linux/fs/xfs/xfs_fsmap.h
Christoph Hellwig dcfc65befb xfs: clean up xfs_getfsmap_helper arguments
The calling conventions for xfs_getfsmap_helper are confusing -- callers
pass in an rmap record, but they must also supply startblock and
blockcount in daddr units.  This was bolted onto the original fsmap
implementation so that we could report *something* for realtime
volumes, which do not support rmap and hence can draw only from the rt
free space bitmap.  Free space on the rt volume can be more than 2^32
fsblocks long, which means that we can't use the rmap startblock or
blockcount fields.

This is confusing for callers, because they must supplying redundant
data, but not all of it is used.  Streamline this by creating a separate
fsmap irec structure that contains exactly the data we need, once.

Note that we actually do need rm_startblock for rmap key comparisons
when we're actually querying an rmap btree, so leave that field but
document why it's there.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2024-11-05 13:38:35 -08:00

49 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#ifndef __XFS_FSMAP_H__
#define __XFS_FSMAP_H__
struct fsmap;
struct fsmap_head;
/* internal fsmap representation */
struct xfs_fsmap {
dev_t fmr_device; /* device id */
uint32_t fmr_flags; /* mapping flags */
uint64_t fmr_physical; /* device offset of segment */
uint64_t fmr_owner; /* owner id */
xfs_fileoff_t fmr_offset; /* file offset of segment */
xfs_filblks_t fmr_length; /* length of segment, blocks */
};
struct xfs_fsmap_head {
uint32_t fmh_iflags; /* control flags */
uint32_t fmh_oflags; /* output flags */
unsigned int fmh_count; /* # of entries in array incl. input */
unsigned int fmh_entries; /* # of entries filled in (output). */
struct xfs_fsmap fmh_keys[2]; /* low and high keys */
};
/* internal fsmap record format */
struct xfs_fsmap_irec {
xfs_daddr_t start_daddr;
xfs_daddr_t len_daddr;
uint64_t owner; /* extent owner */
uint64_t offset; /* offset within the owner */
unsigned int rm_flags; /* rmap state flags */
/*
* rmapbt startblock corresponding to start_daddr, if the record came
* from an rmap btree.
*/
xfs_agblock_t rec_key;
};
int xfs_ioc_getfsmap(struct xfs_inode *ip, struct fsmap_head __user *arg);
#endif /* __XFS_FSMAP_H__ */