diff options
Diffstat (limited to 'fs/btrfs/export.c')
| -rw-r--r-- | fs/btrfs/export.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c new file mode 100644 index 00000000000..797b4cbc378 --- /dev/null +++ b/fs/btrfs/export.c @@ -0,0 +1,208 @@ +#include <linux/fs.h> +#include <linux/types.h> +#include "ctree.h" +#include "disk-io.h" +#include "btrfs_inode.h" +#include "print-tree.h" +#include "export.h" +#include "compat.h" + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28) +#define FILEID_BTRFS_WITHOUT_PARENT 0x4d +#define FILEID_BTRFS_WITH_PARENT 0x4e +#define FILEID_BTRFS_WITH_PARENT_ROOT 0x4f +#endif + +#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, parent_objectid)/4) +#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, parent_root_objectid)/4) +#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid)/4) + +static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len, + int connectable) +{ + struct btrfs_fid *fid = (struct btrfs_fid *)fh; + struct inode *inode = dentry->d_inode; + int len = *max_len; + int type; + + if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) || + (connectable && len < BTRFS_FID_SIZE_CONNECTABLE)) + return 255; + + len = BTRFS_FID_SIZE_NON_CONNECTABLE; + type = FILEID_BTRFS_WITHOUT_PARENT; + + fid->objectid = BTRFS_I(inode)->location.objectid; + fid->root_objectid = BTRFS_I(inode)->root->objectid; + fid->gen = inode->i_generation; + + if (connectable && !S_ISDIR(inode->i_mode)) { + struct inode *parent; + u64 parent_root_id; + + spin_lock(&dentry->d_lock); + + parent = dentry->d_parent->d_inode; + fid->parent_objectid = BTRFS_I(parent)->location.objectid; + fid->parent_gen = parent->i_generation; + parent_root_id = BTRFS_I(parent)->root->objectid; + + spin_unlock(&dentry->d_lock); + + if (parent_root_id != fid->root_objectid) { + fid->parent_root_objectid = parent_root_id; + len = BTRFS_FID_SIZE_CONNECTABLE_ROOT; + type = FILEID_BTRFS_WITH_PARENT_ROOT; + } else { + len = BTRFS_FID_SIZE_CONNECTABLE; + type = FILEID_BTRFS_WITH_PARENT; + } + } + + *max_len = len; + return type; +} + +static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, + u64 root_objectid, u32 generation) +{ + struct btrfs_root *root; + struct inode *inode; + struct dentry *result; + struct btrfs_key key; + + key.objectid = objectid; + btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); + key.offset = 0; + + root = btrfs_lookup_fs_root(btrfs_sb(sb)->fs_info, root_objectid); + inode = btrfs_iget(sb, &key, root, NULL); + if (IS_ERR(inode)) + return (void *)inode; + + if (generation != inode->i_generation) { + iput(inode); + return ERR_PTR(-ESTALE); + } + + result = d_obtain_alias(inode); + if (!result) + return ERR_PTR(-ENOMEM); + + return result; +} + +static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, + int fh_len, int fh_type) +{ + struct btrfs_fid *fid = (struct btrfs_fid *) fh; + u64 objectid, root_objectid; + u32 generation; + + if (fh_type == FILEID_BTRFS_WITH_PARENT) { + if (fh_len != BTRFS_FID_SIZE_CONNECTABLE) + return NULL; + root_objectid = fid->root_objectid; + } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) { + if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) + return NULL; + root_objectid = fid->parent_root_objectid; + } else + return NULL; + + objectid = fid->parent_objectid; + generation = fid->parent_gen; + + return btrfs_get_dentry(sb, objectid, root_objectid, generation); +} + +static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh, + int fh_len, int fh_type) +{ + struct btrfs_fid *fid = (struct btrfs_fid *) fh; + u64 objectid, root_objectid; + u32 generation; + + if ((fh_type != FILEID_BTRFS_WITH_PARENT || + fh_len != BTRFS_FID_SIZE_CONNECTABLE) && + (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT || + fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) && + (fh_type != FILEID_BTRFS_WITHOUT_PARENT || + fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE)) + return NULL; + + objectid = fid->objectid; + root_objectid = fid->root_objectid; + generation = fid->gen; + + return btrfs_get_dentry(sb, objectid, root_objectid, generation); +} + +static struct dentry *btrfs_get_parent(struct dentry *child) +{ + struct inode *dir = child->d_inode; + struct inode *inode; + struct dentry *parent; + struct btrfs_root *root = BTRFS_I(dir)->root; + struct btrfs_key key; + struct btrfs_path *path; + struct extent_buffer *leaf; + u32 nritems; + int slot; + u64 objectid; + int ret; + + path = btrfs_alloc_path(); + + key.objectid = dir->i_ino; + btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY); + key.offset = 0; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + BUG_ON(ret == 0); + ret = 0; + + leaf = path->nodes[0]; + slot = path->slots[0]; + nritems = btrfs_header_nritems(leaf); + if (slot >= nritems) { + ret = btrfs_next_leaf(root, path); + if (ret) { + btrfs_free_path(path); + goto out; + } + leaf = path->nodes[0]; + slot = path->slots[0]; + } + + btrfs_free_path(path); + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != dir->i_ino || key.type != BTRFS_INODE_REF_KEY) + goto out; + + objectid = key.offset; + + /* Build a new key for the inode item */ + key.objectid = objectid; + btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); + key.offset = 0; + + inode = btrfs_iget(root->fs_info->sb, &key, root, NULL); + + parent = d_obtain_alias(inode); + if (!parent) + parent = ERR_PTR(-ENOMEM); + + return parent; + +out: + btrfs_free_path(path); + return ERR_PTR(-EINVAL); +} + +const struct export_operations btrfs_export_ops = { + .encode_fh = btrfs_encode_fh, + .fh_to_dentry = btrfs_fh_to_dentry, + .fh_to_parent = btrfs_fh_to_parent, + .get_parent = btrfs_get_parent, +}; |