btrfs-progs/libbtrfsutil/btrfsutil.h

398 lines
12 KiB
C

/*
* Copyright (C) 2018 Facebook
*
* This file is part of libbtrfsutil.
*
* libbtrfsutil is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* libbtrfsutil 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with libbtrfsutil. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef BTRFS_UTIL_H
#define BTRFS_UTIL_H
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/time.h>
#define BTRFS_UTIL_VERSION_MAJOR 1
#define BTRFS_UTIL_VERSION_MINOR 0
#define BTRFS_UTIL_VERSION_PATCH 0
#ifdef __cplusplus
extern "C" {
#endif
/**
* enum btrfs_util_error - libbtrfsutil error codes.
*
* All functions in libbtrfsutil that can return an error return this type and
* set errno.
*/
enum btrfs_util_error {
BTRFS_UTIL_OK,
BTRFS_UTIL_ERROR_STOP_ITERATION,
BTRFS_UTIL_ERROR_NO_MEMORY,
BTRFS_UTIL_ERROR_INVALID_ARGUMENT,
BTRFS_UTIL_ERROR_NOT_BTRFS,
BTRFS_UTIL_ERROR_NOT_SUBVOLUME,
BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND,
BTRFS_UTIL_ERROR_OPEN_FAILED,
BTRFS_UTIL_ERROR_RMDIR_FAILED,
BTRFS_UTIL_ERROR_UNLINK_FAILED,
BTRFS_UTIL_ERROR_STAT_FAILED,
BTRFS_UTIL_ERROR_STATFS_FAILED,
BTRFS_UTIL_ERROR_SEARCH_FAILED,
BTRFS_UTIL_ERROR_INO_LOOKUP_FAILED,
BTRFS_UTIL_ERROR_SUBVOL_GETFLAGS_FAILED,
BTRFS_UTIL_ERROR_SUBVOL_SETFLAGS_FAILED,
BTRFS_UTIL_ERROR_SUBVOL_CREATE_FAILED,
BTRFS_UTIL_ERROR_SNAP_CREATE_FAILED,
BTRFS_UTIL_ERROR_SNAP_DESTROY_FAILED,
BTRFS_UTIL_ERROR_DEFAULT_SUBVOL_FAILED,
BTRFS_UTIL_ERROR_SYNC_FAILED,
BTRFS_UTIL_ERROR_START_SYNC_FAILED,
BTRFS_UTIL_ERROR_WAIT_SYNC_FAILED,
};
/**
* btrfs_util_strerror() - Convert a libtrfsutil error code to a string
* description.
* @err: The error to convert.
*
* Return: Error description.
*/
const char *btrfs_util_strerror(enum btrfs_util_error err);
/**
* btrfs_util_sync() - Force a sync on a specific Btrfs filesystem.
* @path: Path on a Btrfs filesystem.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_sync(const char *path);
/**
* btrfs_util_sync_fd() - See btrfs_util_sync().
*/
enum btrfs_util_error btrfs_util_sync_fd(int fd);
/**
* btrfs_util_start_sync() - Start a sync on a specific Btrfs filesystem but
* don't wait for it.
* @path: Path on a Btrfs filesystem.
* @transid: Returned transaction ID which can be waited on with
* btrfs_util_wait_sync(). This can be %NULL.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_start_sync(const char *path,
uint64_t *transid);
/**
* btrfs_util_start_sync_fd() - See btrfs_util_start_sync().
*/
enum btrfs_util_error btrfs_util_start_sync_fd(int fd, uint64_t *transid);
/**
* btrfs_util_wait_sync() - Wait for a transaction with a given ID to sync.
* @path: Path on a Btrfs filesystem.
* @transid: Transaction ID to wait for, or zero for the current transaction.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_wait_sync(const char *path, uint64_t transid);
/**
* btrfs_util_wait_sync_fd() - See btrfs_util_wait_sync().
*/
enum btrfs_util_error btrfs_util_wait_sync_fd(int fd, uint64_t transid);
/**
* btrfs_util_is_subvolume() - Return whether a given path is a Btrfs subvolume.
* @path: Path to check.
*
* Return: %BTRFS_UTIL_OK if @path is a Btrfs subvolume,
* %BTRFS_UTIL_ERROR_NOT_BTRFS if @path is not on a Btrfs filesystem,
* %BTRFS_UTIL_ERROR_NOT_SUBVOLUME if @path is not a subvolume, non-zero error
* code on any other failure.
*/
enum btrfs_util_error btrfs_util_is_subvolume(const char *path);
/**
* btrfs_util_is_subvolume_fd() - See btrfs_util_is_subvolume().
*/
enum btrfs_util_error btrfs_util_is_subvolume_fd(int fd);
/**
* btrfs_util_subvolume_id() - Get the ID of the subvolume containing a path.
* @path: Path on a Btrfs filesystem.
* @id_ret: Returned subvolume ID.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_subvolume_id(const char *path,
uint64_t *id_ret);
/**
* btrfs_util_subvolume_id_fd() - See btrfs_util_subvolume_id().
*/
enum btrfs_util_error btrfs_util_subvolume_id_fd(int fd, uint64_t *id_ret);
/**
* btrfs_util_subvolume_path() - Get the path of the subvolume with a given ID
* relative to the filesystem root.
* @path: Path on a Btrfs filesystem.
* @id: ID of subvolume to set as the default. If zero is given, the subvolume
* ID of @path is used.
* @path_ret: Returned path.
*
* This requires appropriate privilege (CAP_SYS_ADMIN).
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_subvolume_path(const char *path, uint64_t id,
char **path_ret);
/**
* btrfs_util_subvolume_path_fd() - See btrfs_util_subvolume_path().
*/
enum btrfs_util_error btrfs_util_subvolume_path_fd(int fd, uint64_t id,
char **path_ret);
/**
* struct btrfs_util_subvolume_info - Information about a Btrfs subvolume.
*/
struct btrfs_util_subvolume_info {
/** @id: ID of this subvolume, unique across the filesystem. */
uint64_t id;
/**
* @parent_id: ID of the subvolume which contains this subvolume, or
* zero for the root subvolume (BTRFS_FS_TREE_OBJECTID) or orphaned
* subvolumes (i.e., subvolumes which have been deleted but not yet
* cleaned up).
*/
uint64_t parent_id;
/**
* @dir_id: Inode number of the directory containing this subvolume in
* the parent subvolume, or zero for the root subvolume
* (BTRFS_FS_TREE_OBJECTID) or orphaned subvolumes.
*/
uint64_t dir_id;
/** @flags: On-disk root item flags. */
uint64_t flags;
/** @uuid: UUID of this subvolume. */
uint8_t uuid[16];
/**
* @parent_uuid: UUID of the subvolume this subvolume is a snapshot of,
* or all zeroes if this subvolume is not a snapshot.
*/
uint8_t parent_uuid[16];
/**
* @received_uuid: UUID of the subvolume this subvolume was received
* from, or all zeroes if this subvolume was not received. Note that
* this field, @stransid, @rtransid, @stime, and @rtime are set manually
* by userspace after a subvolume is received.
*/
uint8_t received_uuid[16];
/** @generation: Transaction ID of the subvolume root. */
uint64_t generation;
/**
* @ctransid: Transaction ID when an inode in this subvolume was last
* changed.
*/
uint64_t ctransid;
/** @otransid: Transaction ID when this subvolume was created. */
uint64_t otransid;
/**
* @stransid: Transaction ID of the sent subvolume this subvolume was
* received from, or zero if this subvolume was not received. See the
* note on @received_uuid.
*/
uint64_t stransid;
/**
* @rtransid: Transaction ID when this subvolume was received, or zero
* if this subvolume was not received. See the note on @received_uuid.
*/
uint64_t rtransid;
/** @ctime: Time when an inode in this subvolume was last changed. */
struct timespec ctime;
/** @otime: Time when this subvolume was created. */
struct timespec otime;
/**
* @stime: Not well-defined, usually zero unless it was set otherwise.
* See the note on @received_uuid.
*/
struct timespec stime;
/**
* @rtime: Time when this subvolume was received, or zero if this
* subvolume was not received. See the note on @received_uuid.
*/
struct timespec rtime;
};
/**
* btrfs_util_subvolume_info() - Get information about a subvolume.
* @path: Path in a Btrfs filesystem. This may be any path in the filesystem; it
* does not have to refer to a subvolume unless @id is zero.
* @id: ID of subvolume to get information about. If zero is given, the
* subvolume ID of @path is used.
* @subvol: Returned subvolume information. This can be %NULL if you just want
* to check whether the subvolume exists; %BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND
* will be returned if it does not.
*
* This requires appropriate privilege (CAP_SYS_ADMIN).
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_subvolume_info(const char *path, uint64_t id,
struct btrfs_util_subvolume_info *subvol);
/**
* btrfs_util_subvolume_info_fd() - See btrfs_util_subvolume_info().
*/
enum btrfs_util_error btrfs_util_subvolume_info_fd(int fd, uint64_t id,
struct btrfs_util_subvolume_info *subvol);
/**
* btrfs_util_get_subvolume_read_only() - Get whether a subvolume is read-only.
* @path: Subvolume path.
* @ret: Returned read-only flag.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_get_subvolume_read_only(const char *path,
bool *ret);
/**
* btrfs_util_get_subvolume_read_only_fd() - See
* btrfs_util_get_subvolume_read_only().
*/
enum btrfs_util_error btrfs_util_get_subvolume_read_only_fd(int fd, bool *ret);
/**
* btrfs_util_set_subvolume_read_only() - Set whether a subvolume is read-only.
* @path: Subvolume path.
* @read_only: New value of read-only flag.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_set_subvolume_read_only(const char *path,
bool read_only);
/**
* btrfs_util_set_subvolume_read_only_fd() - See
* btrfs_util_set_subvolume_read_only().
*/
enum btrfs_util_error btrfs_util_set_subvolume_read_only_fd(int fd,
bool read_only);
struct btrfs_util_qgroup_inherit;
/**
* btrfs_util_create_subvolume() - Create a new subvolume.
* @path: Where to create the subvolume.
* @flags: Must be zero.
* @async_transid: If not NULL, create the subvolume asynchronously (i.e.,
* without waiting for it to commit it to disk) and return the transaction ID
* that it was created in. This transaction ID can be waited on with
* btrfs_util_wait_sync().
* @qgroup_inherit: Qgroups to inherit from, or NULL.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_create_subvolume(const char *path, int flags,
uint64_t *async_transid,
struct btrfs_util_qgroup_inherit *qgroup_inherit);
/**
* btrfs_util_create_subvolume_fd() - Create a new subvolume given its parent
* and name.
* @parent_fd: File descriptor of the parent directory where the subvolume
* should be created.
* @name: Name of the subvolume to create.
* @flags: See btrfs_util_create_subvolume().
* @async_transid: See btrfs_util_create_subvolume().
* @qgroup_inherit: See btrfs_util_create_subvolume().
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_create_subvolume_fd(int parent_fd,
const char *name,
int flags,
uint64_t *async_transid,
struct btrfs_util_qgroup_inherit *qgroup_inherit);
/**
* btrfs_util_create_qgroup_inherit() - Create a qgroup inheritance specifier
* for btrfs_util_create_subvolume() or btrfs_util_create_snapshot().
* @flags: Must be zero.
* @ret: Returned qgroup inheritance specifier.
*
* The returned structure must be freed with
* btrfs_util_destroy_qgroup_inherit().
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_create_qgroup_inherit(int flags,
struct btrfs_util_qgroup_inherit **ret);
/**
* btrfs_util_destroy_qgroup_inherit() - Destroy a qgroup inheritance specifier
* previously created with btrfs_util_create_qgroup_inherit().
* @inherit: Specifier to destroy.
*/
void btrfs_util_destroy_qgroup_inherit(struct btrfs_util_qgroup_inherit *inherit);
/**
* btrfs_util_qgroup_inherit_add_group() - Add inheritance from a qgroup to a
* qgroup inheritance specifier.
* @inherit: Specifier to modify. May be reallocated.
* @qgroupid: ID of qgroup to inherit from.
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
enum btrfs_util_error btrfs_util_qgroup_inherit_add_group(struct btrfs_util_qgroup_inherit **inherit,
uint64_t qgroupid);
/**
* btrfs_util_qgroup_inherit_get_groups() - Get the qgroups a qgroup inheritance
* specifier contains.
* @inherit: Qgroup inheritance specifier.
* @groups: Returned array of qgroup IDs.
* @n: Returned number of entries in the @groups array.
*/
void btrfs_util_qgroup_inherit_get_groups(const struct btrfs_util_qgroup_inherit *inherit,
const uint64_t **groups, size_t *n);
#ifdef __cplusplus
}
#endif
#endif /* BTRFS_UTIL_H */