restore_file_bsfs.c File Reference

Implementation of file restoration from the Recovery tree in BSFS. More...

Functions
int	restore_file_by_id (FILE *disk, superblock_t *sb, btree_handle_t *inode_tree, btree_handle_t *rec_tree, uint32_t recovery_id, const char *dest_dir_path, dir_t *cwd)
	Restore a file from the Recovery tree by its recovery ID.

Detailed Description

Implementation of file restoration from the Recovery tree in BSFS.

This module provides the routines necessary to restore a deleted file using its snapshot stored in the Recovery B-tree. Restoration consists of recreating the inode (reusing recorded data block mappings), linking a new directory entry in the chosen destination directory, and removing the snapshot from the Recovery tree upon success.

Function Documentation

restore_file_by_id()

int restore_file_by_id	(	FILE *	disk,
		superblock_t *	sb,
		btree_handle_t *	inode_tree,
		btree_handle_t *	rec_tree,
		uint32_t	recovery_id,
		const char *	dest_dir_path,
		dir_t *	cwd )

Restore a file from the Recovery tree by its recovery ID.

Semantics:

• Loads the snapshot from the Recovery B-tree using recovery_id.
• Determines the destination directory: if dest_dir_path is non-NULL, resolves it to a directory inode (relative to cwd if needed). If NULL or resolution fails, attempts to use the original parent recorded in the snapshot; if that is not available, falls back to cwd.
• Resolves name conflicts by appending a suffix containing the recovery ID, ensuring a unique filename in the destination directory.
• Recreates the inode from the snapshot (reusing its block mapping) and inserts it into the inode B-tree, updating sb->inode_root if the insertion creates the tree root.
• Creates a directory entry in the destination directory and updates its metadata timestamps.
• Removes the entry from the Recovery tree.

Parameters

disk	Open filesystem image.
sb	Loaded superblock (may be updated if inode root is first created during restore).
inode_tree	Inode B-tree handle (handle->root_block should be set from sb->inode_root if it already exists).
rec_tree	Recovery B-tree handle (handle->root_block should be set from sb->recovery_root).
recovery_id	Unique ID of the recovery snapshot to restore.
dest_dir_path	Optional destination directory path (absolute or relative to cwd). If NULL, attempt original parent then cwd.
cwd	Current working directory context for resolving relative paths and as a fallback destination.

Returns

0 on success; -1 on failure (snapshot not found, invalid destination, insertion or linking errors).