical, path, &key);
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if (ret & BTRFS_EXTENT_FLAG_DATA)
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ret = -EIO;
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if (ret < 0)
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goto out;
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eb = path->nodes[0];
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ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
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item_size = btrfs_item_size_nr(eb, path->slots[0]);
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ret = 0;
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ref_root = 0;
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/*
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* as done in iterate_extent_inodes, we first build a list of refs to
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* iterate, then free the path and then iterate them to avoid deadlocks.
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*/
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do {
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last = __get_extent_inline_ref(&ptr, eb, ei, item_size,
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&eiref, &type);
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if (last < 0) {
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ret = last;
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goto out;
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}
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if (type == BTRFS_TREE_BLOCK_REF_KEY ||
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type == BTRFS_SHARED_BLOCK_REF_KEY) {
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ref_root = btrfs_extent_inline_ref_offset(eb, eiref);
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ret = __data_list_add(data_refs, inum,
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extent_data_item_offset,
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ref_root);
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}
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} while (!ret && !last);
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btrfs_release_path(path);
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if (ref_root == 0) {
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printk(KERN_ERR "btrfs: failed to find tree block ref "
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"for shared data backref %llu\n", logical);
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WARN_ON(1);
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ret = -EIO;
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}
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out:
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while (!list_empty(data_refs)) {
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ref = list_first_entry(data_refs, struct __data_ref, list);
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list_del(&ref->list);
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if (!ret)
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ret = iterate(ref->inum, extent_offset +
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ref->extent_data_item_offset,
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ref->root, ctx);
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kfree(ref);
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}
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return ret;
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}
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static int __iter_shared_inline_ref(struct btrfs_fs_info *fs_info,
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u64 logical, u64 orig_extent_item_objectid,
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u64 extent_offset, struct btrfs_path *path,
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struct list_head *data_refs,
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iterate_extent_inodes_t *iterate,
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void *ctx)
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{
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u64 disk_byte;
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struct btrfs_key key;
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struct btrfs_file_extent_item *fi;
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struct extent_buffer *eb;
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int slot;
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int nritems;
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int ret;
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int found = 0;
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eb = read_tree_block(fs_info->tree_root, logical,
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fs_info->tree_root->leafsize, 0);
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if (!eb)
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return -EIO;
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/*
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* from the shared data ref, we only have the leaf but we need
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* the key. thus, we must look into all items and see that we
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* find one (some) with a reference to our extent item.
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*/
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nritems = btrfs_header_nritems(eb);
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for (slot = 0; slot < nritems; ++slot) {
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btrfs_item_key_to_cpu(eb, &key, slot);
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if (key.type != BTRFS_EXTENT_DATA_KEY)
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continue;
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fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
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if (!fi) {
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free_extent_buffer(eb);
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return -EIO;
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}
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disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
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if (disk_byte != orig_extent_item_objectid) {
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if (found)
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break;
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else
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continue;
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}
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++found;
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ret = __iter_shared_inline_ref_inodes(fs_info, logical,
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key.objectid,
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key.offset,
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extent_offset, path,
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data_refs,
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iterate, ctx);
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if (ret)
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break;
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}
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if (!found) {
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printk(KERN_ERR "btrfs: failed to follow shared data backref "
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"to parent %llu\n", logical);
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WARN_ON(1);
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ret = -EIO;
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}
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free_extent_buffer(eb);
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return ret;
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}
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/*
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* calls iterate() for every inode that references the extent identified by
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* the given parameters. will use the path given as a parameter and return it
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* released.
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* when the iterator function returns a non-zero value, iteration stops.
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*/
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int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
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struct btrfs_path *path,
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u64 extent_item_objectid,
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u64 extent_offset,
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iterate_extent_inodes_t *iterate, void *ctx)
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{
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unsigned long ptr = 0;
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int last;
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int ret;
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int type;
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u64 logical;
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u32 item_size;
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struct btrfs_extent_inline_ref *eiref;
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struct btrfs_extent_data_ref *dref;
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struct extent_buffer *eb;
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struct btrfs_extent_item *ei;
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struct btrfs_key key;
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struct list_head data_refs = LIST_HEAD_INIT(data_refs);
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struct list_head shared_refs = LIST_HEAD_INIT(shared_refs);
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struct __data_ref *ref_d;
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struct __shared_ref *ref_s;
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|
|
|
eb = path->nodes[0];
|
|
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
|
|
item_size = btrfs_item_size_nr(eb, path->slots[0]);
|
|
|
|
/* first we iterate the inline refs, ... */
|
|
do {
|
|
last = __get_extent_inline_ref(&ptr, eb, ei, item_size,
|
|
&eiref, &type);
|
|
if (last == -ENOENT) {
|
|
ret = 0;
|
|
break;
|
|
}
|
|
if (last < 0) {
|
|
ret = last;
|
|
break;
|
|
}
|
|
|
|
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
|
|
dref = (struct btrfs_extent_data_ref *)(&eiref->offset);
|
|
ret = __data_list_add_eb(&data_refs, eb, dref);
|
|
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
|
|
logical = btrfs_extent_inline_ref_offset(eb, eiref);
|
|
ret = __shared_list_add(&shared_refs, logical);
|
|
}
|
|
} while (!ret && !last);
|
|
|
|
/* ... then we proceed to in-tree references and ... */
|
|
while (!ret) {
|
|
++path->slots[0];
|
|
if (path->slots[0] > btrfs_header_nritems(eb)) {
|
|
ret = btrfs_next_leaf(fs_info->extent_root, path);
|
|
if (ret) {
|
|
if (ret == 1)
|
|
ret = 0; /* we're done */
|
|
break;
|
|
}
|
|
eb = path->nodes[0];
|
|
}
|
|
btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
|
|
if (key.objectid != extent_item_objectid)
|
|
break;
|
|
if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
|
|
dref = btrfs_item_ptr(eb, path->slots[0],
|
|
struct btrfs_extent_data_ref);
|
|
ret = __data_list_add_eb(&data_refs, eb, dref);
|
|
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
|
|
ret = __shared_list_add(&shared_refs, key.offset);
|
|
}
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
/*
|
|
* ... only at the very end we can process the refs we found. this is
|
|
* because the iterator function we call is allowed to make tree lookups
|
|
* and we have to avoid deadlocks. additionally, we need more tree
|
|
* lookups ourselves for shared data refs.
|
|
*/
|
|
while (!list_empty(&data_refs)) {
|
|
ref_d = list_first_entry(&data_refs, struct __data_ref, list);
|
|
list_del(&ref_d->list);
|
|
if (!ret)
|
|
ret = iterate(ref_d->inum, extent_offset +
|
|
ref_d->extent_data_item_offset,
|
|
ref_d->root, ctx);
|
|
kfree(ref_d);
|
|
}
|
|
|
|
while (!list_empty(&shared_refs)) {
|
|
ref_s = list_first_entry(&shared_refs, struct __shared_ref,
|
|
list);
|
|
list_del(&ref_s->list);
|
|
if (!ret)
|
|
ret = __iter_shared_inline_ref(fs_info,
|
|
ref_s->disk_byte,
|
|
extent_item_objectid,
|
|
extent_offset, path,
|
|
&data_refs,
|
|
iterate, ctx);
|
|
kfree(ref_s);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
iterate_extent_inodes_t *iterate, void *ctx)
|
|
{
|
|
int ret;
|
|
u64 offset;
|
|
struct btrfs_key found_key;
|
|
|
|
ret = extent_from_logical(fs_info, logical, path,
|
|
&found_key);
|
|
if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
|
|
ret = -EINVAL;
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
offset = logical - found_key.objectid;
|
|
ret = iterate_extent_inodes(fs_info, path, found_key.objectid,
|
|
offset, iterate, ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path,
|
|
iterate_irefs_t *iterate, void *ctx)
|
|
{
|
|
int ret;
|
|
int slot;
|
|
u32 cur;
|
|
u32 len;
|
|
u32 name_len;
|
|
u64 parent = 0;
|
|
int found = 0;
|
|
struct extent_buffer *eb;
|
|
struct btrfs_item *item;
|
|
struct btrfs_inode_ref *iref;
|
|
struct btrfs_key found_key;
|
|
|
|
while (1) {
|
|
ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
|
|
&found_key);
|
|
if (ret < 0)
|
|
break;
|
|
if (ret) {
|
|
ret = found ? 0 : -ENOENT;
|
|
break;
|
|
}
|
|
++found;
|
|
|
|
parent = found_key.offset;
|
|
slot = path->slots[0];
|
|
eb = path->nodes[0];
|
|
/* make sure we can use eb after releasing the path */
|
|
atomic_inc(&eb->refs);
|
|
btrfs_release_path(path);
|
|
|
|
item = btrfs_item_nr(eb, slot);
|
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
|
|
|
|
for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
|
|
name_len = btrfs_inode_ref_name_len(eb, iref);
|
|
/* path must be released before calling iterate()! */
|
|
ret = iterate(parent, iref, eb, ctx);
|
|
if (ret) {
|
|
free_extent_buffer(eb);
|
|
break;
|
|
}
|
|
len = sizeof(*iref) + name_len;
|
|
iref = (struct btrfs_inode_ref *)((char *)iref + len);
|
|
}
|
|
free_extent_buffer(eb);
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* returns 0 if the path could be dumped (probably truncated)
|
|
* returns <0 in case of an error
|
|
*/
|
|
static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref,
|
|
struct extent_buffer *eb, void *ctx)
|
|
{
|
|
struct inode_fs_paths *ipath = ctx;
|
|
char *fspath;
|
|
char *fspath_min;
|
|
int i = ipath->fspath->elem_cnt;
|
|
const int s_ptr = sizeof(char *);
|
|
u32 bytes_left;
|
|
|
|
bytes_left = ipath->fspath->bytes_left > s_ptr ?
|
|
ipath->fspath->bytes_left - s_ptr : 0;
|
|
|
|
fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
|
|
fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb,
|
|
inum, fspath_min, bytes_left);
|
|
if (IS_ERR(fspath))
|
|
return PTR_ERR(fspath);
|
|
|
|
if (fspath > fspath_min) {
|
|
ipath->fspath->val[i] = (u64)fspath;
|
|
++ipath->fspath->elem_cnt;
|
|
ipath->fspath->bytes_left = fspath - fspath_min;
|
|
} else {
|
|
++ipath->fspath->elem_missed;
|
|
ipath->fspath->bytes_missing += fspath_min - fspath;
|
|
ipath->fspath->bytes_left = 0;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* this dumps all file system paths to the inode into the ipath struct, provided
|
|
* is has been created large enough. each path is zero-terminated and accessed
|
|
* from ipath->fspath->val[i].
|
|
* when it returns, there are ipath->fspath->elem_cnt number of paths available
|
|
* in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
|
|
* number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
|
|
* it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
|
|
* have been needed to return all paths.
|
|
*/
|
|
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
|
|
{
|
|
return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
|
|
inode_to_path, ipath);
|
|
}
|
|
|
|
/*
|
|
* allocates space to return multiple file system paths for an inode.
|
|
* total_bytes to allocate are passed, note that space usable for actual path
|
|
* information will be total_bytes - sizeof(struct inode_fs_paths).
|
|
* the returned pointer must be freed with free_ipath() in the end.
|
|
*/
|
|
struct btrfs_data_container *init_data_container(u32 total_bytes)
|
|
{
|
|
struct btrfs_data_container *data;
|
|
size_t alloc_bytes;
|
|
|
|
alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
|
|
data = kmalloc(alloc_bytes, GFP_NOFS);
|
|
if (!data)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (total_bytes >= sizeof(*data)) {
|
|
data->bytes_left = total_bytes - sizeof(*data);
|
|
data->bytes_missing = 0;
|
|
} else {
|
|
data->bytes_missing = sizeof(*data) - total_bytes;
|
|
data->bytes_left = 0;
|
|
}
|
|
|
|
data->elem_cnt = 0;
|
|
data->elem_missed = 0;
|
|
|
|
return data;
|
|
}
|
|
|
|
/*
|
|
* allocates space to return multiple file system paths for an inode.
|
|
* total_bytes to allocate are passed, note that space usable for actual path
|
|
* information will be total_bytes - sizeof(struct inode_fs_paths).
|
|
* the returned pointer must be freed with free_ipath() in the end.
|
|
*/
|
|
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
|
|
struct btrfs_path *path)
|
|
{
|
|
struct inode_fs_paths *ifp;
|
|
struct btrfs_data_container *fspath;
|
|
|
|
fspath = init_data_container(total_bytes);
|
|
if (IS_ERR(fspath))
|
|
return (void *)fspath;
|
|
|
|
ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
|
|
if (!ifp) {
|
|
kfree(fspath);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
ifp->btrfs_path = path;
|
|
ifp->fspath = fspath;
|
|
ifp->fs_root = fs_root;
|
|
|
|
return ifp;
|
|
}
|
|
|
|
void free_ipath(struct inode_fs_paths *ipath)
|
|
{
|
|
kfree(ipath);
|
|
}
|