Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad...

[zen-stable.git] / fs / btrfs / backref.c

/*
 * Copyright (C) 2011 STRATO.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include "ctree.h"
#include "disk-io.h"
#include "backref.h"

struct __data_ref {
        struct list_head list;
        u64 inum;
        u64 root;
        u64 extent_data_item_offset;
};

struct __shared_ref {
        struct list_head list;
        u64 disk_byte;
};

static int __inode_info(u64 inum, u64 ioff, u8 key_type,
                        struct btrfs_root *fs_root, struct btrfs_path *path,
                        struct btrfs_key *found_key)
{
        int ret;
        struct btrfs_key key;
        struct extent_buffer *eb;

        key.type = key_type;
        key.objectid = inum;
        key.offset = ioff;

        ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
        if (ret < 0)
                return ret;

        eb = path->nodes[0];
        if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
                ret = btrfs_next_leaf(fs_root, path);
                if (ret)
                        return ret;
                eb = path->nodes[0];
        }

        btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
        if (found_key->type != key.type || found_key->objectid != key.objectid)
                return 1;

        return 0;
}

/*
 * this makes the path point to (inum INODE_ITEM ioff)
 */
int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
                        struct btrfs_path *path)
{
        struct btrfs_key key;
        return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path,
                                &key);
}

static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
                                struct btrfs_path *path,
                                struct btrfs_key *found_key)
{
        return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path,
                                found_key);
}

/*
 * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
 * of the path are separated by '/' and the path is guaranteed to be
 * 0-terminated. the path is only given within the current file system.
 * Therefore, it never starts with a '/'. the caller is responsible to provide
 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
 * the start point of the resulting string is returned. this pointer is within
 * dest, normally.
 * in case the path buffer would overflow, the pointer is decremented further
 * as if output was written to the buffer, though no more output is actually
 * generated. that way, the caller can determine how much space would be
 * required for the path to fit into the buffer. in that case, the returned
 * value will be smaller than dest. callers must check this!
 */
static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
                                struct btrfs_inode_ref *iref,
                                struct extent_buffer *eb_in, u64 parent,
                                char *dest, u32 size)
{
        u32 len;
        int slot;
        u64 next_inum;
        int ret;
        s64 bytes_left = size - 1;
        struct extent_buffer *eb = eb_in;
        struct btrfs_key found_key;

        if (bytes_left >= 0)
                dest[bytes_left] = '\0';

        while (1) {
                len = btrfs_inode_ref_name_len(eb, iref);
                bytes_left -= len;
                if (bytes_left >= 0)
                        read_extent_buffer(eb, dest + bytes_left,
                                                (unsigned long)(iref + 1), len);
                if (eb != eb_in)
                        free_extent_buffer(eb);
                ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
                if (ret)
                        break;
                next_inum = found_key.offset;

                /* regular exit ahead */
                if (parent == next_inum)
                        break;

                slot = path->slots[0];
                eb = path->nodes[0];
                /* make sure we can use eb after releasing the path */
                if (eb != eb_in)
                        atomic_inc(&eb->refs);
                btrfs_release_path(path);

                iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
                parent = next_inum;
                --bytes_left;
                if (bytes_left >= 0)
                        dest[bytes_left] = '/';
        }

        btrfs_release_path(path);

        if (ret)
                return ERR_PTR(ret);

        return dest + bytes_left;
}

/*
 * this makes the path point to (logical EXTENT_ITEM *)
 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
 * tree blocks and <0 on error.
 */
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
                        struct btrfs_path *path, struct btrfs_key *found_key)
{
        int ret;
        u64 flags;
        u32 item_size;
        struct extent_buffer *eb;
        struct btrfs_extent_item *ei;
        struct btrfs_key key;

        key.type = BTRFS_EXTENT_ITEM_KEY;
        key.objectid = logical;
        key.offset = (u64)-1;

        ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
        if (ret < 0)
                return ret;
        ret = btrfs_previous_item(fs_info->extent_root, path,
                                        0, BTRFS_EXTENT_ITEM_KEY);
        if (ret < 0)
                return ret;

        btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
        if (found_key->type != BTRFS_EXTENT_ITEM_KEY ||
            found_key->objectid > logical ||
            found_key->objectid + found_key->offset <= logical)
                return -ENOENT;

        eb = path->nodes[0];
        item_size = btrfs_item_size_nr(eb, path->slots[0]);
        BUG_ON(item_size < sizeof(*ei));

        ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
        flags = btrfs_extent_flags(eb, ei);

        if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
                return BTRFS_EXTENT_FLAG_TREE_BLOCK;
        if (flags & BTRFS_EXTENT_FLAG_DATA)
                return BTRFS_EXTENT_FLAG_DATA;

        return -EIO;
}

/*
 * helper function to iterate extent inline refs. ptr must point to a 0 value
 * for the first call and may be modified. it is used to track state.
 * if more refs exist, 0 is returned and the next call to
 * __get_extent_inline_ref must pass the modified ptr parameter to get the
 * next ref. after the last ref was processed, 1 is returned.
 * returns <0 on error
 */
static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
                                struct btrfs_extent_item *ei, u32 item_size,
                                struct btrfs_extent_inline_ref **out_eiref,
                                int *out_type)
{
        unsigned long end;
        u64 flags;
        struct btrfs_tree_block_info *info;

        if (!*ptr) {
                /* first call */
                flags = btrfs_extent_flags(eb, ei);
                if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
                        info = (struct btrfs_tree_block_info *)(ei + 1);
                        *out_eiref =
                                (struct btrfs_extent_inline_ref *)(info + 1);
                } else {
                        *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
                }
                *ptr = (unsigned long)*out_eiref;
                if ((void *)*ptr >= (void *)ei + item_size)
                        return -ENOENT;
        }

        end = (unsigned long)ei + item_size;
        *out_eiref = (struct btrfs_extent_inline_ref *)*ptr;
        *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);

        *ptr += btrfs_extent_inline_ref_size(*out_type);
        WARN_ON(*ptr > end);
        if (*ptr == end)
                return 1; /* last */

        return 0;
}

/*
 * reads the tree block backref for an extent. tree level and root are returned
 * through out_level and out_root. ptr must point to a 0 value for the first
 * call and may be modified (see __get_extent_inline_ref comment).
 * returns 0 if data was provided, 1 if there was no more data to provide or
 * <0 on error.
 */
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
                                struct btrfs_extent_item *ei, u32 item_size,
                                u64 *out_root, u8 *out_level)
{
        int ret;
        int type;
        struct btrfs_tree_block_info *info;
        struct btrfs_extent_inline_ref *eiref;

        if (*ptr == (unsigned long)-1)
                return 1;

        while (1) {
                ret = __get_extent_inline_ref(ptr, eb, ei, item_size,
                                                &eiref, &type);
                if (ret < 0)
                        return ret;

                if (type == BTRFS_TREE_BLOCK_REF_KEY ||
                    type == BTRFS_SHARED_BLOCK_REF_KEY)
                        break;

                if (ret == 1)
                        return 1;
        }

        /* we can treat both ref types equally here */
        info = (struct btrfs_tree_block_info *)(ei + 1);
        *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
        *out_level = btrfs_tree_block_level(eb, info);

        if (ret == 1)
                *ptr = (unsigned long)-1;

        return 0;
}

static int __data_list_add(struct list_head *head, u64 inum,
                                u64 extent_data_item_offset, u64 root)
{
        struct __data_ref *ref;

        ref = kmalloc(sizeof(*ref), GFP_NOFS);
        if (!ref)
                return -ENOMEM;

        ref->inum = inum;
        ref->extent_data_item_offset = extent_data_item_offset;
        ref->root = root;
        list_add_tail(&ref->list, head);

        return 0;
}

static int __data_list_add_eb(struct list_head *head, struct extent_buffer *eb,
                                struct btrfs_extent_data_ref *dref)
{
        return __data_list_add(head, btrfs_extent_data_ref_objectid(eb, dref),
                                btrfs_extent_data_ref_offset(eb, dref),
                                btrfs_extent_data_ref_root(eb, dref));
}

static int __shared_list_add(struct list_head *head, u64 disk_byte)
{
        struct __shared_ref *ref;

        ref = kmalloc(sizeof(*ref), GFP_NOFS);
        if (!ref)
                return -ENOMEM;

        ref->disk_byte = disk_byte;
        list_add_tail(&ref->list, head);

        return 0;
}

static int __iter_shared_inline_ref_inodes(struct btrfs_fs_info *fs_info,
                                           u64 logical, u64 inum,
                                           u64 extent_data_item_offset,
                                           u64 extent_offset,
                                           struct btrfs_path *path,
                                           struct list_head *data_refs,
                                           iterate_extent_inodes_t *iterate,
                                           void *ctx)
{
        u64 ref_root;
        u32 item_size;
        struct btrfs_key key;
        struct extent_buffer *eb;
        struct btrfs_extent_item *ei;
        struct btrfs_extent_inline_ref *eiref;
        struct __data_ref *ref;
        int ret;
        int type;
        int last;
        unsigned long ptr = 0;

        WARN_ON(!list_empty(data_refs));
        ret = extent_from_logical(fs_info, logical, path, &key);
        if (ret & BTRFS_EXTENT_FLAG_DATA)
                ret = -EIO;
        if (ret < 0)
                goto out;

        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]);

        ret = 0;
        ref_root = 0;
        /*
         * as done in iterate_extent_inodes, we first build a list of refs to
         * iterate, then free the path and then iterate them to avoid deadlocks.
         */
        do {
                last = __get_extent_inline_ref(&ptr, eb, ei, item_size,
                                                &eiref, &type);
                if (last < 0) {
                        ret = last;
                        goto out;
                }
                if (type == BTRFS_TREE_BLOCK_REF_KEY ||
                    type == BTRFS_SHARED_BLOCK_REF_KEY) {
                        ref_root = btrfs_extent_inline_ref_offset(eb, eiref);
                        ret = __data_list_add(data_refs, inum,
                                                extent_data_item_offset,
                                                ref_root);
                }
        } while (!ret && !last);

        btrfs_release_path(path);

        if (ref_root == 0) {
                printk(KERN_ERR "btrfs: failed to find tree block ref "
                        "for shared data backref %llu\n", logical);
                WARN_ON(1);
                ret = -EIO;
        }

out:
        while (!list_empty(data_refs)) {
                ref = list_first_entry(data_refs, struct __data_ref, list);
                list_del(&ref->list);
                if (!ret)
                        ret = iterate(ref->inum, extent_offset +
                                        ref->extent_data_item_offset,
                                        ref->root, ctx);
                kfree(ref);
        }

        return ret;
}

static int __iter_shared_inline_ref(struct btrfs_fs_info *fs_info,
                                    u64 logical, u64 orig_extent_item_objectid,
                                    u64 extent_offset, struct btrfs_path *path,
                                    struct list_head *data_refs,
                                    iterate_extent_inodes_t *iterate,
                                    void *ctx)
{
        u64 disk_byte;
        struct btrfs_key key;
        struct btrfs_file_extent_item *fi;
        struct extent_buffer *eb;
        int slot;
        int nritems;
        int ret;
        int found = 0;

        eb = read_tree_block(fs_info->tree_root, logical,
                                fs_info->tree_root->leafsize, 0);
        if (!eb)
                return -EIO;

        /*
         * from the shared data ref, we only have the leaf but we need
         * the key. thus, we must look into all items and see that we
         * find one (some) with a reference to our extent item.
         */
        nritems = btrfs_header_nritems(eb);
        for (slot = 0; slot < nritems; ++slot) {
                btrfs_item_key_to_cpu(eb, &key, slot);
                if (key.type != BTRFS_EXTENT_DATA_KEY)
                        continue;
                fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
                if (!fi) {
                        free_extent_buffer(eb);
                        return -EIO;
                }
                disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
                if (disk_byte != orig_extent_item_objectid) {
                        if (found)
                                break;
                        else
                                continue;
                }
                ++found;
                ret = __iter_shared_inline_ref_inodes(fs_info, logical,
                                                        key.objectid,
                                                        key.offset,
                                                        extent_offset, path,
                                                        data_refs,
                                                        iterate, ctx);
                if (ret)
                        break;
        }

        if (!found) {
                printk(KERN_ERR "btrfs: failed to follow shared data backref "
                        "to parent %llu\n", logical);
                WARN_ON(1);
                ret = -EIO;
        }

        free_extent_buffer(eb);
        return ret;
}

/*
 * calls iterate() for every inode that references the extent identified by
 * the given parameters. will use the path given as a parameter and return it
 * released.
 * when the iterator function returns a non-zero value, iteration stops.
 */
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
                                struct btrfs_path *path,
                                u64 extent_item_objectid,
                                u64 extent_offset,
                                iterate_extent_inodes_t *iterate, void *ctx)
{
        unsigned long ptr = 0;
        int last;
        int ret;
        int type;
        u64 logical;
        u32 item_size;
        struct btrfs_extent_inline_ref *eiref;
        struct btrfs_extent_data_ref *dref;
        struct extent_buffer *eb;
        struct btrfs_extent_item *ei;
        struct btrfs_key key;
        struct list_head data_refs = LIST_HEAD_INIT(data_refs);
        struct list_head shared_refs = LIST_HEAD_INIT(shared_refs);
        struct __data_ref *ref_d;
        struct __shared_ref *ref_s;

        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)(unsigned long)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);
}