2008-07-20 14:31:56 -06:00
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#include <linux/fs.h>
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#include <linux/types.h>
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#include "ctree.h"
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#include "disk-io.h"
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#include "btrfs_inode.h"
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#include "print-tree.h"
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#include "export.h"
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#include "compat.h"
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
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#define FILEID_BTRFS_WITHOUT_PARENT 0x4d
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#define FILEID_BTRFS_WITH_PARENT 0x4e
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#define FILEID_BTRFS_WITH_PARENT_ROOT 0x4f
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#endif
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#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, parent_objectid)/4)
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#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, parent_root_objectid)/4)
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#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid)/4)
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static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
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int connectable)
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{
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struct btrfs_fid *fid = (struct btrfs_fid *)fh;
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struct inode *inode = dentry->d_inode;
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int len = *max_len;
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int type;
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if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) ||
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(connectable && len < BTRFS_FID_SIZE_CONNECTABLE))
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return 255;
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len = BTRFS_FID_SIZE_NON_CONNECTABLE;
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type = FILEID_BTRFS_WITHOUT_PARENT;
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fid->objectid = BTRFS_I(inode)->location.objectid;
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fid->root_objectid = BTRFS_I(inode)->root->objectid;
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fid->gen = inode->i_generation;
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if (connectable && !S_ISDIR(inode->i_mode)) {
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struct inode *parent;
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u64 parent_root_id;
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spin_lock(&dentry->d_lock);
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parent = dentry->d_parent->d_inode;
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fid->parent_objectid = BTRFS_I(parent)->location.objectid;
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fid->parent_gen = parent->i_generation;
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parent_root_id = BTRFS_I(parent)->root->objectid;
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spin_unlock(&dentry->d_lock);
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if (parent_root_id != fid->root_objectid) {
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fid->parent_root_objectid = parent_root_id;
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len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
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type = FILEID_BTRFS_WITH_PARENT_ROOT;
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} else {
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len = BTRFS_FID_SIZE_CONNECTABLE;
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type = FILEID_BTRFS_WITH_PARENT;
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}
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}
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*max_len = len;
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return type;
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}
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static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
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u64 root_objectid, u32 generation)
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{
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struct btrfs_root *root;
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struct inode *inode;
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struct dentry *result;
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struct btrfs_key key;
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2008-08-19 15:20:17 -06:00
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key.objectid = root_objectid;
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btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
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key.offset = (u64)-1;
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root = btrfs_read_fs_root_no_name(btrfs_sb(sb)->fs_info, &key);
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if (IS_ERR(root))
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return ERR_CAST(root);
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2008-07-20 14:31:56 -06:00
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key.objectid = objectid;
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btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
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key.offset = 0;
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inode = btrfs_iget(sb, &key, root, NULL);
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if (IS_ERR(inode))
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return (void *)inode;
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if (generation != inode->i_generation) {
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iput(inode);
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return ERR_PTR(-ESTALE);
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}
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result = d_obtain_alias(inode);
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if (!result)
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return ERR_PTR(-ENOMEM);
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return result;
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}
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static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
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int fh_len, int fh_type)
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{
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struct btrfs_fid *fid = (struct btrfs_fid *) fh;
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u64 objectid, root_objectid;
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u32 generation;
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if (fh_type == FILEID_BTRFS_WITH_PARENT) {
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if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
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return NULL;
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root_objectid = fid->root_objectid;
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} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
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if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
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return NULL;
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root_objectid = fid->parent_root_objectid;
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} else
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return NULL;
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objectid = fid->parent_objectid;
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generation = fid->parent_gen;
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return btrfs_get_dentry(sb, objectid, root_objectid, generation);
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}
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static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
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int fh_len, int fh_type)
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{
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struct btrfs_fid *fid = (struct btrfs_fid *) fh;
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u64 objectid, root_objectid;
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u32 generation;
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if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
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fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
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(fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
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fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
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(fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
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fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
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return NULL;
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objectid = fid->objectid;
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root_objectid = fid->root_objectid;
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generation = fid->gen;
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return btrfs_get_dentry(sb, objectid, root_objectid, generation);
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}
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static struct dentry *btrfs_get_parent(struct dentry *child)
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{
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struct inode *dir = child->d_inode;
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struct inode *inode;
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struct dentry *parent;
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struct btrfs_root *root = BTRFS_I(dir)->root;
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struct btrfs_key key;
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struct btrfs_path *path;
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struct extent_buffer *leaf;
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int slot;
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u64 objectid;
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int ret;
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path = btrfs_alloc_path();
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key.objectid = dir->i_ino;
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btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
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2008-08-18 15:50:22 -06:00
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key.offset = (u64)-1;
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2008-07-20 14:31:56 -06:00
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2008-08-18 15:50:22 -06:00
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ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
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2008-07-20 14:31:56 -06:00
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leaf = path->nodes[0];
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slot = path->slots[0];
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2008-08-18 15:50:22 -06:00
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if (ret < 0 || slot == 0) {
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btrfs_free_path(path);
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goto out;
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2008-07-20 14:31:56 -06:00
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}
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2008-08-18 15:50:22 -06:00
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/* btrfs_search_slot() returns the slot where we'd want to insert
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an INODE_REF_KEY for parent inode #0xFFFFFFFFFFFFFFFF. The _real_
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one, telling us what the parent inode _actually_ is, will be in
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the slot _before_ the one that btrfs_search_slot() returns. */
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slot--;
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2008-07-20 14:31:56 -06:00
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2008-08-18 15:50:22 -06:00
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btrfs_item_key_to_cpu(leaf, &key, slot);
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2008-07-20 14:31:56 -06:00
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btrfs_free_path(path);
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if (key.objectid != dir->i_ino || key.type != BTRFS_INODE_REF_KEY)
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goto out;
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objectid = key.offset;
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2008-08-19 15:20:17 -06:00
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/* If we are already at the root of a subvol, return the real root */
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if (objectid == dir->i_ino)
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return dget(dir->i_sb->s_root);
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2008-07-20 14:31:56 -06:00
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/* Build a new key for the inode item */
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key.objectid = objectid;
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btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
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key.offset = 0;
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inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
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parent = d_obtain_alias(inode);
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if (!parent)
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parent = ERR_PTR(-ENOMEM);
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return parent;
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out:
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btrfs_free_path(path);
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return ERR_PTR(-EINVAL);
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}
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const struct export_operations btrfs_export_ops = {
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.encode_fh = btrfs_encode_fh,
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.fh_to_dentry = btrfs_fh_to_dentry,
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.fh_to_parent = btrfs_fh_to_parent,
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.get_parent = btrfs_get_parent,
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};
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